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Year-long Study Shows Circle Hooks Help Save Sea Turtles

Washington, DC - Preliminary results from the first large-scale testing of specially designed fishing hooks are being presented at the annual meeting of the Inter-American Tropical Tuna Commission in Lanzarotte, Spain. Thus far, the results indicate they can reduce the number of endangered sea turtles killed in long line fishing operations by as much as 90 percent, World Wildlife Fund said today.

Incidental death -- as a result of traditional long line fishing operations -- is one of the main reasons for the precipitous decline of loggerhead, and of the giant leatherback turtles, whose numbers in the Eastern Pacific have plunged by more than 90 percent over the past 20 years.

But the results of a year-long study involving 115 Ecuadorian fishing vessels found that this "bycatch" was dramatically reduced when the boats replaced their traditional 'J' shaped hooks with specially designed circle hooks. "This is a win-win situation. We were looking for a way to save the turtles without putting the fishermen out of business. The preliminary results indicate we've found it. Circle hooks seem to be an effective new tool in our efforts to address this urgent conservation problem," said Moises Mug, Fisheries Coordinator for WWF's Latin America and Caribbean program.

Over the past year, Ecuador's tuna and mahi-mahi fisheries each tested one large and one small circle hook. Larger devices reduced the number of sea turtles that got hooked by 88 percent in the tuna fishery and 37 percent in the mahi-mahi fishery. The smaller hooks proved less effective, but still reduced bycatch rates by 44 and 16 percent, respectively.

"However, we believe mortality rates were reduced further by the fact that, because of their shape, circle hooks were less likely than J hooks to get swallowed by turtles," said Kim Davis, deputy Director of WWF-US's marine program. "The hookings generally were in the lip area, with a greater chance of the turtle being released without serious injury."

When the survival rate for hooked turtles was factored into the results, the researchers estimated that the circle hooks reduced sea turtle mortality by 63 to 93 percent in the tuna fishery and 41 to 93 percent in the mahi-mahi fishery, depending on the size of the hook used.

Also encouraging was the fact that catch rates for tuna were almost identical regardless of whether circle or J hooks were used. The catch rate was lower in the mahi-mahi fishery, however, and researchers said further refinement of fishing gear and better training of fishermen would be needed to close the gap.

The research was developed with the participation of many local stakeholders, government, industry, fishers unions and co-operatives, and environmental groups. "The Ecuadorian government and fishermen deserve a lot or credit for being leaders in this effort," said Mug. "Their willingness to test these hooks is motivation to other nations across the Pacific. The tests are already being expanded to involve fishing fleets from 10 other Pacific Ocean nations with support from WWF and its partners. We congratulate the fishermen and government of Ecuador, the Inter-American Tropical Tuna Commission and other partners who helped to make the initial tests a success," Mug said.

Fishermen attended training workshops and onboard monitors helped to collect the data. The National Oceanic and Atmospheric Administration (NOAA) provided technical assistance, while financial and logistical support was provided by the Ecuadorian government and local fishing groups, WWF, the Western Pacific Fishery Management Council and The Ocean Conservancy.



  • WWF is now conducting or supporting turtle conservation work in 45 countries and is engaged in every major international turtle conservation policy discussion underway. In the eastern Pacific, WWF has a long history of constructive engagement in the bycatch reduction work of IATTC, and is now formally represented on the Commission. In the western Pacific, WWF has helped shape the new Western and Central Pacific Fisheries Commission policies, which will be important in reducing leatherback bycatch in longline fisheries.


  • Scientists estimate that as many as 200,000 loggerheads and 50,000 leatherbacks are caught annually by commercial long-line tuna, swordfish, and other fisheries. See: Rebecca L. Lewison, Sloan A.Freeman and Larry B. Crowder, Ecology Letters, (2004) 7: 221231. Quantifying the effects of fisheries on threatened species: the impact of pelagic longlines on loggerhead and leatherback sea turtles.


  • Maps and photos available upon request.