白斑狗鱼胚胎和卵黄囊期仔鱼的发育

Development of embryo and yolk-sac stage larva of white spot pike, Esox lucius

连续观察了7批白斑狗鱼胚胎及卵黄囊期仔鱼的发育状况并进行比较分析。结果显示:(1)白斑狗鱼在水温7～13℃时,胚胎期需248h,有效积温100～120℃·d;水温11～13℃时,卵黄囊期需10d,有效积温110～130℃·d。(2)白斑狗鱼出膜前期可见眼球色素、出膜期可见体色素。白斑狗鱼胚胎卵黄囊表面有许多小油滴分布。白斑狗鱼出膜前期胚体头尾绕卵黄囊超过一周。(3)白斑狗鱼胚胎颜色随着发育进程由起始的淡黄色转为绿黄色,最终出膜前转变为棕褐色。胚胎发育不同步,仔鱼出膜数百分比第1天、第2天、第3天、第4天分别是20%、50%、20%、10%,为避免互相残食,对分批出膜的仔鱼即使是同批受精卵也应分开饲养。

The development of embryo and yolk-sac stage larva of white spot pike(Esox lucius) was studied. (1) At 7-13 ℃, it needs 248h from fertilizing to hatching stage, and the accumulative temperature of 100-120 ℃·d is necessary. At 11-13 ℃, it needs 10 d from hatching stage to yolk-sac absorbed stage, and the accumulative temperature of 110-130 ℃·d is necessary. (2) In white spot pike, eye color appeared in pre-hatching stage, and body color appeared in hatching stage. There are many small oil drips on the surface of yolk-sac of white spot pike. In pre-hatching stage, head and tail of embryo of white spot pike are close each other or partly overlap. (3) Color of embryo of white spot pike changes gradually from light-yellow in early stage to green-yellow in middle stage, and finally to brown in pre-hatching stage. Development of embryos of white spot pike is not synchronizing. on 1st, 2nd, 3rd and 4th day, the percentages of hatched larvae are 20%, 50%, 20% and 10% respectively. In order to avoid preying on each other, white spot pike larva, hatched on different days, should be farmed separately.