Population dynamic parameters of Thunnus tonggol (Bleeker, ۱۸۵۱) in the Persian Gulf and Oman Sea

Length frequency data of the longtail tuna, Thunnus tonggol collected from October ۲۰۰۶ to September ۲۰۰۷ were analyzed for evaluation of the stock parameters. T. tonggol is mainly caught by gillnet method. Yearly tuna and tuna-like catches in Iran are of the order of ۱۷۴,۲۳۴ mt, close to ۴۶% of which are longtail tuna. The VBG parameters for longtail tuna were: L∞ =۱۳۳.۷۲cm K=۰.۳۵ year−۱.The length –weight relationship was estimated as: W=۰.۰۰۰۰۲ L ۲.۸۳.The instantaneous rates of total mortality (Z) was estimated by using the Powell-Wetherall plot as ۱.۸۲ year−۱. The instantaneous rate of natural mortality was obtained by Pauly equation (M=۰.۴۴ year−۱) and the instantaneous rate of fishing mortality (F) estimated from Z-M=۱.۳۸year−۱.

Keywords:

Growth and mortality parameters , Thunnus tonggol , Persian Gulf , Oman Sea