Comparative otolith morphology in two species of Salmo genus from Türkiye

Abstract

In this study, the morphology of the sagittal otolith of Salmo coruhensis Turan, Kottelat & Engin, 2010 and Salmo fahrettini Turan, Kalayci, Bektaş, Kaya & Bayçelebi, 2020 from Çam Stream (Artvin) and Terme Stream (Samsun) was described by images of scanning electron microscopy. Its shape and contour were also analyzed with shape indices, elliptic Fourier coefficients and wavelet transforms. As the study material, a total of 30 S. coruhensis sample and 20 S. fahrettini sample were obtained. Interspecies differences in otolith shape and morphometry were evaluated by principal components analysis, canonical discrimination analysis, and permutational multivariate analysis of variance. The two salmonid species studied were distinguished by both morphometric and shape analysis methods. However, wavelet transform was found to be more effective than shape indices and elliptic Fourier coefficients in species discrimination, with an overall classification success rate of 80%. Our results showed that saccular otolith morphology could be an additional diagnostic character for trout species differentiation.