白甲鱼(Onychostoma sima)早期阶段生长与发育的研究

Study on Growth and Development of Early Postembryonic Stage of Onychostoma sima

在实验室条件下对早期发育阶段(0～33 d)白甲鱼(Onychostoma sima)的生长与发育进行研究。结果表明:水温在(20±1.5)℃时,初孵仔鱼的全长和体质量分别是(10.28±0.05)和(7.79±0.08)mg。白甲鱼仔鱼在孵化后第4天开始摄食,初次摄食率为48%,第6天初次摄食比率达到100%。饥饿不可逆点(PNR)的时间为13.5 d。本研究中还观察到白甲鱼仔鱼PNR点的出现时间与完全饥饿组死亡时间相隔只有2 d,说明白甲鱼仔鱼一旦到达生长的不可逆点,将会在短期内迅速面临死亡,因此,在此阶段须满足白甲鱼仔鱼各种生长条件,保证各个器官都得到充分发育,减少早期因环境不利而造成的死亡或生长停滞现象。

The growth and development of Onychostoma sima under laboratory conditions were studied in postembryonic development stage（0-33 d）.The results showed that the full length and body weight of the hatching larvae were（10.28±0.05） and（7.79±0.08）mg,the larvae had feeding ability for first time on 4th day after hatching;the initial feeding rate was 48 %,the highest feeding rate was 100%on the 6th day.The-point-of-no-return（PNR） was 13.5 days.In this trial,the phenomenon were observed that the difference between PNR and unfed larvae dead time was only two days,indicating that the larvae of Onychostoma sima were dead fast in a short time.So at the larvae stage,all kinds of growth elements were sufficed to ensure the most important apparatus to develop preferentially,and decrease the death and the stagnant growth caused by infaust environment.