Seal body condition and atmospheric circulation patterns influence polar bear body condition, recruitment, and feeding ecology in the Chukchi Sea
Corresponding Author
Karyn D. Rode
Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA
Correspondence
Karyn D. Rode, Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA.
Email: [email protected]
Search for more papers by this authorEric V. Regehr
Polar Science Center, University of Washington, Seattle, WA, USA
Search for more papers by this authorJeffrey F. Bromaghin
Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA
Search for more papers by this authorRyan R. Wilson
Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
Search for more papers by this authorMichelle St. Martin
Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
Search for more papers by this authorJustin A. Crawford
Alaska Department of Fish and Game, Fairbanks, AK, USA
Search for more papers by this authorLori T. Quakenbush
Alaska Department of Fish and Game, Fairbanks, AK, USA
Search for more papers by this authorCorresponding Author
Karyn D. Rode
Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA
Correspondence
Karyn D. Rode, Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA.
Email: [email protected]
Search for more papers by this authorEric V. Regehr
Polar Science Center, University of Washington, Seattle, WA, USA
Search for more papers by this authorJeffrey F. Bromaghin
Alaska Science Center, U.S. Geological Survey, Anchorage, AK, USA
Search for more papers by this authorRyan R. Wilson
Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
Search for more papers by this authorMichelle St. Martin
Marine Mammals Management, U.S. Fish and Wildlife Service, Anchorage, AK, USA
Search for more papers by this authorJustin A. Crawford
Alaska Department of Fish and Game, Fairbanks, AK, USA
Search for more papers by this authorLori T. Quakenbush
Alaska Department of Fish and Game, Fairbanks, AK, USA
Search for more papers by this authorAbstract
Polar bears (Ursus maritimus) are experiencing loss of sea ice habitats used to access their marine mammal prey. Simultaneously, ocean warming is changing ecosystems that support marine mammal populations. The interactive effects of sea ice and prey are not well understood yet may explain spatial–temporal variation in the response of polar bears to sea ice loss. Here, we examined the potential combined effects of sea ice, seal body condition, and atmospheric circulation patterns on the body condition, recruitment, diet, and feeding probability of 469 polar bears captured in the Chukchi Sea, 2008–2017. The body condition of ringed seals (Pusa hispida), the primary prey of females and subadults, was related to dietary proportions of ringed seal, feeding probability, and the body condition of females and cubs. In contrast, adult males consumed more bearded seals (Erignathus barbatus) and exhibited better condition when bearded seal body condition was higher. The litter size, number of yearlings per adult female, and the condition of dependent young were higher following winters characterized by low Arctic Oscillation conditions, consistent with a growing number of studies. Body condition, recruitment, and feeding probability were either not associated or negatively associated with sea ice conditions, suggesting that, unlike some subpopulations, Chukchi Sea bears are not currently limited by sea ice availability. However, spring sea ice cover declined 2% per year during our study reaching levels not previously observed in the satellite record and resulting in the loss of polar bear hunting and seal pupping habitat. Our study suggests that the status of ice seal populations is likely an important factor that can either compound or mitigate the response of polar bears to sea ice loss over the short term. In the long term, neither polar bears nor their prey are likely robust to limitless loss of their sea ice habitat.
Open Research
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are openly available at: https://doi.org/10.5066/P9TVK3PX (polar bear body condition data), http://dx.doi.org/10.5066/F7SQ8XJC (serum urea and creatinine data), and https://dx.doi.org/10.5066/P92CRWOP (seal and polar bear tissue fatty acid data).
Supporting Information
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Citing Literature
June 2021
Pages 2684-2701