MUDDY FEET - Auckland Regional Council

MUDDY FEET 

FIRTH OF THAMES RAMSAR SITE 

UPDATE 

2004 

Pivotal Ecosystem in the Hauraki Gulf 

EcoQuest Education Foundation Report Series No. 1

Frontispiece 

Chart of the Hauraki Gulf (1827) 

From Dumont d’Urville – Voyage de l’Astrolabe 

Showing the Waihou River and the “Ware-kawa” Miranda-Kaiaua Coast 

(present Ramsar Site)

MUDDY FEET 

FIRTH OF THAMES RAMSAR SITE 

UPDATE 2004 

Bill Brownell, Editor 

Dedicated 

to 

Stella Frances 

Published by 

EcoQuest Education Foundation 

East Coast Road, Kaiaua 

RD 3, Pokeno, New Zealand

A report prepared for Environment Waikato 

(an Environmental Initiatives Project) 

and 

Hauraki District Council 

Thames Coromandel District Council 

Copyright December 2004, EcoQuest Education Foundation 

ISBN 0-9582329-1-1 

Cover 

Drawing of Pacific Golden Plover (Pluvialis fulva) by Keith Woodley 

Photo of Deb Kast and Becca Hanson (Homo sapiens) on bank of Karito Canal by Bill Brownell

Contents 

List of Figures 

List of Tables 

Memory of Tikapa Moana 

Acknowledgements 

Preface 

1 INTRODUCTION................................................................................................. 1 

1.1 Wetlands in New Zealand ............................................................................. 1 

1.2 The Ramsar Convention................................................................................ 1 

1.3 General Description of the Firth of Thames.................................................. 2 

1.4 Catchment...................................................................................................... 8 

1.5 The Firth of Thames Ramsar Site.................................................................. 8 

1.6 Brief History of Hauraki Plains Reclamation Works and Drainage ............. 9 

2 HYDROLOGY.................................................................................................... 13 

2.1 Hauraki sediments ....................................................................................... 13 

2.2 Summary of Cheatley (2000) ...................................................................... 15 

3 VEGETATION.................................................................................................... 17 

3.1 Miranda – Kaiaua foreshore........................................................................ 17 

3.2 Survey of the foreshore between Tararu and Hot Springs Drain ................ 20 

3.3 Grazing ........................................................................................................ 23 

3.4 Threatened plants of Miranda...................................................................... 24 

3.5 Threatened plants inside the stopbank......................................................... 25 

3.6 Exotic invaders – Adventive plant species.................................................. 26 

4 TERRESTRIAL INVERTEBRATES & MAMMALIAN PREDATORS.......... 31 

4.1 Mammalian Predators.................................................................................. 31 

4.2 Invertebrates ................................................................................................ 32 

4.3 Brown Garden Snail .................................................................................... 32 

4.4 Mangroves................................................................................................... 32 

5 MANGROVES: THE CORNERSTONE OF A DYNAMIC COASTAL 

ENVIRONMENT........................................................................................................ 34 

5.1 History......................................................................................................... 34 

5.2 Ecology........................................................................................................ 34 

5.3 Accretion of Sediments and Advancement of Mangroves.......................... 38 

5.4 Karito Canal Field Studies .......................................................................... 44 

5.5 Dredging in the Mangroves......................................................................... 44 

5.6 Revegetation of the Spoils Area.................................................................. 49 

5.7 Recovery of the Dieback Area .................................................................... 49 

5.8 Effects of Frost ............................................................................................ 51 

5.9 Conclusions ................................................................................................. 52 

6 BIRDS OF THE MIRANDA COAST ................................................................ 54 

6.1 Introduction ................................................................................................. 54 

6.2 Birds of Miranda and the Firth of Thames .................................................. 54 

6.3 Survey of the foreshore between Tararu and Hot Springs Drain ................ 59 

6.4 Principal Waders ......................................................................................... 60

6.5 Other Wader Species................................................................................... 65 

6.6 Wetland Birds and Waterfowl..................................................................... 66 

6.7 Oceanic and Sea-birds................................................................................. 68 

6.8 Terrestrial Species ....................................................................................... 71 

7 ESTUARINE FISH, FISHERIES AND MARINE FARMING.......................... 77 

7.1 Introduction ................................................................................................. 77 

7.2 Recent Biological Phenomena in the Firth of Thames................................ 78 

7.3 Marine Farming in the Firth of Thames ...................................................... 80 

7.4 Fishing Activity in the Firth of Thames ...................................................... 81 

7.5 Stream fish surveys ..................................................................................... 87 

7.6 Fisheries Research....................................................................................... 87 

7.7 Conclusions ................................................................................................. 88 

8 BENTHIC ECOLOGY........................................................................................ 91 

8.1 Introduction ................................................................................................. 91 

8.2 Methodology ............................................................................................... 91 

8.3 Results ......................................................................................................... 93 

8.4 Summary & Conclusions............................................................................. 98 

8.5 Recommendations ..................................................................................... 100 

8.6 Introduction ............................................................................................... 102 

8.7 Study site ................................................................................................... 103 

8.8 Sampling Methods..................................................................................... 103 

8.9 Results ....................................................................................................... 103 

8.10 Discussion ................................................................................................. 106 

8.11 Continuation of the study .......................................................................... 106 

9 LAND TENURE / STATUTORY MANAGEMENT....................................... 108 

9.1 Introduction ............................................................................................... 108 

9.2 Land Tenure .............................................................................................. 108 

9.3 Legislation................................................................................................. 108 

9.4 Statutory Management .............................................................................. 109 

9.5 Functions, Policies and Plans .................................................................... 110 

9.6 Treaty of Waitangi matters........................................................................ 118 

9.7 Strategies, Policies and Plans .................................................................... 119 

9.8 Resource Management Act Policies and Plans ......................................... 120 

9.9 Discussion ................................................................................................. 121 

10 RAISING CONSERVATION AWARENESS ................................................. 123 

10.1 Introduction ............................................................................................... 123 

10.2 Department of Conservation ..................................................................... 123 

10.3 Ramsar Convention Work Plan, 2000-2002.............................................. 127 

10.4 Other Initiatives......................................................................................... 127 

10.5 Miranda Naturalists’ Trust ........................................................................ 127 

10.6 Improving Interpretation, Access and Advocacy...................................... 128 

10.7 Support for Research and Advocacy......................................................... 129 

11 RISKS, THREATS AND CURRENT RESEARCH......................................... 130 

11.1 Summary of the Issues .............................................................................. 130 

11.2 Specific concerns about the immediate catchment: .................................. 133 

11.3 From outside the catchment: ..................................................................... 134 

11.4 Uses of the Firth of Thames and Hauraki Gulf ......................................... 134 

11.5 Cross-boundary issues............................................................................... 135 

11.6 Global links ............................................................................................... 135

11.7 Current Research in the Firth of Thames .................................................. 136 

11.8 Pertinent Research in Neighbouring Areas ............................................... 139 

12 FIRTH OF THAMES RAMSAR SITE WORKSHOP REPORT MIRANDA 

SHOREBIRD CENTRE, NOVEMBER 16, 2001 ....................................................... 141 

12.1 Introduction ............................................................................................... 141 

12.2 Land use, water quality and sedimentation ............................................... 141 

12.3 Coastal Vegetation .................................................................................... 143 

12.4 Benthic Ecology ........................................................................................ 146 

12.5 Fish, fisheries and aquaculture .................................................................. 147 

12.6 Birds .......................................................................................................... 149 

12.7 Enhancement of community participation, recreation and natural 

history education in the area...................................................................... 151 

12.8 Achieving sustainability of the Ramsar site in the context of the Firth 

of Thames ecosystem, and protection of ecosystem values, cultural 

heritage and historical features.................................................................. 153 

12.9 How to move forward with issues-focussed research requirements 

identified by the EcoQuest report, today’s discussions and the May 24 

DoC workshop........................................................................................... 155 

13 CONCLUSIONS AND RECOMMENDATIONS............................................ 160 

13.1 General Conclusions.................................................................................. 160 

13.2 Recommendations ..................................................................................... 163 

14 BIBLIOGRAPHY ............................................................................................. 165 

Muddy knees, too... Dick Veitch (photo K. Woodley)

List of Figures 

Figure 1-1 Southern Hauraki Gulf and the Firth of Thames. The Ramsar Site sits 

between the low tide mark and the coast, extending from the Waihou River 

to Kaiaua. The five political districts and two regions bordering the Firth 

are shown ................................................................................................................3 

Figure 1-2 Aerial view of the eastern end of the Ramsar Site, showing the 

Waihou and Piako river mouths, the stopbanks, farmland and the band of 

coastal mangroves. ..................................................................................................4 

Figure 1-3 Aerial composite of the Firth of Thames, with a close-up of one point 

along the stop bank near the Piako River mouth.....................................................6 

Figure - 5-1 June, 1963 aerial photo of Waitakaruru River to Karito Canal area, 

showing minimal coastal mangrove coverage. .....................................................41 

Figure - 5-2 Waitakaruru-Karito area in 1996, showing mangrove advancement. .........42 

Figure - 5-3: Waitakaruru River to Karito Canal - February 2002.....................................43 

Figure - 5-4 Three time series photos of the dredge spoils strip along the Karito 

Canal .....................................................................................................................45 

Figure - 5-5 Photo of Karito Canal before dredging, and 2 time series photos of 

the Karito mangrove dieback area.........................................................................47 

Figure 5-6 December 2004 updated mangroves photos ...................................................48 

Figure 6-1 Important Sites for waders and shorebirds in New Zealand (indicated 

by bold italics).......................................................................................................55 

Figure 6-2 Wader habitats at Firth of Thames Ramsar Site .............................................56 

Figure 6-3 Changing habitats at Miranda (adapted from Veitch and Habraken 

1999, by permission).............................................................................................57 

Figure 6-4 Wader watchers: a common sight at Miranda and Taramaire from 

October to April (photo K. Woodley)...................................................................73 

Figure 8-1 Study area and location of 10 transects (sites) and 30 sampling stations 

at 3 approximate tidal elevations within the Firth of Thames Ramsar Site 

and nearby Thames Coast. Note: The Miranda near-shore sampling station 

(see section 2) is approximately beneath the letter ‘a’ of station 9a. ....................92 

Figure 8-2 Scale approximation of size and density of M. ovata tristis as recorded 

in one core sample station (6a)..............................................................................96 

Figure 8-3 Estimated abundances/m2 of main benthic faunal groups at each site: 

Polychaeta, Decapoda, Crustacea and Bivalvia. Note: Capitellidae 

abundances have been omitted because they were only scored on a 

present/absent basis, n = 9 cores.........................................................................96 

Figure 8-4 Estimated abundance/m2 of the six most prevalent bivalve species 

recorded per transect from 9 × 15 cm dia. cores (3 samples × 3 sites). ................97 

Figure 8-5 Estimated abundances (m2) of four main benthic faunal groups for each 

tidal elevation. Sites ‘A’ » MHW, sites ‘B’ » mid tide, sites ‘C’ » MLWS. 

Note: Oligochaete abundances have been omitted because they were only 

scored on a present/absent basis............................................................................97 

Figure 8-6 Estimated abundance (m2) of four most prevalent bivalve species 

recorded for each tidal elevation. Note: 9 × 15 cm dia. cores (3 samples × 3 

sites). Sites ‘A’ » MHW, sites ‘B’ » mid tide, sites ‘C’ » MLWS.......................98 

Figure 8-7 Dominant taxa divided into functional feeding groups for stations A-C........99 

Figure 9-1 Zoning map of Thames-Kopu area showing Waihou River, Firth of 

Thames and coastal land uses .............................................................................115 

Figure 9-2 Zoning map of Kaiaua-Miranda Coast showing designation and land 

status (Dept. of Conservation and Franklin District Council jurisdictions)........117 

Figure 9-3 Planning Framework of the Resource Management Act ..............................120

List of Tables 

Table 5-1 Comparative Widths in metres of Firth of Thames Ramsar Site 

Mangrove Forest – 1977 and 2002 - at selected points around the coast, 

starting from the outer edges of the stopbanks and extending out to the 

edge of the highest density zone...................................................................... 40 

Table 8-1 Summary of raw data indicating total number of species recorded at 

each site (numbers represent a composite of three replicate core 

samples)........................................................................................................... 94 

Table 8-2 Berger-Parker dominance measures for the composite data (30 cores 

each) of the three stations (A-C), plus some selected extreme examples 

from individual stations (three cores each)...................................................... 95 

Table 8-3 Mean size parameters taken from sub-sample of typical adult 

specimens......................................................................................................... 96 

Table 8-4 Description, sampling technique and sample volume associated with 

each sampling device..................................................................................... 103 

Table 8-5 Comparison of sampling devices when plots were exposed and 

submerged. Standardized to 1 litre of sediment [Organisms are totals of 

ten samples, collected in March 2001.] ......................................................... 104 

Table 8-6 Two way ANOVA comparing variance associated different methods 

and sampling tides (exposed and covered) on day 1 ..................................... 104 

Table 8-7 Two way ANOVA comparing variance associated different methods 

and sampling tides (exposed and covered) for day 2..................................... 104 

Table 8-8 Total for organisms collected in ten Coff-Kyd samples in Plot A - 

March and May 2001. Volume standardized to 1 litre of sediment. ............. 105 

Table 8-9 List of Taxa found in Benthic Fauna Samples at Miranda....................... 105 

Table 9-1 Resource Management Responsibilities ................................................... 119

Early morning light … 

shadows shaping 

movement making 

a flat flight 

to land upon rounded washed 

stones 

held as islands between tides. 

Kotare 

Kotare the kingfisher … 

staunch 

expectant 

a keenness stilled 

pregnant with silence, waiting 

Kotaretare tapu 

the one looking over 

that which is sacred. 

Kotare converses with old Moki 

talking the language of Manawa 

Manawa … heartseed of mangrove 

Together they speak, 

as elders they listen. 

‘Whakarongo’ … listen here 

Kia ora, e hoa 

I watch you, Moki … 

tides of movement, 

kelped wavebent shore of Hauraki 

guarding these waters 

with your trusting love. 

Old eyes … 

you leave me 

with feelings 

on the edge of unease 

that ‘they’ may know not ever 

until their time 

to swim beside you nears. 

The Memory of Tikapa Moana 

Aue, Manawa 

Old mangrove … 

by this breath, this heart 

I lament. 

What have they done to the land, 

what do they do to the sea … 

Manawa … 

ancient mind 

to remind them 

privilege given. 

Incredulous 

they behave 

this only about them. 

Are elders not placed 

by circumspect 

to respect 

to listen … 

Mana 

Manawa 

Mana whenua 

For whose pulse is this 

that lies in rhythm 

to this primordial 

mother’s heart … 

Listen to the land 

Listen to the sea 

Mana whenua 

Mana moana 

Whakarongo 

Listen. 

Mike O’ Donnell 

Paeroa

Acknowledgements 

This report was made possible by a grant from Environment Waikato’s Environmental 

Initiatives Fund. Substantial additional funding was provided by the Hauraki District Council 

and the Thames Coromandel District Council. The Waikato District Council donated a full 

set of 1996 colour aerial photographs of the area. The Department of Conservation 

(Auckland and Waikato Conservancies) provided valuable support services and advice. 

The 2001 draft of Muddy Feet was printed and circulated to 80 collaborators and interested 

parties in November 2001. My most profound appreciation goes to my principal EcoQuest 

collaborators, in particular the co-editor of that edition, Ria Brejaart. Jono Clark has played a 

major role in the organisation, layout and formatting of both editions. Marie Buchler made 

major editing and content contributions to this 2004 edition, including the transcription of the 

proceedings of the 2001 Workshop at the Miranda Shorebird Centre. 

I am grateful to all who assisted us with their valuable editorial comment on the draft of this 

document, particularly to Malene Felsing and her predecessor Stephanie Turner at 

Environment Waikato, and Marina Van Steenbergen at Hauraki District Council. Those who 

reviewed specific parts of it for us were: Rex Smith of Waitakaruru; Chris Paulin of the 

National Museum; David Medway of New Plymouth; Bev Clarkson and Bruce Burns of 

Landcare Research; Bec Stanley, Rosalie Stamp and Kala Sivaguru of DoC Auckland; Jan 

Simmons, Andrea Brandon and Tony Roxburgh of DoC Waikato; Larry Paul and Simon 

Thrush of NIWA; Keith Woodley of the Miranda Shorebird Centre. Nathan Kennedy of 

TCDC produced the special Thames area map. 

During the more than six years of planning and execution of this study, we received valuable 

information, advice and/or moral support from the following individuals: 

Peter Singleton, Robin Britten, Kathy Brightwell, Beat Huser, Gill Lawrence, Rick Liefting, 

Bill Vant, Sherilynn Hinton, Tony Fenton, Rosalind Wilton and Evan Penny (Environment 

Waikato-Hamilton), 

Ian Sara, Owen Passau, Kevin Campbell and Mark Soulsby (Environment Waikato-Paeroa), 

Alan Turner (Waikato District Council), 

Peter Wishart, Gary Deadman and Rowena Buchanan (Thames Coromandel DC), 

Mike Maguire, Steve Clark, Morgan Davison and Langley Cavers (Hauraki DC), 

Alan Moore, Dominic McCarthy, Neil Olsen and the librarians (Auckland Regional Council), 

Keith Woodley, David Lawrie, John Gale, Adrian Riegen, Dick Vietch, Tony Habraken, Phil 

Battley and Warwick Sandler (Miranda Naturalists’ Trust), 

Liane Ngamene (Hauraki Maori Trust Board) and David Taipari (Ngati Maru), 

Andy Andrews, Polly Wilson, Lucy Tukua, Amy Thompson and Tu Andrews (Ngati Paoa), 

Mal Green, Mark Morrison, John Zeldis and Simon Thrush (NIWA), 

Maggie Lawton, Bruce Burns and Bev Clarkson (Landcare Research, Hamilton), 

Jan Simmons, Tony Roxburgh, John Gumbley, Vicki Carruthers, Des Williams, Tracie Dean, 

Lisette Collins, Joe Harawira, Dave West and Fiona Edwards (DoC Waikato, Hamilton), 

Jason Roxburgh, John Gaukrodger and Fin Buchanan (DoC Waikato, Hauraki),

Stella Frances, Jan Coates, Warwick Murray, Bec Stanley, Annie Wheeler, Rau Kapa, Ian 

Bradley, Marie Alpe, Linda Bercusson, Roger Grace and Marilyn Fullam (DoC Auckland), 

Chris Hendy, Conrad Pilditch, Brendan Hicks, Catherine Beard, Rebecca Cheatley, Hilke 

Giles and Willem de Lange (Waikato University), 

Marjorie van Roon, Bob Creese and Bert Mom (Auckland University), 

Kathy Walsh (Kaiaua Citizens’ and Ratepayers’ Association, Auckland Conservation Board) 

Rex Smith, Mark Aislabie, Bert Laing, Ted Howard, Stephen Lane, Jocelyn Lane, Peter 

Thorburn, Doug Pulford and Jagindar Singh (local residents), 

David Medway (NZ Ornithological Society), 

Eric Souchon (H.G. Leach, Paeroa), 

Mike Tuohy and his students of remote sensing (Massey University) 

The EcoQuest team, all of whom assisted in various ways in the field and at the EcoQuest 

headquarters: Holly Bogle, Scott Bogle, Brian Coffey, Tony Cummings, Donna Dowal, Nigel 

Keeley, John Longden, Peter Maddison, Elizabeth Jones, Rob Ruzicka, Patrick Stewart, Jae 

Strommer, Stephanie Todd, Bruce and Meg Wildblood-Crawford, and numerous students 

who contributed to the ecological studies of wader birds, mudflats and mangroves. 

And, most of all, to John Clark, an immense and persistant source of inspiration and 

encouragement to so many of us who are passionate about the whenua of Hauraki and the 

moana of Tikapa, and who was the principal kaitiaki of the wairua of this and many other 

similar initiatives over the past 14 years. 

Appropriately muddy feet of the Summer Bird Course - Miranda Naturalists’ Trust 

(photo K. Woodley)

Preface 

Muddy feet. All resident and visiting species (plant, animal and human) in the Firth of 

Thames Ramsar Site have them, except for the ones that only swim. This vast intertidal area 

at the southern (hereafter referred to as ‘upper’) end of the Firth of Thames (Tikapa Moana) is 

mainly composed of muddy sediments that have built up there over time. Many species (such 

as mangrove, ducks, herons, flounders, eels, mud crabs, oysters and mud snails) thrive in the 

mud. The original flood plain forests and savannah of the Hauraki and Hunua coastal plains 

used to absorb it and replenish it. Adjoining ocean and riparian systems depend on it in many 

ways. Stop banks now defend against it. Humans tend to avoid it, unless they are shellfish 

gatherers, fishers, ornithologists, estuarine ecologists, duck hunters, farmers rescuing stray 

cattle, mud castle-building children or those passing through it by boat at high tide on their 

way to somewhere else. 

In spite of having been extremely modified by human activity, particularly over the past 130 

years, the upper end of the Firth of Thames remains an exceptionally productive ecosystem 

that provides quality shelter and abundant food for a great diversity of estuarine, coastal and 

avian species. Land use in the catchment is predominantly agricultural. 

Since the late 1970s, the intertidal zone of the upper Firth had been seriously considered for 

specific national protective status. Although a significant portion of this coast, extending 

from Kaiaua in the west around to the Waihou River in the southeast, was officially 

recognized as an internationally important wetland habitat by its designation as a Ramsar site 

in January 1990, no integrated ecosystem research was carried out in the area either before or 

after the designation, and no specific national protective status has been granted. 

There have been a number of isolated studies on the ecology, natural history and hydrology of 

the area. The primary focus of specific biological and ecological studies of the Ramsar site 

has been on the waders and their habitat. The goals of the present study were to gather and 

review existing information about the southern Firth of Thames ecosystem, and about the 

Ramsar Site in particular. Selected field investigations into aspects of the current state of the 

Ramsar Site were carried out. Findings of the literature review, local knowledge and field 

investigations, including the appraisal of conservation issues and increased pressures for 

development in the surrounding area are presented in this report. In addition, gaps in existing 

knowledge have been highlighted. 

Research for the Hauraki Customary Indicators Report (1999) was underway when our study 

of the Ramsar Site began. In parts, the Customary Indicators Report and Muddy Feet are 

complementary. A workshop on “Biological Investigations of the Firth of Thames”, 

organized by the Waikato Conservancy of the Department of Conservation, was held in May 

2001 at the Miranda Shorebird Centre, followed closely by the Ramsar Site Workshop at the 

same venue in November (proceedings reported here as chapter 12). Management issues, 

current risks and priorities for further research and policy development that were identified at 

these workshops have been incorporated in this report. 

We have drawn ideas and inspiration from many residents, visiting naturalists and researchers 

who collectively have a wealth of experience and vision about this upper Firth of Thames 

environment. All who have hands-on involvement with this area (and the inevitable muddy 

feet) recognise that this ecosystem is evolving very rapidly, and the changes are profound. 

These changes are begging to be documented and evaluated in terms of ecosystem evolution, 

and the existing and potential human impacts. We hope that this work will encourage all 

concerned Ramsar Site stakeholders to contribute to a greater collective understanding of how 

it functions, and how to achieve integrated and sustainable management of it. 

Bill Brownell – December 2004

Mouth of the Miranda Stream: start of the coastal band of mangroves (background) looking SW 

toward location 1 in table 5.1 (photo K. Woodley) 

New shellbank at Miranda: slow evolution since 1996: rapid expansion in 2004 

(photo K. Woodley)

1 Introduction 

by Ria Brejaart and Bill Brownell 

(with contributions by Holly Bogle and Nigel Keeley) 

1.1 Wetlands in New Zealand 

The mountains, plains, plateaus and rough coastlines of New Zealand, and the variety of 

physical processes acting upon them – wind and rain, rivers and streams, waves and tides, 

floods, earthquakes, glacial and volcanic activity – have combined to form an extensive 

network of coastal and interior wetlands. These important wildlife habitats, repositories of 

nutrients for recycling and buffers against flooding have gained prominence in recent years, 

after many years of being considered a nuisance. 

In the Waikato Region in 1865 there were fewer, but much larger wetlands. Today, after 150 

years of drainage, the large wetlands like the Hauraki flood plain adjacent to the Firth of 

Thames have been lost or split into small fragments, and most are now smaller than 50 ha. 

The National Wetland Trust was established in 1999 to increase the appreciation of wetlands 

and their values by all New Zealanders. The Trust plans to build a state-of-the-art wetland 

interpretation centre near Lake Kopuera, in the northern Waikato Region. 

Wetlands have been used, altered and drained by both Maori and Europeans. It is estimated 

that only 10% of New Zealand’s former wetlands remain (Cromarty and Scott, 1996). 

Wetlands in the Waikato Region include peat bogs, shallow lakes, extensive freshwater bogs, 

and river flats, as well as vast estuarine wetlands, of which the lower Firth of Thames is the 

largest. Extraction of sand and gravel, land reclamation, drainage, run-off, residential 

developments, and the spread of mangroves and exotic weeds are some of the processes that 

bring about ongoing changes to New Zealand’s wetlands today (Cromarty and Scott, 1996). 

The coastal wetland and mudflats that constitute the present Firth of Thames Ramsar Site is a 

result of perhaps the most severe wetland modification ever undertaken in New Zealand: the 

conversion of over 200,000 acres of the original Piako Swamp into fully drained, prime 

agricultural land. The mangrove forests that today cover 1100 hectares of coastal margin in 

the southern Firth barely existed in 1952, mainly as a few small patches at the mouths of the 

Piako and Waihou rivers. 

1.2 The Ramsar Convention 

The Convention on Wetlands of International Importance Especially as Waterfowl Habitat is 

an intergovernmental treaty, adopted on 2 February 1971 in the Iranian city of Ramsar, and is 

commonly known and referred to as the Ramsar Convention. Although the emphasis 

originally was on the provision of habitat for waterfowl and waders, the Convention has in 

recent years broadened its scope, recognizing the importance of wetland ecosystems for 

biodiversity conservation and for the well-being of human communities. By July 2000, the 

Convention had 122 Contracting Parties in all parts of the world, with 1031 wetlands that had 

been designated for inclusion in the List of Wetlands of International Importance, covering 

78.2 million hectares. 

Upon joining, contracting parties must fulfil four major obligations: 

• Designation of at least one wetland for inclusion in the List of Wetlands of International 

Importance, and promotion of its conservation, and where appropriate, its wise use. 

• Inclusion of wetland conservation considerations in planning at a national level. 

EcoQuest Education Foundation EQRS/1 12/04 

1

2 

• Establishment of nature reserves in wetlands, and promotion of training in the fields of 

wetland research and management. 

• Consultation with other Contracting Parties about implementation of the Convention. 

The first Oceania regional meeting of the Ramsar Convention was held in Hamilton, New 

Zealand in December 1998. New Zealand has designated five wetlands for inclusion in the 

List of Wetlands of International Importance, three of which are in the Waikato Region. 

Chronologically, from date of designation, these are: 

• Farewell Spit and the Waituna Wetland (both August 1976) – South Island 

• Whangamarino and Kopuatai Peat Dome (both December 1989) – Waikato 

• Firth of Thames (January 1990) – a short distance NE of Whangamarino and Kopuatai 

The April 2001 report from the Auditor General of New Zealand on Meeting International 

Environmental Obligations points to some weaknesses in our wetlands standards, citing the 

“…. lack of a coherent national policy framework on wetlands.” and, “There is also evidence 

that wetland degradation in New Zealand is worse than it ought to have been. To an extent 

this may have been inevitable. But it is probable that the cause lies, in part, in the lack of 

guidance – both in legislative and policy terms – on where the balance should lie between 

development and wetland protection. We believe the variability and differing values of 

wetlands lead directly to difficulties in application and implementation of the Ramsar 

Convention. And these difficulties reinforce the need to develop a national wetlands planning 

framework to set priorities, targets, standards, and so on within an agreed understanding of 

the Convention obligation of as far as possible the wise use of wetlands.” 

1.3 General Description of the Firth of Thames 

The Firth of Thames, or Tikapa Moana, is a shallow marine embayment, which lies in the 

northern part of the Hauraki Rift, bounded by fault lines along the Hunua and Coromandel 

ranges (see 1.6). The Firth’s northern boundary, merging into the greater Hauraki Gulf, is 

situated due east of Auckland, running from Thumb Point (NE Waiheke Island) to 

Coromandel Harbour, approximately following the line of 36º44' S latitude, between 175º11' 

and 175º31' E longitude (Figure 1-1). The Firth is between eleven and fourteen nautical miles 

wide and reaches a maximum depth of 35 metres near its northern limits. About 95% of the 

Firth is less than 30 metres deep. 

The Firth of Thames is the primary receiving environment for the ~3600 km 2 Hauraki 

Catchment. The inner half of the Firth (south of a line drawn between Tararu in the east and 

Kaiaua in the west) is very shallow (Figure 8-1), with a maximum depth of five metres 

(mainly in the middle) at mean low water spring tides (MLWS). For nearly all of the coastal 

area covered by the Ramsar designation, the intertidal zone is between one and two 

kilometres wide, with no more than a 1.5m change in altitude between its inner and outer 

margins. 

EcoQuest Education Foundation EQRS/1 12/04

Figure 1-1 Southern Hauraki Gulf and the Firth of Thames. The Ramsar Site sits between the 

low tide mark and the coast, extending from the Waihou River to Kaiaua. The five political 

districts and two regions bordering the Firth are shown 


3

Figure 1-2 Aerial view of the eastern end of the Ramsar Site, showing the Waihou and Piako river mouths, the stopbanks, farmland and the band of coastal 

mangroves.

Wind and tidal currents cause a net retention of a great volume of sediments brought into the 

southern half of the Firth by rivers and streams. By one estimate, the basin is infilling at the 

average rate of 0.8-1.0 mm per year at the centre and 1.8-2.0 mm near shore, mainly from 

sediments brought in by the Waihou and Piako Rivers (Naish et al.1990) (see Figure 1-2). 

Distribution of the entrained sediments entering the Firth of Thames varies with the changing 

circulation systems that dominate the movement of its waters. The three major influences that 

control the circulation systems present in the Firth are the East Auckland Current, the M2 tide, 

and prevailing winds. Residual water movement from the tide is found to be almost zero, with 

weak ebb and flow currents in the upper Firth of less than 1cm/s. Wind induced currents have 

been modelled by Proctor and Greig (1989), and show clockwise and anticlockwise circular 

gyres throughout the water column within the Firth of Thames. The East Auckland Current 

(flowing south-easterly from North Cape past Great Barrier Island), and the north-westerly 

winds of El Nin�o both act as partial barriers to the movement of sediments out of the Firth of 

Thames, resulting in deposition and accretion in the Firth itself and particularly along its 

southern and western margins (van Leeuwe 1991) (map, Figure 8-1). 

The mean annual air temperature is about 13ºC, and the average annual rainfall approx. 

1,200mm (Young and Harvey, 1996). Surface temperatures in the open waters of the Firth 

range from 14 o C. to 24 o C. in a “warm” year, 11 o C. to 22 o C. in a “cold” year (depending on 

the phase of the El Nin�o cycle) and there is usually less than one degree difference between 

top and bottom temperatures in depths of 10-12 m off Waimangu Point (M. Aislabie, pers. 

comm.). 

The Hauraki Catchment is a significant source of nutrients for the fertile waters and mudflats 

of the entire Hauraki Gulf, though the up welling of deep ocean waters at the north-eastern 

margin of the Gulf is by far the greatest source of nutrient supply, particularly when the northwesterly 

winds of El Niño blow consistently along the coast (Zeldis et al., 2000). The high 

plankton productivity resulting from these elevated levels of deep-water nutrients (along with 

those coming in as runoff from the catchment, and the decomposition of detritus mainly in the 

mangroves) supports abundant fish and littoral invertebrate populations (especially shellfish) 

in the Firth of Thames. 

The Firth of Thames has been recognised since the early settlement of Hauraki Maori for its 

immense life-supporting capacities, and in more recent times for its unique conservation and 

wildlife habitat values. It is still an important shared resource for various iwi, as well as non- 

Maori local residents and visitors. Two species of flounder are the foundation of a small local 

commercial fishery. Recreational fishing – based mainly on snapper (Pagrus auratus), 

kahawai (Arripis trutta), flounder (Rhombosolea leporina and R. plebeia) and trevally 

(Pseudocaranx dentex) – yields consistently good results. Shellfish farming, particularly 

greenshell mussels (Perna canaliculus), has expanded on both sides of the Firth and to the 

north at Waiheke and Great Barrier Islands. 

The Firth of Thames shoreline is scenically attractive. The road follows the coastline, giving 

excellent views of the Firth and the Coromandel Ranges. South of Kaiaua the shell banks 

present a spectacular sight, particularly in fine weather when their brilliant white reflects the 

sunlight. This natural beauty makes the Firth an important recreational resource for 

swimming, boating, fishing, shellfish gathering, camping, tramping, and horse riding (Bacon, 

1973). The number of casual visitors to the coast, especially during the summer months, is 

increasing rapidly. The Shorebird Centre of the Miranda Naturalists’ Trust provides for local 

bird-watching and environmental education activities. The Miranda Hot Springs and attached 

holiday park have become a major attraction for visitors to the area, as well as the locals. 


5

6 

Figure 1-3 Aerial composite of the Firth of Thames, with a close-up of one point along the stop 

bank near the Piako River mouth. 


Figure 1-4 continued. 


7

8 

The Firth’s geographical position makes it vulnerable to changes induced by natural events 

and human developments. The extent of impact arising from such events has, over the years, 

attracted considerable attention from numerous scientists and amateur naturalists. Land use in 

the catchment is predominantly agricultural, and recent years have seen intensified agriculture 

on the Hauraki Plains, accelerated growth of the Auckland and Waikato Regions, and the 

establishment of the Pacific Coast Highway around the perimeter of the Firth of Thames. This 

has resulted in ever increasing pressure on the environmental quality of this ecosystem. The 

Firth’s role as the receiving environment for the run-off from most of these areas also makes 

it a potentially very important site for monitoring of critical environmental indicators 

(Ministry for the Environment, 1997). 

1.4 Catchment 

The Firth receives freshwater influence directly from two main rivers: the Waihou and the 

Piako (Figures 1-2 and 1-3), the smaller Waitakaruru River, the Miranda Stream, Karito 

Canal, and a few lesser streams and drains in the west. The Waihou catchment extends back 

as far as Putaruru and together with the Piako drains nearly all of the Hauraki Plains. 

Historically this was covered with a vast kahikatea forest but is now developed for farming 

and a small amount of forestry. Within Hauraki District 67% of land is in primary 

production. The Waihou and Piako together contribute most of the sediments and nutrients 

that run off the land into the Firth of Thames. Much of the remainder of the catchment in 

Hauraki District lies within the Kopuatai peat dome - itself a Ramsar site and a major 

component of the Hauraki Plains Flood Control Scheme. There are also other small areas of 

peat bog and kahikatea forest under conservation management in the Waihou and Piako 

catchments. 

The wider Firth of Thames receives freshwater runoff from the Hunua and Coromandel 

Ranges - both largely vegetated in indigenous forest. Much of the Hunua water is diverted 

into large water supply dams serving Auckland, but flood flows from Coromandel rivers (in 

particular from the Kauaeranga, Te Puru, Waiomu, Tapu and Te Mata Rivers) can have a 

strong (if temporary) influence contributing to flooding of coastal settlements and sediment 

loading in the Firth. 

1.5 The Firth of Thames Ramsar Site 

The Firth of Thames Ramsar Site is comprised of intertidal area of the southern and western 

shores of the Firth of Thames between the west bank of the Waihou River and Kaiaua (Figure 

1-1and Figure 1-3). The intertidal area is defined by the extremes of mean low water spring 

tides (MLWS), and mean high water springs (MHWS), and covers about 8,500 ha (Veitch & 

Habraken, 1999). The vast, open inter-tidal mudflats, the mangrove communities that now 

cover much of the upper reaches of the intertidal zone, and the terrestrial areas adjacent to the 

mudflats are built on varying proportions of marine and land-derived sediments, old shell 

banks and vegetative debris. 

The graded shell banks of the coast between Miranda and Whakatiwai (Figure 1-1, Figure 6-3 

and Figure 9-2) are mainly derived from an active Chenier Plain, gradually pushed up on the 

shores by northeasterly storms and high tides. The Miranda Chenier Plain (course sediment 

and/or shell banks over-laying finer sediments) is unique in New Zealand, and one of the 

world’s finest examples of this rare coastal landform (Woodroffe, et al, 1983). A series of 

true Chenier ridges exist on the stretch of foreshore between Miranda and Kaiaua on the west 

coast of the Firth. This site has been the focus for a number of national and international 


studies, some of which use the Chenier Plains to determine the timings and extent of past sea 

level changes. 

The most recognised conservation feature of the Firth of Thames Ramsar Site is that it is a 

major stopover and over-wintering area for migrating water birds on the Australasian Flyway. 

The expansive wetlands and mudflats provide feeding and loafing grounds for over 80 

different species of shorebirds and water birds. Of these, 49 are migratory (12 indigenous 

species and 37 international migrants) including several rare and endangered species 

(Galbraith, 1992). These have been documented by various avian researchers (R.B. Sibson, 

R. Hay, N. Macdonald, H.R. McKenzie, and C.R. Veitch) over the years and have been under 

the close watch of the Miranda Naturalists’ Trust since 1973. 

The Ramsar Site also supports an extremely successful mangrove forest, mudflat invertebrate 

communities and salt marsh vegetation communities, constituting a vulnerable estuarine 

ecosystem that has settled into a new state of naturalness (though considerably different today 

from what it was prior to human settlement). 

The Ramsar Site is Crown land, managed by the Department of Conservation (DoC). The 

majority of the land adjoining the Ramsar Site is in private ownership, and much of it is 

grazed, to the benefit of the birds that use the area for roosting. A small, but significant area 

(27.7 ha) is covenanted under the Queen Elizabeth II Trust, and is managed jointly by the 

landowners and the Miranda Naturalists’ Trust. Also there is the 30 ha. Taramaire Coastal 

Reserve (managed by DoC), and a smaller one managed by Franklin District Council. In early 

2003 a consortium of conservation entities led by the Nature Heritage Fund, the Miranda 

Naturalists’ Trust and Environment Waikato achieved the purchase of 11 hectares of pastoral 

land near the Miranda Shorebird Centre for protection as a prime roosting area for waders. 

Some of the remaining private land at Miranda is designated for purchase by the Crown on a 

willing-seller basis. 

The Firth of Thames Ramsar Site has no status at all under the Conservation Act, the 

Reserves Act or the RMA. It does fall under the general protective measures of the Hauraki 

Gulf Marine Park, but this has proven (in the nearly five years since the inception of the 

HGMPA) to be one of New Zealand’s weakest conservation policy tools. 

1.6 Brief History of Hauraki Plains Reclamation Works and 

Drainage 

1.6.1 Maori settlement and influences on the sea and the land 

Tikapa Moana (Firth of Thames) is a central component of the Hauraki tribal territory. 

Historically Hauraki Maori lived predominantly on the fertile lowlands along the coast or 

waterways, which provided food resources and transport routes. It is possible that the 

shoreline and the seabed of the Firth of Thames today are superficially similar to that of pre- 

European times (Hauraki Maori Trust Board 1999). 

During the period of earliest Maori occupation in New Zealand (approximately 1000 years 

ago) the river courses were very different from what they are today. Phillips (2000) noted 

that settlements from the early period have not been found along the Waihou, and it is 

unknown whether Maori actually lived on the Hauraki Plains at this time, although they could 

well have used the resources. During the time of early settlement, the Waihou River provided 

only limited numbers of places favourable for Maori occupation or cultivation. 

The main effect of Maori occupation on the landscape of the Hauraki Plains was the clearance 

of the forest along the river and stream banks. Maori also cleared some of the hill country, 


9

10 

which probably resulted in erosion and an increased sediment load in rivers (Phillips 2000). 

Inter-tribal wars, land sales and European development all contributed to a re-orientation of 

lifestyle in the 1800s, and along with this a new Hauraki social order emerged (Hauraki Maori 

Trust Board 1999). 

1.6.2 Hauraki Plains at time of first European explorers and settlers 

At the time of first contact between Maori and Europeans, much of the land between the river 

and the foothills, on the eastern bank of the Waihou River, was cleared. A narrow strip of 

land along the western bank of the Waihou River (100-600 m wide) was cleared. Kahikatea 

(Dacrycarpus dacrydioides) forest was dominant. On both sides of the river there were large 

areas of raupo (Typha orientalis) and flax (Phormium tenax) swamp (Phillips 2000). The 

extensive coastal plains of the southern Firth of Thames (of which the current Ramsar Site 

occupies a small fraction) were recognized by Captain Cook and Joseph Banks in 1769 as “a 

garden and a pasture in which the best elements of British society might grow into an ideal 

nation”, in spite of being blanketed at the time by a vast Kahikatea forest containing the 

biggest trees they had ever seen (Park 1995). 

Cook and Banks (Beaglehole 1955 and 1963) also commented on the swamps and mangroves 

at the river mouth, and the mudflats and mangroves appeared on the early maps by Captain 

Cook and Captain Wilson (Phillips 2000). 

Cook and Banks considered the “Thames” (Waihou) River to be the best site for the 

establishment of a new colony (in terms of protected anchorage, fertile soil, huge expanse of 

flat land, vast quantities of fine timber and abundant fishery resources). 

An area of approximately 200,000 acres constituting the Hauraki Plains, originally known to 

Europeans as the Piako Swamp, was historically prone to regular flooding, and thus limited 

the possibilities for human habitation. All of the Maori settlements of the extensive Waihou 

and Piako river systems were on the highest bits of ground (including old raised shorelines) to 

minimize the risks of flooding, and for defensive purposes (Phillips 2000, Park 1995). 

Several early accounts mention that the lower reaches of the trees of the forest were 

perpetually clothed with films of mud and hanging debris from regular washings by the siltladen 

tides and floods. The early people grew vegetables in small plots of rich alluvial soil, 

fished, hunted, gathered shellfish from the water and collected fruits (particularly Kahikatea 

berries) and flax and raupo reeds from the land (Hauraki Maori Trust Board 1999). 

1.6.3 European settlement 

The swamp-growing Kahikatea proved unsuitable for the timber trade, but it still was 

extensively harvested for various uses (such as butter boxes) in the 2 nd half of the 19 th century. 

Most of the kahikatea used in that era was milled on the banks of the Waihou. The great 

expanses of flax and raupo swamp were highly valued by Maori as a source of fibre for 

clothing, cordage and roofing (Phillips 2000). Flax was also used by the European colonists 

who built many mills on the plains for processing it. 

Dairy farming was initiated on a very small scale by the early colonists on the west bank of 

the Waihou in the 1880s. The cream was churned into butter at home, and the skim milk fed 

to fattening pigs. Extensive drainage of the Hauraki Plains has been undertaken since early 

settlement. Some of the drains were cut by the first farmers in the 19th century, and drainage 

works as well as flood protection works continue up to the present day (Phillips 2000). 

The first organized land surveys and initial drainage efforts began in 1905, the same year the 

first creamery was established at Netherton. The Hauraki Plains Act was passed in 1908, 


providing for the drainage and settlement of up to 90,000 acres of what had become Crown 

land through “compulsory acquisition” from the Maori inhabitants, with a total of 160,000 

acres targeted for future benefits from the scheme (Tye, 1974). The Act provided for: 

• Improvements to the Piako River 

• Construction of the Maukoro Canal for drainage of the south-western region of the 

Plains (between the present Waitakaruru and Tahuna) 

• Construction of stop banks along the foreshore of the Firth and the Piako River to 

prevent tidal and flood overflows 

• An internal drainage system with floodgates 

• Construction of roads, bridges and wharves. 

The first land ballots were held in Thames in 1910, and 5,200 acres of surveyed, drained and 

burnt land was made available in 1911 for settlement by European farmers along the 

foreshore of the Firth between Waitakaruru and the Piako, and for 10 miles up the western 

bank of the Piako (Tye, 1974, Park, 1995). The first flood protection works began after the 

floods of 1907 and 1910 (Phillips 2000). 

The Waihou and Ohinemuri Rivers Act was passed in 1910, and drainage works of the 

Waihou and Ohinemuri River Improvement Scheme commenced in 1914 (Tye, 1974). 

Between 1913 and 1919 a stop bank was built along both sides of the Waihou and the lower 

Ohinemuri, as well as around the coast. By then, the great quantities of sludge released over 

the years by gold mining in the Ohinemuri Catchment had become a major contributor to the 

considerable build-up of sediments in the Waihou and the Firth itself (Tye, 1974). 

By 1920, 40,000 acres of Crown land had been settled, and there were 15 major wharves on 

the Piako alone that serviced the needs of the new farmers (Tye, 1974). The total 

transformation of the Piako Swamp was complete by the mid-1930s, after 25 years of major 

engineering works involving all sorts of mechanical dredges and barges, horse scoops and 

armies of labourers. Major alterations to the coastal and estuarine ecosystems were already 

underway. When all waterways were channelled and floodgated, and great stop bank barriers 

built, natural floodplain sediment absorption processes were virtually eliminated. 

These initiatives soon proved to be inadequate. Two new schemes were subsequently devised 

to assist natural drainage and to alleviate the serious flooding that continued to occur 

(especially in 1952-53 and 1960-61). Works on the Piako River Scheme commenced in 1961, 

and were completed in 1974. Following more disastrous floods in 1977, the Waihou Valley 

Scheme was formulated. This involved raising and realigning stop banks, straightening 

streams and cutting toe drains on the landward side of the stop bank, and in some areas the 

creation of floodways (Phillips 2000). The Waihou Valley Scheme works were completed in 

the early 1980s. 

Tye (1974) estimated that 17,500,000 cubic yards of earth were shifted during the combined 

works on the Waihou and Piako systems, and that there were 319 miles of channels; 255 

miles of stop banks, 155 floodgated culverts, and 50 pump stations. 

The straightening and banking of the Karito Canal was carried out in the 1930s. 

Construction of the stopbank along the 4 km stretch between the Canal and Waitakaruru 

began in 1945. Work on the approximately 2.5 km stopbank north from the Canal to the 

Miranda Hot Springs Drain began once the link with the Plains schemes at the Maukoro 

Canal (Waitakaruru) was completed. From the Hot Springs Drain north to Kaiaua, the coast 


11

12 

road has served as a low “stopbank”, with some natural assistance from the inland Chenier 

shell ridges, and the numerous banks built by farmers over the years with spoils from the 

dredging of drains. The original road was built with great quantities of shell from the Chenier 

ridges, which, together with the Miranda Limeworks that operated between 1932 and 1952, 

significantly changed the landscape of the Chenier Plain. 

Continuing heavy sediment loads building up in the catchments, compounded by periodic 

intensive storms (of particular note in recent times: the storms of 1981, 1987, 1993, 1995, 

1997) require regular maintenance dredging of the drainage canals. The Pouarua Canal 

sustained regular clogging from peat mining in the area, but the mining has now finished. 

The stop banks sustain breaches at low points during some extremes of wind, tide and rain, 

particularly in combination with very low barometric pressure. In most parts of the system the 

stop banks are slowly getting lower, settling into the old sediments under them. 

In the period 2002 to 2004, the heights of various sections of stop bank were increased, 

especially from the Maukoro Canal to the Hot Springs (including a short extension northward 

from the Hot Springs Drain). This was done by dredging a channel along the outer edge of 

the stopbank and depositing the spoils on top of the existing bank (or on the new ground to 

serve as a foundation for further bank development once the spoils stabilise. 

Dredging is a permitted activity, under the planning and supervision of the Waikato Regional 

Council and/or the Hauraki District Council. It and has typically been performed on a 3-6 

year cycle, as required, on most drains and canals in the system ever since the first major 

schemes were completed in the 1930s. 

The need for maintenance dredging is increasing throughout Hauraki District and parts of 

Matamata-Piako, Thames Coromandel and Waikato Districts. As an example, until 3 years 

ago dredging was performed only as far inland as Ngatea, on a bi-annual basis, and now it is 

required as far upstream as Patetonga, with a frequency of 1-3 times per year (Steve Clark, 

personal communication 2004). 

The bars outside the mouths of the Waihou, Piako and Waitakaruru Rivers are another 

indication of increasing sedimentation in the Upper Firth. These have always been in a state 

of flux, and of variable size and location. All three bars showed an increasing tendency by 

late 2004 to become larger and less variable, causing greater restrictions of the water flows 

out of the rivers, and contributing to the more permanent establishment of mangroves around 

them. 


2 Hydrology 

by Ria Brejaart, Bill Brownell and Rebecca Cheatley 

2.1 Hauraki sediments 

The Hauraki Plains and adjacent ranges had their origins in the early Miocene, approximately 

20 million years ago, which marked a time of great upheaval. In this period a rift valley 

developed in the Hauraki area. The Hauraki Rift is 25 km wide and 200 km long, and extends 

from the Hauraki Gulf in the north, through the Firth of Thames and the Hauraki Plains south 

into the Matamata lowlands. Within the Hauraki Rift are two depressions, separated by a 

median ridge (Phillips 2000, Hochstein & Nixon 1979). The rift is still active, and at least 5 

earthquakes in the last 9000 years have resulted in the subsidence of the western depression 

by a total of 2.1m. The western Hunua and Hapuakohe ranges, which reach a height of 500 

m, are of a predominantly sedimentary formation. In contrast to the subsidence of the 

Hauraki rift, the Hunua Ranges have been rising at approximately 10 cm every 1000 years. 

The eastern ranges (the Coromandel and Kaimai ranges) are of predominantly volcanic 

origins. They form steep hill country rising to 800 m above the eastern margin of the Hauraki 

Plains (Phillips 2000). 

Geographically, the Firth of Thames occupies the northern part of the Hauraki rift. 

Quaternary and Tertiary sediments that fill the geologic depressions in the Firth reach a 

maximum thickness of about 3 km (Grieg 1982). Most of the sub-tidal floor in the 

embayment is overlain by fine clay, green-grey silts and sand sediments, derived 

predominantly from the rivers (Hochstein & Nixon 1979). 

For the last 20,000 years the Waihou River has flowed down the Hauraki Plains. Although 

changing course from time to time, the river has kept mostly to the eastern depression 

(Phillips 2000). The coastline has also altered significantly, as evidenced by the old coastal 

beach ridges which are now far inland (Phillips 2000). Phillips (2000) documented deposits 

of subfossil shell and former shorelines on the Hauraki Plains. She suggested that the 

sediments deposited between the shorelines identified as those from 6500 and 1250 years ago, 

consist principally of ash (brought down by the rivers) from the Taupo eruption of 1850 years 

ago. The sediments between the shorelines of 1250 and 200 years ago principally contain 

Kaharoa ash that erupted from Mt Tarawera some 600 years ago. 

Extensive land clearance following European settlement has resulted in an increase in 

sedimentation throughout New Zealand. Major sediment inputs into the Firth of Thames are 

from the Kauaeranga, Waihou, Piako and Waitakaruru rivers, which drain the Kaimai Range 

and the Hauraki Plains. Additional inputs come from the smaller streams draining the Hunua 

Ranges to the west, and the Coromandel Range to the east (Phillips 2000, Scott 1995). 

The sheer volume of sediment brought down by the Waihou River alone is illustrated by 

Phillips (2000). She documented the silting up of the eastern channel around Tuitahi Island 

(in the northern reaches of the Waihou River): “In 1769 the depth of the channel was 

reported to be 2 fathoms (3.6 m); in 1794 it was still the main channel; soon after 1830 it was 

no longer navigable; by 1873 only the northern section was partly open and this too has now 

become silted up. It is estimated that a total of 2 million cubic metres of silt must have been 

deposited to account for the difference between the depth of the channel in 1769 and its 

present level”. 


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14 

Griffiths and Glasby (1985) estimated the annual contribution of sediment volume from the 

Waihou River to the open ocean (based on a sediment yield of 174 tonnes/km 2 /yr from a 

basin area of 1969 km 2 ) to be 343 000 tonnes per year (66 % of the total contribution of the 

Firth of Thames Catchment). The second largest sediment input to the ocean (82 000 tonnes 

per year) comes from the Piako River (15%). The Coromandel Coast contributes 8%, and the 

Miranda Coast, 7%. The Waitakaruru River makes up the remaining 4%. 

2.1.1 Impact of Land Use 

The predominant land use of the coastal marginal strip of the western shores of the Firth of 

Thames is dairy farming, where in some cases stock graze below the high tide mark with the 

possibility that the land use practices may have a detrimental effect on the ecology of the 

coastal margin. Two surveys of the shallow groundwater geochemistry and nutrient processes 

of the coastal marginal strip have been undertaken. 

Analysis conducted by Bryce (1997) of the shallow groundwaters at Miranda revealed high 

nutrient levels draining into adjacent salt marsh and mangrove systems. The flora in these 

environments typically survives with low nutrient inputs (Bryce 1997). 

Farm management practices, local hydrology and substrate type were important determinants 

in the level of groundwater contamination by nutrients (Cheatley 2000). Cheatley sampled 

the groundwater at both grazed and non-grazed sites at Miranda and found 1) that the 

concentrations of nitrogen and phosphorus in groundwater for grazed sites were greater than 

those of non-grazed sites and 2) that the rate of fertilizer applications was a determinant in the 

concentrations. Both nutrients are ineffectively used by dairy cattle, with the majority of the 

nitrate and phosphate ingested being excreted as urine and faeces. 

High levels of nutrients, especially nitrates, may alter the growth patterns of the local flora 

(Bryce 1997). Leaching of nutrients was enhanced at the Firth of Thames, due to the high 

water table and the porous substrate (shell layers). As the direction of groundwater flow is 

toward the sea, the high concentrations of nutrients are eventually transported into the Firth of 

Thames (Cheatley 2000). 

Cheatley (2000) recommended that excess use of nitrogen and phosphorous (in the form of 

fertilizer) close to the estuarine marginal strip should be avoided, since the application of 

fertilizer has greatly influenced the concentrations of nutrients in the coastal ground waters. 

Vant (1999) calculated average mass flows of nitrogen and phosphorus in Hauraki rivers 

during 1993-1997. He then did comparative calculations for the period 1998-2002 (B. Vant 

personal communication 2004). The following summary shows that all values have decreased 

over that time period, most of them significantly. This could be a result of improved farm 

management practices in the Waikato Region in recent years: 

Location Nitrogen (g/s) Phosphorus (g/s) 

93-97 98-02 93-97 98-02 

Piako @ Paeroa-Tahuna Rd. 32.8 22.5 2.55 2.02 

Waitoa @ Mellon Rd. 22.6 15.3 6.34 2.50 

Waihou @ Okauia 38.1 32.5 3.41 2.55 

Waihou @ Te Aroha 52.7 50.5 4.36 4.05 

Ohinemuri @ Karangahake 10.4 6.4 0.81 0.18 


2.2 Summary of Cheatley (2000) 

Ground water samples were collected at six weekly intervals (April to November 1999) from 

six sampling sites spanning the coastline of the Firth of Thames. Of the six sites, three grazed 

sites were compared to three non-grazed sites to establish the relationship between land use 

and shallow ground water geochemistry. At each site a number of shallow bores were 

installed. Geochemical processes in ground waters were determined by analysing 

concentrations of major anions and cations and the abundance of the stable isotopes of 

carbon. 

Porous shell layers with an abundance of organic matter and a high water table generate 

anaerobic conditions which govern the concentrations of constituents found in ground waters 

at the Firth of Thames. The geochemical processes which dominated this estuarine 

environment were; mixing of sea water with ground water, weathering reactions, 

oxidation/reduction mechanisms, chemical precipitation, ion exchange reactions and the input 

of fertiliser. 

Seawater provided the dominant source of chloride, sodium, boron and magnesium resulting 

in constant ratios of the conservative elements as they were diluted with rain derived ground 

water. Carbonate dissolution was the dominant weathering reaction in sample waters 

resulting in increased concentrations of calcium, bicarbonate, and a decrease in the ratio of 

strontium to calcium in ground waters. The concentrations of zinc, aluminium and silica were 

enriched relative to seawater as a result of the weathering of parent rock material, 

predominantly silicate minerals. 

Sulphate reducing bacteria were identified and the products of sulphate reduction (sulphides, 

mercaptans, loss of sulphate), were apparent from the analysis of the ground waters. 

Although reducing conditions were such that ferric iron would have been reduced to ferrous, 

this species was unable to become a major ionic component of the ground water solutions due 

to the precipitation of iron sulphides. However, with pH values of 7.5 to 8 the stable form of 

manganese is Mn 2+ , resulting in mobilisation of manganese and reprecipitation of iron. 

Ground waters with Mn 2+ /Fe 2+ ratios as high as 5 were observed in Firth of Thames ground 

waters. On discharge to surface waters these solutions will be oxidised forcing the 

precipitation of ferric and manganese oxides. Elevated concentrations of potassium in sample 

waters were attributed to ion exchange reactions driven by the high concentrations of 

(strongly absorbed) divalent cations such as calcium derived from the dissolution of shell 

carbonate. 

The isotopic composition of ground waters is a reflection of their history. The δ 13 C values of 

the DIC (-10‰ to -15‰) reflected values typical for those derived by soil atmosphere (-25‰) 

with a major contribution from the dissolution of calcium carbonate(-1‰ to +2‰). Two of 

the reducing grazed sites showed enrichment in 13 C (+1‰ to +5‰) with the most likely cause 

being methanogenesis. 

Farm management practices influenced the concentrations of nitrate, ammonia and phosphate 

in ground waters. Concentrations of nitrogen and phosphorus in ground water for grazed sites 

were greater (P

16 

were not observed at sampling sites. The concentration of phosphorus was highly elevated in 

ground water. The potential sources for phosphate in ground waters were complex. Most of 

the nutrients originated as fertilisers applied to intensely grazed pasture, but high populations 

of roosting birds were also likely to contribute to the high concentrations of nutrients 

(particularly phosphorus) leached into the coastal margin of the Firth of Thames. A 

comparison between grazed versus non grazed sites indicates that the contribution from birds 

is of minor significance to fertiliser input at Firth of Thames sampling sites. As the direction 

of ground water flow is towards the sea, the high concentrations of nutrients will eventually 

be transported into the Firth of Thames estuary which has been designated an area of 

international significance. 


3 Vegetation 

by Peter Maddison and Ria Brejaart 

(with contributions by Bill Brownell, John Longden, Patrick Stewart and Bec Stanley) 

The vegetation of the coastal zone of the Miranda-Kaiaua area has recently been the subject 

of in-depth research (Merrett & Clarkson, 1997, and Strahan, 1997), and this research has 

been summarized in detail in 3.1 below. 

For the purpose of this study, a pilot survey of the foreshore vegetation of the southern part of 

the Firth of Thames (Tararu to Hot Springs Drain) was carried out in 1998 and 1999. The 

findings of this are described in 3.2. 

3.1 Miranda – Kaiaua foreshore 

The Miranda-Kaiaua Coast is typically an area of deposition and accretion. It is best known 

for its large shell banks and Chenier plain. The extensive boulder beaches north of Kaiaua are 

a less spectacular, but equally significant geological feature of the area. 

Compared with the relatively large body of literature on the birds of the Miranda coast, there 

has been little work done on the vegetation of the area. Bacon (1973) summarised the 

vegetation types of the area from Kawakawa Bay to Miranda and Morton (1983) produced 

“The shore and salt marsh plants of Miranda” (Miranda Nature Notes No.1). The foreshore 

area was surveyed and the vegetation mapped in 1997 by the Waikato Botanical Society 

(Merrett & Clarkson 1997). In the same year, Strahan (1997) completed his thesis for Master 

of Science in Biology at the University of Waikato titled “The plant ecology of Miranda 

Wetland: restoration options”. Since 1999 a number of vegetation studies of this coastal area 

have been made by students at EcoQuest. Our own observations from initial investigations 

are also included here. 

A summary of plant species found at Miranda is presented in Appendix 3.1. Analysis of these 

records shows the prevalence of exotic species: 

Native 34 20.1% 

Native (planted) 4 2.3% 

Exotic weeds + plants 133 78.6% 

Doubtful records 2 ( not included in total) 

TOTAL 169 

Merrett & Clarkson (1997) recognized seven distinct communities: 

1. Mangrove (Avicennia marina var. australasica [= resinifera]) 

2. Young shell banks (with sparse introduced herbs) 

3. Glasswort Salt Marsh (Sarcocornia) 

4. Bachelor’s Button (Cotula) – Maori Musk (Mimulus) area 

5. Sedge (Carex divisa – introduced) areas 

6. Ryegrass (Lolium) – Bur Medic (Medicago) short grassland 

7. Salt marsh Ribbonwood (Plagianthus divaricatus) – Mingimingi (Coprosma) shrub 


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3.1.1 Mangrove 

The mangrove dominates situations with muddy substrates that are subject to tidal inundation, 

particularly along streamsides and nearby mudflats. The dredged drainage channels that are 

subject to tidal inundation are also colonised. Few other vascular plants occur amongst the 

mangroves but in slightly better drained mangrove sites salt marsh ribbonwood may occur. 

Aerial photographs also show that slightly raised, cleared areas amongst the mangrove may 

be invaded by Spartina grass (Thomson 2000). 

There are a number of management issues associated with mangroves throughout the Ramsar 

Site, particularly along the Miranda – Kaiaua Coast. North of the Miranda Stream mangrove 

zones are now established along the stream channels and coastal lagoons, with occasional 

small patches in the coastal mud. Chapter 4 addresses mangroves in detail. 

In summary, mangroves provide several valuable functions:- 

• Consolidation of muddy foreshore areas, resulting in less erosion and protecting 

coastal areas from wave and some storm damage. (Note: Powerful storms of rare 

occurrence can erode the coast and wash away whole plants.) 

• Because of the stability of the mangrove habitat and the number of stems and 

pneumatophores for animals and plants to settle on, these areas provide protected 

habitats for invertebrates and fish, particularly for spawning. A food chain develops, 

the apex of which are predators such as fish and birds. 

• The shade provided by the mangrove trees prevents the mud drying out – a factor 

which can be important for the fauna, especially in prolonged periods of dry weather. 

3.1.2 Recent Shellbanks 

The large shell banks forming the spits into the sea and the eastern edge of the coastal Chenier 

plain are comparatively “young”. Plants colonising this habitat are generally ruderal weeds 

such as bur medick (Medicago nigra), pink bindweed (Calystegia sepium), viper’s bugloss 

(Echium vulgare), oxtongue (Picris echioides) and ribwort (Plantago lanceolata). Plants 

growing on these banks have to cope with exposure to desiccation from the wind and sun, and 

a lack of soil in the surface layer. Though most of these plants have wind-blown seeds, it is 

possible that some species may be dispersed by birds, as the shell spits and coastal meadows 

are favourite roosting places of the waders, and nesting sites of at least three bird species. On 

this western shore of the Firth these shell banks may abut salt marsh wetlands and grade into 

more weathered older shellbanks that have been modified by shell extraction and grazing of 

cattle. 

Other plants recorded colonising these areas are herb Robert (Geranium robertianum), beet 

(Beta vulgaris), stonecrop (Sedum acre), prickly sowthistle (Sonchus asper) and grasses such 

as Lolium perenne, Bromus diandrus, B. hordeaceus and Parapholis incurva. Occasional 

Scotch thistle (Cirsium arvense) with large taproots are found on these shellbanks. 

3.1.3 Glasswort Salt Marsh 

Salt marshes are generally located in the intertidal zone. They are flooded by the high tide 

and are exposed at low tide. Mitsch & Gosselink (1993) defined two broad categories of salt 

marshes as those formed from reworked marine sediments, and those formed by river 

sediments in deltaic areas. The salt marshes along the Miranda-Kaiaua coastline are marine 

dominated marshes. Salt marshes depend on a sufficient rate of sedimentation and avoidance 

of areas of coastal erosion. In the Miranda area, coastal erosion is avoided due to the band of 


mangroves positioned between the marsh and the estuary. This particular habitat is further 

sheltered by the outer shellbanks, which form a protective lee. The chemistry of the salt 

marsh system (salinity, nutrient availability and anaerobic status) determines the type of 

vegetation (Bryce 1998). 

