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Silver eel downstream migration in fragmented rivers: use of a Bayesian model to track movements triggering and duration

Drouineau, Hilaire and Bau, Frédérique and Alric, Alain and Deligne, Nicolas and Gomes, Peggy and Sagnes, Pierre Silver eel downstream migration in fragmented rivers: use of a Bayesian model to track movements triggering and duration. (2017) Aquatic Living Resources, 30 (5). 1-19. ISSN 0990-7440

(Document in English)

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Official URL: https://doi.org/10.1051/alr/2017003


Obstacles in rivers are considered to be one of the main threats to diadromous fish. As a result of the recent collapse of the European eel, the European Commission introduced a Regulation, requiring to reduce all sources of anthropogenic mortality, including those caused by passing through hydropower turbines. Improving knowledge about migration triggers and processes is crucial to assess and mitigate the impact of obstacles. In our study, we tracked 97 tagged silver eels in a fragmented river situated in the Western France (the River Dronne). Using the movement ecology framework, and implementing a Bayesian state-space model, we confirmed the influence of river discharge on migration triggering and he distance travelled by fish. We also demonstrated that, in our studied area, there is a small window of opportunity for migration. Moreover, we found that obstacles have a significant impact on distance travelled. Combined with the small window, this suggests that assessment of obstacles impact on downstream migration should not be limited to quantifying mortality at hydroelectric facilities, but should also consider the delay induced by obstacles, and its effects on escapement. The study also suggests that temporary turbines shutdown may mitigate the impacts of hydropower facilities in rivers with migration process similar to those observed here.

Item Type:Article
Additional Information:Thanks to EDP Sciences editor. The original PDF of the article can be found at https://www.alr-journal.org/articles/alr/abs/2017/01/alr160079/alr160079.html
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
French research institutions > Institut national de Recherche en Sciences et Technologies pour l'Environnement et l'Agriculture - IRSTEA (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
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Deposited On:25 Sep 2017 11:08

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