Toothed whale and shark depredation indicators: A case study from the Reunion Island and Seychelles pelagic longline fisheries
International audience Depredation in marine ecosystems is defined as the damage or removal of fish or bait from fishing gear by predators. Depredation raises concerns about the conservation of species involved, fisheries yield and profitability, and reference points based on stock assessment of dep...
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ftunimontpellier:oai:HAL:hal-04470948v1 2024-09-09T20:11:49+00:00 Toothed whale and shark depredation indicators: A case study from the Reunion Island and Seychelles pelagic longline fisheries Rabearisoa, Njaratiana Sabarros, Philippe Romanov, Evgeny Lucas, Vincent Bach, Pascal MARine Biodiversity Exploitation and Conservation (UMR MARBEC) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Centre technique d'appui à la pêche réunionnaise (CAP RUN - CITEB) France Seychelles Fishing Authority (SFA) (SFA) Université des Seychelles 2018 https://hal.science/hal-04470948 https://hal.science/hal-04470948/document https://hal.science/hal-04470948/file/e40ea6c77b399a6163e2d76c144c7998.pdf https://doi.org/10.1371/journal.pone.0202037 en eng HAL CCSD Public Library of Science info:eu-repo/semantics/altIdentifier/doi/10.1371/journal.pone.0202037 hal-04470948 https://hal.science/hal-04470948 https://hal.science/hal-04470948/document https://hal.science/hal-04470948/file/e40ea6c77b399a6163e2d76c144c7998.pdf doi:10.1371/journal.pone.0202037 info:eu-repo/semantics/OpenAccess ISSN: 1932-6203 EISSN: 1932-6203 PLoS ONE https://hal.science/hal-04470948 PLoS ONE, 2018, 13 (8), pp.e0202037. ⟨10.1371/journal.pone.0202037⟩ [SDV.SA.STP]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of fishery [SDE.BE]Environmental Sciences/Biodiversity and Ecology info:eu-repo/semantics/article Journal articles 2018 ftunimontpellier https://doi.org/10.1371/journal.pone.0202037 2024-07-30T23:34:04Z International audience Depredation in marine ecosystems is defined as the damage or removal of fish or bait from fishing gear by predators. Depredation raises concerns about the conservation of species involved, fisheries yield and profitability, and reference points based on stock assessment of depredated species. Therefore, the development of accurate indicators to assess the impact of depredation is needed. Both the Reunion Island and the Seychelles archipelago pelagic longline fisheries targeting swordfish (Xiphias gladius) and tuna (Thunnus spp.) are affected by depredation from toothed whales and pelagic sharks. In this study, we used fishery data collected between 2004 and 2015 to propose depredation indicators and to assess depredation levels in both fisheries. For both fisheries, the interaction rate (depredation occurrence) was significantly higher for shark compared to toothed whale depredation. However, when depredation occurred, toothed whale depredation impact was significantly higher than shark depredation impact, with higher depredation per unit effort (number of fish depredated per 1000 hooks) and damage rate (proportion of fish depredated per depredated set). The gross depredation rate in the Seychelles was 18.3%. A slight increase of the gross depredation rate was observed for the Reunion Island longline fleet from 2011 (4.1% in 2007–2010 and 4.4% in 2011–2015). Economic losses due to depredation were estimated by using these indicators and published official statistics. A loss of 0.09 EUR/hook due to depredation was estimated for the Reunion Island longline fleet, and 0.86 EUR/hook for the Seychelles. These results suggest a southward decreasing toothed whale and shark depredation gradient in the southwest Indian Ocean. Seychelles depredation levels are among the highest observed in the world revealing this area as a “hotspot” of interaction between pelagic longline fisheries and toothed whales. This study also highlights the need for a set of depredation indicators to allow for a global ... Article in Journal/Newspaper toothed whale toothed whales Université de Montpellier: HAL Indian |
institution |
Open Polar |
collection |
Université de Montpellier: HAL |
op_collection_id |
ftunimontpellier |
language |
English |
topic |
[SDV.SA.STP]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of fishery [SDE.BE]Environmental Sciences/Biodiversity and Ecology |
spellingShingle |
[SDV.SA.STP]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of fishery [SDE.BE]Environmental Sciences/Biodiversity and Ecology Rabearisoa, Njaratiana Sabarros, Philippe Romanov, Evgeny Lucas, Vincent Bach, Pascal Toothed whale and shark depredation indicators: A case study from the Reunion Island and Seychelles pelagic longline fisheries |
