Environmental DNA (eDNA) sampling strategies influence estimates of lake fish eDNA concentrations

Environmental DNA (eDNA) is increasingly used to estimate species abundance and biomass, but impacts of sampling strategies are poorly understood. We compared point and spatially integrated sampling, two commonly used sampling strategies, in two lakes using quantitative eDNA analysis. Integrated sampling increases the spatial coverage and the total volume of water sampled relative to point sampling. However, integrated sampling led to lower fish eDNA recovery and underestimated eDNA concentrations compared to point sampling. Although the exact mechanisms underlying this pattern require further investigation, these results underscore the importance of aligning sampling strategies with key study objectives.