GENE DIVERSITY ANALYSIS IN NATURAL-POPULATIONS AND CULTURED STOCKS OFTURBOT (SCOPHTHALMUS-MAXIMUS L)

The genetic variability of eight fish-farm and three natural populatio ns of turbot was studied by electrophoretic analysis of 35 enzymatic l oci. The results showed low genetic variability in natural populations of turbot (H-T = 0.029 +/- 0.013) in comparison with other flatfish s pecies. Great genetic similarity was revealed among the natural popula tions studied, which indicates high rates of gene flow in this species . The hatchery stocks showed less genetic variation than the wild popu lations analysed, which suggests genetic drift phenomena involved in t he foundation and management of broodstocks. In addition, the heterozy gosity differences detected among the hatchery stocks analysed are cor related with inverted levels of fluctuating asymmetry, which supports the existence of inbreeding depression phenomena in turbot culture.