The mussels, which have already caused damage in the Great Lakes and spread in 2010 to North Dakota, were recently discovered on fishing boats and a dock in two communities along Lake Winnipeg — Gimli and Winnipeg Beach.
"We're not quite sure what the exact scenario will be for Lake Winnipeg, but we do know from other jurisdictions where they have zebra mussels that certainly there is an effect on the fish community, on the water quality," Laureen Janusz, a fisheries biologist with Manitoba Conservation and Water Stewardship, said Thursday.
The mussels multiply rapidly, gobble up plankton and help create algae. Zebra mussels also attach themselves to solid objects, clogging municipal and residential water supply pipes and more. They spread by attaching themselves to boats.
"They can clog a pipe. They can clog the intakes on your boat," Janusz said.
Manitoba has been trying to stop the arrival of zebra mussles for years by urging boat owners to inspect and clean their vessels before bringing them from other jurisdictions. The province is now asking boat owners along the lake, the Red River and the Nelson River to do the same before transporting their vessels to other waterways.
Conservation and Water Stewardship will be inspecting boats in the area until Lake Winnipeg freezes. The province also says it will deploy mobile decontamination units as needed.