Pagophilus groenlandicus (Erxleben, 1777)
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publication ID |
https://doi.org/ 10.5281/zenodo.6607185 |
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DOI |
https://doi.org/10.5281/zenodo.6607261 |
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persistent identifier |
https://treatment.plazi.org/id/464F694F-FFA7-A85A-FF3A-D276914BF967 |
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treatment provided by |
Diego |
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scientific name |
Pagophilus groenlandicus |
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Harp Seal
Pagophilus groenlandicus View in CoL
French: Phogue du Groenland / German: Sattelrobbe / Spanish: Foca pia
Other common names: Greenland Seal, Saddleback Seal
Taxonomy. Phoca groenlandica Erxleben, 1777 View in CoL ,
“in Groenlandia [= Greenland] et Newfoundland.”
Although D. W. Rice in 1998 recognized the subspecies oceanicus breeding in the White Sea, it 1s more common to refer to distinct populations or stocks based on morphological, genetic, and behavioral differences. Monotypic.
Distribution. Subarctic in N Atlantic and Arctic oceans, from Davis Strait, Baffin I, and N Hudson Bay, to Newfoundland and Gulf of Saint Lawrence (Canada) and E to Greenland, Iceland, N Norway, White Sea, and Barents and Kara seas (N Russia). View Figure
Descriptive notes. Total length ¢.160-170 cm; weight ¢.120-135 kg. Newborns are c.85 cm in length and weigh c.4 kg. Male Harp Seals can be slightly larger than females. Harp Seals are moderate-sized phocid carnivores, with robust bodies and relatively small heads. Neonates are born with a thick white lanugo (fine, soft hair) that begins to molt at about three weeks old and is replaced by short, silvery pelage with scattered small spots. Juvenile Harp Seals have similar pelages to weaned offspring and then a faint harp pattern (two longitudinal dark bands on flanks that run to just behind armpits and then upward to unite on top of shoulders) begins to appear as they age. It becomes dark black near physical maturity, particularly in males. Head of adult Harp Seals is also black.
Habitat. Subarctic waters and Arctic regions of the North Atlantic Ocean, particularly tied to the southern and northern limits of seasonal pack ice. Harp Seals are closely associated with the southern extent of seasonal sea ice in late winter and spring, where they haul-out to give birth and then later to molt. They appear to be pelagic for the rest of the year because they feed and range widely in open waters and marginal sea ice.
Food and Feeding. Harp Seals have a diverse diet of fish and invertebrates, but their primary prey is a few species of euphausiid crustaceans (Thyanoessa spp.) and smaller fish like capelin ( Mallotus villosus), sand eel ( Ammodytes sp. ), and Arctic cod ( Boreogadus sada and Arctogadus glacialis). Harp seals are relatively shallow divers, usually to less than 100 m, but they have been recorded descending to c.400 m. Overall, deepest dives occur during the day in winter. When actively feeding after breeding and molting periods, Harp Seals often congregate in relatively large groups along ice edges and other oceanographic features where prey is concentrated.
Breeding. Female Harp Seals give birth to a single offspring beginning in late February through mid-March. Young are nursed for c.12 days, after which they are abruptly weaned. Adult males patrol ice edges and then mate with females when they enter the water to start foraging. Male Harp Seals appear to be promiscuous, and there is little sexual dimorphism in size or appearance. After a female has conceived, the embryo develops briefly and then is dormant for c.2-3 months before it attaches to the uterine wall and fetal development resumes. Females are sexually mature at 4-7 years old, and 85-90% of them can give birth each year after that. Males are sexually mature at c¢.7-8 years old. During the breeding season, Harp Seals aggregate in large numbers—thousands or more—on edges of seasonalfast ice (ice fastened to land). Although concentrated together there, they are not particularly social and are dispersed primarily as mother—offspring pairs, with an occasional male investigating the status of a female.
Activity patterns. Harp Seals start to molt in early April and spend more time hauled out then and eatlittle or fast entirely for the next several weeks. When foraging between breeding and molting, they are highly active and make repeated dives to depths of up to 400 m (usually less) for c.16 minutes/dive. Male Harp Seals appear to be particularly vocal underwater during the breeding season,either to attract females or to repel male competitors.
Movements, Home range and Social organization. When not hauled out on the ice to breed and molt, Harp Seals appear to be highly mobile and migratory. They can travel large distances—up to 8000 km—while foraging during the year, either alone or occasionally appearing in groups of several dozen. Harp Seals often occur as vagrants outside their normal distribution, south to Virginia (USA), Faroe Islands, Denmark, the UK, Germany, France, and even Spain.
Status and Conservation. Classified as Least Concern on The IUCN Red List. Humans have hunted Harp Seals throughout their distribution for thousands of years and into current times. The earliest records of harvest of Harp Seals in the north-western Atlantic Ocean are from Basque whalers in the 1500s, followed by French settlers along the Saint Lawrence River, Canada, who used land-based netting techniques in the mid-1600s. By the mid-1700s, French-Canadians harvest an estimated 6000 Harp Seals/ year for oil (estimated at 500 tons of oil/year) and pelts, and English settlers in Newfoundland harvested 7000-12,800 Harp Seals/year. As ship-based sealing developed in the 1800s, harvest of Harp Seals rose substantially to ¢.117,000 ind/year, and in 1818-1862, annual harvest in many of those years was estimated at ¢.500,000 individuals, peaking at 640,000-740,000 ind/year. During this period, an estimated 18:3 million Harp Seals were harvested in the north-western Atlantic Ocean. Total harvest in the north-eastern part of the distribution of the Harp Seal in 1860-1900 was estimated at 12-8 million individuals. In the 20" century, Harp Seals became valued more for their pelts than their oil and harvests generally decreased. About one million seals were killed in the north-western Atlantic Ocean in 2004-2007, primarily young less than three days old, mostly for their pelts but also for oil and bacula (penis bone). Harp Seals are concentrated in three major population centers. Thefirst stock is in the White Sea and Barents Sea (East Ice) with ¢.2,000,000 individuals in 2005, the second (West Ice) in the Greenland Sea near Jan Mayen with ¢.635,000 individuals in 2005, and the third, the largest, in the north-western Atlantic Ocean near southern Labrador, Newfoundland, and Gulf of Saint Lawrence with 5-5 million individuals in 2007. Populations in the three main reproductive areas have apparently declined because of continued harvest, particularly in Canadian waters of the north-western Atlantic stock where harvest levels increased in the 2000s and may be exceeding sustainable levels by 1-5-5-9 times. There are no recent estimates of range-wide abundance of the Harp Seal, although it is the most abundant species of seals in the Northern Hemisphere and may still number close to eight million individuals. Commercial fisheries may be deceasing prey availability for Harp Seals, and bycatch in fishing nets has been problematic off the northern coast of Norway, for example, where an estimated 100,000 individuals in 1987 and 21,474 individuals in 1988 were killed in fishing nets. Changes in the extent of sea ice and seasonal dynamics ofits coverage are likely having effects on this ice-breeding obligate.
Bibliography. Kovacs (1987 2008b), Kovacs & Lavigne (1985), Lavigne (2009), Lavigne & Kovacs (1988), Perry & Terhune (1999), Rice (1998).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
