A ‘forbidden experiment,’ two moonshots and the invasive species ravaging the Great Lakes

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Politicians recently received an old enemy at the Capitol.

Half a dozen guests arrived fresh from their journey from the Great Lakes. They flashed their teeth for the cameras and posed alongside policymakers from Florida to California. There were no handshakes, but one did suck on the palm of Representative Bill Huizenga.

“It definitely gets your attention,” said the House member from Michigan.

In a Congress riven by divides as deep and chilly as the Great Lakes themselves, both sides of the aisle agree: invasive sea lampreys must go.

“I’ve been in politics in one element or another for my entire life,” said Greg McClinchey, director of policy and legislative affairs at the Great Lakes Fishery Commission (GLFC). “I have never had an issue that unifies like this.”

The June meet and greet was the latest organized by the GLFC to remind policymakers that this threat only remains dormant because of government funding, from both the US and Canada.

In pictures: Invasive species around the world

11 photos

A parasitic sea lamprey, native to the Atlantic Ocean but invasive to the Great Lakes, bares its teeth. Scroll through the gallery to see more of the planet’s most problematic invasive species.

In pictures: Invasive species around the world

A parasitic sea lamprey, native to the Atlantic Ocean but invasive to the Great Lakes, bares its teeth. Scroll through the gallery to see more of the planet’s most problematic invasive species.

Warty comb jelly —

The humble comb jelly has no brain, stomach or bones. It eats microscopic sea organisms, as well as fish eggs and larvae. Native to the Atlantic coasts of North and South America, warty comb jellies reached the Black Sea, Aegean Sea and Caspian Sea during the 1980s. The jellies traveled across oceans in the ballast water of ships. In these new waters, they flourish thanks to a lack of natural predators. It is associated with crashes in fish numbers. Dolphin populations, dependent on fish supplies, have plummeted in the Black and Azov Seas as a result of the jelly invasion, according to the World Wildlife Fund.

Cane toad —

These creatures are indigenous to South America. They were deliberately introduced to many countries in the 1930s (including the USA and Australia) to help control sugar cane pests, like beetles. But cane toads proved to be disastrously voracious, eating anything from honeybees to dog food. An estimated 1.5 billion cane toads live in Australia alone. When attacked or eaten, they emit venom that can be fatal to wild animals and household pets alike. Studies in Bermuda show they are outcompeting native frogs.

Asian longhorn beetle —

Trees where these beetles lay their eggs are doomed to a slow death, as larvae gnaw away at their bark from the inside. Native to Asian countries including China and Japan, this species has reached Europe and North America, mostly through wooden packaging. They have already infested many poplar plantations in China, and have also been found in chestnut trees, willows and elms. The US Department of Agriculture has warned that the insects could devastate American timber industries and forests if left unchecked.

Stoat —

Related to weasels, polecats and ferrets, the stoat is a small but ferocious predator. Stoats have no qualms about attacking larger animals, including rabbits and chickens. European settlers took stoats to New Zealand for pest control purposes, where they wreaked havoc on native bird populations. The New Zealand government spends millions of dollars each year protecting native birds from stoats, which feast on their chicks and eggs.

European Starling —

Sixty of these birds were set free in New York in 1890, in a bizarre plan to introduce to the USA every bird mentioned in a Shakespeare play. European Starlings were also deliberately introduced to regions of Australasia and South Africa to control native insect populations. Today, between 100 million and 200 million Common Starlings on six continents destroy many crops, and out-compete birds like woodpeckers in the United States and black cockatoos in Australia. However, their numbers appear to have fallen in recent decades, possibly due to intensive farming techniques.

Giant African land snail —

Its native range is coastal East Africa, but this snail has reached all continents except Antarctica. They are sold as food, pets, and for medicinal purposes, which led to their accidental introduction to the wild. In New Zealand, the Giant African land snail eats many types of local snails, as well as native plants.

Red deer —

This large deer species was brought from Europe and Western Asia to Australia, New Zealand and South America, for trophy hunting and livestock. It flourishes in a wide range of habitats and can outcompete native mammals searching for food.

