DEPREDATION PAR LES ORQUES (ORCINUS ORCA) ET LES CACHALOTS (PHYSETER MACROCEPHALUS) SUR LES PALANGRIERS A LA LEGINE AUSTRALE DANS LA ZEE DE L'ARCHIPEL DE CROZET
Over the last 50 years, fisheries have undergone a major decline worldwide. With an increased competition for resource, depredation (i.e. removal of catches on fishing gear) has recently become a major case of conflict between humans and marine predators. In this study I focused on the depredation o...
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Language: | French |
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2012
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Online Access: | https://theses.hal.science/tel-00910893 https://theses.hal.science/tel-00910893/document https://theses.hal.science/tel-00910893/file/TIXIER_Paul.pdf |
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ftccsdartic:oai:HAL:tel-00910893v1 2024-02-11T10:05:30+01:00 DEPREDATION PAR LES ORQUES (ORCINUS ORCA) ET LES CACHALOTS (PHYSETER MACROCEPHALUS) SUR LES PALANGRIERS A LA LEGINE AUSTRALE DANS LA ZEE DE L'ARCHIPEL DE CROZET Tixier, Paul Centre d'Études Biologiques de Chizé (CEBC) Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS) Université Aix-Marseille II Christophe GUINET(christophe.guinet@cebc.cnrs.fr) 2012-07-10 https://theses.hal.science/tel-00910893 https://theses.hal.science/tel-00910893/document https://theses.hal.science/tel-00910893/file/TIXIER_Paul.pdf fr fre HAL CCSD tel-00910893 https://theses.hal.science/tel-00910893 https://theses.hal.science/tel-00910893/document https://theses.hal.science/tel-00910893/file/TIXIER_Paul.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-00910893 Sciences de l'environnement. Université Aix-Marseille II, 2012. Français. ⟨NNT : ⟩ DEPREDATION KILLER WHALE MITIGATION SOCIAL ORGANIZATION DEMOGRAPHY FEEDING ECOLOGY CONSERVATION [SDE]Environmental Sciences info:eu-repo/semantics/doctoralThesis Theses 2012 ftccsdartic 2024-01-27T23:27:02Z Over the last 50 years, fisheries have undergone a major decline worldwide. With an increased competition for resource, depredation (i.e. removal of catches on fishing gear) has recently become a major case of conflict between humans and marine predators. In this study I focused on the depredation on Patagonian toothfish fisheries by killer and sperm whales in the Crozet EEZ. The first part of the study aimed at assessing the socio-economic consequences of this issue. Killer and sperm whales have interacted with 43.3% and 57.5% of longlines (n = 5 438) respectively from 2003 to 2010. Killer whales, alone or co-occurring with sperm whales were responsible for an estimated loss of 926 ± 76 tons of toothfish over that period, which represents 17.7% of the total catch. Three operational factors were identified as influencing significantly depredation levels: i) the use of short longlines (<5000m) in absence of killer whales, ii) the displacement of vessels on distances >75 km to leave the whales behind and iii) the use of longline hauling speed > 50 ham.min-1. The second aim of the study was to investigate the consequences of depredation on the Crozet killer whale population. The long term monitoring of individuals showed divergent demographic trajectories related to the depredation level of matrilines. During the 1990s, matrilines interacting with fisheries have undergone a high mortality due to lethal interactions with illegal fishing vessels using explosives to repel the whales. Since 2003 and the end of illegal fisheries, martilines interacting the most with fisheries have now clear demographic advantages with better survival and reproduction that other matrilines, suggesting the benefits of depredation. As depredation is a growing issue in the world, this study has great implications, on one hand because it involves a productive collaboration between fishermen, government and researchers, and on the other hand because it provides accurate insights on conservation priorities of such an issue. C'est ... Doctoral or Postdoctoral Thesis Killer Whale Orca Orcinus orca Patagonian Toothfish Physeter macrocephalus Killer whale Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Orques ENVELOPE(140.031,140.031,-66.669,-66.669) |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
French |
topic |
DEPREDATION KILLER WHALE MITIGATION SOCIAL ORGANIZATION DEMOGRAPHY FEEDING ECOLOGY CONSERVATION [SDE]Environmental Sciences |
spellingShingle |
DEPREDATION KILLER WHALE MITIGATION SOCIAL ORGANIZATION DEMOGRAPHY FEEDING ECOLOGY CONSERVATION [SDE]Environmental Sciences Tixier, Paul DEPREDATION PAR LES ORQUES (ORCINUS ORCA) ET LES CACHALOTS (PHYSETER MACROCEPHALUS) SUR LES PALANGRIERS A LA LEGINE AUSTRALE DANS LA ZEE DE L'ARCHIPEL DE CROZET |
