ASSESSMENT OF PHYSICO-CHEMICAL PARAMETERS AND ICHTHYOFAUNAL DIVERSITY OF RIVER TORSA - SEASONAL AND SPATIAL VARIATIONS

The Torsa River is an important tributary of the Brahmaputra running through West Bengal, and it plays an important role in the ecology, biodiversity, and sustenance of the human population in the region. This study aims to evaluate the physicochemical properties and ichthyofaunal diversity of River Torsa in order to assess its sustainability and ecological health. Sampling was done at three sites along the river and during the pre-monsoon, monsoon, and post-monsoon periods. The physico-chemical parameters evaluated include temperature, pH, dissolved oxygen, free carbon dioxide, velocity, conductivity, TDS, total alkalinity, total hardness, and chloride. Using a cast net and a gill net, fish samples were collected and identified. Furthermore, the catch per unit effort (CPUE), diversity, evenness, richness, and dominance of the fish species were also calculated. The findings revealed both spatial as well as seasonal variations in the water quality; however, overall, the water was found to be suitable for supporting aquatic life. A total of 113 fish species belonging to 28 families were identified. There were no significant differences identified in the fish species among the three sampling sites. The findings of this study point towards the need for continuous monitoring of the quality and diversity of River Torsa and the implementation of conservation strategies to maintain the river’s ecological balance.