Bull trout (Salvelinus confluentus) are listed as a threatened species under the Endangered Species Act (ESA). Historically, bull trout occupied much of the available habitat in the central Idaho, but currently occupy less than half of their original range (Rieman et al. 1997). Migratory forms of bull trout have been restricted or lost, some populations are declining, and local extinctions have occurred across the species' range (Rieman et al. 1997).
While westslope cutthroat trout are not listed as threatened or endangered under ESA, they are still classified as a species of special concern by the Idaho Department of Fish and Game (IDFG), and as a sensitive species by the United States Forest Service (USFS) and Bureau of Land Management (BLM). Current westslope cutthroat trout distribution and abundance are restricted compared to historical conditions (Behnke, 1992). Many populations have been isolated due to habitat fragmentation from barriers such as dams, diversions, roads, and culverts (Behnke, 1992).
Westslope cutthroat in the Salmon River basin have been documented to exhibit fluvial and resident life histories (Bjornn and Mallett, 1964). Westslope cutthroat are spring tributary spawners with spawning commencing in April and May, depending on stream temperatures and elevations (Behnke, 1992).
The goal of this research project is to identify critical rearing, staging, and spawning areas used by fluvial trout populations in the upper Salmon River basin. This information is intended for use in further habitat protection and enhancement projects through the Upper Salmon Basin Watershed Project (USBWP) (formerly Lemhi Model Watershed Project).
Migratory information will also be critical for further identification and prioritization of future diversion screening projects throughout the basin. Information will also be used to increase awareness of the life history and habitat needs of these fish to the general public via the internet. This portion of the study would be similar to other projects such as the Bear Valley Cutthroat radiotag study, a cooperative project involving the Boise National Forest, the Ted Trueblood Chapter of Trout Unlimited, IDFG, and Garden Valley High School. A similar study called the Adopt-A-Trout project in Montana, involves the Montana Fish, Wildlife, and Parks (MFWP), the USFWS, the Blackfoot Challenge, and TU.
Radio telemetry will be used to determine the migration patterns of fluvial trout in the upper Salmon River basin. To obtain an accurate estimate of migration patterns, a minimum of 50 bull trout, 50 westslope cutthroat trout, and 50 resident redband/rainbow trout will be radio tagged and tracked throughout the basin. Fish will be collected through a combination of electrofishing and angling. Bull trout capture will occur in late-winter and early-spring, while cutthroat and redband trout capture will occur in the fall and early-winter. These collections will take place in the mainstem Salmon River. Additional summer collections may be necessary and will occur in tributaries with sufficient populations. Captured fish will be anaesthetized and measured (weight (g) and total length (TL mm)). Radio transmitters will be surgically inserted into the peritoneal cavity following the protocol described in Schmetterling (2001). Transmitters will be Lotek Engineering models MCFT-3BM and MCFT-3EM, weighing 7.7 and 8.9 grams, respectively, and will not exceed 2% of fish weight (Winter 1996). To reduce surgery time and risk of infection, surgical staples will be used instead of sutures (Swanberg et al. 1999). Tagging location will be recorded using Global Position System (GPS) technology, as will subsequent observations of tagged fish.
Tracking
Stationary telemetry receivers will be placed at the mouths of the North Fork Salmon, Lemhi, Pahsimeroi, East Fork Salmon, and Yankee Fork Salmon Rivers. Utilizing a satellite uplink, the stationary receivers will allow for remote data retrieval, saving time and allowing for more focused tracking efforts. Upon the recognition of tagged fish entering these watersheds, their movement will be tracked and documented by a combination of ground and aerial tracking efforts. This will be accomplished by vehicle on those tributaries with roads and by fixed-wing aircraft in remote areas. Flights will occur on a bi-weekly basis and will coincide with increased movements of tagged fish seen at the stationary receivers established throughout the basin. Ground tracking will be conducted on either a weekly or bi-weekly basis from April to mid-December, depending on movements seen at the stationary receivers. The number of searches throughout the winter months will be determined as the project progresses and more information regarding migration and winter habitat use is obtained.
Data collected from radio tagged fluvial trout in the upper Salmon River basin will be mapped using Geographic Information System (GIS) to show the migration patterns and seasonal habitat use of these fish.
Study Area:
The upper Salmon River basin (Figure 1) lies within the central Idaho mountains, encompassing the upper reaches and headwaters of the Salmon River. The basin is approximately 1.6 million acres in size with 
elevations ranging between 5,000 and 11,000 feet, and includes approximately 155 miles of rivers and 5,711 miles of streams (USFS and BLM, 1998). Drainage area for the basin is approximately 2,425 square miles (USFS and BLM, 1998). Public land is predominant in the upper Salmon River basin (95%), with the majority under management by the USFS (69%). The BLM (24%) and the state of Idaho (2%) also manage public lands in the basin. Water quality throughout the basin is generally high, although degradation from sedimentation and high concentrations of nutrients and metals has occurred in some streams affected by improper road construction and location, past and present mining activities, and excessive or improper livestock grazing (USFS and BLM, 1998).
Conditions less favorable to the basin's native fish populations are common in all major watersheds except those dominated by wilderness and roadless areas. Therefore, the Middle Fork Salmon River, and the Salmon River and those tributaries downstream of the Middle Fork, will be excluded from this study. The study area will be the mainstem Salmon River from Panther Creek upstream to its headwaters near Stanley, ID. This will include the North Fork Salmon, Lemhi, Pahsimeroi, East Fork Salmon, and Yankee Fork Salmon Rivers.
Many (38%) of the subwatersheds within the Salmon River basin support strong populations of one or more native species of salmonids, including populations with large fluvial adults. The abundance of resident salmonid strongholds in the Salmon River basin is related to natural features, the abundance of relatively less developed and intact watersheds, and a high historic diversity of these fish within the basin (ICBEMP, 2000).
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Ted Trueblood Chapter of Trout Umlimited