環境DNA分析を用いたアユ産卵場の適切なモニタリング手法の構築

～時間的検討を中心に～

抄録

The resources of Plecoglossus altivelis, the most important fishery target species in Japanese rivers, have been recently decreasing. A simple method to monitor spawning ground is required to conserve P. altivelis resources. In this study, we conducted: (1) five daytime samplings of environmental DNA (eDNA) at six sites during the spawning season of 2017; and (2) continuous samplings of eDNA at one site for three days from 15:00–22:00 during the spawning season of 2018. Our results showed that, even in the high spawning season, the values of eDNA concentration and flux may be small on some days, and the main spawning ground may change during the season. Moreover, we found that P. altivelis was more likely to be actively spawning on days with high tide fluctuations, and eDNA concentration was highest approximately 45 minutes after sunset on the day of high spawning activity.