鲇胚胎及其仔鱼发育的连续观察

The Continuous Observation of Embryonic and Larval Development of Catfish Silurus asotus

鲇的成熟卵为典型的多黄卵,为不完全盘状卵裂;水温（24±1）℃时,鲇胚胎发育历时35 h,总积温840-875℃.h;脱膜后第1 d,仔鱼口未形成,2日龄口基本形成,口裂宽（B）与日龄（d）的关系可表示为：B=0.0165＋0.3282d（r=0.9756,n=7,P〈0.01,2≤d≤8）;仔鱼孵出后第3 d开口摄食,仔鱼存在混合营养期,持续时间1 d,仔鱼开口摄食的适口食物为枝角类;发育至8日龄时,仔鱼期结束,此时鲇鳍褶消失,鳍条分化,外形与成鱼相似。

The observation shows that the mature eggs of Catfish Silurus asotus are abundant in yolk. The disc cleavage is incomplete. The duration of the Catfish embryonic development was 35 h at water temperature of （24 ± 1 ） ℃ and the total accumulative temperature of 840 - 875 ℃· h. On the 1 st day of hatching, the mouth of the larva was not formed;on the following day, the mouth had been nearly formed. The relationship between the mouth breadth （B） and the age（d） can be expressed： B =0.0165 ＋0. 3282 d （r =0.9756,n =7,P 〈0.01,2 ≤d≤8 ）. The 3 days old larvae were able to feeding. The weaning food of larval Catfish was small cladocera. The larvae had the mixed feeding stage, and the stage lasted 1 day, The newly-hatching larvae developed quickly at 8 days after hatching, and became larval finish.