Abstract
Data from voluntary logbooks (5,884 longline sets) collected between 1997 and 2000 were analyzed to assess the potential impact of the Reunion-based longline swordfish fishery (South West Indian Ocean) on sharks and on sea turtle populations. Blue shark (Prionace glauca) represented between 75% and 88% of the total catches of sharks studied. Bycatch discarding varied with species, ranging from low discards (2.6%) for mako shark (Isurus sp.) to high discards for blue shark (86.5%). Estimation of the total catch of sharks (retained and discarded individuals) represented in weight between 7% and 9% of the total catch of the major species caught by the fishery. Of concern is the decline of blue shark CPUE (Catch Per Unit of Effort) from 2.2 to 1.03 sharks per 1,000 hooks between 1998 and 2000. Of the 22,974 hook-timers deployed during cruises onboard commercial, 49% of the blue shark (Prionace glauca) and 41.2% of the oceanic whitetip shark (Carcharhinus longimanus) were retrieved alive. It was assumed that among the 15,250 blue sharks caught during this period, at least 7,099, released alive, could have survived.
The observed sea turtle catch rates were low compared with those reported for other longline fisheries. The fishery had 47 interactions with Leatherback (Dermochelys coriacea), 30 with Hawksbill turtles (Eretmochelys imbricata), and 16 with Green turtles (Chelonia mydas).
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References
Anonymous (2007) Report of the third session of the IOTC working party on ecosystems and by-catch. Seychelles, 11–13 July 2007
Bonfil R (1994) Overview of world elasmobranch fisheries. Fisheries Technical Paper, vol 341. FAO, Rome
Buencuerpo V, Ríos S, Morón J (1998) Pelagic sharks associated with the swordfish, Xiphias gladius, fishery in the eastern North Atlantic Ocean and the Strait of Gibraltar. Fish Bull 96:667–685
Francis MP, Griggs LH, Baird SJ (2001) Pelagic shark bycatch in the New Zealand tuna longline fishery. Mar Freshwater Res 52(2):165–178
Gilman E, Kobayashi D, Swenarton T, Brothers N, Dalzell P, Kinan-Kelly I (2007) Reducing sea turtle interactions in the Hawaii-based longline swordfish fishery. Biol Conserv 139(1–2):19–28
Lewison RL, Crowder LB (2007) Putting longline bycatch of sea turtles into perspective. Conserv Biol 21:79–86
Moyes C, Fragoso N, Musyl M, Brill R (2006) Developing physiological and biochemical indices of survival in released blue sharks. T Am Fish Soc 135:1389–1397
Pinedo MC, Polacheck T (2003) Sea turtle by-catch in pelagic longline sets off southern Brazil. Biol Conserv 119:335–339
Ward P. Myers RA, Blanchard W (2004) Fish lost at sea: the effect of soak time on pelagic longline catches. Fish Bull 102(1):179–195
Ward P, Lawrence E, Darbyshire R, Hindmarsh S (2008) Large-scale experiment shows that nylon leaders reduce shark bycatch and benefit pelagic longline fishers. Fish Res 90:100–108
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Poisson, F. (2010). Catch, Bycatch of Sharks, and Incidental Catch of Sea Turtles in the Reunion-Based Longline Swordfish Fishery (Southwest Indian Ocean) Between 1997 and 2000. In: Ceccaldi, HJ., Dekeyser, I., Girault, M., Stora, G. (eds) Global Change: Mankind-Marine Environment Interactions. Springer, Dordrecht. https://doi.org/10.1007/978-90-481-8630-3_29
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DOI: https://doi.org/10.1007/978-90-481-8630-3_29
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