Invasive plant clogging Quebec lakes

Residents of Granby, Que., say they are losing the use of popular Lake Boivin because of a new invasive species of plant known as Eurasian milfoil.

In recent years, several waterfronts in Quebec have been shut down because of the presence of blue-green algae. Now environmentalists say Eurasian milfoil is turning some lakes into swamps.

"All of our pedal boats have been breaking because there is so much aquatic vegetation," said Marc-André Guertin, Granby's environment co-ordinator.

Like blue-green algae, Guertin said, Eurasian milfoil feeds on phosphorus, which is produced by various human activities such as agriculture.

Because the species is not indigenous to the region, "There are no natural predators to either feed on it, or any bacteria or viruses that control its growth. So it's definitely taking over large parts of the lake," Guertin said. 

Guertin said the town will map the growth of the plant to see how far it has spread. It will also adopt a green plan to limit the amount of phosphorous that seeps into the lake.

Lake Memphramagog, about 50 kilometres southeast of Granby, has also been plagued by Eurasian milfoil.

Thirty years ago, there was hardly any aquatic vegetation in the lake, according to Giselle Lacasse-Benoît, president of Memphramagog Conservation.

 "And now it's all covered. To swim, we have to cut a few of them to get on the dock and swim a bit," she said.