The recreational razor clam fishery in Humboldt County has been closed by the California Department of Fish and Wildlife (CDFW) Director Charlton H. Bonham, after health agencies found that consuming razor clams in the area poses a significant threat for exposure to domoic acid, a potent neurotoxin produced by the marine alga Pseudo-nitzschia under certain ocean conditions.
The closure of the recreational razor clam fishery in Del Norte County has also been extended since November 2023 due to elevated levels of domoic acid. This decision was made after state health agencies found that consumption of razor clams in both counties could lead to poisoning symptoms ranging from vomiting and diarrhea to permanent loss of short-term memory, coma or even death.
Bivalve shellfish like clams and mussels are known to accumulate the toxin without being harmed. Razor clams, in particular, are known to bioaccumulate domoic acid, meaning the toxin may not clear their system until long after the ocean conditions that caused it have abated. As a result of sampling in late April, razor clams from Clam Beach in Humboldt County were found to exceed the federal action level for domoic acid of greater than or equal to 20 parts per million.
Cooking and freezing clams have no effect on removing the
