Threatened listing proposed for sunflower sea star after population devastated by wasting disease

A healthy sunflower sea star is seen on the seafloor in 2014. (Photo by Ed Gullekson/Washington Department of Fish and WIldlife, provided by NOAA Fisheries)

Alaska (Alaska Beacon) - The creature, with a range from Baja California to the Aleutians, would be the first sea star with an Endangered Species Act listing.

One of the world’s largest sea stars is on track to receive Endangered Species Act protections.

Federal regulators announced on Wednesday that they are proposing a threatened listing for the sunflower sea star, a creature that has been killed off in much of its Pacific habitat by disease. While the effect of a listing on Alaska and its fisheries is not certain, scientists say they don’t expect significant changes in the state in the near term.

The official proposal for the threatened listing is scheduled to be published Thursday by the National Oceanic and Atmospheric Administration’s Fisheries Service. That will kick off a 60-day public comment period, with a final listing decision due in a year.

The proximate cause of the sunflower sea star decline is Sea Star Wasting Syndrome, which wiped out about 90% of the animals across its vast range, according to NOAA Fisheries. The wasting system has hit a variety of sea star species, though sunflower sea stars have suffered especially severe harm, according to scientists. It causes legs to fall off and, ultimately, results in disintegration of the animals’ bodies. Climate change may be behind that disease, as the arrival of Pacific marine heat waves coincided with the disease outbreak, according to federal biologists.

Sunflower sea stars are distinctive and colorful creatures found from Baja California to Alaska’s Aleutian Islands. They can grow up to 24 legs and be as big as 3 feet in diameter. They are considered a keystone species in the marine environment; their top food is sea urchins, and by eating the kelp-feeding urchins, they protect kelp forests that support numerous other species, including those of commercial significance in Alaska.

If it goes through, the listing will be the first for any sea star under the Endangered Species Act.

The proposed listing is unusual in other ways.

While there are some big geographic differences in population trends, with the heaviest impacts in the southern areas and less-severe impacts in Alaska and other northern areas, the listing would cover sunflower sea stars over their entire range. That is because the Endangered Species Act does not allow listings of invertebrates to be broken down into distinct population segments, as is the case in Alaska with endangered western Steller sea lions and Cook Inlet beluga whales.

Compared to the near-total wipeouts “across the board” in Lower 48 waters, declines in Alaska waters range from 40% to 100%, said Sadie Wright, a Juneau-based protected species biologist with NOAA Fisheries who helped compile the status review that led to the proposed listing.

Beyond listing, ensuing recovery work could consider geographic differences, she said during an online news conference. “Later in the process, when we’re looking at protections, we can tailor those more regionally if that’s a better fit,” she said.

There is also no plan, as of now, for designation of critical habitat, normally a part of the regulatory action to conserve listed species, officials said. That is because critical habitat is considered “indeterminable,” said Dayv Lowry, the NOAA Fisheries biologist who led the status review.

“We know that it occurs around kelp forests. We know that it’s a part of that ecosystem and an integral part of it. But the animal is also found over rock piles, sand, mudflats, eelgrass meadows. It’s found all over the place,” Lowry said in the news conference. “At this point, we’re saying the animal is protected anywhere and everywhere you encounter it.”

There are additional unknowns. Scientists are still trying to figure out the sea stars’ life cycles and lifespans and fundamental biology, Lowry said. The exact pathogen that triggered wasting syndrome is not yet identified. And any contribution of the sunflower sea star deaths to a longer-term decline in kelp forests is still unclear.

“The biggest problem that we ran up in trying to do the status assessment is that there’s a lot of information about the species that is not well known,” he said.

Also yet to be determined are any potential impacts of listing to commercial fishing.

Whatever damage is being done to the sea star population by bycatch, the unintended catch during harvest of targeted fish, it is considered a low-level threat, far overshadowed by the wasting syndrome, Wright said.

“While we want to work with commercial fisheries and the fishery management councils to gather more information and promote safe handling of sea stars that are bycatch in fisheries, we don’t anticipate significant changes to fisheries as an outcome of this proposed rule,” she said.

There is an effort to get more details in bycatch reports, Lowry said. For now, those reports often refer to sea star bycatch generically, without identifying species.

While listing will not itself fight off any disease or address climate change, it can heighten awareness and help support various research activities, the NOAA officials said at Wednesday’s news conference. Among the programs they cited was the captive-breeding research underway at the University of Washington’s Friday Harbor Laboratories.

The proposed listing results from a petition submitted in 2021 by the Center for Biological Diversity.

In a statement, the center hailed Wednesday’s listing news.

“Protection under the Endangered Species Act will be so important for reviving these incredible sea stars,” Miyoko Sakashita, the center’s oceans program director, said in the statement. “Disease fueled by climate change has devastated this gorgeous species, and these safeguards will help tackle threats to their survival and promote the health of the kelp forests they live in.”

Officials with Alaska Department of Fish and Game and Alaska fishing organizations have previously expressed concerns about the wide geographic span that listing would affect.