New sea lamprey barrier

protects Lake Ontario fishery

A new sea lamprey barrier and trap in New York’s Orwell Brook will protect fish in Lake Ontario and reduce the cost of controlling the deadly invader’s population.


The sea lamprey is one of the most destructive invasive species in the Great Lakes. The eel-like fish, which cling to trout, salmon and whitefish and suck out their blood and other bodily fluids, decimated Great Lakes fish populations in the 1930s and ’40s. The Great Lakes Fishery Commission has been controlling sea lamprey populations since the 1950s, primarily by treating streams with chemical lampricides. In June, a new weapon was added to the sea lamprey control program arsenal: a sea lamprey barrier and trap in New York’s Orwell Brook. The barrier will reduce lampricide treatments that have been conducted on the brook since 2007. Orwell and Pekin brooks, which flow into Lake Ontario’s Salmon River, produce tens of thousands of sea lamprey larvae annually. Those lamprey eventually move into Lake Ontario to feast on trout, whitefish and salmon before returning to the stream to spawn. A single female lamprey can produce more than 100,000 eggs, and each adult lamprey can kill up to 40 pounds of fish annually. The new barrier at Orwell Brook is an adjustable crest, low-head barrier that blocks sea lamprey from spawning in the stream while allowing steelhead and Atlantic salmon to bypass the structure and migrate further upstream. The barrier also captures sea lamprey in a built-in trap. Ending the use of chemical lampricides in Orwell Brook, above the new barrier, will save hundreds of thousands of dollars in treatment costs.

Resource Challenges Addressed

  • Loss of sport and commercial fish
  • Invasive species


Sea lamprey in a trap

Sea lamprey hurt and kill native fish and need to be controlled to support a healthy ecosystem. Credit: Mara Koenig U.S. Fish and Wildlife Service.

Results and Accomplishments

The new barrier will reduce sea lamprey populations in Orwell Brook and Lake Ontario, which will benefit the lake’s trout and salmon fisheries, and reduce the cost of controlling the sea lamprey population.