Do circle hooks reduce the mortality of sea turtles in pelagic longlines? A review of recent experiments

  • Published source details Read A.J. (2007) Do circle hooks reduce the mortality of sea turtles in pelagic longlines? A review of recent experiments. Biological Conservation, 135, 155-169.


This study is summarised as evidence for the following.

Action Category

Use circle hooks instead of J-hooks

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Reptile Conservation
  1. Use circle hooks instead of J-hooks

    A review of studies in 2000–2004 in five pelagic longline fisheries in the western North Atlantic, Azores, Gulf of Mexico and Ecuador (Read 2007) found that using circle hooks instead of traditional J-hooks reduced overall unwanted catch in three of five fisheries and mortality rates of sea turtles in four of the fisheries. Unwanted catch reduced significantly in two of five fisheries and in one of four years in a third fishery. Sea turtle mortality rates reduced significantly in four of five fisheries. Switching to circle hooks from J-hooks was considered economically viable in three of five fisheries, not viable in a fourth (as target catch was reduced significantly) and the impact was unknown in the fifth. The fisheries were for tuna Thunnus spp. and mahi mahi Coryphaena hippurus. Experiments comparing use of circle hooks (offset and non-offset of different sizes, see original paper) with traditional J-hooks were carried out in 2000–2004 on longline vessels (1–136 vessels/fishery, 48–489 deployments/fishery with 20,570–578,050 hook deployments/fishery).

    (Summarised by: Katie Sainsbury)

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