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Exploring otolith phenotypic variability as a marker to discriminate spatial stocks of Mystus vittatus (Bloch, 1794)

Lubna Yasmeen, Mohd Sadiq , Mohammad Afzal Khan , Insha Hassan

Abstract

Context. Mystus vittatus is an economically significant food and aquarium fish currently experiencing a decline in mature individuals. Aim. This study aims to delineate the spatial stocks of M. vittatus in the River Ganga by analysing otolith shape and morphometry. Methods. The otolith shape variations across four sampling stations along the river Ganga was assessed using wavelet coefficients, otolith morphometric parameters, including size and shape indices. Key results. The statistical analyses, including Permutational Multivariate Analysis of Variance (PERMANOVA), canonical analysis of principal coordinates (CAP), and ANOVA-like permutation test, revealed significant differences in otolith shape among the four populations. Kruskal-Wallis and post-hoc Dunn's tests confirmed significant differences in most otolith morphometric parameters across the populations. Principal component analysis (PCA) explained 35.6% and 26.2% of the total variance in PC1 and PC2, respectively, for otolith morphometric parameters. The random forest method achieved a classification accuracy of 64.68% based on otolith shape and 52.04% based on otolith morphometry. Conclusions. The observed phenotypic variabilities in otolith morphology among the four populations suggest the presence of heterogeneous stocks. Implications. These findings provide valuable insight for effective fisheries management and conservation strategies aimed at sustaining M. vittatus populations in the River Ganga.

MF24280  Accepted 31 July 2025

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