VARIABILITY OF THE MITOCHONDRIAL CONTROL REGION IN POPULATIONS OF THE HARBOR PORPOISE, PHOCOENA-PHOCOENA, ON INTEROCEANIC AND REGIONAL SCALES

The harbour porpoise, Phocoena phocoena, experiences a high degree of incidental mortality owing to interactions with commercial fisheries. To properly manage the species, it is necessary to assess levels of inter- and intra-populational variation so that management units can be accurately defined. A portion of the mitochondrial DNA control region was amplified and sequenced to characterize the amount of genetic variation within harbour porpoise populations in the Northeast Pacific, North Atlantic, and Black Sea. In addition, the utility of the control region to discriminate among putative populations of harbour porpoises along the west coast of North America was investigated. The resultant data were analyzed phylogenetically using a neighbor-joining algorithm and statistically for population subdivision using an analysis of variance approach. No shared haplotypes were found among the three ocean basins, and the estimated sequence divergence among them was high. Within the Northeast Pacific, several distinct groupings of haplotypes were found, but no phylogenetic concordance between sequence type and geographic location was found. However, differences in the geographic distributions among and genetic diversity within matrilineal groups, and indications of significant genetic heterogeneity among the sampling locales in the Northeast Pacific argue for management strategies on a regional basis.