FEASIBILITY STUDY ON SPECIES IDENTIFICATION OF SCARIDAE FISHES FROM XISHA ISLANDS, CHINA, BASED ON OTOLITH MORPHOLOGY

In this study, parrotfish were obtained in the sea area of Xisha Islands from 2018 to 2021. Their identification was analyzed by 19 otolith morphological indicators selected by traditional morphometry, along with 77 elliptical Fourier coefficients (eFcs) selected by elliptical Fourier analysis. This comprehensive approach aimed to investigate the feasibility of otolith morphology in the identification of species in the Scaridea family. The results showed that the comprehensive discriminant rate was 56.8% when using only otolith morphological indicators to identify parrotfish. This rate was lower than the 63.1% achieved by utilizing only eFcs and the impressive 75.7% when combining both parameters. However, the combination of these two parameters significantly enhanced the discriminant rate to 88.6% for 4 genera, with Calotomus achieving a perfect 100% discrimination rate. The clustering results based on otolith morphology for the 15 Scaridea species largely align with the evolutionary tree results obtained from the study of mitochondrial genes. This agreement, especially at the genus level, showing a high degree of agreement, confirming that otolith morphology has genetic properties and illustrating the feasibility of otolith morphology for fish species identification. The results of this study contribute essential scientific information to the basic research of parrotfish in Xisha Islands and establish a theoretical foundation for the conservation and development of parrotfish resources.