The Willow-Whitehorse Management Unit (WWMU) is within the Alvord Lake hydrologic unit (HUC 17120009). LCT are native to waters that flow into the Coyote Lake subbasin, with the Alvord cutthroat trout, a putatively extinct subspecies, existing within the remainder of this hydrologic unit (waters that historically flowed into Alvord Lake). This unit represents the northernmost portion of LCT’s historical range. Currently, three potential LCT recovery populations exist in this unit, within separate but neighboring stream systems, Antelope, Willow, and Whitehorse Creeks. The Willow and Whitehorse Creek populations require only a minimal amount of management and continue to meet WWMU objectives 3 and 4. Antelope Creek is likely functionally extirpated at this time. In addition, several isolated LCT populations also exist in headwater streams in the Steens Mountains in the western portion of this unit but are technically outside of the historical range (Alvord Lake subbasin).

The updated objectives for LCT in the WWMU are:

WWMU 1) Remove threats (i.e., competition, predation, hybridization) associated with non-native trout species to allow for the formation and/or maintenance of WWMU LCT populations identified in WWMU objectives 3–5; and

WWMU 2) Ensure all habitats required to meet WWMU objectives 3–5 function ecologically. In some cases, this may require restoration and/or management changes; and

WWMU 3) Maintain the interconnected Whitehorse Creek recovery population; and

WWMU 4) Maintain the recovery population within Willow Creek; and

WWMU 5) Maintain existing, isolated populations and the out-of-historical-range populations in the Steens Mountains, and actively manage them (adopting guidance from the pending LCT Genetics Management Plan) to increase long-term persistence probabilities for use in augmenting Willow and Whitehorse Creek recovery populations as needed.