Genetic characterization of four hatchery populations of the seven-band grouper (Epinephelus septemfasciatus) using microsatellite markers

The seven-band grouper Epinephelus septemfasciatus is of considerable economic value and a candidate species for aquaculture in East Asia. Genetic characterization of hatchery populations is needed to maintain their genetic diversity and to develop more effective aquaculture practices. We analyzed the genetic structure of four cultured populations of E. septemfasciatus in Korea using 13 microsatellite markers. The number of alleles per locus ranged from 5 to 16, with an average of 9.6. The mean observed and expected heterozygosities were 0.699 and 0.679, respectively. Pairwise multilocus FST tests suggested the existence of two populations, although the isolation-by-distance model was rejected. An analysis of molecular variance (AMOVA) also revealed two genetic clusters. These results could reflect current aquacultural practices, with breeds and eggs exchanged between hatcheries, and/or genetic drift due to intensive breeding practices. Therefore, for the optimal management of resources, the genetic variation of hatchery stocks should be monitored and inbreeding controlled for the seven-band grouper stocks. This genetic information will be useful for the management of E. septemfasciatus fisheries and the aquaculture industry.