TY - JOUR

T1 - Fishing for the facts: river dolphin bycatch in a small-scale freshwater fishery in Bangladesh

AU - Richman, Nadia

AU - Jones, J.P.G.

AU - Northridge, Simon

AU - Brook , Sarah

AU - Freeman, Robin

AU - Jepson, Paul

AU - Mahood, Simon

AU - Turvey, Samuel

PY - 2020/4

Y1 - 2020/4

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.

KW - Ganges River dolphin

KW - Platanista gangetica gangetica

KW - bycatch

KW - freshwater cetaceans

KW - gillnet

KW - interview data

KW - local informant data

KW - small-scale fisheries

U2 - 10.1111/acv.12523

DO - 10.1111/acv.12523

M3 - Article

VL - 23

SP - 160

EP - 170

JO - Animal Conservation

JF - Animal Conservation

SN - 1367-9430

IS - 2

ER -