2.2. DNA isolation

Water samples were filtered through 47mm dia 0.2 μm polycarbonate filter paper, and the eDNA was isolated using DNeasy PowerWater Kit (Qiagen). Briefly, the filter papers were homogenised with 5ml of lysis buffer and incubated for 90 min, and the mixture was centrifuged at 4000g for 5 mins at 4 °C. The supernatant was collected in a separate fresh tube, and the DNA was precipitated by adding ice-cooled 0.7 vol isopropanol. The isolated DNA was pooled together, and the quality was checked in agarose and NanoDrop 2000/2000c (Thermos Scientifics). The extracted DNA was sent to the Xcelris Labs Ltd, Ahmedabad, India, for amplicon sequencing.