Deadly neurotoxin causes recall of Maine’s mussels and clams

Blog_ClamsThe deadly neurotoxin believed to infect hundreds of birds in 1961 and inspire the Alfred Hitchcock movie “The Birds,” has been reported by Maine’s Department of Marine Resources and has resulted in the recall of mussels and clams harvested within the state.

Known as domoic acid, this marine biotoxin is secreted by algal blooms, and causes amnesic shellfish poisoning (ASP) in humans and other mammals, including birds, who consume infected fish. While it doesn’t seem to actually harm the fish it infects, ASP symptoms for humans who consume the fish include abdominal cramps, diarrhea, nausea and vomiting.

Typically symptoms of ASP will appear within 24 hours after eating infected fish. If someone eats enough of the toxin at a high enough level, it can cause neurological problems including short-term memory loss, seizures, dizziness, motor weakness, headache, seizures, cardiac arrhythmia, coma and even death.

Some of these symptoms were reportedly seen in birds, which attacked people and dived through windows and crashed into trees in Capitola, California, inspiring the well-known Hitchcock movie.

While there has been no reported cases of illness linked to this recall as of yet, it applies to mussels and mahogany quahogs that were harvested or wet-stored Sunday through Friday of last week in the Jonesport area of Maine, and clams that were harvested last Wednesday through Friday from Cranberry Point in Corea to Cow Point in Roque Bluffs. Freezing or cooking of the infected fish does not seem to reduce the danger.

The Maine Department of Marine Resources said the phytoplankton that creates the neurotoxin has been in the waters around the state for decades, but this is the first time shellfish in the area has tested positive for a toxin above the safety threshold.

Jeff Nichols, director of communications for the Maine Department of Marine Resources, said this is the first time Maine has issued a recall because of this toxin and has told dealers to throw out any clams and mussels harvested from this specific time period. This is also the first time the state has closed any part of the coast to harvesting mussels and soft-shell clams. The closure began on September 27 and expanded over the ensuing days, with closures stretching from Otter Point to the Canadian border.

“The recall, combined with the closure to harvesting, gives us every confidence that we have taken all the necessary steps to prevent impacted shellfish from making it to the public,” Nichols said in an article.

Maine is not the only state to have struggled with problems caused by domoic acid. The toxin has showed up in marine animals as far away as Alaska, and an outbreak in Canada in the 1980s caused hundreds of people to get sick after eating mussels with a high concentration of the chemical.

Last year, after El Niño warmed the ocean waters, the perfect environment was created for the toxin to develop especially throughout the West Coast, which saw one of the largest harmful algal blooms in more than a decade. That caused crabbing season to be closed in Washington, California and Oregon. The toxin has been blamed for the death of whales and other sea life as well.

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Neogen offers seafood and shellfish analysis test kits to detect various marine biotoxins including amnesic shellfish poisoning. For more information, click here.

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