According to the World Wildlife Fund (WWF), accidental catch or by-catch is probably the single greatest threat to marine turtles. As many as 200,000 Loggerheads and 50,000 Leatherback Turtles are caught annually by commercial long-line tuna, swordfish, and similar fisheries. WWF has been working with Mustad, the world's largest manufacturer of fishing hooks, to greatly reduce this problem by producing circle hooks for commercial fisheries.
Circle hooks (above, right) can easily be removed and the catch released. It is safer for turtles and other by-catch than the traditional J-hook (above, left) © WWF
Loggerhead turtle - vulnerable to long-line hooks, and critically endangered © WWF
The wandering Albatross is one of the species threatened by accidental drowning on long-lines © RSPB
The circle hook works by only fastening to the side of the mouth, where it can easily be removed and the prey released. The circle hook has proved to be better than the traditionally used 'J' shaped hook, which can be snagged by turtles, leading to suffocation or internal bleeding if swallowed.
It is already forbidden to use anything but circle hooks for commercial line fishing in the United States. Additionally, many sports fishermen use circle hooks to avoid by-catch, particularly when fishing for swordfish, tuna, sailfish, and blue marlin, and species that are normally released after being caught. Mustad is providing WWF with 250,000 circle hooks to be distributed to projects in areas where turtle by-catch presents a serious problem.
As reported in the last issue of Zwazo, traditional hooks and long lines have decimated many species of albatrosses and petrels, which are accidentally killed when they take the baits. So far very little is known about what impact circle hooks might have on reducing seabird by-catch. Some data have been collected in Hawaii, Brazil and South Africa, but sample sizes are currently too small to be conclusive. The view from BirdLife is that there are several ways in which circle hooks could slightly reduce seabird by-catch:
- the hooks are bigger, so may be less likely to be swallowed by seabirds
- the hook is turned inwards, so external snagging on wings or other body parts could be reduced
- for those birds caught during line hauling (as opposed to line setting), there may be better chance of post-release survival with circle hooks rather than J-hooks (as is the case for turtles, sharks, etc).
'It is vital to the survival hopes of many non-target species that ways of reducing unnecessary and wasteful by-catch in our fisheries continue to be explored, promoted and adopted by fisheries managers.'
All seven species of marine turtle Hawksbill, Green, Kemp's Ridley, Olive Ridley, Leatherback, Loggerhead, and Flatback are listed on Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES).
Six of the seven species are listed as Endangered or Critically Endangered because of by-catch, and because of the illegal poaching and sale of turtle shell, eggs, leather, and meat. Hawksbill and Green turtles are known to breed in Seychelles, and Leatherback and Loggerhead turtles are known to use Seychelles waters. "It is vital to the survival hopes of many non-target species that ways of reducing unnecessary and wasteful by-catch in our fisheries continue to be explored, promoted and adopted by fisheries managers."
Turtle campaigning locally
The year 2006 has been declared the Year of the Turtle, by the International Ocean South East Asian Marine (IOSEA). Nature Seychelles has produced two full-colour posters of the Hawksbill and Green Turtles. Each has a message in Creole on the same format as the endemic bird posters we produced previously.
We are also developing a brochure that will be distributed to schools and Wildlife Clubs, with copies also made available to relevant organisations like the Ministry of Environment and Natural Resources and the Seychelles Fishing Authority.