Genetic diversity and population structure of goldblotch grouper Epinephelus costae in the central Mediterranean Sea using mtDNA (Cyt b) and microsatellite loci

The objective of this study was to describe the genetic population structure and demographic history of the goldblotch grouper of Central Mediterranean Sea (Gulf of Gabes and the coast of Libya) using cytochrome b (cytb) gene and seven nuclear microsatellites. Based on 940 base pairs of the cytochrome b segment, we found high levels of genetic variability for the two samples analysed (h = 0.833 +/- 0.054 and h = 0.769 +/- 0.120 respectively in Tunisia and Libya). Pairwise F-ST statistics among the two localities were negative (F-ST = -0.015; cytb gene) or low (F-ST = 0.011; microsatellite loci), suggesting a widespread gene flow. The high dispersal capabilities of larvae of E. costae coupled with the limited physical barriers in marine environment may be responsible for the high gene flow among E. costae populations along the two sites (Gulf of Gabes and Tadjourah). In summary, this study provides a preliminary assessment of geographical patterns of differentiation of E. costae in this region for conservation, management and stock identification.