West Coast Prawn Penaeus (Melicertus) latisulcatus Fishery 2012–13 C.L. Beckmann, G. E. Hooper and C. J. Noell SARDI Publication No. F2007/000772-6 SARDI Research Report Series No. 808 SARDI Aquatics Sciences PO Box 120 Henley Beach SA 5022 November 2014 Fishery Assessment Report to PIRSA Fisheries and Aquaculture Beckmann et al., (2014) West Coast Prawn Fishery 2012–13 West Coast Prawn Penaeus (Melicertus) latisulcatus Fishery 2012–13 Fishery Assessment Report to PIRSA Fisheries and Aquaculture C. L. Beckmann, G. E. Hooper and C. J. Noell SARDI Publication No. F2007/000772-6 SARDI Research Report Series No. 808 November 2014 II Beckmann et al., (2014) West Coast Prawn Fishery 2012–13 This publication may be cited as: Beckmann, C. L., Hooper, G. E. and Noell, C. J. (2014). West Coast Prawn Penaeus (Melicertus) latisulcatus Fishery 2012–13. Fishery Assessment Report to PIRSA Fisheries and Aquaculture. South Australian Research and Development Institute (Aquatic Sciences), Adelaide. SARDI Publication No. F2007/000772-6. SARDI Research Report Series No. 808. 76pp. Front cover photo: West Coast Survey, March 2007 (Shane Roberts) South Australian Research and Development Institute SARDI Aquatic Sciences 2 Hamra Avenue West Beach SA 5024 Telephone: (08) 8207 5400 Facsimile: (08) 8207 5406 http://www.sardi.sa.gov.au DISCLAIMER The authors warrant that they have taken all reasonable care in producing this report. The report has been through the SARDI internal review process, and has been formally approved for release by the Research Chief, Aquatic Sciences. Although all reasonable efforts have been made to ensure quality, SARDI does not warrant that the information in this report is free from errors or omissions. SARDI does not accept any liability for the contents of this report or for any consequences arising from its use or any reliance placed upon it. The SARDI Report Series is an Administrative Report Series which has not been reviewed outside the department and is not considered peer-reviewed literature. Material presented in these Administrative Reports may later be published in formal peer-reviewed scientific literature. © 2014 SARDI This work is copyright. Apart from any use as permitted under the Copyright Act 1968 (Cth), no part may be reproduced by any process, electronic or otherwise, without the specific written permission of the copyright owner. Neither may information be stored electronically in any form whatsoever without such permission. Printed in Adelaide: November 2014 SARDI Publication No. F2007/000772-6 SARDI Research Report Series No. 808 Author(s): C. L. Beckmann, G. E. Hooper and C. J. Noell Reviewer(s): G. Fergusson, P. Rogers (SARDI), and B. Milic (PIRSA) Approved by: S. Mayfield Science Leader - Fisheries Signed: Date: 14 November 2014 Distribution: PIRSA Fisheries and Aquaculture, SAASC Library, University of Adelaide Library, Parliamentary Library, State Library and National Library Circulation: Public Domain III Beckmann et al., (2014) West Coast Prawn Fishery 2012–13 TABLE OF CONTENTS LIST OF FIGURES ............................................................................................................... V LIST OF TABLES .............................................................................................................. VIII ACKNOWLEDGEMENTS .................................................................................................... IX EXECUTIVE SUMMARY ...................................................................................................... 1 1. INTRODUCTION .............................................................................................................. 2 1.1. Overview ...................................................................................................................................... 2 1.2. Description of the fishery.............................................................................................................. 3 1.3. Management of the fishery ........................................................................................................ 10 1.4. Biology of the western king prawn ............................................................................................. 13 1.5. Previous fishery assessments ................................................................................................... 27 1.6. Research program ..................................................................................................................... 28 1.7. Information used for assessment ............................................................................................... 28 2. METHODS ...................................................................................................................... 29 2.1. Stock assessment surveys ........................................................................................................ 29 2.2. Catch and effort statistics ........................................................................................................... 31 2.3. Environmental variables ............................................................................................................. 34 2.4. Performance indicators .............................................................................................................. 34 2.5. Quality assurance of data .......................................................................................................... 35 3. RESULTS ....................................................................................................................... 37 3.1. Stock Assessment Surveys........................................................................................................ 37 3.2. Catch and effort statistics ........................................................................................................... 43 3.3. Environmental variables ............................................................................................................. 52 3.4. Fishery performance .................................................................................................................. 54 4. DISCUSSION .................................................................................................................. 59 4.1. Current status of the West Coast Prawn Fishery ....................................................................... 59 4.2. Harvest strategy for the WCPF .................................................................................................. 60 4.3. Future research needs ............................................................................................................... 64 5. REFERENCES ............................................................................................................... 65 6. APPENDIX ..................................................................................................................... 72 IV Beckmann et al., (2014) West Coast Prawn Fishery 2012–13 LIST OF FIGURES Figure 1.1 Location of South Australia’s three commercial prawn fisheries. .......................................... 3 Figure 1.2 Upper panel: A schematic of some key circulation features for winter in the Great Australian Bight. The Leeuwin Current (LC), Leeuwin Undercurrent (LUC), Flinders Current (FC) and shelf-edge South Australian Current (SA Current) are show. Dense salty water is downwelled from the Gulfs. Lower panel: summertime circulation and upwelling occurs of Kangraroo Island and the Bonney Coast. Shelf-edge downwelling may occur in the western GAB. Figure adapted from Middleton and Bye (2007). ................................................................... 4 Figure 1.3 Mean monthly sea surface temperatures for the South Australian and Western Australian (WA) prawn fisheries that target western king prawn. .................................................................... 5 Figure 1.4 Sea surface temperatures (ºC) of the continental shelf and gulf waters of South Australia during January 2012. Source: Physical Oceanography Distributed Active Archive Center (NASA, 2013) ............................................................................................................................................... 6 Figure 1.5 Important juvenile nursery habitat, mangrove forest and tidal flats, around the West Coast. ........................................................................................................................................................ 7 Figure 1.6 Double rig trawl gear and location of hopper sorting and prawn grading systems used in the WCPF. Figure from Carrick (2003). .......................................................................................... 9 Figure 1.7 Trawl net configuration showing trawl boards, head rope, ground chain and cod end with crab bag. Figure from Carrick (2003). ............................................................................................. 9 Figure 1.8 Logistic relationship between carapace length and sexual maturity for female western king prawns in Spencer Gulf. Source: Noell et al., (2013). ................................................................... 15 Figure 1.9 Relationship between carapace length and fecundity for female western king prawns in Gulf St Vincent (GSV) and Shark Bay, Western Australia (WA). Source: Noell et al., (2013). .... 15 Figure 1.10 Life cycle of a penaeid prawn. Source: Kailola et al., (1993). ..........................................