Stock identification of Congaturi halfbeak (Hyporhamphus limbatus): insight into conventional and truss-based morphometrics

Abstract

BackgroundWild fish stocks continuously decline in Bangladeshi rivers and oxbow lakes. Small indigenous fish species management solely depends on their population status and conservation. This study aimed to determine the population status of Hyporhamphus limbatus, in Southwestern Bangladesh using conventional and truss morphological characteristics.ResultsA total of 174 fish samples were procured from monsoon season i.e., May to August 2018 the Bhairab River, BR; Kopotakkho River, KR; and Baluhar Baor, BB in Bangladesh. Five meristics, six conventional and twelve truss-based morphometric characters, were considered for stock identification. The Kruskal–Wallis test helped to analyze the meristic characters, while ANOVA, principal component analysis (PCA), discriminant function analysis (DFA), correct classification analysis using DFA, and a UPGMA dendrogram formation were used to investigate the conventional and truss measurements. By the Kruskal–Wallis test, no meristic characters showed significant differences across different populations. Eleven of the 18 morphometric measurements showed significant differences among three populations through the univariate ANOVA. PCA specified the population structure variations and explained 67.438% of the total variance. The first and second discrimination functions accounted for 78.3% and 21.7%, representing 100% of the group variability. Similarly, 85.6% of the grouped cases and 77.6% of cross-validated grouped cases were initially effectively represented by their correct number of individuals. A dendrogram based on morphometric (conventional and truss) displayed three stocks grouped into two clusters, with BR forming a distinct cluster, while KR and BB creating a shared cluster.ConclusionIn conclusion, such morphological differences are most likely due to their distinctive ancestral origins. This study presents novel reports on the stock assessment of H. limbatus in their natural ecosystem. Furthermore, molecular research and an evaluation of the environmental impact on H. limbatus populations in Bangladesh are strongly recommended.