Ecosystem modeling is being used to examine how bottom-up processes, driven largely by circulation patterns, relate to spatiotemporal differences in the abundance of lower and middle trophic level species. Ecosystem modeling also provides the framework for examining top-down processes and for examining the effects of various factors simultaneously influencing juvenile (and resident) salmon survival: understanding which factors are more significant, whether they have synergistic or compounding effects, how factors interrelate and which factors are proximate/direct vs. root/fundamental causes of mortality. Given the diversity and complexity of bottom-up and top-down forces that interactively influence the Salish Sea, a spatiotemporal ecosystem model is of great potential value, particularly an “end-to-end” ecosystem model that can integrate a broad range of oceanographic, biological, and social drivers, currencies, and scales. Contemporary models also help us develop ecosystem monitoring programs and test various management strategies. The specific questions examined include:
- How do short- and long-term changes in circulation and water chemistry affect the salmon, steelhead (and, other relevant species) in the Salish Sea?
- How sensitive are bottom-up processes to the effects of human activities in the Salish Sea, relative to natural variability?
U.S. Investigators: Raphael Girardin (NOAA), Chris Harvey (NOAA), Isaac Kaplan (NOAA), and collaboration with Parker MacCready (U. Washington)
- Develop a Puget Sound End-To-End, Spatiotemporal Model with Atlantis Software.
Researchers are working to create an ecosystem model that will serve as a tool for management of marine resources and ecosystem services in the Salish Sea, with particular focus on Pacific salmon. The model is built within the Atlantis framework, and simulates physical and chemical processes (water circulation, temperature and salinity, nutrient cycling), ecological processes (population dynamics, food web dynamics, migration, species-habitat interactions), and human systems (fishing, habitat, alteration, nutrient inputs, population growth) in 3-dimensional space. This modeling effort is being undertaken concurrently with a Strait of Georgia end-to-end, spatiotemporal modelling study led by Dr. Villy Christensen.
Using the Atlantis model, researchers can investigate which ecosystem processes have the greatest effects on juvenile salmon survival and evaluate simulated management scenarios to determine strategies that improve survival.