Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay
International audience Marine megafauna plays an important functional role in marine ecosystems as top predators but are threatened by a wide range of anthropogenic activities. Bycatch, the incidental capture of non-targeted species in commercial and recreational fisheries, is of particular concern...
Published in: | Frontiers in Marine Science |
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Main Authors: | , , , , , , , , |
Other Authors: | , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2022
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Subjects: | |
Online Access: | https://hal.science/hal-03572951 https://hal.science/hal-03572951/document https://hal.science/hal-03572951/file/fmars-08-795942-1.pdf https://doi.org/10.3389/fmars.2021.795942 |
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ftunivrochelle:oai:HAL:hal-03572951v1 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
HAL - Université de La Rochelle |
op_collection_id |
ftunivrochelle |
language |
English |
topic |
additional mortality anthropogenic activities modelling non-representative samples conservation small cetaceans fisheries post-stratification [SDE]Environmental Sciences |
spellingShingle |
additional mortality anthropogenic activities modelling non-representative samples conservation small cetaceans fisheries post-stratification [SDE]Environmental Sciences Rouby, Etienne Dubroca, Laurent Cloâtre, Thomas Demanèche, Sebastien Genu, Mathieu Macleod, Kelly Peltier, Hélène Ridoux, Vincent Authier, Matthieu Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay |
topic_facet |
additional mortality anthropogenic activities modelling non-representative samples conservation small cetaceans fisheries post-stratification [SDE]Environmental Sciences |
description |
International audience Marine megafauna plays an important functional role in marine ecosystems as top predators but are threatened by a wide range of anthropogenic activities. Bycatch, the incidental capture of non-targeted species in commercial and recreational fisheries, is of particular concern for small cetacean species, such as dolphins and porpoises. In the North-East Atlantic, common dolphin ( Delphinus delphis , Linné 1758) bycatch has been increasing and associated with large numbers of animals stranding during winter on the French Atlantic seashore since at least 2017. However, uncertainties around the true magnitude of common dolphin bycatch and the fisheries involved have led to delays in the implementation of mitigation measures. Current data collection on dolphin bycatch in France is with non-dedicated observers deployed on vessels for the purpose of national fisheries sampling programmes. These data cannot be assumed representative of the whole fisheries' bycatch events. This feature makes it difficult to use classic ratio estimators since they require a truly randomised sample of the fishery by dedicated observers. We applied a newly developed approach, regularised multilevel regression with post-stratification, to estimate total bycatch from unrepresentative samples and total fishing effort. The latter is needed for post-stratification and the former is analysed in a Bayesian framework with multilevel regression to regularise and better predict bycatch risk. We estimated the number of bycaught dolphins for each week and 10 International Council for the Exploration of the Sea (ICES) divisions from 2004 to 2020 by estimating jointly bycatch risk, haul duration, and the number of hauls per days at sea (DaS). Bycatch risk in pair trawlers flying the French flag was the highest in winter 2017 and 2019 and was associated with the longest haul durations. ICES divisions 8.a and 8.b (shelf part of the Bay of Biscay) were estimated to have the highest common dolphin bycatch. Our results were consistent ... |
author2 |
Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) Observatoire pour la Conservation de la Mégafaune Marine (PELAGIS) LIttoral ENvironnement et Sociétés (LIENSs) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Laboratoire Ressources Halieutiques de Port-en-Bessin (LRHPB) Unité Halieutique Manche Mer du Nord (HMMN) Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) Unité Sciences et Technologies Halieutiques (STH) Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) Joint Nature Conservation Committee (UK) Inverdee House |
format |
Article in Journal/Newspaper |
author |
Rouby, Etienne Dubroca, Laurent Cloâtre, Thomas Demanèche, Sebastien Genu, Mathieu Macleod, Kelly Peltier, Hélène Ridoux, Vincent Authier, Matthieu |
author_facet |
Rouby, Etienne Dubroca, Laurent Cloâtre, Thomas Demanèche, Sebastien Genu, Mathieu Macleod, Kelly Peltier, Hélène Ridoux, Vincent Authier, Matthieu |
author_sort |
Rouby, Etienne |
title |
Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay |
title_short |
Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay |
title_full |
Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay |
title_fullStr |
Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay |
