The Effect of Western Rock Lobster Fishing on the Deepwater Ecosystems of the West Coast of Western Australia Final FRDC Report – Project No
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Fisheries Research Report No. 199, 2010 The effect of western rock lobster fishing on the deepwater ecosystems of the west coast of Western Australia Final FRDC Report – Project No. 2004/049 Dr Lynda Bellchambers Australian Government Fisheries Research and Development Corporation Fisheries Research Division Western Australian Fisheries and Marine Research Laboratories PO Box 20 NORTH BEACH, Western Australia 6920 Correct citation: Bellchambers, L. 2010. The effect of western rock lobster fishing on the deepwater ecosystems of the west coast of Western Australia. Final FRDC Report, Project 2004/049. Department of Fisheries, Government of Western Australia. 96pp. Enquiries: WA Fisheries and Marine Research Laboratories, PO Box 20, North Beach, WA 6920 Tel: +61 8 9203 0111 Email: [email protected] Website: www.fish.wa.gov.au ABN: 55 689 794 771 A complete list of Fisheries Research Reports is available online at www.fish.wa.gov.au Disclaimer The authors do not warrant that the information in this document is free from errors or omissions. The authors do not accept any form of liability, be it contractual, tortious, or otherwise, for the contents of this document or for any consequences arising from its use or any reliance placed upon it. The information, opinions and advice contained in this document may not relate, or be relevant, to a readers particular circumstances. Opinions expressed by the authors are the individual opinions expressed by those persons and are not necessarily those of the publisher, research provider or the FRDC. This work is copyright. Except as permitted under the Copyright Act 1968 (Cth), no part of this publication may be reproduced by any process, electronic or otherwise, without the specific written permission of the copyright owners. Information may not be stored electronically in any form whatsoever without such permission. The Fisheries Research and Development Corporation plans, invests in and manages fisheries research and development throughout Australia. It is a statutory authority within the portfolio of the federal Minister for Agriculture, Fisheries and Forestry, jointly funded by the Australian Government and the fishing industry. © Department of Fisheries, Western Australia. February 2010. ISSN: 1035 - 4549 ISBN: 1 921258 76 4 ii Fisheries Research Report [Western Australia] No. 199, 2010 Contents Objectives................................................................................................................................ 1 Non.Technical.Summary....................................................................................................... 2 Outcomes achieved to date ............................................................................................ 2 Acknowledgements................................................................................................................ 4 1.0 Background..................................................................................................................... 5 1.1 Need ........................................................................................................................ 5 1.2 Objectives ............................................................................................................... 6 2.0 General.Introduction..................................................................................................... 7 2.1 Reporting format ..................................................................................................... 8 3.0 Assessment.Of.The.Benthic.Biota.Of.Deep-Coastal.Ecosystems.Associated.. With.Western.Rock.Lobster.(Panulirus Cygnus).Populations.Along.The. Temperate.West.Coast.Of.Australia............................................................................. 10 3.1 Summary ................................................................................................................. 10 3.2 Abstract ................................................................................................................... 10 3.3 Introduction ............................................................................................................ 11 3.4 Materials and methods ............................................................................................ 12 3.4.1 Study locations ............................................................................................. 12 3.4.2 Determining broad-scale habitat characteristics using towed video .................................................................................................. 12 3.4.3 Data analysis ............................................................................................... 13 3.4.4 Determining fine-scale and macroinvertebrate characteristics by diver sampling .............................................................................................. 13 3.4.5 Data analysis ................................................................................................ 13 3.4.6 Comparison of broad-scale and fine-scale methods of habitat classification ............................................................................................... 13 3.5 Results ..................................................................................................................... 14 3.5.1 Broad-scale patterns in sponge/algal assemblage structure determined from towed video ........................................................................................ 14 3.5.2 Fine-scale patterns in sponge/algal assemblage structure determined by diver sampling ........................................................................................ 15 3.5.3 Macroinvertebrate community composition determined by diver sampling .............................................................................................. 15 3.5.4 Comparison of total sponge, algal and macroinvertebrate abundances ...... 16 3.5.5 Comparison of broad-scale and fine-scale methods of habitat classification ............................................................................................... 16 3.6 Discussion .............................................................................................................. 16 3.6.1 Towed video as a surrogate for diver sampling in classification of sponge and algal assemblages ..................................................................... 17 3.6.2 Conclusions .................................................................................................. 18 Fisheries Research Report [Western Australia] No. 199, 2010 iii 3.7 Tables ...................................................................................................................... 19 3.8 Figures .................................................................................................................... 21 4.0 Abundance.and.size.of.western.rock.lobster.(Panulirus cygnus).as.a.function. of.benthic.habitat:.implications.for.ecosystem.based.fisheries.management.. (EBFM)............................................................................................................................ 25 4.1 Summary ................................................................................................................. 25 4.2 Abstract ................................................................................................................... 25 4.3 Introduction ............................................................................................................. 26 4.4 Methods .................................................................................................................. 27 4.4.1 Study locations and the Independent Breeding Stock Survey (IBSS) ........ 27 4.4.2 Habitat classification by towed video transects ......................................... 27 4.4.3 Statistical analysis ........................................................................................ 28 4.5 Results ..................................................................................................................... 29 4.5.1 Habitat .......................................................................................................... 29 4.5.2 Lobster ......................................................................................................... 29 4.5.3 Modelling lobsters and their habitats .......................................................... 29 4.6 Discussion ............................................................................................................... 30 4.7 Tables ...................................................................................................................... 32 4.8 Figures .................................................................................................................... 34 5.0 Predicting.western.rock.lobster.(Panulirus cygnus).abundance.and.size.based. on.habitat.characteristics.at.Jurien,.Western.Australia............................................. 39 5.1 Summary ................................................................................................................. 39 5.2 Abstract ................................................................................................................... 39 5.3 Introduction ............................................................................................................. 40 5.4 Methods .................................................................................................................