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The final stages of chinook development take place in one of two large, covered outdoor ponds or "raceways".
Each gravel-bottomed pond has a 32,000 cubic ft. capacity, and has a water throughflow of 4,500 gallons per minute (from the same gravity-fed water that supplies the rest of the hatchery).
Young chinook engage in normal feeding (supplied from mechanical feeders) and schooling behaviors.
Hatchlings live in the raceways for up to 11 months. When the reach 4-5" in length they generally become smolts.
"Smolting" is a series of physiological changes which occur in the young chinook, enabling their physiology to convert from that of a freshwater fish, to that of a saltwater fish. Smolting is induced by a combination of at least three factors including proper size, proper age and proper photo-period (i.e. length of daylight).
Once smolting begins, the fish are ready to be collected and released back into the South Fork of the Salmon River, where the smolting process will be completed as the journey downstream to the Pacific.