Harbor Porpoise

Harbor Porpoise

The harbor porpoise is a very small cetacean with a robust body. Their bodies are dark on the back and light underneath. Harbor porpoises are not social and are often shy and elusive around people.


Harbor porpoises live in shallow coastal waters in the North Atlantic, North Pacific and Black Sea.  Around the Pacific Northwest, harbor seals can be seen from all sites along The Whale Trail in Puget Sound, the Strait of Georgia and the Strait of Juan de Fuca.


Harbor porpoises have a rounded snout with a thick midsection.  Females are sexually mature at 3 – 4 years of age and can give birth once a year for several years.  Their gestation period is about 10 – 11 months and they nurse their young for up to a year.  Harbor porpoises eat small fish such as herring and capelin and squid.

Social Structure and Behavior

When harbor porpoises surface out of the water to breathe they do not make a slash; instead they arch their backs and roll their bodies gently through the water.  They sometimes travel alone or in small groups of about six individuals.  Very occasionally they have been spotted feeding together in groups as large as one hundred.

Current and Historical Threats

The biggest threat to harbor porpoises is “bycatch”, or accidentally being caught in gillnets and trawls. Special precautions have been put in place to reduce bycatch.  Harbor porpoises have also been hunted for centuries and are not as numerous as they once were.

Learn More!

Porpoises (WorldLifeLibrary) by AndrewJ. Read, 1999

Dolphins & Porpoises (Zoobooks) by BethWagnerBrust, 2003





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  1. Barbara Schaad-Lamph : 24 November 2013 4:11PM

    While kayaking on Sunday, Nov 24, at 3:30 pm off of Manchester, we saw a group of 5-6 harbor porpoises feeding by us. They were so close we could hear their blows as they surfaced. Super cool!

    • donna : 24 November 2013 4:24PM

      Hi Barbara – Thanks for the report, and lucky you! What a great Sunday sighting. Harbor porpoise are making a comeback in Puget Sound – good summary in this Seattle Times article by Lynda Mapes. Thanks for letting us know – send or upload pictures if you have any to share! Donna (for The Whale Trail)

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Adult ♂ : 5 ft (1.5 m)

Adult ♀ : 5.5 ft (1.7 m)

Birth Length :27 to 35 inches (70 to 90 cm)


Adult ♂ : 130 pounds (60 kg)

Adult ♀ : 130 pounds (60 kg)

Birth Weight : 14 to 22 pounds (6.4 to 10 kg)

Life Expectancy

24 years


The Whale Trail is a nonprofit organization in partnership with
Partners NOAA Seattle Aquarium People for Puget Sound Washington Department of Fish and Wildlife The Whale Museum National Marine Sanctuaries