Who is whoHarp Seal (Pagophilus groenlandicus)
Distribution and Habitat
Harp seals inhabit the North Atlantic and Arctic Oceans from northern Russia, to Newfoundland and the Gulf of St. Lawrence, Canada. They are separated into three populations based on where they breed; the White Sea, the `West Ice' and the Northwest Atlantic `Gulf' and `Front' (see map). Harp seals are closely associated with pack ice, undergoing spring migrations of up to 2,500 km on their way to summer feeding grounds, returning south ahead of the new ice in the fall. All three populations exhibit similar patterns of annual migration, although the timing of specific events such as pupping, varies slightly from place to place.
Natural History
Adult male harp seals grow to about 1.7 m and 130 kg; females are slightly smaller. Gregarious by nature, harp seals haul out in dense herds to give birth and moult. Females and males reach sexual maturity at approximately 4-6 years of age. A single pup weighing about 11 kg (22 lbs) is born each year from mid February to March. Mating occurs after the pups are weaned at about 12 days. After mating, adult males are joined on the moulting patches by immature and non-breeding seals, followed by adult females. Harp seals consume a wide range of prey species and their diet appears to vary with age, season, location and year. Harp seals can live up to 30 years.
Status
The Northwest Atlantic harp seal population is the largest and most studied. The 2000 population size is estimated to be 5.2 million animals. The population is now showing signs of reaching the limit of its food base and may be declining as a result of increased sealing since 1996. In 1994 pup production and population size for the West Ice were estimated at 59,000 and 286,000, respectively. A 1998 survey in the White Sea found that pup production was on the order of 300,000 - 400,000, higher than previously thought. These results are consistent with a total population size of about 1.5 to 2.0 million animals.
Threats to the Species
All three populations are hunted annually. Over-exploitation, particularly in the Northwest Atlantic, and an expanding and unregulated trade in seal products remain a threat. Other potential threats include: proposals to cull harp seal populations, ostensibly to benefit fisheries; reduced food availability due to human overfishing or climate change; incidental catches in fishing gear; and, possibly, environmental contaminants.
Hooded Seal (Cystophora cristata)
Distribution and Habitat
Hooded seals are found only in the central and western North Atlantic (see map) and their distribution generally follows the seasonal limits of pack ice. There are four major breeding areas: the Gulf of St. Lawrence, the "Front" east of Newfoundland, Davis Strait (between Greenland and northern Canada) and the West Ice near Jan Mayan. Hooded seals are occasionally seen outside their normal range and have been spotted along the east coast of the U.S. south to Puerto Rico, on the West coast of the U.S. (as far south as California) and along the coast of Portugal.
Natural History
Hooded seals are generally regarded as solitary in nature, except during moulting and mating. Animals from all four breeding areas appear to congregate near eastern Greenland to moult (see map). Hooded seals are sexually dimorphic with males being larger than females. Male hooded seals also have a black, crescent shaped, inflatable nasal sac that when flacid droops down over the muzzle. With one nostril closed, male hooded seals can also inflate their nasal septum through the opposite nostril, producing a large red balloon-like structure. Both are used in courtship and dominance displays. Females lack these secondary sexual characteristics. Females give birth to one pup yearly on pack ice, away from the edges of ice floes. Pups are weaned in just four days, the shortest time for any mammal. Hooded seals feed on a variety of fishes and invertebrates including Greenland halibut (Reinhardtius hippoglossoides), redfish (Sebastes marinus), polar cod (Arctogadus glacialis) and squid.
Status and Protection
Two stocks of hooded seals are recognized; one in the Northwest Atlantic and a second in the Greenland Sea. There are currently no reliable abundance estimates for either stock although previous estimates for each stock were on the order of 500,000 individuals. Currently there are insufficient data to assess the status of either stock.
Threats to the Species
Hooded seals are hunted throughout their range and, considering the unknown status of both stocks, exploitation and international trade may constitute a threat to the species. This may be especially true where hunting is not well regulated. In Canada, for example, the 1996 quota (8,000) was exceeded by a factor of three (a total of 25,754 hooded seals were killed).
