تغييرات هورمونهاي جنسي د ر طي مراحل رشد تخمد ان ماهي Epinephelus coioides د ر خليج فارس

Interaction of ovarian development and gondal hormons in Epinephelus coioides of Presian Gulf

Epinephelus coioides (family Serranidae) is a protogynous fish. This species is one of the most important fishes in food chain of marine proteins of Persian Gulf. In this study, Monthly samples of Epinephelus coioides were examined during 17 months from may 2001 to September 2002 in Persian Gulf. Blood samples and oocytes at all stages of development were taken from this species. The hormones have assayed and also different stages of gonadal maturation, from the histological point of view were studied by light microscope. The results indicated that changes in serum levels of gonadal estradiol were correlated with ovarian development. Serum 17 (3 estradiol concentration increased in April and reached their highest levels (1.482 ng/ml. p<0.01) in ripe females, whose gonads contained both cortical alveoli and vitellogenic oocytes during the spawning season. 17(3 estradiol level was also correlated with gonadosomatic index(GSI). and the peak of GSI occurred in May. Testosterone peaked in female during vitellogenesis and maturation (1.045 ng/ml. p<0.01). Plasma concentration of 17- 205P were significantly elevated in female with ovaries undergoing final oocyte maturation (FOM) and to have high potency to induce maturation. Regarding to the results of this research, it seems that the period of spawning in Epinephelus coioides is in May - June and the aquaculture procedure of this species could be performed in the above mentioned periods.