Haul-out behaviour of ringed and bearded seals in relation to defence against surface predators

The ringed seal, Phoca hispida, hauls out at the edge of self-maintained breathing holes or narrow cracks, either in fast ice or in the centre of large floes in pack ice, apparently because this reduces its vulnerability to capture by polar bears, Ursus maritimus. Antipredator behaviour of ringed seals at haul-out sites also includes lying facing both their breathing hole and downwind, and vigilance. The much larger bearded seal, Erignathus barbatus, hauls out on the edges of wide leads or large holes in the ice, or on the points of small ice floes, and also faces both the water and downwind. Ice-associated seals which are not threatened by surface predators do not show these behaviour patterns.

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Characteristics of ringed seal, Phoca hispida, subnivean structures and breeding habitat and their effects on predation

Canadian Journal of Zoology ◽

10.1139/z96-100 ◽

1996 ◽

Vol 74 (5) ◽

pp. 858-874 ◽

Cited By ~ 43

Author(s):

C. M. Furgal ◽

K. M. Kovacs ◽

S. Innes

Keyword(s):

Snow Depth ◽

Function Analysis ◽

Ringed Seal ◽

Breeding Habitat ◽

Phoca Hispida ◽

Ringed Seals ◽

Arctic Foxes ◽

Ridge Height ◽

Length Width ◽

Fast Ice

Characteristics of ringed seal (Phoca hispida) subnivean structures and breeding habitat were quantified and their potential influence on predation success by polar bears (Ursus maritimus), arctic foxes (Alopex lagopus), and humans on ringed seals was investigated in Admiralty Inlet and Strathcona Sound, Northwest Territories. A total of 237 ringed seal structures were located between April and June 1991–1993 using trained dogs. Ringed seal lairs and breathing holes were concentrated in areas of deep snow, and were associated with large, thick ice ridges. Only a small percentage of the available fast-ice habitat had sufficient snow depth for lair construction each year. A discriminant function analysis used to classify structures located in 1992, using a combination of structural and habitat measurements, correctly classified 70% of structures located in 1991 and 1993 into functional groups. The length, width, internal height, and level of "tiggak," the odour of rutting male ringed seals, associated with structures were the most important descriptors separating structure types. Seventy-three percent of structures located in the study were undisturbed by predators. The mean length and width of structures entered by predators were significantly greater than those of undisturbed structures. Polar bear success decreased as snow depth and the thickness of the roof covering the structures increased. The conditions necessary for successful arctic fox predation are unclear. Inuit hunters attacked structures close to ice ridges, and ridge height and snow depth influenced their success. All predators attacked lairs having the odour of rutting male ringed seals less often than structures with no male odour.

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Distribution of populations of ringed seal Phoca hispida and bearded seal Erignathus barbatus in shallow and average-deep areas of the southwestern part of the Kara Sea in summer 2015

Doklady Biological Sciences ◽

10.1134/s0012496617030085 ◽

2017 ◽

Vol 474 (1) ◽

pp. 114-119

Author(s):

Yu. I. Goryaev ◽

N. G. Chelintsev ◽

A. V. Ezhov ◽

P. R. Makarevich ◽

D. G. Ishkulov

Keyword(s):

Ringed Seal ◽

Kara Sea ◽

Phoca Hispida ◽

Bearded Seal ◽

Southwestern Part ◽

Erignathus Barbatus

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The ringed seal (Phoca hispida) in the western Russian Arctic

NAMMCO Scientific Publications ◽

10.7557/3.2981 ◽

1998 ◽

Vol 1 ◽

pp. 63 ◽

Cited By ~ 4

Author(s):

Stanislav E Belikov ◽

Andrei N Boltunov

Keyword(s):

Barents Sea ◽

White Sea ◽

Ringed Seal ◽

Kara Sea ◽

Russian Arctic ◽

The White Sea ◽

Phoca Hispida ◽

Ringed Seals ◽

The Barents Sea ◽

Fast Ice

This paper presents a review of available published and unpublished material on the ringed seal (Phoca hispida) in the western part of the Russian Arctic, including the White, Barents and Kara seas. The purpose of the review is to discuss the status of ringed seal stocks in relation to their primary habitat, the history of sealing, and a recent harvest of the species in the region. The known primary breeding habitats for this species are in the White Sea, the south-western part of the Barents Sea, and in the coastal waters of the Kara Sea, which are seasonally covered by shore-fast ice. The main sealing sites are situated in the same areas. Female ringed seals become mature by the age of 6, and males by the age of 7. In March-April a female gives birth to one pup in a breeding lair constructed in the shore-fast ice. The most important prey species for ringed seals in the western sector of the Russian Arctic are pelagic fish and crustaceans. The maximum annual sealing level for the region was registered in the first 70 years of the 20th century: the White Sea maximum (8,912 animals) was registered in 1912; the Barents Sea maximum (13,517 animals) was registered in 1962; the Kara Sea maximum (13,200 animals) was registered in 1933. Since the 1970s, the number of seals harvested has decreased considerably. There are no data available for the number of seals harvested annually by local residents for their subsistence.

