Comparative analysis of otolith morphology in three species of Scomber

Abstract

Geometric morphometrics is a quick and reliable approach to differentiate fish stocks based on the variation of otolith shapes. In this study, morphometric analysis of otolith shapes was used to differentiate three species of Scomber. The sagittae morphology of S. scombrus otolith is totally different from that of S. japonicus and S. australasicus. Multivariate analysis consistently showed that S. japonicus was morphologically similar to S. australasicus, whereas a significant difference in otolith shapes was detected between S. scombrus and other two species of Scomber. The rostrum, antirostrum, excisural notch and dorsal-posterior margin of the otolith reflect the main variations between the three species of Scomber. Shape indices and Fourier coefficients were used to discriminate fish species using analysis of variance and Fisher discriminant analysis. The shape indices successfully differentiated 100%, 95.7% and 96.4% of otoliths in S. japonicus, S. australasicus and S. scombrus, respectively, while the Fourier coefficients only discriminated 70.0%, 61.9% and 91.3% of the sagittae in S. japonicus, S. australasicus and S. scombrus. This study indicates that the shape analysis on the sagittae morphometrics of otoliths is a better method to differentiate species of Scomber.