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7 - Spatial and temporal variation in the diets of polar bears across the Canadian Arctic: indicators of changes in prey populations and environment

Published online by Cambridge University Press:  31 July 2009

C. J. Camphuysen
By
S. J. Iverson ,
I. Stirling  and
S. L. C. Lang
Edited by
I. L. Boyd  and
S. Wanless
C. J. Camphuysen
Affiliation:
Royal Netherlands Institute for Sea Research
S. J. Iverson
Affiliation:
Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1
I. Stirling
Affiliation:
Canadian Wildlife Service, Edmonton, Alberta, Canada T6H 3S5
S. L. C. Lang
Affiliation:
Dalhousie University, Halifax, Nova Scotia, Canada B3H 4J1
I. L. Boyd
Affiliation:
University of St Andrews, Scotland
S. Wanless
Affiliation:
NERC Centre for Ecology and Hydrology, UK
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Summary

Polar bears (Ursus maritimus) are broadly distributed in the Arctic and, as such, have the potential to provide information about changes in ecosystem structure and functioning over broad scales in time and space. Yet, because they are so wide-ranging and difficult to observe, there are few quantitative data on polar bear diets or on the ecological (e.g. climate change) and demographic factors that influence prey selection. We used quantitative fatty acid signature analysis of polar bear adipose tissue to estimate their diets in the 1980s/90s across three major regions of the Canadian Arctic: Davis Strait (n = 70), western Hudson Bay (n = 217) and the Beaufort Sea (n = 34), using a database of the major prey species in each region (n = 292). Although polar bears consumed ringed and bearded seals throughout their range, diets differed greatly among regions. Ringed seals accounted for ≥98% of diet in the Beaufort Sea. In western Hudson Bay, ringed seals accounted for about 80% of intake in the early 1990s, indicating the importance of foraging in ice-covered habitat. However, ringed seal consumption declined throughout the 1990s concurrent with progressively earlier ice breakup, while the proportions of bearded and harbour seals increased, suggesting reduced reliance on ice. Throughout Davis Strait, harp seals comprised 50% of bears' diets, consistent with the increase in the harp seal population in this region. Off southern Labrador near the whelping patch, harp seals accounted for 90% of diets.

Type
Chapter
Information
Top Predators in Marine Ecosystems
Their Role in Monitoring and Management
 , pp. 98 - 117
Publisher: Cambridge University Press
Print publication year: 2006

