Fish Composition, Diet and Water Quality of Murum River Above and Right Downstream of Murum Hydroelectric Power House, Belaga, Sarawak

A study on freshwater fish composition, diet and water quality was conducted above and right downstream of Murum Hydroelectric Power House, Belaga, Sarawak to compare the diversity and distribution of fish fauna and selected water quality parameters between the two locations. Fish samples were collected using gill nets of different mesh sizes and three-layered nets. The two locations showed different fish composition with Cyprinidae family dominating both areas. The dominant species are Osteochilus hasseltii (N=45), followed by Cyclocheilichthys apogon (N=32) and Barbonymus schwanenfeldii (N=27). Station 1 recorded a higher Shannon-Wiener's Diversity Index and Margalef’s Species Richness Index in comparison to Station 2. Cyclocheilichthys apogon and Barbonymus schwanenfeldii are omnivorous while Parachela oxygastroides is carnivorous based on stomach content analysis. Length-weight relationship showed that Osteochilus hasseltii showed negative allometric growth (b=2.965) while Cyclocheilichthys apogon showed isometric growth (b=3.018). Water quality analysis showed that pH, DO and chlorophyll-a were significantly lower while ammonia, nitrite and hydrogen sulphide were significantly higher in Station 2 compared to Station 1. Based on Water Quality Index (WQI), river water for Station 1 is categorized under Class II and is considered clean, whereas Station 2 is classified under Class III and is considered slightly polluted