Circle hook effectiveness for the mitigation of sea turtle bycatch and capture of target species in a Brazilian pelagic longline fishery


Sales, G., Giffoni, B.B., Fiedler, F.N., Azevedo, V., Kotas, J.E., Swimmer, Y. and Bugoni, L.



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Aquatic Conservation: Marine and Freshwater Ecosystems

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The effectiveness of 18/0 circle hooks, compared to 9/0 J-type hooks, in decreasing the incidental capture and post-release mortaliity of sea turtles, was tested in the Brazilian pelagic longline fishery operating in the south-western Atlantic Ocean.  The incidental capture of loggerhead sea turtles was reduced by 55% and for leatherback sea turtles by 65% when circle hooks were used.  De-hooking also decreased from 25% to 5.8% in loggerhead sea turtles when circle hooks were used, likely increasing their post-release survival rates.  Catch rates of targeted species including bigeye and albacore tuna and blue sharks increased with the use of circle hooks, while no difference in catch rates between hook types was found for yellowfin tuna, shortfin mako or hammerhead sharks or for dolphinfish.  However, swordfish, another target species, catch rates were significantly reduced with the use of circle hooks.