The Feather River Fish Hatchery is run by the California Department of Fish and Game, and funded by the Department of Water Resources and the State Water Contractors, as part of the State Water Project.
Chinook salmon (Oncorhynchus tshawytscha) migrate by entering the Sacramento River from the Pacific Ocean, and then turning into the Feather River, the place of their birth. During this time, salmon don't eat, relying instead on their fat reserves for energy to propel themselves for the remainder of their journey in fresh water.
Once they reach the Feather River Fish Hatchery, the salmon enter a series of gates and fish ladders. The ladders are not unlike some of the natural river cascades they would encounter, if they were continuing upstream to complete their lifecycle.
The ladder guides them into the spawning building, where they'll complete their life cycle and contribute to the next generation of Feather River Chinook salmon.
The fish are herded into a hydraulic lift. Those fish that are ready to spawn are quickly killed, sorted by sex, and sent down a two-sided table. It's on this table that the female's abdomen is opened up and the eggs are placed into a bucket. A male's abdomen is then squeezed over the eggs to release milt (sperm) to fertilize the eggs. Two females and two males are used per bucket.
From here, the eggs are carefully washed and placed in incubator trays, where a constant flow of fresh Feather River water flows through the eggs at all times. This provides a safe environment for their development, while protecting the eggs from the natural hazards of predation and flood. After several days, each tray is sorted and the unfertilized eggs are hand-picked and removed. Unfertilized eggs can be easily identified because they turn white. If left in the tray with the fertilized eggs, they will quickly collect mold and contaminate the fertilized eggs.
Counts are also done to determine the percentage of fertilized eggs versus unfertilized eggs. This ratio measures fecundity. An "eyed-egg" usually forms in 25 days and can be easily identified by the eyes within each egg. It only takes 45 days for a Chinook salmon to grow from a fertilized egg to an alevin (sac fry).
Meanwhile, as with those salmon spawning in the river, the parents die and become food. The Department of Fish and Game, as do other States throughout the west, provides their salmon carcasses to worthy causes. In this case, these fish are on their way to a local food bank.