Provincial fisheries inspectors are investigating the escape of possibly hundreds of market-ready salmon from an aquaculture pen at the mouth of Shelburne Harbour.

Employees at Cooke Aquaculture noticed a breach in one of the company's enclosures last Wednesday and notified the province. They discovered some fish had escaped two days later, said Krista Higdon, a spokeswoman for the Nova Scotia Department of Fisheries and Aquaculture.

Cooke spokeswoman Nell Halse said it appeared wind and waves associated with recent winter storms knocked over one of the moorings and that created a breach in one of the enclosures.

She said the company was still trying to determine how many fish might have slipped free.

"It's hard to know. I can't put a number on it," said Halse.

A couple of hundred farmed salmon escaped from a breach in an aquaculture pen in Shelburne Harbour last week. (CBC)

She estimated it could be "less than a couple of hundred. We will know once we've done all the harvesting in the area, that whole site."

Shelburne Harbour advocate Shelly Hipson said the release was worrisome.

"Farmed salmon is not a wild fish so here we are allowing something into our environment, into our ecosystem that does not belong there."

Nova Scotia's Fisheries Minister Keith Colwell says officials in his department are "watching it and monitoring the situation."