SAN FRANCISCO, CA —California sea lion died at San Francisco's Crissy Field on Monday after showing signs of domoic acid poisoning, according to The Marine Mammal Center in Sausalito.
Callers first reported the large sea lion on the beach showing signs of distress, including head weaving and seizures, about 8 a.m.
A trained responder from the marine mammal center was dispatched to assess the animal and manage the scene at Crissy Field, a public waterfront area east of the Golden Gate Bridge.
While the center was organizing a rescue team, however, the sea lion unfortunately died on the beach, a center spokesperson said.
Samples were taken to determine if the animal was suffering from domoic acid poisoning, but the results won't be available on Monday, according to the center.
The Marine Mammal Center has seen a flare-up of sea lions stranding with signs of domoic acid poisonings this year, primarily California sea lions.
Domoic acid is produced during certain harmful algal bloom events. The neurotoxin accumulates in small fish, like sardines and anchovies, which are then eaten by marine mammals like sea lions in large quantities.
Since Aug. 24, about 40 sea lions have been rescued in Monterey County and southern Santa Cruz County, with additional rescues in San Mateo, San Francisco, Marin and Sonoma counties. A handful of northern fur seals have also been affected.
The center said it has already passed its average annual number of domoic acid rescues -- normally about 75-90 animals per year across a 600-mile California response range.
"As we are currently seeing intense surges of domoic acid along the California coast, our hotline is inundated with reports of animals in need to the tune of 3-6x our normal call volume, with some days seeing nearly 700 calls," the center said in a statement.
In sea lions, the brain is attacked by domoic acid, causing seizures and heart failure. When it's untreated, it usually causes permanent brain damage, according to the marine mammal center.
The toxin will naturally flush from an animal's system over time, but sea lions repeatedly exposed to the toxin will suffer longer-lasting and more serious effects.
Domoic acid also affects humans who eat contaminated crab, shellfish and fish, causing a life-threatening condition known as amnesiac shellfish poisoning, the marine mammal center said.
People and their pets should keep their distance from stranded or distressed marine mammals and call the center's hotline, if they are located between Mendocino and San Luis Obispo County, at 415-289-SEAL (7325).
More information is available at marinemammalcenter.org/ .
By Kathleen Kirkwood
Bay City News
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