Data underlying the publication: "Ontogenetic shifts by juvenile fishes highlight the need for habitat heterogeneity and connectivity in river restoration"

Habitat use shifted significantly with ontogeny across species. Larvae generally preferred shallow habitats (<50 cm depth), either in slow-flowing areas (e.g., asp, ide, monkey goby, nase, and whitefin gudgeon) or vegetated zones with macrophytes (e.g., bleak, bitterling, bream, round goby, and zander). Juveniles increasingly used deeper habitats (>50 cm depth), favouring fast-flowing areas (e.g., asp, barbel, ide) or deeper, non-flowing habitats (e.g., bream, zander).

Our findings thus highlight the critical importance of habitat heterogeneity and connectivity for riverine fish biodiversity. Restoration strategies should prioritise the creation of a mosaic of shallow, low-velocity habitats for larvae, alongside deeper, fast-flowing or sheltered areas for juveniles. Additionally, the movement of rheophilic species from floodplain habitats to the main river channel emphasises the need for maintaining continuous connectivity between floodplains and the river.