PEWAUKEE LAKE — The Wisconsin DNR says in addition to the dry conditions, some area lakes are seeing a rise in temperatures earlier than usual. Officials say if the heat and dry weather we’ve seen continues, serious problems could develop for wildlife in lakes.
The waters of Pewaukee Lake can be called a swimmer’s dream. While the water temperature is fun for swimming, it’s a different story for fish and other wildlife.
“Lake Michigan is a big system and it’s unusual to have surface temperatures up to 80 degrees. It’s been 80 before, but never this soon. Last year it was a month later before it hit 80,” UWM researcher Val Klump said.
Klump said the heat is more noticeable in a smaller lake, like Pewaukee Lake.
Cold-water fish can swim into deeper water, where it’s cooler.
However, if the hot, dry weather continues, a lake can stratify, meaning warm weather will rise to the top, sealing the lake from the atmosphere. Below the warm-water line, there is less oxygen and in some lakes, there could be none. Experts say fish would have a difficult time surviving.
Researchers say wildlife could already be struggling in some areas due to the weather.
In terms of lake algae development, Klump says the growth is dependent on rainwater runoff and the nutrients it brings into a lake, so rainwater is necessary for excessive algae growth.