Evaluating the Use of Otolith Shape Analysis to Identify the Spatial Stock Structure of Seabream, Diplodus annularis (Sparidae)

Abstract

Otoliths are hidden boxes that form the basis of fishing studies and record all the characteristics of the life histories of fish. Otolith morphometry and shape analysis are used to effectively distinguish fish stocks from each other. The present study deals with the discrimination of D. annularis stocks from the Aegean Sea, Black Sea and Mediterranean Sea coasts of T & uuml;rkiye using the otolith morphology and otolith shape analysis. In this study, a total of 169 Diplodus annularis samples were collected from three important seas between September 2023 and March 2024. No significant differences were found between the left and right otoliths as well as between otoliths of males and females (p > 0.05). Sagittal otoliths were subjected to shape indices, elliptic Fourier analysis, and wavelet analysis for stock discrimination. Among the three methods, WT was determined as the most effective discrimination method with an overall 62.7% classification success. The results of the discrimination between the samples for these three methods showed differences, but in general, the otoliths of seabream in the studied stocks did not differ significantly in terms of both shape indices and Fourier coefficients, while the results of WT supported the view that stocks could be separated using otolith shape (PERMANOVA, p = 0.0001).