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通过显微照相系统对洛氏胚胎及仔鱼发育进行观察,较为详细描述洛氏早期个体发育模式。结果表明,在水温为14.0~14.5℃条件下,洛氏受精卵完成胚胎期发育所需有效积温为2 005.02℃·h,整个胚胎发育过程可分4个阶段,18个发育分期。洛氏卵裂前、卵裂、囊胚和器官形成4个阶段分别历时2.5、5.5、24和122 h。刚破膜的仔鱼不具游泳能力,全身透明,体循环清晰可见;4 d后卵黄囊期仔鱼口裂明显,头顶部和背部开始沉积黑色素;10 d后,仔鱼开始上浮,卵黄囊基本吸收完全,仔鱼具有游泳能力,鳍条开始不断分化;上浮15 d后仔鱼躯干呈半透明特征,黑色斑点在头顶部和背部大量沉积,胸鳍、背鳍与臀鳍基本分化完毕。
The development of embryos and larvae of S. roxbourorus was observed by micrograph system. The development patterns of early instars of L. margarita were described in detail. The results showed that the effective accumulated temperature needed to complete the embryo development was 2.05.02 ℃ · h under the condition of water temperature 14.0 ~ 14.5 ℃. The whole embryo development process could be divided into 4 stages and 18 stages. Pre-Okaroshi cleavage, cleavage, blastocyst and organ formation in four stages lasted 2.5,5.5,24 and 122 h. After 4 days, larvae of larvae of yolk sac were obviously larvae, and melanin began to deposit on the top and back of the larvae. After 10 days, the larvae began to float and the yolk sacs basically absorbed completely. With the ability to swim, the fin began to differentiate. After 15 days of floating, the trunk of the larva was translucent. The black spots were largely deposited on the top and back of the head. The basic differentiation of pectoral, dorsal and anal fin was completed.