MASON CITY – A fish kill taking place Saturday in a Mason City park is being caused by low oxygen levels also known as oxygen sag.
The fish kill was investigated by the Iowa Department of Natural Resources at Black Pit, a 16-acre pond in Lester Milligan Park on the southwest side of Mason City. Stressed fish of different species were observed on Friday with dead fish beginning to appear on Saturday. Water samples taken on Saturday indicated low oxygen levels.
The water at Black Pit is also currently experiencing an algae bloom. When algae blooms occur, the oxygen in the water can be greatly reduced causing fish kills.
3 thoughts on “Oxygen sag likely cause of fish kill in Mason City’s black pit”
With all the unemployed, lazy, rif raf hog dogs swimming in the pits it is no wonder this happened
Lovely algae blooms are fueled by fertalizer, both agricultural and the crap people throw on their lawns. Decreased oxygen levels can also happen when rain carries lawn clippings into the storm sewers. The clippings wash into streams and decay. This decay requires oxygen. As oxygen levels drop, aquatic life dies. People, it’s illegal to blow your lawn clippings into the street in Mason City. Please stop it.
I never blow my lawn clippings in to the street, that would create a traffic hazard, I simply like to bag them and then safely dispose of them in bodies of water.