South Okanagan resident Keith Coules goes for a swim in Osoyoos Lake every morning, but over the past ten days, he’s noticed something bizarre.
Dozens if not hundreds of salmon have been washing up on Osoyoos beaches.
“We noticed a lot of dead salmon in the lake and then washing up on the beach regularly. Just in our section of property, counted about 100,” said Coules.
“We’re not sure what’s happening, whether it’s the water temperature or lack of oxygen. A friend suggests there might have been a lightning strike that killed the fish.”
Senior Biologist Richard Bussanich with the Okanagan Nation Alliance refers to it as “the squeeze.”
“The squeeze that I’m talking about is there are warmer water temperatures near the surface exceeding 21 degrees Celsius. Down in the bottom and near the sediment and moving up into the water column, you have these lower oxygen conditions,” said Bussanich.
According to Bussanich, historically and more recently with warming temperatures, the window gets smaller, particularly in August.
Over 400,000 Okanagan salmon are destined for Osoyoos Lake and about 40 have been washing up each day this week.
“The conditions for salmon-friendly oxygen and temperature have completely collapsed now, so as of the last few days, where you’re seeing fish kills,” said Bussanich.
“Any fish deaths are of concern to our members and nations and rightly so. It’s for us, it’s not a numbers game of one versus 5,000, but all fish and all life are important, so we are continuing to monitor it.”
The Okanagan Nation Alliance has received reports from other residents but says this isn’t the first-time fish kills have occurred in Osoyoos Lake.
There are other factors like natural, non-natural or human-caused fish deaths, but Bussanich said crews are actively monitoring salmon throughout the region.