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The numbers of ringed seals (Phoca hispida) in Baffin Bay and associated waters

NAMMCO Scientific Publications ◽

10.7557/3.2988 ◽

1998 ◽

Vol 1 ◽

pp. 181 ◽

Cited By ~ 4

Author(s):

Michael C S Kingsley

Keyword(s):

Polar Bear ◽

Approximate Model ◽

Ringed Seal ◽

Phoca Hispida ◽

Age Classes ◽

Field Metabolic Rate ◽

Baffin Bay ◽

Ringed Seals ◽

Pack Ice ◽

Seal Population

The size of the population of ringed seals (Phoca hispida) inhabiting Baffin Bay and associated waters was estimated by two methods. An approximate model of the energetics of the polar bear (Ursus maritimus) estimated an energetic need of about 16,000 MJ/bear per year. Modelled estimates of the energetic yield of a ringed seal population showed that a stable standing population of 140-170 ringed seals per bear would be needed to provide that much energy, assuming that all mortalities were due to polar bear predation. This result was sensitive to assumptions about the Field Metabolic Rate (FMR) of the bears and the energetic yield of individual ringed seals, but less sensitive to assumptions about relative incidence of predation on different age classes of seal or the age structure of the polar bear population. Estimated sizes of polar bear populations in Baffin Bay and associated waters (total about 4,025), and of the standing population needed to support an estimated hunter kill of 100,000 yielded a population estimate of, very roughly, 1.2 million ringed seals. Estimates of ice areas and of the density of hauled out seals from aerial surveys were used to generate another approximate figure for the ringed seal population, which was about the same. The density of seals in the pack-ice area of Baffin Bay, which is imperfectly known, has a large influence on the latter estimate.

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Aspects of Predation of Seals by Polar Bears

Journal of the Fisheries Research Board of Canada ◽

10.1139/f77-169 ◽

1977 ◽

Vol 34 (8) ◽

pp. 1126-1129 ◽

Cited By ~ 156

Author(s):

Ian Stirling ◽

W. Ralph Archibald

Keyword(s):

High Arctic ◽

Ursus Maritimus ◽

Polar Bears ◽

Phoca Hispida ◽

Ringed Seals ◽

Arctic Foxes ◽

Large Numbers ◽

Erignathus Barbatus ◽

Western Arctic ◽

Bearded Seals

Data were collected from 227 ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) killed by polar bears (Ursus maritimus) in the western arctic and the eastern high arctic. During periods of high ringed seal productivity, pups constituted at least half of the seals killed in both areas during the spring. Bearded seals were taken less often than ringed seals in both areas but were more important as prey to polar bears in the western arctic. Carcass utilization was significantly higher in the eastern high arctic than in the western arctic although the reason was not apparent. Scavenging of unutilized seal remains is probably of great importance to the survival of large numbers of arctic foxes (Alopex lagopus) through the winter. Key words: Ursus maritimus, Phoca hispida, Erignathus barbatus, predation, interspecific relationships, Arctic Ocean mammals

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Distribution and abundance of ringed (Phoca hispida) and bearded seals (Erignathus barbatus) in western Hudson Bay

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f96-346 ◽

1997 ◽

Vol 54 (4) ◽

pp. 914-921 ◽

Cited By ~ 12

Author(s):

N J Lunn ◽

I Stirling ◽

S N Nowicki

Keyword(s):

Polar Bear ◽

Hudson Bay ◽

Phoca Hispida ◽

Current Estimate ◽

Ringed Seals ◽

Erignathus Barbatus ◽

The Mean ◽

Western Hudson Bay ◽

The Relationship ◽

Bearded Seals

We flew a medium-altitude, systematic, strip-transect survey for ringed (Phoca hispida) and bearded seals (Erignathus barbatus) over western Hudson Bay in early June 1994 and 1995. The mean density (per square kilometre) of ringed seals hauled out on the ice was four times higher in 1995 (1.690) than in 1994 (0.380). The 1994 survey appeared to underestimate seal abundance because it was flown too late. Ringed seals preferred high ice cover habitat (6 + /8 ice) and, within this habitat, favoured cracking ice and large floes. We found no consistent effect of either wind or cloud cover on habitat preference. We estimated a total of 1980 bearded seals and 140<|>880 ringed seals hauled out on the sea ice in June 1995. A recent review of the relationship between ringed seal and polar bear (Ursus maritimus) populations suggests that a visible population of this size should support a population of up to 1300 polar bears, which is in general agreement with the current estimate of 1250-1300 bears in western Hudson Bay.

