Fishing for the facts

river dolphin bycatch in a small-scale freshwater fishery in Bangladesh

N. I. Dewhurst-Richman, J. P.G. Jones, S. Northridge, B. Ahmed, S. Brook, R. Freeman, P. Jepson, S. P. Mahood, S. T. Turvey

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    Fisheries bycatch is a primary driver of cetacean declines, especially for threatened freshwater cetaceans. However, information on the factors influencing cetacean susceptibility to bycatch in small-scale fisheries is limited, impeding development of evidence-based conservation strategies. We conducted 663 interviews with fishers from southern Bangladesh to investigate the influence of net and set characteristics on seasonal bycatch rates of Ganges River dolphins Platanista gangetica gangetica and assess the sustainability of annual mortality levels. Between October 2010–October 2011, 170 bycatch events (and a minimum of 14 mortalities) were reported, 89% of which occurred in gillnets. The probability of bycatch increased as water depth declined, and as net mesh size increased. While the number of recorded bycatch incidents was higher in gillnets, risk of mortality was greater in set bagnets. Our mortality estimate indicates that fisheries-related bycatch currently exceeds the sustainable limit recommended by the International Whaling Commission by 3.5 times. Numerous regulations have been developed to improve the productivity of commercially important fisheries, and if regulations were effectively enforced, these may also reduce river dolphin bycatch.

    Original languageEnglish
    Pages (from-to)1-11
    Number of pages11
    JournalAnimal Conservation
    DOIs
    Publication statusE-pub ahead of print - 1 Aug 2019

    Fingerprint

    dolphin
    bycatch
    fishing
    fishery
    river
    cetacean
    mortality
    gillnet
    whaling
    mesh size
    water depth
    sustainability
    productivity

    Cite this

    Dewhurst-Richman, N. I., Jones, J. P. G., Northridge, S., Ahmed, B., Brook, S., Freeman, R., ... Turvey, S. T. (2019). Fishing for the facts: river dolphin bycatch in a small-scale freshwater fishery in Bangladesh. Animal Conservation, 1-11. https://doi.org/10.1111/acv.12523
    Dewhurst-Richman, N. I. ; Jones, J. P.G. ; Northridge, S. ; Ahmed, B. ; Brook, S. ; Freeman, R. ; Jepson, P. ; Mahood, S. P. ; Turvey, S. T. / Fishing for the facts : river dolphin bycatch in a small-scale freshwater fishery in Bangladesh. In: Animal Conservation. 2019 ; pp. 1-11.
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    abstract = "Fisheries bycatch is a primary driver of cetacean declines, especially for threatened freshwater cetaceans. However, information on the factors influencing cetacean susceptibility to bycatch in small-scale fisheries is limited, impeding development of evidence-based conservation strategies. We conducted 663 interviews with fishers from southern Bangladesh to investigate the influence of net and set characteristics on seasonal bycatch rates of Ganges River dolphins Platanista gangetica gangetica and assess the sustainability of annual mortality levels. Between October 2010–October 2011, 170 bycatch events (and a minimum of 14 mortalities) were reported, 89{\%} of which occurred in gillnets. The probability of bycatch increased as water depth declined, and as net mesh size increased. While the number of recorded bycatch incidents was higher in gillnets, risk of mortality was greater in set bagnets. Our mortality estimate indicates that fisheries-related bycatch currently exceeds the sustainable limit recommended by the International Whaling Commission by 3.5 times. Numerous regulations have been developed to improve the productivity of commercially important fisheries, and if regulations were effectively enforced, these may also reduce river dolphin bycatch.",
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    Dewhurst-Richman, NI, Jones, JPG, Northridge, S, Ahmed, B, Brook, S, Freeman, R, Jepson, P, Mahood, SP & Turvey, ST 2019, 'Fishing for the facts: river dolphin bycatch in a small-scale freshwater fishery in Bangladesh', Animal Conservation, pp. 1-11. https://doi.org/10.1111/acv.12523

    Fishing for the facts : river dolphin bycatch in a small-scale freshwater fishery in Bangladesh. / Dewhurst-Richman, N. I.; Jones, J. P.G.; Northridge, S.; Ahmed, B.; Brook, S.; Freeman, R.; Jepson, P.; Mahood, S. P.; Turvey, S. T.

    In: Animal Conservation, 01.08.2019, p. 1-11.

    Research output: Contribution to journalArticleResearchpeer-review

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    AU - Jones, J. P.G.

    AU - Northridge, S.

    AU - Ahmed, B.

    AU - Brook, S.

    AU - Freeman, R.

    AU - Jepson, P.

    AU - Mahood, S. P.

    AU - Turvey, S. T.

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    Y1 - 2019/8/1

    N2 - Fisheries bycatch is a primary driver of cetacean declines, especially for threatened freshwater cetaceans. However, information on the factors influencing cetacean susceptibility to bycatch in small-scale fisheries is limited, impeding development of evidence-based conservation strategies. We conducted 663 interviews with fishers from southern Bangladesh to investigate the influence of net and set characteristics on seasonal bycatch rates of Ganges River dolphins Platanista gangetica gangetica and assess the sustainability of annual mortality levels. Between October 2010–October 2011, 170 bycatch events (and a minimum of 14 mortalities) were reported, 89% of which occurred in gillnets. The probability of bycatch increased as water depth declined, and as net mesh size increased. While the number of recorded bycatch incidents was higher in gillnets, risk of mortality was greater in set bagnets. Our mortality estimate indicates that fisheries-related bycatch currently exceeds the sustainable limit recommended by the International Whaling Commission by 3.5 times. Numerous regulations have been developed to improve the productivity of commercially important fisheries, and if regulations were effectively enforced, these may also reduce river dolphin bycatch.

    AB - Fisheries bycatch is a primary driver of cetacean declines, especially for threatened freshwater cetaceans. However, information on the factors influencing cetacean susceptibility to bycatch in small-scale fisheries is limited, impeding development of evidence-based conservation strategies. We conducted 663 interviews with fishers from southern Bangladesh to investigate the influence of net and set characteristics on seasonal bycatch rates of Ganges River dolphins Platanista gangetica gangetica and assess the sustainability of annual mortality levels. Between October 2010–October 2011, 170 bycatch events (and a minimum of 14 mortalities) were reported, 89% of which occurred in gillnets. The probability of bycatch increased as water depth declined, and as net mesh size increased. While the number of recorded bycatch incidents was higher in gillnets, risk of mortality was greater in set bagnets. Our mortality estimate indicates that fisheries-related bycatch currently exceeds the sustainable limit recommended by the International Whaling Commission by 3.5 times. Numerous regulations have been developed to improve the productivity of commercially important fisheries, and if regulations were effectively enforced, these may also reduce river dolphin bycatch.

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    KW - gillnet

    KW - interview data

    KW - local informant data

    KW - Platanista gangetica gangetica

    KW - small-scale fisheries

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    SN - 1367-9430

    ER -

    Dewhurst-Richman NI, Jones JPG, Northridge S, Ahmed B, Brook S, Freeman R et al. Fishing for the facts: river dolphin bycatch in a small-scale freshwater fishery in Bangladesh. Animal Conservation. 2019 Aug 1;1-11. https://doi.org/10.1111/acv.12523