ALERT: California Coast Mussels May Be Toxic — Do NOT Eat If Harvested Recreationally

Residents are advised of a California Department of Public Health or CDPH mussel quarantine order effective May 1 through Oct. 31, 2025. During the quarantine, all species of mussels gathered by recreational sport harvesters from California’s ocean shore should not be consumed by humans. The quarantine area extends from the Oregon border to the Mexican border, including all bays, inlets, and harbors in Los Angeles County. The Los Angeles County Department of Public Health continues to work with CDPH and collect shellfish for testing.

This quarantine is to protect and preserve public health under the California Health and Safety Code Section 131056. During the quarantine season, mussels may concentrate naturally occurring toxins that are highly poisonous to humans including paralytic shellfish poison or PSP and domoic acid biotoxins in bivalve shellfish (mussels, clams, oysters, and scallops). Cooking does not destroy the toxins.

This advisory does not apply to commercial shellfish from approved sources.

State law prohibits the sale or offering for sale for human consumption of any bivalve (two-shelled) shellfish, except by a State-certified commercial shellfish harvester or dealer. Shellfish sold by certified harvesters or dealers are subject to frequent mandatory testing and are not subject to this quarantine.

Mussels may be used or sold for use as bait when displayed and sold in containers labeled in boldfaced type letters at least one-half inch in height as follows: MUSSELS FOR BAIT ONLY, UNFIT FOR HUMAN FOOD.

Symptoms

Early symptoms of paralytic shellfish poison or PSP include tingling of the lips and tongue, which may begin within minutes to a few hours after eating toxic shellfish. These symptoms are typically followed by a loss of balance, lack of muscular coordination, slurred speech, and difficulty swallowing. In severe poisonings, complete muscular paralysis and death from asphyxiation can occur.

Clams and Scallops

People consuming clams or scallops are warned to remove and discard the digestive organs or viscera and any other dark parts. Only the white meat of clams and scallops should be prepared for human consumption. Also, bivalve shellfish should not be collected for food from any area subject to sewage or chemical contamination.  

If you or a family member experiences gastrointestinal or neurological symptoms after eating mussels taken for human consumption by recreational sport harvesters from California’s ocean shore, please submit a Foodborne Illness Report and seek medical care. 

Details: For additional information call the Shellfish Hotline at 1-800-553-4133 or online at the CDPH Marine Biotoxin Quarantines and Health Advisories.