Biodiversity Assessment of Freshwater Fish Fauna in Warangal District Telangana State, India

Freshwater fish diversity is a crucial indicator of aquatic ecosystem health, influencing nutrient cycling, food web stability, and socio-economic well-being of communities dependent on inland fisheries. Reservoirs, as man-made aquatic systems, can host a rich variety of native and exotic fish species shaped by hydrological, ecological, and anthropogenic factors. Dharmasagar Reservoir, situated in Warangal District, Telangana State, is a major perennial water body with a water spread area of approximately 20.60 km², constructed primarily for irrigation and drinking water supply, while also sustaining artisanal fisheries. The present study (2017–2018) was undertaken to document the ichthyofaunal diversity of this reservoir and to provide baseline data for sustainable management. Fish sampling was carried out seasonally using traditional fishing gear in collaboration with local fishermen, and species identification followed standard taxonomic keys. A total of 24 species belonging to 10 families and 5 orders were recorded. The order Cypriniformes was dominant with 12 species (50.00%), followed by Siluriformes with 6 species (25.00%), Channiformes with 3 species (12.50%), Perciforme with 2 species (8.33%), and Osteoglossiformes with 1 species (4.17%). The assemblage included commercially valuable major carps (Catla catla, Labeo rohita, Cirrhinus mrigala), small indigenous species (SIS) such as Puntius spp., and apex predators like Wallago attu and Channa striatus, indicating a balanced trophic structure. The detection of exotic species (Cyprinus carpio carpio) points to aquaculture-mediated introductions, whereas the persistence of SIS reflects the ecological integrity of littoral habitats. Comparative analysis with other reservoirs in Telangana indicated similar species richness but a relatively higher proportion of carnivorous species in Dharmasagar, likely due to prey abundance and reduced fishing pressure. This study underscores the ecological and economic importance of Dharmasagar Reservoir, highlighting the need for integrated management strategies—encompassing habitat conservation, regulated fishing, and indigenous species restocking—to sustain biodiversity and enhance fisheries productivity.