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

1998 ◽  
Vol 1 ◽  
pp. 181 ◽  
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.

scholarly journals A Distinctive Large Breeding Population of Ringed Seals (Phoca hispida) Inhabiting the Baffin Bay Pack Ice

ARCTIC ◽  
1983 ◽  
Vol 36 (2) ◽  
Author(s):  
K.J. Finley ◽  
G.W. Miller ◽  
R.A. Davis ◽  
W.R. Koski
Keyword(s):  
Breeding Population ◽  
Phoca Hispida ◽  
Baffin Bay ◽  
Ringed Seals ◽  
Pack Ice

scholarly journals Distribution, abundance and biology of ringed seals (Phoca hispida): an overview

1998 ◽  
Vol 1 ◽  
pp. 9 ◽  
Author(s):  
Randall R Reeves
Keyword(s):  
Polar Bear ◽  
Late Summer ◽  
Early Summer ◽  
Ringed Seal ◽  
Late Spring ◽  
Late Winter ◽  
Polar Cod ◽  
World Population ◽  
Phoca Hispida ◽  
Ringed Seals

The ringed seal (Phoca hispida) has a circumpolar Arctic distribution. Because of its great importance to northern communities and its role as the primary food of polar bears (Ursus maritimus) the ringed seal has been studied extensively in Canada, Alaska, Russia, Svalbard and Greenland as well as in the Baltic Sea and Karelian lakes. No clear-cut boundaries are known to separate ringed seal stocks in marine waters. Adult seals are thought to be relatively sedentary, but sub-adults sometimes disperse over long distances. Stable ice with good snow cover is considered the most productive habitat although production in pack ice has been little studied. Populations appear to be structured so that immature animals and young adults are consigned to sub-optimal habitat during the spring pupping and breeding season. Annual production in ringed seal populations, defined as thepup percentage in the total population after the late winter pupping season, is probably in the order of 18-24%. Most estimates of maximum sustainable yield are in the order of 7%.The world population of ringed seals is at least a few million. Methods of abundance estimation have included aerial surveys, dog searches and remote sensing of lairs and breathing holes, acoustic monitoring, correlation analysis by reference to sizes of polar bear populations, and inference from estimated energy requirements of bear populations. Aerial strip survey has been the method of choice for estimating seal densities over large areas. Adjustment factors to account for seals not hauled out at the time of the survey, for seals that dove ahead of the aircraft, and for seals on the ice within the surveyed strip but not detected by the observers, are required for estimates of absolute abundance.Male and female ringed seals are sexually mature by 5-7 years of age (earlier at Svalbard). Pupping usually occurs in March or early April and is followed by 5-7 weeks of lactation. Breeding takes place in mid to late May, and implantation is delayed for about 3 months. In at least some parts of their range, ringed seals feed mainly on schooling gadids from late autumn through early spring andon benthic crustaceans and polar cod (Boreogadus saida) from late spring through summer. Little feeding is done during the moult, which takes place in late spring and early summer. Pelagic crustaceans offshore and mysids inshore become important prey in late summer and early autumn in some areas. Ringed seals have several natural predators, the most important of which is the polar bear in most arctic regions. Arctic foxes (Alopex lagopus) kill a large percentage of pups in someareas.From a conservation perspective, the ringed seal appears to be secure. Levels of exploitation of arctic populations have usually been considered sustainable, except in the Okhotsk Sea. Large fluctuations in production of ringed seals in the Beaufort Sea and Amundsen Gulf are thought to be driven by natural variability in environmental conditions. While concern has been expressed about thepotential impacts of industrial activity and pollution on ringed seals, such impacts have been documented only in limited areas. Because of their ubiquitous occurrence and availability for sampling, ringed seals are good subjects for monitoring contaminant trends in Arctic marine food chains. 

scholarly journals Exploitation of ringed seals (Phoca hispida) in Greenland

1998 ◽  
Vol 1 ◽  
pp. 130 ◽  
Author(s):  
Jonas Teilmann ◽  
Finn O Kapel
Keyword(s):  
Great Majority ◽  
Open Water ◽  
Ringed Seal ◽  
Phoca Hispida ◽  
Age Classes ◽  
Ringed Seals ◽  
Original Culture ◽  
Term Variation ◽  
Northern Regions

