Embryos and larvae development observations of Hypsibarbus vernayi

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 45^th 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.