In the first such incident in the state, the Maine Department of Marine Resources has issued a recall of clams and mussels harvested in the downeast region after testing found higher than acceptable levels of the deadly neurotoxin known as domoic acid.
“The recall applies to mussels and mahogany quahogs that were harvested or wet-stored Sunday through Friday of last week [September 25 – 30] 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.”
Domoic acid is a naturally-occurring toxin (although there is evidence that human activity may be promoting its recent widespread occurrence) produced by oceanic algae (commonly called “red tide”) that can accumulate in shellfish and fish. Although the toxin doesn't appear to harm the fish, it can cause serious illness – or even death – in humans and mammals:
“People who get sick after eating shellfish or fish tainted with this toxin can get what's called amnesic shellfish poisoning, or ASP. ASP symptoms include abdominal cramps, diarrhea, nausea and vomiting.
“Typically symptoms will appear within 24 hours after eating the meal. 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.”
There have been no reports of illness, but the recall has prompted the shutdown of shellfish harvesting on mudflats along a large stretch of the northern Maine coastline.
This is the first time that routine testing for red tide found levels of domoic acid above the safety threshold, even though the phytoplankton responsible for producing the toxin have been present in Maine coastal waters for decades.
Outbreaks on the rise in recent years
Other states have previously been affected by unsafe levels of domoic acid. The West Coast of the U.S. has had numerous problems with the toxin over the years – particularly last year when El Niño conditions caused the worst algae blooms in more than a decade.
In 2015, the crabbing season was suspended in California, Oregon and Washington after testing revealed unsafe levels of domoic acid. Washington state also had to cancel three razor clam harvesting seasons between 1991 and 2003.
In the 1980s, an outbreak caused hundreds of Canadians to become ill after eating shellfish that had been contaminated by the toxin.
The Maine Department of Marine Resources said it will continue to suspend shellfish harvesting from Otter Point to the Canadian border until the levels decrease enough to be once again considered safe.
Domoic acid can affect birds and other wildlife as well as humans. In 1998, it was proven for the first time that domoic acid can cause poisoning in marine mammals, after testing confirmed that a large outbreak had affected California sea lions.
The toxin can also affect whales, sea otters and other species.
Domoic acid: the inspiration for “The Birds”?
Interestingly, a domoic acid outbreak appears to have been the inspiration for the Alfred Hitchcock film “The Birds”. In 1961, hundreds of strangely-acting birds flew into the coastal town of Capitola, California, crashing through windows and attacking local residents. Most of the birds involved were of a species called sooty shearwaters, which are normally non-aggressive and typically only come ashore for breeding purposes.
Hitchcock was apparently fascinated by the bizarre incident, and used newspaper clippings about the story the as part of his pitch to Hollywood studios to get financing for the film, which first appeared in theaters two years later.
It is now believed that a domoic acid outbreak was responsible for the birds' crazed behavior, and thus produced what is now a curious footnote in Hollywood history.