Genetic species identification and population structure of grouper Epinephelus coioides (Hamilton, 1822) collected from fish markets along the Persian Gulf and the Oman Sea

Many ecologically important and valuable fisheries marine species have been misidentified in terms of both the statistical data and market demand. Correct identification at the species level and the population genetic structure of the orange-spotted grouper (Epinephelus coioides), a precious fish in the Persian Gulf and the Oman Sea, was tested using mitochondrial cytochrome oxidase subunit I (DNA barcoding) and D-loop sequencing. The results revealed that the Epinephelus species found in the region, including E. coioides, E. bleekeri, E. polylepis, and E. chlorostigma were all mistakenly grouped together and identified as only E. coioides. Moreover, the analysis of molecular variance (AMOVA) of E. coioides samples using the D-loop showed a significantly unique genetic structure (phi ST = 0.068, p < 0.001) within the E. coioides population throughout the Persian Gulf and the Oman Sea, with the pairwise genetic difference between sampling locations in UAE and the Iranian coast. Moreover, D-loop sequences analysis showed two distinct haplotype groups scattered among the sampling locations, which did not correlate with the geographic distance between the sampling locations. These findings indicate that the issue of misidentification should be highlighted in the management and conservation of E. coioides. As this type of misidentification is likely to happen to other threatened marine species as well, the efficacy of using genetic markers for the correct identification, both at the species and the population level, is vital.