Baker River (Washington) year. The WDFW and others' models predicted a run size for Baker sockeye of 46,268 in 2015. Before Lower Baker Dam was built in 1925 the fish had free access to the river and natural (pre-dammed) Baker Lake. The annual sockeye run at that time was estimated to be approximately 20,000 fish. Artificial enhancement began in 1896 when the State of Washington constructed a hatchery on Baker Lake. This was the first establishment for the hatching of sockeye salmon. The hatchery closed in 1933. The construction of Upper Baker Dam in 1959 inundated the natural Baker Lake and surrounding valley,
Kokanee salmon of landlocked sockeye has occurred more than once with different kokanee populations, showing genetic differences between populations. Most evidence points to events that land-locked the lake-type sockeye (which spawns in streams and lakes, rather than tributaries like the sea-type sockeye, but is still anadromous and spends most of its adult life out at sea), which evolved into the non-anadromous form. Genetic evidence from kokanee in the Fraser River drainage and Columbia River drainage shows that ancestors of the kokanee came from the lake-type sockeye. The data also suggests that the kokanee may have evolved back into a lake-type anadromous form