Harbor porpoise in the Gulf of Maine. Credit: NOAA Fisheries/Northeast Fisheries Science Center.
Harbor porpoise in the Gulf of Maine. Credit: NOAA Fisheries/Northeast Fisheries Science Center.
About the Species
Harbor porpoise in the Gulf of Maine. Credit: NOAA Fisheries/Northeast Fisheries Science Center.
Harbor porpoise in the Gulf of Maine. Credit: NOAA Fisheries/Northeast Fisheries Science Center.
The harbor porpoise is a shy animal, most often seen in groups of two or three. They prefer coastal areas and are most commonly found in bays, estuaries, harbors, and fjords. Because they prefer coastal habitats, harbor porpoises are particularly vulnerable to gillnets and fishing traps, pollution, and other types of human disturbance, such as underwater noise.
Harbor porpoises in the United States are not endangered or threatened. Like all marine mammals, they are protected under the Marine Mammal Protection Act.
NOAA Fisheries helps conserve the harbor porpoise through collaborative management, integrated science, partnerships, and outreach. Our scientists use a variety of innovative techniques to study, protect, and rescue harbor porpoises in distress (e.g., disentanglement and stranding response). Our work helps reduce harmful effects of human activities such as fisheries interactions, noise, and pollution, through effective management actions based on sound science, public input, and public outreach.
Population Status
NOAA Fisheries estimates population size for each stock of harbor porpoises in its stock assessment reports. A stock is a group of animals that occupy the same area and interbreed. Population trends for many of the U.S. stocks are unknown.
Appearance
Harbor porpoises have a small, robust body with a short, blunt beak and a medium-sized triangular dorsal fin. Their back is dark gray fading to lighter intermediate shades of gray on their sides. Their belly and throat are white, with a dark gray chin patch. Females are slightly larger than males.
Behavior and Diet
Harbor porpoises mainly eat schooling fish, like herring and mackerel. Occasionally, they will eat squid and octopus.
They are most often seen singly, in pairs, or in groups of up to 10, although there are reports of aggregations of up to 200 harbor porpoises. Most seasonal movements appear to be inshore-offshore and may be influenced by prey availability or the presence of ice-free waters.
Unlike most other porpoises, they do not approach boats to bow ride and can be very shy, avoiding surfacing near boats. When surfacing for air, they do not splash. They roll from beak to fluke and arch their backs.
Where They Live
Harbor porpoises live in northern temperate and subarctic, and arctic coastal and offshore waters. They are commonly found in bays, estuaries, harbors, and fjords less than 650 feet deep. In the North Atlantic, they range from West Greenland to Cape Hatteras, North Carolina (but do not enter Hudson Bay), and from the Barents Sea to West Africa. In the North Pacific, they are found from Japan north to the Chukchi Sea and from Point Conception off Central, California North to the Beaufort Sea.
World map providing approximate representation of the Harbor porpoise's range.
Lifespan & Reproduction
Females reach sexual maturity at 3 to 4 years and may give birth every year for several years in a row. Gestation lasts for 10 to 11 months and lactation lasts for 8 to 12 months.
Little is known of their reproductive biology. Most mating occurs in summer and most births occur between May and July.
Threats
Entanglement
One of the main threats to harbor porpoises is getting caught in fishing gear. They can become entangled or captured in commercial fishing gear such as gillnets, trawls, and herring weirs.
Ocean Noise
Underwater noise pollution interrupts the normal behavior of harbor porpoises and interferes with their communication.
Scientific Classification
| Animalia |
Chordata |
Mammalia |
Cetacea |
Phocoenidae |
Phocoena |
phocoena |
Last updated by NOAA Fisheries on 09/15/2022
