Every September and October, hundreds of boats are taken out of Lake Winnipeg at Gimli Harbour.

The difference this year is what boat owners are finding stuck to hulls and propellers.

Dean Thorkelsson is the manager of Lake Agassi Marine. He said zebra mussels have grown in numbers in Lake Winnipeg like they've never seen before.

Every boat taken off the lake is now driven to an offsite gravel pad to be washed thoroughly with hot water to make sure the invasive species doesn't make it back into any other body of water.

Gord Mackintosh, the acting Minister of Conservation, said the province is working on new zebra mussel laws that will be the toughest in the country.

"We have a large infestation in Manitoba's largest lake, now we have 100,000 more to protect," said Mackintosh.

Mackintosh reminds boat owners of the province's slogan and campaign, 'don't move a mussel.'

The aquatic invasive species has popped up in Lake Winnipeg at Victoria Beach, Grand Beach and the Winnipeg Beach area on beaches, boats and docks. In the Red River, they’ve been found at St. Andrews Lock and Dam.

Possessing and transporting zebra mussels is illegal in Manitoba.