The article provides an analysis of seasonal changes in the microstructure of the genital glands of the Caspian vimba. To clarify the timing of passage of individual stages of oocyte development and to detail microstructural rearrangements in the egg development cycle it has been necessary to compare the data of the morphoecological observations with those of the microscopic, histological studies. Quantitative and qualitative transformations in fish oocytes are shown, starting from the generative to vegetative stages of development, including the processes of resorption of egg material. After spawning, the fish does not move from the sixth to the third stage, like other cyprinids, but to the second, which contributes to the successful deposition of the first generation of oocytes. Egg laying, resorption of unspawned eggs and previously empty follicles go on in parallel and these processes continue until the end of spawning. It is established that the Caspian vimba, in the conditions of the Caspian Sea, is the-same-time spawning fish. The generation of new portions of oocytes begins after the completion of resorption of all ovarian structures.
Pages: 19 - 25
Date: 28.03.2024