SACRAMENTO - The quarantine on mussels taken by sport harvesters from the ocean waters of San Luis Obispo County for human consumption has been lifted, State Public Health Officer Dr. Mark Horton announced today. Extensive sampling of mussels confirmed that shellfish-borne paralytic shellfish poisoning (PSP) toxins are at safe or undetectable levels.

The quarantine is issued for the entire California coastline, usually from May 1 through Oct. 31, to protect consumers of sport-harvested shellfish from PSP and domoic acid poisoning. The quarantine was lifted on Oct. 31 for all coastal counties except San Luis Obispo because elevated levels of the PSP toxins were detected in shellfish gathered along its coastline.

The annual quarantine applies only to sport-harvested mussels. Commercial shellfish harvesters in California must be certified by the California Department of Health Services (CDHS) and are subjected to stringent sample testing for toxins. Commercial harvesting is stopped immediately if a potentially dangerous level of toxin is found.

PSP is a form of nervous system poisoning. Concentrated levels of the PSP toxins can develop in California mussels and other bivalve shellfish when they feed on certain naturally occurring marine plankton. Shellfish become toxic only when populations of the responsible organism, a dinoflagellate known as Alexandrium catenella, become abundant in ocean waters -- a phenomenon known as a "bloom." Bivalve shellfish feed by filtering the microscopic organisms from the water and concentrate the toxin in their bodies.

Consumers can receive updated information about PSP and domoic acid by calling CDHS' "Shellfish Information Line" at 1-800-553-4133.

-oOo-