SACRAMENTO – The California Department of Public Health (CDPH) is advising consumers not to eat sport-harvested mussels, clams, scallops, or oysters from Marin and San Mateo Counties.   

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

PSP toxins affect the 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 mussels, clams, scallops, and 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.  ​