Effects of Whaling on the Structure of the Southern Ocean Food Web: Insights on the “Krill Surplus” from Ecosystem Modelling
The aim of this study was to examine the ecological plausibility of the “krill surplus” hypothesis and the effects of whaling on the Southern Ocean food web using mass-balance ecosystem modelling. The depletion trajectory and unexploited biomass of each rorqual population in the Antarctic was recons...
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ftpubmed:oai:pubmedcentral.nih.gov:4269391 2023-05-15T13:44:24+02:00 Effects of Whaling on the Structure of the Southern Ocean Food Web: Insights on the “Krill Surplus” from Ecosystem Modelling Surma, Szymon Pakhomov, Evgeny A. Pitcher, Tony J. 2014-12-17 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4269391 http://www.ncbi.nlm.nih.gov/pubmed/25517505 https://doi.org/10.1371/journal.pone.0114978 en eng Public Library of Science http://www.ncbi.nlm.nih.gov/pmc/articles/PMC http://www.ncbi.nlm.nih.gov/pubmed/25517505 http://dx.doi.org/10.1371/journal.pone.0114978 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. CC-BY Research Article Text 2014 ftpubmed https://doi.org/10.1371/journal.pone.0114978 2014-12-28T00:56:57Z The aim of this study was to examine the ecological plausibility of the “krill surplus” hypothesis and the effects of whaling on the Southern Ocean food web using mass-balance ecosystem modelling. The depletion trajectory and unexploited biomass of each rorqual population in the Antarctic was reconstructed using yearly catch records and a set of species-specific surplus production models. The resulting estimates of the unexploited biomass of Antarctic rorquals were used to construct an Ecopath model of the Southern Ocean food web existing in 1900. The rorqual depletion trajectory was then used in an Ecosim scenario to drive rorqual biomasses and examine the “krill surplus” phenomenon and whaling effects on the food web in the years 1900–2008. An additional suite of Ecosim scenarios reflecting several hypothetical trends in Southern Ocean primary productivity were employed to examine the effect of bottom-up forcing on the documented krill biomass trend. The output of the Ecosim scenarios indicated that while the “krill surplus” hypothesis is a plausible explanation of the biomass trends observed in some penguin and pinniped species in the mid-20th century, the excess krill biomass was most likely eliminated by a rapid decline in primary productivity in the years 1975–1995. Our findings suggest that changes in physical conditions in the Southern Ocean during this time period could have eliminated the ecological effects of rorqual depletion, although the mechanism responsible is currently unknown. Furthermore, a decline in iron bioavailability due to rorqual depletion may have contributed to the rapid decline in overall Southern Ocean productivity during the last quarter of the 20th century. The results of this study underscore the need for further research on historical changes in the roles of top-down and bottom-up forcing in structuring the Southern Ocean food web. Text Antarc* Antarctic Southern Ocean PubMed Central (PMC) Antarctic Rorqual ENVELOPE(-62.311,-62.311,-65.648,-65.648) Southern Ocean The Antarctic PLoS ONE 9 12 e114978 |
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PubMed Central (PMC) |
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English |
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Research Article |
spellingShingle |
Research Article Surma, Szymon Pakhomov, Evgeny A. Pitcher, Tony J. Effects of Whaling on the Structure of the Southern Ocean Food Web: Insights on the “Krill Surplus” from Ecosystem Modelling |
topic_facet |
Research Article |
description |
The aim of this study was to examine the ecological plausibility of the “krill surplus” hypothesis and the effects of whaling on the Southern Ocean food web using mass-balance ecosystem modelling. The depletion trajectory and unexploited biomass of each rorqual population in the Antarctic was reconstructed using yearly catch records and a set of species-specific surplus production models. The resulting estimates of the unexploited biomass of Antarctic rorquals were used to construct an Ecopath model of the Southern Ocean food web existing in 1900. The rorqual depletion trajectory was then used in an Ecosim scenario to drive rorqual biomasses and examine the “krill surplus” phenomenon and whaling effects on the food web in the years 1900–2008. An additional suite of Ecosim scenarios reflecting several hypothetical trends in Southern Ocean primary productivity were employed to examine the effect of bottom-up forcing on the documented krill biomass trend. The output of the Ecosim scenarios indicated that while the “krill surplus” hypothesis is a plausible explanation of the biomass trends observed in some penguin and pinniped species in the mid-20th century, the excess krill biomass was most likely eliminated by a rapid decline in primary productivity in the years 1975–1995. Our findings suggest that changes in physical conditions in the Southern Ocean during this time period could have eliminated the ecological effects of rorqual depletion, although the mechanism responsible is currently unknown. Furthermore, a decline in iron bioavailability due to rorqual depletion may have contributed to the rapid decline in overall Southern Ocean productivity during the last quarter of the 20th century. The results of this study underscore the need for further research on historical changes in the roles of top-down and bottom-up forcing in structuring the Southern Ocean food web. |
format |
Text |
author |
Surma, Szymon Pakhomov, Evgeny A. Pitcher, Tony J. |
author_facet |
Surma, Szymon Pakhomov, Evgeny A. Pitcher, Tony J. |
author_sort |
Surma, Szymon |
title |
Effects of Whaling on the Structure of the Southern Ocean Food Web: Insights on the “Krill Surplus” from Ecosystem Modelling |
title_short |
Effects of Whaling on the Structure of the Southern Ocean Food Web: Insights on the “Krill Surplus” from Ecosystem Modelling |
title_full |
Effects of Whaling on the Structure of the Southern Ocean Food Web: Insights on the “Krill Surplus” from Ecosystem Modelling |
title_fullStr |
Effects of Whaling on the Structure of the Southern Ocean Food Web: Insights on the “Krill Surplus” from Ecosystem Modelling |
title_full_unstemmed |
Effects of Whaling on the Structure of the Southern Ocean Food Web: Insights on the “Krill Surplus” from Ecosystem Modelling |
title_sort |
effects of whaling on the structure of the southern ocean food web: insights on the “krill surplus” from ecosystem modelling |
publisher |
Public Library of Science |
publishDate |
2014 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4269391 http://www.ncbi.nlm.nih.gov/pubmed/25517505 https://doi.org/10.1371/journal.pone.0114978 |
long_lat |
ENVELOPE(-62.311,-62.311,-65.648,-65.648) |
geographic |
Antarctic Rorqual Southern Ocean The Antarctic |
geographic_facet |
Antarctic Rorqual Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC http://www.ncbi.nlm.nih.gov/pubmed/25517505 http://dx.doi.org/10.1371/journal.pone.0114978 |
op_rights |
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. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1371/journal.pone.0114978 |
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PLoS ONE |
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9 |
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12 |
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e114978 |
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