Trends in body condition in polar bears ( Ursus maritimus ) from the Southern Hudson Bay subpopulation in relation to changes in sea ice

Arctic Science

article

M.E. Obbard¹  M.R.L. Cattet²  E.J. Howe¹  K.R. Middel¹  E.J. Newton¹  G.B. Kolenosky¹  K.F. Abraham¹  C.J. Greenwood¹ 

[1] Wildlife Research and Monitoring Section, Ontario Ministry of Natural Resources and Forestry, Trent University;Canadian Wildlife Health Cooperative, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive

关键词: body condition;    climate change;    Hudson Bay;    polar bear;    sea ice.;   

DOI  :  10.1139/as-2015-0027

学科分类：地球科学(综合)

来源: NRC Research Press

【 摘 要 】

Sea ice is declining over much of the Arctic. In Hudson Bay the ice melts completely each summer, and advances in break-up have resulted in longer ice-free seasons. Consequently, earlier break-up is implicated in declines in body condition, survival, and abundance of polar bears ( Ursus maritimus Phipps, 1774) in the Western Hudson Bay (WH) subpopulation. We hypothesised that similar patterns would be evident in the neighbouring Southern Hudson Bay (SH) subpopulation. We examined trends 1980–2012 in break-up and freeze-up dates within the entire SH management unit and within smaller coastal break-up and freeze-up zones. We examined trends in body condition for 900 bears captured during 1984–1986, 2000–2005, and 2007–2009 and hypothesised that body condition would be correlated with duration of sea ice. The ice-free season in SH increased by about 30 days from 1980 to 2012. Body condition declined in all age and sex classes, but the decline was less for cubs than for other social classes. If trends towards a longer ice-free season continue in the future, further declines in body condition and survival rates are likely, and ultimately declines in abundance will occur in the SH subpopulation.

【 授权许可】

CC BY