Worrisome! From Alaska to Mexico—and all along the B.C. coast—an iconic animal is disappearing. For reasons that remain baffling to scientists, starfish are dying by the millions, in the grips of a mysterious wasting disease that dissolves their bodies into goo. “I’d do beach walks along a 50-m stretch of shoreline, and count 500 or 1,000 of them,” says Chris Harley, a marine ecologist at the University of British Columbia who’s been monitoring sea stars (as scientists call them) for nearly two decades at sites around Vancouver, West Vancouver and White Rock. Revisiting one of these sites recently, he found a single sea star. The Vancouver Aquarium, which has been tracking the outbreak of sea-star wasting syndrome, warns that the B.C. creatures are experiencing a “mass mortality event,” with some species like the big sunflower stars (which Harley calls “glorious things the size of manhole covers”) particularly affected. On June 4, an Oregon State University (OSU) team warned of an “epidemic of historic magnitude” that threatens to wipe out the state’s entire population of purple ochre sea stars: in the intertidal zone, which is covered by water at high tide and uncovered at low, between 30 to 50 per cent of the species has the disease. “We have no clue what’s causing this,” admitted OSU marine biologist Bruce Menge, not to mention how long it will go on. Sick sea stars appear deflated, like they’re “rotting away,” says Pete Raimondi of the University of California at Santa Cruz. “They start to curl up, and then jettison their arms,” Harley explains. “The arms crawl away from the body.” Depending on the hardiness of the species, the star can last up to a few weeks, or die within a day or two. Raimondi says some sea stars simply rot in place, leaving a ghostly imprint built out of bacteria and nothing more. “It’s very creepy looking.”
Posted on: Mon, 16 Jun 2014 13:56:00 +0000
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