Author(s): Martin A. Wilkes, Morwenna Mckenzie, J. Angus Webb
Linked Author(s): Martin Wilkes
Keywords: Fish passage, fishway design, hydropower, non-sport fish, southern hemisphere
Abstract: The development of hydropower and other infrastructure that disrupts river connectivity poses a serious threat to highly endemic and genetically distinct freshwater fish species in temperate parts of the Southern Hemisphere. Such locations have been neglected in previous reviews on fish passage. Fishways have long been constructed to mitigate the impacts of riverine barriers on fish, yet they have failed for all but the largest, strongest swimming taxa. This is a particular problem in the temperate south, where the majority of species are small-bodied with low swimming performance. Using the Eco Evidence method for rapid evidence synthesis, we undertook an assessment of evidence for effective fishway design focusing on species representative of the temperate south. Systematic literature searches resulted in 630 publications. Through a rigorous screening process, these were reduced to 46 publications containing 76 evidence items across 19 hypotheses relating to design criteria for upstream and downstream passage. Each evidence item was weighted according to the robustness of its study design. These weightings contributed towards the support or rejection of each hypothesis using well-established thresholds. We found an overwhelming lack of evidence for effective fishway design in the temperate south. Particular deficiencies were found with regard to the design of effective facilities for downstream passage. The attraction and entrance of upstream migrating fish into fishways is also relatively under-researched. Given the urgent need for effective fishways in the temperate south, these results justify an approach to fishway design based on a combination of empirical data and expert knowledge. In the meantime, significant resources should be assigned to improve the evidence base through high quality research. The particular deficiencies identified here could guide that research agenda
Year: 2017