Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic.
International audience Fisheries interactions have been implicated in the decline of many marine vertebrates worldwide. In the eastern North Atlantic, at least 1000 common dolphins (Delphinus delphis) are bycaught each year, particularly in pelagic pair-trawls. We have assessed the resulting impact...
Published in: | PLoS ONE |
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Main Authors: | , , , , , |
Other Authors: | , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2012
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Online Access: | https://hal.science/hal-00686808 https://doi.org/10.1371/journal.pone.0032615 |
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English |
topic |
[SDE]Environmental Sciences |
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[SDE]Environmental Sciences Mannocci, Laura Dabin, Willy Augeraud-Véron, Emmanuelle Dupuy, Jean-François Barbraud, Christophe Ridoux, Vincent Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic. |
topic_facet |
[SDE]Environmental Sciences |
description |
International audience Fisheries interactions have been implicated in the decline of many marine vertebrates worldwide. In the eastern North Atlantic, at least 1000 common dolphins (Delphinus delphis) are bycaught each year, particularly in pelagic pair-trawls. We have assessed the resulting impact of bycatch on this population using a demographic modeling approach. We relied on a sample of females stranded along the French Atlantic and western Channel coasts. Strandings represent an extensive source of demographic information to monitor our study population. Necropsy analysis provided an estimate of individual age and reproductive state. Then we estimated effective survivorship (including natural and human-induced mortality), age at first reproduction and pregnancy rates. Reproductive parameters were consistent with literature, but effective survivorship was unexpectedly low. Demographic parameters were then used as inputs in two models. A constant parameter matrix proposed an effective growth rate of -5.5±0.5%, corresponding to the current situation (including bycatch mortality). Subsequently, deterministic projections suggested that the population would be reduced to 20% of its current size in 30 years and would be extinct in 100 years. The demographic invariant model suggested a maximum growth rate of +4.5±0.09%, corresponding to the optimal demographic situation. Then, a risk analysis incorporating Potential Biological Removal (PBR), based on two plausible scenarii for stock structure suggested that bycatch level was unsustainable for the neritic population of the Bay of Biscay under a two-stock scenario. In depth assessment of stock structure and improved observer programs to provide scientifically robust bycatch estimates are needed. Effective conservation measures would be reducing bycatch to less than 50% of the current level in the neritic stock to reach PBR. Our approach provided indicators of the status and trajectory of the common dolphin population in the eastern North Atlantic and therefore ... |
author2 |
LIttoral ENvironnement et Sociétés (LIENSs) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS) Fédération de Recherche en Environnement pour le Développement Durable - FR 3097 (FREDD) Mathématiques, Image et Applications - EA 3165 (MIA) La Rochelle Université (ULR) Institut de Recherche Mathématique de Rennes (IRMAR) Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes) Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-INSTITUT AGRO Agrocampus Ouest Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro) Centre d'Études Biologiques de Chizé (CEBC) Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS) Centre de Recherche sur les Mammifères Marins (CRMM) |
format |
Article in Journal/Newspaper |
author |
Mannocci, Laura Dabin, Willy Augeraud-Véron, Emmanuelle Dupuy, Jean-François Barbraud, Christophe Ridoux, Vincent |
author_facet |
Mannocci, Laura Dabin, Willy Augeraud-Véron, Emmanuelle Dupuy, Jean-François Barbraud, Christophe Ridoux, Vincent |
author_sort |
Mannocci, Laura |
title |
Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic. |
title_short |
Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic. |
title_full |
Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic. |
title_fullStr |
Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic. |
title_full_unstemmed |
Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic. |
title_sort |
assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic. |
publisher |
HAL CCSD |
publishDate |
2012 |
url |
https://hal.science/hal-00686808 https://doi.org/10.1371/journal.pone.0032615 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
ISSN: 1932-6203 EISSN: 1932-6203 PLoS ONE https://hal.science/hal-00686808 PLoS ONE, 2012, 7 (2), pp.e32615. ⟨10.1371/journal.pone.0032615⟩ |
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op_doi |
https://doi.org/10.1371/journal.pone.0032615 |
container_title |
PLoS ONE |
container_volume |
7 |
container_issue |
2 |
container_start_page |
e32615 |
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1798850542221393920 |
spelling |
ftinstagro:oai:HAL:hal-00686808v1 2024-05-12T08:07:46+00:00 Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern north atlantic. Mannocci, Laura Dabin, Willy Augeraud-Véron, Emmanuelle Dupuy, Jean-François Barbraud, Christophe Ridoux, Vincent LIttoral ENvironnement et Sociétés (LIENSs) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS) Fédération de Recherche en Environnement pour le Développement Durable - FR 3097 (FREDD) Mathématiques, Image et Applications - EA 3165 (MIA) La Rochelle Université (ULR) Institut de Recherche Mathématique de Rennes (IRMAR) Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes) Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-INSTITUT AGRO Agrocampus Ouest Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro) Centre d'Études Biologiques de Chizé (CEBC) Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS) Centre de Recherche sur les Mammifères Marins (CRMM) 2012 https://hal.science/hal-00686808 https://doi.org/10.1371/journal.pone.0032615 en eng HAL CCSD Public Library of Science info:eu-repo/semantics/altIdentifier/doi/10.1371/journal.pone.0032615 info:eu-repo/semantics/altIdentifier/pmid/22393423 hal-00686808 https://hal.science/hal-00686808 doi:10.1371/journal.pone.0032615 PUBMED: 22393423 PUBMEDCENTRAL: PMC3290591 ISSN: 1932-6203 EISSN: 1932-6203 PLoS ONE https://hal.science/hal-00686808 PLoS ONE, 2012, 7 (2), pp.e32615. ⟨10.1371/journal.pone.0032615⟩ [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2012 ftinstagro https://doi.org/10.1371/journal.pone.0032615 2024-04-18T17:05:16Z International audience Fisheries interactions have been implicated in the decline of many marine vertebrates worldwide. In the eastern North Atlantic, at least 1000 common dolphins (Delphinus delphis) are bycaught each year, particularly in pelagic pair-trawls. We have assessed the resulting impact of bycatch on this population using a demographic modeling approach. We relied on a sample of females stranded along the French Atlantic and western Channel coasts. Strandings represent an extensive source of demographic information to monitor our study population. Necropsy analysis provided an estimate of individual age and reproductive state. Then we estimated effective survivorship (including natural and human-induced mortality), age at first reproduction and pregnancy rates. Reproductive parameters were consistent with literature, but effective survivorship was unexpectedly low. Demographic parameters were then used as inputs in two models. A constant parameter matrix proposed an effective growth rate of -5.5±0.5%, corresponding to the current situation (including bycatch mortality). Subsequently, deterministic projections suggested that the population would be reduced to 20% of its current size in 30 years and would be extinct in 100 years. The demographic invariant model suggested a maximum growth rate of +4.5±0.09%, corresponding to the optimal demographic situation. Then, a risk analysis incorporating Potential Biological Removal (PBR), based on two plausible scenarii for stock structure suggested that bycatch level was unsustainable for the neritic population of the Bay of Biscay under a two-stock scenario. In depth assessment of stock structure and improved observer programs to provide scientifically robust bycatch estimates are needed. Effective conservation measures would be reducing bycatch to less than 50% of the current level in the neritic stock to reach PBR. Our approach provided indicators of the status and trajectory of the common dolphin population in the eastern North Atlantic and therefore ... Article in Journal/Newspaper North Atlantic Portail HAL Institut Agro PLoS ONE 7 2 e32615 |