Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus)
Dissertation (Ph.D.) University of Alaska Fairbanks, 2009 This thesis describes investigations on bowhead whales (Balaena mysticetus) conducted over the past three decades, specifically on age, growth, morphology and energetics. The examined whales were harvested by Inupiat Eskimo whale hunters prim...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/9031 2023-05-15T15:16:37+02:00 Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus) George, John Craighead 2009 http://hdl.handle.net/11122/9031 unknown http://hdl.handle.net/11122/9031 Department of Biology and Wildlife Biological oceanography Dissertation phd 2009 ftunivalaska 2023-02-23T21:37:11Z Dissertation (Ph.D.) University of Alaska Fairbanks, 2009 This thesis describes investigations on bowhead whales (Balaena mysticetus) conducted over the past three decades, specifically on age, growth, morphology and energetics. The examined whales were harvested by Inupiat Eskimo whale hunters primarily in Barrow, Alaska. Bowheads are robust cetaceans reaching 19 m in length and inhabit the ice-covered waters of the circumpolar Arctic. They have the thickest blubber (? 35 cm) of any cetacean and the longest (>4 m) and most extensive baleen apparatus. Bowheads are ~4 m at birth and grow rapidly to ~8 m in their first year; they then experience a 2-3 year growth pause in both body length and mass. However the baleen continues to grow during this period. Sex differences are minimal but adult females tend to grow longer than males and males have larger pectoral limbs. Based on several lines of evidence, bowheads may routinely live to 150 years and thereby the longest-lived mammal. The recovery of 19 th century stone weapons from recently harvested whales confirms these age estimates. Age was estimated for 48 whales using the aspartic acid racemization technique, based on intrinsic changes of aspartic acid within the eye lens. The age at sexual maturity for bowheads occurs in the mid-20s. All harvested whales examined showed strong thermal gradients through their blubber (dermis and epidermis). A similar thermal gradient was evident through the muscle which is atypical of most terrestrial mammals. The deep body temperature averaged 33.8�C (SD=0.83, N = 28) which is lower than in other non-hibernating eutherian mammals. I did not see elevation of body temperatures in chased whales -- in fact these whales had slightly lower core temperatures. Resting metabolic rates for whales were estimated using a heat-loss technique. The thermal conductivity of the blubber for 5 whales averaged about 0.23 Wm-1K-1; similar to that of other whales and marine mammals. Heat flux rates varied highest to lowest as follows: palatal ... Doctoral or Postdoctoral Thesis Arctic Balaena mysticetus Barrow eskimo* Inupiat Alaska ice covered waters University of Alaska: ScholarWorks@UA Arctic Fairbanks |
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Open Polar |
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University of Alaska: ScholarWorks@UA |
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ftunivalaska |
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unknown |
topic |
Biological oceanography |
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Biological oceanography George, John Craighead Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus) |
topic_facet |
Biological oceanography |
description |
Dissertation (Ph.D.) University of Alaska Fairbanks, 2009 This thesis describes investigations on bowhead whales (Balaena mysticetus) conducted over the past three decades, specifically on age, growth, morphology and energetics. The examined whales were harvested by Inupiat Eskimo whale hunters primarily in Barrow, Alaska. Bowheads are robust cetaceans reaching 19 m in length and inhabit the ice-covered waters of the circumpolar Arctic. They have the thickest blubber (? 35 cm) of any cetacean and the longest (>4 m) and most extensive baleen apparatus. Bowheads are ~4 m at birth and grow rapidly to ~8 m in their first year; they then experience a 2-3 year growth pause in both body length and mass. However the baleen continues to grow during this period. Sex differences are minimal but adult females tend to grow longer than males and males have larger pectoral limbs. Based on several lines of evidence, bowheads may routinely live to 150 years and thereby the longest-lived mammal. The recovery of 19 th century stone weapons from recently harvested whales confirms these age estimates. Age was estimated for 48 whales using the aspartic acid racemization technique, based on intrinsic changes of aspartic acid within the eye lens. The age at sexual maturity for bowheads occurs in the mid-20s. All harvested whales examined showed strong thermal gradients through their blubber (dermis and epidermis). A similar thermal gradient was evident through the muscle which is atypical of most terrestrial mammals. The deep body temperature averaged 33.8�C (SD=0.83, N = 28) which is lower than in other non-hibernating eutherian mammals. I did not see elevation of body temperatures in chased whales -- in fact these whales had slightly lower core temperatures. Resting metabolic rates for whales were estimated using a heat-loss technique. The thermal conductivity of the blubber for 5 whales averaged about 0.23 Wm-1K-1; similar to that of other whales and marine mammals. Heat flux rates varied highest to lowest as follows: palatal ... |
format |
Doctoral or Postdoctoral Thesis |
author |
George, John Craighead |
author_facet |
George, John Craighead |
author_sort |
George, John Craighead |
title |
Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus) |
title_short |
Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus) |
title_full |
Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus) |
title_fullStr |
Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus) |
title_full_unstemmed |
Growth, Morphology And Energetics Of Bowhead Whales (Balaena Mysticetus) |
title_sort |
growth, morphology and energetics of bowhead whales (balaena mysticetus) |
publishDate |
2009 |
url |
http://hdl.handle.net/11122/9031 |
geographic |
Arctic Fairbanks |
geographic_facet |
Arctic Fairbanks |
genre |
Arctic Balaena mysticetus Barrow eskimo* Inupiat Alaska ice covered waters |
genre_facet |
Arctic Balaena mysticetus Barrow eskimo* Inupiat Alaska ice covered waters |
op_relation |
http://hdl.handle.net/11122/9031 Department of Biology and Wildlife |
_version_ |
1766346920989556736 |