Other efforts missed the real killer because researchers studied tissue samples of dead sea stars that no longer contained the bodily fluid that surrounds the organs.
But the latest study includes detailed analysis of this fluid, called coelomic fluid, where the bacteria Vibrio pectenicida were found.
“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 better shot at intervening to help sea stars.
Prentice said that scientists could potentially now test which of the remaining sea stars are still healthy — and consider whether to relocate them, or breed them in captivity to later transplant them to areas that have lost almost all their sunflower sea stars.
Scientists may also test if some populations have natural immunity, and if treatments like probiotics may help boost immunity to the disease.
Such recovery work is not only important for sea stars, but for entire Pacific ecosystems because healthy starfish 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% of the kelp forest s 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.
Researchers hope the new findings will allow them to restore sea star populations — and regrow the kelp forests that Thurber compares to “the rainforests of the ocean.”