宽鳍鱲仔稚鱼发育

Development of Larvae and Juvenile of Zacco platypus

经干法授精及在人工培育条件下观察了宽鳍鱲仔稚鱼发育过程及特征。结果表明,宽鳍鱲受精卵平均直径为2.11±0.11 mm,在水温26~27℃条件下,宽鳍鱲仔稚鱼发育历时25 d。初孵仔鱼全长为5.29±0.14 mm,卵黄囊长为4.01±0.18 mm,孵化后120 h卵黄囊消失,营外源性营养;孵化后14 d仔鱼开始出现二室鳔及背鳍;孵化后17 d仔鱼各鳍鳍条发育基本完成;孵化后19 d仔鱼开始出现鳞片,进入稚鱼期;孵化后25 d稚鱼全长16.54±0.24 mm,全身鳞被,外部形态与成鱼基本相似,进入幼鱼期;宽鳍鱲仔稚鱼全长与日龄的线性方程为L=0.3954 t+5.9978(R^(2)=0.9819);体重和体长的幂函数方程为W=0.0024 L3.9114(R^(2)=0.9671),幂指数大于3,表明宽鳍鱲仔稚鱼生长为异速生长。

By using dry fertilization and artificial cultivation methods,the development process and characteristics of larvae and juveniles of Zacco platypus were observed.The results showed that the average diameter of the fertilized eggs were 2.11±0.11 mm.When the temperature was 26-27℃,the duration of larval and juvenile development lasted for 25 days.The total length of newly hatched larvae was 5.29±0.14 mm,and the yolk sac length was 4.01±0.18 mm.The yolk sac disappeared 120 h after hatching,the fish began to enter the stage of exogenous nutrition,The two-chamber air bladder and dorsal fin appeared at 14 days after hatching,The fin scales were observed at 19 days after hatching,which means the fish entered the juvenile stage.At 25 days after hatching,the total length of fingerling was 16.54±0.24 mm.The whole body of fingerling was covered with scales at this stage.No difference in the morphological characteristics between fingerling fish and adult fish.The linear equation of length and age of larvae and juveniles is L=0.3954 t+5.9978(R^(2)=0.981).The power function equation of body weight and body length is W=0.0024 L3.9114(R^(2)=0.9671),the power index is high than 3,indicating that the growth of larvae and juveniles of Z.platypus is allometry.