CDPH Lifts Warning for Sport-Harvested Bivalve Shellfish from Marin County

July 30, 2025

The California Department of Public Health (CDPH) has lifted the shellfish safety notifications today related to sport-harvested bivalve shellfish from Marin County. 

The safety notification for Marin County sport-harvested bivalve shellfish was issued on June 19, 2025, due to dangerous levels of paralytic shellfish poisoning toxins in mussels. These naturally occurring toxins can cause illness or death in humans. Recent testing shows paralytic shellfish poisoning toxins have decreased to safe or undetectable levels for bivalve shellfish in this area.   

The warning that has been lifted did not apply to commercially sold mussels, clams, scallops, or oysters from approved commercial sources. State law permits only state-certified commercial shellfish harvesters or dealers to sell these products. Shellfish sold by certified harvesters and dealers are subject to frequent mandatory testing to monitor for toxins.

Paralytic shellfish poisoning toxins affect the nervous system, producing a tingling around the mouth and fingertips within a few minutes to a few hours after eating toxic shellfish. These symptoms are typically followed by loss of balance, lack of muscular coordination, slurred speech and difficulty swallowing. In severe poisonings, complete muscular paralysis and death from asphyxiation can occur.

While this warning has been lifted, the annual mussel quarantine remains in effect, which means that while scallops, clams, and oysters can be harvested from Marin County, mussels remain under quarantine. The annual quarantine prohibits the sport harvest of mussels for human consumption and applies to all species of mussels harvested along the California coast, as well as all bays and estuaries, and will continue through at least October 31.

For the most current information on shellfish advisories and quarantines, call CDPH’​s toll-free Shellfish Information Line at (800) 553-4133 or view the recreational bivalve shellfish advisory interactive map. For additional information, please visit the CDPH Marine Biotoxin Monitoring web page.