Spatiotemporal use of lairs by ringed seals (Phoca hispida)

1990 ◽  
Vol 68 (12) ◽  
pp. 2503-2512 ◽  
Author(s):  
Brendan P. Kelly ◽  
Lori T. Quakenbush
Keyword(s):  
Early Spring ◽  
Late Spring ◽  
Phoca Hispida ◽  
Ringed Seals ◽  
Fast Ice ◽  
Males And Females

Thirteen ringed seals monitored by radiotelemetry in the shore-fast ice of the Beaufort and Chukchi seas were faithful to subnivean haulout sites from March to June. Each seal frequented as many as four lairs; the distances between lairs used by individual seals were as great as 3438 m. Mean distances between lairs used by individual males and females were 1997 and 634 m, respectively. Seals were not commonly seen resting on the ice outside of lairs until late May or June, but two radio-tagged male seals began basking on 15 April and 7 May, respectively. The proportion of time spent out of the water was 12.1% in March, 18.6% in April, 21.9% in May, and 42.9% in early June. From late March to June, males were out of the water during 13.1% of the monitored periods, and females were out of the water during 24.0% of those periods. Mean hours of haulout bouts were between 18:00 and 02:30 in early spring (except for a lactating female who hauled out most frequently at 11:00) and between 10:00 and 16:30 in late spring.

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 Status and biology of ringed seals (Phoca hispida) in Svalbard

1998 ◽  
Vol 1 ◽  
pp. 46 ◽  
Author(s):  
Christian Lydersen
Keyword(s):  
Body Mass ◽  
Dive Duration ◽  
Early Spring ◽  
Ringed Seal ◽  
The Arctic ◽  
Polar Cod ◽  
Net Energy ◽  
Adult Males ◽  
Ringed Seals ◽  
Males And Females

The ringed seal is the most abundant mammal in the Svalbard area. Annual pup production in this area is estimated to be 20,000. No systematic harvest records exist, but some few hundred seals are taken annually, mainly for dog food. The ringed seals in Svalbard are protected from hunting in the period 15 March - 15 April. Peak pupping season is the first week of April. New-born ringed seals weigh an average of 4.6 kg. They are nursed for about 39 days, and weaned at an average body mass of around 22 kg. During the period of maternal care pups consume a total of about 54 litres of milk, that is composed of approximately 38% fat and 10% protein. Asymptotic standard lengths and body masses for adult ringed seal males and females are 131.5 and 127.8 cm, and 52.6 and 59.9 kg,respectively. The maximum values recorded for lengths of males and females in Svalbard are 157 cm and 107 kg, respectively. There is marked seasonal variation in body mass in both sexes with the highest mass records being recorded in early spring before pupping occurs, and with minimum values in the summer after the breeding and moulting seasons. The observed variation in mass is mainly due to changing blubber thickness of the seals. Ringed seal males attain sexual maturity at the age of 5 - 7 years, while females reach maturity when they are 3-5 years of age. The oldest seal collected in Svalbard was aged 45. Ringed seals in the Svalbard area feed on a variety of prey organisms, the most important of which are polar cod (Boreogadus saida) and the crustaceans Parathemisto libellula, Thysanoessa inermis and Pandalus borealis. Ringed seal pups start diving during the nursing period while they are still white-coats, and spend about 50% of the time in thewater prior to weaning. They are capable of diving for up to 12min and dive to the bottom of the study areas (max. 89 m). Nursing females spend more than 80% of their time in the water. Maximum recorded dive duration for mothers was 21.2 min. In order to produce a weaned pup, the net energy expenditure for a ringed seal mother is 1,073 MJ. This energy value corresponds to the consumption of 185 kg of polar cod or 282 kg of P. libellula. The annual gross energy consumption for adult males and females is calculated to be 5,600 MJ and 7,300 MJ, respectively. The main predators of ringed seals in Svalbard are polar bears (Ursus maritimus) and Arctic foxes (Alopex lagopus). In addition, both glaucous gulls (Larus hyperboreus) and walruses (Odobenus rosmarus) are documented as predators of ringed seals in this area. Heavy predation pressure is probably the main factor explaining why pups of this species start diving at such a young age, why they have access to so many breathing holes (8.7 on average) and why they keep their white coat long after its thermoregulatory properties have vanished. Pollution levels in ringed seals from Svalbard are, generally speaking, similar to levels in other areas of the Arctic.

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.

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.

scholarly journals Abundance of ringed seals (Phoca hispida) in the Kong Oscars Fjord, Scoresby Sund and adjacent areas in eastern Greenland

1998 ◽  
Vol 1 ◽  
pp. 152 ◽  
Author(s):  
E W Born ◽  
J Teilmann ◽  
F Riget
Keyword(s):  
Phoca Hispida ◽  
Ringed Seals ◽  
Point Estimates ◽  
Visible Part ◽  
Main Emphasis ◽  
Fast Ice ◽  
The Mean ◽  
Marine Productivity ◽  
One Year ◽  
Survey Effort

