The Manitoba government says its experiment to eradicate a zebra mussel invasion in Lake Winnipeg appears to be successful, at least in one of its harbours.

Officials say Winnipeg Beach will be reopened after it was closed two weeks ago.

The harbour was one of four that was sealed off with a silt curtain and pumped through with liquid potash until it reached a lethal concentration for the mussels.

zebra mussels

Manitoba government officials announced Monday that an experimental liquid potash treatment has killed zebra mussels at the harbour in Winnipeg Beach. (CBC)

Rob Nedotiafko, who co-ordinated the treatment, says test mussels in a nearby secure cage have all died.

"The gated curtain at the mouth of the harbour was removed, officially signifying the end of the treatment process," Nedotiafko told reporters Monday afternoon.

"It was determined late yesterday that all test zebra mussels in the harbour, through mortality testing, were confirmed dead."

Because the mussels in the cage died, officials are assuming the ones not in the cage are dead as well.

Nedotiafko said so far, the signs are promising for the harbours at Gimli, Balsam Bay and Arnes. The potash treatment began at Balsam Bay on May 24 and at Gimli Harbour on Saturday, while a curtain is currently being installed at Arnes.

The province says the liquid potash treatment in open water, in a lake environment, is the first of its kind.

Conservation Minister Gord Mackintosh has said the province had to take action in the hope of keeping the mussels out of Lake Winnipeg.

He says the province is focusing on a long-term strategy to ensure the mussels don't take hold.

The mussels, which were found for the first time in Manitoba last October, reproduce quickly and can disrupt the food chain, clog water pipes and create algae.

With files from The Canadian Press