Geometric and morphometric analysis of fish scales to identity genera, species and populations case study: the Cyprinid family

Using fish scale to identity species and population is a rapid، safe and low cost method. Hence، this study was carried out to investigate the possibility of using geometric and morphometric methods in fish scales for rapid identification of species and populations and compare the efficiency of applying few and/or high number of landmark points. For this purpose، scales of one population of Luciobarbus capito، four populations of Alburnoides eichwaldii and two populations of Rutilus frisii kutum، all belonging to cyprinid family، were examined. On two-dimensional images of the scales 7 and 23 landmark points were digitized in two separate times using TpsDig2، respectively. Landmark data after generalized procrustes analysis were analyzed using Principal Component Analysis (PCA)، Canonical Variate Analysis (CVA) and Cluster Analysis. The results of both methods (using 7 and 23 landmark points) showed significant differences of the shape of scales among the three species studied (P<0. 001)، but no significant differences among their populations (P>0. 05). The results also showed that few number of landmarks could display the differences between scale shapes. According to the results of this study، it could be stated that the scale of each species had unique shape patterns which could be utilized as a species identification key.