California sea lion (Zalophus californianus californianus):

            The California sea lion is the most common pinniped in California and its distribution extends from southern Mexico to southwestern Canada.  In California, they haul out along most of the coastline, but pup on the offshore islands from May to July.  Breeding takes place after the pupping season.  Pups are weaned within 4-8 months.  Males appear dark brown with a large sagittal crest and weigh up to 390 kg (860 lb) and reach lengths up to 2.4 m (7 ft. 10 in.).  Females are smaller with a tan coat, weigh up to 110 kg (240 lb), and reach lengths of 2.0 m (6 ft. 7 in.).  California sea lions prey on a variety of fish and cephalopods, mainly northern anchovy, Pacific sardine, Pacific whiting, Pacific mackerel, jack mackerel, shortbelly rockfish, and squid (Lowry et al. 1990, 1991; Lowry and Carretta 1999).  The United States California sea lion stock (from the U.S./Mexico border to Canada) is considered stable/increasing (Carretta et al. 2007), but fluctuates during El Niño events, disease outbreaks, domoic acid events, etc.

Pacific harbor seal (Phoca vitulina richardsi):

            Pacific harbor seals are widely distributed along the California coast and breed along the mainland and offshore islands.  Harbor seals have been sighted year-round and haul out for a variety of reasons, including: breeding, molting, resting, and thermoregulating.  Pupping is clinal and typically takes place from January – June; occurring earlier in their southern range and later in their northern range.  After pupping, the molting and mating period begins.  Pups, which are able to swim immediately after birth, are weaned within 3-6 weeks (average 4 weeks).  Pacific harbor seal pelage patterns range from tan with dark spots (in the northern range) to dark with light rings (in the southern range).  Unlike some other pinnipeds, harbor seals do not exhibit sexual dimorphism.  Males weigh up to 170 kg (370 lb) and reach lengths up to 1.9 m (6 ft. 3 in.); females weigh up to 130 kg (290 lb) and reach up to 1.7 m (5 ft. 7 in.) in length.  Harbor seals primarily feed on fish (e.g., herring, cod, flounder), cephalopods (e.g., octopus), and invertebrates (e.g., shrimp and amphipods) (Sergeant 1951; Spalding 1964; Bigg 1973; Rae 1973; Pitcher and Calkins 1979; Bigg 1981).  The California harbor seal stock appears to be stabilizing and may possibly be reaching its carrying capacity (Carretta et al. 2007).

Steller sea lion (Eumetopias jubatus):

            Steller sea lions (northern sea lions) are listed as “threatened” under the Endangered Species Act and “depleted” under the Marine Mammal Protection Act (Angliss and Outlaw 2007).  In California, Steller sea lions haul out and breed (late May - late June) mainly on the following northern offshore islands: Año Nuevo Island, Farallon Islands, Sugarloaf Island, and Southwest Seal Rock.  The largest population of Steller sea lions in California may be observed at Southwest Seal Rock in Crescent City.  The sites mentioned above are the main rookeries, however, other areas along the northern and central California coast are used as haul-out sites.  Pups are born with dark pelage and are weaned by one year of age.  Steller sea lions are similar to California sea lions in appearance, but are a lighter shade of brown and larger.  Males reach up to 3.3 m (11 ft.) in length and weigh up to 1100 kg (2400 lb).  Females are much smaller and reach up to 2.9 m (9 ft. 6 in.) in length and 350 kg (770 lb) in weight.  Steller sea lions feed on fish, cephalopods, crustaceans and mollusks (e.g., rockfish, sculpin, squid, octopus, shrimp, and crab) (Mathisen et al. 1962; Fiscus and Baines 1966).  The Steller sea lion population is divided into two Distinct Population Segments (DPS): a western U.S. stock and an eastern U.S. Stock. The western stock includes animals at and west of Cape Suckling, Alaska and the eastern stock range is east of Cape Suckling, Alaska (144° W) (Loughlin 1997).  The Steller sea lion population in California is from the eastern DPS stock and has continued to decline from historic numbers (Angliss and Outlaw 2007).

