Circle or C-hooks vs. traditional J-hooks of longline tuna fishing boat of Nutrindo Freshfood International, Sulawesi, Indonesia, October 2009. Changing from the classic J hook to C hooks can dramatically reduce incidental catch or by-catch of marine turtles by as much as 90%, without affecting fishing efficiency. WWF is working with the Inter-American Tropical Tuna Commission (IATTC) and other partners to introduce the circle hooks, which are much less likely to be swallowed by turtles. Swallowing can result in suffocation or internal bleeding. . NOT AVAILABLE FOR MAGAZINE USE IN GERMAN-SPEAKING COUNTRIES UNTIL 1ST JULY 2013.