东海外海金乌贼角质颚与内壳微结构特征及轮纹判读

Microstructure of Beak and Cuttlebone and Determination of Growth Increments for Sepia esculentas off Coast of East China Sea

【目的】探究金乌贼(Sepia esculenta)的日周期性,以及角质颚和内壳微结构在金乌贼年龄鉴定中的相关关系。【方法】根据2018年9月至2019年3月在东海外海海域(123°-127°E,28.0°-31.5°N)采集金乌贼132尾,对其角质颚、内壳微结构轮纹进行分析判读,并通过线性拟合、差异化比较等非分析角质颚、内壳微结构的轮纹特征,探讨两者轮纹数间及其与胴长的相关关系。【结果】金乌贼角质颚喙部切面生长纹主要分布在头盖区与侧壁区,对称分布于喙部截面纵轴的两侧,其喙部头盖区的背侧生长纹较为完整。角质颚生长纹中还存在标记轮、亚日轮以及其他特殊生长纹结构;金乌贼内壳微结构纵切面的生长纹,从顶端延续到底端,生长纹长度也随之递减。内壳与角质颚生长纹数目为56~137,二者线性相关系数R=0.9471。内壳、角质颚轮纹数与对应样本胴长分别线性相关。【结论】金乌贼角质颚、内壳微结构与日龄线性相关,可作为年龄鉴定材料,但应根据实际情况进行选择。

【Objective】To explore the correlation between the diurnal periodicity and the microstructure of upper beaks and cuttlebones in determining the age of Sepia esculenta.【Method】132 upper beaks and cuttlebones were extracted based on of the data from fishing vessels in the East China Sea(123°–127°E,28°–31.5°N)from September 2018 to March 2019.By embedding and grinding methods,the growth increments was determined.The differences were also studied by stimulation of mathematical model and differentiation comparison.【Result】The growth increments of S.esculenta were mainly distributed in lateral wall and hood region of upper beaks,which were symmetric distribution in the internal rostral axis.The increments in the dorsal region of the beak’s hood were more complete.Besides,checks,sub-day increments and other abnormal structures could be found.The increments of cuttlebones occurred from bottom to top,with the length decreasing.The amount of growth increments on the upper beaks and cuttlebones ranged from 56 to 137.In addition,values of R equaled 0.947(or use 0.95).Number of beak and cuttlebone increments are linearly correlated with the mantle length.【Conclusion】The upper beak had the diurnal periodicity,there was a linear correlation between the cuttlebone and upper beak when referring to the number of growth increments.Based on the results,the upper beaks and cuttlebones are better determining materials that can be used to determine the age and growth.of Sepia esculentas.