Phylogenetics of three endangered freshwater catfish species (Actinopterygii, Siluriformes) inferred from COI gene barcoding and morpho-meristic traits

This study validated morphometric and genetic approaches to evaluate the population structure and genetic diversity of three endangered and economically significant catfish species: Bagarius bagarius (Hamilton, 1822); Clupisoma garua (Hamilton, 1822); and Eutropiichthys vacha (Hamilton, 1822), in the riverine system of Punjab (Chenab, Indus, and Jhelum rivers), Pakistan. This study aimed to create a reliable method for fish identification and to provide critical standard data for their conservation. Fish samples from the designated riverine populations were morphologically identified and then authenticated through DNA barcoding and phylogenetic analysis using mitochondrial cytochrome c oxidase subunit I ( COI ) gene sequence. Principal component analysis (PCA) suggests a clear relationship between species and morpho-meristic characteristics. Maximum Likelihood (ML) trees were constructed using MEGA 11 under the K2P model. The dataset for the ML analysis included reference COI sequences from the confamilial and congeneric species. Findings of morphometric analysis showed a distinct morphological variation in all species, especially Bagarius bagarius , showing a unique profile. This finding was powerfully corroborated by genetic analysis of the COI gene, which confirmed three distinct genetic groups corresponding to the three species. The mean interspecific genetic divergence was a substantial 0.112, while intraspecific variation was minimal (0.001–0.002). This study utilizes a crucial and accurate identification method for these endangered catfish species. DNA barcoding proved to be a highly effective and reliable tool for confirming the identification of these catfish species, complementing and validating our findings of traditional morphological methods. Information on population structure and genetic variation obtained from the presently reported study is helpful for providing essential foundational data for informing conservation efforts and fisheries management in the region and highlighting the power of an integrated approach for species assessment.