Common prickly pear —

Originally from the Americas, this cactus is an invasive species in South Africa, Kenya and Australia. It grows in bristly thickets up to two meters high, and was often introduced to contain livestock. It is highly drought and frost resistant, and can spread across millions of hectares of land. During an infamous spell dubbed “the green hell” in Australia in the 1920s, the cacti spread so rapidly and thickly across rural plains that people abandoned their homes and farms. The plants were tamed when authorities introduced a foreign cactus gourmet, the cactoblastis moth, in 1925.

Water hyacinth —

These purple-blossoming plants can spread to cover every inch of a lake, blocking out sunlight and crowding out native plants. The water hyacinth most likely originated in Brazilian rainforests, and became a popular addition to garden ponds worldwide in the 1890s. But this formidable species can double its size in a fortnight. The flowers, pictured here in Dhaka, Bangladesh, are now found on every continent except Antarctica.

Black rat —

Also known as the ship rat, it is native to India but over thousands of years, it spread to every continent except Antarctica by hiding in ships. These furry stowaways can devastate wildlife populations as they guzzle through native insects, bird eggs and chicks, and fruit.

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In pictures: Invasive species around the world

The invasive species, native to the Atlantic Ocean, has plagued the Great Lakes since entering Lake Ontario the mid-1800s, before moving into the upper Great Lakes in the 1920s. It had a devastating impact on the lakes’ trout, salmon and whitefish populations.

Sea lampreys don’t have a vampiric reputation for nothing. They are a parasite, latching on to fish with their suction cup mouth and rings of teeth. They don’t eat flesh but suck their prey dry, reducing it to a husk. One lamprey consumes around 40 pounds (18 kg) of fish in 12-18 months, and females can lay 100,000 eggs in a single spawning season.

The commission was established by a treaty signed between the US and Canada in 1954 partly to mitigate the lamprey problem. A moonshot project to control the population succeeded in 1957, when a chemical compound was developed called TFM (3-trifluoromethyl-4-nitrophenol), which kills lamprey larvae, without harming native fish. Since then, “lampricide” has been applied from spring to fall to spawning areas in lake tributaries, killing young lampreys before they can enter the lakes, beyond the reach of scientists.

A sexually mature sea lamprey, identified by the ridge along its back.

A fisher holds up their catch, carrying a wound caused by a lamprey.

If left uncontrolled, it’s estimated lampreys could collapse the Great Lakes’ fish stocks — and with it, a multibillion-dollar fishing industry — in just five years, says the GLFC.

Around 9 million need to be killed every year just to prevent a population explosion. Eradicating invasive lampreys entirely “is a very real possibility we continue to work towards,” said McClinchley, but “not something that’s on the cards today.”

In fact,seven decades after the moonshot, all that good work was nearly undone. Worse still, new invasive species have arrived — and controlling them may require another moonshot.

‘The forbidden experiment’

The GLFC has only recently recovered from Covid-19. During lockdown in 2020 and 2021, staff had to maintain social distance, which meant fewer treatments took place and the commission was unable to implement its full control program.

The lamprey population “skyrocketed” by 300% in some areas, said McClinchley. “It did make (our) case.”

“We call it ‘the forbidden experiment’ here in the office,” he added. “We have always said that if we don’t keep controlling sea lamprey that they will bounce back — they’re a coiled menace. But we never dared to do (it).”

A worker treats water with lampricide, targeting sea lamprey larvae.

The GLFC says fishing on the Great Lakes supports 75,000 jobs, and estimates the rise in lampreys during the pandemic caused a $2 billion hit to the economy.

“That squares with what our members lived through,” said Vito Figliomeni, executive director of the Ontario Commercial Fisheries’ Association. Figliomeni, who is a strong supporter of lamprey control and advises the GLFC, said commercial fishers saw more marked and damaged fish from lampreys, and more pressure on fish stocks during the pandemic.

“For family operators working on thin margins, ($2 billion) isn’t an abstraction — it’s income, and it’s the question of whether the next generation stays in business,” he added.

A deckhand aboard a commercial fishing boat on Lake Erie in Port Stanley, Ontario, Canada, on Aug. 22, 2018.

Through subsequent lampricide treatments the problem was reined in by the GLFC. In December 2025 it announced it had reduced sea lamprey numbers to pre-pandemic levels, though in Lake Superior the population remained elevated.

The Covid-19 crisis highlighted that even with effective solutions, the Great Lakes remain precariously balanced.

