North Coast Marine Mammal Center

Marine Mammals

Click on the links below to find out more about each marine mammal

Harbor Seal

Phoca vitulina ~ Meaning of Latin name: calf-like seal

Harbor Seal Profile

Description

  • 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.
  • In San Francisco Bay, many harbor seals are fully or partially reddish in color.
  • This may be caused by an accumulation of trace elements such as iron or selenium in the ocean or a change in the hair follicle.

Range

  • 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.

Behavior

  • Harbor seals spend about half their time on land and half in water, and they sometimes sleep in the water.
  • They can dive to 1,500 feet (457 m) for up to 40 minutes, although their average dive lasts three to seven minutes and is typically shallow.
  • They are opportunistic feeders, eating sole, flounder, sculpin, hake, cod, herring, octopus, and squid.

Mating and Breeding

  • In California, harbor seal pups are born in March and April and weigh between 13-18 pounds at birth.
  • If born prematurely, harbor seals retain a whitish lanugo coat (which is usually lost before birth).
  • A pup can swim at birth, and will sometimes ride on its mother’s back when tired.
  • Pups make a bleating noise that sounds like “maaaa.” After about four weeks, the pups are weaned.
  • Adult females usually mate and give birth every year.
  • They may live 25 to 30 years.

Status

  • 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.

Steller Sea Lion

Eumetopias jubatus ~ Meaning of Latin name: having a broad forehead and mane
Steller Sea Lion

Photo by Ron LeValley

Description

  • Steller or northern sea lions are sometimes confused with California sea lions, but are much larger and lighter in color.
  • Males may grow to 11 feet (3.25 m) in length and weigh almost 2,500 pounds (1120 kg).
  • Females are much smaller, and may grow to nine feet (2.9 m) in length and weigh 1,000 pounds (350 kg).
  • Steller sea lions are light tan to reddish brown in color. They have a blunt face and a boxy, bear-like head.
  • Adult males do not have a visible sagittal crest (the bump on the top of their heads) as is seen in adult male California sea lions.
  • Stellers have a bulky build and a very thick neck, which resembles a lion’s mane, hence the name “sea lion.”

Range/Habitat

  • Stellers are found throughout the North Pacific Rim from Japan to central California.
  • Unlike California sea lions, Stellers tend to remain off shore or haul out in unpopulated areas.
  • Breeding occurs along the North Pacific Rim from Ano Nuevo Island in central California to the Kuril Islands North of Japan, with the greatest concentration of rookeries (breeding grounds) in the Gulf of Alaska and Aleutian Islands.

Behavior

  • Steller sea lions eat a variety of fishes, invertebrates, and occasionally other pinnipeds.
  • Known predators are killer whales (orcas) and white sharks.

Mating and Breeding

  • Pups are born on offshore islands from mid-May to mid-July, and weigh 35-50 pounds (16-23 kg).
  • Mothers stay with pups for one to two weeks before hunting at sea. Then they spend roughly equal amounts of time hunting and nursing pups on land.
  • Pups usually nurse for a year, but some continue to nurse for up to three years.
  • Mating occurs 10-14 days after the pups are born.
  • Dominant mature males maintain territories for one to two months and mate with many females.
  • During the breeding season, males do not eat.

Status

  • The current population of Steller sea lions is about 40,000, with about 500 living in California. However, there is great concern about this population, which has dropped by 80% in the last 30 years.
  • In 1997, the western stock in Alaska was listed as endangered and the eastern stock of the Continental United States and Canada was listed as threatened.
  • Reasons for this decline are not known. However, researchers believe that a decline in the fish they eat is the biggest cause.
  • The decline of fish could be due to increasing commercial fisheries in the Gulf of Alaska.
  • Drowning, entanglement in nets, and gunshot are all possible reasons for the Stellers’ decline.
  • Stellers are protected under the Marine Mammal Protection Act, which forbids the killing, harming, or harassing of any marine mammal, as well as the Endangered Species Act.
  • With this federal protection, there is hope for the recovery of the Steller sea lion population.

