大鳞高须鱼胚胎及仔鱼发育观察

Embryos and larvae development observations of Hypsibarbus vernayi

  • 摘要: 大鳞高须鱼 (Hypsibarbus vernayi) 是澜沧江下游的土著鱼类和重要经济鱼类,现为偶见种。为实现大鳞高须鱼的人工繁育和规模化生产,并为其种群资源的保护和开发利用提供指导,通过人工催产获得大鳞高须鱼受精卵,系统观察并记录了其胚胎及仔鱼发育时序与形态特征。结果表明,大鳞高须鱼产漂流性卵,卵呈圆形、灰色,成熟卵子直径为 (0.7±0.1) mm,受精卵吸水膨胀后卵径增至 (3.5±0.1) mm。在水温26~28 ℃条件下,胚胎发育历时16 h 45 min,孵化积温为460.22 h·℃,经历胚盘期、卵裂期、囊胚期、原肠胚期、神经胚期、胚孔封闭期、器官形成期和破膜期共8 个阶段,33 个时期。初孵仔鱼全长为 (2.9±0.1) mm,通体透明,心脏位于卵黄囊前方,可观察到明显心跳及无色透明血液流动,眼无黑色素沉积,卵黄囊体积较小。仔鱼出膜36 h后开始摄食,45 h后卵黄囊完全吸收。研究发现,大鳞高须鱼易受饥饿胁迫,在其培育过程中需及时提供充足的开口饵料,以提高苗种成活率。

     

    Abstract: Hypsibarbus vernayi, an occasional species now, is an indigenous fish and economically important fish in the lower reaches of the Lancang River. In order to realize its artificial breeding and large-scale production of H. vernayi, and to provide guidance for the protection, development and utilization of the resources, we obtained its fertilized eggs by artificial oxytocin. Then we observed and recorded the developmental sequence and characteristics of the embryos and larvae. The results show that H. vernayi produced drifting eggs which were round and gray. The mature egg diameter was (0.7±0.1) mm, and the fertilized egg diameter was (3.5±0.1) mm after water absorption expansion. At the water temperature of 26–28 ℃, the embryo development process lasted for 16 h 45 min, and the accumulated temperature was 460.22 ℃·h, which experienced 7 stages including 33periods (Blastoderm stage, cleavage stage, blastula stage, gastrula stage, neurula stage, closure of blastopore stage, organogenesis stage and hatching stage). The newly hatched larvae were transparent with a total length of (2.9±0.1) mm, and the heart waslocated in front of the yolk sac, where obvious heartbeat could be observed. Colorless and transparent blood flew without melanindeposition, and the yolk sac volume was small. The feeding started 36 h after the hatching. The yolk sac absorbed completely at 45th hour. Since H. vernayi is vulnerable to starvation stress, it is needed to provide adequate opening bait to improve the seedling survival rate during larvae breeding.

     

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