Distribution and Abundance of Seals in the Eastern Beaufort Sea

The objectives of this study were: (1) to design a statistically reliable method for surveying ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) that could be repeated and, (2) to obtain baseline information on the distribution, abundance, and general biology of ringed and bearded seals in relation to other mammals in the pack-ice ecosystem of the eastern Beaufort Sea.Because of the limitations encountered in aerial surveying during the period of optimum haul out, and the heterogeneous environment, we employed a stratified design incorporating a weighted linear regression model. Identical surveys, conducted from June 15 to 29, 1974 and from June 12 to 20, 1975, showed a significant decline in numbers of both seal species in 1975. This conclusion was supported by other independent observations. Observer bias in sighting and identifying the species of seals was tested for and rejected. Neither species was distributed randomly over the heterogeneous habitat but the degree of clumping was different. In general, bearded seals preferred shallower areas and ringed seals deeper ones.When the seal population declined, the reproductive rates of both species dropped markedly and young of the year virtually disappeared from the population. The reduction in numbers of seals stimulated a major change in reproductive rates of the polar bears (Ursus maritimus) and arctic foxes (Alopex lagopus) that depend upon them for food, and the bear and fox populations decreased in size.Some possible causes of the decline are discussed. This unprecedented variability in the stability of the marine ecosystem has serious management implications. Key words: census techniques, Phoca hispida, Erignathus barbatus, seals, interspecific relationships, Beaufort Sea

Download Full-text

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f96-346 ◽

1997 ◽

Vol 54 (4) ◽

pp. 914-921 ◽

Cited By ~ 12

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.

Download Full-text

Giardia duodenalis and Cryptosporidium Spp. in the Intestinal Contents of Ringed Seals (Phoca hispida) and Bearded Seals (Erignathus barbatus) in Nunavik, Quebec, Canada

Journal of Parasitology ◽

10.1645/ge-1485.1 ◽

2008 ◽

Vol 94 (5) ◽

pp. 1161-1163 ◽

Cited By ~ 41

Author(s):

Brent R. Dixon ◽

Lorna J. Parrington ◽

Monique Parenteau ◽

Daniel Leclair ◽

Mónica Santín ◽

...

Keyword(s):

Giardia Duodenalis ◽

Phoca Hispida ◽

Cryptosporidium Spp ◽

Ringed Seals ◽

Erignathus Barbatus ◽

Intestinal Contents ◽

Bearded Seals

Download Full-text

The Distribution and Abundance of Seals in the Canadian High Arctic, 1980–82

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f85-147 ◽

1985 ◽

Vol 42 (6) ◽

pp. 1189-1210 ◽

Cited By ~ 75

Author(s):

M. C. S. Kingsley ◽

I. Stirling ◽

W. Calvert

Keyword(s):

Deep Water ◽

High Arctic ◽

Phoca Hispida ◽

Canadian High Arctic ◽

Ringed Seals ◽

Preferred Habitat ◽

Erignathus Barbatus ◽

Sverdrup Basin ◽

Amundsen Gulf ◽

Bearded Seals

Surveys of hauled-out ringed seals (Phoca hispida) and bearded seals (Erignathus barbatus) were flown in 1980 and 1981 over Jones Sound, the Sverdrup Basin, the channels between the Parry Islands, the Parry Channel, Prince of Wales Strait, and northern Amundsen Gulf. Part of the survey was flown again in 1982. Ringed seals were most numerous in Barrow Strait and Wellington Channel, their density decreasing westward and northward. Their preferred habitat was annual ice, fast or cracking, of high cover; they avoided deep water. Bearded seals were seen in low numbers in early-opening areas, preferring floe or rotten ice of moderate or low cover over shallow water.

Download Full-text

Aspects of Predation of Seals by Polar Bears

Journal of the Fisheries Research Board of Canada ◽

10.1139/f77-169 ◽

1977 ◽

Vol 34 (8) ◽

pp. 1126-1129 ◽

Cited By ~ 156

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

Download Full-text

Direct and indirect effects of oil on ringed seals (Phoca hispida) of the Beaufort Sea

Deep Sea Research ◽

10.1016/0146-6291(77)90285-5 ◽

1977 ◽

Vol 24 (4) ◽

pp. 270

Keyword(s):

Indirect Effects ◽

Beaufort Sea ◽

Direct And Indirect Effects ◽

Phoca Hispida ◽

Ringed Seals

Download Full-text

Factors Affecting the Observed Densities of Ringed Seals, Phoca hispida, in the Alaskan Beaufort Sea, 1996-99

