Prescott National Forest officials are discouraging visitors from swimming in several lakes due to area fish die-off.
A statement released Friday issued a warning for Mingus, Granite Basin, and Horsethief Basin lakes.
Forest officials say a high volume of vegetation grew near Granite Basin Lake over summer, creating an abundance of decomposing plants. The result, according to PNF, is a higher level of biochemical oxygen demand.
“The consequence of high [biochemical oxygen demand] causes low dissolved oxygen that stresses aquatic organisms,” PNF wrote in a statement Friday. “This has ultimately resulted in fish kill at Granite Basin Lake.”
Forest officials say the occurrence is a natural process, and that an investigation is ongoing. PNF, meanwhile, urged people to avoid “wading and full body contact” in area lakes.