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Population parameters of ringed seals (Phoca hispida Schreber, 1775) in the Svalbard area

Canadian Journal of Zoology ◽

10.1139/z87-162 ◽

1987 ◽

Vol 65 (4) ◽

pp. 1021-1027 ◽

Cited By ~ 38

Author(s):

Christian Lydersen ◽

Ian Gjertz

Keyword(s):

Sex Ratio ◽

Ringed Seal ◽

Adult Males ◽

Population Parameters ◽

Phoca Hispida ◽

Age Class ◽

Ringed Seals ◽

Males And Females ◽

The Mean ◽

Sexually Mature

Samples were taken from 284 ringed seals (Phoca hispida) in the Svalbard area during April–July 1981 and March–April 1982. The age of 283 seals was determined by reading annuli in the cementum of the canine teeth. The mean age of the males was 11.3 years, and of the females, 14.9 years. Females were found to be significantly older than males. The mean length of sexually mature ringed seals was 128.9 cm for both sexes. The mean weight of adult males and females was 53.5 and 61.4 kg, respectively. Females were found to be significantly heavier than males. The sex ratio was 47.8% males and 52.2% females. Studies of microscopic sections of testis and epididymis from ringed seal males showed that 63, 75, and 80% of 5-, 6-, and 7-year-old animals, respectively, were sexually mature. The weights of testis and epididymis, diameters of tubuli, and the size of testis all showed a marked increase in the 5-year age-class. Macroscopic sections of ovaries from ringed seal females showed that 20, 60, and 80% of 3-, 4-, and 5-year-old animals, respectively, were sexually mature. The size of the ovaries showed a marked increase in the 5-year age-class. The ovulation rate of ringed seals from Svalbard was calculated to be 0.91.

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The breeding habitat of the ringed seal (Phoca hispida). The birth lair and associated structures

Canadian Journal of Zoology ◽

10.1139/z75-155 ◽

1975 ◽

Vol 53 (9) ◽

pp. 1297-1305 ◽

Cited By ~ 125

Author(s):

Thomas G. Smith ◽

Ian Stirling

Keyword(s):

Ursus Maritimus ◽

Ringed Seal ◽

Breeding Habitat ◽

Polar Bears ◽

Alopex Lagopus ◽

Phoca Hispida ◽

Arctic Foxes ◽

Different Types ◽

Amundsen Gulf

The subnivean lairs of the ringed seal (Phoca hispida) were studied in the Amundsen Gulf and Prince Albert Sound areas from 1971 through 1974. The structure of several different types of lairs are described. The existence of a birth-lair complex consisting of several closely adjacent lairs appears likely. The spacial distribution of lairs and lair types found on refrozen leads and in pressure ridges is described. Lairs were more abundant in inshore ice than in offshore ice. The function of subnivean lairs appears to be to provide thermal shelter, especially for neonate seals, and protection from predation by arctic foxes (Alopex lagopus) and polar bears (Ursus maritimus).

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The caloric value of whole ringed seals (Phoca hispida) in relation to polar bear (Ursus maritimus) ecology and hunting behavior

Canadian Journal of Zoology ◽

10.1139/z75-117 ◽

1975 ◽

Vol 53 (8) ◽

pp. 1021-1027 ◽

Cited By ~ 128

Author(s):

Ian Stirling ◽

Eoin H. McEwan

Keyword(s):

Total Body Water ◽

Polar Bear ◽

Fat Body ◽

Ursus Maritimus ◽

Ringed Seal ◽

Body Water ◽

Phoca Hispida ◽

Hunting Behavior ◽

Wet Weight ◽

Total Body

Throughout its circumpolar range, the polar bear (Ursus maritimus) feeds predominantly on the ringed seal (Phoca hispida). Despite seasonal variation in availability and distribution of seals, polar bears prefer to eat mainly the fat, often leaving substantial portions of seal meat and blubber. In the present study, 12 seals were minced and analyzed for water, fat, protein, and ash contents. The percentage composition varied from 23 to 58% protein, 34 to 76% fat, 2 to 5.5% ash, and 47.4 to 69.5% total body water. The caloric values varied from 2.3 to 5.3 kcal/g wet weight. Relationships between total body water and fat (%), body water (litres) and protein (kg) are presented. These results are discussed in relation to the ecology and hunting behavior of the polar bear.

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