Grey seal (Halichoerus grypus)
Distribution and Habitat
Grey seals can be separated into three distinct populations based on their distribution, size and breeding season: Northwest Atlantic (from northern Labrador to Nantucket, Massachusetts), Northeast Atlantic (from northern Norway to the middle of France, and from northern Norway to the White Sea), and Baltic (northeastern Gulf of Finland, off southeastern Sweden, the archipelago separating the Gulf of Bothnia from the Baltic proper and the Soviet Baltic). Most of the Northwest stock gives birth on ice in the Northumberland Strait, and on sandy Sable Island. The majority of Northeast pupping occurs around the British Isles especially off the northeast coast of Scotland. Smaller colonies also exist in France, the Netherlands, Germany, the Faroe Islands, Norway and Russia.
Natural History
Grey seal males are considerably larger than the females. Of the three populations, the Northwest Atlantic grey seals are the largest, with males measuring up to 2.3 m and weighing 300-350 kg, and females measuring up to 2.0 m and 150-200 kg. The Northeast Atlantic grey seals appear smaller; males average about 2m in length and weigh 170-310kg; females average 1.8 m and 103-180 kg. Male grey seals are characterized by the long, arched, horse-like, or "Roman", nose, heavy shoulders and thick, folded skin of the neck region. The female’s nose is similar but shorter and narrower. The coat of mature males is dark brown, grey or black with lighter blotches on the neck and flanks. The female is lighter in colour, with dark spots on a grey, tan or yellowish background. In the water, grey seals tend to be solitary or in small groups, but on land they are gregarious and can be found hauled out with harbour seals in areas where the two species coexist. Each population breeds at a different time and variation within the populations also exist. Pups weigh 11-20 kg at birth and are weaned at about 3 weeks of age. At this time, mating occurs between waiting males and receptive females. Grey seals feed on a wide variety of fish, crustaceans and cephalopods. The diet varies with location, season and prey availability. Fasting occurs during the breeding and moulting seasons.
Status
The Northwest Atlantic population is estimated at 85,000-110,000 animals. In1990, the Northeast population consisted of about 102,000 grey seals, 85,000 of them found off the coast of Britain. The Baltic grey seal is thought to number between 2,000 and 3,000 animals.
Threats to the Species
In the past, grey seals have been killed for their skins, meat and oil in the UK, Iceland, Canada and the Baltic. Bounties and cull programs have been initiated by different countries over the last century. Today, grey seals are rarely used as a resource but are considered a pest in certain areas; culling initiatives and directed takes by fishers continue to be initiated because of perceived competition for commercial fish species, gear damage and as hosts of codworm (Pseudoterranova decipiens). Grey seals in the Baltic and White Sea appear to be adversely affected by pollution and entanglement in fishing gear.
Bearded seal (Erignathus barbatus)
Distribution and Habitat
The bearded seal is circumpolar in its distribution in arctic and subarctic waters. There are two recognised subspecies of bearded seal. The E. barbatus barbatus subspecies is found in the western Laptev Sea, Barents Sea and north Atlantic Ocean as far south as the Gulf of St. Lawrence in the western Atlantic and Iceland / Norway in the eastern Atlantic. The E. barbatus nauticus subspecies inhabits the remainder of the Arctic Ocean, as well as the Bering and Okhotsk Seas, being found as far south as Hokkaido.
Natural History
Bearded seals are solitary and inhabit areas of relatively shallow water and moving ice. If ice is not available they will haul out on land and gravel beaches. Bearded seals have a large, body with a disproportionately small head and square fore flippers. Both males and females are about 2.1-2.5 cm in length, and weigh about 200-360 kg. The coat varies from silver, blue-grey to chocolate brown above, with white or cream coloured patches. Males reach sexual maturity between 6 and 7 years, females between 3 and 6. Pups are born on pack ice from mid-March to mid-May, and weigh about 33 kg at birth, and are about 1.3m long. They have a brown or greyish lanugo with white patches on the face, and are able to enter the water within hours. Nursing lasts for 18-24 days. The males "sing" underwater to attract females or to defend underwater territories. Diet varies with location and age of the animal, and includes crabs, shrimps, clams, whelks, polychaetes, squit, octopuses, and a variety of fish, including Arctic and sasffron cod, flounders, and sculpins.
Status
Abundance estimates are incomplete; estimates from the early 1980s suggest 450,000 animals in the Pacific region.
