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

1975 ◽  
Vol 53 (9) ◽  
pp. 1297-1305 ◽  
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).

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.

Evironmental threats to marine mammals in the Canadian Arctic

Polar Record ◽  
1983 ◽  
Vol 21 (134) ◽  
pp. 433-449 ◽  
Author(s):  
Ian Stirling ◽  
Wendy Calvert
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Marine Mammals ◽  
Canadian Arctic ◽  
Ursus Maritimus ◽  
The Arctic ◽  
Polar Bears ◽  
Alopex Lagopus ◽  
Arctic Foxes ◽  
The Arctic Ocean

The Arctic Ocean is the home of three major groups of mammals that depend on the sea for survival and show varying degrees of adaptation for maritime life. Most fully adapted are the whales (Cetacea), which never leave the water, and the seals and walruses (Pinnipedia) that feed entirely at sea but emerge onto land or ice for pupping and basking. Less exclusively marine are two species of the order Carnivora—Polar Bears (Ursus maritimus), that seldom live far from the sea because they feed almost entirely upon seals, and Arctic Foxes (Alopex lagopus), some of which move out onto the sea ice during the winter, mainly to scavenge on the remains of seals killed by Polar Bears.

Aspects of Predation of Seals by Polar Bears

1977 ◽  
Vol 34 (8) ◽  
pp. 1126-1129 ◽  
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

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.

Relationships between estimates of ringed seal (Phoca hispida) and polar bear (Ursus maritimus) populations in the Canadian Arctic

1995 ◽  
Vol 52 (12) ◽  
pp. 2594-2612 ◽  
Author(s):  
Ian Stirling ◽  
Nils Are Øritsland
Keyword(s):  
Metabolic Rate ◽  
Population Size ◽  
Polar Bear ◽  
Population Level ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Phoca Hispida ◽  
Ringed Seals ◽  
Reproductive Rates ◽  
The Relationship

Analysis of estimates of population size of ringed s,eals (Phoca hispida) and polar bears (Ursus maritimus) from several areas indicated that estimates of one predicted the range of expected population size of the other in areas where ringed seals constitute the primary prey. In some areas, the closeness of this relationship indicates where estimates of either seals or bears may be inaccurate. The number of seals required to support a population of polar bears of predetermined size was estimated independently using both behavioral and energetic data. Behavioral estimates of the number of seals killed may overestimate energetic requirements and vice versa. Predation and energy matrices indicated that high levels of predation on seals are sustainable only if most animals killed are young-of-the-year. The field metabolic rate of the polar bear appears to be about twice the basal metabolic rate. Densities of seals vary in response to overall productivity of the ecosystem in different areas, and fluctuations in their numbers and reproductive rates between years can be used to monitor changes in productivity of the ecosystem. These changes also cause variation in productivity of bears, which indicates the sensitivity, at the population level, of the relationship between ringed seals and polar bears.

Midsummer observations on the behavior of wild polar bears (Ursus maritimus)

1974 ◽  
Vol 52 (9) ◽  
pp. 1191-1198 ◽  
Author(s):  
Ian Stirling
Keyword(s):  
Diurnal Rhythm ◽  
Intraspecific Competition ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Phoca Hispida ◽  
Devon Island ◽  
Adult Females ◽  
Ringed Seals ◽  
Single Animal ◽  
The Mean

Wild polar bears (Ursus maritimus) were observed from Caswall Tower, Devon Island (74°43′ N; 91°10′ W), from 24 July to 8 August 1973. A total of 602.7 bear hours of observations was recorded. Two types of hunting were observed, stalking and still-hunting. Of 288 hunts observed, 65 (22.6%) were stalks and 233 (77.4%) were still-hunts. All cubs observed hunted, but they exhibited great variety in patience and apparent skill. Scavenging and intraspecific competition for possession of kills were observed. When threatened, adult females with cubs were not subordinate to tears of any other age or sex classes. A diurnal rhythm was recorded in which bears slept most during the latter third of the 24-h cycle and least in the first third. The average of 17 sleeps longer than 60 min was 465 ± 301.3 min.Basking ringed seals (Phoca hispida) alternated between lying flat and raising their heads to look about for predators. The mean duration of the lying and looking phases was 26.3 and 7.0 s respectively (n = 591 and 580). The variation between individual seals was greater than within individuals. If a group of seals hauled out together, all individuals maintained watchful behavior; no single animal acted as a "sentry" for the others.

Predation of ringed seal pups (Phoca hispida) by the arctic fox (Alopex lagopus)

1976 ◽  
Vol 54 (10) ◽  
pp. 1610-1616 ◽  
Author(s):  
Thomas G. Smith
Keyword(s):  
Energy Budget ◽  
Ringed Seal ◽  
The Arctic ◽  
Maintenance Energy ◽  
Arctic Fox ◽  
Alopex Lagopus ◽  
Phoca Hispida ◽  
Important Predator ◽  
First Time

The arctic fox (Alopex lagopus), commonly assigned the role of scavenger of marine mammal remains left by polar hears (Ursus maritimus), is for the first time quantitatively described as an important predator of the pups of the ringed seal (Phoca hispida). Foxes enter and kill the seal pups in their subnivean birth lairs. In no case were any seals other than pups killed by foxes. While predation was seen to vary over the 3 years of study, an average pup predation of 26.1% in nearshore sea ice is estimated. Estimates of the contribution of seal pups to the fox energy budget are calculated. Newborn seal pups contribute a maximum of 45.2 and a minimum of 30.2 days of maintenance energy. Almost weaned pups provide a maximum of 341.5 and a minimum of 227 days of maintenance energy.

Diving in ringed seal (Phoca hispida) pups during the nursing period

1993 ◽  
Vol 71 (5) ◽  
pp. 991-996 ◽  
Author(s):  
Christian Lydersen ◽  
Mike O. Hammill
Keyword(s):  
Short Duration ◽  
Average Duration ◽  
Dive Duration ◽  
Ringed Seal ◽  
Young Age ◽  
White Coat ◽  
Polar Bears ◽  
Phoca Hispida ◽  
Study Activity ◽  
The Mean

In this study, activity and diving performance of nursing ringed seal (Phoca hispida) pups were quantified using time–depth recorders. A total of 1040 h of activity, including 7506 diving cycles, was collected from three female pups. The pups spent 50.3% of their time in the water and 49.7% hauled out on the ice. When the pups were in the water, 20.5% of the time was spent actively diving, while 79.5% of the recorded wet time was spent at the surface. Most of the dives were shallow and of short duration. Mean dive duration was 59.1 ± 63.5 s (SD). Maximum dive durations for the three pups were 5.8, 7.5, and 12 min. Maximum recorded depths were 12, 35, and 89 m. These depths represented the bottom in the area where each pup was situated. The average duration of haul-out sessions where nursing could take place was 6.3 ± 1.6 h, and the time between these sessions was 8.2 ± 3.2 h. The mean number of breathing holes found per pup was 8.7 ± 3.5. The large proportion of time spent in the water, the development of diving skills at an extremely young age, the use of multiple breathing holes, and the prolonged white-coat stage are all interpreted to be evolutionary responses to strong predation pressure, mainly from polar bears.

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