Harbour Porpoise (Phocoena phocoena)
MammalMarinePorpoise
A harbour porpoise surfacing in Glacier Bay, Alaska.
Image: National Park Service, Public domain, via Wikimedia Commons.
Overview
The harbour porpoise (Phocoena phocoena) is a small, stocky porpoise of cool coastal and continental-shelf waters across the North Atlantic, the North Pacific and the Black Sea. It is usually seen alone or in small groups, and when it surfaces it rolls forward without splashing and normally shows little of its body.
It has a rounded head with a short, blunt beak and a triangular dorsal fin midway along the back, usually edged with small hard bumps. The back is dark gray, the sides lighter gray and the belly and throat white, with a dark chin patch and a dark stripe from the mouth to the flipper; males and females are colored alike. It rarely rides bow waves or leaps, and it usually avoids boats. In the North Pacific it can be confused with Dall's porpoise, which differs in its black-and-white pattern and its fin shape and tends to behave differently, rooster-tailing or raising its tail stock higher when it rolls.
Adults are mostly under 1.8 m long, with a maximum of about 2 m, and females are slightly larger than males. Adult length is also given as 141–163 cm in the North Atlantic, 1.5–2 m or 1.4–2 m, and adult weight as 45–65 kg or 45–70 kg in most accounts and 55–75 kg in one; another account gives 5 to 5.5 feet and 135 to 170 pounds without stating an age. Newborns are given as 65–75 cm, 70–90 cm or 70–100 cm long and as 5 kg, 6–8 kg or 6 to 10 kg in weight.
Habitat & Range
Harbour porpoises live mainly in cool coastal waters and over the continental shelf, typically less than 200 m deep, including bays, estuaries, harbors, fjords and river mouths. They sometimes travel over deeper offshore water and move up rivers — regularly by one account, sometimes by others: one was recorded about 55 km up British Columbia's Fraser River, and one account reports animals hundreds of kilometers from the sea. A species database gives a temperature range of 2–16 °C.
In the Atlantic they range from southern Baffin Island and West Greenland south to Cape Hatteras, North Carolina — less commonly to northern Florida — and from the Barents Sea to Senegal, but they do not enter Hudson Bay. In the Pacific they range from Japan and central California north to the Chukchi and Beaufort seas. One account recognizes four subspecies: P. p. phocoena in the North Atlantic, P. p. vomerina in the eastern North Pacific, an unnamed subspecies in the western North Pacific and P. p. relicta in the Black Sea, the Sea of Azov and the Sea of Marmara to the northern Aegean. In the Baltic, harbour porpoises are now mostly restricted to the Kattegat and Belt Sea.
Diet
Harbour porpoises eat mainly small schooling fish such as herring, mackerel, sprat and capelin, as well as sandeels, cod, hake and other fish, many of them bottom-dwelling, and some squid, octopus and shrimp. They are opportunistic, and their diet varies by area, season and year, yet porpoises in any one area tend to rely on two or three fish species; in the Gulf of St. Lawrence, capelin and herring made up more than 80% of the diet by mass. In one British Columbia study area, by contrast, market squid appeared to be the most important prey, and squid seem to matter more in British Columbia than elsewhere. Porpoises feed almost constantly, on around three thousand small fish a day.
Behavior
Harbour porpoises are usually seen alone or in small groups. Typical groups are given as two or three animals, fewer than five or six, fewer than eight, or pairs and groups of 5–10, and in European Atlantic surveys the mean group size was 1.35 from the air and 1.53 from ships. At times larger, loose groups form, mostly for feeding or, by one account, migration, with the largest gatherings reported as up to 100, up to 200 or several hundred animals. Cooperative foraging has not commonly been observed.
Seasonal shifts appear to be mostly between inshore and offshore waters, possibly influenced by prey and by ice-free water, and some populations move south or farther from shore to avoid ice; accounts differ on whether these movements amount to migration. Two females tagged in West Greenland and tracked for more than a year traveled over 17,500 km and 10,000 km, spending on average 83% of their time offshore over water deeper than 200 m before returning the next summer.
