实验室饲养的重口裂腹鱼仔鱼的形态发育与生长

观察了在实验室内(15.0±0.2)℃水温条件下培育的重口裂腹鱼仔鱼的形态发育过程。结果显示,初孵仔鱼全长(10.81±0.37)mm,肌节52～58对,多数55对,身体透明,眼褐色,口凹形成,2对鳃弓雏形出现,胸鳍原基突出于居维氏管外的体侧;出膜后第3d仔鱼在头背部出现黑色素,第6d时在躯体上部以及肠道和卵黄囊之间分布浓密的黑色素;出膜后第13d开口摄食,第17d仔鱼全长达到(15.86±0.43)mm,卵黄吸收完全并彻底依赖于外源性营养;鳔一室和鳔二室出现在出膜后第11d和24d;仔鱼全长为(15.79±0.37)mm时尾椎开始上翘;背鳍、臀鳍和腹鳍分别于出膜后第28d、37d和70d形成。卵黄囊体积VY(mm3)与出膜后天数D(days)的最佳关系式为:VY=-0.0061D3+0.1935D2-2.3856D+14.489(R2=0.9825);体高、眼径、头长和肛后长与孵出后天数呈明显的幂函数关系,而全长呈显著的二项式生长关系。

Morphological Development and Growth of Laboratory-reared Larval Schizothorax davidi(Sauvage)

This study describes the morphological development and growth of laboratory-raised Schizothorax davidi(Sauvage) larvae at the experimental temperature of(15.0±0.2) ℃.Newly hatched larvae were(10.81±0.37) mm in total length(TL) with 52～58 myomeres.They were transparent but showed brownish eye pigment.The rudiments of the pectoral fins protruded from the body trunk behind the base of the cuvierian ducts and two pairs gill arches were easily observed.The anterior region of the oral cavity was formed.Within 3 days after being hatched,larvae had small melanophores scattering over their heads.By the 6th day larvae possessed intensive melanophores on the ventral part of the gut,and the ventral and dorsal sides of the caudal area.By day 13 larvae began to eat.Within 17 days after being hatched,the larvae had attained(15.86±0.43) mm TL and had completely consumed their yolk.One-chamber air bladder and two-chambers ones occurred at 11 and 24 days after being hatched,respectively.Notochord flexion began at(15.79±0.37) mm TL.Formation of dorsal,anal and ventral fins of larvae appeared around day 28,37 and 70.The optimal regression equation between volumes of yolk sac VY(mm3) and days after hatching D(d) was described as:VY=-0.0061D3+0.1935D2-2.3856D+14.489(R2=0.9825).Highly significant power function correlated appear between days after hatching and body height,eye diameter,head length,while postanal length,however,positively binomial relationships between days after hatching and total length.