A study of changes in plasma testosterone in Abudefdus vaigiensis at the northern coast of Qeshm Island, Persian Gulf

Although sex steroids play an important role in many physiological processes including reproduction in vertebrates¡ there is a few information about the effects of these hormones in coral-reef fish reproduction. Determination of fluctuation of these hormones would be very useful in reproductive studies. In this study¡ 120 specimens Abudefduf vaigiensis including 47 females and 34 males were captured by rod and line from the northern coast of Gheshm Island¡ Persian Gulf. The plasma levels of testosterone during the gonadal development were determined through ELISA method. The mean of testosterone were 2.59± 0.78 in autumn (min 2.57 in July¡ max 3.24 in August) and 2.30 ± 1.57 ng/ml in winter (min 1.43 in November¡ max 2.97 in Desember) for females¡ which the values of November were significantly less than July. Also in August and August values were significantly more than September. The testosterone mean in males were 2.28± 0.65 in autumn (min 2.01 in September¡ max 2.67 in August) and 1.90 ± 0.88 ng/ml in winter (min 1.57 in November¡ max 2.10 in Desember). The mean values of November were significantly less than the others month. The results showed that the value of testosterone due to its role in gonadal development during vitellogenesis¡ in different months has been significantly changed. The levels of this steroid increased as in August the high level of this hormone is measured in both sexes.