While many are out enjoying the nice weather at Wascana Lake, it’s hard not to notice the hundreds of dead fish lining the shores.
“I’m very surprised to see them. I’ve never seen that before — not in those numbers, anyways,” said Leslie Sparling, who walks her dog Grover near Wascana Creek almost daily.
While warmer temperatures, longer daylight hours and, of course, budding leaves are all signs of spring, apparently these dead fish are also a common occurrence.
“We do have dead fish every year,” said Ryan Whippler, acting executive director of the Provincial Capital Commission (PCC). “This year is a little higher than average with the cold winter we had.”
According to Peter Leavitt, a biology professor at the University of Regina, it’s a phenomenon known as “winter kill.”
Even with an aeration system helping to increase oxygen levels, it’s not enough in extreme cold.
“We had a really severe winter, so when you have a cold winter like we did, record cold in February, the ice gets thicker,” Leavitt said. “What that does is it seals the water from the atmosphere and so oxygen that the fish need to breath can’t get into the lake and so the fish suffocate.”
Leavitt added that it’s usually the bigger fish that have more problems, because they require the most oxygen. Smaller fish, however, are biologically equipped to better deal with low oxygen levels.
The most common type of fish dying are carp — which, Leavitt says, are more or less just goldfish people have dumped into the lake.
“Generally speaking there’s much more to eat there than what they get in an aquarium environment, so they tend to grow as large as they’re capable of,” Leavitt said. “Given that the species isn’t native to the lakes here, it’s no big loss.”
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In fact, Leavitt says it can actually be beneficial to the overall water quality, which has been stable for the past decade. The university will continue to take samples from the lake starting in May.
“There’s no sense that all of a sudden things have gotten catastrophically worse, so I would say to people that fish kills may be unpleasant but it’s the cycle of life,” Leavitt said.
The PCC is sending out crews to clean up the fish periodically, but are asking people if they come across the dead fish not to move them.
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