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Marine biodiversity stocktake of the Waikato region 2015

TR 2015/48
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Report: TR 2015/48

Author: Sietse Bouma

Abstract

Marine (including coastal) biodiversity is important for the healthy functioning of marine ecosystems, and for ecosystem productivity. Every organism plays a role in maintaining a healthy ecosystem, so an ecosystem with high biodiversity is generally more resilient to change. Protecting or maintaining biodiversity therefore helps to protect the health of our ecosystems. Biodiversity is also important for the provision of ecosystem services, which are the benefits that mankind receives or values from natural habitats. For marine ecosystems these include food provision, water filtration, nutrient regulation and storm protection. 

This report covers different ecological groups (benthic communities, estuarine and coastal vegetation, fish, birds and marine mammals) and four subtidal biogenic habitats that are known to be of specific importance for these ecological groups (rhodolith beds, shellfish beds, seagrass beds and sponge gardens). For each ecological group the report provides an inventory of completed surveys and information on the presence of particular species and/or habitats. The sections subsequently provide information on vulnerable life stages of species and the sensitivity of species and/or habitats to specific pressures. For each of the subtidal biogenic habitats a general description is provided followed by information on their known distribution in the Waikato Coastal Marine Area, their importance for biodiversity and pressures on these habitats.  

Marine biodiversity stocktake of the Waikato region 2015 - Volume 1: Reports and references [PDF, 5.7 MB]

Marine biodiversity stocktake of the Waikato region 2015 - Volume 2: Appendices [PDF, 24 MB]

Contents
  Acknowledgement i
1 Introduction 1
1.1 Background 1
1.2 Policy context 1
1.3 Project scope 2
1.4 Information sources 3
1.5 Maps 4
1.6 Accessibility of information 4
1.7 Structure of this report 5
2 Benthic communities 6
2.1 Protected, threatened or at risk species 6
2.2 Inventories and surveys 6
2.2.1 Coromandel harbours and estuaries 6
2.2.2 West coast river mouths and harbours 9
2.2.3 Offshore marine environment 10
2.3 Vulnerable life stages 13
2.4 Sensitivity to specific pressures 13
2.4.1 Sedimentation in the Waikato region 13
2.4.2 Sensitivity of soft sediment benthic communities to fine sediments 16
2.4.3 Sensitivity of rocky reef communities to sediment runoff 21
3 Estuarine and coastal vegetation 22
3.1 Protected, threatened or at risk species 22
3.2 Inventories and surveys 22
3.2.1 Estuarine vegetation 22
3.2.2 Coastal vegetation 24
3.2.3 Vegetation on offshore islands 25
3.3 Sensitivity to specific pressures 25
3.3.1 Sensitivity of estuarine vegetation to climate change 26
3.3.2 Vulnerability of estuarine vegetation to the invasion of saltwater paspalum 27
4 Fish 30
4.1 Protected, threatened or at risk species 30
4.2 Inventories and surveys 30
4.2.1 Demersal fishes Hauraki Gulf 30
4.2.2 Shallow rocky reef fishes Hauraki Gulf 31
4.2.3 Fish in the Waikato region’s harbours and estuaries 32
4.2.4 Shallow rocky reef fishes in the Waikato region 35
4.2.5 Diadromous fishes in the Waikato region 36
4.3 Vulnerable life stages 37
4.3.1 Coastal and marine fish species 37
4.3.2 Diadromous fish species 41
4.4 Sensitivity to specific pressures 45
4.4.1 Sensitivity to underwater noise 45
4.4.2 Sensitivity to sedimentation 46
5 Birds 47
5.1 Protected, threatened or at risk species 47
5.2 Inventories and surveys 47
5.2.1 Seabirds 48
5.2.2 Shorebirds 52
5.2.3 Wetland birds 57
5.3 Vulnerable life stages 58
5.4 Sensitivity to specific pressures 62
5.4.1 Sensitivity of birds to human disturbance 63
5.4.2 Sensitivity of wetland birds to habitat loss and predation 64
6 Marine mammals 66
6.1 Protected, threatened or at risk species 66
6.2 Inventories and surveys 66
6.2.1 Marine mammals in New Zealand waters 66
6.2.2 Marine mammals in the Hauraki Gulf 66
6.2.3 Marine mammals in the Firth of Thames 67
6.2.4 Common dolphins eastern side of the Coromandel Peninsula 67
6.2.5 Marine mammals west coast of the Waikato region 67
6.3 Vulnerability life stages 68
6.4 Sensitivity to specific pressures 68
6.4.1 Sensitivity to underwater noise 68
6.4.2 Sensitivity to human disturbance 71
6.4.3 Sensitivity of large whales to ship strike 73
7 Subtidal biogenic habitats 75
7.1 Rhodolith beds 76
7.1.1 General description 76
7.1.2 Known distribution 77
7.1.3 Importance for biodiversity 78
7.1.4 Pressures on rhodolith beds 79
7.2 Subtidal shellfish beds 80
7.2.1 Horse mussels 80
7.2.2 Dog cockles 83
7.2.3 Scallop beds 84
7.3 Subtidal seagrass 85
7.3.1 General description 85
7.3.2 Known distribution 85
7.3.3 Importance for biodiversity 86
7.3.4 Pressures on subtidal seagrass 87
7.4 Sponge gardens 87
7.4.1 General description 87
7.4.2 Known distribution 88
7.4.3 Importance for biodiversity 89
7.4.4 Pressures on sponge gardens 89
8 Discussion 90
  References 92