The state Department of Marine Resources issued a recall notice Friday for certain mussel and clam harvests after they tested positive for unsafe levels of a neurotoxin that causes brain damage in humans.

The recall applies to mussels and mahogany quahogs harvested or wet-stored Sunday through Friday in the Jonesport area, and clams harvested Wednesday through Friday in the area from Cranberry Point in Corea to Cow Point in Roque Bluffs.

Department spokesman Jeff Nichols said the recall is based on testing of mussel and clam samples, and that no cases of illness from eating the tainted shellfish have been reported.

The samples tested exceeded the established threshold of 20 parts per million of domoic acid from the phytoplankton Pseudo-nitzschia. When shellfish eat the plankton, the acid can build up inside their systems.

Domoic acid acts as a neurotoxin when ingested by mammals, including humans. It can cause permanent short-term memory loss, brain damage and even death in severe cases. The phenomenon is known as amnesic shellfish poisoning.

The department instructed all shellfish dealers in possession of the affected mussels and clams to dispose of them immediately.

Nichols said the phytoplankton containing the acid has existed in Maine waters for decades, but that this was the first time any shellfish have tested above the safety threshold. The department has no theories on why it happened this time, he said.

“There have been no illnesses ever attributed to (amnesic shellfish poisoning) from Maine shellfish,” Nichols said.


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