Northern Elephant Seal

Mirounga angustirostris ~ Meaning of Latin name: having a narrower snout than the sou

Photo by Lyn Brett

Description

  • Elephant seals are well named because their large noses resemble an elephant’s trunk.
  • Males begin developing this enlarged nose, or proboscis, at sexual maturity (about three to five years), and it is fully developed by seven to nine years. Adult males may grow to over 13 feet (4 m) in length and weigh up to 4,500 pounds (2,000 kg).
  • The females are much smaller at 10 feet (3 m) in length and 1,500 pounds (600 kg).
  • The northern elephant seal is the second largest seal in the world, after the southern elephant seal.
  • The elephant seal is in the phocid, or true seal, family. It lacks external ear flaps and moves on land by flopping on its belly. The elephant seal has a broad, round face with very large eyes.
  • Pups are born with a black coat which is molted, or shed, at about the time of weaning, revealing a sleek, silver-gray coat. Within a year, the coat will turn silvery brown.

Range/Habitat

  • Northern elephant seals are found in the North Pacific, from Baja California, Mexico to the Gulf of Alaska and Aleutian Islands.
  • During the breeding season, they live on beaches on offshore islands and a few remote spots on the mainland.
  • The rest of the year, except for molting periods, the elephant seal lives well off shore (up to 5,000 miles, or 8,000 km), commonly descending to over 5,000 feet (1,524 m) below the ocean’s surface.

Behavior

  • While living in the open ocean, northern elephant seals spend a lot of time diving, up to two hours at a time. They rarely spend more than four minutes at the surface of the water between dives.
  • It is believed that they eat deep-water, bottom-dwelling marine animals such as ratfish, swell sharks, spiny dogfish, eels, rockfish, and squid.
  • Elephant seals molt each year between April and August, shedding not only their hair but also the upper layer of their skin as well. This is known as catastrophic molt.

Mating and Breeding

  • Each winter, elephant seals arrive at their breeding beaches in Mexico and California. Males are the first to arrive and they fight each other to establish dominance. During this time, dominant males will often inflate their noses and produce a noise that sounds like a drum to warn lesser males away. Females soon arrive, and associate with dominant males. Several days after coming onto the beaches the females give birth to the pups they have been carrying since last year. Pups weigh 75 pounds (35 kg) or more and are about four feet (1.25 m) in length. The pups nurse for about 28 days, generally gaining about 10 lbs (4.5 kg) a day.
  • Around the time of weaning, the mother will mate with one or more of the dominant males.
  • After the nursing period, the mother returns to sea. For the next two months, weaned pups, called weaners, remain on rookery beaches, venturing into the water for short periods of time, perfecting their swimming and feeding abilities.
  • Eventually, the pups will learn to feed on squid, fish, and occasionally small sharks.

Status

  • The northern elephant seal is a conservation success story.
  • They were hunted to the brink of extinction, primarily for their blubber, which was used for lamp oil.
  • By 1910, it is estimated that there were less than 100 elephant seals, all found on Guadalupe Island off Baja California, MX.
  • Today, the northern elephant seal population is over 150,000 and is probably near the size it was before they were over-hunted.

California Sea Lion

Zalophus californianus ~ Meaning of Latin name: with crest and of California
California Sea Lion

Photo by Thomas Mangelsen

Description

  • California sea lions are known for their intelligence, playfulness, and noisy barking.
  • Their color ranges from chocolate brown in males to a lighter, golden brown in females.
  • Males may reach 1,000 lbs. (more often 850 lbs., or 390 kg) and seven feet (2.1 m) in length.
  • Females grow to 220 lbs. (110 kg) and up to six feet (1.8 m) in length.
  • They have a “dog-like” face, and at around five years of age, males develop a bony bump on top of their skull called a sagittal crest. The top of a male’s head often gets lighter with age.
  • These members of the otariid or walking seal family have external ear flaps and large flippers that they use to “walk” on land.
  • The trained “seals” in zoos and aquariums are usually California sea lions.

Range/Habitat

  • California sea lions are found from Vancouver Island, British Columbia to the southern tip of Baja California in Mexico.
  • They breed mainly on offshore islands, ranging from southern California’s Channel Islands south to Mexico, although a few pups have been born on Ano Nuevo and the Farallon Islands in central California.
  • There is a distinct population of California sea lions at the Galapagos Islands.
  • A third of the population in the Sea of Japan became extinct, probably during World War II.

