The harbor (or harbour) seal (Phoca vitulina), also known as the common seal, is a true seal found along temperate and Arctic marine coastlines of the Northern Hemisphere. The most widely distributed species of pinniped (walruses, eared seals, and true seals), they are found in coastal waters of the northern Atlantic and Pacific Oceans and the Baltic and North Seas.
Harbor seals are brown, silvery white, tan, or gray, with distinctive V-shaped nostrils. An adult can attain a length of 1.85 m (6.1 ft) and a mass of 132 kg (290 lb). Blubber under the seal's skin helps to maintain body temperature. Females outlive males (30–35 years versus 20–25 years). Harbor seals stick to familiar resting spots or haulout sites, generally rocky areas (although ice, sand, and mud may also be used) where they are protected from adverse weather conditions and predation, near a foraging area. Males may fight over mates under water and on land. Females bear a single pup after a nine-month gestation, which they care for alone. Pups can weigh up to 16 kg (35 lb) and are able to swim and dive within hours of birth. They develop quickly on their mothers' fat-rich milk, and are weaned after four to six weeks.
The global population of harbor seals is 350,000–500,000, but subspecies in certain habitats are threatened. Once a common practice, sealing is now illegal in many nations within the animal's range.
|Harbor (common) seal|
|in Argyll, Scotland|
|Range of Phoca vitulina|
Individual harbor seals possess a unique pattern of spots, either dark on a light background or light on a dark. They vary in color from brownish black to tan or grey; underparts are generally lighter. The body and flippers are short, heads are rounded. Nostrils appear distinctively V-shaped. As with other true seals, there is no pinna (ear flap). An ear canal may be visible behind the eye. Including the head and flippers, they may reach an adult length of 1.85 meters (6.1 ft) and a weight of 55 to 168 kg (120 to 370 lb). Females are generally smaller than males.
There are an estimated 350,000–500,000 harbor seals worldwide. While the population is not threatened as a whole, the Greenland, Hokkaidō and Baltic Sea populations are exceptions. Local populations have been reduced or eliminated through disease (especially the phocine distemper virus) and conflict with humans, both unintentionally and intentionally. Killing seals perceived to threaten fisheries is legal in the United Kingdom, Norway, and Canada, but commercial hunting is illegal. Seals are also taken in subsistence hunting and accidentally as bycatch (mainly in bottomset nets). Along the Norwegian coast, bycatch accounted for 48% of pup mortality.
Seals in the United Kingdom are protected by the 1970 Conservation of Seals Act, which prohibits most forms of killing. In the United States, the Marine Mammal Protection Act of 1972 prohibits the killing of any marine mammals and most local ordinances, as well as NOAA, instruct citizens to leave them alone unless serious danger to the seal exists.
The five subspecies of Phoca vitulina are:
Harbor seals prefer to frequent familiar resting sites. They may spend several days at sea and travel up to 50 km in search of feeding grounds, and will also swim 100+ miles upstream into fresh water in large rivers. Resting sites may be both rugged, rocky coasts, such as those of the Hebrides or the shorelines of New England, or sandy beaches. Harbor seals frequently congregate in harbors, bays, sandy intertidal zones, and estuaries in pursuit of prey fish such as salmon, menhaden, anchovy, sea bass, herring, mackerel, cod, whiting and flatfish, and occasionally shrimp, crabs, mollusks, and squid. Atlantic subspecies of either Europe or North America also exploit deeper-dwelling fish of the genus Ammodytes as a food source and Pacific subspecies have been recorded occasionally consuming fish of the genus Oncorhynchus. Although primarily coastal, dives to over 500 m have been recorded. Harbor seals have been recorded to attack, kill and eat several kinds of duck.
Harbor seals are solitary, but are gregarious when hauled out and during the breeding season, though they do not form groups as large as some other seals. When not actively feeding, they haul to rest. They tend to be coastal, not venturing more than 20 km offshore. The mating system is not known, but thought to be polygamous. Females give birth once per year, with a gestation period around nine months. Females have a mean age at sexual maturity of 3.72 years and a mean age at first parturition of 4.64. Both courtship and mating occur under water. Pregnancy rate of females was 92% from age 3 to age 36, with lowered reproductive success after the age of 25 years.
