Dr. Mark Horton, director of the California Department of Public Health (CDPH), announced today that the statewide annual quarantine on mussels taken by sport harvesters from the ocean waters of California for human consumption ends at midnight on Oct. 31. Sampling of mussels confirmed that shellfish-borne paralytic shellfish poisoning toxins and domoic acid 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. The quarantine applies only to sport-harvested mussels.
No commercially harvested shellfish are included in the annual quarantine. All commercial shellfish harvesters in California are certified by the state and subject to strict requirements to ensure that all oysters, clams and mussels entering the marketplace are free of toxins. Commercial harvesting is stopped immediately if potentially dangerous levels of toxins are found.
Paralytic shellfish poisoning (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.
Domoic acid poisoning (DAP) has been linked in some cases to natural food sources for filter-feeding animals like bivalve shellfish. To date, no known cases of human DAP have occurred in California; but domoic acid has been linked to several episodes of severe poisoning 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 program for PSP and DAP issues warnings or establishes special quarantines when needed. Local health departments, various state and federal agencies and others participate in the monitoring program.
Consumers can receive updated information about PSP and DAP by calling the CDPH "Shellfish Information Line" at 1-800-553-4133.