![]() ![]() Local and regional agreements, however, have fewer stakeholders-speeding up the adoption of conservation protections. Paradoxically, that vulnerability may also bring benefits, by intensifying pressure on regional and local governments to conserve mantas on their own.Ĭurrently, oceanic mantas are protected mainly by two international agreements: CITES, which forbids the international trade of wild manta-based products, and the Convention on Migratory Species, which provides a framework for international agreements on manta conservation.īoth treaties have had their successes, says Stewart, but they are difficult to enforce because of the large numbers of countries involved. “But if there are these very local, isolated subpopulations, then you’re talking about removing half of the population in a year.” “If you had a fishery that was drawing from the entire population of Indo-Pacific mantas, then 10 a hundred mantas a year wouldn’t be a huge number, necessarily,” says Stewart. Manta rays are frequently caught as bycatch and are hunted for their gill plates, a popular ingredient in traditional Chinese medicine. Protecting the Gentle GiantsĬouturier and Stewart say that the findings have major conservation implications for the species, which is currently listed as vulnerable on the IUCN Red List. “The results are surprising, especially when considering the mantas off Mexico that the overlap between populations isn’t greater,” says Lydie Couturier, a manta expert at France’s Institut Universitaire Européen de la Mer who wasn’t involved with the study. In Mexico, for instance, mantas tagged near the Revillagigedo Islands-some 373 miles (600 kilometers) off the country’s Pacific coast-never ventured to the coast, and vice versa.Īnd when the researchers analyzed tiny muscle samples taken from each tagged manta, they found that the mantas in each location had their own genetic and dietary quirks-shooting down the idea that they regularly traveled and mixed with other populations. The tracking data, published Monday in Biological Conservation, indicated that 95 percent of the time, the manta rays at each site stayed in patches of ocean as small as 140 miles (220 kilometers) across and rarely if ever journeyed outside of them. On the contrary, they seemed to prefer a short commute. ![]() (Stewart’s work was supported in part by the National Geographic Society/Waitt Grants Program.)īut when Stewart and his colleagues used satellite tags to track 18 manta rays at sites in Mexico and Indonesia for up to six months at a time, they found that manta rays were far from long-distance travelers. student at the Scripps Institution of Oceanography in San Diego. “We sort of assumed that they were behaving the same way that other large pelagic species do,” says lead author Josh Stewart, a Ph.D. Previous studies had even documented individual manta rays traveling hundreds of miles at a time. Scientists had long thought that oceanic manta rays migrated thousands of miles around the world to follow shifts in the distribution of their food, similar to the movements of other pelagic, or open-ocean, filter feeders such as baleen whales and whale sharks. They filter their food out of the water, snacking on plankton, fish eggs, krill, and occasionally small fish. The findings, based on years of tracking data, tissue samples, and genetic tests, are the latest to overturn long-held ideas about how the giant, mysterious fish eke out a living-and how they should be protected from overfishing.īigger than their reef-dwelling relatives, oceanic manta rays ( Manta birostris) grow up to 23 feet (7 meters) wide and weigh up to 4,440 pounds (2 metric tons). ![]() It turns out that humans aren’t the only species weary of long commutes: A new study reveals that manta rays living in the open ocean prefer staying close to home, rather than migrating over long distances. Scientists have found that oceanic manta rays (Manta birostris) usually live their lives in distinct, local subpopulations, changing how conservationists approach protecting the mysterious fish species. Michael Greshko for National Geographic on the migration habits of the majestic manta ray. Our eco-friendly manta ray and snorkel tours offer one of the best tourist experiences on the Big Island. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |