scholarly journals Studies of the ringed seal (Phoca hispida Schreber 1775) in its breeding habitat in Kongsfjorden, Svalbard

1986 ◽  
Vol 4 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Christian Lydersen ◽  
Ian Gjertz
Keyword(s):  
Ringed Seal ◽  
Breeding Habitat ◽  
Phoca Hispida

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.

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.

Breeding habitat and lair structure of the ringed seal ( Phoca hispida ladogensis ) in northern Lake Ladoga in Russia

Polar Biology ◽  
2001 ◽  
Vol 24 (3) ◽  
pp. 171-174 ◽  
Author(s):  
Mervi Kunnasranta ◽  
Heikki Hyvärinen ◽  
Tero Sipilä ◽  
Nikolai Medvedev
Keyword(s):  
Ringed Seal ◽  
Breeding Habitat ◽  
Lake Ladoga ◽  
Phoca Hispida

The ringed seal (Phoca hispida) spring diet in northwestern Spitsbergen, Svalbard

1986 ◽  
Vol 4 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Ian Gjertz ◽  
Christian Lydersen
Keyword(s):  
Ringed Seal ◽  
Phoca Hispida

scholarly journals Mono-ortho and non-ortho substituted PCBs in Arctic ringed seal (Phoca hispida) from the Svalbard area: Analysis and determination of their toxic threat

Chemosphere ◽  
1993 ◽  
Vol 27 (1-3) ◽  
pp. 429-437 ◽  
Author(s):  
F.F. Daelemans ◽  
F. Mehlum ◽  
C. Lydersen ◽  
P.J.C. Schepens
Keyword(s):  
Ringed Seal ◽  
Phoca Hispida

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.

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.

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