Lampricide works because the larvae are unable to metabolize the compound, which disrupts their energy production, resulting in death. Nearly 70 years after its introduction, there’s no sign that lampreys have developed any resistance to it, says the GLFC.

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That has not stopped the commission from searching for alternative controls, which make use of dams, bubble barriers and acoustic barriers in rivers around the lakes. The GLFC is also employing a novel concept called FishPass to replace the Union Street Dam in Traverse City, on the edge of Lake Michigan.

Construction of a replacement for the Union Street Dam in Traverse City, Michigan. The new dam will feature a channel that will be kitted with technology to identify and prevent invasive sea lampreys from moving upstream.

The new dam will extend over the Boardman River, with a channel alongside it for select fish to pass up and downstream. The under-construction channel will be equipped with various ways of filtering out lampreys, containing them and preventing them from moving upstream.

The goal is for the process to be fully automated, said McClinchley, who added that the GLFC is investigating a variety of technologies, including video shape recognition, to see which work best, before rolling out a combination on the channel.

Can one moonshot inspire another?

Sea lampreys are only one of 186 invasive species among 3,000 species in the Great Lakes.

Some have found a use. Rainbow smelt was accidentally introduced in the early 1900s and became the largest quota species in Lake Erie, according to the Great Lakes Foods Company of Chatham, Ontario, which exclusively fishes for smelt.

Others, like the quagga mussel and zebra mussel, are a plague. The mussels arrived in ballast water from commercial vessels in the 1980s, and since then have impacted the survival of fish eggs, caused toxic algae blooms, and outcompeted native mussels. There’s currently no way to safely eliminate them from the Great Lakes.

Zebra mussels near Kingston, Canada, which have invaded Lake Ontario. Zebra and quagga mussels invaded the Great Lakes in the 1980s, arriving aboard cargo ships.

“Zebra and quagga mussels have done more damage to our members’ livelihoods than almost anything else on the lakes,” said Figliomeni.

“They strip the nutrients and plankton out of the water column and collapse the food web that whitefish and other species depend on. In Lake Huron, the whitefish decline has tracked almost in lockstep with the rise in mussel biomass.”

Invasive mussels are also a suspected factor in the rise of avian botulism die-offs in recent decades. They concentrate botulism, and another invasive species, the round goby, eats the mussels. Scientists have theorized that poisoned gobies become paralyzed and easy prey for birds, which then die from the toxin.

Legislation is before Congress that would task the commission with finding a control. The bipartisan bill, dubbed the “Save Great Lakes Fish Act of 2025,” proposes a $500 million budget spread across 10 years to find a solution.

Figliomeni said an effective control “would be genuinely transformative” for the lakes’ fishers: “It’s the difference between managing a decline and actually having a shot at reversing it.”

On June 3, the US-Canadian Committee of Advisors to the GLFC — a group consisting of Indigenous, commercial, recreational, academic, agency, environmental, and public fishery interests — unanimously passed a resolution supporting the act, and urged the US Congress to pass the legislation into law.

There is no timeline for when, or if, Congress will act, said McClinchley.

Fishing on the Great Lakes has weathered the storms of parasitic sea lampreys. Now invasive mussels pose an existential threat.

“We need Congress to make a decision … Once that happens, our commissioners have already signaled their desire to help find a ‘second moonshot,’” he said.

Representative Huizenga, who is also co-chair of the Bipartisan Great Lakes Task Force, said, “The Great Lakes aren’t a Republican issue or a Democratic issue. They’re an economic engine, a source of drinking water for millions of people, and part of our way of life here in Michigan. Protecting them is something we can all rally around.”

Should the second moonshot succeed, it could have implications beyond the Great Lakes, for a blight spreading though freshwater bodies across North America and Europe. But how to achieve it remains uncertain.

Back in the 1950s, scientists conducted pickle jar experiments to find ways to kill lampreys. That wasn’t hard, said McClinchley. Killing them while keeping everything else alive was.

Thousands of compounds were formulated and tested in a war that was part ingenuity, part perseverance. Science has moved on since, but a similarly dogged spirit may be required.

“There is always a way to solve problems,” said McClinchley.

“It will take work, discipline, and resources, but failure can’t be an option. The cost to the Great Lakes is just too great.”

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