Studie of the migration of several anadromous spesies (Coregonus oxyrinchus; Salmo salar; Salmo trutta; Petromyzon marinus; Lampetra fluviatilis) and habitat use of several rheophillic species (Leuciscus idus; Chondrostoma nasus; Barbus barbus) in the Nederrijn-Lek (Netherlands), between 2025-2027.