water metagenome
The sampling was conducted in the Changqing Nature Reserve, which is located in the Qinling area of Shaanxi Province within the Giant Panda National Park in central China. The sampling occurred from May to June 2021. A total of 29 sampling sites were established, distributed across three administrative regions of the reserve. Specifically, there were 10 sampling sites in the Huangguan region, 11 in the Changqing region, and 8 in the Sangyuan region. In addition to collecting water samples for eDNA analysis, fish were captured using the traditional method of electric fishing. The range for electric fishing was randomly selected and extended from 50 meters to 200 meters upstream. Water samples were collected at a distance of approximately 3 meters from the shore using disposable water bags. At each sampling site, a 3-liter composite water sample was collected, which included water from the surface, middle, and bottom layers of the water column at depths ranging from 0 to 1 meter. Each of these composite samples had three replicates. During the entire sampling process, operators were required to wear disposable sterile gloves, and the gloves were replaced before each new sample was collected. Right after the collection of water samples, a portable water sampler was used along with disposable glass fiber filter cups. These cups had a pore size of 0.45 micrometers and were used for filtration. After completing the filtration, the filter papers from each cup were folded and then stored in anhydrous ethanol. When returned to the laboratory, the filter membranes were stored at a temperature of minus 80 degrees Celsius.