For more than a century, an invasive species has been literally sucking the life out of the Great Lakes: sea lampreys. Throughout its life cycle, one sea lamprey can kill up to 40 pounds of Great Lakes fish with its suction-cup mouth, hundreds of teeth and drill-like tongue.
“When a lamprey attaches to a fish, the tongue will flick out, drill through the scales and skin of the fish and feed off the fish’s blood and body fluids,” says Mark Gaden, executive secretary of the Great Lakes Fishery Commission.
Sea lampreys entered the Great Lakes from the Atlantic Ocean, following the Erie Canal’s completion in 1825. By the 1930s, they had nearly destroyed fisheries already under threat from pollution and overfishing at an industrial scale.
“When you already have a stressed fishery, adding that pressure was more than the fishery could bear,” Gaden says.
The Great Lakes Fishery Commission’s Sea Lamprey Control Program brought the fisheries back from the brink of collapse. Since 1958, the program has kept the sea lamprey population under control, with the lamprey population falling by 90% since it began.
Earlier this year, that progress came under threat from budget cuts, firings and a hiring freeze from the Trump administration.
“We lost probably about 350 years of combined experience by people who were kind of late-career and took the offers that the administration offered,” says Mark Gaden, executive secretary of the Great Lakes Fishery Commission.
Many of those cuts have since been reversed, and the program has secured full funding and staffing for 2026. But its future remains uncertain.
“I'm cautiously optimistic, given the funding that's been provided, that we'll continue to see that political support and be able to move forward in 2026 fully staffed,” Gaden says. “But there's still a lot of work to do and a lot of unknowns.”
Gaden's work is featured in a recent piece by Katie Thornton for The New Yorker, on the workers who manage lamprey populations in the Great Lakes. Thornton and Gaden both joined Lake Effect’s to talk about the importance of this work.
“So often we hear about federal workers or federal programs, and if you haven't seen it firsthand, you don't necessarily know what it takes to do this work,” says Thornton.
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