Domoic Acid Poisoning: How Razor Clams are Hitting California Fisheries Hard

Razor clams are known to bioaccumulate domoic acid, a potent neurotoxin produced by naturally occurring, single-celled marine alga. In Humboldt County, California, recent sampling of razor clams from Clam Beach found levels exceeding the federal action level for domoic acid. This has prompted the California Department of Fish and Wildlife (CDFW) Director Charlton H. Bonham to close the recreational razor clam fishery in the area.

Domoic acid poisoning in humans can occur within minutes to hours after consumption of affected seafood and can result in symptoms ranging from vomiting and diarrhea to permanent loss of short-term memory (Amnesic Shellfish Poisoning), coma or death. Unfortunately, there is no way to prepare clams for consumption that will remove the toxin – cooking and freezing have no effect.

The recreational razor clam fishery in Del Norte County remains closed due to elevated levels of domoic acid as well. The closure began in November 2023 and will remain in effect until state health agencies determine that razor clams no longer pose a health risk. The CDFW will continue to work with the California Department of Public Health (CDPH) and Office of Environmental Health Hazard Assessment to collect, monitor and analyze razor clams until they can be reopened safely in these areas.

For more information on any fishery closure or health advisories, please visit www.wildlife.ca.gov/Fishing/Ocean/Health-Advisories