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Abstract Length frequency distribution data of blue swimming crab Portunus pelagicus (Linnaeus, 1766) from Suez Gulf waters were based on regular sampling every month from the landings of trawlers operating in the Ataka fishing port-Suez Gulf, and also trammel net boats operating in the Salkhana fishing port-Suez Gulf, during the fishing season 2017/2018.To estimate the growth and mortality parameters for the Portunus pelagicus. The combined length frequency data of P. pelagicus were n= 537. 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 CW∞=23.86 cm (CW) and K =0.89 year-1 (using average of powell-Wetheraal, Shepherd and ELEFAN methods) for pooled data. While males reached CW∞=23.83 cm and K =0.78 year-1. Females estimated CW∞=20.44 cm and K =0.93 year-1. And the t0 value was calculated at (0.27, 0.01 and 0.29) for males, females and pooled data respectively, Examination of population characteristics revealed that Males of Portunus pelagicus grow more than females of the same species. Females of Portunus pelagicus fecundity reached 650000 eggs per mature female .Based on the VBGF growth parameters the total, natural and fishing mortality were calculated at 2.89, 1.09 and 1.8 year-1, respectively for pooled data. The total mortality calculated by taking the average of (Pauly, Jones and Hoeing Methods). While natural mortality calculated by taking the average of (Pauly, Rikhtar, Urisin and Taylor functions). The fishing mortality of pooled data shows greater average than natural mortality which shows that the current status of blue swimming crab is in exploitation state and for extra declare exploitation ratio were estimated for pooled data, males and females (E = 0.62, 0.63, and 0.66 / yr. respectively), these values seem to be over the optimum level of exploitation (Eopt. = 0.50 / yr.). In the light of above results we may assume that the P.pelagicus fishery from Suez Gulf waters are was in overexploited state. It is recommended that some management steps should be taken to maintain the blue swimming crab fishery stock from Suez Gulf waters for the future generations. |