Extinct Pacific Salmon Populations in the USA

Population Extinctions

Scientists estimate nearly 1400 genetically-isolated Pacific salmon populations once spawned from California to southern British Columbia.

Due to dam building and other alterations of lakes and rivers, 406 or 29 percent of the salmon populations have become extinct in the last 240 years.

Number of populations of each Pacific salmon species that are extinct or still surviving in California, Nevada, Oregon, Washington, Idaho and southern British Columbia.
Common Name Scientific Name Extinct Surviving
Steelhead Oncorhynchus mykiss 131 436
Chinook Oncorhynchus tshawytscha 159 237
Sockeye Oncorhynchus nerka 34 38
Coho Oncorhynchus kisutch 50 135
Chum Oncorhynchus keta 23 89
Pink Oncorhynchus gorbuscha 9 42

Regional Losses

In many cases, salmon have retreated from an entire region. Out of 13 ecological regions where wild salmon spawn from California to Idaho in the western United States, nine have lost one or more species of salmon since 1770.

Regional losses of native salmon species in contiguous western US.
Salmon Species Gone From
Steelhead Upper Snake River Columbia River headwaters
Chinook Southern California Northern coastal California Upper Snake River Columbia River headwaters
Sockeye Upper Snake River Mid Columbia River Columbia River headwaters
Coho Southern California Lower Snake River California Central Valley Mid Columbia River Upper Columbia River
Chum Northern coastal California California Central Valley Mid Columbia River
Pink Northern coastal California California Central Valley Klamath Mountains Province

Richard G. Gustafson, Robin S. Waples, James M. Myers, Laurie A. Weitkamp, Gregory J. Bryant, Orlay W. Johnson and Jeffrey J. Hard. 2007. Pacific Salmon Extinctions: Quantifying Lost and Remaining Diversity. Conservation Biology. 21(4): 1009-1020.

Back to Top
Science Articles