Stock assessment of blue swimming crab portunus pelagicus (linnaeus,1758) from pakistani waters (Northern,Arabian Sea)

Length frequency distribution data of blue swimming crab portunus pelagicus (linnaeus,1766) from pakistani waters were used to estimate the growth and mortality parameters during 2015. the combined length frequency data of p. pelagicus were n= 1459. the data were measured in carapace width (cw) in cm. the analyses were based on fisat stock assessment computer software package. the von bertalanffy growth function parameters cw8=17.85 cm (cw) and k =1.700 year-1 (using elefan method) and the t0 value was calculated at-0.975. based on the vbgf growth parameters the total,natural and fishing mortality were calculated at 4.60,1.684 and 2.915 year-1,respectively. the yield per recruit described that when tc was assumed to be 2,fmax was estimated 2.2 and f0.1 as 3 and when tc was assumed to be 1,fmax as estimated at 2.15 and f0.1 at 3. currently we assume that the age of fish tc at first capture is about 1 year and fcurrent was 2.915,therefore fcurrent was greater than f0.1 and fmax which shows that the current status of blue swimming crab is in overexploitation state. furthermore,when using guland (1971) biological reference points fopt was equal to m (1.685) the current fishing mortality rate is 2.915 was greater than biological reference point. the exploitation rate (e) was calculated at 0.633. in the light of above results we may assume that the p. pelagicus fishery from pakistani waters are was in overexploited state. we may recommend that some management steps should be taken to maintain the blue swimming crab fishery stock from pakistani waters for the future. © copyright 2016 zoological society of pakistan.