Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia.
We test the ability of Very High Resolution satellite (VHR) imagery to detect stranded whales using both manual and automated methods. We use the 2015 mass mortality event in the Gulf of Penas locality, central Patagonia, Chile, as an initial case study. This event was the largest known mass mortali...
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ftdoajarticles:oai:doaj.org/article:6dd5a105334147d7ac73b5d4d3b0387c 2023-05-15T15:36:16+02:00 Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. Peter T Fretwell Jennifer A Jackson Mauricio J Ulloa Encina Vreni Häussermann Maria J Perez Alvarez Carlos Olavarría Carolina S Gutstein 2019-01-01T00:00:00Z https://doi.org/10.1371/journal.pone.0222498 https://doaj.org/article/6dd5a105334147d7ac73b5d4d3b0387c EN eng Public Library of Science (PLoS) https://doi.org/10.1371/journal.pone.0222498 https://doaj.org/toc/1932-6203 1932-6203 doi:10.1371/journal.pone.0222498 https://doaj.org/article/6dd5a105334147d7ac73b5d4d3b0387c PLoS ONE, Vol 14, Iss 10, p e0222498 (2019) Medicine R Science Q article 2019 ftdoajarticles https://doi.org/10.1371/journal.pone.0222498 2022-12-31T05:56:46Z We test the ability of Very High Resolution satellite (VHR) imagery to detect stranded whales using both manual and automated methods. We use the 2015 mass mortality event in the Gulf of Penas locality, central Patagonia, Chile, as an initial case study. This event was the largest known mass mortality of baleen whales, with at least 343 whales, mainly sei whales (Balaenoptera borealis), documented as stranding. However, even with such a large number of whales, due to the remote location of the gulf the strandings went unrecorded for several weeks. Aerial and boat surveys of the area were conducted two to four months after the mortality event. In this study we use 50cm resolution WorldView2 imagery to identify and count strandings from two archival images acquired just after the stranding event and two months before the aerial and ground surveys, and to test manual and automated methods of detecting stranded whales. Our findings show that whales are easily detected manually in the images but due to the heterogeneous colouration of decomposing whales, spectral indices are unsuitable for automatic detection. Our satellite counts suggest that, at the time the satellite images were taken, more whales were stranded than recorded in the aerial survey, possibly due to the non-comprehensive coverage of the aerial survey or movement of the carcases between survey acquisition. With even higher resolution imagery now available, satellite imagery may be a cost effective alternative to aerial surveys for future assessment of the extent of mass whale stranding events, especially in remote and inaccessible areas. Article in Journal/Newspaper Balaenoptera borealis baleen whales Directory of Open Access Journals: DOAJ Articles Patagonia PLOS ONE 14 10 e0222498 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
language |
English |
topic |
Medicine R Science Q |
spellingShingle |
Medicine R Science Q Peter T Fretwell Jennifer A Jackson Mauricio J Ulloa Encina Vreni Häussermann Maria J Perez Alvarez Carlos Olavarría Carolina S Gutstein Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. |
topic_facet |
Medicine R Science Q |
description |
We test the ability of Very High Resolution satellite (VHR) imagery to detect stranded whales using both manual and automated methods. We use the 2015 mass mortality event in the Gulf of Penas locality, central Patagonia, Chile, as an initial case study. This event was the largest known mass mortality of baleen whales, with at least 343 whales, mainly sei whales (Balaenoptera borealis), documented as stranding. However, even with such a large number of whales, due to the remote location of the gulf the strandings went unrecorded for several weeks. Aerial and boat surveys of the area were conducted two to four months after the mortality event. In this study we use 50cm resolution WorldView2 imagery to identify and count strandings from two archival images acquired just after the stranding event and two months before the aerial and ground surveys, and to test manual and automated methods of detecting stranded whales. Our findings show that whales are easily detected manually in the images but due to the heterogeneous colouration of decomposing whales, spectral indices are unsuitable for automatic detection. Our satellite counts suggest that, at the time the satellite images were taken, more whales were stranded than recorded in the aerial survey, possibly due to the non-comprehensive coverage of the aerial survey or movement of the carcases between survey acquisition. With even higher resolution imagery now available, satellite imagery may be a cost effective alternative to aerial surveys for future assessment of the extent of mass whale stranding events, especially in remote and inaccessible areas. |
format |
Article in Journal/Newspaper |
author |
Peter T Fretwell Jennifer A Jackson Mauricio J Ulloa Encina Vreni Häussermann Maria J Perez Alvarez Carlos Olavarría Carolina S Gutstein |
author_facet |
Peter T Fretwell Jennifer A Jackson Mauricio J Ulloa Encina Vreni Häussermann Maria J Perez Alvarez Carlos Olavarría Carolina S Gutstein |
author_sort |
Peter T Fretwell |
title |
Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. |
title_short |
Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. |
title_full |
Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. |
title_fullStr |
Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. |
title_full_unstemmed |
Using remote sensing to detect whale strandings in remote areas: The case of sei whales mass mortality in Chilean Patagonia. |
title_sort |
using remote sensing to detect whale strandings in remote areas: the case of sei whales mass mortality in chilean patagonia. |
publisher |
Public Library of Science (PLoS) |
publishDate |
2019 |
url |
https://doi.org/10.1371/journal.pone.0222498 https://doaj.org/article/6dd5a105334147d7ac73b5d4d3b0387c |
geographic |
Patagonia |
geographic_facet |
Patagonia |
genre |
Balaenoptera borealis baleen whales |
genre_facet |
Balaenoptera borealis baleen whales |
op_source |
PLoS ONE, Vol 14, Iss 10, p e0222498 (2019) |
op_relation |
https://doi.org/10.1371/journal.pone.0222498 https://doaj.org/toc/1932-6203 1932-6203 doi:10.1371/journal.pone.0222498 https://doaj.org/article/6dd5a105334147d7ac73b5d4d3b0387c |
op_doi |
https://doi.org/10.1371/journal.pone.0222498 |
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PLOS ONE |
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14 |
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10 |
container_start_page |
e0222498 |
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