Response of yellow perch to water level fluctuations in oligotrophic, north-temperate inland lakes

Information on yellow perch Perca flavescens population dynamics and responses to various abiotic and biotic factors in oligotrophic, north-temperate inland lakes is limited. Water level fluctuations are known to influence available habitat and biological communities within the littoral zones of lakes, yet research is lacking for yellow perch in Wisconsin. The goal of our study was to characterize yellow perch population-level responses to natural water level fluctuations in four northern Wisconsin lakes using a 39-year time series. On average, increasing water level periods correlated with lower mean fyke net and gill net relative abundances (catch-per-unit-effort), though generally not statistically significant. Yellow perch mean relative weight varied among lakes and was significantly greater during increasing water level periods for all lakes except one. The lack of statistically significant findings potentially suggests a buffering mechanism of north-temperate oligotrophic lakes due to their small surface area to volume ratios, relative lack of nutrients, and(or) littoral structural habitat compared to other systems (e.g., shallow eutrophic lakes). Our results suggest that natural water level fluctuations may not be an environmental concern for yellow perch populations in some north-temperate oligotrophic inland lakes.