15 to 20 Sea Lions Rescued as Domoic Acid Illness Spikes in Monterey Bay

The Marine Mammal Center rescued 15 to 20 sick California sea lions in three days as reports of animals with neurological symptoms increased around the Monterey Peninsula. The center said the cluster was consistent with another flare up of domoic acid poisoning along the California coast.

KSBW reported the new rescue count on August 29 after visiting the center's triage station in Castroville. Four sea lions were receiving care there at the time. Three dead sea lions had also been found at Moss Landing State Beach.

The rescue count rose in three days

The animals arriving in care were primarily large subadult and adult California sea lions, according to staff interviewed by KSBW. Rescue teams expected more animals to arrive as calls continued from beaches around Monterey Bay.

The Castroville site allows staff to assess and stabilize sea lions before deciding whether they need continued treatment at the center's hospital in Sausalito. The 15 to 20 figure covers three days and is not a final total for the event.

Why domoic acid is suspected

Domoic acid is a naturally occurring toxin produced during some harmful algal blooms. Small fish can accumulate the toxin, and sea lions may receive a much larger dose when they eat those fish, The Marine Mammal Center explains.

Affected sea lions may appear disoriented, move without coordination or experience seizures. Severe poisoning can be fatal without treatment. The center's patient records show recent admissions from the Monterey area with confirmed domoic acid toxicosis, but public reporting did not confirm the diagnosis for every animal in this new group.

Center staff also said they did not yet have a definitive explanation for why the number of sick animals rose so sharply over these three days. The current evidence supports a suspected domoic acid event, not a conclusion about the precise conditions that produced the spike.

What beach visitors should do

A sick sea lion can behave unpredictably and should not be approached. The Marine Mammal Center advises people to remain at least 150 feet away, keep dogs and children back and avoid disturbing the animal.

People who see a stranded or distressed marine mammal in the center's response area can call 415 to 289 SEAL (7325). A report should include the location and a description from a safe distance. Trained responders can then determine whether the animal needs monitoring or rescue.

What remains unknown

The public reports available on August 29 did not provide individual diagnoses or outcomes for all rescued animals. They also did not connect the three dead sea lions at Moss Landing to a confirmed cause of death.

Buddylio will update this report if The Marine Mammal Center or another responsible agency releases a material change in the rescue total, diagnoses or outcomes. Readers can find more verified conservation and animal rescue developments in Buddylio's Wildlife coverage.

How we reported this: Buddylio reviewed the named sources, checked the organizations and figures shown above, and added context for animal lovers. Any illustration is labeled and does not depict the actual animals or scene. This report was checked on August 29, 2026. The rescue response was active, and domoic acid poisoning had not been reported as confirmed for every animal in the group. Articles are editorial content, not veterinary advice.