Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna
Thesis (M.S.) University of Alaska Fairbanks, 2014 Stomach contents, stable isotopes, fatty acids, and more recently fecal DNA are commonly used to infer the diet of marine mammals. However, how complementary or contradictory these methods are, especially when considering individual diet variability...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/4651 2023-05-15T14:30:32+02:00 Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna Bryan, Anna Laura Hundertmark, Kris Horstmann-Dehn, Lara Hardy, Sarah Quakenbush, Lori 2014-08 http://hdl.handle.net/11122/4651 en_US eng http://hdl.handle.net/11122/4651 Department of Biology and Wildlife Thesis ms 2014 ftunivalaska 2023-02-23T21:36:16Z Thesis (M.S.) University of Alaska Fairbanks, 2014 Stomach contents, stable isotopes, fatty acids, and more recently fecal DNA are commonly used to infer the diet of marine mammals. However, how complementary or contradictory these methods are, especially when considering individual diet variability, remains poorly understood. This study assessed the differences in the dietary information resulting from stomach contents, stable isotopes, and fatty acids for adult bearded seals (Erignathus barbatus), and fishes identified from stomach contents and fecal DNA for bearded and ringed seals (Pusa hispida), harvested in Alaska for subsistence use. Stomach contents and fecal DNA provided information on recently consumed prey. In contrast, stable carbon and nitrogen isotopes of muscle and fatty acid profiles of blubber provided information on prey consumed and integrated over a longer time frame, but taxonomic resolution of prey was low. Overall, stomach contents provided the most dietary data, while fecal DNA delivered the least. Using denaturing gradient gel electrophoresis (DGGE) of 16S gene fragments, only 40% of the fecal samples (12 bearded and one ringed seal) produced detectable DNA suitable for reference gene amplification. Only three fish species could be positively identified in the diet of seals (Arctic cod, Boreogadus saida; shorthorn sculpin, Myoxocephalus scorpius; and an unknown snailfish species, Liparidae) when using fecal DNA. In a dietary comparison, and despite differences in dietary time frames, the relative occurrence (RO) of prey from stomach contents and the mean proportions of prey source groups from a Bayesian stable isotope mixing model (SIAR) were similar. The proportions of indicator fatty acids from full-thickness blubber, such as 16:4n-1, 20:5n-3, 20:4n-6, 20:1n-9, 22:1n-11, and the presence of non-methylene-interrupted fatty acids were similar to other fatty acid studies of bearded seals in Alaska, and suggest a benthic diet. Overall, the methods yielded different, but not necessarily ... Thesis Arctic cod Arctic Boreogadus saida Erignathus barbatus Pusa hispida ringed seal Alaska University of Alaska: ScholarWorks@UA Arctic Fairbanks |
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Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
English |
description |
Thesis (M.S.) University of Alaska Fairbanks, 2014 Stomach contents, stable isotopes, fatty acids, and more recently fecal DNA are commonly used to infer the diet of marine mammals. However, how complementary or contradictory these methods are, especially when considering individual diet variability, remains poorly understood. This study assessed the differences in the dietary information resulting from stomach contents, stable isotopes, and fatty acids for adult bearded seals (Erignathus barbatus), and fishes identified from stomach contents and fecal DNA for bearded and ringed seals (Pusa hispida), harvested in Alaska for subsistence use. Stomach contents and fecal DNA provided information on recently consumed prey. In contrast, stable carbon and nitrogen isotopes of muscle and fatty acid profiles of blubber provided information on prey consumed and integrated over a longer time frame, but taxonomic resolution of prey was low. Overall, stomach contents provided the most dietary data, while fecal DNA delivered the least. Using denaturing gradient gel electrophoresis (DGGE) of 16S gene fragments, only 40% of the fecal samples (12 bearded and one ringed seal) produced detectable DNA suitable for reference gene amplification. Only three fish species could be positively identified in the diet of seals (Arctic cod, Boreogadus saida; shorthorn sculpin, Myoxocephalus scorpius; and an unknown snailfish species, Liparidae) when using fecal DNA. In a dietary comparison, and despite differences in dietary time frames, the relative occurrence (RO) of prey from stomach contents and the mean proportions of prey source groups from a Bayesian stable isotope mixing model (SIAR) were similar. The proportions of indicator fatty acids from full-thickness blubber, such as 16:4n-1, 20:5n-3, 20:4n-6, 20:1n-9, 22:1n-11, and the presence of non-methylene-interrupted fatty acids were similar to other fatty acid studies of bearded seals in Alaska, and suggest a benthic diet. Overall, the methods yielded different, but not necessarily ... |
author2 |
Hundertmark, Kris Horstmann-Dehn, Lara Hardy, Sarah Quakenbush, Lori |
format |
Thesis |
author |
Bryan, Anna Laura |
spellingShingle |
Bryan, Anna Laura Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna |
author_facet |
Bryan, Anna Laura |
author_sort |
Bryan, Anna Laura |
title |
Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna |
title_short |
Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna |
title_full |
Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna |
title_fullStr |
Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna |
title_full_unstemmed |
Identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna |
title_sort |
identifying bearded and ringed seal diet - a comparison of stomach contents, stable isotopes, fatty acids, and fecal dna |
publishDate |
2014 |
url |
http://hdl.handle.net/11122/4651 |
geographic |
Arctic Fairbanks |
geographic_facet |
Arctic Fairbanks |
genre |
Arctic cod Arctic Boreogadus saida Erignathus barbatus Pusa hispida ringed seal Alaska |
genre_facet |
Arctic cod Arctic Boreogadus saida Erignathus barbatus Pusa hispida ringed seal Alaska |
op_relation |
http://hdl.handle.net/11122/4651 Department of Biology and Wildlife |
_version_ |
1766304364125749248 |