​CDPH Lifts Warning about Razor Clams from Humboldt County​

Date: August 3, 2023
Number: SN23-008
Contact: CDPHpress@cdph.ca.gov

The California Department of Public Health (CDPH) has lifted the shellfish safety notification related to sport-harvested razor clams in Humboldt County. The safety notification was issued on October 27, 2022, and extended January 9, 2023, due to dangerous levels of naturally occurring domoic acid, also referred to as Amnesic Shellfish Poisoning, that can cause illness or death in humans. Recent testing shows concentrations of domoic acid are now at safe or undetectable levels in razor clams.

Razor clams are known to retain domoic acid toxin in their meat and tissues much longer than other species of bivalve shellfish. Domoic acid was present in the razor clams due to the occurrence of toxin-producing marine phytoplankton. Razor clams have been continually tested and have now met the criteria for lifting the safety notification in Humboldt County.

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. No cases of human amnesic shellfish poisoning from domoic acid are known to have occurred from shellfish harvested in California.

This notification 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. ​