Seasonal changes in maturity stage female and hermaphrodite gonad of goldfish Carassius auratus auratus (Linnaeus, 1758)

Abstract

The morphological and histological structure to determine maturity stages of the gonad of the goldfish Carassius auratus auratus were studied Results indicate that the smallest mature female was 91 mm.The monthly Percentage of the gonad different maturity stage and gonadosomatic index showed that the spawing activity were extended from march to September. This was confident with histological study from which the maturing stage were divided to three stage: these were female stage, early transation stage and late transition stage . In female stage, Oogensis progresses through nine phases. Oogonia, Eerly Chromatin-nucleolar Oocytes, late-Chromatin-nucleolar oocytes,perinucleolar- Oocytes , primary vitellogenesis , secondary vitellogenesis, Tertiary Oocyte, haline Oocytes. Atretic Oocyts. At the beginning early chromatin nucleolar Oocytes began degeneration, While late transition stage characterized by rapid proliferation of spermatogenic cells.