Walleye, a culturally, economically, and ecologically important gamefish in much of North America, has experienced declines in recent years. The cause of these declines is not well understood , but is likely due to a combination of factors, including rising water temperatures, increased water clarity, loss of habitat, harvest, and species interactions. As part of a multi-year project, we are exploring the role of these factors in causing Walleye declines through the analysis of long-term data, simulation modeling, and a whole-lake experiment. We hope to understand conditions needed to maintain self-sustaining Walleye populations and inform recreational fisheries management.
Temperature & Habitat
Analysis of long-term data from northern Wisconsin has indicated that due to a changing climate, the number of suitable Walleye lakes will decrease, while potential warm-water competitors (e.g., Largemouth Bass) will have increased habitat. To find out more about this research and other related analyses:
Using long-term data from northern Wisconsin, we are exploring how life-history changes, such as growth, may be resulting in declining Walleye, specifically the low survival rate of young Walleye. As part of this, we found that not only are Walleye numbers declining, but the amount of Walleye created annually (i.e., the production rate of Walleye) is also declining. To learn more about this work:
Interactions between Walleye and other fish may be playing a large role in Walleye's ability to maintain self-sustaining populations. We have looked at this through simulation models, observational studies, and are beginning a whole-lake experiment to determine how other species may be affecting Walleye. To read more about past work:
In combination with the other factors threatening Walleye, we are exploring the role of harvest in these declining populations. We found that as the growth rate of populations declined, harvest has remained at the same high levels through time. This has resulted in more overharvest and emphasizes the need to adapt Walleye harvest management as unmanageable factors, like rising water temperatures, diminish the ability for Walleye to maintain self-sustaining populations. To learn more about this work: