New Genetic Methods Help Improve California’s Salmon

 
Sacramento California – The current drought, in combination with other long-term stressors, is threatening the survival of Sacramento River Chinook Salmon populations. In response, the Central Valley Project Improvement Act (CVPIA) has set a goal to double natural production of Chinook salmon in California Central Valley streams through restoration actions that involve both flow and non flow options. Yet, traditional sampling techniques have hindered the ability to quantify the benefits of these restoration actions, making it difficult to identify juveniles emerging within restored sites and those that benefited from flow management on a river-wide scale. Genetic methods can fill this information gap.
 
A new project has been launched that uses genetic mark-recapture and otolith microchemistry reconstruction tools to address these monitoring challenges. The project aims to test the extent to which restored spawning sites produce a greater number of juveniles than non-enhanced sites and how water operations influence the expression and survival of different outmigration strategies to adulthood. The results from this project will provide direct information on the success of restoration projects and guidance for flow management actions within the lower American River.
 
The genetics portion of the project conducted by Cramer Fish Sciences – Genidaqs involved the creation of a parental genotype database by genotyping all adult samples. Maximum likelihood methods were then used to assign or relate out-migrating juvenile genotypes to adult genotypes to determine spatially explicit recruitment patterns. This analysis documented recruitment from enhanced sites and provided a recruitment metric for both restored and unrestored sites.
 
Demonstrating a means to observe biological responses of the species targeted by restoration actions will provide guidance for management efforts, justifying investment in successful habitat restoration, and aid the long-term survival of Chinook Salmon in California’s Central Valley.
 
A publication for this project is in peer-review (2023).