عنوان مقاله [English]
Kutum (Rutilus frisii kutum) is one of the economically important fish in the Caspian Sea. To reproduce, these fish migrate from the Caspian Sea to various rivers every year. One of these rivers, which the fish migrate to, is Tajan River. For this reason, millions of newly born kutum, larva cultivated through artificial propagation, are released in the rivers entering the Caspian Sea every year. From among those, male broods have a significant role in the propagation process. For this reason, it seemed necessary to investigate the effect of age on the reproductive performance of male broods in artificial propagation efficiency in Kutum in 2008. For the present study, 3 groups of male broods (3, 4 and 5 years old) were fertilized with female’s broods individually. The results showed that, maximum average spermatocrit percentage (53.67±18.03%) belonged to 3- year- old male broods and maximum average concentration of mail (31.38±12.16×109) belonged to 4-year-old male broods. The results obtained indicated significant differences (P£0.05) in mean fertilization rate and hatching rate. The present study showed that the produced eggs from fertilization of 4- year-old male's milt and female's ova had maximum average of rate in fertilization percentage (95%) and hatching percentage (98.43%). Based on the results of the present study, 4- year-old male broods are the best choice in artificial propagation.