南方大口鲇幼鱼发育的初步研究

ON THE DEVELOPMENT OF LARVA OF SILURUS SOLDATOVI MERIDIONALIS CHEN

  • 摘要: 南方大口鲇的人工孵化鱼苗在11日龄时卵黄消失,转入营外生性营养的仔鱼阶段;23—26日龄仔鱼的主要外部器官分化完毕,转入稚鱼阶段;40—43日龄稚鱼除存在第二下颌须外,其余外形特征与成鱼相似,稚鱼阶段结束. 5月上旬在嘉陵江中采获到的当年幼鱼已发育到稚鱼阶段结束时期的水平;6—7月的当年幼鱼,当体长为151—177毫米时,第二下颌须消失.当年幼鱼体重和体长的关系为: W=e-10.87062L2.74257(N=77,r=0.9952)根据尾形、体色和须的数量的差异,可以区别南方大口鲇和鲇的当年幼鱼.

     

    Abstract: Morphogenesis of the larvae obtained by artificial propapation and those collected from the Jialing River is described in this paper.By 11 daps after hatching, the yolk of larval fish is absorbed fairly well and the larvae begin to ingest food from the environment. By 23—26 days after hatching, the juvenile stage begins as all main external structures of the fish are differentiated. By 40—43 days after hatching, the juveniles have all external features resembling the adult fish except the exsitence of the second lower-jar-barbels, showing the end of the juvenile stage.From May to November, 1984, the young-of-the-year were collected from the Jialing River and their measurable characters are summarized.Fishes collected in May are well-developed juveniles; in June and July, their second lower-jar-barbels disappear when body length attains 151—177 mm. The relationship between body length and weight of young-of-the-year can be expressed as: W=e-10.87062L2.74257(N=77,r=0.9952)By caudal shape, body color and number of barbels, the young-of-the year of S. soldatovi meridionalis can be distinguished from S. asotus.

     

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