Future sea ice conditions in Western Hudson Bay and consequences for polar bears in the 21st century

2013 ◽  
Vol 19 (9) ◽  
pp. 2675-2687 ◽  
Author(s):  
Laura Castro de la Guardia ◽  
Andrew E. Derocher ◽  
Paul G. Myers ◽  
Arjen D. Terwisscha van Scheltinga ◽  
Nick J. Lunn
Keyword(s):  
Sea Ice ◽  
21St Century ◽  
Hudson Bay ◽  
Polar Bears ◽  
Ice Conditions ◽  
Western Hudson Bay

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

2016 ◽  
Vol 2 (1) ◽  
pp. 15-32 ◽  
Author(s):  
M.E. Obbard ◽  
M.R.L. Cattet ◽  
E.J. Howe ◽  
K.R. Middel ◽  
E.J. Newton ◽  
...  
Keyword(s):  
Sea Ice ◽  
Body Condition ◽  
Survival Rates ◽  
Ursus Maritimus ◽  
Social Classes ◽  
The Arctic ◽  
Hudson Bay ◽  
Polar Bears ◽  
Western Hudson Bay ◽  
Break Up

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.

Effects of Earlier Sea Ice Breakup on Survival and Population Size of Polar Bears in Western Hudson Bay

2007 ◽  
Vol 71 (8) ◽  
pp. 2673-2683 ◽  
Author(s):  
ERIC V. REGEHR ◽  
NICHOLAS J. LUNN ◽  
STEVEN C. AMSTRUP ◽  
IAN STIRLING
Keyword(s):  
Sea Ice ◽  
Population Size ◽  
Hudson Bay ◽  
Polar Bears ◽  
Ice Breakup ◽  
Western Hudson Bay

scholarly journals The influence of sea ice dynamics on population energetics of Western Hudson Bay polar bears

Authorea ◽  
2020 ◽  
Author(s):  
Amy Johnson ◽  
Jody Reimer ◽  
Nicholas Lunn ◽  
Ian Stirling ◽  
David McGeachy ◽  
...  
Keyword(s):  
Sea Ice ◽  
Hudson Bay ◽  
Polar Bears ◽  
Ice Dynamics ◽  
Sea Ice Dynamics ◽  
Western Hudson Bay ◽  
Population Energetics

Decreasing sea ice conditions in western Hudson Bay and an increase in abundance of harbour seals (Phoca vitulina) in the Churchill River

Polar Biology ◽  
2018 ◽  
Vol 41 (6) ◽  
pp. 1187-1195 ◽  
Author(s):  
Katie R. N. Florko ◽  
Warren Bernhardt ◽  
C-Jae C. Breiter ◽  
Steven H. Ferguson ◽  
Meagan Hainstock ◽  
...  
Keyword(s):  
Sea Ice ◽  
Phoca Vitulina ◽  
Hudson Bay ◽  
Harbour Seals ◽  
Ice Conditions ◽  
Western Hudson Bay

Seasonal and annual movement patterns of polar bears on the sea ice of Hudson Bay

2006 ◽  
Vol 84 (9) ◽  
pp. 1281-1294 ◽  
Author(s):  
E.K. Parks ◽  
A.E. Derocher ◽  
N.J. Lunn
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Movement Patterns ◽  
Temporal Changes ◽  
Reproductive Status ◽  
Energy Output ◽  
Hudson Bay ◽  
Polar Bears ◽  
Western Hudson Bay ◽  
Break Up

Polar bears ( Ursus maritimus Phipps, 1774) move thousands of kilometres over sea ice searching for mates and hunting for seals, which are their primary prey. Recently, decreased sea ice extent and earlier ice break-up have been linked to shifts in seal distribution and abundance and to declines in polar bear condition and numbers in the western Hudson Bay polar bear population. We used geographic positioning system and satellite collars deployed between 1991 and 2004 to quantify movement patterns of adult female polar bears on the sea ice of Hudson Bay in relation to reproductive class and temporal variations in sea ice patterns. We tested whether reproductive status and season affected movement and whether temporal changes in movement were correlated with temporal changes in sea ice patterns in Hudson Bay. Movement patterns were not dependent on reproductive status but did change significantly with season. Annual distances moved and areas covered by bears in Hudson Bay have decreased since 1991, which suggests that measured declines in bear condition and numbers are due to reduced prey intake as opposed to increased energy output. These declines in bear movement are correlated with progressively earlier ice break-up in western Hudson Bay.

