The California Department of Fish and Wildlife (CDFW) director has closed the recreational razor clam fishery in Del Norte County following state health agencies’ recommendation that razor clam consumption in the area poses a significant threat for domoic acid exposure.
Domoic acid is a neurotoxin produced by Pseudo-nitzschia, a naturally occurring single-celled marine alga, under certain ocean conditions. Bivalve shellfish, like clams and mussels, accumulate the toxin without harm. Razor clams are known to bioaccumulate domoic acid, which may not clear their system until long after a Pseudo-nitzschia bloom has abated.
In early November, razor clam sampling from Crescent Beach in Del Norte County found clams exceeding the current federal action level for domoic acid – greater than or equal to 20 parts per million.
Domoic acid poisoning in humans may occur within minutes to hours after consumption of affected seafood. It can result in signs and symptoms ranging from vomiting and diarrhea to permanent loss of short-term memory (Amnesic Shellfish Poisoning), coma or death. There is no way to prepare clams to remove the toxin – cooking and freezing have no effect.
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 to determine when the recreational clam fishery in Del Norte County can reopen safely.
While the recreational fishery in Humboldt County is currently open, razor clam sampling is ongoing. The fishery will be closed if domoic acid levels exceed federal action levels. CDFW reminds clammers that the daily bag limit for razor clams is 20, and the first 20 clams dug must be retained regardless of size or condition. Each person must keep a separate container for their clams and cannot communicate their take with another person when digging and transporting clams to shore.
For more information, please refer to Title 14, California Code of Regulations sections 29.20 and 29.45 for razor clam regulations that can be accessed on CDFW’s website at https://wildlife.ca.gov/Fishing/Ocean/Regulations/Sport-Fishing/Invertebrate-Fishing-Regs?utm_medium=email&utm_source=govdelivery#mollusks.
For more information on fishery closures or health advisories, please visit CDFW’s ocean health advisories website.
To get the latest information on current fishing season closures related to domoic acid, please call CDFW’s Domoic Acid Fishery Closure Information Line at (831) 649-2883.
For the latest consumption warnings, please call the California Department of Public Health’s Biotoxin Information Line at (510) 412-4643 or toll-free at (800) 553-4133.