Fish diversity of Daraundi River, Gandaki River system, Nepal

Abstract

The present study was carried out to explore fish diversity in the Daraundi River, Gandaki River system, Nepal. The study covered three seasons, including the post-monsoon and autumn of 2023 and spring of 2024. Five permanent sampling sites were selected to collect fish and measure water quality parameters. Fishes were collected using cast net (3 mm to 6 mm mesh size) and hook & line with the help of local fishermen. The collected fish samples were identified by using keys (Shrestha 2019, Jayaram 1977). The study collected 21 fish species belonging to 4 Orders, 6 families and 15 genera, with a total of 780 individuals. Seasonal diversity showed the highest fish diversity in post-monsoon compared to autumn and spring seasons. Cypriniformes was the dominant order with 18 species and 1 each species from Anabantiformes, Siluriformes and Synbranchiformes. This study recorded 14- 23 °C water temperature, DO (7-11 mg/l), Free CO 2 (2-5.2 mg/l), water velocity (1-1.9 m/s), and pH (7.5-10) during its study period. Shannon-Weiner’s, Simpson’s, and Margalef’s was highest during post-monsoon season but Pielou’s evenness was high in spring season. The Karl Pearson's coefficient of correlation affirmed that water temperature, DO and water velocity positively correlated with fish diversity whereas pH and Free CO2 showed negative correlation with fish diversity. This study establishes foundational data crucial for future investigations concerning fish diversity, distribution, and water quality in the Daraundi river of Gorkha district. Keywords: Daraundi River, Fish Diversity, Gandaki River System, Water Quality Parameters