Harbours to close in war on zebra mussels

Officials in Manitoba are hoping that they can stop the spread of zebra mussels in Lake Winnipeg by loading liquid potash into four harbours.

The invasive mussels are already present in the Great Lakes and the St. Lawrence River, but were only spotted in Lake Winnipeg in 2013. They have a variety of harmful environmental impacts, including colonizing intake structures in power plants and water treatment plants.

Efforts to monitor boats and vessels entering Lake Winnipeg have failed to keep the pests out, so now ASI Consulting Group of Ontario is being hired to administer Potassium Chloride Aqueous Solution 20 per cent in the harbours of Gimli, Winnipeg Beach, Balsam Bay, and Armes.

As a result the harbours would need to be closed to boats from mid-May to mid-June.

Local fishermen are upset because this period is crucial for their business.

Opinions on the efficacy of the potash to contain the mussels differ. As quoted in a CBC news report, one University of Winnipeg biologist, Eva Pip, believes the $500-million measure is just a stopgap and that since the mussels have been found on both sides of the lake they can’t be stopped.

Manitoba Conservation Minister Gord Mackintosh told the CBC that the liquid potash treatment was effective in eradicating the mussels in a study done in Virginia. However, that study was done in a small pond, not a dynamic basin like Lake Winnipeg.

Professor Hugh MacIsaac, a professor at the University of Windsor’s Great Lakes Institute and director of the Canadian Aquatic Invasive Species Network, said in the CBC report that the potash treatment won’t kill other mussels or fish and that it’s safer than alternatives.

Some aquatic areas in the harbours will be protected by a silt curtain when the potash is being dispensed.

To read the CBC report of May 1, click here.