topic_facet |
DEPREDATION KILLER WHALE MITIGATION SOCIAL ORGANIZATION DEMOGRAPHY FEEDING ECOLOGY CONSERVATION [SDE]Environmental Sciences |
description |
Over the last 50 years, fisheries have undergone a major decline worldwide. With an increased competition for resource, depredation (i.e. removal of catches on fishing gear) has recently become a major case of conflict between humans and marine predators. In this study I focused on the depredation on Patagonian toothfish fisheries by killer and sperm whales in the Crozet EEZ. The first part of the study aimed at assessing the socio-economic consequences of this issue. Killer and sperm whales have interacted with 43.3% and 57.5% of longlines (n = 5 438) respectively from 2003 to 2010. Killer whales, alone or co-occurring with sperm whales were responsible for an estimated loss of 926 ± 76 tons of toothfish over that period, which represents 17.7% of the total catch. Three operational factors were identified as influencing significantly depredation levels: i) the use of short longlines (<5000m) in absence of killer whales, ii) the displacement of vessels on distances >75 km to leave the whales behind and iii) the use of longline hauling speed > 50 ham.min-1. The second aim of the study was to investigate the consequences of depredation on the Crozet killer whale population. The long term monitoring of individuals showed divergent demographic trajectories related to the depredation level of matrilines. During the 1990s, matrilines interacting with fisheries have undergone a high mortality due to lethal interactions with illegal fishing vessels using explosives to repel the whales. Since 2003 and the end of illegal fisheries, martilines interacting the most with fisheries have now clear demographic advantages with better survival and reproduction that other matrilines, suggesting the benefits of depredation. As depredation is a growing issue in the world, this study has great implications, on one hand because it involves a productive collaboration between fishermen, government and researchers, and on the other hand because it provides accurate insights on conservation priorities of such an issue. C'est ... |
author2 |
Centre d'Études Biologiques de Chizé (CEBC) Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS) Université Aix-Marseille II Christophe GUINET(christophe.guinet@cebc.cnrs.fr) |
format |
Doctoral or Postdoctoral Thesis |
author |
Tixier, Paul |
author_facet |
Tixier, Paul |
author_sort |
Tixier, Paul |
title |
DEPREDATION PAR LES ORQUES (ORCINUS ORCA) ET LES CACHALOTS (PHYSETER MACROCEPHALUS) SUR LES PALANGRIERS A LA LEGINE AUSTRALE DANS LA ZEE DE L'ARCHIPEL DE CROZET |
title_short |
DEPREDATION PAR LES ORQUES (ORCINUS ORCA) ET LES CACHALOTS (PHYSETER MACROCEPHALUS) SUR LES PALANGRIERS A LA LEGINE AUSTRALE DANS LA ZEE DE L'ARCHIPEL DE CROZET |
title_full |
DEPREDATION PAR LES ORQUES (ORCINUS ORCA) ET LES CACHALOTS (PHYSETER MACROCEPHALUS) SUR LES PALANGRIERS A LA LEGINE AUSTRALE DANS LA ZEE DE L'ARCHIPEL DE CROZET |
title_fullStr |
DEPREDATION PAR LES ORQUES (ORCINUS ORCA) ET LES CACHALOTS (PHYSETER MACROCEPHALUS) SUR LES PALANGRIERS A LA LEGINE AUSTRALE DANS LA ZEE DE L'ARCHIPEL DE CROZET |
title_full_unstemmed |
DEPREDATION PAR LES ORQUES (ORCINUS ORCA) ET LES CACHALOTS (PHYSETER MACROCEPHALUS) SUR LES PALANGRIERS A LA LEGINE AUSTRALE DANS LA ZEE DE L'ARCHIPEL DE CROZET |
title_sort |
depredation par les orques (orcinus orca) et les cachalots (physeter macrocephalus) sur les palangriers a la legine australe dans la zee de l'archipel de crozet |
publisher |
HAL CCSD |
publishDate |
2012 |
url |
https://theses.hal.science/tel-00910893 https://theses.hal.science/tel-00910893/document https://theses.hal.science/tel-00910893/file/TIXIER_Paul.pdf |
long_lat |
ENVELOPE(140.031,140.031,-66.669,-66.669) |
geographic |
Orques |
geographic_facet |
Orques |
genre |
Killer Whale Orca Orcinus orca Patagonian Toothfish Physeter macrocephalus Killer whale |
genre_facet |
Killer Whale Orca Orcinus orca Patagonian Toothfish Physeter macrocephalus Killer whale |
op_source |
https://theses.hal.science/tel-00910893 Sciences de l'environnement. Université Aix-Marseille II, 2012. Français. ⟨NNT : ⟩ |
op_relation |
tel-00910893 https://theses.hal.science/tel-00910893 https://theses.hal.science/tel-00910893/document https://theses.hal.science/tel-00910893/file/TIXIER_Paul.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1790602562163965952 |