The Gulf of Maine's First Massive Red Tide Stunned Coastal Mainers

By Kathryn Miles
From our April 2022 issue

Tropical storm Carrie tore through New England over Labor Day weekend in 1972, battering Cape Cod with record-setting rainfall and sustained winds of 70 miles per hour. As the storm rolled northward, it flooded Maine towns, washing away rail lines and, in at least one case, shearing a home off its foundation. By Tuesday, the storm moved on into the Maritimes. Two Mainers had drowned in the high surf, but the state had otherwise been spared the brunt. “Nothing really serious,” a Coast Gaurd spokesperson told the papers. “Just the usual aftermath of a bad storm.”

So they thought. A week later, troubling reports trickled up from Massachusetts: game wardens there had observed more than 100 dead seabirds, mostly gulls and black ducks. State scientists at first attributed the mass kill to pesticides, but scientists at the University of Massachusetts Marine Lab, near Gloucester, soon discovered a more surprising cause.

Clarice Yentsch was a new researcher at the UMass Lab. Part of her team’s investigation included daily water sampling off the dock, and she remembers one of the lab workers looking alarmed when returning from her daily collection. The sample she’d drawn resembled a cup of weak coffee, unusual for the typically clear Gulf of Maine waters. Yentsch examined the sample under a microscope and found organisms resembling a genus of marine plankton whose blooms are known colloquially as red tide. The toxic algae accumulates rapidly in shellfish such as mussels and clams. When these, in turn, are consumed by other animals — including humans — the toxins in the algae can cause paralytic shellfish poisoning, or PSP, a potentially lethal condition.

“We knew these organisms had been responsible for fatalities all over the world, but it had never before been reported in New England,” Yentsch explains today. “At that time, we had next to no information at our fingertips.”

Methods of testing for toxic algae at the time were crude but effective: researchers shucked shellfish, pureed them in a blender, then teased out a liquid sample to inject into a mouse. If the mouse lived, the shellfish were presumed safe to eat. A dead mouse meant a dangerous level of neurotoxins. The spouse of one of Yentsch’s colleagues was an elementary-school teacher who happened to have a terrarium full of mice in her classroom. He asked his wife for a few of the rodents. They died within minutes of injection. “That’s when we knew we had something very serious on our hands,” Yentsch says.

The next 72 hours were a blur, she recalls. Yentsch, who was just days away from giving birth to her second child, became part of a team of scientists in Massachusetts and Maine working around the clock to assess just how widespread the algae had become. Her team relied heavily on Maine’s state marine lab, which had already established limited shellfish testing using the mice methodology.

Spencer Apollonio, then commissioner of Maine’s Department of Sea and Shore Fisheries, remembers an all-hands-on-deck crisis, with every available state employee called on to collect sample shellfish or help transport mice from Bar Harbor’s Jackson Laboratory. What state researchers found was shocking: Maine’s first recorded red-tide outbreak was also unimaginably colossal in scale, with toxicity levels more than 100 times higher than the known safety threshold. And it was spread all up and down the state’s coastline. “We knew immediately that we had a potentially life-threatening problem, and that it would take real time to assess the full extent of the crisis,” Apollonio says.

By the time Apollonio’s team was seeing test results, 26 people in Massachusetts had already fallen dangerously ill. Every iron lung in the Bay State had been deployed to try to keep them alive. Anecdotal reports of PSP-stricken Mainers began trickling in from coastal towns as well (though the state would record no fatalities). On September 17, with then-governor Kenneth Curtis’s approval, Apollonio announced the indefinite closure of Maine’s entire coast to shellfish harvesting. For the commissioner, it was an easy call, but not everyone agreed. “There aren’t really words strong enough to describe the controversy,” Apollonio says. “Definitely the clammers weren’t so damned pleased.”

Financial losses in that industry were immediate and estimated to top $1 million per week (the equivalent of about $6.73 million today). The Bangor Daily News called the closing “an economic death knell” for coastal Maine communities. And while the federal government quickly approved small-business disaster loans for seafood markets and shellfish-processing plants, no compensation was available for the thousands of self-employed Mainers who made their livings as clam diggers, shuckers, and transporters. The shellfish industry had historically been highly individualized, Apollonio says, but workers united around the closures, with hundreds of clammers gathering to picket in Portland. Governor Curtis, along with senators Margaret Chase Smith and Ed Muskie, appealed to President Nixon for a natural-disaster declaration that would allow the shellfish workers to seek compensation.

While they waited for word from the White House, the plight of the New England fisheries became national news, with coverage on the front page of major papers, including the New York Times. With the attention came confusion over the limits of the red-tide threat. Although dangerous levels of toxins generally only appear in bivalves, news of the outbreak led lobster, crab, shrimp, and even finfish prices to tank, leaving fishermen up and down Maine’s coast with no market for their catch.

At the tail end of September, Washington approved some relief payments for shellfish workers, and shortly after, coastal flats from Cape Elizabeth to Canada reopened to limited harvesting. But it would be months before southern Maine clam diggers could return to work, and for even longer, the state’s fisheries suffered the financial effects of lagging demand.

Meanwhile, the scientific community scrambled to understand the details of the disaster. David Townsend, now a University of Maine oceanography professor, was a sophomore at the time. He recalls a general sense of confusion, from doctors uncertain about how to diagnose and treat PSP to marine biologists unable to account for red tide’s sudden presence in the state. “Nobody knew what was going on for much of that season,” he says.

It would take years for scholars like Townsend and Yentsch to explain how and why red tide appeared in Maine in 1972. The effort played a large part in leading Yentsch and her husband, the late ocean scientist Charles Yentsch, to found East Boothbay’s Bigelow Laboratory, in 1974, using $6,000 of seed money provided by Spencer Apollonio and what’s now known as the Department of Marine Resources. Research by Bigelow, UMaine, the state, and other entities has since confirmed that blooms of the toxic algae are widespread in the deep waters of the North Atlantic continental shelf. Historically, Maine’s prevailing westerly winds have created ocean currents that keep such plankton offshore, but the cyclonic action of Tropical Storm Carrie helped funnel that algae towards the coast. At the same time, flooding caused by the storm increased terrestrial runoff, and the fertilizers it contained fed the algae, causing it to proliferate.

Because algal seeds, known as cysts, have remained offshore since being introduced in ’72, red tides have occurred periodically in the Gulf of Maine ever since, including an even more severe bloom in 2005. But ocean scientists’ new understanding has allowed them to begin forecasting future red-tide outbreaks. After 1972, Maine launched substantial biotoxin-monitoring programs, and today, temporary shellfish closures are commonplace. Other ripple effects, Yentsch says, extend well beyond the marine-biology community.

“So many ideas became newly recognized because of this outbreak,” she says, “including the ideas that the more our weather patterns change and the more we pollute our waters with fertilizers, the more potential we’ll have for future events.”

The lessons learned, Yentsch says, are as relevant for contemporary crises as they were 50 years ago. “All of us — the medical professionals, the clammers, the public, the scientists, and knowledge seekers — were utterly surprised by the outbreak,” she says. “There was so much we didn’t know, from how to test to how best to keep the public safe. It took individual communities being willing to come together to share experiences and being willing to change for us to begin to find real answers.”