[A Sunflower Sea Star with several arms missing. Photo by Jerry Kirkhart via Flickr & CC 2.0 License.] 

In 2013,  something strange started happening to the starfish, or sea stars, that live along North America’s Pacific Coast. Casual observers began reporting starfish that were “dissolving” or “melting”.

“What you first see is they start getting spots on them,” explains marine veterinarian Joseph “Joe” Gaydos of University of California Davis. “They [the sea stars]  start shrinking, and then legs start falling off…Legs will fall off and then crawl around, so it really is like something out of a horror show.”

In 2014,  researchers were able to identify a viral culprit as the immediate cause of the disintegrating sea stars, but we still know very little about how it spreads or which starfish species are most affected by it.

The dying sea stars that were easiest to spot were the ones that live close to shore.  But no one knew what the mysterious Sea Star Wasting Disease (SSWD) was doing to the sea stars deep underwater and in the open ocean. 

“When the sea star wasting disease hit in the Salish Sea in 2013, my first thought was, ‘Gosh, we have 29 species of sea stars. Who’s going to get hurt?’”  Gaydos told me over the phone. 

Luckily, the Salish Sea, an area which includes Puget Sound in Washington State and the Gulf Islands in British Columbia, Canada,  is home to an organization called REEF. Since 2006, REEF has been training amateur divers to count the organisms they see, and over 8,000 of those dives have included sea star counts. 

Gaydos and his colleagues, led by Diego Montecino-Latorre, analyzed the data from REEF’s dives. They also supplemented the REEF data by systematically criss-crossing the Salish Sea’s basins, counting the starfish they saw.

And the data tell a story of devastation. At least, for some of the sea stars.  Continue reading “How 600 Citizens Helped to Document an Underwater Epidemic” »