Human Interaction & Conservation
Harbour porpoises were historically hunted across much of their range for meat and blubber; in the North Atlantic NAMMCO area they are now hunted only in Greenland. Today bycatch — drowning in fishing nets, mainly gillnets — is the main threat in most areas, and in the Baltic, North and Irish seas and the northeast Atlantic several thousand drown in nets every year. Noise, pollution and overfishing are further threats.
They are protected in the United States under the Marine Mammal Protection Act of 1972 and in the UK under the Wildlife and Countryside Act 1981, and they are listed in CITES Appendix II. U.S. measures include seasonal gillnet restrictions, closures and acoustic deterrents called pingers, and in Norwegian trials pingers cut porpoise bycatch by 70–100%. IUCN's global assessment lists the harbour porpoise as Least Concern (2023).
Reproduction & Life Cycle
Females have one calf at a time. Most mating takes place in summer, and after an apparent delayed implantation of 6 or 7 weeks, gestation lasts 10 to 11 months; calves are born in late spring and summer, mostly from May to July or May to August, and from May to September in British Columbia. Females usually mature at 3 to 4 years, though age at maturity varies by region and may be as young as 2 or as old as 5 years.
In the North Atlantic most females produce a calf each year, and females in some stocks are likely to be pregnant and nursing at once, whereas off California females give birth only every second year. Lactation is given as 7 or 8 months, 8 or 9 months, or 8 to 12 months; calves may start taking solid food at around 5 months and stay with their mother for about 18 months. Harbour porpoises appear to hybridize regularly with Dall's porpoises in southern British Columbia.
The maximum recorded age, from tooth aging, is 24 years, but fewer than 5% of North Atlantic porpoises live beyond 12 years, and a modeling study puts longevity — defined as the 99th percentile of the age distribution — at 13 years. One account gives a lifespan of about 24 years without saying what it measures, another says it is believed to be 6 to 20 years, and a UK account gives an average lifespan of up to 20 years. One captive animal was still alive at 20.4 years.
Sourced facts
Each value below is traced to the specific reference that states it. Open a row's evidence to see the source, where to look in it, and how firmly it supports the value. Sources checked 2026-10-20.
| Fact | What the source states | Evidence |
|---|---|---|
| Distinguishing traits | Small, stocky porpoise with a rounded head, short blunt beak and a triangular dorsal fin midway along the back, usually edged with small hard bumps. Dark gray back, lighter gray sides, white belly and throat, dark chin patch and a dark stripe from mouth to flipper.Teeth are small and spade-shaped. Coloration does not differ between the sexes. At the surface it rolls forward without splashing and normally shows little of its body; it rarely rides bow waves or leaps and usually avoids boats. Dall's porpoise, which overlaps with it in the North Pacific, differs in its black-and-white pattern and fin shape and tends to behave differently, rooster-tailing or raising its tail stock higher when rolling. | Matches source · NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), North Atlantic Marine Mammal Commission (NAMMCO), Animal Diversity Web, University of Michigan Museum of Zoology, OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species), Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada — how we knowNOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
North Atlantic Marine Mammal Commission (NAMMCO)
Animal Diversity Web, University of Michigan Museum of Zoology
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
|
| Geographic range | Native to the North Atlantic, North Pacific and Black Sea. Atlantic: southern Baffin Island and West Greenland to Cape Hatteras, North Carolina, and the Barents Sea to Senegal. Pacific: Japan and central California north to the Chukchi and Beaufort seas.Less commonly south to northern Florida; does not enter Hudson Bay. One account recognizes four subspecies: P. p. phocoena (North Atlantic), P. p. vomerina (eastern North Pacific), an unnamed one (western North Pacific) and P. p. relicta (Black Sea, Sea of Azov and Sea of Marmara to the northern Aegean). In the Baltic it is now mostly restricted to the Kattegat and Belt Sea. One account also lists the Mediterranean region. | Matches source · NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), North Atlantic Marine Mammal Commission (NAMMCO), OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, Animal Diversity Web, University of Michigan Museum of Zoology, SeaLifeBase (FishBase Consortium), ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species), Mammal Diversity Database (American Society of Mammalogists) — how we knowNOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
North Atlantic Marine Mammal Commission (NAMMCO)
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
