Regional walrus abundance estimate in the United States Chukchi Sea in autumn
Abstract Human activities (e.g., shipping, tourism, oil, gas development) have increased in the Chukchi Sea because of declining sea ice. The declining sea ice itself and these activities may affect Pacific walrus ( Odobenus rosmarus divergens ) abundance; however, previous walrus abundance estimate...
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crwiley:10.1002/jwmg.22256 2024-09-15T18:01:56+00:00 Regional walrus abundance estimate in the United States Chukchi Sea in autumn Fischbach, Anthony S. Taylor, Rebecca L. Jay, Chadwick V. U.S. Geological Survey 2022 http://dx.doi.org/10.1002/jwmg.22256 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jwmg.22256 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jwmg.22256 en eng Wiley http://creativecommons.org/licenses/by-nc-nd/4.0/ The Journal of Wildlife Management volume 86, issue 6 ISSN 0022-541X 1937-2817 journal-article 2022 crwiley https://doi.org/10.1002/jwmg.22256 2024-07-30T04:22:46Z Abstract Human activities (e.g., shipping, tourism, oil, gas development) have increased in the Chukchi Sea because of declining sea ice. The declining sea ice itself and these activities may affect Pacific walrus ( Odobenus rosmarus divergens ) abundance; however, previous walrus abundance estimates have been notably imprecise. When sea ice is absent from the eastern Chukchi Sea, walruses in waters of the United States usually rest together onshore at a single Alaska coastal haulout, where they can be surveyed more easily than when they rest on dispersed offshore ice floes. We estimated the number of walruses on land (herd size) at this haulout from 13 unoccupied aircraft system (UAS) surveys flown within a 10‐day period in each of 2018 and 2019. We estimated population size of walruses using the haulout over the course of the surveys by combining herd size data with data from satellite‐linked transmitters that indicated whether tagged walruses were in or out of water during each survey. Our estimates of the population size of walruses using the haulout during each year's survey period were similar to each other and more precise than historical walrus abundance estimates: posterior means (95% credibility intervals) were 166,000 (133,000–201,000) for 2018 and 189,000 (135,000–251,000) for 2019. Auxiliary observations support using these estimates to represent the size of the population using the eastern Chukchi Sea in autumn during the surveyed years. Our study site was the only substantial Chukchi Sea coastal haulout in the United States during the survey periods and study‐specific tracking data (consistent with known distribution and movement patterns) indicated tagged walruses remained in eastern Chukchi waters during the survey periods. In addition, the imagery, telemetry, and analytical methods developed for this study advance the prospect for precise range‐wide walrus population size estimates. Article in Journal/Newspaper Chukchi Chukchi Sea Odobenus rosmarus Sea ice Alaska walrus* Wiley Online Library The Journal of Wildlife Management 86 6 |
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Open Polar |
collection |
Wiley Online Library |
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crwiley |
language |
English |
description |
Abstract Human activities (e.g., shipping, tourism, oil, gas development) have increased in the Chukchi Sea because of declining sea ice. The declining sea ice itself and these activities may affect Pacific walrus ( Odobenus rosmarus divergens ) abundance; however, previous walrus abundance estimates have been notably imprecise. When sea ice is absent from the eastern Chukchi Sea, walruses in waters of the United States usually rest together onshore at a single Alaska coastal haulout, where they can be surveyed more easily than when they rest on dispersed offshore ice floes. We estimated the number of walruses on land (herd size) at this haulout from 13 unoccupied aircraft system (UAS) surveys flown within a 10‐day period in each of 2018 and 2019. We estimated population size of walruses using the haulout over the course of the surveys by combining herd size data with data from satellite‐linked transmitters that indicated whether tagged walruses were in or out of water during each survey. Our estimates of the population size of walruses using the haulout during each year's survey period were similar to each other and more precise than historical walrus abundance estimates: posterior means (95% credibility intervals) were 166,000 (133,000–201,000) for 2018 and 189,000 (135,000–251,000) for 2019. Auxiliary observations support using these estimates to represent the size of the population using the eastern Chukchi Sea in autumn during the surveyed years. Our study site was the only substantial Chukchi Sea coastal haulout in the United States during the survey periods and study‐specific tracking data (consistent with known distribution and movement patterns) indicated tagged walruses remained in eastern Chukchi waters during the survey periods. In addition, the imagery, telemetry, and analytical methods developed for this study advance the prospect for precise range‐wide walrus population size estimates. |
author2 |
U.S. Geological Survey |
format |
Article in Journal/Newspaper |
author |
Fischbach, Anthony S. Taylor, Rebecca L. Jay, Chadwick V. |
spellingShingle |
Fischbach, Anthony S. Taylor, Rebecca L. Jay, Chadwick V. Regional walrus abundance estimate in the United States Chukchi Sea in autumn |
author_facet |
Fischbach, Anthony S. Taylor, Rebecca L. Jay, Chadwick V. |
author_sort |
Fischbach, Anthony S. |
title |
Regional walrus abundance estimate in the United States Chukchi Sea in autumn |
title_short |
Regional walrus abundance estimate in the United States Chukchi Sea in autumn |
title_full |
Regional walrus abundance estimate in the United States Chukchi Sea in autumn |
title_fullStr |
Regional walrus abundance estimate in the United States Chukchi Sea in autumn |
title_full_unstemmed |
Regional walrus abundance estimate in the United States Chukchi Sea in autumn |
title_sort |
regional walrus abundance estimate in the united states chukchi sea in autumn |
publisher |
Wiley |
publishDate |
2022 |
url |
http://dx.doi.org/10.1002/jwmg.22256 https://onlinelibrary.wiley.com/doi/pdf/10.1002/jwmg.22256 https://onlinelibrary.wiley.com/doi/full-xml/10.1002/jwmg.22256 |
genre |
Chukchi Chukchi Sea Odobenus rosmarus Sea ice Alaska walrus* |
genre_facet |
Chukchi Chukchi Sea Odobenus rosmarus Sea ice Alaska walrus* |
op_source |
The Journal of Wildlife Management volume 86, issue 6 ISSN 0022-541X 1937-2817 |
op_rights |
http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1002/jwmg.22256 |
container_title |
The Journal of Wildlife Management |
container_volume |
86 |
container_issue |
6 |
_version_ |
1810439008596000768 |