Pisaster disaster: When starfish wasting disease strikes, there’s only one man to call
Dr. Chris Mah may be the only man in the world who can correctly identify any species of starfish on sight. Growing up in San Francisco on a steady diet of sushi and Japanese monster movies, it was no wonder he was attracted to the weird, slimy invertebrates he plucked from the shores of the Bay. Now based at the Smithsonian in Washington, DC, he’s an internationally recognized marine invertebrate expert who’s identified more than 20 new species. He also maintains the Echinoblog, a strangely entertaining site where starfish are posed next to action figures to show their size, feeding mechanisms are likened to wrestling moves and posts have titles like “Giant Green Brittle Stars of Death! When they Attack!”
So when a diver in Vancouver, British Columbia first noticed scores of dead and dying sunflower stars (Pycnopodia helianthoides) in late August, he snapped photos and sent them to Mah. Mah knew right off the bat what the trouble was: A classic case of Starfish Wasting Syndrome.
Or was it? Starfish Wasting Syndrome had struck the Pacific Coast before, causing mass die-offs of Southern California sea stars in 1983 and again in 1997. Both were during El Niño years, when oceans were slightly warmer, and scientists thought they had the disease pegged. This time, though, there was no sudden warming of the ocean to blame.
The disease was also far more widespread and severe than previous occurrences, causing localized die-offs of 95 percent in Santa Cruz and spreading as far north as Alaska. Mah posted a blog about the new phenomenon, and within weeks, divers and tidepoolers up and down the coast were sharing pictures of sunflower stars, common ochre sea stars (Pisaster ochraceus) and others that seemed to have the same affliction: a white lesion that, within hours or days, spreads and decays the starfish’s tissue, reducing it to a pile of slime.
“The sick ones tend to just fall apart in front of your eyes,” Vancouver Aquarium biologist Jeff Marliave told radio station KUOW. “An arm will actually break off and crawl away. (Then) they turn into goo.”
Pete Raimondi, a professor of ecology and evolutionary biology at the University of California, Santa Cruz, was fresh from a dive in Monterey Bay when I spoke with him earlier this week. Raimondi has been diving in California since the early 1980s and has witnessed Starfish Wasting Syndrome before. This time, it struck so swiftly he could hardly believe his eyes.
“On Oct. 1, everything seemed fine,” he said. “Over the last three or four weeks, there’s been a huge change. A few dives ago we started noticing (starfish) decomposing … Now a couple species are gone (from this area). Just wasted away. We can’t even find them. Others are close, and other (species) are doing just fine.”
Raimondi heads a marine monitoring program that has been collecting data on ecosystems along the U.S. and Canadian coast for over 20 years. Now, he’s dispatched an additional team to “blitz” the coast, trying to pinpoint where the outbreaks are occurring and helping to create a detailed epidemiological map. The hope is that discovering where the disease is striking and perhaps where it started can help scientists figure out what’s causing it.
“We literally know nothing about it,” Mah said. “There’s only one or two (academic) papers. Is it a virus? Is it a bacteria? Is there even one proper cause?”
Raimondi has sent tissue samples to pathologists at Cornell and Brown universities to try to discover the root of the problem. And then, of course, there’s the internet.
Just about every news story that’s covered the disease has spawned comments from readers who fault lingering radiation from the 2011 Fukushima nuclear disaster in Japan. But Mah shoots such theories down, pointing out that Starfish Wasting Syndrome existed decades before the nuclear disaster, and that if radiation were to blame, other kinds of sea life would be affected too. He suggests that a population explosion of sunflower stars over the last couple of years may be partially to blame, allowing the disease to spread more easily, much the same way that dense forests facilitate the spread of pine beetles. Yet it’s too soon to say anything conclusive about the mysterious wasting disease and its effects on biodiversity.
“I don’t think it’s going to be catastrophic,” Raimondi said. “But I think it’s really important. We’re two, maybe three months into this. We may be at the peak or it may just be the onset. There’s no way to tell.”
One thing’s certain: People care about the fate of starfish. Both Mah and Raimondi agree that citizen scientists posting snapshots online are playing an instrumental role in tracking the outbreak.
“It brings to mind an episode of the X-Files,” Mah muses, true to form. “(FBI agent) Mulder depended on these UFO guys to show him where all these lights in the sky are. It’s the same thing: Divers are showing us where these corpses are.”
Krista Langlois is an editorial intern at High Country News. She tweets @KristaLanglois2.