Update: The California Department of Public Health has lifted the April 4 and April 28 health advisories warning consumers not to eat recreationally harvested bivalve shellfish or the internal organs of commercially or recreationally caught anchovy, sardines, or crab taken from Monterey and Santa Cruz counties.
Recent testing shows concentrations of domoic acid have declined to safe or undetectable levels. Domoic acid is a naturally occurring nerve toxin that can cause illness or death in humans. There have been no reported illnesses associated with these events.
The California Department of Public Health had advised consumers not to eat this seafood back in April from Monterey and Santa Cruz counties.
State health officials say dangerous levels of domoic acid were detected in some of these species and could be present in others. Anchovy and sardines are of concern because the toxin resides in their digestive tracks, and these fish aren't usually gutted before they are eaten.
The health department worked with commercial fishers in the region to ensure recently-caught sardines, anchovies and crab aren't distributed into the human food supply.
While these two health advisories have been lifted, the annual quarantine of sport-harvested mussels remains in effect for the entire California coast, including all bays and estuaries.
This quarantine, which went into effect May 1, is intended to protect the public from paralytic shellfish poisoning and domoic acid poisoning. Both of these toxins are linked to plankton consumed by filter-feeding animals such as bivalve shellfish, like mussels and clams.
Commercially harvested shellfish are not included in the annual quarantine. All commercial shellfish harvesters in California are certified by the state and subject to strict testing requirements to ensure that all oysters, clams and mussels entering the marketplace are free of toxins.
State health officials will continue to collect bivalve shellfish, fin fish and crab samples from the area to monitor the level of domoic acid in seafood.
There have been no reported illnesses at this point.
Domoic acid poisoning symptoms can occur within a half-hour to 24 hours of eating toxic seafood, and symptoms can range from vomiting and diarrhea to breathing troubles, permanent loss of short-term memory or even death.
Early symptoms of PSP include tingling of the lips and tongue, which may begin within minutes of eating toxic shellfish. These symptoms are typically followed by a loss of balance, lack of muscular coordination, slurred speech and difficulty swallowing. In severe poisonings, complete muscular paralysis and death from asphyxiation can occur.
For updated information about shellfish poisoning and quarantines, call the California Health Department's toll free shellfish information line at 800-553-4133 or visit the agency's Natural Marine Toxins: PSP and Domoic Acid Web page.