Glasswort (Sarcocornia quinqueflora) forms extensive areas of salt marsh or ‘salt meadow’, 

west of the seaward shellbank. Sarcocornia has a high salt tolerance and can live on mudflats 

that are submerged with each tide. Besides its singular occurrence close to the shoreline, it 

was also present in association with other plants in the muddy brackish water hollows and 

drainage channels inshore from the stop banks. 

Four types of assemblage were recognised by Merrett and Clarkson (1997): 

• Sarcocornia – Sea blite (Suaeda novae-zelandiae) 

In muddy hollows, etc. Also with Spergularia media and curved sea hard-grass (Parapholis 

incurva). 

• Sarcocornia – Sea primrose (Samolus repens) 

Other species associated were Carex divisa (frequent), small salt marsh ribbonwood, plantains 

(Plantago coronopus and P. lanceolatus), the creeping Selliera radicans, the grass Stipa 

stipoides and arrow-grass, Triglochin striata. 

• Selliera radicans – Sea primrose (Samolus repens) 

Small communities of these two plants were present in wet muddy substrates in parts of the 

salt marsh. The presence of Selliera generally indicates some freshwater seepage. 

Sometimes the rush, Juncus kraussii var. australiensis and straggling stems of glasswort were 

present. Merrett and Clarkson (1997) indicated that this vegetation type was found in one 

area which formerly supported mangrove forest. 

• Curved sea hard-grass (Parapholis incurva) – Plantago coronopus 

This type of vegetation was often present around the edges of the salt marsh on drier shellmud 

substrates – also possibly associated with trampling by cattle. This area was generally 

transitional from salt marsh to well-drained areas of the older Chenier shellbanks. Other 

plants recorded were glasswort, sea primrose, bur medick (Medicago nigra) and grasses 

(Bromus diandrus and Cynodon dactylon). This type of salt marsh is very susceptible to 

trampling by cattle (and humans). Some well-formed tracks may be seen across these areas. 

3.1.4 Bachelor’s Button (Cotula) – Maori Musk (Mimulus) area 

A distinct community of bachelor’s button and Maori musk is found in small, isolated areas 

of wet mud, usually in hollows, depressions or the sides of small ditches. Mimulus grows on 

wetter sites, whereas Cotula is found on both wet and dry mud. Other plants were sea 

primrose (Samolus) and Bolboschoenus caldwellii. In the transition area between this Cotula- 

Mimulus area and dryland sites, sea hard-grass (Parapholis strigosa) and tall fescue 

(Schedonurus phoenix) are frequently observed. [See separate section about Mimulus 

repens.] 

3.1.5 Sedge (Carex divisa) areas 

The introduced divided sedge (Carex invisa) is an important component of the vegetation at 

Miranda. It occurs in both wet and dry areas. 


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Wet Carex divisa 

This sedge may dominate the edge of the various water bodies, at times covering 70-90% of 

these areas, with occasional grasses (Cynodon, Schedonurus.) 

Dry Carex divisa 

Carex divisa forms scattered patches on dry shell-mud ridges. Other plants in this association 

are prickly sowthistle (Sonchus asper), tarweed (Parentucellia vicosa), buck’shorn plantain 

(Plantago coronopus) and perennial ryegrass (Lolium perenne). 

The impact of the introduced divided sedge (Carex invisa) on the salt marsh ecology was part 

of the study by Strahan (1997). Strahan studied the salinity tolerance of this sedge and the 

competition between this and other species in the salt marsh. [See section 3.3 Grazing.] 

3.1.6 Ryegrass (Lolium)– Bur Medic (Medicago) short grassland 

This grassland community is the most abundant over the old shellbanks of the Chenier plain 

at Miranda. It occurs on the drier shell/soil substrates, further from the sea but adjacent to the 

salt marsh and has the coastal highway going through it. The vegetation is more diverse than 

elsewhere but is dominated by introduced species, principally legumes and grasses. 

Important elements are sea primrose (Samolus), ox-tongue (Picris), stonecrop (Sedum acre), 

viper’s bugloss (Echium), chickweed (Stellaria), dove’s foot (Geranium), plantains 

(Plantago), divided sedge (Carex divisa), legumes (Medicago, Trifolium) and grasses (Briza, 

Bromus, Catapodium, Cynodon, Hordeum, Lolium, Parapholis, Pennisetum, Polypogon, 

Vulpia.) 

This is the main area grazed by cattle, which in wetter places is subject to trampling and 

pugging. It forms an important part of the Miranda area both for human access and as the 

habitat for several introduced birds such as the skylark, which nests in depressions in this 

grassland, and seed-eating birds, such as finches. 

3.1.7 Saltmarsh Ribbonwood (Plagianthus)– Mingimingi (Coprosma) shrub 

This association is only found in a few isolated areas at Miranda but more extensive areas are 

found in other parts of the Coast. The salt marsh ribbonwood is a common constituent of salt 

marsh and old shellbank vegetation throughout New Zealand. In an area near the Miranda 

Stream it is associated with planted tamarisk (Tamarix sp.), but there is also a small roadside 

community north of the Shorebird Centre, where it is associated with mingimingi (Coprosma 

propinqua) and pohuehue (Muehlenbeckia complexa). 

This latter community is also the site for the endangered green mistletoe (Ileostylus 

micranthus.) [See section 3.4 Threatened plants of Miranda] 

3.2 Survey of the foreshore between Tararu and Hot Springs Drain 

Pilot surveys of the foreshore vegetation of the southern part of the Firth of Thames (Tararu 

to Hot Springs Drain) were carried out in 1998 and 1999 (6 days total). The observers 

travelled mainly along the stop banks, on foot and by quad, from Tararu (north of Thames) to 

the Hot Springs Drain at Miranda, and along the beach from Taramaire to Kaiaua. Similar 

work was done by kayak in the Piako River, and from Waitakaruru to the Miranda Stream at 

high to mid tide. Observations were made for comparison with, and clarification of, colour 

aerial photographs (December 1996 series, Figure 1-2, Figure 1-3 and Figure -5-2) from 

Tararu to Kaiaua (Figure 1-1). General characteristics and predominant land uses are 

described for each of the sections surveyed. The main focus was on broad vegetation types 


and available habitat types for waders and shorebirds. Bird observations made during this 

survey are included in Chapter 5. 

3.2.1 Tararu Creek – Kopu Bridge (January, 1999) 

The starting point for this section was next to the mouth of the Tararu Stream, 2 km north of 

Thames. The west coast of Coromandel Peninsula is prone to erosion by wave action and 

flooding of the creeks and rivers, during and following storm events. Flat land between the 

Coromandel Range and the sea is minimal or absent, especially north of Thames. Generally, 

residential and commercial development comes right out to MHWS level along the foreshore 

of Tararu and most of Thames. South of the Kauaeranga River, the stopbank forms a barrier 

between the Waihou River/Firth of Thames and the low-lying land of the coastal zone. The 

Goldfields Mall and Moanataiari (a residential development at the northern end of Thames) 

are situated on reclaimed land, and protrude into the Firth beyond the shoreline. A seawall 

was constructed at Moanataiari in the early and mid 1990s and there is no exposed beachfront 

along here at high tide. At the mouth of the Kauaeranga River there are permanent moorings 

and a jetty. South of the Kauaeranga River, landuse in the coastal zone includes the airport, 

sewage treatment plant, residential development at Totara and commercial/industrial 

development at Kopu. 

Major vegetation types 

Extensive areas of mangroves occur from the west bank of the Waihou to Thames. Although 

increasingly sparse toward Tararu, mangroves were found along the entire foreshore area 

surveyed. They penetrate all creeks and rivers that flow into the Firth along this section of the 

Thames Coast. On either side of the Kauaeranga River, self-seeded Phoenix palms (Phoenix 

canariensis) were observed in the mangals. Between the Kauaeranga River and Kopu the 

mangroves are interspersed with patches of Sarcocornia quinqueflora, and kukuraho, or 

marsh clubrush (Bolboschoenus fluviatilis). A small planting adjacent to the mangroves 

includes pohutukawa (Metrosideros excelsa), ngaio (Myoporum laetum) and flax (Phormium 

tenax). 

The mangroves are tallest (2 m), and the area occupied by them is widest, between the 

Kauaeranga River and Kopu. Introduced grasses and weeds are present along most of the 

Thames foreshore, and they encroach on the beach and into the mangroves in many places. 

3.2.2 West bank of the Waihou River to Waitakaruru River – surveyed 

from the stopbank (September 1998) 

Land use behind the stopbank is agricultural. A canal (from the original dredging) runs 

parallel to the stopbank along the seaward side for most of this stretch. Stock has access to 

this strip in most places, as well as to some areas of salt marsh on the seaward side of the 

canal amongst the mangroves. 

The area immediately north of the Kopu Bridge (left bank of the Waihou River, heading 

toward the Firth) is characterised by a relatively narrow (10-40 m) strip of tall (2-3 m) 

mangroves. Immediately behind the mangroves is a wetland area (between the river and the 

stopbank canal) which is dominated by annual grasses and kukuraho. This continues for 

about 2-3 kilometres, and large patches of batchelor’s button are locally common. Coprosma 

propinqua and salt marsh ribbonwood are present as well. 

The area of mangroves at the mouth of the Waihou River is at least 500 metres wide, and 

access on foot into the mangroves was not possible due to the very soft mud in the canal and 

throughout the mangal. 


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Continuing west toward the Piako River, the vegetation between the mangal and the stopbank 

changes little, but Glasswort Salt Marsh becomes increasingly dominant. About five 

kilometres east of the Piako River, the salt marsh is about 500 metres wide. Closer to the 

Piako River, Sarcocornia is patchy, and kukuraho is present. Within one kilometre of the 

Piako River, Coprosma propinqua and C.x cunninghamii, salt marsh ribbonwood and 

kukuraho are common. At the mouth of the Piako, the mangal is narrow, but the mangroves 

are tall (up to 4 m). 

Dense and even aged stands of mangroves line the mouth of the Piako River. Beginning 

approximately four kilometres west of the Piako River on the fringes of the stopbank canal 

there is extensive mangrove recruitment. There are large areas of Sarcocornia salt marsh. 

Approximately five kilometres east of Waitakaruru there is considerable new growth of 

mangroves, an area browsed by stock in the mid-1990s). Kukuraho is established throughout 

the salt marsh close to the Waitakaruru River. Mud crabs (Helice crassa) and mud whelks 

were abundant. 


Extensive and near continuous mangals occur, up to 500 metres wide, at the mouth of the 

Waihou River. Mangroves near the Piako River are tall and occur in dense stands. 

The Glasswort Salt Marsh is dominated by Sarcocornia and interspersed with batchelor’s 

button and occasional salt marsh ribbonwood, Coprosma and pohuehue. Adventive species in 

this area include Cortaderia selloana and Scotch thistle (Cirsium vulgare). Although we did 

not see any Spartina, a subsequent aerial survey (Thomson, 2000) established that Spartina is 

present in the salt marsh. Phragmites australis and Paspalum distichum were also noted. 

3.2.3 Hot Springs Drain to Waitakaruru (November 1998) 

At the mouth of the Hot Springs Drain (on the western shore of the Firth, south of Miranda) 

considerable build up of shells was noted. The area is characterised by near-continuous 

mangroves, and extensive Sarcocornia salt marsh with dense swathes of bachelor's button. 

Kukuraho is present along with annuals and introduced grasses. Salt marsh ribbonwood is 

common in the vicinity of the Hot Springs Drain. Large areas of mangrove dieback were 

recorded adjacent to, and south of, the Karito Canal (see chapter 4). 


There is extensive and nearly continuous cover of mangals along this coast from the Miranda 

Stream south to the Waitakaruru River. Glasswort-dominated salt marsh is interspersed with 

batchelor’s button and salt marsh ribbonwood. Coprosma propinqua, C.x cunninghamii and 

pohuehue were present, but occasional. 

During an additional survey along the southern margin of the Karito Canal (26 July 2001) the 

following plants were found seaward of the stopbank floodgate: 

Family Juncaceae 

Juncus maritimus Lamarck var. australiensis Buchenau (Sea Rush) 

Family Poaceae 

*Agrostis stolonifera L. (Creeping Bent) 

*Polypogon monspeliensis (L.) Desf. (Beard Grass) 

*Schedonorus phoenix (Scop.) Holub (Tall Fescue) 

Family Polygonaceae 

Muehlenbeckia complexa (Cunningham) Meissner (Pohuehue) 


Family Asteraceae 

*Aster subulatus Michaux (Sea Aster) 

Family Chenopodiaceae 

*Atriplex patula L. (Orache) 

(* = introduced) 

3.3 Grazing 

The winter grazing of grassy patches within the coastal vegetation of the Miranda-Kaiaua 

foreshore has been a regular practice for many years. Signs of the effects of cattle grazing, 

such as paths worn by the cattle and deep pugging, are particularly obvious in those areas 

subject to waterlogging. Strahan (1997) studied the effects of grazing and compared these 

with the effects of mowing and herbicide control in the Miranda area. He concludes, 

“Leaving the salt marsh ungrazed to revert to its natural state is not possible due to well 

established exotics, poor native seed sources … and an altered hydrology”. A 2003 survey by 

EcoQuest students of the distribution of native and exotic species at the Miranda Reserve 

showed that in the grazed area, introduced species were dominant. In the salt marsh and 

mangrove areas, native species predominate (Peter Maddison, personal communication). 

Among the recommendations in Strahan’s thesis are: 

• Grazing should be maintained to stop Carex divisa from developing a closed canopy 

and reducing species diversity. 

• Protection of some of the larger salt-marsh communities by fencing to prevent 

trampling and pugging. 

• Work to help re-establish oioi (Apodasmia similis) [see 3.4] 

• Changing the hydrology by opening flapgates 

• Enhanced planting of Plagianthus, Muehlenbeckia and Coprosma at the sites near the 

Shorebird Centre, which will also serve to help the restoration of the mistletoe 

(Ileostylus). A number of these shrubs have been planted – Strahan recommended 

mowing around these shrubs until a dense canopy is achieved. [See 3.4 Threatened 

plants of Miranda] 

Strahan also suggested the establishment of long term plots to compare the effects of grazing 

and mowing with ungrazed areas and to monitor these plots over at least a five year period for 

changes in community composition. He advocates establishing a “restoration team” 

involving all the stakeholders involved. 

The restoration of the ecology of the Miranda area is further complicated by factors such as: 

• The ownership of the land and farming practices 

• The desires of the Miranda Naturalists’ Trust (= the birdwatchers) for maintenance of 

habitat suitable for the wader birds and other bird species 

• Public access to the area 

• Natural changes in the Chenier plain, particularly those caused by storm events 

• Incursion by mangrove seedlings and “new” weeds (e.g. Spartina) 

Elsewhere in the Ramsar area, considerable change in the coastal vegetation has occurred 

because of hydrological and other engineering works (drainage canals, stop banks, road 


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construction). The advance of the mangroves is recorded in Chapter 4. Both human 

interference and natural forces can be seen to have significant effects on the coastal 

vegetation of this area. 

3.4 Threatened plants of Miranda 

3.4.1 Pirita, Papauma, Green Mistletoe – Ileostylus micranthus 

Pirita occurs in a small roadside clump of trees north of the Shorebird Centre. There it 

parasitises salt marsh ribbonwood, Plagianthus divaricatus, mingimingi, Coprosma 

propinqua and pohuehue, Muehlenbeckia complexa. Pirita was formerly widespread 

throughout New Zealand but in many parts of its range this mistletoe has been substantially 

reduced, mainly through habitat loss and a reduction in the number of birds active in seed 

distribution (Rebecca Stanley, personal communication). Host plants also include species of 

Carmichaelia (native broom), other Coprosma, Hoheria (lacebark), Leptospermum (manuka), 

Leucopogon (mingimingi), Lophomyrtus (ramarama, etc.) and Podocarpus. It has also been 

recorded on introduced plants of the genera Crataegus (hawthorn), Cytisus (broom), Pinus 

(pine), Platanus (plane tree), Pyrus (pear) and Rosa (rose) (Allan 1982). Cameron (2000) 

lists the host species in the Kaiaua - Miranda area as being Plagianthus divaricatus, 

Muehlenbeckia australis, Cupressus macrocarpa, Ulex europea (gorse), and Coprosma 

propinqua. 

Pirita is currently classified as “Regionally Critical” (meaning

Though creeping musk is of widespread distribution in both North and South Islands, it is 

regarded as “Regionally Endangered” in the Auckland Region (Stanley 1998) and in the 

Waikato Region (Brandon and Collins, 2004). 

Future Work: 

The present status of creeping musk at the Miranda site should be assessed and 

recommendations made regarding the preservation of this species at the Miranda site. 

3.4.3 Oioi, Jointed Wire Rush – Apodasmia similis 

Though figured and mentioned by Morton (1983), as Leptocarpus simplex, oioi was not 

reported at Miranda by Merrett and Clarkson (1997). Strahan (1997) reported two isolated 

populations, one in freshwater near the road and the other “in a clump hemmed by a dense 

clump of Juncus kraussii”. 

Oioi is a widespread plant bordering estuaries and in salt marshes throughout New Zealand. 

It is also found around some inland lakes and freshwater marshes (Johnson 1989), and is not 

threatened on a national scale (Clarkson, pers. comm.) 

Strahan (1997) suggested that its apparent rarity at Miranda is associated with grazing and 

trampling by cattle. 

Future Work: 

Strahan (1997) discussed the potential for revegetation with this species at Miranda, noting 

“its height will not negatively impact open views of the coast from the road”. He also 

reported on methods of propagation and that “transplants would require protection from 

stock” and “weeding until canopy closure is achieved”. The divided sedge, Carex divisa 

(native to Europe and southern Africa), has invaded much of the potential habitat of oioi and 

would have to be suppressed to allow the oioi to establish. 

3.5 Threatened plants inside the stopbank 

3.5.1 Pale-flowered Kumarahou – Pomaderris hamiltonii 

Of the seven indigenous species of Pomaderris in New Zealand, the pale-flowered 

kumarahou, P. hamiltonii, is “Naturally uncommon – sparse” (de Lange, et al. 1999). 

This species closely resembles the widespread bright yellow-flowered kumarahou, P. 

kumarahou, differing in having masses of creamy-coloured flowers. 

The known distribution of pale-flowered kumarahou is Great Barrier Island, the Warkworth- 

Omaha area and the Kaiaua-Miranda area. 

Kaiaua-Miranda area. 

Plants are only known from seven sites, six of these being roadside cutting populations and 

only one on private land – Thompson’s Bush. In recent years there is evidence of a decline in 

the roadside populations. This has been caused by road widening and verge maintenance 

practices (herbicide applications and flail-mowing). 

Future work: 

It is suggested that the long-term conservation of this species requires: 

• Further work to indicate the extent of populations. 


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• Approaches to Franklin District Council regarding the preservation of roadside 

colonies from verge maintenance activities. [Note: Waitakere City Council has 

introduced measures to protect its endemic roadside Hebe bishopiana.] 

• Conservation measures and possible covenants on Thompson’s Bush. 

• Further propagation of this species. Work is currently underway at Unitec. 

3.6 Exotic invaders – Adventive plant species 

3.6.1 Spartina 

The estuarine grasses of the genus Spartina are vigorous invaders of coastal mangrove and 

salt marsh, estuarine areas and mudflats, rapidly colonising suitable bare ground. They are 

tolerant of immersion in saltwater. 

Three taxonomic entities are possible, Spartina anglica, S. alterniflora and S. x townsendii. 

Of these, only S. anglica has been identified from the Firth of Thames, though this area is 

within the known range of S. alterniflora, (Partridge 1987). The Auckland and Waikato 

Regional Councils have the responsibility for control of Spartina and other weeds in the 

Ramsar Site (in accordance with lines of jurisdiction). 

Spartina anglica can form dense stands. This grass has vigorously growing rhizomes and 

roots that form a dense mat near the surface of the mud or sand. Anchor roots penetrating a 

metre or more down into the mud secure the plants, which can grow to more than a metre 

high. This species spreads both by seed and by pieces of the rhizome breaking off the parent. 

Distribution. 

Spartina anglica, a native of Britain, was deliberately introduced to New Zealand in the 

1920s to stabilise mudflats and provide food for stock. It is now found in coastal regions 

throughout much of New Zealand (Partridge 1987). Within the Firth of Thames it is found in 

most of the mudflat areas and estuaries of the Coromandel Peninsula and along the Miranda- 

Kaiaua Coast. Nineteen sites were identified in the mangrove zone from the Waihou to the 

Waitakaruru River during a 2000 aerial survey (P. Thomson, personal communication 2000). 

Some of the Spartina patches covered areas of nearly one hectare. Much of the Spartina was 

sprayed and eliminated by late 2004, but there were still numerous small patches of it 

remaining in difficult to access areas (S. Clark, personal communication 2004). 

Significance. 

Spartina prefers deep, soft fertile mud with a sandy loam texture, (Environment Waikato 

1998). The dense mats of Spartina bind the mudflat and help to trap sediment. The vigorous 

growth habit, which can outgrow most of the native reeds and other plants on the mudflat 

edge, result in colonies extending over these flats. The plants trap silt, thereby altering the 

conditions for shellfish, particularly the cockle, Austrovenus stutchburyi. Some cockle beds 

have been wiped out by Spartina invasions (Department of Conservation 1998). 

Considerable areas may be colonized. Simpson (1995) reports on one such invasion in 

Victoria, Australia: “In the 1980s the mudflats off Nolans Bluff, situated on the landward side 

of the Inlet, were a prime habitat for migratory waders, significant both in numbers and 

diversity of species reported. Today, completely colonized by Spartina, the area has been 

deserted by waders, to the extent that Nolans Bluff is no longer included as a count 

location…” 


Future Work: 

Spartina is a recognised pest plant, restricted from national sale, propagation and distribution. 

It is declared a total control pest plant for the entire Waikato Region. The plan is for the 

Department of Conservation to assist Environment Waikato in the control and eventual 

eradication of it. Although the Waikato Regional Coastal Plan prohibits the discharge of any 

“toxic substance” into the coastal environment, Environment Waikato has amended the plan 

to permit the use of herbicides to control pest plants such as Spartina within estuarine areas. 


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Appendix 3.1 Plants Recorded at Miranda 

This list is largely based on the publication Vegetation Study of the Foreshore from Miranda 

to Kaiaua (Merrett & Clarkson 1997). A few corrections, additions and comments are added. 

Key: * = non–native + = native, but planted 

LICHENS 

Parmelia sp. (Strahan 1997) 

Ramalina sp. (Strahan 1997) 

Ramalina myrioclada (Maddison 2003) 

Teloschistes sp. (Strahan 1997) 

Usnea sp. (Strahan 1997) 

Xanthoria sp. (Strahan 1997) 

Xanthoria parietina (Maddison 2003) 

Sub-class: ANGIOSPERMAE 

Group: DICOTYLEDONES 

Family: APIACEAE 

*Apium nodiflorum – water celery 

? also recorded as Apium prostratum (Strahan 

1997). 

*Daucus carota – wild carrot 

*Foeniculum vulgare – fennel 

Lilaeopsis novae-zelandiae 

*Torilis arvensis – spreading hedge parsley 

Family: ASTERACEAE 

*Anthemis cotula – stinking mayweed 

*Aster subulatus – sea aster 

*Bellis perennis – daisy 

*Bidens sp. (Strahan 1997) 

*Carduus tenuiflorus – winged thistle 

Carduus pycnocephalus - slender-winged 

thistle (Maddison 2003) 

Cichorium intybus - chicory 

(Maddison 2003) 

*Cirsium vulgare – scotch thistle 

*Conyza albida – fleabane 

Cotula coronopifolia – bachelor’s button 

*Crepis capillaris – hawkbeard 

*Hypochoeris radicata –catsear 

*Leontodon taraxacoides - hawkbit 

*+Olearia lineata – shrub daisy 

*+Olearia traversii – Chatham Islands shrub 

daisy 

*Picris [=Helminotheca] echioides – oxtongue 

Pseudognaphalium luteoalbum – Jersey 

cudweed 

*Senecio bipinnatisectus – Australian fireweed 

*Senecio glomeratus - fireweed 

*Senecio jacobaea – ragwort 

*Senecio vulgaris – groundsel 

*Sonchus asper – prickly sowthistle 

*Sonchus oleraceus – sowthistle 

*Taraxacum officinale agg. - dandelion 

Family: AVICENNIACEAE 

Avicennia marina – mangrove, manawa 

Family: BORAGINACEAE 

*Echium plantagineum – Paterson’s curse 

*Echium vulgare – viper’s bugloss 

Family: BRASSICACEAE 

*Capsella bursa-pastoris – shepherd’s purse 

*Coronopus didymus - twin cress 

*Lepidium africanum – peppercress 

*Lepidium bonariense – Argentine cress 

*Lepidium pseudotasmanicum – narrowleaved 

cress 

*Raphanus raphanistrum – wild radish 

*Sisymbrium officinale – hedge mustard 

Family: CARYOPHYLLACEAE 

*Arenaria serpyllifolia – sandwort 

*Cerastium glomeratum – annual mouse-ear 

chickweed 

Spergularia media – sea spurrey 

*Stellaria media - chickweed 

Family: CASUARINACEAE 

*+Casuarina sp. – she-oak 

Family: CHENOPODIACEAE 

*Atriplex prostrata – orache 

*Atriplex sp. – orache 

*Beta vulgaris – beet 

*Chenopodium pumilio – clammy goosefoot 

Sarcocornia quinqueflora – glasswort 

Suaeda novae-zelandiae –sea blite 

Family: CONVOLVULACEAE 

*Calystegia sepium – pink bindweed 

*Calystegia soldanella – shore bindweed 

Calystegia silvatica - great bindweed 


Family: CRASSULACEAE 

*Sedum acre - stonecrop 

Family: EUPHORBIACEAE 

*Euphorbia lathyris – caper spurge 

*Euphorbia peplus - milkweed 

Family: FABACEAE 

*Lotus pedunculatus – lotus major 

*Lotus suaveolens – hairy lotus 

*Medicago arabica – spotted bur medick 

*Medicago lupulina – black medick 

*Medicago nigra – bur medick 

*Melilotus indicus – King Island melilot 

*Melilotus officinalis – yellow sweet clover 

Trifolium cernuum - drooping-flowered clover 

(Maddison, 2003) 

*Trifolium dubium – suckling clover 

*Trifolium fragiferum – strawberry clover 


*Trifolium glomeratum – clustered clover 

*Trifolium pratense – red clover 

*Trifolium repens – white clover 

*Trifolium resupinatum – reversed clover 

*Trifolium scabrum – rough clover 

*Ulex europaeus – gorse 

*Vicia sp. – “vetch” 

Family: GENTIANACEAE 

*Centaurium erythraea – centaury 

Family: GERANIACEAE 

*Erodium cicutarium - storksbill 

*Erodium sp. – storksbill 

*Geranium molle – dove’s foot cranesbill 

*Geranium purpureum – lesser herb robert 

*Geranium robertianum – herb robert 

Family: GOODENIACEAE 

Selliera radicans -remuremu 

Family: HALORAGACEAE 

Haloragis erecta 

Family: LAMIACEAE 

*Mentha pulegium –pennyroyal 

*Prunella vulgaris – self-heal 

Family: LINACEAE 

*Linum bienne – pale flax 

Family: LORANTHACEAE 

Ileostylus micranthus – pirita, papauma 

Family: LYTHRACEAE 

*Lythrum hyssopifolia – hyssop loosestrife 

Family: MALVACEAE 

*Malva neglecta – dwarf mallow 

*Modiola caroliniana – creeping mallow 

Plagianthus divaricatus – salt marsh 

ribbonwood 

Family: MORACEAE 

*+Ficus carica – fig 

Family: MYOPORACEAE 

*+Myoporum insulare – Tasmanian ngaio 

Family: MYRTACEAE 

Leptospermum scoparium - manuka 

Family: OROBANCHACEAE 

*Orobanche minor – broomrape 

Family: PHYTOLACCACEAE 

*Phytolacca octandra – inkweed 

Family: PLANTAGINACEAE 

*Plantago australis – swamp plantain 

*Plantago coronopus – buck’s horn plantain 

*Plantago lanceolata – ribwort, narrow-leaved 

plantain 

*Plantago major – broad-leaved plantain 

Family: POLYGONACEAE 

Muehlenbeckia complexa – pohuehue 

*Polygonum aviculare – wireweed 

*Rumex crispus – curled dock 

Rumex conglomeratus - clustered dock 


Rumex obtusifolius - broad-leaved dock 


*Rumex pulcher – fiddle dock 

*Rumex sp. (Strahan 1997) 

Family: PORTULACACEAE 

*Portulaca oleracea – pigweed, purslane 

Family: PRIMULACEAE 

*Anagallis arvensis ssp. arvensis – scarlet 

pimpernel 

Samolus repens – sea primrose 

Family: RANUNCULACEAE 

*Ranunculus repens – creeping buttercup 

Family: ROSACEAE 

*Aphanes inexspectata – parsley piert 

*+Eriobotrya japonica – loquat 

*Rosa rubiginosa – sweet briar 

Family: RUBIACEAE 

+Coprosma x cunninghamii 

Coprosma propinqua – mingimingi 

*Galium aparine – cleavers, goosegrass 

*Galium divaricatum – slender bedstraw 

Galium propinquum – mawe 

*Galium sp. – bedstraw 

*Sherardia arvensis – field madder 

Family: SCROPHULARIACEAE 

*Linaria arvensis – Field Linaria 

Linaria purpurea - purple linaria 


Mimulus repens –creeping musk 

*Parentucellia viscosa – tarweed 

*Verbascum virgatum – moth mullein 

*Veronica arvensis – field speedwell 

*Veronica persica – scrambling speedwell 

Family: TAMARICACEAE 

*+Tamarix sp. – tamarisk 

Family: VERBENACEAE 

*Verbena officinalis - vervain 

Family: VIOLACEAE 

+Melicytus obovatus 


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Group: MONOCOTYLEDONES 

Family: ALLIACEAE 

*Allium vineale var. compactum – wild onion 

Family: CYPERACEAE 

Avena barbata - Slender Oats (Maddison 2003 

[Baumea juncea – Reported and figured by 

Morton (undated), but not mentioned in 

Merrett and Clarkson (1997) and mentioned as 

not at Miranda by Strahan (1997).] 

Bolboschoenus caldwelli 

Bolboschoenus medianus 

*Carex divisa –divided sedge 

Carex divulsa – grey sedge 

*Cyperus eragrostis – umbrella sedge 

Cyperus ustulatus – giant umbrella sedge, 

Purua ‘grass’ 

Isolepis cernua – slender clubrush 

Isolepis nodosa – knobby clubrush 

Isolepis sepulcralis (Maddison 2003) 

Lepidosperma australe – square sedge 

Phalaris aquatica – Phalaris (Maddison 2003) 

Poa trivialis - Rough Meadow Grass 


Vulpia myuros - Vulpia Hair Grass 


Family: JUNCACEAE 

*Juncus bufonius – toad rush 

*Juncus gerardii – salt marsh rush 

Juncus maritimus var. australiensis – sea rush 

Juncus sp(p.) - rush 

Family: JUNCAGINACEAE 

Triglochin striata – arrow grass 

Family: PHORMIACEAE 

Phormium tenax – harakeke, NZ flax 

ALGAE 

Enteromorpha sp. 

Catenella nipae (Maddison 2003) 

Family: POACEAE 

*Agrostis stolonifera – creeping bent 

*Arrhenatherum elatius – tall oat grass 

*Avena fatua – wild oats 

*Briza maxima – quaking grass 

*Briza minor – shivery grass 

*Bromus diandrus – ripgut brome 

*Bromus sterilis – barren brome 

*Bromus hordeaceus – soft brome 

*Bromus willdenowii – prairie grass 

*Catapodium rigidum – feather grass 

*Cynodon dactylon – Indian doab 

*Dactylis glomerata – cocksfoot 

Dichelachne crinita 

*Holcus lanatus – Yorkshire fog 

*Critesion marinum – salt barley grass 

*Critesion murinum – barley grass 

*Lagurus ovatus – harestail 

*Lolium perenne – perennial ryegrass 

*Parapholis incurva – curved sea hard-grass 

*Parapholis strigosa – sea hard grass 

*Paspalum dilatatum – paspalum 

*Paspalum distichum – Mercer grass 

*Pennisetum clandestinum – Kikuyu 

*Poa annua – annual meadow grass 

*Poa pratensis – smooth meadow grass 

*Polypogon monspeliensis – beard grass 

Puccinellia stricta 

Rytidosperma sp. 

*Schedonurus phoenix – tall fescue 

*Sporobolus africanus – ratstail 

Austrostipa stipoides 

*Vulpia bromoides –vulpia hair grass 

Family: RESTIONACEAE 

Apodasmia similis – oioi 


4 Terrestrial Invertebrates & Mammalian Predators 

by Peter Maddison 

4.1 Mammalian Predators 

In 2003, a joint study on the mammalian predators at Miranda-Taramaire was commenced by 

the Department of Conservation, Miranda Shorebird Centre and EcoQuest Education 

Foundation. The study used Fenn traps and Black Trakka (Connovation) tracking tunnels 

in the Wildlife Reserve, Taramaire and surrounding areas. EcoQuest students looked at 

factors relevant to the siting of tracks/tracking tunnels, including vegetation type and height, 

and invertebrate fauna (in pitfall traps) in the immediate area of the traps. They found that 

there was considerable damage to the surface of the tracking cards caused by the Brown 

Garden Snail, Cornu aspersum. This introduced snail is common in the Miranda coastal area. 

Tracking and trapping results confirm the presence of the following mammalian predators and 

other mammals in the coastal area : 

Cat (Felis catus) 

Ferret (Mustela fero) 

Hedgehog (Erinaceus europaeus) 

House Mouse (Mus musculus) 

Rabbit (Oryctolagus cuniculus) 

Rats (Rattus sp(p.)) 

Stoat (Mustela erminea) 

Weasel (Mustela nivalis) 

There has been little direct observation of predators killing birds at Miranda. However these 

predators constitute a threat to ground-nesting birds, such as New Zealand Dotterel, Pied Stilt, 

Variable Oystercatcher and terns. Sick and injured birds are likely prey of these mammalian 

predators. 

Student Project References: 

Baker, H.A. (2003) Predator tracking at Miranda Reserve and Taramaire Conservation 

Reserve. EcoQuest Education Foundation, New Zealand. Unpublished. 

Behrmann, M.J. (2003) Mammalian predator tracking and trapping at the Robert Findlay 

Wildlife Area. EcoQuest Education Foundation, New Zealand. Unpublished. 

David, K. (2003) Tracking of mammalian predators. EcoQuest Education Foundation, New 

Zealand. Unpublished. 

Hall, J.L. (2002) The effects of cattle grazing on mangrove community structure at Miranda 

Ramsar Site, Spring 2002, Firth of Thames, New Zealand. EcoQuest Education Foundation, 

New Zealand. Unpublished. 


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4.2 Invertebrates 

Studies of the invertebrate fauna of the Miranda coastal area include the pitfall trap (ground) 

invertebrate studies by Flynn (2003) and Walls (2003). This method of trapping produced 

specimens of about 100 types of invertebrates. Most of these were only identified to family 

or group level. Walls (2003) also looked at the invertebrate fauna associated with native, 

compared with introduced, plant species at the Miranda Reserve. Other survey work at the 

Reserve includes collections by Chris Green of the Auckland Conservancy (DoC) and Peter 

Maddison of EcoQuest. 

4.3 Brown Garden Snail 

The introduced Brown Garden Snail, Cornu [= Cantareus] aspersum, is frequent under 

driftwood and debris in the coastal area. Gasowski (2003) and Sherwonit (2003) studied the 

biology and ecology of the snail in relation to climate, distance from the shore and vegetation 

type, etc. This snail caused significant damage by rasping the surface of the tracking tunnel 

cards. 

4.4 Mangroves 

Motta (2002) studied the invertebrate fauna on mangrove trees at 5 different sites along the 

Miranda Stream and found differences in the distribution and abundance of mites (Acari), 

spiders (Araneae) and bark lice (Psocoptera) 

Appendix 4.1 Preliminary List of Invertebrates (identified to species) 

Phylum : ARTHROPODA 

Class : ARACHNIDA 

Order : ACARI 

Family : ERIOPHYIDAE 

Acalitus avicenniae (Lamb) 

Erineum on mangrove, Avicennia 

Order : ARANEAE 

Family : ARANEIDAE 

*Eriophora pustulosa (Walckenaer) – Garden Orbweb Spider 

Family : PISAURIDAE 

Dolomedes minor (Koch) – Nurseryweb Spider 

Family : THERIDIDIIDAE 

Achaearanea veruculata Urquhart – New Zealand Cobweb Spider 

Steatoda capensis Hann – False Katipo 

Class : INSECTA 

Order : COCCINELLIDAE 

Coccinella undecimpuncata L. – Elevenspotted Ladybird 

Family : CURCULIONIDAE 

Gymnetron pascuorum (Gyllenhal) 

Family : SCARABAEIDAE 


Heteronychus arator (Fabricius) – Black Beetle 

Family : SILVANIDAE 

Cryptamorpha desjardinsi (Guerin) – Desjardin’s Flat Beetle 

Order : HYMENOPTERA 

Family : APIDAE 

*Apis mellifera L. – Honeybee 

Order : LEPIDOPTERA 

Family : ARCTIIDAE 

Utetheisa pulchelloides Hampson Heliotrope Moth 

Family : TINEIDAE 

Opogona omoscopa (Meyrick) 

Phylum : MOLLUSCA 

Class : GASTROPODA 

Family : HELICIDAE 

Cornu aspersum (L.) [= Cantareus aspersus] Brown Garden Snail 

Family : HYDROBIIDAE 

Potamopyrgus antipodarum (Gray) 

Family : HYGROMIIDAE 

Prietocella barbara (L.) Banded Conical Snail 


Flynn, B.B. (2003) Invertebrates at the Robert Findlay Wildlife Reserve at Miranda : Their 

abundance and distribution. EcoQuest Education Foundation, New Zealand. Unpublished. 

Gasowski, C.W. (2003) The brown garden snail at Miranda. A study of Cantareus aspersus 

population densities, distributions and behaviours. EcoQuest Education Foundation, New 

Zealand. Unpublished. 

Sherwonit, L.E. (2003) The coastal habitat preferences of Cantareus aspersus based on 

microclimate. EcoQuest Education Foundation, New Zealand. Unpublished. 

Walls, R.J. (2003) Native and exotic invertebrate types found associated with native and 

exotic vegetation in the Robert Findlay Wildlife Reserve. EcoQuest Education Foundation, 



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5 Mangroves: The Cornerstone of a Dynamic 

Coastal Environment 

by Bill Brownell 

(with contributions from Marie Buchler, Ria Brejaart, Bruce Burns and Steve Clark) 

5.1 History 

Writing in 1769, Captain Cook comments on his discovery of the “River Thames” (meaning 

the current Firth of Thames and the Waihou River combined), “About the entrance to the 

narrow [Waihou] part of the River the land is mostly cover’d with Mangroves and other 

Shrubs, but further in are immence (sic) woods of as stout lofty timber as is to be found 

perhaps in any other part of the world: in many places the woods grow close upon the very 

banks of the River but where it doth not the land is Marchey (sic) …” (Beaglehole 1968). 

Mangroves were seldom mentioned in subsequent accounts, such as the Hauraki Minute 

Books of the Maori Land Court records (Phillips 2000) and the history of the Hauraki Plains 

(Tye 1974), mainly because they were not a dominant vegetation type in the area at the time, 

and were considered by both Maori and Europeans to be of little value. 

The aerial photography series of the southern Firth of Thames coast and Hauraki Plains from 

1944 indicate mangroves growing only at the mouths of the Waihou and Piako rivers. In 

1952, mangroves extended out slightly more into the tide from the river mouths (including the 

Waitakaruru), and they already had achieved quite dense coverage along the banks of the 

lower 2-3 kilometres of the Piako. A smattering of them were evident in small groupings on 

the coast extending away from the river mouths, with most of the intervening coastline still 

showing as apparently shelly/sandy beaches with no mangroves. By 1963 the whole coast 

from the Miranda Stream right around to the Waihou had limited coverage of fringing 

mangroves, with increasingly extended groupings around the river mouths. Subsequent aerial 

photographic records (1977, 1983, 1992, 1993, 1996 and 2002) provide a chronology of 

mangrove advancement in the upper Firth of Thames over the past 40 years. According to 

veteran local fishermen, the greatest rate of advancement has occurred over the past 3 years 

(2002-2004), mainly since the last aerial photos were taken in February 2002 (R. Smith and 

Peter Thorburn, personal communications 2004). 

5.2 Ecology 

The mangroves, or manawa, of the Firth of Thames, and indeed throughout their range in 

northern New Zealand, are of a single species originally called Avicennia marina var. 

resinifera, more recently referred to as A. marina var. australasica (Duke 1991, Young and 

Harvey 1996 and Burns 1998), and now simply identified as A. marina in both New Zealand 

and southern Australia (A-M Schwarz, personal communication 2004) 

Mangroves have been in New Zealand for at least 9,800 years, and most likely arrived here 

considerably before that in the form of propagules drifting over from Australia in the middle 

tertiary period (Crisp, et al. 1990). A. marina is the most cold tolerant of all the numerous 

mangrove species found mainly between the tropics of Cancer and Capricorn around the 

world, and currently exists at a latitude of 38 o 54’ on the south coast of Australia. The 

southern margin of the Firth of Thames and associated tidal rivers sustains (at 37 o 14’) one of 

the most southerly occurrences of mangroves in New Zealand, and by far the most abundant 

population found near the current limits of its range. There are also substantial mangrove 

populations at nearby Tauranga and Ohiwa Harbours southeast of the Firth of Thames. 


The extensive mangrove community that defines the coastline of most of the Ramsar Site 

from the Miranda Stream in the west around to the mouth of the Kauaeranga River next to 

Thames in the east (map, Figure 1-1) covered approximately 900 ha. in 1997 (Burns 1998). 

From the early 2002 photos, Hauraki District Council calculated the total coverage to be 1084 

ha., exclusive of the small stretch of typically mangrove-lined coast between the Waihou and 

Kauaeranga river mouths. 

This is the only mangrove population of any size and permanence found on an open coast in 

New Zealand. This is due to a combination of favourable conditions there: very shallow 

water, normally low wave energy, extensive deposition of sediments, high nutrient levels and 

regular re-oxygenation of the water through a high ratio of atmospheric contact to water 

volume in the shallows at high tide (Nature Conservation Council 1984). It also offers a 

desirable salinity, which normally in this area oscillates within the 15 to 24 parts per thousand 

preferred range of A. marina, and a high level of total available sunlight throughout the year. 

The slope of the mangrove-dominated mudflats (the active progradation zone of young trees) 

just west of the Piako River mouth was calculated by Young and Harvey (1996) to be a 

minimal 1 in 470. From this 200-300 m wide mudflat band (now further out to sea than it 

was in 1996) that gets washed to varying degrees on all high tides, the mature mangrove 

forests extending back for 500-600 metres of perfectly flat ground toward the stop bank only 

get a light bathing of sea water on spring tides. 

All along the 9 km of coast between the mouths of the Piako and the Waitakaruru, the sloping 

mudflat zone of vigorous mangrove advancement is backed up by very stable mature forest 

(on the now flat ground that was built up in the progradation process of the past 40-50 years). 

In 2004 this forest is showing some signs of weakness (yellowing leaves, stunted growth, 

partial and total die-off), particularly in some of the more landward positions where 

characteristic saltmarsh vegetation is becoming more dominant and mangroves are dying out. 

Avicennia marina prefers a substrate that is rich in organic silt/clay/ muds (with not too high a 

percentage of sand) of combined marine and terrestrial origin that overlay compacted anoxic 

sediments dominated by black hydrogen sulphide. For establishment, and stability in the face 

of storms, they seem to do best on pockets or banks of shell dominated by the three abundant 

species of bivalve in the upper Firth of Thames (Mactra ovata, Austrovenus stutchburyi and 

Macomona liliana). 

These are the same intertidal deposits of dead shells that are the precursors of the Chenier 

ridges that develop at the edge of the tide from the Miranda Stream northward to Whakatiwai, 

where most of the sporadic and narrow coastal mangrove cover is a remnant of populations 

that earlier evolved in the coastal lagoons behind the frontal Chenier ridges (Woodroffe et al., 

1983). As the Chenier is driven inland, mainly by northeasterly storms and very high tides, it 

migrates through the mangroves, partially burying them, and eventually killing them. The 

many elongated coastal lagoons (part of the Chenier plain development process) and the 

banks of streams and drains of the Miranda-Kaiaua coast currently support small populations 

of healthy mangroves at their margins. 

The entire west coast from the Miranda Stream south to the Waitakaruru River is now 

occupied by bands of mangroves up to 700 m wide (south of the Karito Canal), of moderate 

to heavy densities, anchored in rich sediments originally trapped by the accumulations of 

shell in the upper intertidal. 

Mangrove habitat along the Waihou and Piako Rivers has been totally modified over the 

years by timber harvesting, heavy boat and barge traffic, dredging, channelling, stopbank 


35

36 

construction and intensive farming, but A. marina is still found at considerable distances 

upstream. In the Piako, there is measurable saltwater penetration 50 km upriver, and 

mangroves extend 5-6 km inland (Young & Harvey, 1996). 

The average height of A. marina at its southern limits is less than one metre, though there are 

extensive groupings of mangroves throughout the Ramsar site made up of trees in the 2-3 m 

range (particularly at the margins of the tidal creeks), and those lining the Piako River mouth 

are mostly in the 3-6 m range. Many of the Ramsar Site trees of 1 m or less have trunks with 

a diameter at the base of 80 mm or more, and a canopy of up to 5.5 m. Many stands of A. 

marina in the Far North (Kerikeri to Parengarenga) contain trees that are predominantly in the 

6-9 m range. The average height of established populations at the margins of tidal creeks in 

Whangarei Harbour is five metres, while those inhabiting poorly drained (=low in oxygen) or 

less tidally washed areas may have a mean height of less than 1 m. 

B. Burns (personal communication 2001) reports that, “The difference in tree size and shape 

both within and between populations is also related to differences in productivity". Tall 

mangroves are more productive than stunted trees (Woodroffe 1982). Differences in tree 

form are often spatially distributed in a population with tall mangroves of several metres 

height occurring at the front edge of a mangrove forest or around tidal drainage channels, and 

stunted mangroves often less than 1 metre tall occurring at the back of the forest and in 

interfluves between drainage channels. There is often a gradation of tree form between these 

extremes of size. De Lange and de Lange (1994) suggest that differences in tree form are 

related to sediment textural differences, with taller trees growing on finer sediments (which 

are richer in available phosphates than coarse sediments). Passioura et al (1992) hypothesise 

that the difference in growth form is a result of differences in the build-up of salts as a byproduct 

of transpiration, and that greater flushing of soil water near the drainage channels 

limits the salinity of these areas, allowing taller mangroves to grow. In contrast, stunted 

mangroves are formed in areas where flushing is inadequate to prevent salinity build-up.” 

Very few other vascular plants occur amongst the mangroves, but in the better drained sites 

(slightly higher ground) salt marsh ribbonwood (Plagianthus divaricatus), mingimingi 

(Coprosma propinqua) and pohuehue (Muehlenbeckia complexa) may establish, mainly near 

the essentially dry margins of the stopbanks, amongst the old (and stunted) mangroves. 

There are some areas of “salt marsh savannah” within the extensive new mangrove forests 

between the Waitakaruru and Waihou rivers where these 3 shrubs are well established 

(especially mingimingi), usually in association with glasswort (Sarcocornia quinqueflora). 

One such Sarcocornia-dominated savannah occurs as vast patches in the vicinity of the 

Appletree Pump (midway between the Piako and the Waitakaruru), extending as much as 200 

m from the stopbank to the edge of the dense mangrove forest between it and the sea (photo 1, 

Figure 5.6). As little as a 5-10 cm difference in elevation in these areas can be the 

determining factor as to whether the ground is occupied by stunted mangrove trees or 

glasswort (and eventually by one or more of the saltmarsh shrubs). 

Aerial photographs also show that these marginally higher, cleared (naturally, or by grazing) 

areas amongst the mangrove may be invaded by the introduced and noxious Spartina grass 

(Thomson 2000). 

There is no competition from any other native plant that prefers muddy intertidal brackish 

water habitats within the mangrove’s range in New Zealand, and there are no devastating 

pests or diseases that place regular stresses upon them. Thus, A. marina is capable of 


establishing in areas where temperatures may occasionally drop below their normal tolerance 

limits, or in semi-exposed locations where they could be uprooted. 

During our seven years of observation (1998-2004) in the Waitakaruru and the Karito, 

individuals and groups of seedlings have been killed by frosts of –2 ºC to –3 ºC, many plants 

at the outer edges of mangrove forests (including some that were several years old) have been 

uprooted by storms, and some significant die-offs have occurred (often involving very mature 

plants). 

In spite of these sporadic and localized knock-backs, the Firth of Thames population has been 

in steady expansion over at least the past 40 years. Burns and Ogden (1985) report that the 

extensive Ohiwa Harbour population (at about the same latitude) has been increasing 

exponentially since about 1905, and similar rates of increase are happening in Tauranga 

Harbour. De Lange and de Lange (1994) show that the mangroves at this latitude are not 

necessarily at their southern climatic limit. The vigorous Firth of Thames population forms 

vast expanses of dense forest that in some areas of the coast extends out 600 metres or more 

into the intertidal zone. Seed production was observed to be extensive along the Miranda 

Coast in 2000 and 2001. After the summer propagule drop from the trees (January – 

February) there was widespread establishment of seedlings, especially in 2001, and blankets 

of seeds and propagules being carried by the tides up and down the coast. 

Well-established mangroves have extensive root systems that anchor the plant in soft 

sediments, with pneumatophores extending upwards for essential aerial respiration (as the 

mud is usually low in oxygen, or totally anoxic). The root systems of an individual mature 

mangrove may cover up to 10 m 2 and form a network, together with the pneumatophores, that 

is effective in stabilising the mud and trapping more sediments. This may, in fact, work to the 

detriment of the plants, especially in the denser forests like the ones around the lower Piako. 

Young and Harvey (1996) found that sediment accretion rates increase with greater 

pneumatophore density, and suggest that the most successful plants find a balance between 

the need for more respiration capacity and the need to offer less surface area for the 

accumulation of sediments around them. 

Fruits of the mangrove start to germinate while still on the plant, so that the seed when it falls 

has two large, green cotyledons that are ready to grow. The seeds float in the sea and may be 

carried for many kilometres to new locations, though there appears to be no natural transfer of 

propagules around Cape Reinga, and thus there is significant genetic difference between east 

and west coast populations (Crisp et al. 1990). Propagules that have the good fortune of 

being carried by the tide onto a well-drained, nearly flat, sulphide-rich muddy substrate that 

offers a high nutrient content, low current and wave action, will germinate rapidly and soon 

establish a fresh colony. If they have not found a suitable place to take root within 4-5 days, 

they will probably lose their viability (de Lange & de Lange, 1994). Due to the virtual 

isolation of the southern Firth of Thames population, an abundance of appropriate substrate 

for germination, and quite variable tidal flushing rates, it is likely that a high percentage of the 

young plants establishing there are of a neighbouring provenance. 

Mangroves in New Zealand produce an average of eight tonnes of dry leaf litter/hectare/year, 

which is four times the biomass production of good quality pasture, and 20x that of the open 

ocean (Woodroffe, 1982). Leaf fall happens mainly between December and April, and 

decomposition proceeds rapidly in the warm autumn water. This mangrove leaf litter, and 

lesser amounts of other organic matter from the land (mainly grasses and upland forest litter) 

and sea (mainly algae), is the third significant nutrient source (after upwelling and agricultural 

runoff) that yields exceptionally high plankton productivity in the Firth of Thames. This litter 


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38 

also provides a direct source of energy for detritus feeders like polychaete worms, crabs and 

snails (many of which use the mangrove roots for shelter), and a significant substrate for 

nitrogen fixation. 

Currently there are persistent mangrove incursions into shallow coastal lagoons of the 

Chenier plain at Miranda, particularly the ones that are used mainly by stilts for roosting and 

feeding. Eventually these areas will be taken over by the mangroves. 

A. marina is a very resilient plant, coping with tidal inundation twice daily and with 

alternating sea-water and brackish water around its roots, with its lower stems and leaves 

regularly being covered by muddy water, and its tender leaves often succumbing to frost. 

Caterpillars of the mangrove leafroller moth, Planotortrix avicenniae, attack the young leaves 

and leaf buds. Infestations of this moth can occasionally cause severe damage to young 

growth, and eventually defoliation and dieback of the trees, but such extreme reactions appear 

to happen when the plants are suffering some particular stress, e.g. frost damage, soil nutrient 

depletion, presence of pollutants, smothering by sediments, etc. 

An eriophyid mite, Aceria avicenniae, causes pustule-type swellings on the undersides of the 

leaves, but these do not seem to result in leaf mortality, even when coverage is extensive. 

The lower stems of the mangrove are often covered with lichens, e.g. Ramalina, and algae 

e.g. Catenella, Rhizoclonium and Neptune’s necklace, Hormosira. The stems and 

pneumatophores also provide firm-settling surfaces for the same species of algae, barnacles 

(Elminius modestus) and molluscs such as mussels and oysters. The burrowing mud crab, 

Helice crassa, and the mudsnail, Amphibola crenata, are particularly common in mud 

amongst the mangroves. The burrowing Nereid worm, Nicon aestuariensis, forms U-shaped 

burrows which penetrate down into the black, anoxic mud lying not far below (5-10- cm.) the 

surface layer (see Chapter 7, Benthic Fauna). The stable mangrove environment also 

provides habitat for spawning, nurseries and prey species for invertebrates, fish and birds. 

5.3 Accretion of Sediments and Advancement of Mangroves 

The Firth of Thames Ramsar Site is an outstanding example of the interrelationship of three 

key estuarine forces: 

• A semi-protected embayment (though fully exposed to northerlies) with an extensive 

area of shallow water around its broad margins due to the interplay of 

geomorphology, weak littoral currents (mainly tidal) and the build-up of sediments, 

• Continued accretion of mainly land-derived sediments, primarily at the southern and 

western margins of the upper Firth (from Kauaeranga to Kaiaua), 

• Steady advancement of mangroves further into the tide along these margins, as both a 

cause and an effect of the sedimentation. 

Young and Harvey (1996), in their study of the mangroves at the mouth of the Piako River 

(western edge), found through comparisons of five principal series of aerial photographs from 

1944 to 1993 (and by running two transects for ground truthing) that the mangroves advanced 

by about 200 metres over those 50 years. This was attributed to an estimated total vertical 

sediment accretion of 32 cm in that period, creating favourable depths and desirable substrate 

for mangrove establishment extending considerably beyond their previous margins. Sea 

levels in the Firth have remained constant for the past 1200 years. Young and Harvey (1996) 

also found that the maximum accretion rate, as measured by transect stakes in the Piako 

mangroves in 1993, was 16 mm in five months. This would translate into a maximum 

potential rate of 38 mm in a year, or 38 cm in ten years. 


It appears from our observations and the experience of some local residents and Steve Clark 

(personal communication 2001) that the accretion rate has been much faster in the past 20 

years, with an even greater rate since the 2002 photos. Table 5.1 compares the widths of the 

mangrove band in 1977 and 2002 at selected points from Miranda Stream to the Waihou. 

Woodroffe et al. (1983) note that the mangroves of the southern shore of the Firth “have 

prograded into the open waters from isolated stands in 1961 to a nearly continuous fringe up 

to 300 m wide since 1977”. 

One approximate measure of the change is the differential of land level between the landward 

and seaward sides of the stopbanks. The land outside the stopbank has increased to a level 1- 

2 metres higher than on the inland side, even along the western shore, where the stopbank was 

constructed more recently, in 1946 (S. Clark, personal communication 2001). Another 

indication is the accretion that has occurred around the post and tyre retaining wall that was 

built in 1988 to protect the southeastern edge of the Karito Canal mouth slightly east of the 

westerly bend in the stopbank, to follow the southern margin of the Canal. Over thirteen 

years, the level of the land surrounding the posts had steadily increased by 60 centimetres (S. 

Clark, personal communication 2001). 

In terms of mangrove advancement, there were only sparsely scattered young mangrove trees 

and saplings to the seaward side of the Karito retaining wall when it was built. Now, in 2004, 

the mangrove forest extends out more than 600 m beyond the remains of this wall (Figure 

-5-2), most of which has apparently occurred since 1988. The trees inhabiting the coastal 

band of about 100 m closest to the stopbank are dying out due to diminishing exposure to the 

tides. 

At the eastern side of the Waitakaruru River mouth, the advancement of mangroves has been 

between 250 and 300 m in 21 years since three posts were placed at the mouth in 1980 (R. 

Smith, personal communication 2001). The posts are still standing, but now far back in dense 

mangrove forest lining the river entrance. In the three years from 2002 to 2004, a new band 

of dense young mangrove trees has advanced 50-100 m beyond the 2001 line. 

Aerial photographs from 1963, 1996 and 2002 (Figures 5.1, 5.2, 5.3) indicate a mangrove 

advancement at the western side of the river mouth of over 600 m in the intervening 38 years. 


39

Table 5-1 Comparative Widths in metres of Firth of Thames Ramsar Site Mangrove Forest – 1977 and 2002 - at selected points around the coast, starting from the 

outer edges of the stopbanks and extending out to the edge of the highest density zone. 

Land base point on stop 

bank for start of transect 

Location description 

And distance(s) to neighbouring point(s) 

1. Miranda Stream S (near bridge) 1st easterly bulge in stopbank just S of stream mouth, 2752 m N of Hot Springs Drain and 

5673 m N of Karito Canal 


Bearing 

(degrees) 

Width 

1977 

(metres) 

2002 

88 85 218 

2. Miranda Stream S 2 nd bulge (S end of stopbank embayment) – 414 m S of point 1 73 215 438 

3. Hot Springs Drain South bank 

4. Karito Canal N bank 

Easternmost point of stopbank just S of Drain (note: recent build-up of mud/shell bank out 

beyond leading edge of mangroves … potential area for more extensive advancement) 

From easternmost point of small bulge in stopbank, 98 m N of canal margin (Note: variable 

medium to high densities in this band) 

30 325 422 

24 433 490 

5. Karito Canal S bank From start of 1988 post & tyre erosion control wall near stopbank elbow 60 0 785 

6. Waitakaruru River W (north) 

7. Waitakaruru River E 

Direct line out from race on Gavin Singh’s farm (parallel to river) (Note: variable medium 

to high densities in this band) 

Just E of stopbank triangle on Laing’s farm, 1635 m E of Waitakaruru R. margin 

(continuing northerly line of old boundary hedge and bridge over foreshore canal) 

30 615 847 

344 373 636 

8. Appletree Pump Terminus of farm track that starts 292 m W of Pipiroa Rd. , 3067 m further E from point 7 338 560 904 

9. Piako River W 

10. Piako River E 

11. Waihou River W 

From big bend in stopbank just beyond Buchanan Rd. terminus, parallel to Piako River, 

4422 m from Appletree Pump 

Direct line N from McGaffin farm race off Shelly Beach Rd., 362 m E of Piako River 

margin 

Direct line N from Orongo Rd. terminus (following stopbank), 565 m W of Waihou R. 

margin, 2424 m E of point 10 

350 520 632 

322 627 740 

324 - 742

41 

Figure -5-1 June, 1963 aerial photo of Waitakaruru River to Karito Canal area, showing 

minimal coastal mangrove coverage. 


42 

Figure -5-2 Waitakaruru-Karito area in 1996, showing mangrove advancement. 


43 

Figure -5-3: Waitakaruru River to Karito Canal - February 2002. 


44 

5.4 Karito Canal Field Studies 

We carried out ten field investigations of the mangrove community of the Karito Canal 

between the open sea and the bridge over the Coast Road from November 8, 1998 to July 26, 

2001. Among these were five field investigations carried out by EcoQuest university students 

and staff for the collection of data from random plots and quadrats in three zones: the dieback 

area, the dredge spoils area and in the dense forest beside the spoils area (EcoQuest Education 

Foundation Student Research Reports, October 1999, March 2000, October 2000, March 

2001, June 2001.) 

From our initial two exploratory visits by kayak at high tide in November 1998, two principal 

observations were recorded: 

• The entrance to the Canal from the Firth of Thames was a long, slightly curving channel 

lined on each side by extremely dense and healthy looking mangrove forests composed 

mainly of trees 2-3 metres high, extending approximately 400 metres inward (westerly) 

to the first significant bend. At the mouth of the channel, particularly on the northern 

side, the mangrove zone was poorly defined, just like the outer fringes of the mangroves 

all along this coast, with saplings and young trees in scattered clumps or as solitary 

individuals occupying a band 30-70 metres wide, more or less spanning the mid-tide 

zone. The forest was denser on the south side for about 40 metres before the coverage 

on the north thickened up. At this point the width of the channel was 7-10 metres. 

Upstream from there, heading into the left-hand bend that forms an oxbow angling back 

to the right in front of the stopbank, the channel was 4-5 metres wide (Figs. 5.4, 5.5, 5.6). 

Except for the outer area of newly established scattered mangroves, the channel was 

formed by steep-sided stable banks for a distance of over 450 metres up to the right-hand 

bend at the stopbank, demonstrating only minimal erosion (mainly by numerous rivulets 

moving the waters of an ebbing spring tide off the flats). 

• One of the several significant patches (0.3 hectare or more) of mature mangrove dieback 

that we had observed along this coast from Waitakaruru to the Hot Springs Drain was 

just behind the dense fringe of mangroves at the south side of the mouth, extending E-W 

for about 100 m. In the main part of the dieback area, as seen from the outer perimeter 

of scattered young mangroves south of the Canal mouth, there appeared to be nothing 

but dead mangrove trunks and branches covered in lichen. 

5.5 Dredging in the Mangroves 

On January 28, 1999, we did a survey of the Canal on foot (starting at the East Coast Road 

bridge) to appraise the effects of dredging that had been carried out in early December 1998, 

about six weeks before. The dredging commenced at the flood control gate about 300 metres 

downstream from the bridge. The tracked dredge had worked its way along the south bank, 

out to a point about 100 metres from the Canal mouth (finishing just beside the inner part of 

the dieback area described above). Here it was forced to discontinue due to very soft mud on 

the bank. 


45 

1 Upstream view about 100m from the mouth. Future dredge spoils strip all along south 

bank (left) – 8 November 1998. 

2 Students studying dieback area – 7 March 2000. 

3 Dieback area regeneration – 26 July 2001 (looking south, away from dredge spoils). 

Figure -5-4 Three time series photos of the dredge spoils strip along the Karito Canal 


46 

The movement of the machine along the right (south) bank, and the deposition of dredge 

spoils in its path, created a swath 5-8 metres wide in which there was no living vegetation 

(Figure 5.5). The spoils were made up of mud (mixture of blue clay, black silt and sand, still 

with a strong smell of hydrogen sulphide). There had been two very heavy rains since the 

dredging was done, and the rough edges of the dredge mounds had been smoothed down, 

exposing great quantities of shellfish that had been excavated, the majority of them alive at 

the time. About 95% of the shells were Mactra ovata, and there were about six large piles of 

Pacific oyster (Crassostrea gigas). The remaining (approx. 1% of the shells) were 

Austrovenus stutchburyi and Macomona liliana. 

Along the edge of the bank there were scattered remains of mangrove trees that had been only 

partly flattened, and still had some green leaves on them (Figure 5.5). The trees of the 

remaining forest along the edge of the dredging were shorter by ½ to 1 m and of a less intense 

green than those which had previously lined the channel, but were of a similar density. All 

mature mangroves, from the youngest to the oldest, all along the Canal, were covered in 

flower buds (unseasonable, and unusually heavy). Some of the new season’s propagules were 

just developing into seedlings in areas not affected by the dredging. 