Birthing of pups occurs annually on shore. The timing of the pupping season varies with location, occurring in February for populations in lower latitudes, and as late as July in the subarctic zone. The mothers are the sole providers of care, with lactation lasting 24 days. Researchers have found males gather under water, turn on their backs, put their heads together, and vocalize to attract females ready for breeding. The single pups are born well developed, capable of swimming and diving within hours. Suckling for three to four weeks, pups feed on the mother's rich, fatty milk and grow rapidly; born weighing up to 16 kilograms, the pups may double their weight by the time of weaning.
Harbor seals must spend a great deal of time on shore when moulting, which occurs shortly after breeding. This onshore time is important to the lifecycle, and can be disturbed when substantial human presence occurs. The timing of onset of moult depends on the age and sex of the animal, with yearlings moulting first and adult males last. A female mates again immediately following the weaning of her pup. Harbor seals are sometimes reluctant to haul out in the presence of humans, so shoreline development and access must be carefully studied in known locations of seal haul out.
In comparison to many pinniped species, and in contrast to otariid pinnipeds, harbor seals are generally regarded to be more vocally reticent. However, they do utilize non-harmonic vocalizations to maintain breeding territories and to attract mates during specified times of year, and also during mother and pup interactions.
The California population of subspecies P. v. richardsi amounted to about 25,000 individuals as of 1984. Pacific harbor seals or Californian harbor seals are found along the entire Pacific Coast shoreline of the state. They prefer to remain relatively close to shore in subtidal and intertidal zones, and have not been seen beyond the Channel Islands as a pelagic form; moreover, they often venture into bays and estuaries and even swim up coastal rivers. They feed in shallow littoral waters on herring, flounder, hake, anchovy, codfish, and sculpin.
Breeding occurs in California from March to May, with pupping between April and May, depending on local populations. As top-level feeders in the kelp forest, harbor seals enhance species diversity and productivity. They are preyed upon by killer whales (orcas) and white sharks.
Considerable scientific inquiry has been carried out by the Marine Mammal Center and other research organizations beginning in the 1980s regarding the incidence and transmission of diseases in harbor seals in the wild, including analysis of phocine herpesvirus. In the San Francisco Bay, some harbor seals are fully or partially reddish in color, possibly caused by an accumulation of trace elements such as iron or selenium in the ocean, or a change in the hair follicles.
Although some of the largest pupping areas harbor seals are found in California, they are found north along the Pacific Coast in Oregon, Washington, British Columbia and Alaska. Large populations move with the season south along the West Coast of Canada and may winter on the islands in Washington and Oregon.
Harbor seals are normally found along the Atlantic Coast and islands from Maine southward to Massachusetts. Occasionally, areas further south in Connecticut, Long Island, New Jersey, and even North Carolina have reported small populations or stranded seals have been found in and near islands or on beaches. Harbor seals move south from eastern Canadian waters to breed along the coast of Maine in May and June, and return northward in fall. Massachusetts is the southernmost point of known pupping areas along the Atlantic Coast.
