基于形态分析探究鳞头犬牙南极鱼各生活史阶段耳石形态变化

Using shape analysis to inform variation in otolith morphology with life stages of Dissostichus mawsoni

鳞头犬牙南极鱼为南极最为重要的底层鱼类,具有重要的生态作用和极高的商业价值,鱼类耳石形态随着生活史过程的推移有所差异,故耳石形态分析可用于推断鳞头犬牙南极鱼的生活史过程。本研究利用采集自南极罗斯海、阿蒙森海、威德尔海及拉扎列夫海120尾分属4个生活史阶段的鳞头犬牙南极鱼耳石,结合传统测量分析与椭圆傅里叶分析两种形态学研究方法,对其各生活史阶段耳石形态的差异进行研究。结果表明:鳞头犬牙南极鱼各生活史阶段耳石形态存在差异,随着生活史过程的推移,耳石的变化趋势为整体上由轮廓平滑、复杂度较低向轮廓曲折、高度复杂化转变,且纵轴方向增长速度低于横轴方向,翼叶等特征部位变化显著。针对耳石形态的线性判别分析结果显示,椭圆傅里叶分析判别值较高,为85.4%,而传统测量分析判别值较低,为71.9%,表明相较于传统测量分析,椭圆傅里叶分析更具优势。

As the most important domestic fish in the Antarctic Ocean, Antarctic toothfish(Dissostichus mawsoni) has an important ecological role and high commercial value. The otolith morphology of fish species differs across stages of life history. Therefore, otolith shape analysis can be used to infer life history of D. mawsoni. In this study, otoliths from 120 D. mawsoni individuals with four life stages randomly collected from the Ross Sea, Amundsen Sea, Weddell Sea and Lazarev Sea were used to analyze the otolith morphological differences of D. mawsoni at life stages by conventional measurement and elliptical Fourier analysis. The results showed that variation in otolith morphology occurred across life stages. Generally, the morphology of otolith was changed from smooth and low comple-xity to zigzagging and high complexity. The growth rate of otolith along the longitudinal direction was lower than that along the transverse direction. The characteristic parts of otolith, such as antirostrum, changed significantly across life stages. Compared to the linear discriminant analysis(71.9%), the elliptical Fourier analysis had the higher discrimination rate(85.4%), indicating that the elliptical Fourier analysis was more suitable to analyze the otolith morphology of D. mawsoni.