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Little information is available on governing factors of larval fish dispersal in natural river systems. Therefore, we aimed to describe dispersal and retention of marked larval nase carp, Chondrostoma nasus, along a shoreline nursery habitat of the River Danube. Based on a three-dimensional hydrodynamic model, we analyzed the influence of the hydraulic conditions on larval dispersal. We also related observed larval pathways to numerical particle tracing. Clear differences in the temporal drift pattern were due to significant differences in the hydrodynamic characteristics of the release stations. Some larvae remained in the study reach, most upstream of the release point. These were significantly larger than drifting larvae. We conclude that larval dispersal has an active component and that dispersal and retention patterns are dependent on the habitat structure and hydrodynamic characteristics of the releasing points. This emphasizes the importance of links between the location of spawning sites within the river and variation in flow during early development, the combination of which may contribute to successful recruitment of fluvial fish species. Peu de donnees sont presentement disponibles sur les facteurs qui regissent la dispersion des larves de poisson dans les systemes fluviaux naturels. Aussi, nous avons tente de decrire la dispersion et la retention de larves marquees de hotu, Chondrostoma nasus, le long d'un habitat de nourricerie littorale du fleuve Danube. A la lumiere d'un modele hydrodynamique tridimensionnel, nous avons analyse l'influence des conditions hydrauliques sur la dispersion des larves. Nous avons egalement relie les voies de dispersion des larves a des modeles numeriques de suivi de particules. Des differences nettes notees dans les motifs de derive dans le temps decoulaient de differences significatives des caracteristiques hydrodynamiques des sites de lacher. Certaines larves sont demeurees dans le troncon a l' etude, principalement en amont du point de lacher. Ces larves etaient significativement plus grandes que les larves derivantes. Nous concluons que la dispersion des larves comprend une composante active et que les motifs de dispersion et de retention dependent de la structure des habitats et des caracteristiques hydrodynamiques des points de lacher. Ces resultats soulignent l'importance des liens entre l'emplacement des sites de fraie dans un cours d'eau et les variations du debit durant le developpement precoce, la combinaison de ces deux facteurs pouvant contribuer au recrutement efficace d' especes de poissons fluviaux. [Traduit par la Redaction], Introduction Dispersal during early life history is a process fundamental to the population dynamics of aquatic organisms. In fishes it occurs predominantly during the embryonic and larval periods (Brown and [...]