Northern Zone Rock Lobster (Jasus Edwardsii) Fishery 2004/05
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Final Stock Assessment Report to PIRSA Fisheries Northern Zone Rock Lobster (Jasus edwardsii) Fishery 2004/05 A. Linnane, R. McGarvey, J. Feenstra and T. M. Ward May 2006 SARDI Research Report Series No. RD04/0165-3 This report is the fourth version of a “living” document that is updated annually as part of SARDI Aquatic Sciences’ ongoing fishery assessment program for South Australia’s Northern Zone Rock Lobster Fishery. The report provides a synopsis of information available for the fishery and assesses the current status of the resource. The report also identifies both current and future research needs for the fishery. Title: Northern Zone Rock Lobster (Jasus edwardsii) Fishery 2004/05 Sub-title: Final Stock Assessment Report to PIRSA Fisheries 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 The authors warrant that they have taken all reasonable care in producing this report. This report has been through SARDI Aquatic Sciences internal review process, and was formally approved for release by the Chief Scientist. Although all reasonable efforts have been made to ensure quality, SARDI Aquatic Sciences does not warrant that the information in this report is free from errors or omissions. SARDI Aquatic Sciences 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. © 2006 SARDI Aquatic Sciences 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 author. Printed in Adelaide May 2006. SARDI Aquatic Sciences Publication No. RD04/0165-3 SARDI Research Report Series No. 136 Authors: A. Linnane, R. McGarvey, J. Feenstra and T. M. Ward. Reviewers: Dr John Carragher, Dr Simon Bryars & Mr. Sean Sloan Approved by: Dr Anthony Fowler Signed: Date: May 31st, 2006 Distribution: PIRSA Fisheries, Northern Zone Rock Lobster Fishery Management Committee, SARDI Aquatic Sciences Library, Northern Zone Rock Lobster licence holders Circulation: Public Domain ii TABLE OF CONTENTS TABLE OF CONTENTS.......................................................................................................................1 ACKNOWLEDGEMENTS ...................................................................................................................3 EXECUTIVE SUMMARY ....................................................................................................................4 1 GENERAL INTRODUCTION....................................................................................................7 1.1 Overview ..............................................................................................................................7 1.2 Description of the Fishery...................................................................................................8 1.2.1 Location and Size .............................................................................................................8 1.2.2 Environmental Characteristics..........................................................................................8 1.2.3 Commercial Fishery .......................................................................................................11 1.2.4 Recreational Fishery.......................................................................................................12 1.2.5 Illegal fishing..................................................................................................................13 1.3 Management of the Fishery ..............................................................................................13 1.3.1 Management Milestones.................................................................................................13 1.3.2 Current Management Arrangements...............................................................................14 1.3.3 Management Objectives and Strategies..........................................................................15 1.3.4 Performance Indicators and Reference Points ................................................................17 1.3.5 Management action on reaching a reference point outside the historical range. ............18 1.4 Biology of Southern Rock Lobster...................................................................................19 1.4.1 Taxonomy and Distribution............................................................................................19 1.4.2 Stock Structure ...............................................................................................................19 1.4.3 Life History ....................................................................................................................20 1.4.4 Growth and Size at Maturity...........................................................................................21 1.4.5 Movement.......................................................................................................................22 1.5 Previous Stock Assessments..............................................................................................23 1.6 Current Research and Monitoring Programs.................................................................24 1.6.1 Catch and Effort Research Logbook...............................................................................24 1.6.2 Pot Sampling ..................................................................................................................25 1.6.3 Puerulus Monitoring Program ........................................................................................26 1.6.4 Octopus Predation Project ..............................................................................................27 1.6.5 By-catch monitoring Program ........................................................................................28 2 FISHERY STATISTICS ............................................................................................................30 2.1 Introduction .......................................................................................................................30 2.2 Catch, Effort and CPUE ...................................................................................................30 2.2.1 Inter-annual Patterns.......................................................................................................30 2.2.2 Within-season Patterns ...................................................................................................33 2.2.3 Patterns across MFAs .....................................................................................................40 2.3 Patterns by depth...............................................................................................................44 2.4 Mean Weights ....................................................................................................................49 2.4.1 Inter-annual Pattern ........................................................................................................49 2.4.2 Within-season Patterns ...................................................................................................49 2.4.3 Patterns across MFA’s....................................................................................................50 2.5 Length Frequency..............................................................................................................53 2.6 Pre-Recruit Index..............................................................................................................59 2.6.1 Inter-annual pattern (commercial logbook data).............................................................59 2.6.2 Inter-annual pattern (voluntary catch sampling data) .....................................................60 2.6.3 Within season trends (voluntary catch sampling data) ...................................................60 2.6.4 Patterns across MFAs (catch sampling data)..................................................................62 1 2.7 Settlement Index................................................................................................................64 3 THE qR MODEL........................................................................................................................66 3.1 Introduction .......................................................................................................................66 3.2 Methods..............................................................................................................................67 3.3 Results ................................................................................................................................69 3.4 Discussion...........................................................................................................................75 4 PERFORMANCE INDICATORS.............................................................................................77 4.1 Catch...................................................................................................................................77 4.2 Catch rate...........................................................................................................................77 4.3 Mean Weight......................................................................................................................77