Ringed seal (Pusa hispida)
Distribution and Habitat
The ringed seal has a circumpolar distribution and is resident in North Pacific, North Atlantic and Arctic waters. There are five subspecies: the nominate subspecies hispida in the Arctic Ocean, Bering Sea and North Atlantic Ocean; botnica in the Baltic Sea including the Gulfs of Bothnia, Finland and Riga; ladogensis in Lake Ladoga, Russia; saimensis in Lake Saimaa, Finland and water bodies connected to it by passable rivers; and ochotensis in the Sea of Okhotsk and the northwestern Pacific Ocean.
Ringed seals use fast ice and sometimes dense pack ice for whelping, and numbers are strongly related to the relative permanence and density of ice in southern parts of their range. Pups are born in snow covered birth lairs, although ringed seals in the Okhotsk Sea regularly give birth on the exposed sea surface. Ringed seals have been seen within 2 km of the North Pole.
Natural History
Adult ringed seals are 99 - 157 cm in length and weigh 45 - 107 kg. Females are slightly smaller than males. The Baltic and Ladoga Lake subspecies are somewhat larger than the other subspecies. Pups are 55-65 cm in length and weigh 4-5 kg at birth. Pups are born with a long, white (greyish in the Saimaa Lake subspecies) lanugo that is moulted after 4-6 weeks. Adult coat colour is variable among subspecies, with rings on the sides and back. The subspecies hispida is illustrated above. Sexual maturity is attained in 5-7 years, males generally mature somewhat later than females. Breeding takes place in mid to late May. Pregnancy rates exceeding 95% of mature females have been reported. Gestation lasts 10.5-11 months. All subspecies (except P.h. ochotensis) give birth in snow lairs over breathing holes in fast ice, for protection against cold temperatures and predators such as polar bears. Longevity is reported to be 46 years. Diet varies seasonally and among subspecies, and is predominantly small schooling fish and crustaceans.
Status
The world population of ringed seals is estimated to be 6-7 million. The Lake Saimaa subspecies is listed on the IUCN Red List as Endangered. The Lake Ladoga and Baltic subspecies are listed as Vulnerable.
Threats to the Species
Ringed seals (P.h. hispida, and P.h. ochotensis) are hunted legally in the USA, Russia, Canada and Greenland. Maximum sustainable yield is estimated at approximately 7% of total population and the level of hunting being sustained up to 1999 is not believed to pose a threat. The Baltic subspecies was the focus of a hunt which was closed due to overexploitation in 1988, since which time hunting has been banned. Both lake-dwelling subspecies are affected by habitat destruction, disturbance and bycatch in fisheries. All subspecies are considered to be at risk from chemical pollutants, particularly the Baltic and freshwater subspecies.
Ribbon seal (Histriophoca fasciata)
Distribution and Habitat
The ribbon seal resides in North Pacific and Arctic waters, in particular the Sea of Okhotsk and Bering Sea. They associate with pack ice between January and May, but are believed to be pelagic during the rest of the year.
Natural History
Adult ribbon seals average 155-165 cm in length and 70-80 kg in weight. They may grow to 190 cm and 100 kg. Newborn pups are 80-90 cm long and 9-10 kg in weight. The darker of the animals pictured above is a typical male, and the lighter a typical female. Newborn pups have long, white hair that is moulted to the juvenile coat with blue-grey dorsal and silver-grey ventral colouration. Females are reported to be sexually mature at 2-5, and males at 3-6 respectively. gestation lasts 10.5-11 months and the pregnancy rate is reported to be 85%. Life expectancy is 22-26 years. The diet is primarily fish, as well as cephalopods and invertebrates.
Status
Abundance is not well known, but estimates are generally on the order of 200,000-250,000.
Threats to the Species
Some commercial prey species (e.g. pollock, Theragra chalcogramma) are important components of ribbon seal diet, and some ribbon seals are caught incidentally in commercial fisheries. Proposed petroleum exploration in parts of their range and they are legally hunted. The largest hunt is in Russia, and overexploitation has been a problem in the past.
Harbour seal (Phoca vitulina)
Distribution and Habitat
The harbour seal (which is known in the British Isles as the common seal) resides in North Pacific, North Atlantic, and Arctic waters. There are five named subspecies: P.v. concolor, P.v. mellonae, P.v. vitulina, P.v. stejnegeri, and P.v. richardii. While P.v. mellonae is the only harbour seal restricted to freshwater habitats (in northern Quebec), all harbour seals will enter estuaries and the lower reaches of rivers throughout their range.