Animal Diversity Web, University of Michigan Museum of Zoology
SeaLifeBase (FishBase Consortium)
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
Mammal Diversity Database (American Society of Mammalogists)
|
| Habitat | Mainly cool coastal and continental-shelf waters, typically less than 200 m deep, including bays, estuaries, harbors, fjords and river mouths. It sometimes travels over deeper offshore waters and moves up rivers (regularly in one account, sometimes in others), occasionally far from the sea.One account gives waters less than 650 feet deep; in the eastern North Atlantic it is found mainly at depths of 20–200 m. One British Columbia record was about 55 km up the Fraser River, and one account reports animals hundreds of kilometers from the sea. A species database gives a temperature range of 2–16 °C. | Matches source · NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada, North Atlantic Marine Mammal Commission (NAMMCO), Animal Diversity Web, University of Michigan Museum of Zoology, ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species), OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, SeaLifeBase (FishBase Consortium) — how we knowNOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
North Atlantic Marine Mammal Commission (NAMMCO)
Animal Diversity Web, University of Michigan Museum of Zoology
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
SeaLifeBase (FishBase Consortium)
|
| Diet | Mainly small schooling fish such as herring, mackerel, sprat and capelin; also sandeels, cod, hake and other fish, many bottom-dwelling, and some squid, octopus and shrimp. Opportunistic: diet varies by area, season and year, though porpoises in one area tend to rely on two or three fish species.Prey come from both open-water and bottom habitats. In one British Columbia study area, market squid appeared to be the most important prey, with other prey including Pacific herring and Pacific hake; squid seem more important there than elsewhere. In the Gulf of St. Lawrence, capelin and herring made up more than 80% of the diet by mass. Porpoises feed almost constantly, on around three thousand small fish a day. | Matches source · NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species), North Atlantic Marine Mammal Commission (NAMMCO), Animal Diversity Web, University of Michigan Museum of Zoology, OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada — how we knowNOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
North Atlantic Marine Mammal Commission (NAMMCO)
Animal Diversity Web, University of Michigan Museum of Zoology
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
|
| Body size | Adults are mostly under 1.8 m long, with a maximum of about 2 m; adult length is also given as 141–163 cm, 1.5–2 m or 1.4–2 m, and length as 5 to 5.5 feet (age not stated). Females are slightly larger than males. Newborns measure 65–75 cm, 70–90 cm or 70–100 cm, by different accounts.sources disagreeWhere the measure is named it is total length. The 141–163 cm adult and 65–75 cm newborn figures are for the North Atlantic, where females are larger at all ages. In British Columbia porpoises are about 80–90 cm at birth and occasionally approach 2 m. A species database gives a maximum length of 200 cm. | Sources disagree · North Atlantic Marine Mammal Commission (NAMMCO), NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), Animal Diversity Web, University of Michigan Museum of Zoology, ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species), OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, The Wildlife Trusts (UK), Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada, SeaLifeBase (FishBase Consortium) — how we knowWhat each reading says
Adult length differs: 141–163 cm (North Atlantic) in one account, 5 to 5.5 feet (age not stated) in another, 1.5–2 m in a third and 1.4–2 m in a fourth, while two others say most adults are under 1.8 m. Newborn length is 65–75 cm in one account, 70–90 cm in two, 70–100 cm in another and about 80–90 cm in British Columbia. North Atlantic Marine Mammal Commission (NAMMCO)
NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
Animal Diversity Web, University of Michigan Museum of Zoology
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
The Wildlife Trusts (UK)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
SeaLifeBase (FishBase Consortium)
|
| Body mass | Adults weigh 45–65 kg or 45–70 kg in most accounts and 55–75 kg in one; another gives 135 to 170 pounds (age not stated). Newborns weigh 5 kg, 6–8 kg or 6 to 10 kg, by different accounts.sources disagreeOne account's figures (45–65 or 46–65 kg; newborns 6 to 10 kg) are for the North Atlantic, where females are larger than males at all ages. One database gives 70.0 kg as the maximum published weight; another lists averages of 52,500 g for adults and 7,000 g at birth. | Sources disagree · Animal Diversity Web, University of Michigan Museum of Zoology, North Atlantic Marine Mammal Commission (NAMMCO), ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species), OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, The Wildlife Trusts (UK), NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), SeaLifeBase (FishBase Consortium), AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources) — how we knowWhat each reading says
