Sea Lions Join Ocean’s Sick List

California sea lions are the latest marine mammals to wash ashore on Southland beaches. Since Sunday, five pregnant sea lions have been found disoriented and having seizures on beaches in Los Angeles and Ventura counties.

The two that survived were being cared for Tuesday at the Fort MacArthur Marine Mammal Care Center in San Pedro. The lethargic, 200-pound marine mammals were lying in their pens, disoriented and too weak to eat. They’re being force-fed ground-up fish as well as medicine, vitamins and electrolytes.

Center officials believe a naturally occurring neurotoxin that is blooming off the coast between Monterey and San Luis Obispo is responsible for the sickness. The scientists suspect the sea lions ate fish that contained the toxin in that area but became ill in Southern California waters. Domoic acid is found in a single-cell, plant-like organism. Low levels are always present, but blooms can create toxic levels. The microscopic organisms are eaten by the sardines, anchovies and other small fish that sea lions feast on, said center director Jackie Jaakola.

Of the 34 sea lions that have washed ashore in Los Angeles and Ventura counties this year, officials suspect half suffered from domoic acid poisoning. Typically, such cases are seen in late summer or early fall, and experts aren’t sure why there have been so many in the winter and spring.

“Something is going on out there,” Jaakola said, gesturing toward the Pacific Ocean.The sea lion sickness is giving new weight to the theory that domoic acid may have caused the deaths of 23 dolphins found on Southern California beaches in recent weeks.

“They seem to be having the same symptoms, they’re from the same body of water and there’s some overlap in their food,” said John Heyning, deputy director for research at the Natural History Museum of Los Angeles County.

Domoic acid was recognized as a health hazard in 1987, when 150 people became ill and four died from eating contaminated blue mussels on Prince Edward Island, Canada. It was blamed in the deaths of 100 brown pelicans and cormorants in Monterey Bay in 1991, and 50 sea lions between San Luis Obispo and Santa Cruz in 1998.

Some scientists believe bird attacks near Santa Cruz in 1961--upon which Alfred Hitchcock’s horror movie “The Birds” is based--were caused by birds eating fish that contained high levels of domoic acid.

“We’ve never recorded it in dolphins before,” Heyning said. “With sea lions getting it, it makes [the theory] even stronger because we have documented its effects on sea lions.”

Results from tests of dolphin tissue and brain at government laboratories in South Carolina and Washington, D.C., should be available by the end of the week, he said. If the link is proved, scientists will test archived tissue samples from an unexplained dolphin die-off in 1994.

Jaakola said the center has sent sea lion samples to federal labs but hasn’t received results. She said her experience with similar cases leads her to conclude that the sea lions were poisoned by domoic acid.

If the sick animals survive the first 48 hours, chances are good they’ll recover and be released within a few months to give birth in the wild. But federal officials say the sea lions have only about a 50% chance of making it through that crucial early period.

Jaakola advises beachgoers who see a stranded sea lion to call a local animal control agency. Beachgoers should not approach or touch the animal because it might lash out. “These are very disoriented, aggressive, pregnant females,” she said. “You don’t want to be around them.”