Southern elephant seal, samplers of marine resources distribution
Because of the remoteness and harsh meteorological conditions of the southern ocean, data sampling is more costly in this area. Use of electronic devices attached to marine predators (Bio-logging), such as southern elephant seals, has emerged as an interesting approach to cope with this problem. Fem...
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ftunivnantes:oai:HAL:tel-01906055v1 2023-05-15T16:05:24+02:00 Southern elephant seal, samplers of marine resources distribution L’éléphant de mer austral, bio-échantillonneur de la distribution des ressources marines Le Bras, Yves Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS) Université de La Rochelle Christophe Guinet 2017-03-29 https://theses.hal.science/tel-01906055 https://theses.hal.science/tel-01906055/document https://theses.hal.science/tel-01906055/file/thesis_Yves_LE_BRAS_final2.pdf fr fre HAL CCSD NNT: 2017LAROS036 tel-01906055 https://theses.hal.science/tel-01906055 https://theses.hal.science/tel-01906055/document https://theses.hal.science/tel-01906055/file/thesis_Yves_LE_BRAS_final2.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01906055 Sciences agricoles. Université de La Rochelle, 2017. Français. ⟨NNT : 2017LAROS036⟩ Southern elephant seals Bio-logging Myctophids Southern ocean Fine scale Diving behaviour Predator-prey interactions Eléphant de mer austral Myctophidés Océan austral Fine échelle Comportement de plongée Interactions prédateur-proies [SDV.SA]Life Sciences [q-bio]/Agricultural sciences info:eu-repo/semantics/doctoralThesis Theses 2017 ftunivnantes 2023-01-04T00:03:37Z Because of the remoteness and harsh meteorological conditions of the southern ocean, data sampling is more costly in this area. Use of electronic devices attached to marine predators (Bio-logging), such as southern elephant seals, has emerged as an interesting approach to cope with this problem. Female southern elephant seals primarily feed on small bioluminescent meso-pelagic fishes called myctophids. Because of their large abundance and of their diel vertical migration behaviour, these organisms have a major ecological importance in the southern ocean. However, the spatial distribution of the elephant seals prey, as well as the bio-physical processes affecting the dynamics of this distribution, are still poorly known. This thesis intends to investigate this issue using high sampling frequency bio-logging data collected by female southern elephant seals. This work is based on the analysis of elephant seals diving behaviour in relation to changes in the occurrence of prey encounter events detected from acceleration data. Our results suggest that (1) prey abundance decreases with depth and that their distribution tend to standardize, (2) prey are distributed into layers, (3) vertical constraints could modulate the prey density by acting on the vertical spread of these layers, (4) prey items are well dispersed in comparison to the perception range of elephant seals, and finally (5) that meso-scale eddies, notably their edges, play a structuring role in the prey distribution during the austral summer. Du fait de l’isolement géographique de l’océan austral et des conditions météorologiques qui y règnent, la collecte de données océanographiques par les moyens conventionnels est particulièrement couteuse dans cette région du globe. Pour pallier à ces difficultés, l’utilisation d’enregistreurs électroniques embarqués sur des prédateurs marins, et notamment sur les éléphants de mer austraux, s’est révélée être une approche intéressante. Les femelles éléphants de mer s’alimentent en grande partie de petits poissons ... Doctoral or Postdoctoral Thesis Elephant Seal Elephant Seals Southern Elephant Seal Southern Elephant Seals Southern Ocean Université de Nantes: HAL-UNIV-NANTES Austral Southern Ocean |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
French |
topic |
Southern elephant seals Bio-logging Myctophids Southern ocean Fine scale Diving behaviour Predator-prey interactions Eléphant de mer austral Myctophidés Océan austral Fine échelle Comportement de plongée Interactions prédateur-proies [SDV.SA]Life Sciences [q-bio]/Agricultural sciences |
spellingShingle |
