1999/01/01 by Ian Stirling, Nicholas J. Lunn, John Iacozza · 4 citations
Earth and Planetary Sciences · Environmental Science · #Archaeology #Arctic #Arctic and Antarctic ice dynamics #Bay #Biology #Breakup #Climate change #Cryospheric studies and observations #Demography #Ecology #Environmental science #Geography #Geology #Marine animal studies overview #Oceanography #Period (music) #Polar night #Population
paper · pdf · doi:10.14430/arctic935
openalex publication_date 1999/01/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/10
From 1981 through 1998, the condition of adult male and female polar bears has declined significantly in western Hudson Bay, as have natality and the proportion of yearling cubs caught during the open water period that were independent at the time of capture. Over this same period, the breakup of the sea ice on western Hudson Bay has been occurring earlier. There was a significant positive relationship between the time of breakup and the condition of adult females (i.e., the earlier the breakup, the poorer the condition of the bears). The trend toward earlier breakup was also correlated with rising spring air temperatures over the study area from 1950 to 1990. We suggest that the proximate cause of the decline in physical and reproductive parameters of polar bears in western Hudson Bay over the last 19 years has been a trend toward earlier breakup, which has caused the bears to come ashore in progressively poorer condition. The ultimate factor responsible for the earlier breakup in western Hudson Bay appears to be a long-term warming trend in April-June atmospheric temperatures.