IMPACTS OF WATER QUALITY ON FINFISH AND SHELLFISH BIODIVERSITY IN THE RIVER MEGHNA

Abstract

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.