Phoca vitulina 

Scope: Global

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Carnivora Phocidae

Scientific Name: Phoca vitulina
Species Authority: Linnaeus, 1758
Infra-specific Taxa Assessed:
Regional Assessments:
Common Name(s):
English Harbor Seal, Harbour Seal, Common Seal
French Phoque veau-marin
Spanish Foca Moteada
Taxonomic Notes: There are five commonly recognized subspecies of Harbor Seals: Phoca vitulina richardii, the Eastern Pacific Harbor Seal; P. v. stejnegeri, the Kuril Seal or Western Pacific Harbor Seal; P. v. vitulina, the Eastern Atlantic Harbor Seal; P. v. concolor the Western Atlantic Harbor Seal; and P. v. mellonae, the Ungava Seal or Seal Lake Seal (Rice 1998). Berta and Churchill (2011) recognized only one subspecies in the North Pacific (P. v. richardii) and one in the North Atlantic (P. v. vitulina). The IUCN Pinniped Specialist Group believes that pending additional genetics studies, conservation and management of these taxa are best served by following Rice (1998) and maintaining the five subspecies.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2016
Date Assessed: 2016-01-04
Assessor(s): Lowry, L.
Reviewer(s): Harvey, J.
Facilitator/Compiler(s): Ahonen, H., Pollock, C.M., Chiozza, F. & Battistoni, A.
Harbor Seals are distributed very widely and their total population size is estimated at about 600,000. Trend in abundance is unknown for four of the subspecies; the Eastern Pacific Harbor Seal is known to be increasing. While in many areas Harbor Seals share the coastal zone with increasing human populations and suffer some impacts as a result, current threats appear to be tolerable and/or manageable. As a species, the Harbor Seal does not meet any IUCN criteria for a threatened listing and is listed as Least Concern. However, the subspecies Phoca vitulina mellonae, the Ungava Seal, is listed separately as Endangered.
Previously published Red List assessments:

Geographic Range [top]

Range Description:Harbor Seals are one of the most widespread of the pinnipeds. They are found throughout coastal waters of the northern hemisphere, from temperate to polar regions. Five subspecies are recognized: the Eastern Atlantic Harbor Seal occurs in the eastern Atlantic from Brittany to the Barents Sea in northwestern Russia and north to Svalbard, with occasional sightings as far south as northern Portugal, the Western Atlantic Harbor Seal occurs in the western Atlantic from the mid-Atlantic United States to the Canadian Arctic and east to Greenland and Iceland, the Ungava Seal only lives in a few lakes and rivers in northern Quebec, Canada, that drain into Hudson and James Bays, the Eastern Pacific Harbor Seal is found in the eastern Pacific from central Baja California, Mexico to the end of the Alaskan Peninsula and possibly to the eastern Aleutian Islands, and the Kuril Seal ranges from either the end of the Alaskan Peninsula or the eastern Aleutians to the Commander Islands, Kamchatka, and through the Kuril Islands to Hokkaido (Rice 1998).
Countries occurrence:
Belgium; Canada (Labrador, New Brunswick, Newfoundland I, Nova Scotia, Nunavut, Prince Edward I., Québec); Denmark; Finland; France; Germany; Greenland; Iceland; Ireland; Japan; Mexico; Netherlands; Norway; Russian Federation; Svalbard and Jan Mayen; Sweden; United Kingdom; United States
Portugal; Spain
FAO Marine Fishing Areas:
Atlantic – northeast; Atlantic – northwest; Pacific – eastern central; Pacific – northeast; Pacific – northwest
Additional data:
Estimated area of occupancy (AOO) - km2:7145752Continuing decline in area of occupancy (AOO):No
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:59915539
Continuing decline in extent of occurrence (EOO):NoExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:No
Extreme fluctuations in the number of locations:No
Upper elevation limit (metres):3Lower depth limit (metres):480
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Available data on Harbor Seal abundance were compiled and reviewed in the 2016 Red List assessments for the five recognized subspecies.
Estimates of the number of mature individuals, and population trend, for each of those subspecies were as follows:
  • Eastern Atlantic Harbor Seal--65,000, trend unknown
  • Western Atlantic Harbor Seal--60,000, trend unknown
  • Eastern Pacific Harbor Seal--170,000, increasing
  • Kuril Seal--<10,000, trend unknown
  • Ungava Seal--50, trend unknown
Combining those estimates, the total number of mature Harbor Seals worldwide is about 315,000. Bjorge et al. (2010) estimated the total worldwide population of Harbor Seals as approximately 610,000-640,000. The overall trend in numbers is unknown.
Current Population Trend:Unknown
Additional data:
Number of mature individuals:315000Continuing decline of mature individuals:No
Extreme fluctuations:NoPopulation severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Harbor Seals live mostly in the coastal waters of the continental shelf and slope, and are commonly found in bays, rivers, estuaries, and intertidal areas. They also occur in some lakes (Burns 2009). They will haul out on rocks, sand and shingle beaches, sand bars, mud flats, vegetation, sea ice, glacial ice and a variety of man-made structures. They usually lie close to the water to permit a rapid escape from threats. Sex and age segregation is common in most populations (Kovacs et al. 1990). They are usually extremely wary and shy on land and therefore it is almost impossible to approach them when they are hauled out without stampeding them into the water. However, habituation to human activities in their vicinity can occur. Most haul-out sites are used daily, based on tidal cycles and other environmental variables, although foraging trips can last for several days (Grellier et al. 1996, Lowry et al. 2001). Although Harbor Seals are considered a non-migratory species with a high degree of site fidelity to a haul out, long-distance dispersal of juveniles, emigration, and establishment of new haul out sites do occur (Ries et al. 1999, Bjorge et al. 2002). There is also evidence of seasonal changes in at-sea distribution and home range size by age class and sex (Lowry et al. 2001, Dietz et al. 2013).

