We use population dynamic models to calculate the cumulative effects that influence Chinook salmon extinction risk. These statistical models integrate multiple climate-related impacts that affect salmon throughout their life cycle.
Known as life cycle models, these simulations rely on detailed studies of individual life stages and projections of future climates. They help quantify the potential impacts of climate change and specific proposed mitigation actions such as dam operations or habitat restoration changes. This information supports decisions on the risk imposed by federal actions through environmental impact statements under the National Environmental Policy Act and biological opinions under the Endangered Species Act.
Our models project that Snake River spring/summer Chinook salmon populations will decline dramatically in the coming decades. This decline is due primarily to rising sea surface temperatures and changes in river and stream temperatures and flows. Consistent with these projections, we have already seen record-low returns of salmon species across the West Coast in response to the marine heat wave of 2014-2016.
We projected the most dire effects for the marine life stage. Our current work focuses on the interspecific dynamics that affect marine survival. We build a set of conceptual, statistical, intermediate complexity, and ecosystem end-to-end models to fully capture our understanding of these relationships. The models explore how climate will alter the marine environment and management tools to mitigate these effects on salmon.