Ecomorphological patterns and shape indices of otoliths in the Pagellus acarne (Actinopterygii, Sparidae) from the Aegean and Marmara Seas

: Pagellus acarne is found in coastal waters worldwide and it includes important species of commercial and recreational fisheries. In this study, 16 morphometric variables of the sagittal otolith, including six morphometric characters, six shape indices, and four ecomorphological indexes, were investigated for the first time among P. acarne stocks collected from the Aegean and Marmara Seas coasts of Turkey. Statistically significant differences were found between the right and left otolith variables of P. acarne individuals in both stocks (p < 0.05). Similarly, significant differences were observed on the same side between stocks (p < 0.05). The right otoliths exhibited higher discrimination power than the left within the two stocks. The PCA showed that only five (31.25%) (otolith area, otolith perimeter, form factor, roundness, and edge complexity index) out of the sixteen variables were quite important characters in the differentiation between stocks. These otolith characters demonstrated a very high rate of accurate discrimination (99.0%) between stocks. The results indicated otolith morphometric characters, shape indices, and ecomorphological indexes can be used as suitable tools to discriminate P. acarne stocks. This is the first study to include all otolith characters such as morphometrics, shape, and ecomorphological indices that discriminate between P. acarne stocks from these localities.