Are circle hooks effective in reducing incidental captures of loggerhead sea turtles in a Mediterranean longline fishery?

  • Published source details Piovano S., Swimmer Y. & Giacoma C. (2009) Are circle hooks effective in reducing incidental captures of loggerhead sea turtles in a Mediterranean longline fishery?. Aquatic Conservation: Marine and Freshwater Ecosystems, 19, 779-785.


This study is summarised as evidence for the following.

Action Category

Use circle hooks instead of J-hooks

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

    A replicated, controlled study in 2005–2007 in pelagic waters in the Mediterranean Sea, Italy and Tunisia (Piovano et al. 2009) found that circle hooks caught fewer immature loggerhead turtles Caretta caretta than J-hooks in a shallow-set swordfish Xiphias gladius longline fishery. Unwanted catch of immature sea turtles was lower when circle hooks (0.4 individuals/1,000 hooks) were used compared to J-hooks (1.4). Five of 20 turtles swallowed J-hooks, compared to none of six turtles caught with circle hooks (results were not statistically tested). Catch rates of commercially targeted swordfish were similar between hook types (circle: 13 individuals/1,000 hooks, J: 15). Catch rates of 10° offset 16/0 circle hooks (2.7 cm gape width) were compared with traditional 20° offset size 2 J-hooks (2.6 cm gape width). Seven experimental trips were conducted using a single commercial fishing boat, totalling 30 fishing sets in July–October 2005–2007. Circle and J-hooks were alternated along the mainline (30,000 total hooks, 50% of each type).

    (Summarised by: Maggie Watson, Katie Sainsbury)

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