The ringed seal (Phoca hispida) is the most important game for the Inuit hunters of Greenland, providing many of the basic needs in the original culture. It is distributed all around Greenland with the main distribution north of 69°N on the west coast and north of 66°N on the east coast. During 1974-76, studies were conducted in the most important ringed seal catching area, Upernavik, Northwest Greenland, and a total of 7,089 ringed seals were sampled. The methods used for catching ringed seals were categorised into five different groups. The most common hunting method used in the municipality of Upernavik during 1974-76 was netting under the ice, accounting for almost half of the total annual catch. Seals shot on the ice and seals shot at the ice edge accounted for one fifth and one tenth of the annual catch, respectively. In this region seals shot in open water made up about one fifth of the annual catch of ringed seals, while netting in open water contributed only a few percent.Of the seals sampled in Upernavik in 1974-76, 60% were males and 40% were females. In the ringed seal samples collected all around Greenland in the 1980s and 1990s the males comprised 56% and the females 44% (n=923). Similar ratios were found for all age classes and for all hunting methods suggesting either a skewed sex ratio in the ringed seal stock(s) around Greenland or a differencein availability to the hunters of male and female ringed seals. In tagging experiments a higher mobility was found for females than for males, which suggests differences in the behaviour of the two sexes.Catch and trade statistics on ringed seals are reviewed and evaluated for the period of 1954 until 1994, and the seasonal and regional variation is examined. The peak season for ringed seal hunting in Greenland as a whole is from January through May. This is particularly evident for the northern regions, where relatively few ringed seals are taken during the open water season from June to September. In the southern regions, however, the great majority of ringed seals are caught in openwater.In all regions, the catch of ringed seals showed great annual and long-term variation. The variations were not identical in all regions, but similar trends were found for Northwest and Central West, and for Southwest and South. From 1954 to 1994 there was a general, significant increase in the reported catches of ringed seals in west Greenland. For Greenland overall, the catch of ringed seals wasaround 43,000 per year in the 1950s, peaked in the late 1970s at almost 100,000 per year, but since decreased to about 70,000 in the early 1990s.

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

1991 ◽  
Vol 69 (7) ◽  
pp. 1857-1861 ◽  
Author(s):  
Michael C. S. Kingsley ◽  
I. Stirling
Keyword(s):  
Ursus Maritimus ◽  
Ringed Seal ◽  
Antipredator Behaviour ◽  
Phoca Hispida ◽  
Bearded Seal ◽  
Ringed Seals ◽  
Pack Ice ◽  
Erignathus Barbatus ◽  
Fast Ice ◽  
Ice Floes

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.

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

1997 ◽  
Vol 54 (4) ◽  
pp. 914-921 ◽  
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.

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

1987 ◽  
Vol 65 (4) ◽  
pp. 1021-1027 ◽  
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.

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

1975 ◽  
Vol 53 (8) ◽  
pp. 1021-1027 ◽  
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.

RINGED SEAL (PHOCA HISPIDA) BREEDING IN THE DRIFTING PACK ICE OF THE BARENTS SEA

1999 ◽  
Vol 15 (2) ◽  
pp. 595-598 ◽  
Author(s):  
Oystein Wiig ◽  
Andrew E. Derocher ◽  
Stanislav E. Belikov
Keyword(s):  
Barents Sea ◽  
Ringed Seal ◽  
Phoca Hispida ◽  
The Barents Sea ◽  
Pack Ice

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

1996 ◽  
Vol 74 (5) ◽  
pp. 858-874 ◽  
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.

Lactation in the Ringed Seal (Phoca hispida)

1991 ◽  
Vol 48 (12) ◽  
pp. 2471-2476 ◽  
Author(s):  
M. O. Hammill ◽  
C. Lydersen ◽  
M. Ryg ◽  
T. G. Smith
Keyword(s):  
Growth Rate ◽  
Weight Loss ◽  
Ringed Seal ◽  
Energy Reserves ◽  
Stored Energy ◽  
Phoca Hispida ◽  
Cross Sectional ◽  
Ringed Seals ◽  
Pup Growth ◽  
Female Weight

Length of lactation, pup growth rate, and female weight loss in ringed seals (Phoca hispida) were estimated using cross-sectional data from the Canadian and Norwegian Arctic. At birth the pups had a standard length of 63.4 cm (SE = 1.3, N = 11) and weighed 5.4 kg (SE = 0.4, N = 6). Weaning occurred approximately 39 d (range 36–41 d) after birth at an estimated length of 88.4 cm (SE = 0.65, N = 96) and an estimated weight of 22.1 kg, resulting in an increase in length of 0.64 cm∙d−1 and a weight change of 0.43 kg∙d−1. Regression of female weight on the number of days after the nominal date of birth for each region indicated that the postpartum female weighed 81.2 kg and lost 0.64 kg∙d−1 (95% CI = ±0.20). During lactation, female weight declined by an estimated 32%, with much of the loss occurring from the blubber. Analyses of stomachs indicated that ringed seals supplemented stored energy reserves by feeding during lactation.

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