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

For study the reproductive physiological differences between fall and spring migrants of Caspian Lamprey (Caspiomyzon wagneri) in the south of Caspian Sea, Shirood River. 15 & 16 fish in autumn and spring were collected. Hormone measured by ELIZA method, and for histological study conventional method and Hematoxilin-eosin staining was performed. In the both spring and autumn season Fishes are in the final reproductive stage, based on Histological studies of gonads, but did not spawning yet. Concentration of testosterone, 17β-estradiol and progesterone hormones of males, in both season, are higher than females, with an exception. Progesterone of females in spring higher than males. Testosterone of males and females is not different between autumn and spring. 17β-estradiol concentrations of females are similar in to two seasons but in autumn males had higher concentrations of 17β-estradiol. Progesterone of males and females was different in both seasons. Generally, the results indicated some reproduction signs of Caspian Lamprey in both fall and spring season.