Field Projects: Polar Bears

Long-term Trends in Polar Bear Ecology in Relation to Climatic Change (map)

The western Hudson Bay Polar Bear population lives near the southern limit of the distribution of the species, where it is most vulnerable to changes in ice formation as a consequence of environmental or climatic fluctuations. Over the past 15-20 years, the condition and natality of this population of Polar Bears have been declining. These declines appear to be directly related to a trend towards the earlier breakup of sea ice in western Hudson Bay, due to warmer spring temperatures, which reduces the time that polar bears have access to seals. Although the declines in condition and natality have not yet led to a decline in the size of the population, it is clear that if the trends continue in the same direction, they will eventually have a detrimental effect on the ability of the population to sustain itself. The effects of long-term climatic change are not only restricted to Polar Bears in western Hudson Bay, but will be of obvious significance to polar bears throughout the circumpolar Arctic. The Hudson Bay population is the only one for which sufficient data currently exists to examine trends and determine effects. The purpose of this study is to capture an annual sample of Polar Bears, of all age and sex classes, to determine whether the declining trend in both cub production and body condition, which has occurred over the past 20 years, is continuing or has stabilized in order to provide timely data to assist in the ongoing, long-term conservation and management of polar bears in western Hudson Bay.

Duration: Ongoing

Partners: Manitoba Conservation, Northern Ecosystem Initiative (NEI), National Science and Engineering Research Council (NSERC), Nunavut Wildlife Management Board (NWMB), Parks Canada Agency (PC), WWF (Canada), WWF (AP)

Contact: Ian Stirling, Nick Lunn

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Polar Bear Male and Female Reproductive Success (map)

This study will describe the mating system of Polar Bears as determined from genetic evidence. Aspects of the mating system including the degree of inbreeding (inbreeding avoidance), frequency of mate choice, and the effective population size (proportion of adults breeding) will be examined. In addition, the study will estimate the mean and variance in male reproductive success, and examine individual reproductive success in relation to age and physical condition. Due to the long time span over which samples have been collected, estimates of lifetime reproductive success, reproductive lifespan, and the heritability of reproductive success will be determined. Genetic determination of parentage will also allow for a re-assessment of the frequency of natural adoption in polar bears, and the occurrence of multiple paternity within individual litters. The availability of a long-term dataset of field observations and tissue samples in conjunction with an efficient genetic methodology for parentage assessment will allow for a unique assessment of mating structure in a large, long lived mammal. The ability to examine mating structure will allow for a critical examination of the effect of current management practices, including the effects of the removal of males in a 2:1 ratio to females and the effects of removal of large (older) males from the population.

Duration: 2002 to 2005

Partners: NSERC, STAGE, U of A

Contact: Ian Stirling

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Movements and Population Dynamics of Polar Bears in the Beaufort Sea (map)

The purpose of this study is to more accurately define the population dynamics and movements of Polar Bears in the Beaufort Sea, and how those bears may be affected by proposed hydrocarbon development and shipping.

Duration: 2000 to 2007

Partners: Polar Continental Shelf Project (PCSP), RWED, USFWS, US Geological Service (USGS)

Contact: Ian Stirling

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Polar Bear Ecology and Behaviour (map)

This study analyzes the behaviour of undisturbed Polar Bears, evaluates the significance of polynyas to Polar Bears, and determines the relative importance of different habitat types to the bears.

Duration: Ongoing

Partners: Polar Continental Shelf Project (PCSP), U of A

Contact: Ian Stirling

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Ecology of Harbour Seals Summering in the Churchill River (map)

Industrial activities (including hydroelectric development) and climatic change have been identified as factors causing significant ecological change on a regional scale in Hudson and James bays. Recent unpublished data indicate that numbers of Harbour Seals may be increasing in western Hudson Bay, possibly in response to climatic warming, and that Harbour Seals are becoming more important in the diet of Polar Bears in western Hudson Bay. This suggests that this species may be an important indicator of ecological change accompanying climatic warming in the Arctic. The objective of this project is to study the year-round ecology of Harbour Seals that summer in the lower Churchill River. Satellite transmitters will be attached to locally-captured seals, then the movements throughout the year will be documented.

Duration: 2001 to 2004

Partners: Department of Fisheries and Oceans (DFO) (Mont Joli), Manitoba Hydro, NSERC, U of A

Contact: Ian Stirling

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Assessment of the Status of Ringed Seals in Western Hudson Bay (map)

Over the past 15-20 years, the condition and natality of Polar Bears in western Hudson Bay have been declining. These declines appear to be directly related to a trend towards the earlier breakup of sea ice in western Hudson Bay, due to warmer spring temperatures, which reduces the time that Polar Bears have access to seals. How Ringed Seals may be affected by long-term ecological or climatic fluctuations is unknown because there are few data on the biology of Ringed Seals anywhere in Hudson Bay that can be used to compare them to their conspecifics in other areas, evaluate hypotheses about their ecology, or aid in their conservation. The objective of this project is to collect baseline data on some biological parameters (e.g., population age structure, reproductive rates, and diet) for Ringed Seals in western Hudson Bay as part of a long-term study of the ecological relationships between Ringed Seals and Polar Bears.

Duration: Ongoing (inactive 2002)

Partners: NSERC, Nunavut Wildlife Management Board (NWMB)

Contact: Ian Stirling, Nick Lunn

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