Intraspecific Morphological Discrimination Between the Stocks of Schizothorax curvifrons (Sattar Gad), Inhabiting the Water Bodies of Cold Indian Himalayan Region, Using Truss Network System

Abstract

Identification of Schizothorax curvifrons (Sattar gad) stocks in Kashmir water bodies is crucial for the conservation of species that are losing ground daily. Because of substantial overfishing and pollution in the fish's natural environment, the wild population of these fishes is drastically dropping, which is a troubling situation that justifies a high priority for conservation. Fish populations can acquire morphometric variations as a result of prolonged isolation and interbreeding. The goal of this study was to use the truss network approach to delineate the stock structure of S. curvifrons based on morphological attributes. A total of 167 fish specimens were gathered from the three sampling stations of Kashmir waters, viz. Telbal Nallah, Dal Lake and Anchar Lake. A total of 37 truss distance measurements were established by joining 15 morphometric landmark points on the fish body. For the fish species currently targeted, MANCOVA demonstrated significant (p < 0.001) morphological heterogeneity among sampling locations. Univariate ANOVA test showed statistically significant differences in 21 out of the total 37 studied morphometric variables among the three sampling sites for S. curvifrons. Based on principal component analysis, the first component (PC1) explained the maximum amount of variation in samples, which is 26.9%. The second component (PC2) contributes 16.5%, and the third (PC3) 10.3% of the total variance. Wilk's lambda test found substantial (p < 0.001) differences in the morphometric measures of the fish across all sampling sites. The discriminant function analysis identified two morphological indices that explained 58.8% and 42.2% of the differences between the groups. Discriminant function analysis further revealed 84.6% correctly classified individuals into their respective populations. The findings from this investigation can be used to develop stock-specific management and conservation strategies for the long-term protection of S. curvifrons in Kashmir water bodies.