贝氏高原鳅胚胎和仔鱼的形态发育

通过人工授精获得受精卵，对贝氏高原鳅胚胎和仔鱼的发育过程进行了观察和描述。结果表明，成熟卵淡黄色，卵径较小(直径0.94－1.10mm)，遇水后产生强黏性。在水温9.0－12.8℃下，胚盘在受精后4h20min开始分裂，在19h50min和27h40min时达到囊胚期和原肠期，64h40min胚孔封闭，287h时部分胚胎开始出膜，405h30min全部出膜。初孵仔鱼全长(4.32±0.23)mm，肌节36－38对，眼和躯干部黑色素细胞明显，胸鳍原基发育良好。出膜后第5天仔鱼体侧和头部出现浓密的感觉芽。到第8天时全长(6.05±0.41)mm，卵黄吸收完全。仔鱼鳔一室和鳔二室分别于出膜后第30天和第50天形成。第55天的仔鱼全长(14.05±1.01)mm，肌节52－53对，体侧出现7－8条黑色素带，各鳍鳍条数目与成鱼基本一致，但仍有少量鳍褶存在。仔鱼的卵黄囊体积减小速度为0.027mm3/d，鱼体长度生长、鱼体长度性状间的比例关系并不相同，其中，肛后长／全长比例随胚后发育逐渐增加，由初出膜时的31%增加到最后的42％左右。

MORPHOLOGICAL DEVELOPMENT OF TRIPLOPHYSA BLEEKERI(SAUVAGE ET DABRY DE THIERSANT, 1874)EMBRYO AND LARVAE

Five mature Triplophysa bleekeri, captured in the middle section of the Qingyijiang River, were selected for artificial fertilization in this study. The fertilized eggs were released into a tank (36. 0 × 28.0×11. Gcm3) under the water temperature of 9.0--12. 8℃. The morphological development of embryos and larva were described and photographed with Leica MZ16A stereomicroseupe. 30 specimens were sampled and observed in intervals of 30min during embryonic stages and 12h after hatching. The results indicated that mature unfertilized eggs were strongly adhesive and spherical with primrose yellow color and contained a relatively small yolk (0.94--1. 10mm in diameter). The first cleavage occurred at 4h20min after fertilization. The blastula and gastrula stages began at 19hS0min and 27h40min, respectively. By 64h40min after fertilization, the blastopore was found to be almost closed. Eye pigment was observed at 160h30min and pectoral fin buds appeared 13h50min later. Hatching occurred at 287h and finished at 405h30min. Newly hatched larvae usually lied on the bottom of the water, which were 4. 32ram in average total length (TL) with myomeres ranging from 36 to 38 pairs. Pigment on the body and eyes appeared clearly and pectoral fin buds were well-developed. Thick sensory buds appeared on both sides of the head and body on the 5 dph (days post hatching). 3 days later, the larvae reached 6.05mm in average TL and consumed their yolk completely. In artificially reared conditions, the larvae were fed with egg vitellus and some species of Tubifex twice a day, all specimens were diverted into constant temperature biochemical incubator after 21 dph. One-chamber air bladder and two-chamber ones formed on the 30 dph and 50 dph, respectively. The larvae had 52 to 53 myomeres when the total length reached 14. 05mm in TL on the 55 dph, moreover, all fin rays reached the same fixed number of adult fish and 7 to 8 dark-brown speckle bands had appeared on the body sides. Yolk sac volumes of the larvae decreased at the average ratio of O. 027mm3/d. Growth in length and body morphometrics varied during different developmental stages. The proportion of post-anal length to total length increased gradually from 31% at the beginning and it stabilized at about 42% finally.