Otolith Outline Morphometrics Reveal Species-Level Differences Between Two Morphologically Similar Picarels, Spicara flexuosum and Spicara maena
Thalassas, cilt.42, sa.4, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 42 Sayı: 4
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s41208-026-01233-x
- Dergi Adı: Thalassas
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Zoological Record, Natural Science Collection (ProQuest), Biological Science Database (ProQuest)
- Anahtar Kelimeler: Elliptic fourier descriptors, Mediterranean sea, Outline-based morphometrics, Spicara flexuosum, Spicara maena, Wavelet transforms
- Ondokuz Mayıs Üniversitesi Adresli: Evet
Özet
Accurate species identification of closely related fish species in the marine ecosystem is important in fisheries management, biodiversity surveys, and stock studies, especially when the resolution of external morphological features is limited. In such cases, otolith shape may provide a more reliable phenotypic marker. This study evaluated both conventional shape indices of the otolith and outline-based shape analysis for discriminating morphologically similar congeneric picarels, Spicara flexuosum and Spicara maena, from commercial catches along the Turkish Mediterranean coast, broadly associated with the Gulf of Antalya and the Gulf of Iskenderun, during the 2023 fishing season. Although the aspect ratio and roundness of the sagittal otoliths differed significantly between the two species, multivariate analyses indicated that conventional shape indices of the otolith did not reliably discriminate between the species. By contrast, outline-based analyses detected clear and significant interspecific differences. Elliptic Fourier analysis and wavelet transform analysis achieved original classification accuracies of 91.3% and 87.7%, respectively. Combining the retained EFA- and WT-derived scores increased overall classification accuracy to 92.8%, which was maintained under leave-one-out cross-validation, supporting the complementary value of the two outline-based approaches. Overall, the outline-based approaches showed stronger discriminatory performance than conventional shape indices in the present dataset. These findings support the value of integrative otolith-based shape analysis as a useful complementary approach for resolving taxonomically challenging species in the Mediterranean region.