Kefs) in the Northwest Marine Region
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GEOSCIENCE AUSTRALIA Review of Ten Key Ecological Features (KEFs) in the Northwest Marine Region A report to the Department of the Environment, Water, Heritage and the Arts by Geoscience Australia I. Falkner, T. Whiteway, R. Przeslawski & A.D. Heap Record 2009/13 GeoCat # 68732 APPLYING GEOSCIENCE TO AUSTRALIA’S MOST IMPORTANT CHALLENGES Review of Ten Key Ecological Features (KEFs) in the Northwest Marine Region A REPORT TO THE DEPARTMENT OF THE ENVIRONMENT, WATER, HERITAGE AND THE ARTS BY GEOSCIENCE AUSTRALIA GEOSCIENCE AUSTRALIA RECORD 2009/13 By Falkner, I. 1, Whiteway T. 1, Przeslawski R. 1 and Heap A.D. 1 1 Petroleum and Marine Division, Geoscience Australia, GPO Box 378, Canberra, ACT 2601 Department of Resources, Energy and Tourism Minister for Resources and Energy: The Hon. Martin Ferguson, AM MP Secretary: Mr John Pierce Geoscience Australia Chief Executive Officer: Dr Neil Williams PSM © Commonwealth of Australia, 2009 This work is copyright. Apart from any fair dealings for the purpose of study, research, criticism, or review, as permitted under the Copyright Act 1968, no part may be reproduced by any process without written permission. Copyright is the responsibility of the Chief Executive Officer, Geoscience Australia. Requests and enquiries should be directed to the Chief Executive Officer, Geoscience Australia, GPO Box 378 Canberra ACT 2601. Geoscience Australia has tried to make the information in this product as accurate as possible. However, it does not guarantee that the information is totally accurate or complete. Therefore, you should not solely rely on this information when making a commercial decision. ISSN 1448-2177 ISBN (print) 978-1-921498-66-4 ISBN (web) 978-1-921498-65-7 GeoCat # 68732 Bibliographic reference: Falkner, I., Whiteway, T., Przeslawski, R., Heap, A.D. 2009. Review of Ten Key Ecological Features (KEFs) in the North-west Marine Region. Geoscience Australia, Record 2009/13. Geoscience Australia, Canberra. 117pp. Table of Contents Record 2009/13 1 List of Figures vii List of Tables ix Executive summary x 1 Introduction 1 1.1 Aims of this study 1 1.2 Key Ecological Features in the North-west Marine Region 2 1.3 Seascapes 3 1.3.1 Characterisation of habitat and species diversity 3 1.3.2 National seascapes 5 1.4 The deep-sea environment 7 1.4.1 The physical environment of the deep-sea 8 1.4.2 Deep-sea biodiversity 9 1.4.3 Threats to the deep-sea environment 10 1.5 Regional background 11 1.5.1 Geology 11 1.5.2 Local oceanography 11 1.5.3 Provincial bioregions of the North-west Marine Region 12 1.5.4 Commercial and Industrial Development 13 2 Methods 14 2.1 Data collection and reporting 14 2.1.1 Biological data 14 2.1.2 Physical data 16 2.2 Seascapes analysis for the North-west Marine Region 17 2.3 Focal variety analysis 18 2.4 Seascape analysis for Glomar Shoals 19 2.5 Fish assemblages of Glomar Shoals area 21 2.6 Linking fish diversity to environmental variables at Glomar Shoals 22 iii 3 Results 24 3.1 Abyssal plains 24 3.1.1 The Argo Abyssal Plain 25 3.1.1.1 General description........................................................................................25 3.1.1.2 Physical data.................................................................................................. 26 3.1.1.3 Biological data............................................................................................... 27 3.1.1.4 Seascapes and focal variety analysis............................................................. 28 3.1.2 The Cuvier Abyssal Plain 30 3.1.2.1 General description........................................................................................30 3.1.2.2 Physical data.................................................................................................. 30 3.1.2.3 Biological data............................................................................................... 32 3.1.2.4 Seascapes and focal variety analysis............................................................. 32 3.2 Marginal Plateaus 34 3.2.1 Exmouth Plateau 34 3.2.1.1 General description........................................................................................34 3.2.1.2 Physical data.................................................................................................. 35 3.2.1.3 Biological data............................................................................................... 37 3.2.1.4 Seascapes and focal variety analysis............................................................. 