Scientists Finally Identify Bacteria Behind Mysterious Mass Die-Off of 5 Billion Sea Stars

After more than a decade of mystery, scientists say they’ve finally identified what wiped out more than 5 billion ⭐Sea stars along North America’s Pacific coast — one of the largest marine die-offs ever recorded.

According to The Associated Press, the culprit: a bacterium called Vibrio pectenicida, which has also infected shellfish, according to a new study published Monday in Nature Ecology and Evolution.

Starting in 2013, a mysterious sea star wasting disease devastated populations from Mexico to Alaska, destroying more than 20 species. The sunflower sea star — once one of the most common — lost about 90% of its population in the first five years.

“It’s really quite gruesome,” said Alyssa Gehman, a marine disease ecologist at the Hakai Institute in British Columbia, who helped identify the cause. “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.”

The discovery ends years of false leads. Early research suggested a virus might be responsible, but scientists later learned the suspected densovirus was actually harmless to healthy ⭐Sea stars, said Melanie Prentice, co-author of the study.