Welcome to the State of California 


Date: 5/6/2008 

Number: 08-25 

Contact: Suanne Buggy or Lea Brooks  (916) 440-7259 


Dr. Mark Horton, director of the California Department of Public Health (CDPH), announced that the annual quarantine on sport-harvested mussels taken from the ocean waters of California for human consumption is effective from May 1 through Oct.  31.  This quarantine affects all species of mussels harvested by the public anywhere on the California coast, including all bays and estuaries.

This statewide mussel quarantine is intended to prevent human cases of paralytic shellfish poisoning (PSP) and domoic acid poisoning (DAP).  The overwhelming majority of human cases of PSP illnesses occur between spring and fall. To date, no cases of human poisoning from domoic acid poisoning are known to have occurred in California.

PSP affects the human central nervous system, producing a tingling around the mouth and fingertips within a few minutes to a few hours after eating toxic shellfish.  These symptoms typically are followed by disturbed balance, lack of muscular coordination, slurred speech and difficulty swallowing.  In severe poisonings, complete muscular paralysis and death from asphyxiation can occur.

Symptoms of DAP can occur within 30 minutes to 24 hours after eating toxic seafood.  In mild cases, symptoms may include vomiting, diarrhea, abdominal cramps, headache and dizziness.  These symptoms disappear completely within several days.  In severe cases, the victim may experience excessive bronchial secretions, difficulty breathing, confusion, disorientation, cardiovascular instability, seizures, permanent loss of short‑term memory, coma and death.

There is no known antidote to the toxins and cooking cannot be relied upon to destroy them.  Anyone experiencing symptoms of PSP or DAP should seek immediate medical care.

Consumers of sport-harvested, bivalve (two-shelled) clams or scallops are advised to eat only the white meat, removing and discarding the dark-colored organs or viscera before cooking.  Shellfish for human consumption should only be taken from areas free of sewage or chemical contamination during all times of the year.

No commercially harvested shellfish are included in the annual quarantine.  All commercial shellfish harvesters in California are certified by the state and subject to strict requirements to ensure that all oysters, clams and mussels entering the marketplace are free of toxins.  Commercial harvesting is stopped immediately if potentially dangerous levels of toxins are found.

CDPH’s shellfish sampling and testing program for PSP and DAP issues warnings or establishes special quarantines when needed.  Local health departments, various state and federal agencies and others participate in the monitoring program.

For updated information on quarantines and shellfish toxins, call the CDPH shellfish information line at (510) 412-4643 or toll-free at (800) 553-4133.

Last modified on: 6/5/2009 8:37 PM