Public health officials are warning people to avoid eating sport-harvested shellfish, anchovies, sardines and crabs taken from the coastal waters of San Luis Obispo County.
The health advisory comes after testing showed high levels of domoic acid in shellfish taken from the county's coastal waters. Domoic acid is a toxin produced by algae in the water.
Symptoms of mild cases of domoic acid poisoning resemble flu symptoms including vomiting and stomach cramps. Severe cases of poisoning can result in seizures, coma and death.
Shellfish accumulate the poison in their tissues after filtering the algae out of the water. The poison can also accumulate in the viscera of anchovies, sardines and crab, commonly referred to as crab butter.
There is no known antidote to domoic acid poisoning. Anyone experiencing poisoning symptoms should seek immediate medical attention.