Polar bears in the southern Beaufort Sea II: Demography and population growth in relation to sea ice conditions

2007 ◽  
pp. 1-51 ◽  
Author(s):  
Christine M. Hunter ◽  
Hal Caswell ◽  
Michael C. Runge ◽  
Eric V. Regehr ◽  
Steven C. Amstrup ◽  
...  
Keyword(s):  
Sea Ice ◽  
Population Growth ◽  
Beaufort Sea ◽  
Polar Bears ◽  
Ice Conditions

Unusual Predation Attempts of Polar Bears on Ringed Seals in the Southern Beaufort Sea: Possible Significance of Changing Spring Ice Conditions

ARCTIC ◽  
2009 ◽  
Vol 61 (1) ◽  
pp. 14 ◽  
Author(s):  
Ian Stirling ◽  
Evan Richardson ◽  
Gregory W. Thiemann ◽  
Andrew E. Derocher
Keyword(s):  
Sea Ice ◽  
Polar Bear ◽  
Foraging Behaviour ◽  
Open Water ◽  
Beaufort Sea ◽  
Polar Bears ◽  
Ringed Seals ◽  
Decadal Scale ◽  
Underlying Causes ◽  
Ice Conditions

In April and May 2003 through 2006, unusually rough and rafted sea ice extended for several tens of kilometres offshore in the southeastern Beaufort Sea from about Atkinson Point to the Alaska border. Hunting success of polar bears (Ursus maritimus) seeking seals was low despite extensive searching for prey. It is unknown whether seals were less abundant in comparison to other years or less accessible because they maintained breathing holes below rafted ice rather than snowdrifts, or whether some other factor was involved. However, we found 13 sites where polar bears had clawed holes through rafted ice in attempts to capture ringed seals (Phoca hispida) in 2005 through 2006 and another site during an additional research project in 2007. Ice thickness at the 12 sites that we measured averaged 41 cm. These observations, along with cannibalized and starved polar bears found on the sea ice in the same general area in the springs of 2004 through 2006, suggest that during those years, polar bears in the southern Beaufort Sea were nutritionally stressed. Searches made farther north during the same period and using the same methods produced no similar observations near Banks Island or in Amundsen Gulf. A possible underlying ecological explanation is a decadal-scale downturn in seal populations. But a more likely explanation is major changes in the sea-ice and marine environment resulting from record amounts and duration of open water in the Beaufort and Chukchi seas, possibly influenced by climate warming. Because the underlying causes of observed changes in polar bear body condition and foraging behaviour are unknown, further study is warranted.

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 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 Increased Land Use by Chukchi Sea Polar Bears in Relation to Changing Sea Ice Conditions

PLoS ONE ◽  
2015 ◽  
Vol 10 (11) ◽  
pp. e0142213 ◽  
Author(s):  
Karyn D. Rode ◽  
Ryan R. Wilson ◽  
Eric V. Regehr ◽  
Michelle St. Martin ◽  
David C. Douglas ◽  
...  
Keyword(s):  
Land Use ◽  
Sea Ice ◽  
Chukchi Sea ◽  
Polar Bears ◽  
Ice Conditions

scholarly journals Foraminiferal assemblage changes over the last 15,000 years on the Mackenzie-Beaufort Sea Slope and Amundsen Gulf, Canada: Implications for past sea ice conditions

2009 ◽  
Vol 24 (2) ◽  
pp. n/a-n/a ◽  
Author(s):  
David B. Scott ◽  
Trecia Schell ◽  
Guillaume St-Onge ◽  
André Rochon ◽  
Steve Blasco
Keyword(s):  
Sea Ice ◽  
Beaufort Sea ◽  
Foraminiferal Assemblage ◽  
Ice Conditions ◽  
Amundsen Gulf

Variation in winter diet of southern Beaufort Sea polar bears inferred from stable isotope analysis

