卵形鲳鲹的早期胚胎发育

Early embryonic development in Trachinotus ovatus

对人工繁殖的卵形鲳鳆（Trachinotus ovatus）受精卵的胚胎发育过程进行了连续观察。受精卵由人工养殖的性成熟亲鱼，经人工催产、自然产卵受精获得。卵形鲳鲮的成熟卵呈圆形，平均卵径为967．8μm。受精卵在水温18～21℃、盐度31的条件下，胚胎发育历时41h27min后孵出仔鱼。胚胎发育为盘状卵裂，胚体后期的发育速度较快；仔鱼脱膜孵化的速度非常快，基本上在1min内就可以完成。初孵仔鱼平均全长为1．548mm，卵黄囊较大。

The embryo development of Trachinotus ovatus was observed consecutively. The fertilized eggs were obtained by artificial induction of hormone-injecting in mature T. ovatus. The fully mature egg was spherical shape, floating, transparent and 967.8μin in average diameter with a single oil globule. The blastodisk appeared at 45 minutes and at 1 hour 10 minutes, the first cleavage occurred after fertilization. At 4 hours 45 minutes, blastula stage appeared and then gastrula stage at 10 hours 5 minutes. Embryo formation formed and Kupffer＇s vesicle occurred at 25 hours 30 minutes. The hatching time was about 41 hours and 27 minutes after fertilization when the first larva was hatched at 18 -21℃ and salinity 31. Newly hatched larvae had a total length of 1.548 mm and a larger yolk sac.