Disease-decimated sunflower sea star could be listed as threatened species
May 17, 2023
One of the world’s largest sea stars is on track to receive Endangered Species Act protections.
Federal regulators 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 public comment period has ended on the proposal for the threatened listing published by the National Oceanic and Atmospheric Administration’s Fisheries Service. 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.
There is 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 a 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.
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 the harvest of targeted fish, it’s 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.
The proposed listing results from a petition submitted in 2021 by the Center for Biological Diversity.
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