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Assessment of the Blue Swimmer Crab (Portunus Armatus) Fishery in Queensland

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Assessment of the Blue Swimmer Crab (Portunus Armatus) Fishery in Queensland Assessment of the blue swimmer crab (Portunus armatus) fishery in Queensland This publication has been compiled by Wayne Sumpton, Matthew Campbell, Michael O’Neill, Mark McLennan, Alex Campbell and George Leigh of Sustainable Fisheries, Department of Agriculture and Fisheries, and You-Gan Wang and Luke Lloyd-Jones of the University of Queensland. © State of Queensland, 2015. The Queensland Government supports and encourages the dissemination and exchange of its information. The copyright in this publication is licensed under a Creative Commons Attribution 3.0 Australia (CC BY) licence. Under this licence you are free, without having to seek our permission, to use this publication in accordance with the licence terms. You must keep intact the copyright notice and attribute the State of Queensland as the source of the publication. Note: Some content in this publication may have different licence terms as indicated. For more information on this licence, visit http://creativecommons.org/licenses/by/3.0/au/deed.en The information contained herein is subject to change without notice. The Queensland Government shall not be liable for technical or other errors or omissions contained herein. The reader/user accepts all risks and responsibility for losses, damages, costs and other consequences resulting directly or indirectly from using this information Table of Contents 1. INTRODUCTION AND BACKGROUND ................................................................... 13 HISTORICAL DEVELOPMENT OF THE BLUE SWIMMER CRAB FISHERY IN QUEENSLAND................................... 13 RECENT MANAGEMENT HISTORY ............................................................................................................................... 14 MANAGEMENT ARRANGEMENTS IN OTHER JURISDICTIONS ................................................................................... 15 OBJECTIVES AND SCOPE OF THE REPORT .................................................................................................................. 19 2. ANALYSIS OF BLUE SWIMMER CRAB CATCH AND EFFORT DATA .................. 21 CATCH .............................................................................................................................................................................. 22 EFFORT ............................................................................................................................................................................ 23 CATCH PER UNIT EFFORT .............................................................................................................................................. 24 POT DATA ISSUES ........................................................................................................................................................... 25 CATCH RATE STANDARDISATION ................................................................................................................................. 28 MODEL OUTPUTS ............................................................................................................................................................ 29 Moreton Bay ................................................................................................................................... 29 Sunshine Coast and Hervey Bay ................................................................................................... 32 Fisheries Queensland Independent Trawl Surveys ....................................................................... 33 3. CHANGES IN FISHERIES BIOLOGY AND POPULATION BIOLOGY ..................... 35 INTRODUCTION ............................................................................................................................................................... 35 MATERIALS AND METHODS ......................................................................................................................................... 35 RESULTS .......................................................................................................................................................................... 37 DISCUSSION ..................................................................................................................................................................... 42 4. PARASITISM AND DISEASES ................................................................................. 45 INTRODUCTION ............................................................................................................................................................... 45 MATERIALS AND METHODS ......................................................................................................................................... 45 RESULTS .......................................................................................................................................................................... 46 DISCUSSION ..................................................................................................................................................................... 48 5. ENVIRONMENTAL INFLUENCES ON THE FISHERY ............................................. 49 INTRODUCTION AND METHODS ................................................................................................................................... 49 RESULTS/DISCUSSION .................................................................................................................................................. 50 6. COMMERCIAL FISHERY ECONOMICS ................................................................... 53 INTRODUCTION AND METHODS ................................................................................................................................... 53 RESULTS/DISCUSSION .................................................................................................................................................. 54 7. POPULATION MODELLING AND STOCK ASSESSMENT ..................................... 59 INTRODUCTION ............................................................................................................................................................... 59 MATERIALS AND METHODS ......................................................................................................................................... 59 Population Model and Parameters ................................................................................................ 59 Economic Model and Parameters .................................................................................................. 65 RESULTS/DISCUSSION .................................................................................................................................................. 66 8. REFERENCES .......................................................................................................... 74 9. APPENDICES ........................................................................................................... 78 APPENDIX 1 GROWTH ESTIMATION VIA MIXTURE MODELS AND THE MM ALGORITHM ................................ 78 Introduction .................................................................................................................................... 78 Materials and methods................................................................................................................... 79 Results/Discussion ......................................................................................................................... 83 References ..................................................................................................................................... 90 1 APPENDIX 2: MODEL INPUTS ...................................................................................................................................... 91 MODEL OUTPUTS ........................................................................................................................................................... 97 Moreton Bay and Sunshine Coast ................................................................................................. 97 Hervey Bay .................................................................................................................................. 108 2 List of Figures Figure 1: Number of blue swimmer crabs marketed through the Queensland Fish Board from 1937 to 1975 and numbers recorded in CFISH logs (1988 to 2013). The blue line shows the volume marketed through the Brisbane Metropolitan Markets while the upper line is the total marketed from all agencies throughout the state. ................................................................ 13 Figure 2: Annual blue swimmer crab catch, in tonnes, for the a) pot and b) trawl fisheries. ............... 21 Figure 3: Extent of geographic regions and relevant CFISH reporting grid used in commercial logbooks for both trawl and pot fisheries. Taken from Sumpton et al. (2003), page 10. ...... 22 Figure 4: Annual blue swimmer crab catch, in tonnes, for the a) pot and b) trawl fisheries as a function of spatial region in southern Queensland. .............................................................. 23 Figure 5: Annual blue swimmer crab effort for the a) pot and b) trawl fisheries as a function of spatial region in southern Queensland. ........................................................................................... 24 Figure 6: Annual number of boats reporting
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