Maps of the Dronne River. Black circles represent obstacles referenced in the French ROE database. White circles represent the fixed radio-telemetry receivers (Table 2). Diamonds represent eels release locations (Table 2). River flow is measured at Bonnes, immediately downstream the radio-telemetry receiver RAG. Physico-chemical parameters were monitored closed to the ATS receivers PAU, NAD and MON. Acronyms refer to towns or sites. REN, Renamon; DRO, Maison de la Dronne; PAU, Moulin de la Pauze; RIB, Ribérac; EPE, Epeluche; POL, Moulin de Poltot; RAG, Ragot; NAD, Nadelin; STA, Saint-Aulaye; CHA, Chamberlanne; PAR, Parcoul; ROC, La Roche-Chalais; MON, Monfourat.