Susan Buckley, RN, Director, Public Health
Ira Singh, MPH, Deputy Director
Donald I. Baird, MD, Health Officer

Division of Environmental Health


Date Released: 5/7/2009
Subject: Annual Sport Harvested Mussel Quarantine 2009 Begins
Contact: Harriet Hill, Registered Environmental Health Specialist, Environmental Health Division
Phone: (707) 445-6215


The Humboldt County Department of Health and Human Services reminds the public that the annual sport-harvested mussel quarantine order has been issued by the State of California Department of Public Health. The quarantine applies to all species of mussels harvested by the public anywhere on the California coast, including all bays, inlets, and harbors.

The mussel quarantine is intended to prevent people from ingesting toxins produced by shellfish that can cause paralytic shellfish poisoning (PSP) and domoic acid poisoning (DAP). There is no known antidote to the toxins and cooking does not reliably destroy them. The vast majority of PSP illnesses in humans occur between spring and fall. To date, no human cases of DAP have been documented in California.

PSP affects the nervous system, producing a tingling around the mouth and fingertips within a few minutes to a few hours after eating the toxic shellfish. This is typically followed by disturbed balance, lack of coordination, slurred speech and difficulty swallowing. In severe cases, paralysis and death can occur.

DAP symptoms can occur within 30 minutes to 24 hours of eating toxic seafood. Mild cases may include vomiting, diarrhea, cramps, headache and dizziness. These symptoms disappear completely within several days. Severe cases can result in breathing problems, confusion, memory loss, cardiovascular instability, seizures, coma and death.

Anyone experiencing symptoms of PSP or DAP should seek immediate medical care.

Consumers of sport-harvested, bivalve (two-shelled) clams or scallops are warned to remove and discard organs or viscera and any other dark parts before cooking. Only the white meat of clams and scallops should be prepared for human consumption. As with all shellfish, clams and scallops should be taken only from areas free of sewage contamination and should also be cleaned thoroughly before cooking.

Mussels may be sold for use as bait only in containers labeled in bold-face type letters at least one-half inch in height as follows: MUSSELS FOR BAIT ONLY - UNFIT FOR HUMAN FOOD.

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.

For further information contact the Environmental Health Division at 707-445-6215 or 1-800-963-9241, or call the California Department of Public Health shellfish information line at 1-800-553-4133.


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