骨唇黄河鱼耳石早期形态发育和轮纹特征研究

STUDY ON THE OTOLITH DEVELOPMENT AND THE FORMATION OF INCREMENTS IN LARVAE AND JUVENILEOF CHUANCHIA LABIOSA

  • 摘要: 研究了骨唇黄河鱼仔稚鱼耳石在实验室养殖条件下的发育过程和生长特点,确证了轮纹沉积规律。结果表明,在14.0-17.8℃孵化条件下,微耳石和矢耳石在受精后96h 30min出现,星耳石在出膜后第16天出现。仔稚鱼生长过程中矢耳石形状变化较大,由出膜时的圆形发育到稳定时的箭矢状。微耳石由近圆形发育成贻贝形,其中心核位置随发育明显偏移。星耳石形状不规则,从出现时的心形发育成为星芒状。微耳石和矢耳石在前后轴方向上后区的生长快于前区(P0.05);在背腹轴方向上,微耳石腹区的生长快于背区(P0.05),矢耳石背区的生长快于腹区(P0.05),两对耳石的前后区半径之和与全长均呈线性相关。微耳石和矢耳石的第1个轮纹均在出膜后第2天形成,新增的轮纹数(微耳石IL,矢耳石IS)与出膜后的天数(D)表现出显著的线性相关,方程分别为: IL=0.9911D-1.0008(R2=0.9971,n=220,P0.001)和IS=0.9925D-0.10873(R2=0.9919,n=161,P0.001),方程的斜率与1均无显著差异(P0.05),表明两对耳石轮纹沉积均呈日周期性,生长轮为日轮。研究结果丰富了骨唇黄河鱼的发育生物学资料,可为研究其自然种群早期生活史提供参考。

     

    Abstract: Daily observations were made on the morphological development and the growth in increments of the otolith in larvae and juvenile of Chuanchia labiosa in rearing conditions. The sagitta and the lapillus appeared at 96h and 30min after the fertilization, and the asteriscus first appeared at 16 days post hatching. The shape of the sagitta was rounded at hatching and gradually changed into long elliptical with a long pointy posterior in the end. The lapillus was also rounded at hatching, and changed into a mussel shape at the end of the experiment. Compared to the sagitta and the lapillus, the shape of the asteriscus remained mussel-like and was relatively stable during the development. We compared the data of the radius of the dorsal, ventral, anterior and posterior areas in the sagitta and the lapillus. It showed that in the lapillus the growth of the posterior was faster than that of the anterior (P0.05), and the ventral grew faster than the dorsal (P0.05); in the contrast the dorsal grew faster than the ventral in the sagitta (P0.05). The combined length of the radius of the anterior and the posterior of the sagitta was linearly related to the total length of the larvae and the juvenile, and the same was observed in the lapillus. The first increment on the sagitta and the lapillus appeared on the second day post hatching and from then on there was one new increment formed every day. The number of increments on the lapillus (IL) and the sagitta (IS) showed a linear relationship with the number of days post hatching (D), with the equations of IL=0.9911D-1.0008 (R2=0.9971, n=220, P0.001) and IS=0.9925D-0.10873 (R2=0.9919, n=161, P0.001), respectively. The slopes of the equations were statistically close to 1.0 (P0.05). These results suggested that the number of the otolith increments increased by 1 on a daily basis. Our study contributed to the understanding in the development of C. labiosa, as well as in its early life history in the natural environment.

     

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