Species: Phocoenoides dalli

Dall’s porpoises have declined in the Salish Sea since the early 1990s for reasons that are unknown. However, the species, which remains abundant in inshore waters of Alaska and in open coastal and offshore waters of the North Pacific Ocean, is not considered threatened or endangered. Major threats to Dall’s porpoise populations include direct hunting, by-catch in fisheries, and the impacts of environmental contaminants.

Puzzling encounters between endangered killer whales and harbor porpoises point to questions about prey availability and whale culture, scientists say. Are the whales playing, practicing their hunting skills, or is something else going on? 

The mysterious practice of killing porpoises may have a useful function, but it has yet to be fully explained, according to orca researcher Deborah Giles.

In the 1940s, harbor porpoise were among the most frequently sighted cetaceans in Puget Sound, but by the early 1970s they had all but disappeared from local waters. Their numbers have since increased, but they remain a Species of Concern in the state of Washington. This in-depth profile looks at harbor porpoise in the Salish Sea, and was prepared by the SeaDoc Society for inclusion in the Encyclopedia of Puget Sound. 

A 2014 paper in Endangered Species Research suggests that harbour porpoises inhabiting coastal waters of southern British Columbia constitute a single genetic population, which should be reflected in management decisions.