UTTAR PRADESH JOURNAL OF ZOOLOGY

Rivers, lakes, reservoirs, and floodplain ecosystems contribute significantly to the rich aquatic biodiversity of Maharashtra. Hetwane Reservoir, located in Pen Taluka of Raigad District, Maharashtra, is an earth-fill dam constructed across the Bhogeshwari River. The reservoir has a catchment area of approximately 6,740 ha, a dam length of 675 m, and a maximum height of 48.2 m. It has a gross storage capacity of approximately 147.49 million m³ and a live storage capacity of 144.98 million m³. The reservoir serves important purposes including irrigation and water supply. The present study was undertaken to document the ichthyofaunal diversity of Hetwane Lake and to assess the status of its fish assemblage. A total of 34 fish species belonging to 14 families were recorded during the study. The family Cyprinidae was the most diverse, with 13 species, followed by Channidae with four species and Anabantidae with three species. The families Bagridae, Centropomidae, and Notopteridae were represented by two species each, while Amphipnoidae, Belonidae, Clariidae, Cobitidae, Mastacembelidae, Saccobranchidae, Siluridae, and Tetraodontidae were represented by one species each. Preliminary information obtained through interactions with local residents and fishermen indicated an apparent decline in the abundance of several formerly common species, including Clarias batrachus, Wallago attu, Channa striata, Notopterus spp., Mystus spp., and Mastacembelus armatus. These observations highlight the need for systematic long-term monitoring to understand changes in fish diversity and abundance and to develop appropriate conservation strategies for the ichthyofaunal resources of Hetwane Lake.