闽南—台湾浅滩渔场金色小沙丁鱼卵巢发育的组织学研究

A Study on ovary development of Sardinella aurita in Minnan-Taiwan Shoal Fishing Ground

闽南-台湾浅滩渔场金色小沙丁鱼（Sardinellaaurita）的卵母细胞发育可分为6个时相。第2时相中期卵母细胞胞质分为内外两层，印母细胞中印黄物质的发生和积累情况为：卵黄泡先出现于印膜内缘区域，层数逐渐增多；印黄颗粒出现于印黄泡之间，逐渐向核区扩展；最后出现的是油滴，它位于核周区域。产卵后未排出的第3、4、5时相印母细胞的退化主要是靠颗粒细胞的吞噬作用进行的。根据成熟系数和组织学结果判断闽南-台湾浅滩渔场的金色小沙丁鱼属多次产卵类型，每年至少产卵2次，4～6月为产卵盛期。

The development of ovary and oocytes and the changes of gonadosomatic index(GSI) ofSardinella aurita in Minnan-Taiwan Shoal Fishing Ground are studied annually. The oogen-esis can be divided into six phases. In the middle of the second phase,cytoplasm is composedof two layers, the inner and the outer layers. In the oocytes of the fish, three kinds ofvitelline elements, in, yolk vesicles, yolk globules and oil droplets appear at this stage. Theyolk vesicles first appear at the edge of the membrane of oocytes- with the development of theoocytes .they turn into several layers. At the end of the development,they are depressed bythe yolk globules, which lie between the yolk vesicdes. The yolk globules extend toward thenucleus gradually. The oil droplets lie in the periphery of the nucleus.The yolk of degenerat-ing oocytes is phagocytized by granulosa cell. While the thecal layer does not proliferate orinvade the oocyte by remaining as a thin layer covering the granulosa cell. The study indi-cates that the females may spawn at least twice during a slngle spawnlng season. The rea-sons are as follows: 1)The development of oocytes is asyncronous type and the mature o-varies contain groups of oocytes at various maturation stages at the same time; 2)The annualvariation of the gonadosometic index (GSI)has two peaks;3)A protracted spawning seasonoccurrs from March to July. The peak spawning activity occurrs from April to June.