Intraspecific and temporal variability in the diet composition of female polar bears in a seasonal sea ice regime

• Main Authors: Sciullo, Luana, Thiemann, Greg, Lunn, Nicholas J., Ferguson, Steven H.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2017
• Subjects: Hudson; Hudson Bay; bearded seal; Beluga; Beluga whale; Beluga*; Delphinapterus leucas; Erignathus barbatus; harbour seal; Harp Seal; Odobenus rosmarus; Phoca vitulina; Pusa hispida; ringed seal; Sea ice; Ursus maritimus; walrus*
• Online Access: http://hdl.handle.net/1807/78621; http://www.nrcresearchpress.com/doi/abs/10.1139/AS-2017-0004

Predator foraging behaviour is influenced by intrinsic and extrinsic factors, including energetic requirements, resource availability, and habitat conditions.Polar bears (Ursus maritimus) are specialized predators of marine mammals adapted to a seasonal sea ice regime in much of their range.We used quantitative fatty acid signature analysis to estimate diet of 374 female polar bears from 2004 to 2014 in western Hudson Bay, Canada.Ringed seal (Pusa hispida) was the dominant prey, followed by bearded seal (Erignathus barbatus) and harbour seal (Phoca vitulina), with minimal consumption of beluga whale (Delphinapterus leucas), harp seal (Pagophilus groenlandica) and walrus (Odobenus rosmarus).Solitary adults and females with yearlings consumed more bearded seal than subadults or females with cubs-of-the-year (COY).Subadults may be too small or inexperienced to capture bearded seal and females with COY may avoid offshore pack ice where densities of bearded seal, and potentially infanticidal adult male polar bears, may be highest.A high dietary diversity in subadults and females with COY suggest less selective foraging and opportunistic scavenging.Bears consumed more harbour seal and less ringed seal in congruent years suggesting variable local prey availability.Date of sea ice breakup influenced diet of subadults and family groups more so than solitary females, suggesting differential sensitivity to sea ice conditions.Inter-annual variability in diet may be a consequence of differing responses of polar bears and prey species to sea ice conditions in Hudson Bay. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.