Natural History
The colour and pattern of the harbour seal coat may vary between regions and even between individuals in a populations. Most conspicuous are the spots, rings and blotches, which are generally more numerous on the back than on the belly. Males range from 1.4-1.9 m, and weigh from 70-130 kg; females are slightly smaller. Harbour seals are often found alone or in small groups at sea, but are gregarious at haul-out sites. Females reach sexual maturity at approximately 3-5 years of age, males between 5 and 6. A single pup is born each year, from January to October, depending on location. Mating takes place after the pups are weaned at about 4 weeks. Harbour seals are opportunistic feeders and their diet varies with season, location, and prey availability.
Status
Population estimates of harbour seals are imprecise for many areas: P.v. concolor 40,000-100,000; P.v. mellonae 100-600; P.v. richardsi 380,000; P.v. vitulina 70,000; P.v. stejnegeri 4,000.
Threats to the Species
Because harbour seals are a coastal species, they are easily affected by habitat disturbance and alteration. Some populations are threatened by pollution, which may affect seal health and reproduction. Unknown numbers are caught incidentally in fishing gear, and some populations (e.g. P.v. stejnegeri in Japan) are significantly affected by interactions with fishing gear. The freshwater harbour seal (P.v. mellonae) may be potentially vulnerable because of its small population size, restricted range and susceptibility to disturbance. Bounties and culling programs have been initiated at various times throughout the last century. As recently as 1997 a culling program was undertaken in British Columbia, Canada, because of predation of declining salmon stocks. In recent years, a substantial decline in the Sable Island population off eastern Canada in the Northwest Atlantic has occurred, the cause of which is still unknown.
Walrus (Odobenus rosmarus)
Distribution and Habitat
The walrus resides in North Pacific, North Atlantic, and Arctic waters. There are three subspecies: the nominate subspecies rosmarus in the North Atlantic, Barents, eastern Canadian Arctic and western Kara Seas; divergens in the Chukchi and Bering Seas and North Pacific south to Kamchatka and Bristol Bay; and laptevi in the Russian Arctic from the western reaches of the East Siberian Sea, the Laptev Sea and western Kara Sea. Now largely restricted to northern latitudes it was once much more widely distributed, particularly the Atlantic walrus which ranged as far south as Cape Cod in North America before hunting wiped out southern populations. Primarily associated with pack ice in winter, walruses will also haul out on land.
Natural History
Atlantic walrus males average 3.0 m in length and weigh approximately 800-900 kg. Pacific walrus males are somewhat larger, averaging 3.2 m and approximately 1200 kg. Females are generally smaller. Laptev walruses are intermediate between the other subspecies (but more similar to Pacific walruses of which some consider them to be a population). Although they appear to be naked, the brown skin is covered with short, coarse hair. Both sexes have enlarged upper canine teeth which appear as external tusks, and are larger in males. Males are sexually mature at approximately 15. Some females may mature by age 4, but age 7 - 8 is usual. Gestation lasts 15 months and lactation 1 to 2 years. Females may produce a pup every other year, but every third year is considered usual. Molluscs are the main food, constituting 95% of the diet by numbers and mass. Other benthic invertebrates and fish are also taken. Some individuals are known to prey on seals, particularly ringed seals. Walruses may live up to 40 years.
Status
The Pacific walrus is most numerous, with the present population estimated to be between 200,000 and 300,000. It is thought that the Laptev walrus population numbers 5,000 - 10,000. The Atlantic walrus is believed to number approximately 15,000, although estimates for Russian populations are out of date. The Laptev walrus is entered in the IUCN Red List as Insufficiently Known.
Threats to the Species
Pacific walruses are legally hunted in Russia, and the USA and Atlantic walruses are legally hunted in Canada and Greenland. The IUCN Seal Specialist Group has stated that "overexploitation of local stocks is one of the major threats in some areas." Poaching is known to occur on all subspecies and is thought to be at unsustainable levels for some populations. Proposed mineral and petroleum exploitation pose threats both directly, and through the increased risk of disturbance and poaching that attend increased human activity. Harvesting of Arctic molluscs on which walruses feed has been proposed in some areas and may constitute a risk to the forage base of affected populations.
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