SANTA CRUZ — Volunteers with the Marine Mammal Center rescued a sea lion that washed up on the beach at Natural Bridges State Beach Sunday afternoon.
The Marine Mammal Center is a nonprofit organization and marine mammal hospital that rescues, rehabilitates and studies marine mammals in Hawai’i and along the California coastline. The organization received reports on its hotline of a California sea lion on the busy beach Sunday and a team of trained volunteers from the hospital’s triage facility in Castroville arrived at the beach just after 3 p.m.
The sea lion weighed about 200 pounds and appeared to be in poor condition, said Giancarlo Rulli, a spokesperson for the Marine Mammal Center in Sausalito. It was reactive and registered the volunteers’ presence but was lethargic. The volunteers worked together to corral the animal into a large metal box as a crowd of beachgoers formed to watch the rescue in progress. The crowd applauded once the sea lion was safely secured in the box and the volunteers carried it up the beach.
The sea lion was taken to the Castroville triage center, where it stayed overnight. Monday morning, the animal was found dead. It will be transported to the Marine Mammal Center’s main hospital in Sausalito. There, it will undergo an animal autopsy to try and determine the cause of the sea lion’s poor condition, strange behavior and its eventual death.
The rescue comes in the middle of a severe outbreak of leptospirosis, a bacterial infection that causes kidney failure in sea lions. The behavior of the sea lion at Natural Bridges was consistent with some leptospirosis symptoms, but the Marine Mammal Center cannot yet confirm whether the animal was infected.
This year’s leptospirosis outbreak has been the largest on record, Rulli said. The Marine Mammal Center has responded to over 450 California sea lions with the disease since July 1. For comparison, previous record years 2004 and 2018 each saw around 300 sick sea lions. The numbers seem to be tapering off now, Rulli said, but the epidemic isn’t over yet.
This year’s major outbreak is a mystery, according to Rulli. Scientists have been trying to understand why the disease spreads rapidly once every three to five years, and haven’t been able to find many answers. The current outbreak is particularly unusual, due to the large number of sick animals and the fact that outbreaks usually begin in the fall.
Leptospirosis can be fatal to dogs. For that reason, Rulli said, it’s important for owners to keep their dogs leashed on the beach and not allow them to approach sea lions or other marine mammals. Beach visitors are also advised to keep at least 150 feet of distance from marine mammals on the beach. Anyone who sees a marine mammal that could be sick or injured can call the Marine Mammal Center’s hotline at 415-289-7325, and volunteers will respond to evaluate whether the animal needs rescue.
Right now, it’s too early to tell if this bout of disease is an anomaly or a long-term problem for California sea lion populations, Rulli said.
“California sea lions are a conservation success story,” Rulli said. “Yet they are a species that is a sentinel for ocean health. So when they’re washing ashore sick, it’s really important that we pay attention.”