SAN FRANCISCO— The Center for Biological Diversity sued the Trump administration today over the National Marine Fisheries Service’s failure to protect imperiled sunflower sea stars as threatened under the Endangered Species Act.

The Service proposed to protect the sea stars in 2023, in response to a petition by the Center. The agency was required to finalize the listing in a year, but did not meet that deadline. The second Trump administration has not yet listed a single species under the Endangered Species Act.

“These incredible many-armed sea stars have taken a huge hit from climate change and obviously need protection, but for years federal officials haven’t acted,” said Miyoko Sakashita, oceans program director at the Center. “It’s been painful to watch disease spread among the species as the ocean warms. We need to jump in and do everything we can to save these gorgeous sea stars. The Trump administration has a clear legal duty to take action on these amazing animals.”

Today’s lawsuit was filed in the Northern District of California.

Since 2013, 90% of the Pacific population of these sea stars has been lost to the gruesome and disfiguring sea star wasting disease. The disease outbreak is driven by climate change, with warmer oceans making the effects more severe and deadly. NOAA has declared an El Niño event from June through February 2027, during which above-average warm water is pushed up from the equatorial Pacific. Ocean acidification is also a threat.

Sunflower sea stars — who have up to 24 arms, can be a meter wide, and come in a variety of bright colors — live along shorelines from Southern California to southern Alaska. They’re voracious predators whose consumption of sea urchins helps prevent the overgrazing of kelp forests, maintaining coastal ecosystems.

The sea star wasting disease outbreak is considered one of the largest marine epidemics, causing massive sea star mortality along the West Coast. The disease is a gruesome killer, causing lesions, contortions, lost limbs, disintegration and death. Sunflower sea stars have never recovered from being nearly wiped out by the disease and are now classified as critically endangered by the International Union for Conservation of Nature.

A listing will help reduce threats to the sea star’s habitat from water pollution, dredging, shoreline armoring and other coastal development projects that might push the species toward extinction. It will also provide the species with a recovery plan.