R Re ec ce ei iv ve ed d: : 1 12 2 T PRINCIPAL COMPONENTS ANALYSIS OF CHONDROCHILUS REGINUS MORPHOLOGY

Corresponding Author: Email: yousefianeco@yahoo.com ABSTRACT: Tigris, are widespread in west of Iran and lives mostly in river and lake. They are omnivorous fish. This study aims to investigate population structure of C. reginus using Principal component Analysis. The study was conducted in three rivers that is the most remote headstream of the Gamasiab River in west part of Iran. Seven quantitative traits were measured for each specimen. After logarithmic transformation of the variables, the PCA first and second axis accounted for 38.4% and 17.6% of the total variance respectively. Considering correlation and contributions, the first axis showed an opposition between morphological variations (length parameters). The second axis showed an opposition between gonad weight and GSI. The third important factor in PCA analysis was the liver weight, HIS and visceral weight that was accounted for 12.6 % of the total variance. In conclusion there were precise differentiations among the three rivers samples in three factor estimated by PCA