Physiological regulation of annual life history events in adult female Weddell seals
Dissertation (Ph.D.) University of Alaska Fairbanks, 2022 Predicting the impacts of environmental changes on animal populations requires a comprehensive understanding of the life history and physiological ecology of organisms in the wild, including the precise timing and regulation of annual biologi...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/13085 2023-05-15T14:02:28+02:00 Physiological regulation of annual life history events in adult female Weddell seals Kirkham, Amy Lorraine Burns, Jennifer Atkinson, Shannon Buck, C. Loren Tamone, Sherry Testa, J. Ward 2022-08 http://hdl.handle.net/11122/13085 en_US eng http://hdl.handle.net/11122/13085 Department of Fisheries Weddell seal Endocrinology Reproduction Somatotropin Antarctica Doctor of Philosophy in Fisheries Dissertation phd 2022 ftunivalaska 2023-02-23T21:38:02Z Dissertation (Ph.D.) University of Alaska Fairbanks, 2022 Predicting the impacts of environmental changes on animal populations requires a comprehensive understanding of the life history and physiological ecology of organisms in the wild, including the precise timing and regulation of annual biological events. In this dissertation, I assess how intrinsic factors including serum hormone concentrations and nutritional status relate to the critical annual events of reproduction, seasonal foraging, and pelage molt in an Antarctic marine predator, the Weddell seal (Leptonychotes weddellii). A large component of these assessments are comparisons between female Weddell seals that pupped in the current season (postpartum females) and females that have pupped in the past but did not give birth in the most recent pupping period (skip females). First, I examine how reproductive hormone profiles (serum progesterone, estrogen, prolactin, luteinizing hormone and follicle-stimulating hormone) vary between postpartum females and skip females across the austral summer. I found that skip females ovulated earlier than postpartum females and had higher serum estrogen and progesterone concentrations during early pregnancy. I also report a distinct midsummer decline in serum prolactin concentrations in both skip and postpartum seals. This decline may be due to seals becoming photorefractory at the time that the breeding period ends. Second, I characterize patterns in body mass changes and associated metabolic hormones and serum binding proteins (cortisol, growth hormone, insulin-like growth factor-1 (IGF-1), total and free thyroxine, total triiodothyronine, and IGF binding proteins 2 and 3) in Weddell seals across summer. I found that endocrine profiles of lactating seals reflected their depleted nutritional states, though their serum cortisol remained low. Postpartum females rapidly gained lean mass after weaning, which was likely supported by high serum growth hormone concentrations, while skip females lost body mass, probably ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctica Weddell Seal Weddell Seals Alaska University of Alaska: ScholarWorks@UA Antarctic Austral Fairbanks Weddell |
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Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
English |
topic |
Weddell seal Endocrinology Reproduction Somatotropin Antarctica Doctor of Philosophy in Fisheries |
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Weddell seal Endocrinology Reproduction Somatotropin Antarctica Doctor of Philosophy in Fisheries Kirkham, Amy Lorraine Physiological regulation of annual life history events in adult female Weddell seals |
topic_facet |
Weddell seal Endocrinology Reproduction Somatotropin Antarctica Doctor of Philosophy in Fisheries |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 2022 Predicting the impacts of environmental changes on animal populations requires a comprehensive understanding of the life history and physiological ecology of organisms in the wild, including the precise timing and regulation of annual biological events. In this dissertation, I assess how intrinsic factors including serum hormone concentrations and nutritional status relate to the critical annual events of reproduction, seasonal foraging, and pelage molt in an Antarctic marine predator, the Weddell seal (Leptonychotes weddellii). A large component of these assessments are comparisons between female Weddell seals that pupped in the current season (postpartum females) and females that have pupped in the past but did not give birth in the most recent pupping period (skip females). First, I examine how reproductive hormone profiles (serum progesterone, estrogen, prolactin, luteinizing hormone and follicle-stimulating hormone) vary between postpartum females and skip females across the austral summer. I found that skip females ovulated earlier than postpartum females and had higher serum estrogen and progesterone concentrations during early pregnancy. I also report a distinct midsummer decline in serum prolactin concentrations in both skip and postpartum seals. This decline may be due to seals becoming photorefractory at the time that the breeding period ends. Second, I characterize patterns in body mass changes and associated metabolic hormones and serum binding proteins (cortisol, growth hormone, insulin-like growth factor-1 (IGF-1), total and free thyroxine, total triiodothyronine, and IGF binding proteins 2 and 3) in Weddell seals across summer. I found that endocrine profiles of lactating seals reflected their depleted nutritional states, though their serum cortisol remained low. Postpartum females rapidly gained lean mass after weaning, which was likely supported by high serum growth hormone concentrations, while skip females lost body mass, probably ... |
author2 |
Burns, Jennifer Atkinson, Shannon Buck, C. Loren Tamone, Sherry Testa, J. Ward |
format |
Doctoral or Postdoctoral Thesis |
author |
Kirkham, Amy Lorraine |
author_facet |
Kirkham, Amy Lorraine |
author_sort |
Kirkham, Amy Lorraine |
title |
Physiological regulation of annual life history events in adult female Weddell seals |
title_short |
Physiological regulation of annual life history events in adult female Weddell seals |
title_full |
Physiological regulation of annual life history events in adult female Weddell seals |
title_fullStr |
Physiological regulation of annual life history events in adult female Weddell seals |
title_full_unstemmed |
Physiological regulation of annual life history events in adult female Weddell seals |
title_sort |
physiological regulation of annual life history events in adult female weddell seals |
publishDate |
2022 |
url |
http://hdl.handle.net/11122/13085 |
geographic |
Antarctic Austral Fairbanks Weddell |
geographic_facet |
Antarctic Austral Fairbanks Weddell |
genre |
Antarc* Antarctic Antarctica Weddell Seal Weddell Seals Alaska |
genre_facet |
Antarc* Antarctic Antarctica Weddell Seal Weddell Seals Alaska |
op_relation |
http://hdl.handle.net/11122/13085 Department of Fisheries |
_version_ |
1766272742247628800 |