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References

Amstrup, S. C., Durner, G. M., Stirling, I., Lunn, N. & Messier, F. (2000). Movements and distribution of polar bears in the Beaufort Sea. Can. J. Zool., 78, 948–66.CrossRefGoogle Scholar
Bowen, W. D. (1997). Role of marine mammals in aquatic ecosystems. Mar. Ecol. Prog. Ser., 158, 267–74.CrossRefGoogle Scholar
Bowen, W. D. & Siniff, D. (1999). Distribution, population biology, and feeding ecology of marine mammals.: In Biology of Marine Mammals, eds. Reynolds, J. E. III & Rommel, S. A.. Washington, DC: Smithsonian Institution Press, pp. 423–84.Google Scholar
Budge, S. M., Iverson, S. J., Bowen, W. D. & Ackman, R. G. (2002). Among- and within-species variation in fatty acid signatures of marine fish and invertebrates on the Scotian Shelf, Georges Bank and southern Gulf of St. Lawrence. Can. J. Fish. Aquat. Sci., 59, 886–98.CrossRefGoogle Scholar
Cooper, M. H., Iverson, S. J. & Heras, H. (2005). Dynamics of blood chylomicron fatty acids in a marine carnivore: implications for lipid metabolism and quantitative estimation of predator diets. J. Comp. Physiol., 175, 133–45.CrossRefGoogle Scholar
Derocher, A. E., Andriashek, D. & Stirling, I. (1993). Terrestrial foraging by polar bears during the ice-free period in western Hudson Bay. Arctic, 46, 251–4.CrossRefGoogle Scholar
Derocher, A. E., Wiig, Ø. & Bangjord, G. (2000). Predation of Svalbard reindeer by polar bears. Polar Biol., 23, 675–8.CrossRefGoogle Scholar
DFO (Department of Fisheries and Oceans) (2000). Northwest Atlantic Harp Seals. DFO Science Stock Status Report E1-01. Dartmouth, Nova Scotia: Department of Fisheries and Oceans.
Estes, J. A. (1995). Top level carnivores and ecosystem effects: questions and approaches. In Linking Species and Ecosystems, eds. Jones, C. G. & Lawton, J. H.. Toronto, Canada: Chapman and Hall, pp. 151–8.CrossRefGoogle Scholar
Holst, M., Stirling, I. & Calvert, W. (1999). Age structure and reproductive rates of ringed seals (Phoca hispida) on the northwestern coast of Hudson Bay in 1991 and 1992. Mar. Mamm. Sci., 15, 1357–64.CrossRefGoogle Scholar
Iverson, S. J. (2002). Blubber. In Encyclopedia of Marine Mammals, eds. Perrin, W. F., Wursig, B. & Thewissen, H. G. M.. San Diego, CA: Academic Press, pp. 107–12.Google Scholar
Iverson, S. J., Arnould, J. P. Y. & Boyd, I. L. (1997). Milk fatty acid signatures indicate both major and minor shifts in diet of lactating Antarctic fur seals. Can. J. Zool., 75, 188–97.CrossRefGoogle Scholar
Iverson, S. J., Lang, S. L. C. & Cooper, M. (2001a). Comparison of the Bligh and Dyer and Folch methods for total lipid determination in a broad range of marine tissue. Lipids, 36, 1283–7.CrossRefGoogle Scholar
Iverson, S. J., MacDonald, J. & Smith, L. K. (2001b). Changes in diet of free-ranging black bears in years of contrasting food availability revealed through milk fatty acids. Can. J. Zool., 79, 2268–79.CrossRefGoogle Scholar
Iverson, S. J., Frost, K. J. & Lang, S. (2002). Fat content and fatty acid composition of forage fish and invertebrates in Prince William Sound, Alaska: factors contributing to among and within species variability. Mar. Ecol. Prog. Ser., 241, 161–81.CrossRefGoogle Scholar
Iverson, S. J., Field, C., Bowen, W. D. & Blanchard, W. (2004). Quantitative fatty acid signature analysis: a new method of estimating predator diets. Ecol. Monogr., 74, 211–35.CrossRefGoogle Scholar
Katona, S. & Whitehead, H. (1988). Are cetacea ecologically important?Oceanogr. Mar. Biol. Annu. Rev., 26, 553–68.Google Scholar
Layton, H. (1998). Development of digestive capabilities and improvement of diet utilization by mink pre- and post-weaning with emphasis on gastric lipase. M.Sc. thesis, Nova Scotia Agricultural College, Truro.
NOAA (National Oceanic and Atmospheric Administration) (1999). US Atlantic and Gulf of Mexico Marine Mammal Stock Assessments. NOAA Technical Memorandum NMFS-NE-153. Washington, DC: NOAA.
Paetkau, D., Amstrup, S. C., Born, E. W.et al. (1999). Genetic structure of the world's polar bear populations. Mol. Ecol., 8, 1571–85.CrossRefGoogle ScholarPubMed
Ramsay, M. A. & Stirling, I. (1988). Reproductive biology and ecology of female polar bears (Ursus maritimus). J. Zool. Lond., 214, 601–34.CrossRefGoogle Scholar
Smith, T. G. (1980). Polar bear predation of ringed and bearded seals in the land-fast sea ice habitat. Can. J. Zool., 58, 2201–9.CrossRefGoogle Scholar
Smith, T. G. & Sjare, B. (1990). Predation of belugas and narwhals by polar bears in nearshore areas of the Canadian High Arctic. Arctic, 43, 99–102.CrossRefGoogle Scholar
Stevens, J. (1986). Applied Multivariate Statistics for the Social Sciences. Mahwah, NJ: Lawrence Erlbaum Associates.Google Scholar
Stirling, I. (1974). Midsummer observations on the behavior of wild polar bears (Ursus maritimus). Can. J. Zool., 52, 1191–8.CrossRefGoogle Scholar
Stirling, I. (2002). Polar bears and seals in the Eastern Beaufort Sea and Amundsen Gulf: a synthesis of population trends and ecological relationships over three decades. Arctic, 55 (Suppl. 1), 59–76.CrossRefGoogle Scholar
Stirling, I. (2004). Reproductive rates of ringed seals and survival of pups in Northwestern Hudson Bay, Canada, 1991–2000. Polar Biol., 28, (DOI: 10.1007/s00300-004-0700-7).Google Scholar
Stirling, I. & Archibald, W. R. (1977). Aspects of predation of seals by polar bears. J. Fish. Res. Board Can., 34, 1126–9.CrossRefGoogle Scholar
Stirling, I. & Derocher, A. E. (1990). Factors affecting the evolution of the modern bears. Int. Conf. Bear Res. Managmt, 8, 189–205.Google Scholar
Stirling, I. & Derocher, A. E. (1993). Possible impacts of climatic warming on polar bears. Arctic, 46, 240–5.CrossRefGoogle Scholar
Stirling, I. & Øritsland, N. A. (1995). Relationships between estimates of ringed seal and polar bear populations in the Canadian Arctic. Can. J. Fish. Aquat. Sci., 52, 2594–612.CrossRefGoogle Scholar
Stirling, I., Jonkel, C., Smith, P., Robertson, R. & Cross, D. (1977). The Ecology of the Polar Bear (Ursus maritimus) Along the Western Coast of Hudson Bay. Canadian Wildlife Service Occasional Paper 33. Ontario, Canada: Canadian Wildlife Service.Google Scholar
Stirling, I., Lunn, N. J. & Iacozza, J. (1999). Long-term trends in the population ecology of polar bears in western Hudson Bay in relation to climatic change. Arctic, 52, 294–306.CrossRefGoogle Scholar
Taylor, M. & Lee, J. (1995). Distribution and abundance of Canadian polar bear populations: a management perspective. Arctic, 48, 147–54.CrossRefGoogle Scholar
Terborgh, J., Estes, J. A., Paquet, P. et al. (1999). The role of top carnivores in regulating terrestrial ecosystems. In Continental Conservation: Scientific Foundations of Regional Reserve Networks, eds. Soule, M. E. & Terborgh, J.. Washington, DC: Island Press, pp. 39–64.Google Scholar
Thiemann, G. W., Iverson, S. J. & Stirling, I.Seasonal, sexual, and anatomical variability in the adipose tissue composition of polar, bears (Ursus maritimus). J. Zool. Lond., in press.Google Scholar
Tynan, C. T. & DeMaster, D. P. (1997). Observations and predictions of Arctic climatic change: potential effects on marine mammals. Arctic, 50, 308–22.CrossRefGoogle Scholar

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