Contemporary diets of walruses in Bristol Bay, Alaska suggest temporal variability in benthic community structure
Background Pacific walruses (Odobenus rosmarus divergens) are a conspicuous and important component of the Bristol Bay ecosystem and human social systems, but very little is known about walrus ecology in this region, principally their feeding ecology. The present work provides contemporary data on t...
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ftdoajarticles:oai:doaj.org/article:f7e6e21667914656a910a2c884fa3134 2024-01-07T09:45:47+01:00 Contemporary diets of walruses in Bristol Bay, Alaska suggest temporal variability in benthic community structure John M. Maniscalco Alan M. Springer Katrina L. Counihan Tuula Hollmen Helen M. Aderman Moses Toyukak, Sr. 2020-03-01T00:00:00Z https://doi.org/10.7717/peerj.8735 https://doaj.org/article/f7e6e21667914656a910a2c884fa3134 EN eng PeerJ Inc. https://peerj.com/articles/8735.pdf https://peerj.com/articles/8735/ https://doaj.org/toc/2167-8359 doi:10.7717/peerj.8735 2167-8359 https://doaj.org/article/f7e6e21667914656a910a2c884fa3134 PeerJ, Vol 8, p e8735 (2020) Pacific walrus Odobenus rosmarus divergens Diet qPCR Bristol Bay Alaska Medicine R Biology (General) QH301-705.5 article 2020 ftdoajarticles https://doi.org/10.7717/peerj.8735 2023-12-10T01:51:32Z Background Pacific walruses (Odobenus rosmarus divergens) are a conspicuous and important component of the Bristol Bay ecosystem and human social systems, but very little is known about walrus ecology in this region, principally their feeding ecology. The present work provides contemporary data on the diets of walruses at four haulout locations throughout Bristol Bay between 2014 and 2018. Methods We analyzed scat and gastrointestinal tract samples from these animals using quantitative polymerase chain reaction to amplify prey DNA, which allowed for diet estimates based on frequencies of prey item occurrence and on the relative importance of dietary items as determined from DNA threshold cycle scores. Results Diets were highly diverse at all locations, but with some variation in composition that may be related to the time of year that samples were collected (summer vs. autumn), or to spatial variability in the distribution of prey. Overall, polychaetes and tunicates had the highest frequencies of occurrence and relative abundances in 2014–15, but a major change in diet appears to have occurred by 2017–18. While some sample sizes were small, diets in these later years contrasted sharply, with a greater prevalence of sea cucumbers and mollusks, and reduced importance of decapods and fishes compared to the earlier years. Prey identified in scat samples from one collection site also contrasted sharply with those reported from the same location in 1981. The apparent temporal shifts in walrus prey may represent a changing benthic ecosystem due to warming waters in recent decades. Article in Journal/Newspaper Odobenus rosmarus Alaska walrus* Directory of Open Access Journals: DOAJ Articles Pacific PeerJ 8 e8735 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Pacific walrus Odobenus rosmarus divergens Diet qPCR Bristol Bay Alaska Medicine R Biology (General) QH301-705.5 |
spellingShingle |
Pacific walrus Odobenus rosmarus divergens Diet qPCR Bristol Bay Alaska Medicine R Biology (General) QH301-705.5 John M. Maniscalco Alan M. Springer Katrina L. Counihan Tuula Hollmen Helen M. Aderman Moses Toyukak, Sr. Contemporary diets of walruses in Bristol Bay, Alaska suggest temporal variability in benthic community structure |
topic_facet |
Pacific walrus Odobenus rosmarus divergens Diet qPCR Bristol Bay Alaska Medicine R Biology (General) QH301-705.5 |
description |
Background Pacific walruses (Odobenus rosmarus divergens) are a conspicuous and important component of the Bristol Bay ecosystem and human social systems, but very little is known about walrus ecology in this region, principally their feeding ecology. The present work provides contemporary data on the diets of walruses at four haulout locations throughout Bristol Bay between 2014 and 2018. Methods We analyzed scat and gastrointestinal tract samples from these animals using quantitative polymerase chain reaction to amplify prey DNA, which allowed for diet estimates based on frequencies of prey item occurrence and on the relative importance of dietary items as determined from DNA threshold cycle scores. Results Diets were highly diverse at all locations, but with some variation in composition that may be related to the time of year that samples were collected (summer vs. autumn), or to spatial variability in the distribution of prey. Overall, polychaetes and tunicates had the highest frequencies of occurrence and relative abundances in 2014–15, but a major change in diet appears to have occurred by 2017–18. While some sample sizes were small, diets in these later years contrasted sharply, with a greater prevalence of sea cucumbers and mollusks, and reduced importance of decapods and fishes compared to the earlier years. Prey identified in scat samples from one collection site also contrasted sharply with those reported from the same location in 1981. The apparent temporal shifts in walrus prey may represent a changing benthic ecosystem due to warming waters in recent decades. |
format |
Article in Journal/Newspaper |
author |
John M. Maniscalco Alan M. Springer Katrina L. Counihan Tuula Hollmen Helen M. Aderman Moses Toyukak, Sr. |
author_facet |
John M. Maniscalco Alan M. Springer Katrina L. Counihan Tuula Hollmen Helen M. Aderman Moses Toyukak, Sr. |
author_sort |
John M. Maniscalco |
title |
Contemporary diets of walruses in Bristol Bay, Alaska suggest temporal variability in benthic community structure |
title_short |
Contemporary diets of walruses in Bristol Bay, Alaska suggest temporal variability in benthic community structure |
title_full |
Contemporary diets of walruses in Bristol Bay, Alaska suggest temporal variability in benthic community structure |
title_fullStr |
Contemporary diets of walruses in Bristol Bay, Alaska suggest temporal variability in benthic community structure |
title_full_unstemmed |
Contemporary diets of walruses in Bristol Bay, Alaska suggest temporal variability in benthic community structure |
title_sort |
contemporary diets of walruses in bristol bay, alaska suggest temporal variability in benthic community structure |
publisher |
PeerJ Inc. |
publishDate |
2020 |
url |
https://doi.org/10.7717/peerj.8735 https://doaj.org/article/f7e6e21667914656a910a2c884fa3134 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Odobenus rosmarus Alaska walrus* |
genre_facet |
Odobenus rosmarus Alaska walrus* |
op_source |
PeerJ, Vol 8, p e8735 (2020) |
op_relation |
https://peerj.com/articles/8735.pdf https://peerj.com/articles/8735/ https://doaj.org/toc/2167-8359 doi:10.7717/peerj.8735 2167-8359 https://doaj.org/article/f7e6e21667914656a910a2c884fa3134 |
op_doi |
https://doi.org/10.7717/peerj.8735 |
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PeerJ |
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8 |
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e8735 |
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