OEHHA, in consultation with the Department of Public Health, recommends closures, delay of openings, and re-openings of fisheries, based on high levels of toxic substances, including marine biotoxins such as domoic acid, under Fish and Game Code Section 5523.
In 2015-2016, an unprecedented harmful algal bloom (HAB) event occurred in the Pacific Ocean off the west coast of the United States. A large bloom of the marine diatom Pseudo-nitzchia produced high levels of domoic acid that accumulated in some fish and shellfish species along the California coast. Domoic acid is a potent neurotoxin that can cause symptoms such as nausea, vomiting, and diarrhea at lower doses and seizures, coma, irreversible memory loss (“Amnesic Shellfish Poisoning”), and death at higher doses. No human cases of domoic acid poisoning have been reported in California; however, mild cases may not be readily recognized. Domoic acid is considered responsible for hundreds of sea lion illnesses or deaths in the state.
Since the fall of 2015, OEHHA has made numerous recommendations to close or delay the opening of Dungeness crab, rock crab, and razor clam fisheries, in various coastal locations, when levels of domoic acid exceeded the federal action level for this toxin. Recommendations for re-opening fisheries are made when domoic acid levels in successive samples fall below the action level. Closures, delay of openings, and re-openings are implemented by the California Department of Fish and Wildlife.