Sexual Maturity of the Isaza, Chaenogobius isaza II : Gross Morphology and Histology of the Ovary

概要

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Ovaries of the Isaza are paired organs of the cystovarian type. The morphological changes of the oocyte in the Isaza generally agree with that reported in other teleosts. One of the distinctive features is the bipolarity of the oocyte from as early as the late peri-nucleolus stage. The micropylar cell is already detected at the late peri-nucleolus stage and the yolk nucleus of "Balbiani" is always located at the vegetal pole. The arrangements of the granulosa cells and the adherent filaments also show bipolarity. Oocyte development is group synchronous. Yolk vesicles begin to appear in November. In February the slowly maturing oocytes overtake the preceding oocytes, and almost all mature oocytes are uniform in stage (secondary yolk stage). But in March and thereafter, the oocytes of the yolk-vesicle stage, with more vacuoles than normal ones, increase in number and are absorbed after the spawning period. Half of the 1+ year females which have atretic oocytes in the ovary are regarded as having spawned in the previous year and seem to spawn again. The ovarian oocytes of the immature 0+ year fish remain, at most, at the early peri-nucleolus stage till March.
社団法人日本動物学会の論文
1981-03-25