Study of sexual steroids and gonad histology between fall and spring migrants of Caspian Lamprey (Caspiomyzon wagneri), to Shirood River (South of Caspian Sea)

Abstract

For studying the differences in reproductive physiology between fall and spring migrants of Caspian Lamprey (Caspiomyzon wagneri) in the south of Caspian Sea, Shirood River,15 & 16 fish were collected during each season, respectively. Hormones were measured by ELIZA method and for histological study conventional method and Hematoxilin-eosin staining was performed. In both spring and autumn season, based on histological studies of gonads fishes were in the final reproductive stage but have not spawned yet. Concentration of testosterone, 17β-estradiol and progesterone hormones of maleswere higher than in females, with an exception. In spring,progesterone was higher in females. Testosterone of males and females is not differ between autumn and spring. 17β-estradiol concentrations of females were similar in to males in spring but in autumn males had higher concentrations of 17β-estradiol. Progesterone of males and females was different in both seasons. Generally, the results indicated signs of reproductive activity in both fall and spring migrants of Caspian Lamprey.