A mysterious disease that has been claiming the lives of sea stars up and down the US, Canadian, and Mexican coasts since last summer has now wiped out as much as 60% of the populations of purple ochre sea stars being watched in Oregon—populations that as of April had seen less than 1% of its numbers affected. Creatures suffering from the "sea star wasting syndrome" first cross their arms, then break out in white lesions that turn into holes, and ultimately disintegrate to the point where their entire arms can turn to goo. And while wasting is not a new occurrence, "usually it's very localized to a single site or single region," which healthy neighboring populations can recolonize, biologist Bruce Menge tells Live Science.
But in this case, the outbreak that began in June in Washington has touched places as distant as Alaska and New Jersey, and it's now hit Oregon, the sole West Coast state that had essentially been unscathed. In May, the Weather Network reported that a bacterial or viral pathogen may be at the root of the die-off, though no definitive cause has been established. What has been established, however, is that 95% of infected sea stars perish. "It's very serious," Menge tells the Weather Network, and he zeroes in on one potential cause for alarm: "Some of the sea stars most heavily affected are keystone predators," which typically feast on the mussels that occupy Oregon's low shores, preventing the mussels' numbers from skyrocketing. The sea stars "influence the whole diversity of life in the intertidal zone."