topic_facet |
[SDV.SA.STP]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of fishery [SDE.BE]Environmental Sciences/Biodiversity and Ecology |
description |
International audience Depredation in marine ecosystems is defined as the damage or removal of fish or bait from fishing gear by predators. Depredation raises concerns about the conservation of species involved, fisheries yield and profitability, and reference points based on stock assessment of depredated species. Therefore, the development of accurate indicators to assess the impact of depredation is needed. Both the Reunion Island and the Seychelles archipelago pelagic longline fisheries targeting swordfish (Xiphias gladius) and tuna (Thunnus spp.) are affected by depredation from toothed whales and pelagic sharks. In this study, we used fishery data collected between 2004 and 2015 to propose depredation indicators and to assess depredation levels in both fisheries. For both fisheries, the interaction rate (depredation occurrence) was significantly higher for shark compared to toothed whale depredation. However, when depredation occurred, toothed whale depredation impact was significantly higher than shark depredation impact, with higher depredation per unit effort (number of fish depredated per 1000 hooks) and damage rate (proportion of fish depredated per depredated set). The gross depredation rate in the Seychelles was 18.3%. A slight increase of the gross depredation rate was observed for the Reunion Island longline fleet from 2011 (4.1% in 2007–2010 and 4.4% in 2011–2015). Economic losses due to depredation were estimated by using these indicators and published official statistics. A loss of 0.09 EUR/hook due to depredation was estimated for the Reunion Island longline fleet, and 0.86 EUR/hook for the Seychelles. These results suggest a southward decreasing toothed whale and shark depredation gradient in the southwest Indian Ocean. Seychelles depredation levels are among the highest observed in the world revealing this area as a “hotspot” of interaction between pelagic longline fisheries and toothed whales. This study also highlights the need for a set of depredation indicators to allow for a global ... |
author2 |
MARine Biodiversity Exploitation and Conservation (UMR MARBEC) Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Centre technique d'appui à la pêche réunionnaise (CAP RUN - CITEB) France Seychelles Fishing Authority (SFA) (SFA) Université des Seychelles |
format |
Article in Journal/Newspaper |
author |
Rabearisoa, Njaratiana Sabarros, Philippe Romanov, Evgeny Lucas, Vincent Bach, Pascal |
author_facet |
Rabearisoa, Njaratiana Sabarros, Philippe Romanov, Evgeny Lucas, Vincent Bach, Pascal |
author_sort |
Rabearisoa, Njaratiana |
title |
Toothed whale and shark depredation indicators: A case study from the Reunion Island and Seychelles pelagic longline fisheries |
title_short |
Toothed whale and shark depredation indicators: A case study from the Reunion Island and Seychelles pelagic longline fisheries |
title_full |
Toothed whale and shark depredation indicators: A case study from the Reunion Island and Seychelles pelagic longline fisheries |
title_fullStr |
Toothed whale and shark depredation indicators: A case study from the Reunion Island and Seychelles pelagic longline fisheries |
title_full_unstemmed |
Toothed whale and shark depredation indicators: A case study from the Reunion Island and Seychelles pelagic longline fisheries |
title_sort |
toothed whale and shark depredation indicators: a case study from the reunion island and seychelles pelagic longline fisheries |
publisher |
HAL CCSD |
publishDate |
2018 |
url |
https://hal.science/hal-04470948 https://hal.science/hal-04470948/document https://hal.science/hal-04470948/file/e40ea6c77b399a6163e2d76c144c7998.pdf https://doi.org/10.1371/journal.pone.0202037 |
geographic |
Indian |
geographic_facet |
Indian |
genre |
toothed whale toothed whales |
genre_facet |
toothed whale toothed whales |
op_source |
ISSN: 1932-6203 EISSN: 1932-6203 PLoS ONE https://hal.science/hal-04470948 PLoS ONE, 2018, 13 (8), pp.e0202037. ⟨10.1371/journal.pone.0202037⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1371/journal.pone.0202037 hal-04470948 https://hal.science/hal-04470948 https://hal.science/hal-04470948/document https://hal.science/hal-04470948/file/e40ea6c77b399a6163e2d76c144c7998.pdf doi:10.1371/journal.pone.0202037 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1371/journal.pone.0202037 |
_version_ |
1809946419974373376 |