Die-off concerns low despite photos

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This article was published 02/04/2019 (1455 days ago), so information in it may no longer be current.

Photos of thousands of dead minnows in Pelican Lake circulated on social media have raised concerns, but the chair of the lake’s health committee said it’s nothing to be concerned about.

“So far, if it’s the minnows that we’ve seen, that would even be a fraction of a per cent. It’s tiny. The lake is 7,000 acres and we’re talking about a spot that was a few hundred square feet. … It’s OK, we were out testing on Friday, oxygen on the lake is fine,” said Trevor Maguire, chair of the Healthy Lake Committee.

The photos were posted in the Facebook group Manitoba Ice Fishing and show thousands of dead minnows — and a few larger fish — washed up on the shore of the lake. Attempts to reach the user who posted the photos were unsuccessful.

The minnows may have died while trying to swim upstream. Maguire said they won’t know more until more ice thaws, but they may have gotten trapped in a pocket of water after ice moved in. The actual cause of death could be oxygen depletion in that particular pocket, or the water freezing solid.

“If there’s fish caught in little pockets, they just get frozen and there’s nothing you can do about it. The lake is in great shape, the water is in great shape.

The large number of dead fish is part of a natural cycle the lake sees every winter in the south end. The water is shallower there, so deep freezes during the winter have a bigger impact on the habitat and it’s harder to keep oxygenated.

In fact, the cycles were much more frequent before the town installed an aeration system on the lake in 2012 to keep it oxygenated year-round.

While Pelican Lake is in good shape, Maguire said the long winter and frigid temperatures could create die-offs in smaller, shallower lakes in the region. A thick ice cover keeps the water from taking in oxygen from the air during the spring, and snow on top blocks out sunlight, killing plant life on the lake bed. This creates a vicious cycle where the dead plants create toxic gases, which kills off fish, which then decompose and create more toxic gases.

“It’s going to show why you need to aerate these Prairie lakes because once it dies, it takes years for the ecosystem to rebound. It’s not just the fish that are dying, it’s the fish, it’s the snails, it’s the crayfish, it’s the plants — everything gets in trouble, and it takes so long for the lake to come back.”

West Souris Conservation District manager Dean Brooker said that while it’s an issue he’s watching, he hasn’t heard any reports of die-offs as of yet.

“We’re definitely watching it, there’s not much we can do about it to control it, I haven’t heard of anything yet but you just have to wait for the ice to disappear and wait to see if there’s a fish die-off.”

Throughout the winter ice fishing was good on Oak Lake, so the fish appear to be healthy.

Hills Conservation District manager Neil Zalluski said he hasn’t yet been out to check on the lakes, but this winter was long and cold, which isn’t good for the fish.

Once the ice cover melts, oxygen and sunlight will be allowed into the lakes, which he said will help the fish populations rebound.

In the coming days, Maguire said he will know more about the condition of the area of Pelican Lake where the minnows appear to have died, but said he is confident the overall health of the lake and most fish in it is very good.

“As this develops over the next few days … we’re kind of curious to see how big this is going to turn out. There’s nothing I can do about (the die off). I know the water is in great shape because I tested it.”

» dmay@brandonsun.com

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