Environment DNA (eDNA) is a nonlethal sampling method that has potential for evaluating fisheries resources. To evaluate whether eDNA information is useful for fisheries, we collected and analysed eDNA samples from 14 sites in Tokyo Bay from April 2018 to March 2020. Using MiFish universal primers, fish mitochondrial 12S rRNAs were amplified from the eDNA by polymerase chain reaction (PCR) and then sequencing. A total of 535 eDNA samples yielded 44.5 million reads, with 197 of teleosts and 16 of elasmobranchs identified. Of those, 42 identified species were commercially important, with the most abundant being Engraulis japonicus (Japanese anchovy), followed by Konosirus punctatus (dotted gizzard shad) and Lateolabrax japonicusi (Japanese seabass). Mitochondrial cytochrome b copy numbers of K. punctatus and L. japonicus showed a seasonal trend, although catch per unit effort for L. japonicus was not correlated with copy number. Although eDNA is a powerful tool that can detect the presence of fish species from a water sample, caution should be used when interpreting fish biomass based on eDNA dynamics until the method has been better studied.

环境 DNA (eDNA) 是一种非致命采样方法，具有评估渔业资源的潜力。为了评估 eDNA 信息是否对渔业有用，我们从 2018 年 4 月至 2020 年 3 月收集并分析了东京湾 14 个地点的 eDNA 样本。使用 MiFish 通用引物，通过聚合酶链反应 (PCR) 从 eDNA 中扩增了鱼类线粒体 12S rRNA然后测序。总共 535 个 eDNA 样本产生了 4450 万个读数，其中确定了 197 个硬骨鱼和 16 个 elasmobranch。其中，已确定的 42 种具有重要商业价值，数量最多的是Engraulis japonicus（日本凤尾鱼），其次是Konosirus punctatus（点状鲥鱼）和Lateolabrax japonicusi（日本鲈鱼）。K. punctatus和L. japonicus 的线粒体细胞色素 b 拷贝数显示出季节性趋势，尽管L. japonicus 的单位努力捕获量与拷贝数无关。尽管 eDNA 是一种强大的工具，可以从水样中检测鱼类的存在，但在基于 eDNA 动力学解释鱼类生物量时应谨慎使用，直到该方法得到更好的研究。