The mass die-off of starfish off the West Coast is becoming a little less mysterious: Scientists say the starfish, also known as sea stars, fell prey to a one-two punch of virus infection plus unusually warm sea water.
The die-off started in 2013, reached a peak in 2014 and continued last year. Infected sea stars developed lesions that gradually dissolved the creatures from the outside, causing the arms to break away and leaving only whitened piles of starfish goop.
The outbreak has virtually wiped out ochre stars in the coastal waters of Puget Sound, the San Juan Islands and the Olympic Peninsula. More than 20 other species have suffered from Mexico all the way north to Alaska.
In a study published Feb. 15 by the Philosophical Transactions of the Royal Society B, scientists concentrated on what happened to the ochre stars. They already knew that the sea star wasting disease was linked to a densovirus – a pathogen that the scientists say apparently caused more limited outbreaks of the disease decades earlier. But what made the virus more virulent this time?