Harbor Seal  Phoca vitulina

Harbor seals are the most common marine mammal in the Pacific Northwest. Curious harbor seals sometimes rest vertically in the water while watching beachgoers.

Range

Harbor seals live in coastal areas throughout the North Pacific and North Atlantic oceans. They spend equal time on land and water and can occasionally be found in inland waterways and lakes.  There is a good chance you can spot a harbor seal at all sites along The Whale Trail.

Biology

Harbor seals are considered “true seals”.  They wriggle on their bellies to move, do not have external ears, and use their rear flippers to propel themselves through the water, unlike sea lions which are not considered true seals. 

  • Harbor seal fur provides excellent camouflage but little insulation; they rely on a thick blubber layer for warmth and buoyancy. 
  • They rarely vocalize. 
  • Their front teeth that are pointed and sharp, well-adapted for catching, tearing and swallowing  prey as opposed to holding and chewing. 
  • Harbor seals eat 7-10% of their body weight daily, preying on several species of fish and squid including pollack, flounder, cod and herring.  They may dive to 1,000 feet for up to 23 minutes to hunt. 
  • Female harbor seals become sexually mature at 3-5 years and males at 5-6 years.  Gestation is 10 months with pups usually born between May and September.  A female normally has only one pup every year.  
  • Pups are capable of swimming at birth and nurse on milk that is up to 42% fat, which helps them quickly build up a blubber layer. Pups remain with the mother four to six weeks.

Social Structure and Behavior

Harbor seals sleep on land or just below the surface of the water.  When sleeping underwater they come up to breathe every 5-10 minutes without waking up.

  • The normal, relaxed position of their nostrils is closed tight.  They must voluntarily open their nostrils in order to breathe. 

Harbor seals leap from the water and slap their flippers loudly on the surface in a territorial display. It is common for harbor seals to congregate at desirable “haulouts” or resting places.

Current and Historical Threats

From 1947 to 1960 bounties were placed on harbor seals in Washington State due to the perceived damage they did to the salmon fishery.  After roughly 17,000 were killed, with no apparent improvement to commercial fisheries, the bounty was discontinued. Seals are now protected by state and federal law in the U.S. and British Columbia and their numbers have rebounded. 

Predators of adult harbor seals include transient killer whales, sharks, and Steller sea lions. Bald eagles, dogs, coyote and bear also hunt pups on the beach.  Seal pup mortality is high -- up to 50% in the first year. 

  • Pups can be left on the beach for extended periods of time while their mothers feed. People and their pets should stay at least 100 yards away.

Harbor seals (especially in an urban environment) accumulate high levels of toxins such as PCBs and PDBEs in their bodies.  They are also at risk from oil spills, fishing gear entanglement, and harassment.

Learn More!

 Books:
A Harbor Seal Pup Grows Up (Baby Animals) by Joan Hewett and Richard Hewett, 2001 True Story Of Corky, The Blind Seal (True Zoo Stories) by Georgeanne Irvine, 1987 The Pinnipeds: Seals, Sea Lions, and Walruses by Marianne Riedman, 1991

Links:
http://www.nmfs.noaa.gov/pr/species/mammals/pinnipeds/harborseal.htm http://www.ecy.wa.gov/programs/sea/pugetsound/species/seal.html http://www.sealsitters.org/ www.nwr.noaa.gov/Marine-Mammals/upload/sealpups.pdf  

Sources

http://www.marinemammalcenter.org/education/marine-mammal-information/pinnipeds/pacific-harbor-seal/ http://www.nmfs.noaa.gov/pr/species/mammals/pinnipeds/harborseal.htm

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Facts

Length

Adult ♂ : 6 ft feet (1.9 m)

Adult ♀ : 5 ft (1.7 m)

Birth Length :29 to 40 inches (0.7 -1m)

Weight

Adult ♂ : 300 pounds (140 kg)

Adult ♀ : 245 pounds (110 kg)

Birth Weight : 20 to 24 lbs (9-11 kg)

Life Expectancy

25 - 30 years

Photos

The Whale Trail is a nonprofit organization in partnership with
Partners NOAA Seattle Aquarium People for Puget Sound Washington Department of Fish and Wildlife The Whale Museum National Marine Sanctuaries