Half of endangered turtles snared each year

日期:2019-04-04 06:11:03 作者:东郭噘 阅读:

By Will Knight, Seattle (Image: Catherine McClellan) Loggerhead and leatherback turtles have only a 50 per cent chance of avoiding being accidentally snared by a deep-sea fishing line each year, a new study has revealed. This rate of capture of the endangered turtles is unsustainable, say the researchers. They are calling for the creation of “ocean wildlife reserves” maintained by tracking the turtles using satellite transmitters. Longline fishermen hunting tuna or swordfish regularly hook turtles by accident. Although turtles often hunt for food in fishing areas, until now there has been little effort to quantify the problem of so-called “bycatch”. Rebecca Lewison, Sloan Freeman and Larry Crowder of Duke University Marine Laboratory performed a survey of international turtle bycatch reports. They estimate that more than 200,000 loggerheads and 50,000 leatherbacks were accidentally caught in fishing gear worldwide during 2000. Many encounters are fatal for the turtles that swallow the fishermen’s hooks. And both loggerhead and leatherback turtle populations have already fallen by 80 to 90 per cent over the past decade as a result of habitat loss, egg poaching and predation. But the researchers believe the endangered turtles could be protected within oceanic wildlife reserves. As the turtles’ habitats are moveable, these reserves would have to move with them. The turtles follow ocean upwellings, which attract their prey, as well as the borders between warm and cold water. Ocean reserves could, however, be maintained by tracking the turtles with satellite transmitters, the researchers say. The team is already tagging turtles in order to learn more about their migrations. “In a terrestrial system, you can just draw a boundary around an important place and you have a park – in the open ocean it’s different. The habitats are 3-D and moving,” says Crowder. Graeme Hays, at the University of Wales in Swansea, UK, has also used satellite transmitters to track leatherback turtles. He says the technology has revolutionised research in this area. “Tracking technology has really come of age in the last few years,” Hays told New Scientist. “Satellite tags allow animals to be followed for a year or more and give information on the dive profiles as well as temperature. Over the last couple of years we have followed leatherback turtles wandering around the Atlantic and diving to great depths.” The Duke University team’s work was presented on Thursday at the annual meeting of the American Association for the Advancement of Science meeting in Seattle, Washington. The research will also be appear in the March issue of the journal Ecology Letters. More on these topics: