Back to the future: Pacific walrus stress response and reproductive status in a changing Arctic
Thesis (M.S.) University of Alaska Fairbanks, 2016 The Pacific walrus (Odobenus rosmarus divergens) is an iconic Arctic marine mammal that Alaska Natives rely on as a subsistence, economic, and cultural resource. A decrease in critical sea ice habitat and uncertain population numbers have led to wal...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/6809 2023-05-15T15:02:17+02:00 Back to the future: Pacific walrus stress response and reproductive status in a changing Arctic Charapata, Patrick Maron Horstmann, Larissa Misarti, Nicole Wooller, Matthew 2016-08 http://hdl.handle.net/11122/6809 en_US eng http://hdl.handle.net/11122/6809 Marine Sciences and Limnology Program Thesis ms 2016 ftunivalaska 2023-02-23T21:36:43Z Thesis (M.S.) University of Alaska Fairbanks, 2016 The Pacific walrus (Odobenus rosmarus divergens) is an iconic Arctic marine mammal that Alaska Natives rely on as a subsistence, economic, and cultural resource. A decrease in critical sea ice habitat and uncertain population numbers have led to walruses being listed as a candidate for the Endangered Species Act. However, there is no clear understanding of how walruses might be affected by climate change. The first objective of this study was to describe how bone steroid hormone concentrations relate to commonly used blubber and serum steroid hormone concentrations (i.e., cortisol, estradiol, progesterone and testosterone), because steroid hormones have not been extracted from marine mammal bone until now. Bone, blubber, and serum were collected from individual adult walruses (n = 34) harvested by Native Alaskan subsistence hunters during 2014 and 2015. Complete turnover of cortical bone in a walrus skeleton was estimated as ~33 years, approximately the lifetime of a walrus. Results showed bone and blubber steroid hormone concentrations were similar (P = 0.96, 0.51, 0.27 for cortisol, estradiol, and progesterone (males only), respectively), but not testosterone (males and females, P = 0.003) nor progesterone in blubber of female walruses (P = 0.007). Progesterone concentrations in males were significantly correlated between bone and blubber (R² = 0.51, P < 0.001). Estradiol measured in bone had high interannual variability (P < 0.001), indicating a shorter reservoir time in cortical bone compared with other hormones in this study, possibly due to local production of estradiol in walrus bone. Overall, bone serves as a long-term reservoir of steroid hormone concentrations compared with circulating serum concentrations. Progesterone measured in blubber can be compared with bone progesterone, but local production of estradiol in bone should be taken into account when interpreting these concentrations in cortical bone. The second objective of this study was ... Thesis Arctic Climate change Odobenus rosmarus Sea ice Alaska walrus* University of Alaska: ScholarWorks@UA Arctic Fairbanks Pacific |
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University of Alaska: ScholarWorks@UA |
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ftunivalaska |
language |
English |
description |
Thesis (M.S.) University of Alaska Fairbanks, 2016 The Pacific walrus (Odobenus rosmarus divergens) is an iconic Arctic marine mammal that Alaska Natives rely on as a subsistence, economic, and cultural resource. A decrease in critical sea ice habitat and uncertain population numbers have led to walruses being listed as a candidate for the Endangered Species Act. However, there is no clear understanding of how walruses might be affected by climate change. The first objective of this study was to describe how bone steroid hormone concentrations relate to commonly used blubber and serum steroid hormone concentrations (i.e., cortisol, estradiol, progesterone and testosterone), because steroid hormones have not been extracted from marine mammal bone until now. Bone, blubber, and serum were collected from individual adult walruses (n = 34) harvested by Native Alaskan subsistence hunters during 2014 and 2015. Complete turnover of cortical bone in a walrus skeleton was estimated as ~33 years, approximately the lifetime of a walrus. Results showed bone and blubber steroid hormone concentrations were similar (P = 0.96, 0.51, 0.27 for cortisol, estradiol, and progesterone (males only), respectively), but not testosterone (males and females, P = 0.003) nor progesterone in blubber of female walruses (P = 0.007). Progesterone concentrations in males were significantly correlated between bone and blubber (R² = 0.51, P < 0.001). Estradiol measured in bone had high interannual variability (P < 0.001), indicating a shorter reservoir time in cortical bone compared with other hormones in this study, possibly due to local production of estradiol in walrus bone. Overall, bone serves as a long-term reservoir of steroid hormone concentrations compared with circulating serum concentrations. Progesterone measured in blubber can be compared with bone progesterone, but local production of estradiol in bone should be taken into account when interpreting these concentrations in cortical bone. The second objective of this study was ... |
author2 |
Horstmann, Larissa Misarti, Nicole Wooller, Matthew |
format |
Thesis |
author |
Charapata, Patrick Maron |
spellingShingle |
Charapata, Patrick Maron Back to the future: Pacific walrus stress response and reproductive status in a changing Arctic |
author_facet |
Charapata, Patrick Maron |
author_sort |
Charapata, Patrick Maron |
title |
Back to the future: Pacific walrus stress response and reproductive status in a changing Arctic |
title_short |
Back to the future: Pacific walrus stress response and reproductive status in a changing Arctic |
title_full |
Back to the future: Pacific walrus stress response and reproductive status in a changing Arctic |
title_fullStr |
Back to the future: Pacific walrus stress response and reproductive status in a changing Arctic |
title_full_unstemmed |
Back to the future: Pacific walrus stress response and reproductive status in a changing Arctic |
title_sort |
back to the future: pacific walrus stress response and reproductive status in a changing arctic |
publishDate |
2016 |
url |
http://hdl.handle.net/11122/6809 |
geographic |
Arctic Fairbanks Pacific |
geographic_facet |
Arctic Fairbanks Pacific |
genre |
Arctic Climate change Odobenus rosmarus Sea ice Alaska walrus* |
genre_facet |
Arctic Climate change Odobenus rosmarus Sea ice Alaska walrus* |
op_relation |
http://hdl.handle.net/11122/6809 Marine Sciences and Limnology Program |
_version_ |
1766334253852786688 |