Winter-run Chinook salmon complete their life cycle across a diversity of habitat types (or habitat strata), which complicates attempts to understand how specific environmental stressors impact the population as a whole. In this study we constructed a life-cycle model for Sacramento River winter-run Chinook to evaluate potential management actions and project operations on their population dynamics. The model incorporates multiple life-history stages, including spawning, egg incubation, fry rearing, smolt migration/Delta passage, and ocean rearing. The investigation describes model functions and presents a sensitivity analysis to estimate fish-environmental factor relationships with strong effects on the winter-run Chinook population. Evaluation of potential management actions was demonstrated by perturbing flow, export volumes, and water temperature +/- 10%. The model represents a powerful analytical tool that can be used to assess how environmental changes, including those associated with climate change, or management interventions, for examples water-export management and salmon harvest, at one life stage affects subsequent life stages and the dynamics of the population as a whole. The model can be essential to establishing the magnitude and direction of management-action effects prior to implementation of a management agenda and to understand the consequences of large-scale environmental fluctuations.
Zeug SC, Bergman P, Cavallo B, Jones KS. 2012. Application of a life cycle simulation model to evaluate impacts of water management and conservation actions on an endangered population of Chinook Salmon. Environmental Modeling and Assessment 17:455-467.