Freshwater Biodiversity Toolbox
Wildlife Passage – Provision of Passage at Dams and Hydropower Facilities
Habitat fragmentation is a major threat to aquatic ecosystems. Dams and hydropower act as barriers to wildlife, preventing fish from accessing key habitat that may be used for spawning or migration. Fish ladders, fish ways, and other passage infrastructure have been installed at dams as a way to provide habitat access and maintain population dynamics for targeted fish species. However, even with these structures in place, successful passage may not be possible due to the physical constraints and behaviour of certain fish species that prevent effective use of ladders or fish ways. Mortality during crossings is a key concern regarding the efficacy of these passage structures. The potential benefits, risks and mitigation options associated with different types of passage structures at dams and hydropower facilities are reviewed here.
Rating:
Most syntheses in this intervention scored poorly in CEESAT demonstrating limitations in the rigour and the transparency in which these reviews were conducted (i.e., no a-priori protocol, critical appraisal, or search strategy provided). Four syntheses scored Green in at least one CEESAT element mostly related to searching and data extraction methods. Wilkes et al. (2018) scored Gold for transparently reporting article screening, exclusion, and inclusion rates.
The majority of syntheses scored well in RASCAT demonstrating high applicability and relevancy to a Canadian freshwater context. Poor scores were only given in elements related to publication year and the ability to demonstrate consideration of implications, practical advice, or recommendations for decision-makers.
Photo credit: Kai3952