We propose using an existing, longterm data set of sea urchin production, sea otter performance, and ecosystem state metrics from the last 30 years tobuild a spatially explicit sea otter population viability analysis (PVA) model, incorporating climate change effects. We propose a 3-pronged approach in year 1 of this project to evaluate (obj. 1) variability in sea urchin demographics over space and time to identify scaledependent patterns of variation in production using existing datasets, (obj. 2) define the direct effects of climate change and ocean acidification on sea urchin productivity through indepth literature review and contributions from experiments by collaborators, and (obj. 3) determine how effects of environmental change on prey resources will translate to upper trophic levels, influencing sea otter performance through a dynamic trophiccascade model. In year 2 of this project (obj. 4) we will incorporate results from year 1 into an Aleutian Island Sea Otter PVA model, providing a spatially resolved picture of how direct effects of climate change to sea urchins will impact recovery of the threatened SW stock of sea otters. Each objective will produce data products and GIS layers, made publicly available, which will forecast the potential recovery outcome for sea otters, and the nearshore ecosystem in the face of multiple environmental stressors.
