Reasons for massive starfish dieoff still unknown

 

Here’s some shocking news: Since last fall, when I first wrote about Pacific sea stars falling victim to a mysterious disease, turning into goo and dying, the aptly-named “starfish wasting syndrome” has not – as scientists hoped – subsided on its own. It’s gotten much, much worse.

How much worse, you ask? Well, from the get-go, this iteration of starfish wasting was more widespread and severe than previous outbreaks, which have historically spiked during warm-water El Niño years and then quickly subsided. By the time it was identified late last summer, the disease had already caused localized die-offs of up to 95 percent of ochre sea stars in Santa Cruz, California, and was spotted as far north as Alaska. Tens of thousands of starfish simply wasted away and died, literally before researchers’ eyes.

Yet it seemed for a while that Washington and Oregon would be spared. This May, just over 1 percent of ochre sea stars in Oregon were affected. But now – a mere four weeks later – an estimated 30 to 50 percent are dying, and scientists predict a 100 percent mortality rate in some places. In parts of Washington’s San Juan Islands, mortality jumped from 10 to 40 percent over the course of a single week in June, and the disease has now been confirmed in more than a dozen species. “This is an unprecedented event,” says Bruce Menge, a marine biologist at Oregon State University. “We’ve never seen anything of this magnitude before.”

An ochre sea star with starfish wasting syndrome turns to mush. Courtesy Elizabeth Cerny-Chipman/Oregon State University

By now, you might well be wondering what’s behind this intertidal horror show. Funny you should ask. Though the outbreak has prompted a slew of research and emergency funding from the National Science Foundation, no one really knows. We’re 11 months into an epidemic that could wreak havoc on entire ecosystems from Mexico to Alaska, and we can’t pin down the cause. It’s like the bubonic plague is striking our oceans, and we’re stuck in the dark ages.