Harbor porpoises have a small, robust body with a short, blunt beak. Females are slightly larger than males.
They have a medium-sized triangular dorsal fin. Their back is dark gray while their belly and throat are white. They have a dark gray chin patch and also intermediate shades of gray along their sides.
Females reach sexual maturity at 3-4 years and may give birth every year for several years in a row. Gestation lasts for 10-11 months and lactation lasts for 8 to 12 months.
They feed on demersal and benthic species, mainly
schooling fish and cephalopods.
|135-170 pounds (61-77 kg)|
|5-5.5 feet (1.5-1.7 m)|
|dark gray with white underside|
|about 24 years|
|herring, capelin, and cephalopods|
|non-social animals usually seen in groups of 2 to 5 animals;
when surfacing for air, they do not splash, but roll from beak to fluke and arch their backs
RELATIVE SPECIES: Vaquita, Burmeister’s porpoise, Spectacled porpoise.
OTHER NAMES: “Puffers”
NEIGHBORING SPECIES: Dall’s porpoise, Short beaked common dolphin, killer whale.
PREDATORS: Humans, large whales, killer whales
THREATS: Trapped in fishing nets.
DIET: Herring, capelin, sprat, silver hake, squid and octopus.
MANNER OF FEEDING: Forage alone near the sea floor. Fishermen call them “herring hogs”.
BEHAVIOR: Solitary or in small groups, usually seen in larger groups towards the end of the summer. Sometimes leaps clear out of the water. Will roll at the surface in order to breathe. Will avoid boats and vessels.
REPRODUCTION: Females reach sexual maturity at age 3-4 years. Females will have a calf every year for several years in a row. This means they are pregnant and lactating at the same time. Breeding occurs briefly in the late spring. Gestation is 10-11 months. Calves are nursed for 8-12 months.
LIFE SPAN: 24 years
Harbor porpoises inhabit northern temperate and subarctic coastal and offshore waters. They are commonly found in bays, estuaries, harbors, and fjords less than 650 ft (200 m) deep.
Harbor porpoises have a discontinuous distribution. In the North Atlantic, they range from West Greenland to Cape Hatteras, NC (but do not enter Hudson Bay), and from the Barents Sea to West Africa. In the North Pacific, they are found from Japan (34°N) north to the Chukchi Sea and from Monterey Bay, CA to the Beaufort Sea.
NMFS Stock Assessment Reports (SARs) include estimated population sizes for U.S. stocks.
- “bycatch” in fishing gear, specifically in gillnets and trawls as well as herring weirs (in Canada)
In 1996, NMFS convened two “take” reduction teams (TRT) to mitigate bycatch of harbor porpoises in gillnet fisheries: the Gulf of Maine Harbor Porpoise TRT and the Mid-Atlantic TRT. The Gulf of Maine TRT addresses gillnet fisheries in waters from Maine through Rhode Island and theMid-Atlantic TRT addresses waters from the Connecticut/ New York border through the North Carolina/ South Carolina border. The teams submitted draft take reduction plans to NMFS, and we finalized the plans in 1998.
The Harbor Porpoise Take Reduction Plan (HPTRP) requires commercial fishermen to use pingers in gillnets in designated times and areas. There are also times and areas where gillnet fishing activities are prohibited. The HPTRT continues to meet to monitor the progress of the take reduction plans in achieving the MMPA long-term goal of reducing harbor porpoise bycatch to a zero mortality and serious injury rate.
In July 2009, NMFS proposed to amend the regulations implementing the HPTRP [pdf] (74 FR 36058) to address the increased incidental mortality and serious injury of the Gulf of Maine/ Bay of Fundy stock of harbor porpoises in gillnet fisheries throughout the stock’s U.S. range. The rule was finalized in February 2010 (75 FR 7383).
This species is protected under the Marine Mammal Protection Act of 1972 as amended.
- Their name is derived from the Latin word for pig (porcus) and are sometimes called “puffing pigs.”
- Harbor porpoises are most commonly found in bays, estuaries, harbors, and fjords.
- When surfacing for air, they do not splash; they roll from beak to fluke and arch the back