Adult male Harbor Seals are 1.6-1.9 m long and weigh 70-150 kg, adult females are 1.5-1.7 m and 60-110 kg. At birth, pups are 82-98 cm and 8-12 kg (Burns 2009). Males become sexually mature when four to six years old. Female Harbor Seals usually become sexually mature when three to five years old (Harkonen and Heide-Jorgensen 1990). Throughout the Harbor Seal's range, the time of birthing varies widely and may follow a latitudinal cline (Temte 1994). Peak pupping date varies from mid March to early September. The mating system is promiscuous, or weakly polygynous, with males defending underwater calling sites (Boness et al. 2006, Van Parijs and Kovacs 2002). Mating usually takes place in the water, with females coming into oestrus about a month after giving birth. Molt follows the pupping and mating season. The timing of onset of molt depends on the age and sex of the animal with yearlings molting first and adult males last (Reder et al. 2003).

Females give birth to a single precocial pup. Most pups shed their silvery gray lanugo coat in the uterus before birth and are born with a juvenile pelage. Exceptions to this include pups born prematurely, and some that are born early in the breeding season (Bowen et al. 1994). Pups usually enter the water soon after birth, and because of tidal inundation at many sites used for birthing, this often occurs within hours (Burns 2009). Pups are suckled for an average of 26 days (Drescher 1979). Unlike Grey Seals, Harbor Seal females need to feed during the lactation period to produce adequate milk for their rapidly growing pup, and as a result they undertake regular feeding trips to sea (Thompson et al. 1994, Bowen et al. 2001).

At sea, Harbor Seals are most often seen alone, but they occasionally occur in small groups. Localized aggregations can form in response to feeding opportunities and concentration of prey. Harbor Seals are generalist feeders that take a wide variety of fish, cephalopods, and crustaceans obtained from surface, mid-water, and benthic habitats (e.g., Pitcher 1980, Harkonen 1987, Olesiuk et al. 1990, Pierce et al. 1991). Their diet is highly varied, and animals from different populations and areas show differences, and there is also variation associated with seasonal and interannual changes in the abundance of prey (e.g., Tollit et al. 1997, Thompson et al. 1996). Generally, a few species dominate the diet at any one location and time of year. They are primarily a coastal species with dive depths generally less than 100 m (Tollit et al. 1998), but dives to as much as 480 m have been recorded in Alaska (Frost et al. 2001).

