A key starfish is now under threat of extinction, the government says

The illness, called sea star wasting syndrome, killed more than 90% of sunflower sea stars between 2013 to 2017, in what the National Marine Fisheries Service called the "largest marine wildlife disease outbreak on record."

If the proposal is finalized, the species will be the first sea star listed under the Endangered Species Act, the agency said.

The disease also has decimated more than a dozen other starfish species along the U.S. Pacific Coast.

After years of study, scientists still cannot agree on why so many starfish have succumbed to the wasting syndrome — whether the disease is caused by a pathogen, a change in the environment or a combination of the two.

This month, the Oregon Coast Aquarium announced it had developed a treatment for the disease.

But what is clear is that the sunflower sea star's big, puffy body is particularly vulnerable to the syndrome. The International Union for Conservation of Nature, which tracks imperiled plants and animals across the globe, has listed the sunflower sea star as critically endangered. Outbreaks may recur as the waters warm because of climate change, federal wildlife managers warned.

The loss of so many of the many-limbed predators has allowed sea urchins to devour kelp forests that shelter other marine species and sequester carbon out of the atmosphere. Off the coast of Northern California, kelp cover has declined by more than 95%, according to a recent study.

"I can only hope that the listing will bring additional public attention, not only to the plight of this charismatic species, but to its importance in helping to maintain healthy ocean ecosystems," said Jason Hodin, a University of Washington biologist whose lab has developed a captive breeding program for sunflower stars.

The goal of the breeding program, Hodin said, is to someday restore the starfish's population.

While it is difficult to stop the spread of a wildlife disease, the federal proposal will open up new funding opportunities to study the starfish, according to Dayv Lowry, a federal fisheries biologist.

That money, Lowry told reporters Wednesday, "wouldn't otherwise necessarily be there at the federal level."