Microsatellite analysis of population structure in the shortfin mako (Isurus oxyrinchus)

Microsatellite analysis of the shortfin mako shark (Isurus oxyrinchus) revealed very weak evidence of population structure. Samples collected from the North Atlantic, South Atlantic, North Pacific, South Pacific, and Atlantic, and Pacific coasts of South Africa were screened at four microsatellite loci. Multilocus measures of population subdivision were much lower than expected (F_ST = 0.0014, P = 0.1292; R_ST = 0.0029, P = 0.019). Power analysis revealed that the study had a high level of power (>0.995) to detect the magnitude of F_ST expected based on a previous study of mtDNA and assumptions of equal male and female dispersal. Thus, integrating the results from microsatellite- and mitochondrial-based studies may provide evidence for gender-biased dispersal for the shortfin mako.