Development of a multiplex real time-PCR assay to estimate the distribution of the genus Silurus in Lake Biwa using environmental DNA

Three species of catfish, Silurus biwaensis, Silurus lithophilus, and Silurus asotus, are identified in Lake Biwa. Notably, S. biwaensis and S. lithophilus are endemic species in Lake Biwa; however, their detailed distribution and ecology almost remain unknown. In this study, we developed catfish species-specific primer probe sets based on their whole genome. Using these, we analyzed the water samples collected from three tanks where S. biwaensis, S. lithophilus, and S. asotus were experimentally reared, respectively, and established a new detection system after confirming each primer probe set to be effective. Finally, we conducted environmental DNA analysis for catfishes in Lake Biwa using field samples. Overall, our results showed that environmental DNA analysis is a useful monitoring method for confirming the presence of endemic catfishes in Lake Biwa.