This dredging was part of a permitted activity under Waikato Regional Council policy, with 

management of operations by Hauraki District Council in response to a need expressed by the 

West Piako Drainage Committee. It had happened that flows had been sluggish in the upper 

reaches of farmlands drained by the Karito, and it was determined that this had been caused 

mainly by the build-up of sediments in the lower reaches of the Canal, beginning at the edge 

of the stopbank. The oysters, in particular, had accumulated in several locations (starting at 

the floodgate), and were a major force in the build-up of sediments. 

It was already evident at this stage that some of the oyster beds still remained in the Canal six 

weeks after the dredging, and that spoils were starting to wash back into it. The termination 

of the dredging, 100 metres short of the Canal mouth, created a barrier which appeared to be 

an impediment to the free flow of water outward, and a possible cause of further sediment 

build-up upriver of it. 

The area of the strip that was affected by the dredging was greater than expected, as the 

machine slipped into the canal on several occasions, and had to move further into the 

mangroves for stability. It is now difficult to know how the destruction of all of the biggest 

and healthiest trees along the right bank will affect the remaining forest (and the now 

completely exposed dieback area) in the long run. So far we have observed no apparent 

adverse effects in terms of the remaining mangroves. In December, 2004, regeneration of this 

area was extensive (photo 2, Figure 5.6), though remaining mounds of dredge spoils 25 to 40 

cm high close to the established trees next to the spoils area showed virtually no regeneration. 

In the course of seven subsequent surveys of the area, finishing on July 26, 2001, the extent of 

the four main oyster beds in the Canal increased significantly and the right bank eroded away 

into the Canal (becoming a gentle slope rather than a nearly vertical bank), though this has 

stabilised by 2004 with the re-establishment of the mangroves at the edge of the Canal. The 

mounds of dredging spoils gradually eroded (but to a lesser degree at the inner edge) and the 

Canal in 2004 is heavily silted with deep soft sediments. Drainage is, indeed, becoming a big 

problem again, due not only to the filling in of the lower Canal, but also to more sediments 

being brought inland on spring tides, more sediments washing off the farms, and a scarcity of 

big storms to help flush out the system, leading to the need for more maintenance dredging at 

all levels (S. Clark, personal communication 2004). 


47 

Looking west: 

1 Dredge spoils after 6 weeks, showing almost the same view as 8 November 1998 

photo prior to dredging. 28 January, 1999. 

Looking east to Coromandel: 

2 Eroded dredge spoils, 7 March, 2000. 

3 Revegetation underway 26 July, 2001. 

Figure -5-5 Photo of Karito Canal before dredging, and 2 time series photos of the Karito 

mangrove dieback area 


48 

1 Karito Canal: nearly six years after photo 1, Figure 5.5, showing near total recovery, with many of 

the oldest mangroves in flower and/or seed. 

2 Revisiting photo 2, Figure 5.5, nearly five years later. 

3 200 m N of stopbank (Appletree Pump Station) between Piako and Waitakaruru, looking NW over 

the Firth of Thames (obscured) to the Hunua Range. 

Figure 5-6 December 2004 updated mangroves photos 


49 

5.6 Revegetation of the Spoils Area 

In order to chart the progress of revegetation in the dredging spoils area along the Canal, five 

data sets were taken between October 1999 and June 2001 from five plots (each of 5m 2 ), 100 

m apart. From visual observations in January 1999 (six weeks after the dredging) no 

propagules had established in the area (Figure 5.5). Later on October 8, there were signs of 

natural revegetation, with the plots yielding an average of 0.4 seedling (of20 cm,

50 

Waitakaruru area, as well as at several locations north of there (as far as the mouth of the 

Miranda Hot Springs Drain). 

It was very difficult to define the precise areas of dieback, as it occurred in patches of varying 

size and intensity, and often one or more branches would be sporting a full set of green leaves 

while the rest of the tree was decidedly dead. In fact, our October 2000 data from 4 x 4m 2 

plots in the control zone (healthy mature mangrove forest) at the Karito Canal, collected three 

years after the major dieback event, revealed a total of 316 trees, of which 56 were dead, an 

average of 16.2 and 3.5 per m 2 , respectively. 

Over 2 ½ years, we did not observe any indications of poor health in this control zone, other 

than the fact that the trees are shorter, with leaves not quite as green as those on the original 

trees lining the Canal beside them, and that they showed slight signs of mite and leafroller 

caterpillar parasitisation. As 29 of the dead trees (52%) were under 100 cm in height, and 

none were over 172 cm, they could have died as a result of overcrowding. 

Burns (1998) noted that in the Waitakaruru dieback area, the leaves below the high tide mark 

on trees were unaffected by defoliation, and that many of the attached leaves (higher up) had 

been “rolled” to encase insect larvae, which he identified as that of the leafroller moth, 

Planotortrix avicenniae. This species is only found on New Zealand mangroves. Bert Laing 

(personal communication, 2001) recalls that the 1997 dieback, which affected a large area 

adjacent to the stopbank in front of his farm, coincided with repeated heavy (probably –1ºC to 

–2ºC) winter frosts, and with the heaviest mangrove leaf infestations of leafroller caterpillars 

in the spring that he had ever seen. 

Burns (personal communication 2001) relates that there were some episodes of heavy 

mangrove defoliation caused by the same species of moth around Matakana Island (Tauranga) 

in the 1960s, and that there are several published reports from other parts of the world 

implicating Lepidopteran larvae in the defoliation of mangroves. Burns (personal 

communication 2001) postulates that the apparent 1997 population explosion of P. 

avicenniae could have been due to changes in the foliar chemistry of mangroves leading to 

increased leaf palatability, or a decline in predation or parasitism on P. avicenniae, leading to 

increased survival. 

There has been speculation that some source of pollution may have caused soil toxicity or 

otherwise stressed the mangroves, making them less resistant to caterpillar attack. Studies 

were proposed for addressing this possibility, but they were not initiated due to signs of 

mangrove recovery that were reported in February 1998 (Burns, personal communication 

2001). In fact, the now documented widespread and patchy nature of the dieback, often 

occurring inside healthy stands of trees at the water’s edge, suggest that water-borne toxicity 

is not a likely cause. The only possible point sources of pollution anywhere near the areas 

affected are the small piggery and the village sewage treatment plant at Waitakaruru. Local 

residents have reported that there were no noxious odors or evidence in the water of any 

pollution event during the winter of 1997, nor any malfunctions of the sewage plant. 

Several local observers have noted that an unusual widespread yellowing-off of mangrove 

leaves occurred over a wide area starting at the east bank of the Waitakaruru River in March 

of 1997, leading to the progressive defoliation and dieback in the winter of 1997 (Rex Smith, 

personal communication, 2001). The only environmental event of note that happened 

immediately prior to this was strong back-to back cyclones that hit the area over a 10-day 

period in early January 1997. 


51 

The five field investigations of the Karito Canal dieback zone, covering a 20-month period, 

showed a steady recovery of some almost totally defoliated (and partially dead) mangroves, 

as well as considerable revegetation (photos 2 and 3, Figure 5.4). 

In October 1999, there were a combined total of 25 live trees and 96 dead trees, and no 

seedlings, from three random 2 x 2 metre plots. This gave an average of 2.1/m 2 and 8.0/ m 2 , 

respectively. All of the “live” trees were either saplings less than one metre in height or 

partially dead trees with many brittle branches. About 40% of the surface area of the upper 

half of all the trees – alive, dead, and partially alive – was covered in lichen. There were no 

obvious crab (Helice crassa) holes, but this may be due to persistent heavy rain at the time, 

falling onto the exposed holes and collapsing them (Kala Sivaguru, personal communication, 

2001). Neighbouring plots in the healthy mangrove zone had an average of 76 crab holes per 

m 2 , and the average for the dredge spoils area (also receiving direct heavy rain) was 18 per 

m 2 . This may be an indication that some characteristic of the soil in the dieback area was 

undesirable for both mangroves and crabs. 

In October 2000, six randomly chosen 2 x 2 m plots within the main dieback area (about 50 x 

60 m) yielded 54 live trees (including saplings), or 2.25/m 2 , with an average height of 108 

cm. Of these 54, fifteen were in recovery (heights of greater than 135 cm). There was an 

equal number of dead trees (53). There were 26 seedlings, an average of slightly more than 

one per m 2 . Perhaps the most striking information from this data set is the density of crab 

holes: 212.3 per m 2 , counted from 24 x ¼ m 2 quadrats. 

By July 2001 (photo 3, Figure 5.4), the number of saplings and seedlings had greatly 

increased, most of the severely affected trees that showed minimal sign of life in October, 

1999 had recovered (though many dead branches remained), and the crabs had placed their 

stamp of approval on the habitat. Many of the dead trees and branches had broken up through 

wind, and wave action and disturbance by keen young scientists. 

It is particularly significant that, while there was some new leaf growth on the trees in the 

dieback zone in October 1999, the process of recovery was very slow. It started to pick up 

speed by March 2000 (photo 2, Figure 5.4), with the appearance of some seedlings, crab 

holes, and more regrowth on the stressed trees, but it was not until October (about 34 months 

after the dieback event was documented) that recovery seemed to be assured (and confirmed 

during the July 2001 visit). By December 2004 the dieback area had mangrove coverage that 

was equal to the high density of the unaffected area just beside it (photo 2, Figure 5-6, to the 

right of the lower trees covering the spoils area). 

Evidence of the extensive 1997 dieback area on the right bank near the mouth of the 

Waitakaruru River was almost non-existent in December, 2004. Only a few dead stems 

remained in an area of very dense regeneration consisting mainly of mature trees 1.0 – 2.5 m 

high. 

A significant new die-off area just W of the Piako River mouth was noticed at a distance from 

the sea in December, 2004. These were mainly tall trees about 100 m inland from the current 

leading edge of young mangrove forest, and one large grouping of them still were covered in 

dead leaves. 

5.8 Effects of Frost 

There has been considerable discussion about both the frequency and intensity of frosts as 

limiting factors to the survival of mangroves in places where they are close to the apparent 

limits of their range, and –2.2°C is frequently cited as a lower limit for their survival (de 


52 

Lange and de Lange, 1994). However, frosts of this magnitude do occur throughout the 

Ramsar Site, and several occurred in the winters of 1997 and 2001. 

Keeping in mind the possibility that such frost, particularly over a prolonged period (such as 

the estimated eight that occurred over a three week period in 2001), might be a significant 

stress factor for mangroves, we surveyed the Karito Canal on July 26 just after the heaviest of 

the 2001 frosts. We found some small groupings of seedlings (especially those more than 

three metres distant from the water’s edge) were completely dead from recent frostbite. One 

grouping of 15-30 cm seedlings in an area of 1.5 m 2 opposite the floodgate contained 22 

completely dead individuals, 47 severely browned, and 22 that were ensconced amongst some 

dense Sarcocornia and unaffected by the frost. 

In the same area, at the top of the bank of the Canal, there were six young trees about 1 m in 

height that had a few new leaves that were browned around the edges, but otherwise showed 

no signs of stress. Lower leaves of trees, and seedlings that had been bathed by the tide and 

had a coating of mud on them, were unaffected. Most of the fully mature trees throughout the 

system were not damaged at all, except by browning of the edges of the tenderest leaves, and 

by some brown spots that appeared to be where water droplets had been sitting when the frost 

hit. 

There were some mangrove shrubs (1-2 year-olds), particularly those out in the open in slight 

hollows away from the Canal, that had serious frost damage to the majority of their leaves, 

but these cases were represented by only about twelve plants. 

It appears that frost on the order of -2 ºC does not kill mature mangroves, even when it 

happens on successive nights. However, it may weaken their resistance to other 

environmental factors such as the leafroller caterpillar, seen in small sizes and numbers on 

this visit. There were no caterpillars in evidence on our June 20 visit. 

5.9 Conclusions 

Mangroves in the Firth of Thames provide a valuable buffer to the entire coastline of the Firth 

of Thames Ramsar Site, except for the part between the Miranda Stream and Kaiaua, which is 

protected by the continuing formation of Chenier ridges. In fact, mangroves are accelerating 

the filling-in process of the upper Firth through the entrapment of sediments by their 

pneumatophores, roots, and the algae and debris that collect around them. The rate of 

acceleration seems to be increasing, due to elevated levels of sediments still being produced 

mainly through agricultural, drainage maintenance and housing development activity in the 

catchment, and the rapidly expanding amount of mangrove surface area at or near the 

substrate of the intertidal zone. 

Mangroves are effective in maintaining channels of rivers and drains that flow through the 

intertidal area. They create an outlet, with heavily vegetated banks, that flushes naturally, 

except when there is a build-up of shell, live oysters and/or debris barriers within them. The 

Piako River, historically the second swiftest and deepest of Firth of Thames tributaries (and 

thus highly navigable) is now experiencing extensive build-ups of oyster beds in the river 

mouth that already impede the movement of small boats at lower levels of the tide (P. 

Thorburn, personal communication 2004). 

Occasionally some maintenance dredging needs to be applied to parts of the channel system, 

particularly after long periods without flushing by severe storms and floods. When dredging 

is considered necessary in intertidal channels, it could alternatively be done by barge-mounted 

suction dredges, and the spoils barged away. This is a very costly process, and still leaves the 


53 

issue of proper disposal, whether at sea or on land to be resolved, since the rate of sediment 

build-up in the drainage systems is increasing (S. Clark, personal communication 2004). 

In Whangamata and a few other enclosed harbours, some residents and visiting boating 

people are worried that the natural expansion of mangroves (and few limiting factors to hold 

them back) are intercepting more and more of the sediments coming off the land, and turning 

places habitually used by people for recreation and sheltering their boats into naturallyproduced 

landfills. This is not yet a serious problem in the area of the Ramsar Site, as tidal 

and freshwater flushing (assisted by the straightening works of the 1920s and 30s) in the three 

rivers active with boating traffic has protected them from significant sediment build-up so far. 

The Firth of Thames mangroves are a cornerstone of the ecosystem, particularly as habitat for 

a diversity of marine and avian species, and as a source of food and nutrients for the estuarine 

food web. In the case of the expansion of lagoon fringe mangroves in vital shorebird roosting 

areas at Miranda, it may be necessary to find a means control them. 

Now, at the end of 2004, there is increasing evidence that this is truly a new ecosystem in the 

making, with potentially significant implications for the ecology of the entire Firth of 

Thames. Valuable new habitat is being created. Old and new marine species experiencing 

increased survivability due to vital sheltering, food supply and reproductive success factors 

are thriving. 

While there are some small harbours in areas of heavy use by humans in which mangroves 

may need to be controlled, it must be understood that the advancement of mangroves is a 

natural ecological response to changing environmental conditions, most of them precipitated 

by humans. As long as we continue to cause excessive amounts of sedimentation in the 

coastal zone, mangroves will continue to march into it. Burns (2003) cites the endemic 

organisms that depend on Avicennia, and the ecosystem services and biodiversity values that 

mangroves provide in calling for objective and informed management decisions. 

An apparent decrease in biodiversity caused by the great increase in sedimentation over the 

past 50 years may now be on the increase again as the system adjusts to the new dominance 

by mangroves. This may, in fact, prove to be of long-term value to the Firth of Thames 

ecosystem. It is imperative to redouble our efforts to assign protective status to this area, and 

to carry out regular scientific observations to document the whole process before we make 

any hasty judgments about an ecosystem in the making. 


54 

6 Birds of the Miranda Coast 

by Ria Brejaart, Peter Maddison and Phil Battley 

At the height of migration they arrive in flocks that at times seem to fill the sky. They spread 

out as they land, bills probing almost before their feet touch the ground. They stitch the mud 

again and again at low tide, turning the seemingly inexhaustible invertebrate inventory into 

shorebird tissue. They refuel for some days and then, swaddled in sustaining fat, are on their 

way again to north or south. - Dennis Paulson (quoted in Barter, 2002). 

6.1 Introduction 

New Zealand has a number of important estuarine feeding and roosting grounds frequented by 

migrant waders and shorebirds (Fig. 6.1). Along with Kaipara Harbour, Manukau Harbour, 

Farewell Spit and Lake Ellesmere, the Firth of Thames is one of the localities for waders and 

shorebirds considered to be of outstanding importance in the New Zealand context (Medway 

2000). 

The Firth of Thames hosts significant numbers of various indigenous New Zealand migrants. 

It is also one of the terminal points of the East Asian-Australasian Flyway used by about five 

million shorebirds that migrate annually (between July and October) from Siberia and Alaska 

for summer in the southern hemisphere, and return between March and June to their northern 

breeding grounds (Barter 2002). 

Many estuaries around the world of critical importance to these birds are already severely 

encroached upon by urban development, and/or face increasing pressures from human 

activities and land use in the surrounding catchments. Twice a year the international migrants 

using the East Asian-Australasian Flyway pass over some of the densest human populations 

in the world, and the wetlands and estuaries in East Asia that they habitually use along the 

way for feeding and resting are increasingly threatened by human occupation and use. 

6.2 Birds of Miranda and the Firth of Thames 

The stretch of coast between Taramaire and the Pukorokoro (=Miranda) Stream (Figures 6.2 

and 6.3) is the most important shore bird area of the Firth of Thames. The Stilt Ponds, 

situated at the southern end of the area, are part of the Robert Findlay Wildlife Reserve, 

which is private property, subject to a Queen Elizabeth II National Trust covenant. The Stilt 

Ponds provide food for many waders, particularly pied stilts (Himantopus himantopus), 

banded dotterels (Charadrius bicinctus), wrybills (Anarhynchus frontalis) and sharp-tailed 

and pectoral sandpipers (Calidris acuminata & C. melanotus). These pools are also attractive 

as a high-tide roosting site for many bar-tailed godwits (Limosa lapponica) and lesser knots 

(C. canutus). Large flocks of wrybills frequently roost along the Stilt Pond margins and the 

shellbanks adjacent to the Robert Findlay Wildlife Refuge and the Taramaire Stream mouth, 

and at times roost elsewhere along the Miranda Coast as far north as Kaiaua. A shellbank just 

offshore from the Robert Findlay Wildlife Refuge is an important roost site for waders, gulls 

and terns on neap tides. A large area of mudflats near the old limeworks site is periodically 

an important roosting place for flocks of bar-tailed godwits, lesser knots, South Island pied 

oystercatchers (Haematopus finschi) and pied stilts (Hay 1983). 

Important roost sites for birds on the eastern shores of the Firth of Thames are located at the 

mouth of the Waihou River (South Island pied oystercatcher, wrybill, bar-tailed godwit and 

lesser knot) and north of Thames at Tararu (pied oystercatcher). 


55 

Figure 6-1 Important Sites for waders and shorebirds in New Zealand (indicated by bold 

italics) 

Taken from: Medway 2000. Reprinted by permission 


56 

Several species of Arctic wader were first recorded in New Zealand on the Miranda coast or 

the Firth of Thames. Amongst the impressive list of ‘first occurrences’ are grey plover 

(Pluvialis squatarola) (1948), terek sandpiper (Tringa terek) (1951-2) and eastern broadbilled 

sandpiper (Limicola falcinelus sibericus) (1960). The first certain Asiatic black-tailed 

godwits (L. limosa) recognized in New Zealand were seen in 1955-6. The second Asiatic 

dowitcher (Limnodromus semipalmatus) to be recorded in New Zealand was seen associated 

with a flock of bar-tailed godwits on the Miranda coast in 1987 (Medway 2000). 

Figure 6-2 Wader habitats at Firth of Thames Ramsar Site 

Adapted from: Veitch, C.R. and A.M. Habraken. 1999. Waders of the Manukau Harbour and 

Firth of Thames. Notornis 46:45-70. Modified and reprinted by permission. 


57 

Figure 6-3 Changing habitats at Miranda 

(adapted from Veitch and Habraken 1999, reprinted by permission). 


58 

The value of the coastal area as a site for waders along the East Asian/Australasian Flyway is 

now well documented. The Ramsar Site provides not only habitat for the waders, but an array 

of wetland and estuarine habitats for many other coastal birds. The shellbanks of this area 

provide vital roosting sites for large numbers of shore birds, but are also important as 

breeding sites for up to 1000 pairs of white-fronted terns (Sterna striata) at Taramaire, blackbilled 

gulls (Larus novaehollandiae) and a few pairs of the endangered northern New Zealand 

dotterel (C. obscurus aquilonius). The "dryland" habitats, with the marshy hollows and 

weedy inland shell banks, provide a further series of habitats for birds of open habitats. Some 

grassy coastal areas, which have formed as a result of mangrove advancement, are now used 

as nesting sites for black-backed gulls (Larus dominicanus). 

Bird census data in New Zealand have been well documented since 1960, giving New 

Zealand a good ranking internationally in terms of the extent of historic data on bird 

populations. An excellent selection of research papers on waders is given in “Wader Studies 

in New Zealand”, a special memorial issue of Notornis (Volume 46, Part 1, 1999). 

Twice yearly (summer & winter) wader counts between 1960 and 1998 (38 x 2) confirm the 

importance of the Firth of Thames habitat, and particularly the Ramsar Site (Sagar et al. 1999, 

Veitch & Habraken 1999, Medway 2000). Irregular counts were also carried out in the period 

1951-59, but these data are not accurate for comparative purposes, and have not been 

included. The cycle continues without interruption, and an updated analysis will be achieved 

in 2005. 

The winter counts were done between 17 May and August 1 st , and the summer ones between 

18 October and 22 December (variable from year to year). Counts were coordinated among 

observer groups to assure that multiple countings of the same birds did not occur. Data was 

analysed by using the Mann-Whitney U test or Kruskal-Wallace one-way analysis of 

variance, supplemented by Dunn’s method of multiple comparison between decades (Veitch 

& Habraken 1999). Average numbers of birds per period are presented as a mean ± standard 

deviation (SD). 

The Firth is particularly notable for the following: 

• Over this period, the Firth of Thames supported a larger winter population of wrybills 

than any other locality. Each winter the population averages 2140 birds. This has 

been estimated as 58.5 % of the New Zealand (= world) population 

• The Firth of Thames was one of the top two sites in the country (along with the 

Manukau Harbour) for pied stilts in winter. From 1990 to 1998, average winter 

population in the Firth of Thames was 4134 ± 1326 birds. Summer numbers of pied 

stilt averaged about 700 (1983-1994) 

• Winter numbers of South Island pied oystercatcher for 1990-98 were 17,834 ± 6610 

birds, second only to the Manukau Harbour and similar to the population in the 

Kaipara Harbour 

• From 1983 to 1994, the Firth of Thames was one of the top five sites in New Zealand 

for lesser knot in summer (with 1900-5200 birds recorded). In winter, the Firth 

ranked third in the country (on average 506 birds, or 10% of the national population). 

• From 1983 to 1994, the summer counts of curlew sandpiper (C. ferruginea) averaged 

fifteen, equivalent to the Parengarenga Harbour and second only to Lake Ellesmere as 

a site for this wader. 


59 

• Over 1983-1994, rarer waders that favoured the Firth of Thames during summer were 

sharp-tailed sandpipers (average 13/year) and whimbrels (Numenius phaeopus) 

(average 19/year). 

Waders have been banded in New Zealand since the 1970s, under a regular schedule by the 

New Zealand Wader Study Group since the late 1980s. In the 1990s, the addition of regional 

coloured leg-flags to the banding work greatly increased the number of international 

resightings of migratory waders. New Zealand-banded lesser knots have been seen in 

Australia, Irian Jaya, Taiwan, South Korea, China and Russia, while birds seen in New 

Zealand have included birds caught in Australia, China, South Korea and Japan. Bar-tailed 

Godwits have been seen in China, South Korea, Japan, Russia and Alaska; resightings or 

recaptures the opposite direction have come from Australia, China and Alaska. 

A summary of relevant information about the more common species, and brief notes, by 

family, on the less common species is given in sections 6.3 –6.4. 

6.3 Survey of the foreshore between Tararu and Hot Springs Drain 

Historically, shorebirds were recorded roosting at high tide across much of the southern Firth 

of Thames (OSNZ surveys, unpubl. data). However, habitat changes over recent years have 

greatly modified the nearshore landforms and vegetation across the southern edge of the Firth. 

Accordingly, a pilot survey of the foreshore of the southern Firth of Thames (Tararu to Hot 

Springs Drain) was carried out in 1998 and 1999. The main focus was on broad vegetation 

types previously described in this report (Chapter 3) and available habitat types for waders 

and shorebirds. Observations on birds made during this survey are summarized below 

(abundant = found at several locations in large numbers; common = frequently sighted, but in 

lesser numbers; ( ) = actual numbers seen. 

6.3.1 Tararu Creek – Kopu Bridge (January 1999) 

Just north of Tararu are breeding colonies of pied shags (Phalacrocorax varius), white 

fronted terns and red-billed gulls (Larus novaehollandiae scopulinus). 

At the northern end of Tararu, there is a small reserve with large pohutukawa and grassed 

areas. South Island pied oystercatchers (SIPO), and mallards (Anas platyrhyncos) were 

observed roosting there in small numbers. At high tide, there is no beach habitat for roosting 

or feeding along the Tararu foreshore. The only open habitat adjacent to the beach is at 

Moanataiari. The area is used intensively as a high tide roost by large flocks of SIPO. At the 

old wharf at Moanataiari white-fronted tern (100), pied shag (4), and black-backed gull 

(Larus dominicanus) (4) were seen roosting and feeding. 

At low tide, the exposed mud (and to a lesser degree the fringes of the mangroves) affords 

feeding habitat for a number of wader species and shorebirds. Species observed include 

white-faced heron (Ardea novaehollandiae) (2), bar-tailed godwit (abundant), black-backed 

gull (6), pied stilt (common), mallard (common), red-billed gull (abundant) and SIPO 

(abundant). 

Birds observed utilising the mangrove areas included numerous house sparrows (Passer 

domesticus), and low numbers of welcome swallow (Hirundo tahitica neoxena), blackbird 

(Turdus merula), myna (Acridotheres tristis) and mallard. 

Large open spaces such as a building site in Thames and paddocks south of Thames attracted 

several hundred SIPO at high tide. 


60 

South of the Kauearanga River, pukeko (Porphyrio porphyrio melanotus) and paradise ducks 

(Tadorna variegata) were common. The sandbank at the mouth of the Waihou River was 

used as a roost site by black-backed gull, white-fronted tern and bar-tailed godwit. SIPO, 

wrybill, pied stilts and lesser knot are also known to roost there, while black-billed gull, New 

Zealand dotterel, variable oystercatcher (Haematopus unicolor), white-fronted tern and 

Caspian tern (Sterna caspia) all nest there. 

6.3.2 West bank of the Waihou River to East bank of the Waitakaruru 

River (September 1998) 

This section of the coast is characterised by extensive and near continuous areas of 

mangroves (up to 500 m wide at the mouth of the Waihou River) and glasswort salt marsh. 

Bird species seen on this section included: 

Spur-winged plover (Vanellus miles novaehollandiae) (1); black shag (Phalacrocorax carbo 

novaehollandiae) (12); Australasian harrier (Circus approximans) (3); pukeko (3); mallard 

(5); paradise duck (6); cattle egret (Bubulcus ibis) (45); black-backed gull (4); house sparrow 

(7); yellowhammer (Emberiza citronella) (5), white-faced heron (1). Birds heard: chaffinch 

(Fringilla coelebs); grey warbler (Gerygone igata). 

Dense stands of mature mangroves (mainly 3-5 m in height) line the mouth of the Piako 

River, starting just north of the Pipiroa Bridge and continuing along the coast in either 

direction (see Chapter 3). Birds observed included: pied stilt (5); white-faced heron (3); SIPO 

(6); kingfisher (Halcyon sancta) (2); mallard (6 fledglings); welcome swallow, spur-wing 

plover, Australasian harrier, myna, magpie (Gymnorhina tibicen), yellowhammer, black shag, 

black-backed gull and paradise duck (all occasional); pukeko (abundant). Two pukeko nests 

were seen, but they were not in use. 

6.3.3 Hot Springs Drain to Waitakaruru (November 1998) 

Extensive and near continuous mangals occur along this coast. Sarcocornia salt marsh 

interspersed with bachelor's button and salt marsh ribbonwood dominates large areas 

landward of the mangal. Black-backed gulls were the most abundant bird in this area. 

Thrity-eight individuals were seen, and seven nests (five nests with three eggs, and two with 

two eggs in them) were found between the pump station and the Karito Canal. White-faced 

herons were also abundant, and pied stilts were common. 

6.4 Principal Waders 

Family: SCOLOPACIDAE 

Lesser knot, red knot – Calidris canutus 

Knots are the second-most numerous Arctic-breeding wader in New Zealand, with a 

population of around 59,000 estimated from annual OSNZ summer censuses (Sagar et al. 

1999). Numbers have declined gradually in the Firth of Thames from 5758 (±2355) in 1960- 

69 to 3672 (± 1712) in 1990-98 (Veitch & Habraken 1999). Over-wintering numbers 

averaged 447 birds in the period 1990-98 (Veitch & Habraken 1999), but the SD of ± 592 

makes this figure questionable . 

Lesser knot feed in large, dense flocks, often close to the tideline. They feed with a 

characteristic ‘sewing’ action that uses a pressure-sense to detect buried objects (Piersma et 

al. 1998). The diet of knots almost invariably is dominated by bivalves (e.g. Piersma et al. 

1993, Zwarts and Blomert 1992), and this is true for New Zealand too. In the Firth of 


61 

Thames, knots have been recorded feeding on the small bivalves Austrovenus stutchburyi, 

Nucula hartvigiana, Macomona lilliana and Myadora boltoni (Piersma 1991, P.F. Battley, 

unpubl. data). On Farewell Spit, a more thorough examination of the diet recorded mostly 

small bivalves (particularly Paphies australis in sandy areas and Nucula hartvigiana and 

Austrovenus stutchburyi in Zostera (eelgrass) beds) but also small gastropods and, where prey 

densities were high enough, small amphipods and isopods (Battley 1996). Because the sizes 

of bivalve prey can be reconstructed from measurements of hinge remains in droppings 

(Dekinga and Piersma 1993), the size-distribution fed upon taken can be determined far more 

accurately than for birds feeding on soft-bodied prey. On Farewell Spit, knots fed upon 

Paphies australis

62 

Family: RECURVIROSTRIDAE 

Pied stilt, black-winged stilt – Himantopus himantopus 

The New Zealand populations of this widespread wader bird belong to the subspecies 

leucocephalus. There is some hybridisation with the endangered endemic black stilt, 

Himantopus novaezelandiae. Pied stilts breed throughout New Zealand in loose colonies of 

three to twenty pairs and, occasionally, up to 100 pairs. They nest on mounds, often 

surrounded by water, in wetlands, muddy pasture and at the edges of ponds, streams and 

estuaries. Summer counts have varied from 1126 ± 777 birds in 1970-79 to 629 ± 453 for 

1990-98. Corresponding winter counts were 2837 ± 1242 and 4134 ± 1326 birds. 

Stilts are found in areas of shallow water (such as the Miranda Stilt Ponds) and in ploughed 

paddocks and grassland. The most favoured paddocks are those where cattle are present, 

disturbing the ground. The stilt’s long beak is used to skilfully probe for food in shallow 

water or soft ground. On ponds and rivers, insects make up much of the diet (see below); 

nothing is known of what stilts feed upon in soft mud in the intertidal zone such as in the Firth 

of Thames. 

A study in Manawatu identified the following invertebrates as food: Potamopyrgus 

(Gastropoda) and other molluscs; ostracods (Crustacea) and many insects – larvae of Odonata 

(damselflies), Diptera (flies) - principally Chironomidae (midges), Trichoptera (caddis-flies), 

and adults of Coleoptera (beetles) and Hemiptera (bugs) (McConkey 1971). 

A study of faecal samples and of stomach contents from birds in the Cass River Valley 

recorded Oligochaeta (worms), molluscs (including Potamopyrgus), Hydracarina (watermites), 

Corixidae and Notonectidae (water-boatmen), Diptera and Hymenoptera (wasps) 

adults and a large number of larvae of Chironomidae (midges) (Pierce 1982). 

Family: CHARADRIIDAE 

Northern New Zealand dotterel – Charadrius obscurus aquilonius 

This is an endemic species, which nests on sand spits, beaches, shellbanks and similar areas, 

with little vegetation. Numbers from the OSNZ censuses (1990-98) are 10 ± 6.6 (summer) 

and 21 ± 12 birds (winter) (Veitch & Habraken 1999). Birds forage over a range of habitats 

and are commonly seen in tidal estuaries, feeding on the mudflats, and on sandy beaches. The 

feeding behaviour is that of a typical plover: short runs interspersed with ‘walk-stop-peck’ 

sessions. The diet consists mainly of invertebrates, including crabs and sandhoppers, and 

occasionally small fish, (Heather and Robertson 1996). They also feed on insects and were 

reported “eating the tips of glasswort [Sarcocornia] plants” (Medway 2000). 

Banded dotterel – Charadrius bicinctus 

This species is endemic to New Zealand as a breeding species but much of the population 

migrates to Australia in the winter (Pierce 1999). There are also regular records from Norfolk 

and Lord Howe Islands, and vagrants have reached Fiji, Vanuatu and New Caledonia 

(Marchant & Higgins 1993). The OSNZ censuses record 89 ± 66 (winter) and 2 ± 2.1 

(summer) for the years 1990-98. The birds in winter are found in a range of habitats from 

pasture and arable land to estuarine mud flats. Their feeding activity is described as ‘run- 


63 

stop-peck’. On pasture they feed on earthworms and beetles; in marshes and similar 

freshwater muddy areas (e.g. the Miranda Stilt Ponds), they feed on insects (such as 

Chironomid midge larvae) while on the tidal mud flats they eat annelid worms (Heather & 

Robertson 1996). They are reported to eat the berries of prostrate plants (Medway 2000). 

Banded Dotterels formerly bred along the shores of the Firth of Thames but no longer do so. 

Wrybill – Anarhynchus frontalis 

This endemic plover nests in Canterbury and inland Otago on the upper reaches of the braided 

rivers. After breeding the majority of the population flies north to winter on the large tidal 

harbours around the Auckland region (Kaipara Harbour, Manukau Harbour and the Firth of 

Thames). The Firth of Thames is the traditional wintering site for the species, with winter 

census counts of 3342 ± 1705 from 1960-69)and 2230 ± 1509 birds from 1990-98. The total 

population over those periods was estimated at 5000 to 7000 birds, so around one third to a 

half of the wrybill population occurred in the Firth. In recent years numbers at the Firth have 

declined slightly while numbers in the Manukau Harbour have increased; it is not known why 

this change has happened. Recent estimates put the total population at 4500-5000 birds 

(Riegen & Dowding 2003). Few birds remain in the Firth over summer; comparative summer 

census figures are 97 ± 68 and 48 ± 26 birds. 

Wrybills roost gregariously on shellbanks, sandbanks and in the shallow water of the Miranda 

Stilt Ponds. They feed actively on soft mud at the edge of the receding tide and over the soft 

“green” mud areas at Miranda. Birds hunt across the mud, probing for worms and catching 

“small crustaceans by scything the wet mud, the bill dabbing slightly from left to right.” 

(Heather and Robertson 1996). The diet on the mudflats has been little studied: Turbott 

(1970) and Keeley (1985) both noted annelids. 

Wrybill resting near shellbank by Miranda Stream (photo K. Woodley) 

Spur-winged Plover, Masked Lapwing– Vanellus miles novaehollandiae 

This plover is distributed widely in Australasia (from Australia, Papua New Guinea and New 

Zealand). Its colonisation of New Zealand is relatively recent, the first pair nesting in 

Invercargill in 1932. Since then, it has spread throughout New Zealand, colonising the Firth 

of Thames area in the late 1980s. It is noteworthy that Bacon’s (1975) report on coastal 


64 

ecology does not mention this bird. This plover has become a common resident of arable and 

pasture habitats. It is common in the Miranda coastal strip, recognised by its staccato ‘rattle’ 

call (by day or night) – a call that alerts other birds to the presence of visitors (and 

consequently an annoyance to serious birdwatchers). 

These plovers walk slowly over the ground; they feed on earthworms, insect larvae and 

adults, seeds and other plant material. In coastal and tidal areas, they feed on crustaceans and 

molluscs (Heather and Robertson 1996). 

Family: HAEMATOPODIDAE 

SIPO (South Island Pied Oystercatcher) – Haematopus ostralegus 

This oystercatcher has an almost worldwide distribution; however, some authors treat the 

New Zealand subspecies, ssp. finschi as a distinct species. This oystercatcher breeds on the 

braided riverbeds, farmland and lake margins of the South Island and at a few North Island 

sites. After breeding, some birds go to South Island estuaries, but in summer most birds 

migrate to North Island estuaries and sandy beaches. Results of OSNZ censuses have 

demonstrated a significant increase in oystercatcher numbers. Winter counts have been 1523 

± 927 (1960-69) and 17834 ± 6610 birds (1990-98). Comparable summer numbers are 244 ± 

147 and 3027 ± 1309 birds (Veitch & Habraken 1999). This increase is also evident in 

national censuses or estimates: in 1970/71 the population was estimated at 49 000 birds, while 

in 1994 112 000 were estimated (Sagar et al. 1999). 

Oystercatchers feed on sandy shores and on exposed mud in estuaries, and in ploughed or 

grazed paddocks, particularly in winter paddocks. Birds may leave the tidal flats as the tide 

comes in and move to paddocks over the high tide period when fields are wet, returning to the 

tidal flats once the tide has receded. Birds may also continue to feed on paddocks throughout 

the low tide period if conditions are good. Being large birds that feed on large prey, 

oystercatchers typically feed for shorter periods than other waders (Battley 1996), so may not 

start to feed until the low to mid-tidal shore is exposed. They feed by surface picking or 

probing deep into the mud. Their diet consists mainly of molluscs (especially bivalves), 

annelids, sea anemones and, occasionally, small fish; on shore, earthworms and insect larvae 

are taken. Amongst the species recorded as prey are Glycera americana, Nicon aestuariensis, 

Abarenicola affinis and Maldanid bamboo worms (Polychaeta), the mud snail, Amphibola 

crenata, the common mud whelk, Cominella glandiformis, cockle (Austrovenus stutchburyi), 

pipi (Paphies australis), tuatua (Paphies subtriangulatum), large wedge shell (Macomona 

liliana), small black mussel Xenostrobus pulex, sandhoppers (Talorchestia), burrowing mud 

crab (Helice crassa), shrimp (Palaemon) and juvenile sand flounder (Rhombosolea plebeia) 

(Marchant & Higgins 1993, Battley 1996). 

Variable Oystercatcher – Haematopus unicolor 

An endemic New Zealand species, which breeds in the northern part of the Firth of Thames 

and at Taramaire and near the mouth of the Waihou River. Numbers in OSNZ censuses 

indicate an increase from 2.44 ± 3.52 (1960-92) to 33.67 ± 22.55 (1993-98) (Veitch & 

Habraken 1999). The birds feed mainly on rocky shores, so are commonest in the Firth 

around Kaiaua, though they are also found on sandy shores or estuaries. The diet consists of 

mainly molluscs, especially bivalves, crabs and annelid worms. Other small invertebrates and 

occasionally small fish are eaten (Heather & Robertson 1996). 


65 

6.5 Other Wader Species 

As in other major bird areas, there is a large list of other species infrequently seen or present 

in small numbers in the Firth of Thames. None are likely to have a major impact on the 

ecology. These are listed in Appendix Table 3.1. Their occurrence is summarized below. 

Information is chiefly from OSNZ censuses, summarized by Veitch and Habraken (1999). 

Family : SCOLOPACIDAE 

Asiatic black-tailed godwit - Limosa limosa Highest counts from the census are 11 

(summer) and 2 (winter). 

Hudsonian godwit - Limosa haemastica Very rare vagrant. 

Little curlew, Little whimbrel - Numenius minutes Very rare vagrant. 

Whimbrel - Numenius phaeopus Uncommon and irregular migrant. Census counts are 14 ± 

10.2 (summer) and 1 ± 1.3 (winter) (1990-98). 

Eastern curlew - Numenius madagascariensis Uncommon but regular migrant. Census 

counts are 15 ± 8.8 (summer) and 4 ± 3.2 (winter) (1960-69). 

Marsh sandpiper - Tringa stagnatalis Highest census counts are 3 (summer) and 4 (winter). 

Common greenshank - Tringa nebularia Very rare vagrant. 

Terek sandpiper - Xenus cinereus Highest census counts are 3 (summer) and 2 (winter), 

Common sandpiper - Actitis hypoleucos Very rare vagrant. 

Siberian tattler, Grey-tailed tattler - Heteroscelus brevipes Very rare vagrant. 

Wandering tattler - Heteroscelus incanus Very rare vagrant. 

Asiatic dowitcher - Limnodromus semipalmatus Very rare vagrant. 

Great knot - Calidris tenuirostris Very rare vagrant. 

Sanderling - Calidris alba Very rare vagrant. 

Western sandpiper - Calidris mauri Very rare vagrant. 

Little stint - Calidris minuta Very rare vagrant. 

Red-necked stint - Calidris ruficollis Uncommon and irregular migrant; numbers 

apparently declining in recent years. Census counts are 9 ± 5.9 (summer) and 2 ± 3.8 (winter) 

(1960-69). 

Bard’s sandpiper - Calidris bairdii Very rare vagrant. 

Pectoral sandpiper - Calidris melanotos Very rare vagrant. 

Sharp-tailed sandpiper - Calidris acuminata Highest census counts are 40 (summer) and 

12 (winter). 

Dunlin - Calidris alpina Very rare vagrant. 

Curlew sandpiper - Calidris ferruginea Uncommon but regular migrant. Census counts 

are 16 ± 10 (summer) and 3 ± 10 (winter) (1980-89). 

Broad-billed sandpiper - Limicola falcinellus Very rare vagrant. 

Red-necked pharalope - Phalaropus lobatus Very rare vagrant. 

Family : RECURVIROSTRIDAE 

Black stilt - Himantopus novaezelandiae Very few black stilts (an endangered New 

Zealand endemic species) have been recorded in the Firth of Thames. The average number for 

winter (1990-98) was 1.3 ± 1.2. 

Family : CHARADRIIDAE 

Black-fronted dotterel - Charadrius melanops Very rare vagrant. 

Ringed plover - Charadrius hiaticula Very rare vagrant. 

Large sand dotterel - Charadrius leschenaultii Very rare vagrant. 


66 

Mongolian dotterel - Charadrius mongolus Very rare vagrant. 

Oriental dotterel - Charadrius veredus Very rare vagrant. 

Pacific golden plover, lesser golden plover - Pluvialis fulva Numbers of this summer 

visitor vary from year to year with a decline from 46 ± 45 (1960-69) to 3 ± 4.7 (1990-98) 

(Veitch & Habraken 1999). 

Grey plover - Pluvialis squatarola Very rare vagrant. 

6.6 Wetland Birds and Waterfowl 

Family : ARDEIDAE 

White-faced heron - Ardea novaehollandiae 

This is a widespread Australasian species, migrating to New Zealand between 1865 and the 

1930s and then establishing itself. These herons nest high up in trees, such as pines or 

macrocarpas. 

This heron forms loose flocks or may feed alone on the mud flats and across the shell banks 

and small tidal creeks. The diet includes fish, frogs, pasture and aquatic insects and 

earthworms, (Heather & Robertson 1996). 

White heron - Egretta alba 

This species has a worldwide distribution, but in New Zealand it is a rare species, nesting 

only at Okarito in Westland. In recent years, one to a few birds have been seen at Miranda, 

frequenting the mud flats and tidal estuaries. The food includes fish (including eels), frogs, 

shrimps and freshwater aquatic insects, (Heather & Robertson 1996). 

Little egret - Egretta garzetta 

An occasional migrant, found in tidal estuaries and wetlands. They actively feed on fish. 

Reef heron - Egretta sacra 

This heron is found along rocky shores and tidal estuaries with mangroves. They feed on fish, 

crabs and molluscs, (Heather & Robertson 1996). 

Cattle egret - Bubulcus ibis 

This egret is a winter visitor, which visits swamps and pasture, and is often associated with 

cattle or sheep. They feed on earthworms, insect larvae, crickets, grasshoppers and flies. 

Australasian bittern, Matuku - Botaurus poiciloptilus 

This is a rare indigenous wetland bird, inhabiting swamps and other coastal waterway areas, 

with tall vegetation. They feed on fish, frogs and freshwater insects and crustaceans. 

Family : THRESKIORNITHIDAE 

Glossy ibis - Plegadis falcinellus Very rare vagrant 

Royal spoonbill - Platalea regia A regular winter visitor in small numbers - often parties of 

5-6 are seen in winter months. 

Family : ANATIDAE 

Mallard - Anas platyrhynchos 

This introduced duck is common in wet grassy areas, wetlands and estuaries. Occasional 

groups occur in the intertidal area along the Miranda-Kaiaua coast. Numbers of mallard have 

declined in recent years through habitat loss; it is believed that hybridization and competition 

with the grey duck has resulted in serious decline of the latter species. Mallards nest in tall 

grass or dense vegetation near water. The nest may be in a hollow tree or in a depression in 

the grass. The usual size of the clutch is 10-16 eggs, laid from late July through to October, 

with re-nesting up until the end of December or even later. The diet consists principally of 

aquatic vegetation from shallow water - either by dabbling or by "up-ending". On land they 


67 

graze on grass and other low-growing plants, showing a preference for seeds (grain) and 

fruits. Young birds and pregnant female ducks also feed on invertebrates, particularly small 

snails, water beetles and insect larvae. After floods, they feed on drowned earthworms, etc. 

In May 1998 over 200 mallards were observed (on two occasions) along a 2 km. stretch of 

mangroves on both sides of the Waitakaruru River. Many of these birds were dead or dying. 

At about the same time, a local farmer and a DoC field officer counted over 1000 dead ducks 

in the general area of the Waitakaruru River mouth, and another 300 in the mangroves beyond 

the stop bank, 1 km. east of the River (Bert Laing, pers. comm.). This event occurred soon 

after an extremely dry summer and autumn - the cause was determined to be botulism (Tony 

Roxburgh, pers. comm.). 

Grey Duck - Anas superciliosa 

This indigenous duck has declined in the past few decades. The reasons for this decline have 

been attributed to habitat loss and to loss through hybridization and competition with the 

mallard. Grey ducks are found near small lakes, in tidal waters and along slow flowing rivers. 

Few "pure" grey duck (i.e. not hybrids) are now seen in the Miranda area. Like the mallards, 

they feed on aquatic vegetation and seeds. Grass along wetland margins is grazed. Pregnant 

female ducks and ducklings feed on many freshwater or marine invertebrates, such as snails, 

insect larvae and adults and crustaceans. 

Black swan - Cygnus atratus An occasional visitor in small numbers. 

Canada goose - Branta canadensis An occasional visitor in small numbers. 

Paradise shelduck - Tadorna variegata 

A resident in the coastal grassland and wetland areas, this duck is fairly common in areas 

slightly removed from the coast. They nest in areas of farm ponds, banks of rivers and canals 

and wetlands with rushes. Nests are often placed in a hole in a tree or in the ground. 

Brown teal - Anas aucklandica 

This duck is now regarded as endangered. Its stronghold is on Great Barrier Island. 

Occasional birds have been seen at Miranda. 

Australasian shoveler - Anas rhynchotis 

This duck occurs regularly at Miranda, generally in small numbers. Shovelers frequent 

freshwater lakes and other fertile shallow wetlands (including sewage ponds), particularly in 

areas fringed in raupo. They nest in dense rank pastures or areas of sedge, often some way 

from water. Shovelers feed on small aquatic plants, such as duckweed, by dabbling in 

shallow water or in wet mud. They also feed on small invertebrates such as snails and water 

insects. 

New Zealand scaup - Aythya novaeseelandiae 

This duck is an occasional visitor (sometimes in flocks) to estuaries and tidal areas. They 

feed by diving and eating aquatic plants and invertebrates such as freshwater snails. 

Family : RALLIDAE 

Banded rail - Rallus philippensis 

This indigenous rail is secretive in its habits. A few inhabit the mangrove swamps, salt 

marshes and coastal freshwater wetlands. Nests are well hidden in rushes or thick grassland. 

The diet consists chiefly of gastropod snails (Potamopyrgus, Amphibola), crabs, worms, 

spiders and insects; they also feed on seeds and fruits, and on succulent leaves. 

Pukeko - Porphyrio porphyrio 

Pukeko frequent damp pasture, lake and river margins, but are rarely seen on tidal mud flats. 

They are very common in the upper intertidal band adjacent to the stop banks between the 

Waihou and Waitakaruru Rivers. This band was “reclaimed” by mangrove advancement in 


68 

the area. They nest on platforms in tall grass or rush clumps, which generally are standing in 

water. Quite frequently groups of birds combine in nesting activities. Pukeko mainly feed on 

plant material, often stripping seed heads, in pastures and swamps. 

Spotless crake - Porzana tabuensis 

This indigenous rail is widely distributed in Australasia and the Pacific Islands, inhabiting 

raupo swamps and flax and sedge-dominated wetlands. It is a very secretive species and 

appears to be uncommon at Miranda. 

A number of oceanic or coastal birds have been seen in the Miranda coastal area. Some of 

these nest locally and may have important impacts in the Ramsar Site. Other species, that are 

considered rare vagrants, are included at the end of this section. 

Family : PHALACROCORACIDAE 

Black shag - Phalacrocorax carbo 

These shags frequent coastal waters, estuaries, streams, etc. They nest in colonies in large 

trees overhanging the water, but generally feed alone. The diet is mainly small fish (

69 

Little black shag - Phalacrocorax sulcirostris 

This shag is common in coastal waters. It nests in large colonies in trees, such as willows, 

that overhang freshwater. They feed on freshwater crayfish and fish such as bullies, whitebait 

and smelt 

Little shag - Phalacrocorax melanoleucos 

Little shags are found in estuaries, rivers, lakes and in sheltered coastal waters. They nest in 

large colonies in large trees overhanging freshwater or estuaries. They feed on freshwater 

crayfish and small fish (

70 

Family : LARIDAE 

Black-backed gull - Larus dominicanus 

Black-backed gulls are common in estuaries, wet and freshly ploughed pasture and arable 

land, as well as urban parks and rubbish dumps. These gulls nest, in spring, in small to large 

colonies on sandspits, coastal dunes and grassy areas, salt marshes, etc. The diet consists of a 

wide variety of foods, from offal and carrion to algae, fish, molluscs, annelids and 

echinoderms in coastal waters which they often obtain through plunge diving. On land this 

gull feeds on earthworms, insects, lizards, young birds and, in lambing paddocks, they will 

feed on placentas and dead lambs. Black-backed gulls breed on the Miranda-Kaiaua Coast. 

On November 5, 1998 there were seven Black-backed gull nests, containing 2-3 eggs, in the 

grassy savannah area to the east of the stopbank between the Hot Springs pump station and 

the Karito Canal. 

Red-billed gull - Larus novaehollandiae 

This gull is common in coastal as well as inland in wet paddocks and urban areas. Red-billed 

gulls nest in large, dense colonies on shell banks, sandspits, rocky headlands, etc. In summer, 

the diet consists of marine invertebrates and small fish. On land they feed on earthworms and 

insects, particularly in damp pastures. A few birds steal the eggs of other red-billed gulls or 

of White-fronted terns. In autumn and winter they feed on offal, carrion, marine 

invertebrates, molluscs and fish. Red-billed gulls breed on the Thames Coast. 

Black-billed gull - Larus bulleri 

The black-billed gull has breeding colonies in the Firth of Thames. It has previously nested at 

Miranda (from 1968) and in the 1990s has nested near the mouth of the Waihou River 

(Woodley, 2001, pers. comm.). They nest on sandspits, boulder banks and shellbanks in the 

North Island. During the breeding season, they feed on fish and small invertebrates in 

streams and lakes, and on insects and their larvae in wet pastures. During winter they 

frequent estuaries, harbours, lakes and parks of coastal towns, feeding mainly on freshwater 

and marine invertebrates, small fish, etc. (Medway 2000). 

Caspian tern - Sterna caspia 

This tern roosts in small flocks, but usually feeds singly. They nest in loose colonies, on 

sandy beaches, estuarine shell banks and sandspits. Their diet consists mainly of small, 

surface-swimming fish, such as smelt, piper, small flounder, stargazer and yellow-eyed 

mullet. Inland they feed on whitebait, smelt, bullies, trout and small eels, and on worms. 

White-fronted tern - Sterna striata 

This tern is the species most common tern in New Zealand waters. They nest in large 

colonies on shell banks, sandspits, sandy beaches, as well as on rocky islets and cliffs. This 

tern is gregarious and may form joint colonies with red-billed gulls. The diet include small, 

surface-shoaling fish - smelt and pilchards. They also feed on small fish amongst shoals of 

kahawai and kingfish. They may sometimes be seen resting on floating debris, and in ones 

and twos on the floats of mussel farms. 

White-winged black tern - Chlidonias leucopterus A rare vagrant 

Black-fronted tern - Sterna albostriata A rare vagrant 

Fairy tern - Sterna nereis A rare vagrant 

Little tern - Sterna albifrons An irregular visitor 

Arctic tern - Sterna paradisaea A rare, but regular visitor 

Crested tern - Sterna bergii A rare vagrant 


71 

6.8 Terrestrial Species 

A few of the terrestrial birds found at Miranda are listed here - the full list is in Appendix 6.1. 

These species have been highlighted because of their particular association with the Miranda 

Wildlife Sanctuary area: 

Family : ACCIPITRIDAE 

Australasian harrier, Kahu - Circus approximans 

This harrier is common in the coastal area of Miranda-Kaiaua, frequently hawking over the 

pastures, swampland and old shell banks. 

Generally the nest is made in rank grass, bracken fern, areas of rushes and on the ground in 

swamps. This bird feeds on carrion and live prey, such as rabbits, hedgehogs, rats and mice, 

small birds (including ducks), frogs, lizards, fish and large insects (crickets, grasshoppers). 

The carrion includes dead possums and hedgehogs (on roads) and dead sheep (on farms). 

Family : ALCEDINIDAE 

Kingfisher, Sacred Kingfisher, Kotare - Halcyon sancta 

Kingfishers are frequently to be seen in the coastal area - in tidal estuaries, mangrove swamps 

and along stream edges. They also frequent forest edges. Kingfishers nest in hollow 

branches or tree-trunks, in riverbanks and coastal cliffs. On the tidal mud flats, their principal 

food is crabs, particularly the burrowing mud crab, Helice crassa. In freshwater streams, they 

eat tadpoles, crayfish and small fish. In open country and forest edges, they feed on 

earthworms, large insects, such as stick insects, cicadas, wetas, chafers, dragonflies, etc., 

spiders, lizards, mice and small birds. 

Family : ALAUDIDAE 

Skylark - Alauda arvensis 

This introduced bird is frequently seen (and heard) in open country - along the shellbanks and 

in the pastures. They were frequently seen during the 1998 coastal survey between the 

Waitakaruru and Kauaeranga Rivers. The nest is a grass-lined cup in a depression in the 

ground, such as a hoofprint, and is often hidden by clumps of rush or grass. Skylarks feed on 

the seeds and seedlings of low-growing plants, such as grasses and sedges. They also eat 

invertebrates such as spiders, insect larvae and adults (flies, bugs, beetles, and moths). 

Family : HIRUNDINIDAE 

Welcome Swallow - Hirundo tahitica 

The Welcome Swallow is self-established in New Zealand (from Australia), with the first 

report of breeding in 1958. It is now common in the Ramsar Site and throughout open 

country such as lowland farmland with streams and wetlands. The nest is built on rough 

vertical surfaces - on or in houses, sheds, bridges or jetties, etc.. Swallows collect all their 

food whilst on the wing; the diet consists of spiders and insects (flies, beetles, moths, etc). 

Family : MOTACILLIDAE 

New Zealand Pipit, Pihoihoi - Anthus novaeseelandiae 

This is a frequent bird of open spaces - sandy beaches, rough grassland and coastal 

marshland. The pipit has decline in numbers at Miranda in recent years. The nest is a deep 

cup typically concealed in clumps of grass, bracken fern or small bushes. Pipits feed on small 

invertebrates, such as spiders, larvae and adult insects (beetles, moths, bugs, crickets, etc). 

and sandhoppers (Crustacea). They feed, to a small extent, on the seeds of grass and weeds. 


72 

Family : SYLVIIDAE 

Fernbird, Matata - Bowdleria punctata 

Fernbirds are found in low, dense ground vegetation with emergent shrubs in coastal 

wetlands, estuaries, salt marshes and mangrove swamps. They are rarely reported at Miranda 

but are present on other parts of the Ramsar coastal area. The nest consists of a deep cup of 

dry grass, rush and sedges, generally lined with feathers. The main food of fernbirds consists 

of invertebrates - caterpillars, spiders, insect larvae and adults (beetles, moths, flies, etc). 

Family : FRINGILLIDAE 

Goldfinch - Carduelis carduelis 

This introduced finch is common in farmland, orchards and open spaces. Goldfinches make a 

small nest of dry grass, moss, wool and fine twigs, etc.; it is generally placed near the top or 

outside of a tree, such as a conifer, apple or peach tree. Goldfinches feed on a variety of weed 

seeds (thistle, grass, redroot, storksbill, etc). In the Spring particularly, invertebrates such as 

spiders, caterpillars, beetles, bugs, flies, etc., form an important part of the diet. 

Family : STURNIDAE 

Starling - Sturnus vulgaris 

This introduced bird is common in lowland agricultural areas; it is gregarious in autumn and 

winter, forming large flocks. Starling nest in holes in trees, etc. - the nest is a loose cup of dry 

grass, leaves and twigs. The diet of starlings is mixed, with invertebrates, fruit and nectar 

(from flax and pohutukawa) being important. The invertebrates include grass grubs 

(Coleoptera), larvae of porina moths, snails, spiders and worms from pasture or crop stubble. 

Starlings visit mudflats, feeding on worms, etc. Starlings also feed on fruit, both fallen and 

on the tree. 

Myna - Acridotheres tristis 

An introduced bird, common in farmland and open country. The nest is a cup of dry grass, 

leaves and twigs, usually in a hole in a tree or cliff. Mynas are omnivorous, feeding on fruit, 

food scraps, and many invertebrates, such as insect larvae and adults (caterpillars, bugs, 

beetles, etc), spiders and snails. They also eat lizards and birds' eggs and chicks. 

Family : CRACTIDAE 

Australian Magpie - Gymnorhina tibicen 

This introduced bird is common in arable farmland areas, with large trees, such as 

macrocarpa, pine or eucalypt. The nest is generally high up in tall trees; it consists of a 

platform of twigs, lined with small twigs, leaves, dry grass and wool. The nest site is fiercely 

defended from intrusion by other animals and people. Magpies feed principally on 

invertebrates, such as worms, spiders, snails and insect larvae and adults. They also eat grain 

and seeds and occasionally birds' eggs and chicks, small birds, lizards, mice and carrion, 

including dead lambs and sheep. 


73 

Figure 6-4 Wader watchers: a common sight at Miranda and Taramaire from October to April 

(photo K. Woodley). 


74 

Appendix 6.1 The Birds of Miranda and the Firth of Thames 

Common names Local names Scientific names 

NZ dabchick Weweia Poliocephalus rufopectus 

Royal albatross Toroa Diomedea epomophora 

Light-mantled sooty albatross Phoebetria palpebrata 

Cape Pigeon, pintado Petrel Daption capense 

Flesh-footed shearwater Toanui Puffinus carneipes 

Buller’s shearwater Puffinus bulleri 

Fluttering shearwater Pakaha Puffinus gavia 

Northern giant petrel, Nelly Macronectes halli 

Kerguelen petrel Lugensa brevirostris 

Black petrel Taiko Procellaria parkinsoni 

Little blue penguin Korora Eudyptula minor 

Masked booby, blue-faced booby Sula dactylatra 

Australasian gannet Takapu Morus serrator 

Black shag, great cormorant Kawau Phalacrocorax carbo 

Pied shag Karuhiruhi Phalacrocorax varius 

Little black shag Phalacrocorax sulcirostris 

Little pied shag, little shag Kawaupaka Phalacrocorax 

melanoleucos 

Spotted shag Parekareka Stictocarbo punctatus 

Lesser frigatebird Fregata ariel 

White-faced heron, blue heron Ardea novaehollandiae 

White heron Kotuku Egretta alba 

Little egret Egretta garzetta 

Reef heron Matuku moana Egretta sacra 

Cattle egret Bubulcus ibis 

Australasian bittern Matuku Botaurus poiciloptilus 

Glossy ibis Plegadis falcinellus 

Royal spoonbill Kotuku-ngutupapa Platalea regia 

Black swan Cygnus atratus 

Canada goose Branta canadensis 

Paradise shelduck Putangitangi Tadorna variegata 

Mallard Anas platyrhynchos 

Grey duck Parera Anas superciliosa 

Grey teal Tete Anas gracilis 

Brown teal Pateke Anas aucklandica 

Australasian shoveler Kuruwhengi Anas rhynchotis 

NZ scaup Papango Aythya australis 

Australasian harrier Kahu Circus approximans 

Red-legged partridge Alectoris rufa 

Brown quail Synoicus ypsilophorus 

Pheasant, ring-necked pheasant Phasianus colchicus 

California quail Callipepla californica 

Banded rail Moho-pereru Rallus philippensis 

Spotless crake Puweto Porzana tabuensis 

Pukeko Pukeko Porphyrio porphyrio 


75 

S. I. pied oystercatcher Torea Haematopus ostralegus 

Variable oystercatcher Toreapango Haematopus unicolor 

Pied stilt Poaka Himantopus himantopus 

Black stilt Kaki Himantopus novaezelandiae 

NZ dotterel Tuturiwhatu Charadrius obscurus 

Banded dotterel Tuturiwhatu Charadrius bicinctus 

Large sand dotterel Charadrius leschenaultii 

Mongolian dotterel Charadrius mongolus 

Oriental dotterel Charadrius veredus 

Black-fronted dotterel Charadrius melanops 

Ringed plover Charadrius hiaticula 

Wrybill Ngutuparore Anarhynchus frontalis 

Lesser (Pacific) golden plover Pluvialis fulva 

Grey plover Pluvialis squatarola 

Spur-winged plover, masked lapwing Vanellus miles 

Turnstone, ruddy turnstone Arenaria interpres 

Lesser knot, red knot Huahou Calidris canutus 

Great knot Calidris tenuirostris 

Sanderling Calidris alba 

Dunlin Calidris alpina 

Curlew sandpiper Calidris ferruginea 

Sharp-tailed sandpiper Calidris acuminata 

Pectoral sandpiper Calidris melanotos 

Baird’s sandpiper Calidris bairdii 

Red-necked stint Calidris ruficollis 

Western sandpiper Calidris mauri 

Broad-billed sandpiper Limicola falcinellus 

Asiatic dowitcher Limnodromus semipalmatus 

Eastern curlew Numenius madagascariensis 

Whimbrel Numenius phaeopus 

Little whimbrel, little curlew Numenius minutus 

Bar-tailed godwit Kuaka Limosa lapponica 

Black-tailed godwit Limosa limosa 

Hudsonian godwit Limosa haemastica 

Siberian tattler Tringa brevipes 

Wandering tattler Tringa incana 

Common sandpiper Tringa hypoleucos 

Greenshank Tringa nebularia 

Marsh sandpiper Tringa stagnatalis 

Terek sandpiper Tringa terek 

Red-necked phalarope Phalaropus lobatus 

Pomarine skua Stercorarius pomarinus 

Arctic skua Stercorarius parasiticus 

Long-tailed skua Stercorarius longicaudus 

Black-backed gull Karori Larus dominicanus 

Red-billed gull Tarapunga Larus novaehollandiae 

Black-billed gull Larus bulleri 

White-winged black tern Chlidonias leucopterus 


76 

Black-fronted tern Tarapiroe Sterna albostriata 

Caspian tern Taranui Sterna caspia 

White-fronted tern Tara Sterna striata 

NZ fairy tern Sterna nereis 

Little tern Sterna albifrons 

Arctic tern Sterna paradisaea 

Crested tern Sterna bergii 

NZ pigeon Kereru, Kukupa Hemiphaga novaeseelandiae 

Spotted dove Streptopelia chinensis 

Sulphur-crested cockatoo Cacatua galerita 

Eastern rosella Platycercus eximius 

Rainbow lorikeet Trichoglossus haematodus 

Shining cuckoo Pipiwharauroa Chrysococcyx lucidus 

Long-tailed cuckoo Koekoea Eudynamys taitensis 

Kingfisher Kotare Halcyon sancta 

Skylark Alauda arvensis 

Welcome swallow Hirundo tahitica 

Tree martin Hirundo nigricans 

NZ pipit Pihoihoi Anthus novaeseelandiae 

Hedge sparrow, dunnock Prunella modularis 

Song thrush Turdus philomelos 

Blackbird Turdus merula 

Fernbird Matata Bowdleria punctata 

Grey warbler Riroriro Gerygone igata 

Fantail Piwakawaka Rhipidura fuliginosa 

North Island tomtit, pied tit Miromiro Petroica macrocephala 

Silvereye, whiteye Tauhou Zosterops lateralis 

Bellbird Korimako, Makomako Anthornis melanura 

Tui, parson bird Tui Prosthemadera novaeseelandiae 

Yellowhammer Emberiza citrinella 

Chaffinch Fringilla coelebs 

Goldfinch Carduelis carduelis 

Greenfinch Carduelis chloris 

Redpoll Carduelis flammea 

House sparrow Passer domesticus 

Starling Sturnus vulgaris 

Myna Acridotheres tristis 

White-browed woodswallow Artamus superciliosus 

White-backed magpie Gymnorhina tibicen 

Rook Corvus frugilegus 


77 

7 Estuarine Fish, Fisheries and Marine Farming 

by Bill Brownell and Marie Buchler 

With contributions by: commercial fishermen Rex Smith, Ted Howard, Doug Pulford and 

Dick Teklenberg; Mussel farmer Mark Aislabie; NIWA fisheries scientists Larry Paul, 

Malcolm Francis and Peter Smith. 


