The number of invasive sea lamprey in the Great Lakes has gone down after regular control and treatment efforts resumed. According to a report from the Great Lakes Fishery Commission, surveys of the lamprey show their numbers have returned to pre-pandemic levels.
During the COVID-19 pandemic, the amount of sea lamprey in the Great Lakes surged because treatments were limited.
Greg McClinchey is the Director of Policy and Legislative Affairs for the Great Lakes Fishery Commission. He said one of their primary responsibilities is to control invasive sea lamprey in the Great Lakes. The Commission itself was created in the 1950s to control the lamprey and sustain the Great Lakes’ fishing industry.
“They have the capacity to basically eliminate fishing in the Great Lakes if they're not managed properly,” McClinchey said. He said they weren’t able to manage the population during the pandemic because borders were closed and they had to practice social distancing, among other restrictions.
Sea lamprey are an invasive species native to the Atlantic Ocean that feed on the blood and bodily fluids of fish. According to McClinchey, the problem is that every sea lamprey can eat up to 40 pounds of fish, while every female can have around 100,000 eggs. “That equals really bad, really fast,” he said.
“They’re one of 186 invasives that are in the Great Lakes system, and they present a pretty serious threat,” McClinchey said. “So we try and control their numbers, otherwise they would historically have been able to outcompete humans for fish harvest in the Great Lakes. If left unchecked, they will simply eat us out of house and home.”
McClinchey said they use a compound the lamprey haven’t learned to metabolize called PFM, or lampricide, and put it into streams. It kills juvenile lamprey before they can begin feeding without harming anything else in the stream. McClinchey said they also use bubble and electric barriers to restrict the movement of sea lamprey.
The Great Lakes Fishery Commission works in partnership with Fisheries and Oceans Canada, the U.S. Fish and Wildlife Service, and the U.S. Geological Survey to conduct and organize control efforts.
McClinchey said their goal is for the numbers to continue on their downward trajectory. He said controlling the population of sea lamprey will continue to sustain the fish and fishing industry of the Great Lakes, supporting the economy.
McClinchey said the results of the annual survey reflect a positive trend. The report indicated that the 3 year average numbers decreased in all the Great Lakes except for Lake Superior.
