Global estimates of shark catches using trade records from commercial markets

Authors

  • Shelley C. Clarke,

    Corresponding author
    1. Joint Institute for Marine and Atmospheric Research, University of Hawaii and National Research Institute of Far Seas Fisheries, 5-7-1 Shimizu-Orido, Shizuoka 424-8633, Japan
      E-mail: scclarke@biznetvigator.com
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  • Murdoch K. McAllister,

    1. Division of Biology, Faculty of Life Sciences, Imperial College London, Prince Consort Road, South Kensington Campus, London SW7 2AZ, UK
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  • E. J. Milner-Gulland,

    1. Division of Biology, Imperial College London, Silwood Park Campus, Manor House, Buckhurst Road, Ascot, Berkshire SL5 7PY, UK
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  • G. P. Kirkwood,

    1. Division of Biology, Faculty of Life Sciences, Imperial College London, Prince Consort Road, South Kensington Campus, London SW7 2AZ, UK
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  • Catherine G. J. Michielsens,

    1. Finnish Game and Fisheries Research Institute, Viikinkaari 4, PO Box 2, FIN-00791 Helsinki, Finland
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  • David J. Agnew,

    1. Division of Biology, Faculty of Life Sciences, Imperial College London, Prince Consort Road, South Kensington Campus, London SW7 2AZ, UK
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  • Ellen K. Pikitch,

    1. Pew Institute for Ocean Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
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  • Hideki Nakano,

    1. Fisheries Agency of Japan, 1-2-1 Kasumigaseki, Chiyoda-ku, Tokyo 100-8907, Japan
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  • Mahmood S. Shivji

    1. Guy Harvey Research Institute, Nova Southeastern University Oceanographic Center, 8000 North Ocean Drive, Dania Beach, FL 33004, USA
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E-mail: scclarke@biznetvigator.com

Abstract

Despite growing concerns about overexploitation of sharks, lack of accurate, species-specific harvest data often hampers quantitative stock assessment. In such cases, trade studies can provide insights into exploitation unavailable from traditional monitoring. We applied Bayesian statistical methods to trade data in combination with genetic identification to estimate by species, the annual number of globally traded shark fins, the most commercially valuable product from a group of species often unrecorded in harvest statistics. Our results provide the first fishery-independent estimate of the scale of shark catches worldwide and indicate that shark biomass in the fin trade is three to four times higher than shark catch figures reported in the only global data base. Comparison of our estimates to approximated stock assessment reference points for one of the most commonly traded species, blue shark, suggests that current trade volumes in numbers of sharks are close to or possibly exceeding the maximum sustainable yield levels.

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