Spatiotemporal of fish assemblage structure Pathariya river of Kalali district, Farwestren Nepal

Abstract

The spatial and temporal variations of the fish assemblages in Pathariya River, Western Nepal is poorly understood. To examine the fish assemblage structure, fish samples were collected in seasonal basis from four sites of the river by using cast net and gill net. A total of 407 individuals belonging to 4 orders, 8 families, 16 genera and 25 species were collected from Malbhanga, Thakurwdara, Sonalipur and Dhunganatol of Pathariya River. Majority of the fishes belonged to the family Cyprinidae (53.56 followed by Bagridae (17.44, Mastacembelidae (11.31 Channidae (8.11, Cobitidae (5.65, Claridae (1.72, Nandidae (1.47 and Siluridae (0.74. The most abundant species were untus tcto untus sohore, and Mystus tengra The highest diversity index (2.96 and species richness (22 of fish were recorded from station D (Dhunganatol in autumn season (September. Lowest diversity index (1.67 and species richness (6 were found in station A (Malbhanga during the spring season (March. The redundancy analysis (RDA revealed significant correlations between fish assemblage and environmental variables The environmental variables such as transparency, dissolved oxygen, pH, hardness, velocity, and temperature were most strongly correlated with the fish community composition. The difference in fish assemblage structure and diversity in Pathariya River are probably related to habitat type, altitude, season, several environmental factors and anthropogenic activities.