Pacific salmon are a valuable food and cultural resource in the Columbia River Basin, but their survival is threatened due to various drivers.  Particularly, climate change causes changes in water temperatures and flows, and multiple dams that provide navigation, flood control, and hydropower production also act as physical barriers to migration.  As salmon are part of this complex system of natural variability and competing human objectives, it is critical to understand drivers and timescales associated with migration dynamics.

In a recently published study by Goodwell and Campbell (CU Denver CVEN, MS 2020), we use information theory-based measures, which characterize uncertainty and reductions in uncertainty, to detect dependencies between salmon counts, water temperatures, flow rates, and other environmental variables.  We find key differences between fall and spring spawning runs that indicate how processes vary between seasons, and consider both individual and joint drivers of salmon migration timing.  At a longer timescale, we detect annual drivers of salmon abundances that include water temperatures and oceanic conditions.  This study introduces a suite of metrics with which to characterize life cycle drivers and feedbacks related to salmon, but could be applied to study influences on other species.

You can find the full article at this link: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0269193