<p>In recent years, the population of the European smelt (<i>Osmerus eperlanus</i>) in the Tidal Elbe has diminished significantly. In the transdisciplinary study presented here, we traced the interconnections of multiple stressors leading to this decline, as well as the consequences of losing smelt from the estuary for the socio-cultural system in the region. We used a bowtie approach to identify potential intervention points that could mitigate or prevent harmful outcomes and discussed the political and social feasibility of management options. Our findings show that historical and recent river management has deteriorating effects on the morphology and ecology of the Tidal Elbe, with negative effects on smelt and associated cultural ecosystem services, such as angling and bird watching. Climate change is likely to exacerbate current problems in the future although its effects on the ecology and hydro-morphology of the Tidal Elbe are currently not pronounced. Due to conflicting interests and associated power imbalances between the actors, solutions to the problems are politically divisive and therefore difficult to find.</p>