Effects of body condition and water temperature on Anguilla anguilla glass eels migratory behavior

• Main Authors: Edeline, Eric, Lambert, Patrick, Rigaud, Christian, Elie, Pierre
• Other Authors: Biogéochimie et écologie des milieux continentaux (Bioemco), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes estuariens et poissons migrateurs amphihalins (UR EPBX), Centre national du machinisme agricole, du génie rural, des eaux et forêts (CEMAGREF)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2006
• Subjects: [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDV.BA]Life Sciences [q-bio]/Animal biology; [SDV.EE]Life Sciences [q-bio]/Ecology; environment; Anguilla anguilla
• Online Access: https://hal-bioemco.ccsd.cnrs.fr/bioemco-00353186

Glass eels arriving from the sea use alternative migratory tactics, leading either to the colonization of rivers or to an early settlement in marine or estuarine habitats. In the field, the migration may be environmentally affected by water temperature and the migratory behavior could be physiologically dependent on the body condition (energetic status). To investigate how these environmental and physiological effects on the migration are behaviorally mediated, we experimentally tested the effects of changes in water temperature and body condition on locomotor activity (upstream swimming) and salinity preference of Anguilla anguilla glass eels. Low water temperature reduced significantly both locomotor activity and preference for freshwater, in accordance with field data showing that low water temperatures hinder both the estuarine migration and river recruitment. Glass eels switched from a freshwater- towards a saltwater-preference as their body condition decreased, confirming that the energetic status may affect the migratory behavior. We suggest that, in the wild, this condition-dependent change in salinity preference of low body condition glass eels induces an early settlement in marine or estuarine habitats. Such a behavioral shift, stopping the energy expenditure linked to river-oriented migratory behavior, may be adaptive by limiting the probability of death due to exhaustion. Our results show that the glass eel migratory behavior, through locomotor activity and salinity preference, may be controlled by interacting physiological and environmental factors