California's Annual Mussel Quarantine

From March through October, a quarantine is placed on all sport-harvested mussels in California. The quarantine is designed to protect the public from elevated levels of domoic acid and paralytic shellfish poisoning. See the 2011 press release here.

In 2009, the quarantine was lifted on October 28. In Monterey Bay, the Fall-Winter Model predicted increases in mussel toxicity for September and October and continued through December. From October 19 througb December 22 toxic shellfish, with domoic acid exceeding regulatory limits, were present at the Santa Cruz Municipal Wharf as detected through weekly analysis. A press release was issued on November 13, warning consumers not to eat sport-harvested shellfish in Santa Cruz County. The model had correctly predicted the prolonged toxicity event before the weekly mussel samples contained elevated levels of domoic acid.

 

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This timeline shows domoic acid in shellfish as measured by the California Department of Public Health (CDPH) and the model bloom predictions. In 2009, the model prediction (green line) increases before the sentinel shellfish DA concentrations, and the shellfish DA exceeds regulatory limits after the annual quarantine ended.

This timeline shows the CDPH domoic acid screening index. In 2009, the screening index showed zero DA (red arrows) just before DA exceeded regulatory limits. Figures courtesy of J. Lane.