Bulletins

Larval populations of sea lampreys — a non-endemic, parasitic species that feeds on native fish populations — have been detected in sections of the Rouge River watershed in Rouge National Urban Park. To control the population, between April 28 and May 2, 2024, trained staff from Fisheries and Oceans Canada will treat two sections of river within the park with lampricide, closely monitoring water quality and concentration to ensure safety.

• One section will be on the Little Rouge Creek near Highway 7.
• The other will be the Rouge River near the intersection of 9th Line and Steeles Avenue East.

Lampricide dissipates naturally, posing minimal risk to humans and aquatic organisms.

During treatment, visitors may notice a temporary change in water colour to orange-red or yellowish-green, which typically resolves within 12 hours. As a precaution, it is advised that visitors avoid unnecessary exposure to the water while treatment is applied.

The Great Lakes Fishery Commission has been working to control invasive sea lamprey populations in the Great Lakes for decades. Proactive measures, like the use of lampricide treatment applied by Fisheries and Oceans Canada, help maintain a healthy balance in the ecosystem and protect native fish populations. Affected streams and tributaries of the Great Lakes are treated with lampricide every 3 to 5 years and specifically target sea lamprey larvae, minimizing harm to other aquatic life.

Learn more about lampricide application and the ongoing efforts to protect the Great Lakes ecosystem.

For more information about Fisheries and Oceans Canada’s work regarding sea lamprey control, please visit the department's website.