Pacific Harbor Seal, Phoca vitulina richardii

Pacific Harbor Seal, Phoca vitulina richardii. Photograph taken  in a coastal region of San Diego, California, July 2017.

Phylogeny:  The Pacific Harbor Seal, Phoca vitulina richardii  (Gray, 1864), is a member of the Phocidae family of True Seals. They are a subspecies of the Harbor Seal, Phoca vitulina (Linnaeus, 1758). The genus Phoca is one of fourteen genera in this family, and there are two species in this genus. The Pacific Harbor Seal is also known as the Eastern Pacific Harbor Seal and the North Pacific Harbor Seals and in Mexico as Foca de Puerto.

Morphology:  Pacific Harbor Seals have stout, but streamlined, bodies and robust heads. The snout is broad and they lack ear flaps. The front flippers have strong claws. The hind flippers are longer than the fore flippers and extend straight to the rear. They vary in color including silver, gray, tan, whitish, and blackish. Most are spotted with darker colored spots, though some darker individuals have lighter colored markings. Male Harbor Seals reach 1.9 m (6.25 feet) in length, and 170 kg (370 lbs) in weight. Females are smaller having a maximum length of  1.7 m (5.5 feet) and 130 kg (290 lbs) in weight.

Habitat and Distribution:  Pacific Harbor Seals are found in the near shore waters of the temperate Eastern Pacific. They live in in bays, estuaries, river mouths, and along exposed shorelines. In the water, Pacific Harbor Seals are generally solitary. When they haul out on sandy or rocky shorelines, they are often found in groups.  This is especially true when they are molting or giving birth. These groups provide protection from shoreline predators including coyotes and bears. Most Harbor Seal colonies are on off-shore islands, where shoreline predators are less common. They spend most of their time near the surface or in the top 100 m (328 feet) of water, however, they can dive to depths of 427 m (1,400 feet). They have a somewhat limited range in Mexican waters. They are found along the west coast of the Baja California Peninsula and the southern Gulf of California, as far north as La Paz, Baja California Sur. Isla Asunción and Cedros Island are generally considered the southern limit of the range of their colonies.

Diet:   Pacific Harbor Seals are predatory carnivores. They eat a wide variety of crustaceans, fish, octopus and squid.

Predators:  Sharks and Killer Whales are the primary predators of Pacific Harbor Seals. Young pups are also prey for bears, coyotes, and eagles.

Reproduction:    As mammals, Pacific Harbor Seals are gonochoric (male or female for life). They reproduce sexually, with internal fertilization. The gestation period ranges from 9 to 11 months. They give birth, on land, to one pup. The pup will nurse for four to six weeks. Female Pacific Harbor Seals reach sexual maturity at three or four years of age; males take four or five years.

Ecosystem Interaction: Pacific Harbor Seals are known to host a variety of internal parasites including cestodes, nematodes, acanthocephalans, and bacteria. There are no commensal or symbiotic relationships documented for this species.

Human Interaction: Pacific Harbor Seals were historically hunted for their blubber, meat, fur, and skin. More recently, in the mid 1900’s, they were killed to prevent competition with fisheries. They are now protected through most of their range. Entanglement in fishing gear is now the biggest threat throughout their range. Pacific Harbor Seal colonies have become an ecotourism resource, especially when located in easily accessed areas. Their populations have been increasing since the 1970’s. From a conservation perspective the Pacific Harbor Seal is currently considered to be of Least Concern with stable and widely distributed populations.

Synonyms:  None