Fish and chips: Conservation of freshwater fish populations through an integrative multi‐stakeholder approach

Abstract Rivers and their fish populations are under threat, prompting diverse conservation efforts. Effective freshwater conservation requires collaborative projects involving multiple stakeholders, including scientists, practitioners, and government agencies. Knowledge produced in these projects can be used to guide the application of evidence‐based conservation actions. We present a unique large‐scale and long‐term river and fish monitoring project at the alpine River Inn (Bavaria, Germany), where stakeholders from the private sector closely collaborate with science and governmental institutions. After a first phase of implementing and assessing habitat restoration, we recently employed passive integrated transponder (PIT) technology to tag and track several 10,000 fish from diverse species. A comprehensive monitoring infrastructure comprising 34 permanent and several temporary monitoring sites across 150 river kilometres now enables the detection of fish movement patterns across main parts of the River Inn catchment. This infrastructure also includes a citizen science initiative where anglers report captured fish in scanning stations. Stakeholder communication is institutionalized through the establishment of a project advisory board and an annual conference in which the major findings of the previous year are discussed and the future science and management agenda is set. Knowledge transfer also occurs through the translation of scientific findings into easy‐to‐follow guidelines, as well as through lectures and workshops. Synthesis and applications . This practitioner perspective offers a template case study for integrative river restoration and fish conservation campaigns. The successful application of information into conservation actions is based on active engagement of practitioners and easy‐to‐follow guidelines. The approach presented herein relies on the principles of knowledge co‐production and adaptive management, and is illustrated with examples that are transferable to other aquatic ecosystems.