Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales
Harvested to perilously low numbers by commercial whaling during the past century, the large scale response of Antarctic blue whales Balaenoptera musculus intermedia to environmental variability is poorly understood. This study uses acoustic data collected from 586 sonobuoys deployed in the austral...
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ftunivpretoria:oai:repository.up.ac.za:2263/61609 2023-05-15T14:05:19+02:00 Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales Shabangu, Fannie Welcome Yemane, Dawit Stafford, Kathleen M. Ensor, Paul Findlay, Kenneth Pierce 2017-02-21 http://hdl.handle.net/2263/61609 https://doi.org/10.1371/journal.pone.0172705 en eng Public Library of Science http://hdl.handle.net/2263/61609 1932-6203 doi:10.1371/journal.pone.0172705 © 2017 Shabangu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License. CC-BY Southern Ocean Environmental conditions Southern boundary of the Antarctic Circumpolar Current (SBACC) Antarctic blue whales (Balaenoptera musculus) Article 2017 ftunivpretoria https://doi.org/10.1371/journal.pone.0172705 2022-06-28T00:16:06Z Harvested to perilously low numbers by commercial whaling during the past century, the large scale response of Antarctic blue whales Balaenoptera musculus intermedia to environmental variability is poorly understood. This study uses acoustic data collected from 586 sonobuoys deployed in the austral summers of 1997 through 2009, south of 38°S, coupled with visual observations of blue whales during the IWC SOWER line-transect surveys. The characteristic Z-call and D-call of Antarctic blue whales were detected using an automated detection template and visual verification method. Using a random forest model, we showed the environmental preferences pattern, spatial occurrence and acoustic behaviour of Antarctic blue whales. Distance to the southern boundary of the Antarctic Circumpolar Current (SBACC), latitude and distance from the nearest Antarctic shores were the main geographic predictors of blue whale call occurrence. Satellite-derived sea surface height, sea surface temperature, and productivity (chlorophyll-a) were the most important environmental predictors of blue whale call occurrence. Call rates of D-calls were strongly predicted by the location of the SBACC, latitude and visually detected number of whales in an area while call rates of Z-call were predicted by the SBACC, latitude and longitude. Satellite-derived sea surface height, wind stress, wind direction, water depth, sea surface temperatures, chlorophyll-a and wind speed were important environmental predictors of blue whale call rates in the Southern Ocean. Blue whale call occurrence and call rates varied significantly in response to inter-annual and long term variability of those environmental predictors. Our results identify the response of Antarctic blue whales to inter-annual variability in environmental conditions and highlighted potential suitable habitats for this population. Such emerging knowledge about the acoustic behaviour, environmental and habitat preferences of Antarctic blue whales is important in improving the management and ... Article in Journal/Newspaper Antarc* Antarctic Balaenoptera musculus Blue whale Southern Ocean University of Pretoria: UPSpace Antarctic Southern Ocean The Antarctic Austral PLOS ONE 12 2 e0172705 |
institution |
Open Polar |
collection |
University of Pretoria: UPSpace |
op_collection_id |
ftunivpretoria |
language |
English |
topic |
Southern Ocean Environmental conditions Southern boundary of the Antarctic Circumpolar Current (SBACC) Antarctic blue whales (Balaenoptera musculus) |
spellingShingle |
Southern Ocean Environmental conditions Southern boundary of the Antarctic Circumpolar Current (SBACC) Antarctic blue whales (Balaenoptera musculus) Shabangu, Fannie Welcome Yemane, Dawit Stafford, Kathleen M. Ensor, Paul Findlay, Kenneth Pierce Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales |
topic_facet |
Southern Ocean Environmental conditions Southern boundary of the Antarctic Circumpolar Current (SBACC) Antarctic blue whales (Balaenoptera musculus) |
description |
Harvested to perilously low numbers by commercial whaling during the past century, the large scale response of Antarctic blue whales Balaenoptera musculus intermedia to environmental variability is poorly understood. This study uses acoustic data collected from 586 sonobuoys deployed in the austral summers of 1997 through 2009, south of 38°S, coupled with visual observations of blue whales during the IWC SOWER line-transect surveys. The characteristic Z-call and D-call of Antarctic blue whales were detected using an automated detection template and visual verification method. Using a random forest model, we showed the environmental preferences pattern, spatial occurrence and acoustic behaviour of Antarctic blue whales. Distance to the southern boundary of the Antarctic Circumpolar Current (SBACC), latitude and distance from the nearest Antarctic shores were the main geographic predictors of blue whale call occurrence. Satellite-derived sea surface height, sea surface temperature, and productivity (chlorophyll-a) were the most important environmental predictors of blue whale call occurrence. Call rates of D-calls were strongly predicted by the location of the SBACC, latitude and visually detected number of whales in an area while call rates of Z-call were predicted by the SBACC, latitude and longitude. Satellite-derived sea surface height, wind stress, wind direction, water depth, sea surface temperatures, chlorophyll-a and wind speed were important environmental predictors of blue whale call rates in the Southern Ocean. Blue whale call occurrence and call rates varied significantly in response to inter-annual and long term variability of those environmental predictors. Our results identify the response of Antarctic blue whales to inter-annual variability in environmental conditions and highlighted potential suitable habitats for this population. Such emerging knowledge about the acoustic behaviour, environmental and habitat preferences of Antarctic blue whales is important in improving the management and ... |
format |
Article in Journal/Newspaper |
author |
Shabangu, Fannie Welcome Yemane, Dawit Stafford, Kathleen M. Ensor, Paul Findlay, Kenneth Pierce |
author_facet |
Shabangu, Fannie Welcome Yemane, Dawit Stafford, Kathleen M. Ensor, Paul Findlay, Kenneth Pierce |
author_sort |
Shabangu, Fannie Welcome |
title |
Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales |
title_short |
Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales |
title_full |
Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales |
title_fullStr |
Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales |
title_full_unstemmed |
Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales |
title_sort |
modelling the effects of environmental conditions on the acoustic occurrence and behaviour of antarctic blue whales |
publisher |
Public Library of Science |
publishDate |
2017 |
url |
http://hdl.handle.net/2263/61609 https://doi.org/10.1371/journal.pone.0172705 |
geographic |
Antarctic Southern Ocean The Antarctic Austral |
geographic_facet |
Antarctic Southern Ocean The Antarctic Austral |
genre |
Antarc* Antarctic Balaenoptera musculus Blue whale Southern Ocean |
genre_facet |
Antarc* Antarctic Balaenoptera musculus Blue whale Southern Ocean |
op_relation |
http://hdl.handle.net/2263/61609 1932-6203 doi:10.1371/journal.pone.0172705 |
op_rights |
© 2017 Shabangu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1371/journal.pone.0172705 |
container_title |
PLOS ONE |
container_volume |
12 |
container_issue |
2 |
container_start_page |
e0172705 |
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1766277130343153664 |