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Bull Trout Trends and Abundance*

(DRAFT)

Upper Snake Recovery Unit

Malheur Core AreaArrowrock Core AreaAnderson Ranch Core AreaLucky Peak Core AreaUpper South Fork Core AreaDeadwood River Core AreaMiddle Fork Payette River Core AreaNorth Fork Payette River Core AreaSquaw Creek Core AreaWeiser River Core AreaLitte Lost River Core AreaUpper Salmon River Core AreaPahsimeroi River Core AreaLake Creek Core AreaLemhi River Core AreaMiddle Salmon River-Panter Core AreaOpal Lake Core AreaMiddle Fork Salmon River Core AreaMiddle Salmon River - Chamberlain Core AreaSouth Fork Salmon River Core AreaLittle-Lower Salmon River Core Area Abundance: 1,150 - 4,850
Trend: Declining

Historic and current activities have led to conditions that are limiting bull trout abundance and productivity in the Upper Snake River Recovery Unit. Activities such as construction of impassable dams/culverts/diversions, land-use management, road construction/maintenance, and past fisheries management actions have affected the quality and quantity of riparian habitat and aquatic conditions.

Throughout the recovery unit numerous dams/culverts/diversions prevent bull trout passage, fragment habitat and population, and degrade water quality and quantity.

Historic and present land-use practices (i.e., forestry, grazing, agriculture, and mining) have degraded riparian and aquatic resources. Habitat degradation (riparian and in-stream) and impaired water quality/quantity are limiting bull trout abundance and productivity.

Construction and maintenance of road networks for forestry activities and general transportation have degraded habitat and water quality/quantity. Examples of some impacts associated with the transportation networks in the Upper Snake River Recovery Unit include increased sediment loading, altered runoff patterns, and restriction of normal stream channel movements.

Effects from past fishery management practices (i.e., non-native brook trout releases) continue to limit bull trout abundance and productivity. Brook trout present an on-going threat to bull trout through hybridization and possible competition for resources, as well as potential predation.


*The abundance and trend estimates represents summations of the information provided in the USFWS 5-Year Review. For a comprehensive review of the estimated abundance and trends, please refer to U.S. Fish and Wildlife Service. 2008. Bull Trout (Salvelinus confluentus) 5-Year Review: Summary and Evaluation. U.S. Fish and Wildlife Service. Portland, OR. 55 pp.

For a comprehensive review of the limiting factors affecting bull trout in this recovery unit, please refer to:
http://www.fws.gov/pacific/bulltrout/RP/Chapter_17%20Salmon.pdf
http://www.fws.gov/pacific/bulltrout/RP/Chapter_14%20Malheur.pdf
http://www.fws.gov/pacific/bulltrout/RP/Chapter_18%20Southwest%20Idaho.pdf
http://www.fws.gov/pacific/bulltrout/RP/Chapter_19%20Little%20Lost.pdf

Adapted from:

U.S. Fish and Wildlife Service. 2002. Chapter 17, Salmon River Recovery Unit, Idaho. 194 p. In: U.S. Fish and Wildlife Service. Bull Trout (Salvelinus confluentus) Draft Recovery Plan. Portland, OR.

U.S. Fish and Wildlife Service. 2002. Chapter 14, Malheur Recovery Unit, Oregon. 71 p. In: U.S. Fish and Wildlife Service. Bull Trout (Salvelinus confluentus) Draft Recovery Plan. Portland, OR.

U.S. Fish and Wildlife Service. 2002. Chapter 18, Southwest Idaho Recovery Unit, Idaho. 110 p. In: U.S. Fish and Wildlife Service. Bull Trout (Salvelinus confluentus) Draft Recovery Plan. Portland, OR.

U.S. Fish and Wildlife Service. 2002. Chapter 19, Little Lost River Recovery Unit, Idaho. 122 p. In: U.S. Fish and Wildlife Service. Bull Trout (Salvelinus confluentus) Draft Recovery Plan. Portland, OR.