1. Movements of Non-Migrant European Eels in an Urbanised Channel Linking a Mediterranean Lagoon to the Sea
- Author
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Raphaël Lagarde, François Bourrin, François Prellwitz, Elisabeth Faliex, Elsa Amilhat, Jason Peyre, and Gaël Simon
- Subjects
0106 biological sciences ,Mediterranean climate ,lcsh:Hydraulic engineering ,Geography, Planning and Development ,Population ,Anguilla anguilla ,Aquatic Science ,diadromy ,010603 evolutionary biology ,01 natural sciences ,Biochemistry ,Dredging ,lcsh:Water supply for domestic and industrial purposes ,lcsh:TC1-978 ,Tributary ,Ecosystem ,education ,Diel vertical migration ,Water Science and Technology ,lcsh:TD201-500 ,geography ,education.field_of_study ,geography.geographical_feature_category ,010604 marine biology & hydrobiology ,behaviour ,Fishery ,Habitat ,dual-frequency sonar ,Environmental science ,migratory fish ,acoustic camera ,Channel (geography) - Abstract
Transitional ecosystems and, particularly, Mediterranean lagoons represent important habitats for the European eel (Anguilla anguilla) population. In these habitats many anthropogenic pressures can disturb eel movements and, in turn, negatively affect the population. Despite the importance of movements during the non-migrant growing stage in eels, this topic is understudied in Mediterranean lagoons. We thus aim to describe the diel and seasonal phenology and the effect of environmental drivers on non-migrant eel movements. Videos obtained from an Adaptive Resolution Imaging Sonar (ARIS) acoustic camera that continuously recorded from October 2018 to April 2020 were processed to evaluate the daily number of eels swimming toward the lagoon. More than 60% of the 7207 eels observed were females with a size >, 45 cm. Movements were year-round and predominantly during the night. A Boosted Regression Tree analysis demonstrated that, among the 10 environmental drivers studied, flow velocity, water temperature, discharge of the main tributary, wind velocity and atmospheric pressure, had the strongest influence on eel movement activity. Non-migrant eel movements should be better incorporated into lagoon management plans through actions such as limiting dredging activities from 18:00 to midnight, especially when the water flows toward the lagoon and when the water temperature is higher than 12 °C.
- Published
- 2021
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