Population Parameters of Important Species in Inland Fisheries of Bangladesh

The von Bertalanffy growth model parameters (L sub( infinity ) and K) and mortality coefficients (Z, M and F) were estimated for 12 fish species caught by fishers in five Community-Based Fisheries Management project sites in Bangladesh. The exploitation ratio (E=F/Z) and gear selectivity (L sub(50)) were also estimated for each species. The growth and exploitation parameters obtained were compared with available estimates to evaluate the consistency of the results with current knowledge about the species in the region. The estimates for L sub( infinity ) (7.0 - 24.0 cm) and K (1.077 plus or minus 0.328 year super(-1)) obtained were consistent with those available in literature. Relatively high K (and low L sub( infinity )) values, typical of short-lived tropical fishes, were obtained for nine species. Estimates for Z (1.86 - 6.55) and M (1.22 - 3.06) imply low annual rates of survival and high turnover rates. The estimates for M obtained were consistent with those available in the literature for the 12 species. The exploitation rate was estimated to be between 34 and 53% and the length at first capture was estimated to be approximately 32-56% of L sub( infinity ). The study indicated that the length-at-first-capture/L sub( infinity )seems to be a simple parameter which could be used to make a rapid assessment of the status of the stocks.