The vast shallows of the intertidal portion of the Ramsar Site and the adjoining subtidal zone 

are of critical ecological importance to many fish and shellfish species, particularly as a 

feeding ground, and also as spawning and/or nursery areas for some species. 

The upper (southern) part of the Firth of Thames is generally considered by fishermen to 

include all of the water south of a line between Kaiaua on the western shore and Thames in 

the east. This includes all of the waterways and the extensive intertidal area of the Ramsar 

Site. It is estuarine, with surface salinity ranging from close to 0 parts per thousand (ppt) in a 

heavy rain at low tide, to over 30 ppt with a flood tide on a dry summer day (Young & 

Harvey, 1996) There are also extremes of desiccation, flooding, heavy (and shifting) 

sedimentation rates, anoxic mud often as close as five centimetres below the surface (greatly 

limiting the available habitat for most burrowing organisms), high water turbidity levels, slow 

flushing rates (on calm days and neap tides), and heavy wave action during occasional strong 

northerly winds. Midsummer surface water temperatures in the shallows on a calm sunny day 

often reach 27 o C which can be lethal to the juveniles of some species, such as flounder. 

Resident and transitory aquatic species must be able to tolerate these extremes, or evade them 

when they occur. 

There is a diverse and abundant fish fauna in the shallows of the upper Firth. This is mainly 

due to the high productivity of the system and the abundance of prey species such as jellyfish, 

crabs, shellfish, polychaete worms, smelt, anchovy, pilchards, whitebait, yelloweyed mullet, 

glass eel stage of Anguilla spp., speckled (harbour) sole (Peltorphamphus latus), and 

yellowbelly flounder (Rhombosolea leporina). 

Most of these prey species also figure in the diets of one or more of the sea birds and waders 

that come to the upper reaches of the Firth in search of food (especially gulls and terns, 

gannets, herons, shags, and spoonbills). Appendix 6.1 provides a list of the species of fish that 

have been reliably reported from the area. 

A number of other species of vertebrate marine animals are regular visitors to the Firth of 

Thames, sometimes venturing into the southern shallows. These include killer whales 

(Orcinus orca), which appear in the Firth as far south as Thames and Miranda nearly every 

year. Brydes, minke, southern beaked and possibly pilot whales occasionally venture into the 

area, mainly for feeding (T. Howard, personal communication, 2001). 

Two very tropical species of sea turtle, the leatherback (Dermochelys coriacea) and the 

hawksbill (Eretmochelys imbricata) have been reported in the upper Firth (T. Howard, 

personal communication 2001), and green turtles (Chelonia mydas), particularly juveniles, 

have been seen further out in the Firth. Common dolphins are occasionally seen in the 

shallows by fishermen (T. Howard, personal communication 2001). There has been a leopard 

seal temporally in residence around the mouth of the Waitakaruru River in December 2000 

(R. Smith, personal communication 2001). 


78 

Customary fisheries in the Ramsar Site and environs (especially in the Waihou River) remain 

a taonga for Hauraki iwi. The principal target species have historically been eels, inanga, 

smelt, yelloweyed mullet, grey mullet, flounder, snapper, rig, bronze whaler shark, and 

kahawai (Hauraki Maori Trust Board, 1999). Both the abundance of and the accessibility to 

these species and others have been altered by human impact through deforestation (from both 

burning and logging) of the Coromandel, Kaimai and Hunua Ranges, the effects of many 

drainage schemes, mining in the Ohinemuri Catchment and the Thames area, intensive 

agriculture (mainly dairy farming), and commercial fishing (which has only been seriously 

regulated since the late 1970s). Through the practice of Tikanga Maori harvest controls, and 

the relatively low levels of human habitation and fishing technology, most of the natural 

fisheries stocks remained strong until the beginning of the 1940s and the onset of the Second 

World War. 

Commercial fisheries in the Firth of Thames, as elsewhere, escalated during that war and 

expanded steadily (with only minimal controls) until the 1970s. There was some dredging for 

greenshell mussels between the late 1920s and late 1930s). But the dredge fishery for this 

species began in earnest in 1943, reached peak production of 40,910 sacks (21-25 kg/sack) in 

1961, and rapidly petered out to only 384 sacks in 1967 (Reid, 1969). The most productive 

beds in that fishery were between Orere Point and New Brighton (now known as Kaiaua- 

Miranda), some of which were within the present boundary of the Ramsar site. After 37 years 

of “rest” from commercial fishing, the natural mussel resource in the Firth of Thames has 

failed to recover (Morrison et al 2002). Possible causes of this are habitat destruction from 

overfishing, siltation, lack of any established adult populations (to help stimulate juvenile 

settlement) and absence of algae cover to encourage spat settlement. 

Dredging for mussels and scallops is very destructive on marine habitats (Thrush, Hewitt, 

Cummings, & Dayton, 1995), especially on soft substrates like the upper Firth. There are now 

only limited patches of suitable substrate for scallops, oysters and mussels in the area. 

Trawling for fish, once carried out in the Firth (mainly targeting snapper) is also particularly 

harmful to soft bottoms. These two practices, combined with heavy sedimentation, have 

reduced the amount of bottom habitat available to species that either attach to, or burrow into, 

firmer substrates. 

7.2 Recent Biological Phenomena in the Firth of Thames 

The 1990s brought along other environmental changes. These include a number of recognized 

national marine biosecurity concerns (Cranfield, et al., 1998). The carpet mussel or Asian date 

mussel (Musculista senhousia), probably introduced as larvae in ballast water, started 

spreading over moderately stable muddy bottoms in the Hauraki Gulf in the late 1980s 

(Creese, Hooker, De Luca & Wharton, 1997). This is now a dominant species in the Firth of 

Thames benthos. 

Blister worms (or mud worms, Polydora spp.) have become a serious problem, affecting 

scallops, mussels and oysters throughout and beyond the Firth of Thames in recent years. 

These greatly weaken the shellfish, and can lead to significant mortalities (Handley, 1998). 

The worst offender, Polydora haswelli, is now well established in the Firth of Thames even 

though it was not even known in New Zealand (Mahurangi Harbour) until 1996 (Read and 

Handley, 2004). 

Since 1997, the parchment worm (Chaetopterus sp), a polychaete tubeworm, also probably 

introduced, has taken over vast areas of benthic habitat in the Gulf. It was first noticed in the 

upper Firth in 2000, growing on mussel culture lines at Waimangu Point and on slightly 


79 

firmer patches of bottom near the Ramsar Site. In July and August 2001 it was heavily fouling 

the mussel droppers and disrupting the harvesting process (M. Aislabie, personal 

communication, 2001). In 2003 and 2004 parchment worms were much less abundant in the 

Firth. In late 2004 they were not a problem anywhere in the Hauraki Gulf (S. Hooker, NIWA, 

personal communication 2004). 

“Black gill disease” played a major role in the die-offs of scallops in the Firth (and 

throughout the Gulf) in 1997-98. A NIWA study (Diggles, 1999) concluded that this poorly 

understood disease was caused by a prokaryote-like organism, and was a result of 

“environmental changes”. The physical manifestation of the disease is “severe deterioration 

of condition” and necrosis of the gills and mantle. 

The Hauraki Gulf contains several species of scavenging flatworms (Platyhelminthes), at least 

one of which has predatory tendencies (S. Handley, NIWA, personal communication 2000). 

One unidentified species was abundant in the Firth in 1998, and may have contributed to 

heavy mortalities of scallops, mussels and oysters that year. It appears that the shellfish were 

already in a weakened condition from one or more of the above factors. (M. Aislabie, 

personal communication, 2000). 

The recent increase in marine farming structures (mainly for mussels and oysters) in the Firth 

of Thames, and the major push by industry for exponential growth of aquaculture in the years 

to come, has led to the creation of significant new habitat, particularly in the form of mussel 

buoys, backbone lines and dropper lines. This is creating a steady increase in the availability 

of suitable substrate for sessile invertebrates (such as hydroids, ascidians and fouling mussels) 

which arrive in their mobile larval forms and mature in situ to produce greatly increased 

quantities of larvae that, in turn, have even greater opportunities for finding suitable substrates 

for attachment. 

Widespread mortalities of pilchards (Sardinops pilchardus) occurred throughout the Firth of 

Thames from June to August 1995 (Smith, et al., 1996). While there have been several reports 

of pilchard die-offs from around New Zealand during the twentieth century, the 1995 event 

was perhaps the worst, especially in the Firth: 180-200 tonnes of dead pilchards were 

estimated to have washed up on the beaches of the Thames Coast. Based on subsequent 

Australian research, the direct cause of the 1995 event was most likely a virus (P. Smith 

NIWA, personal communication 2001), probably exacerbated by other environmental factors. 

Dinoflagellates (motile microscopic algae) in the plankton, causing the production of toxins in 

shellfish, produced unusually large blooms in the Firth in 1994, shutting down all shellfish 

harvesting there and elsewhere for several months. The blooms of 2000-2001, mainly on the 

West Coast of the North Island, did not reach the Hauraki Gulf, but it remains a potential 

threat. 

Another biosecurity issue is the flora and fauna brought in on wet, poorly picked nets by 

fishers from further afield such as the Kaipara Harbour, Whangarei or the Bay of Plenty, thus 

risking introductions of non-resident species and/or pathogens (R. Smith, personal 

communication, 2001). 

The introduced Pacific oyster (Crassostrea gigas) replaced the native rock oyster (C. 

glomerata) in the 1970s as the dominant species throughout the region including the Ramsar 

Site. Oysters are particularly abundant in the lower parts of the rivers and canals, and around 

the margins of the shellbanks. 


80 

High levels of nutrients from offshore upwelling, runoff from the surrounding catchment, and 

the decomposition of vast amounts of vegetative matter produced in the coastal zone, 

combined with relatively high water temperatures in the Firth of Thames, precipitate the 

periodic appearance of dense blooms of phytoplankton. This is the cornerstone of the 

enormous biomass production of the Firth. This phenomenon has been a focus of 

oceanographic research by NIWA, particularly over the past ten years, and the work is 

continuing, especially driven by the growing economic interest in aquaculture. 

The availability of nutrients is now known to be extremely variable as a result of the 

oscillation between El Ni o and La Ni a cycles (Zeldis, Sharples, Uddstrom & Pickmere, 

1998; Zeldis, Gall, Uddstrom & Grieg, 2000), considerably affecting productivity. The 

significant variations in mean monthly surface water temperatures in the Firth (closely tied to 

the El Ni o cycle) can greatly affect species composition, abundance and growth rates of 

organisms, and their susceptibility to pathogens. 

Besides the natural changes in the physical environment and the history of human-induced 

environmental impacts on the Firth of Thames (particularly from the catchment and from 

marine biosecurity breaches), the many contemporary human influences around Auckland and 

the Hauraki Gulf threaten the natural balance of this fragile estuarine ecosystem. These 

include: extensive stormwater runoff, erosion from roading and subdivision construction, 

inadequate municipal sewage management, dredging of ports and channels (including marine 

disposal of the spoils), heavy shipping activity and sand mining. 

7.3 Marine Farming in the Firth of Thames 

There is no marine farming in the upper Firth of Thames because of its extreme shallowness, 

muddiness and lack of accessibility. However, mussel farming occurs just north of Thames at 

Wilson’s Bay and north of Kaiaua at Matingarahi. Both these areas, and others between and 

beyond, have recently been targeted by the mussel farming industry as the next major national 

area to be developed. This is logical, as these waters are among the most productive in the 

New Zealand coastal marine environment, and they are also very sheltered. 

The Firth has been a major producer of shellfish for at least 12 000 years, as witnessed by the 

massive Miranda shellbanks. Cockles are still abundant, even with heavy sedimentation that 

sometimes suffocates them. Pacific oysters grow wherever there is something to attach to, 

most often on the shells of their dead predecessors buried in the mud, particularly in and 

around the mouths of streams and rivers. Dredge fisheries for mussels and scallops have 

come and gone, and the shellfish keep coming back. 

Larval settlement of significant numbers of mussels and scallops happens periodically (M. 

Aislabie, personal communication, 2000). This has been demonstrated by collector bags and 

ropes placed by marine farmers at numerous locations around the Firth ever since the first 

large-scale attempts in 1987-89 by Bartrom (1989). Despite these positive indications for 

filter-feeding shellfish, we have yet to establish the carrying capacity of the phytoplankton 

production of the system to determine the biomass of shellfish it can sustain in the years of 

highest and lowest nutrient delivery from the three main sources of enrichment (NIWA, 

2002). A recently completed modelling study (Broekhuizen et.al. 2003) concludes that an 

additional 4,300 hectares of mussel farming in the Firth would not significantly deplete the 

natural stocks of phytoplankton. As at December, 2004 this had not been adequately verified. 

As of November 2002 there were applications pending for a total of 6000 additional hectares 

of water for mussel spat collection (and eventually farming) centred at the Matingarahi site 


81 

(between Kaiaua and Orere Point). Such magnitude of marine development would have 

implications in all areas of resource use allocation in the Hauraki Gulf involving recreation, 

agriculture, fisheries, coastal subdivision, conservation, natural history education and tourism. 

Marine farming is here to stay, decided in early 2001 during the extensive aquaculture 

development deliberations in relation to the proposed Waikato Regional Coastal Plan. As a 

precautionary approach, EW decided to provide for an additional staged development of 1000 

hectares of marine farming at Wilson’s Bay, subject to the results of intensive monitoring of 

farming activities (starting with an initial development of 250 hectares). 

It is yet to be established what sort of scale would be sustainable. More research is needed on 

the demands placed on this estuarine ecosystem by its resident fauna, migratory and seasonal 

birds and fishes, and the present harvesting of wild stocks by humans before large areas of 

water are committed to monocultures of marine farming. 

7.4 Fishing Activity in the Firth of Thames 

Commercial fishing in the Firth of Thames declined over the past decade, through the scarcity 

of snapper for several years during the period of the late 1970s through to the 1990s, and the 

resulting restrictions on commercial activity, including a total ban on Danish seining. There 

is still a robust local commercial fishery for rig and flounder, and some continued snapper 

effort, involving small, local (usually trailer-launched) boats. 

The muddy environment, shallow tidal water, and limited access, keeps the number of 

recreational fishers small. However, increased abundance of snapper “keepers” in the area 

over the past three years led to greater recreational fishing, especially between Thames and 

the Waihou River mouth, and offshore between Miranda and Kaiaua. But the greatest 

recreational effort is in the “lower” (outer) Firth, particularly around the mussel farms on both 

coasts. 

Currently, there are 23 locally based small boats (of lengths less than 9 m) operated by full- to 

half-time commercial fishermen: twelve located in Thames, two at Waihou River (Turua), 

two at the Piako River (Pipiroa), six at Waitakaruru, and one at Kaiaua (see map, Figure 1.1). 

About six of these focus on snapper, one on eels, and the rest on flounders (principally 

yellowbelly). Many also fish for rig during the short spring season. Depending on mesh sizes 

and depth of the nets employed, the location fished, and the time of year, other commercial 

species may be landed as incidental catch. These include kahawai (Arripis trutta), trevally 

(Pseudocaranx dentex), kingfish (Seriola lalandi), jack mackerel (Trachurus 

novaezelandiae), John dory (Zeus faber), grey mullet (Mugil cephalus) and occasionally rays. 

Commercial fishermen with trailer-launched boats based in other locations (mainly in the 

Auckland Region) frequently use the five landing points mentioned above for fishing the 

upper Firth (and down the Thames and Matingarahi coasts), especially during the peak 

spring-early summer flounder season. Outside of these recognised landing points there are 

few locations on the entire Ramsar coast where boats can be launched, moored, or wharfed. 

The old New Brighton limeworks wharf (beside the current Miranda Stream bridge) has long 

been silted in and abandoned. The Wharekawa Quarry just north of Kaiaua currently shelters 

one fully operational mussel barge and has a launch ramp for a private boating club. There 

are occasional launchings at various locations in the Kauaeranga, Waihou and Piako Rivers, 

mainly from private land. 


82 

7.4.1 Eels 

The thick, soft mud of the southern Firth of Thames, and the vast marshlands and tidal creeks 

of the Hauraki Plains provide ideal habitat and food supply for eel. The major catch is the 

shortfinned eel (Anguilla australis). The longfinned eel (A. dieffenbachia) may occur further 

inland, though small numbers were recorded in the estuarine lower reaches of the Miranda 

Stream in 2002 (Sukeforth, 2002). 

According to veteran eel fisherman Dick Teklenburg of Te Kauwhata, eels were historically 

abundant throughout the extensive marshlands of the Hauraki Plains before the stopbanks 

were constructed along the rivers, drainage canals and coast of the Firth. (The stopbanks 

reduced the area of the original marshlands by over 80%). Eels have been found in great 

concentrations in the peat bogs more than 20 kilometres from the coast, having come in on a 

flood tide, and often remaining in hibernation in the peat until the next flood tide arrives. 

Shortfinned eels thrive in the highly productive estuarine environment of the Ramsar site and 

its environs. They devour great quantities of the small and abundant harbour or speckled sole 

(Peltorhamphus latus), crabs (the three species of mud crabs found in the area, Hemigrapsus 

crenulatus, Macropthalmus hirtipes and Helice crassa), juvenile Rhombosolea spp. flounders, 

and small schooling “baitfish” species (R. Smith, personal communication, 2001). 

Fishers consider that the shortfinned eels of the Firth of Thames estuary grow particularly 

fast, and to be of exceptional quality, due to the abundance and diversity of food species and 

the quality of the water. One major pollutant in the eels’ environment is agricultural runoff. 

This may be largely positive, contributing nutrients to the ecosystem. However, little is 

known about the effects of agricultural chemicals used in the catchment, especially pesticides, 

fungicides, growth hormones, antibiotics and herbicides. It is also known that heavy metals 

such as zinc, and other pollutants leaching from coastal and inland rubbish dumps and road 

runoff have deleterious effects on marine organisms at specified concentrations. 

However, Environment Waikato did some analysis for a suite of metals at five sites in the 

Firth of Thames (including one at Miranda) and found no levels of concern in relation to 

ANZECC recommendations (M. Felsing, personal communication 2004). Also, there are 

various studies available on runoff composition and environmental impacts at specific sites 

that have been carried out by such entities as the Auckland Regional Council, Tonkin and 

Taylor and NIWA. 

Eels living in and around the Ramsar site may prefer the present muddier habitat in open 

water which has occurred through the increase in sedimentation throughout the past century. 

But less marshland habitat now exists because of the vast reclamation of the Hauraki Plains. 

Juveniles appear to be abundant. The question is whether their concentration into the 

restricted waterways of today leads to more predation by various species of shags, juvenile 

sharks, snapper and kahawai than in earlier times. 

Eel fishing has been practiced since the earliest human habitations of these shores, probably 

since the mid 15th century. Principal fishing methods were hand lining, netting, trapping 

(hinaki), weirs, hand capture from mud holes and spearing (usually with torches at night). 

Eels were the most valuable fishery to the local people of the Waihou River until recent times, 

and they were regularly used for trading (Hauraki Maori Trust Board, 1999). 

Commercial eeling began in the early 1960s. Small mesh nets were set, mainly along the 

southern margin of the Firth on the vast mudflats between the mouth of the Waihou and the 

Indian Floodgate north of Waitakaruru. These nets must be used judiciously, as they can trap 


83 

large quantities of unwanted harbour sole, yelloweyed mullet, juvenile grey mullet, 

jellyfishes, cockle shells and even pilchards if set in the wrong spot, or at the wrong time of 

year (or tide). The nets are pulled as soon as they have fish in them, any bycatch is released 

immediately, and only eels that are well over the minimum legal size are kept. Larger eels 

have greater market value per kilo. 

Fyke nets were employed by some fishers from the mid 1960s, especially in the Waihou and 

Piako Rivers, and are still used there fairly regularly. The only regular commercial eel catches 

today are landed by Ian Dunlop from autumn through spring. He is the only fisher currently 

licensed to fish for eels with set nets in the southern Firth. (Note: the QMS defines 

shortfinned eels as a freshwater species, even though they are commercially caught in salt 

water, and spawn in tropical ocean waters.) Eels are not taken when they set off on their 

spawning migrations. This fishery appears to be sustainable at current levels of exploitation. 

Mature females swim out of the Firth of Thames in autumn. Elvers (“glass eels”) return to 

the Firth of Thames estuary in spring. It would be difficult to quantify the elvers coming into 

the system each year, as they are seldom seen in the very muddy water, but recruitment is 

considered by local fishers (T. Howard, R. Smith, R. Tecklenberg, personal communications 

2001) to be consistently strong. 

When temperatures drop below normal in winter, or if they rise markedly during low tides in 

the middle of a sunny summer day, eels hibernate/aestivate deep down in the mud. They 

readily burrow into black (anoxic) mud. In heavy rain they may become active when water 

temperatures return to normal, salinities are lowered and more food organisms are present. 

7.4.2 Flounder 

Two species of flounder, the yellowbelly (Rhombosolea leporina) and the dab (R. plebeia) 

form the backbone of a small-scale fishery in the upper Firth of Thames. It is estimated that 

total commercial flounder landings at Thames, Waihou, Piako, Waitakaruru and Kaiaua 

average around 150 tonnes per annum from 23 boats. Approximately 40% of this catch comes 

from the Thames Coast north of the Ramsar Site. There is no available estimate of how much 

more is taken from the waters of the Ramsar site by non-local commercial and recreational 

fishers. 

The early commercial flounder fishery started in the 1940s and was based in Thames. In the 

early 1960s Peter Ashby started the fishery on the Kaiaua-Miranda coast. Flounder came 

under quota in the mid 1980s. The current flounder quota for Area 1, which includes the area 

from East Cape to Kawhia in the west, is 1100 tons. This fishery, along with the rig fishery, 

are two of the few left in which most of the quota is in the hands of small-scale fishers. The 

lease price is reasonable – about 30 cents per kilo. Effort is dispersed throughout the vast 

Area 1, and the annual catch usually falls 300 or more tonnes short of the quota. 

Flounder fishers commonly work with “strings” of 70-100 metre nets joined together at 

anchor points to give a total length of 700-1000 metres. The nets are usually only 50-70 cm 

deep, as the fish do not venture far off the bottom. Mesh size ranges from 115 to 137 mm 

(stretch). A typical “dinghy” fisherman will fish 800 metres of net on the incoming or 

outgoing tide and catch up to 240 kg/day, with an average catch of 70-100 kg/day over 110- 

140 fishing days/year. The best catches tend to be made near freshwater outfalls around the 

coastline. 

The best floundering is from spring to early summer (September to January) when the 

predominant species is the slightly larger yellowbelly (minimum size: 25 cm), and the 


84 

average monthly commercial catch/boat is around 1,500 kg. Fishing can often be thwarted by 

“netloads” of jellyfish (up to 5 species and often in great abundance) that come into the area 

most years for about six weeks between late August and early October. By late January the 

fishing usually starts to drop off, mainly due to high water temperatures that cause the fish to 

move out into deeper water. Lowest catches are from May to August, and are predominantly 

dabs (minimum size: 23 cm). The 1995-96 season yielded a total local catch of less than half 

of the yearly average for the past 20 years, but otherwise the yearly catch per effort has been 

steady. 

Both flounder species mature early, and the bulk of the fish caught appear to be two-year 

olds. Size-wise, the biggest “sockers” that is, greater than 400 g for yellowbelly and greater 

than 350 g for dab) tend to be three-year (occasionally four-year) olds. The biggest 

yellowbellies may reach 1200 g, although these are now extremely rare. Today it is 

uncommon to catch fish weighing over 800 g (Rex Smith, personal communication, 2001). 

Both species feed mainly in the intertidal area when the tide is in, primarily on mudcrabs (the 

same three common species that the eels take) and the siphons of bivalves. 

In both species, females grow faster than males: at two years yellowbelly females average 29 

cm, and the males 24 cm, while dabs of the same age average 23 cm for females and only 11 

for males (Colman, 1974b). Males of both species reach sexual maturity well before attaining 

the minimum size for capture, while 95% of dabs and 15% of yellowbelly females are mature 

by the time they reach 23 and 25.4 cm, respectively (Colman, 1972). The only migrations 

these species make are for spawning (June to November for dabs and September to November 

for yellowbellies), a relatively short distance away in the middle of the Firth between Ponui 

and Waiheke in the west and Tapu on the Coromandel side (Colman, 1973). 

Seine netting carried out in November 2001 and April 2002 in the lower reaches of the 

Miranda Stream by EcoQuest Education Foundation showed juvenile yellowbelly flounders 

to be the most abundant of three species of flatfish caught (yellowbelly and sand flounders, 

and speckled sole), and far more abundant in November. In November 2001, 400 yellowbelly 

comprised 42% of the total fish catch, most between 20-49 mm (range 20 – 106 mm) in 

length. Most were caught where the stream channel cuts through the tidal flats near the 

stream mouth. In contrast, only 31 yellowbelly flounder were caught in April seining, 

predominantly in the size range 60 – 69 mm (range 25 – 184mm). (Crowley, 2001; Deimezis, 

2001; Horigan, 2002; Ledwin, 2002; Model, 2002.) 

7.4.3 Snapper 

Snapper (Pagrus auratus) fishing in the Firth of Thames has been a big industry in the recent 

past, though subject to great fluctuations in export prices, size of the resource and the fishing 

gear technology. In the years of big harvests by Danish seiners and longliners a lot of money 

was made by Coromandel and Thames-based fishers and packing sheds. 

After some disastrous years of overfishing by both commercial and recreational fishers 

(especially in the late 1970s to the mid-1980s, and the mid 1990s), consensus among local 

fishermen is that there have been more adult fish in the area over the past three years. The 

Ministry of Fisheries and the Snapper Working Group, in conjunction with on-going Hauraki 

Gulf trawl surveys and a NIWA tagging programme, have been studying snapper recruitment, 

growth and survival for many years, especially since 1981. Results are still inconclusive. 

Very little sampling has been done in the Firth of Thames itself, but it is known that 

recruitment throughout northern New Zealand is highly cyclic. 


85 

Only four or five of the small boats in the upper Firth fish for snapper now. Most of the quota 

is owned by big companies, and the quota lease price of over $4/kg is often only slightly 

below the price paid for landed fish. The bigger boats tend to fish further out in the Firth and 

in the Gulf beyond. 

It is the recreational fishers that are currently benefiting most from the snapper resource in the 

upper Firth. Most of the “weekenders” who know where to go, manage to catch their limit 

easily around the shellbanks and shoals, especially around the mouths of the Waihou and the 

Kauaeranga, and along the coasts northward from Thames and Kaiaua. The mussel farms 

several kilometres north of Kaiaua off Waimangu Point are favourite spots for recreational 

fishers, as the snapper are attracted to the mussel lines for food and shelter. 

In summer, juvenile snapper (probably mainly 2-year olds) move into the Firth in large 

schools to feed. One of their main targets is freshly seeded (30-50 mm) greenshell mussels 

(Perna canaliculus) on marine farms opposite Wilson’s Bay in the east, and off Waimangu 

Point in the west. Past fisheries research indicated that the upper Firth (south of Orere Point) 

was not a nursery ground for snapper (L. Paul, personal communication, 2000), but kahawai 

caught at Thames have had guts full of 35 mm snapper (D. Pulford, personal communication, 

2001). 

Snapper caught in the upper Firth usually don’t have such vibrant colouring as those caught in 

less muddy areas, and therefore don’t fetch such a high price in export markets as those from 

clearer water. They are often called “pipi snapper” because they feed heavily on bivalve 

shellfish in this area. They tend to be in excellent condition. In summer these fish have a 

short shelf life (unless gutted right away) due to the rapidly fermenting food in their 

stomachs. 

7.4.4 Kahawai 

Recreational catches of Kahawai near the coasts of northeastern New Zealand (including the 

Firth of Thames) have declined since the recreational catch sampling programme began in 

2000 (Ministry of Fisheries 2004). Mature adults rarely penetrate very far into the Firth, and 

the population there is mainly 2-3 year olds (B. Hartill, NIWA, personal communication 

2004). 

Surface schools of kahawai may be important in making small pelagic fishes available to 

feeding seabirds. In terms of the Fisheries Act, the interdependence of stocks may be an 

important determinant in setting a target level above that which will produce MSY for prey 

species such as kahawai to allow for predation and ecosystem functioning (Ministry of 

Fisheries 2004). 

Kahawai feed mainly on fishes but also on pelagic crustaceans, especially krill (Nyctiphanes 

australis), while individuals smaller than 100 mm eat mainly copepods (Ministry of Fisheries 

2004). Although kahawai are principally pelagic feeders, they will also take food from the 

seabed. They spawn on the seabed (60–100 m deep) in open water. 

Kahawai entered the QMS in October 2004. The annual quotas set for Area 1 (Cape Reinga to 

East Cape) are: Customary 550 t, Recreational 1865 t, and Commercial 1195 t. The 2002-03 

commercial catch was 933 t, none of it from the Firth of Thames. 


86 

7.4.5 Pilchard (Sardinops neopilchardus), Yelloweyed mullet (Aldrichetta 

forsteri), Ahuru (Auchenoceros punctatus), Grey mullet (Mugil cephalus) 

These four species of small schooling fishes have been variously targeted by commercial, 

recreational and customary fishers in the area for at least a century, and as incidental catch 

(often along with harbour sole) in the small mesh eel nets. They are mostly used for local 

consumption, pickled, smoked (kippers), or fried whole. They are marketed further afield as 

bait for linefishing (especially pilchards and yelloweyed mullet). Today these species are 

most commonly caught in recreational beach seines. Occasional commercial efforts may 

yield up to 2-300 kg per set for yelloweyed mullet, especially in the Waihou, (usually 

targeting fish at the upper end of the size scale that have greater market value). 

Larger grey mullet (30-60 cm) are not as commonly caught in the upper Firth as they are in 

many less turbid estuaries, but are taken with 90 mm stretch mesh nets occasionally and 

smoked for sale in fish shops. Pilchards continue to be abundant in the area and are 

particularly popular as a baitfish, both with recreational fishers and longliners. It appears that 

ahuru stocks have diminished since the 1960s, possibly due to their preference for cooler 

waters than has been the norm in the Firth in recent years (L. Paul, personal communication 

2001). 

Pilchard (S. neopilchardus) entered the QMS in October 2002, with Area 1 quotas set at: 

Customary 10 t, Recreational 20 t, and Commercial 2000 t (Ministry of Fisheries 2004). 

7.4.6 Sharks 

Several species of shark come into the upper Firth at various times of the year to feed or give 

birth. Female hammerheads (Sphyrna zygaena), bronze whalers (Carcharhinus brachyurus) 

and school sharks (Galeorhinus galeus) come in spring to give birth to their young, who use 

the shallows as a nursery before heading out for a life in the more open coastal waters. The 

big brood females of these species have limited value in today’s market, except for the fins of 

the school sharks, and wreak havoc with the nets of fishers. T. Howard (personal 

communication, 2001) reports sighting a white pointer (Carcharodon carcharias) in 1.5 m of 

water off Miranda in 1972. Another was killed by a fisherman in the lower Firth east of 

Waiheke Island in 2004. 

Rig, or lemonfish (Mustelus lenticulatus) is the only shark species in the area that is a regular 

target of commercial fishers. The main food items that constitute their diet in the upper Firth 

are pilchard (Sardinops pilchardus), crabs, squid, jellyfish and sprats. Rig can bring $6/kg or 

more (mainly for export to Australia), and many fishers own their own small amount of quota. 

The fishery lasts just from mid-September to early November, but can be profitable for smallscale 

fishers. 

The nets used for rig are 125 mm stretch mesh, 15-20 meshes deep (usually set within a metre 

or so off the bottom). The majority of the fishers in the area are involved in this small fishery 

for about six weeks a year. 

7.4.7 Whitebait 

Inanga (Galaxias spp.) and smelt (Retropinna retropinna) make up the whitebait fishery, in 

the Waihou and to a lesser extent the Piako. They have been important as a local food source 

since the early days of settlement. Adults migrate downstream to spawn in the lower 

(brackish) reaches of the river systems. Juvenile whitebait are traditionally caught with dip 

nets and scrim nets as they migrate back into the streams after about a six months nursery 


87 

stage in the sea. These species are also components of the diets of some sea birds frequenting 

the area, such as terns and shags. 

7.5 Stream fish surveys 

Fish in the lower catchment of the Miranda Stream have been periodically monitored since 

November 2001 by undergraduate students of EcoQuest Education Foundation as part of their 

Directed Research Projects. Most interesting was the utilisation of the lower reaches of the 

stream by post-larval yellowbelly flounder in early summer. [See section 6.4.2]. These 

studies are ongoing and part of EcoQuest’s aim to understand changes in the species 

composition and abundance, and habitat utilisation by fish at different times of the year and 

the tidal cycle, as well as in different parts of the catchment. 

Profiles of the Miranda Stream have been taken at sites extending 700m upstream from the 

mouth (Beckley 2002, Glatt 2002). They found differences in salinity, substrate and 

vegetation throughout this lower part of the catchment, with seawater incursion being 

recorded throughout the sampling area to 700 m upstream from the mouth. These differences 

affected the distribution and abundance of benthic organisms in the bottom substrate. The 

Polychaete worm Nicon was found at all sites. The Tunneling Mud Crab, Helice crassa, was 

found up to 500m from the mouth. The freshwater Gastropod Potamopyrgus antipodarum 

was found at sites from the upper stream to near the East Coast Road bridge (100 m from the 

mouth). Other studies by Adams (2002) and Rivard (2002) looked at the distribution of fish 

in this same area. 


Adams, D. (2002) A comparison of three surveys of fish composition, distribution and 

abundance in the lower catchment of the Miranda Stream EcoQuest Education Foundation, 


Beckley, J. (2002) Longitudinal variations in available instream habitat in Miranda Stream, 

Spring 2002, Firth of Thames, New Zealand. EcoQuest Education Foundation, New Zealand. 

Unpublished. 

Glatt, S. (2002) Longitudinal variation in the composition of benthic fauna communities in 

the Miranda Stream, Spring 2002, Firth of Thames, New Zealand. EcoQuest Education 

Foundation, New Zealand. Unpublished. 

Rivard, B. (2002) A survey of eel community composition in Miranda Stream, Kaiaua, New 

Zealand : In comparison with November 2001 and April 2002. EcoQuest Education 

Foundation, New Zealand. Unpublished. 

7.6 Fisheries Research 

MAF carried out considerable research between 1960 and 1980 in the Hauraki Gulf, 

periodically sampling stations in the upper Firth. The “Ikatere” carried out trawl surveys at 

three locations in the area (though two of them were slightly north of the Ramsar Site) in the 

1960s, recording data on 26 species (with some follow-up work in the 1970s). The 

“Kaharoa” did similar work from the mid 1980s onward, with a focus on snapper. The earlier 

work has recently been revisited by NIWA, but the data are insufficient for drawing any 

conclusions about fish stocks in the upper Firth (M. Morrison, NIWA, personal 

communication 2004). 


88 

7.7 Conclusions 

It has been suggested that past fishery research records should be reviewed in depth to see if 

some useful baseline data will materialize regarding the fisheries ecology of the Ramsar 

marine environment. In the spirit of the ecosystem approach to fisheries research that has 

been mandated by the Fisheries Act (1996) and the National Biodiversity Strategy (2000), and 

the integrated approaches to marine resource management that are set down in the Hauraki 

Gulf Marine Park Act (2000), an integrated research programme (including the whole Firth of 

Thames marine, estuarine and coastal environment) should be encouraged. 


89 

Appendix 7.1 Fishes of the Southern (“Upper”) Firth of Thames 

Family Latin Name Common Name(s) 

CARTILAGINOUS FISHES 

Triakidae Galeorhinus galeus School shark 

Mustelus lenticulatus Rig, spotted dogfish 

Carcharhinidae Carcharhinus brachyurus Bronze whaler 

Sphyrinidae Sphyrna zygaena Hammerhead shark 

Dasyatidae Dasyatis brevicaudatus Short tailed stingray 

Dasyatis thetidis Long tailed stingray 

Myliobatidae Myliobatis tenuicaudatus Eagle ray 

BONY FISHES 

Anguillidae Anguilla australis Shortfinned eel 

Anguilla dieffenbachi Longfinned eel 

Clupeidae Sardinops neopilchardus Pilchard 

Engraulidae Engraulis australis Anchovy 

Retropinnidae Retropinna retropinna Smelt 

Galaxiidae Galaxias maculatus 

Galaxias spp. 

Whitebait 

Moridae Auchenoceros punctatus Ahuru 

Hemiramphidae Hyporhamphus ihi Piper, Halfbeak, Garfish 


90 

Zeidae Zeus faber John dory 

Triglidae Chelidonichthys kumu Red gurnard 

Carangidae Seriola lalandi Kingfish, Yellowtail 

Pseudocaranx dentex Trevally 

Trachurus novaezelandiae Jack mackerel 

Arripidae Arripis trutta Kahawai, austral. salmon 

Sparidae Pagrus auratus Snapper 

Kyphosidae Girella tricuspidata Parore, blackfish 

Mugilidae Mugil cephalus Grey mullet 

Aldrichetta forsteri Yelloweyed mullet 

Pinguipedidae Cheimarrichthys fosteri Torrent fish 

Tripterygiidae Forsterygion sp. Estuarine triplefin 

Eleotrididae Grahamichthys radiata Graham’s gudgeon 

Gobiomorphus cotidianus Common bully 

Gobiidae Favonigobius lateralis Goby 

Favonigobius exquisitus Exquisite goby 

Pleuronectidae Peltorhamphus latus Speckled sole 

Rhombosolea leporina Yellowbelly flounder 

Rhombosolea plebeia Dab, Sand flounder 

Tetraodontidae Contusus richei Pufferfish, globefish 


91 

8 Benthic Ecology 

Part 1 - A preliminary survey of the intertidal bivalves and 

other benthic fauna in the Firth of Thames Ramsar Site. 

by Nigel Keeley 


Despite being an internationally recognised Ramsar site and an important over-wintering site 

for up to 30,000 actively feeding migratory birds each year (see Chapter 6), the upper Firth of 

Thames and its extensive benthic communities have been poorly studied (Morrison, et. al. 

2002). It is well known that shallow, muddy, highly productive estuaries such as the Firth of 

Thames are important sources of food not only for wader birds, but also for a diversity of 

resident, migratory and juvenile fishes. Competition for these invertebrate food items among 

the various members of the two main groups of higher-level consumers can be intense, and 

often has a high impact on the population densities of both predator and prey. 

This lack of research is due in part to the many physical difficulties that are encountered when 

working in this challenging environment. The vast intertidal mudflats that comprise the upper 

Firth are soft, sticky and virtually inaccessible on foot, and boat access is greatly restricted by 

depth. To overcome these problems a special corer was designed that could be operated from 

a small boat in shallow water. Consequently, this study constitutes the first broad scale look 

at the distribution and abundances of large (>2 mm) macrobenthos in the Firth of Thames 

(FoT) Ramsar Site. 

The primary objective of this study was to provide an insight into the dominant invertebrate 

communities that are present, and to serve as a foundation for making informed 

recommendations regarding the directions of future work (e.g. identifying significant habitats 

and species for ongoing monitoring, and to provide a cursory look at the impacts of wader 

bird feeding and intensity). Additionally, the study was intended to create the beginnings of a 

baseline for measuring effects of acute environmental perturbations (e.g. storm induced 

sedimentation events). To achieve these objectives a total of 30 sites were sampled within the 

Ramsar site at three tidal elevations, yielding a total of 85 shallow core samples (Figure 8-1). 

8.2 Methodology 

8.2.1 Site Selection 

The study area spanned the intertidal region of the lower Firth of Thames, from as far north as 

Kaiaua on the western side and Tararu on the eastern side. Within this area, ten sites were 

chosen around the foreshore according to the following considerations: maintaining an even 

spatial distribution, proximity to the major rivers (Waihou, Piako and Waitakaruru), 

proximity to known wader bird feeding areas, and proximity to relocatable landmarks (from a 

boat). Given the typically featureless nature of much of the coastline, and for the sake of ease 

of repeatability, it was often the latter that dictated the position for the start point of the 

transect. 

Each transect was a theoretical line that ran perpendicular to the shore that was sampled at 

three approximate tidal elevations: just below mean high water (MHW), mid tide, and mean 

low water spring (MLWS). The positions of the sites along the transects were determined 

from the water depth beneath the boat at or near high tide (±1:00 h) using an acoustic depth 


92 

sounder, where depth at MHW ≈ 0.6-0.8 m, mid ≈ 1.2-1.5 m and MLWS ≈ 2.3-2.5 m. All 

sampling was carried out at approximately midway through the cycle of spring and neap tides. 

Once established, the depth (± 0.1 m) and time was noted and co-ordinates were recorded 

from a hand held GPS (±10 m). At sites “a”, a photograph of the shoreline and additional 

notes were taken to help with relocation for follow up work (Figure 8-1). 

Whakatiwai Stream 

Key 

Wharekawa 

Wkakatiwai 

Kaiaua 

Depth contours in 

meters. 

Matingarahi Pt 

Waihihi Bay 

Miranda 

10 

5 

2 

N TN 1999 

1 

10 

2 

Waitakaruru 

FIRTH OF THAMES 

5 

Boat channel 

10 

15’ o 25’ 175 20’ 

30’ 35’ 


2 

5 

1 

Pipiroa 

Waihou River 

Piako River 

Thornton Bay 

2 

Windy Pt 

Rocky Pt 

Ramp 

Ramp 

1 

Opani point 

Waiomu 

Te Puru 

Tararu 

THAMES 

Tur ua 

Kauaeranga River 

Figure 8-1 Study area and location of 10 transects (sites) and 30 sampling stations at 3 

approximate tidal elevations within the Firth of Thames Ramsar Site and nearby Thames Coast. 

Note: The Miranda near-shore sampling station (see section 2) is approximately beneath the 

letter ‘a’ of station 9a. 

8.2.2 Sampling protocol 

Triplicate samples were collected from all sites on transects 1-2 and 4-9 using a purpose built 

corer. At some stations in transects 10 and 11, only 2 replicate samples were taken because a 

change in sediment composition (hard bottom or coarse sand) made sampling difficult, 

bringing the total number of cores to 85. Each sample represented a surface area of 176.7 cm 2 

(15 cm dia.) and a volume of between 1,767 – 3,534 cm 3 (10-20 cm deep). This discrepancy 

of volume occurred only at six stations where the corer was incapable of penetrating hard 

substrates underlying the soft surface layer. 

In most cases anoxic sediment was encountered within 5 cm of the surface, and frequently in 

the top 1-2 cm. The samples were sieved (0.77 mm aperture) either over the side of the boat 

or back on land, and the large (>2 mm) invertebrates (mainly consisting of bivalves) were 

picked from the sample residue, preserved in 5 % formalin and taken to the laboratory for 

sorting and identification. At most stations there were few polychaete worms, most frequently 

Shell bank 

Kopu

93 

at a size that would have allowed some to pass through the sieve and some to be retained. 

Numbers of individuals were recorded and notes were taken on the composition of the sample 

and, in some instances, the sizes of particular bivalves. 

8.2.3 Statistical analysis 

As was expected, the data on the whole are highly variable and not conducive to doing 

meaningful statistical tests. Even on a subset of data from the most consistently scored 

bivalves, sample variation (SD) exceeds the mean value for each station (i.e. CV > 100%). 

As a result, abundance estimates are drawn from totals of organisms per station. 

8.3 Results 

In total 492 organisms representing 23 different species were recorded (Table 8-1). 

Generally, the total number of taxa (> 2 mm) recorded from each site was low (3-10) but the 

total abundance was often high (up to 250 m 2 ). The biomass extracted from most of the ‘true 

muddy’ sites was also typically very low due to the absence of large bodied species. So at 

sites where bivalves were found, they were easily the most dominant group in terms of 

biomass (e.g. Mactra ovata tristis, station 6a; and Austrovenus stutchburyi, station 8c). 

Bivalves were also the most dominant large-invertebrate grouping by number, with 2-4 

species recorded at all sites except on transect 11, where only two bivalves and three crabs 

were recorded, and on transect 4 where the number of polychaetes (Perineries spp.) 

approached bivalve abundances. However, this statistic is likely to be distorted by the fact 

that small invertebrates (i.e. annelids and amphipods) were not well sampled. 

Live benthic fauna was recorded at all sites except for at 5a and 11b. A notable anomaly 

among the abundances is the uncommonly large (284) number of individuals that were 

recorded at site 12b, located just north of 11b. This was due to the presence of a mat of Asian 

date mussels (Musculista senhousia), which were in densities as high as 6903 to 9166/m 2 . 

Not surprisingly, these abundances correspond to an extremely high Berger-Parker dominance 

measure of 0.97 (Table 8-2). To avoid de-emphasizing the importance of other, less abundant 

species, this recording has been omitted from some figures and diversity indices. 

Although many of the sites revealed very low organic biomasses, densities in some of the 

bivalve-dominated areas (e.g. M. ovata tristis at station 6a) were very high to the point that 

they may be space limited. A scaled representation of the area occupied by the maximumrecorded 

density of M. ovata tristis based on the average size is presented in Figure 8-2 and 

Table 8-3. In these areas there are potentially up to four hundred M. ovata tristis animals per 

30 cm 3 occupying the depth stratum of between 100 and 300 mm. 

8.3.1 Along-shore trends 

Total abundance of animals by transect (3 elevations combined) ranged between 25 and 

245/m 2 (not including M. senhousia on transect 12). Animal abundance peaked at the 

northern-most point on the eastern shore (site 1, Bay south of Tararu, Figure 8-3) and on the 

south-western side of the Firth (sites 7-9) near the Waitakaruru River outlet. Transects 5 and 

11 scored the lowest total abundances (Figure 8-4). 

The cockle (A. stutchburyi) was most common in the central-western upper Firth (transects 7, 

8, and 9, Figure 8-4) and in the channel at the mouth of the Waihou River (transects 2 and 4). 

M. ovata tristis, on the other hand, was only dominant in the central upper Firth (transects 6, 7 

and 8), and Macomona liliana was more prevalent along the western transects (10, 9 and 12). 


94 

Table 8-1 Summary of raw data indicating total number of species recorded at each site (numbers represent a composite of three replicate core samples). 

Transect 1 2 4 5 6 7 8 9 10 11 12 

Site A B C A B C A B C A B C A B C A B C A B C A B C A B C A B C A B C 

MOLLUSCA 

Pelecypoda 

Austrovenus stutchburyi 7 2 12 2 3 1 2 1 10 26 1 10 1 3 

Nucula hartvigiana 7 8 1 1 2 1 

Mactra ovata tristis 1 2 1 8 2 2 6 3 5 2 1 

Mactra ordinaria 1 1 1 1 

Macomona (Tellina) liliana 1 1 3 1 1 2 1 1 2 5 3 1 5 1 4 

Saccostrea glomerata 1 1 

Musculista senhousia 

Gastropoda 

332 

Cominella glandiformis 

ARTHROPODA 

Decapoda 

1 1 

Macrophthalmus hirtipes 1 3 1 1 

Helice crassa 2 

Paratya curvirostris 1 

Elminius modestus p 

Shrimp 

ANNELIDA 

Polychaeta 

1 1 

Perinereis natia var. vallata 1 1 1 4 1 

Perinereis spp. 3 1 2 1 1 

Nephytidae sp. (Aglaophanius macroura?) 1 

Unidentified Polychaete A 1 

Unidentified Polychaete B 1 

Capitellidae p p p p p p p p p p p 

Small Nematode 1 

Nemertine worm (Cerebratulus spp.) 1 


95 

8.3.2 Across-shore trends 

Similar abundances were recorded between shore elevations (stations), with high tide areas 

(stations “a”) recording on average slightly fewer animals than lower elevations (Figure 8-5). 

Stations “b” and “c” recorded exactly the same total densities of organisms (41.4/m 2 ), and 

demonstrate similar group compositions within these totals (both recorded approximately 36 

bivalves/m 2 ). 

The consistently common taxa found in Environment Waikato’s shore sampling programme are 

polychaetes Aonides oxycephala and Capitellidae, and the bivalves Austrovenus stuchburyi, 

Macomona liliana, Nucula hartvigiana and Paphies australis (Turner and Carter 2004). 

Abundances in the lower elevations (stations “c”) were generally higher due to the presence of 

cockle (A. stutchburyi) beds (Figure 8-6). Conversely, the high tide elevations (stations “a”) 

were dominated by populations of the large bivalve M. ovata tristis. M. liliana showed a 

preference for the mid-tidal levels, but was also common in stations “a”. Mactra ordinaria was 

found in low abundances in the mid and upper stations on the western side of the Gulf. Shifts in 

the dominant bivalve species corresponded to a shift in functional feeding groups, from deposit 

feeders in the middle and upper regions, to suspension feeders toward the low tide mark (Figure 

8-7). 

A Berger-Parker dominance measure (Table 8-2) highlights the homogeneous nature of the 

community at some sites, where 36 % of the individuals recorded at stations “a” were M. ovata 

tristis and 74 % at station “c” were A. stutchburyi. This was even more pronounced at 

individual stations (the composite of three cores), where the dominance measures were as high 

as 0.92 for the cockle and 0.87 for M. ovata tristis. 

Table 8-2 Berger-Parker dominance measures for the composite data (30 cores each) of the three 

stations (A-C), plus some selected extreme examples from individual stations (three cores each). 

Nmax N (d) Dominant species 

Station A 24 66 0.36 Mactra ovata tristis 

Station B 25 71 0.35* A. stutchburyi 

Station C 53 71 0.74 A. stutchburyi 

Select examples: 

Station 12b 284 291 0.97 Musculista senhousia 

Station 1a 7 8 0.87 Mactra ovata tristis 

Station 8c 26 28 0.92 A. stutchburyi 

Note: Nmax = number of individuals of most abundant species and N = total number of individuals. 

Therefore: 1 = complete (100%) dominance by one species and near 0 = no dominance by any species. 

Capitellid abundances are not incorporated in this measure. 

*The dominating presence of M. senhousia is omitted from this measure: its dominance is highlighted separately in a selected 

example for its individual station. 

The generally low diversity among the large invertebrates corresponds to very little variation 

between the three tidal elevations. Stations “a” recorded a total of 13 different taxa, and stations 

“b” and “c” both recorded 12. From the 32-33 cores taken at each elevation (11 stations × 2-3 

replicates), only four different bivalve taxa were recorded at the high tide level (stations “a”), 6 

at mid tide (stations “b”), and five at MLWS. Both species of Nematodes (round worms) were 

recorded in the high tide fringes (though comparisons cannot be made due to a sampling regime 

that was not effective for these worms). Densities of crustacean and gastropod species were 

uniform across the three levels. Diversity among polychaetes was lowest in the mid ranges (two 

species) and highest at low tide level (four species). 


96 

Table 8-3 Mean size parameters taken from sub-sample of typical adult specimens. 

Displacement Length Depth Width 

n volume (cc) SD (cm) SD (cm) SD (cm) SD 

Mactra ovata tristis 5 28.6 5.0 58.8 4.8 47.6 2.4 24.5 1.8 

Austrovenus stutchburyi 5 1.1 0.4 21.9 2.5 19.0 2.1 12.7 1.5 

15cm∅ 

Figure 8-2 Scale approximation of size and density of M. ovata tristis as recorded in one core 

sample station (6a). 

Abundance/m2 

300 

250 

200 

150 

100 

50 

0 

Polychaetes 

Decapods 

Crustacea 

Bivalves 

1 2 4 5 6 7 

Site 

8 9 10 11 12 

Figure 8-3 Estimated abundances/m 2 of main benthic faunal groups at each site: Polychaeta, 

Decapoda, Crustacea and Bivalvia. Note: Capitellidae abundances have been omitted because they 

were only scored on a present/absent basis, n = 9 cores 


97 

Relative abundances m 2 

30 

25 

20 

15 

10 

5 

0 

Figure 8-4 Estimated abundance/m2 of the six most prevalent bivalve species recorded per transect 

from 9 × 15 cm dia. cores (3 samples × 3 sites). 

Abundance 

45 

40 

35 

30 

25 

20 

15 

10 

5 

0 

Austrovenus stutchburyi 

Nucula hartvigiana 

Mactra ovata 

Macomona (Tellina) liliana 

Saccostrea glomerata 

Mactra ordinaria 

1 2 4 5 6 7 8 9 10 11 12 

Site 

A B 

Station (Tidal contour) 

C 

Polychaetes 

Crustaceans 

Gastropods 

Bivalves 

Figure 8-5 Estimated abundances (m2) of four main benthic faunal groups for each tidal elevation. 

Sites ‘A’ » MHW, sites ‘B’ » mid tide, sites ‘C’ » MLWS. Note: Oligochaete abundances have been 

omitted because they were only scored on a present/absent basis. 


98 

Abundance 

35 

30 

25 

20 

15 

10 

5 

0 

Figure 8-6 Estimated abundance (m2) of four most prevalent bivalve species recorded for each 

tidal elevation. Note: 9 × 15 cm dia. cores (3 samples × 3 sites). Sites ‘A’ » MHW, sites ‘B’ » mid 

tide, sites ‘C’ » MLWS. 

8.4 Summary & Conclusions 

A B C 


Austrovenus 

stutchburyi 

Mactra ovata 

Macomona 

(Tellina) liliana 

Mactra 

ordinaria 

8.4.1 Community structures 

Though the diversity, and frequently the abundances, of benthic macrofauna (>2 mm) in the 

samples were low, this is predictable considering the sediment type and oxygen limitations. 

Oxygenated sediments in the shallow coastal waters rarely penetrate further than 1-2 cm into the 

mud, thus greatly restricting habitat for oxygen-dependent infauna. 

In some areas however, densities were high and showed some interesting spatial patterns. This 

was mainly due to healthy, almost homogeneous bivalve beds, which exhibited strong 

compositional shifts between tidal elevations. Such spatial patterns were particularly apparent 

at sites 6-10, where the different tidal elevations were heavily dominated by different bivalve 

species. The high tide level (stations “a”) was typically dominated by M. ovata tristis, whereas 

the low tide elevation was dominated by A. stutchburyi. M. liliana was common in the upper 

levels, but most abundant in the mid tide area, and not present at low tide. This is consistent 

with the classical tidally oriented distributions described by Morton & Miller (1972) for these 

species inside of a harbour. 

In the upper Firth, such community composition transformations occur over large distances due 

to the very gentle sloping foreshore. The very large intertidal distances (i.e. between stations 

“a” and “c”), of as great as 2 km, is indeed characteristic of harbour mud flats. It is likely that 

the gradually sloping shore serves to dissipate much of the wave energy a long way out, creating 

estuary-like conditions at the base of the bay, without it being enclosed by a barrier or 

headlands. 

The distribution of species can be described in relation to a number of variables, e.g. tide, 

sediment type, wave exposure and morphological adaptations of the species. M. ovata tristis is 

a suspension feeder that can tolerate fine muds and silts (Morton & Miller 1972, Grange 1977). 

A. stutchburyi, to the contrary, is better suited to cleaner sand. These trends are evident 

inFigure 8-7, which divides into functional feeding groups the majority of the organisms found. 

This pattern is consistent with the findings of previous studies by Larcombe (1971), Dobbinson 

(1989) and Peterson (1991), who identified the low tide areas on enclosed soft shores as the 

preferred habitat for A. stutchburyi. It is therefore possible that a shift in sediment composition 


99 

from fine silts to sandy mud in deeper water (2 m+) is largely responsible for the observed 

change in species composition. Sediment grain size analysis is needed in order to confirm this 

relationship. 

Total abundance 

70 

60 

50 

40 

30 

20 

10 

0 

A B 


C 

Figure 8-7 Dominant taxa divided into functional feeding groups for stations A-C. 

Deposit 

feeders 

Filter feeders 

Scavengers 

Cockle beds (A. stutchburyi) in the lower Firth were typically dominated by a single, small size 

class, suggesting one of three things: age stratification along the shore, recent mass settlement, 

and/or recent mass mortality of adults. Furthermore, many of the sites were primarily 

comprised of small dead shells, also in a single size class. The idea of different cohorts 

occupying different zones on the foreshore is not a new one (Larcombe 1971, Dobbinson 1989, 

Peterson 1991), but it is interesting to note that similar distributions may be present on such a 

gradually sloping mudflat. How these age groups were distributed along the shore was not 

apparent from this survey. If the large quantity of small dead shells is related to a mass 

mortality event as opposed to expiry through old age, it is hypothesised that it may be due to 

rapid shore accretion during large sedimentation events (i.e. they were smothered during a 

storm). Other possible explanations include pulses of pollutants being discharged from 

surrounding streams, or natural environmental extremes such as desiccation from a spring low 

tide occurring in the middle of the day in summer. 

Although the communities were not sampled in full (i.e. individuals of >2mm), it is worth 

noting that the highest species diversity was recorded at sites 4 & 5, which were closest to the 

outlet of the Waihou River. The animals responsible for the elevated diversity were primarily 

polychaetes, an oyster, Saccostrea glomerata, and the shrimp Paratya curviostris. This is likely 

due to a number of factors, such as: a wider array of physical and chemical water properties 

(e.g. salinity, temperature and turbidity) catering for a greater diversity of fauna, advection of 

brackish or even terrestrial organisms from the river mouth, and the presence of varying 

substrates allowing points of attachment for sessile organisms and shelter for others. 

Although the Asian date mussel (M. senhousia) was only recorded at one out of the 11 sample 

sites, its presence this far south is of some concern. It has previously been recorded in high 

abundances slightly further north in the Hauraki Gulf (Tamaki Estuary, at up to 16,000/m 2 ) in 

1997 (Creese et. al. 1997), but apparently has not been reported this far south into the Firth of 

Thames. Since this survey, mats of M. senhousia have been observed washed up on shore at 

several locations near Kaiaua in 1999 following a northeasterly storm, engulfing portions of 


100 

mussel dropper lines that have been in contact with the seabed, and densely colonising the 

seabed beneath a mussel farm near Waimangu Point (October 1999, pers. obsv.). 

8.4.2 Study limitations 

On the whole, the shallow water boat-operated (SWBC) core sampler proved effective, 

providing a fast and relatively efficient means of extracting small samples. However, there 

were some areas where the sampler did not work well. This was primarily due to harder 

bottoms preventing the sampler from penetrating the bottom, or coarser (shell and gravel) 

sediments which were not well retained when the corer was lifted. Sampling at high tide was 

limited, as the length of the corer (200 mm, plus the 2 m pole extension for manually driving it 

into the sediments from the boat)) dictated the maximum sampling depth. 

As there is usually more diversity in the coarser sediments (S. Thrush, NIWA, personal 

communication 2001), the failure of the sampler to perform in that medium means that the 

results reported here can only apply to the fine sediment habitats. Ideally, a Coff-Kyd-like 

sampler (see next section) could be operated from very light shallow draft boats at the margins 

of the tide for sampling the full range of sediment types. 

There were two main types of associations that seemed to be linked to the hard sediment areas. 

The first involved sites directly out from river mouths, particularly those that drain mountainous 

catchments such as the Kauaeranga River. The coarser substrates are likely due to storm-related 

discharge of sediments from the hills. The other extensive patch of firm substrate was in the 

vicinity of the Miranda Chenier ridges (described by Curtis [1981], Woodroffe et. al. [1983] and 

Liefting [1988]), where historic shell banks are layered within the sediments. 

As the main objective was to survey the macrobenthos that serve as food organisms for waders, 

animals smaller than about 2 mm were only occasionally sampled in this study. As a result, the 

abundances of some organisms at the lower end of the size scale were most certainly 

underestimated. This was particularly the case with a small, red Capitellid polychaete worm, 

which was abundant at some sites, and in places may have been the dominant species by 

number. Also nematodes and oligochaetes are unlikely to have been fully sampled. A follow-up 

study should be conducted which would sample everything >0.5 mm in order to properly 

quantify the significance of fauna in this size class. 

8.5 Recommendations 

It is recommended that a more comprehensive survey be conducted in the shallow waters of the 

Firth of Thames Ramsar Site to provide a clearer picture of the composition and relative 

abundances of the keystone in-faunal communities that were recognised by this survey and the 

following study (Section 2). Some insights into the relationships between these mudflat 

invertebrates and the waders at Miranda were provided in a 1999 study undertaken by the 

Miranda Naturalists’ Trust (unpublished), and by Anderson (2003). The Farewell Spit study 

(Battley, et.al. 2004) contributed valuable information about the infauna of a similar habitat, 

some improved sampling methodology, and some useful interrelationships between the 

invertebrates and their wader predators. A more systematic study, using widely accepted 

methodologies and designed for making comparisons with other similar environments, would 

prove particularly useful with regard to future state of the environment monitoring in the 

Waikato and Auckland Regions. 

The area’s role as the primary receiving environment for most of what goes down in the vast 

(3600 km 2 ) Hauraki Catchment suggests that it is an ideal location for monitoring the 


101 

cumulative downstream effects from wider activities and natural events. The study should 

include: 

• a corresponding sediment analysis study, including information about grain size, ash-free 

dry weight content (AFDW) and redox-discontinuity layer depths, 

• more samples from the hard substrate areas where the SWBC corer was only partially 

effective, 

• an increased number of strategically placed sites around the foreshore, 

• detailed information on Capitellid abundances throughout the area, 

• sampling and recording all individuals >0.5 mm, and more focus on taxonomy 

• a revised number of replicates (or replicate strategy) with a view to obtaining some useful 

statistics on abundances (to give more meaningful average density figures), 

• include some size and weight information on the dominant species (to allow biomass 

assessments and comparisons), 

• a fourth ‘station’ (subtidal) should be incorporated in order to gain information on how the 

communities change as they benefit from full tidal immersion, 

• more integration with related studies is needed, particularly some that address the feeding 

behaviour of the principal Miranda wader species in other parts of the world. 