Behavior

  • California sea lions are very social animals, and groups often rest closely packed together at favored haul-out sites on land, or float together on the ocean’s surface in “rafts.”
  • They are sometimes seen porpoising, or jumping out of the water, presumably to speed up their swimming.
  • Sea lions have also been seen “surfing” breaking waves.
  • California sea lions are opportunistic eaters, feeding on squid, octopus, herring, rockfish, mackerel, and small sharks.
  • In turn, sea lions are preyed upon by Orcas (killer whales) and great white sharks.

Mating and Breeding

  • Most pups are born in June or July and weigh 13-20 lbs. (6-9 kg).
  • They nurse for at least five to six months and sometimes over a year.
  • Mothers recognize pups on crowded rookeries through smell, sight, and vocalizations. Pups also learn to recognize the vocalizations of their mothers.
  • Breeding takes place a few weeks after birth.
  • Males patrol territories and bark almost continuously during the breeding season.

Status

  • Their population is growing steadily, and California sea lions can be seen in many coastal spots such as Seal Rock or PIER 39 in San Francisco.
  • The current population is approximately 200,000.

Guadalupe Fur Seal

Arctocephalus townsendi

Photo by Ron LeValley

Description

  • Related to the northern fur seal (but slightly smaller), this animal can grow to 5-6 ft in length with females being smaller than males.
  • Adult males can weigh 300 lbs and females can weigh 100 lbs.
  • A member of the otariid family, these animals are not true seals but rather sea lions with exterior ear flaps and an ability to walk on land with “all fours”
  • The Guadalupe fur seal is dark brown to blackish gray and has a yellowish gray head and neck. It has a silvery appearing mane formed by long guard hairs surrounding its neck.
  • These animals have long pointed muzzles (unlike the northern fur seal) that are said to resemble a collie’s snout
  • The most common noises Guadalupe fur seals make are a deep growl or even a roar sound unlike the humorous barking of a California sea lion.

Range/Habitat

  • Hunted nearly to extinction prior to the 20th century these animals are still in a precarious situation. Two fishermen in 1926 reported counting at least 40 or so of these sea lions off of Guadalupe Island Mexico and eventually brought two back to the San Diego Zoo in 1928.
  • Prior to intensive hunting by humans, these sea lions inhabited areas from the Farallan islands off San Francisco to San Benito islands off Baja California, Mexico.
  • Now it is believed the majority of the population is isolated to Guadalupe island; however stranding reports of these sea lions have been noted along the Central California coast.

Behavior

  • Little is known about the behavior of Guadalupe fur seals but it is said they are pelagic spending the majority of their lives out at sea
  • Diet is mostly unknown but they do seem to eat squid and lanternfish

Mating and Breeding

  • It is predicted that the mating behavior of Guadalupe fur seals is quite similar to that of Northern fur seals and other sea lions.
  • Males will hold territories (typically less than 40 sq. ft. for Northern fur seals) and mate with multiple females.
  • Pups are born mid June to mid July
  • It is said that Guadalupe fur seals tend to breed in caves rather than open beaches possibly for better protection and have been noted to return to the same rookeries (places to give birth) time and time again

Status

  • Guadalupe fur seals were thought to be extinct before the start of the 20th century, however two live sea lions were brought to the San Diego Zoo in 1928. Populations off Guadalupe have been closely watched and are steadily increasing.
  • Total current populations are estimated to be above 7000
  • Currently Guadalupe fur seals are protected by law in the United States and Mexico.

Northern Fur Seal

Callorhinus ursinus

Northern Fur Seal

Description

  • Its name means bear-like, and the Europeans use to refer to them as sea bears.
  • Named for their thick fur, over 300,000 hairs per square inch, seal pelts use to be valued at 100 dollars each in 1977 (about 349.95 in 2009 dollars.)
  • Original populations of these seals probably exceeded 2 million, however years of heavy hunting threatened this species, but an international treaty in 1911 to stop pelagic (at sea) hunting of this species allowed numbers to climb.
  • The Northern fur seal is actually not a seal at all and belongs to the otariid family. Capable of walking on land and having exterior ear flaps, this “seal” is more like a sea lion.
  • Pups are born with a black coat that gradually becomes lighter around the belly and neck area.
  • Adults may have silver hairs around the back of the neck
  • Males are larger than females and are born at 12 lbs, eventually growing up to be 385-605 lbs and 7 feet in length
  • Females are generally about 10 lbs when born and grow to be 66-110 lbs and 4.5 ft in length
  • The Northern Fur seal looks different from the Guadalupe fur seal in coloration and muzzle shape. (Northern Fur Seal’s muzzle are more stout)