Northern elephant seal (Mirounga angustirostris):

            Northern elephant seals are the second most abundant pinniped species in California.  They haul out and breed along central and northern California and the Channel Islands.  Pupping and mating takes place during late December to March.  Adults then haul out from March to August to molt, with females arriving before males (Carretta et al. 2007).  Pups, which are born before the mating season begins, are weaned at 3-6 weeks.  Just after molting, elephant seal coats appear dark/silver, but their coat fades to tan by the next molting season.  Sexual dimorphism in elephant seals is very apparent: males are significantly larger than females and have a fleshy, enlarged rostrum.  Males reach up to 4.1 m (13 ft. 6 in.) in length and 2000 kg (4400 lb) in weight.  Females reach up to 3.0 m (10 ft.) long and weigh up to 600 kg (1300 lb).  Northern elephant seals generally prey on fish (e.g., Pacific whiting), cephalopods, (e.g., squid and octopus) and occasionally tunicates (Condit and Le Boeuf 1984; Hacker 1986; Antonelis et al. 1987).  The northern elephant seal California breeding stock population, including the Channel Islands and central California, is increasing (Carretta et al. 2007). 

Northern fur seal (Callorhinus ursinus):            

            In California, the only northern fur seal rookery is on San Miguel Island of the Channel Islands.  This population originated in the Pribolof Islands and has continued to increase with fluctuations during El Niño events since the 1960’s.  This species pups from May to June, breeds shortly after pupping, and may be found on San Miguel Island through November.  Pups are weaned at approximately 4 months of age and are born with black pelage.  Adult males are also dark (reddish brown – black), have a large mane, and reach up to 2.1 m (6 ft. 11 in.) in length and 270 kg (600 lb) in weight.  Females, however, are dark brown – gray and lighter on their lower chest, reach up to 1.5 m (4 ft. 11 in.) in length and weigh up to 60 kg (130 lb).  Northern fur seals primarily prey upon fish (e.g., Pollock, herring, lantern fish, and cod) and squid (Tayler et al. 1955; Niggol et al. 1959; Lander and Kajimura 1976; Gentry 1981; Kajimura 1984).  Unlike the Eastern Pacific stock (which is found in Alaska), the San Miguel Island northern fur seal stock is not listed as “depleted” under the Marine Mammal Protection Act (Carretta et al. 2007).

Guadalupe fur seal (Arctocephalus townsendi):

            Guadalupe fur seals, which mainly breed in Mexico at Isla Guadalupe and Isla Benito del Este, are not known to have specific haul-out sites or rookeries in California.  The Guadalupe fur seal is listed as “threatened” under the Endangered Species Act, and “depleted” and “strategic” under the Marine Mammal Protection Act (Carretta et al. 2007).  Although there are no known haul-out sites or rookeries in California, they have stranded as far north as Blind Beach (north of San Francisco) (Hanni et al. 1997) and some sightings have occurred on San Nicolas Island (Stewart and Yochem 1984) and San Miguel Island (Melin and DeLong 1999).  Historical numbers are unknown, but the Guadalupe fur seal range once included areas as far north as Monterey, CA before commercial sealing depleted the population.  Pupping occurs from early June through July and breeding takes place shortly after a female gives birth.  Pups are weaned at approximately nine months of age.  Both male and female pelage ranges from uniform dark brown to black, but males are significantly larger than females and have a thick mane.  Males reach up to 2.2 m (7 ft. 3 in.) in length, 220 kg (490 lb) in weight.  Females reach up to 1.9 m (6 ft. 3 in.) in length and weigh up to 55 kg (121 lbs).  Prey studies on Guadalupe fur seals are scarce, but prey remains in stomach content of stranded animals included squid (e.g., opalescent inshore squid, armhook squid, boreal clubhook squid) and fish (e.g., lantern fish, ridgeheads, sanddabs) (Hanni et al. 1997).