Ideas for useful related studies include: 

1. Work on the distributions of the exotic, mat-forming date mussel, M.senhousia, in the Firth 

of Thames (an extremely effective competitor with some of the principal invertebrate 

species). Does it exhibit the previously described boom and bust type existence as in the 

Hauraki Gulf? Where was the likely source, and what was the likely mechanism of 

introduction? What impacts does it have? Initial works could focus on: 

• studies on distribution, abundance and population dynamics, 

• a study on the abundance of associated con-specific bivalves inside and outside 

the matted areas (con-specific bivalve abundances can be reduced by its presence), 

• a study comparing biodiversity inside and outside of matted areas, and 

investigation into the potential impacts to the natural character of the area and to the 

existing endemic flora and fauna, 

• an investigation into the potential impacts of aquaculture in the neighbouring 

areas (Waimangu Pt., Coromandel, Wilson’s Bay) 

2. Localised intensive studies to gain estimates of average densities and biomass of all or part 

of a faunal assemblage (dominant bivalves and worms) in designated areas of interest (this 

would mainly correspond with known wader feeding sites), 

3. Application of a standard sampling approach formulated by Ministry for the Environment, 

EW, ARC and NIWA for the study of benthic communities in this region, 

4. Note: Both ARC and EW in their long term monitoring programmes use 13 cm diameter 

PVC cores, 15 cm deep, for all benthic sampling (sieve 0.5 mm). This approach should be 

considered for any further studies, as these organisations are unlikely to change their 

methodologies for existing sampling programmes. Alternatively, the Ministry of Fisheries' 


102 

approach is transects and quadrats for monitoring shellfish populations. They are also 

unlikely to change their long-established approaches. And, the highly relevant Farewell 

Spit study (Battley et.al. 2004) employed a 10 cm. corer, 25 cm. deep, and a sieve size of 

1.0 mm (results from different corer diameters can be adjusted, but the corer depth and 

sieve size needs to be standardised), 

5. Following on from the intensive study, to conduct predator exclusion studies in an attempt 

to determine the food supply for migratory birds on the Miranda foreshore and to assess the 

effects and grazing rates of wading birds on the supporting benthic communities, 

6. An intensive study over an across-shore gradient to determine spatial relationships of the 

three most dominant bivalves: M. ovata tristis, A. stutchburyi, and M. liliana with distance 

off shore, 

7. Size-frequency distributions of one or more of the dominant bivalve species down the shore 

and along the shore, possibly combined with some age verification work. Also, establish a 

similar monitoring regime on a known cockle bed. These would aim to determine the 

survival rates of key invertebrate species in the face of predation by birds and fish, and 

natural mortalities due to sedimentation, physical events and disease. 

Section 2 - Miranda near-shore benthic fauna studies 

by Peter Maddison and Nigel Keeley 


Like the greater lower Firth of Thames, the benthic fauna of the intertidal mudflats at Miranda 

(Figure 8-1) has remained largely unstudied. EW monitors this area on quarterly basis, but so 

far only one report summarising the research results from 2001 to 2002 is available (Turner and 

Carter 2004). One study (Sandler 1999) was conducted in the bird wading areas in this region, 

with the intention of examining the animals associated with certain substrate types. . However, 

this work is incomplete and the results are not likely to be formalized. A preliminary broad 

scale investigation into the benthic communities of the lower Firth of Thames Ramsar site also 

included some sites near to Miranda (see Section 1). However, firmer substrates encountered 

over the bird wadding areas prevented effective sampling of those communities. Two of the 

recommendations that came from this work were for: 

• localised intensive studies to gain estimates of average densities and biomass of all or part 

of a faunal assemblage (dominant bivalves and worms) in a designated area of interest, 

potentially corresponding to known wading bird feeding sites, 

• to standardise benthic sampling techniques 

A sampling programme was developed to begin to address these two aspects. Accordingly, the 

concise objectives were twofold; firstly, to compare the efficiency and effectiveness of different 

sampling methods and at different sampling times (i.e. exposed at low tide versus covered at 

high tide) to determine the best technique for future studies, and secondly, to better describe the 

principal animals present in the intertidal mudflat community opposite the Findlay Reserve (just 

north of the mouth of the Miranda Stream). 


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8.7 Study site 

Sampling took place in the upper to mid-tidal region of the Miranda foreshore, in an area 

exposed by the tide 2.5-3 hours after high tide. The site was selected based on observations of 

the areas used by the wader species (godwit, knot, oyster-catcher). The area was also close to 

the site used by Sandler in 1999 for comparative purposes: 215 m in an easterly direction from 

the bird hide (see map, Figure 8-1). Plots of 10 m ×10 m were marked out using bamboo poles. 

8.8 Sampling Methods 

Field work commenced in March 2001. The first experiment was aimed at testing different 

sampling equipment (Table 8-4): 

Table 8-4 Description, sampling technique and sample volume associated with each sampling 

device. 

Sampler 

Description 

Technique 

Eckman-Birge Dredge Grab dredge Drop and grab 

Corer 1 (13.5 cm. diameter, metal) Pushed into mud 

Corer 2 (13 cm. diameter, PVC) Pushed into mud 

Coff-Kyd Scooper (metal rectangular box, 30 cm. 

× 15 cm.) 

Pulled horizontally through 

the substrate 

Volume 

(l) 

4.8 

Ten samples were collected with each device from the marked plots. The first series was taken 

at low tide when the plots were exposed. Disturbances were minimised by using planed routes 

to and from the sampling plots. Samples were removed from the device and put straight into 

double thickness plastic bags and transported to the research site within the hour for processing. 

To test the efficacy of the sampling devices when the plots were covered by water, samples 

were also taken approximately 2.5 hours after high tide. In this situation the plots were covered 

by c. 30 cm of water at the commencement of sampling. 

Each sample was put through in a 45 cm dia. sieve (mesh size 1 mm) inside a container with 

rainwater to a depth of c. 4 cm (note: this may have caused swelling of some estuarine species). 

The residue was examined for organisms. Living molluscs and crabs were collected and 

measured - their epizootic fauna and that on empty shells (sponges, Bryozoa, barnacles, 

anemones) was noted. The empty shells and other large debris were examined for the presence 

of organisms, such as annelid worms. These plus organisms from the surface of the sieve were 

transferred directly to tubes with 70% ethanol. 

Samples were examined in the laboratory and were sorted into different taxa. Some organisms 

were identified to species level; others were characterized according to their family, order, class 

or phylum. Estimates of organism and taxa abundances were then standardized to 1 litre of 

sediment, according the approximate sampler volumes (Table 8-4). Note: these were not 

analysed in terms of depth categories. 

8.9 Results 

8.9.1 Method comparison 

Total numbers of organisms and taxa recorded by each sampling device is shown in Table 8-5. 


1.9 

2.1 

5.7

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Table 8-5 Comparison of sampling devices when plots were exposed and submerged. Standardized 

to 1 litre of sediment [Organisms are totals of ten samples, collected in March 2001.] 

Device Vol.* (l) Total Organisms No. of Taxa 

Substrate: exposed submerged exposed submerged 

Dredge 4.8 218 395 16 14 

Metal Corer 1.9 188 246 14 17 

PVC Corer 2.1 173 189 17 14 

Coff-Kyd(1) 5.7 486 1313 16 18 

Coff-Kyd(2)+ 5.7 936 839 25 23 

* The volume figure relates to the available volume if the device was "full". In practice this is 

rarely achieved. + A second series of samples was taken with the Coff-Kyd sampler. 

The Coff-Kyd Scooper sampled the highest numbers of organisms, and recorded the highest 

biodiversity (Table 8-6). 

Day 1 

Table 8-6 Two way ANOVA comparing variance associated different methods and sampling tides 

(exposed and covered) on day 1 

df MS F Sig. 

Tide 1 97526.017 26.153

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Table 8-8 Total for organisms collected in ten Coff-Kyd samples in Plot A – March, June and 

September 2001. Volume standardized to 1 litre of sediment. 

Organism March 2001 June 2001 September 2001 

Macomona liliana 120 127 136 

Austrovenus stutchburyi 10 9 64 

Helice crassa 32 2 35 

Elminius modestus 26 22 7 

Orbinia papillosa 165 89 70 

Magelona papillicornis 7 9 35 

Nicon aestuariensis 16 67 32 

Glycera lamellipodia 0 16 342 

Capitellidae - - 176 

Total individuals 427 411 958 

Some changes in abundance are noteworthy - particularly for the Burrowing Mud Crab, Helice 

crassa. Table 8-9 lists the taxa recorded to date. 

Table 8-9 List of Taxa found in Benthic Fauna Samples at Miranda. 

Phylum Class or Family Species 

PROTOZOA Actinopoda 1 species 

COELENTERATA Hydrozoa Amphisbetia bispinosa 

Anthozoa Anthopleura aureoradiata 

Edwardsia tricolor 

1 indet. species 

ASCHELMINTHES Nematoda 2 species 

ANNELIDA Oligochaeta 1 species 

Echiuroidea 1 species (?) 

Polychaeta Orbinia papillosa 

Glycera lamellipodia 

Magelona papillicornis 

Nicon aestuariensis 

Pectinaria australis 

Capitellidae 1 species 

Spionidae 2 indet. species 

Nereidae 1 indet. species 

Sipunculidae 1 indet. species 

BRYOZOA Hippelozoon novaezelandiae 

ARTHROPODA Crustacea Elminius modestus 

Amphipoda Caprella sp. 

1 indet. species 

Isopoda 1 species 

Decapoda Helice crassa 

Halicarcinus whitei 

ECHINODERMATA Holothuroidea Trochodota sp. 

MOLLUSCA Bivalvia Austrovenus stutchburyi 

Macomona liliana 

Gastropoda Cominella glandiformis 

CHORDATA Ascidiacea 1 species 

Hemichordata (Acorn worm) 


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8.10 Discussion 

Of the four devices tested, the Coff-Kyd scooper was found to yield the most consistent results, 

and also the greatest number of organisms. However, as the Coff-Kyd sampler functions as a 

scoop, its results are skewed: it samples more animals because it mainly collects surface 

sediments, with a diminishing representation of deeper sediments. Thus, the device is less 

accurate because it doesn't sample a standard surface area with depth, and extrapolations to 

abundance / m 2 are therefore not possible. Likewise, comparisons with other studies are not very 

feasible. 

A recent quantitative survey by Battley et al. (2004) of the benthic fauna of Farewell Spit, 

Golden Bay, has shown several similarities with the Miranda mudflat fauna. This survey was far 

more extensive and covered grid-sampling of approximately 10,000 hectares in March 2004. 

Ninety-one taxa of invertebrates and fish were recorded. The dominant species was the Cockle, 

Austrovenus stutchburyi. Amongst the Polychaeta, Spionidae and Capitellidae were frequent, 

though it would seem that numbers of Orbinia and Nicon were far less than at Miranda. This 

could be due to the limited time frame in which this Farewell Spit survey was conducted (15-28 

March 2004). This study however suggests several possible areas where research at Miranda 

could prove useful, particularly in the study of invertebrate/bird interactions. 

8.11 Continuation of the study 

Initial studies – refining the methodology: 

• Define situations in which the Coff-Kyd sampler would be the preferred methodology, 

• Take a series of benthic samples at different states of the tidal cycle to identify best 

and/or easiest/most efficient sampling time, 

• Determine sampling regime – numbers of samples/effort to reduce variability. 

• Conduct vertical ‘belt’ transects across the mudflats at Miranda – record physical 

features, bird activity, times of exposure, etc. [Ideally this should be designed to show 

changes in benthic fauna but the terrain with its channels and shell banks overlay the 

vertical gradients.] Determine interval of sampling that shows variations in faunal 

groups – the normal method of doing this is to start with the sampling points widely 

separated and then infill details. 

• Re-check identifications of Miranda material against Farewell Spit/Leigh specimens. 

• Analyse and dissect any dead wader birds for gut contents, condition of organs, 

parasites, etc. 

Field Work: 

• Set up a series of sites that will be monitored on a two-monthly basis for fauna. Record 

abundances and size frequencies over time, 

• Include more intensive sampling periods at times just before and just after wader bird 

arrival and departure. 

• Set up a survey grid (as in the Farewell Spit study) to map distribution of organisms 

over a sample segment of mudflats – this will depend on other studies above, but ideally 

should encompass the shore out from established mangroves and shell banks, and 

include at least one coastal stream habitat. In this survey grid, the following features 


107 

should be mapped :physical and human-related features, vegetation, stream channels, 

sediment type and depth of anoxic layer, bird activity zones, fish activity over the area, 

benthic fauna. 

• Set up small comparison sites at sites within Firth of Thames, and sites further afield 

(e.g. Kaipara, Manukau, Tahuna Torea, Tauranga Harbour, Foxton Estuary and 

Farewell Spit) to get a picture of whether what is happening in the Firth of Thames is 

being matched elsewhere. 

• Develop an educational kit to provide students with simple methodology and keys, to 

assist with undertaking safe soft shore biological studies. 

Summation: 

The long term goal of this work is to develop a synoptic focus for the study of benthic fauna in 

New Zealand, with particular emphasis on their interactions with birds and fish. The wader 

birds feeding on the mudflats are key indicator species of the health of coastal environments. 

Internationally many species are migratory – and five New Zealand sites, including the Firth of 

Thames, form part of the Australasian-East Asian Flyway. Nationally, these coastal areas 

include habitats for unique native birds such as the Wrybill and New Zealand Dotterel. In order 

to achieve effective long-term management of these species, a much deeper understanding of 

the dynamics of the benthic fauna communities is required. 


108 

9 Land Tenure / Statutory Management 

by Bill Brownell, Scott Bogle, Rosalind Wilton and Stella Frances 


This chapter outlines the land tenure status of the Firth of Thames Ramsar Site and the 

framework which governs the statutory management of the designated 8,500 hectare area and 

the adjoining land and sea. It also identifies the principal land management considerations 

relating to it and comments on the adequacy of existing policies and plans to provide the 

“protection in perpetuity” envisaged by Section 32 of the Hauraki Gulf Marine Park Act 2000. 

9.2 Land Tenure 

The Ramsar Site lies within the Coastal Marine Area (CMA). The Resource Management Act 

defines the CMA as extending from the line of mean high water springs out to the 12-mile limit 

of coastal waters. The CMA of the Firth of Thames also includes the tidal first kilometre of the 

Waihou River (measured from the top of the stopbank at the margin of the Firth, and proceeding 

upstream from there), and a distance upstream from the mouths of the Piako and Waitakaruru 

Rivers that equals five times their respective widths at the mouth. The CMA is vested in the 

public of New Zealand and therefore ‘owned’ by the Crown (New Zealand Government) as 

asserted by section 13 of the Foreshore and Seabed Act 2004. 

All of the land in the band between the coast road and the seaward edge of the stopbank is 

owned by private farmers. For the entirety of this Ramsar Site the limits to the coastal 

environment are clearly defined by a physical barrier: the stopbank that runs from the 

Kauaeranga River at Thames in the east right around to the Hot Springs Drain in the west, and 

then defined by the coast road continuing on to Kaiaua. 

9.3 Legislation 

The principal legislation governing activities within the Ramsar site are the Resource 

Management Act (RMA) 1991, the Hauraki Gulf Marine Park Act (HGMPA) 2000, the Local 

Government Act (LGA) 2002, the Fisheries Act 1996, the Crown Minerals Act (CMA) 1991, 

the Biosecurity Act 1993 and the Wildlife Act 1953. Management of conservation and reserve 

land in the catchment is governed by the Conservation Act 1987 and the Reserves Act 1977. A 

brief outline of principal legislation (excluding the HGMPA and LGA) is provided in the State 

of the Environment Report (1997). 

9.3.1 Hauraki Gulf Marine Park Act 2000 (HGMPA) 

The HGMPA recognises the national significance of the Hauraki Gulf, and is a separate NZCPS 

established to facilitate more effective integration of all of the policies, management tools and 

cultural values that are collectively meant to control the use, development and conservation 

within the Hauraki Gulf Marine Park and its catchment. 

The purposes of the Hauraki Gulf Marine Park (Section 32) are particularly relevant to the 

Firth of Thames Ramsar Site. They are as follows: 

• to recognize and protect in perpetuity the international and national significance of the land 

and the natural and historic resources within the Park; 

• to protect in perpetuity and for the benefit, use, and enjoyment of the people and 

communities of the Gulf and New Zealand, the natural and historic resources of the Park 


109 

including scenery, ecological systems, or natural features that are so beautiful, unique, or 

scientifically important to be of national significance for their intrinsic worth; 

• to recognize and have particular regard to the historic, traditional, cultural, and spiritual 

relationship of tangata whenua with the Hauraki Gulf, its islands and coastal areas, and the 

natural and historic resources of the Park; 

• to sustain the life-supporting capacity of the soil, air, water, and ecosystems of the Gulf in 

the Park. 

The Act also establishes the Hauraki Gulf Forum, of which the objectives are: 

• to integrate the management, and where appropriate, to promote the conservation and 

management in a sustainable manner, the resources of the Gulf, its islands, and catchments; 

• to facilitate communication, co-operation, and co-ordination between management 

agencies; 

• to recognise the relationship of tangata whenua within the Hauraki Gulf 

An interim performance review of the Forum’s first four years of operation was completed in 

September 2004 (Willis, 2004). The general conclusion of this review is that the Forum has 

fallen far short of expectations, and it lists a number of improvements that need to be made if 

the Forum is to realise its promise. 

The Hauraki Gulf State of the Environment Report draft released in September, 2004 

(Moore, Willis and Dickie 2004) is a third pillar of the HGMPA: an attempt to define the 

physical, social and biological nature of the Gulf, plus the threats to its sustainability and 

measures that can be applied to manage these. A final version is due out in 2005. 

9.4 Statutory Management 

At least eight different central and local government agencies have either direct jurisdiction or 

significant influence on the administration of public activities and regulation of private activities 

in the site under the legislation identified above. 

This section describes the jurisdictional area and functions of each agency, and the legislation, 

policies and plans which guide decision making on undertaking public works and services and 

regulating private activities. The map, Figure 1.1, shows the jurisdictional boundaries of the 

government agencies involved. Table 9.1 lists the strategic, policy and planning documents 

which apply within the different administrative areas. Figure 9.3 shows the relationship between 

plans and policies developed under the RMA. 

The responsibility of Government agencies relating to resource management can be seen as two 

main roles: 

• Firstly they decide how to spend public money gathered through taxes and rates to 

undertake or provide for public works and services for the community, 

• Secondly, they regulate the activities of private individuals on behalf of the public to 

ensure that activities do not adversely affect the environment and the social and 

economic well-being of the wider community. 

The principal agencies of Central Government responsible for coastal policy development and 

implementation are the Department of Conservation, the Ministry for the Environment and the 

Ministry of Fisheries. The New Zealand Coastal Policy Statement (NZCPS) provides the 

principal framework for decision making, with the HGMPA serving as a specific NZCPS for the 

Ramsar Site (as a key component of the wider Hauraki Gulf that is dealt with under this Act). 


110 

The New Zealand Biodiversity Strategy, the Oceans Policy development process and the 

National Environmental Performance Indicators project are key points of reference in defining 

the issues and pointing to appropriate management approaches. 

The Department of Conservation regulates activities in the conservation estate under the 

Reserves Act, for example by issuing concessions for commercial activities. Also, the Minister 

of Conservation, under the Resource Management Act, is the decision maker for resource 

consents in the CMA which are classed as Restricted Coastal Activities (RCA). Restricted 

Coastal Activities are identified in the NZCPS as those considered likely to have a significant or 

irreversible adverse effect on the CMA. 

Both Regional and Local Government undertake this decision making in accordance with the 

Local Government Act 2002 (LGA). Activities and expenditure of the Councils are set through 

the Long Term Council Community Plan (LTCCP) after community consultation. The LGA 

encourages a partnership approach between Regional and Local Government, tangata whenua 

and local communities. The types of works and services which may be undertaken may also be 

indicated in the policies and plans developed under the Resource Management Act such as a 

Regional Policy Statement (RPS) and Regional Coastal Plan (RCP) and District Plan. 

Local and Regional Government regulate private activities through the Resource Management 

Act, primarily through the issuing of resource consents for activities and then monitoring the 

activity where needed. The RPS, RCP and District Plans, provide guidance for this decision 

making by identifying objectives, policies and rules. Regional Government also regulates 

peoples’ use of the water for navigation safety under the Navigation Safety Bylaw. It also 

requires landowners to manage pests and weeds under the Regional Pest Management Strategy. 

District Councils may have bylaws which regulate public safety and nuisance issues (such as 

litter, fires, control of dogs etc.) under bylaws made under the Local Government Act 2002. 

The sections below provide further detail on the functions, policies and plans of Government 

agencies which are relevant to the Ramsar site. 

9.5 Functions, Policies and Plans 

9.5.1 Central Government 

The Minister of Conservation administers the CMA as an agent for the Crown. (S)he also has 

responsibility for the approval of the Waikato Regional Coastal Plan (which has jurisdiction 

over the Ramsar site), as well as decisions regarding Restricted Coastal Activities. 

The Minister of Conservation administers the NZCPS, which provides national guidance to 

achieve the sustainable management of natural and physical resources within the CMA, and 

sections 7 and 8 of the Hauraki Gulf Marine Park Act (2000) which are also an NZCPS in their 

own right. 

The Minister also administers the New Zealand Biodiversity Strategy which was launched by 

the Government in February 2000. Key actions to protect coastal biodiversity relevant to the 

Ramsar Site identified in the Biodiversity Strategy include: 

• improving knowledge of marine and coastal biodiversity and the threats to it; 

• better coordinating management of activities that affect the coastal environment, 

including land-use practices, coastal recreation, fisheries, and pollution; 

• expanding the network of marine protected areas to maintain and restore the character 

of priority sites. 


111 

Important resource management actions include providing information to land users and local 

authorities on measures to mitigate adverse impacts of land use on coastal biodiversity; and 

implementing ecosystem-based sustainable management of commercial, recreational, and 

customary fisheries. The Biodiversity Strategy is being implemented through the activities of 

central and local government, iwi, NGOs (non- governmental organizations), communities and 

individuals. 

9.5.2 New Zealand Coastal Policy Statement (NZCPS) 

The NZCPS has been under review in 2003-4 as mandated by the initial version in 1994 (Rosier 

2004), with the objectives of: 

• Summarising the emerging issues in coastal management and assessing the adequacy of 

NZCPS policies in addressing these; 

• Examining how NZCPS policies have been implemented through plans and resource 

consents; 

• Consulting with users from government, industry and other organisations about 

implementation of the NZCPS; 

• Making recommendations to the Minister of Conservation for the need, if any, to review, 

change or revoke any policies of the NZCPS. 

In light of the new Aquaculture Reform Act 2004, the Foreshore and Seabed Act 2004, the 

recent changes to fisheries allocations and rights under Te Ohu Kai Moana, and the pending 

RMA Amendment Bill and Marine Reserve Amendment Bill, there will most certainly be some 

significant changes to the NZCPS. The new policy is targeted to be finalised in mid-2005. 

9.5.3 Conservation Management Strategies 

The Department of Conservation is divided into 14 Regional Conservancies which administer 

Conservation Management Strategies (CMS) prepared under the Conservation Act 1987. The 

Auckland and Waikato Conservancies meet in the Ramsar site at the Miranda Stream. 

The Auckland CMS identifies the coastal reserves adjoining the Ramsar Site collectively as one 

of 26 key areas for conservation management within the Auckland Conservancy. Objectives for 

Miranda (Taramaire) Key Area target protection of interests of tangata whenua, protection of 

wader habitat, important geological and geomorphological values including the Miranda 

Chenier plain and Whakatiwai gravel ridges, and opportunities for people to appreciate and 

learn about the wildlife and unique natural features of the Miranda coast. The Auckland CMS 

notes that “while the Miranda//Kaiaua coastline is well recognized for its habitat values….only 

a relatively small area is formally protected. The coastline adjoining this area is worthy of 

assessment for potential marine reserve status.” 

The Waikato CMS does not specifically address the Ramsar Site, however the possibility of 

some type of marine protection for the area is under active consideration by the conservancy. In 

a recent NIWA report commissioned by the Waikato Conservancy (Lundquist, et al 2004), only 

the area of the Ramsar site between Miranda and Kaiaua (which sustains the vast majority of 

migrant waders) is recommended for specific protection. However, DoC is also considering the 

importance of the rapidly evolving mangrove ecosystem between Miranda and the Waihou for 

its unique biological and physical qualities. 


112 

9.5.4 Plans under the Fisheries Act 

The Ministry of Fisheries is responsible for sustainably managing the biological resources of the 

Firth of Thames aquatic ecosystem and the commercial, recreational and customary fisheries 

that depend on them. This includes the coordination of research on the status of key fish and 

shellfish resources, their critical ecological parameters (growth, recruitment, feeding habits, 

food availability and interactions with other species) and environmental effects on estuarine 

biota. Information from this research and catch data is used to implement the fisheries 

management system, including the setting of quota for individual species and the development 

of geographically-based management plans for individual quota species. Fisheries plans 

affecting the Ramsar site are those involving snapper, rig, eels, flounder and kahawai. 

9.5.5 Regional Government 

The Ramsar site is situated within the Regional authority of the Waikato Regional Council 

which goes by the name of Environment Waikato. The boundary between Waikato and 

Auckland Regions coincides with the northwestern limit of the Ramsar Site. 

Under the Resource Management Act - Section 30, the functions of Environment Waikato 

include (in conjunction with the Minister of Conservation) the control of: 

• land and associated natural and physical resources (land in this context means the 

foreshore and seabed of the CMA) 

• occupation of space of foreshore and seabed 

• extraction of sand, shingle, shell or other natural material 

• taking, use, damming and diversion of water 

• Discharges of contaminants into or onto land, air or water, and discharges of water into 

water 

• dumping and incineration of waste or other matter, including ships, aircraft and offshore 

installations 

• Effects of the use, development or protection of land (land in this context means the 

foreshore and seabed of the CMA) 

• Avoidance or mitigation of natural hazards 

• Prevention or mitigation of adverse effects of storage, use, disposal or transportation of 

hazardous substances 

• Noise and water surface activities. 

Section 12 of the Resource Management Act prevents anyone reclaiming, draining, disturbing, 

depositing occupying, placing a structure, destroying habitat, plants or animals, introducing 

exotic plants, adversely affecting historic heritage, removing sand shingle, shell or other natural 

material in the CMA, unless it is allowed by a rule in the Regional Coastal Plan, or they have a 

resource consent issued by the regional council to undertake the activity. 

Environment Waikato issues coastal permits for activities which are not permitted in the coastal 

marine area. In making decisions about issuing a permit in the Ramsar site, Environment 

Waikato must have regard to: 

• The overall purpose of the Resource Management Act to promote the sustainable 

management of natural and physical resources, and principles contained in Part 2 of the 

Act; 

• Any actual and potential effects of allowing the activity; and, 


113 

• Relevant provisions of the New Zealand Coastal Policy Statement, Waikato Regional 

Policy Statement and the Waikato Regional Coastal Plan. 

The Waikato Regional Policy Statement (RPS) sets a framework for management of the coastal 

environment and decision making on resource consents. It identifies significant coastal resource 

management issues which relate to the Ramsar site as: 

1. Inappropriate subdivision, use and development within the coastal environment 

resulting in loss of natural character 

2. Any decline in coastal water quality that reduces its life supporting capacity, and/or 

results in decreased cultural, recreational, and commercial value. 

3. Failure to consider the interconnected nature of coastal processes and interagency 

responsibilities may result in unforeseen adverse effects 

4. Conflict between the demand for public access to and along the coastal marine area, and 

the need to restrict access for conservation, safety, security or defence purposes 

5. The emission of excessive noise from within the coastal environment can adversely 

affect amenity and conservation values. 

The proposed Auckland and Waikato Regional Coastal Plans identify policies, rules and other 

methods which guide Council decision making to manage the significant resource management 

issues identified in each RPS. 

The Ramsar site is identified in the Waikato Regional Coastal Plan (RCP) as an Area of 

Significant Conservation Value (ASCV) in terms of natural character, habitat, and coastal 

processes. Most of the activities restricted by section 12 (listed above) within the Ramsar site 

are prohibited activities, for which no resource consents can be sought. 

The Waikato RCP identifies the Firth coastline as a Regionally Significant Coastal Landscape. 

It provides for a staged development of marine farming (mainly mussels and oysters) with a 

focus on the Wilson’s Bay area north of Thames. The Waikato RCP describes a strong 

commitment to the establishment of marine (including inshore) protected areas and community 

care groups. It also sets as an objective the establishment of more effective “cross boundary and 

interagency management of critical environments within the region” such as the Firth of 

Thames. 

The Auckland Regional Plan: Coastal identifies the coastal marine area as the largest public 

open space in the Auckland Region and advocates a precautionary approach where there is 

doubt about the effects of any proposal for subdivision use or development. As was the case 

with the Waikato RCP in 2000, the Auckland RCP is still under deliberation with regard to 

marine farming policy. The mussel farming industry has recently targeted an area of over 5000 

hectares in the Firth of Thames just north of Kaiaua for intensive development, with various 

possible implications for the marine ecosystem of which the Ramsar Site is a part. 

9.5.6 Regional Pest Management Strategies 

The two regional Councils are each responsible for preparing Regional Pest Management 

Strategies (RPMS) under the Biosecurity Act. Strategies identify landowner obligations to 

eliminate or control animal and plant pests. The introduced estuarine grass Spartina is the only 

pest species within the Ramsar site requiring management under the Waikato RPMS. This 

issue has been covered in Chapter 3. 


114 

9.5.7 Territorial Local Government 

Three Territorial Local Authorities (TLA), also known as District Councils, have resource 

management jurisdiction for the landward side of the Mean High Water Springs (outside of the 

CMA), adjacent to the Ramsar Site. These are the Hauraki District Council (HDC), Waikato 

District Council (WDC) and Franklin District Council (FDC). 

Under the RMA their functions include the control of any actual or potential effects of the use, 

development or protection of land, including for the avoidance or mitigation of natural hazards 

and the maintenance of indigenous biological diversity, as well as the control of noise. 

Therefore they have jurisdiction to regulate land use on the private lands immediately adjacent 

to the Ramsar Site (including periodic “spillover effects” into the coastal environment, 

particularly grazing and drain clogging). This includes flood control and drainage matters 

(which mainly occur as a result of agricultural activities). 

The HDC extends from the Waihou River mouth to the boundary with Waikato District at 

Miranda. The WDC manages a relatively small coastal strip near Miranda. The FDC manages 

the strip of coastal environment from the coast road to the edge of the sea (MHWS) for the 

stretch between Miranda Stream and Kaiaua, with the exception of two small, uncovenanted 

private holdings there. 

The Thames Coromandel District Council has responsibility for the densely settled coastal 

environment immediately adjacent to the Ramsar Site between Kopu and Tararu (Figure 9-1), 

including the east bank of the Waihou River. 

The Franklin District Plan identifies the Miranda foreshore as an internationally important 

habitat for birds, and designates all land adjoining the coast as Recreation Reserve. 

The Hauraki District Plan identifies the site as an internationally designated wetland and the 

importance of the area for wading birds. It also notes its value as a recreation resource for 

people involved in ornithology, and as a fish breeding ground supporting commercial and 

recreational fishing in the Firth of Thames. All property bordering the Firth within Hauraki 

District carries a Rural zoning designation. 

A range of non-agricultural uses are considered permitted activities in Rural zones in the 

Hauraki District Plan, including construction of up to two dwelling units per lot, drainage 

works, produce stalls, and limited excavation and prospecting. Discretionary activities subject to 

fairly extensive Council review (i.e. resource consent) include subdivision, certain commercial 

services, industrial activities, and community facilities. Provisions for Rural zones in the 

Franklin, Waikato, and Thames-Coromandel Districts are generally similar to those in the 

Hauraki District. 

A limited amount of land near the coast zoned for residential and business use is clustered 

around the settlements of Waharau, Whakatiwai, Kaiaua, Miranda, Waitakaruru, and Thames. 

Thames is by far the largest urban centre and only centre of light industrial activity in the 

vicinity of the Ramsar Site. Other industrial activities include a gravel quarrying operation in 

Whakatiwai, a piggery on the Waitakaruru River and two large opencast gold mines upstream 

on the Waihou River system near Waihi. 


115 

Figure 9-1 Zoning map of Thames-Kopu area showing Waihou River, Firth of Thames and 

coastal land uses 


116 

A land use survey undertaken in the Hauraki District in 1999 by Worley Consultants found that 

of 78 sites zoned for Heavy Industrial Use, 11 were used for residential purposes, 20 were either 

vacant or occupied by vacant buildings, and the remainder were occupied by a range of mainly 

light industrial and non-industrial operations. Only two heavy industrial operations, both well 

upstream from the Ramsar site (involving noxious, hazardous, or offensive processes and/or 

substances) were recorded. 

In the Hauraki District Plan the area within the CMA carries an overlay designation as a Coastal 

Environment Policy Area, providing for additional assessment and control of proposed 

development. The two objectives for the Coastal Environment Policy Area (CEPA) are drawn 

from the priorities enumerated in the RMA: 

• To preserve the natural character of the coastal environment and ensure its protection 

from inappropriate subdivision, use, and development 

• The maintenance and enhancement of public access to and along the coastal marine 

area, lakes, and rivers 

Activities that are permitted in the underlying Rural zone are also permitted in the CEPA 

overlay provided that they meet the same set of performance standards required of any activity 

in a Rural zone. Activities considered discretionary in the Rural zone (subdivision, commercial 

or industrial development, large scale extraction or excavation, etc.) are subject to a set of 

assessment criteria described below: 

• Whether the natural character of the coastal environment is preserved. Particular aspects 

include: Dunes – Foreshore – Headlands - Coastal vegetation including bush - Streams, 

lagoons, estuaries - Visual backdrop including fields, forest areas, ridges, skylines, 

prominent geographic features - Habitat values - Quietness and peacefulness. 

• Whether the subdivision, use or development is appropriate having regard to the 

objectives of the policy area 

• Whether public access to and along the coastal marine area is maintained and enhanced 

• In the case of proposals to develop forestry, whether activities including land 

preparation, planting, management, silviculture, and harvesting that are to be 

undertaken ensure the visual amenity of the area is not significantly affected. Important 

in this regard are: 

1. The retention of the existing landform 

2. The need to retain existing indigenous vegetation 

3. The need to ensure that areas are planted immediately following ground 

preparation 

4. That harvesting is carried out in sections of a scale such that the visual impact is 

minimized and the land areas so cleared are replanted or otherwise rehabilitated 

within one year of harvesting. 

9.5.8 Reserves 

The Department of Conservation (DoC), Auckland Conservancy, and the Franklin District 

Council share responsibility for managing the strip of coastal environment from the coast road 

to the edge of the sea (MHWS) for the stretch between Miranda Stream and Kaiaua. This is 

mainly a series of reserves, with the exception of two small, uncovenanted private holdings 

there (Figure 9-2). The ecological features are outlined in the Auckland Conservation 

Management Strategy (1996) and in the present chapters 3,4,5 and 7. Immediately north of the 

Miranda bridge, between the coast road and the sea, a 27.7 hectare piece of private farmland has 


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Figure 9-2 Zoning map of Kaiaua-Miranda Coast showing designation and land status (Dept. of 

Conservation and Franklin District Council jurisdictions). 


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been placed with the Queen Elizabeth II Trust under a conservation covenant (Robert Findlay 

Wildlife Reserve) to ensure continued protection of the migratory shorebird habitat contained in 

and around the property. The covenant restricts any development or change in the management 

of the land that would adversely affect the birds or other key features such as the shell and 

gravel ridges of the Chenier plain. There are no reserves or covenants currently covering or 

bordering any of the remainder of the Ramsar Site. 

9.5.9 Drainage Committees 

The West of Piako and East of Piako Drainage Committees are composed of local 

farmers, who make regular recommendations to EW and the HDC about works that 

need to be undertaken, particularly the clearance of drains, and the maintenance of 

pump stations and stopbanks. Such works are permitted activities under the Waikato 

Regional Plan. 

9.6 Treaty of Waitangi matters 

The Ramsar Site is within the rohe of Hauraki and other Tainui iwi and hapu and is an integral 

part of Tikapa Moana. Ancestors of the current tangata whenua lived in close relationship with 

Tikapa Moana since about the 16 th century. The area is part of a claim brought by the Hauraki 

Maori Trust Board under the Treaty of Waitangi, which is currently under consideration by the 

Waitangi Tribunal. Ownership of the Hauraki Gulf foreshore and seabed is also being contested 

in the Maori Land Court. Another claim before the Waitangi Tribunal (Wai 728), challenges 

the Hauraki Gulf Marine Park Act on several counts: first, that the Act fails to give adequate 

recognition to the interests of Hauraki Iwi; and second, that it implements a management regime 

that is inconsistent with the kaitiakitanga responsibilities and the exercise of tino 

rangatiratanga by the various Hauraki Iwi. 

Recent legislation including the Conservation Act, RMA and Fisheries Act set out the statutory 

obligations of central and local government in relation to the principles of the Treaty. Protocols 

for consultation are set out in all district and regional plans. The iwi and hapu of Hauraki 

individually, and through Trust Boards, have developed systems, structures and processes to 

fulfil their kaitiaki responsibilities for taonga within their rohe, including participation in 

processes set out in current legislation. Many of these processes are outlined and discussed in 

the report “Kaitiakitanga and Local Government: Tangata Whenua Participation in 

Environmental Management” (Parliamentary Commissioner for the Environment, June, 1998) 

and the Kaupapa Atawhai strategy of the Department of Conservation (1997). 

The relation of Maori to Tikapa Moana, traditional concepts and management practices, and 

indicators of customary fisheries used by Hauraki Maori were set forth in the “Hauraki 

Customary Indicators Report” (Hauraki Maori Trust Board, 1999). The report stresses the 

integrated and holistic nature of Te Ao Maori, which recognizes the interconnectedness and 

interdependence of all living and non-living elements, or taonga, of the environment. These are 

bound together by mauri, the vital energy or life force that gives being and form to all things in 

the universe. Traditional resource management was based on the idea of sustaining the mauri to 

ensure that the balance was maintained between people and the natural and spiritual worlds. 

The Maori environmental ethic was expressed through the laws of tapu, which involved 

imposing a prohibition or ban on any activity when it was apparent that that activity was 

contributing to a devitalisation of the mauri. The tapu gave time for the mauri to be revitalized 

and restored. The laws of tapu engendered the notion of community responsibility and 

reciprocity toward the natural environment. 


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The decision to impose a tapu is made through the process of rahui (closed season) a 

participatory process exercised by local communities – in particular the tangata whenua, or the 

iwi or hapu with responsibility for a given local area. 

The report defines customary indicators from an analysis of a number of themes, including 

fisheries abundance and use, tikanga Maori (Maori customary practices), seasonal calendars, 

observation, and inherited knowledge. The identification of these indicators is intended to be the 

first step in a three-stage plan by the Hauraki Maori Trust Board to develop an iwi/hapu-based 

monitoring capability for the Hauraki Gulf. Stages two and three will involve defining 

indicators for remaining fisheries not addressed in stage one; defining indicators for freshwater, 

harbour, and coastal fisheries; and designing and implementing a trial project for testing the 

indictors alongside complementary conventional indicators. 

9.7 Strategies, Policies and Plans 

The table below lists the strategic, policy and planning documents which apply within the 

different administrative areas. The key policies and plans directly governing activities in the 

Ramsar site are highlighted with an asterisk. Private land adjacent to the Ramsar site is 

managed in accordance with the relevant Regional Policy Statement, Regional Plan and the 

District Plan zoning that applies. 

Table 9-1 Resource Management Responsibilities 

Policy or Plan Area of application 

Ramsar Convention* Ramsar Site 

New Zealand Biodiversity* 

Strategy 2000 

All biological resources: in particular 

indigenous fauna and flora at ecosystem, 

species, and genetic level on land of all 

tenure, and all of the territorial sea 

New Zealand Coastal Policy Statement* Ramsar Site, surrounding coastal marine area 

and coastal environment 

Auckland Conservation Management Plan 

(CMS)* 

Conservation land within Auckland 

Conservancy 

Waikato CMS Conservation land in Waikato Conservancy 

Fisheries Plans for individual species under 

quota management* 

Auckland Regional Pest Management 

Strategy 

Ramsar Site and designated areas of sea 

(varies with species) 

Auckland Region 

Waikato RPMS* Waikato Region 

Auckland Regional Policy Statement (RPS) Auckland Region 

Waikato RPS* Waikato Region 

Auckland Regional Plan Coastal Auckland Region below MHWS 

Waikato Regional Coastal Plan* Waikato Region below MHWS 

Auckland Regional Plan Auckland Region 

Waikato Regional Plan* Waikato Region 


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Franklin District Plan* Franklin District above MHWS 

Waikato District Plan* Waikato District above MHWS 

Hauraki District Plan* Hauraki District above MWHS 

Thames Coromandel District Plan Foreshore activities around Thames and 

Kopu bordering the Ramsar site 

9.8 Resource Management Act Policies and Plans 

Figure 9-3 Planning Framework of the Resource Management Act 


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9.9 Discussion 

The coast road that runs close to the shores of the Firth of Thames from Orere Point to 

Coromandel was designated the “Pacific Coast Highway” in 1996, and has since become a 

major tourist route for visitors and New Zealanders heading south and east into the country from 

Auckland. The Miranda migratory bird sanctuary has already become one of the principal 

attractions of that route. 

The Kaiaua-Orere Point coast (Fig. 1.1) of the Firth of Thames bordering the Ramsar Site in the 

southeastern corner of the Auckland Region is less than 75 minutes from downtown Auckland. 

The Auckland Region is the fastest growing in the country, containing over 30% of New 

Zealand’s population, and is currently increasing by about 3 % (over 30,000 people) annually. 

Population is now expected to reach 2 million by 2031. 

The remainder of the coast of the Firth is also one of the fastest growing areas in the Waikato 

Region. Thames-Coromandel has experienced the highest growth rate of any district in the 

region, having grown 14.1% between 1991 and 1996. The second highest growth rate, at 12.1%, 

is found in the part of the Franklin District (including the coast between Kaiaua and Miranda) 

within the Waikato Region. The Franklin District as a whole grew 14.5% between 1991 and 

1996, reflecting the growth of the Auckland metro area discussed above. Rapid growth in these 

districts will put pressure on the coastal environment of the Firth of Thames through direct loss 

of habitat and natural character brought by physical development (roads, housing subdivisions), 

as well as indirect impacts such as non-point source water pollution. 

Growth directly along the Miranda – Orere Point and Coromandel coasts has largely come in 

the form of holiday and retirement homes in subdivisions, and larger (4-5 ha.) ‘lifestyle blocks’ 

attracting ‘downshifting’ professionals or Auckland commuters. Thames-Coromandel has 

become a settlement destination particularly for retirees, with 19 percent of the district’s 

population aged 65 and over as compared with 11 percent in that age range for the region as a 

whole. The popularity of the coast for holidaymakers brings with it significant impacts as well. 

The Coromandel receives over 800,000 visitors per year, swelling the population up to ten times 

during the peak summer season. This brings increased traffic, as well as periodic overload on 

sewage systems, which discharge into the Firth. Construction will soon begin on two major 

Waihou River developments at Kopu: a wharf for commercial barges, and a new Coromandel 

Peninsula “gateway” bridge. 

Based on these existing statutes and trends, proposed planning provisions and pending permit 

applications, a number of current and potential threats to coastal and marine ecosystems of the 

Firth of Thames have been recognized: 

• High sediment and nutrient loading, mainly derived from inland farming operations on 

the Waihou, Piako, and Waitakaruru River systems (in spite of considerable progress 

made in recent years by farmers and EW in managing runoff from farms). 

• Demands for wider and straighter roads as facilities designed to handle limited traffic 

from a small rural population become inadequate, potentially causing encroachment 

upon, and redistribution and accretion of sediments within, the intertidal zone. 

• Increased recreational and educational visits by people to key shorebird habitat areas 

and the waters adjacent to them. 

• Effluent outfall from stormwater, sewage, industrial operations, and refuse dumping. 

(largely in Thames and Kopu, and to a lesser degree in Waitakaruru) 


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• Increased marine farming and commercial and recreational fishing pressures, including 

the possible need for quite extensive facilities to support these activities (most likely in 

Thames-Kopu). 

• Intended further drainage, flood control, shore protection, stopbank and riverbed 

improvement works (some of which is on-going, and others in the planning stages). 

• An expanded Thames sewage treatment facility at the mouth of the Waihou. 

Strahan (1997) has noted a number of difficulties in implementing regional and district plans in 

the coastal zone. In particular he identified the difficulty of developing consistent and 

comprehensive planning approaches for the coastal margin and adjoining estuarine and riparian 

areas, as these overlap district and regional council boundaries. While regional coastal plans 

regulate activity up to the mean high water spring tide line, coastal ecosystems may be highly 

impacted by activities well inland that affect water quality in streams and drains feeding into 

coastal waters. Froude (1997) found that relatively few district and regional councils take the 

opportunity to work closely together to coordinate policies for catchment and coastal areas 

(cited in Strahan 1997). 

Froude (1997) also noted that consultation between landowners and district councils has to date 

often been limited and inadequate, as it tends to be time-consuming, costly, and potentially 

confrontational. At regional level, EW has implemented in recent years numerous workshops, 

community care groups, environmental education programmes, technical support in the field 

and direct consultations that have served to increase levels of understanding and information 

sharing with farmers, visitors and other resource users. 

The Hauraki District Plan notes that “other than in the Coastal Marine Area, land use 

management within the coastal environment is the responsibility of the District Council through 

the District Plan” (Section 6.1.1.2). The Plan defines the Coastal Environment as extending no 

further inland than the CMA: “The flat, developed farmland on the landward side of the stop 

bank and Miranda Road does not exhibit any of the characteristics specified in the definition of 

the Coastal Environment in the Proposed Waikato Regional Coastal Plan, nor does it form a 

back-drop to the coastal environment” (Section 6.1.1.3). The Waikato Regional Coastal Plan 

notes that “the coastal environment covers a wider area, and includes the CMA as well as 

landward features” (EW 1997), though apparently not in this case. Thus any development on the 

landward side of the stop bank is not subject to review under the goals, objectives, and criteria 

defined for the Coastal Environment Policy Area. 


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10 Raising Conservation Awareness 

by Bill Brownell, Jan Simmons and Linda Bercusson 


Conservation awareness, education and community initiative activities involve a broad spectrum 

of public and private organizations in the Firth of Thames catchment. The two Regional 

Councils (Auckland [ARC] and Waikato [EW]) have various environmental education 

programmes in place in the surrounding area. The Department of Conservation (DoC) has 

recently placed a particular focus on the Miranda coast. The Miranda Naturalists’ Trust is the 

most prominent locally-based private group that promotes conservation awareness in the 

Ramsar Site. The EcoQuest Education Foundation operates regular university field studies and 

research programmes in ecology and resource management in the area. 

On the national level, the Ornithological Society (and its closely linked Wader Study Group), 

the Royal Forest and Bird Protection Society, and the Fish and Game Council actively promote 

the conservation values of the area. The Hauraki Maori Trust Board has actively supported 

conservation awareness, research and monitoring in Tikapa Moana (Firth of Thames) and the 

associated rivers and lowlands. 

Thames High School, Hauraki Plains College, and the Consortium of four South Auckland 

colleges (that regularly use the area through the Waharau Education Camp) are all using the 

special conservation status of the Ramsar site as effective educational tools. The Kaiaua 

Citizens and Ratepayers group and the Thames Coast Protection Society are just two of many 

local groups that work toward increasing public awareness of the importance of this particular 

Ramsar wetland and the wider Firth of Thames. 

10.2 Department of Conservation 

The Department of Conservation’s mission is “to conserve New Zealand’s natural and historic 

heritage for all to enjoy now and in the future”. Nationwide, DoC is developing new methods 

of getting its message out. 

10.2.1 Auckland Conservancy (general comments) 

Throughout the country DoC conservancies are generally associated with an outstanding 

feature, such as a national park. There are no national parks in the Auckland Conservancy … for 

Auckland the main issue is people and their environment The population of the Auckland 

Region is expected to reach 2 million by 2031, and it will be strongly multicultural. Europeans 

are predicted to make up less than 50% of the population by 2050, with the largest growth 

among Asians and Pacific Islanders. Auckland’s Asian community already exceeds the entire 

population of Hamilton. This population growth and the diversity of peoples’ lifestyle priorities 

will place even greater emphasis on the importance of open spaces and special conservation 

areas. 

In September 2000 DoC received special funding to run an urban conservation awareness 

programme in the Auckland Conservancy. The money was provided from a Vote Conservation 

fund allocated through the Minister of Conservation and the Green Party. 

In all, six initiatives were approved, including: 


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• Conservation Awareness Initiatives and relationship-building with ‘new’ New Zealanders - 

the Asian and Pacific Island communities of Auckland 

• Public awareness initiatives at key conservation sites to raise awareness of the department 

and its work 

• Preparation of conservation site-based teacher resources and networking with Auckland 

educators 

The overall goals of the programme are to: 

• Increase community involvement in conservation 

• Raise public awareness of conservation values and the role of the Department 

This special funding, which has recently been extended for another three years, has allowed the 

Department to develop new approaches to delivering its conservation message. 

The Miranda Wildlife Refuge (Taramaire, the land on the Miranda Coast under jurisdiction of 

DoC) and nearby wetlands play a key role in two conservation awareness initiatives which have 

led to several useful working partnerships: 

10.2.2 Initiatives with Auckland’s Asian communities 

The special conservation awareness funding created many opportunities for working with 

communities new to DoC and the concept of conservation. It provided the means to show, rather 

than tell, why places like Miranda are special and worth preserving. This, in turn, provided the 

stimulus for sustained coverage in a variety of media. 

To launch the campaign the Auckland Conservancy invited influential members of the Chinese 

and Taiwanese communities and media to visit Miranda. For many it was their first 

conservation experience and was made even more meaningful by the connections between Asia 

and New Zealand through the links and active collaborations being established among the 

countries along the Australasian Flyway. As one visitor said: “You cannot underestimate the 

ripple effect of an outing like this. It seems like such a small thing, yet we will all talk about this 

here and when we go back to our home countries.” Miranda is integral to this campaign 

because of these links, as well as the refuge’s proximity to Auckland. 

10.2.3 Conservation Super Sites – Miranda teacher resource kit 

The Auckland Conservancy has produced a series of teacher resource kits to promote 

environmental education at public conservation sites. These are places where young people can 

not only learn about and experience New Zealand’s special natural and historic heritage, but 

also be inspired to take action to help look after it. The kits include site information, 

suggestions for class- and site-based activities and student activity sheets, and provide 

references and links to other information. 

The kits are aimed at primary, intermediate and secondary schools (levels 1-5). They follow the 

Ministry of Education’s Environmental Education Guidelines and take an action-oriented, crosscurricula 

approach. Miranda Shorebird Centre manager Keith Woodley and former Kaiaua 

School principal Sue Reid wrote and illustrated the Miranda kit, in partnership with the 

Conservation Awareness team. Some of the material is suitable for use at other wetland sites in 

New Zealand. 

The first training workshop was held in November, 2001, and will be held regularly to support 

the kit. Teaching material is available online on the DoC website www.doc.govt.nz. 


125 

10.2.4 Waikato Conservancy 

In 2000, the Waikato Conservancy prepared a Learning Strategy, which charts the 

Conservancy’s future direction in conservation education. So far, six site-based teacher 

resource kits have been produced. In addition, conservation awareness materials and resources 

with a focus on the three Waikato Ramsar sites are in preparation. 

The “Community Conservation Infokit (A practical guide for community conservation 

projects)” provides useful information and methodologies for organising and educating 

community groups through specific projects. 

In line with the Learning Strategy, the Conservancy developed another two resource kits and 

facilitated eight teacher workshops (one for each kit) during 2001-2002. One kit is based on a 

wetland theme and explores different types of wetlands, including peat domes, peat lakes, 

kahikatea swamps, riverine and estuarine wetlands, non-peat lakes and swamps. Teachers and 

students have the opportunity to visit a range of sites throughout the Waikato. Assistance is 

provided by the National Wetland Trust, which also coordinates educational events such as 

World Wetlands Day each year in February. 

The second kit is a reserve ecosystem monitoring kit. It includes a variety of monitoring 

techniques that can be easily adapted to local reserves near a school. Ideally, a class or school 

would adopt a reserve and undertake regular monitoring and plan and/or partake in management 

and restoration. 

10.2.5 Partnerships and Communication 

The conservation awareness initiatives have led DoC into several partnerships, including the 

ARC (very active promoters of environmental education), members of the Asian community 

(who have volunteered their time and expertise for tree planting and other hands-on activities), 

as well as prompting discussions with potential sponsors to promote the Miranda Shorebird 

Centre and its work. DoC considers that conservation awareness and education initiatives 

should become an integral part of any biodiversity programme. People are far more likely to 

enjoy (and care for) the environment if they have had positive experiences with / in, and 

sufficient information about the environment. 

The Kaupapa Atawhai Strategy (Department of Conservation, 1997) describes the working 

partnership of Maori and DoC, in the spirit of the Treaty of Waitangi, that particularly applies to 

areas like the Firth of Thames Ramsar Site, which contain important elements of biodiversity 

conservation, customary fishing and historic heritage of concern to Maori. 

10.2.6 Scoping an Integrated, Strategic Approach to Visitor Facilities and 

Services for the south-western Firth of Thames 

Representatives of the Miranda Naturalists Trust, Waikato Conservation Board, Environment 

Waikato and the Auckland and Waikato Conservancies of the Department of Conservation, met 

at Miranda on 11 February 2003 “to explore the potential for working together to provide 

facilities and services for visitors, through a strategic approach to management.” The focus 

was on the south-western corner of the Firth of Thames between Miranda and Waitakaruru. 

It was recognised that various activities are already happening in the area or being planned for 

visitors, including development of a wetland habitat with board-walking and interpretation, 

open days for visitors at Miranda Shorebird Centre as well as day visits by groups/schools, a 

shorebird migration education kit, tourist brochure and signage. Scope was seen for an even 

greater range of activities such as walkway/cycle routes, viewing tower, interpretation of pa site 


126 

and possibly a marine reserve. But there also needs to be a balance between visitor use and the 

protection and enhancement of the natural and historic features of the area. 

Numerous organisations have a variety of statutory roles and responsibilities over the land and 

waters of the area in addition to the community groups, user groups, businesses, individuals and 

iwi that have a collective or personal interest in what happens in ‘their patch’. Various planning 

documents exists e.g. Regional Plans, District Plans and Conservation Management Strategies 

but by themselves, they do not ensure a co-ordinated or integrated approach to the development 

and protection of resources. This can only come from a collaborative and participatory style of 

working, with good communication and understanding between all parties involved. 

Benefits of an integrated approach: 

• Co-ordination of activities/programmes between the various organisations. 

• Agreement on future directions for visitor management. 

• Increased understanding leading to mutual agreement on the features and values that 

need to be protected. 

• Identification of opportunities for joint initiatives in catering for visitors. 

• Potential to share information and combine resources, especially for research and 

promotion. 

• Increased likelihood of maximising visitor satisfaction and minimising visitor impact. 

• Effective use of limited resources and avoiding duplication of services and facilities. 

• Ensuring consistency with planning frameworks. 

• Community participation and buy-in. 

The next step: 

Discuss an appropriate process for achieving a more collaborative, integrated approach to 

managing, developing and promoting visitor opportunities in the area. 

Scope the need to prepare an integrated strategy for visitor facilities and services. Main 

considerations: 

• Who needs to be involved, how can they best input and where should the boundaries of 

the area of interest be i.e. the wider Firth of Thames inter-tidal area or just the southwestern 

corner? 

• How to protect natural, historic and cultural values while providing for their 

appreciation and recreational enjoyment? (This includes natural ecosystems; threatened 

plants; shorebirds, migratory species and forest birds; marine communities; wetlands 

and freshwater habitats; historic sites; cultural connections with the Firth of Thames). 

• How to maximise visitor satisfaction and minimise visitor impact? (This could cover 

the range of opportunities, both current and potential; visitor facilities and access, 

including boardwalks, walkways and cycle tracks; possible use of stopbanks; 

interpretation of natural, historic and cultural values; educational material; resource 

constraints). 


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• Is there a need for more effective promotion/marketing? (Consider brand recognition of 

‘shorebird coast’, target markets; promotional themes; special interest tours or special 

events; research and funding). 

• What options are there for partnerships or possible joint initiatives? 

Recommended Action: 

Miranda Naturalists’ Trust to convene a forum to bring together representatives from various 

agencies and groups with an interest in the area to consider the next steps and how an integrated 

strategic approach to visitor facilities and services could be best achieved. Invitations should be 

extended (but not confined) to local iwi, government agencies, local government, drainage 

board, community groups, tourism industry, tourist providers, recreational users, educational 

organisations and other interested individuals in the local community. 

10.3 Ramsar Convention Work Plan, 2000-2002 

One of the objectives of the work plan was to “To encourage active and informed participation 

of local communities, including indigenous people, and in particular, women, in the 

conservation and wise use of wetlands.” This can be achieved “by establishing wetland 

management committees, especially at Ramsar sites, on which local stakeholders, landowners, 

managers, developers and community interest groups are represented”. No further action has 

been taken on this so far. 

10.4 Other Initiatives 

Many local and national groups publish very informative newsletters about local issues and 

points of interest in the natural world. Four publications of particular note that provide 

coverage of the Firth of Thames Ramsar Site and environs are: Miranda Naturalists’ Trust 

News (41 quarterly issues published to date), Vision Hauraki (the quarterly Hauraki Gulf 

Marine Park newsletter published by the Auckland City Council – 19 issues to date), Policy 

Update (published by Environment Waikato) and DoC’s new Auckland Urban Conservation 

News. 

The Kaiaua Beautification Society has been very active in recent years in planting trees, 

particularly pohutukawa, along the coast between Miranda and Whakatiwai. Many Kaiaua- 

Miranda locals, particularly school children, have turned out on several occasions for tree 

planting exercises (such as the establishment of host plants for mistletoe) on reserves adjacent to 

the Ramsar Site. 

One active Kaiaua-based whanau group, the Pingao Trust, is working on more sustainable ways 

of using and managing collective land holdings, such as organic farming and permaculture. 

There is a particular interest in educating the children in the proper use of the land for the 

benefit of the community and for improving the health and nutrition of individuals. 

10.5 Miranda Naturalists’ Trust 

The Miranda Naturalists’ Trust began with the idea that a birder’s lodge should be established 

near a wading bird roost at Miranda. Members of the Auckland branch of the New Zealand 

Ornithological Society had put forth this idea in 1973, and in the next year a committee was 

convened to study it and take it a stage further. The Auckland Ornithological Society members 

agreed that the establishment of a charitable trust was a good starting point, and ultimately the 

South Auckland Ornithological Society and the Wildlife Service of the Department of Internal 

Affairs joined the initiative to establish the Miranda Naturalists’ Trust. 


128 

Discussions with Allan Lane, the landowner of the historic lime-works site at Miranda, were 

held in 1975, and a lease was drawn up to allow the newly formed Trust access to and usage of 

the lime-works land, as well as the right to place a hide on the land. The Trust subsequently 

purchased land from another nearby landowner to build the Miranda Shorebird Centre, which is 

located close to where the greatest congregation of migratory shorebirds occurs. This facility 

functions as an information and education centre, and has accommodation for up to 30 people. 

Principal aims of the trust are to promote awareness of ecological values in general, and those of 

the Firth of Thames in particular. The centre features displays and dioramas highlighting the 

area’s significant fauna and flora, and a natural history library. Revenue from accommodation, 

sales of books and other souvenirs, and donations are its main sources of income. 

The Firth of Thames is listed as a Reserve site on the East Asian - Australasian Shorebird Site 

Network. The Miranda Naturalists' Trust is a recognised non-governmental organisation partner 

in this network. 

The Trust is actively involved with education programmes for schools and other learning 

groups. In the period 1993 to 1998 over 9,000 school children visited the Shorebird Centre. 

10.6 Improving Interpretation, Access and Advocacy 

The only existing facility dedicated to providing visitor information and access to any part of 

the Ramsar Site is the Shorebird Centre of the Miranda Naturalists’ Trust, and the emphasis 

there is strongly on wader birds. 

A National Wetland Centre is being developed at Rangiriri near Te Kauwhata in the heart of the 

extensive Waikato Wetlands southwest of the Firth of Thames. This initiative is sponsored 

jointly by the National Wetland Trust, the Auckland/Waikato Fish and Game Council and the 

Department of Conservation. One proposal associated with it is a wetlands walkway that would 

extend out from the Whangamarino and Kopuatai Wetlands (both are also Ramsar sites) and 

follow the Firth of Thames coastline eventually as far north as Kaiaua. 

A small foreshore walkway in the Thames township (so far extending from the boatyard at the 

“port” north to Albert St. has been jointly developed by TCDC, Forest and Bird and DoC. There 

is a bird hide with interpretation panels set up by Forest and Bird. It is heavily used by the 

public. It is proposed that this walkway will eventually be extended north to Tararu and south to 

the Waihou River. 

Other potential locations for walkways, hides and interpretation panels to provide the public 

with outdoor recreation and education about the Ramsar Site and its features are: 

• Orongo Road – the historic west bank of the Waihou 

• Shelly Beach Road – east bank of the Piako 

• Buchanan Road – west bank of the Piako (used currently by many recreational fishers 

and duck hunters) 

• Appletree Pump – long, relatively dry access to 800 m wide mangrove forest through a 

salt marsh that is slowly evolving into the next stage of succession 

• The stop banks on either side of the Waitakaruru River 

• Karito Canal south bank (the 1998 dredging spoils allow for relatively firm walking) 


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The Kaiaua Citizens’ and Ratepayers’ Association (in conjunction with DoC, EW, FDC, 

EcoQuest and the Miranda Naturalists’ Trust) will be making application in 2005 for the 

establishment of an upper Firth of Thames Environment Centre at Kaiaua. 

10.7 Support for Research and Advocacy 

Both the Miranda Naturalists’ Trust and its close neighbour, EcoQuest Education Foundation, 

have a strong interest in promoting further scientific research on the Firth of Thames, 

particularly under an ecosystem approach which aims to put a global perspective on the 

numerous physical and biological forces at work throughout the catchment … an ambition fully 

supported by the Department of Conservation. 

Funding is a limiting factor, particularly with regard to work that can be most effectively carried 

out at the local level. Most research funding goes to commercial contractors, who usually take 

little account of local issues and knowledge. When they do, it often involves picking the brains 

of local individuals and the knowledge base of local organisations, and then getting paid 

handsomely for recycling this information. Some funding has been granted by MfE and DoC to 

local Iwi groups for research into cultural history and customary indicators. 

Various discretionary funds are available through the two regional councils, TCDC, HDC and 

the Ministry for the Environment for a range of environmental initiatives with a focus on 

education, and some scope for carrying out local research and documentation of significant 

local knowledge. 

The main constraint is the limited availability of local leadership and initiative to build effective 

(essentially voluntary) organisations, mainly because in today’s world people can’t afford to 

donate the huge amounts of time and expertise required to organise people and systems, to carry 

out constructive action, and to identify (and prepare applications for) sources of funding. On top 

of it all, once an interest group exists, there is a never-ending flow of requests from public 

bodies for consultation, submissions and participation in hearings on environmental issues. 

The Environmental Legal Assistance Fund administered by the Ministry for the Environment 

helps environmental, community, iwi and hapu groups to prepare, mediate and/or present 

Resource Management Act cases to the Environment Court. 

The Community Organisation Grants Scheme at grantsonline@dia.co.nz (administered by the 

Department of Internal Affairs) helps community groups to provide essential social services, 

including environmental education, to disadvantaged people. salaries and expenses of social 

service workers volunteer expenses project development costs some running costs. COGS made 

grants totalling $236,000 in the 2004 financial year. The Kaiaua Citizens’ and Ratepayers’ 

Association received a COGS grant in October 2004, mainly in support of its community 

information and advocacy services. 

The Lottery Grants Board (www.cdgo.govt.nz/Public/AvailableGrants.aspx) have two options 

for funding of community initiatives that focus on the environment: 

Lottery community makes grants for projects that encourage or enable community selfreliance, 

capacity building and stability, or opportunities for social, civil or cultural participation 

and reducing or overcoming barriers to such participation. 

Lottery Environment and Heritage makes grants for projects that promote, protect and 

conserve New Zealand's natural, physical and cultural heritage. 


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11 Risks, Threats and Current Research 

11.1 Summary of the Issues 

11.1.1 Land use, water quality and sedimentation: 

• Is increasing sedimentation a problem, and can it be better managed? 

• Need for review and integration of the various existing reports on the history of Hauraki 

Catchment sedimentation patterns and the types and quantities of toxins that are 

contained within, plus further appraisal of work that still needs to be done. 

• Is the current regional council management (Environment Waikato) of agricultural 

runoff appropriate/adequate? EW commissioned further research on this in 2004. 

