Reducing sea turtle interactions in the Hawaii-based longline swordfish fishery

To reduce turtle interactions, regulations for the Hawaii-based longline swordfish fishery required vessels to switch from using a J-shaped hook with squid bait to a wider circle-shaped hook with fish bait. Analyses of observer data showed that, following the introduction of the regulations, significant and large reductions in sea turtle and shark capture rates occurred without compromising target species catches. There was also a highly significant reduction in the proportion of turtles that swallowed hooks and a highly significant increase in the proportion of caught turtles that were released after removal of all terminal tackle. Research suggests that turtles aggregate at foraging grounds and that instituting methods to avoid real-time turtle bycatch hotspots may further reduce turtle interactions.
Field Studies:

Location	Fishing gear	Reduction technique	Bycatch species	Effect on bycatch species	Catch	Effect on target catch	Type
off Hawaii	Hooks-and-Lines	Circle hooks	Sea Turtles	Leatherback turtle capture rates declined by 83% and loggerhead capture rates declined by 90%	Swordfish	Swordfish catch increased by 16%, tuna catch decreased by 50%, and mahi-mahi, opah, and wahoo catch decreased by 34%	In the wild
off Hawaii	Hooks-and-Lines	Fish instead of squid bait	Sharks	Decreased by 36%	Swordfish	Swordfish catch increased by 16%, tuna catch decreased by 50%, and mahi-mahi, opah, and wahoo catch decreased by 34%	In the wild
off Hawaii	Hooks-and-Lines	Circle hooks	Sea Turtles	Highly significant reduction in the proportion of turtles that swallowed hooks	Swordfish	Swordfish catch increased by 16%, tuna catch decreased by 50%, and mahi-mahi, opah, and wahoo catch decreased by 34%	In the wild