Taxonomic validation of areolate grouper, epinephelus areolatus (Perciformes: Serranidae) along the nizampatnam coast, india

Abstract

Groupers (Perciformes: Serranidae: Epinephelinae) are a significant group of marine and estuarine fishes having ecological and commercial importance in tropical and subtropical waters. The genus Epinephelus is identified based on the color configuration and morphological characteristics. The homogeneity in the morphological characteristics has created confusion in the species identification of Epinephelus. Epinephelus areolatus with its delicious taste has high economic value; however, its population showed a remarkable decline in recent times due to overfishing. Due to morphological resemblance, it has often been confused with Epinephelus chlorostigma and Epinephelus bleekeri, which leads to misidentification. Hence, correct identification of species is needed for the proper management of fish resources. This study aims to identify and validate E. areolatus by using morpho-meristic characteristics, including the number and pattern of pyloric caeca, vertebrae count through radiograph imaging, scale and otolith morphology, and DNA barcoding. The morphological and meristic characteristics of Epinephelus species observed in Nizampatnam coast are strikingly comparable to those reported earlier as E. areolatus. Comparative molecular analysis was also carried along with other morphologically similar species, viz. E. chlorostigma and E. bleekeri, using mitochondrial cytochrome oxidase I gene sequences. The mean interspecific genetic distance revealed high similarity with E. bleekeri (0.109 ± 0.012) and low similarity with E. chlorostigma (0.079 ± 0.009). The neighbor-joining tree has shown distinct clades for three species with high bootstrap values. The partial DNA sequence of the mitochondrial cytochrome oxidase I was established for the first time for E. areolatus from the Nizampatnam coast in this study.