• What are the impacts of effluents from municipal sewage treatment and coastal septic 

tanks? 

• How are the impacts from coastal subdivision, forest harvesting, drainage, roading, etc. 

to be managed (focus on four district councils and two regional councils)? 

• What are the future outlooks for farming, forestry, and mining in the catchment? (Note: 

the decision in 2004 by Thames Coromandel Dictrict Council to open up the possibility 

of further mining in the Coromandel has raised another potential threat to the water 

quality in the Firth and its catchment. 

11.1.2 Coastal vegetation 

• Is the current protection & enhancement of keystone native species adequate? 

• Is the grazing of stock outside the stop bank a problem? 

• Clarification of which introduced species are acceptable/desired (for what purposes) 

• How to effectively achieve eradication/control of undesirable adventive species 

• How do we achieve representative inventories of the vegetation throughout the Ramsar 

Site, and Kopu-Tararu coast? (Note: The only adequate existing information is for 

Kaiaua-Miranda, but EW are planning vegetation mapping of the Firth of Thames in 

2005/2006). 

• What is the heritage value of this mangrove forest? 

• Is the current rate of advancement of coastal mangroves a cause for concern? 

• How important are these mangroves for ecosystem integrity, erosion control, coastal 

protection? 

• How serious are the dieback events, and can or should they be controlled? 

• What are the effects of intertidal channel dredging through mangrove forests? 

11.1.3 Benthic ecology 

• Benthic community is the principal food source for both fish and shore birds, and the 

main determinant of diversity and abundance of the resident and migratory species 


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• What are the causes of the decline in cockle (and possibly other shellfish species) 

populations over the past century (compared to the quantities found in the Chenier 

ridges)? To what extent are key populations fluctuating? Are these the result of natural 

cycles, or are they cause for concern? 

• Need for coordinated research objectives, methodology and collection of data to arrive 

at reliable estimates of species diversity/abundance and better definition of the benthic 

communities. 

• Which are the appropriate indicator organisms for measuring different aspects of 

environmental health in the upper Firth? (Note: EW already use 26 indicator taxa for the 

Regional Estuarine Monitoring Programme). 

• Possible limiting factors 

a) physical factors (contaminants, nutrient enrichment, smothering by sediments, 

salinity & temperature extremes, storm disturbance, grain size, oxygen, 

substrate stability) 

b) biological (predation, competition, food availability, spawning success) 

11.1.4 Fish, fisheries and aquaculture 

• Dependent on high levels of plankton and detritus production in the area 

• How to seriously implement the mandate for ecosystem focus to new fishery research? 

• Need to review the Firth of Thames components of the 1960s to 1990s Hauraki Gulf 

fisheries research, and work with the Ministry of Fisheries to determine what further 

baseline research is needed (particularly with regard to the importance of the Upper 

Firth as a nursery ground for some species) 

• Equitable access to stocks for small-scale commercial & recreational fishers 

• How real is the potential for significant expansion of mussel farming (and possibly cage 

culture) along the Kaiaua-Matingarahi coast), and how might this affect the Firth of 

Thames Ramsar Site? 

11.1.5 Birds 

• What are the factors limiting wader populations in the Firth of Thames? 

• Need for more precise information about relationships between wader bird predators 

and principal benthic invertebrate food species … how to obtain without killing birds? 

a) preferred food species (benthic invertebrates) and annual yields required 

b) baseline invertebrate population estimates (key species), yearly monitoring 

• Concerns about roosting: open coast habitat protection, interaction with coastal grazing 

• Are greater numbers of birds of certain species (especially ducks, herons and 

cormorants) using the rapidly expanding area of coastal mangrove forest? 

• How to manage, inform and engage the increasing numbers of bird watchers? 

• How can work on migratory birds in the Miranda area help to strengthen international 

flyway research, communication, habitat conservation? 


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11.1.6 Enhancement of community participation, recreation and natural 

history education in the area 

• How to encourage more community involvement within the area (other than farming, 

fishing, drainage works and duck hunting), especially through clubs and schools 

• How to attract a “manageable number” of visitors to the area and to increase their 

awareness of its ecological importance and recreational potential? 

• What plans are there for construction of better visitor access to key areas through rights 

of way, car parks, boardwalks, bird hides, interpretive signage? 

• What sorts of community-focused workshops, field trips, teacher training, etc. should be 

offered (expansion of current DoC and EW initiatives)? 

11.1.7 Achieving sustainability of the Ramsar Site in the context of the Firth 

of Thames ecosystem, and protection of ecosystem values, cultural heritage 

and historical features? 

• Are we meeting our obligations under the Treaty of Waitangi? 

• Are we meeting our Ramsar Convention obligations? How is this managed and coordinated 

between agencies? Who should be responsible for what? Is this being 

debated; are any decisions being made? 

• To what extent are the agencies meeting the expectations of the New Zealand 

Biodiversity Strategy? 

• To what extent does the Hauraki Gulf Marine Park Act promote protection? How do 

we engage the Hauraki Gulf Forum in meaningful ways? One idea is that the Forum 

could organise/facilitate a workshop on Ramsar Site and Marine Protected Areas issues 

in the Firth of Thames 

• What are the options for increasing ecosystem protection of the area? 

• How do we control mining of the Chenier Plain and shell banks? 

• How do we effectively recognize and protect aspects of cultural and spiritual 

significance to Iwi? 

• What key historic features require further attention or protection? 

11.1.8 Defining the sorts of actions that may be necessary in response to the 

issues raised in this report and in the November 16 Workshop following the 

report’s release: 

• Further compilation of essential references and relevant existing information 

• Should the Hauraki Gulf Forum facilitate the development of a definitive “big picture” 

research strategy with clear objectives, and an effective regular progress reporting 

mechanism? How to achieve effective co-ordination of such a strategy and the projects 

and the investigators and other stakeholders attached to it? 

• Focus on the National Biodiversity Strategy and ecosystem approach to research: asking 

the right questions about the principal issues (and identifying the gaps in essential 

background knowledge) 


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• Formation of a better picture of Firth of Thames oceanography, especially primary 

productivity patterns/limitations and the dynamics of muddy bottom communities 

• Giving greater impetus to GIS and remote sensing work in Ramsar Site and environs 

• Need for a coordinated effort to uncover the many bits of information from various 

Firth of Thames core sampling (focusing on benthic organisms and sediment structure/ 

content, and new research to complete the picture) 

• How to make the jobs of both statutory bodies and interest/stakeholder groups easier, by 

defining the goals in practical terms, determining who is responsible for what, and 

providing solid scientific background information. 

11.2 Specific concerns about the immediate catchment: 

11.2.1 Silting in 

This is happening, though the rate is still a subject for debate. Is the measurable ‘advance’ of 

mangroves along the Hauraki Plains and Miranda Coast a direct cause of runoff (silt and/or 

nutrients) from the catchment? NIWA and others are researching mangroves elsewhere, and the 

Mangrove Steering Committee is proving to be a strong coordinating force in collating and 

redirecting information as it is gathered from numerous sources. It is now known that 

mangroves play a significant role in trapping silt, especially where they are grouped in dense 

coastal forests. Can we build a picture of the influence of the stop bank on the current 

distribution of mangroves? 

Questions: 

• Is it time for a review of all the data on amounts of sediment entering the Firth via the 

various streams and rivers over time, and doing a new time series to see if the rate of 

sedimentation is changing? 

• Where in the catchment are the main origins of the sediment? 

• What are the types and quantities of the principal nutrients and toxins coming through with 

the sediments from the various origins? 

• Does the sediment contain toxic chemicals and/or heavy metals from agriculture and 

[mainly past] mining operations? EW are commissioning a scoping study to establish 

where in the Waikato Region contaminants from urban and rural runoff are likely to form 

the greatest risk (in terms of the sensitivity of the receiving environment as well), and any 

future monitoring will be based on that study (which will be completed in financial year 

2005). 

• What toxins and heavy metals are currently locked up in normally stable bottom sediments 

(particularly from past gold mining)? What would be the result of a major sedimentstirring 

event like a big storm, tsunami, earthquake (or mining of the Coromandel Harbour 

sediments)? 

• What is the impact of sediment / runoff on the benthic fauna, and therefore on the fish and 

birds in the area? Excess sediment loading is likely to be detrimental to filter feeders. 

According to some locals, the flounder fishery has been affected by loss of sandy substrate 

in the intertidal and subtidal zone (though the 2004-2005 season so far has yielded one of 

the best catch per effort rates ever). 


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11.2.2 Development pressures 

The Kaiaua-Miranda Coast is within commuting distance of Auckland, and residential demand 

is growing. The Thames-Kopu area is experiencing greater demand for residential subdivision 

and light industry. Waitakaruru even has a new subdivision. 

Questions: 

• What are the current provisions in the District Plans for protection of the coastal zone? 

(Note: Seabird Coast Management Area approach in the Proposed Franklin District Rural 

Plan Change – puts potentially stronger zoning constraints on coastal zone development. 

However, the FDC approved in 2004 a major coastal subdivision at Matingarahi that many 

local residents consider to be contravening the proposed Rural Plan Change). 

• How do we determine the human residential carrying capacity on this low-lying coast? 

• What is the impact of the Pacific Coast Highway (particularly the ‘feral campervans’)? 

• Are ‘low impact’ activities such as scenic drives and bird watching really low impact, or 

only when they occur in low numbers, at low frequencies)? 

• What is the impact of septic tanks in porous substrates such as the Miranda-Kaiaua Coast, 

or along the dynamic Thames Coast? 

• What about long-term plans such as the alternative route to Auckland, and the ideas of 

canal housing and/or marina once the Kaiaua Quarry has been exhausted (which may 

happen as early as 2007)? 

11.3 From outside the catchment: 

11.3.1 Import of sediment / nutrients from the wider Hauraki Gulf / 

Auckland. 

• Significant upwelling from the northeast 

• Possible entrainment of Auckland dredging spoils (as of December 2004 there were no 

specific threats) 

11.3.2 Habitat quality of the Auckland harbours and beaches for wader birds 

Questions: 

• How much silt, nutrients, chemicals, heavy metals enter the Firth from the north? 

• How much of the biota migrates into the Firth from the north? 

• Do changes in habitat quality elsewhere impact on the use of the Firth by waders? 

11.4 Uses of the Firth of Thames and Hauraki Gulf 

11.4.1 Commercial and recreational fisheries 

Commercially, there is not too much to worry about, as trawling and seining are prohibited, and 

snapper catches are tightly managed by quotas. Recreational fishing (mainly for snapper) is 

more of an issue, and on-going NIWA studies (contracted by the Ministry of Fisheries) indicate 

a steady increase in the amount of recreational fishing activity in the Firth of Thames. 


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11.4.2 Marine farming 

Mussels and oysters are the only species that have been cultured in this environment, however 

with a plan change finfish and other organisms could also be cultured there. Indeed, the Firth 

offers an ideal habitat and food supply for the greenshell mussel, as well as acceptable 

physical conditions for the farmers to work in. Scallop enhancement has shown some positive 

signs (both for spat collection and for growing on), but there is neither the expanse of water, the 

firm substrate, nor the water quality required for scallops to be grown sustainably (as in the 

South Island’s Tasman and Golden Bays). 

The only foreseeable impact (other than plankton drawdown) from mussel farming between 

Kaiaua and Waimangu Point or at Wilson's Bay (the closest points to the upper Firth where 

marine farming is to be allowed by the two Regional Councils) would be the effects of a major 

northerly storm that could, in an extreme case, tear off droppers and even whole backbone lines 

and buoys and whip them further south in the Firth. 

Questions: 

• Will marine farming have detrimental effects on the biota of the upper Firth by increasing 

detritus levels or decreasing plankton levels in the water, or by creating major increases in 

surface area for the establishment of unwanted invertebrates such as colonial ascidians and 

hydroids? 

• Is there enough flushing action in the lower Firth of Thames to avoid build-up of detritus? 

11.5 Cross-boundary issues 

Questions: 

• Are policies and management strategies consistent between the Waikato and Auckland 

Regional Councils (e.g. Regional Coastal Plans, marine farming development policy, etc)? 

11.6 Global links 

11.6.1 State of the Environment of the wetlands and coastal areas like the 

Firth of Thames Ramsar Site that are part of the East Asian Australasian 

Flyway (Note: the September 2004 preliminary draft of the State of the Hauraki 

Gulf Environment, prepared under the HGMPA, has provided a first step). 

11.6.2 Adventive marine organisms 

There are four species of invertebrates that have shown up on and around Firth of Thames 

mussel farms in significant quantities over the past 3 years. These are either adventive species 

or ones that existed in the past in negligible quantities (and thus not reported in previous 

studies): Chaetopterus polychaete tube worms, Musculista Asian date mussel, Ciona sea squirt 

(tunicate), and predaceous/scavenger flatworms. There was also an unknown prokaryote-like 

organism that contributed to massive die-offs of scallops in 1998-99, and apparently 

unprecedented population explosions of blister worms (or mud worm, a type of polychaete) in 

shellfish at the same time. Cranfield, et al. (1998) report that there are many adventive species 

now in our marine environment, many of them waiting for the right conditions in which to 

multiply. 

Question: 


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• Can we prevent the arrival of adventive marine organisms, given the extent of international 

boat traffic and possible changes in conditions due to global warming? 

11.7 Current Research in the Firth of Thames 

11.7.1 NIWA/EW investigation into sedimentation rates in relation to 

mangrove progradation (start Dec. 2004) 

The rates of sediment inputs to the Firth of Thames and the resulting accumulation rates 

(particularly in relation to the influence of mangroves) has been a topic of much debate in recent 

years, but there has been limited investigation on this to date (see Griffiths and Glasby 1985, 

van Leeuwe 1991, Young and Harvey 1996). Both the sediment inputs from runoff and the rate 

of accumulation in the upper Firth appear to be increasing. 

This study is the first step in increasing the accuracy of predicting sediment accumulation rates 

in the Firth of Thames, and will increase our understanding of the physical processes that drive 

it. One hypothesis is that mangroves are a potential hazard mitigater with respect to climate 

change impacts. It is also important to begin the process of determining the degree of 

ecosystem change being driven by the mangrove progradation/sediment accumulation process 

in the upper Firth (particularly regarding the benthic ecology and its implications for the 

estuarine food chain that is vital to numerous marine and avian predators). 

11.7.2 Coastal Metadatabase (start Jan. 2003) 

The "Coastal Information Database" project was initiated in the 2002/03 financial year, and was 

available in draft form as of the end of 2005. Environment Waikato (EW) holds a large amount 

of information on the physical and biological features of the Waikato Region’s coastal 

environment. This work has been undertaken directly by EW, or contracted out in order to meet 

Council’s environmental monitoring and information gathering requirements. Numerous 

research organizations, such as the University of Waikato (UoW), Department of Conservation 

(DoC) and the National Institute of Water and Atmosphere (NIWA) undertake a range of 

studies that produce information that has the potential to be used more effectively by EW in 

management of the coast. The database will consist of meta-data (data about data) so that the 

existence of all data can be searched. The actual data will need to be sought from the 

organisations that produced it. 

The final form of the completed "database" is not yet decided. Early discussions suggested that 

a map-based tool would be the easiest and most effective way to display and locate the 

information required. Most users of the data agreed that the most common data search was for 

a range of information in an area rather than a Region-wide search for information based on a 

theme or topic. The inclusion of key word information in the metadata sheets (based on a 

consistent list) will still allow data sets relevant to a particular topic to be relatively easily 

extracted. 

11.7.3 Environment Waikato Regional Estuary Monitoring Programme: 

Benthic Macrofauna Communities and Sediment Characteristics (Southern 

Firth of Thames and Raglan Harbour) – Start April 2001 and continuing in 

2005 

This study provides on-going monitoring of the temporal changes in intertidal sediment 

characteristics and benthic macrofauna communities which may occur as a direct or indirect 

consequence of catchment activity and/or estuary development (Turner and Carter 2004). 


137 

Five permanent sites in the upper Firth of Thames (Kaiaua, Miranda, Thames [opposite the Gun 

Club], Kuranui Bay and Te Puru) have been regularly sampled (12 randomly located core 

samples at each site, sampled quarterly or six-monthly). The sediment samples are analysed for 

grain size, total organic carbon, total nitrogen, chlorophyll a, and phaeophytin. 

Changes in the assemblages of monitored benthic macrofauna species/taxa over time have been 

graphed and further examined by multivariate statistical analysis. The consistently common taxa 

found in the upper Firth sediments are polychaetes Aonides oxycephala and Capitellidae, and 

the bivalves Austrovenus stuchburyi, Macomona liliana, Nucula hartvigiana and Paphies 

australis. 

The next report of this project will be submitted in July 2005, and this will include a review of 

the objectives and future directions. 

11.7.4 Department of Conservation 

DoC funded two major investigations of the marine habitats of the Firth of Thames in 2001-02. 

The first of these was a marine reserve investigation by Waikato Conservancy funded through 

the Biodiversity Package - Marine Reserves. Planning for this investigation included a meeting 

of conservancy, regional and head office staff, environmental groups, Iwi and Environment 

Waikato (EW) technical staff at the Miranda Naturalists Trust on 24 May 2001. The area of 

focus extends south from a line between Waiheke Island and Coromandel Harbour to the head 

of the Firth. It reviewed existing information on the biological and physical environment of the 

Firth and the threats to it. A major information gap identified was existing knowledge of the 

subtidal benthic habitats and biological communities present in the area. It was therefore agreed 

that a survey of these habitats should be undertaken as the first stage of the Conservancy’s 

investigation into the Firth. 

The second project involved the development of a national marine environment classification 

(analogous to terrestrial environmental domains). This project was initiated and managed by 

MfE under the Environmental Indicators Project, with technical support from DoC’s Science 

and Research Unit and funding from the Biodiversity Package - Marine Reserves. 

While most of the funding available for the marine environment classification is required for 

development of an EEZ-level classification, there is also a focus on developing a higher 

resolution, regional-level classification. The Hauraki Gulf/Firth of Thames was chosen as one of 

two sites to develop and trial the regional classification. While this area has one of the largest 

collections of biological data sets nationally, their spatial coverages are generally inadequate, 

and a sampling programme providing systematic coverage of the entire area was essential (T. 

Snelder, NIWA, personal communication 2001). The study, which was completed in July, 2002 

(Morrison et al 2002), involved: 

• A large-scale subtidal habitat survey of the Firth of Thames (i.e. the area south of 36 o 

45’S, excluding Tamaki Strait, Waiheke Channel, Coromandel and Manaia Harbours). 

• Initial mapping of benthic habitats using systematically placed digital side-scan sonar 

and QTC View, and using this information to carry out video and grab-sample ground 

truthing to describe the major biological communities associated with each habitat. 

• Priority to identify areas of high benthic biodiversity such as any remaining mussel 

(Perna canaliculus) reefs, horse mussel beds, beds of benthic macroalgae and rocky 

reefs. 


138 

• Identification of the need to establish better co-ordination internally (including 

Auckland Conservancy), with the provider (NIWA) and with the other biodiversity 

agencies (MfE, MFish) and groups undertaking research in the Firth (e.g. EW, tangata 

whenua, EcoQuest, NIWA, University of Auckland, University of Waikato). 

Waikato Conservancy contracted (under Marine Biodiversity Funding) a new Technical Support 

Officer, Marine (Sietse Bouma), in late 2004 to begin work in January 2005 on the 

implementation of some of the findings of the Lundquist et al (2004) and Morrison et al (2002) 

reports, with particular interest in the various significant Firth of Thames Biodiversity issues 

and the threats posed by increasing catchment-derived sedimentation, aquaculture development, 

boating traffic and coastal development. 

11.7.5 Dispersal and Remineralisation of Biodeposits: Ecosystem Impacts of 

Aquaculture (start April 2002) 

This PhD research of Hilke Giles (Waikato University) assesses the impacts of mussel farming 

on sediment nutrient dynamics and the spatial extent of these effects. The main objectives are: 

• To examine the factors regulating the dispersal of biodeposits 

• To investigate the seasonal variation in the flux of biodeposits to the benthos from a 

mussel farm 

• To qualify the impact of biodeposits on the rates of benthic nutrient regeneration 

• To construct models of biodeposit dispersal and sedimentary biogeochemical cycling 

around a mussel farm 

This study will be completed in 2005, and will contribute greatly to the understanding of Firth 

of Thames benthic ecology and some of the more significant impacts on it. 

11.7.6 Summary of other projects currently being undertaken or proposed in 

the Firth: 

• Aerial photography of the Ramsar site – HDC (scheduled for late January 2005) 

• Marine farm environmental assessment and monitoring – EW, ARC, marine farm 

applicants and research organisations 

• Hydrology – EW, NIWA (Including a long-term study of the oceanography of the Firth 

of Thames and how the current patterns, temperature profiles and chlorophyll a 

productivity is influenced by the cyclic phenomena of El Ni o and La Ni a). 

Permanent stations for the monitoring of multiple parameters in place at Coromandel 

and Thames. 

• 25 Harbours Project, inshore trawl surveys – FRST, MFish, NIWA 

• Geology of slumps and delta fans – Willem DeLange, University of Waikato 

• Ecology of intertidal sand flat fauna, including interactions with wading birds – Dianne 

Brunton, Mary Sewell, University of Auckland 

• Management of intertidal shellfish beds – MFish, Hauraki Maori Trust Board 

• Research into the use of traditional knowledge and customary indicators to measure 

changes in biota in the Firth of Thames – Hauraki Maori Trust Board, MFish and MfE 


139 

• Uptake of nutrients by mussel aquaculture – EW, NIWA – estimating the proportion of 

nitrogen and carbon entering the Firth of Thames which is harvested as mussel biomass. 

To be completed before end of June 2005. 

• Impacts of land-use changes on algal dynamics in the inner FoT – EW, NIWA – 

investigating the impacts (in terms of nutrient release to the FoT) of different land-use 

scenarios on algal dynamics for different seasonal scenarios. To be completed before 

end of June 2005. 

• Water quality review – EW - including compilation of results from, and methods used 

in, all known water quality monitoring in the Waikato region, including the Firth of 

Thames. Will lead to recommendations for water quality monitoring programmes in the 

future. 

• Species reference collection currently being prepared at EW from the Regional 

Estuarine Monitoring Programme, which will include complete identification (to 

species level) of all invertebrates sampled at FoT sites. On-going in 2005, expected 

completion toward the end of 2005 (with rare species being added in the future as they 

are found). 

• Vegetation survey in the FoT (Waikato Region part only) – EW – expected completion 

in 2005 / 2006 financial year. 

11.7.7 Auckland University 

Department of Geography, University of Auckland 

Student: Raewyn Railey-Rearic 

Academic Supervisor - Dr Scott Nichol 

Topic: Coastal processes and sediments in the intertidal zone, southern Firth of Thames. 

The primary objective of the study is to document and model the natural processes of sediment 

transport that lead to the formation of shell ridges (Cheniers) along the western shoreline of the 

Firth of Thames. Key mechanisms that are being measured for the study include tidal currents 

(velocity and direction) and wave-induced currents in the intertidal zone. In addition, the spatial 

distribution of surface sediment types is being mapped and sampled using GPS, and detailed 

topographic surveys of bed shape are being conducted. A model describing the transfer of 

sediment alongshore and cross-shore will be produced to account for the concentration of shell 

in ridges. 

11.8 Pertinent Research in Neighbouring Areas 

11.8.1 Mark Morrison, NIWA: Fish in mangroves sampling project Feb 2005. 

Information on utilisation of mangroves by fish is limited for New Zealand’s estuaries. In 

particular we are largely unaware of which juvenile fish may directly utilise mangroves, and 

how this varies across different estuaries, regions and coasts. Our aim is to collect information 

on the role of mangrove stands with different characteristics as fish habitat in New Zealand, and 

use to this information to help underpin more factual debate on estuarine mangrove habitats. 

Most estuaries have been subjected to sedimentation impacts and associated changes in water 

clarity. Based on sampling of other estuarine habitats (channels, seagrass and horse mussel 

beds), we believe that the value of mangroves to juvenile fish will change depending on the 

environment in which the mangroves occur. For instance, in fairly healthy estuaries such as 

Rangaunu and Whangapoua (Coromandel), mangroves are found in relatively clear water 


140 

conditions, often directly adjacent to seagrass beds, and with firm seafloor habitats. In less 

pristine estuaries (such as Tamaki) seagrass beds adjacent to mangroves have disappeared, the 

water is very turbid, and the seafloor composed of deep mud. Fish assemblages are very 

different in these two types of habitats. We suspect that similar patterns will hold for fish in 

mangrove forests. Thus, the value of mangroves to small fishes is likely to be strongly related to 

the general environmental ‘health’ of an estuary. 

We propose undertaking a detailed fish in mangroves sampling project in February 2005 by: 

Sampling along an environmental gradient; ranging from clear waters and firm substrates, 

through to turbid waters and heavy mud substrates and by; sampling along the latitudinal 

decline in mangrove forest heights from north to south. Estuaries that we have identified as 

being suitable to sample within this framework are: 

West Coast – Hokianga, Kaipara (eastern side), Manukau (Weymouth Arm) 

East Coast – Parengarenga, Rangaunu, Mangawhai, Mahurangi, Upper Waitemata, Tamaki, 

Whangapoua (Coromandel), Tauranga (Waikaraka) 

Within an estuary, we propose sampling eight sites down an environmental gradient (generally 

down one estuary arm, where mangroves occur). At each site, we will collect one fyke-net fish 

sample, along with environmental information including water turbidity, dissolved oxygen and 

salinity levels, sediment particle size, mud content, tree height, tree density, and tree trunk size. 

Fish will be sorted to species, counted and measured, and released alive back into the sea where 

possible. 

Across estuaries, we will repeat this approach in a standardised way so that all sampling sites, 

both within and between estuaries, are directly comparable. 

The findings will be publicly available in the form of written reports and papers, so that iwi and 

local communities, regional councils, and other regulatory agencies can use this information for 

improved management of estuarine systems and their associated fish resources. 

Ed. Note: Though this project does not include the Firth of Thames, it is likely that some quite 

strong correlations will be made between the conditions of the upper Firth and what is found in 

similar environments in the study areas. Once the current goals are achieved, a replicate of the 

study could be undertaken in the upper Firth. 

11.8.2 Estimating Recreational Catches of Snapper and Kahawai 

Surveys of recreational boating activity in the Hauraki Gulf have been carried out by NIWA 

(contact Bruce Hartill, Auckland) in 2001-03, with a continuation in 2004-05. Calculations for 

specific Firth of Thames activity have not yet been done. 

Surveys of landings (Recreational Catch Sampling) are being carried out for the Ministry of 

Fisheries by NIWA on snapper (contact Peter Todd, MoF, Nelson) and Kahawai (contact 

Neville Smith, MoF, Wellington). 


141 

12 Firth of Thames Ramsar Site Workshop Report 

Miranda Shorebird Centre, November 16, 2001 

by Marie Buchler 


The purpose of this meeting was to introduce the draft EcoQuest Firth of Thames Ramsar Site 

Report and to discuss with the wider community the issues that have emerged from it. 

Participants were encouraged to consider the development of an action framework for integrated 

management of the Ramsar Site. Emphasis was placed on research initiatives originally 

identified at a workshop held by the Department of Conservation on 24 May 2001 in order to 

better understand how the ecosystem functions. We identified key interest groups, local bodies, 

research units and agencies whose roles are integral to one or more of the issues. The timeframe 

and extent to which resolution of the issue has been addressed in existing strategies and research 

plans were to be noted. 

Contributions from the meeting are grouped as far as possible under the key issues identified by 

the report. Research priorities are addressed within the relevant workshop sessions. Major 

recommendations within each workshop session are underlined. 

12.2 Land use, water quality and sedimentation 

Panel: Sarah Chapman (Chair) (LCC), Steve Clark (HDC), Tony Roxburgh (DoC Waikato), 

Nathan Kennedy (TCDC, Ngati Whanaunga), Marjorie van Roon (AU). Further discussion from 

the floor. 

Is increasing sedimentation a problem and can it be better managed? 

Sediment runoff from the land as a consequence of deforestation and the development of 

agriculture was identified as a primary factor affecting the Firth of Thames ecosystem. 

Management strategies. It was noted that in current practice the management of the littoral 

marine environment is far less stringent than land-based management systems. Most of the 

catchment is dedicated to primary production (principally pastoral farming, some forestry and 

some cropping. Many of the producers working the land distant from the Firth find it difficult to 

appreciate how runoff from their land contributes to problems in the Firth. 

Changed patterns of agricultural land ownership. Many short-term occupants (< 10 years) and 

‘weekend’ farmers may have less concern for stewardship. Because the Hauraki Plains have 

become a ‘food basket for Auckland’, the development of market gardens and other cropping 

activities has precipitated the constructions of more drains, especially in peaty soil. Major 

sediment movement has become a problem in drainage systems like the Maukoro Canal and the 

Karito Canal. 

Steve Clark commented that fourteen years ago sediments were being cleaned from floodgates 

no more than 2-3 kilometres upriver in the Piako. Now they are being cleaned 15 – 18 

kilometres upriver (as far as places like Pataetonga). The physical effects of sedimentation on 

the ecosystem in the Ramsar site were considered more significant than nutrient runoff. 

It was noted, however, that more nutrients are entering the ecosystem than 20 years ago mainly 

through the increased application of chemical fertilisers. 


142 

It was noted that Hauraki Gulf oceanographic research carried out by NIWA over the past seven 

years integrates the effects of both land runoff and offshore nutrient upwelling, though NIWA’s 

principal focus has been on the latter. 

The effects of this region on climate change was raised. The area has rich organic soils and 

sediments going into the estuary through drainage. CO2 is being lost from the soil. In future, 

monitoring of greenhouse gas emissions of different land management practices will need to be 

carried out. 

Is the current regional council management (Environment Waikato) of 

agricultural runoff appropriate/adequate? 

Environment Waikato works with local communities to help farmers understand the need to 

reduce runoff, and encourages fencing waterways and riparian planting through economic 

assistance and advice. 

Riparian Planting Fund: EW has budgeted $10 million over the next ten years has been 

designated. EW are currently considering the allocation of these funds. Criteria apply for the 

selection of sites to be revegetated. 

Educational/advisory initiatives and economic incentives are needed for changing landowners’ 

attitudes toward sediment runoff. Political will is needed to understand the problems caused 

and to implement measures to reduce them. 

Recommendation: The establishment of a total catchment plan (regional). 

What are the impacts of effluents from municipal sewage treatment and 

coastal septic tanks? It was noted that there are ongoing issues about the 

expansion of the Thames municipal facility. 

There is a need to further monitor stream quality. Black sludge had been observed in the 

Whakatiwai Stream, and the question was raised if its origin was illegal discharge from septic 

tanks upstream. Regional Councils can teach, provide testing kits and fund local communities to 

monitor the water quality of their streams. 

How are the impacts from coastal subdivision, forest harvesting, drainage, 

roading, etc to be managed (focus on four district councils and two regional 

councils)? What are the future outlooks for farming, forestry, and mining in 

the catchment? 

Coastal subdivision and short-term land ownership are problems highlighted by tangata whenua. 

Integrated management of consent process. It was noted that TCDC, HDC, EW, and FDC need 

to reach consensus on definitions and about ways of measuring impact and growth in activities 

such as coastal subdivision, forest harvesting, drainage, roading, mining, etc. Following this 

there will be more effective integration of the policymaking and consents process. [See 

recommendation 1.2.2 ] 

Recommendations: 

1) Mapping of shoreline and subtidal substrate profiles. This has particular bearing on the 

seaward extension of mangroves. [NIWA and the Mangrove Steering Group are doing work on 

this] 

2) Investigating the distribution and movement of sediments of different particle size to 

determine where are the areas and magnitudes of sediment buildups (especially relevant with 


143 

regard to substrates that normally host significant populations of benthic invertebrates as lifesustaining 

systems for wader birds and fishes). 

3) Mapping the dispersal of sediment particles coming from different catchments, so that it is 

possible to see where these sediments move. [included in NIWA hydrodynamic modelling?] 

4) Continuing NIWA examination of the effects on the inner Firth of offshore currents and 

upwelling in the outer Hauraki Gulf. 

5) Continuation of mangrove-focused research to determine the effects of siltation on mangrove 

propagule selection of habitat, establishment and development. Do mangroves prefer sediments 

of particular particle size? It was suggested that this is not a primary factor. 

6) Collation and integration of available recorded and anecdotal information to determine where 

mangroves had grown in historical times over different parts of the Ramsar site. Noted that 

coastal mangrove forest had increased since the stopbank was constructed. In the past 38 years, 

they were thought to have advanced 500 metres in places. Increase in sediments in the past 50 

years was noted. Observations during severe storm and floods showed that the mangroves have 

acted as an important flood barrier and protection for the stopbanks. 

7) More focus on research into phytoplankton production in the Firth to ascertain the effects of 

the reduced photic zone in silty waters over the Ramsar site. 

12.3 Coastal Vegetation 

Panel: Bruce Burns (Chair), Bert Laing (Waitakaruru farmer), Leslie Haines (UNITEC), Brian 

Coffey (BTC Associates, EcoQuest), Bill Brownell (EcoQuest) 

Is the current protection and enhancement of keystone native species 

adequate? 

Mangroves: In this workshop session the keystone species considered was the mangrove. Some 

of the issues identified prior to the workshop and listed below were addressed more fully than 

others. 

What is the heritage value of this mangrove forest? And is the current rate of 

advancement of coastal mangroves a cause for concern? 

Mangrove advancement in the Southern Firth of Thames estimated at between 4 and 15 metres 

per year. Is this rate going to `change? At what point does the accretion of mangroves become a 

problem? 

Stella Frances noted that mangrove expansion would cease to be an issue if adequate saltmarsh 

restoration work were undertaken, both in terms of culling mangroves from existing areas of 

saltmarsh, and by enhancing the development of saltmarsh landward of the mangroves 

(particularly where original mangroves are dying out due to rising land levels. 

Are mangroves reducing the diversity of the salt meadows? 

Recommendation: Need for collation of recorded and anecdotal historical information about the 

distribution and abundance of mangroves and the extent of salt marsh “islands” in the 

mangroves. Note: there is a full series of aerial photographs beginning in 1944 and continuing 

every 5-10 years after that. These can be used to describe changes in the Ramsar site. Rick 

Liefting at EW is collating this information (in late 2004) for facilitating comparisons of 

mangrove coverage over the years. 


144 

How important are these mangroves for ecosystem integrity, erosion control, 

and coastal protection? What are the mangroves contributing? 

Mangroves act as a buffer, diminishing the impact of storm driven waves, and they protect the 

stopbanks. Mangroves have facilitated the appearance of islands of other species on the slightly 

higher ground that develops between them (e.g. Coprosma propinqua, Plagianthus divaricatus, 

and Muhlenbeckia complexa). This is somewhat similar to what developed through the 

influence of kahikatea on the flood plain before deforestation and before the stopbank was built. 

Are the expanding mangroves acting as an ecological equivalent of the (previous) kahikatea 

vegetation? 

What is the amount of detritus entering the system and how is this affecting 

the fishery? 

There is a wide range of estimates, but detritus entering the system is probably on the 

increase. 

What ways are the mangroves tying up nutrients in a more refractory form so 

that they become available in a better way for the ecosystem? 

It was noted that vegetative matter becomes trapped between the aerial roots (pneumatophores). 

It is available to grazing invertebrates, or decomposes and contributes nutrients to the 

ecosystem. 

In the most intensely turbid parts of the Firth of Thames (especially at the 

Ramsar site), is plankton productivity significantly reduced, and does this 

influence the productivity of the mangroves? 

Note: Research to date (2001) had not considered this. 

How serious are the dieback events, and can or should they be controlled? 

A major dieback occurred in 1997 on either side of the Waitakaruru Canal, and the effects were 

still in evidence in 2001. Dieback events may be related to upsurge in the mangrove leaf roller 

caterpillar; or the population increases of leaf roller may be a symptom of mangroves that are 

stressed through other factors. 

In the 1997 dieback, those trees that did not recover were bigger trees distant from the creek. 

Those that did recover had foliage below water level that was not subject to caterpillar foraging. 

Regeneration began from lower parts of the plant. It was noted that recovery has been 

widespread and it was felt that dieback was not a major issue. Frost as a stress factor needs 

further study. The shock effect of several –3C to –5C frosts this year (winter, 2001) could have 

precipitated dieback, depending on other ecological conditions. 

What are the effects of intertidal channel dredging through mangrove forests? 

The meeting did not deal with this issue since there were no Hauraki District Council policy 

people present. 

Threatened habitats 

The reduction of salt marsh areas in the Ramsar site and their associated communities was 

identified as a problem. The question was raised if it would be feasible to breach the shell bank 

in certain places around Miranda, in order to bring in tidal waters to be able to re-establish salt 

flats in some coastal areas that have been modified by farming. 


145 

The construction of the stop bank truncated the original sequence (and natural successions) of 

plant communities. It was suggested that perhaps a reserve could be established within the 

Ramsar site for the re-establishment of historic plant communities as determined by the 

Landcare Research environmental domains programme. 

Is the grazing of stock outside the stopbank a problem? 

Control of grazing on what is privately owned land within the Ramsar site requires individual 

negotiation. HDC have been actively seeking agreements with farmers in the Waitakaruru to 

Hot Springs area to control grazing and stock roaming. Stock trampling and stock grazing 

seaward of Kaiaua Road impacts on the salt marsh vegetation. In some areas stock may have a 

role in weed control. There is a need to identify the weed species so that if stock were removed, 

changes could be monitored. 

Recommendation: Clarification of the processes through which an introduced species is 

classified as acceptable, desirable or undesirable needed. Are there any introduced species that 

are acceptable or desired? 

How are undesirable adventive species controlled or eradicated? 

Process DoC: A plant must first be declared a pest, its priority established, a pest management 

strategy described and funding determined. Spartina (Cord Grass), for example, is a species for 

which there is a pest management strategy. It has become a pest through its ability to colonise 

shallow harbours at the expense of native species. 

[Note: The Waikato Regional Pest Management strategy became operative in 2002. Spartina is 

considered to have a major adverse or unintended effect; the benefits are considered to outweigh 

the costs if the conservation values protected (through the eradication of this species) exceed 

$30/ha. Environment Waikato is the lead agency responsible for implementation of the 

strategy, with technical support from DoC. It was also noted that different pest weed policies are 

held by different Regional Councils.] 

Exotic Pampas Grass has been identified as a problem in some parts of the Ramsar site. A good 

example of this is a thick stand of pampas that covers an area around the Whakatiwai Stream 

mouth adjacent to where there is a stand of native vegetation. It was stated that pampas is 

considered a pest species by Environment Waikato, but not by Auckland Regional Council who 

manages the catchment area around Whakatiwai (ARC have since changed this policy, but the 

pampas have not been eliminated due to local differences of opinion). The ARC Pestfacts 47 

(1999) states, “The objective is to prevent its further spread by land activities. Land occupiers 

are encouraged to remove or control this plant growing on their land, but without legal 

obligation.” “Pampas grass is no longer permitted to be sold, propagated, distributed or 

commercially displayed. 

In the EW Pest Management Strategy, the common and purple pampas grass is considered to 

have major adverse or unintended effects but total control region-wide does not meet 

requirements that the benefits outweigh the costs. “Targeted control in parts of the region may 

achieve the objectives at lower cost.” The benefits would outweigh the costs “if conservation 

values protected exceed $850/ha.” The objective/standard of EW is that it is a “‘Containment 

Pest’ with control being discretionary in many areas. The objective is to “prevent the spread of, 

and, where practicable, reduce infestations of pampas in the Waikato Region for the duration of 

the Strategy.” 


146 

How do we achieve representative inventories of the vegetation throughout the Ramsar Site, 

and the Kopu-Tararu coast? (Note: the only adequate existing information is for Kaiaua – 

Miranda.) 

Gathering of historical information about the vegetation 

The valuable historical knowledge about the region and its vegetation was stressed by Lucy 

Tukua (Unitec–tangata whenua). She expressed a willingness to act as an interface between the 

local community and elders. 

The workshop concluded that revegetation of the catchment and the coast are critically 

important. The biggest difference would be made by the establishment of more vegetation on 

private land, particularly along riparian strips. Because the character of the land has changed 

greatly, it may be necessary and useful to establish other species than those that were originally 

there. 

Threatened Species 

Mistletoe (Ileostylus). The few remaining populations at Miranda are growing on salt marsh 

ribbonwood and sparse shrub growth at the edge of the road where they are vulnerable to road 

verge and weed control. DoC is currently trying to restore shrub and scrub vegetation. Host 

species were plants opposite the Shorebird Centre in 2000. Introduction of suitable host plants 

on the reserve land opposite the Wharekawa Marae was suggested. 

Recommendations 

1) That a re-vegetation plan for the entire Ramsar Site and catchment should be established. 

2) That representative inventories of the vegetation throughout the Ramsar Site, and the Kopu- 

Tararu coast, should be compiled, including historical information. 

12.4 Benthic Ecology 

Brian Coffey (Chair) (BTC Associates, EcoQuest), Mark Morrison (NIWA), Rex Smith 

(Waitakaruru fisherman), Ria Brejaart (EcoQuest). 

The benthic community is the principal food source for both fish and 

shorebirds, and the main determinant of diversity and abundance of the 

resident and migratory species. 

Rex Smith noted that flounder caught on the flooding tide have empty stomachs where as when 

caught on the receding tide stomachs are full 

What are the causes of major shifts in shellfish resources here over the past 60 years? To what 

extent are key populations fluctuating? Are these the results of natural cycles, or are they cause 

for concern? There has been a historic mussel dredge fishery and sporadic scallop dredging. 

There is evidence that the extreme sedimentation affects cockle and pipi recruitment and 

growth. 

Which are the appropriate indicator organisms for measuring different aspects of environmental 

health in the upper Firth? Cockles, pipi, mussels, mud crab were suggested. More consultation 

on this issue is necessary. Many questions need to be urgently answered. 

Possible limiting factors are: 


147 

Physical (toxic chemicals, nutrient enrichment, smothering by sediments, salinity and 

temperature extremes, storm disturbance, grain size, oxygen, hydrogen sulphides, substrate 

stability 

Biological (predation, competition, food availability, spawning success) 

Recommendation: There is a need for coordinated research objectives, methodology and 

collection of data to arrive at reliable estimates of species diversity/abundance and definition of 

the benthic food web. Reports on the diversity of benthic organisms vary, and are mainly the 

result of different sampling methods. 

Research questions: 

1) What do the birds eat from the benthic community? 

2) What do fish eat from the benthic community? 

3) How does the benthic community feed or support fish nurseries? 

4) What are the food supplies for the benthic organisms present and where are the origins 

of these? 

5) How can a high quality bird habitat be sustained? 

6) What does the benthic community around and under mangroves consist of? 

7) What effect does mussel farming have on the benthic community under/near it? 

8) Are noxious invasive benthic organisms present? A threat? How can they be managed? 

9) How has the Asian date mussel affected both the benthic organisms and the fish and 

birds that feed on them? 

Asian date mussels need a fairly firm bottom, but still are very thick in some areas sub tidally. 

Doug Pulford noted that the Asian date mussel has changed the fishery, providing a feast for 

snapper and trevally, which have increased in number recently. However it has smothered 

native mussels and crab habitats which supported another species of fish, Ahuru (Auchenoceros 

punctatus), which is no longer present in fishable numbers. 

DoC Waikato Conservancy contracted NIWA to carry out a QTC and sonar sidescan survey in 

the Firth from the Waihou River to Coromandel and Waiheke Island. Further funding from the 

DoC Science and Research Fund was allocated for a northward extension of this survey (see 

Morrison et. al. 2002). 

12.5 Fish, fisheries and aquaculture 

Mark Morrison (Chair) (NIWA), Doug Pulford (Thames fisherman), Rex Smith (Waitakaruru 

fisherman), Clive Monds (ECO), Bill Brownell (EcoQuest). 

Fish, fisheries and aquaculture are dependent on high levels of plankton and 

detritus production in the area 

How can the policy mandate for an ecosystem focus to new fishery research (Fisheries Act, 

1996) be implemented? 

What is the effect of factors such as sedimentation and mangrove advancement on the use of the 

area as a nursery by various fish species? No systematic ecosystem research, and no baseline 

studies were carried out prior to the expansion of the mangroves to determine their role in the 

use of the area by fish as a nursery 


148 

Would there be value in extracting and analysing the Firth of Thames component of the 1970s 

Hauraki Gulf fisheries research? This is not a priority for the current Ministry of Fisheries 

funding round (2001). 

Equitable access to stocks for small-scale commercial and recreational fishers 

The flounder quota for the area between East Cape and Kawhia is 1100 tonnes. The actual catch 

is between 600 –800 tonnes. -Rex Smith. 

Ministry of Fisheries catch records: Every fisherman fills in a catch book that records the size, 

composition and location of the catch. Each area fished is marked on a grid. Fishermen coming 

from other areas are sometimes a problem. 

What does the Ministry of Fisheries do with this information? 

Although under the present system it is not possible to have a localised quota, it was considered 

that localised fisheries management was important. 

Fisheries liaison meetings can be set up under the Act. There are also proposals to establish 

localised fisheries management plans. The Firth of Thames would be a logical area for this. 

An instance was described where a fisherman from another area cleaning nets within the Firth 

introduced a red alga (Manukau Gracilaria) not previously found in the Firth. Complaints had 

been made to the Ministry but no action had been taken. 

Gaps noted in the regulation and enforcement of problems in spite of there being a ‘hotline’ to 

the Ministry. 

It was noted that a lot of small fishermen lease quota (particularly snapper) from companies and 

a lot more people travel round the country with trailer-drawn boats looking for fish to catch. 

Many biosecurity and territorial issues are raised over this. 

Jurisdictions are difficult to define and manage at sea, as the boundaries are usually arbitrary. 

Management of the Firth of Thames open water area should be integrated, and the division 

between EW and ARC removed. 

Taiapure was suggested as a more effective management tool for local control. As described in 

the Fisheries Act 1996, Taiapure has a Maori origin, but applies to any situation where deemed 

appropriate. 

Fluctuations in the abundance commercial fish species 

Information from Rex Smith suggests that there has not been significant fluctuation in flounder 

populations over 25 years, other than short-term changes. 

Flounder only live about three years. Most of the catch comprises 2-3 year olds. There is a 

premium for these bigger, older fish. Flounder are sexually mature before they reach the legal 

catch limit. 

Doug Pulford uses set nets and handlining in the Firth. Set nets are on the bottom or within a 

metre of the bottom. Catch is snapper, flounder, trevally and kahawai. In the 1970’s and early 

80’s there was a problem with snapper stocks but there has been a big increase in the last 2-3 

years – especially in the upper Firth. 

How real is the potential for exponential growth of mussel farming (Kaiaua- 

Matingarahi coast), and how might this affect the Firth of Thames Ramsar 

Site? 


149 

The jurisdictional boundary (between ARC and EW) down the middle of the Firth was raised. 

Environment Waikato made the decision to limit further aquaculture development to prescribed 

areas, and produced a Variation to the Regional Coastal Plan establishing a new development of 

up to 1000 hectares at Wilson’s Bay (to be established in stages). 

The Kaiaua Citizens and Ratepayers wish to persuade ARC to consider applications on the basis 

of a proper policy process. Only one further application (by Thames Mussels) has been publicly 

notified (Note: this was put on hold, along with all other attempts, by the enactment of the 

national Aquaculture Moratorium on November 28, 2001, due to be lifted on December 31, 

2004). Kaiaua Citizens and Ratepayers have written to the ARC to challenge their decision to 

process the application. The developers have stated that their application is for spat catching. 

But it was noted that spat farms easily become mussel farms once the spat settles on the lines 

and begin to be cultured. 

Mussel farms create artificial reefs. Their shadow may attract big predatory fish – stingrays and 

sharks. Hammerhead sharks and big stingrays are quite common in the Firth. 

How frequent were they in the past? Anecdote related that in earlier times scythes were used to 

cut these large fishes out of the nets. 

The debris from the mussel farms might affect the movement of bottom swimming fishes. The 

example was given of flounder that migrate to spawn off Waiheke Island. They do not like to 

travel over a rough bottom. The debris below the mussel lines might create a barrier to their 

natural progression. 

The mussel dredge fishery in the Upper Firth of Thames impacted on stocks of scallops. 

The Upper Firth used to sustain exceptionally strong stocks of mussels and patches of scallops, 

particularly in the middle and on the western side. A very productive mussel dredge fishery 

existed in the Firth from the late 1920s to the mid 1960s. 

Disturbance (from activities like dredging) can cause problems of diseases and the increase of 

adventive and predator species. 

Noted that scallops are not found in the Ramsar site since they don’t like turbid conditions. 

Mussels and oysters do better than scallops in such conditions. Excessive draw down of the 

phytoplankton by filter-feeding bivalves, fallout from the farms and changes in the benthic 

community were considered to be potential problems if mussel farms expand. 

What are the effects of mussel poachers and increasing numbers of recreational fishers 

targeting marine farms? 

Do we expect changes in the composition or abundances of fish populations, or more fish 

coming into such an area? 

It was noted that water temperature played a part in the increase in stocks of snapper. 

12.6 Birds 

David Medway (Chair) (NZOS), David Lawrie (MNT), Adrian Riegen (MNT), Sarah Gibbs 

(Forest and Bird – Northern), Ria Brejaart (EcoQuest). 

What are the factors limiting wader populations in the Firth of Thames? 

Habitat changes (general) 

Birds don’t feel secure in open areas surrounded by vegetation 


150 

Waders need open tidal flats to feed, and open roost sites with good visibility 

Whimbrels and golden plovers have larger flight range. It was thought that these are probably 

not found here anymore because there might not be enough secluded open spots, but the 

suggestion was made that they may be roosting unnoticed in the mangroves during the day. This 

is what has been observed in Asia. 

Loss of roost sites to mangroves – forcing concentration to fewer sites. 

Will mangroves reach out and take over current roost sites north of Miranda stream, possibly 

forcing some species out? 

Habitat Changes in New Zealand 

Predator pressures – stoats in South Island on braided rivers and breeding grounds. Wrybills 

have decreased in abundance in the last few years. There is some evidence to suggest that the 

introduction of RCD virus to control rabbits in the South Island has resulted in the stoats— 

which normally would prey on the rabbits—switching to take wrybill. Stoats have been 

observed crossing the road in the FoT Ramsar site 

Habitat loss in Australasian flyway in East Asia has affected populations of New Zealand 

migrants. 

Examples given of long haul migrant waders such as the godwit and the lesser knot. The godwit 

flies direct to the east coast of Asia, the lesser knot may stop once in the Gulf of Carpentaria. 

Both require good food sources at their Asian stopovers. 

Interspecies relationships 

Noted that the South Island pied oystercatcher population has increased enormously (1965: 600- 

2500; present: 27 000). 

Will the increase of oystercatcher populations force other birds out? – e.g. godwits 

What caused the South Island pied oystercatcher population explosion here? 

Effects of sewerage discharge, parasites and diseases on dense populations. 

How can the effect of interference or disruption on the birds by people be 

managed, and negative effects prevented? 

Low flying aircraft are sometimes a problem. 

Miranda Naturalists Trust has written to CAA. Minimum fly height is 500 feet. MNT would like 

to have a no-fly zone as there is a danger to birds and the planes themselves. 

Supersonic disturbance by air force – disturb mating 

Noted that in the recent applications for the establishment of a spat farm, use of both the water 

column and airspace are included. 

How to manage, inform and engage increasing numbers of bird watchers? 

Noted that the Shorebird Centre plays a significant role in the management of visitors to the 

area. (See Workshop 6) 

Need for more precise information about relationships between wader bird predators and 

principal benthic invertebrate food species. How can this information be obtained without 

killing birds? 


151 

What are the preferred food species of different species. 

Baseline invertebrate population estimates (key species), yearly monitoring needed. 

A map of the distribution of preferred food species needs to be made. 

What are the possible effects on the birds of shellfish diseases? 

What are the consequences of expanding oyster populations in some areas of the shore 

Concerns about roosting: coastal habitat protection, interaction with coastal 

grazing 

Roosts needed within 2-3 kilometres of their open tidal mudflat roost sites. Only two main, 

perhaps a third, high tide shell spits remain where the birds can roost at high tide. These are 

around the stilt pools and at the mouth of the Piako River This is particularly a problem nearer 

the time of migration when the birds are trying to double their body weight. 

Miranda Naturalists Trust were hoping to buy land in order to manage another roost for the 

birds just south of the Shorebird Centre (achieved), 

How can work in the Miranda area help strengthen international flyway 

research, communication, habitat conservation? 

There are only five RAMSAR sites in New Zealand. This is very underrepresented in 

comparison to bird populations and habitats and other nations (160 in UK). 

When a Ramsar site is created, international obligations follow. 

Concern was expressed that only the local (interested) people seem to be working to meet these 

obligations to care for the migratory waders (What about DoC and the various national and 

regional bird protection societies?) 

The Miranda Shorebird Centre is a pivotal link in the international shorebird reserve network. 

(www.miranda-shorebird.org.nz) 

12.7 Enhancement of community participation, recreation and natural 

history education in the area 

Jan Simmons (Chair) (DoC Waikato), Keith Woodley (MNT), Mel Galbraith (UNITECH, 

Auckland Conservation Board), Annie Wilson (Seabird Coast Promotions, Miranda 

orchardist) 

How can more community interest and involvement (other than farming, 

fishing, drainage works and duck-hunting), be encouraged, especially through 

clubs. associations and schools? 

Increased understanding in the community of the significance of the Ramsar site particularly 

with reference to the migratory waders in their national, international and local context is 

needed. How could this be affected? 

Information about the seabird coast and the Ramsar site can be distributed to the businesses in 

the area. 

The sustainable use of the environment, environmentally sound farming options can be 

promoted. 


152 

Some of the beautiful posters at the Shorebird Centre could go in the medical centre, the hotel, 

and the fish and chip shop. Noted that there were people in the community who had never been 

to the Shorebird Centre 

In management of the Seabird Coast a useful link with FDC could be developed. (Note: This 

has evolved significantly since Phillippa Wilson became Chief Executive in 2002, and Raewyn 

Sendles has represented FDC in regular consultations with the Seabird Coast community and 

Environment Waikato during the last half of 2004) 

Noted that Citizens and Ratepayers Association have found the FDC very helpful. 

The way in which the Raglan Community had been involved in sedimentation problems and the 

many issues around marine and coastal ecology was mentioned as a useful model, particularly 

in terms of getting the community involved in local environmental issues and riparian 

revegetation initiatives. The Whaingaroa Environment Community Group has two active 

operating arms: Whaingaroa Harbour Care and Whaingaroa Environment Centre (website: 

www.converge.org.nz/nbio/catchments/whaingaroa Contact: Fiona Edwards, Whaingaroa 

Harbour Care, ph: 07-825 8569 or fionaedwards@internet.co.nz See also: van Roon and 

Knight, 2001. 

The Trees for Survival programme was mentioned. Kits are supplied to schools and there is 

funding available. [Note: the Rotary Club of Pakuranga instigated this programme. It is now the 

responsibility of ARC in this region. Liaison person is Kylie Falconer. ARC field officers 

collect native seed that are then grown to approx. 2.5cm height in nurseries before they are 

distributed to schools who wish to participate in the programme. Schools need to establish a 

‘plant growing unit.’ Steel framed, with shade curtains and benches, and irrigation, it costs 

$3500. Schools are sometimes sponsored to purchase such a unit or they are constructed by 

people in the community. An interested teacher usually carries the growing programme, but 

they are sometimes assisted by a volunteer field officer, who may be a retired person in the 

community, for instance. Children prick out the small seedlings, and transplant them into 

planter bags. When the young trees are sturdy enough to plant out, then ARC will find predator 

free areas where they can be established. Further information is available from ARC.] 

Role of local volunteers 

Landcare Trusts. Where a community group wants to work on a particular issue, Landcare 

provides support. Noted that Landcare are the co-sponsors of the Mystery Creek field-days in 

2002. 

Needs, interest and participation of community groups and organisations: 

All Hauraki Iwi are under the umbrella of the Hauraki Maori Trust Board. [Note: New Ngati 

Paoa Iwi Trust formed as independent body in late 2004] 

Miranda Naturalists’ Trust (Shorebird Centre) 

Seabird Coast Promotions Group 

Kaiaua Citizens and Ratepayers’ Association 

Kaiaua Boating Club 

Kaiaua Beautification Society 

Kaiaua, Waitakaruru, Kopuarahi Schools, Hauraki Plains College 

EcoQuest Education Foundation 


153 

How to attract a “manageable number” of visitors to the area and to increase 

their awareness of its ecological importance and recreational potential? 

An increasing number of visitors to the Shore Bird Centre has been noted over the past ten 

years, due to publicity, and more school day groups and camps: 

• The Shore Bird Centre is often the entry point for visitors to the region and because of 

this there is an opportunity for visitors to be directed on to marked trails that have been 

developed. 

• The Centre has an advocate role for promoting conservation issues. It has a good 

relationship with the DoC Auckland Conservancy. Schools are now making use of the 

Resource kit on Shorebird migration that was produced with DoC funding. 

• It was noted that there is considerable community interest in protecting and enhancing 

the ecology of the area, but that this energy is not being nurtured. Community 

participation is currently minimal, and needs to be facilitated and developed to a much 

greater degree. The logical entity to take the lead in this is the Miranda Naturalists’ 

Trust, with active support solicited from the principal local residents’ groups. There is 

a clear need for serious dialogue among community parties. One important starting 

point is with local iwi, who currently feature only minimally in the MNT sphere, even 

though they played a key role in the opening of the Trust Centre. Their advice and 

participation in activities concerning the conservation of the Ramsar Site needs to be 

actively encouraged. It was also noted that there is a local perception that MNT 

represents Auckland people coming into the Firth and influencing local management, 

with little regard for local concerns. 

What indicators exist to show the impact of visitors? Is there a need for 

baseline studies? Should the impact be monitored? 

NZ Tourism Research Institute website could be useful to visit. 

What plans are there for construction of better visitor access to key areas 

through rights of way, car parks, boardwalks, bird-hides and interpretative 

signage? 

Both DoC and the Shorebird Centre are active in this regard in the area between Miranda and 

Kaiaua, and the TCDC (in collaboration with DoC and EW) is promoting the development of a 

coastal walkway from Tararu to the Kauaeranga, and perhaps eventually to the Waihou. 

The Shorebird Centre sees that it has an important role in explaining the importance of the 

Ramsar site to school pupils and teachers. They are looking at ways funding the buses that bring 

school pupils to Miranda since bus costs reduce school visits. 

12.8 Achieving sustainability of the Ramsar site in the context of the 

Firth of Thames ecosystem, and protection of ecosystem values, 

cultural heritage and historical features 

Panel: Simon Berry (Chair) (Rudd Watts and Stone), Dave West (DoC Waikato), Sarah 

Chapman, David Melville (OSNZ), Bill Brownell (EcoQuest) 

Significance of Ramsar site: perceptions vs. realities Ramsar designation does 

NOT imply regulation/ management of impacts on site through, for example, 


154 

mussel farming or recreational activities. It only provides framework and 

guidelines for integrated management 

Are we meeting our Ramsar Convention mandates at the Firth of Thames Site? 

Panel members consider that we are not meeting the obligations placed upon Ramsar 

signatories. 

Article 3.2 of the Convention concerns the occurrence of change 

There is a need for ongoing monitoring of the site to see what ecological changes are occurring. 

If we could recognize the international importance, not just local importance, this would be an 

accomplishment. 

Ramsar’s principle of “wise-use” encourages management beyond boundaries of the Ramsar 

site. 

Integrated catchment management is very appropriate here. 

“Wise-use” for all wetlands in the country, not just Ramsar sites 

Does the Firth of Thames Ramsar status satisfy Treaty of Waitangi 

requirements? 

To what extent are the agencies meeting the expectations of the New Zealand 

Biodiversity Strategy? Who/What agencies should manage Ramsar site? 

Several stakeholders involved 

Government agencies/organizations control what happens “on the ground,” thus, very important 

to management of site 

Regional Councils: The discrepancies between the regional coastal plans of EW 

and ARC need to be addressed 

Environment Waikato is involved on their “side of the line”. They see their primary issue in the 

area of the Ramsar site as sedimentation runoff and its control through riparian planting. 

ARC plans need revision/reassessment. The meeting recommended that ARC be urged to act in 

line with the HGMPA and the international obligations implied by the Ramsar Convention. 

District Councils: 

Franklin District, Thames Coromandel District, Waikato District, Hauraki District 

DoC: Auckland and Waikato Conservancies 

HGMPA This Act includes mechanism for integrated management. This is the only Act that 

brings all mandates/agencies together 

Treaty of Waitangi—Iwi 

Need consultation. Must and want to participate in action—concerned about the issues 

Fisheries Act 1996 

Ministry of Fisheries – have so far not responded to the invitation to be involved. Challenged by 

the meeting to get involved with the Regional Councils and to a lesser extent the District 

Councils. 


155 

Local involvement 

It was noted that there are obvious benefits of extensive on-going dialogue between community 

partners, possibly through an annual hui that brings locals up-to-date with scientific advances 

and management proposals, and exposes biological interests to local sentiment. Regular 

dialogue among responsible interested parties would facilitate conservation awareness and 

empower locals (and others) to initiate and manage conservation projects. The MNT should be 

pro-active in initiating this dialogue. [Note: Such a process was initiated by Environment 

Waikato in 2004 in the form of two meetings with the community and Franklin District, with 

plans to continue the process in 2005]. 

To what extent does the Hauraki Gulf Marine Park Act promote protection? 

Section 7—concerns sustainability 

Section 8—concerns the management of Hauraki Gulf 

Culture, environment, tangata whenua… 

HGMPA Forum. This was set up to: 

• Integrate management 

• Promote sustainable management 

• Coordinate Efforts - the “let’s talk”/cooperation between stakeholders 

• Prepare lists of issues & monitor progress 

• Report and share information with other jurisdictions: It is vital to the protection and 

management of Ramsar, and representation by regional councils is disappointing 

How do we engage the Hauraki Gulf Forum in meaningful ways? 

The Forum is still a new body. The meeting was reminded that there is a long lag time between 

recommendations made and funding decisions. [Note: See Willis, 2004] 

We need to use the Act. It is pointless if not put to use. Suggestion that a request be made for 

representatives of this workshop to meet with the Forum. 

The Forum needs to be more fully representative of local bodies and Regional Councils 

What are the options for increasing ecosystem protection of the area? 

How do we control mining of the Chenier plain and shellbanks? 

How do we effectively recognize and protect aspects of cultural & spiritual significance to iwi? 

What key historic features require further attention or protection? 

12.9 How to move forward with issues-focussed research requirements 

identified by the EcoQuest report, today’s discussions and the 

May 24 DoC workshop. 

Chair: Margaret Lawton (Landcare) assisted by session discussion leaders. 

Key Issues: 

Further compilation of essential references, relevant existing information, and 

up-to-date summaries of ongoing investigation. 


156 

What scope is there for development of a definitive “big picture” research 

strategy with clear objectives, and an effective regular process reporting 

mechanism? 

How to achieve effective coordination of projects and investigators? 

Focus on Biodiversity Strategy and ecosystem approach to research: asking 

the right questions about the principal issues (and identifying the gaps in 

essential background knowledge) 

Formation of a better picture of Firth of Thames oceanography, especially 

primary productivity patterns/limitations and the dynamics of muddy bottom 

communities 

Giving greater impetus to GIS and remote sensing work in Ramsar site and 

environs 

Need for coordinated effort to uncover the many bits of information from 

various Firth of Thames core sampling exercises, and new research to 

complete the picture 

How to make the jobs of the statutory bodies and interest groups easier, by 

defining the goals in practical terms, and providing solid scientific 

background information 

Research Projects: identification and implementation 

Integration of the large amount of information that has been gathered may be most effectively 

done through Integrated Catchment Research methods leading to Integrated Catchment 

Management plans. How do you decide when you have enough vineyards, farms, marine farms 

in an area? How is this to be determined? In this case you have to consult the local people. 

Methods need to be applied where the results of research can be in a form where it can be used 

effectively. 

The Internet is a good tool here, as it is easy to update information and plans. 

