Algae blooms sickening sea lions along California coast, experts say

SAN DIEGO (FOX 5/KUSI) — Concerns are rising over the health of California’s sea lion population, with toxic algae blooms potentially responsible for dozens of sick sea lions along the coast, including some in San Diego County.

Experts say the toxin — known as domoic acid — is not only harmful to sea lions, but also a risk to humans who consume tainted shellfish.

Domoic acid attacks the brain and can lead to serious illness.

Marine mammal experts like Dr. Clarissa Anderson from the Scripps Institution of Oceanography are raising a red flag about the dangers of domoic acid, a neurotoxin produced by naturally occurring algae in the water.

Dr. Anderson says the toxin is found in plankton, which is consumed by fish like anchovies—a major food source for sea lions. When sea lions ingest this toxin, it can make them extremely sick and even be deadly.

“Bobbing and weaving of the head, seizures, erratic swimming, erratic behavior. When they are on the beach they are often lethargic, maybe even foaming at the mouth are signs of domoic acid poisoning,” Dr. Anderson said. “These sea lions may even seem slightly friendly at times, which is counterintuitive.”

Over the past two weeks, numerous cases of domoic acid poisoning have been reported, particularly along the Central Coast. At least three suspected cases have been identified in San Diego County.

“We are seeing quite a few cases in Los Angeles County, Orange County, and also San Diego at SeaWorld because they are the first responders here,” Dr. Anderson said. “It’s tapering off as you head further south, which could mean we’re having a smaller bloom in Southern California, or that these animals are acquiring the toxin further north and then swimming into Southern California.”

Since June, nine seal pups were born at La Jolla Cove; at least three died. However, the cause of their deaths remains unknown.

Carol Toye of the Sierra Club Seal Society highlighted the importance of necropsies to determine the cause of death. “A necropsy is where veterinarians will analyze the tissues and analyze the cause of death. None of that was done, unfortunately.”

Toye, whose organization educates the public about sea lions, also urged people to keep their distance from these marine mammals. “If you do see a sea lion that is crawling out in an area which is unusual, or is acting strange, stay at least 50 feet away,” she advised.

Experts said it’s rare for humans to get sick from domoic acid because it requires ingestion.
Swimming in the ocean, they note, does not pose a risk for this type of poisoning. They also said the algae blooms occur in warmer ocean temperatures.

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