Dangerous levels of domoic acid, also referred to as Amnesic Shellfish Poisoning, have been detected in mussels from Humboldt County. The naturally occurring domoic acid toxin can cause illness or death in humans. Cooking does not destroy the toxin.  

This shellfish safety notification is in addition to the warnings against eating sport-harvested bivalve shellfish in Humboldt County due to paralytic shellfish poisoning toxins and sport-harvested razor clams from Humboldt County due to domoic acid. The annual mussel quarantine is also in effect. 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. 

Symptoms of amnesic shellfish poisoning 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 within several days. In severe cases, the victim may experience trouble breathing, confusion, disorientation, cardiovascular instability, seizures, excessive bronchial secretions, permanent loss of short-term memory, coma, or death.  

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.  ​