Dolphins’ Deaths Linked to Algae

Scientists have discovered toxic algae blooms off Catalina Island, confirming suspicions that a neurotoxin that induces crazy behavior in animals and inspired Alfred Hitchcock’s movie “The Birds” is linked to the recent deaths of dolphins and sea lions.

A federal lab also detected high levels of telltale domoic acid in urine samples in two of the 31 dead dolphins that have washed ashore on Southern California beaches in the last two months. Biologists are waiting for an analysis of brain tissue to be certain of the link.

“We have a little bit of a smoking gun,” said John Heyning, a marine biologist leading the investigation. “The tests prove they were exposed to domoic acid. It doesn’t prove they were killed by it.”

Meanwhile, a volunteer group attempted to rescue a confused dolphin--thought to be suffering from the same poisoning--from a canal of seawater used to cool an Oxnard power plant.

The volunteers were hoping to snag the animal in a net, hoist it onto a flatbed truck and whisk it to a marine mammal rehabilitation and testing center in Laguna Beach. The group will try again today.

Sam Dover, a veterinarian on the scene, said that although he will not know until the animal is tested, he suspects the dolphin has lost control of its neurological functions, including its usually keen sense of navigation.

Water samples collected in at least two places off Catalina have identified invisible blooms of a single-cell plankton, in the genus Pseudonitzschia, which produces the potent toxin that attacks the brain and nervous system.

Such blooms have been well documented in cooler waters off the coast of Canada and Washington and in Monterey Bay. Scientists don’t know what causes them.

A recent bloom in Monterey Bay prompted the California Department of Health Services to issue an advisory against eating mussels, clams and scallops, as well as anchovies, sardines and crabs caught there.

Domoic acid is concentrated in these filter-feeding animals. Although three human deaths have been recorded in Canada, domoic acid poisoning is almost exclusively a problem for dolphins, sea lions and seabirds that feed on sardines and anchovies that consume the algae.

Public health officials, animal rescue workers and wildlife biologists have been scrambling since the body count began rising over the last five weeks from dolphins and sea lions washed ashore on beaches in Ventura, Los Angeles and Orange counties.

Los Angeles County health officials have stepped up testing of near-shore waters to make sure the algae blooms pose no public health hazard. So far, the tests have been negative.

Anthony F. Michaels, director of USC’s Wrigley Institute for Environmental Studies, found a bloom on his way to Catalina. He stopped to take water samples when he saw a seal lion behaving “extremely erratically.” Initial lab results confirmed the presence of Pseudonitzschia.

The Catalina Island Marine Institute has also turned up positive tests, said Gregg Langlois, a marine biologist with the state Department of Health Services.

“There could be a bunch of localized blooms,” said Heyning, the investigator who works at the National History Museum of Los Angeles. “We really don’t know for sure.”

Heyning said that as far as he can tell, all of the affected dolphins have been male. It is just one of many mysteries surrounding the recent rash of deaths.

Dolphins cannot live long once they beach themselves, and virtually all of them were found after they had died.

Some of the sea lions, which commonly haul themselves out of the water to rest, have survived. Four sea lions with suspected domoic acid poisoning are being nursed back to health at the Fort MacArthur Marine Mammal Care Center in San Pedro.

“Some exhibit seizures and they look very disoriented,” said Jackie Jaakola, the center’s director. “Their eyes are pointed in different directions.”

As upsetting as the deaths of these seemingly smiling or puppy-eyed creatures can be, wildlife biologists stress that the naturally occurring poisoning holds no serious threat to the otherwise healthy species.

An estimated 200,000 California sea lions feed and frolic in state waters. Federal officials estimate that 330,000 common dolphins thrive off the West Coast.

The common dolphins, with their distinct two-toned gray and white markings, generally remain far offshore.

They are most often spotted while escorting boats on the passage to Catalina or other Channel Islands.

“There are plenty of animals out there and we don’t want the public in shock that all of the dolphins are dying off,” said Joe Cordaro, a wildlife biologist with the National Marine Fisheries Service.

“The populations of dolphins and sea lions are doing very well.”

Wildlife officials have yet to receive reports of dead or erratic behavior of seabirds, as happened during one of the largest outbreaks of domoic acid poisoning in 1991.

At that time, wildlife officials saw large-scale deaths of pelicans and cormorants in the Monterey Bay.

Domoic acid poisoning is thought to be the inspiration for Hitchcock’s horror movie “The Birds.”

In the real life event that captured the late director’s imagination, hundreds of gulls and shearwaters went berserk one summer morning in 1961, attacking the seaside town of Capitola, near Santa Cruz.

Disoriented and crazed, they dove into street lamps, crashed through windows and nipped a few people.

The incident fascinated Hitchcock, who was vacationing nearby. He included newspaper clippings about the Capitola attack in his studio proposal for the movie that appeared two years later.