Pattern of phenotypic variation among three populations of Indian major carp Catla catla (Hamilton, 1822) using truss network system in the Ganga basin, India.

Abstract

Catla catla (Hamilton, 1822) is a commercially important freshwater cyprinid distributed widely in India and adjacent countries. In total 142 specimens of C. catla were collected from three geographically separate watersheds of Ganga basin. A truss network was constructed by interconnecting 12 landmarks to yield 30 distance variables that were extracted from digital images of specimens using tpsDig2 and PAST software. Transformed truss measurements were subjected to univariate analysis of variance, factor analysis and discriminant function analysis (DFA). A total of 28 distance variables exhibited significant differences between the populations. The principal component analysis generated seven components explaining 86.40 % of total intraspecific variance in populations. By applying step-wise DFA, 100 % of the specimens were classified into their original populations (98.5 % under a ‘leave-one-out’ procedure). The occurrence of distinct populations may be due to differences in physical and ecological parameters of the three tributaries of the Ganga basin .