Harbor Porpoise: Phocoena phocoena

Abstract

This chapter discusses the characteristics, taxonomy, distribution, abundance, and ecology of the harbor porpoise or Phocoena phocoena. The harbor porpoise is a small odontocete inhabiting coastal temperate and boreal waters of the Northern Hemisphere. Harbor porpoises have a short, stocky body resulting in a rotund shape, an adaptation that helps them limit heat loss in the cold northern climes. The dorsal side of the harbor porpoise and the tail flukes are dark gray, almost black. The chin and underbelly are contrasting light gray, almost white. The head and sides are shaded gray, and darker gray stripes originate near the back of the mouth and run back toward the flippers, which are dark gray. Individual differences in the shading patterns occur. The porpoises in each of these ocean basins are reproductively isolated, resulting in division of the species into subspecies: Phocoena phocoena phocoena in the Atlantic Ocean and Phocoena phocoena vomerina in the Pacific Ocean. Most likely there is an additional, yet unnamed subspecies in the western North Pacific. The harbor porpoises of the Black Sea are classified as a separate subspecies Phocoena phocoena relicta. These subspecies differ from each other morphologically and genetically. Atlantic harbor porpoises have larger skulls but shorter jaws than Pacific harbor porpoises. Some morphological differences and variation in pigmentation are observed within the Atlantic Ocean porpoises.