Spring-Run Salmon Reintroduction: Lessons Learned from 2 Years of Activities

Reintroduction of Chinook Salmon is a central element of the San Joaquin River Restoration Program.  The substantial construction and flow management elements being implemented under the Program require initial reintroduction activities to be initiated while the system is undergoing constant and significant change. Reintroduction actions are constrained by present habitat conditions and system connectivity, among many other issues.  Efforts have been made to increase survival and return rates of introduced stocks by providing acclimation and imprinting opportunities; however, this requires extensive handling of individuals and whether or not these actions provide more benefit than harm remains a concern.  Starting in 2014, initial release groups (~55,000 fish) have been introduced using low-technology approaches (e.g., 5-gallon pails) and held in temporary net pens for relatively short time periods.  Future returns will provide some insight into the success of these efforts.  Continued evaluation of stocking levels, acclimation and imprinting procedures, and associated survival and adult return estimates will be used to inform decisions regarding future stocking levels and implementation of reintroduction activities.