Scientists: Mysterious Pacific Coast Starfish Die-Off Cause Found – KXL

WASHINGTON, DC – Scientists believe they have discovered what is behind the mass die off of starfish along the Pacific coast over the decade.  More than 5 billion starfish are estimated to have died from Mexico to Alaska. The epidemic reportedly continues to devastate more than 20 species. Scientists say the sunflower starfish has been the hardest hit species, losing about 90 percent of its population in the outbreak’s first five years.

“It’s really quite gruesome,” marine disease ecologist Alyssa Gehman at the Hakai Institute in British Columbia, Canada, told the Associated Press.  Gehman, who assisted in determining the cause, also said healthy sea stars have “puffy arms sticking straight out.” But the wasting disease causes them to grow lesions and “then their arms actually fall off.”

Now, evidence points to bacteria that has also infected shellfish.  That is the conclusion of a study published recently in the journal Nature Ecology and Evolution.

The findings “solve a long-standing question about a very serious disease in the ocean,” said Rebecca Vega Thurber, a marine microbiologist at University of California, Santa Barbara, who was not involved in the study, which was more than a decade in the making.

“It’s incredibly difficult to trace the source of so many environmental diseases, especially underwater,” said microbiologist Blake Ushijima of the University of North Carolina, Wilmington, who was not involved in the research. He said the detective work by this team was “really smart and significant.”

Now that scientists know the cause, they have a chance to save starfish.  Those efforts could include relocating healthy starfish, or breeding them in captivity to be transplanted later to areas where almost all the sunflower starfish have vanished.  Scientists may try to determine if some starfish populations have natural immunity, and if treatments like probiotics may help boost immunity to the disease.

Saving starfish is considered important because of their role in the ecosystem.  Healthy starfish, for example, gobble up excess sea urchins, researchers say.

Sunflower sea stars “look sort of innocent when you see them, but they eat almost everything that lives on the bottom of the ocean,” said Gehman. “They’re voracious eaters.”  With many fewer sea stars, the sea urchins that they usually munch on exploded in population – and in turn gobbled up around 95 percent of the kelp forests in Northern California within a decade. These kelp forests provide food and habitat for a wide variety of animals including fish, sea otters, and seals.