Investigators say water pollution is contributing to a spate of marine mammal deaths that have scattered carcasses along the California coast.
In the last several weeks, dozens of whales, dolphins and sea lions have washed ashore dead or dying from Venice to San Luis Obispo. The latest discovery occurred Tuesday in Ventura, where an 8-foot juvenile minke whale washed up dead near the end of San Pedro Street at San Buenaventura State Beach. Lifeguards buried it in the sand.
"It is episodic. Springtime is peak time when this happens," said Michelle Berman, assistant curator and marine mammal specialist for the Santa Barbara Museum of Natural History. "Animals are reproducing and we have upwelling and nutrients that can lead to red tides. But to have so many in a short time frame is not so common."
In Santa Barbara, a 29-foot sperm whale washed ashore April 9 near Isla Vista. In both instances involving whales, investigators collected tissue samples from the carcasses in an effort to pinpoint the cause of death.
Meanwhile, numerous dolphins and sea lions are washing ashore sick or dead on Southland beaches.
Peter Wallerstein, president and founder of the Whale Rescue Team in Playa del Rey, said he has conducted 78 marine mammal rescues this year, many of them common dolphins. He rescued a dolphin at Santa Monica State Beach and another at Venice Beach this week. A live harbor porpoise washed up near Oceano Dunes in the San Luis Obispo area, but died later.
Joe Cordaro, a wildlife biologist with the National Marine Fisheries Service, said he does not see an ecological disaster underway, but he is concerned about toxic algae. It can produce domoic acid, which accumulates in shellfish and fish and sickens seabirds, otters, sea lions, dolphins, whales and humans that eat the shellfish and fish. He said some sea lions show symptoms of domoic acid poisoning, including seizures and paralysis, but he said investigations are underway to determine if other factors are contributing to the problem.
"We get spurts like this from time to time," Cordaro said, "but whenever we get one like this, this many [fatalities] at one time, it raises our antennae."
Cordaro said the last major incident involving stranded dolphins and marine mammals occurred between 2002 and 2003.
Turbulent spring weather, including wind and surf, churns the ocean and contributes to upwelling of nutrients from the deep sea, which contributes to algal blooms and animal poisonings, Berman said.
Officials warn beachgoers to keep themselves and children a safe distance from animals that appear distressed, especially sea lions. Also, it is against federal law to harass the animals.
Officials say that as long as environmental conditions continue to pump nutrients through the water, toxic algae is likely to flourish and more marine mammal injuries and deaths can be expected.