The Center for Biological Diversity submitted a petition Thursday asking the U.S. Fish and Wildlife Service to reintroduce sea otters to a large stretch of the West Coast.

The Fish and Wildlife Service last year published an assessment finding that sea otter reintroduction to the Pacific Coast is biologically, socioeconomically and legally feasible.

Threatened southern sea otters occupy only 13% of their historic range, and a small population of the animals currently lives on California’s central coast, according to a news release.

“Bringing the sea otter back to the broader West Coast would be an unparalleled conservation success story,” said Kristin Carden, a senior scientist at the Center. “Not only would the sea otters thrive, but they would also help restore vital kelp forest and seagrass ecosystems.”

The petition under the Endangered Species Act cites the importance of range expansion to the recovery of sea otters. It recommends that reintroduction occur in the region between San Francisco Bay and Oregon. It also asks that the Fish and Wildlife Service conduct an assessment to determine the feasibility of reintroduction from southern California into Baja California, Mexico.

North America’s smallest marine mammal, sea otters rely on a dense layer of fur rather than blubber to keep warm. This thick, luxurious coat attracted commercial fur traders, who engaged in a wholesale slaughter of sea otters beginning in the mid-1700s.

Traders nearly drove the species to extinction, wiping out 99% of the global population. The species was thought to be extinct in California until a group of approximately 50 survivors was discovered near Monterey Bay in the early 20th century.

California’s southern sea otters have been listed as threatened under the Endangered Species Act since 1977, and the southwest Alaska population of northern sea otters has been listed since 2005.

Re-establishing sea otters along the Pacific Coast would allow these subspecies to intermingle, enhancing genetic diversity and helping them adapt to changing environmental conditions. A higher population would also make it more likely that the species would withstand an oil spill or other catastrophe.

Sea otters are threatened by oil spills and other contaminants, low genetic diversity, disease, shark bites, and climate change. Reintroductions have proven instrumental in helping reestablish sea otter populations in British Columbia, Alaska, Washington state, and Elkhorn Slough and San Nicolas Island, California. Expanded repopulation of the West Coast without active assistance is unlikely.