Fish Fauna Composition of Bakun Reservoir, Belaga, Sarawak

This study was conducted to document the fish fauna composition of Bakun reservoir. Seven sampling stations selected were located at Sungai Bulo and its tributaries, Sungai Wat, Sungai Murum, Sungai Linau and Sungai Pelepeh and its tributaries. The sampling methods used in this study were gill net of different mesh sizes, hook & line, cast net and electro-shocker device. A total of 1,177 fish individuals were caught consisting of 6 families, 19 genera and 34 species. Cyprinidae was the dominant family among the six families representing 87% of the total number of individual caught where Barbonymus schwanenfeldii was dominant with a total of 230 individuals or 24.4% of the total number of individuals caught. Station 1 account for the most fish individuals caught with a total of 384 individuals or 34.8% of the total individuals caught and the lowest number of individuals caught was in station 3 with a total of 32 individuals or 2.72% of the total individuals caught. The highest species diversity was at station 1 with a value of 1.06 and the highest richness index was at station 5 with a value of 9.15, whereas the highest evenness index was at station 3 and station 4 with a value of 0.38. Fish fauna composition was influenced by the habitat characteristics of the river as well as the adaptation of the fish to newly created lentic environment since the impoundment of the Bakun reservoir