اثر سن بر عملكرد توليد مثلي مولدين ماده قزل آلاي رنگين كمان (Oncorhynchus mykiss Walbaum, 1972)

Effect of age on reproductive performance in female Rainbow trout broods (Oncorhynchus mykiss Walbaum, 1972)

Rainbow trout is the most important species of rearing cold water fish in Iran. One of the main problems in itʹs culture is artificial propagation and production of alevins. In the propagation process of rainbow trout, different factors involved in quality and quantity of female broods and their eggs. For these reasons at propagation season in 2008, the effect of reproductive performance of female broods on fertilization , eyed stage , hatching and survival rates until absorption of yolk sack stage in Rainbow trout. For this study, 3 groups of broods (3, 4 and 5 years old) were fertilized with males was studied. The results showed that, 5 years old female have maximum rate of body weight (1764.3 gr), total length (53.03 cm), eggs weight (251 gr) and fecundity rate (3536.6 eggs). There were significant difference in fertilization rate, number of fertilized eggs, survival rate to eyed stage and hatching rate among treatments (p<0.05). The present study showed that the produced eggs from fertilization of 5 years old female eggs and male mixed milt have maximum rate in fertilization percentage(97.2%), survival percentage until eyed egg stage (96.52%), hatching percentage (94.50%), survival percentage until absorption of yolk sack stage(93.3%) and number of active alevins (2907.8 larva).