SONOMA COUNTY, Calif. (KRON) — At several Bay Area beaches, there’s been an uptick in dead sea lions in the last few weeks, including at Doran Beach in Sonoma County. This summer, a disease swept through and killed a large number of mammals in Southern California.

Marine experts say what’s happening here is different than the tragedy in Southern California, but nonetheless disheartening and comes with a warning.

“This particular disease, Leptospirosis, is spread through urine,” explained Sue Pemberton with the California Academy of Sciences.

A sea lion carcass was about a half mile from the main entrance to Doran Beach ranger station. It is one of nearly a dozen that have washed ashore in the last few weeks here.

“We want to hear from people,” explained Pemberton. She helps coordinate response teams who perform necropsies on dead sea life, including sea lions.

Although the teams have not been out to Doran Beach, they have responded to other washed-up carcasses in San Mateo County.

Pemberton advises keeping your distance if you see a dead sea lion on the shore. Leptospirosis can spread to other animals such as dogs.

At Doran Beach on Tuesday, Juan Hugo was walking along with a friend. He thought it would be a good idea if there were posters warning people to keep clear.

“Yeah, they should do that,” Hugo said.

The Marine Mammal Center in Sausalito has responded to several cases of lethargic sea lions. They are currently monitoring five sea lions that were sick.