Seasonal Fluctuations in Physicochemical Parameters in Relation to Fish Diversity in Muragacha Beel, West Bengal India

The present study was made to find out the health status of Muragacha Beel, District North 24 Parganas, West Bengal, India. The study focused on the seasonal fluctuation of physicochemical parameters of water and diversity of fish fauna during pre-monsoon, monsoon, and post-monsoon from March 2019 to February 2020. Water samples and fish specimens were collected from three different sites of the beel every month to evaluate the correlation between physicochemical properties of water and the indices of fish diversity. A significant seasonal fluctuation in fish diversity (2.762-2.796) in relation to physicochemical parameters (temperature 20.2-32.8 degrees C, turbidity 23.1-30.1 cm, pH 7-8.5, carbon dioxide0-15.6 mg/l, dissolved oxygen 4.5-5.9 mg/l, biochemical oxygen demand 2.6-7 mg/l, alkalinity 148-194 mg/l, hardness 106-168 mg/l, phosphate 0.43-1.25 mg/l and nitrate 0.17-0.45 mg/l of water) was recorded during the study period. In respect of fish faunal diversity, a total of 25 species belonging to 6 orders and 16 families were identified. Maximum representatives belong to the order Cypriniformes having 6 species with 44.6% Relative Abundance, followed by Clupeiformes with 2 species with 18.6% Relative Abundance. The beel was heavily infested with aquatic vegetation creating complex environments for the growth of different. The present study indicates that the beel is moderately productive and suitable for commercial aquaculture. The effect of seasonal variations on the assemblage of fish composition is found to be important and it should be considered into account when developing initiatives that will be taken in the future to support the productivity and biodiversity of the wetland.