Any time she sees a boat dragging strands of weeds from Ramsey Lake, it worries Margaret McLaughlin, chair of the Greater Sudbury Watershed Alliance.

"If [the boats] go from one lake that has an invasive species, then they have the potential of taking it to another lake," she said.

A few attempts have been made to stop the spread of eurasian watermilfoil, including the use of weevils. (CBC) Unwanted plants and insects get caught in motors and boat trailers and then hitch a ride. The next time the boat is launched in a different lake, those species are transported to other water bodies.

"Because they have no predators, they can just start growing," she said.

Sudbury currently has two invasive species that are making their way through the region's lakes.

Spiny water flea - the long spiny tail is a defence against small fish. (Jake Walsh) McLaughlin is especially concerned with the spread of eurasian watermilfoil. The non-native weed chokes out other plants and makes the lake unswimmable.

"Simon Lake has eurasian watermilfoil so bad it's like a forest growing in the water. It's a mat on the surface, You can't swim in it. You can't boat in it. You almost can walk on the weeds."

Margaret McLaughlin, chair of the Greater Sudbury Watershed Alliance, says that the prospect of invasive species spreading to Sudbury's lakes worries her. (Marina Von Stackelberg/CBC) So far, it has spread to more than a dozen lakes in Sudbury.

"It's very easy to transplant. You just break off a little piece and it will float down and establish itself somewhere else. It's very easy to infect another lake."

A new concern is also the spiny water flea, an insect that can get caught on boats and fishing line. It's harmless to humans and pets, but destroys the food source of young fish. Last year it spread to a second lake in Sudbury.

Wash your boats

McLaughlin says boats are a big reason why these invasive species are spreading, and the solution is simple

"Inspect your boat when you come out of the lake, clean it, drain all the pumps, clean your trailer, before they go into another lake," she said.

Stephen Monet, manager of environmental planning at the city, says that Sudbury is lucky to only have two invasive species. (Marina von Stackelberg/CBC) You can also kill the plants by leaving your boat out in the sun for five days.

Sudbury lucky, but at risk

Sudbury has been lucky so far, according to Stephen Monet, manager of environmental planning at the city.

"There are many other invasive species in Ontario. We're very fortunate that we only have two species in Greater Sudbury."

Still, Monet said new unwanted plants and insects could make it up here.

"All of these invasive species and many others have the potential to arrive here,"

"You could be putting your boat into in eastern Ontario, or the muskokas for the weekend, and bringing [the invasive species] up to Greater Sudbury within a few days," he said.

All it would take is one dirty boat.