A critical component of re-establishing a population of naturally reproducing and self-sustaining spring-run Chinook salmon in the San Joaquin River is by developing a juvenile population for release into the river.

Since spring-run Chinook were extripated from the river in the early 1950s following the construction of Friant Dam, the SJRRP has been working to create a new population of this species in the river.

Since no fish are available to spawn naturally, spring-run Chinook are being spawned in hatcheries using stock from other rivers in California that still have the species. The expectation is that over time, the San Joaquin River will have its own unique genetic stock of spring-run Chinook salmon.

To achieve that desired result, a process to mimic the natural spawning that occurs in the wild takes place at the Interim Salmon Conservation and Research Facility and the Salmon Incubation and Research Facility, located below Friant Dam by the California Department of Fish and Wildlife. Here, eggs are harvested from full-grown adult female spring-run, fertilized with male donors, incubated, hatched and raised in captivity until they are released as juveniles.

The Program reached a milestone in 2017 when for only the second time in history (the first in 2016), a release of genetic broodstock juvenile spring-run Chinook salmon unique to the San Joaquin River. A small number of these fish had transmitters surgically implanted in order to allow scientists to track their movements, learn about survival rates, and determine other scientific information that will help to establish a stable population.