Hatcheries are at the bottoms of dams ... fish born there return after a few years at sea and spawn, in the hatchery ... native fish return to the natural gravel beds below the dam somewhere, where they were spawned, to spawn again ... they some how smell their way home ... OSU is making sure the genes get distributed properly ...
Salmon are extinct above the dam ... unless there's a fish ladder or something ... Grand Coulee Dam notoriously doesn't have a ladder, no sea-run salmon in the upper reaches of the Columbia River ... just the landlocked strains ... and steelhead ...
A co-worker of mine stocked his creek with Chinook fry ... four years later he had ankle deep water with a mess of 30 lbs Springers ... too funny ...