Geometric morphometric comparison of trout barb, Capoeta trutta (Teleostei: Cyprinidae) in the Tigris River basin

A total of 136 specimens of trout barb, Capoeta trutta (Heckel, 1843) from eight rivers of the Tigris Basin were caught by seine net to compare their shape using geometric morphometrics. After anesthesia, using 1% clove oil solution, the specimens were fixed in 10% buffered formalin and transferred to the Ichthyology Museum of Isfahan University of Technology for further studies. The left sides of the specimens were photographed using a copy-stand equipped with a digital camera. To extract body shape data, 13 homologous landmark-points were digitized using tpsDig2 software. After GPA superimposing, the landmark data, were analyzed using Principal Components Analysis (PCA), Canonical Variate Analysis (CVA) and Cluster Analysis (CA) to explore the patterns of variation in their body shape. All multivariate analyses were computed using PAST software. The consensus configuration of populations was visualized using the wireframe graphs in MorphoJ to compare their shape difference. The PCA, CVA and CA showed differences among the populations, especially, between Konjancham and other populations. This result showed that geometric morphometric methods could separate trout barb populations of the Tigris River Basin from each other to a great extent. Potential factors contributing to the observed variations include differences in physicochemical parameters of rivers and geographic distance among the populations. However, for more details, molecular studies are needed.