瓦氏黄颡鱼的胚后发育观察

2002年5~6月,在四川省泸州市、合江县分数批收集到长江野生瓦氏黄颡鱼(Pelteobagrusvachelli)亲本,通过人工催产、人工授精获得受精卵,对其胚后发育过程进行了观察。瓦氏黄颡鱼的胚后发育过程可以分为卵黄囊仔鱼、晚期仔鱼和幼鱼3个阶段。初孵仔鱼淡黄色,肌节40对,平均全长5.2mm。水温20~22℃时,孵出后第3d口张开;第7d开始摄食;第9d卵黄吸尽,此时鱼苗平均全长12mm,卵黄囊仔鱼阶段结束。晚期仔鱼阶段的仔鱼,胸鳍、尾鳍、臀鳍、背鳍、腹鳍先后发育,至鳍褶消失时晚期仔鱼阶段结束。经过30d的生长和发育,进入幼鱼阶段;此时平均全长达37mm,其形态特征和生态习性均与成鱼相似。

Observation on Postembryonic Development of Pelteobagrus vachelli

From May to June in 2002, parent fish of Pelteobagrus vachelli were captured in the upper reaches of Yangtze River at Luzhou and Hejiang of Sichuan Province. Artificial propagations were carried out to obtain fertilized eggs for the observation on the postembryonic development. Postembryonic ontogeny of P. vachelli could be divided into three periods, namely yolk-sac larva, late-stage larva, and juvenile. The newly-hatched larva was pale yellow, lying at the bottom quietly, with 40 pairs of muscle nodes and a mean of 5.2 mm in total length. When water temperature ranged from 20 to 22 degrees of centigrade, mouth formed on the third day after hatching, and the larvae began to feed on the seventh day. Yolk was exhausted on the ninth day, indicating the end of yolk-sac period, while the larva was 12 mm long in average. In late-stage larva period, pectoral fin, caudal fin, anal fin, dorsal fin, and ventral fin developed in sequence. Late-stage larva period ended when fin-folds vanished. After developing and growing for 30 days, it came into the juvenile period. The juvenile was 37 mm in total length, with similar morphological characters and ecological habit to those of adult.