Metabolic loss of mass in glass eels at different salinities according to their propensity to migrate

► Glass eels were sorted out according to their propensity to migrate. ► Fish were individually placed at different salinities for 28 days. ► Results do not support higher energy cost of osmoregulation at sea. ► No link between migratory behaviour and salinity withstanding was evidenced. ► Fish energy expense might influence migratory behaviour.