Status of Sea Lamprey in Lake Erie and Lake Ontario

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Status of Sea Lamprey in Lake Erie and Lake Ontario Sea Lamprey are a parasitic invasive species in the Great Lakes that attack and kill trout, salmon, and other desirable sportfish. A single sea lamprey can consume over 40 pounds of fish in its lifetime and their presence threatens sustainable fisheries. The Great Lakes Fishery Commission (GLFC) is charged with conducting sea lamprey control in all five Great Lakes. One way that the GLFC monitors the succuss of the control program is by annually estimating the number of adult sea lamprey in each lake. The adult sea lamprey index in Lake Erie was higher than the management target for many years but has been below, or near, the target for the last five years. In 2024, the adult index number was below target but the 3-year average remained slightly above target (Figure 1). In Lake Ontario, the adult sea lamprey index was below the management target from 2015-2021, but the sea lamprey abundance increased dramatically in 2022-2023 due in part to missed sea lamprey control treatments during the COVID-19 pandemic. The adult index value declined in 2024 but remained above the target (Figure 1). Sea lamprey control treatments resumed in 2022 and the adult index should continue to decline in the coming years.    DEC Fisheries Works for You!