Plagues,
Pestilences and Diseases
Deadly poisonous algae bloom killing Southern California
dolphins, sea lions
By Robert Jablon, The Associated Press | The Canadian Press – Tue,
19 Apr, 2011 7:30 PM EDT
LOS ANGELES, Calif. - Dolphins and sea lions that have died along
the Southern California coast in recent weeks may be victims of a
deadly neurotoxin produced by a seasonal algae bloom, experts said
Tuesday.
The same poison was found in samples from millions of fish that
suffocated in a Redondo Beach harbour last month, and researchers
hope to determine if it is present in samples from a similar but
smaller fish die-off Monday in Ventura Harbor.
Experts don't believe the fish died from the toxin but some marine
mammals have become its victims.
In the past few days, three sea lions and three dolphins that
beached themselves in Orange County died or were destroyed because
they had incurable domoic acid poisoning, said Kirsten Sedlick,
animal care supervisor for the Pacific Mammal Center in Laguna
Beach.
On Tuesday, the centre dispatched crews to rescue another four
dolphins and a sea lion, she said. Tests will determine whether
they also were victims of the neurotoxin.
Domoic acid is produced naturally, but levels often soar in the
spring with the blooming of a certain species of algae off the
California coast. At least one bloom was spotted in the past few
weeks off the Southern California coast.
Mussels and small fish eat the algae and concentrate the poison,
then are eaten in turn by pelicans and sea mammals.
Since April 3, the National Oceanic and Atmospheric Administration
has received reports of about 40 sea lions and 17 dolphins with
domoic acid poisoning symptoms.
The outbreak was still relatively mild but it was too early to
tell whether it might become more serious, said Joe Cordaro, an
NOAA wildlife biologist.
"You never know how bad they're going to be, and we still don't
know what the factors are that cause these major blooms," he said.
"We don't know if it's (storm) runoff, we don't know if its high
temperatures ... there's just so many factors."
In 2002 and 2003, domoic acid poisoning was blamed for sickening
or killing more than a thousand sea lions and 50 dolphins in
Southern California.
Humans aren't at risk unless they consume contaminated shellfish.
Because of elevated domoic acid levels, the California Department
of Public Health put its annual quarantine on sport harvesting of
wild mussels into effect on March 29 — a month earlier than usual.
Commercially harvested mussels are not affected, the agency said.
The agency warns that eating tainted mussels can cause severe
illness, coma and even death. The quarantine runs through Oct. 31.
The department declined to speculate on why the levels were high
so early.
Domoic acid also was found in sardines taken from Redondo Beach on
the Los Angeles County coast, where an estimated 2.5 million fish
crowded into King Harbor, depleted the oxygen and suffocated last
month.
What caused the fish to pack in to the harbour is unknown.