Exploitation patterns and sustainability of four small indigenous fish species of Deepor Beel wetland, Brahmaputra Basin, India

The study investigates variability of population growth, mortality and exploitation pattern of four small indigenous fishes (SIFs), Gudusia chapra, Puntius sophore, Mystus bleekeri, and Heteropneustes fossilis from Deepor Beel, a Ramsar site of north-eastern India. The study was conducted from June 2023 to May 2024, which involved monthly sampling at two stations, analysing a total of 13129 specimens. Data were analysed using FiSAT-II software, to derive species-specific length-weight relationships, growth coefficients, and mortality rates. A positive allometric pattern was observed for P. sophore, while a negative allometric pattern was evident for the other three species, G. chapra, M. bleekeri and H. fossilis. Exploitation rate (E) ranged from optimum (0.48) to moderately high (0.63), with M. bleekeri and H. fossilis being highly exploited. Recruitment pattern varied among species, with peaks occurring at different times of the year from post-monsoon to winter. Current findings underscore the necessity for focused conservation efforts and long-term management strategies for prevention of further decline in populations of these species, which is crucial for maintaining the ecological balance of the beel ecosystem and for sustaining the livelihoods of local communities.