Van Damme P. A. auteur aut IRD Cordova-Clavijo L. auteur aut IRD Baigun C. auteur aut IRD Hauser M. auteur aut IRD Doria C. R. D. auteur aut IRD Duponchelle Fabrice auteur aut IRD text journalArticle eng text/pdf reformatted digital access This paper explores the effects of two run-of-river dams (Jirau and Santo Antonio) built in cascade in the middle Madeira River (Brazil) on the interruption of long-distance migration mutes of the gilded catfish (Brachyplarystoma rousseauxii). A participative monitoring system was set up to compare capture by commercial fishers approximately 1500 kin upstream of the dams in Bolivia, before (1998-2007) and after (2015-2017) dam closure. A significant decrease in gilded catfish catches and in catch per unit effort was observed after dam closure, whereas no significant difference in mean weight was found. Back-estimation of age suggests that the few individuals remaining after dam closure in 2009 are a mixture of old homers that returned upstream before dam closure, and residents hatched after dam closure and trapped in the upper Madeira. Unless fishways in the Madeira River dams improve their efficiency, the gilded catfish might become rare and in danger of regional extinction in the upper Madeira basin in the next few years, negatively affecting river fisheries. specialized Environmental impact Fish migration Fishways Madeira dams River connectivity BOLIVIE AMAZONE BASSIN MADEIRA COURS D'EAU 036 034 062 17 4 e190118 [9 p.] 2019 1679-6225 https://www.documentation.ird.fr/hor/fdi:010077496 10.1590/1982-0224-20190118 1679-6225 [F B010077496] https://www.documentation.ird.fr/hor/fdi:010077496 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers20-01/010077496.pdf IRD - Base Horizon / Pleins textes 2020-02-05 2025-02-24 fdi:010077496 fre