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Bull Trout Trends and Abundance*


Swan Lake Core Area

Abundance: 1,000-2,500
Trend: Stable

In the Swan Lake Core Area, past land use activities, transportation networks, and previous fisheries management practices have resulted in conditions that are limiting bull trout abundance and productivity.

Forestry practices have impaired bull trout habitat throughout the core area. Legacy effects include increased sediment in streams, increased peak flows, hydrograph and thermal modifications, and loss of in-stream wood and channel stability. Logging roads have led to increased sediment loads, channelization, valley bottom restriction, and increased accessibility for anglers and poachers.

The legacy effects of old transportation systems have led to conditions that are limiting bull trout. Past activities resulted in channelization and meander cutoffs, passage barriers, sediment production, unstable slopes, improper maintenance, and high road densities.

Residential development and sprawl are threats to bull trout in this core area. Continued development will increase the demand for flood control, stream crossings, water diversion or withdrawal, and other stream channel alterations that are potentially harmful to bull trout.

Historic releases of non-native fish has led to competition and hybridization, which have reduced bull trout abundance and productivity. Expansion of non-native species populations is problematic since there are a limited number of acceptable methods to remove the fish. In addition, there is public opposition to controlling or eliminating non-native sport fisheries.

*The abundance and trend estimates are from 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 Core Area, please refer to:

Adapted From:
U.S. Fish and Wildlife Service. 2002. Chapter 3, Clark Fork River Recovery Unit, Montana, Idaho, and Washington. 285 p. U.S. Fish and Wildlife Service. Bull Trout (Salvelinus confluentus) Draft Recovery Plan. Portland, OR.