The Eurasian Ruffe, a small fish from northern Europe and Asia, is causing problems in Ontario and nearby regions. Likely introduced to North America in ship ballast water in the 1980s, it is now banned in Ontario and some U.S. states to prevent its spread.
Eurasian Ruffe thrives in various environments, including fresh and brackish waters. They have been found near Thunder Bay and are spreading along Lake Erie and Sault Ste. Marie. In the U.S., they are present along the shores of Lakes Superior, Michigan, and Huron.
These fish impact local ecosystems by competing with native fish like Yellow Perch for food and habitat. They grow quickly, mature in 2-3 years, and live about 7 years, with few predators due to their hard dorsal spines. This rapid growth and reproduction can lead to a decline in native species and could eventually spread to all the Great Lakes.
The public can help by learning to identify Eurasian Ruffe and avoiding its spread. Don’t release live fish into lakes or rivers; empty bait buckets on dry land. Report sightings by calling 1-800-563-7711 or using the ‘Invasive Species in Ontario’ project on iNaturalist.org
Written by Jeremy Hall