Southern elephant seals Bio-logging Myctophids Southern ocean Fine scale Diving behaviour Predator-prey interactions Eléphant de mer austral Myctophidés Océan austral Fine échelle Comportement de plongée Interactions prédateur-proies [SDV.SA]Life Sciences [q-bio]/Agricultural sciences Le Bras, Yves Southern elephant seal, samplers of marine resources distribution |
topic_facet |
Southern elephant seals Bio-logging Myctophids Southern ocean Fine scale Diving behaviour Predator-prey interactions Eléphant de mer austral Myctophidés Océan austral Fine échelle Comportement de plongée Interactions prédateur-proies [SDV.SA]Life Sciences [q-bio]/Agricultural sciences |
description |
Because of the remoteness and harsh meteorological conditions of the southern ocean, data sampling is more costly in this area. Use of electronic devices attached to marine predators (Bio-logging), such as southern elephant seals, has emerged as an interesting approach to cope with this problem. Female southern elephant seals primarily feed on small bioluminescent meso-pelagic fishes called myctophids. Because of their large abundance and of their diel vertical migration behaviour, these organisms have a major ecological importance in the southern ocean. However, the spatial distribution of the elephant seals prey, as well as the bio-physical processes affecting the dynamics of this distribution, are still poorly known. This thesis intends to investigate this issue using high sampling frequency bio-logging data collected by female southern elephant seals. This work is based on the analysis of elephant seals diving behaviour in relation to changes in the occurrence of prey encounter events detected from acceleration data. Our results suggest that (1) prey abundance decreases with depth and that their distribution tend to standardize, (2) prey are distributed into layers, (3) vertical constraints could modulate the prey density by acting on the vertical spread of these layers, (4) prey items are well dispersed in comparison to the perception range of elephant seals, and finally (5) that meso-scale eddies, notably their edges, play a structuring role in the prey distribution during the austral summer. Du fait de l’isolement géographique de l’océan austral et des conditions météorologiques qui y règnent, la collecte de données océanographiques par les moyens conventionnels est particulièrement couteuse dans cette région du globe. Pour pallier à ces difficultés, l’utilisation d’enregistreurs électroniques embarqués sur des prédateurs marins, et notamment sur les éléphants de mer austraux, s’est révélée être une approche intéressante. Les femelles éléphants de mer s’alimentent en grande partie de petits poissons ... |
author2 |
Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS) Université de La Rochelle Christophe Guinet |
format |
Doctoral or Postdoctoral Thesis |
author |
Le Bras, Yves |
author_facet |
Le Bras, Yves |
author_sort |
Le Bras, Yves |
title |
Southern elephant seal, samplers of marine resources distribution |
title_short |
Southern elephant seal, samplers of marine resources distribution |
title_full |
Southern elephant seal, samplers of marine resources distribution |
title_fullStr |
Southern elephant seal, samplers of marine resources distribution |
title_full_unstemmed |
Southern elephant seal, samplers of marine resources distribution |
title_sort |
southern elephant seal, samplers of marine resources distribution |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://theses.hal.science/tel-01906055 https://theses.hal.science/tel-01906055/document https://theses.hal.science/tel-01906055/file/thesis_Yves_LE_BRAS_final2.pdf |
geographic |
Austral Southern Ocean |
geographic_facet |
Austral Southern Ocean |
genre |
Elephant Seal Elephant Seals Southern Elephant Seal Southern Elephant Seals Southern Ocean |
genre_facet |
Elephant Seal Elephant Seals Southern Elephant Seal Southern Elephant Seals Southern Ocean |
op_source |
https://theses.hal.science/tel-01906055 Sciences agricoles. Université de La Rochelle, 2017. Français. ⟨NNT : 2017LAROS036⟩ |
op_relation |
NNT: 2017LAROS036 tel-01906055 https://theses.hal.science/tel-01906055 https://theses.hal.science/tel-01906055/document https://theses.hal.science/tel-01906055/file/thesis_Yves_LE_BRAS_final2.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766401306242580480 |