If Alfred Hitchcock’s nature walk had taken a different turn in 1961 he might have brought sea lions to the big screen two years later.

The horror flick he did release that year is based on an incident that took place in the small central Californian town of Capitola near Santa Cruz. Way back in 1961, the oceanside town experienced what seemed, at the time, an attack by a flock of flighty sea birds. The birds were seen bombarding cars, people and shop windows, as well as pecking passers-by and staggering about spitting up portions of last night’s dinner. Hitchcock, who frequented the town, recalled this course of events and used it as a basis for his well-known horror film, The Birds.

But this erratic behavior was not just an episode of birds gone wild. Rather, it was the result of the birds’ consumption of shellfish tainted with domoic acid, a poison that has assailed the sea mammals of California for the past several years.

In what has become an annual occurrence, sea animals, primarily California sea lions and common dolphins, are washing up on beaches along the coast of California and dying from the accumulation of domoic acid in their systems.

Several agencies have been studying this annual domoic acid outbreak for years in attempts to understand the problem in more detail and to ultimately prevent the outbreaks before they occur. The National Oceanic and Atmospheric Administration’s National Marine Fisheries Service in Long Beach, Calif. is one such agency working with the hundreds of unhealthy mammals that wash up on the beaches annually. Joe Cordaro, a wildlife biologist with the agency, is currently overseeing the rescue of the dying animals. He has been involved with the domoic acid issue primarily during the last two years and is aware that the problem is annual, usually taking affect around March and lasting until June. This year it began in mid-April.

Search and Rescue

Domoic acid was first identified as the cause of the strandings five years ago.

“I’ve been recording numbers since 1998, and it seems to be happening on a yearly basis,” Cordaro said. “Last year over 1,000 animals came in, and we’re already starting to get a lot of animals.”

Cordaro and the agency work with the animals found along the coast from Ventura through Los Angeles counties. Their focus is to tend to the sick sea lions and dolphins that come ashore, and send them to the Fort MacArthur Marine Mammal Care Center in San Pedro after an initial monitoring period.

“We do a 48-hour watch and observation period on the beach,” Cordaro said, “and then we transport them to the San Pedro center for care and, hopefully, revival.”

However, such “revival” of the affected animals has been highly uncommon among the droves that are found on the beaches. Cordaro said it is difficult to keep these animals alive, and even more difficult to nurse them back to total health.

“The animals are transported to rehab centers if possible, but most of them die even before they get there,” Cordaro said. “Only a few survived last year through transport; none have made it yet this year.”

The majority of the sea lions rescued from the beaches are adult females in their prime reproductive years, close to giving birth. When possible, the pups are delivered prematurely before the mothers die. At least two pups have survived so far, Cordaro said. One possible reason for the large number of pregnant sea lions coming in is that during pregnancy the mothers have to eat more to sustain themselves along with their unborn pups – and by eating more, they also take more domoic acid into their systems.

Dolphins are even less likely to survive the domoic acid outbreak because they, unlike sea otters, need to stay moist to stay alive. Dolphins die within hours of being stranded.

The Marine Mammal Center of Santa Barbara is also involved in taking care of those affected by the domoic acid outbreaks. They have had similar difficulties in keeping affected animals alive.

“We had one live dolphin that came in,” said Peter Howorth, director of the Marine Mammal Center of Santa Barbara. “We had to put it down.”


Domoic acid is produced by a neurotoxic phytoplankton by the name of Pseudo-nitzschia australis, which occurs naturally in California’s waters. When there is a significant algal bloom, which has happened every spring for the last several years, an abundant amount of the poisonous domoic acid is produced. The toxin then amasses within the bodies of the sardines and anchovies that feed on the poisonous phytoplankton. The acid accumulates as it climbs the food chain into progressively larger animals like the sea lions and dolphins.

As the toxin is absorbed into the body, it affects the neural pathways of sea mammals and inhibits the neurochemical processes of those it afflicts.

In other words, they go crazy.

Common effects of domoic acid seen in animals washed ashore include head weaving and seizures, which may lead to permanent brain damage and eventual death if not treated.

Once these animals are brought in they may receive a number of treatments, including medications to control seizures, medications to reduce brain swelling, and possibly antibiotics for secondary problems resulting from the seizures, said Jackie Jaakola, director of the Fort MacArthur Marine Mammal Care Center. Biologists look for any possible way to help.

“For the treatment of cases that are viable,” Jaakola said, “we can give the animals lots of fluids to flush the toxin from their systems.”

The most recent population counts have approximated 300,000 common dolphins in the waters off of California. An estimated 200,000 sea lions, which were listed as a threatened species, dwell in the area. In 2002, 685 California sea lion deaths were documented, as were the deaths of 75 dolphins. Though these numbers are considerably high, the domoic acid deaths aren’t considered a threat to the overall populations of California sea otters and common dolphins.

“Last year there wasn’t much impact on the populations,” Cordaro said. “This year there probably won’t be much either.”

Officials warn that anyone finding a beached animal should not try to help it, but rather call the Marine Mammal Center’s hotline at 687-3255.