Mitochondrial DNA diversity and phylogeographic patterns among South African Cape fur seals, Arctocephalus pusillus pusillus

Abstract

Cape fur seals (Arctocephalus pusillus pusillus) are important apex predators and indicators of ecological health. Historically, their populations were severely reduced by the activities of sealers and guano collectors but has since increased due to legislation controlling, then banning these activities. This study aimed to assess the genetic diversity and population structure of Cape fur seals in Southern Africa's cool (Benguela) and warm (Agulhas) temperate regions. Cape fur seal genetic material (n = 263) was collected along the Agulhas Bank and analysed using mitochondrial cytochrome b and D-loop gene markers. Estimates of genetic parameters showed that the south and west populations of Cape fur seals had high levels of haplotype diversity and low levels of nucleotide diversity. Assessment of genetic structure indicated that there was no obvious phylogenetic pattern between haplotypes. Both markers denoted the absence of population differentiation (FST < 0) and the presence of high genetic flow with multiple migrants between colonies. Lack of genetic distinction between localities and high genetic diversity identified here may be attributed to a recent population expansion after the last glacial maximum. Although populations are currently stable, future monitoring of populations is advocated.