River Damming Impacts on Fish Habitat and Associated Conservation Measures

River damming has brought great benefits to flood mitigation, energy and food production, and will continue to play a significant role in global energy supply, particularly in Asia, Africa, and South America. However, dams have extensively altered global river dynamics, including riverine connectivity, hydrological, thermal, sediment and solute regimes, and the channel morphology. These alterations have detrimental effects on the quality and quantity of fish habitat and associated impacts on aquatic life. Indeed, dams have been implicated in the decline of numerous fishes, emphasizing the need for effective conservation measures. Here, we present a global synthesis of critical issues concerning the impacts of river damming on physical fish habitats, with a particular focus on key fish species across continents. We also consider current fish conservation measures and their applicability in different contexts. Finally, we identify future research needs. The information presented herein will help support sustainable dam operation under the constraints of future climate change and human needs. River damming yields great social-economic benefits, but also causes significant eco-environmental impacts, particularly on fish. Dams block fish migration routes, alter hydrological and water temperature regimes, and modify channel morphology. These changes impact fish physical habitats and associated communities. Here, we synthesize the impacts of river damming on fish physical habitats, and review potential conservation measures that could be used to off-set or mitigate the impacts of dams on fish habitats, populations and communities. Dam construction alters river hydro-geomorphological conditions and hence influences fish habitat quality and quantityKnowledge of river hydrogeomorphology and reservoir properties can inform which conservation measures may benefit fish conservationLong-term monitoring is needed to understand causal effects and synergies with climate change