Eight years of weekly eDNA monitoring in the North-Western Pacific

Detection of marine organisms based on environmental DNA (eDNA) has expanded the knowledge of species richness, distribution, and appearance patterns. We used eDNA data from a single location sampled weekly over 8 years to detect as many species as possible, and investigate their appearance patterns and associations with biotic and abiotic factors. We detected >2500 operational taxonomic units (OTUs) associated with unique species from nine supergroups. The dominating currents that differ significantly in temperature, salinity, and nutrient concentrations structured the richness of the OTUs. We further detected sporadic and seasonal or continuous presence among the OTUs connected with a single species. This study shows that the long-term eDNA-based monitoring approach provides comprehensive knowledge of the species present as well as their associations with biotic and abiotic factors.