ARCTIC ◽

10.14430/arctic489 ◽

2004 ◽

Vol 57 (2) ◽

Cited By ~ 26

Author(s):

Kathryn J. Frost ◽

Lloyd F. Lowry ◽

Grey Pendleton ◽

Helen R. Nute

Keyword(s):

Beaufort Sea ◽

Phoca Hispida ◽

Factors Affecting ◽

Ringed Seals

Download Full-text

Variability in the Diet of Ringed Seals, Phoca hispida, in Alaska

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f80-270 ◽

1980 ◽

Vol 37 (12) ◽

pp. 2254-2261 ◽

Cited By ~ 79

Author(s):

Lloyd F. Lowry ◽

Kathryn J. Frost ◽

John J. Burns

Keyword(s):

Stomach Contents ◽

Late Summer ◽

Beaufort Sea ◽

Boundary Region ◽

Early Summer ◽

Phoca Hispida ◽

Arctic Cod ◽

Ringed Seals ◽

Saffron Cod ◽

Crangon Septemspinosa

Analysis of stomach contents of ringed seals (Phoca hispida) collected at eight locations along the Alaskan coast showed significant seasonal and regional differences in diet. During the spring–summer period saffron cod (Eleginus gracilis) was the most important food item in the nearshore zone of the northeastern Bering and southeastern Chukchi Seas. In that period shrimps (Pandalus spp., Eualus spp., Lebbeus polaris, and Crangon septemspinosa) were the major food in the northcentral Bering Sea, hyperiid amphipods (Parathemisto libellula) in the central Beaufort Sea and euphausiids (Thysanoessa spp.) in the boundary region (Barrow area) between the Chukchi and Beaufort seas. During late summer–early autumn hyperiid amphipods were important foods in the central Beaufort and the southeastern Chukchi. The autumn diet of seals in Norton Sound included mainly saffron cod During winter–early spring Arctic cod (Boreogadus saida) predominated the diet at all localities. During spring and early summer in the northeastern Bering and southeastern Chukchi seas the amount of saffron cod consumed was directly correlated with age. In the Beaufort Sea during autumn and winter Arctic cod were eaten in similar amounts by all age-classes. An analysis of the energy value and quantities of prey consumed indicates that prey species that occur in concentrations (Arctic and saffron cods, hyperiid amphipods, euphausiids and some shrimps) are of particular importance in the annual nutrition of ringed seals. These seals may be food limited in areas and during times when these kinds of prey are not available.Key words: food habits, Phoca hispida, ringed seals, Arctic cod, saffron cod, crustaceans, Alaska

Download Full-text

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

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-849 ◽

1995 ◽

Vol 52 (12) ◽

pp. 2594-2612 ◽

Cited By ~ 107

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.

Download Full-text

Distribution of ringed seals in the southeastern Beaufort Sea during late summer

Canadian Journal of Zoology ◽

10.1139/z92-127 ◽

1992 ◽

Vol 70 (5) ◽

pp. 891-900 ◽

Cited By ~ 41

Author(s):

Lois A. Harwood ◽

Ian Stirling

Keyword(s):

Relative Abundance ◽

Late Summer ◽

Beaufort Sea ◽

General Area ◽

Phoca Hispida ◽

Sea State ◽

Ringed Seals ◽

Aerial Surveys ◽

Early Fall

The distribution and relative abundance of ringed seals (Phoca hispida) in the southeastern Beaufort Sea were examined through systematic aerial surveys in August–September of 1982 and 1984–1986. All data analyzed were collected by the same observer when sea state was ≤ 2 on the Beaufort Scale and when there was no forward glare. In late summer and early fall of 1982, 1984, and 1986, ringed seals occurred singly and in groups, to an observed maximum of 21 seals. Groups of seals were clumped into large areas of aggregation which appeared to persist for several weeks. Densities in aggregation areas ranged from 121 to 326 seals/100 km2, approximately 6–13 times greater than regional mean densities. The geographic extent of aggregation areas (350–2800 km2) and the numbers (1 in 1984, 2 in 1982, 3 in 1986) and locations of aggregations varied among years. Ringed seals tended to aggregate most frequently and in greatest numbers in waters north of the Tuktoyaktuk Peninsula, in the general area where the Cape Bathurst polynya occurs in winter. The relative abundance of ringed seals varied among the years of the study, reaching a maximum in 1982 (42.20 seals/100 km2), declining through 1984 (14.73/100 km2) and 1985 (7.92/100 km2), and increasing again in 1986 (19.35/100 km2).

Download Full-text