Salmon River, Idaho

William Clark drew this “white salmon” in his journal in 1806. The effects of climate change have degraded the habitat of the Salmon River, where the expedition once caught 500 similar fish in one day.

Oregon Historical Society

Downstream from here, on August 22, 1805, Clark and a small party explored ahead along the Salmon River. They came upon some Shoshone families drying fish and berries. Clark’s party tried spearing fish in the river but only caught one small salmon. Back at the main camp, Lewis’s group had better luck, using a brush drag to pull more than 500 fish from the river.26

Climate change and extreme weather events have altered Salmon River conditions. In July 2015, a record heatwave and low snowpack created water temperatures that killed most of the naturally migrating adult sockeye salmon in the river. Average water temperatures are expected to further rise, reducing the river flow by up to half and threatening the endangered salmon population.27

Citations:
26 NPS, “Salmon River,” Lewis & Clark National Historic Trail, January 12, 2021, https://www.nps.gov/articles/000/salmon-river.htm; Meriwether Lewis, August 22, 1805 entry, in Gary E. Moulton, Journals of the Lewis and Clark Expedition, https://lewisandclarkjournals.unl.edu/item/lc.jrn.1805-08-22#n21082210.
27 U.S. Global Change Research Program, “Chapter 27: Northwest,” in Fifth National Climate Assessment, edited by A. R. Crimmins, et al. (Washington, DC: U.S. Global Change Research Program, 2023), https://nca2023.globalchange.gov/chapter/27/ (see Box 27.1 Snake River Sockeye Salmon).

Climate Change:Lewis and Clark Trail