Monitoring fish diversity and the emergence of southern species in Northeastern Japan using environmental DNA

Abstract

Environmental DNA (eDNA) is genetic material released by organisms into their surroundings. In recent years, eDNA has increasingly been used to assess species distribution, biodiversity, and even to estimate biomass in aquatic ecosystems. Along the Japanese coast, rising sea surface temperatures and environmental changes have led to declines in fishery resources and shifts in species composition. Accurate evaluation of current biodiversity is essential for sustainable fisheries and proper resource management. In this study, eDNA monitoring in Moune Bay, Kesennuma, Miyagi Prefecture, revealed both seasonal and spatial changes in fish communities. The results demonstrated a clear association between rising water temperatures and the appearance of southern fish species. These findings highlight that eDNA-based approaches are highly effective for estimating fish diversity in coastal areas. Furthermore, we discuss the potential applications of eDNA data for the utilization of unused fish resources.