Dear EarthTalk: What is the status of sharks around the world? I see occasional stories about sharks attacking humans, but on balance aren't we a lot more brutal to them then they are to us?




"" Pam Hitschler, Radnor, PA.




It's true that humans do a lot more damage to shark populations than vice versa. Marine biologists report that sharks are in rapid decline around the world. In the North Atlantic Ocean, shark populations have declined more than 50 percent over the past 20 years alone, with some species now nearing extinction.




Experts see the primary cause as overfishing, which depletes sharks as well as their prey. Sharks are especially vulnerable to illegal "longlines" (fishing nets strung across dozens if not hundreds of miles of ocean), where they get inadvertently snared along with the tuna and swordfish fishermen intend to catch.




Rising demand for shark fin soup in Asia also is contributing to the demise of sharks. According to a report by Wildaid, shark fins are among the most expensive seafood products in the world, selling for some $700 per kilogram on the Hong Kong market. With prices like that, many longline fishermen, who are already operating illegally, are happy to augment their incomes by "finning" a few sharks along the way. (Finning is the practice of removing a fin from a shark and discarding the rest of the carcass at sea.)




Often, threatened wildlife species manage to maintain their numbers in spite of excessive human predation. But sharks face an especially uphill battle, says renowned shark expert Ransom Myers, because they "take a long time to mature and have relatively few babies."




So what is being done to save sharks? In the U.S., the Magnuson-Stevens Fishery Conservation Act is the primary law that oversees the conservation of U.S. fisheries and has established various management regulations for 39 species of sharks in the Atlantic Ocean, Caribbean Sea and Gulf of Mexico. It outlaws finning if the carcass is discarded but not if the rest of carcass is kept, clearly an unfortunate loophole.




The U.S. also helped develop a United Nations Food and Agriculture Organization treaty (the International Plan of Action for the Conservation and Management of Sharks) whereby 87 countries agreed to develop their own plans for the conservation of sharks. However, only two countries""the U.S. and Australia""have lived up to the agreement. The U.S. plan is administered by the National Oceanic and Atmospheric Administration, which has been working with regional fisheries authorities to make sure fishermen are sticking to cautiously low quotas regarding the number of sharks they are allowed to catch.




What can consumers do to save the sharks?




The Monterey Bay Aquarium in Monterey, Calif., urges consumers to avoid all shark products, not just on restaurant menus but also all souvenirs such as jaws and teeth, and shark-cartilage pills, which have been touted as cancer cures but which have been proven to be completely ineffective and are now widely considered a scam. The aquarium also encourages consumers to support with their pocketbooks conservation groups working to protect sharks and oceans, and specifically those working to set aside marine reserves that are off-limits to fishing.




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