Scientists are struggling to find the trigger for a disease that appears to be ravaging starfish in record numbers along the U.S. West Coast, causing the sea creatures to lose their limbs and turn to slime in a matter of days.

 

Marine biologists and ecologists will launch an extensive survey this week along the coasts of California, Washington state and Oregon to determine the reach and source of the deadly syndrome, known as "star wasting disease."

 

Signs of sea star wasting syndrome typically begin with white lesions on the arms of the starfish that spread inward, causing the entire animal to disintegrate in less than a week, according to a report by the Pacific Rocky Intertidal Monitoring Program at the University of California at Santa Cruz.

 

Starfish have suffered from the syndrome on and off for decades but have usually been reported in small numbers, isolated to Southern California and linked to a rise in seawater temperatures, which is not the case this time.

 

Since June, wasting sea stars have been found in dozens of coastal sites ranging from southeast Alaska to Orange County, California, and the mortality rates have been higher than ever seen before, Raimondi said. In one surveyed tide pool in Santa Cruz during the current outbreak, 90 to 95 percent of hundreds of starfish were killed by the disease.

 

The syndrome primarily affects the mussel-eating Pisaster ochraceus, a large purple and orange starfish, but at least 10 species of sea stars have shown signs of the disease since June.

 

If the numbers of Pisaster ochraceus begin to decrease, mussels could crowd the ocean, disrupting biodiversity.

 

In addition to on-site sampling, scientists in the coming months will use an interactive map to spot starfish wasting location patterns and help identify a driver for the disease.