Morphometric variation among four populations of Shemaya (Alburnus chalcoides) in the south of Caspian Sea using truss network

Abstract

To analyze the morphometric differentiation among four groups of Shemaya, Alburnus chalcoides (Guldenstadf, 1772), sited in four habitats i.e.: Lisar, Shiroud, Babolroud rivers and Anzali region (southern part of the Caspian Sea), truss network analysis was employed to take multivariate analysis. Truss characters between fourteen selected landmarks on 357 specimens were measured, then allometric method was used to obtain size-adjustment shape data. Multi and univariate analysis of variance revealed significant differences between means of four populations and sexes (P<0.01). In principal component analysis of the shape variations among the populations, the first two components accounted for 50% and 56.6%, of males and females, respectively. The loadings of the first and the second principal components and discriminant functions showed that the differences were located mainly on abdominal, caudal regions and length of fins, indicating to be important in description of the population characteristics. Results indicated that samples of Anzali region were clearly distinct and diverged from other three populations probably because of difference in the habitat condition. Generally female samples showed more morphometric differences than male samples did, but their influence on this issue remained unknown.