Projects and Approaches 

Sediment research, for example, using aerial photos and remote sensing. These can be the focus 

of ‘Desk-top studies’ of defined areas undertaken by Landcare. 

Tools/databases on soil/climate/are available. Recording the results of remote sensing every five 

years in the National Land Cover database would enable people to see changes in their home 

catchments. 

Constructing food webs of the ecosystem 

Need to link cause and effect so that people distant from the effect can appreciate it 

Need a research plan so people can tack into it. 

Needs a way of integrating information gained into it 

Need to capture historical information 

Need to work in partnerships with other agencies 


157 

Sedimentation: particle size distribution research. Determine whether it has a bearing on the 

selection of habitat by mangroves 

Basic understanding of beach profiles, since this influences the seaward extension of the 

mangroves (NIWA is doing some of this) 

Particle size of materials coming from different catchments to determine where the sediments 

end up (NIWA and EW – hydrodynamic modelling – some has already been done – desk top 

studies. See Stephens, 2003) 

University link useful – offers students a practical research topic 

Vegetation research 

Palynology to learn historical distribution 

Determine relevant revegetation (defining “environmental domains”) 

Mangrove research 

Exposure may be more significant than particle size 

EW are looking at why mangrove coverage is expanding (past research by S. Turner; new 

project under R. Liefting, NIWA contract in 2005) 

Predictions of further mangrove distribution and impacts on the bird populations 

Bird research 

Ascertain whether Ramsar values are being sustained 

OSNZ have offered their records for use by the group (Medway) 

Determine what key bird species and habitats should be protected –identify and understand the 

habitat 

Research the quality of the food the birds are eating (Ref: NIWA research in Auckland Harbour 

on heavy metals and toxins). This is part of the food web analysis. 

Public Awareness 

Raising public awareness of Ramsar generally 

How to involve people who are remote from the effects of environmental problems 

Cultural aspects of the Ramsar site 

Fisheries 

Impact of mussel farming 

Cumulative effects of marine farming and fisheries activities 

Identifying area of the consents process, not ad hoc consents (recent AMA establishment 

process) 

Precautionary Approach 

Water testing (Kathy Walsh) 3 monthly water testing of the fresh water flow into little streams – 

especially in dry years when people take water illegally. 

Need to standardise methodology for monitoring in aquatic environments (Stella Frances). 


158 

Appendix 12.1 Firth of Thames Ramsar Site Workshop Participants 

Surname First Name Affiliation Phone No. Address E-mail 

Aislabie Mark Ambush Marine Farms (09) 232-2641 East Coast Rd., R.D. 3 Pokeno aislb@xtra.co.nz 

Andrews Miria Ngati Paoa (09) 270-6176 23 Gray Ave, Mangere East mandrews@middlemore.co.nz 

Bahler Kris DoC, EcoQuest graduate (09) 299-6064 3 Chantal Place, Papakura kbahler@doc.govt.nz 

Berry Simon Minter, Ellison Rudd & Watts (09) 353-9964 BNZ Tower, 125 Queen St., Auckland simon.berry@ruddwatts.com 

Buchler Marie EcoQuest (09) 232-2552 East Coast Rd., R.D. 3, Pokeno m.buchler@clear.net.nz 

Butcher Jan Forest and Bird (09) 236-9722 P.O. Box 187, Tuakau jjbutcher@ps.gen.nz 

Brejaart Ria EcoQuest (09) 232-2950 25 Pukekereru Lane, RD 3 Pokeno ria@ecoquest.co.nz 

Brownell Bill EcoQuest (09) 232-2550 30 Pukekereru Lane, RD 3 Pokeno bill@ecoquest.co.nz 

Burns Bruce Landcare Research (07) 858-3728 Landcare, Private Bag 3127 Hamilton burnsb@landcare.cri.nz 

Chapman Sarah Lawrence, Cross & Chapman (07) 868-3315 P.O. Box 533, Thames sarahc.lcc@wave.co.nz 

Clark Steve Hauraki District Council (025) 961-726 P.O. Box 17, Paeroa stevenc@hauraki-dc.govt.nz 

Coffey Brian B.Coffey & Assoc., EcoQuest (07) 865-6671 417 Given Ave, Whangamata bricoff@wave.co.nz 

Cummings Tony EcoQuest (09) 232-2501 East Coast Rd., RD 3 Pokeno tony@ecoquest.co.nz 

Frances Stella Dept. of Conservation (09) 232-2550 23 Pukekeru Lane, RD 3 Pokeno stella@ecoquest.co.nz 

Fullam Marilyn DoC Auckland (09) 307-9279 Private Bag 68908, Newton mfullam@doc.govt.nz 

Galbraith Mel UNITEC, Auck. Conservation Bd. (09) 815-4321 62 Holyoake Place, Birkenhead mgalbraith@unitec.ac.nz 

Gibbs Sarah Forest and Bird (09) 303-3079 P.O. Box 106085, Auckland office@ak.forest-bird.org.nz 

Gordon Cherry Forest and Bird (09) 537-1097 115 Levant Place, Bucklands Beach inf4nz@voyager.co.nz 

Haines Leslie UNITEC-Landscape & Plant Sci. (09) 815-4321 Priv.Bag 92025, Mt.Albert lhaines@unitec.ac.nz 

Hodgson Vance Franklin District Council (09)237-1300 Manakau Building, Pukekohe vance_hodgson@franklin.govt.n 

Kennedy Nathan Thames Coromandel DC (07) 868-6025 Private Bag, Thames nathan.kennedy@tcdc.govt.nz 

Laing Bert Waitakaruru Farmer (07) 867-3252 R.D. 6, Thames liz.bet@actrix.co.nz 

Lawrie David Miranda Naturalists' Trust (09) 238-8407 52 Mill Road, RD 2 Pukekohe lawrie@pg.gen.nz 

Lawton Maggie Landcare Research (025) 446-080 198 Dunn Road, Rd 3 Drury lawtonm@landcare.cri.nz 

Litchfield Natasha EcoQuest (09) 232-2501 East Coast Rd., RD 3 Pokeno staff@ecoquest.conz 

Medway David Ornithological Soc. NZ (06) 758-0370 25A Norman Street, New Plymouth dmedway@voyager.co.nz 


159 

Melville David Ornithological Soc. NZ (03) 543-3628 Dovedale, RD 2 Wakefield, Nelson david.melville@xtra.co.nz 

Monds Clive ECO, Snapper & Shellfish W.G. (07) 868-6641 Pakaraka, K Valley RD 2 Thames cmonds@wave.co.nz 

Morrison Mark NIWA Marine Sci., Auckland (09) 375-2050 NIWA, P.O. Box 109695, Newmarket mmorrison@niwa.cri.nz 

Payne Marian Kaiaua Citizens & Ratepayers (09) 232-2991 1845 East Coast Road, RD 3 Pokeno marian.h@zfree 

Pulford Doug Thames Fisherman (07) 868-2882 Springfield Av., Ngarimu Bay, Thames 

Riegen Adrien Miranda Naturalists' Trust (09) 814-9741 231 Forest Hill Rd, Waiatarua (Auklnd) riegen@xtra.co.nz 

Roxburgh Tony DoC Waikato - Area Manager (07) 838-3363 Te Rapa Area Office troxburgh@doc.govt.nz 

Ruzicka Rob EcoQuest (025) 750-993 1718 East Coast Road, Kaiaua rob@ecoquest.co.nz 

Simmons Jan DoC Waikato (07) 838-3363 Private Bag 3072, Hamilton jsimmons@doc.govt.nz 

Smith Rex Waitakaruru Fisherman (07) 867-3359 113 Back Miranda Rd., RD 6 Thames dream.time@xtra.co.nz 

Smith Barb Waitakaruru Farmer (07) 867-3359 113 Back Miranda Rd., RD 6 Thames dream.time@xtra.co.nz 

Stamp Rosalie DoC Auckland (09) 307-9279 Private Bag 68908, Newton rstamp@doc.govt.nz 

Strommer Jae EcoQuest (025) 750-993 1718 East Coast Road, Kaiaua jae@ecoquest.co.nz 

Tukua Lucy UNITEC, Ngati Paoa 18 Eastburn St. Papakura lucy.t@xtra.co.nz 

vanSteenbergen Marina Hauraki District Council (07) 862-8609 P.O. Box 17, Paeroa marina@hauraki-dc.govt.nz 

vanRoon Marjorie Auckland University (09) 373-7999 Planning Dept., Priv.Bag 42019, Aklnd. m.vanroon@auckland.ac.nz 

Vaughan Gillian Miranda Naturalists' Trust (09) 817-9262 103 Huia Road, Titirangi Auckland gillia@pimadelite.co.nz 

Walsh Kathy Kaiaua Citizens & Ratepayers (09) 232-2679 12 Pohutukawa Av., Kaiaua kjwalsh@xtra.co.nz 

West Dave DoC Waikato (07) 838-3363 Private Bag 3072, Hamilton dwest@doc.govt.nz 

Wilson Annie Seabird Coast Promotions (09) 232-7933 Miranda Orchards, RD 1 Pokeno annie_wilson@xtra.co.nz 

Wilton Rosalind Environment Waikato (07) 856-7184 Grey St, Hamilton East rosalind.wilton@ew.govt.nz 

Woodley Keith Miranda Naturalists' Trust (07) 232-2781 East Coast Rd., RD 3 Pokeno shorebird@xtra.co.nz 

Crowley Chris EcoQuest Student (09) 232-2501 255 Marlborough St., Boston MA, USA c_crowley@coloradocollege.edu 

Deimezis Emilia EcoQuest Student (09) 232-2501 51 Halifax St., Boston MA 02130, USA ed47@cornell.edu 

Hollingsworth Spring EcoQuest Student (09) 232-2501 6324 Springmeyer Dr., Cincinatti, OH 

Munro Tom EcoQuest Student (09) 232-2501 1305 W. Clearbrook, Bellingham, WA tommy44boy@hotmail.com 

Timpano Melanie EcoQuest Student (09) 232-2501 255 Evelyn, Pleasant Hill 94523, USA melliegirl12@hotmail.com 

Topping Brian EcoQuest Student (09) 232-2501 734 Fire Ln. Bethlehem PA 18015, USA greentopper@yahoo.com 


160 

13 Conclusions and Recommendations 

by Bill Brownell 

13.1 General Conclusions 

The Firth of Thames Ramsar Site and a large portion of the vast 3600 km 2 Hauraki Gulf 

catchment that surrounds and interacts with it has been totally altered by human activity, 

particularly in the past 130 years. An entirely new ecosystem has been engineered on the 

Hauraki Plains, retaining few of the original swamp/salt marsh habitats and species other than in 

remnant form, except for some of the marine species adapted to brackish water which still have 

the ability to come and go in the rivers and marsh creeks that have not been too severely 

modified. 

There are four features of this nearly 9000 hectare area that make it highly distinctive and 

worthy of special protection in perpetuity: 

• The migratory waders and the intertidal feeding grounds and coastal roosting areas that 

sustain them (particularly, the internationally significant numbers of wrybill, bar-tailed 

godwit, knot and SIPO) 

• The high primary productivity of the waters, leading to robust benthic invertebrate 

communities and pelagic food chain, benefiting a great diversity of fish, shellfish and 

bird species, 

• The Chenier Plain, a unique geological feature that causes coastal land building over 

time through advancing stone/gravel and shell banks, 

• The rapid progradation of the coastal mangrove forest and associated sediment 

deposition, causing the emergence of a new ecosystem that is providing steady habitat 

creation and nutrient supply to an apparently increasing diversity and abundance of 

invertebrate and vertebrate species. 

The physical nature of the Plains has been irrevocably changed. The dominant vegetation types 

of kahikatea, swamp scrub, raupo, flax and others have given way to introduced pasture grasses, 

weeds, shelter belts, forage and food crops. The stopbanks that now define the shoreward 

boundary of the Ramsar Site from the Waihou to the Miranda Stream have put paid to the vast 

flood plain that originally received regular washing by spring and storm-driven tides. 

Those same stopbanks, in tandem with the vast network of canals and drains that service the 

new farmer-controlled Plains ecosystem, have caused a buildup of sediments all around the 

southern coast of the Firth. This is proving to be an ideal medium for the establishment of 

mangroves, which started to spread out in the early 1950s from their historical refuges in the 

mouths of the rivers. Mangroves covered about 1100 hectares of the intertidal area of the upper 

Firth in 2002, and the well-established and dense outer ring of one- and two-year old trees at the 

margins of the 400-900 m wide mangrove fringe appear to account for over 100 hectares more 

of established plants in late 2004. 

The progradation of mangroves is causing the development of a soft bottom (mud) habitat and a 

root system/pneumatophore habitat that is replacing the historical harder-bottom shelly-sandyslightly 

silty environment that still prevails in the intertidal zone of the Miranda-Kaiaua coast 

north of the principal area of mangrove forest. The limited studies available to date (including 

the present chapter 8) indicate a shift in species diversity of intertidal organisms in the upper 


161 

Firth toward a few species that are well adapted to muddy estuaries and/or mangrove roots. 

This could lead to a changing ecology in various aspects, such as the types and abundances of 

avian and marine predators, the changing conditions of habitat (as shelter, feeding and spawning 

grounds, and nurseries for juveniles), and species either repulsed or attracted to the evolving 

situation. 

White faced herons and pied shags are increasing in numbers amongst the mangroves of the 

upper Firth, and we know that flounder and eels are still thriving in this environment, but it is 

not known how the changing near-shore benthic habitat is affecting other fish species. 

Whatever the changes (and the information we begin to acquire about them), the immensely rich 

mudflats and shell banks of the Firth of Thames Ramsar Site have continued to sustain an 

abundance of invertebrate life, especially shellfish, worms, crabs and shrimps. This coastal 

estuarine community thrives on an exceptionally high level of primary productivity dependent 

on recycled nutrients delivered to the system by offshore upwelling, catchment runoff and 

decomposing vegetative matter (now dominated by mangrove leaves). 

The Firth of Thames Ramsar Site is unique: it is not clear just where it fits in our national policy 

and planning structures (and our historical, heritage and biodiversity values) for two main 

reasons: 

1. The extreme modifications that have been made to the vast wetland that originally 

occupied the surrounding land, and the continuing effects of that ecosystem engineering 

on the coastal environment now covered by the Ramsar Site, 

2. The complexity of overlapping statutory management structures and ownership/ 

custodianship issues. 

The Ramsar Site is composed of two largely overlapping intertidal communities: 

1. the classic sand/shell/silt habitat hosting a diversity and abundance of invertebrate fauna 

that attracts great numbers of feeding shorebirds and fish, 

2. the opportunistic coastal mangrove community that is steadily moving out onto the 

mudflats, aided by the dynamic sedimentation process occurring along the southern and 

south-western coasts of the Firth (with limited, but perhaps increasing, biodiversity). 

The mangroves are a “buffer”, protecting the land from erosion by the sea, and absorbing, 

redistributing and/or digesting a portion of the nutrients, sediments and toxic chemicals 

delivered by the runoff that courses through it. 

In its entirety, the Ramsar Site provides a balance among three major forces: economic 

(agriculture, fisheries, marine farming, forestry, mining and tourism), cultural (underscoring the 

importance of the relationship between people and the environment, in a tradition-based, but 

modern context), and the recognised need to protect New Zealand’s natural areas and 

biodiversity, even when they have been altered. 

The international ecological importance of the Firth of Thames Ramsar Site has been clearly 

established, and recognised by the government of New Zealand. Due to the vast ecological and 

land use changes that have occurred in and around it, the complexity of cross-boundary 

management issues and a vague national policy concerning it, there needs to be a clearer 

framework for managing it locally and nationally. This should preferably happen in an 

integrated manner, under the coordination of one body (such as the Department of 

Conservation, Waikato Regional Council or an empowered Hauraki Gulf Forum-like entity) 

with a clear mandate, a practical working plan, and adequate resources for maintenance and 


162 

development. All of the stakeholders and responsible concerned parties must be fairly 

represented in the planning and decision-making process. 

Nomination of the Firth of Thames Ramsar Site for inclusion on the New Zealand Tentative List 

for World Heritage Site designation would be a strong step beyond the Ramsar status in terms 

of gaining significant recognition of the natural and cultural values of the coastal marine area of 

the Firth of Thames. Even if the actual designation didn’t come through for a few years, a first 

step would provide the necessary encouragement for regional and national government to 

tighten the legal status of the present Ramsar Site in the New Zealand context. 

Current policy and planning structures at both national and local level are limited not so much 

by a lack of vision as by the scarcity of knowledge of the physical, chemical and biological 

processes at work in this highly dynamic ecosystem. There needs to be a re-focusing of 

research, with the express purpose of using solid and integrated scientific analysis to establish 

what is physically happening (particularly with regard to sedimentation), what is ecologically 

significant, and how the two can best be managed through improved policy and planning tools 

to fairly serve the cultural, economic and conservation interests involved. 

Our knowledge of the marine resources of the area is fragmented, and what little we know 

comes from the traditional individual species approach to fisheries research. This had led to a 

poorly defined marine policy that deals only with stocks of commercially significant species of 

fish that happen to pass through the area. Marine policy and management in the entire Hauraki 

Gulf needs to be based on an ecosystem approach, and all of the isolated marine research 

initiatives need to be integrated. 

Scallops and mussels both were abundant on the more stable substrates in the past, but the 

combination of past over-fishing and the heavy build-up of sediments in recent history have led 

to severe reductions in the populations of these two species. Favourable habitat for the highly 

successful cockles is much less extensive now than in the past. There have been no studies to 

quantify what is happening with these three keystone species. 

Integration is clearly mandated in the enabling legislation of the Hauraki Gulf Marine Park Act, 

which the Auditor General (2001) recognizes as a key element in fulfilling our international 

obligations regarding Ramsar. This Act provides a policy framework that could precipitate an 

effective coordination among the many government entities, iwi and other stakeholders, to focus 

on an understanding of this ecosystem through the interrelationships of its many components, 

and a full appraisal of its strategic importance to the entire Hauraki Gulf (catchment included). 

At the end of 2004, nearly five years into the HGMPA, very little has been achieved. The most 

significant progress of all has been the submission, in September 2004, of the Hauraki Gulf 

Forum Performance Review and the State of the Environment Report. Both of these documents 

have the potential to precipitate more sustainable environmental management for the wider 

Hauraki Gulf ecosystem, but they could also die a slow death on the shelf if the political will 

does not materialise. 

It is imperative to develop an integrated management plan for the entire Hauraki Catchment and 

associated marine areas, including the Ramsar Site. Such a plan would recognise the ecosystem 

changes that have occurred, particularly over the past 160 years, and provide for solid scientific 

research that would document the evolution of the changes. It would also give definition to the 

management and policy tools that will be needed for assuring sustainability in the face of all the 

pressures for recreational and commercial use of this environment. 


163 

A clear, consistent definition of the term “Coastal Environment” as it applies to management 

responsibilities of Regional and District Councils should be adopted. While the NZCPS and 

regional coastal plans indicate that the Coastal Environment includes the CMA, there is a varied 

interpretation of what other landward features or areas are included in the Coastal Environment. 

Inland activities can have a very significant impact on coastal morphology and water quality 

through nutrient transport in ground water and sediment transport in surface water. 

Much of the day-to-day management of the Ramsar area is actually done by the local farmers 

and fishers in terms of their grazing and harvesting practices. This has worked reasonably well 

under present regimes of relatively low use, but future policy and management will need to take 

into account the continuing concerns about drainage and flood control problems on the Miranda 

and Hauraki Plains, and the growth that is happening all around the Firth of Thames. 

13.2 Recommendations 

• The new policy initiative by the Department of Conservation (in the 3 months from 

Jan. to Mar. 2005) to identify potential World Heritage Sites in New Zealand provides 

an opportunity to formulate a proposal for the Firth of Thames Ramsar Site to be 

included. This could satisfy the urgent need for protection, research and education of 

this vital and unique ecosystem, particularly the intertidal and coastal habitats and the 

migratory waders and marine species that use them. It is especially necessary to have 

such a high level of protection in terms of priority funding for research into the major 

ecosystem changes that are occurring in the upper Firth, and the ever increasing human 

impacts. 

• An integrated research programme including the whole Firth of Thames marine, 

estuarine and coastal environment. The objective is to effectively track the changes that 

are occurring to the flora and fauna in this vital ecosystem as a result of global 

warming, fishing practices, coastal development, agriculture, forestry, marine farming, 

the El Ni o phenomenon, habitat destruction and other environmental impacts … and 

then to effectively apply the appropriate policies and resource management tools in the 

interest of achieving sustainability. This project could be used as a model for NIWA 

and Landcare and other applied research institutions to develop integrated approaches to 

the broader environmental issues. 

• There is a pressing need for an ecosystem approach to fisheries research throughout the 

territorial seas of New Zealand. The scallop fishery and mussel farming could prove to 

be appropriate test cases in the Hauraki Gulf, with all of their associated resource use 

and species competition issues. 

• Much more information is needed about both the historic and the current sedimentation 

patterns, composition, volumes over time, rates of retention (accretion), contributions to 

the wider Hauraki Gulf, and effects on key organisms. This is the most pertinent global 

question facing the Firth of Thames Ramsar Site and the whole Hauraki Gulf 

ecosystem, and should be a focal point of research in the immediate future. 

• Consider the coastal lagoons used for roosting at Miranda, and the possibility that 

mangroves will eventually take over this habitat. It may prove to be necessary to 

control small quantities of lagoon-fringing mangroves in order to keep these crucial 

habitats open. 


164 

• Undertake a comprehensive study of the Ramsar Site coastal mangrove forest, which 

now covers over 1100 hectares, and appears to be expanding at an accelerated rate 

(adding greater coverage and detail to the joint EW/NIWA project currently underway). 

Ask the key questions: what is the true rate of expansion (and what forces control it), 

what are the natural controls (such as dieback, storms and frost), and what are the 

ecosystem implications in terms of benthic fauna, terrestrial fauna, coastal accretion and 

bird habitat? 

• Do a repeat in the Firth of Thames (with any indicated refinements) of Morrison’s 2005 

study of fishes in coastal mangrove ecosystems. 

• Investigate the feasibility of establishing a prototype coastal salt water impoundment for 

the culture of mullet (as a possible alternative land use to the current low value grazing 

by livestock). 

• Establish walkways, hides and all-weather interpretation panels at strategic points 

around the Ramsar Site. 

• As the number of visitors grows (with their desire to get as close as possible to the birds 

…a desire shared by the cats and dogs that some bring with them), so grows the need 

for an effective long-term people management plan for the whole Ramsar Site (and 

particularly the main bird roosting area between Kaiaua and the Miranda Stream). 

• Build on the combined momentum of this project, the informal but effective 

consultation group of EW, DoC, FDC, Iwi and community, and the presence of three 

broad-based and proactive education/advocacy organisations in the Kaiaua/Miranda 

community (Kaiaua Citizens’ & Ratepayers’ Association, EcoQuest and Miranda 

Naturalists’ Trust) to develop a 5-year management plan for the Ramsar Site and the 

coastal lands around it. This would include the proposed strategic approach to visitor 

facilities and services (see section 10.2.6). 

• Continue to keep a close watch (and involvement in the decision making with the two 

regional councils) with regard to proposed aquaculture development in the Firth (and its 

many potential ramifications for this vital ecosystem). 

• Carry out a Customary Indicators project (with the Paoa-Whanaunga Marae taking the 

lead) to document the early history and cultural and resource use practices of tangata 

whenua on the western shore of the Firth (see Hauraki Maori Trust Board 1999). 

• Establish an environment centre for the upper Firth of Thames at Kaiaua or Miranda, 

and eventually a branch at Kopu or Thames, to educate the public about the 

environmental issues of the coastal marine area and to establish effective advocacy for 

sustainable management through close liaison with national and regional agencies, 

territorial authorities and resource user entities. 


165 

14 Bibliography 

By Marie Buchler, Ria Brejaart and Nigel Keeley 

[A key to institutional and personal abbreviations used in the location of documents follows 

bibliographic entries] 

Agget, J. & Simpson, J.D. (1986). Copper, chromium, and lead in Manukau Harbour sediments. 

New Zealand Journal of Marine and Freshwater Research 20, 661-663. 

Subject: Heavy metals in estuarine sediments 

Keywords: sedimentation, heavy metals 

Copy held: University of Waikato 

Allan, H.H. (1982). Flora of New Zealand: Volume I. Wellington, New Zealand: Government 

Printer. 

Subject: Vegetation 

Keywords: plant taxonomy 

Copy held: EQ 

Anderson, F.E. & Meyer, M.M. (1986). The interaction of tidal currents on a disturbed 

intertidal bottom with resulting change in particulate matter quantity, texture and food 

quality. Estuarine, Ocean and Shelf Science 22, 19-29 

Subject: Benthic ecology, oceanography 

Keywords: benthic fauna, scallops. 

Copy held: EQ (NK) 

Anderson, M.G. (2003). Investigations into shorebird community ecology: 

interrelations between morphology, behaviour, habitat and abiotic factors. 

Unpublished master’s dissertation, University of Auckland, Auckland, NZ. 

Keywords: foraging methods, lesser knot, bar-tailed godwit, pied oystercatcher, wrybill, 

tidal effects, abiotic factors, metabolism, weight gain, bill length. 

Anutha, K. & O’Sullivan, D. (Eds.). (1994). Aquaculture and coastal zone management in 

Australia and New Zealand: a new framework for resource allocation. Launceston, 

Tasmania: Turtle Press. 

Subject: Marine farming 

Copy held: University of Waikato SH131.A72 1994 (NZ Collection) 

Ashby, G. (1985). Geological controls on landsliding in the Kauaeranga Valley, Coromandel 

Ranges, and sources of sediment in stream channels. Unpublished master’s dissertation, 

University of Waikato, Hamilton, New Zealand. 

Subject: Geology 

Copy held: University of Waikato, QE599.N45A84 1985 

Ashby, H. (1964). The history and legends of the western coast of the Hauraki Gulf: from 

Kawakawa Bay to Kaiaua, centred mostly around Orere. New Zealand: Franklin Times 

Print. 

Subject: History 

Keywords: Firth of Thames, Hauraki Gulf, human history 

Copy held: University of Waikato DU436.A82A823 1963 (NZ Collection). EQ (BB) 


166 

Auckland Acclimatisation Society. (1986). Fisheries information and wildlife values of 

tributaries of the Waihou River and selected streams of the western Coromandel. [s.1]. 

New Zealand: Auckland Acclimatisation Society. 

Subject: Fish, birds 

Copy held: University of Auckland, NZ 

Auckland Regional Authority. (1987a). Landforms of the Firth of Thames: 1. The Chenier 

plain at Miranda. Planning Department, Auckland Regional Authority, Auckland, NZ. 


Auckland Regional Authority. (1987b). Landforms of the Firth of Thames: 2. Gravel Ridges 

at Whakatiwai. Planning Department, Auckland Regional Authority. 


Auckland Regional Council. (1999). Proposed Auckland Regional Plan: Coastal 

(Note: Final version delayed due to new aquaculture variation and stormwater issues – due to 

become operational in 2005) 

Subject: Policy and planning 

Keywords: marine farming, natural character, habitat, coastal processes, water quality, 

foreshore, seabed, natural hazards, public access, cross-boundary management, monitoring 

Copy held: EQ 

Auditor General of New Zealand. (April 2001). Meeting international environmental 

obligations.Part 3: The Ramsar Convention on Wetlands of International Importance. 

Wellington, NZ: Report of the Controller and Auditor General. 


Keywords: establishing a framework, obligations, agencies responsible, obstacles to 

implementation, reporting to Parliament. 

Copy held: EQ (BB) 

Augustinus, P.G.E.F. (1989). Chenier and Chenier plains: A general introduction. Marine 

Geology 90, 219-229. 


Bacon, M.R., & Bradbourne, A. (1976). The inner Hauraki Gulf: A resource study. Auckland, 

New Zealand: Auckland Regional Authority, Planning Division.115pp. 


Copy held: ARC 

Bacon, M. R. (1975). The coastal ecology of a recreational resource area: Kawakawa Bay to 

Miranda. 2 nd edition. Special Report to the Auckland Regional Authority: Department 

of Education, Wellington, NZ. 

Subject: Birds, Benthic ecology 

Keywords: Firth of Thames, intertidal ecology, invertebrates, shellfish, zonation of coastal zone 

flora and fauna, Kaiaua Point, Kaiaua Stream, distribution and abundance of birds, roosting 

areas, shore profiles, sediments, siltation 

Copy held: EQ, Auckland University 

Barrier, R.F.G. (1994). Biological resources of the Waihou River. Hamilton, New Zealand: 

Environment Waikato #9982. 

Focuses on Waihou and tributaries downstream of Te Aroha. Covers a large area of catchment, 

including in-river values and species. 

Subject: Benthic ecology 


167 

Keywords: Waihou and tributaries, biological, resources. 

Copy held: Environment Waikato 

Barter, M. (2002). Shorebirds of the Yellow Sea: Importance, threats and conservation status. 

Wetlands International Global Series 9, International Wader Studies 12. Wetlands 

International – Oceania, GPO Box 787, Canberra. 

Copy held: Miranda Shorebird Centre 

Bartrom, A.A. (1989). The Coromandel scallop enhancement project 1987 to 

1989.Unpublished report of the joint programme between the Overseas Fishery 

Cooperation Foundation of Japan and the Ministry of Agriculture and Fisheries, New 

Zealand. Auckland: MAF Fisheries North. 

Subject: Marine farming, shellfish 

Keywords: scallop and mussel spat, settlement and growth rates, Firth of Thames, survival, 

fouling, serial spawning, spat collection, and release 

Copy held: EQ 

Bartrum, J.A. (1926). The west of the Firth of Thames. Transactions of the New Zealand 

Institute 57, 245-253. 


Keywords: geology, sedimentology, Miranda fault. 

Copy held: EQ 

Battley, P. F. (1996). Ecology of migrant shorebirds in New Zealand, focusing on 

Farewell Spit, North-West Nelson. Unpublished master’s dissertation, Massey 

University, Palmerston North, New Zealand. 

Battley, P.F., Melville, D.S., Schuckard, R., & Balance, P.F. (2004). Quantitative 

survey of the intertidal benthos of Farewell Spit, Golden Bay. Ministry of 

Fisheries Biodiversity Fund Contract ZBD2002-18, Wellington, NZ. 

Baylis, G.T.S. (1935). Some observations on Avicennia officinalis L. in New Zealand. 

Unpublished master’s dissertation, University of Auckland, New Zealand. 


Beaglehole, J.C. (Ed.). (1963). The Endeavour Journal of Joseph Banks 1768-1771: Volumes 1 

& 2. NSW, Australia: Public Library of New South Wales/ Angus and Robertson Ltd. 


Keywords: Waihou River, mangroves, kahikatea, flax, Maori settlement. 

Copy held: EQ 

Beaglehole, J.C. (Ed.). (1968). The Journals of Captain James Cook on his voyages of 

discovery. The Voyage of the Endeavour 1768-1771. UK: Cambridge University Press. 


Keywords: Waihou River, mangroves, kahikatea, flax, Maori settlement. 

Copy held: EQ (part only) 

Bisset, B. (2000). Catch that spat. Vision Hauraki Gulf Newsletter 18, 7. 

Subject: Marine Farming 

Keywords: spat collection, plankton bloom 

Copy held: EQ 


168 

Black, K.P., Bell, R.G., Oldman, J.W., Carter, G.S., & Hume, T.M. (2000). Features of 3dimensional 

baratropic and baroclinic circulation in the Hauraki Gulf, New Zealand. 

New Zealand Journal of Marine & Freshwater Research 34, 1-28. 

Subject: Oceanography 

Keywords: north-east shelf, upwelling, tidal currents, internal tide, winds, oceanography 


Blackwell, R.G. (1984). Aspects of population dynamics of Austrovenus stutchburyi in Ohiwa 

Harbour. Unpublished master’s dissertation, University of Auckland, New Zealand. 


Keywords: Austrovenus stutchburyi, cockle, benthic fauna, estuaries 

Copy held: Auckland University, EQ (NK) 

Blomert, A.M. (1996). Oystercatchers and their estuarine food supplies. Zeist, Netherlands: 

Netherlands’ Ornithological Union. 

Subject: Birds 

Copy held: University of Waikato QL671.A67 v.84A. Hamilton, New Zealand. 

Booth, W.E. & Sondergaard, M. (1989). Picophytoplankton in the Hauraki Gulf, New Zealand. 

New Zealand Journal of Marine & Freshwater Research 23, 69-78. 


Keywords: marine picophytoplankton, plankton, Hauraki Gulf, qualitative data, quantitative. 

Copy held: EQ 

Bowling, F.M. (1989). Volcanic geology of ignimbrites on the western margin of the Hauraki 

Depression in the Mangatangi Area. Unpublished master’s dissertation, University of 

Waikato, Hamilton, New Zealand. 


Copy held: University of Waikato QE462.I35B68 1989 

Bowman, M.J., & Chiswell, S.M. (1982). Numerical tidal simulations within the Hauraki Gulf, 

New Zealand. In: Nihoul, J.C.J. (Ed). Hydrodynamics of semi-enclosed seas (pp.349- 

384). Amsterdam, The Netherlands: Elsevier. 


Bradshaw, B.E. (1991). Nearshore and inner shelf sedimentation on the East Coromandel 

coast, New Zealand. Unpublished doctoral dissertation, University of Waikato, 

Hamilton, New Zealand. 

Subject: Sedimentation 

Brandon, A., & Collins, L. (2004). Plant Conservation Strategy Waikato Conservancy. 

Department of Conservation. 

Brodie, J.W. (1960). Coastal surface currents around New Zealand. New Zealand Journal of 

Geology and Geophysics 3, 235-252. 


Keywords: oceanography, surface currents 

Broekhuizen, N., Ren, J., Zeldis, J., & Stephens, S. (2003). Ecological sustainability 

assessment for Firth of Thames shellfish aquaculture: Tasks 2-4 – Biological 

Modelling. NIWA Client Report: HAM2003-120, December 2003. 


169 

Copy held and available from the clients: Western Firth Consortium; Auckland Regional 

Council; Environment Waikato). 

Brown, D.A. (1942). Geology of the West Coast of the Firth of Thames. Transactions and 

Proceedings of the Royal Society of New Zealand. 72,69-84. 


Keywords: sedimentation 

Bryce, A. (1998). The chemistry of shallow groundwaters at Miranda, Firth of Thames. 

Unpublished master’s dissertation, University of Waikato, Hamilton, New Zealand. 

Subject: Hydrology 

Keywords: cations, anions, nutrients, shallow groundwater, seawater, nitrate, phosphate, sulfate, 

fertiliser runoff, leaching of animal wastes, stock numbers. 

Copy held: EQ 

Buchanan, S. (1994). The settlement behaviour and recruitment of Perna canaliculus. 

Unpublished master’s dissertation, University of Auckland, Auckland, New Zealand. 

Subject: Shellfish 

Keywords: marine farming, migration 

Copy held: EQ 

Bulloch, B.T. (1974). Land use recommendations based on vegetation assessment for two 

stands of indigenous bush, Findlays Road, Miranda. Department of Biological 

Sciences, University of Waikato, Hamilton, New Zealand. 

Subject: Land use 

Keywords: land use in the catchment, botany, ecology 

Copy held: University of Waikato QH1U58 no.2. (NZ collection, outsize) 

Burns, B.R. (1982). Population biology of Avicennia marina var. resinifera. Unpublished 

master’s dissertation, University of Auckland, Auckland, New Zealand. 

Subject: Mangroves 

Keywords: mangrove, population biology 

Copy held: EQ 

Burns, B.R. (June 1998). Mangrove dieback at Waitakaruru. Waikato Botanical Society 

Newsletter. 

Subject: Mangroves. Brief note on possible causes of defoliation and dieback of mangroves at 

the Waitakaruru River mouth in December 1997. It is suggested that an outbreak of the 

mangrove leaf-roller (Planotortrix avicenniae) - a moth endemic to the New Zealand 

mangroves - was the cause of the observed dieback. 

Keywords: Avicennia marina, dieback, defoliation, mangrove leaf-roller (Planotortrix 

avicenniae), Firth of Thames. 

Copy held: EQ 

Burns, B.R. (2003). Comments on “LaBonte, A.W., LaBonte, R.R., Farnsworth, M.C. 2003: 

The New Zealand Mangrove: monoculture vs. mangal” Unpublished paper, Landcare 

Research, Hamilton 

Burns, B.R.& Ogden, J. (1985). The demography of temperate mangrove [Avicennia marina 

(Forsk.) Vierh.] at its southern limit in New Zealand. Australian Journal of Ecology 

10:125-33. 


170 

Subject: Mangroves. The Ohiwa harbour population of Avicennia marina var. resinifera has 

been increasing significantly since about 1905. Similar expanding populations are found 

elsewhere in the southern part of Tauranga Harbour and in the Firth of Thames. The Ohiwa 

population was analysed using a Leslie matrix model. The modelling indicated that 

survivorship of the young tree size classes is the main determinant of the population growth 

rate, while annual seed production was relatively unimportant 

Keywords: vegetation, Leslie matrix, population modelling 

Copy held: EQ 

Burns, N.M., Hume, T.M., Roper, D.S., & Smith, R.K. (1990). Climatic change: Impacts on 

New Zealand estuaries. Wellington, NZ: Ministry for the Environment. Pp. 81-84. 


Keywords: general ecology, climate change, estuaries, global warming, sea level rise. 

Copy held: EQ 

Cameron, E.K. (2000). An update of the distribution and discovery of Ileostylus micranthus in 

the Auckland Region. Auckland Botanical Society Journal 55(1), 39-44. 

Subject: Plants 

Keywords: mistletoe hosts, green mistletoe, Podocarpus totara, Coprosma propinqua, roadside 

activity, Kaiaua-Miranda 

Copy held: EQ, Department of Conservation, Auckland 

Carter, D. A. (1981). Preliminary baseline water quality (Waihou and Ohinemuri rivers): 

Interim report. Hauraki Catchment Board. Report no. 108. 


Keywords: water quality, Waihou, Ohinemuri, Hauraki, inputs, discharges. 


Carter, L., & Heath, R.A. (1975). Role of mean circulation, tides and waves in the transport of 

bottom sediment on the New Zealand continental shelf. New Zealand Journal of 

Marine and Freshwater Research 9, 423-448. 


Keywords: water circulation, tides, waves, currents 

Carter, L., & Eade, J.V. (1980). Hauraki Sediments. NZ Oceanographic Institute Coastal Chart 

Series 1:200 000. Wellington, NZ. 


Chapman, V.J., & Ronaldson, J.W. (1958). The mangrove and salt marsh flats of the Auckland 

isthmus. DSIR Bulletin 125. Wellington, NZ: Government Printer. 


Keywords: mangrove, Avicennia marina 

Churchman, G.J., Hunt, J.L., Glasby, G.P., Renner, R.M., & Griffiths, G.A. (1988). Input of 

river-derived sediment to the New Zealand continental shelf. II: Mineralogy 

composition. Estuarine, Coastal and Shelf Science 27, 397-411. 


Keywords: river discharges, sediment sources, continental shelf, chemical composition, clay 

mineralogy 

Copy held: EQ 

Cochrane, G.R. (1981). Landsat images of New Zealand. Christchurch, New Zealand: Action 

Publications. 


171 


Keywords: Landsat, remote sensing 

Cody, R. (1999). Observations of wader distribution in a tidal mangrove salt marsh, Miranda, 

NewZealand. Unpublished Independent Research Project, EcoQuest Education 

Foundation, Kaiaua, New Zealand. 


Keywords: Chenier plain, tidal mangrove salt marsh, Sarcocornia, channel margin zone, 

Charadriiformes, wader ecology, habitat preferences 

Coffey, B.T. (1994a). Commentary on a proposed shellfish monitoring programme, Coastal 

Marine Area: Waikato Region. Brian T.Coffey & Associates, Hamilton. MRD 

/Shellfish /01 Environment Waikato, February 1994. 


Keywords: Environmental management, mussel, monitoring, shellfish, heavy metals, 

bioaccumulation 

Copy held: EQ 

Coffey, B.T. (1994b). Shellfish monitoring programme, Coastal Marine Area - Waikato Region. 

Brian T. Coffey & Associates, Hamilton. CMRD / Shellfish / 01 Environment Waikato, 

February, 1994. 

Subject: Marine Farming 

Copy held: Brian T. Coffey & Associates; Environment Waikato 

Coffey, B.T. (1995). Coromandel Mussel Farms: Proposed coastal permit applications, 

technical evaluation of assessments of environmental effects. AEE / Mussel Farms / 

Coromandel, 06 Worleys 1995. Report to Environment Waikato. Hamilton, NZ: Brian 

T. Coffey & Associates. 


Copy held: Brian T. Coffey and Associates; Environment Waikato 

Coffey, B.T. (1995). State of the environment monitoring proposal: Coastal habitat quality, 

1995/96 mussel programme. Proposal for heavy metal baseline. Coastal SEM / 

Environment Waikato, December 1995. Report for Environment Waikato. Hamilton, 

NZ: Brian T. Coffey & Associates. 


Copy held: Brian T. Coffey & Associates, Environment Waikato 

Coffey, B.T. (1996). Marine farming study: for the Coastal Marine Area between Kaiaua and 

Colville Bay, Firth of Thames, Western Coromandel Peninsula. Part I: Ecological and 

navigational considerations Environment.Waikato; CMA. W.Coromandel, September, 

1996. Report for Worley Consultants. Hamilton, NZ: Brian T. Coffey & Associates. 


Copy held: Brian T. Coffey and Associates; EQ 

Coffey, B.T. (1996). State of the environment monitoring proposal: Coastal habitat quality: 

heavy metal content of Perna canaliculus. Coastal SEM / Environment Waikato, April 

1996. Report for Environment Waikato. Hamilton, NZ: Brian T. Coffey & Associates. 

Subject: Marine farming. Concerns levels of various heavy metals in mussels at a range of 

coastal points encompassing the Waikato region. Includes site in the Firth of Thames. 

Keywords: mussels, Perna canaliculus, SOE, heavy metal 

Copy held: Brian T. Coffey and Associates 


172 

Coffey, B.T. (1997). Analysis of submissions received in response to Environment Waikato 

Marine Farming Study, west coast of the Coromandel Peninsula: Discussion paper for 

consultation purposes. A report prepared for Environment Waikato by a task force 

convened by Worley Consultants Limited, June 1997. Hamilton, NZ: Brian T. Coffey & 

Associates. 


Copy held: Brian T. Coffey and Associates; Environment Waikato, EQ 

Collins, L., & Merrett, M. (1988). Ecology of the ‘rare’ small tree Pomaderris hamiltonii. 

Waikato Conservancy. Landcare Research, 1-27. 


Keywords: Warkworth, Miranda, endemic tree 

Copy held: EQ 


Colman, J.A. (1972a). Food of snapper, Chrysophrys auratus (Forster), in the Hauraki Gulf, 

New Zealand. New Zealand Journal of Marine and Freshwater Research 6(3), 221-39. 

Subject: Fish 

Keywords: snapper (no evidence for two races), no seasonal or gender differences in diet, 

crustaceans, polychaetes, echinoderms, molluscs, Chrysophrys auratus, Hauraki Gulf 

Copy held: EQ 

Colman, J.A. (1972b). Size at first maturity of two species of flounders in the Hauraki Gulf, 

New Zealand. New Zealand Journal of Marine and Freshwater Research 6(3), 240-5. 

Subject: Fish 

Keywords: Rhombosolea plebeia, R. leporina, spawning, Hauraki Gulf, size, maturity, sand 

flounder, yellow belly flounder, minimum size, protection of immature fish 

Copy held: EQ 

Colman, J.A. (1973). Spawning and fecundity of two flounder species in the Hauraki Gulf, 

New Zealand. New Zealand Journal of Marine and Freshwater Research 7, 21-43. 

Subject: Fish 

Keywords: Rhombosolea plebeia, R. leporina, spawning between Tapu and Ponui, Hauraki 

Gulf, eggs in the plankton, changes in ovary weight 

Copy held: EQ 

Colman, J.A. (1974a). Growth of two species of flounders in the Hauraki Gulf, New Zealand. 

NZ Journal of Marine and Freshwater Research 8(2), 351-70. 

Subject: Fish 

Keywords: Rhombosolea plebeia, R. leporina, faster-growing females, otoliths, Hauraki Gulf 

Copy held: EQ 

Colman, J.A. (1974b). Movements of flounders in the Hauraki Gulf, New Zealand. New 

Zealand Journal of Marine & Freshwater Research 8(1), 79-93. 

Subject: Fish 

Keywords: Rhombosolea plebeia, R. leporina, local movements offshore to spawn in winter & 

spring, onshore in summer, Thames set-net fishery, tagging, trawling surveys, landings. 

Copy held: EQ 

Cox, G.J. (1977). Utilisation of New Zealand mangrove swamps by birds. Unpublished master’s 

dissertation, University of Auckland, Auckland, New Zealand. 


173 

Subject: Birds, mangroves 

Cox, S.H. (1877). Report on Waikato District, New Zealand: Geological Survey. Geological 

Exploration 10, 11-26. 


Cranfield, H.J., Gordon, D.P., Willan, R.C., Marshall, B.A., Battershill, C.N., et al. (1998). 

Adventive marine species in New Zealand. NIWA Technical Report 34. [ISSN 1174- 

2631] 

Subject: Benthic ecology, oceanography 

Copy held: EQ 

Creese, R., Hooker, S., De Luca, S., & Wharton, Y. (1997). Ecology and environmental impact 

of Musculista senhousia (Mollusca: Bivalvia: Mytilidae) in Tamaki estuary, Auckland, 

New Zealand. New Zealand Journal of Marine and Freshwater Research 31, 225-236. 

Subject: Benthic fauna. Similar beds of Musculista found in the Miranda Ramsar area need 

more investigation 

Keywords: benthic fauna, Asian date mussel, Musculista senhousia, environmental impact, 

ecology, distribution. 

Copy held: EQ 

Crisp, P., Daniel, L., & Tortell, P. (1990). Mangroves in New Zealand: Trees in the tide. 

Wellington, NZ: GP Books. 


Keywords: mangrove, Avicennia marina, ecology 

Copy held: EQ 

Cromarty, P., & Scott, D.A. (1996). A directory of wetlands in New Zealand. Wellington, NZ: 

Department of Conservation. 

Subject: Wetlands 

Crosby, A., & Loughlin, S. (1991). Site Survey Report West Bank of the Waihou River. 

Hamilton, NZ: A.Crosby. 

Subject: Archaeological survey prehistoric and early historic Waihou River settlement. 

Copy held: University of Waikato GN875.N45A82C76 1991 (NZ Collection, outsize) 

Crossland, J. (1980a). The number of snapper (C. auratus) in the Hauraki Gulf, New Zealand, 

based on egg surveys in 1974-75; 1975-76. Wellington, New Zealand: Fisheries 

Research Division, MAF. 

Subject: Fish 

Keywords: snapper, Chrysophrys auratus 

Copy held: University of Waikato SH318.5.A1N43 no.22 (NZ Collection) 

Crossland, J. (1980b). Population size and exploitation rate of snapper, Chrysophrys auratus, in 

the Hauraki Gulf from tagging experiments, 1975-76. New Zealand Journal of Marine 

and Freshwater Research 14(3), 255-61. 

Subject: Fish 

Keywords: fishery survey 

Copy held: EQ 

Crossland, J. (1981). Fish eggs and larvae of the Hauraki Gulf, New Zealand. Wellington, NZ: 

Fisheries Research Division, MAF. 

Subject: Fish 


174 


Crossland, J. (1982). Movements of tagged snapper in the Hauraki Gulf, New Zealand. 

Wellington, New Zealand Fisheries Research Division, MAF. 

Subject: Fish 


Crowley, C.L. (2001). A preliminary survey of fish composition in the Miranda Stream, New 

Zealand. Unpublished Directed Research Project. EcoQuest Education Foundation, 

New Zealand. 

Subject: Fish 

Copy held: EQ 

Curtis, R.J. (1981). Interpretation of a Chenier plain, Firth of Thames. Unpublished master’s 

dissertation, Auckland University, Auckland, New Zealand. 

Radiocarbon dates of inter tidal shelf established that the base of the Miranda Chenier plain is 

4,000 years old and suggests that there has been an absence of tectonic uplift since that time. 


Keywords: geology, Miranda 

Cuthbertson, A.S. (1981) The Hinuera Formation in the southern Hauraki lowland, central 

North Island. Unpublished master’s dissertation, University of Waikato, New Zealand. 


Davidson, R. J., & Brown, D.A. (1999). Ecological report of potential marine farm areas 

located offshore of the west coast of Coromandel Peninsula. Research, Survey and 

Monitoring Report Number 177. Prepared for Environment Waikato by Davidson 

Environmental. 


Keywords: benthic fauna, marine farming, benthic survey, mussels, monitoring report 

Copy held: EQ 

Deimezis, E. (2002). Assessment of four fish sampling methods in an estuarine stream in the 

Firth of Thames. Unpublished Directed Research Project. EcoQuest Education 

Foundation, New Zealand. 

Subject: Fish 

Copy held: EQ 

Dekinga, A. & Piersma, T. (1993). Reconstructing diet composition on the basis of 

faeces in a mollusc-eating wader, the Knot Calidris canutus. Bird Study 40, 144- 

156. 

de Lange, P.J. (1989). Late quaternary developments of the Kopouatai peat bog, Hauraki 

lowland, and some paleo environmental inferences. Unpublished master’s dissertation, 



de Lange, P.J., & Cameron, E.K. (1997). Auckland regional threatened plant list. Auckland 

Botanical Society Journal 52. 


de Lange, P.J., Heenan, P.B., Given, D.R., Norton, D.A., Ogle, C.C., Johnson, P.N., & 

Cameron, E.K. (1999). Threatened and uncommon plants of New Zealand. New 

Zealand Journal of Botany. 37, 603-628. 



175 

de Lange, P.J., & Lowe, D.J. (1990). History of vertical displacement of Kerepehi Fault at 

Kopouatai bog, Hauraki lowlands, New Zealand since c.10, 700 years ago. New 

Zealand Journal of Geology and Geophysics 33(2), 277-285. 


de Lange, W.P., & de Lange, P.J. (1994). An appraisal of factors controlling the latitudinal 

distribution of mangrove (Avicennia marina var. resinifera) in New Zealand. Journal of 

Coastal Research 10(3), 539-548. 


Keywords: mangroves, Avicennia marina 

Copy held: EQ (reprint), University of Waikato LG741.5.W3R4 no2773 (in storage) 

de Lange, P.J., Norton, D.A., Heenan, P.B., Courtney, S.P., Molloy, B.P., Ogle, C.C., Rance, 

B.D., Johnson, P.N., & Hitchmough, R. (2004).Threatened and uncommon plants of 

New Zealand. New Zealand Journal of Botany 42, 45-76. 

Dellow, U.V. (1954). Marine algal ecology of the Hauraki Gulf, New Zealand. Volume 1. 

Unpublished doctoral dissertation, University of Auckland, Auckland, New Zealand. 


Keywords: marine algae, ecology, Hauraki Gulf, intertidal zones 

Copy held: EQ 

Department of Conservation. (1997). Kaupapa Atawhai Strategy: Atawhai Ruamano 

2000.Wellington. 


Keywords: Treaty of Waitangi, biodiversity conservation, relationships with Maori, cultural 

heritage, visitor services, public awareness, Maori perspectives 

Copy held: EQ 

Dewes, E.R.. (1991). Volcanic geology of Miranda. Unpublished master’s dissertation, 


Subject: Geology. Presents and discusses the variety of volcanic rock types of the Miranda 

Formation. Inferences with regard to origins and tectonics. Geological map (1:25,000) of the 

area included. 

“Miranda lies within the central portion of the Kiwitahi Volcanic Zone, one of the three 

provinces which make up the Hauraki Volcanic Region.” ... “The Kiwitahi Volcanics form a 

late Miocene (12.97Ma to 5.52Ma) chain of volcanic fields aligned along the NNW tending 

margin of the Hauraki Rift.” 

“...The Kiwitahi eruptives and Miranda Formation lie in a region which is considered to be 

tectonically active, with tectonic uplift along the western Firth of Thames coastline and 

subsidence in the Firth of Thames. Terraces in the field area expose some 20 m of the Kiwitahi 

eruptives, Miranda Formation. Pocknell et al., (1986) contend that the terraces are marine in 

origin, owing to their proximity to the present coastline and were formed during interglacial 

high sea levels.” 

Keywords: volcanic geology, tectonics, Miranda Volcanic Region, Kiwitahi volcanics, Hauraki 

Rift 

Copy held: University of Waikato QE527. D48 1991 

Diggles, B.K., Chang, H., Smith, P., Uddstrom, M., & Zeldis, J. (2000). A discolouration 

syndrome of commercial bivalve molluscs in the waters surrounding the Coromandel 

Peninsula. Final Research Report for Ministry of Fisheries Research Project, MOF 

199/04B NIWA, Wellington. NZ. 



176 

Keywords: scallops, oysters, mussels, mantle and gill discolouration, scallop fishery, Hauraki 

Gulf 

Copy held: EQ 

Dravitzki, M.L. (1987). Littoral drift of mixed sand and gravel sediment on four gravel delta 

fans, western Coromandel, New Zealand. Unpublished master’s dissertation, University 

of Waikato, New Zealand. 


Copy held: University of Waikato GB458.55.D7 1987 

Duke, N.C. (1991). A systematic revision of the mangrove genus Avicennia (Avicenniaceae) in 

Australasia. Australian Systematic Botany 4, 299-324. 


Duncan, L. (1982). Auckland commercial fishermen and the Hauraki Gulf snapper fishery. 

Department of Sociology, University of Auckland. 

Subject: Fish 

Copy held: University of Waikato HM48.W6. No.10 (NZ Collection). 

EcoQuest Education Foundation. October 1999, March 2000, October 2000, March 2001, June 

2001. Unpublished Directed Research Projects. Auckland, New Zealand: EcoQuest Education 

Foundation. 

Edwards, F. (1991). The Hauraki Gulf: Auckland’s dumping ground. Forest and Bird, 22(4), 

16-20. 

Subject: Pollution 

Keywords: pollution 

Copy held: EQ 

Elder, R.D. (1976). Studies on age and growth, reproduction and population dynamics of red 

gurnard (Chelidonichtyhys kumu [Lesson & Garnot]) in the Hauraki Gulf, New 

Zealand. Fisheries and Research Division / MAF, Wellington. 

Subject: Fish 

Copy held: University of Waikato. SH318.5.A1N43 No.12 (NZ Collection). 

Environment Waikato. (1992). Local planning issues Waikato Region: Waikato River, Piako 

Catchment, Taupo Basin, Hamilton Basin,Coromandel Peninsula. Environment 

Waikato, Hamilton, New Zealand. 


Copy held: University of Waikato TC522.6.W3L62 1992 (NZ Collection, outsize). 

Environment Waikato. (1997). Proposed Regional Coastal Plan. Hamilton, New Zealand: 

Waikato Regional Council. 


Keywords: marine farming, natural character, habitat, coastal processes, water quality, 

foreshore, seabed, natural hazards, public access, cross-boundary management, monitoring 

Copy held: EQ 

Environment Waikato. (2000). Proposed Variation – Marine Farming.Regional Coastal Plan. 


Keywords: benthic ecology, structures, onshore facilities, noise, water quality, organic waste, 

seabed disturbance, navigation, development 

Copy held: EQ 


177 

Estcourt, I.N. (1976). Bibliography of scientific studies of New Zealand mainland estuaries, 

inlets, lagoons, harbours and fiords. Miscellaneous Publications of NZOI No 75. 

Wellington, NZ: New Zealand Oceanographic Institute, DSIR. 


Keywords: estuaries, harbours, bibliography 

Flint, S.B. (1998). Sediment trapping in the near-shore coastal environment. Unpublished 

master’s dissertation, University of Waikato, Hamilton, New Zealand. 196pp. 

Subject: Sedimentation: Useful reference with respect to methodology, particularly if suspended 

particulate matter is to be collected at several places along the river-mouths / inshore. Location 

not directly relevant to Ramsar site. 

“Sediment trapping experiments undertaken to investigate the use of traps in wave-dominated 

turbulent environments at locations ranging from the surf zone to the shoreface/inner shelf. In 

conjunction, trap calibration experiments and investigations of the flow around a trap were 

undertaken in conditions similar to those encountered during the trapping studies.” 

Keywords: sediment trapping 

Copy held: University of Waikato QD79.S4F55. 1998 

Fox, M.E., Roper, D.S., & Thrush, S.F. (1988). Organochlorine contaminants in the surficial 

sediments of Manukau Harbour, New Zealand. Marine Pollution Bulletin 19, 333-336. 

Subject: Pollution, sedimentation 

Keywords: pollution, organochlorides, sediments, Manukau Harbour, contaminants 

Copy held: University of Auckland 

Francis, M.P. (1995). Spatial and seasonal variation in the abundance of juvenile snapper in the 

north-western Hauraki Gulf. New Zealand Journal of Marine and Freshwater Research 

29, 565-579. 

Subject: Fish 

Keywords: Pagrus auratus abundance, sediments 


Frazer, L. & Adams, J.H. (1907). Geology of the Coromandel Subdivision, Hauraki, New 

Zealand. New Zealand Geological Survey Bulletin 4, 154. 


Frazier, S. (1996). An overview of the world’s Ramsar sites. Wetlands International, Publ.39. 

58pp. 

Subject: Policy and planning. Introduction to the Ramsar Convention and the 

number/distribution/size of Ramsar sites. Discussion centres on different wetland types and 

their importance, human uses of the sites, and changes in ecological character at Ramsar sites. 

Keywords: RAMSAR, wetlands, biodiversity, human impacts, ecological character 

Copy held: Department of Conservation, Hamilton. 

Frazier, S. (Ed.). (1999). A Directory of Wetlands of International Importance designated 

under the convention on wetlands of international importance especially as waterfowl 

habitat (Ramsar, 1971). Compiled by Wetlands International for the Seventh Meeting 

of the Compilation of United Kingdom Ramsar site accounts. Coordinated by the Joint 

Nature Conservation Committee on behalf of the statutory nature conservation bodies 

and territorial government departments in the UK. 

Galbraith, M.P. (1992). A new centre for environmental education. Nature Notes 4. Miranda 

Naturalists’ Trust. 



178 

Copy held: Miranda Shorebird Centre, EQ 

Gibb, G. (1986). A New Zealand Regional Holocene eustatic sea-level curve and its implication 

to determination of vertical tectonic movements. Royal Society of New Zealand Bulletin 

24, 377-395. 


Gibb, J.C. (1979). Late Quarternary shoreline movements in New Zealand. Unpublished 

doctoral dissertation, Victoria University, Wellington, New Zealand. 

Subject: Geology. Greig (1982) notes: “Gibb stated that sea level reached its present stand 6,500 

years BP and has varied less than 1 m since then. He considers the level recorded by Schofield 

in the Firth of Thames to represent tectonic uplift causing a relative sea level fall.” 

Gibbs, M.M., & Vant, W.N. (1997). Seasonal changes in factors controlling phytoplankton 

growth in Beatrix Bay, New Zealand. New Zealand Journal of Marine and Freshwater 

Research 31, 237-48. 


Keywords: marine farming 

Glasby, G.P., Stoffers, P., Walter, P., & Renner, R.M. (1988). Heavy metal pollution in 

Manukau and Waitemata Harbours, New Zealand. New Zealand Journal of Marine and 

Freshwater Research 22, 595-611. 


Keywords: pollution, heavy metal, Manukau Harbour, Waitemata Harbour 


Godfriaux, B.L. (1969). Food of predatory demersal fish in Hauraki Gulf. 1: Food and feeding 

habits of snapper. New Zealand Journal of Marine and Freshwater Research 3, 518- 

544. 

Subject: Fish 

Keywords: predatory, feeding habits, snapper 

Copy held: EQ 

Godfriaux, B.L. (1970). Food of predatory demersal fish in Hauraki Gulf. 2: Five fish species 

associated with snapper. New Zealand Journal of Marine and Freshwater Research 

4(3), 248-266. 

Subject: Fish 

Keywords: fish associated with snapper, trevally, gurnard 

Copy held: EQ 

Godfriaux, B.L. (1970). Food of predatory demersal fish in Hauraki Gulf.3: Feeding 

relationships. New Zealand Journal of Marine and Freshwater Research 4(4), 325-336. 

Subject: Fish 


Gordon, D. (Ed.) (2001). New fish species invade our estuaries. Biodiversity Update 4: 6. 

Subject: Fish 

Keywords: exotic marine organisms, goby, NIWA 

Copy held: EQ 

Gordon, D. (Ed.). (2002). Finned bio-invader surfaces in the Coromandel. Biodiversity Update 

1:5. 


179 

Subject: Fish 

Keywords: new goby species, NIWA, biodiversity hotspots 

Copy held: EQ 

Grange, K.R. (1977). Littoral benthos-sediment relationships in Manukau Harbour, New 

Zealand. New Zealand Journal of Marine and Freshwater Research, 11, 111-23. 


Keywords: plankton, benthic ecology 


Grange, K.R. (1979). Soft-bottom macrobenthic communities of Manukau Harbour, New 

Zealand. New Zealand Journal of Marine and Freshwater Research 13, 315-329. 


Keywords: benthic fauna 

Copy held: EQ 

Grant-Mackie, J.A. (1979). Ancient life of the Auckland area. In: Brock, P.F.(Ed.). Natural 

History of Auckland. Auckland War Memorial Museum handbook. Auckland, NZ. 

Subject: History, vegetation 

Keywords: plankton 


Greenway, J.P.C. (1969). Surveys of mussels (Mollusca: Lamellibranchia) in the Firth of 

Thames, 1961-67. New Zealand Journal of Marine and Freshwater Research 3, 304- 

317. 


Keywords: distribution, relative density, Matingarahi Point, settlement, regeneration, declining 

yields. 

Copy held: EQ 

Greig, D.A. (1982). Sediments and recent geological history of the Hauraki Gulf, Firth of 

Thames and Colville Channel, North Island, New Zealand. Unpublished master’s 

dissertation, University of Waikato. Hamilton, New Zealand. 138pp. 

Subject: Geology. Greig used available echograms, sub-bottom profiler records, side-scan sonar 

records, sample grabs and short cores (collected during a cruise of the RV Tangaroa in 1980) 

and previously collected data from a cruise by the HMNZS Tui (1975) to: map and describe 

sediment distribution patterns in the Colville Channel, Hauraki Gulf and Firth of Thames; 

describe mineralogy of the sediments with the view to identifying provenance; and to develop 

an understanding of the geological history of the study area through the Pleistocene to present 

times. 

Abstract: “Three sedimentary facies are recognised in the modern marine sediments flooring the 

Hauraki Gulf, Firth of Thames and Colville Channel. 1) Colville Channel Facies; a coarse, 

skeletal, carbonate-rich, gravely sand body, which is palimpsest in character and restricted to 

the Colville Channel. 2) Central Gulf Facies; a gravel carbonate, muddy sand extending 

southwards from the outer Hauraki Gulf, as a central belt, into the Firth of Thames. These 

sediments, which were deposited at a slightly lower sea level than the present level, are being 

actively covered by modern marine muds in the Firth of Thames and Inner Hauraki Gulf, and 

are partially covered by the Colville Channel Facies in the eastern outer Hauraki Gulf. 3) Inner 

Gulf/Firth of Thames Facies; a modern terrigenous sandy mud-mud blanket actively infilling 

the Firth of Thames and Inner Hauraki Gulf, and prograding northwards. 

The terrigenous component of these sediments is dominantly feldspar, rhyolithic rock fragments 

and quartz, and derived from the rhyolitic lavas of the Central North Island. Material of local 


180 

origin occurs in lesser quantities. Recent phosphatic casts and aggregates in sediments of the 

Central Gulf Facies in the northern Firth of Thames are considered to have formed 

authigenically. A strong, fine pumiceous glass component in the sediments, particularly those of 

the Hauraki Gulf, may be of air-fall origin. 