Adult weight ranges disagree: 45–65 kg in one account’s text but 45 to 60 kg in its data panel; 45–65 kg in another’s summary but 46–65 kg in its North Atlantic text; 45 to 70 kg in two accounts; 55–75 kg in another; and 135 to 170 pounds (age not stated) in another. Newborn weight is 5 kg, 6–8 kg or 6 to 10 kg. Animal Diversity Web, University of Michigan Museum of Zoology
North Atlantic Marine Mammal Commission (NAMMCO)
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
The Wildlife Trusts (UK)
NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
SeaLifeBase (FishBase Consortium)
AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources)
|
| Lifespan | Maximum recorded age 24 years (tooth aging); fewer than 5% live beyond 12 years (North Atlantic); modeled longevity 13 years. Lifespan is also given as about 24 years (measure not stated), believed 6 to 20 years, or an average of up to 20 years. Captivity: one still alive at 20.4 years.sources disagreeOne report says average longevity has not been determined. The modeled figure is the 99th percentile of the age distribution. Of 62 porpoises aged in British Columbia, the oldest was 10 years, and animals over 12 are rare in other populations; another account says they rarely live more than 13 years in the wild, and specimens living past 20 years are rarely found. A data panel lists an average wild lifespan of 13.0 years. The captive record rests on a small sample. | Sources disagree · North Atlantic Marine Mammal Commission (NAMMCO), Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada, NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), Animal Diversity Web, University of Michigan Museum of Zoology, AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources), OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, The Wildlife Trusts (UK) — how we knowWhat each reading says
General lifespan figures differ and may measure different things: about 24 years in one account, which does not name the measure and matches the recorded maximum; believed to be 6 to 20 years in another; and an average lifespan of up to 20 years in a third. North Atlantic Marine Mammal Commission (NAMMCO)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
Animal Diversity Web, University of Michigan Museum of Zoology
AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources)
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
The Wildlife Trusts (UK)
|
| Social structure | Usually alone or in small groups; larger, loose groups form at times, mostly for feeding or migration. Typical and maximum group sizes are reported differently, with the largest gatherings given as up to 100, up to 200 or several hundred animals.sources disagreeIn European Atlantic surveys, mean group size was 1.35 from the air and 1.53 from ships; near southern Vancouver Island groups ranged from 1 to 8, averaging 1.87. Cooperative foraging has not been commonly observed, and associations with other cetaceans are uncommon, some of them aggressive. | Sources disagree · NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), Animal Diversity Web, University of Michigan Museum of Zoology, ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species), North Atlantic Marine Mammal Commission (NAMMCO), OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada — how we knowWhat each reading says
Typical group size is two or three in two accounts, pairs or groups of 5–10 in another, fewer than eight in another, fewer than five or six in another and 1–8 in British Columbia. The largest aggregations are given as up to 100, up to 200, or several hundred animals. NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
Animal Diversity Web, University of Michigan Museum of Zoology
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
North Atlantic Marine Mammal Commission (NAMMCO)
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
|
| Reproduction | One calf at a time. Mating is mainly in summer; after an apparent delayed implantation of 6 or 7 weeks, gestation lasts 10 to 11 months, and calves are born in late spring and summer. Females usually mature at 3 to 4 years. Reported lactation lengths differ.sources disagreeBirths mostly May–July or May–August; May–September in British Columbia. Age at maturity varies by region and may be as young as 2 or as old as 5 years. In the North Atlantic most females produce a calf each year, and females in some stocks are likely to be pregnant and nursing at once; off California, females give birth only every second year. Calves may eat solids from about 5 months and stay with the mother about 18 months. Appears to hybridize regularly with Dall's porpoise in southern British Columbia. | Sources disagree · NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), North Atlantic Marine Mammal Commission (NAMMCO), Animal Diversity Web, University of Michigan Museum of Zoology, OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada, AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources), ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species) — how we knowWhat each reading says
