‘Weak’ hooks protect bluefin tuna but allow yellowfin and swordfish catch

07 Apr 2011
James Barbour, NOAA fishing gear researcher, holds a swordfish. Credit: NOAA

James Barbour, NOAA fishing gear researcher, holds a swordfish. Credit: NOAA

From 5 May, longliners who fish for yellowfin tuna, swordfish and other species in the Gulf of Mexico will have to use a new ‘weak hook’, designed to reduce the incidental catch of Atlantic bluefin tuna.

Directed fishing for bluefin tuna in the Gulf has been prohibited since the early 1980s, however bluefin are caught incidentally by longline fishermen who target other species. The Gulf of Mexico is the only known spawning area for the western stock of Atlantic bluefin tuna, a historically overfished species. Many bluefin die from the stress endured in this incidental capture in warm water even if fishermen release them.

“NOAA worked with longline fishermen from the Gulf to test the weak hook carefully over the last three years,” said Eric Schwaab, assistant NOAA administrator for NOAA’s Fisheries Service. “Our cooperative scientific research with fishermen is showing that this new technology can protect bluefin tuna in the Gulf while still allowing fishermen to target yellowfin tuna and swordfish.”

The weak hook is a circular hook constructed of thin gauge wire, and is designed to straighten when a large fish, such as bluefin tuna, is hooked, releasing it but holding on to smaller fish. The average size of bluefin tuna landed in the Gulf of Mexico longline fishery is 485 pounds, while the average for yellowfin tuna is about 86 pounds. 

Research showed that the weak hook could result in some reductions in target catch while some longline fishermen have reported weak hooks did not hurt their businesses.

“During our tests, we used regular hooks for half our hooks and half were the new weak hooks,” said Capt. Mike Carden, a longline fisherman from Panama City, Fla. who took part in the cooperative research. “We were so happy with the weak hooks we quit using the heavy hooks. The weak hook releases fish we don’t want to catch. Because it’s smaller and lighter, we catch more yellowfin tuna on the weak hook. There’s several of us who have gone to the weak hook.”

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