Histological studies of ovarian development of the Japanese Threadfin Bream, Nemipterus japonicus, in the Northern of Persian Gulf

In the present study, a total of 595 specimens collected monthly in the northern part of Persian Gulf between November 2006 and October 2007 were examined by routine macroscopic and histological techniques. Monthly changes in the gonadosomatic index showed the spawning season extended within 2 peaks, from April- May and September. The maturity stages are morphologically separated according to the changes in size, color and shape of the ovaries. Histologically, the oocytes development described the following stages; immature period (oogonia, early perinucleolus stage and late perinucleolus stage) maturation period (vacuolization stage, yolk granule stage, vitellogenic stage, germinal vesicle migration stage and mature yolk stage). The simultaneous presence of oocytes within ovaries indicated that this species is a batch spawner.