Biologists released fish into the river in Northwest Fresno on Wednesday. Scientists attached acoustic transmitters to track and collect data. They will use 12 receiver sites to see how quick the fish move up stream and see what areas they like to spawn in.
Scientists with the Natural Resources Defense Council say the program is all about long term restoration.
"It's an exciting project. Its more than just about salmon, it's more than just about the living river," Monty Schmitt said. "But it's also you know, a project that has benefits for a lot of people in the valley as well as the state of California."
Wednesday's release was just the beginning. Scientists hope to get the salmon population to about 40 thousand.