Andre the Seal (May 16, 1961 – July 19, 1986) was a male harbor seal pup found off the island of Robinson's Rock in Penobscot Bay, Maine, United States.Carpinteria State Beach
Carpinteria State Beach is a protected beach in the state park system of California, in Santa Barbara County, Southern California.Castro Rocks
Castro Rocks are several rocks in Richmond, California protruding from the waters in San Francisco Bay between Castro Point and Red Rock Island.The rocks lie almost directly under the Richmond-San Rafael Bridge (I-580). The rocks are named after Don Víctor Castro a local rancho-era land owner.Castro Rocks are the home of many harbor seals, which lie on them to rest and sunbathe. The rocks are the largest harbor seal rookery in the northern San Francisco Bay and the second largest in the Bay Area itself. There are also sometimes sea lions on the rocks. The rock's Harbor Seals also frequent Mowry Slough, Brooks Island, Yerba Buena Island, and Mare Island.The seals at this location have high levels of toxic pollutants including the DDT, PCBs, PBDEs, PFOS, PFOA, and mercury.Earless seal
The earless seals, phocids or true seals are one of the three main groups of mammals within the seal lineage, Pinnipedia. All true seals are members of the family Phocidae . They are sometimes called crawling seals to distinguish them from the fur seals and sea lions of the family Otariidae. Seals live in the oceans of both hemispheres and, with the exception of the more tropical monk seals, are mostly confined to polar, subpolar, and temperate climates. The Baikal seal is the only species of exclusively freshwater seal.Hoover (seal)
Hoover (c. 1971 – July 25, 1985) was a harbor seal who was able to imitate basic human speech.Hydrodynamic reception
Hydrodynamic reception refers to the ability of some animals to sense water movements generated by biotic (conspecifics, predators, or prey) or abiotic sources. This form of mechanoreception is useful for orientation, hunting, predator avoidance, and schooling. Frequent encounters with conditions of low visibility can prevent vision from being a reliable information source for navigation and sensing objects or organisms in the environment. Sensing water movements is one resolution to this problem.This sense is common in aquatic animals, the most cited example being the lateral line system, the array of hydrodynamic receptors found in fish and aquatic amphibians. Arthropods (including crayfish and lobsters) and some mammals (including pinnipeds and manatees) can use sensory hairs to detect water movements. Systems that detect hydrodynamic stimuli are also used for sensing other stimuli. For example, sensory hairs are also used for the tactile sense, detecting objects and organisms up close rather than via water disturbances from afar. Relative to other sensory systems, our knowledge of hydrodynamic sensing is rather limited. This could be because humans do not have hydrodynamic receptors, which makes it difficult for us to understand the importance of such a system. Generating and measuring a complex hydrodynamic stimulus can also be difficult.List of U.S. state mammals
A state mammal is the official mammal of a U.S. state as designated by a state's legislature. Many states also have separately officially designated state animals, state birds, state fish, state butterflies, and state reptiles. States similarly have state flowers, state trees and state songs.Mont-Saint-Michel Bay
The Mont-Saint-Michel Bay (French: baie du Mont-Saint-Michel, Breton: Bae Menez-Mikael) is located between Brittany (to the south west) and the Normandy peninsula of Cotentin (to the south and east). The bay is part of the club of the world's most beautiful bays (fr) and is listed as a UNESCO world heritage site. Due to the significant tidal movements in this region (over 10 meters) a large part of the bay is uncovered at low tide. There are two granitic islands in the bay: Tombelaine and the Mont-Saint-Michel. Many birds and harbor seal live in this area.Phoca
Phoca is a genus of the earless seals, within the family Phocidae. It now contains just two species, the common seal (or harbour seal) and the spotted seal (or largha seal). Several species formerly listed under this genus have been split into the genera Pusa, Pagophilus, and Histriophoca. Until recently, Phoca largha has been considered a subspecies of Phoca vitulina but now is considered its own species. For this reason, the fossil history of the genus is unclear, and it has formerly been used as wastebasket taxon for a number of fossils of uncertain affinity.Pinniped
Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic marine mammals. They comprise the extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals). There are 33 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage (descended from one ancestral line). Pinnipeds belong to the order Carnivora and their closest living relatives are bears and musteloids (weasels, raccoons, skunks, and red pandas), having diverged about 50 million years ago.
