Fishway evaluations for better bioengineering: An integrative approach

Effective fishway design requires extensive integration of biological and hydraulic data. Many relevant biological parameters remain poorly characterized, however, and the lack of adequate biological data has long been recognized as a central weakness in fish passage technology. This is of particular concern given the growing recognition of the importance of passing a broad diversity of species. Part of the reason for this weakness is the difficulty of identifying relevant biological, hydraulic, and other physical parameters. We propose that by both exploring questions suggested by current knowledge, and also by increasing the frequency and refining the methods with which fishways are evaluated, two results can be achieved: our understanding of design effectiveness can be improved, and research questions can be prioritized through adaptive management. We describe a framework and rationale for fishway evaluations that identifies several promising avenues of research. Understanding correlates of passage performance is increasingly important as fish passage needs expand on a global scale.