Evaluating breeding habitat and populations of ringed seals Phoca hispida in Svalbard fjords

Polar Record ◽  
1991 ◽  
Vol 27 (162) ◽  
pp. 223-228 ◽  
Author(s):  
Christian Lydersen ◽  
Morten Ryg
Keyword(s):  
Condition Factor ◽  
Ice Cover ◽  
Ringed Seal ◽  
Stratified Sampling ◽  
Breeding Habitat ◽  
Phoca Hispida ◽  
Ringed Seals ◽  
Breeding Habitats ◽  
Breeding Condition ◽  
Areal Variation

AbstractIn Tempelfjorden and Sassenfjorden, Svalbard, 12 March to4 April 1990, a Siberian husky dog was used to detect ringed seal breathing holes in the ice, using random stratified sampling to sample 20% (40 km2) of the total area. The area was estimated to contain 997 ringed seal breathing holes, corresponding to 293 ringed seals. A maximum of 185 pups were born in the area. A breeding condition factor was constructed to enable comparisons of yearly and areal variation in ice cover and precipitation within ringed seal breeding habitats.

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.

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 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).

scholarly journals Stable ringed seal (Pusa hispida) demography despite significant habitat change in Svalbard, Norway

2021 ◽  
Vol 40 ◽  
Author(s):  
Magnus Andersen ◽  
Kit M. Kovacs ◽  
Christian Lydersen
Keyword(s):  
Life History ◽  
Sea Ice ◽  
Close Association ◽  
Ringed Seal ◽  
Breeding Habitat ◽  
Small Scale ◽  
Recent Period ◽  
Ringed Seals ◽  
Time Periods ◽  
Circumpolar Arctic

Ringed seals, which are small phocid seals, range across the circumpolar Arctic, and have evolved in close association with sea ice and depend on it for all aspects of their life history. This research study compares age structure, reproductive parameters, body size and condition during three time periods—1981–82 (n = 277), 2002–04 (n = 272) and 2012–18 (n = 212)—to study potential changes in demography in ringed seals in western Svalbard, Norway, an area that has undergone dramatic changes in sea-ice conditions during recent decades. Age distributions for the three time periods were similar, with the exception that the most recent period had a higher proportion of young animals. Age at sexual maturity for both sexes was similar for the two most recent periods, both being lower than in the 1980s. Ovulation rates did not vary significantly among the three periods (range 0.86–0.94). Pregnancy rates were only available for the most recent study period (0.71); this value falls within the range reported from other Arctic regions. Body length showed no clear temporal patterns; males were slightly longer in the most recent period, while females were slightly longer in the first period. Data from May in all periods suggest that body condition has not varied significantly through time. In conclusion, although the ringed seal breeding habitat in Svalbard has declined significantly in recent decades, demographic parameters appear to be largely unaffected. Life-history plasticity in combination with a small-scale regional variation in environmental conditions might explain the lack of changes in demography over time.

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.

Three-dimensional movements within individual dives by ringed seals (Phoca hispida)

2001 ◽  
Vol 79 (8) ◽  
pp. 1455-1464 ◽  
Author(s):  
Michael A Simpkins ◽  
Brendan P Kelly ◽  
Douglas Wartzok
Keyword(s):  
Travel Behavior ◽  
Three Dimensional ◽  
Ringed Seal ◽  
Travel Times ◽  
Phoca Hispida ◽  
Normal Distributions ◽  
Ringed Seals ◽  
Continuous Movement

We analyzed the three-dimensional movements within individual dives of five freely swimming ringed seals (Phoca hispida). We divided dives into a series of moves, each of which represented continuous movement in one direction, and evaluated several three-dimensional movement variables to distinguish between types of movement within dives. Horizontal directionality proved to be the most useful variable, and we distinguished convoluted and directional movements by fitting a mixture of two normal distributions to the observed horizontal-directionality values. Both convoluted and directional movements occurred within each phase of most dives, suggesting that ringed seals switched between behavioral modes within dive phases. Descent and ascent phases were not simply travel behavior, nor were bottom phases equivalent to patch time, complicating the formulation of optimal diving models for ringed seals. Most ringed seal dives appeared to consist of a series of patch times separated by travel times. Travel behavior accounted for the majority of dive times.

Uptake and Clearance of Petroleum Hydrocarbons in the Ringed Seal, Phoca hispida

1977 ◽  
Vol 34 (8) ◽  
pp. 1143-1147 ◽  
Author(s):  
F. Rainer Engelhardt ◽  
Joseph R. Geraci ◽  
Thomas G. Smith
Keyword(s):  
Crude Oil ◽  
Key Words ◽  
Plasma Levels ◽  
Petroleum Hydrocarbons ◽  
Ringed Seal ◽  
Phoca Hispida ◽  
Ringed Seals ◽  
Rapid Absorption ◽  
Body Tissues

Ringed seals, Phoca hispida, showed rapid absorption of hydrocarbons from Norman Wells crude oil into body tissues and fluids when exposed by both immersion and ingestion. Relatively low but significant levels were found in tissue, blood, and plasma. Levels in bile and urine were high, indicating these to be routes of excretion. Key words: petroleum, hydrocarbons, benzene, ringed seal, immersion, ingestion, uptake, clearance

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

1998 ◽  
Vol 1 ◽  
pp. 63 ◽  
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.

Oxygen stores and aerobic dive limit of ringed seals (Phoca hispida)

1992 ◽  
Vol 70 (3) ◽  
pp. 458-461 ◽  
Author(s):  
Christian Lydersen ◽  
Morten Skrede Ryg ◽  
Mike Osborne Hammill ◽  
Peter James O'Brien
Keyword(s):  
Ringed Seal ◽  
Composition Analysis ◽  
Phoca Hispida ◽  
Free Living ◽  
Weddell Seals ◽  
Lung Capacity ◽  
Ringed Seals ◽  
Aerobic Dive Limit ◽  
Oxygen Stores ◽  
Average Adult

In this paper we measured total lung capacity, myoglobin content of muscle tissue, and hemoglobin content of the blood of ringed seals (Phoca hispida). Based on this information and body composition analysis we estimated the total available oxygen stores of a diving average adult ringed seal (standard length 129 cm, body mass 73.7 kg) to be 4.5 L. The aerobic dive limit for a ringed seal of this size was estimated to be 8.9 min. Diving data from previous studies show that less than 4% of the dives of adult free-living ringed seals exceed this aerobic dive limit. Based on information from the literature on maximum breathhold capacity and observed maximum dive times of ringed and Weddell seals (Leptonychotes weddellii), the maximum breathhold capacity of adult ringed seals was suggested to be 26.1 min.

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