The South-west Marine Region: Ecosystems and Key Species Groups Department of the Environment and Water Resources Main authors: S McClatchie, J Middleton, C Pattiaratchi, D Currie, G Kendrick Contributing authors: J Baker, S Bryars, C Burton, R Campbell, N Caputi, G Collings, C Dixon, J Fromont, P Gill, D Gaughan, N Goldberg, S Goldsworthy, M Kangas, H Kemps, A Linnane, N Loneragan, S Mayfield, J McDonald, J McKenzie, L McLeay, M Morrice, L Nicholson, P Rogers, S Sorokin, J Stoddart, M Steer, C Surman, J Totterdell, D Trinder, L Twomey, P van Ruth, T Ward, G Westphalen, J Young 1 © Commonwealth of Australia 2006 This work is copyright. Apart from any use as permitted under the Copyright Act 1968, no part may be reproduced by any process without prior written permission from the Commonwealth, available from the Department of the Environment and Water Resources. Requests and inquiries concerning reproduction and rights should be addressed to: Assistant Secretary National Oceans Office Branch Department of the Environment and Water Resources Edgar Waite Building 203 Channel Highway KINGSTON TAS 7050 ISBN 9780642553815 The views and opinions expressed in this publication are those of the authors and do not necessarily reflect those of the Australian Government or the Minister for the Environment and Water Resources. While reasonable efforts have been made to ensure that the contents of this publication are factually correct, the Commonwealth does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication. 2 Contents Acknowledgments .................................................................................................................. 4 1 Executive summary...................................................................................... 5 1.1 Purpose, focus, and structure of the report............................................................ 5 1.2 Overview ................................................................................................................ 7 Part 1 - Ecosystems 2 Physical oceanography ...............................................................................10 2.1 Shark Bay to Esperance ...................................................................................... 10 2.2 Esperance to Robe .............................................................................................. 35 3 Ecological integration ..................................................................................68 3.1 Biodiversity........................................................................................................... 68 3.2 Food webs............................................................................................................ 84 3.3 Pelagic and benthic production............................................................................ 89 3.4 Seasonal cycles ................................................................................................... 92 3.5 Links to ocean circulation processes ................................................................. 105 References................................................................................................... 121 Part 2 - Key Species Groups 4 Species groups .........................................................................................144 4.1 Phytoplankton .................................................................................................... 144 4.2 Macroalgae ........................................................................................................ 159 4.3 Seagrasses ........................................................................................................ 172 4.4 Mangroves ......................................................................................................... 186 4.5 Sponges ............................................................................................................. 192 4.6 Corals................................................................................................................. 199 4.7 Infauna ............................................................................................................... 204 4.8 Zooplankton ....................................................................................................... 212 4.9 Prawns .............................................................................................................. 229 4.10 Rock lobster – southern (Jasus edwardsii)........................................................ 242 4.11 Rock lobster – western ...................................................................................... 251 4.12 Molluscs of commercial, recreational, cultural and ecological significance....... 259 4.13 Bryozoans .......................................................................................................... 275 4.14 Ascidians............................................................................................................ 282 4.15 Elasmobranchs .................................................................................................. 288 4.16 Demersal fish – inshore ..................................................................................... 305 4.17 Demersal fish – shelf.......................................................................................... 397 4.18 Demersal fish – slope ........................................................................................ 412 4.19 Mackerels, tunas and billfishes .......................................................................... 424 4.20 Mesopelagic fish ................................................................................................ 449 4.21 Small pelagic fishes ........................................................................................... 454 4.22 Syngnathid fish (seahorses, seadragons, pipehorses and pipefishes) ............. 469 4.23 Seabirds ............................................................................................................. 520 4.24 Pinnipeds .......................................................................................................... 536 4.25 Cetaceans .......................................................................................................... 558 4.26 Marine pests in South Australia from Kangaroo Island to the Great Australian Bight.................................................................................................. 570 3 Acknowledgments We recognise that contributions to this report were made by many people (listed as contributing authors) who had no financial investment in the project. We are grateful for the time and effort that these people put into contributing species group descriptions. Each species group was independently reviewed by external experts who donated their time; this was much appreciated. We thank these reviewers for their contributions: Alice Morris, Anthony Hart, Glen Moore, Gary Kendrick, Charlie Veron, Nick Dunlop, Curt Jenner, Dan Gaughan, Roy Melville-Smith, Mervi Kangas, Neil Loneragan, Peter Shaughnessy, Kevin Mcloughlin, Jock Young, Marinelle Basson, Jacob John, Janine Baker, John Hooper, Nic Bax, Peter Last, Patricia Mather, Phil Bock, Richard Campbell, Sabine Dittman and Scoresby Shepherd. We are also grateful to Jason Tanner and Anthony Cheshire for providing helpful comments in the SARDI internal review process. Two anonymous reviewers engaged by the Department of the Environment and Water Resources also improved the draft report. Shirley Sorokin provided valuable assistance with report preparation. We would particularly like to thank Patricia Baumgarten for her enthusiastic endorsement of our efforts to deliver this report, and her commitment to the project during her time at the Department of the Environment and Water Resources. This project was funded by the Department of the Environment and Water Resources (contract NOOC 2004/061 Review of ecological information and knowledge of Australia's South-west Marine Region). Funding was secured by Tim Ward, Chari Pattiaratchi, Sam McClatchie and John Middleton. 4 Executive summary 1 Executive summary 1.1 Purpose, focus, and structure of the report The purpose of this report was to undertake a comprehensive review of the current knowledge of the key ecological characteristics of the South-west Marine Region (the Region). This region covers Australian waters from the eastern-most tip of Kangaroo Island (South Australia) to the outer coast of Shark Bay (Western Australia) (Figure 1.1.1). The focus of this report is waters beyond three nautical miles from the coastal baseline; information on inshore waters is included only where there are important processes that influence processes on the shelf and slope. The objective is to produce an integrated report on the ecosystem of the Region, which is aimed at scientists who are not necessarily specialists in the area. The information embodied in the report will provide background to inform policy decisions where there is a need for scientific information about the region; information that was previously widely scattered and less accessible. The Department of the Environment and Water Resources defined a list of functional groups of organisms that have either commercial (target and significant by-catch species), recreational,