Skip Navigation LinksNR15-031

Annual Quarantine of Sport-Harvested Mussels in California Begins May 1 

Date: 4/28/2015 
Number: 15-031 
Contact: Anita Gore,  Orville Thomas (916) 440-7259 

Sacramento – The annual quarantine on sport-harvested mussels gathered along the California coast begins May 1, announced Dr. Karen Smith, director of the California Department of Public Health (CDPH) and state health officer. This quarantine applies to all species of mussels harvested along the California coast, as well as all bays and estuaries. 

This quarantine is intended to protect the public from paralytic shellfish poisoning (PSP) and domoic acid poisoning (DAP). Both of these toxins are linked to plankton consumed by filter-feeding animals such as bivalve shellfish, like mussels and clams. The majority of human cases of PSP illnesses occur between spring and fall. 

“This quarantine protects the public from severe illness, including coma and death,” said Smith. “There is no known antidote to the toxins that have been found in mussels, and these toxins cannot be reliably destroyed by cooking. We appreciate the public honoring the quarantine. It’s very important to protect yourself from what could be a very serious illness.” 

Commercially harvested shellfish are not included in the annual quarantine. That’s because all commercial shellfish harvesters in California are certified by the state and subject to strict testing requirements to ensure that all oysters, clams and mussels entering the marketplace are free of toxins. 

Early symptoms of PSP include tingling of the lips and tongue, which may begin within minutes of 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. 

Symptoms of DAP, also known as amnesic shellfish poisoning (ASP), 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 difficulty breathing, confusion, disorientation, seizures, permanent loss of short‑term memory, coma and death. Anyone experiencing any of these symptoms should consult a physician immediately.

More information about the quarantine, PSP and DAP can be found on the CDPH Annual Mussel Quarantine - Frequently Asked Questions (FAQ) Web page

For updated information on quarantines and shellfish toxins, call the CDPH Biotoxin Information Line (1-800-553-4133).
Page Last Updated :