در حوزه جنوب شرق درياي خزر )ACIPENSER PERSICUS( بررسي وضعيت توليد مثلي مولدين تاسماهي ايراني

Reproductive Cinditions of the Iranian sturgeon (Acippenser persicus) in the southeast of the Caspian Sea, Golestan province, Iran

222 prespawning adult Acipencer percius including 178 female and 44 male were sampled in the Shahid MARJANYʹs sturgeon breeding and propagation center for studying the reproductive conditions of the Acipencer persicus in the Southeast of the Caspian Sea during march 2000 - may 2001. In this study age, length and weight frequency of male and female, classification index, percentage of fertilization, effect of temperature on fertilization, the time of female sex ripening, positive feedback of broodstock to injection of pituitary in samples were studied. Female fishes with 19-20 years, 21.1-24 kg body weight and 151-160 cm fork length had the maximum frequency. The range of classification index in brood stock was between 4.3-9.5 that studied in four groups and comparison of groups showed the significant difference in percent of fertilization. The changes of percent fertilization in these groups were surveyed and maximum of fertilization observed in the 7.1-8 groups. The highest fertilization observed in 16.1-18 °c. Increasing the temperature declined the time of female ripening of sexual maturity and positive feedback to pituitary injection. Brood stock ages divided to four group and morphophysiological parameter changes and propagation factors were investigated in these groups. This groups separated by DANCAN test and fork length, body weigut. gonad weight, absolute fecundity, percent of fertilization, condition factor, parameters in u=0.05 showed significant differences. The results of this study showed that with increasing age and reduction of percent of fertilization of brood stock are not suitable for artificial propagation, therefore suggested these broodstock should be used for caviar processing. The condition factors in young age brooders were more than old brooders, too.