Investigation of Morphological Changes in Golden Mullet, Chelon auratus (Risso, 1810) from the Southern Caspian Sea Basin using the Geometric Morphometric Technique

During 2020-2021, to investigate the morphological variation of Chelon auratus, a total of 170 specimens were collected using beach seine nets from the shores of Astara (23 specimens), Anzali (33 specimens), Kiashahr (23 specimens), Langaroud (27 specimens), Roudsar (7 specimens), Chalous (30 specimens), Mahmoudabad (14 specimens), and Sari (13 specimens). At the sampling sites, after imaging from the left side of the specimens, 14 landmark points were defined and digitized on the two-dimensional images using the tpsDig2 software. The obtained data, after generalized Procrustes analysis, were analyzed using multivariate statistical analyses including principal component analysis (PCA), canonical variate analysis (CVA), and cluster analysis (CA). The deformation patterns of each population were illustrated in relation to consensus shapes on the deformation grids. The results showed significant differences in the body shape of the studied populations (P<0.05). These differences, related to head length, body depth, dorsal fin position, and caudal peduncle length, suggest the separation of populations in response to environmental conditions.