Seals range in size from the 1 m (3 ft 3 in) and 45 kg (99 lb) Baikal seal to the 5 m (16 ft) and 3,200 kg (7,100 lb) southern elephant seal, which is also the largest member of the order Carnivora. Several species exhibit sexual dimorphism. They have streamlined bodies and four limbs that are modified into flippers. Though not as fast in the water as dolphins, seals are more flexible and agile. Otariids use their front limbs primarily to propel themselves through the water, while phocids and walruses use their hind limbs. Otariids and walruses have hind limbs that can be pulled under the body and used as legs on land. By comparison, terrestrial locomotion by phocids is more cumbersome. Otariids have visible external ears, while phocids and walruses lack these. Pinnipeds have well-developed senses—their eyesight and hearing are adapted for both air and water, and they have an advanced tactile system in their whiskers or vibrissae. Some species are well adapted for diving to great depths. They have a layer of fat, or blubber, under the skin to keep warm in the cold water, and, other than the walrus, all species are covered in fur.
Although pinnipeds are widespread, most species prefer the colder waters of the Northern and Southern Hemispheres. They spend most of their lives in the water, but come ashore to mate, give birth, molt or escape from predators, such as sharks and killer whales. They feed largely on fish and marine invertebrates; but a few, like the leopard seal, feed on large vertebrates, such as penguins and other seals. Walruses are specialized for feeding on bottom-dwelling mollusks. Male pinnipeds typically mate with more than one female (polygyny), although the degree of polygyny varies with the species. The males of land-breeding species tend to mate with a greater number of females than those of ice breeding species. Male pinniped strategies for reproductive success vary between defending females, defending territories that attract females and performing ritual displays or lek mating. Pups are typically born in the spring and summer months and females bear almost all the responsibility for raising them. Mothers of some species fast and nurse their young for a relatively short period of time while others take foraging trips at sea between nursing bouts. Walruses are known to nurse their young while at sea. Seals produce a number of vocalizations, notably the barks of California sea lions, the gong-like calls of walruses and the complex songs of Weddell seals.
The meat, blubber and fur coats of pinnipeds have traditionally been used by indigenous peoples of the Arctic. Seals have been depicted in various cultures worldwide. They are commonly kept in captivity and are even sometimes trained to perform tricks and tasks. Once relentlessly hunted by commercial industries for their products, seals and walruses are now protected by international law. The Japanese sea lion and the Caribbean monk seal have become extinct in the past century, while the Mediterranean monk seal and Hawaiian monk seal are ranked endangered by the International Union for Conservation of Nature. Besides hunting, pinnipeds also face threats from accidental trapping, marine pollution, and conflicts with local people.Popeye (seal)
Popeye is a female harbor seal that has become the official seal of Friday Harbor on San Juan Island.Promise Island
Promise Island (Inuktitut: Nannuyuma; meaning: "polar bear") is located near the western shore of Hudson Bay. It is barely a square kilometer in area and rises 300 ft (91 m) in elevation on its northern side. It is located about 9 km (5.6 mi) from the community of Chesterfield Inlet, Nunavut, Canada, and is part of a loose chain of small islands running along the coast, including the Wag Islands and Pitsiulartok (Fairway Island).
The island is home to a wide range of wildlife, including the Arctic fox (alopex lagopus innuitus), the harbor seal (phoca hispida), the polar bear, the brown lemming (lemmus t. trimucronatus), the barren-ground caribou (rangifer arcticus), and the red phalarope.Richardson Bay
Richardson Bay (originally Richardson's Bay) is a shallow, ecologically rich arm of San Francisco Bay, managed under a Joint Powers Agency of four northern California cities. The 911-acre (369 ha) Richardson Bay Sanctuary was acquired in the early 1960s by the National Audubon Society. The bay was named for William A. Richardson, early 19th century sea captain and builder in San Francisco.
Richardson Bay is one of the most pristine estuaries on the Pacific Coast in spite of its urbanized periphery, since it supports extensive eelgrass areas and sizable undisturbed intertidal habitats. It is a feeding and resting area for a panoply of estuarine and pelagic birds, while its associated marshes and littoral zones support a variety of animal and plant life. Richardson Bay has been designated as an Important Bird Area (IBA), based upon its large number of annual bird visitors and residents, its sightings of California clapper rail and its strategic location in the flyway. The bay's waters are subject to a "no discharge" rule to protect the elaborate and fragile ecosystems present, including a complex fishery, diverse mollusk populations and even marine mammals such as the harbor seal.
