Is feeding behaviour related to glass eel propensity to migrate? |
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| Authors: | Sarah Bureau du Colombier Patrick Lambert Agnès Bardonnet |
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| Institution: | 1. Station d''Hydrobiologie INRA, UMR ECOBIOP INRA/UPPA, Quartier Ibarron, 64310 St Pée sur Nivelle, France;2. CEMAGREF, Unité Ecosystèmes Estuariens et Poissons Migrateurs Amphihalins, 50 avenue de Verdun, 33612 Cestas Cedex, France |
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| Abstract: | Several studies have shown that eel diadromy is facultative and that migratory divergences may appear during glass eel estuarine migration. The origin of the differences in migratory behaviour among glass eels remains unclear but initial evidence supports the role of individual energetic and thyroidal status. Even if starvation is usually associated with glass eel migration, feeding does seem to occur in some glass eels. The aim of the present study was to investigate feeding behaviour and glass eel growth in relation to the propensity to migrate. Feeding rate and weight gain were higher in fish having a high propensity to migrate (M+ fish) than in fish having a low propensity to migrate (M− fish) in fed glass eels, whereas no clear difference in the variation in body weight was observed among unfed fish (controls). M− fish initially had lower percent dry weight than M+ fish, which suggests a link between appetite, propensity to migrate, and energy content. We discuss the role played by endocrine signals on these processes. In fish, thyroid hormones contribute to the control of growth and development. In addition, they play a role in flatfish and leptocephalus metamorphosis and appear to be involved in smolt and glass eel migratory behaviour. As such, they represent a good candidate which would promote the propensity to migrate as well as digestive system development. Their role in the hormonal control of food intake however remains vague. |
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| Keywords: | Anguilla anguilla feeding glass eel migratory behaviour physiology |
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