Aspects of Predation of Seals by Polar Bears

Stirling, Ian; Archibald, W. Ralph

doi:10.1139/f77-169

Cited by 304 publications

(217 citation statements)

References 7 publications

Supporting

Mentioning

210

Contrasting

Order By: Relevance

“…The selection of breeding habitat by ringed seals has been considered in terms of ice and snow conditions (Chapskii 1940;McLaren 1958;Smith and Stirling 1975;Helle et al 1984;Kelly 2001;Kunnasranta et al 2001) and in terms of predation risk (Stirling 1977;Stirling and Archibald 1977;Smith 1976Smith , 1980Gjertz and Lydersen 1986;Lydersen and Smith 1989;Hammill and Smith 1991;Smith and Lydersen 1991;Furgal et al 1996;Kelly 1996). Little attention has been directed, however, to investigating the possible influence of prey densities or availability on selection of breeding habitat (Nazarenko 1967;Siegstad et al 1998;Holst et al 2001).…”

Section: Discussionmentioning

confidence: 99%

Seasonal home ranges and fidelity to breeding sites among ringed seals

et al. 2010

View full text Add to dashboard Cite

Population structure and patterns of habitat use among ringed seals (Phoca hispida) are poorly known, in part because seasonal movements have not been adequately documented. We monitored the movements of 98 ringed seals in the Beaufort and Chukchi seas between 1990 and 2006 using three forms of telemetry. In the winter-spring period (when the seals were occupying shorefast ice), we used radio and ultra-sonic tags to track movements above and below the ice, respectively. We used satellite-linked transmitters in summer and fall (when the seals ranged away from their winter sites) to track at-sea movements. In the shorefast ice habitat, the home ranges of 27 adult males ranged from \1 to 13.9 km 2 (median = 0.628) while the home ranges of 28 adult females ranged from \1 to 27.9 km 2 (median = 0.652). The 3-dimensional volumes used by 9 seals tracked acoustically under the ice averaged 0.07 (SD = 0.04) km 3 for subadults and adult males and 0.13 (SD = 0.04) km 3 for adult females. Three of the radio-tracked seals and 9 tracked by satellite ranged up to 1,800 km from their winter/spring home ranges in summer but returned to the same small (1-2 km 2 ) sites during the ice-bound months in the following year. The restricted movements of ringed seals during the ice-bound seasonincluding the breeding season-limits their foraging activities for most of the year and may minimize gene flow within the species.

show abstract

Section: Discussionmentioning

confidence: 99%

Seasonal home ranges and fidelity to breeding sites among ringed seals

et al. 2010

View full text Add to dashboard Cite

show abstract

“…The dates and locations of sampling and sex were recorded for each individual, and a vestigial premolar tooth (PM 1 ) was extracted for age determination. The age of the individuals was determined by counting annual growth layers in the cementum of the decalcified stained tooth according to methods described elsewhere (Stirling and Archibald, 1977;Calvert and Ramsay, 1998;Dietz et al, 2004).…”

Section: Field Samplingmentioning

confidence: 99%

Chlorinated hydrocarbon contaminants and metabolites in polar bears (Ursus maritimus) from Alaska, Canada, East Greenland, and Svalbard: 1996−2002

