Invasive sea lamprey made an unwelcome comeback during pandemic

Officials say that one of the effects of the pandemic has been a surge in the growth of the invasive sea lamprey in the Great Lakes.

Researchers on both sides of the border have recently confirmed a bounce-back for one of the Great Lakes’ biggest burdens: the invasive sea lamprey.

Reduced control efforts during the pandemic are now being felt, with a rise in the number of the notorious ‘vampire fish’ across the Great Lakes.

“They’re a coiled menace,” said Greg McClinchey of the Great Lakes Fishery Commission.

“This proves that the moment you take your foot off of them, they bounce back.”

The population of sea lamprey increased tenfold in the Great Lakes during the COVID-19 pandemic, along with the number of lamprey wounds found on fish such as salmon.

The cross-border organizations that reduce those populations were handcuffed by travel restrictions and social distancing mandates.

“Our program at the Great Lakes Fishery Commission is border blind,” McClinchey said.

“It’s reliant on partnerships and it’s very hands-on. It requires, you know, boots in the water kind of thing. And then in 2020, we had to reduce that by about 75 per cent, and in 2021 by about 25 per cent.”

The complex ways of measuring sea lamprey populations take two or three years to get an accurate read, which is why officials are just now seeing the population drop.

To cull what are sometimes referred to as ‘vampire fish,’ experts treat lamprey-infested streams with a chemical that targets the parasite, while avoiding harm to other fish.

“The Great Lakes Fishery Commission take about eight and a half or nine million lamprey out of the system each and every year,” McClinchey said.

“Those lamprey would eat about 12 million pounds of fish at a direct cost of about $270 million worth of landed value lost.”

Officials said sea lampreys could wipe out fishing in the Great Lakes in three to five years if left untouched.

While the commission’s efforts are just beginning for the season, McClinchey adds that every day, people play a large role in the suppression of this invasive species, and he urges people to learn more about how they can make a difference.