The busiest harbour on Lake Winnipeg could be reopened by the weekend if a bid to use liquid potash to kill zebra mussels is successful.
Rob Nedotiafko, who is co-ordinating the treatment for Manitoba Conservation, said today after 10 days of treatment at Gimli the zebra mussels samples were "showing signs of significant distress."
The Gimli harbour was sealed with a silt curtain for the pumping of liquid potash (potassium) beginning May 31.
Nedotiafko said officials should know later this week if the treatment worked. The same process has been used successfully at Winnipeg Beach and at Balsam Bay. Treatment at Arnes started last Thursday.
The plan involves charging the sealed-off area until a lethal concentration of potassium is reached for the mussels. That level must be maintained for several days until all zebra mussel samples are dead.
Nedotiafko said the only blip in the treatment plan at Gimli was when the curtain was ripped in a wind event last Sunday. It was replaced and the harbour was recharged with potash.
The potash plan will cost $600,000, but the province has said it could save millions down the road if the mussels are stopped from spreading to other areas of the lake.
To lessen the impact on commercial fishers, the province installed a gated silt curtain to keep the liquid potash in the harbour, which can be opened to allow fishers in and out of the harbour.
The gated curtain also allows the coast guard and search and rescue boats out onto the lake. The potash is not harmful to the lake’s ecosystem.
The mussels were first found last fall on the hull of a private boat and a dock at Winnipeg Beach and on some fishing boats dry-docked at Gimli. It’s not know how they entered or for how long they’d been in the lake.