title_full_unstemmed |
Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay |
title_sort |
estimating bycatch from non-representative samples (ii): a case study of pair trawlers and common dolphins in the bay of biscay |
publisher |
HAL CCSD |
publishDate |
2022 |
url |
https://hal.science/hal-03572951 https://hal.science/hal-03572951/document https://hal.science/hal-03572951/file/fmars-08-795942-1.pdf https://doi.org/10.3389/fmars.2021.795942 |
genre |
North East Atlantic |
genre_facet |
North East Atlantic |
op_source |
ISSN: 2296-7745 Frontiers in Marine Science https://hal.science/hal-03572951 Frontiers in Marine Science, 2022, 8, pp.795942. ⟨10.3389/fmars.2021.795942⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.3389/fmars.2021.795942 hal-03572951 https://hal.science/hal-03572951 https://hal.science/hal-03572951/document https://hal.science/hal-03572951/file/fmars-08-795942-1.pdf doi:10.3389/fmars.2021.795942 |
op_rights |
http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.3389/fmars.2021.795942 |
container_title |
Frontiers in Marine Science |
container_volume |
8 |
_version_ |
1797589266307481600 |
spelling |
ftunivrochelle:oai:HAL:hal-03572951v1 2024-04-28T08:31:55+00:00 Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay Rouby, Etienne Dubroca, Laurent Cloâtre, Thomas Demanèche, Sebastien Genu, Mathieu Macleod, Kelly Peltier, Hélène Ridoux, Vincent Authier, Matthieu Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) Observatoire pour la Conservation de la Mégafaune Marine (PELAGIS) LIttoral ENvironnement et Sociétés (LIENSs) La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Laboratoire Ressources Halieutiques de Port-en-Bessin (LRHPB) Unité Halieutique Manche Mer du Nord (HMMN) Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) Unité Sciences et Technologies Halieutiques (STH) Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER) Joint Nature Conservation Committee (UK) Inverdee House 2022-01-13 https://hal.science/hal-03572951 https://hal.science/hal-03572951/document https://hal.science/hal-03572951/file/fmars-08-795942-1.pdf https://doi.org/10.3389/fmars.2021.795942 en eng HAL CCSD Frontiers Media info:eu-repo/semantics/altIdentifier/doi/10.3389/fmars.2021.795942 hal-03572951 https://hal.science/hal-03572951 https://hal.science/hal-03572951/document https://hal.science/hal-03572951/file/fmars-08-795942-1.pdf doi:10.3389/fmars.2021.795942 http://creativecommons.org/licenses/by/ info:eu-repo/semantics/OpenAccess ISSN: 2296-7745 Frontiers in Marine Science https://hal.science/hal-03572951 Frontiers in Marine Science, 2022, 8, pp.795942. ⟨10.3389/fmars.2021.795942⟩ additional mortality anthropogenic activities modelling non-representative samples conservation small cetaceans fisheries post-stratification [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2022 ftunivrochelle https://doi.org/10.3389/fmars.2021.795942 2024-04-03T15:15:57Z International audience Marine megafauna plays an important functional role in marine ecosystems as top predators but are threatened by a wide range of anthropogenic activities. Bycatch, the incidental capture of non-targeted species in commercial and recreational fisheries, is of particular concern for small cetacean species, such as dolphins and porpoises. In the North-East Atlantic, common dolphin ( Delphinus delphis , Linné 1758) bycatch has been increasing and associated with large numbers of animals stranding during winter on the French Atlantic seashore since at least 2017. However, uncertainties around the true magnitude of common dolphin bycatch and the fisheries involved have led to delays in the implementation of mitigation measures. Current data collection on dolphin bycatch in France is with non-dedicated observers deployed on vessels for the purpose of national fisheries sampling programmes. These data cannot be assumed representative of the whole fisheries' bycatch events. This feature makes it difficult to use classic ratio estimators since they require a truly randomised sample of the fishery by dedicated observers. We applied a newly developed approach, regularised multilevel regression with post-stratification, to estimate total bycatch from unrepresentative samples and total fishing effort. The latter is needed for post-stratification and the former is analysed in a Bayesian framework with multilevel regression to regularise and better predict bycatch risk. We estimated the number of bycaught dolphins for each week and 10 International Council for the Exploration of the Sea (ICES) divisions from 2004 to 2020 by estimating jointly bycatch risk, haul duration, and the number of hauls per days at sea (DaS). Bycatch risk in pair trawlers flying the French flag was the highest in winter 2017 and 2019 and was associated with the longest haul durations. ICES divisions 8.a and 8.b (shelf part of the Bay of Biscay) were estimated to have the highest common dolphin bycatch. Our results were consistent ... Article in Journal/Newspaper North East Atlantic HAL - Université de La Rochelle Frontiers in Marine Science 8 |