Susan Buckley, RN, Director, Public Health
Ira Singh, MPH, Deputy Director
Donald I. Baird, MD, Health Officer

Division of Environmental Health


Date Released: 10/30/2009
Subject: State Extends Mussel Quarantine for Humboldt, Del Norte and San Luis Obispo Counties
Contact: Harriet Hill, Registered Environmental Health Specialist
Phone: 268-2228

SACRAMENTO – The California Department of Public Health (CDPH) has announced that the statewide annual quarantine on mussels taken by sport harvesters from California’s ocean waters ends at midnight on Saturday, October 31 for all counties except Del Norte, Humboldt, and San Luis Obispo. In these three counties, samplings of mussels show detectable levels of dangerous toxins and human consumption of shellfish is not considered safe. The quarantine will be lifted when testing shows that these shellfish are safe to eat.

The annual quarantine is issued for the entire California coastline, usually from May 1 through October 31. The quarantine applies only to sport-harvested mussels. Commercially harvested shellfish are not included in the quarantine as other steps are taken to assure oysters, clams and mussels entering the marketplace are free of toxins.

Paralytic shellfish poisoning (PSP) is a form of nervous system poisoning. Concentrated levels of the PSP toxins can develop in mussels and other bivalve shellfish when they feed on certain naturally occurring marine plankton.
A second form of poisoning, Domoic Acid Poisoning (DAP) -- sometimes referred to as Amnesic Shellfish Poisoning (ASP) -- has been linked to natural food sources for filter-feeding animals like bivalve shellfish. No known cases of human ASP have occurred in California this season. Domoic acid has been linked to several poisonings of marine mammals along the Pacific Coast and may have caused several mild cases of human poisoning in the state of Washington.

CDPH’s shellfish sampling and testing programs for PSP and ASP issue warnings or quarantines when needed. The Humboldt County Division of Environmental Health, other county health departments, and various state and federal agencies participate in the monitoring program.

Consumers can receive updated information about shellfish poisoning by calling the "Shellfish Information Line" at (800) 553-4133.


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