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Deadly sea toxin kills California dolphins and seals
26th May 2003
Planet Ark
LOS ANGELES - A naturally occurring, but deadly, toxin produced by sea algae is killing record numbers of dolphins and sea lions along sections of California's southern coast, the state's wildlife agency said.
The animals are being poisoned by domoic acid, a nerve toxin produced by a certain species of microscopic algae, the California Department of Fish and Game said.
The exact cause is a mystery, but scientists speculate that the algae may be thriving on nutrients from agricultural runoff or sewage, said Chamois Anderson, a spokeswoman for the department. Weather patterns could also play a role.
Since April, five dolphins and 148 California sea lions have been found stranded on beaches from Santa Barbara County south through Orange County.
All of the dolphins died and many of the sea lions, most of them large adult pregnant females, are being treated at marine mammal rehabilitation centers. Pelicans have also been taken to shelters for care, the state agency said.
Marine animals and seabirds can be poisoned by eating small fish that have ingested the toxin. Filter-feeding animals like mussels and small fish like sardines feed on the toxin-laced algae.
Last year, according to the California wildlife agency, more than 1,000 marine mammals were found stranded or dead on state beaches. Hundreds of seabirds, including endangered brown pelicans, grebes and loons, were also affected by that outbreak.
Domoic acid can cause human illness or even death and the California Department of Health Services warns each year not to eat self-harvested mussels or shellfish between May 1 and Oct. 31.
The health agency also advises Californians to eat only the white meat of sport-harvested, bivalve clams or scallops and said elevated levels of domoic acid have been detected in mussels, oysters, sardines and anchovies from Santa Barbara, Ventura, Los Angeles and Orange Counties.
So far, there have been no reported cases of human poisoning from domoic acid in the state.
Officials said people should not try to help beached animals or birds, because domoic acid poisoning can provoke aggressive behavior and the animals are too sick to go back in the water.
Story by Deena Beasley
REUTERS NEWS SERVICE
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