Exploring Fish Diversity and Environmental Drivers in Québec's Lakes Through eDNA Metabarcoding

ABSTRACT

Fish diversity in temperate freshwater lakes is highly vulnerable to environmental change and overexploitation, necessitating efficient biomonitoring methodologies to track their state and changes. Environmental DNA (eDNA) metabarcoding accurately reflects fish biodiversity in temperate lakes with significant variations in species richness and ecological conditions. Using 12S MiFish‐U primers, this study analyzed DNA in water samples from 65 lakes across Québec. We detected 57 species whose distributions could delineate four distinct clusters of lakes, indicating a nonrandom spatial pattern. Intra‐lake diversity increases westward globally: northern and western Québec lakes hosted the highest species diversity, whereas several eastern and central lakes contain just one to five species. This is consistent with possible post‐glacial dispersal pathways. Finally, we demonstrate the capacity of eDNA metabarcoding to uncover the structuring effects of abiotic and biotic variables, linking temperature, zooplankton species richness, and lake depth to fish community composition in the studied lakes. We also highlight the vulnerability of species that prefer cold, oxygen‐rich waters, such as Burbot and Lake Trout, which are at risk from climate change. This study presents another case study of the utility of eDNA metabarcoding for large‐scale biomonitoring programs, serving as a starting point for a comprehensive monitoring effort across the Province of Québec.