Sockeye salmon over Bonneville Dam on the Columbia River. Lower temperatures in 2008 North Pacific waters brought in fatter plankton, which, along with greater outflows of Columbia River water, fed the resurgent populations. Proposed legislative efforts, such as the Northern Rockies Ecosystem Protection Act, are attempting to protect the headwaters of the sockeye salmon by preventing industrial development in roadless areas. Record numbers of a once-waning population of sockeye salmon have been returning to the Northwest's Columbia Basin (as of June 2012), with thousands more crossing the river's dams in a single day than the total numbers seen in some previous years.
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