Otolith geographic variability is investigated as a tool for fish stock discrimination. Despite increasing studies of otoliths in marine ecosystems, feasibility of otolith shape as an investigative tool in freshwater fish assemblages needs to be validated. The aim of this study was to test stocks of Gymnocypris selincuoensis that may be distinguished using otolith shape from three rivers and eight lakes in northern Tibet. Shape indices (SDs) (form-factor, circularity, rectangularity, ellipticity, roundness, surface density and aspect ratio) and normalized Elliptic Fourier descriptors (NEFDs) were analysed by multivariate statistical procedures. To examine the differences of otolith shape from different sites, metric multidimensional scaling and a linear discriminant analysis were used for the SDs and NEFDs. The results of the linear discriminant analysis indicate that riverine otolith stocks had higher rates of successful classification compared with lacustrine otolith stocks, and stocks of otoliths from the Chargut Co and the Kyaring Co lakes had the highest rates of misclassification. Although a 70% classification success rate was produced by Bochu Tsangpo, the differences in otolith shape among 11 stocks were not very noteworthy. The information generated in this research can be used as a reference for stock discrimination of G. selincuoensis from the Tibetan Plateau. Further research is needed to explore the causes of shape variation.
To share on other social networks, click on any share button. What are these?