Researchers at the Wisconsin DNR are looking for answers as to why walleye populations are declining in the state.
DNR Research Scientist Gretchen Hansen says adult walleye numbers are declining statewide by an average of two percent per year.
“So there’s a lot of variability. So in some lakes, populations are going up, but in the majority of lakes populations are going down. And a lot of that is driven by failed recruitment, so failed reproduction.”
DNR research into lakes with naturally reproducing populations has revealed that walleye are reproducing better in bigger lakes, as well as ones with cooler or shorter growing seasons.
It’s not entirely clear why those factors result in better reproduction, but it does allow researchers to predict what might happen in certain lakes.
Hansen says the next step in the project is an adaptive management experiment…with some lakes regulated for restricted walleye harvest, higher bass harvest, and getting stocked with large fingerlings.
“And then another set of the lakes are not getting any of those treatments, and we’re going to monitor them over the next decade, and see if hitting them with those three management responses can change the trends at all, or if we need to look to more habitat-oriented interventions or something.”
Hansen spoke at a conference last week in Boulder Junction that focused on Science in the Northwoods.