拉萨裂腹鱼的胚胎及仔稚鱼发育特征

Morphological development of embryos and larvae of Schizothorax waltoni Regan

为探明拉萨裂腹鱼Schizothorax waltoni Regan的早期发育阶段特征和规律,采用显微观察法,对其胚胎及仔鱼发育各时期的形态特征和发育特点进行了研究。结果表明:拉萨裂腹鱼受精卵呈圆形、黄色,卵径为(2.53±0.10)mm;拉萨裂腹鱼胚胎发育水温不宜超过17℃,在(13±1)℃水温下,拉萨裂腹鱼胚胎发育历时225 h 10 min,积温为2838.79 h·℃,根据发育时胚胎的外部形态特征,将胚胎发育的过程划分为受精卵期、胚盘期、卵裂期、囊胚期、原肠期、神经胚期、器官分化期和出膜期8个阶段,33个时期;出膜仔鱼全长为(10.71±0.28)mm,出膜后11 d,仔鱼的鳃、口、胸鳍、尾鳍、鳔、肠道等功能器官先后形成,出膜23 d后卵黄囊消失,全长为(18.35±0.65)mm,出膜70 d时各鳍基本长成,体型和体色接近成鱼,进入幼鱼阶段。研究表明,拉萨裂腹鱼的早期发育特征与其生存的环境具有一定的适应性。

Morphological and developmental characteristics of embryo and larva were observed in Schizothorax waltoni Regan under a light microscope in order to find out the characteristics and rules of early development stage of Schizothorax waltoni Regan.The fertilized eggs of the fish were found to be ovate in shape,yellow in color,and(2.53±0.10)mm in diameter,and not to be incubated at water temperature of over 17℃.The whole embryonic development was divided into 8 stages and 33 periods,including fertilized egg,blastoderm formation,cleavage,blastula,gastrula,neurula,organogenesis and hatching according to the external morphology and the embryonic development characteristics.The embryos were hatched 225 h 10 min post fertilization,at accumulative temperature of 2838.79 h·℃,and gill,mouth,pectoral fin,caudal fin,swimming bladder,intestinal tract were successively appeared around 11 days post hatching at water temperature of(13±1)℃.The yolk sac of larva was completely exhausted with a total length of(18.35±0.65)mm 23 days post hatching,and all fins of the fish as juvenile stage appeared 70 days post hatching,with the shape and colour of the body closed to adult.The early developmental characteristics of S.waltoni Regan had some adaptability to the habit environment.