People had to watch their step to avoid being cut when sharp-edged zebra mussels showed up recently at one of the best-known beaches in Canada.

Zebra mussels lined the shore of Grand Beach on Lake Winnipeg last weekend.

The province confirmed the small, rapidly multipying creatures were spotted at Grand Beach last summer as well, but couldn't say if the problem is getting worse.

Candace Parks is the aquatic invasive species specialist for the department of sustainable development.

She says it's too late to eradicate them from Lake Winnipeg, but we can slow their spread to other bodies of water.

"Is it time to give up? No. It is time for people to roll up their sleeves and go 'I do not want zebra mussels at my lake, I don't want zebra mussels in my river. I'm going to do what I need to do. Quick, simple steps: clean, drain, dry, and I can make sure I am not the one spreading zebra mussels to a new area.'"

Parks says at this point three of Manitoba's 100,000 water bodies have zebra mussels. She says to stop their spread, people need to clean, drain, and dry their watercraft and equipment whenever they leave a body of water. She also says it's the law to do so before entering another body of water.

According to the province, zebra mussels are a significant environmental and economic concern to Manitoba. They aggressively invade new areas, colonize almost any hard surface, negatively impact power and water-based infrastructure, and threaten native fish and wildlife.