Palynological analysis of a peat-horizon collected from sub-bottom sediments of the northern 

Firth of Thames indicates that mangrove (Avicennia) swamps and Northland-type rainforests 

surrounded the Firth of Thames and Hauraki Gulf during the last interglacial period. This is the 

first reported occurrence of the mangrove (Avicennia) pollen in Quarternary sediments of the 

region, and in particular the Firth of Thames and Hauraki Gulf. 

Pumiceous alluvial sands, comparable to the Hinuera Formation underlie the northern Firth of 

Thames. Echograms in the vicinity of these sediments, and to the south, show sub-bottom 

horizons are constantly tilted up to ten degrees toward the east between two linear depressions 

considered fault traces of the Kerepehi and Hauraki Faults. This suggests tectonic deformation 

of the area has been active in the recent past.” 

Keywords: marine sediments, sedimentology, detrital mineralogy, geology, Hauraki Gulf, Firth 

of Thames, Colville Channel. 

Copy held: University of Waikato GC399.G74 1982 

Greig, M.J. 1988 Circulation in the Hauraki Gulf, New Zealand. New Zealand Journal of 

Marine and Freshwater Research 24, 141-150. 


Keywords: currents, circulation, tides, Hauraki Gulf 


Greig, M.J. & Proctor, R. (1988). A numerical model of the Hauraki Gulf, New Zealand. New 

Zealand Journal of Marine and Freshwater Research 22, 379-390. 


Copy cited in: Liefting, (1997) 

Griffiths, G.A. & Glasby, G.P. (1985). Input of river-derived sediment to the New Zealand 

Continental Shelf. I. Mass. Estuarine, Coastal and Shelf Science 21, 773-787. 

(See also: Estuarine, Coastal and Shelf Science 27, 397-411). 


Hackwell, K.R. (1989). New Zealand Mangroves: State-of-the-Art-Report. Wellington NZ: 

Department of Conservation for the Nature Conservation Council. 


Keywords: mangroves, Avicennia marina 

Copy held: EQ 

Hadfield, J.C. (1990). Preliminary evaluation of the Piako Catchment hydrology. Waikato 

Regional Council. 


Copy held: University of Waikato S625. N45W23 no.1990/24 (NZ Collection, outsize). 

Handley, S.J. (1998). Power to the oyster: Do spionid-induced shell blisters affect conditions in 

subtidal oysters? J. Shellfish Research 17(4), 1093-1099. 

Hannah, J. (1988). Analysis of mean sea level trends in New Zealand from historical data. NZ: 

Department of Survey and Land Information Report No.2. 



181 

Harris, R.W. (1975). Summary of water quality results from January 1973 to March 1975 for 

the Waihou River, its southern tributaries and the harbours of the Coromandel 

Peninsula.Te Aroha: Hauraki Catchment Board and Regional Water Board. 

Subject: Water quality 

Keywords: Waihou River, water quality testing 


Harrison Grierson Consultants, Ltd. (1988). Proposed barge loading conveyor, Kaiaua – 

environmental impact assessment supporting documentation for town planning and 

Harbours Act applications. Report prepared for W. Stevenson & Sons, Ltd., Auckland. 


Keywords: intertidal zone, harbour dredging and maintenance, pier construction, sight lines, 

visual impacts, navigation hazards, sedimentation 

Copy held: Environment Waikato, Auckland Regional Council, Department of Conservation 

Hauraki Maori Trust Board. (1999). Hauraki Customary Indicators Report. Ministry for the 

Environment, Technical Paper No.57. Wellington. 


Keywords: Hauraki Maori society, Te Ao Maori o Hauraki, Waihou River, fisheries abundance 

and use, Tikanga Maori, sustainability, environmental performance indicators 

Copy held: EQ 

Hauraki Whanui. (2004). Whaia te Mahere Taiao a Hauraki (Hauraki Iwi Environmental 

Plan). In collaboration with Ministry for the Environment, Department of Conservation 

and Environment Waikato 

Copies held: Ministry for the Environment; Department of Conservation; and Hauraki Maori 

Trust Board, Paeroa) 

Healy, T.R. (1996). Sea level rise and impacts on nearshore sedimentation: an overview. 

Subject: Oceanography. Reprinted from Geol Runsch,1996. 

Copy held: University of Waikato LG741.5.W3R4 no. 4431 

Healy, T.R., Dell, P.M., Willoughby, A.J. (1982). Coromandel coastal survey. Volumes 1&2. 

Te Aroha, NZ: Hauraki Catchment Board. 


Keywords: beach erosion 

Copy held: University of Waikato T522.6.H3R425, 114, 115 (NZ Collection, outsize). 

Healy, T.R. and Harada, K. (1991). Enclosed and semi-enclosed seas. Journal of Coastal 

Research 7(1), 1-6. 


Heath, R.A. (1977). Phase distribution of tidal constituents around New Zealand. New Zealand 

Journal of Marine and Freshwater Research 11: 383-392. 


Henderson, J. (1918). Notes on the geology of the Waikato Valley near Maungatautiri. New 

Zealand Journal of Science and Technology 1,56-60. 



182 

Henriques, P.R. (1980). Faunal community structure of eight soft shore, intertidal habitats in 

the Manukau Harbour. New Zealand Journal of Ecology 3, 97-103. 


Keywords: benthic fauna, Manukau Harbour 

Copy held: EQ 

Henshaw, G.S. (1989). Sorption of trace metals on suspended sediments in the Waihou River. 

Unpublished master’s dissertation, Auckland University, Auckland, New Zealand. 


Hochstein, M.P., Tearney, K., Rawson, S., Davey, F., Davidge, S., Henry, S., & Blackshall, D. 

(1986). Geophysical structure of the Hauraki Rift (New Zealand). Royal Society of New 

Zealand Bulletin 24, 332-348. 


Hochstein, M.P., & Nixon, I.M. (1979). Geophysical study of the Hauraki Depression, North 

Island, New Zealand. New Zealand Journal of Geology and Geophysics 22(1), 1-19. 


Copy: Reference cited in Greig (1982) and Liefting (1997) 

Horigan, C. (2002). Fishing in the mud: A survey of the fishes of Miranda Stream, Firth of 

Thames. Unpublished Directed Research Project. EcoQuest Education Foundation, New 

Zealand. 

Subject: Fish 

Keywords: estuaries, juvenile fish, Firth of Thames, Miranda Stream 

Copy held: EQ 

Hume, T.M., and Dahm, J. (1992). An investigation of the effects of Polynesian and European 

landuse on sedimentation in Coromandel estuaries. Consultancy report prepared for 

Department of Conservation, Northern Regional Office. 56pp. 


Iglesias, J.I.P., Urrutia, M.B., Navarro, E., & Ibarrola, I. (1998). Measuring suspension feeding 

and absorption in suspension-feeding bivalves: an appraisal of the biodeposition 

method. Journal of Experimental Marine Biology and Ecology 219, 71-86. 


Keywords: aquaculture 


Ika Consultants Ltd. (June 1990). Proposed mussel farm development in the Firth of Thames: 

Environmental evaluation. Hauraki Maori Trust Board. 


Ika Consultants Ltd. (June 1990). Mussel farm license application in the Firth of Thames: 

Environmental Evaluation. 


Jasperse, J.A. (1993). Marine toxins and New Zealand shellfish: Proceedings of a workshop on 

research issues, 10-11 June 1993. Royal Society of New Zealand, Wellington. 


Keywords: marine toxins 



183 

Jillett, J.B. (1966). Plankton of the Hauraki Gulf. Unpublished doctoral dissertation, University 

of Auckland, Auckland, New Zealand. 


Keywords: plankton, Hauraki Gulf, pelagic organisms 

Copy held: EQ 

Jillett, J.B. (1971). Zooplankton and Hydrology of Hauraki Gulf, New Zealand. DSIR Bulletin 

204. New Zealand Oceanographic Institute Memoir no.53. 

Subject: Oceanography. Detailed account of near shore plankton populations in northern waters, 

and their variability with respect to changes in environment and season. Although Firth of 

Thames recognised as part of the Gulf, no samples for this publication were taken south of 

Waitemata Harbour. Some references and details regarding general climatic conditions and 

water temperatures/salinity may be applicable. Good picture of surface currents around NZ, 

bathymetry and land catchments of Gulf/Firth of Thames. 

Jones, C.G. (1995). Recreational boating and conservation islands in the Hauraki Guilf. 



Keywords: planning 

Copy held: EQ (abstract) 

Katz, W. (1999). Wading birds at Miranda: A study of human and environmental impacts. 

Observations of eastern bar-tailed godwits [Limosa lapponica] on a Miranda intertidal 

mudflat and Chenier. Unpublished Individual Research Project. Auckland, NZ: 

EcoQuest Education Foundation. 


Keywords: Chenier plain, agricultural impacts, wader habitat, mudflats, sodium 

Copy held:EQ 

Kiwi Gold Exploration Co. Ltd. (1987). Preliminary geological assessment, E.L. 33 290 Firth 

of Thames, New Zealand. Prepared by the Applied Geology Association Ltd. 


Kuchler, A.W. (1972). The mangrove in New Zealand. New Zealand Geographic 28: 113- 127 


Lang, R.J. (1974). Planning for marine farming with particular reference to the west coast of 

the Cormandel Peninsula. A report to the Hauraki Gulf Maritime Park Board. Lands 

and Survey, Auckland. 31pp. 

A report investigating the management options for coastal waters suitable for marine farming 

and in particular the cultivation of mussels, the effects of marine farming on the safety, health 

use, benefit and enjoyment of the water by other users and effects of land use in the catchment 

on marine farming, interaction of competing interests 


Keywords: Effects of marine farming, mussel cultivation 

Copy held: EQ 

Larcombe, M. (2001). Assessment of effects of a gravel seep diffuse disposal system (Thames 

Sewage Treatment Plant). Unpublished report prepared for the Thames Coromandel 

District Council, August 2001. 11 pp. 

Leathwick, J.R. (1998). Defining ecosystems for biodiversity and environmental management. 

Information: Landcare Research Newsletter 10 November. 

Subject: Vegetation, policy and planning 


184 

Keywords: environmental domains, indigenous biodiversity, ecosystem remnants 

Copy held: EQ 

Leathwick, J.R., Clarkson, B.D., & Whaley, P.T. (1995). Vegetation of the Waikato Region: 

Current and historical perspectives. Unpublished Landcare Research contract report: 

LC9596/022. Manaaki Whenua - Landcare Research, Hamilton. 

Subject: Vegetation. This report maps the current composition and extent of natural vegetation 

in the Waikato Region at a scale of 1:50 000 using both published and unpublished information, 

updated with recent aerial photography. To facilitate comparison of current vegetation with that 

present at the time of European settlement, vegetation cover likely to have occurred in 1840 is 

mapped. In addition, the extent of both 1840 and current vegetation in relation to bioclimatic 

zones, Ecological Districts and local authorities is mapped. 

Key findings documented in this report include: 

� Substantial areas of vegetation were already modified at the time of European settlement. 

� At the time of European settlement, primary forest was still the predominant vegetation 

cover in approximately two-thirds of the Ecological Districts. 

� Since European settlement indigenous vegetation has been steadily reduced in extent, and 

now covers approximately 25% of its former total area; only 18% remains in the lowlands. 

� Approximately 30% remains of the area once in forest, and logging has modified 40% of 

this. Only 6% of the former lowland and coastal forests remain unmodified. 

� Removal of primary forest has been almost complete in some Ecological Districts. 

� Secondary forest, scrub, and shrubland have together been reduced to less than 20% of their 

former extent. 

� Wetlands have been reduced to approximately 25% of their former extent, but in the 

Hamilton and Waipa Ecological Districts they have been almost entirely drained for 

agriculture, with less than 1% now remaining. 

Keywords: Waikato Region, vegetation changes, bioclimatic zones, planning 

Copy held: Department of Conservation, Hamilton 

Ledwin, S. (2002). Muddy waters: a comparative interpretation of temporal variance in the 

estuarine fish community at Miranda Stream. Unpublished Directed Research Project. 

Auckland, NZ: EcoQuest Education Foundation. 

Subject: Fish 

Copy held: EQ 

Liefting, H.C.C. (1988). Development of the Kaiaua-Miranda Chenier plain. Unpublished 

master’s dissertation, University of Waikato, Hamilton, N.Z. 112pp. 

Subject: Geology. Abstract: “ A conceptual model of Chenier ridge formation has been 

developed for the Kaiaua-Miranda Chenier plain on the western coastline of the Firth of 

Thames, North Island, New Zealand. The conceptual model associates fair weather and storm 

induced sediment transport with different phases of Chenier ridge building process” (fair 

weather is associated with vertical building of the Chenier ridges, while storm events are 

associated with horizontal building of the ridges). “A numerical model comparing current 

patterns during fair weather and storm conditions has been utilised to help understand surficial 

sediment distribution in the Firth of Thames, which influences sediment flux for the prograding 

Chenier plain”... “Coastal erosion encroaching on public infrastructure and private property 

along parts of the Kaiaua-Miranda coastline is a short term problem associated with storm 

events. The long-term trend of the Kaiaua-Miranda coastline is progradation, as evidenced by 

the continuing development of Cheniers. Existing coastal protection measures (groins) along the 

coastline are recommended to be removed as along-shore transport is negligible during fair 

weather conditions. The groins also exacerbate storm effects, and result in the loss of natural 

character along the Kaiaua-Miranda coastline. The Kaiaua-Miranda Chenier plain is a unique 


185 

landform which holds valuable information for present and future generations and must be 

allowed to continue to form naturally.” This thesis deals with surficial sediments of the Firth of 

Thames, formation of the Chenier plain - detailing sediment composistion and sediment 

sources, and current and sediment flow. 

Keywords: New Zealand, Firth of Thames, sedimentation, deposition, geology 

Copy held: University of Waikato GC399.L54 1998 

Liefting, R., de Lange, W., & Dahm, J. (1997). Development of the Miranda-Kaiaua Chenier 

plain, Firth of Thames, New Zealand, and implications for coastal hazard management. 

Combined Australasian Coastal Engineering and Ports Conference. Christchurch, New 

Zealand, 1997. 

Subject: Geology. Abstract: “This paper examines the hypothesis that Chenier ridges between 

Kaiaua and Miranda may provide useful design information on the hazard risk posed by coastal 

inundation. The ridges have been dated and display distinct variations in Chenier width and 

height with age. These changes have been attributed to a ~1m drop of mean sea level during the 

last 3600 years. However, modern coastal dynamics sediment composition of the ridges and 

historic storm surge all suggest that the Chenier ridge elevations are primarily determined by 

wave action and elevated water levels. Numerical simulations of storm surges and wave 

propagation in the Firth of Thames are being undertaken to further develop understanding of the 

relationship between wave action and elevated water levels and Chenier ridge formation and 

development.” 

Keywords: Chenier ridge formation, Chenier ridge morphology, storm surges and coastal 

erosion / accretion processes, coastal hazard risk, hydrodynamic numerical model 3DD 

Copy held: University of Waikato (reprint.) 

Livingston, M.E. (Ed.). (1987). Preliminary studies on the effects of past mining on the aquatic 

environment, Coromandel Peninsula. 

Subject: Sedimentation, pollution 

Copy held: EQ (BB) University of Waikato S622.W324 no.104 (NZ Collection, outsize) 

Lundquist, C., Chiaroni, L., Halliday, J., & Williston, T. (2004). Identifying areas of 

conservation value in the Waikato coastal marine environment. NIWA Client Report: 

HAM2004-039, June 2004. 

Copy held: Waikato Conservancy, Department of Conservation) 

Lyons, R.R. (1932). Notes on the geology of the Mangatangi and Mangatawhiri District, 

Auckland, New Zealand. New Zealand Journal of Science and Technology 13(5), 276- 

277. 


Macdonald, N. (1953). Curlew at Miranda. Notornis 5(6),195. 

Subject: Birds. “The first curlew (Numenius madagascariensis) to be observed at the Firth of 

Thames for some years were seen feeding on a muddy lagoon near the Miranda limeworks on 

6/6/53...” 

Keywords: Curlew, Numenius madagascariensis, Miranda. 

Copy held: EQ 

Male, A.G.R., & Cochrane, G.R. (1978). Analysis of suspended sediment patterns in the Firth 

of Thames. In Ellis, P.J. & Thomas. L.L. (Eds.) Landsat II over New Zealand. DSIR 

Bulletin 221, 411-413. 

Subject: Sedimentation. Greig (1982): “suspended sediment distribution in the Firth of Thames 

show the greatest concentrations are along the eastern coastal areas, while suspended mud is 

deposited predominantly along the southern and western foreshores. Here they form extensive, 


186 

gently graded mudflats where coastal progradation is evident, particularly in the development of 

the Miranda Chenier plain.” 

Keywords: suspended sediment mapping, deposited beach material, sediment matrix, circulation 

patterns, mixing characteristics of the water 

Marchant, S., & Higgins, P. J. (Eds.). (1993). Handbook of Australian, New Zealand and 

Antarctic Birds. Volume 2. Raptors to Lapwings. Melbourne, Australia: Oxford 

University Press. 

Maxwell, G.S. (1971). Mangrove mortality at Piako:Final report, July 14 1971. Botany 

Department, University of Auckland, Auckland. 


Keywords: mangrove, Avicennia marina, Piako, die-back 

Maxwell, G.S. (1971). A Phytophthora sp. in mangrove communities at Piako, N.Z. 



Maxwell, G.S. (1984). The Okahuiti mangrove ecosystem, Waiheke Island. Unpublished Report 

for the City Council, Auckland, N.Z. 


McGlone, M., Nelson, M.S., & Hume, T.M. (1978). Palynology, age and environmental 

significance of some peat beds in the upper Pleistocene Hinuera formation, South 

Auckland, New Zealand. Journal of the Royal Society of New Zealand 8, 385-393. 


Keywords: Hinuera formation, sediments, peat beds, upper Pleistocene 

Copy held: EQ 

McKenzie, H.R. (1965). Broad-billed sandpiper in the Firth of Thames in winter. Notornis 

12(1), 55. 

A broad-billed sandpiper (Limicola falcinellus) spent most of 1964 in association with other 

small waders, especially wrybills (A.frontalis) on the western shore of the Firth of Thames. 


Keywords: broad-billed sandpiper, Limicola falcinellus, waders, Firth of Thames. 

Copy held: EQ 

McKenzie, H.R. (1965). Little whimbrel at Miranda. Notornis 12(2), 110-111. 


Keywords: little whimbrel, Numenius minutus, Miranda. 

Copy held: EQ 

McKenzie, H.R. (1967). Census records of godwit for Firth of Thames and Manukau harbour. 

Notornis 14(1), 18-21. 


Keywords: godwit, Firth of Thames, Manukau harbour 

Copy held: EQ 

McKenzie, H.R. (1967). Census records of Pacific golden plover for Firth of Thames and 

Manukau harbour. Notornis 14, 215. 


Keywords: Pacific golden plover, Firth of Thames, Manukau harbour 


187 

Copy held: EQ 

McKenzie, H.R. (1967). The spotted shags of the Coromandel Coast. Notornis 14, 37. 


Keywords: spotted shag, Coromandel 

Copy held: EQ 

McKenzie, H.R. (1968). Census records of the turnstone for Firth of Thames and Manukau 

harbour. Notornis 15, 238-241. 


Keywords: turnstone, Firth of Thames, Manukau harbour 

Copy held: EQ 

Mead, A.P. (1930). Physiography and Geology of the upland west of the Firth of Thames. New 

Zealand Journal of Science and Technology 11(5), 314-317. 


Medway, D.G. (2000). The Reed field guide to common New Zealand shorebirds. Auckland, 

NZ: Reed Books. 

Subject: Birds. Expert summary and description of shorebird localities in New Zealand, 

background on the East Asian-Australasian Shorebird Reserve Network, description, photos and 

details on ecology of shorebirds and waders 

Keywords: shorebirds, shorebird localities, New Zealand shorebirds, arctic shorebirds 

Copy held: EQ (RB) 

Meredith, A. (1990). Piako/Waitoa fisheries: Executive summary. Hamilton, NZ: Environment 

Waikato 

Subject: Fish 

Merrett, M., & Clarkson, B. (1997). Vegetation survey of the foreshore from Miranda to 

Kaiaua. Report by the Waikato Botanical Society, prepared for the Department of 

Conservation, Auckland Conservancy, Auckland, New Zealand. 28pp. 

Subject: Vegetation. This contract report details the findings of a vegetation survey and analysis 

of the foreshore between Miranda and Kaiaua. Survey carried out by the Waikato Botanical 

Society, covered 150 ha comprising salt marsh vegetation and mangrove forest. Seven 

vegetation types were recognised (mangrove forest, sparsely vegetated young shell banks, 

glasswort salt-marsh, bachelor’s button- Mimulus repens, Carex divisa (wet and dry), ryegrassbur 

medic, and salt marsh ribbonwood-Coprosma. The report includes vegetation maps and a 

species list. 

Keywords: Miranda-Kaiaua Coast, vegetation survey, conservation value assessment, 

conservation, restoration and management of vegetation 

Copy held: EQ 

Middleton, A. (1987). The distribution and weathering of the Martha Mine tailings. 

Unpublished master’s dissertation, University of Waikato, Hamilton, New Zealand. 


Copy held: University of Waikato: Chemistry Department. 

Miller, H.J.M. (1995). The impact of stream discharge on the macrozoobenthos of some inner 

creeks on the Auckland east coast. Auckland, NZ: University of Auckland. 


Keywords: stream discharge, macrozoobenthos, creeks, Auckland east coast. 



188 

Ministry for the Environment. (1997). The state of New Zealand’s environment. Wellington, 

NZ: Ministry for the Environment. 199pp. 


Keywords: place, people, land, waters, air, atmosphere, environmental management, 

biodiversity, harvesting, deforestation, wetland drainage, introductions, pests, weeds, 

Treaty of Waitangi, cultural heritage, RMA, environmental impacts and solutions 

Copy held: EQ 

Ministry of Fisheries (2004). New Zealand Pelagic Fisheries: Medium Term Research 

Plan- 2004/05 to 2006/07. Ministry of Fisheries Science Group & the Pelagic Fisheries 

Management Group. Wellington. Sept. 2004. 

Model, M. (2002). A comparison of four fish sampling methods in an estuarine stream, Firth 

of Thames, New Zealand. Unpublished Directed Research Project. Auckland, NZ: 

EcoQuest Education Foundation. 

Subject: Fish 

Keywords: sampling methods, juvenile fishes, estuaries, Miranda Stream 

Copy held: EQ 

Moore, A., Willis G., & Dickie, B. (September, 2004). The Hauraki Gulf state of the 

environment report 2004. Hauraki Gulf Forum. Published with the administrative 

support of the Auckland and Waikato Regional Councils. 

Morton, J. (1976). Mangroves and reclamation. Wellington: Nature Conservation Council. 


Copy held: University of Waikato QH77.N45N3 no. 13 (NZ Collection, outsize). 

Morton, J. (1983a). The shore and salt marsh plants of Miranda. Miranda Naturalists’ Trust 

Nature Notes 1, Miranda, N.Z. 


Keywords: resident plants, salt marshes, salt meadows, Miranda shore flora 

Copy held: EQ 

Morton, J. (1983b). Invertebrates as a food resource at Miranda Flats. Miranda Naturalists’ 

Trust Nature Notes 2, Miranda, N.Z. 


Keywords: estuarine invertebrates, herbivores, carnivores, detritus, mudflats 

Copy held: EQ 

Naish, T.R. (1990). Late Holocene mud sedimentation and diagenesis in the Firth of Thames: 

bentonites in the making. Unpublished master’s dissertation, University of Waikato, 

Hamilton, New Zealand. 

Subject: Geology. Abstract: “Late Holocene mud sedimentation in the southern Firth of Thames 

has been described from analysis of a number of shallow marine sediment cores. Three distinct 

lithofacies are distinguished on the basis of sediment texture and mineralogy. ... A laterally 

extensive greenish-grey mud, typically bioturbated and massive, with sporadic uncorrelatable 

interbedded shell layers, is termed Firth of Thames mud facies. Nearer shore sediments are 

usually coarser and are subdivided into two facies: 

1) A siliclastic sand facies (river mouth sand facies) comprising more prominent interbeds of 

sand in mud and associated with sedimentation at the mouth of the Waihou River; and 2) a 


189 

mixed terrigenous-carbonate gravel facies (delta fan gravel facies) associated with deposition on 

small delta fans adjacent to streams draining the Coromandel Range. 

The areal distribution of all three facies over the late Holocene has been controlled largely by 

the northward progradation of the Hauraki Lowland, associated with the rapid sediment infilling 

of the Firth of Thames since sea level reached its present height 6500 years BP. From seismic 

evidence, the Holocene muds are up to 10 metres thick. The cores in this study penetrated only 

to 5.5 metres sub bottom depth, and yielded an oldest radiocarbon age of 5000 years BP. The 

age data indicate an average rate of offshore vertical sediment accumulation of 1.5mm/year. Up 

to 15km of progradation of the southern shoreline of the coastal Hauraki Lowland has occurred 

over the late Holocene at an average rate of up to 2.5metres/year, notably from 3500 years BP to 

1200 years BP. Progradation is evidenced by the occurrence of coarsening-upward sequences in 

nearer shore cores of the Firth of Thames, as well as their changing faunal composition, 

particularly the upward increase in abundance of the foraminifer Ammonia beccari, a good 

indicator of brackish water conditions, which suggests a gradual seaward encroachment of the 

fresh water influence of the Waihou River over the late Holocene. 

Basal muds, which are similar in composition to marine sediments of the Firth of Thames are 

overlain by peat dated at 6025 years BP in a peat core from Kopouatai Peat Bog, and suggest 

that marine conditions existed in this inland region of the Hauraki Depression prior to 6025 

years BP. 

Muds range from silty clays to clayey silts and consist principally of volcanic glass, smectite 

and halloysite, with smaller amounts of other volcanic-derived siliclasts and allophane and illite, 

as well as skeletal carbonate (mainly aragonite) and organic matter. A contemporaneous 

decrease in the abundance of volcanic glass (55-15 wt% down core) and increase in smectite 

concentration (8-45 wt % down core) occurs with sub bottom depth. The absence of smectite in 

the bottom sediments of rivers draining the Hauraki Lowland precludes a detrital origin. The 

diagenetic transformation of volcanic glass in smectite in sediments of the Firth of Thames is 

described by a sequential kinetic model, which involves a parabolic dissolution coupled with a 

first order precipitation of smectite via the formation of an intermediate hydrated glass phase.” 

Note: Chapters 1 and 2 are good introductory material to Firth of Thames and regional setting. 

45 cores were taken; 12 were selected for detailed analysis... large number of cores stored at the 

University of Waikato (most were from the eastern side of the Firth, not in RAMSAR site area). 

Livingstone corer, 5cm diameter, up to 5.5 m long. 

Keywords: geology, stratigraphy, marine sediments, diagenesis 

Copy held: University of Waikato GC399.N35 1990 

Naish, T.R., Nelson, C.S., & Hodder, A.P.W. (1993). Evolution of Holocene sedimentary 

bentonite in a shallow- marine embayment, Firth of Thames, New Zealand. Marine 

Geology 109, 267-278. 

Subject: Sedimentation, geology. Abstract: “Firth of Thames, northern North Island, New 

Zealand, is a low-wave energy, shallow (

190 

reflecting the hydration of glass and the formation of smectite, respectively. The model 

indicates the half-life for volcanic glass in the Firth of Thames is only 1500 years. 

Despite the fact that these smectite-rich muds have not evolved from the alteration of primary 

pyroclastic deposits, but rather from detrital reworked volcanic glass, we classify them 

sedimentary bentonite. We suggest the mode of emplacement of the volcanic material is 

irrelevant to the name bentonite. Moreover, in contrast to many other studies of bentonite 

deposits, the Firth of Thames occurrence is different because it is thick (>5 m), has a young 

(Holocene) age, and is forming in a shallow-marine setting (< 30 m) from the rapid alteration of 

glass to smectite, within only a few 1000 years. The abundance of detrital silicic volcanic glass 

supplied from the Hauraki Lowland catchment, currently up to 65% by weight of total sediment 

input, determines the abundance of smectite in the Firth of Thames.” 

Note: core stratigraphy of two offshore and two nearshore cores from the Firth of Thames is 

detailed and compositional data for some catchment river sediments are presented. 

Keywords: Holocene, marine sediments, diagenesis, detrital volcanic glass, smectite, bentonite 

Copy held: EQ (reprint) 

Nature Conservation Council. (1984). Strategies for the management of mangrove forests in 

New Zealand. Unpublished discussion document September 1984, Nature Conservation 

Council, Wellington, NZ. 

Subject: Mangroves, policy and planning 

Keywords: mangrove requirements, limiting factors, ecological significance, threats, protection 

Copy held: EQ (BB), University of Waikato QH541.5S245 1984 (NZ Collection, outsize). 

Neale, H. (1996). Firth of Thames. In Scott, D.A. (Ed.), A directory of wetlands in New Zealand 

Compiled by Cromarty for the Department of Conservation New Zealand, International 

Waterfowl and Wetlands Research Bureau (IWRB), Ramsar Convention Bureau. 

Wellington: Department of Conservation. 

Subject: Wetlands. A comprehensive summary of the Firth of Thames wetland areas, which, in 

addition to descriptions of physical and ecological features, describes conservation measures 

(existing and proposed) and potential changes in land use. 

Keywords: Firth of Thames, Ramsar Convention, coastal intertidal wetland, waterfowl, 

threatened species 

Copy held: EQ 

New Zealand Wildlife Service. (1981). Habitat Register. Page 89, Firth of Thames sheet. 

Hamilton, NZ: New Zealand Wildlife Service, Department of Internal Affairs. 

NIWA. (2002). Factors related to the sustainability of shellfish aquaculture operations in the 

Firth of Thames: A preliminary analysis.NIWA Client report prepared for ARC and 

EW, February 2002. 

Norris, K. & Johnstone, I. (1998). The functional response of oystercatchers (Haematopus 

ostralegus) searching for cockles (Cerastoderma edule) by touch. Journal of Animal 

Ecology, 67(3), 329-246. 



Ogle, C.C. (1981). Vascular plants on land of the Miranda Naturalists’ Trust, Miranda. 

Auckland Botanical Society Newsletter 39. 


Oldman, J.W. & Senior, A.K. (2000). Wilson’s Bay marine farm dispersal modelling. Client 

report: EVW01218, NIWA. 

Subject: Marine farming. Numerical modelling of the Firth of Thames was undertaken in view 

of future development of marine farms in the Firth of Thames. Hydrodynamic modelling 


191 

accounts for water movement at various depths generated by tides, winds and density gradients 

from temperature variation. A plume dispersal model was used to predict the 3-dimensional 

movement and spread of a conservative tracer released from Wilson’s Bay. 

Keywords: migration of water, numerical modelling, hydrodynamic model, plume dispersion 

model, plume migration, water circulation, Firth of Thames 

Copy held: EQ, EW, NIWA 

O’Neil, P. (1991). An economic approach to the problem of pollution in the Piako/Waitoa 

catchment by dairy shed waste. 


Copy held: University of Waikato HD2195.5.A1M187 no.2 (NZ Collection, outsize) 

O’Regan, P., Morad, M., & Chalmers, A.I. (n.d.). Digital analysis of shoreline change: a 

preliminary case study of Te Puru in the Coromandel Peninsula. 


Copy held: University of Waikato LG741.5W3R4 no.3510 (in storage) 

O’Regan, P., & Chalmers, L. (1993). Shoreline change analysis using digital mapping 

techniques: Report to Environment Waikato. Hamilton, NZ: Department of Geography, 

University of Waikato. 


Copy held: University of Waikato GB458.55.068 1993 (NZ Collection, outsize) 

Ornithological Society of New Zealand. (1957-1962). Annual locality reports: Miranda Coast, 

Firth of Thames. Notornis 7(3), 88-90; Notornis 7(7), 201-202; Notornis 7(7), 216-219; 

Notornis 9(3), 83-84, 93-94; Notornis 9(7), 255-256; Notornis 10(3), 128-130; Notornis 

10(7), 346-347. 

Subject: Birds. Reports include species lists of birds sighted at Miranda, Firth of Thames. 

Keywords: Firth of Thames, Miranda, bird sightings 

Copy held: EQ 

Park, G. (1995). Nga Uruora (the groves of life): Ecology and history in a New Zealand 

landscape.Chap. 1[1] The immense trees of Ooahaouragee. Wellington, NZ: Victoria 

University Press. 

Subject: History, ecology 

Keywords: Cook and Banks, Waihou, Maori settlements, kahikatea forests, flax, Hauraki Plains, 

Oruarangi, Maori culture, timber harvesting, ecological modification, restoration 


Park, P. V. (1980). Comments on a remnant of Kahikatea floodplain forest, Waihou River, 

Hauraki Plains. Wellington, NZ: Botany Division, DSIR. 


Keywords: Kahikatea floodplain forest, Waihou River, Hauraki Plains 


Parliamentary Commissioner for the Environment. (1998). Kaitiakitanga and local 

government: Tangata whenua participation in environmental management. Wellington, 

NZ: Author. 133pp. 


Keywords: environmental management 

Copy held: EQ 


192 

Passioura, J.B., et al. (1992). Mangroves may salinize their soil and in so doing limit their 

transpiration rate. Functional Ecology 6, 476-481. 


Paul L.J. (1968). Some seasonal water temperature patterns in the Hauraki Gulf. New Zealand 

Journal of Marine and Freshwater Research 2, 535-558. 


Keywords: Fisheries, sample stations, Hauraki Gulf, SW Firth of Thames 


Paul L.J. (1974). Hauraki Gulf snapper fishery, 1972 and 1973: Some evidence for a declining 

catch-rate. New Zealand Journal of Marine and Freshwater Research 8(4), 569-587. 

Subject: Fish 

Keywords: snapper, Hauraki Gulf, commercial fishing, overcatch rates, fishery 

Copy held: EQ (NK), University of Waikato 

Paul, L.J. (1976). A study on age, growth and population structure of the snapper (C. auratus) 

in the Hauraki Gulf. Wellington, New Zealand: Fisheries Research Division, MAF. 

Subject: Fish 

Copy held: University of Waikato SH318.5.A1N43 no.13 (NZ Collection, outsize). 

Penny, S.F., Donoghue, M.F., & Aspell, A. (1987). Heavy metals in sediments of four rivers 

draining into Tikapa Moana (Firth of Thames). Report to the Environmental Council, 

Auckland. Prepared for Peninsula Watchdog. 

Subject: Pollution, sedimentation. Sediment samples were collected from four different rivers 

(Waiomu, Kauaeranga, Waihou and Piako) draining into the Firth of Thames. The latter two 

rivers drain swamp and agricultural land and the former two drain catchments with 

predominantly secondary growth native forest and some plantation forests (Pinus radiata). 

Agricultural, industrial and mining waste has been (and is being) discharged into these rivers at 

various points within the catchments. Heavy metal levels in the Hauraki river mouths were 

higher than in some other rural areas due to a wide variety of inputs, including natural sources. 

It was not possible to estimate the relative contribution (of heavy metals in the sediments) of 

past mining in the catchments. Levels of zinc and cadmium in the sediments were cause for 

concern, and the report cautioned against any increase in the levels of these heavy metals. 

Keywords: sediment analysis, heavy metals, impacts of heavy metals on wildlife 

Copy held: EQ, DoC 

Phillips, C. (2000). Waihou journeys: The archaeology of 400 years of Maori settlement. 

Auckland: Auckland University Press. 

Subject: History. Caroline Phillips traces the story of the Waihou from the time of the first 

voyaging ancestors. The book traces cultural change and development. Settlement in the 

Waihou area is painstakingly reconstructed, examined and explained 

Keywords: Maori history and settlement, Waihou, Hauraki, archaeology 

Copy held: EQ (RB) 

Phillips, F.L. (1989). Landmarks of Tainui .A geographical record of Tainui traditional history, 

Volume 2. Otorohanga, NZ: Tohu Publishers. 


Copy held: University of Waikato GN492T13P472 1995 (NZ Collection, outsize). 

Pickrill, R.A., & Mitchell J.S. (1979). Ocean wave characteristics around New Zealand. New 




193 

Pierce, R. J. (1999). Regional patterns of migration in the Banded Dotterel (Charadrius 

bicinctus bicinctus). Notornis 46, 101-122. 

Piersma, T., Hoekstra, R.., Dekinga, A., Koolhaas, A., Wolf, P., Battley, P., & 

Wiersma, P.(1993). Scale and intensity of intertidal habitat use by knots Calidris 

canutus in the western Wadden Sea in relation to food, friends and foes. 

Netherlands Journal for Sea Research 31, 331-357. 

Piersma, T., van Aelst, R., Kurk, K., Berkhoudt, H., & Maas, L.R.M. (1998). A new 

pressure sensory mechanism for prey detection in birds: The use of principles of 

seabed dynamics? Proceedings of the Royal Society of London, B 265, 1377- 

1383. 

Pillans, B. (1986). A late Quarternary uplift map for North Island, New Zealand. Royal Society 

of New Zealand Bulletin 24, 409-417. 

Pishief, P.J. (1974). Mangroves in New Zealand: A preliminary bibliography. Wellington, New 

Zealand: New Zealand Oceanographic Institute. 


Copy held: University of Waikato GC1.N4 no.63 (in storage, reference only) 

Pocknall, D.T., Gregory, M.R., & Greig, D.A. (1989). Palynology of core 80/20 and its 

implications for understanding Holocene sea level changes in the Firth of Thames, New 

Zealand. Journal of the Royal Society of New Zealand 19(2), 171-179. 


Pridmore, R.D., Thrush, S.F., Cummings, V.J., & Hewitt, J.E. (1992). Effect of the 

organochloride pesticide technical chlordane on intertidal macrofauna. Marine 

Pollution Bulletin 24, 98-102. 


Keywords: Benthic fauna, organochloride pesticide, chlordane, intertidal macrofauna 

Copy held: EQ 

Pridmore, R.D., Thrush, S.F., Hewitt, J.E., and Roper, D.S. (1990). Macrobenthic community 

composition of six intertidal sandflats in Manukau Harbour, New Zealand. New 



Keywords: invertebrates, intertidal ecology, macrobenthic community structure, population 

densities, sand flats 

Copy held: EQ 

Proctor, R., & Greig, M.J.N. (1989). A numerical model investigation of the residual 

circulation in Hauraki Gulf, New Zealand. New Zealand Journal of Marine and 

Freshwater Research 23, 421-442. 

Subject: Oceanography. Shows gyre in lower Gulf. 

Keywords: Hauraki Gulf, modelling, residual circulation, tides, winds, oceanic inflows 

Copy held: EQ 

Rapley, S.F. (1973). Flood protection and farming in the Hauraki Plains Country1860 -1973. 

Unpublished master’s dissertation, Department of Geology, University of Auckland. 

Subject: Flood control, history, Hauraki Plains 


Read, G., & Handley, S. (2004). New alien mudworm now becoming a pest in longline 

mussels. Water & Atmosphere 12(3), 30-31. 


194 

Reid, B. (1969). Mussel survey: Hauraki Gulf and Firth of Thames 1958. New Zealand: Marine 

Department, Fisheries Technical Report No.34, 24pp. 


Keywords: benthic fauna, mussel survey, Firth of Thames, spawning season, New Brighton, 

Thames, commercial dredging, depletion of stocks 

Rennie, H.G. (2000). Coastal fisheries and marine planning in transition. In P.A. Memon & H. 

Perkins, (Eds.), Environmental planning and management in New Zealand. NZ: 

Dunmore Press, Ltd. 


Keywords: marine commons, integrated coastal management, single sector planning 

Copy held: EQ, University of Waikato 

Riegen, A.C. (1999). Movements of banded arctic waders to and from New Zealand. Notornis 

46, 123-142. 


Keywords: Arctic waders, lesser knot, bar-tailed godwit, turnstone, migration, recoveries 

Copy held: EQ 

Riegen, A.C., & Dowding, J.E. (2003). The wrybill Anarhynchus frontalis: a brief 

review of status, threats and work in progress. Wader Study Group Bulletin 100, 

20-24. 

Robertson, H.A. (Ed.). (1999). Wader studies in New Zealand. Notornis 46(1), 1-242. 

Subject: Birds, waders 

Rödsjö, L. (1995). Magnetic sidescan sonar survey of the Firth of Thames. Unpublished 

master’s dissertation, University of Waikato. Hamilton, New Zealand. 98pp. 

Subject: Sedimentation, geology. Abstract: “Surficial sediments and subsurface geology of the 

Firth of Thames were investigated based on sidescan sonar and magnetometer surveying. 

Sidescan sonar survey carried out in 1990 by the Marine Geosciences Group (University of 

Waikato) to refine existing data on the surficial sediments within the Firth of Thames shown on 

maps produced by Carter & Eade (1982), Naish (1990) & van Leeuwe (1991). Interpretation of 

the sonographic patterns identified showed: 

i) A large central lobe of relatively fine gravel, interpreted as being calc-gravel 

ii) Coarse delta fan gravels off the eastern & western coasts of the Firth 

iii) An area of bedrock through a veneer of mud on the eastern side of the Firth of Thames, a 

small area of what may be mussel or oyster beds on the western side of the Firth 

iv) An area of mainly sandy bottom sediments off the western coast of the First (between the 

landward gravels & seaward muds) 

v) Extensive areas of muds, especially toward the south of the survey area….” 

Keywords: marine sediments, Firth of Thames, deposition, geomagnetism 

Note: summary and conclusion of interest, also sea floor map of Firth of Thames, identifying 

faults and different sediments and interpretation of these. 

Copy held: University of Waikato GC399.R64 1995 

Rödsjö, L. (1995). Storm damage assessment of the Thames – Te Aroha area following the 

storm of April 1981. Palmerston North, NZ: Soil Conservation Centre. 

Subject: Flood control 

Roper, D.S., Thrush, S.F., & Smith, D.G. (1988). The influence of runoff on intertidal mudflat 

benthic communities. Marine Environmental Research 26, 1-18. 


195 


Keywords: benthic fauna, runoff, intertidal mudflats 

Saintilan, N. (1998). Relationships between height and girth of mangroves and soil-water 

conditions in the Mary and Hawkesbury River estuaries, eastern Australia. Australian 

Journal of Ecology 23, 322-328. 


Keywords: mangrove zonation, soil-water salinity, distance from mouth, ecology 

Copy held: EQ 

Salter, R.T., Crippen, T.T., & Noble, K.E. (1981). Storm damage assessment of the Thames - 

Te Aroha area following the storm of April 1981. Palmerston North, NZ: Soil 

Conservation Centre. 


Copy held: University of Waikato S625.N45P976 no.1 (NZ collection, outsize). 

Salter, R.T., Crippen, T.T., & Noble, K.E. (n.d.). Extraction of lithium from the Firth of 

Thames, New Zealand 


Keywords: Firth of Thames, lithium 

Copy held: Soil Conservation Centre, Palmerston North, University of Waikato LG741.5.W3R4 

no.4140 

Sandler, W. (1999). The migratory birds of Miranda:In their element, an ecological study of 

some aspects of a vulnerable environment. Unpublished report, Miranda Naturalists’ 

Trust. Auckland. 

Subject: Benthic ecology, birds. Some very relevant material, with observations on behavioural 

habits of benthic species and communities. Carried out benthic invertebrate survey of a mudflat 

plot 

Copy held: EQ 

Schofield, J.C. (1960a). Sealevel fluctuations during the last 4000 years. Nature 185(4716), 

836. 


Schofield, J.C. (1960b). Sealevel fluctuations during the last 4000 years as recorded by a 

Chenier plain, Firth of Thames, New Zealand. New Zealand Journal of Geology and 

Geophysics 3(3), 467-485. 

Subject: Geology, oceanography. Schofield studied the Miranda Chenier plain. He postulates 

that approx. 3,900 yr BP the sea level was 2.1 m above the present level. 

Keywords: Holocene sediments, constructional landforms, marsh clay, Waitakaruru, 

Whakatiwai, morphological detail, sea level interpretation, foreshore sequence 

Copy held: EQ 

Schofield, J.C. (1973). Post-glacial sea levels of Northland and Auckland. New Zealand Journal 

of Geology and Geophysics 16, 359-366. 

Subject: Geology & oceanography. The sea level was 2-2.1 m above its present level approx. 

3,900 yrs BP (Schofield 1960). This is evident from beach deposits at least 270 km northward 

from the Miranda area. 

Sharples, J., & Greig, M.J.N. (1997). Tidal currents, mean flows, and upwelling on the northeast 

shelf of New Zealand. New Zealand Journal of Marine and Freshwater Research 

32, 215-231. 



196 

Keywords: north-east shelf, East Auckland Current, internal tide 


Sibson, R.B. (1945). Some observations on South Island pied oystercatchers in Auckland. New 

Zealand Bird Notes 1(9), 107-109. 

Subject: Birds. Site specific counts of SIPO, and seasonal differences, including Firth of 

Thames. 

Keywords: South Island pied oystercatchers, Auckland, Firth of Thames, census, 

Copy held: EQ 

Sibson, R.B. (1948). Charadrius leschenaulti at Miranda. New Zealand Bird Notes 3(2),51. 

Subject: Birds. Detailed descriptions of a single specimen of Geoffrey’s sandplover 

(Charadrius leschenaulti), also known as the large sand dotterel, which was observed over 

several months of the summer at Miranda. 

Keywords: sand dotterel, Charadrius leschenaulti, Miranda. 

Copy held: EQ 

Sibson, R.B. (1956). Asiatic black-tailed godwits in the Firth of Thames. Notornis 7(2), 58-59. 

Two black-tailed godwits (Limosa limosa melanuroides) spent the summer of 1955/56 

at Miranda. This was the second instance of this species being recorded in New 

Zealand. 


Keywords: black-tailed godwits, Limosa limosa melanuroides, Miranda 

Copy held: EQ 

Sibson, R.B. (1966). Increasing numbers of South Island pied oystercatchers visiting northern 

New Zealand. Notornis 13, 94-7. 


Keywords: South Island pied oystercatchers 

Sibson, R.B. (1978). The Firth of Thames. New Zealand Environment 21, 4-7. 


Sibson, R.B., & Edgar, A.T. (1962). Little terns in the Firth of Thames. Notornis 10(2), 91-92. 

Subject: Birds. Short note providing conclusive evidence that the little tern (S. albifrons) is a 

migratory tern, which spends its non-breeding season in New Zealand. 

Keywords: Little Tern, S. albifrons, non-breeding flocks 

Copy held: EQ 

Sibson, R.B. & McKenzie, H. R. (1944). Some observations on stilts in the Firth of Thames. 

New Zealand Bird Notes 1(6), 51-57. 

Subject: Birds. Sibson and Mckenzie visited the west coast of the Firth of Thames at more or 

less monthly intervals from July 1941 until October 1942. All site visits coincided with the 

rising tide, in order to minimise errors. Observations were made on habitat use, feeding and 

breeding of stilts. The paper contains interesting descriptions of the Miranda-Kaiaua Coast, its 

vegetation and the waders that use the coastal habitat. 

Keywords: Miranda-Kaiaua coast, stilts, seasonal habitat use, feeding, breeding, waders 

Copy held: EQ 

Sibson, R.B., & McKenzie, H.R. (1960). Broad-billed sandpiper in the Firth of Thames: A new 

bird for New Zealand. Notornis 8(8), 233-235. 


197 

Subject: Birds. Record of occasions on which a broad-billed sandpiper was seen at Miranda. 

This sighting was thought to be a first for New Zealand. 

Keywords: broad-billed sandpiper, Limicola falcinellus siberica, Miranda, comparisons 

Copy held: EQ 

Skinner, D.N.B. (1986). Neogene volcanism of the Hauraki Volcanic Region. In Late 

Cenozoic Volcanism in New Zealand, Royal Society of New Zealand Bulletin 23. 


Smith, A.M. & Nelson, C.S. (1994). Calcification rates of rapidly colonising bryozoans in 

Hauraki Gulf, northern New Zealand. New Zealand Journal of Marine and Freshwater 

Research 28, 227-30. 


Keywords: bryozoa, calcification rate, carbonate sediments, sedimentation rate, Hauraki Gulf 

Copy held: University of Waikato LG741.5.W3R4 no.2767 (in storage); EQ (abstract) 

Smith, D.H. (1984). Waihou Valley Scheme: The interim Hikutaia Cut study report. Hauraki 

Catchment Board. 


Copy held: Environment Waikato, Hauraki District Council 

Smith, P.J., Holdsworth, J., Anderson, C., Hine, P.M., Allen, D., Gibbs, W., McKenzie, L., 

Taylor, P.R., Blackwell, R.H., & Williamson, S.H. (1996). Pilchard deaths in New 

Zealand, 1995. New Zealand Fisheries Data Report No.70 (ISSN 0113-2288). 

Wellington, NZ: NIWA. 

Subject: Fish 

Keywords: marine fish kills, herpes viruses, disruption to gill function 


Stanley, B. (2001). A bibliography of plant lists and vegetation surveys for the Auckland 

Conservancy by Ecological District. Auckland, NZ: Department of Conservation. 


Keywords: Hunua Ecological District 

Copy held: EQ, DoC 

Stanley, R. (1998). Auckland Threatened Plant Strategy. NZ: Department of Conservation. 


Keywords: conservation 

Copy held: EQ 

Stanley, R. (1999). Action Plan for the mistletoe at Miranda 1999-2003. Unpublished report for 

the Department of Conservation, Auckland. 


Keywords: Ileostylus micranthus, Miranda 

Copy held: EQ 

Stoffers, P., Glasby, G.P., Pluger, W.L., & Walter, P. (1983). Reconnaissance survey of the 

mineralogy and geochemistry of some New Zealand lakes and near shore sediments. 

New Zealand Journal of Marine and Freshwater Research 17, 461-480. 


Keywords: levels of copper, zinc & lead in Thames Estuary, anthropogenic influences 


198 

Strahan, D.C. (1997). The plant ecology of Miranda wetland: Restoration options. 

Unpublished master’s dissertation. University of Waikato, Hamilton, NZ. 


Keywords: Carex divis, wetland restoration, vegetation communities, environmental factors, 

habitat boundaries, revegetation, groundwater, soil analysis, grazing, invasive weeds, soil 

nitrogen, elevation, salinity, hydrology, herbicides, Miranda species list 

Copy held: Waikato University 

Strahan, J. (1992). Allocation of coastal resources to marine farming: a case study of mussel 

farming on the Coromandel Peninsula. Unpublished dissertation, University of 

Waikato, Hamilton, NZ. 


Copy held: University of Waikato SH372.52.N45S75 1992 

Stephens, S. (2003). Ecological sustainability assessment for Firth of Thames aquaculture: 

Task 1 – Hydrodynamic Modelling. NIWA Client Report: 2003-113, July 2003. 

Copy held: Western Firth Consortium, Auckland Regional Council, Environment Waikato 

Sukeforth, C. (2002). An investigation into diurnal variations in eel abundance at Miranda 

Stream, Spring 2002, Firth of Thames. Unpublished directed research project, EcoQuest 

Education Foundation, New Zealand. 

Sutherland, R.D. (1998). Marine farming sustainability study of the west coast Coromandel 

coastline. Part 1.A report prepared in support of ‘A variation to the Regional Coastal 

Plan’ for The PALMS Ltd, Blenheim, in association with Davidson Consultants, 

Nelson, November 1998. 

Subject: Policy and planning, marine farming 

Keywords: Mussel farming, Hauraki Gulf, Waikato Regional Coastal Plan, Coromandel 

Copy held: EQ 

Thames Valley United Council. (1985). An issues report for the Thames Valley region. 

Thames Valley United Council. 


Copy held: University of Waikato HT395.N42T44T5 1985 (NZ collection, outsize). 

Thompson, D. (1998). Heavy metals in shorebirds from the Auckland Region. NIWA Report, 

WG98/24, prepared for the Auckland Regional Council. 


Keywords: toxicity, mercury, lead, cadmium, heavy metals 

Copy held: EQ, ARC 

Thomson, P. (2000). Mapping of Spartina in the Firth of Thames. Unpublished report to the 

Department of Conservation, Hamilton. 


Keywords: Spartina, Waitakaruru, Waihou, mangroves 

Copy held: EQ 

Thrush, S.F., Hewitt, J.E., Cummings, V.J., & Dayton, P.K. (1995). The impact of habitat 

disturbance by scallop dredging on marine benthic communities: What can be predicted 

from the results of experiments? Marine Ecology Progress Series 129, 141-150. 



199 

Keywords: dredge disturbance, benthic habitat, recolonisation 


Todd, T.W. (1968). Dynamic diversion: Influence of longshore current-tidal flow interaction on 

Chenier and barrier island Plains. Journal of Sedimentary Petrology 38(8), 734-746. 

Subject: Oceanography, geology 

Keywords: post-Pleistocene sedimentation, shell-sand ridges, shoreline, long-shore currents 

Copy held: EQ 

Tye, R.E. (1974). Hauraki Plains story. Paeroa, NZ: Thames Valley News, Ltd. 183 pp. 

Subject: History, flood control 

Keywords: land drainage, river control, Waihou, Ohinemuri, Piako, Waitakaruru, Orongo, 

Netherton, Ngatea (Orchard), Pipiroa, colonial history, early timber & dairy industries 

Copy held: Hauraki District Council, Jocelyn Lane 

van Leeuwe, C.M. (1991). Transport of suspended sediments in the southern part of the Firth 

of Thames. Unpublished master’s dissertation, University of Waikato. Hamilton, New 

Zealand. 269pp. 

Abstract: “... Main source of the mud (of abundant mudflats along the southern shore of the 

Firth of Thames) is the Waihou River ...additional inputs from Piako and Kauaeranga rivers and 

the Waitakaruru river to the west. This study investigated the hydrodynamics of the first. 

Current velocity, temperatures and salinity were measured, and water and bottom samples 

collected to better understand the sediment transport in the southern Firth of Thames (bottom 

samples were analysed for texture, geomechanical properties and mineralogy). A big difference 

was found between the eastern and western sides of the Firth. Salinity in the eastern part was 

very low, due to the inflow of fresh water. Sediment plumes coming out of the Waihou River 

caused much higher concentrations of suspended sediment along the eastern margin. 

Several mechanisms prevent the escape of suspended material from the southern Firth: 

1) Estuarine circulation near the Waihou River mouth causes a flood dominance of the tidal 

current near the bottom, preventing escape of heavier particles near the bottom. 

2) Fine particles near the surface could escape northward, but flocculation of these particles 

enhances their settling velocities, so they still tend to get trapped by the estuarine circulation. 

3) The predicted pattern of residual tidal currents suggests a partial return of suspended particles 

in the Firth. 

Suspended material that escapes the estuary will partly be transported in northerly direction, 

while some will be transported to the west side of the Firth of Thames, by the north-west 

direction of the ebb current. This portion may eventually return to the southern Firth of 

Thames, as the residual current along the west coast has a southward direction. ....” 

(Note: extensive mapping of sediments of the Firth of Thames. Reference to the bathymetry of 

the Firth: Marine chart NZ533, onshore geology: Geological Map of NZ 1978. “Firth of Thames 

is an infilling basin: Firth of Thames is subsiding 0.1mm/yr; sedimentation 1.8-2.0 mm/yr 

(inshore), 0.8-1.0 mm/yr (centre of Firth).” 


Keywords: marine sediments, sediment transport, suspended sediments, marine circulation 

Copy held: EQ, University of Waikato GC399.V30 (36?) 1991 

Vant, B. (1999). Sources of the nitrogen and phosphorus in several major rivers in the Waikato 

Region. Environmental Waikato Technical Report 1999/10. 


Keywords: Hauraki River system, plant nutrients, river flow, point sources, background sources, 

diffuse sources, agriculture, stocking rate, Piako, Waihou 


200 

Copy held: EQ, Environment Waikato 

Van Roon, M.R. and S.J. Knight. (2003). Ecological Cycles as a basis for decision making. 

Oxford University Press, Melbourne. 

Van Roon, M.R. and S.J. Knight. (2001). Towards integrated catchment management, 

Whaingaroa, New Zealand. Water Science and Technology, 43(9), 197-202. 

Van Rossem, J. (1990). A review of surface water quality issues in the Piako/Waitoa 

catchment. Waikato Regional Council, Hamilton. Draft. 

Subject: Policy and planning, Pollution 



van Voorthuysen, R., & Strahan, J. (1991). Marine Farming, Firth of Thames: An assessment 

of the potential economic and social effects of 14 proposed marine farms. Hamilton, 

New Zealand: Waikato Regional Council. 

Due to closure of the innner Hauraki Gulf to marine farming, fourteen applications for marine 

farming (covering a total of 372 ha) were lodged for the area between Wilson Bay and 

Waikawau on the Thames Coast. This report documents the likely social and economic effects 

of the applications, should they be granted. Details are provided for the effects of establishment 

and operation of a theoretical unit of a 25 ha mussel farm. 


Copy held: EQ 

Veitch, C.R. (1978). Waders of the Manukau Harbour and the Firth of Thames. Notornis 25(1), 

1-24. 


Copy held: DoC, Waikato Conservancy, University of Waikato. 

Veitch, C.R. (1999). Annual cycle of waders at the Firth of Thames. Notornis 46, 71-78. 


Keywords: waders, annual cycle, Firth of Thames 

Copy held: EQ 

Veitch, C.R., & Habraken, A. (1999). Waders of the Manukau Harbour and Firth of Thames. 

Notornis 46, 45 – 70. 

Vooren, C.M. & Coombs, R.F. (1977). Variations in growth, mortality and population density 

of snapper (C.auratus) in the Hauraki Gulf. Wellington, New Zealand: Fisheries 

Research Division, MAF. 

Subject: Fish 

Copy held: University of Waikato (SH318.5.A1N43 no.14 (NZ Collection, outsize) 

Walton, G. (1995). Taming the Waihou: the story of the Waihou Valley Catchment flood 

protection and erosion control scheme. Hamilton, NZ: Waikato Regional Council. 

Subject: Flood control, history 

Copy held: University of Waikato (TC 522.6.W28W3 1995 (NZ Collection, outsize). 

Ward, J., & Snelder, T. (1997). Environmental indicators: Potential coastal and estuarine 

indicators: A review of current research data: Signposts for sustainability. Lincoln 

Environmental, Ministry for the Environment, Wellington. 



201 



Watson, S. (1996). Wilson’s Bay marine farm applications: assessment of environmental 

effects. (Final report). NIWA Consultancy Report SAN 300. Hamilton, N.Z. 


Keywords: community consultation, biodeposition, seabed accumulation of mussels & shells, 

economic impacts, waste production, land-based facilities, anchoring systems 

Copy held: EQ 

Whaley, K.J., Clarkson, B.D., & Leathwick, J.R. (1995). Assessment of the criteria used to 

determine ‘significance’ of natural areas in relation to Section 6(c) of the Resource 

Managment Act (1991). Unpublished Landcare Research contract report no. LC 

9596/021, Manaaki Whenua - Landcare Research, Hamilton. 

Subject: Policy and planning. This report shows how maps and statistics derived from 

Leathwick et al., (1995) can be used in preliminary assessment of the significance of indigenous 

vegetation remnants. It also reviews the assessment methodologies available for determining 

significance of indigenous vegetation or habitat where a field inspection is required. 

Keywords: significant indigenous vegetation 

Copy held: Landcare, Hamilton 

Willis, G. (September, 2004).Hauraki Gulf Forum: A review of performance 2000-2004 

(Interim Report. Enfocus Ltd., Private Bag MBE M251, Auckland 

Woodley, K. (2000). Mistletoe planting project. Miranda Naturalists’ Trust News 38, p.6 


Keywords: mistletoe, Miranda 

Copy held: EQ 

Woodroffe, C.D. (1982). Litter production and decomposition in the New Zealand mangroves 

(Avicennia marina var. resinifera). New Zealand Journal of Marine and Freshwater 

Research 16(1), 179-188. 



Woodroffe, C.D., Curtis, R.J., & McLean, R.F. (1983). Development of a Chenier plain, Firth 

of Thames, New Zealand. Marine Geology 53, 1-22. 

Subject: Geology, sedimentation 

Keywords: long-shore drift, coastal plain, littoral sediments, fine-grained river sediments, storm 

crest deposition, Mactra ovata, embayed tidal flat sediments, regressive coastal phase, stable 

sea levels, landward and southward migrations 

Copy held: EQ 

Worley Consultants Ltd. (1996). Marine farming study west coast of the Coromandel 

Peninsula, Hamilton, New Zealand. Report to Waikato Regional Council, Worley 

Consultants Ltd., PO Box 434, Hamilton, New Zealand. 


Keywords: aquaculture, Firth of Thames, Coromandel, mussels 

Copy held: EQ, NIWA 

Worley Consultants Ltd. (1997). Applications for resource consent: Statement of supporting 

information and assessment of environmental effects [regarding proposed gravel loading 


202 

jetty in the Waihou River mouth]. Worley Consultants, Ltd., PO Box 434, Hamilton, 

New Zealand 

(Oct. 1997). Report to H.G. Leach & Co. (Paeroa) 


Copy held: H.G. Leach 

Young, B.M. (1993). The mangrove as a geomorphic agent: an investigation of accretion rates 

and mangrove stand physiognomy, at the Piako River Mouth, Hauraki Plains, New 

Zealand. University of Auckland, NZ. 


Keywords: mangrove physiognomy, accretion, Piako, Firth of Thames 


Young, B.M., & Harvey, L.E. (1996). A Spatial Analysis of the Relationship Between 

Mangrove (Avicennia marina var. australasica) Physiognomy and Sediment Accretion 

in the Hauraki Plains, New Zealand. Estuarine, Coastal and Shelf Science 42, 231-246. 

Subject: Mangroves. Abstract: “The relationship between mangrove (Avicennia marina var. 

australasica) physiognomy and forest bed accretion was quantified using experimental and field 

measurements at the Piako River mouth, Firth of Thames, New Zealand. Sediment accretion 

under six densities of artificial pneumatophores was monitored for 13 weeks in an experimental 

plot, while accretion was simultaneously monitored for 5 months at 102 locations along two 

parallel 500 m transects. Experimental results demonstrated that accretion increases with 

pneumatophore density. This was supported by bivariate analyses of cumulative accretion and 

Avicennia marina srem density, basal area and pneumatophore density along the transects. Only 

the latter is significantly correlated with accretion. Geostatistical analysies showed that variation 

in sediment accretion occurs at the same spatial scale as pneumatophore density. Accretion and 

pneumatophore density are spatially autocorrelated over distances

203 

Zharikov, Y. & Skilleter, G.A. (2002). Sex-specific intertidal habitat use in 

subtropically wintering Bar-tailed Godwits. Canadian Journal of Zoology 80, 

1918-1929. 

Zwarts, L., & Blomert, A.M. (1992). Why knot Calidris canutus take medium-sized 

Macoma balthica when six prey species are available. Marine Ecology Progress Series 

83, 113-128. 

Location of documents: 

ARC: Auckland Regional Council, Auckland, New Zealand. 

BB: Held in the collection of Bill Brownell, 30 Pukekereru Lane, Kaiaua, RD 3, Pokeno, NZ 

Brian T. Coffey & Associates: P.O. Box 83, Whangamata 

DoC Waikato Conservancy, Hamilton; Hauraki Area Office, Thames; Waikato Area Office, Te 

Rapa; DoC Auckland Conservancy and Area Office, Auckland 

Environment Waikato, Waikato Regional Council, EW, Grey St., Hamilton East 

EQ: EcoQuest Education Foundation, East Coast Rd., Kaiaua, RD 3, Pokeno, NZ 

Miranda Shorebird Centre, R.D. 1, Pokeno 

NIWA: National Institute for Water and Atmospheric Research. Formerly, New Zealand 

Oceanographic Institute (NZOI). 

NK: Nigel Keeley, Cawthron Institute, Nelson, NZ 

RB: Ria Brejaart, EcoQuest Education Foundation. 

University of Auckland, Auckland, New Zealand. Library: www.auckland.ac.nz/lbr 

University of Waikato, Hamilton, New Zealand. In most instances these are in the library 

collections of the university and the call number may be included. Refer: www.waikato.ac.nz 

Western Firth Consortium, Coromandel, NZ (contacts Allan Bartrom and Campbell Barr)

MUDDY FEET - Auckland Regional Council

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