A salmon ecosystem conceptual foundation for estuary restoration

A cohesive recovery strategy for Pacific salmon populations requires a shared conceptual foundation to coordinate management actions across jurisdictions and interests. We examined an estuary restoration program as a case study of a life history ecosystem framework proposed for Columbia River salmon conservation in 1999. The estuary program lacks an explicit framework to account for cross-scale connections to other salmon life stages. We propose the following conceptual foundation, composed of three guiding principles: (1) the estuary is a subsystem of a complex natural-cultural system connected by salmon life cycles; (2) a dynamic mosaic of estuarine habitats supports growth, ontogenetic development, and life history variations of salmon throughout the basin; and (3) physical and biological processes beyond the estuary limit opportunities for salmon life history expression within it. These principles require additional estuary performance indicators to coordinate water and fishery management programs and to adapt estuary restoration actions to a changing climate.