Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 21 - 300
Comments: Jacobus et al. (2006) reared specimens collected from the Vermilion River in Sanders Co., Montana; and the McKenzie River in Oregon. It was recently confirmed in Washington in the Wenatchee River, Chelan Co.; North Fork Toats Coulee Creek, Okanogan Co.; Deadman Creek, Spokane Co.; and Thompson Creek, Whatcom Co., Washington (McCafferty and Meyer, 2007). In Oregon, it occurs in Benton, Clackamas, Douglas, Jefferson, Grant, Lane, Lincoln, and Linn Cos. (Meyer and McCafferty, 2007). In Idaho, it has been reported from the Snake River drainage in Myers Creek (Idaho Co.) within the Nez Pearce National Forest and across the Snake River in Oregon. In Montana it has been reported from 30 sites on ~20 streams in 7 counties: Beaverhead, Deerlodge, Missoula, Mienral, Granite, Powell and Sanders Cos. (Stagliano et al., 2007). Hogue and Hawkins (2008) summarized distribution to date as California (Alpine Co.: Caples Creek; El Dorado Co.: Alder Creek, South Fork American River; Frenso Co.: Kaiser Creek; Siskiyou Co.: Cecil Creek, Irving Creek, Plummer Creek, Upper Sacramento River; Tehama Co.: Deer Creek; Trinity Co.: Mule Creek; Tulare Co.: Freeman Creek, Peppermint Creek; Tuolumne Co.: Deadman Creek), Idaho (Boise Co.: Granite Creek; Bonner Co.: Lamb Creek; Clearwater Co.: Elk Creek, Johnny Creek; Elmore Co.: Shake Creek, Trinity Creek; Idaho Co.: Bargamin Creek, Big River, Meadow River, South Fork White Bird Creek, Twentymile Creek; Shoshone Co.: Bird Creek, Emerson Creek; Valley Co.: Trapper Creek), Montana (Deer Lodge Co.: Lamarche Creek, Warm Springs Creek; Granite Co.: Ranch Creek, Stony Creek; Powell Co.: Dempsey Creek, Racetrack Creek, Rock Creek), Oregon (Douglas Co.: Little River; Grant Co.: South Fork Desoation Creek; Jackson Co.: Ashland Creek), and Washington (Columbia Co.: Tucannon River). Jacobus and McCafferty (2008) cite occurrences in the Vermillion River, Sanders Co., Montana. In California, it occurs in Alpine (Caples Creek), El Dorado (Alder Creek; South Fork American River), Fresno (Kaiser Creek), Siskiyou (Cecil Creek; Irving Creek; Plummer Creek; Upper Sacramento River), Tehama (Deer Creek; Meadows Creek), tulare (Freeman Creek; Peppermint Creek), Trinity (Stoney Creek), and Tuolumne (Deadman Creek) Cos. (Meyer and McCafferty, 2008).