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: 

2007

Journal/Publisher Name: 

Biological Conservation

Publisher Address: 

Elsevier Ltd. P.O. Box 211 1000 AE Amsterdam The Netherlands

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.

Link: 

http://tinyurl.com/6ptya6

Field Studies

Location Fishing Gear Reduction Technique Bycatch Species Effect on Bycatch Species Catch Effect on Target Catch Type Edit link
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% Field study in the wild
off Hawaii Hooks-and-Lines Alternative 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% Field study 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% Field study in the wild