Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica
Understanding open-ocean predator-prey interactions is often hampered by a lack of information on prey fields at scales relevant to the behaviour of the predators. Hence, there is strong interest in identifying the biological and physical factors influencing the distribution and abundance of prey sp...
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ftunivtasecite:oai:ecite.utas.edu.au:134682 2023-05-15T13:55:18+02:00 Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica Bestley, S Cox, MJ Harcourt, RG Hindell, MA Jonsen, ID Nicol, S Peron, C Raymond, B Sumner, MD Weimerskirch, H Gales, NJ 2015 application/vnd.openxmlformats-officedocument.wordprocessingml.document http://www.imber.info/en/events/imber-working-groups-program-events/the-3rd-cliotop-symposium http://ecite.utas.edu.au/134682 en eng . http://ecite.utas.edu.au/134682/1/Bestley_S_theme6_CLIOTOPsym2015_submitted.docx Bestley, S and Cox, MJ and Harcourt, RG and Hindell, MA and Jonsen, ID and Nicol, S and Peron, C and Raymond, B and Sumner, MD and Weimerskirch, H and Gales, NJ, Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica, CLIOTOP 3rd Symposium 2015 Book of Abstracts, 14-18 September 2015, San Sebastian (2015) [Conference Extract] http://ecite.utas.edu.au/134682 Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) Conference Extract NonPeerReviewed 2015 ftunivtasecite 2019-12-13T22:32:18Z Understanding open-ocean predator-prey interactions is often hampered by a lack of information on prey fields at scales relevant to the behaviour of the predators. Hence, there is strong interest in identifying the biological and physical factors influencing the distribution and abundance of prey species, which may be of broad predictive use for conservation planning and evaluating effects of environmental change. This study focuses on a key Southern Ocean prey species, Antarctic krill, using acoustic observations of individual swarms from a large-scale survey off East Antarctica (BROKE-West, 2006). Two sets of statistical models are developed and evaluated that predict indices related to swarm densities: firstly using underway survey data for the explanatory variables, and secondly their satellite remotely-sensed analogues. While survey data are in situ and contemporaneous, remotely-sensed data is all that will be available for prediction and inference about prey distribution in most cases. Spatio-temporal confounding within these data requires some care, particularly with model selection, validation and estimation of uncertainties. Emergent patterns in fitted models show a strong lunar influence with higher night-time relative swarm densities amplified during the full moon. Complex environmental relationships indicate higher relative swarm densities in association with lower chlorophyll/fluorescence; in aged areas (longer time since ice melt) where rates of ice melt were higher; and in areas where bathymetric gradients were high but current gradients not extreme. Model performance was similar based on underway and remotely sensed predictors. Two applications are demonstrated (i) spatial prey-field prediction and (ii) spatio-temporal prediction along Antarctic predator satellite tracks drawn from independent studies. Outcomes include the prediction of prey field characteristics of practical use for predator studies, as well as identification of influential bio-physical variables of use in further modelling studies. Our methods are widely applicable to other high-latitude, krill-dependent, offshore ecosystems, and our findings should be relevant to similar efforts examining biophysical linkages elsewhere in the Southern Ocean. Conference Object Antarc* Antarctic Antarctic Krill Antarctica East Antarctica Southern Ocean eCite UTAS (University of Tasmania) Antarctic Southern Ocean East Antarctica |
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Open Polar |
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eCite UTAS (University of Tasmania) |
op_collection_id |
ftunivtasecite |
language |
English |
topic |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) |
spellingShingle |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) Bestley, S Cox, MJ Harcourt, RG Hindell, MA Jonsen, ID Nicol, S Peron, C Raymond, B Sumner, MD Weimerskirch, H Gales, NJ Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica |
topic_facet |
Biological Sciences Ecology Marine and Estuarine Ecology (incl. Marine Ichthyology) |
description |
Understanding open-ocean predator-prey interactions is often hampered by a lack of information on prey fields at scales relevant to the behaviour of the predators. Hence, there is strong interest in identifying the biological and physical factors influencing the distribution and abundance of prey species, which may be of broad predictive use for conservation planning and evaluating effects of environmental change. This study focuses on a key Southern Ocean prey species, Antarctic krill, using acoustic observations of individual swarms from a large-scale survey off East Antarctica (BROKE-West, 2006). Two sets of statistical models are developed and evaluated that predict indices related to swarm densities: firstly using underway survey data for the explanatory variables, and secondly their satellite remotely-sensed analogues. While survey data are in situ and contemporaneous, remotely-sensed data is all that will be available for prediction and inference about prey distribution in most cases. Spatio-temporal confounding within these data requires some care, particularly with model selection, validation and estimation of uncertainties. Emergent patterns in fitted models show a strong lunar influence with higher night-time relative swarm densities amplified during the full moon. Complex environmental relationships indicate higher relative swarm densities in association with lower chlorophyll/fluorescence; in aged areas (longer time since ice melt) where rates of ice melt were higher; and in areas where bathymetric gradients were high but current gradients not extreme. Model performance was similar based on underway and remotely sensed predictors. Two applications are demonstrated (i) spatial prey-field prediction and (ii) spatio-temporal prediction along Antarctic predator satellite tracks drawn from independent studies. Outcomes include the prediction of prey field characteristics of practical use for predator studies, as well as identification of influential bio-physical variables of use in further modelling studies. Our methods are widely applicable to other high-latitude, krill-dependent, offshore ecosystems, and our findings should be relevant to similar efforts examining biophysical linkages elsewhere in the Southern Ocean. |
format |
Conference Object |
author |
Bestley, S Cox, MJ Harcourt, RG Hindell, MA Jonsen, ID Nicol, S Peron, C Raymond, B Sumner, MD Weimerskirch, H Gales, NJ |
author_facet |
Bestley, S Cox, MJ Harcourt, RG Hindell, MA Jonsen, ID Nicol, S Peron, C Raymond, B Sumner, MD Weimerskirch, H Gales, NJ |
author_sort |
Bestley, S |
title |
Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica |
title_short |
Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica |
title_full |
Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica |
title_fullStr |
Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica |
title_full_unstemmed |
Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica |
title_sort |
prediction of krill swarm characteristics that drive a marine predator hotspot' region off east antarctica |
publisher |
. |
publishDate |
2015 |
url |
http://www.imber.info/en/events/imber-working-groups-program-events/the-3rd-cliotop-symposium http://ecite.utas.edu.au/134682 |
geographic |
Antarctic Southern Ocean East Antarctica |
geographic_facet |
Antarctic Southern Ocean East Antarctica |
genre |
Antarc* Antarctic Antarctic Krill Antarctica East Antarctica Southern Ocean |
genre_facet |
Antarc* Antarctic Antarctic Krill Antarctica East Antarctica Southern Ocean |
op_relation |
http://ecite.utas.edu.au/134682/1/Bestley_S_theme6_CLIOTOPsym2015_submitted.docx Bestley, S and Cox, MJ and Harcourt, RG and Hindell, MA and Jonsen, ID and Nicol, S and Peron, C and Raymond, B and Sumner, MD and Weimerskirch, H and Gales, NJ, Prediction of krill swarm characteristics that drive a marine predator hotspot' region off East Antarctica, CLIOTOP 3rd Symposium 2015 Book of Abstracts, 14-18 September 2015, San Sebastian (2015) [Conference Extract] http://ecite.utas.edu.au/134682 |
_version_ |
1766261706429825024 |