The fish play an important role in the life of rural folk in Garhwal Himalaya as it is a cheaply available protein rich source. In the present communication an attempt has been made to study the spatial distribution, density and diversity of fishes in three different sections of river Mandal in Pauri Garhwal. The study was based on two spots in upper rhithon section, two spots on lower rhithron section and one spot in the lower potamon section. It was observed that the middle stretch (Lower rhithron zone) was more diverse and productive where fish productivity was 46 CPP at Spot no 3 (19 species) and 34 CPP at spot no 4 (13 species). Upper stretch of the river was less productive. The lowermost section has low diversity in term of taxon but the biomass production was maximum. Overall 20 taxa were observed wit the dominance of family cyprinidae with 10 taxon and cobitidae with 7 taxon. Channidae was represented by 2 taxon and family balitoridae, ambliceptidae and mastacembelidae by 1 taxon each. Diversity was assessed with the help of Simpson, Shannon and Wiener, Menhinick, Margalef and equitability J indices. Multivariate analysis was done with the help of cluster and principal component analysis. Some detrimental ecological parameters were also analysed which had either positive (pH and temperature) or negative (velocity of water current and dissoved oxygen) impact on fish population.
