Grande Ronde / Imnaha (Major Population Group)

The Grande Ronde/Imnaha spring/summer Chinook MPG includes six extant (existing) Chinook Salmon populations in Oregon; Wenaha, Minam, Upper Grande Ronde, the Imnaha River, the Wallowa-Lostine rivers, and Catherine Creek. The Big Sheep Creek and Lookingglass Creek populations are considered functionally extirpated as a result of low abundance over many generations and extensive genetic influence of non-local hatchery origin spawners. Populations in the Grande Ronde/Imnaha spring/summer Chinook MPG were listed as ‘threatened’ under the Endangered Species Act (ESA) in 1992 and the listing was reaffirmed in 2005 (U.S. Office of the Federal Register 1992, 2005).

Oncorhynchus tshawytscha