Otolith morphometry and shape analysis of six fish species caught from Tersakan stream in Samsun province

Because otolith morphology is known to be species-specific, these structures have long been considered useful tools for fish identification and discrimination. In this study, lagenar (asteriscus) and utricular (lapillus) otolith morphology of six Cypriniform fish species (Barbus tauricus, Capoeta tinca, Abramis brama, Alburnoides kurui, Scardinius erythrophthalmus and Squalius cephalus) obtained from Tersakan Stream in Samsun province (Türkiye) were described based on scanning electron microscopy images. In addition, interspecies differences in otolith shape were evaluated with shape indices, elliptic Fourier coefficients and wavelet transform. Morphological analysis of otoliths revealed that lapilli have more species-specific diagnostic characters than asterisci. Otolith shape analysis was found to be more effective than morphometric analysis in species discrimination. However, the highest classification success was achieved in the wavelet transform technique applied to lapillus otoliths with 90.6%. The results of this study suggest the usefulness of otolith morphology for differentiation of Cypriniform fish species, confirming that the otolith shape is species-specific.