CDPH Lifts Warning for Some Sport-Harvested Bivalve Shellfish from Humboldt County
SN25-024
What You Need to Know: CDPH has removed warnings that advised against eating certain types of recreationally harvested bivalve shellfish from the waters of Humboldt County. A warning against eating sport-harvested razor clams from Humboldt County remains in effect as does the annual mussel quarantine for recreationally harvested mussels along the entire California coast.
SACRAMENTO – The California Department of Public Health (CDPH) has lifted the shellfish and seafood safety notification today related to certain sport-harvested bivalve shellfish from Humboldt County. The warning no longer applies to scallops, oysters and clams (except for razor clams). An advisory for razor clams in Humboldt County remains in effect.
The safety notification for Humboldt County was issued on
September 9, 2025, due to dangerous levels of domoic acid in mussels. This naturally occurring toxin can cause illness or death in humans. Recent testing shows domoic acid has decreased to safe levels in shellfish other than razor clams in this area.
A
warning against eating sport-harvested razor clams from Humboldt County remains in effect as razor clams are a high risk for long-term elevated levels of domoic acid. Dangerous levels of naturally occurring domoic acid, also referred to as amnesic shellfish poisoning, have been detected in the razor clams. Razor clams are known to retain domoic acid toxin in their meat and tissues much longer than other species of bivalve shellfish.
The
annual mussel quarantine also remains in effect, which means that while scallops, oysters, and most types of clams can be harvested from Humboldt 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.
This warning does not apply to commercially sold mussels, clams, scallops, or oysters from approved 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.
Symptoms of amnesic shellfish poisoning can occur within 30 minutes to 24 hours after eating toxic seafood. In mild cases, symptoms may include vomiting, diarrhea, abdominal cramps, headache, and dizziness. These symptoms disappear within several days. In severe cases, the victim may experience trouble breathing, confusion, disorientation, cardiovascular instability, seizures, excessive bronchial secretions, permanent loss of short-term memory, coma, or death.
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.