Longitudinal distribution of environmental <scp>DNA</scp> of a salmonid fish, white‐spotted charr <i>Salvelinus leucomaenis</i>, in a small stream

Environmental DNA (eDNA) analysis holds significant promise for monitoring aquatic ecosystems. This study examined the relationship between longitudinal distribution, biomass and eDNA concentrations of Salvelinus leucomaenis in a small stream using conventional electrofishing gear and eDNA analysis in parallel. No consistent trend in the relationship between estimated S. leucomaenis biomass and eDNA concentrations or eDNA fluxes at each 20-m site along the stream was observed, making it difficult to estimate the spatial distribution of S. leucomaenis in streams. However, mean eDNA concentrations across the study area corresponded well with temporal changes in total S. leucomaenis biomass, indicating that multisite sampling using eDNA can be applied to estimate the relative biomass of S. leucomaenis in streams.