Dangerous levels of paralytic shellfish poisoning (PSP) toxins have been detected in mussels from Marin County. The naturally occurring PSP toxins can cause illness or death in humans. Cooking does not destroy the toxin.   

This shellfish safety notification is in addition to the annual mussel quarantine. The annual quarantine applies to all species of mussels harvested for human consumption along the California coast, as well as all bays and estuaries, and will continue through at least October 31.  

PSP toxins affect the 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 are typically followed by loss of balance, lack of muscular coordination, slurred speech, and difficulty swallowing. In severe poisonings, complete muscular paralysis and death from asphyxiation can occur.   

 This warning does not apply to commercially sold clams, mussels, scallops, or oysters from approved sources. State law permits only state-certified commercial shellfish harvesters or dealers to sell these products. Shellfish sold by certified harvesters and dealers are subject to frequent mandatory testing to monitor for toxins. ​

You can get the most current information on shellfish advisories and quarantines by calling CDPH’s toll-free Shellfish Information Line at (800) 553-4133 or viewing the recreational bivalve shellfish advisory interactive map. For additional ​information, please visit the CDPH Marine Biotoxin Monitoring Web page.