Sea stars struggling to recover from wasting epidemic - Monterey Herald

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Dazzling, beautiful and bold, sea stars once painted the waters of the Central Coast in a kaleidoscope of shapes and color.

Though some sea stars are recovering from the 2013 wasting epidemic, others, like Monterey Bay’s once-abundant sunflower star, may never be coming back, say sea star experts.

“What we found when the epidemic hit is that there were definite winners and losers,” said Joe Gaydos, Science Director for the marine conservation program SeaDoc Society. Of the more than 2,000 species of sea stars, the winners seem to be the rarer species. “The losers were a few of the most common ones, the highest density ones, like the orange, purple and brown ones, the ochre stars you see at the beach. They just got whacked.”

The other species that took a big hit are the sunflower stars, 3-and-a-half foot squishy giants which were once as common in subtidal waters as ochre stars were along the beach. While Gaydos is optimistic that some stars, like the ochre star, will recover, his outlook for sunflower stars is grim – “We don’t see any evidence of recovery.”

Sea star wasting syndrome describes a number of symptoms that generally result in sea star arms ripping off the body and the flesh decaying into a goopy mess. Sarah Gravem, Oregon State University marine ecologist, described the 2013 wasting event as “a disease that was super deadly and affected lots of species, wiped out entire populations, and spread throughout the entire continent in a matter of years.”

Researchers still don’t know the exact cause of the wasting disease, but Gravem said it was likely the combination of a virus, microbiome imbalance, and a number of climate-change-related shifts in the ocean, like warming waters and algae blooms. As Sara Hamilton, marine ecologist at Oregon State University, summed up, “when the temperature is warmer, the wasting is worse.”

The Ochre stars, which come in orange, purple and brown color variations, were the hardest hit of the intertidal stars by the wasting syndrome. (Joe Gaydos — SeaDoc Society)

In Monterey Bay, both ochre stars and sunflower stars were abundant before the wasting. If you’ve ever been to a tidepool on the Central Coast in the hopes of gently stroking (not poking) a starfish, chances are it was an ochre star. Once very common tidepool residents, ochre stars were hit hard along the coast of southern and central California during the 2013 wasting epidemic. Though it’s rare to see them along the Central Coast these days, Gravem said there are still some around. Up in Northern California and Washington, ochre stars had a big crash but have since had a comeback and they may recover here, too.

Sunflower stars are another story. “We haven’t seen one in California since 2017,” said Hamilton. “We’ve only seen a handful in Oregon since 2016. If you see one, please tell us.”

If you’ve ever been to a tidepool on the Central Coast in the hopes of gently stroking a starfish, chances are it was an ochre star. Unfortunately, its population has shrunk considerably in the wake of the wasting disease. (Joe Gaydos — SeaDoc Society)

Sunflower stars live in kelp forests on the Pacific Coast from Baja California up through Alaska, though they’re less common south of Monterey Bay. While many stars, like ochre stars, eat their prey by throwing up their stomachs onto their targets and then slurping back up the digested victim, sunflower stars, which are voracious predators, chase down their prey at speeds up to a meter per minute and chomp their prey whole. Sunflower stars eat the creatures, such as sea urchins, who feast on kelp. As sunflower stars waned, sea urchin populations exploded, decimating kelp forests that were already weakened by a mass of warm water called “The Blob” that swept up the coast in 2014.

Kelp is the foundation of Monterey Bay’s ecosystem because it not only provides habitat for a diversity of species, said Hamilton, it also sequesters massive amounts of carbon and helps cycle nutrients from beaches to the deep sea. “Kelp are like trees, only better,” Gravem added, because “you can’t eat trees, but lots of stuff eats kelp.”

To this day, sunflower stars have not come back to Monterey and the kelp forests are still in trouble. According to Gravem, the vast majority of sunflower stars globally have died from this wasting disease, with the number of individuals killed in the billions.

“We think it might be the biggest marine species die-off ever,” Gravem said. “Essentially in the lower 48, they’re probably not coming back without our help.”

“What Monterey does have going for it is the otters,” Gravem added. Sea otters are another top predator of urchins, so because Monterey was able to bring back the otters, kelp forests are better situated here than in other regions along the coast. For sunflower stars to come back to Monterey Bay, the current research, management, conservation, and recovery efforts will have to succeed.

Blood stars were also hit by the wasting epidemic, but not as badly as other species. (Joe Gaydos — SeaDoc Society)

If you do see a sea star, whether healthy or diseased, you can help by logging your observation here, logging the sighting on iNaturalist, and/or emailing your observation to seastarwasting@googlegroups.com. Stay up-to-date on sea star wasting at seastarwasting.org. To watch a video on sea star wasting visit https://youtu.be/KrfcglOmBYw

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November 07, 2020 at 10:14PM
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Sea stars struggling to recover from wasting epidemic - Monterey Herald

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