The population of sea lamprey, an invasive fish species in Michigan, is declining in four of the five Great Lakes.
Research from the Great Lakes Fishery Commission (GLFC) showed that sea lamprey populations have decreased by 25% in 2026 in every Great Lake except for Lake Erie.
Sea lampreys are parasitic fish that are dangerous to native fish in the Great Lakes. They can eat up to 40 pounds of fish throughout their lifespan. This makes fish native to the Great Lakes like lake trout struggle to keep up with the predators.
The invasive species also reproduces at a very high rate. Female sea lampreys lay nearly 100,000 eggs, which makes it difficult to keep population rates moving in the right direction.
Director of Policy and Legislative Affairs at GLFC Greg McClinchey said that monitoring the sea lamprey population is crucial to keep native fish species thriving.
“If the sea lamprey are allowed to continue without control, they have the capacity to eliminate fish in the Great Lakes,” he said. “Keeping them in check is absolutely critical.”
The commission and its monitoring are a binational effort. Since sea lamprey are impacting the Great Lakes in both the United States and Canada, the two countries are working together to measure the sea lamprey population.
The overall goal of the commission is to completely eliminate sea lamprey in the Great Lakes. This would protect native species and ensure that the health of the lakes is prioritized.
However, McClinchey said that there is still a long way to go to make that goal possible.
“The state of technology right now and the tactics and techniques used for control probably don’t put the elimination of the species in the Great Lakes on the table,” he said.
Despite the current limitations, McClinchey said that the progress they are seeing in the sea lamprey population is very encouraging.
The commission said that they will continue to monitor and control the sea lamprey population to lessen their destruction.
