QuestionHarbor porpoise
Where Do Harbor Porpoises Live? North Atlantic and Pacific
Harbor porpoises live in cool, shallow coastal seas of the Northern Hemisphere: the North Atlantic from northwest Africa to Norway and from North Carolina to Greenland, the North Pacific from Japan to Alaska and California, and the North Sea, Baltic and Black Sea. Most stay in water less than 200 m (650 ft) deep.
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Harbor porpoise range at a glance
The harbor porpoise has a wide but patchy range. It is split into regional populations that rarely mix, and scientists recognize several subspecies: one in the North Atlantic, one in the Black Sea and at least one in the North Pacific.
| Region | Where harbor porpoises live | Notes |
|---|---|---|
| Northeast Atlantic | Barents Sea and Norway to Britain, Ireland, France, Iberia and northwest Africa | Densest in the southern North Sea and Danish waters |
| Baltic Sea | Western Baltic and Danish straits; very few in the central Baltic | Central Baltic group Critically Endangered |
| Northwest Atlantic | West Greenland, Newfoundland, Gulf of St. Lawrence, Bay of Fundy and Gulf of Maine | Some move south to North Carolina in winter |
| North Pacific | Japan and Russia to the Bering Sea, Alaska, British Columbia, Washington, Oregon and California | Southern limit near Point Conception, California |
| Black Sea | Black Sea and Sea of Azov | Separate subspecies, listed as Endangered |
Harbor porpoises are absent from the Southern Hemisphere and almost absent from the Mediterranean. They also avoid sea ice, so they do not enter Hudson Bay and leave much of the northern Baltic in winter.
Why do harbor porpoises stay near the coast?
The name says it all: harbor porpoises prefer bays, estuaries, fjords, sounds and harbors, and the open water of the continental shelf. Shallow coastal seas are rich in the small fish they eat, such as herring, sprat, sandeels and young cod, and much of their hunting happens near the seabed.
Their small body is another reason. A porpoise loses heat quickly in cold water and has little room to store energy, so it must eat almost constantly. Staying where food is dense and easy to reach makes sense. Porpoises sometimes follow fish far into estuaries and even up large rivers, but they always return to the sea.
North Sea and Baltic Sea porpoises
Europe is the heart of the harbor porpoise’s range. A large survey in 2016 estimated about 467,000 harbor porpoises in European Atlantic waters, from Gibraltar to northern Norway, with the highest numbers in the southern North Sea and around Denmark. Porpoises are regularly seen from the coasts of the Netherlands, Germany and Denmark, and in the Wadden Sea.
The Baltic Sea tells a different story. A healthy population lives in the western Baltic and the Danish straits, but the central Baltic, roughly east of the Danish island of Bornholm, holds only about 500 animals. This isolated group, which breeds on offshore banks south of the Swedish island of Gotland, is listed as Critically Endangered. In Britain, porpoises are the most common cetacean, and several marine protected areas have been created for them, including a large site in the southern North Sea.
Harbor porpoises in North America
On the Atlantic coast, harbor porpoises live from West Greenland and Newfoundland south through the Gulf of St. Lawrence to the Bay of Fundy and the Gulf of Maine. In summer they gather in the Bay of Fundy and the northern Gulf of Maine. In winter they spread out along the coast from Maine to New Jersey, and a few reach North Carolina.
On the Pacific coast, they range from the Bering and Chukchi seas through Alaska and British Columbia to Washington, Oregon and California, as far south as Point Conception. After sharp declines in the 20th century, porpoises have made a comeback in the inland waters of Washington state. Since the late 2000s they have also returned to San Francisco Bay, where they can be watched from the Golden Gate Bridge.
Why are harbor porpoises hard to see?
Even where they are common, harbor porpoises are easy to miss. They are small, about 1.4–1.9 m (4.6–6.2 ft) long, with a low triangular fin. They surface with a quick roll that shows only a dark back and fin for a second or two, rarely splash and almost never leap.
They are also shy. Unlike many dolphins they do not ride the bow waves of boats and usually move away from engines. The best way to find them is to watch from a headland on a calm, flat day, scanning for small fins, and to listen for the short “puff” of their breath. Learn the differences from dolphins in dolphin vs porpoise, or find good viewpoints in our guide to the wildlife of Scotland.
Threats where they live
Living close to the coast brings porpoises into contact with people. The biggest threat is bycatch: porpoises drown when they become tangled in gillnets set on the seabed. Thousands die this way each year in the North Atlantic, the Baltic and the Black Sea. Noise from ships, seismic surveys and the construction of offshore wind farms can push them out of important feeding areas for days.
Pollution and changes in prey add to the pressure. The fate of the vaquita, a close relative that lives only in Mexico’s Gulf of California, shows how dangerous gillnets can be for small porpoises with a limited range. Read more in why is the vaquita almost extinct?
Frequently asked questions
Are there harbor porpoises in the UK?
Yes. The harbor porpoise is the most common whale, dolphin or porpoise in British waters. It is seen all around the coast, especially off west Wales, Cornwall, western Scotland, the Hebrides, Shetland and in the southern North Sea.
Do harbor porpoises live in the Mediterranean?
Almost not. Harbor porpoises are essentially absent from the Mediterranean Sea itself. A separate subspecies lives in the Black Sea, and some of those animals reach the northern Aegean Sea through the Turkish straits.
Do harbor porpoises live in fresh water?
No. They are marine animals, but they often feed in brackish estuaries and occasionally swim far up large rivers. These trips are temporary, and porpoises cannot live permanently in fresh water.
Do harbor porpoises migrate?
Not in the way large whales do. Most move inshore and offshore with the seasons, following prey or avoiding ice. In the western Atlantic, porpoises from the Bay of Fundy and Gulf of Maine spread south in winter, some as far as North Carolina.
Are there harbor porpoises in the Southern Hemisphere?
No. Harbor porpoises live only in the Northern Hemisphere. Other porpoises take their place farther south, such as Burmeister's porpoise off South America and the spectacled porpoise in the cold waters of the Southern Ocean.
Can you see harbor porpoises in San Francisco Bay?
Yes. After being absent for decades, harbor porpoises have been seen regularly inside San Francisco Bay since the late 2000s. They often feed in the strong currents near the Golden Gate Bridge.
Sources and further reading
- NOAA Fisheries, "Harbor Porpoise"
- IUCN Red List of Threatened Species, "Phocoena phocoena"
- Animal Diversity Web (University of Michigan), "Phocoena phocoena"
Cite this page
“Where Do Harbor Porpoises Live? North Atlantic and Pacific.” Animal Atlas, https://animals.bigworldlist.com/questions/where-do-harbor-porpoises-live/.