Distribution of polar bears (Ursus maritimus) during the ice-free period in western Hudson Bay

1990 ◽  
Vol 68 (7) ◽  
pp. 1395-1403 ◽  
Author(s):  
Andrew E. Derocher ◽  
Ian Stirling
Keyword(s):  
Energy Conservation ◽  
Sea Ice ◽  
Ursus Maritimus ◽  
North Coast ◽  
Hudson Bay ◽  
Polar Bears ◽  
Adult Males ◽  
The North ◽  
Western Hudson Bay ◽  
Age And Sex

The distribution and movements of polar bears (Ursus maritimus) during the ice-free period in western Hudson Bay were studied using mark and recapture and radiotelemetry locating of animals of known age and sex collected between 1966 and 1987. Polar bears segregated themselves by age, sex, and reproductive status. Adult males occupied coastal areas. Family groups and pregnant females occupied areas farther inland. Subadult females and males occupied similar habitats which overlapped with those of adult males. Avoidance of conspecifics, energy conservation, philopatry, denning habitat, and habitat selection appeared to influence observed patterns. A southward shift in the population was evident early in the ice-free period and was followed by a return movement northward during October and November. This may be due to ice-formation patterns which permit earlier access to the sea ice along the north coast and hunting habitat to the northeast. All bears moved less than bears on the sea ice, and movements were consistent with a strategy of energy conservation. Most bears appear to have travelled directly from the sea ice to the study area and remained until the sea ice reformed. Little exchange with adjacent populations and a high degree of philopatry were evident for all age and sex groups; this may be a function of the distribution of denning habitat, the winter distribution of sea ice habitat and seals, and the noncompetitive conditions that prevail during the ice-free period which make dispersal of limited benefit.

Heritability of body size in the polar bears of Western Hudson Bay

2018 ◽  
Vol 18 (4) ◽  
pp. 854-866 ◽  
Author(s):  
René M. Malenfant ◽  
Corey S. Davis ◽  
Evan S. Richardson ◽  
Nicholas J. Lunn ◽  
David W. Coltman
Keyword(s):  
Body Size ◽  
Hudson Bay ◽  
Polar Bears ◽  
Western Hudson Bay

scholarly journals Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water

2012 ◽  
Vol 90 (5) ◽  
pp. 663-676 ◽  
Author(s):  
A.M. Pagano ◽  
G.M. Durner ◽  
S.C. Amstrup ◽  
K.S. Simac ◽  
G.S. York
Keyword(s):  
Sea Ice ◽  
Adult Female ◽  
Open Water ◽  
Ursus Maritimus ◽  
Polar Bears ◽  
Long Distance ◽  
Gps Collars ◽  
Movement Data ◽  
Global Positioning ◽  
Ice Conditions

Polar bears ( Ursus maritimus Phipps, 1774) depend on sea ice for catching marine mammal prey. Recent sea-ice declines have been linked to reductions in body condition, survival, and population size. Reduced foraging opportunity is hypothesized to be the primary cause of sea-ice-linked declines, but the costs of travel through a deteriorated sea-ice environment also may be a factor. We used movement data from 52 adult female polar bears wearing Global Positioning System (GPS) collars, including some with dependent young, to document long-distance swimming (>50 km) by polar bears in the southern Beaufort and Chukchi seas. During 6 years (2004–2009), we identified 50 long-distance swims by 20 bears. Swim duration and distance ranged from 0.7 to 9.7 days (mean = 3.4 days) and 53.7 to 687.1 km (mean = 154.2 km), respectively. Frequency of swimming appeared to increase over the course of the study. We show that adult female polar bears and their cubs are capable of swimming long distances during periods when extensive areas of open water are present. However, long-distance swimming appears to have higher energetic demands than moving over sea ice. Our observations suggest long-distance swimming is a behavioral response to declining summer sea-ice conditions.

scholarly journals IcePAC – a probabilistic tool to study sea ice spatio-temporal dynamics: application to the Hudson Bay area

2019 ◽  
Vol 13 (2) ◽  
pp. 451-468 ◽  
Author(s):  
Charles Gignac ◽  
Monique Bernier ◽  
Karem Chokmani
Keyword(s):  
Sea Ice ◽  
Temporal Dynamics ◽  
Numerical Models ◽  
Temporal Distribution ◽  
Grid Cell ◽  
Hudson Bay ◽  
Sea Ice Concentration ◽  
Temporal Behaviour ◽  
Ice Conditions ◽  
Spatio Temporal

Abstract. A reliable knowledge and assessment of the sea ice conditions and their evolution in time is a priority for numerous decision makers in the domains of coastal and offshore management and engineering as well as in commercial navigation. As of today, countless research projects aimed at both modelling and mapping past, actual and future sea ice conditions were completed using sea ice numerical models, statistical models, educated guesses or remote sensing imagery. From this research, reliable information helping to understand sea ice evolution in space and in time is available to stakeholders. However, no research has, until present, assessed the evolution of sea ice cover with a frequency modelling approach, by identifying the underlying theoretical distribution describing the sea ice behaviour at a given point in space and time. This project suggests the development of a probabilistic tool, named IcePAC, based on frequency modelling of historical 1978–2015 passive microwave sea ice concentrations maps from the EUMETSAT OSI-409 product, to study the sea ice spatio-temporal behaviour in the waters of the Hudson Bay system in northeast Canada. Grid-cell-scale models are based on the generalized beta distribution and generated at a weekly temporal resolution. Results showed coherence with the Canadian Ice Service 1981–2010 Sea Ice Climatic Atlas average freeze-up and melt-out dates for numerous coastal communities in the study area and showed that it is possible to evaluate a range of plausible events, such as the shortest and longest probable ice-free season duration, for any given location in the simulation domain. Results obtained in this project pave the way towards various analyses on sea ice concentration spatio-temporal distribution patterns that would gain in terms of information content and value by relying on the kind of probabilistic information and simulation data available from the IcePAC tool.

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