Investigation population dynamic of Arius thalassinus in the east of Qeshm Island (the Persian Gulf)

This study was conducted on population dynamics of giant sea cat fish, Arius thalassinus in the Eastern coastal of Qeshm Island, Persian Gulf. Age of fish was estimated by second pectoral radial bone. Growth was estimated by the Von Bertalanfy growth model. The results showed that growth parameters for A. thalassinus were: Lt=90.36{1-exp [-0.17(t-0.07)]} and Lt=101.89{1-exp[-0.20(t- 0.41)]} for female with a growth performance index of ǿ=3.423. The meane lenght of A. thalassinus specimens caught in the study area 47.63±13.64 cm for males and 52.17±12.4 for females. The weight meanes for males and females were 1.34±1.10 and 1.67±1.27 respectively. The b was 2.99 and 2.20 for male and female that shows growth in A. thalassinus is allometric. Sex ratio during the study was 1:1.77 (χ2=1.75, P<0.05). The instantaneous natural mortality coefficient was 0.36 and 0.33 in female and male. According to the results of this study. A. thalassinus have low growth rate, high L∞ and common recruitment pattern the same of tropical fishes.