Blue whale body condition assessed over a 14-year period in the NE Pacific: annual variation and connection to measures of ocean productivity

Large marine mammals can serve as an indicator of the overall state of the environment due to their apex position in marine food webs and their functions as sentinels of change. Reductions in prey, driven by changes in environmental conditions can manifest in reduced fat stores that are visible on w...

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Published in:Frontiers in Marine Science
Main Authors: Wachtendonk, Rachel, Calambokidis, John, Flynn, Kiirsten
Format: Article in Journal/Newspaper
Language:English
Published: Frontiers Media 2022
Subjects:
Online Access:http://hdl.handle.net/10400.1/18470
https://doi.org/10.3389/fmars.2022.847032
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spelling ftunivalgarve:oai:sapientia.ualg.pt:10400.1/18470 2023-05-15T15:45:11+02:00 Blue whale body condition assessed over a 14-year period in the NE Pacific: annual variation and connection to measures of ocean productivity Wachtendonk, Rachel Calambokidis, John Flynn, Kiirsten 2022 http://hdl.handle.net/10400.1/18470 https://doi.org/10.3389/fmars.2022.847032 eng eng Frontiers Media 2296-7745 http://hdl.handle.net/10400.1/18470 doi:10.3389/fmars.2022.847032 openAccess http://creativecommons.org/licenses/by/4.0/ CC-BY Blue whalebody condition Environmental variability Photo-identification Marine heat wave article 2022 ftunivalgarve https://doi.org/10.3389/fmars.2022.847032 2022-11-09T01:01:58Z Large marine mammals can serve as an indicator of the overall state of the environment due to their apex position in marine food webs and their functions as sentinels of change. Reductions in prey, driven by changes in environmental conditions can manifest in reduced fat stores that are visible on whales. We developed a non-invasive technique using photographs of blue whales taken on the US west coast from 2005-2018 (n=3,660) and scored body condition based on visible undulations from the vertebral processes and body shape. We analyzed patterns in the body condition of whales across years and their relation to oceanographic conditions. Females with calves had significantly poorer body conditions and calves had significantly better body conditions compared to other adult whales (Chi-Square, x(2 =) 170.36, df=6, p<2.2e-16). Year was a significant factor in body condition (Chi-Square, x(2 =) 417.73, df=39, p<0.001). The highest proportion of whales in poor body condition was observed for 2015 (one of the only two years along with 2017 where >50% had poor body condition) coincides with the marine heat wave that affected the NE Pacific 2014-2016. A cumulative mixed model examining the relationship between body condition and environmental variables revealed that negative Pacific Decadal Oscillation and longer upwelling seasons correlated with better blue whale body condition, likely to be due to higher primary productivity and prey availability. This study indicates that with an adequate scoring method, photographs collected during boat based surveys can be used to effectively evaluate whale health in response to a changing ocean. info:eu-repo/semantics/publishedVersion Article in Journal/Newspaper Blue whale Universidade do Algarve: Sapienta Pacific Frontiers in Marine Science 9
institution Open Polar
collection Universidade do Algarve: Sapienta
op_collection_id ftunivalgarve
language English
topic Blue whalebody condition
Environmental variability
Photo-identification
Marine heat wave
spellingShingle Blue whalebody condition
Environmental variability
Photo-identification
Marine heat wave
Wachtendonk, Rachel
Calambokidis, John
Flynn, Kiirsten
Blue whale body condition assessed over a 14-year period in the NE Pacific: annual variation and connection to measures of ocean productivity
topic_facet Blue whalebody condition
Environmental variability
Photo-identification
Marine heat wave
description Large marine mammals can serve as an indicator of the overall state of the environment due to their apex position in marine food webs and their functions as sentinels of change. Reductions in prey, driven by changes in environmental conditions can manifest in reduced fat stores that are visible on whales. We developed a non-invasive technique using photographs of blue whales taken on the US west coast from 2005-2018 (n=3,660) and scored body condition based on visible undulations from the vertebral processes and body shape. We analyzed patterns in the body condition of whales across years and their relation to oceanographic conditions. Females with calves had significantly poorer body conditions and calves had significantly better body conditions compared to other adult whales (Chi-Square, x(2 =) 170.36, df=6, p<2.2e-16). Year was a significant factor in body condition (Chi-Square, x(2 =) 417.73, df=39, p<0.001). The highest proportion of whales in poor body condition was observed for 2015 (one of the only two years along with 2017 where >50% had poor body condition) coincides with the marine heat wave that affected the NE Pacific 2014-2016. A cumulative mixed model examining the relationship between body condition and environmental variables revealed that negative Pacific Decadal Oscillation and longer upwelling seasons correlated with better blue whale body condition, likely to be due to higher primary productivity and prey availability. This study indicates that with an adequate scoring method, photographs collected during boat based surveys can be used to effectively evaluate whale health in response to a changing ocean. info:eu-repo/semantics/publishedVersion
format Article in Journal/Newspaper
author Wachtendonk, Rachel
Calambokidis, John
Flynn, Kiirsten
author_facet Wachtendonk, Rachel
Calambokidis, John
Flynn, Kiirsten
author_sort Wachtendonk, Rachel
title Blue whale body condition assessed over a 14-year period in the NE Pacific: annual variation and connection to measures of ocean productivity
title_short Blue whale body condition assessed over a 14-year period in the NE Pacific: annual variation and connection to measures of ocean productivity
title_full Blue whale body condition assessed over a 14-year period in the NE Pacific: annual variation and connection to measures of ocean productivity
title_fullStr Blue whale body condition assessed over a 14-year period in the NE Pacific: annual variation and connection to measures of ocean productivity
title_full_unstemmed Blue whale body condition assessed over a 14-year period in the NE Pacific: annual variation and connection to measures of ocean productivity
title_sort blue whale body condition assessed over a 14-year period in the ne pacific: annual variation and connection to measures of ocean productivity
publisher Frontiers Media
publishDate 2022
url http://hdl.handle.net/10400.1/18470
https://doi.org/10.3389/fmars.2022.847032
geographic Pacific
geographic_facet Pacific
genre Blue whale
genre_facet Blue whale
op_relation 2296-7745
http://hdl.handle.net/10400.1/18470
doi:10.3389/fmars.2022.847032
op_rights openAccess
http://creativecommons.org/licenses/by/4.0/
op_rightsnorm CC-BY
op_doi https://doi.org/10.3389/fmars.2022.847032
container_title Frontiers in Marine Science
container_volume 9
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