A puzzling aquatic mystery is happening in the town of Canmore, west of Calgary.
Fish in Spring Creek are going belly up for an unknown reason.
Residents started talking about the strange occurrence on Monday through social media, and the town began receiving reports of dead fish on Tuesday.
The phenomenon might sound mysterious, but Tom McMillan believes there’s a simple explanation.
McMillan is the Director of Communications for Alberta Environment and Protected Areas. He thinks “winter kill” can explain the town’s fishy mystery.
Winter kill refers to the unfortunate situation where a large number of fish die in lakes and wetlands that have been overwhelmed by algae and weeds.
Winter Kill?
Fish need oxygen to breathe; just like us, they rely on oxygen-producing aquatic plants and algae to survive.
But light can’t penetrate the surface when bodies of water become covered in thick ice and snow.
Aquatic plants and algae rely on sunlight for photosynthesis, which enables them to produce oxygen efficiently.
If the plants can’t photosynthesize, then oxygen levels drop.
Fish die off when oxygen levels get too low.
Something similar happened in January last year when thousands of dead fish were found in Vermilion Lakes near Banff.
Parks Canada investigated the incident and found that the oxygen levels of the lake were very low, which resulted in the mass die-offs of white sucker and brook stickleback fish.
Recovery Possible?
Some fish are more vulnerable to winter kill than others.
For example, trout require more oxygen and get stressed at lower oxygen levels.
The two primary species of trout in Spring Creek are Brook and Brown.
In the current General Status of Alberta Wild Species report, these species are classified as exotic/alien and are not endangered.
In other words, Spring Creek’s trout population should have no problem recovering because fish can migrate into the stream from the Bow River.
According to McMillan, the Ministry is sending a team to investigate the cause of dead fish in Spring Creek.
“While winter kill is a fairly common occurrence at this time of year, we cannot speculate on causes until the biologists have had a chance to complete their work,” said McMillan.
Canmore is also conducting research and will share any findings with the Ministry.
The cause of dead fish in Spring Creek is still unknown, but winter kill is the likely culprit.
With both the Ministry and Canmore looking into the incident, an answer will soon surface.