39 3.2.2 Scott Plateau 41 3.2.2.1 General description........................................................................................41 3.2.2.2 Physical data.................................................................................................. 42 3.2.2.3 Biological data............................................................................................... 43 3.2.2.4 Seascapes and focal variety analysis............................................................. 44 3.3 Submarine canyons 46 3.3.1 Cape Range, Cloates and Mermaid Canyons 47 3.3.1.1 General description........................................................................................47 3.3.1.2 Physical data.................................................................................................. 47 3.3.1.3 Biological data............................................................................................... 49 3.3.1.4 Seascapes and focal variety analysis............................................................. 50 3.3.2 Bowers and Oates Canyons 52 3.3.2.1 Physical data.................................................................................................. 53 3.3.2.2 Biological data............................................................................................... 53 3.3.2.3 Seascapes and focal variety analysis............................................................. 53 3.4 Saddles 55 iv 3.4.1 Wallaby Saddle 55 3.4.1.1 Physical data.................................................................................................. 56 3.4.1.2 Biological data............................................................................................... 57 3.4.1.3 Seascapes and focal variety analysis............................................................. 57 3.5 Holocene coastline at the 125m isobath 59 3.5.1.1 General description........................................................................................59 3.5.1.2 Physical data.................................................................................................. 59 3.5.1.3 Biological data............................................................................................... 61 3.5.1.4 Seascapes and focal variety analysis............................................................. 63 3.6 Shoals 65 3.6.1 Glomar Shoals 65 3.6.1.1 General description........................................................................................65 3.6.1.2 Physical data.................................................................................................. 66 3.6.1.3 Biological data............................................................................................... 67 3.6.1.4 Seascapes and focal variety analysis............................................................. 68 3.7 Scott Reef 70 3.7.1 General description 70 3.7.2 Biological information for Scott Reef 71 3.7.3 Seascapes and focal variety analysis 71 3.8 Integration of biological data into seascapes 73 3.8.1 Seascapes excluding biological data 73 3.8.2 Seascapes including biological data 75 3.8.3 Comparison of seascapes with and without biological data 77 3.9 Statistical analysis of fish assemblage data at Glomar Shoals 78 3.9.1 Similarity of fish assemblages from Glomar Shoals area 78 3.9.2 Linking fish diversity to environmental variables at Glomar Shoals and surrounding area 79 3.9.3 Linking environmental variables to fish diversity at Glomar Shoals only 80 4 Discussion 82 4.1 Representativeness and uniqueness of KEFs 82 4.1.1 The Argo and Cuvier Abyssal Plains 82 4.1.2 The Exmouth and Scott Plateaus 83 4.1.3 The submarine canyons in the North-west Marine Region 84 4.1.4 The Wallaby Saddle 84 v 4.1.5 Scott Reef 84 4.1.6 The Holocene coastline 85 4.1.7 Glomar Shoals 85 4.2 Ecological significance of KEFs 86 4.2.1 Soft-sediment environments – abyssal plains, marginal plateaus & saddles 86 4.2.2 Submarine Canyons 89 4.2.3 Scott reef 91 4.2.4 The Holocene coastline 92 4.2.5 Glomar Shoals 93 4.3 Challenges 93 4.3.1 Limitations of seascape analysis 93 4.3.2 Paucity of robust biological datasets 94 4.3.3 Correlation of biological pattern to environmental properties 95 5 References 96 6 Acknowledgements 106 7 Appendix 107 vi List of Figures Figure 1.1. KEFs of the North-west Marine Region examined in this study. .................. 3 Figure 1.2. National seascape map for the off-shelf region of Australia.......................... 6 Figure 1.3. National seascapes for the on-shelf region of Australia................................. 7 Figure 1.4. Provincial bioregions of the North-west Marine Region. ............................ 13 Figure 2.1. Graphs of seascape versus abiotic factors.................................................... 18 Figure 2.2. Methodology for calculating the focal variety index ................................... 19 Figure 2.3. Biological samples covering Glomar Shoals and immediate surrounds...... 20 Figure 2.4. Shannon diversity indices interpolated as spatial