Comparison of morphological diversity and some biological parameters of mesopotamian nase, Chondrostoma regium (Heckel, 1843) from rivers of the Tigris basin, Iran

In the present study, the morphological variation and some biological parameters (growth pattern and condition factor) of 46 specimens of Chondrostoma regium collected from the Gamasiab, Dinevar, Qarasu and Zab rivers were analyzed. A total of 22 morphometric and 6 meristic characteristics were measured and counted, respectively. To investigate the morphological variations between studied populations, morphometric and meristic characteristics were analysed using One-way analysis of variance, Kruskal-Wallis, Principal Component Analysis (PCA), and Canonical Variates Analysis (CVA). The results showed that 16 morphometric and 5 meristic characteristics had significant differences (P<0.05). CVA analysis of morphometric traits showed that the populations had a high overlap and only the Zab River was separated from others, also in those meristic, Zab populations were separated from each other. Based on the results, C. regium showed significant morphological differences in meristic and morphometric discriminability characteristics. The growth pattern was isometric for Gamasiab, Dinevarr, and Qarasu populations but positive allometric for the Zab population. The condition factor was determined between 0.97 (Zab) and 1.06 (Dinevar), and there were no significant differences found between the studied rivers.