Population dynamics of Vimba vimba persa in Iranian waters of the Caspian Sea
The population dynamic parameters of Vimba vimba persa (Pallas, 1811) were investigated from 994 specimens collected in the Iranian waters of the Caspian Sea from October 2008 to September 2009. Fork length ranged from 9.5 to 23.4 cm. Von Bertalanffy growth parameters from size-at-age data are: L∞ = 26.1 cm, K = 0.28 yr-1, to = -0.65. The length-weight relationship coefficient b for males (b = 3.128) was higher than that for females (b = 2.971). The oldest fish was 5 years old. Sex ratio was 1:1.35 (n = 935) with females predominating. Using the catch curve method, the instantaneous coefficient of total mortality Z was estimated as 1.07 yr-1. The instantaneous coefficient of natural and fishing mortality M and F were 0.58 and 0.49 yr-1, respectively. The current exploitation ratio E = 0.46 indicated that the population seems to be highly exploited, and probably not at a sustainable level.