The California Department of Public Health has issued the yearly Mussel Quarantine Order effective May 1 through October 31, 2023. The mussel quarantine prohibits the public from harvesting mussels for human consumption due to paralytic shellfish poisoning and domoic acid poisoning. The quarantine applies only to sport-harvested mussels. Other types of bivalve shellfish, including oysters and clams, and commercially harvested mussels from certified companies are not included in the quarantine.