Harbor Porpoise

Harbor porpoise (Phocoena phocoena) are the smallest of 22 cetaceans recorded in the Salish Sea and are probably one of the few that are resident year-­â€round. Excluding the Arctic, their distribution extends throughout the Northern Hemisphere. Their numbers in the waters of Puget Sound declined steeply in the 1970s, but their population has increased in recent years.

With a population growth of about 10 percent per year in inland waters, harbor porpoises are having an undetermined but growing effect on food dynamics in Puget Sound. (Source:

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.

Harbor porpoises were once common in Puget Sound, but had all but disappeared from local waters by the 1970s. Regular and numerous anecdotal sightings in recent years show that populations of these cetaceans are now increasing and may be approaching their former status. The attached document from NOAA Fisheries describes harbor porpoise numbers and their geographic range in Puget Sound as of 2011.

Antibiotic Resistance of Bacteria in Two Marine Mammal Species, Harbor Seals and Harbor Porpoises, Living in an Urban Marine Ecosystem, the Salish Sea, Washington State, Usa

Harbor seals and harbor porpoises in the Salish Sea are showing a relatively high presence of antibiotic-resistant bacteria. A 2021 paper in the journal Oceans suggests that these findings may indicate a wider problem among other species in the region.

A 2017 paper in the journal Marine Mammal Science examines harbor porpoise group structure and site fidelity in the Salish Sea.