Fish Diversity of Sapta Koshi River, Saptari, Nepal

Abstract

The physio-chemical parameter of an aquatic environment exhibit influencing factor for the quantity of aquatic life. Present study (a ranging of 2.5 km) during the month of February and May 2015 in the Koshi River indicated a total account of 22 fishes species from 6 orders namely Anguilliformes (1.73%), Clupeiformes (1.73%), Cypriniformes (48.95%), Siluriformes (35.41%), Synbranchiformes (3.47%) and Perciformes (2.08%) of fish species out of 288 fish catch recorded 10 families and 17 genera. The most abundant family within catch was Cyprinidae. Aspidoperia morar, Clupisoma garua were the most abundant fishes in all the study sites during the month of May. Labeo rohita, Puntius sophore, Mystus tengra were the most abundant fishes in all the study sites during the month of February. Fishes belonged to different families like- Anguillidae (1.73%), Clupeidae (1.73%)), Cypinidae (46.52%), Cobitidae (2.43%), Bagridae (17.36%) , Schilbeidae (7.98%) , Clariidae ( 3.13%), Heteropneustidae (6.945) , Mastacembelidae (3.47%) and Channidae (2.08%).Here, occurrence of Cypriniformes - Labeo spp. Cirrhinus comprises the dominant group. One species belonging to Heteropneustidae family in the Koshi River during this investigation but Anguillabengalensis, Labeo dero, which were not reported from Koshi River. Number of fish species was recorded higher in stations I and III and lower in station II. The correlation between transparency and fish density was found negative at station I and positive at II and III. The transparency was change in the water depth and human activities. The study showed riverine environment undergone degradation due to various natural landslide, soil erosion and manmade activities like road construction alongside of the river bridge, construction, over fishing, illegal fishing, use of soap and detergent, stone extraction etc