ICHTHYOFAUNAL DIVERSITY OF BARJU LAKE, SUNSARI, NEPAL

Abstract

Barju lake is situated at Barju rural municipality of Sunsari district. This study was con ducted from January to June 2022 covering winter, spring and summer seasons. The study area was divided into four stations for fish sampling and physio-chemical parameter was also analyzed. Local fishermen were hired for fish collection in sampling sites using cast net, drag net and traps. A total of 27 fish species (25 indigenous and two exotic) were recorded belonging to seven orders, 14 families and 20 genera. Out of which Cy priniformes (62.97%) and Cyprinidae (57.43%) were the dominant order and family re spectively. Puntius chonchonius was the dominant species followed by Puntius sophore, Mystus tengara, Puntius ticto whereas Channa gachua, Mastacembelus puncalus, Esomus dendricus and Heteropneutes fossilis were found occasionally. The maximum numbers of species were captured during summer season (25) and minimum (10) in winter and site wise maximum species (25) from site II and minimum (10) from Site I and IV respective ly were collected. The highest Shannon diversity index is 3.06 in summer; Margalef’s richness index was 25.82 in summer whereas highest evenness index was 0.52 in spring. The RDA results showed that environmental variables such as pH, free carbon dioxide, DO, Transparency and Water temperature slightly influence the fish community structure. Puntius chonchonius shows strong positive correlation with transparency and dissolved oxygen in Barju Lake, Sunsari, Nepal. Puntius chonchonius, Puntius sophore, Lepido cephalis guntea, Puntius ticto, Mystus tengra and Pseudombasis baculis form disparate cluster as these fish species are most abundant species among all seasons. Although the exotic fish species were cultured there, the abundance of indigenous species was not hampered as the catch was nominal in case of exotic species (% catch indigenous species 97.08% and exotic species 2.91 %).