Downstream Migration of the European Eel (Anguilla Anguilla) in the Elbe River, Germany: Movement Patterns and the Potential Impact of Environmental Factors
2016 (English)In: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467, Vol. 32, no 4, 666-676 p.Article in journal (Refereed) Published
Recruitment of European eels (Anguilla anguilla) has declined to the extent that they have been added to the IUCN Red List of Threatened Species. Therefore, it is critical to ensure that eels complete their outward river migration in order to contribute to the available spawning stock. We conducted a 4-year (2007-2011) telemetry study to understand the migratory behaviour and potential impact of environmental factors on the eel during this critical life stage. Out of 399 female eels tagged with acoustic transmitters, only 28% demonstrated clear downstream migratory behaviour. Fifty-five percent were detected exhibiting no downstream migration behaviour and 17% were not detected at any monitoring station. Movement patterns of downstream-migrating (silver) eels were characterized by nocturnal activity and seasonal migration, with distinct peaks in autumn and spring. Migration was often discontinuous and exhibited phases of active locomotion and expanded stopovers. The most important determinants of movement activity were water temperature, cumulative precipitation and moonlight, although the significance varied by season and location in the river basin. Our results evidence a discontinuous, stepwise migration over an extended period. Furthermore, our findings indicate that migration success depends on holding duration prior to tagging and environmental predictors with varying importance depending on the season, as well as the locations of capture, tagging and release.
Place, publisher, year, edition, pages
2016. Vol. 32, no 4, 666-676 p.
acoustic telemetry, fish migration, environmental trigger, generalized linear model, handling effect, discontinuous migration, Anguilla anguilla, seasonal migration
Research subject Biology
IdentifiersURN: urn:nbn:se:kau:diva-42063DOI: 10.1002/rra.2881ISI: 000374704900013OAI: oai:DiVA.org:kau-42063DiVA: diva2:929693