24 June 2005

Circle hooks help save sea turtles

Results from the first large-scale testing of specially designed fishing hooks show that the use of circle hooks can reduce the number of endangered sea turtles killed in long line fishing operations by as much as 90 percent, said WWF.

The results from the one year research project, which involved 115 fishing vessels in Ecuador, were presented at the annual meeting of the Inter-American Tropical Tuna Commission in Lanzarotte, Spain.

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

The results of the study found "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 programme.

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.

So, 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 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.


  • 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 turtle 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: 221–231. Quantifying the effects of fisheries on threatened species: the impact of pelagic longlines on loggerhead and leatherback sea turtles.

    For more information, please contact:

    Monica Echeverria, WWF’s Communications Coordinator for Latin America and the Caribbean, T: +202 778 9626; monica.echeverria@wwfus.org

    Source: WWF


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