Meeting Abstract
We present a novel agent-based model of juvenile salmon migration through the complex and highly altered Sacramento-San Joaquin Delta in California. The role of water diversions, withdrawals, and flow course alterations on the movement and fate of aquatic organisms in terrestrial flows is still a nascent area of research. In the past, much effort has been expended on three distinct approaches: (i) understanding the locomotive behavior of aquatic organisms at small spatial and temporal scales until just beyond the ballistic range of hydrodynamically assisted movement, (ii) developing hydrodynamic models of water systems involving simple movement models to represent the dispersal of populations, and (iii) developing agent-based ecological models which phenomenologically regress environmental variables on biological responses. Here, we couple the local hydrodynamics within the water column to a random walk model of particles representing simulated salmon to which we ascribe behaviors based on observed migratory patterns in acoustically tagged fish. This is a new approach that bridges the divide between organism-scale movement physics, and population- and system-scale migration dynamics. We show that our mechanistic model captures observed trends in population metrics such as migration time, survival, route selection, and entrainment at water withdrawal facilities. We also discuss how to more accurately bridge organism-scale movement physics with observed migration patterns using more sophisticated correlated movement models.
