Biological and genetic structure of <i>Epinephelus costae</i> (Steindachner, 1878) population in Iskenderun Bay, eastern Mediterranean Sea

This study aimed to status of the Iskenderun population of <i>Epinephelus costae</i>, an important fish species in the Mediterranean Sea ecosystem, by providing detailed data on its genetic structure using mtDNA COI gene region and biological parameters as length-weight relationship, age-growth characteristics, von Bertalanffy growth parameters. A total of 325 specimens were studied from Iskenderun Bay in the eastern Mediterranean (Türkiye), ranging in length from 16.7 to 43.5 cm. For genetic studies using the mtDNA COI gene region, 30 samples were selected from different size groups representing the population. Age 2 represented the majority of the population (31.69%). The value of "b" of the length-weight relationship was higher than "3" (3.0839). The results for the von Bertalanffy growth parameters were observed as <i>L</i> _<i>α</i> = 125.8 cm; <i>k</i> = 0.0570 year -1; <i>t</i> ₀ = - 2.2410 year. Fulton's condition factor was observed as 1.4120. The growth performance index was calculated as 4.35. The genetic diversity of the population was found to be 0.0332 ± 0.0028. Sixteen haplotypes were observed in the population and haplotype diversity was calculated as 0.9379. Tajima's neutrality test (-0.9437), Fu's Fs Statistic (-0.0340), Strobeck's S Statistic (0.6620), Achaz's Y test (-1.8728), Fu and Li D (1.1570) and F Test (0.4444) were applied to test whether the population is in balance. In conclusion, the biological and genetic analyses carried out within the scope of our study revealed that the Iskenderun population of <i>E. costae</i> is in stable condition.