The future of fish passage science, engineering, and practice

TLDR

Fishway science, once engineering‑centric, now spans biology, ecology, physiology, socioeconomics, and complex modelling, yet fundamental ecological knowledge for effective passage remains largely unknown, especially in biodiversity hotspots. The review calls for adaptive management, community‑scale passage, selective fishways to curb invasive species, and enhanced international collaboration, training, and regional expertise to design efficient fishways with minimal delays and impacts. The authors convened 17 experts across five research fields and five continents to identify knowledge gaps and propose a roadmap for research priorities and technical developments. They identified key knowledge gaps and outlined a roadmap for future research priorities and technical developments in fish passage science.

Abstract

Much effort has been devoted to developing, constructing and refining fish passage facilities to enable target species to pass barriers on fluvial systems, and yet, fishway science, engineering and practice remain imperfect. In this review, 17 experts from different fish passage research fields (i.e., biology, ecology, physiology, ecohydraulics, engineering) and from different continents (i.e., North and South America, Europe, Africa, Australia) identified knowledge gaps and provided a roadmap for research priorities and technical developments. Once dominated by an engineering-focused approach, fishway science today involves a wide range of disciplines from fish behaviour to socioeconomics to complex modelling of passage prioritization options in river networks. River barrier impacts on fish migration and dispersal are currently better understood than historically, but basic ecological knowledge underpinning the need for effective fish passage in many regions of the world, including in biodiversity hotspots (e.g., equatorial Africa, South-East Asia), remains largely unknown. Designing efficient fishways, with minimal passage delay and post-passage impacts, requires adaptive management and continued innovation. While the use of fishways in river restoration demands a transition towards fish passage at the community scale, advances in selective fishways are also needed to manage invasive fish colonization. Because of the erroneous view in some literature and communities of practice that fish passage is largely a proven technology, improved international collaboration, information sharing, method standardization and multidisciplinary training are needed. Further development of regional expertise is needed in South America, Asia and Africa where hydropower dams are currently being planned and constructed