Longevity is about 30-35 years with females living longer than males. Known predators include Killer Whales, Great White and Greenland Sharks, and possibly other Shark species, Steller Sea Lions, Walrus, Eagles, Gulls, and Ravens (Burns 2009).
Systems:Terrestrial; Freshwater; Marine
Continuing decline in area, extent and/or quality of habitat:No
Generation Length (years):14.8
Movement patterns:Not a Migrant

Use and Trade [top]

Use and Trade: Harbor Seals were commercially harvested in British Columbia, and commercial and recreational use also occurred in Alaska. All commercial harvesting ceased several decades ago. Harbor Seals were protected in Canada in 1970 by the Fisheries Act. The U.S. Marine Mammal Protection Act of 1972 provided a broad prohibition on taking of any marine mammal. However, Alaska Natives are allowed to harvest Harbor Seals for subsistence and creation of authentic handicrafts, and Native handicrafts and edible portions may be sold in Native villages and towns. Some subsistence harvesting still occurs in Alaska, as well as in Canada and Greenland. In Russia, Kuril Seals are listed in the Red Data Book and there is no legal harvest.

Threats [top]

Major Threat(s): Historically, there have been organized population reduction programs and bounty schemes for Harbor Seals in some range states, largely because of perceived competition with fisheries. Hunting and/or licensed killing to protect fisheries has largely been eliminated but subsistence hunting by Alaska Natives is allowed in the US. In the eastern Atlantic, Harbor Seal population reduction programs date from the early 1980s and 1990s in Iceland and Scotland, respectively (Bowen and Lidgard 2012) and continue at some level today (e.g., Butler et al. 2008). An extermination program at the beginning of the 20th century dramatically depleted Harbor Seals in the Baltic Sea. Quotas for Harbor Seals are set annually in Norway and a bounty is paid to hunters in several regions of the country.

Mass die-offs from viral outbreaks have killed thousands of Harbor Seals on both sides of the Atlantic, but most notably in Europe caused by phocine distemper virus (Dietz et al. 1989, Harkonen et al. 2006, Reijnders 1986). Because Harbor Seals haul out on nearshore and coastal mainland sites, they are exposed to terrestrial wild carnivores, pets and feral animals, and waste from human populations that create an increased risk of exposure to communicable diseases.

Because many Harbor Seals live and feed in close proximity to large populations of humans they are exposed to, and can accumulate, high levels of industrial and agricultural pollutants (e.g., organochlorines, PCBs, dioxins) that negatively affect reproduction (Reijnders 1986), induce vitamin deficiency (Brouwer et al. 1989), and cause immunosuppression (Ross et al. 1995). Both chronic oil spills and discharges and episodic large-scale spills can cause direct mortality (Frost et al. 1994, 1999; Hoover-Miller et al. 2001) and could have long term impacts on Harbor Seal health and their environment.

Noise and other disturbance from offshore oil and gas, and the development of offshore renewable energy such as wind farms, may also affect the foraging behavior and physical condition of Harbor Seals (Hastie et al. 2015, Skeate et al. 2012).

Harbor Seals live in coastal areas many of which are heavily fished and this results in entanglement and bycatch issues (see Desportes et al. 2010) Overfishing and environmental variability (including global climate change) may also impact Harbor Seal prey populations.

Conservation Actions [top]

Conservation Actions: Harbor seals at Svalbard are protected under the Norwegian National Red List. Hunting of Harbor Seals in the Baltic Sea was prohibited in 1970 and management of this species in the Baltic Sea and Southern Scandinavian waters is the responsibility of HELCOM. Denmark and Sweden have established Harbor Seal sanctuaries. Neighboring states of the Wadden Sea have signed a trilateral agreement for the management of Harbor Seals. Since 1994, Harbor Seals have been considered vulnerable on the French national Red List. In the United Kingdom, Harbor Seals are protected under the Conservation of Seals Act and the Marine Scotland Act.

In the United States the Harbor Seal is protected from all but Alaska Native subsistence hunting by the Marine Mammal Protection Act of 1972, which also prohibits importation of parts or products from all seals. In Canada, the management of Seals is regulated within the Canadian Department of Fisheries and Oceans though the Fisheries Act and the Marine Mammal Regulations of 1993. Ungava Seals are being considered for designation as “Endangered” by COSEWIC and are listed as “Schedule 3, Special Concern” under Canada’s Species at Risk Act. In Greenland, adult Harbor Seals are protected but not subadults or pups. In Russia, Kuril Seals are listed in the Red Data Book.

Citation: Lowry, L. 2016. Phoca vitulina. The IUCN Red List of Threatened Species 2016: e.T17013A45229114. . Downloaded on 21 October 2016.
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