Climate Impacts to Salmon of the Pacific Northwest
We study how climate affects Pacific salmon and steelhead throughout their entire life cycle.
What We Do
Our research quantifies how climate shapes salmon habitat and interacts with human influences in the Pacific Northwest. We study how climate affects salmon and steelhead throughout their life cycle and how human influences, such as dams and fisheries, affect fish during their journey from rivers to the ocean and back again.
A warming climate is already altering oceans, rivers, and streams. These changes will increasingly affect Pacific salmon and steelhead in various ways at different points in their life cycle.
Impacts to freshwater life stages
Climate affects both the quantity and accessibility of cold-water habitat suitable for salmon in the freshwater stages as well as human demand for these same freshwater resources.
Climate also affects the magnitude of water available from rain or melted snow. High spring flows help smolts migrate over distances up to 1,400 km through the Columbia and Snake Rivers to reach the ocean. Changes in stream temperature and flow alter fish development, activity, growth, migration timing, and survival.
Climate effects in one life stage often carry over into subsequent stages. Accounting for cumulative effects on salmon is especially challenging and important, given their complex life history and migration behavior.
We study stage-specific processes to gain insight into climate effects and combine those insights to consider cumulative effects using life cycle models. These models help to quantify the full impact of climate and to evaluate mitigation efforts.
In the ocean, climate influences productivity at the base of the food web, as well as the abundance and composition of species that interact with salmon. Salmon are affected by a wide range of species, from plankton to anchovy, seabirds, whales, and sea lions.
The entire ocean ecosystem is susceptible to climate effects such as acidification. For Pacific salmon in the ocean life stages, we are building ecosystem models to help us understand marine climate impacts and explore management options that will support recovery.
Salmon response to the environment
In the Ecosystem Analysis Program, we develop technologies to collect data by tagging individual fish and building state-of-the-art detection systems. Detection data is used to study Pacific salmon behavior, migration timing, and survival.
We combine specific information on salmon behavior with important environmental data, such as stream temperature. These data are used to model survival during individual life stages, and the models help to inform management on particular issues, such as fisheries, hydropower operations, and habitat restoration.
Our analyses have revealed that over the past century, wild sockeye salmon shifted their migration timing to an earlier seasonal period. This shift in migration timing is likely an evolutionary response to climate change
Our studies also indicate that adaptive behavior (known as behavioral plasticity) is not expected to save Snake River sockeye without additional adaptation in the future. With ongoing climate change, this species is at a very high risk of losing its anadromous (migratory) life history.
We are also focusing on new work to better understand species interactions in the ocean. The marine environment has historically driven most coast-wide fluctuation in salmon populations.
Life cycle modeling
Management of endangered species relies on assessing population viability. Because of the complexity of salmon life histories, detailed life cycle models are needed to assess extinction risk and compare alternative management strategies.
Our models also inform environmental impact statements and biological opinions, which are used to determine whether federal actions put salmon in jeopardy of extinction.
Climate vulnerability of Pacific salmon
To understand which populations of salmon and steelhead are most vulnerable to climate change, we assess the relative exposure and sensitivity of population groups as they are listed under the Endangered Species Act (known as Evolutionarily Significant Units) to changing freshwater and ocean conditions. Managers can use this information to prioritize resources for climate mitigation actions.
Annual reviews of the literature on salmon response to climate
Each year, we monitor new scientific literature related to climate change impacts on salmon world-wide. We select and synthesize these publications for annual reviews that support adaptive management in the Columbia River Basin.
We develop online resources that support climate teams to share our findings and coordinate our research with other scientists across NOAA, the West Coast Region(IEA, Climate Toolkit), and other agencies and non-governmental research groups in the U.S. and Canada.