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

Authors
Gilman, E., D. Kobayashi, T. Swenarton, N. Brothers, P. Dalzell, and I. Kinan-Kelly
Year
Journal/Publisher Name
Biological Conservation
Volume (Issue #)
139
Page #s
19-28
Contact information
egilman@blueocean.org
Summary
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

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

Study Type
Field study in the wild
Location
off Hawaii
Target catch
Swordfish
Effect on bycatch species
Leatherback turtle capture rates declined by 83% and loggerhead capture rates declined by 90%
Effect on target catch
Swordfish catch increased by 16%, tuna catch decreased by 50%, and mahi-mahi, opah, and wahoo catch decreased by 34%
Bycatch species
Reduction technique
Fishing Gear

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

Study Type
Field study in the wild
Location
off Hawaii
Target catch
Swordfish
Effect on bycatch species
Decreased by 36%
Effect on target catch
Swordfish catch increased by 16%, tuna catch decreased by 50%, and mahi-mahi, opah, and wahoo catch decreased by 34%
Bycatch species
Reduction technique
Fishing Gear

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

Study Type
Field study in the wild
Location
off Hawaii
Target catch
Swordfish
Effect on bycatch species
Highly significant reduction in the proportion of turtles that swallowed hooks
Effect on target catch
Swordfish catch increased by 16%, tuna catch decreased by 50%, and mahi-mahi, opah, and wahoo catch decreased by 34%
Bycatch species
Reduction technique
Fishing Gear