Chiang Mai Journal of Science

Population parameters of  Polynemus paradiseus were estimated with length-frequency data collected from Estuarine Set Bag Net Fishery of  Chittagong and Cox’s Bazar region in Bangladesh during the period from January 2005 to December 2005. FiSAT software was used to estimate the parameters. The asymptotic total length (L_∞) and growth constant ( K ) were estimated to be 20.48cm and 0.48 1y− respectively. The instantaneous rate of  natural mortality (M ), fishing mortality ( F ) and total mortality ( Z ) were estimated to be as 1.21 y⁻¹ ,3.17 y⁻¹ and 4.38 y⁻¹ respectively. The value of  exploitation rate ( E) was found to be 0.72 which clearly pointed toward over-fishing condition ( E > 0.50 ) for  Polynemus paradiseus in the ESBN fishery of Bangladesh. The recruitment pattern of the species was found continuous all round the year with two peaks one in the months of March-April and another in the months of  August-September. The length-weight relationship was found to be W=0.0087L^2.7398 signifying isometric growth for this species. Virtual population analysis estimated that the maximum numbers of Polynemus paradiseus are caught between 3.5cm to 11.5cm with maximum F value (2.09 y⁻¹ ) in the mid length of 8.5cm. Relative yield per recruit (Y'/R ) and biomass per recruit ( B'/R) suggested that the fishing mortality should be reduced to 1.559 y⁻¹ to obtain maximum sustainable exploitation rate ( E_max = 0.356) for the species P. paradiseus in ESBN fishery of  Bangladesh.