Shark catch in a pelagic longline fishery: comparison of circle and tuna hooks

  • Published source details Yokota K., Kiyota M. & Minami H. (2006) Shark catch in a pelagic longline fishery: comparison of circle and tuna hooks. Fisheries Research, 81, 337-341.


This study is summarised as evidence for the following.

Action Category

Use a different hook type

Action Link
Marine Fish Conservation
  1. Use a different hook type

    A replicated, controlled study in 2005 in an area of coastal, pelagic water in the western North Pacific, off Japan (Yokota et al. 2006) found that changing hook type and size to a circle hook from a standard hook did not reduce the unwanted catches, or capture mortality, of blue shark Prionace glauca in a longline fishery. Across both vessels, average blue shark catch rates were similar with larger hook sizes and different shape compared to the standard (largest: 36–94, intermediate: 38–95, standard: 41–82 sharks/1,000 hooks). Similarly, the proportion of dead individuals did not differ between hook types (data reported as statistical results). Data were collected on two research vessels from 52 fishing deployments between May–September 2005. A total of 900 hooks were used/longline deployment on one vessel and 960 hooks/longline for the other (all baited with Japanese common squid Todarodes pacificus). Blocks of 20 hooks of each of two test hook types (5.2 and 4.3 size circle hooks) and a standard Japanese hook type (3.8 size tuna hook) were fished in a repeating pattern on the longline. During hauling the species, number and condition of fish caught were recorded.

    (Summarised by: Chris Barrett)

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