Range

  • The northern Fur seal’s habitat ranges from Japan to the channel islands in California. Many of the breeding colonies are in the Pribilof Islands and Commander Islands in the Bering sea.
  • Smaller rookeries (birth places) exist on islands off Northern Japan, Robben Island, and San Miguel Island off of California
  • Frallon Island has just recently become an established rookery for the Northern Fur Seal.

Behavior

  • The Northern Fur Seal is called pelagic (at sea) because it spends the majority of its life at sea.
  • They mostly feed on schooling fish and other small prey like pollock, herring, hake, anchovy, and squid.
  • Generally they do not dive deeper than 200 ft (unlike the northern elephant seal) and they have a maximum recorded dive depth of 600 ft.
  • They may

Mating and Breeding

  • The northern fur seals have rookeries (breeding grounds) to which they return year after year. Typically they return to the one they were born at
  • Males will defend a territory usually about 40 square feet and breed with his harem (group of females)
  • The average harem size for a male is 40 females
  • Females give birth in early June and will nurse their young for about 10 days, then they will leave their pups to forage in the ocean and return in four to five days only to nurse again for two days. This cycle repeats until the pups reach their weaning age of about four months (sometimes longer)
  • Fur seals can live 26 years!

Status

  • Once severely hunted for their pelts (fur) the northern fur seal is making a great comeback. Under the protection of the Marine Mammal Act of 1972 these creatures can no longer be legally hunted unless for research or native substinance.
  • World populations are thought to be around 660,000 but declining slightly
  • Commercial fishing operations may be partly responsible for some decline in Northern fur seal populations through the use of commerical trolling nets in which seals can become entangled and of course overall declines in available fish stocks.

Sources

  1. http://www.marinemammalcenter.org/education/marine-mammal-information/pinnipeds/northern-fur-seal/
  2. Daugherty A.E.. Marine Mammals of California 1985.
  3. http://www.westegg.com/inflation/infl.cgi (inflation calculatior)

Harbor Porpoise

Phocoena phocoena

Photo by Ron LeValley

Description

  • The harbor porpoise is a small and chunky, beakless toothed whale that can reach lengths of 6 ft and weigh 160 lbs.
  • The females tend to weigh slightly more than the males
  • Harbor porpoises are one of the smallest marine mammals
  • They are dark gray and are dark blackish along their backs which fades to a light gray or white on their underside
  • The name porpoise is derived from the Latin porcus piscis or “pig fish” and are sometimes referred to as herring hogs because of their notorious habit of robbing herring from fishing nets.

Range

  • The Pacific Harbor Porpoise ranges from Pt. Barrow, Alaska, to central California in bays and harbors along the Pacific coast. The map to the right shows the range for both the Atlantic and Pacific Harbor Porpoises
    Porpoise Range

Behavior

  • Young porpoises must consume 7-8% of their body weight a day to survive.
  • Harbor porpoises eat a variety of fishes like herring, capelin, and sprat and also squid and the occasional clam or crustacean.
  • They tend to frequent bays and inshore waters and may occassionally travel up rivers.
  • Harbor porpoises rarely follow boats (like the common dolphin or false killer whale have been seen doing)
  • They have been spotted as far off as 20 miles from the shore.
  • They commonly come to the surface to breath every 25 seconds but can hold their breath for longer.
  • The deepest dive by a harbor porpoise recorded was 735 ft.

Mating and Breeding

  • Harbor porpoises are generally 3-4 years old before they breed.
  • Mating season is June to September and the female is pregnant for 11 months
  • Calves are typically 27-35 inches and weigh 14-22 lbs.

Status

  • Harbor porpoises are currently not endangered and world populations are relatively abundent however they are on the decline.
  • Entanglement in commercial fishing nets and competition with other marine mammals and humans for food have been cited as rising issues.
  • Other risks to the population include pesticides and habitat destruction.

Report a Distressed marine Mammal 707-465-6265

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