Effect of age on reproductive performance of Kutum, Rutilus frisii (Nordmann, 1840) in Shirood River, southern coast of the Caspian Sea

In this study, we investigated the age-dependent changes in reproductive efficiency of Kutum, Rutilus frisii caught from Shirood River, the Southern Caspian Sea (Mazandaran Province, Iran). Age-dependent reproductive performance of brooders was assayed on two age and sex groups. Results revealed that there were no significant differences in sperm characteristics between age groups. All female characteristics revealed change except relative fecundity between two age groups. The higher fertilization rate (87%) and also survival rate (91%) were found when the 4 year-old males were crossed with 4 year - old females (P 0.05). Our results confirmed the age-dependent changes of reproductive efficiency in Kutum. So that, the cross between 4 year-old males and 4 year - old females could be useful for enhancement of reproductive efficiency in Kutum.