瓣结鱼的胚胎及幼鱼发育

The embryonic and larval development of Tor brevifilis brevifilis

首次记述了瓣结鱼的早期发育过程 ,对其胚胎及幼鱼发育各期特征先后进行了 3次较为仔细的观察 ,并记述了胚胎发育的积温、累积度时值以及从孵化到 10 5d的幼鱼的生长数据。成熟卵直径 1.7～ 1.9mm ,受精卵吸水膨胀后 ,外膜径达 2 .5～ 2 .7mm ,具粘性。在水温 2 0 .5～ 2 3.0℃条件下 ,受精卵历时 71h 7min孵化 ,初孵仔鱼平均全长 6 .6mm ,经 6 5～ 72d ,幼鱼发育基本完成。对瓣结鱼胚胎发育的下限温度及早期发育作了探讨。

The present paper deals with the early development of Tor brevifilis brevifilis. The development characters of embryos and larvae in every stage have been carefully observed for three times. The experiment obtained the sum of heat and the product of effective temperature by time in all stages of embryonic development. The growth digits in 105 days during larval development were measured. The fertilized eggs are sticky, their diameters are 1.7～1.9mm and 2.5～2.7mm after being expanded in water. While the water temperature is 20.5 ～23.0℃, the whole process of embryonic development lasted for 71 hours and 7 minutes. The mean length of newly hatched larva is 6.6mm. After 65 to 72 days, the development of larvae has nearly completed. The desired lowest temperature during embryonic development and several obvious characters in its total early development have been discussed.