By NATALIE MARTIN

As scientists work to understand what’s killing off millions of starfish up and down the West Coast, a small group of islanders is joining a regional effort to help monitor the mystery epidemic.

On a chilly evening last week, islander Jeff Adams, a marine water quality specialist with Washington Sea Grant and a local beach naturalist, led about a dozen people under the north-end ferry dock at low tide. Adams was training the group to identify starfish affected by what scientists are calling sea star wasting syndrome.

While pilings under the north-end dock are normally covered with brightly colored starfish — also called sea stars — these days fewer than a quarter of the normal population remains, Adams said. Many of the remaining sea stars are twisted, oozing, missing limbs or slowly falling off the pilings.

“On the scientist side, I can be okay with natural correction,” Adams said in an interview. “But as a naturalist, these are some of the things I love to play with on the beach and show people on the beach. … It’s sad.”

Sea star wasting syndrome — characterized by the way affected starfish seem to tear apart or waste away — hit local waters last year, leaving marine scientists scrambling to determine the cause of the unusual and quickly spreading disease.

“Sea stars are pretty much iconic of our beaches,” said Kelly Keenan, a Vashon Beach Naturalist who attended the recent training. “With them all of the sudden disappearing and wasting away, it’s really quite sad and devastating to see.”

Keenan is now one of a small group from Vashon who will monitor sea stars periodically at locations around the island, reporting what they see to the Multi-Agency Rocky Intertidal Network (MARINe), a consortium of agencies, universities and private groups working to study the wasting syndrome.

MARINe, which has monitored intertidal sea life up and down the West Coast for years, recently received a grant from Washington Sea Grant to implement a citizen program specifically to collect data on sea stars. Volunteer groups are now forming throughout the Puget Sound and on the Washington and Oregon coasts.

“So far in Washington there’s a lot of interest,” said Melissa Miner, a University of California, Santa Cruz research associate based in Bellingham who is heading up the effort for MARINe. “It’s going to be a pretty big thing to have citizen science work as part of the monitoring work we do.”

Sea star wasting syndrome was first seen on the Olympic Peninsula last summer, and since then has been identified in sea star populations from Alaska to southern California. An interactive map put online by MARINe shows the disease has hit sea stars throughout the Puget Sound, from Bellingham to Tacoma.

The wasting syndrome typically spreads through populations quickly, causing sea stars to first go limp and often develop lesions. Arms then begin to rot or detach and crawl away before the entire sea star deteriorates and dies, sometimes within a matter of days.

Researchers have been studying the epidemic for months, Miner said, but are still puzzled as to the cause. Similar diseases have broken out in the past, but never on this large a scale and never lasting this long, she said.

“This event is really unprecedented in the fact that we’re seeing it on such a large geographic scale,” Miner said.

Symptoms of the wasting syndrome are the same as those exhibited by sea stars in distress, complicating the picture for researchers. Scientists are considering a variety of causes, including warm water temperatures, pollution, bacteria or a virus. Research has also shown that the disease’s spread is patchy, affecting some areas and not others.

“It could likely be a combination of factors exacerbated by an environmental condition,” Miner said, adding that the new volunteer effort will provide data from even more beaches, hopefully providing further clues as to the root of the problem.

“There are a number of things that could cause wasting to be more severe in some places than others, so it really will help us put together the picture of where we’re seeing it and where we’re not,” Miner said.

So far the disease has affected a dozen species of sea stars, causing large-scale die-offs in many places. Among the hardest hit are the ochre star — the iconic orange and purple stars often seen in Washington waters — and the large, multi-armed sunflower star.

On Vashon, many started noticing diseased sea stars late last year. At the Vashon Beach Naturalists’ annual New Year’s Eve nighttime beach walk, the rocky north-end beach was strewn with dead sea stars and limbs. Keenan, who also took a nighttime beach walk at the beginning of December, said the scene was ever worse then.

“It was total annihilation. Legs were pulling off from each other and they were everywhere. It was so, so sad,” she said.

Those recently trained by Adams to identify sea star species, affected sea stars and what phase of the disease they are in will now be responsible for monitoring a site they selected, checking the specific plot once a month for both healthy and sick creatures.

Miner said she hopes some volunteers will stick with the program for years, so MARINe can collect data as the syndrome hits some areas and as sea stars eventually return.

While sea star populations are expected to recover, she said, those in the scientific community are concerned about how the mass death of sea stars could impact the underwater ecosystem. Sea stars are considered a critical keystone species, feeding on many other organisms and keeping intertidal communities in balance. Its unknown how long it could take sea star populations to return to normal.

“It would be great to have this long-term information,” Miner said.

Adams, who recently led trainings on the Kitsap Peninsula and in Seattle as well, said that while it’s been hard to watch the wasting syndrome hit local beaches, he hopes the citizen science effort will play a part in narrowing down the cause of the baffling epidemic.

“This large-scale community engagement of citizen scientists could really help us understand it,” he said.