Invasive Fish-Killer Population Grew in Great Lakes During COVID

The Great Lakes are home to plenty of wildlife, but not all of the creatures beneath the Lakes' surfaces are beneficial to the ecosystem.

The Detroit Free Press recently published an article detailing the dangers of an invasive species that is terrorizing fish in the Great Lakes, and it's only getting worse.

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Lamprey Terrorize Fish Populations in the Great Lakes

You may have heard of "Vampire Fish". Fishers in the Great Lakes have been unfortunate enough to see them latched onto their catch. These sci-fi-esque creatures are called lampreys, and despite best-laid plans, lampreys are continuously problematic for fishers and fish alike.

As the Detroit Free Press piece details, the COVID-19 pandemic disrupted plans implemented by both the United States and Canadian governments. Lake Ontario suffered the worst as the only Great Lake where control efforts were halted completely in 2020. In Lake Ontario, the lamprey population grew tenfold.

Lampreys are eel-like creatures with mouths suited for a horror film. These parasitic fish latch onto fish with their suction cup mouth while digging their teeth into the flesh, leeching the host's body fluids. As the Great Lakes Fishery Commission details, unlike the lamprey native to the Atlantic Ocean, lamprey in the Great Lakes haven't evolved in a manner that prevents them from being lethal to their hosts.

Lamprey dismantled the Great Lakes fishery efforts in the late 1940s, when the parasite's population exploded in the Great Lakes. Where once the Great Lakes produced 15 million pounds of lake trout in the upper Great Lakes per year dropped to roughly 300,000 pounds annually. By the mid-1990s, when lamprey populations peaked at about 2.5 million, the vampire fish killed 100 million pounds of fish in the Great Lakes per year.

Because of the recent findings from comparable data from pre-, post- and during the COVID-19 pandemic disruptions, the Great Lakes Fishery Commission is continuing its effort to drown out the lamprey population using lampricides, or chemicals that can kill lamprey larvae without harming other plants or animals in the environment.