Morphometry and molecular insights into three species of Balistidae family from the South-eastern Arabian Sea, India

Aim: The present investigation aimed to evaluate the mitochondrial COI and 16s rRNA gene sequences of three balistid species—Abalistes stellaris, Sufflamen fraenatum and Odonus niger—to assess the genetic congruence and phylogenetic relationships from the waters along the south-west coast of India. Methodology: Three species of balistids—Abalistes stellaris, Sufflamen fraenatum and Odonus niger procured from three major marine landing centres of Karnataka were examined for morphometry and genetic identification using partial sequences of the COI and 16S rRNA to distinguish between species and understand their relationships. Results: The morphometric measurements of Odonus niger and Abalistes stellaris showed a narrow range of coefficient of variation, suggesting minimal or very low intra-population variation, whereas Sufflamen fraenatum displayed a wide range, indicating high intra-population variation. The intra- and inter-species sequence divergence values, based on the COI gene, ranged between 0.0034 to 0.0051 and 0.1549 to 0.1824, respectively. Interpretation: The present analysis clearly distinguished the three balistid species from the south-eastern Arabian Sea, aligning with established Balistidae taxonomy. The findings underscore the value of morphometric analysis in species identification and population assessment, offering a foundation for future genetic and evolutionary studies crucial for effective fisheries management and conservation. Key words: Arabian Sea, Balistidae, COI, Triggerfish, 16S rRNA