Verreault

Muir

Norstrom

et al. 2005

Science of The Total Environment

Self Cite

125

View full text Add to dashboard Cite

A suite of chlorinated hydrocarbon contaminants (CHCs) including organochlorine pesticides (OCPs) and by-products, polychlorinated biphenyls (PCBs), and methyl sulfone (MeSO 2 ) PCB and p,pV-dichlorodiphenyldichloroethylene ( p,pV-DDE) metabolites were determined in adipose tissue of 107 adult and sub-adult polar bears, almost exclusively females, sampled between 1996 and 2002 from populations spanning Arctic and Subarctic regions of Alaska, Canada, East Greenland, and Svalbard. The East Greenland and Svalbard populations of polar bears were distinguished by higher proportions of dichlorodiphenyldichloroethane (DDT)-related compounds, nonachlors, oxychlordane, and higher-chlorinated and persistent PCB congeners (hepta-to nona-chlorinated). Conversely, Alaska, the westernmost population of the North American Arctic, was characterized by higher proportions of relatively volatile compounds such as hexachlorocyclohexanes (HCHs) and pentachlorobenzene (PnCBz), lower-chlorinated PCB congeners (tri-to penta-chlorinated), and lower proportions of oxychlordane. Geometric mean (GM) with 95% confidence limits (CL) AHCH concentrations were highest in Alaska male polar bear fat samples (GM 593; CL 363À909 ng g À 1 lipid weight), ADDT concentration were highest in East Greenland female samples (GM 309; CL 249À490 ng g À 1 l.w.), and A 42 PCB (GM 5972; CL 4637À9129 ng g À 1 l.w.) and AMeSO 2 -PCB (GM 198; CL 162À279 ng g À 1 l.w.) concentrations were highest in female samples collected from Svalbard. The distribution of A-chlordanerelated compounds (ACHL), ACBz, mirex, and dieldrin was relatively uniform among the populations of polar bears investigated. The present 1996À2002 data of female polar bear fat samples was compared to spatial assessments of female polar bear fat samples collected between 1989 and 1993 from comparable populations. The two-point temporal comparisons showed a general decrease for age-adjusted mean concentrations of ACHL, p,pV-DDE, A 42 PCB, AMeSO 2 -PCB and 3-MeSO 2 -p,pV-DDE over a period of approximately 10 years. However, concentrations of dieldrin were comparatively unchanged. Comparisons of present 2001À2002 concentrations in fat of female polar bears from Western Hudson Bay showed great consistency with temporal trends (1991À1999) previously reported for the same region, i.e. the apparent non-decreasing trend of ACHL, h-HCH, AHCH and dieldrin, and the apparent declining trend for APCB. However, present concentrations of a-HCH and ACBz were elevated, and ADDT was notably lower in Western Hudson Bay samples compared to the last measurements in fat samples collected in 1999, which was not in accord with reported temporal trends for this region. As a result of their relatively high degree of contamination, East Greenland and Svalbard polar bears are at higher health risk of contaminant exposure among Arctic and Subarctic populations. In addition to continued biomonitoring, further research on health and population status is needed to evaluate the impact from chronic exposure of polar bear pop...

show abstract

“…Polar bears are predators that feed almost exclusively on seals Ž . Stirling and Archibald, 1977 . The bears' high and specific ability to metabolize many OCs, likely explains the lower concentrations of these compounds in these animals compared with white whales from the same area, except for the highly persistent PCBs which were five times higher in Ž .…”

Section: ( )mentioning

confidence: 99%

Concentrations and patterns of organochlorine contaminants in white whales (Delphinapterus leucas) from Svalbard, Norway

Andersen

Kovacs

Lydersen

et al. 2001

Science of The Total Environment

View full text Add to dashboard Cite

Ž. Blubber was collected from live-captured, adult male white whales Delphinapterus leucas from Svalbard, Norway, Ž . and analysed for levels and patterns of organochlorine OC contaminants. The OC compounds analysed were HCB, Ž . Ž dieldrin, ⌺HCH ␣-HCH, ␤-HCH and ␥-HCH , ⌺Chl heptachlor epoxide, oxychlordane, cis-chlordane, trans-non-. Ž . Ž . achlor, and cis-nonachlor , ⌺DDT ppЈ-DDT, ppЈ-DDE and ppЈ-DDD and ⌺PCB 27 PCB congeners . The major Ž . Ž . OC compounds detected in the blubber were ⌺PCB 5103 " 1874 ngrg l.w. and ⌺DDT 5108 " 1089 ngrg l.w. , Ž . which made up 70% of the ⌺OC. These compounds were followed in prevalence by ⌺Chl 2872 " 1177 ngrg l.w. , which contributed 20% of the ⌺OC burden. ⌺HCH, HCB and dieldrin were present, but at low concentrations. This OC pattern is typical of top predators in Arctic marine food chains. OC levels in white whales from Svalbard are lower than white whales from the St Lawrence River in Canada and are generally similar to values reported previously for other Arctic white whale stocks. Some geographic patterns in relative prevalence of various OC compounds appear to be quite consistent among various marine mammal species in the Arctic. PCB and DDT concentrations in Svalbard's white whales are below the levels that are thought to have negative effects on reproduction or the immune system. ᮊ

show abstract

Aspects of Predation of Seals by Polar Bears

Cited by 304 publications

References 7 publications

Seasonal home ranges and fidelity to breeding sites among ringed seals

Seasonal home ranges and fidelity to breeding sites among ringed seals

Chlorinated hydrocarbon contaminants and metabolites in polar bears (Ursus maritimus) from Alaska, Canada, East Greenland, and Svalbard: 1996−2002

Concentrations and patterns of organochlorine contaminants in white whales (Delphinapterus leucas) from Svalbard, Norway

Contact Info

Product

Resources

About