Lactation is given as 7 or 8 months in one account, 8 or 9 months in another and 8 to 12 months in two others, and the average weaning age is 243 days in a life-history database. NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
North Atlantic Marine Mammal Commission (NAMMCO)
Animal Diversity Web, University of Michigan Museum of Zoology
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
AnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources)
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
|
| Movement | Seasonal shifts appear to be mostly inshore–offshore, possibly influenced by prey and ice-free water, and some populations move south or farther from shore to avoid ice. Accounts differ on whether this amounts to migration.sources disagreeTwo females tagged in West Greenland were tracked for more than a year, traveling over 17,500 km and 10,000 km and spending on average 83% of their time offshore over water deeper than 200 m before returning the next summer. Off western North America, several lines of evidence suggest limited movements. | Sources disagree · NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), Animal Diversity Web, University of Michigan Museum of Zoology, North Atlantic Marine Mammal Commission (NAMMCO), OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada — how we knowWhat each reading says
Two accounts describe some populations as migratory: one names those off the eastern United States and Canada, and the other says western Atlantic porpoises move far out to sea near the end of summer and return in spring. A third finds noticeable seasonal shifts in some locations but says these porpoises do not appear to undertake coordinated migrations. NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
Animal Diversity Web, University of Michigan Museum of Zoology
North Atlantic Marine Mammal Commission (NAMMCO)
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
Committee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada
|
| Human interaction | Historically hunted across much of its range for meat and blubber; in the North Atlantic NAMMCO area it is now hunted only in Greenland. Bycatch, mainly in gillnets, is the main threat in most areas. Protected by U.S. and UK law and listed in CITES Appendix II.One account notes that its meat is eaten and its oil used in lamps and as a lubricant. Laws named include the U.S. Marine Mammal Protection Act of 1972 and the UK Wildlife and Countryside Act 1981. Noise, pollution and overfishing are further threats. Several thousand drown in fishing nets each year in the Baltic, North and Irish seas and northeast Atlantic. U.S. measures include seasonal gillnet restrictions, closures and acoustic 'pingers'; in Norwegian trials pingers cut porpoise bycatch by 70–100%. | Matches source · North Atlantic Marine Mammal Commission (NAMMCO), Animal Diversity Web, University of Michigan Museum of Zoology, NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration), ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species), OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University, The Wildlife Trusts (UK) — how we knowNorth Atlantic Marine Mammal Commission (NAMMCO)
Animal Diversity Web, University of Michigan Museum of Zoology
NOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)
ASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)
OBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University
The Wildlife Trusts (UK)
|
| Conservation status | Least Concern (LC), global assessment, 2023 | Matches source · IUCN Red List of Threatened Species — how we knowIUCN Red List of Threatened Species
|
References for the facts above
- GovernmentNOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration)Supports: identification, range, habitat, diet, body size, body mass, lifespan, social structure, reproduction, movement, human interaction. Retrieved 2026-10-20.Limitations: Species directory page last updated 04/07/2026; its stock, population and management text covers U.S. stocks only. Quick Facts give weight, length and 'Lifespan About 24 years' without saying whether these are typical or maximum values, or for which sex, region or sample.
- UniversityAnimal Diversity Web, University of Michigan Museum of ZoologySupports: identification, range, habitat, diet, body size, body mass, lifespan, social structure, reproduction, movement, human interaction. Retrieved 2026-10-20.Limitations: Student-authored account dated 2000-02-17 (citing sources up to 2001). It is internally inconsistent on adult mass (45-65 kg in the text, 45 to 60 kg in the data panel). Its 'IUCN Red List Critically Endangered' tag is an evident error and is not used; its statement that returning migrants are territorial is supported by no other account and is not used.
