Efficiency of the circle hook in comparison with J-hook in longline fishery

Tests were conducted aboard pelagic longline vessels in the Bay of Bengal to determine if there were differences in the catch composition, catch rate, hooking position or length frequency of target and bycatch species caught with circle and J-hooks.  Circle hooks caught similar percentages of both target (46.7%) and bycatch (53.3%) species, while J-hooks caught a higher percentage of bycatch (74.5%) species.  Catch rates for the target species were higher for circle hooks (2.2 individuals/1,000 hooks) compared to J-hooks (1.9 individuals/1,000 hooks).  In contrast, catch rates for the bycatch species were higher on J-hooks (5.6 individuals/1,000 hooks) than circle hooks (2.6 individuals/1,000 hooks).  For the target species, swordfish (Xiphias gladius) had the highest catch rates for both hook types but catch rates were slightly higher on circle hooks.  Close to three quarters (73.3%) of fish were hooked in the mouth when circle hooks were used while only half (53%) were hooked in the mouth, and 38% in the digestive system, when J-hooks were used.  Swordfish caught with J-hooks were slightly larger (mode of 250-269 cm) than those caught with circle hooks (mode 210-229 cm).