Sperm whale population structure in the eastern and central North Pacific inferred by the use of single nucleotide polymorphisms (SNPs), microsatellites and mitochondrial DNA

We use mitochondrial DNA (400bp), six microsatellites and 36 single nucleotide polymorphisms (SNPs), 20 of which were linked, to investigate population structure of sperm whales (Physeter macrocephalus) in the eastern and central North Pacific. SNP markers, reproducible across technologies and laboratories, are ideal for long-term studies of globally distributed species such as sperm whales, a species of conservation concern due to both historical and contemporary impacts. We estimate genetic differentiation among three strata in the temperate to tropical waters where females are found: California Current, Hawai‛i and the eastern tropical Pacific. We then consider how males on sub-Arctic foraging grounds assign to these strata. The California Current stratum was differentiated from both the other strata (p<0.05) for mtDNA, microsatellites and SNPs, suggesting that the region supports a demographically independent population and providing the first indication that males may exhibit...