Diversity and Distribution of Fish in Andhi Khola, Syangja District, Nepal

Abstract

Seasonal changes in the species composition, number and abundance of fish species in Andhi Khola were investigated from September 2018 to May 2019. This study also addresses the relationship between fish and environmental variables from the Andhi Khola. Out of 907 individual fish identified, represented a total of 15 different species belonging in four order 11 genera and six families were caught. Highest number was counted for Barilius barila (320) and lowest was Heteropneustus fossilius (2 individual) which are 35.28% and 0.22% of total individual respectively. Along the longitudinal gradient from headwater to downstream, fish species richness and abundance increased gradually, but then decreased significantly at the lower reaches. The highest species richness and abundance were observed in spring and the lowest in winter. The highest value of Shannon-Weiner diversity index (1.96) was found in spring season and lowest (1.69) was found in winter season. Highest value of evenness index (0.35) was found in autumn while lowest (0.31) in winter season .The Simpson dominance index in different sites varies from 0.75 to 0.79. The highest Simpson dominance index (0.79) was recorded at site I and site II and lowest (0.75) was recorded at site III. Highest Simpson dominance index (0.81) was recorded in autumn and lowest (0.73) was recorded in winter. The Redundancy analysis (RDA) revealed that the environmental variables of water temperature, water velocity, and dissolved oxygen were found to be most imperative variables to shape the fish assemblage structure of present study area.