At the June meet-and-greet organised by the GLFC, half a dozen sea lampreys posed for the cameras at the Capitol. One of them even sucked on the palm of Representative Bill Huizenga, as per a CNN report. Among the few things the entire Congress agrees on, this is one: the invasive sea lampreys must go.For the American coasts that thrive on their seafood population, the invasive species, also known as ‘vampire’ fishes or the ‘vampire’ of the Great Lakes, has had a devastating impact on the lakes’ trout, salmon and whitefish population. And thus, have inspired what scientists often call the ‘forbidden experiment’.
Arrival of sea lampreys
Once the Welland Canal was modified by the mid-1900s, allowing ships to circumnavigate Niagara Falls, the sea lamprey population boomed
Sea Lampreys were once native to the Atlantic Ocean. The first ones arrived in Lake Ontario in the 1800s, making their way from the Atlantic Ocean, through the Hudson River, following the Erie Canal. They remained in Lake Ontario for over a century because Niagara Falls barred them from moving any further.Once the Welland Canal was modified by the mid-1900s, allowing ships to circumnavigate Niagara Falls, the sea lamprey population boomed. They had finally gained access to the upper Great Lakes. Suddenly, lampreys had more space, found more food and colonised more spawning grounds. The invasion had begun.A sea lamprey has no jaw, no proper teeth and no bones. Yet this predator can attack like a suction cup to a fish 100 times its size, using its tongue to bore a hole into its side, liquefy its tissues and feed on it. Sea lampreys are quite fertile (like other invasive species) and have a unique life cycle, for a fish. One lamprey consumes around 40 pounds of fish in 12-18 months and a female can lay 40,000-67,000 eggs, and they do it in almost every stream and river that drains into the Great Lakes. Those eggs hatch into larvae, called ammocoetes, which are eyeless, worm-like creatures that burrow in the sediment, making it impossible for predators to find them. The ammocoetes live like this for many years, feeding on algae and decomposing matter, until they are big enough to transform into the sucking predator.A single lamprey can kill up to 20 kilograms of fish in just two years. On this fishy, bloody diet, a young lamprey weighing five grams will grow 40 to 50 times larger by the time it becomes an adult. And there are thousands of these vampire fish in the Great Lakes.
Loss of native fish
Sea lamprey feeding on a trout; fish with a wound caused by a lamprey
When the lamprey invaded the Great Lakes, lake trout, their preferred food and once a top predator fish, began dying out. By the mid-1960s, the lake trout harvest in the Great Lakes had declined to less than 200,000 kilograms per year from eight million kilograms per year in the 1920s.Alewives, small fish that lake trout ate, were no longer preyed upon. They became so abundant that every year there were massive die-offs in the lakes, and millions of dead fish would wash out on the beaches.
The forbidden experiment
In 1954, Canada and the United States established a partnership to tackle the sea lamprey problem, and the Great Lakes Fishery Commission (GLFC) came to be. A moonshot project to control the population succeeded in 1957, when a chemical compound called TFM (3-trifluoromethyl-4-nitrophenol) was developed, which kills lamprey larvae, without harming most 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.Lampricide works because the larvae are unable to metabolise 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.Almost seven decades after the moonshot, all the effort was nearly undone. During lockdown in 2020 and 2021, the staff had to maintain social distance, which led to fewer treatments taking place and the commission was unable to implement its full control program. The lamprey population “skyrocketed” by 300% in some areas, said Greg McClinchley, director of policy and legislative affairs at the Great Lakes Fishery Commission (GLFC). “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).”Around 9 million sea lampreys need to be killed every year just to prevent a population explosion. If left uncontrolled, the estimated lampreys could collapse the Great Lakes’ fish stocks and with it, a multibillion-dollar fishing industry, in just five years, says the GLFC.
More moonshots needed?
Other species like the quagga mussel and zebra mussel are now plaguing the lakes.
Sea lampreys are only one of the 186 invasive species among the 3,000 species in the Great Lakes. Other species like the quagga mussel and zebra mussel are now plaguing the lakes. 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. 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 theorised that poisoned gobies become paralysed and easy prey for birds, which then die from the toxin. There is currently no way to safely eliminate them from the Great Lakes.“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,” said Vito Figliomeni, executive director of the Ontario Commercial Fisheries’ Association.As per a CNN report, 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.
