Do Habitat Actions Affect Juvenile Survival? An Information‐Theoretic Approach Applied to Endangered Snake River Chinook Salmon

We used 11 years of parr‐to‐smolt survival estimates from 33 Snake River sites to demonstrate that despite a number of confounding factors higher numbers of past habitat remediation or enhancement actions are associated with higher parr‐to‐smolt survival of endangered wild Snake River spring−summer (stream‐type) Chinook salmon Oncorhynchus tshawytscha . Information‐theoretic weights were applied to help distinguish between statistical models based on their relative plausibility. In the models with the highest estimated weights, actions taken to improve fish habitat showed a positive association with increased parr‐to‐smolt survival. However, because the actions were not sited randomly on the landscape, and because the actions may also have influenced other potentially important covariates, it is difficult to separate habitat action effects from effects due to other important factors.