Analysis of fish diversity in relation to limnological characteristics of Chatla floodplain lake of district Cachar, Assam, North East India

This study was carried out to assess the seasonal diversity pattern of fish species based on catch data from landing stations of Chatla floodplain lake in relation to its limnological characteristics over a period one year from March, 2020 to February, 2021. Seasonal patterns in composition and abundance of phytoplankton, zooplankton and fish species were estimated and correlated with water quality parameters. The study also determined the influence of plankton dynamics on the composition and abundance of fish catch. A total of 44 phytoplankton taxa belonging to 5 classes were identified and a total of 31 zooplankton taxa belonging to 4 classes were identified. In terms of abundance, Chlorophyceae was the most dominant phytoplankton class followed by Cyanophyceae and Bacillariophyceae and Cladocera was the most dominant zooplankton class followed by Rotifera and Copepoda. A total of 58 fish species belonging to 41 genera, 25 families and 10 orders were recorded. In terms of composition of fish species, the dominating fish order was Cypriniformes followed by Siluriformes and the dominating fish family was Cyprinadae. In terms of fish yield (or fish catch) also, Cypriniformes dominated over Siluriformes and the fish species Catla catla, Puntius chola, Mystus tengara, Clarius batrachus and Wallago attu were recorded in greater abundance. Shannon-Wiener diversity index was highest in Pre-monsoon and lowest in Monsoon. The value for one-way analysis of variance (ANOVA) for fish species was significant at 5% probability level. From the correlation analysis, it was found that seasonal patterns in the composition and abundance of plankton community are controlled by water quality parameters which, in turn, are controlled by the composition and abundance of fish catch.

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