California public health officials issued a warning on April 30th, alerting the public that clams collected along the coastline contain dangerous toxins that could lead to severe shellfish poisoning, even death.
The California Department of Public Health has issued this year’s shellfish monitoring order, covering any type of clams collected by recreational harvesters from the California coast from May 1st to October 31st.
During this period, clams collected are not to be consumed by anyone, according to the health department.
The Los Angeles County Department of Public Health noted that the regulated area includes the California coast (from the Oregon border to the Mexico border, including all bays, estuaries, and harbors in Los Angeles County).
According to state government reports, if testing reveals dangerous levels of biotoxins still present in clams after the regular monitoring period, the ban for that year may be extended.
The health department stated that the annual shellfish monitoring period is established to prevent the public from collecting clams during high-risk marine toxin periods.
Clams collected from May to October may contain high concentrations of natural toxins, including the highly toxic paralytic shellfish toxins and domoic acid biotoxins.
Shellfish feed on various algae and other food particles. When they consume algae that proliferate in the summer and produce toxins, the toxins accumulate in the shellfish tissue.
Health officials say early symptoms of paralytic shellfish poisoning include tingling or numbness in the lips and tongue, which may occur within minutes to hours after consumption. Subsequent symptoms typically include loss of balance, decreased muscle coordination, slurred speech, and difficulty swallowing.
In severe cases, without prompt treatment, full-body muscle paralysis and even death from suffocation can occur.
Domoic acid poisoning, also known as amnesic shellfish poisoning, can occur between 30 minutes to 24 hours after consuming contaminated seafood. Mild symptoms include vomiting, diarrhea, abdominal cramps, headache, and dizziness.
Health officials note that severe cases may involve difficulty breathing, confusion, disorientation, cardiovascular instability, seizures, excessive bronchial secretions, permanent short-term memory loss, coma, or even death. There is currently no antidote for this toxin, but most cases generally recover fully within a few days.
If consuming clams or scallops, it is recommended to discard the digestive organs (viscera) and dark parts of the seafood, and only consume the white muscle part.
The health department emphasizes that shellfish from areas affected by sewage or chemical contamination should not be collected for consumption.