Harbor Seal

In Harbor and Bay, Mammals, Mudflats, Open Beaches, Slough Life, Tidal Channels by Administrator

Quick Facts

Scientific Name: Phoca vitulina
Family: Pinnipedae

Found at Elkhorn Slough

Main channel, sandy beaches, mudflats

Did you know…

Harbor seals are “true seals” and must move on land by flopping along on their bellies.

Harbor seals are found north of the equator in both the Atlantic and Pacific Oceans. In the northeast Pacific, they range from Alaska to Baja California, Mexico. They favor near-shore coastal waters and are often seen at sandy beaches, mudflats, bays, and estuaries. They are found throughout the main channel of the Elkhorn Slough including the Moss Landing Harbor, the mud flats by the mouth of the Slough and of course, Seal Bend.

Harbor seals spend their entire lives along the same stretch of coastline. To guard against California’s cold water temperatures, seals maintain a thick layer of fat beneath their skin, giving them a thick sausage shape. They spend many hours during low tide hauled out on a favorite sandbar or rocky island soaking in the warm sunshine. Harbor seals are the most vulnerable when out of the water and will quickly swim off if you get too close.

Harbor seals have spotted coats in a variety of shades from silver-gray to black or dark brown. They reach five to six feet (1.7-1.9 m) in length and weigh up to 300 pounds (140 kg). Males are slightly larger than females. They are true or crawling seals, having no external ear flaps. True seals have small flippers and must move on land by flopping along on their bellies.

Harbor seals are probably the least vocal of all pinnipeds.  They hunt for fish, crabs, and shellfish during high tide. Adult harbor seals can stay submerged for up to 30 minutes, but dives usually last only about three minutes. A two-day-old harbor seal pup can stay submerged for up to two minutes.

The total harbor seal population in the eastern north Pacific is estimated to be 330,000, and in California the estimated population was 40,000 in 1997. They are usually found in small groups, but sometimes occur in numbers of up to 500.

Research:

TECHNICAL REPORT: Harbor seals: factors that control distribution and abundance in Pacific Coast estuaries and a case study of Elkhorn Slough, California.

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