Comparative morphometrics of two populations of giant river catfish (Mystus seenghala) from the Indus river system

Abstract

Giant river catfish (Mystus seenghala) from the Beas river were compared with a population in the Sutlej river of theIndus river system using 28 morphometric characters. Discriminant analyses and a univariate ANOVA were used toexplore these data. Allometric transformation of each measurement was done to eliminate correlations with size. Thestepwise discriminant analysis retained nine variables that significantly discriminated the Beas samples from theSutlej samples. Using these variables, 91.2% (original) and 89.0% (cross validated) of fish were classified into theircorrect samples. Misclassification was higher for the Sutlej samples (12.5%) than for the Beas samples (6.3%). Theresults of the discriminant analyses showed that variability in the Beas samples was more homogeneous andprovided a more characteristic picture of the group than the Sutlej samples. The univariate ANOVA revealed signifi-cant differences between the means of the two populations for 12 of the 28 transformed morphometric measurements .