With the purpose of determining the distribution and abundance of ringed seals (Phoca hispida) hauling out on the ice, systematic strip census aerial surveys were flown in the Kong Oscars Fjord, Scoresby Sund and adjacent areas (between approximately 70°N and 72°30'N in eastern Greenland) from 7 to 13 June 1984. The study area comprised approximately 18,500 km2 mainly covered with smooth one-year-old shore-fast ice. The survey effort was concentrated in the afternoon during the presumed peak haul-out period. Main emphasis was given to surveying the Kong Oscars Fjord/Davy Sund and the Scoresby Sund/Hurry Fjord areas which were surveyed twice. Average densities in various sub-areas varied between 0.3 and 2.9 seals/km2 and were similar tothose reported from other Arctic areas. No significant differences in densities were found between sets of surveys of the same sub-areas. The mean density (2.00 seals/km2, SD=0.22) in the Scoresby Sund area was significantly higher than that found in Kong Oscars Fjord (1.04 seals/km\ SD=0.15) probably reflecting a higher overall marine productivity in Scoresby Sund. The sum of the point estimates of the visible part of the population in the different sub-areas was 28,882 seals.

Ecology of the ringed seal, Phoca hispida, in its fast ice breeding habitat

1981 ◽  
Vol 59 (6) ◽  
pp. 966-981 ◽  
Author(s):  
Thomas G. Smith ◽  
Michael O. Hammill
Keyword(s):  
Behavioral Ecology ◽  
Population Regulation ◽  
Weddell Seal ◽  
Breeding Habitat ◽  
Baffin Island ◽  
Phoca Hispida ◽  
Fast Ice ◽  
Site Tenacity ◽  
Males And Females ◽  
The Antarctic

Studies of the behavioral ecology of seals hauled out on the sea ice at Popham Bay (64°17′ N, 65°30′ W) southeastern Baffin Island were conducted from 8 May to 6 June 1978 and 1 May to 20 June 1979. Similar densities and seasonal changes in numbers of hauled out seals were seen in both years. Seal numbers were positively correlated with date and negatively correlated with wind speed. While lying on the ice seals were vigilant and aggressive towards other seals, and females suckled their pups. Individuals were recognized by their different pelage marks. Both males and females showed site tenacity. One male, seen in 1978, was resighted in the study area in 1979. Our observations indicate that ringed seals are territorial and similar to the polygynous Weddell seal of the antarctic in their social organization. Population regulation appears to be affected by availability of suitable fast ice in which to maintain feeding and breeding habitat, with some adjustment of annual recruitment possibly in response to depleted food resources.

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. 

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.

Use of artificial subice air pockets by wild ringed seals (Phoca hispida)

1974 ◽  
Vol 52 (8) ◽  
pp. 1092-1093 ◽  
Author(s):  
Allen R. Milne
Keyword(s):  
Sea Ice ◽  
Air Bubbles ◽  
Phoca Hispida ◽  
Scuba Divers ◽  
Ringed Seals ◽  
Naturally Occurring ◽  
Drainage Channels ◽  
Fast Ice ◽  
Air Pockets

Ringed seals were observed to inhale exhaust air expelled by SCUBA divers who were diving under 1.9-m thick, 1-year-old fast ice in Lancaster Sound during mid-April, 1973, The underside of the sea ice was imperfectly flat so that some of the bubbles of exhaust air coalesced into large lenticular bubbles 1 to 3 cm in depth, and these, on occasions, were partially inhaled by seals. Between dives, separated in time by as little as 3 h, all the under-ice air bubbles, large and small, vanished. It is assumed that the buoyant air migrated upward into the sea ice by the progressive displacement of brine in drainage channels. Although the exhaust air was readily used by ringed seals, it is unlikely that naturally occurring air pockets can persist beneath 1 -year-old sea ice to enable seals to extend their under-ice travels.

Haul-out behaviour and densities of ringed seals (Phoca hispida) in the Barrow Strait area, N.W.T.

1979 ◽  
Vol 57 (10) ◽  
pp. 1985-1997 ◽  
Author(s):  
Kerwin J. Finley
Keyword(s):  
Wind Speed ◽  
Early Morning ◽  
Maximum Density ◽  
Stable Population ◽  
The Sun ◽  
High Wind ◽  
Phoca Hispida ◽  
High Wind Speed ◽  
Ringed Seals ◽  
Calm Weather

Numbers of ringed seals hauled out on the ice began to increase in early June. Numbers on the ice were highest from 0900 to 1500 hours Central Standard Time and lowest (average 40–50% of peak) in early morning. Seals commonly remained on the ice for several hours, and occasionally (during calm weather) for > 48 h. Numbers on the ice were reduced on windy days and possibly also on unusually warm, bright and calm days. Seals tended to face away from the wind (particularly with high wind speed) and oriented broadside to the sun. Seals usually occurred singly (60–70% of all groups) at their holes.Numbers of seals hauled out at Freemans Cove remained relatively constant during June (maximum density 4.86/km2), whereas at Aston Bay numbers increased dramatically to a maximum density of 10.44/km2 in late June. The increase was thought to be due to an influx of seals abandoning unstable ice. The density of seal holes at Freemans Cove (5.92/km2) was much higher than at Aston Bay (2.73/km2). The ratio of holes to the maximum numbers of seals (1.12:1) at Freemans Cove represents a first estimate of this relationship in an apparently stable population.

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