Harbor Seal

Scientific Classification

Common Name

harbor seal or common seal

Kingdom

Animalia

Phylum

Chordata

Class

Mammalia

Order

Pinnipedia

Family

Phocidae

Genus Species

Phoca vitulina
There are 5 commonly recognized subspecies of harbor seals: Phoca vitulina richardii, the Eastern Pacific harbor seal; P. v. stejnegeri, the Kuril seal or Western Pacific harbor seal; P. v. vitulina, the Eastern Atlantic harbor seal; P. v. concolor the Western Atlantic harbor seal; and P. v. mellonae, the Ungava seal or Seal Lake seal. Berta and Churchill (2011) recognized only one subspecies in the North Pacific (P. v. richardii) and one in the North Atlantic (P. v. vitulina).

Fast Facts

Description

Harbor seals have a rounded head with a fairly blunt snout and, like other true seals, lack external ear pinnae. They exhibit a wide range of color variations, from silver with black spots, to black with gray or white rings, to almost pure white.
Male:Adult males are slightly larger than adult females

Size

Male:  1.6 to 1.9 m (5.2 to 6.2 ft) 
Female:  1.5 to 1.7 m (4.9 to 5.5 ft.)

Weight

Male: as much as 170 kg (375 lbs.)
Female: Up to 1.7 m (5.6 ft)

Diet

Harbor seals are generalist feeders that take a wide variety of fish, cephalopods, and crustaceans obtained from surface, mid-water, and benthic habitats. Their diet is highly varied, and animals from different populations and areas show differences, and there is also variation associated with seasonal and interannual changes in the abundance of prey.

Gestation

Gestational period 9 to 11 months; with 1.5 to 3 months delayed implantation; at birth, harbor seal pups are about 756 to 100 mm (29.5 to 39.4 in.) in length; newborn harbor seal pups weigh from 8 to 12 kg (8 to 26 lbs.)

Estral Period

Females come into estrus about a month after giving birth

Nursing Duration

Pups are suckled for an average of 26 days. Nursing may last as long as 6 weeks.

Sexual Maturity

Male:  4 to 6 years
Female:  3 to 5 years

Life Span

Longevity is about 30 to 35 years with females living longer than males.

Range

Harbor Seals are one of the most widespread of the pinnipeds. They are found throughout coastal waters of the Northern Hemisphere, from temperate to polar regions.

Habitat

Cobble or sandy beaches, rocky reefs, tidal mudflats and sandbars along the coast or in bays or estuaries.  Five subspecies are recognized: the Eastern Atlantic harbor seal occurs in the eastern Atlantic from Brittany to the Barents Sea in northwestern Russia and north to Svalbard, with occasional sightings as far south as northern Portugal. The Western Atlantic harbor seal occurs in the western Atlantic from the mid-Atlantic United States to the Canadian Arctic and east to Greenland and Iceland. The Ungava seal only lives in a few lakes and rivers in northern Quebec, Canada, that drain into Hudson and James Bays. The Eastern Pacific harbor seal is found in the eastern Pacific from central Baja California, Mexico to the end of the Alaskan Peninsula and possibly to the eastern Aleutian Islands. The Kuril seal ranges from either the end of the Alaskan Peninsula or the eastern Aleutians to the Commander Islands, Kamchatka, and through the Kuril Islands to Hokkaido.

Population

Global:  Harbor seals are distribute very widely and their total population size is estimated at about 600,000
Local:   The most abundant subspecies is P.v. richardsi. An estimated 170,000 individuals inhabit the eastern North Pacific from the Pribilof Islands to Baja California, Mexico

Status

IUCN:  Least concern; however, the subspecies Phoca vitulina mellonae, the Ungava seal, is listed separately as Endangered
CITES:   Not listed
USFWS:  Not listed

Fun Facts

1. Harbor seals belong to the scientific order Pinnipedia, which includes seals, sea lions, and walruses. Seals differ from sea lions in a number of ways, including having shorter, stouter flippers, and no visible earflaps.
2. Unlike most other pinnipeds, harbor seals are generally solitary and rarely interact with one another. An exception to this is the strong mother-pup bond maintained until the pup is weaned. When hauled out, adults maintain a meter or more (3 or more ft) between them. Harbor seals are not highly communicative, but if threatened a seal may respond by snorting, growling, lunging, scratching, or other aggressive gestures.
3. Harbor seals swim with alternate back-and-forth movements of their hind flippers. Harbor seals can remain submerged for up to 28 minutes and dive to depths of 90 m (295 ft); however, they routinely forage in shallower waters.
4. Harbor seals along the Pacific coast usually give birth between February and July. The well-developed pup may measure up to 100 cm (39 in.) and 12 kg (26 lbs.). A pup nurses for 4 to 6 weeks. Its mother's milk, containing as much as 45% milk fat, enables the pup to more than double its weight by the end of the weaning process.
5. Known predators include killer whales, great white and Greenland sharks, and possibly other shark species, Steller sea lions, walrus, eagles, gulls, and ravens.
6. For more information about harbor seals, explore the Harbor Seal InfoBook.

Ecology and Conservation

All commercial harvesting ceased several decades ago. Harbor Seals were protected in Canada in 1970 by the Fisheries Act.

The U.S. Marine Mammal Protection Act of 1972 provided a broad prohibition on taking of any marine mammal. However, Alaska Natives are allowed to harvest harbor seals for subsistence and creation of authentic handicrafts, and Native handicrafts and edible portions may be sold in Native villages and towns. Some subsistence harvesting still occurs in Alaska, as well as in Canada and Greenland. In Russia, Kuril seals are listed in the Red Data Book and there is no legal harvest.

Bibliography

Byrum, J. Pinnipeds From Pole to Pole: Seals, Sea Lions and Walruses. SeaWorld Education Department Publication. San Diego. SeaWorld, Inc. 2000.

Jefferson, T.J. Leatherwood, S. and M.A. Webber. FAO Species Identification Guide. Marine Mammals of the World. Rome. FAO, 1993.

Reeves, R.R., Stewart, B.S. and S. Stephen. The Sierra Club Handbook of Seals and Sirenians. San Francisco: Sierra Club Books, 1992.

Nowak, Ronald M. (ed.). Walker's Mammals of the World. Vol. II. Baltimore: Johns Hopkins University Press, 1991.

Parker, S. (ed.). Grizmek's Encyclopedia of Mammals. Vol. IV. New York: McGraw-Hill Publishing Co., 1990.

Reeves, R. R., Stewart, B.S., Clapman, P.J., and J.A. Powell (Peter Folkens illustrator). National Audubon Society: Guide to Marine Mammals of the World. New York: Random House, 2002.

Riedman, M. The Pinnipeds: Seals, Sea Lions and Walruses. Berkeley and Los Angeles. University of California Press. 1990.

http://animaldiversity.ummz.umich.edu

Lowry, L. 2016. Phoca vitulina. The IUCN Red List of Threatened Species 2016: e.T17013A45229114. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T17013A45229114.en/. Downloaded on 27 September 2018.