During a comprehensive fish survey which included spring, summer and fall netting and electrofishing surveys, Greg Matzke, a fisheries biologist for the Wisconsin DNR discovered that all of the lake’s largemouth bass were older than 5 years of age. After intense sampling last year, only one black crappie was under six years of age and there weren’t any northern pike under the age of eight.
Matzke also found that the lake’s panfish population had declined an estimated 75% in the last ten years. The fish population of Lake Ellwood wasn’t reproducing and the decline coincides with herbicide treatments of the lake. 2,4-D was used to treat aquatic plants, namely Eurasian watermilfoil beginning in 2003. While the reduction of the aquatic invasive species has been significant the chemical treatment has also harmed native plants. The plants that are necessary for young fish to survive.