Modify number of hooks between floats on longlines
Overall effectiveness category Awaiting assessment
Number of studies: 1
Background information and definitions
Using more floats on a longline per hook alters the profile of the longline in the water, which may reduce the opportunities for sea turtles swimming below the surface to become entangled in the line or caught on the hooks.
Supporting evidence from individual studies
A replicated study in 1992–2015 in pelagic longline fisheries in the Atlantic and North Pacific (Swimmer et al. 2017) found that using fewer hooks between floats on a longline did not reduce turtle by-catch in the Pacific but had mixed effects in the Atlantic depending on the species. All data presented as statistical model results. In the Pacific, by-catch of leatherback Dermochelys coriacea and loggerhead Caretta caretta turtles was not affected by the number of hooks between floats. In the Atlantic, the chance of catching leatherback turtles was lower with fewer hooks between floats, whereas loggerheads were less likely to be caught when there were fewer (<3 hooks) or more (>5 hooks) hooks between floats (see paper for details). Pelagic Observer Program data from (1992–2015) was used to determine the number of turtles caught/1,000 hooks, and variation in the number of hooks between floats (majority were 3–5 or 4–5 hooks/float) was used to test its effect on bycatch.Study and other actions tested