Invasive “vampire fish” or sea lamprey populations are spiking in the Great Lakes. According to the Wall Street Journal, the invasive parasites are “scaring” anglers and tourists in the region. The lampreys leech blood from lake trout and other sport fish, hence their nickname. Fisheries managers say the species threatens the Great Lakes’ $7 billion fishing industry.

“We’re very happy that they’re not cute like bunnies because it would be much harder to convince people that we need to rid the Great Lakes of them,” Greg McClinchey, legislative affairs and policy director for the Great Lakes Fishery Commission, told the WSJ. “They are unquestionably the stuff of nightmares.”

According to the NOAA, the sea lamprey may have been “America’s first destructive invasive species.” The parasitic fish is native to the Atlantic Ocean, but the species spread into the Great Lakes in the 1830s via the Welland Canal — and quickly started feeding on the lakes’ native fishes. “Within a decade, they had gained access to all five Great Lakes, where they quickly set to work predating on the lakes’ commercially important fishes, including trout, whitefish, perch, and sturgeon,” explains the NOAA. “Within a century, the trout fishery had collapsed, largely due to the lamprey’s unchecked proliferation.”

In recent decades, though, the Great Lakes Fishery Commission has been fairly successful in knocking down sea lamprey numbers. Yearly mitigation efforts involve in-stream control using “lampricide”—a pesticide that impacts the species. But in 2020 and 2021, those efforts were largely hampered by restrictions resulting from the COVID-19 Pandemic, leading to the recent rise in sea lamprey numbers. The mitigation efforts typically have a two-year lag in results, and fisheries managers are hoping this year’s population rise will prove fleeting.

Read Next: Invasive Snakehead Caught in Missouri for Second Time

“We’ve been hitting the lamprey hard in 2022 and 2023, so we’re hoping the COVID spike was a blip,” fisheries specialist Jeff Gunderson told Fox News. ” Sea lampreys are slimy, opportunistic, resilient beasts that will destroy tens of millions of pounds of Great Lakes fish given the chance. Control is successful and does not give sea lampreys that chance. But, like a successful invader, sea lampreys are here to stay, unfortunately. But we can control them.”