An eco-friendly way to reduce shark attacks

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An eco-friendly way to reduce shark attacks

Last month, a great white shark nearly killed a surfer off the California coast. Stopping such attacks is tricky: Slaying sharks angers environmentalists, and, according to research, it doesn’t actually reduce the attack rates. Shark nets, meanwhile, kill large numbers of by-catch, such as dolphins, seals, manatees, rays, turtles, and birds. So officials in Recife, Brazil, sought another solution to address the abnormally high numbers of shark attacks—55 incidents resulting in 19 deaths between 1992 and 2011—along a 20-kilometer stretch of the country’s shoreline. In May 2004, the newly created Shark Monitoring Program of Recife installed nearly two dozen drumlines and two longlines—two types of specialized fishing gear—with hooks sized to target seven potentially aggressive shark species: tiger, bull (pictured), blacktip, silky, Caribbean reef, scalloped hammerhead, and great hammerhead. When caught, fishermen hauled these sharks onboard and released them away from swimmers and surfers. Although these species accounted for just 7% of overall catch, most were tiger and bull sharks, the most likely culprits in the attacks. Marine catfish predominated the by-catch, along with snappers, moray eels, groupers, nurse sharks, blacknose sharks, and stingrays, but only 22% of this by-catch died and virtually no endangered species were killed. Over the initiative’s 8 years, shark attacks declined 97%, compared with the years before the program began and during the five intervals when insufficient funding suspended the program, researchers report this month in Animal Conservation. This method is labor-intensive and costly when scaled up, but compared with other tactics, it has the lowest ecological impact—other than doing nothing—while reducing shark bites and protecting endangered species, the researchers say.

Posted in Plants & Animals