A comparison of circle hook and J hook performance in a western equatorial Atlantic Ocean pelagic longline fishery

The effect of circle hooks and J-style hooks on the catch composition, catch rates, hooking location and status of release of target and bycatch species were compared on pelagic longline vessels.  There were significant differences in catch rates between the two hook types for bigeye tuna, which had higher catch rates on circle hooks and sailfish, pelagic stingrays, and leatherback sea turtles, which had higher catch rates on J-style hooks.  Survival of bigeye and yellowfin tunas was significantly higher when circle hooks were used and bigeye and yellowfin tunas, swordfish and sailfish had significantly higher external hookings when circle hooks were used.  The results suggests using 18/0 circle hooks with a zero degree offset could increase the survival of bycatch species while having minimal effects on the catches of target species.