Decreased Sea Lamprey Abundances in Great Lakes

The Great Lakes Fishery Commission (GLFC) reports an encouraging trend as adult sea lamprey continue to show decreased abundances in most of the Great Lakes, including Lake Erie and Lake Ontario from 2024 to 2025. Population estimates were established through mark-recapture studies conducted on index tributaries each year during the spring and summer. Reports show the 3-year average of adult sea lamprey abundance decreased in 2025 and is below the target for Lake Erie, while in Lake Ontario abundance decreased but remains above the target.

Sea lamprey act as predators, with each individual capable of killing up to 40 pounds of fish over their life. Successful control of sea lamprey is crucial for maintaining popular sport fisheries in the New York waters of Lake Erie and Lake Ontario.

For more details, review the 2025 Status of Sea Lamprey Control on the GLFC site.

Sea lamprey are parasitic invasive species that injure fish such a lake trout, lake whitefish, and ciscoes, by using their tooth-filled suction cup mouth to latch onto and feed off the blood and bodily fluids of their prey. (Photo courtesy of A. Miehls, GLFC)