Population structure of banana shrimp, Penaeus merguiensis De Man, 1888 in the Strait of Hormoz, Persian Gulf

Monthly length frequency data of banana shrimp, Penaeus merguiensis were collected from the coastal waters of the north east of the Persian Gulf, from January 2012 to January 2013. Software package FiSAT was used to analyze the length frequency data. Growth parameters, mortalities, exploitation rate and recruitment pattern were estimated from the carapace length in the area. Based on length – weight relationships, the estimated parameter a was 0.0015 for males and females and b was 2.8015 for males and 2.7852 for females. The estimated growth parameters: L∞=39.5 mm, K=1.8 year−1 and t0=-0.08 year−1 for males and L∞=50 mm, K=1.5 year−1 and t0=-0.09 year−1 for females. Longevity was estimated 1.67 and 2.00 years for males and females, respectively. The estimated mortality coefficients, were Z=5.9 (4.89 – 6.92) year−1 (α=0.05), M=2.9 year−1 and F=3.0 year−1   for males and Z=5.7 (4.94–6.37) year−1 (α=0.05), M=2.5 year−1 and F=3.2 year−1 for females. The length at first capture, Lc estimated from the probability of capture routine was 23.3 mm for males and 24.2 mm for females. Sex ratio (M:F=1.1:1) was significantly different to 1:1. The exploitation rates of shrimp were 0.49 and 0.56 for males and females, respectively which could get higher because the survival of spawning stock after the fishing season is related to environmental factors and has less effect on the next year’s biomass. Recruitment was continued throughout the year but with one major peak in July to November.