基于4种形态学技术的裘氏鳄头冰鱼与南极小带腭鱼耳石外型比较研究

Comparative analysis on otolith shape of Champsocephalus gunnari and Cryodraco antarcticus based on four morphological techniques

为研究多种形态学技术对南极冰鱼耳石的种群分类效果,利用裘氏鳄头冰鱼(Champsocephalus gunnari)和南极小带腭鱼(Cryodraco antarcticus)样本,对描述耳石的5种基础形态学参数进行分析并转换为7种形状指标,比较分析了两种冰鱼间的耳石形态学差异,再利用主成分分析、逐步判别分析法和随机森林法对两种耳石的77个傅里叶系数进行判别。结果表明,两种冰鱼的耳石参数和体长均有显著的相关性(P>0.05),裘氏鳄头冰鱼的体长与部分耳石参数呈幂函数关系,而南极小带腭鱼耳石的长、高、面积、周长、质量与体长均呈对数关系。裘氏鳄头冰鱼较南极小带腭鱼耳石环率更低,即更趋近于圆,更为规则。传统的形态学测量方法无法区分两类耳石,主成分分析可较好地区分两种鱼类的耳石,而逐步判别分析和随机森林分析的判别率分别达到98.78%和91.67%。逐步判别分析在小样本分析中具有优势,随机森林分析则适用于大样本判别。

To study the effectiveness of otolith morphological techniques on the population classification of Antarctic ice fish,based on the collected samples of Champsocephalus gunnari and Cryodraco antarcticus,5 kinds of basic otolith morphological parameters were measured and converted into 7 morphological indicators,the differences in otolith morphology of two species were compared and analyzed,principal component analysis(PCA),stepwise discriminant analysis(SDA)and random forest(RF)were then used to discriminate the 77 elliptical Fourier harmonics of otolith morphological parameters.The results showed that the otolith parameters and body length of two species were significantly correlated(P>0.05).The body length of C.gunnari showed a power function relationship with some morphological parameters.While otolith length,otolith height,otolith area,otolith perimeter,otolith mass of C.antarcticus were all in logarithmic relationship with the body length.It could be seen that the otolith ring rate of C.gunnari was lower than that of C.antarcticus,compared to the otolith of C.antarcticus,the otolith of C.gunnari was rounder and more regular.The conventional morphological analysis could not discriminate the otoliths of two species.The PCA could discriminate the otoliths of two species,and the discriminant success rates of SDA and RF were 98.78%and 91.67%,respectively.SDA has its advantage in small sample size,but RF is suitable for large sample size.