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Community Corner

As Dolphin Death Toll Rises, Marine Experts Look for Answers

Some suspect domoic acid, a biotoxin found in algae blooms off the California coast that was detected in sardines found dead in King Harbor in March.

In the past two days, five more common dolphins have washed up on Southern California beaches, dead or dying, bringing the total death toll to 16 dolphins and one Dall's porpoise since April 1.

"The dolphins that are washing up on the beaches are a window to what’s going on in the ocean's environment," said Joe Cordaro, a National Marine Fisheries wildlife biologist. "Undoubtedly more animals are dying at sea, it's just impossible to say how many."

Most have washed ashore from Malibu to Newport Beach, including recent strandings at Rat Beach, Hermosa Beach and Manhattan Beach.

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A sick dolphin came ashore at Manhattan Beach last weekend, said Peter Wallerstein from the Marine Animal Rescue Team.

"When I got there, there were at least 100 people that had surrounded the sick animal," he said. "Kids were screaming, people were pulling the dolphins flippers and others were poking at it while it was having seizures."

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Wallerstein said the public has to they encounter.

"All that commotion can be the thing that ultimately ends the dolphin's life," Wallerstein said.

That particular dolphin died a short time later. 

Unlike sea lions , most of the ailing dolphins have died. Tests indicate domoic acid was responsible in four of the dolphin deaths and is the suspected cause of death for the rest.

"We are highly suspicious that it was domoic acid poisoning," said Michele Hunter, director of operations and animal care for the Pacific Marine Mammal Center in Laguna Beach, referring to two dolphins that came ashore in Newport Beach during the weekend.

Domoic acid is a naturally occurring biotoxin found in algae blooms off the California coast. It is caused in part from fertilizers, industrial waste and other pollutants that wash out to sea. It remains dormant in fish and shellfish that feed on the plankton until larger mammals and birds feed on the fish that have ingested the substance.

The toxin was of some of the in King Harbor in March.

Domoic acid does not usually have a large impact on dolphins, Cordaro said. The last time a domoic acid event affected dolphins on a large scale was in 2005,  when about 50 dolphins felt the biotoxin's effects, he said.

Cordaro said there is no way to tell how much longer this will last. He points out there were five dolphin deaths last Wednesday, then nothing until Sunday when there were another five deaths.

“This thing has been stopping and starting from the beginning," he said. "There really is no way of telling how much longer it will last. It could be over and then again it could go on for another month."

Anyone who sees an injured marine animal should stay away from that animal and call Wallerstein at 800-39WHALE.

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