A Tele02F-Tele02R project for fish based on environmental DNA technology

In this study, the Chongqing section of the lower reaches of the Fujiang River Basin is divided into six isolated reaches by five DAMS , including Shuangjiang (SS) reservoir area, Tongnan (ST) reservoir area, Fujinba (SF) reservoir area, Anju (SA) reservoir area, Weituo (SW) reservoir area and Weituo River confluence section (SWX) . Three sampling points were set up in each reservoir area, and 18 sampling points were distributed at the head, middle and end of each reservoir area.Water samples were collected in May 2023(a), September 2023(b), and January 2024(c).At each sample point, a plexiglass water sampler was used to collect 3L mixed water samples from the head, middle and end of the reservoir, as well as the upper, middle and lower water layers. Then, the water samples from three sampling points in the same sampling section were mixed, and 6L of the mixed water samples were divided into 3 parallel samples on average (every 2L of water sample was used as 1 parallel sample), with a total of 54 water samples, and the remaining water samples were discarded.The PCR products were subsequently gel-purified and sent to a commercial company for high-throughput sequencing on the Illumina NovaSeq 6000 platform, employing a paired-end sequencing approach, where both ends of each DNA fragment were sequenced. The length of each read is 150 base pairs (bp).