Estimating Bycatch From Non-representative Samples (II): A Case Study of Pair Trawlers and Common Dolphins in the Bay of Biscay
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 spec...
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fttriple:oai:gotriple.eu:10670/1.cqsz4i 2023-05-15T17:38:39+02:00 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 https://doi.org/10.3389/fmars.2021.795942 https://archimer.ifremer.fr/doc/00744/85628/90752.pdf https://archimer.ifremer.fr/doc/00744/85628/ en eng Frontiers Media SA doi:10.3389/fmars.2021.795942 10670/1.cqsz4i https://archimer.ifremer.fr/doc/00744/85628/90752.pdf https://archimer.ifremer.fr/doc/00744/85628/ other Archimer, archive institutionnelle de l'Ifremer Frontiers in Marine Science (2296-7745) (Frontiers Media SA), 2022-01 , Vol. 8 , P. 795942 (15p.) envir droit Text https://vocabularies.coar-repositories.org/resource_types/c_18cf/ fttriple https://doi.org/10.3389/fmars.2021.795942 2023-01-22T16:48:51Z 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 with independent estimates ... Text North East Atlantic Unknown Frontiers in Marine Science 8 |
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envir droit 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 |
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envir droit |
description |
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 with independent estimates ... |
format |
Text |
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 |
Frontiers Media SA |
url |
https://doi.org/10.3389/fmars.2021.795942 https://archimer.ifremer.fr/doc/00744/85628/90752.pdf https://archimer.ifremer.fr/doc/00744/85628/ |
genre |
North East Atlantic |
genre_facet |
North East Atlantic |
op_source |
Archimer, archive institutionnelle de l'Ifremer Frontiers in Marine Science (2296-7745) (Frontiers Media SA), 2022-01 , Vol. 8 , P. 795942 (15p.) |
op_relation |
doi:10.3389/fmars.2021.795942 10670/1.cqsz4i https://archimer.ifremer.fr/doc/00744/85628/90752.pdf https://archimer.ifremer.fr/doc/00744/85628/ |
op_rights |
other |
op_doi |
https://doi.org/10.3389/fmars.2021.795942 |
container_title |
Frontiers in Marine Science |
container_volume |
8 |
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1766139186746753024 |