Binushma Raju, Sreeja P. Sreedhar, Leji J. and Sawmiya Udayan
Abstract
The present study evaluated ecomorphological differences and microhabitat associations in sympatric Puntius assemblages inhabiting the upstream reaches of the Kallada River in the Western Ghats. Sampling was done from February 2020 to January 2021 across distinct microhabitats differing in depth, flow velocity, substratum composition, and instream cover. Twenty-five ecomorphological indices related to locomotion, habitat positioning, and foraging were analysed for seven sympatric species. PCA grouped species in the morpho space, and PERMANOVA indicated significant ecomorphological differentiation among species (F = 2.168, p = 0.0001). SIMPER analysis identified locomotory and trophic traits (Aspect ratio of Caudal Fin, Aspect ratio Anal Fin, Aspect ratio of Pelvic fin, and Relative length of digestive tract) as the major contributors to functional dissimilarity. CCA indicated that species distribution is associated with substratum composition, depth, vegetation cover, and flow conditions. The study indicates that microhabitat heterogeneity promotes functional divergence and coexistence among sympatric Puntius species.