Hélène Peltier , Matthieu Authier , Willy Dabin , Pierre Daniel , Cécile Dars , Fabien Demaret , Eleonore Meheust , Vincent Ridoux , Jérôme Spitz , Olivier Van Canneyt
{"title":"I sink therefore I am: 20 years of tagging small cetacean carcasses in the North-East Atlantic for bycatch estimation","authors":"Hélène Peltier , Matthieu Authier , Willy Dabin , Pierre Daniel , Cécile Dars , Fabien Demaret , Eleonore Meheust , Vincent Ridoux , Jérôme Spitz , Olivier Van Canneyt","doi":"10.1016/j.jnc.2025.127005","DOIUrl":null,"url":null,"abstract":"<div><div>For common dolphin (<em>Delphinus delphis</em> Linnaeus, 1758) and harbour porpoise (<em>Phocoena phocoena</em> Linnaeus, 1758), bycatch levels exceed the thresholds in the North-East Atlantic. Reverse drift modelling was developed to infer bycatch from stranding data. It is then necessary to define three parameters: the proportion of carcasses that float, the probability of a floating carcass drifting until stranding; and finally, the proportion of beached carcasses that are discovered and reported. The proportion of floating carcasses is the most influential corrective factor in the reverse drift modelling process. The objective of this study is to provide a better estimation of this proportion following bycatch in fishing gear. The predicted drift of 455 common dolphins and harbour porpoises that were tagged and discarded by fishing vessels was calculated by a drift prediction model (MOTHY). Of the tags deployed, stranding was predicted for 309 carcasses (278 common dolphins and 31 harbour porpoises), and 84 animals were discovered (78 common dolphins and 6 harbour porpoises). Bycatch in trammel nets and in midwater pair trawls resulted in a higher probability of these carcasses being recovered stranded. The predicted duration of the drift, on the other hand, had a negative effect on the number of strandings observed. The percentage of harbour porpoises that float was 27% (95% CI [12%,43%]), while it was 31% (95% CI [24%, 39%]) for common dolphins. These results contribute to the improvement of estimates of bycatch of small cetaceans inferred from strandings, which are used to inform conservation measures, particularly for the common dolphin in the North-East Atlantic.</div></div>","PeriodicalId":54898,"journal":{"name":"Journal for Nature Conservation","volume":"87 ","pages":"Article 127005"},"PeriodicalIF":2.5000,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal for Nature Conservation","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1617138125001827","RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIODIVERSITY CONSERVATION","Score":null,"Total":0}
引用次数: 0
Abstract
For common dolphin (Delphinus delphis Linnaeus, 1758) and harbour porpoise (Phocoena phocoena Linnaeus, 1758), bycatch levels exceed the thresholds in the North-East Atlantic. Reverse drift modelling was developed to infer bycatch from stranding data. It is then necessary to define three parameters: the proportion of carcasses that float, the probability of a floating carcass drifting until stranding; and finally, the proportion of beached carcasses that are discovered and reported. The proportion of floating carcasses is the most influential corrective factor in the reverse drift modelling process. The objective of this study is to provide a better estimation of this proportion following bycatch in fishing gear. The predicted drift of 455 common dolphins and harbour porpoises that were tagged and discarded by fishing vessels was calculated by a drift prediction model (MOTHY). Of the tags deployed, stranding was predicted for 309 carcasses (278 common dolphins and 31 harbour porpoises), and 84 animals were discovered (78 common dolphins and 6 harbour porpoises). Bycatch in trammel nets and in midwater pair trawls resulted in a higher probability of these carcasses being recovered stranded. The predicted duration of the drift, on the other hand, had a negative effect on the number of strandings observed. The percentage of harbour porpoises that float was 27% (95% CI [12%,43%]), while it was 31% (95% CI [24%, 39%]) for common dolphins. These results contribute to the improvement of estimates of bycatch of small cetaceans inferred from strandings, which are used to inform conservation measures, particularly for the common dolphin in the North-East Atlantic.
期刊介绍:
The Journal for Nature Conservation addresses concepts, methods and techniques for nature conservation. This international and interdisciplinary journal encourages collaboration between scientists and practitioners, including the integration of biodiversity issues with social and economic concepts. Therefore, conceptual, technical and methodological papers, as well as reviews, research papers, and short communications are welcomed from a wide range of disciplines, including theoretical ecology, landscape ecology, restoration ecology, ecological modelling, and others, provided that there is a clear connection and immediate relevance to nature conservation.
Manuscripts without any immediate conservation context, such as inventories, distribution modelling, genetic studies, animal behaviour, plant physiology, will not be considered for this journal; though such data may be useful for conservationists and managers in the future, this is outside of the current scope of the journal.