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CDPH Lifts Warning about Razor Clams from Humboldt County

Date: August 11, 2021
Number: SN21-005
Contact: CDPHpress@cdph.ca.gov | CDPH Marine Biotoxin Monitoring Program


The California Department of Public Health (CDPH) has lifted the August 2015 shellfish safety notification related to related to sport-harvested razor clams in Humboldt County. The safety notification was issued due to dangerous levels of naturally occurring domoic acid, also referred to as Amnesic Shellfish Poisoning (ASP), 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 as well as other species of bivalve shellfish.

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.

This warning did 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.

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 ASP from domoic acid are known to have occurred from shellfish harvested in California.

For the most current information on shellfish advisories and quarantines, call CDPH's toll-free Shellfish Information Line at (800) 553-4133 or view the recreational bivalve shellfish advisory interactive map. For additional information, please visit the CDPH Marine Biotoxin Monitoring Web page.


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