Grayslake – In the Wildwood neighborhood of unincorporated Grayslake, large amounts of dead fish have washed upon the shore. Dead small mouth bass, bluegill and crappie can be seen lining the shoreline in every part of the lake. Residents began to notice the occurrence early this week.
The Wildwood Park District and Lake County Health Department have been working with the Illinois Department of Natural Resources to identify the cause of the fish kill.
On Wednesday, the Lake County Health Department measured dissolved oxygen (DO) content at the surface and a foot down. At the surface, a reading of 1.5 mg/L of dissolved oxygen was obtained and 0.6 mg/L was measured at a foot below. Levels below 5 mg/L can be hazardous to a fish population.
The Park District cited several potential causes for the drop in DO. Water in the summer is hotter which reduces the DO levels. Heavy rain events such as what has happened lately can wash heavy amounts of organic material into surface water bodies which consumes oxygen as it decays. Combined, this can lead to a crash in dissolved oxygen levels.
The Wildwood Park District is working to address removing the fish and will provide updates as available.
