Glass eel (Anguilla anguilla L. 1758) feeding behaviour during upstream migration in an artificial waterway

The transition from marine to fresh water is a challenging task for juvenile eels. Thiscritical step in the early eels' life is preceded by a metamorphosis from the oceaniclarval to the continental glass eel stage, requiring major energy-demanding morpho-logical, physiological and behavioural m...

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Bibliographic Details
Published in:Journal of Fish Biology
Main Authors: Van Wichelen, Jeroen, Verhelst, Pieterjan, Perneel, Michiel, Van Driessche, Charlotte, Buysse, David, Belpaire, Claude, Coeck, Johan, De Troch, Marleen
Format: Article in Journal/Newspaper
Language:English
Published: 2022
Subjects:
Biology and Life Sciences
Aquatic Science
Ecology
Evolution
Behavior and Systematics
diet
digestive tract analysis
drainage canal
North Sea
tidal barrage
ADJUSTED BARRIER
ESTUARINE FISH
RECRUITMENT
SALINITY
GROWTH
PIGMENTATION
SWIMBLADDER
TEMPERATURE
MANAGEMENT
INFECTION
Anguilla anguilla
Copepods
Online Access:https://biblio.ugent.be/publication/8765013
http://hdl.handle.net/1854/LU-8765013
https://doi.org/10.1111/jfb.15171
https://biblio.ugent.be/publication/8765013/file/8772465
Description
Summary:The transition from marine to fresh water is a challenging task for juvenile eels. Thiscritical step in the early eels' life is preceded by a metamorphosis from the oceaniclarval to the continental glass eel stage, requiring major energy-demanding morpho-logical, physiological and behavioural modifications during which time these animalsdo not feed. The success of the glass eels’inland migration after metamorphosis willlargely depend on remaining energy levels, which can be supplemented only byresuming food uptake. Although it is crucial for their survival and the maintenance ofthe population, the feeding behaviour of glass eels is still an understudied aspect ofthe eels’complex life cycle. Many uncertainties about the phenology, diet, potentialprey preferences and their relation with migration modus (migratoryvs. sedentary)still remain. In this study, the authors analysed the stomach and gut contents of458 European glass eels (Anguilla anguillaL. 1758) captured in a drainage canal con-necting a small mesotidal estuary with an adjacent polder area during the springmigration seasons of 2016 and 2017. They demonstrated that although glass eelsstarted feeding briefly upon arrival in the estuary, food uptake for early arrivals wasrestricted to a minority that sparsely feed on detritus and some worm-like benthicinvertebrates. Along the season, food uptake intensified eventually engaging all glasseels and their dietary palette diversified including a wide array of planktonic and ben-thic organisms. Crustacean plankton (mainly cyclopoid copepods) was an importantpart of the glass eel diet, whereas benthic oligochaetes were less abundant as foodsource in spite of their high presence in the sediments. No clear differences in feed-ing behaviour could be observed between migratory and sedentary glass eels. Thisstudy showed that glass eels can use highly artificial and dynamic drainage canals asfeeding ground during their critical marine/freshwater transition. This outcome is alsoa plea to improve the accessibility of ...

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