Genetic diversity and population structure among northern bottlenose whales, Hyperoodon ampullatus, in the western North Atlantic Ocean

To assess population structure and genetic diversity among northern bottlen ose whales (Hyperoodon ampullatus), we compared mitochondrial DNA control r egion sequences from three populations in the western North Atlantic Ocean. Skin-biopsy samples were collected from animals in the Gully off Nova Scot ia, Canada, in 1996 and 1997 (n = 20), and teeth were obtained from whales taken in Davis Strait off northern Labrador (n = 20) and off northern Icela nd (n = 5) between 1967 and 1971 by the historical Norwegian fishery. Only low levels of genetic diversity were found among the 45 animals sampled (th ree polymorphic sites over 434 base pairs defining four haplotypes; haploty pe diversity (h) = 0.57, nucleotide diversity (pi) = 0.0015). The cause of this low variability is unclear but may be due to a possible bottleneck eve nt associated with the last glaciation. The distribution of mitochondrial D NA haplotypes between the Gully and Davis Strait populations was suggestive of regional differentiation (F-ST = 0.118, P = 0.024; Phi(ST) = 0.145, P = 0.007). Animals taken off northern Iceland were not included in statistica l analyses of population structure, owing to the small sample size. These d ata, in conjunction with other information collected to date, indicate that the Gully and Davis Strait populations should be considered separate stock s for management purposes.