犬齿牙鲆早期形态特征和生长、发育规律

Morphology, Growth and Development in Early Life Time of Paralichthys dentatus

为掌握犬齿牙鲆早期发育的规律,2006年3—6月在实验室利用显微数码摄像系统,通过电脑观察、测定、拍摄犬齿牙鲆仔、稚、幼鱼各期的发育时间及早期的形态特征。犬齿牙鲆室内人工育苗的培育水温19～21℃,S为30,pH为8.2,光照度为500lx左右,饵料依次为经过强化的轮虫、卤虫无节幼体和配合饲料。初孵仔鱼全长2.2～2.5mm,身体透明,至4～5日龄,卵黄囊缩小,开始摄食,6～7日龄卵黄囊吸收完毕进入后仔鱼期;至29日龄全长9.0～9.4mm,冠状幼鳍形成完善,开始进入稚鱼期;43日龄时全长15.0～16.0mm稚鱼右眼完全迁移至左侧,变态完成,营底栖生活进入幼鱼期;幼鱼期鳞被形成完整,基本具有成鱼的外部形态和生活习性。

To learn the regularity in the early stage of summer flounder growth, a system composed of a computer and a digital camera with a mierophotographic lens is used in the laboratory from March to June 2006 to observe and describe the flounder morphological features in its early growth stage respectively cor- responding to the larva, juvenile, and fry phases. The summer flounder breeding is conducted with water temperature between 19 ℃ and 21 ℃, salinity of 30, pH of 8.2, and illuminance about 500 lx. They are fed in turns with rotifer, artemia nauplii, and the fomulum feedings. The full length of the newly hatched larva ranges between 2.20 mm and 2.50 mm and their bodies look tramsparent. 4 or 5 days after they have been hatched, the yolk sac becomes shrunk and the larva begin to feed. 6 or 7 days after hatched, the yolk sac is completely absorbed and the fry phase begins. At the age of 29 days, the full length ranges between 9.00 mm and 9.40 ram, the coromary young fins appear shaped, and the jurenile phase begins. At the age of 43 days, the full length ranges between 15.0 mm and 16.0 ram, the right eyes of juvenile move to the left side, the metamorphism is completed, and the fry phase begins, being ready for benthonic living, Then the squama sheet covers the fry body, which has already had the morphological appearance and the behavious of the adult fish.