Daily Growth Increments in the Larval Otolith of the Japanese Eel, Anguilla japonica
Daily Growth Increments in the Larval Otolith of the Japanese Eel, Anguilla japonica
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日本鳗鱼幼虫耳石的每日生长增量
DOI：
10.11369/jji1950.35.440
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
H. Yamakawa
中科院分区：
文献类型：
--
作者：
A. Umezawa;K. Tsukamoto;O. Tabeta;H. Yamakawa
对人工孵化的日本鳗幼鱼耳石的早期形成进行了研究。刚孵化的仔鱼有一对扁平的近椭圆形箭形，平均直径8.3μm。射手座的直径随着年龄的增长呈线性增长。在孵化时，箭尾鱼没有观察到生长的增长，而2日龄、4日龄和6日龄的幼虫分别平均增长了2.1、3.6和6.0。增量数(Y)与孵化后日龄(X)呈密切的线性关系(Y=0.96X+0.06，r=0.913，n=40)，提示每日都有矢状增量的沉积。在95%的野外捕获的鳗鱼中，在射手座的核周围发现了一个直径为6-12μm的明显的暗环。这似乎是一张孵化时存放的“孵化支票”，因为它的直径与刚孵化的幼虫的射手座直径大致相同。可能，孵化检查外的增量数代表鱼的年龄(以天为单位)。
Early formation of otolith was studied on artificially hatched larvae of the Japanese eel,Anguilla japonica. Newly hatched larvae had a pair of sagittae which were flat and subelliptical with 8.3 μm in mean diameter. The diameter of the sagitta increased linearly with age. No growth increments were observed in the sagitta at hatching, while larvae which were 2, 4 and 6 days old had on average 2.1, 3.6 and 6.0 increments, respectively. The number of the increments (Y) and the age in days after hatching (X) showed a close linear relationship (Y=0.96X+ 0.06, r = 0.913, n = 40), suggesting daily deposition of sagittal increments. In 95 % of the field-caught elvers of this species, a distinct dark ring (check) with the diameter of 6–12 μm was found around the nucleus of the sagitta. This seems to be a “hatch check” deposited at hatching, since its diameter roughly agreed with that of the sagitta in the newly-hatched larvae. Possibly, the number of the increments outside the hatch check represents the age of the fish in days.