Interactions of loggerhead turtle with bottom longline fishery in the Gulf of Gabès, Tunisia

Published source details Echwikhi K., Jribi I., Bradai M.N. & Bouain A. (2012) Interactions of loggerhead turtle with bottom longline fishery in the Gulf of Gabès, Tunisia. Journal of the Marine Biological Association of the United Kingdom, 92, 853-858.
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This study is summarised as evidence for the following.

	Action	Category
	Reduce duration of time fishing gear is in the water Action Link

Reduce duration of time fishing gear is in the water

A randomized study in 2007–2008 on the sea bottom in the Gulf of Gabès, Tunisia (Echwikhi et al. 2012) found that reducing the time longlines were in the water did not reduce the rate of unwanted catch of loggerhead turtles Caretta caretta in a bottom longline fishery, but did reduce the mortality rate of turtles caught. A similar number of turtles were caught when lines were retrieved immediately (immediate retrieval: 0.18 turtles/1,000 hooks) or left in the water for longer periods (1–2 hour soak: 0.34 turtles/1,000 hooks; >2 hours soak: 0.49 turtles/1,000 hooks; 16 turtles in total). Mortality rates of turtles caught accidentally were lower when bottom longlines were retrieved immediately (0/3 turtles died) compared to when longlines were retrieved after 1–2 hours (2/6 turtles died) or after more than 2 hours (5/7 turtles died). Turtle data was collected by onboard observers in 38 bottom longline deployments during 20 randomly selected fishing trips (1–3 deployments/trip) in July–September 2007–2008. Longline deployments consisted of a 10–12 km longline anchored to the seabed with 1 m long branchlines with hooks (48,020 total hooks deployed). Frozen Sardinella Sardinella aurita or common cuttlefish Sepia officinalis were used as bait. Longline deployments took place at any time of day and lines were retrieved either immediately, after 1–2 hours, or after >2 hours.

(Summarised by: Katie Sainsbury)