Asian Journal of Research in Zoology

Background: Morphometric differentiation occurs in fishes within the same ecosystem or river when populations experience distinct microhabitats due to the dynamic nature of water physicochemical characteristics, such as water flow, food availability, and predation. It may offer survival benefits under changing environmental conditions to a certain extent.

Aim: The study was conducted to compare five populations and both sexes of Sperata seenghala (Sykes, 1839) in the Gomati River, Tripura, India, using 30 morphometric assessment criteria.

Method: The morphometric data used to quantify shape variation were analysed using the coefficient of variation (CV), principal component analysis (PCA), and UPGMA clustering.

Results: PCA performed on the morphometric data accounted for total variations of 78.62% (59.181% + 19.448%) and 95.73% (86.649% + 9.085%) in the first two principal components (PC1 and PC2) for male and female populations, respectively. The UPGMA dendrogram showed that, among males, the Maharani and Kakraban populations shared the most similar characteristics, whereas Sonamura was the most morphologically distinct population compared with the other populations. Among females, the Jatanbari and Amarpur populations shared the most similar characteristics, while Sonamura was an outlier compared with all other groups.

Conclusion: The findings provide insights into distinct morphological variation among populations of both sexes, demonstrating morphometric differentiation across five geographically distinct stretches of the Gomati River in Tripura. Further study is required to link these patterns with environmental variables and to assess adaptation to changing habitats through phenotypic plasticity and natural selection.