Reduce existing stressors to salmon populations. Existing stressors to salmon populations include habitat loss, fragmentation, and degradation; water of insufficient quantity and quality; alteration of historical disturbance regimes (e.g., flood regime, sediment regime); and historical overharvest. Cumulatively, these stressors have caused significant declines in salmon populations and reduced the resilience of salmon to future disturbances, including climate change. It is widely recognized that reducing existing stressors (e.g., preventing and reversing habitat destruction, replacing undersized culverts and other barriers to migration, preventing pollution, restoring instream flows) is necessary for the recovery of Pacific salmon.