Sea lamprey populations are on the decline across the Great Lakes.
According to the Great Lakes Fishery Commission's Status of Sea Lamprey Control report, the number of adult lampreys captured in 2025 in Lakes Huron, Erie, Michigan, and Ontario was below the three-year average.
Each of the five lakes saw an overall decrease in 2025, but Lake Superior's overall population remains above the three-year average.
The decline in lampreys is necessary because the invasive species attaches to fish and feeds on their blood. The parasitic fish has become a significant threat to lake trout, whitefish, and other native species, as it can kill up to 40 pounds of fish.
“The Great Lakes mean a great deal to the millions of people living, working, and recreating in the basin. This $5.1 billion industry will crash if sea lamprey populations get out of control again. No one wants to have a repeat of the early days when it was hard to find a fish without a sea lamprey wound," said Ethan Baker, chair of the Great Lakes Fishery Commission.
Earlier this month, the commission announced it would implement its Supplemental Sea Lamprey Control Initiative over the next five years to further reduce the invasive species' population.
The initiative will employ non-traditional methods such as electrical barriers, traps, scent cues, and sterile male releases.
