• dams;
  • Europe;
  • flow regulation;
  • North America;
  • Salmo salar ;
  • Salmo trutta

Abstract  Salmonid fishes have complex life cycles involving major changes in habitat requirements at different stages in their life history. Effects of changes in flow and flow regime on salmonids are therefore highly stage-specific. Successful management requires consideration of stage-specific influences and integration of these effects over the entire life history to predict ultimate impacts on abundance and population viability. The state of science regarding stage-specific influences of flow regime on juvenile salmonids and their habitats, referring specifically to fundamental attributes of natural regimes and to characteristic alterations of these regimes associated with water management, is reviewed. It appears that a key consideration in integrating the stage-specific impacts of flow is the extent to which flow-related losses or gains early in ontogeny can be compensated by increased growth or survival later in juvenile life history. Further, fundamental interactions between flow and water temperature must be incorporated into the robust models ultimately required for science-based management. In the absence of such models and data, the current state of science may be sufficient to target specific aspects of flow regimes that are critical to multiple life-history stages, which can then serve as a basis for interim flow prescriptions and subsequent adaptive management.