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Estimating Age Ratios and Size of Pacific Walrus Herds on Coastal Haulouts using Video Imaging

Overview of attention for article published in PLOS ONE, July 2013
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About this Attention Score

  • In the top 25% of all research outputs scored by Altmetric
  • High Attention Score compared to outputs of the same age (89th percentile)
  • High Attention Score compared to outputs of the same age and source (82nd percentile)

Mentioned by

blogs
1 blog
twitter
7 tweeters
video
1 video uploader

Citations

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10 Dimensions

Readers on

mendeley
35 Mendeley
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Title
Estimating Age Ratios and Size of Pacific Walrus Herds on Coastal Haulouts using Video Imaging
Published in
PLOS ONE, July 2013
DOI 10.1371/journal.pone.0069806
Pubmed ID
Authors

Daniel H. Monson, Mark S. Udevitz, Chadwick V. Jay

Abstract

During Arctic summers, sea ice provides resting habitat for Pacific walruses as it drifts over foraging areas in the eastern Chukchi Sea. Climate-driven reductions in sea ice have recently created ice-free conditions in the Chukchi Sea by late summer causing walruses to rest at coastal haulouts along the Chukotka and Alaska coasts, which provides an opportunity to study walruses at relatively accessible locations. Walrus age can be determined from the ratio of tusk length to snout dimensions. We evaluated use of images obtained from a gyro-stabilized video system mounted on a helicopter flying at high altitudes (to avoid disturbance) to classify the sex and age of walruses hauled out on Alaska beaches in 2010-2011. We were able to classify 95% of randomly selected individuals to either an 8- or 3-category age class, and we found measurement-based age classifications were more repeatable than visual classifications when using images presenting the correct head profile. Herd density at coastal haulouts averaged 0.88 walruses/m(2) (std. err. = 0.02), herd size ranged from 8,300 to 19,400 (CV 0.03-0.06) and we documented ∼30,000 animals along ∼1 km of beach in 2011. Within the herds, dependent walruses (0-2 yr-olds) tended to be located closer to water, and this tendency became more pronounced as the herd spent more time on the beach. Therefore, unbiased estimation of herd age-ratios will require a sampling design that allows for spatial and temporal structuring. In addition, randomly sampling walruses available at the edge of the herd for other purposes (e.g., tagging, biopsying) will not sample walruses with an age structure representative of the herd. Sea ice losses are projected to continue, and population age structure data collected with aerial videography at coastal haulouts may provide demographic information vital to ongoing efforts to understand effects of climate change on this species.

Twitter Demographics

The data shown below were collected from the profiles of 7 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 35 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Germany 1 3%
Unknown 34 97%

Demographic breakdown

Readers by professional status Count As %
Student > Master 10 29%
Researcher 7 20%
Student > Bachelor 4 11%
Other 4 11%
Student > Ph. D. Student 3 9%
Other 2 6%
Unknown 5 14%
Readers by discipline Count As %
Agricultural and Biological Sciences 13 37%
Environmental Science 6 17%
Biochemistry, Genetics and Molecular Biology 2 6%
Social Sciences 2 6%
Nursing and Health Professions 2 6%
Other 4 11%
Unknown 6 17%

Attention Score in Context

This research output has an Altmetric Attention Score of 13. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 28 March 2021.
All research outputs
#1,882,014
of 18,950,555 outputs
Outputs from PLOS ONE
#25,085
of 171,259 outputs
Outputs of similar age
#18,025
of 170,838 outputs
Outputs of similar age from PLOS ONE
#682
of 3,919 outputs
Altmetric has tracked 18,950,555 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 90th percentile: it's in the top 10% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 171,259 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 13.9. This one has done well, scoring higher than 85% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 170,838 tracked outputs that were published within six weeks on either side of this one in any source. This one has done well, scoring higher than 89% of its contemporaries.
We're also able to compare this research output to 3,919 others from the same source and published within six weeks on either side of this one. This one has done well, scoring higher than 82% of its contemporaries.