Mussels on the rock. Photo: Wikimedia.

From the California Department of Public Health:

The California Department of Public Health (CDPH) advises consumers not to eat recreationally harvested mussels, clams or whole scallops from Humboldt County. Dangerous levels of paralytic shellfish poisoning (PSP) toxins have been detected in mussels from this region. The naturally occurring PSP toxins can cause illness or death in humans. Cooking does not destroy the toxin. 

This advisory expands the area mentioned in CDPH’s February 8 warning about bivalve shellfish from Tomales Bay and Humboldt Bay. 
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. 

Consumers are also reminded to avoid consumption of crab viscera from crabs caught in the affected area as crabs do consume bivalve shellfish and could accumulate some of the PSP toxin in their gut. Crab meat is not affected by PSP toxin.

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. There have been no reports of illnesses related to this event.

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. For additional information, please visit the CDPH Marine Biotoxin Monitoring Web page.