Sea stars, also called starfish, are being wiped out on a wide scale all along the West Coast. The epidemic, called sea star wasting syndrome, was first discovered off the coast of Washington in June 2013 and has since spread south to San Diego and north to Alaska, according to researchers with the Department of Ecology & Evolutionary Biology at UC Santa Cruz.
"There are very few spots where we aren’t seeing wasting disease happening on at least some level of impact," said Melissa Miner, a researcher at UC Santa Cruz who's tracking the disease. "This is unprecedented."
The disease, which starts as a lesion that rapidly dissolves the colorful intertidal species, could be caused by a viral pathogen, compounded by warming waters, research suggests.
Wasting syndrome has happened before, but on a much smaller and more localized scale. The last significant outbreak was in 1983 and 1984 during an El Niño year when the water was warm.
"This is different from previous wasting events in that it hasn’t been strictly tied to warm temperatures," Miner said. "But it definitely seems to be a factor in some areas."
The progression is concerning, Miner added.
"We’re seeing it affect areas that we maybe saw 1 to 2 percent of the population affected last year at this time,” Miner said. “Now some of those areas are experiencing significant die-offs — 95 percent of the sea stars have now died. So it’s a big deal."
The natural predators feed on mussels, clams and other inter-tidal species. Miner said the impact on the intertidal ecosystem could be dramatic.
"This is kind of a coast-wide test of that idea that these stars, at least the ochre stars that we see in the intertidal, are keystone predators and have a significant impact on other species," Miner said.
At least 10 species of sea stars have been affected by the disease, Miner said. The hardest hit is the ochre star, commonly found near La Jolla.
