Genetic diversity of white sharks, Carcharodon carcharias, in the northwest Atlantic and southern Africa

The white shark, Carcharodon carcharias, is both one of the largest apex predators in the world and among the most heavily protected marine fish. Population genetic diversity is in part shaped by recent demographic history and can thus provide information complementary to more traditional population assessments, which are difficult to obtain for white sharks and have at times been controversial. Here, we use the mitochondrial control region and 14 nuclear-encoded microsatellite loci to assess white shark genetic diversity in 2 regions: the Northwest Atlantic (NWA, N = 35) and southern Africa (SA, N = 131). We find that these 2 regions harbor genetically distinct white shark populations (Φ ST = 0.10, P < 0.00001; microsatellite F ST = 0.1057, P < 0.021). M-ratios were low and indicative of a genetic bottleneck in the NWA (M-ratio = 0.71, P < 0.004) but not SA (M-ratio = 0.85, P = 0.39). This is consistent with other evidence showing a steep population decline occurring in the mi...