Several species of salmon and steelhead are listed as endangered or threatened under the Endangered Species Act (ESA). Sockeye salmon (Oncorhynchus nerka) were listed as endangered in 1992, Chinook salmon ((Oncorhynchus tshawytscha) listed in 1992 (two runs of Chinook: spring/summer and fall), and steelhead ((Oncorhynchus mykiss) listed in 1998. All of these species are anadromous, meaning they are seagoing. Salmon and steelhead migrate from Idaho and other Northwest states through the Columbia River to the Pacific Ocean. They return to their native rivers and creeks to spawn and continue the cycle.
Many factors are to blame for the decline in salmon and steelhead populations. Some of the leading causes include:
- Change to outmigration timing
- Lack of access to historic habitat
- Habitat loss
- Other out of basin factors