Owing to its lack of depth and complicated channel structure, Richardson Bay is limited in boating uses to kayaking and small sailing craft. There are extensive hiking and bicycling paths at the bay perimeter, especially in the shore areas of Mill Valley and the town of Tiburon.Roar (vocalization)
A roar is a type of animal vocalization consisting of both a low fundamental frequency (pitch) and low formant frequency. Many mammals have the ability to produce roars and other roar-like vocalizations. These include big cats, gorillas, elephants, some bovids, howler monkeys, bears, red deer, some pinnipeds and hammer-headed bats.
The ability to roar has an anatomical basis, often involving modifications to the larynx and hyoid bone and enlarged internal air spaces for low-frequency acoustic resonance. While roaring, animals may stretch out their necks and elevate their heads to increase the space for resonance. Though usually airborne, some roars are emitted underwater, as in the case of the male harbor seal.San Francisco Seals (baseball)
The San Francisco Seals were a minor league baseball team in San Francisco, California, that played in the Pacific Coast League from 1903 until 1957 before transferring to Phoenix, Arizona. They were named for the abundant California sea lion and harbor seal populations in the Bay Area. The 1909, 1922, 1925, and 1928 Seals were recognized as being among the 100 greatest minor league teams of all time.Spotted seal
The spotted seal (Phoca largha), also known as the larga seal or largha seal, is a member of the family Phocidae, and is considered a "true seal". It inhabits ice floes and waters of the north Pacific Ocean and adjacent seas. It is primarily found along the continental shelf of the Beaufort, Chukchi, Bering and Okhotsk Seas and south to the northern Yellow Sea and it migrates south as far as northern Huanghai and the western Sea of Japan. It is also found in Alaska from the southeastern Bristol Bay to Demarcation Point during the ice-free seasons of summer and autumn when spotted seals mate and have pups. Smaller numbers are found in the Beaufort Sea. It is sometimes mistaken for the harbor seal to which it is closely related and spotted seals and harbor seals often mingle together in areas where their habitats overlap.The reduction in arctic ice floes due to global warming led to concerns that the spotted seal was threatened with extinction. Studies were conducted on its population numbers, with the conclusion, as of October 15, 2009, that the spotted seal population in Alaskan waters is not currently to be listed as endangered by NOAA.Strawberry Lagoon
Strawberry Lagoon is an inlet within Richardson Bay, Marin County, California, United States. This location, particularly on Strawberry Spit, is a winter haul-out area for the Harbor seal. Pressures of urban development at Strawberry Point along with increases in small boat traffic have diminished the use of this lagoon for seal haul out, noted as early as 1990.The Marine Mammal Center
The Marine Mammal Center is a private, non-profit U.S. organization that was established in 1975 for the purpose of rescuing, rehabilitating, and releasing, marine mammals who are injured, ill, or abandoned. It was founded in Sausalito, California by Lloyd Smalley, Pat Arrigoni, and Paul Maxwell. Since 1975 they rescued over 20,000 marine mammals. It also serves as a center for environmental research and education regarding marine mammals, namely cetaceans (whales and dolphins) and pinnipeds (seals, fur seals, and sea lions). Marine mammal abandonment refers to maternal separation; pups that have been separated from their mother before weaning. At the center, they receive specialized veterinary care; diagnosed, treated, rehabilitated, and ideally, released back into the wild. Animals in need of assistance are usually identified by a member of the public who has contacted the center. These animals represent the following major species: California sea lion, northern elephant seal, Pacific harbor seal, northern fur seal, and the southern sea otter. On a few occasions, the Marine Mammal Center has taken in Guadeloupe fur seals, Steller sea lions, and bottlenose/Pacific white-sided dolphins. The only non-mammals that the center takes in are sea turtles.