Marine Turtle Encounters in the Surface Longline Fishery in North Atlantic Areas: 10-30 degrees N / 15-35 degrees W

This paper describes encounters of five species of marine turtles (C. caretta, D. coriacea, L. olivacea, L. kempii, C. mydas) observed during surface longline fishery in North Atlantic areas (10º-30º N / 15º-35º W) in the 1997-2012 period. A total of 544982 hooks were analyzed; 7.5% came from an experimental cruise which had purposely selected this zone to test the effect of different hook and bait types on by-catch rates of marine turtles. The remainder observations were obtained during routine commercial fishing operations. A total of 438 encounters with marine turtles were recorded over the course of these years, either because the animals bit the bait-hook or because they became entangled in the branchlines. Of these, 89% were released alive. The interaction and mortality rates for species, areas and years combined were 8.0e-04 and 9.0e-05 individuals per hook, respectively. These rates were, however, lower when only recordings from regular commercial fishing were considered. It should not be assumed that the resulting rates are representative of or can be extrapolated to other fishing zones.