Somatic growth of pikeperch (Stizostedion lucioperca) in relation to variation in temperature and eutrophication in a Central Europe Lake

Global climate change has been altering freshwater ecosystems by impacting many ecological processes, including individual fish growth. Predictions of responses of local fish populations to future environmental change can draw inferences from past long-term biochronological data. In this study, we reconstructed individual growth pattern of one of the most valuable predatory species in European inland waters, pikeperch (Stizostedion lucioperca), using back-calculated length from their otoliths. Samples were collected at the Lipno reservoir (Czech Republic) between 2008 and 2020. We used linear mixed-effects models to investigate how individual state and environmental conditions affect the somatic growth of the local pikeperch population. We found that individual growth rates increased with temperature and tended to be higher when chlorophyll-a concentration was higher, and water transparency was lower. This suggests the species will likely benefit from the warmer waters predicted in future climate scenarios. However, the decreasing nutrient loading associated with efforts to curb eutrophication in Central Europe may offset these benefits. Together, these results provide a better understanding of how multiple environmental factors, directly and indirectly, influence the somatic growth of pikeperch in long term.