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ESGL: Escapement of silver eels from the Grand-Lieu Lake to the sea
Trancart T; Feunteun E; Danet V; Carpentier A; Mazel V; Charrier F; Druet M; Acou A. (2018) Migration behaviour and escapement of European silver eels from a large lake and wetland system subject to water level management (Grand-Lieu Lake, France).

Availability: Creative Commons License This dataset is licensed under a Creative Commons Attribution 4.0 International License.

A telemetry survey of 50 acoustic and PIT-tagged female silver eels was performed during the 2015–2016 migration period. more

Current knowledge about the downstream migration of sexually mature European eels (Anguilla anguilla) remains incomplete, particularly in still water habitats such as lakes and wetlands subject to water level management. However, for the management of this endangered species, it is important to understand migration dynamics, and contribution to the breeding stock. This study aimed to assess the parameters that trigger and guide the migration of silver eels in the largest floodplain lake and associated wetlands in France (the sluice regulated Grand-Lieu Lake). A telemetry survey of 50 acoustic and PIT-tagged female silver eels was performed during the 2015–2016 migration period. We deployed a novel telemetric approach, using receivers to delimit several restricted virtual boxes to determine the instantaneous location of individuals and to transform simple discrete telemetric data into presence/absence data. The low numbers leaving the lake centre are probably explained by the lack of orienting water flows or other environmental clues, but whilst the fate of 34% (17/50) of the tagged eels is unknown, 18% (9/50) were caught by commercial fishermen. Modelling showed that detections were not clearly associated with environmental factors typically involved in riverine migrations (e.g. current velocity, atmospheric pressure and temperature) but they were particularly associated with higher and increasing water levels and, for eels exiting the lake, a sharp increase when sluice gates were opened to an effective gap of >75 cm. It is concluded that management of water levels and sluice gate opening during the migration period might aid escapement of silver eels.

Biology > Fish, Fisheries
Marine/Coastal, Brackish water, Acoustic telemetry, Acoustic Telemetry, Tracking, Pisces

Temporal coverage
25 September 2015 - 9 February 2016
Quasi continuous (< 1 min.)

Taxonomic coverage
Pisces [WoRMS]

National Natural History Museum Paris (MNHN), moredata creator

Related datasets
Parent dataset:
European Tracking Network (ETN) data, more

Dataset status: Completed
Data type: Data
Data origin: Research: field survey
Metadatarecord created: 2019-06-03
Information last updated: 2023-05-22
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