Using Life Cycle Models to Identify Monitoring Gaps for Central Valley Spring-Run Chinook Salmon

Life-cycle models (LCMs) provide a quantitative framework that allows evaluation of how management actions targeting specific life stages can have population-level effects on a species. LCMs are particularly useful for species such as salmon that are highly migratory and use multiple aquatic ecosystems throughout their life. LCMs are lacking for threatened Central Valley spring-run Chinook (Oncorhynchus tshawytscha; CVSC), so the authors developed a CVSC LCM to describe the dynamics of Mill, Deer, and Butte creek CVSC populations. The authors propose a series of monitoring recommendations—such as the development of an enhanced juvenile-tracking monitoring program, and the implementation of juvenile-trapping efficiency methodology combined with genetic identification tools—to help fill highlighted data gaps.