Two years ago, scientists were baffled by a massive sea star die-off off the coast of California. A viral disease, exacerbated by the effects of global warming, was found to be the culprit, and millions of tiny sea stars died as a result. Marine biologists were concerned that the die-off could wipe out the marine creatures entirely, but now there is some good news out of Oregon and California. Researchers at Oregon State University have compiled new data that shows unprecedented numbers of baby sea stars survived the summer and winter of 2015 – the tail end of the viral outbreak – proving that nature often finds a way.
Over the course of several months back in 2014, scientists closely studied the dying sea stars to isolate the problem. The die-off was linked to a virus, which caused the bodies of the marine creatures to pull apart and eventually disintegrate. Researchers identified the disease as Sea Star Associated Densovirus (SSaDV), a pathogen known to be present in the ocean for more than 70 years, but never before seen in such a massive outbreak.
OSU researchers were more than surprised by the new data. “When we looked at the settlement of the larval sea stars on rocks in 2014 during the epidemic, it was the same or maybe even a bit lower than previous years,” said marine biology professor Bruce Menge in a statement. “But a few months later, the number of juveniles was off the charts – higher than we’d ever seen – as much as 300 times normal.”
Although the virus has been named, the exact cause for the mass die-off is still unknown. Some researchers suspect global warming created optimal conditions for the virus to reproduce and spread, while others have suggested a viral mutation might have occurred. Continued research aims to unravel the mystery, as scientists watch global sea star populations closely to find out what happens next.