鞍带石斑鱼胚胎发育及仔鱼形态发育、饵料转变的观察研究

Studies on Embryonic Development,Morphological Development and Feed Changeover of Epinephelus lanceolatus Larva

对鞍带石斑鱼(Epinephelus lanceolatus)的胚胎发育、仔鱼形态发育及饵料转变进行了观察研究,详细描述了胚胎发育各个时期的形态特征。鞍带石斑鱼受精卵在水温(29±0.5)℃、静水微充气、盐度30(即30‰)的孵化条件下,经过18h30min仔鱼开始孵化出膜。胚胎发育过程分为卵裂期、囊胚期、原肠胚期、神经胚期和器官形成期。在水温25.0～30.0℃和盐度33.0～35.0(即(33.0～35.0)‰,全文中的盐度单位都为‰,略去不写)的室外水泥池进行初孵仔鱼的培育试验,仔鱼在孵化出膜后72h开口摄食。4日龄仔鱼的卵黄囊几乎完全消失,开始摄食原生动物;从5日龄开始,摄食行为明显,摄食原生动物和小轮虫;8日龄仔鱼逐渐转向摄食桡足类,兼食少量的轮虫;13日龄后,仔鱼的饵料以桡足类成体为主,摄食量大;经过21天培育进入稚鱼期。

Embryonic development, morphological development and feed changeover of Epinephelus lanceolatus larva were observed and studied in this paper, and the features of every embryonic developmental stage and morphological features of larva were described detailedly. The results shown that the time for the giant grouper embryonic development is 18h 30 min in the static water with temperature 29±0.5℃, aerating slightly, salinity 30.0. Based on the experimental data, the embryonic development of the giant grouper can be divided into five stages, namely cleavage stage, blastula stage, gastrula stage, nerve stage as well as organogenesis stage. Newly hatched larva were nurtured in outdoor tanks under the conditions with temperature 25.0-30.0℃ and salinity 33.0-35.0. 72 hours after hatching, the yolk-sac was almost disappeared and the larva started to eat protozoa. From the 5th day, the larva fed on protozoa and small rotifers. From 8 days, larva start to eat copepod nauplius, also with few rotifers. After 13 days of hatching, larva eat mainly on copepod and dietary intake increased. The larva developed into juveniles 21days after hatching.