波纹唇鱼(Cheilinus undulatus)的胚胎发育及初孵仔鱼的形态观察

Embryonic Development and Morphologic Observations of Newly-Hatched Cheilinus undulatus Larvae

波纹唇鱼(Cheilinus undulatus)是世界著名的濒危礁栖鱼类,具有特殊的生物学特性和较高的经济价值。本研究对波纹唇鱼的胚胎发育及初孵仔鱼的形态进行了观察,将其全过程划分为胚盘形成、卵裂、囊胚、原肠?神经胚、器官发生和孵化6个阶段,共26个发育时期。波纹唇鱼的受精卵为无色透明的浮性卵,圆球形,卵径为(635.6±50.0)μm,具油球1个,其卵径显著小于多数海水鱼类。在水温27.7–29.0℃、盐度30的条件下,受精卵历时15 h 30 min孵出仔鱼。初孵仔鱼全长为(1305.5±50.0)μm,卵黄囊前部长于仔鱼头部,且油球位于卵黄囊的最前端。结果显示,波纹唇鱼卵子较小,胚胎发育较快,其较快的胚胎发育与较小的初孵仔鱼可能是导致胚后发育阶段死亡率较高的重要原因。

{Abstract}： Thehumphead wrasse, Cheilinus undulatus, is one of the most famous endangered reef fish in the world. As a social hermaphroditic fish, it has special biological characteristics and high economic value. In this study, we observed the embryonic development ofC. undulatusandanalyzed its features under a microscopy. Six periods, including zygote, cleavage, blastula, gastrula-neural, organogenesis, and hatching, were divided during the embryonic development ofC. undulatus. These 6 periods include 26 stages, including zygote, blastoderm formation, multi-cell, morula, and tail bud stageetc. The results showed thatC. undulatus had a float, transparent, spherical egg with a big oil globule. The diameter （635.6±50.0）μm of the egg was obviously shorter than eggs of many marine fishes. The neural plate appeared in the mid to late gastrula stage, and the embryonic development ofC. undulatus was remarkably quicker than other fishes under the same condition. The fertilized eggs were hatched after 15.5 h at water temperature of 27.7-29.0℃and salinity of 30. The total length of newly-hatched larvae were （1305.5±50.0）μm with an elliptic large yolk sac over the head and a shining oil globule in the front of it. These results suggest that the embryo development of C. undulatus was faster than many other fishes due to smaller egg. The special embryonic development features of thehumphead wrasse may cause high mortality in the post embryonic stage.