Is feeding behaviour related to glass eel propensity to migrate? | Le comportement alimentaire est-il lié à la propension des civelles à migrer ?
2008
Bureau Du Colombier, Sarah | Lambert, Patrick | Bardonnet, Agnes
Several studies showed that eel diadromy is facultative and that migratory divergences appear during glass eel estuarine migration. Origin of the differences in migratory behaviour among glass eels remains unclear but first evidence support the role of individual energetic and thyroidal status. Even if starvation usually is associated to glass eel migration, feeding seems to occur in certain glass eels. The aim of the present study was to investigate feeding behaviour and glass eel growth in relation to propensity to migrate. Feeding rate and weight gain were higher in M+ fish (fish having a high propensity to migrate) than in M- fish (fish having a low propensity to migrate) in fed glass eels, whereas no clear difference in the variation in body weight was observed among unfed fish (controls). M- fish had initially lower percent dry weight than M+ fish, which suggests a link between feeding motivation, propensity to migrate, and energy content. We hypothesise that differences in feeding behaviour in glass eels are linked to hormonal control which would also influence differences in energy content observed in individuals showing migratory divergences. Better understanding of migratory divergences in eels might help to properly evaluate and manage eel stocks.
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