SENECA LAKE – A program to combat the parasitic sea lamprey is scheduled to begin this week on Seneca Lake tributaries including the Keuka Outlet from Cascade Mills downstream.

DEC officials say treatment can reduce mortality rates for fish targeted by sea lamprey, especially lake trout, rainbow trout, brown trout, and landlocked salmon. 

Typically, immature sea lamprey live in streams for three to four years before they become parasitic, descending into the lake to prey on other fish, like trout and salmon. DEC will apply a lampricide, called TFM (3-trifluoromethyl-4-nitrophenol) to the streams in a continuous, metered manner over 12 hours to kill the immature, larval form of the sea lamprey. TFM is a selective pesticide used extensively for sea lamprey control in the Great Lakes for decades and in Seneca Lake tributaries since 1982. The dosage levels of TFM that are lethal to larval sea lampreys can be harmlessly processed by most other aquatic organisms. For details about the treatment, visit and search for Sea Lamprey Seneca Lake.