Natural gonadal compartmentalizing of economical important Hemiramphus far from Thailand by visual observation and histological technique

Abstract

In order to increase knowledge on the reproductive biology of Hemiramphus far as the most economical marine fish, the gonadal structure and gametogenic differentiation of this fish were clearly described by visual observation and histological technique. Based on the visual observation in female fish, the typical morphology of the mature ovary was a paired cystovarian type. It showed the yellow-orange color ova with containing the differentiating stage of oocytes. The ovary of this fish developed synchronous oocyte. At the same time, the classification of the oogenic stages was divided into three distinct phases; primary growth phase (perinucleolar and oil droplet and cortical alveolar stages), secondary growth phase (early secondary growth step, late secondary growth step, and full-grown oocyte step stages) and post-ovulatory phase. In particular, the post-ovulatory stage was found indicating the spawning season at this time. In male fish, the mature testis was histologically designed as the restricted spermatogonial type, in which the developing spermatogenetic stages could be classified into three phases; spermatogonial, spermatocyte and spermiogenetic phases. Although the gonad histological results from this study provided a comprehensive pattern of the reproduction, they are relevant to further observations (reproductive cycle and endocrinology) with H. far as well as with Hemiramphidae.

Keywords

• germ cells
• Hemiramphidae
• histology
• reproductive system