大银鱼卵巢的成熟期和产卵类型

ON THE MATURITY OF THE FEMALE GONADS AND THE TYPE OF SPAWNING OF THE ICEFISH

水文对崇明长江口及金山沿海大银鱼的卵巢进行了周年的组织学观察,将大银鱼的卵巢发育划分为六期,还有重复发育的VI—III’期(或III’期)、IV’期和V’期。在生殖时期,至少产二次卵,属多次产卵类型。产卵时间从12月底开始,一直延续到翌年4月。产完卵后鱼体消瘦,不久死亡,寿命仅一年。

This paper presents the cycle of histological changes in the ovary of the icefish(Protosalanx hyalocranius Abbott). Samples were collected from Chongming andJinshan, along the coast of the Dong Hai Sea near Shanghai. The course of ovarian maturation is divided into six stages and a recoveredstage of Ⅵ--Ⅲ′. The ovaries devrelop to Stagu I in April-May;Stage Ⅱ in June-Oct.;Stage Ⅲ in early Nov.; Stage Ⅳ in mid-Dec. The mature rish spawn at the end ofDec. and continue to April of the next year. After the fish released the first batch of eggs, the ovaries regenerate into StageⅥ-Ⅲ′, which continue to develop rapidly into Stage Ⅳ′About half a month laterthe ovaries develop into stage Ⅴ′and are ready for a second spawning. The resulte indicate that this species releases at least fwo batches of eggs during itsreproductive period. It is obvious that the fish is a multiple spawning type After thelast-spawning the parent fish die off. The lifespan of icefish is only one year.