Fisheries and Oceans Canada, in partnership with the Great Lakes Fishery Commission, plans to conduct a sea lamprey control treatment on Salmon River (Lewis/Oswego County), Grindstone Creek (Oswego County), Little Sandy Creek (Oswego County), Black River (Jefferson County). Applications are currently scheduled to be conducted from May to June, 2026 (Salmon River, Grindstone Creek, and Little Sandy Creek), and August to September 2026 (Black River, Little River, and Fish Creek), in accordance with State of New York permits. Application dates are tentative and may be changed based upon local weather or stream conditions near the time of treatment. For up-to-date information, see the treatment schedule link at the end of this message.

Sea lampreys are invasive parasitic fish native to the Atlantic Ocean that entered the Great Lakes in the early 1900s through shipping canals. They attach to fish using a suction-cup mouth lined with teeth, feed on the blood and bodily fluids, and often kills their hosts. A single sea lamprey can destroy up to 40 pounds of fish during its 12-18 month parasitic phase. Because of the sea lampreys’ high reproductive potential—a single female can lay tens of thousands of eggs—uncontrolled populations can cause severe and lasting damage to valuable Great Lakes fisheries, including those in Lake Ontario.

During treatment, trained and certified crews will apply lampricides to target sea lamprey larvae living burrowed in the streambed for up to 12 hours. This method of control, which has been used since 1958 has undergone extensive review by the U.S. Environmental Protection Agency and Health Canada and is considered safe for people and the environment when applied at the approved concentrations. Treatments are carefully planned and continuously monitored, including testing lampricide concentration and water chemistry at various sites before and during application.

During this period, you may notice sea lamprey control field crews working along the stream or see temporary red or green coloration in the water. The colors come from non-toxic dyes used to monitor stream water flow so that precise concentrations of lampricides can be achieved during treatment. The lampricide treatment itself will tint the water slightly yellow, will flush from the system once the treatment ends, and dilutes and degrades to non-detectable levels shortly after the treatment ends.

As a precaution, agricultural irrigation drawn from the treated sections of the stream should be suspended at the start of the treatment until 24 hours after the it concludes, and anyone holding bait fish or other aquatic organisms in stream water should use an alternate water source during that time.

This work is part of a long-standing Great Lakes conservation program that has played a critical role in maintaining a healthy $5.1 billion fishery—both commercial and recreational—and the local economies dependent on them.

As a source of local information, we ask that you share this information with your local constituents through whatever means you have available, including social media. If you would like us to share this information on social media, please contact Jill Wingfield below with the names of local groups or pages who would benefit from this information.

For more information or if you have any questions, please contact the following:

For landowner-related questions: contact the Sea Lamprey Control Center main desk at 1-705-941-3000 or 1-866-290-3731 and they will pass your message along to the control supervisor.

For media-related questions: Jill Wingfield at 734-262-7717 or This email address is being protected from spambots. You need JavaScript enabled to view it..

Other Useful Resources

For more information on sea lamprey and control efforts: https://www.glfc.org/sea-lamprey.php

Information on lampricide applications: https://www.glfc.org/pubs/factsheets/FACT%204A_HR.pdf

Documentary on sea lamprey in the Great Lakes and the control efforts: https://www.thefishthief.com/

Lamprey Treatment Schedule (most up-to-date information): https://www.glfc.org/treatment-schedule.php