Sunflower sea stars, hit by a “climate-fueled pandemic,” play a key role in keeping marine ecosystems balanced.
Sunflower sea stars, huge starfish that until recently thrived in waters up and down the west coast of North America, are threatened with extinction and should be protected under the Endangered Species Act, federal officials said Wednesday.
The starfish have been devastated by a wasting syndrome that has been linked to the effects of climate change. It killed more than 90 percent of sunflower sea stars from 2013 to 2017, in what officials described as the largest marine wildlife disease outbreak on record. The sickness starts with lethargy and lesions followed by tissue decay. Starfish’s limbs drop off and they die within days, leaving a gooey pile.
“We think it’s likely exacerbated by the increasing ocean temperature,” said Sadie Wright, a protected species biologist with National Oceanic and Atmospheric Administration Fisheries who worked on the status review for the sunflower sea star. Rapid changes in temperatures, another consequence of climate change, also play a role.
The starfish’s collapse appears to be a factor behind a domino effect of ecological destruction in California’s kelp forests. Sunflower sea stars gorge on sea urchins, which have skyrocketed in abundance since the starfish disappeared. The vast numbers of sea urchins started overgrazing kelp, scientists believe, contributing to die-offs of kelp forests.
“When you remove the sea stars, you see the cascading effects,” Ms. Wright said.
Sunflower sea stars can sport some 24 limbs and span more than three feet, about a meter, from tip to tip. They have been documented from Baja California to the Aleutian Islands. While scientists estimate that 600 million individuals remain worldwide, that number represents less than 10 percent of the abundance before 2013. Scientists now struggle to find them south of Washington, Ms. Wright said.
The species is already considered critically endangered by the International Union for Conservation of Nature’s Red List of Threatened Species.
Some 20 other species of sea stars have also been hit by the wasting syndrome, though sunflower sea stars are thought to be among the worst affected.
The proposal to list sunflower sea stars as threatened follows a 2021 petition by the Center for Biological Diversity, a nonprofit advocacy group.
“I’m ecstatic that the sunflower sea star will get the safeguards of the Endangered Species Act,” said Miyoko Sakashita, the center’s oceans program director. “A climate-fueled pandemic nearly wiped them out, and I’m optimistic that a threatened listing will assist their recovery.”
One way that could happen is by making new funding available to research the mysterious pathogen that scientists believe is behind the wasting syndrome. A listing decision could also lead to more protections from water pollution, dredging and other coastal construction projects.
“The federal government will also have to develop a recovery plan for the sea stars,” Ms. Sakashita said, “which can mean more focus on disease prevention and even climate change.”
A final determination will be made in the next year. If listed, the sunflower sea star would be the first sea star to be federally protected.
“A lot of people are familiar with this species, it’s something they’ve seen when they were exploring tide pools as kids,” Ms. Wright said. “So there’s going to be a lot of surprise that this species we once thought of as common is now being considered for listing under the Endangered Species Act.”