The primary winter habitat for grayling in the Centennial Valley is in Upper Red Rock Lake in the Red Rock Lakes National Wildlife Refuge. High winter mortality of grayling in the lake during periods of low dissolved oxygen has been identified as the primary limiting factor for grayling in the Centennial Valley.
The USFWS and FWP are proposing to improve over-winter habitat for grayling in Upper Red Rock Lake, which will ensure long-term, self-sustaining persistence of grayling.
The proposed action, which includes installing a pipeline from Shambow Pond to Upper Red Rock Lake, would increase dissolved oxygen levels in deeper portions of the lake where grayling live during the winter. This will help improve grayling winter survival and maintain existing grayling genetic variation.
A draft environmental assessment was made available through the USFWS for a public review and comment period from Feb. 28 through March 28.
The decision notice can be found at bit.ly/3MYC7Xk. The environmental assessment and other supporting information can be found at fws.gov/refuge/red-rock-lakes/library.