- GovernmentNorth Atlantic Marine Mammal Commission (NAMMCO)Supports: identification, range, habitat, diet, body size, body mass, lifespan, social structure, reproduction, movement, human interaction. Retrieved 2026-10-20.Limitations: Intergovernmental commission's species page, 'Latest update: July 2021'; the account deals with the North Atlantic subspecies (P. p. phocoena) and cites regional studies. Its summary gives adult mass as 45-65 kg but its text gives 46-65 kg. Its summary's Greenland catch of 'around 2,500' a year (NAMMCO 2015) is below the 2021-2024 totals in its own catch table (3,855-4,355), so no catch figure is used.
- GovernmentASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species)Supports: identification, range, habitat, diet, body size, body mass, social structure, reproduction, human interaction. Retrieved 2026-10-20.Limitations: Undated, unreferenced species page of an intergovernmental agreement; its bycatch figure refers to the agreement area in European waters. The header's 'IUCN Status: Critically endangered' refers to the Baltic Sea subpopulation, as its text explains, and is not used. The same text appears on the CMS species page (cms.int/species/phocoena-phocoena), which is therefore not cited separately.
- UniversityOBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke UniversitySupports: identification, range, habitat, diet, body size, body mass, lifespan, social structure, reproduction, movement, human interaction. Retrieved 2026-10-20.Limitations: Undated species profile whose references run to 2003; its statement that the IUCN classifies the species as vulnerable and its U.S. stock estimates from 1990s surveys are outdated and not used.
- ReferenceSeaLifeBase (FishBase Consortium)Supports: range (distribution by subspecies), habitat (temperature range), body size and body mass (maxima). Retrieved 2026-10-20.Limitations: Database summary; its maximum length and weight are credited to the 1993 FAO identification guide (Jefferson, Leatherwood and Webber, its Ref. 1394), and the temperature range to its Ref. 75906. The length field is labeled 'male/unsexed'.
- ReferenceAnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources)Supports: lifespan, body mass and reproduction (life-history averages). Retrieved 2026-10-20.Limitations: Build 15 (03/07/2023). The 20.4-year captive maximum is rated small sample size, acceptable data quality; the wild statement cites Nowak (1999); the life-history figures are averages not tied to a population.
- GovernmentCommittee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of CanadaSupports: habitat (depth, river record), reproduction (hybridization with Dall's porpoise). Retrieved 2026-10-20.Limitations: Executive summary of the 2003 update status report on the Pacific Ocean population (British Columbia); page details dated 2018-01-02. Figures refer to British Columbia unless stated.
- GovernmentCommittee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of CanadaSupports: identification, body size, social structure (British Columbia). Retrieved 2026-10-20.Limitations: Species-information chapter of the same 2003 British Columbia report; it names three subspecies and omits the Black Sea form.
- GovernmentCommittee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of CanadaSupports: diet, lifespan, social structure, reproduction, movement. Retrieved 2026-10-20.Limitations: General-biology chapter of the same 2003 British Columbia report; diet figures come from 26 stomachs from southern British Columbia and ages from 62 aged specimens.
- Wildlife referenceThe Wildlife Trusts (UK)Supports: body size, body mass, lifespan, human interaction (UK protection). Retrieved 2026-10-20.Limitations: Conservation charity's UK species page; its 'Statistics' (length, weight, 'Average Lifespan: up to 20 years') give no source, sex or sample. Its visitor advice is not used.
- ReferenceMammal Diversity Database (American Society of Mammalogists)Supports: identity (accepted name, authorship, classification, synonyms, other common names); range summary. Retrieved 2026-10-20.Limitations: Taxonomic record; its one-line distribution is used to corroborate range only.
- ReferenceIUCN Red List of Threatened SpeciesSupports: The global Red List category and the year of the assessment. Retrieved 2026-10-20.Limitations: Read from the Red List export IUCN publishes to GBIF; iucnredlist.org itself does not answer automated reads. Categories are reassessed over time.
Frequently Asked Questions — Harbour Porpoise
How big is a harbour porpoise?
Adults are mostly under 1.8 m long, with a maximum of about 2 m, and weigh 45–65 kg or 45–70 kg in most accounts. Females are slightly larger than males.
