RESEARCH ARTICLE Phenotypic Variations Among Three Populations of Chirruh Snowtrout, Schizothorax esocinus (Heckel, 1838) in Kashmir Himalaya with Insights from Truss Network System Javaid Iqbal Mir • Farooq Ahmad Mir • Rabindar Singh Patiyal Received: 2 January 2013 / Revised: 23 April 2013 / Accepted: 8 May 2013 Ó The National Academy of Sciences, India 2013 Abstract In the present study the intraspecific variation of Chirruh snowtrout, Schizothorax esocinus was investi- gated on the basis of morphometric characters using the truss network system that was constructed from the fish body. Altogether, 287 fish samples were collected from two rivers and one lake in Kashmir Himalaya. Data were sub- jected to principal component analysis, discriminant func- tion analysis and univariate analysis of variance. The first principal component explained 68.40 % of total variation while second and third components explained 7.30 and 4.81 % respectively. The step-wise discriminant function analysis retained two variables that significantly discrimi- nated the populations. Using these variables 85.1 % of the original groups were classified into their correct samples and 80.1 % of the cross-validated groups following omit- ting one procedure were classified into their correct sam- ples. Of the total 31 transformed truss measurements only 28 showed significant (P \ 0.05) difference among the populations. The findings of this study indicated the pres- ence of different stocks of S. esocinus from different water bodies of Kashmir Himalaya. Keywords Multivariate morphometrics  Schizothorax esocinus  Principal component analysis  Discriminant function analysis  Kashmir Himalaya  India Introduction Morphometric differences among stocks of a species are recognized as significant for evaluating the population structure and as a basis for identifying stocks [1–3]. Mor- phometric characters of fish are the measurable characters common to all fishes. Landmarks refer to some arbitrarily selected points on a fish body, and with the help of these points, the individual fish shape can be analyzed. In other words, a landmark is a point of correspondence on an object that matches between and within populations [4, 5]. Truss network systems constructed with the help of land- mark points are powerful tools for stock identification. A sufficient degree of isolation may result in notable mor- phological and shape differentiation among stocks of a species which may be recognizable as a basis for identi- fying the stocks [1]. Cyprinid fishes belonging to the subfamily Schizotho- racinae are widely distributed in mountain streams and lakes around the Himalayan Karakorum and Hindukush Ranges, the Tibet Plateau and Central Asia [6, 7]. Schizothorax esocinus, commonly known as Chirruh snowtrout, inhabit- ing cold streams, rivers and lakes [8] is distributed in the inland waters of Kashmir viz. Dal lake, Mansbal lake, Jhe- lum river, Lidder Stream [9], Nepal [10] and China [11] besides Afghanistan and Pakistan. S. esocinus is edible and is an important species for commercial and sport fishing. The IUCN status of this species has not been evaluated so far [12]. The population of S. esocinus has significantly dwindled after the introduction of Chinese carp (Cyprinus carpio) in the Kashmir valley [13] and adverse effect of increasing human activity over the decades [14]. The aim of this study was to examine the pattern and extent of morphological variations of S. esocinus from three water bodies of Kashmir Himalaya using the truss J. I. Mir (&)  R. S. Patiyal Directorate of Coldwater Fisheries Research, Indian Council of Agricultural Research, Bhimtal 263136, Nainital, Uttarakhand, India e-mail: r.javaid@rediffmail.com F. A. Mir Department of Zoology, University of Kashmir, Srinagar, India 123 Proc. Natl. Acad. Sci., India, Sect. B Biol. Sci. DOI 10.1007/s40011-013-0194-6