Variability in the Foraging Patterns of Polar Bears (Ursus Maritimus) in the Canadian High Arctic and Foxe Basin

Ongoing climate warming is projected to cause further declines in sea ice across the Arctic; as a result the foraging ecology of marine species will change. This thesis aimed to investigate the ecological patterns associated with polar bear diet selection. I characterized polar bear diet in the High Arctic, an area that supports a high density of bears and Foxe Basin, a subpopulation that has remained stable despite shifts in sea ice habitat. I used adipose tissue samples and quantitative fatty acid signature analysis to quantify diet composition. Lipid content was used as an indicator of body condition and decreased from fall to spring in bears when prey are less available. Diet estimates revealed spatial differences in polar bear foraging and identified the importance of locally and seasonally abundant prey. The ability of some individuals to alternate between prey species may help mitigate the effects of a declining sea ice habitat.