What do harbour porpoises eat?
Mainly small schooling fish such as herring, mackerel, sprat and capelin, along with sandeels, cod, hake, squid, octopus and shrimp. They feed almost constantly, on around three thousand small fish a day.
What is the main threat to harbour porpoises?
Bycatch — drowning in fishing nets, mainly gillnets — is the main threat in most areas. Several thousand drown in nets each year in the Baltic, North and Irish seas and the northeast Atlantic.
How long do harbour porpoises live?
The maximum recorded age is 24 years, but fewer than 5% of North Atlantic porpoises live beyond 12 years, and a modeling study puts longevity, defined as the 99th percentile of the age distribution, at 13 years.
Sources and further reading
Authoritative wildlife references used for general educational context. Conservation status should always be verified against current IUCN Red List data. External links open in a new tab.
- GovernmentNOAA Fisheries (National Marine Fisheries Service, U.S. National Oceanic and Atmospheric Administration) — Harbor porpoise species page — identification, range, habitat, diet, body size, body mass, lifespan, social structure, reproduction, movement, human interaction
- UniversityAnimal Diversity Web, University of Michigan Museum of Zoology — Phocoena phocoena (harbor porpoise) species account — identification, range, habitat, diet, body size, body mass, lifespan, social structure, reproduction, movement, human interaction
- GovernmentNorth Atlantic Marine Mammal Commission (NAMMCO) — Harbour porpoise (North Atlantic Marine Mammal Commission) — identification, range, habitat, diet, body size, body mass, lifespan, social structure, reproduction, movement, human interaction
- GovernmentASCOBANS (Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas, under the UN Convention on Migratory Species) — Harbour porpoise (ASCOBANS) — identification, range, habitat, diet, body size, body mass, social structure, reproduction, human interaction
- UniversityOBIS-SEAMAP, Marine Geospatial Ecology Lab, Duke University — Phocoena phocoena species profile (OBIS-SEAMAP) — identification, range, habitat, diet, body size, body mass, lifespan, social structure, reproduction, movement, human interaction
- ReferenceSeaLifeBase (FishBase Consortium) — Phocoena phocoena species summary — range (distribution by subspecies), habitat (temperature range), body size and body mass (maxima)
- ReferenceAnAge: The Animal Ageing and Longevity Database (Human Ageing Genomic Resources) — Phocoena phocoena longevity entry — lifespan, body mass and reproduction (life-history averages)
- GovernmentCommittee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada — COSEWIC 2003 report, harbour porpoise (Pacific Ocean population): executive summary — habitat (depth, river record), reproduction (hybridization with Dall's porpoise)
- GovernmentCommittee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada — COSEWIC 2003 report, harbour porpoise (Pacific Ocean population): species information — identification, body size, social structure (British Columbia)
- GovernmentCommittee on the Status of Endangered Wildlife in Canada (COSEWIC), Species at Risk Public Registry, Government of Canada — COSEWIC 2003 report, harbour porpoise (Pacific Ocean population): biology — diet, lifespan, social structure, reproduction, movement
- Wildlife referenceThe Wildlife Trusts (UK) — Harbour porpoise (The Wildlife Trusts) — body size, body mass, lifespan, human interaction (UK protection)
- ReferenceMammal Diversity Database (American Society of Mammalogists) — Phocoena phocoena (Mammal Diversity Database) — identity (accepted name, authorship, classification, synonyms, other common names); range summary
- ReferenceIntegrated Taxonomic Information System (ITIS) — Phocoena phocoena (harbour porpoise) — identity cross-check: valid name, TSN 180473, synonym, three subspecies, class Mammalia, order Cetacea
- ReferenceSociety for Marine Mammalogy, Committee on Taxonomy (List of Marine Mammal Species and Subspecies) — Phocoena phocoena (harbour porpoise) — identity cross-check: species and three subspecies, order Artiodactyla with infraorder Cetacea
- ReferenceIUCN Red List — Phocoena phocoena assessment — The global Red List category and the year of the assessment