ESTIMATION OF GROWTH PARAMETERS AND MORTALITY RATES OF KINGFISH (SCOMBEROMORUS COMMERSON) IN THE NORTH PERSIAN GULF (KHUZESTAN PROVINCE)

Length composition data from monthly catches of Scomberomorus commerson landed in Choebdeh and Hendijan fish landing places in Khuzestan province, north Persian Gulf, were collected from 2004 to 2005. We used the data to estimate growth parameters and mortality coefficients of the fish. Response surface analysis produced by the ELEFAN program provided a complete set of Von Bertalanffy growth parameters estimation. We found L¥= 120cm (fork length), K = 0.49 per year and to = -0.11 year for the fish. The length-weight relationship was estimated as W = 0.022 * L2.7575 with r2= 0.978S. Based on the calculated b, we conclude that the fish has an isometric growth pattern. The total, natural and fishing mortality coefficients were estimated as, Z = 1.58, M = 0.58 and F = 1.0, respectively. Exploitation ratio (E) for this species was estimated as 0.63 per year. The E-value indicates that the kingfish in this part of the Persian Gulf has been overexploited. Current fishing pattern in the Khuzestan province shows that 97.07 % of the cumulative length frequency and 78.18 % of the cumulative weight frequency of the landed fish are under standard size. Results of this study indicate that exploitation of kingfish does not follow an optimum trend and if this trend continues, the stock of Scomberomorus commerson in this area will be threatened