Microsatellite markers reveal population structure in gilthead sea bream Sparus auratus from the Atlantic Ocean and Mediterranean Sea

This study was carried out to investigate the genetic variability and the population genetics of Sparus auratus. In fact, despite its importance in Mediterranean fisheries and aquaculture, very little it is known concerning its population structure. Samples of wild gilthead sea bream were collected in seven different localities along the Mediterranean and Atlantic coasts and were genetically characterized by means of microsatellite markers. Genotyping at four microsatellite loci revealed high polymorphism (7-38 alleles/locus) and expected heterozygosities, which ranged from 0.80 to 0.85. A slight but significant population structure was found (F-ST = 0.010). In fact, at least three populations of gilthead sea bream within the Western Mediterranean Sea were identified (Sardinian Sea, Sardinian Channel and Central Tyrrhenian Sea), which are also genetically differentiated from those of the Atlantic Ocean and the Adriatic Sea.