2007 ◽  
Vol 85 (5) ◽  
pp. 596-608 ◽  
Author(s):  
T.W. Bentzen ◽  
E.H. Follmann ◽  
S.C. Amstrup ◽  
G.S. York ◽  
M.J. Wooller ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Sea Ice ◽  
Trophic Level ◽  
Polar Bear ◽  
Isotope Analysis ◽  
Beaufort Sea ◽  
Polar Bears ◽  
Bowhead Whales ◽  
Lower Trophic Level ◽  
Winter Diet

Ringed seals ( Phoca hispida Schreber, 1775 = Pusa hispida (Schreber, 1775)) and bearded seals ( Erignathus barbatus (Erxleben, 1777)) represent the majority of the polar bear ( Ursus maritimus Phipps, 1774) annual diet. However, remains of lower trophic level bowhead whales ( Balaena mysticetus L., 1758) are available in the southern Beaufort Sea and their dietary contribution to polar bears has been unknown. We used stable isotope (13C/12C, δ13C, 15N/14N, and δ15N) analysis to determine the diet composition of polar bears sampled along Alaska’s Beaufort Sea coast in March and April 2003 and 2004. The mean δ15N values of polar bear blood cells were 19.5‰ (SD = 0.7‰) in 2003 and 19.9‰ (SD = 0.7‰) in 2004. Mixing models indicated bowhead whales composed 11%–26% (95% CI) of the diets of sampled polar bears in 2003, and 0%–14% (95% CI) in 2004. This suggests significant variability in the proportion of lower trophic level prey in polar bear diets among individuals and between years. Polar bears depend on sea ice for hunting seals, and the temporal and spatial availabilities of sea ice are projected to decline. Consumption of low trophic level foods documented here suggests bears may increasingly scavenge such foods in the future.

scholarly journals Characterizing sudden changes in Arctic sea ice drift and deformation on synoptic timescales

2016 ◽  
Author(s):  
Jennifer V. Lukovich ◽  
Cathleen A. Geiger ◽  
David G. Barber
Keyword(s):  
Sea Ice ◽  
Oil And Gas ◽  
Beaufort Sea ◽  
Arctic Sea Ice ◽  
Ice Drift ◽  
Shock Response ◽  
Near Shore ◽  
Sea Ice Drift ◽  
Ice Conditions ◽  
Ice Floes

Abstract. In this study, we develop a framework for the assessment of sudden changes in sea ice drift and associated deformation processes in response to atmospheric forcing and ice–coastal interactions, based on analysis of ice buoy triplet centroids and areas. Examined in particular is the spatiotemporal evolution in sea ice floes that are tracked with GPS beacons deployed in triplets in the southern Beaufort Sea at varying distances from the coastline in fall, 2009 – triplets A to D, with A (D) located closest to (furthest from) the coastline. This study illustrates the use of shock-response diagnostics to evaluate eight identified sudden changes or shock events on daily timescales. Results from this analysis show that shock events in the southern Beaufort Sea occur in at least one of two forms: (1) during a reversal in winds, or (2) sustained north/easterly winds, with response mechanisms governed by ice conditions and interactions with the coastline. Demonstrated also is the emergence of a shear-shock event (SSE) that results in reduced ice concentrations for triplets B, C, and D, one, three and five days following the SSE, respectively and loss of synchronicity in ice-atmosphere interactions. The tools developed in this study provide a unique characterization of sea ice dynamical processes in the southern Beaufort Sea, with implications for quantifying "shock-response" systems relevant for ice hazard assessments and forecasting applications required by oil and gas, marine transportation, and indigenous use of near shore Arctic areas.

scholarly journals Survival and breeding of polar bears in the southern Beaufort Sea in relation to sea ice

2010 ◽  
Vol 79 (1) ◽  
pp. 117-127 ◽  
Author(s):  
Eric V. Regehr ◽  
Christine M. Hunter ◽  
Hal Caswell ◽  
Steven C. Amstrup ◽  
Ian Stirling
Keyword(s):  
Sea Ice ◽  
Beaufort Sea ◽  
Polar Bears
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