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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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Autores principales: Shabangu, Fannie W., Yemane, Dawit, Stafford, Kathleen M., Ensor, Paul, Findlay, Ken P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5319791/
https://www.ncbi.nlm.nih.gov/pubmed/28222124
http://dx.doi.org/10.1371/journal.pone.0172705
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author Shabangu, Fannie W.
Yemane, Dawit
Stafford, Kathleen M.
Ensor, Paul
Findlay, Ken P.
author_facet Shabangu, Fannie W.
Yemane, Dawit
Stafford, Kathleen M.
Ensor, Paul
Findlay, Ken P.
author_sort Shabangu, Fannie W.
collection PubMed
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 conservation of this highly depleted species.
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spelling pubmed-53197912017-03-03 Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales Shabangu, Fannie W. Yemane, Dawit Stafford, Kathleen M. Ensor, Paul Findlay, Ken P. PLoS One Research Article 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 conservation of this highly depleted species. Public Library of Science 2017-02-21 /pmc/articles/PMC5319791/ /pubmed/28222124 http://dx.doi.org/10.1371/journal.pone.0172705 Text en © 2017 Shabangu et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Shabangu, Fannie W.
Yemane, Dawit
Stafford, Kathleen M.
Ensor, Paul
Findlay, Ken P.
Modelling the effects of environmental conditions on the acoustic occurrence and behaviour of Antarctic blue whales
title 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_short 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
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5319791/
https://www.ncbi.nlm.nih.gov/pubmed/28222124
http://dx.doi.org/10.1371/journal.pone.0172705
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