Involved countries working with the program adopt the mechanism

Ports where we work

Circle hooks in tuna fisheries not only reduce marine turtle bycatch, but they also maintain, and possibly even increase, target catch rates.
For the mahi mahi fishery, circle hooks still reduce turtle bycatch, but target catches are slightly reduced. In this instance, we need to closely >examine why this is so, and make the necessary modification to the shape of the hook.

Our experiments have shown that in the tuna fishery, circle hooks have reduced turtle bycatch by as much as 60% with a smaller but still important reduction of 26% in the mahi mahi fishery.

Fortunately, if a "circle" hook does happen to catch a sea turtle it will do so (more often) by the mouth, avoiding fatal injuries and improving survival chances of sea turtles.
 / ©: Carlos Miguel Imbach
Fishermen works with a "circle" hook longline.
© Carlos Miguel Imbach
Experimental statistics after 4 years of trials (2004 to 2007)


Number of Fishing trips


Number of longline sets

Number of times hooks have been used


Number of vessels involved








*a ‘set’ is each time a fisher uses his longline.

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