Thousands of dead fish have turned up at a lake northwest of Rocky Mountain House.

Thousands of dead fish have turned up at a lake northwest of Rocky Mountain House.
There's a pungent smell at a lake northwest of Rocky Mountain House, where thousands of dead fish line the shore. Many are now worried bears living around the area will be drawn, as the local birds and bugs have been, to a feast of rotting perch.

People with cabins along Crimson Lake said they started noticing the dead fish as the ice began to recede this spring.

"Crimson Lake has a history of 'winter kill' as a result of the shallow depth of the lake," Alberta Environment and Parks said in a statement.


Winter kill occurs in frozen lakes and ponds where the exchange of gases between the water below the ice and the air above is not enough to maintain oxygen levels that support fish. Crimson Lake is only a couple of metres deep, on average, and ice and snow covered the lake longer than usual this past winter.

But where the fish came from in the first place is still unclear.

Residents suggest the lake was stocked with trout by the province years ago, but the warm shallow water proved to be a poor fishery. The province said the lake is managed "to maximize opportunity, given the frequency of winter-kill events."

It was only in the last few years that residents started seeing fish again, with ice fishing growing in popularity this past year. Many who live there suggest the lake was illegally stocked with perch by someone hoping to improve fishing prospects, but no charges have ever been laid.

"Alberta Environment and Parks will assess this event to determine if the die-off was complete or partial, and consider management actions once this determination has been made."

Officials with the province were there Monday, cleaning up some of the dead fish. The ministry suggested, "Mother Nature will clean up [the rest] in short order."