Impacts of Water Quality on Finfish and Shellfish Biodiversity in the River Meghna

Fish biodiversity largely depends on different environmental factors including water quality parameters. The current study was conducted to investigate the impacts of water quality variables on fish biodiversity at upstream and downstream of the river Meghna in dry and rainy season in 2011. Twelve water samples and 66 fish samples were collected from 2 different sampling stations of the river Meghna during the study period where 61 were finfish species and 5 were shellfish species. The number of finfish and shellfish catch at upstream in both dry and rainy seasons were significantly higher than that of downstream (p<0.01). Shannon-Weiner index and species richness were determined where significantly higher Shannon-Weiner index was observed at upstream in dry season than that of downstream (p<0.01) and similar species richness was observed at upstream and downstream in both of the seasons. Significant correlation was observed between physicochemical parameters and the fish biodiversity indices. The obtained results suggested that the changes in environmental parameters of water including conductivity, pH, DO, BOD had significant impacts on Shannon-Wiener indices at downstream which indicate the water quality detarioration. This findings have the implications in designing polices to sustain the finfish and shellfish biodiversity and to mitigate the environmental changes in the river Meghna. Dhaka Univ. J. Biol. Sci. 31(1): 19-27, 2022 (January)