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Westslope Cutthroat Trout Movements through Restored Habitat and Coanda Diversions in the Nevada Spring Creek Complex, Blackfoot Basin, Montana

2014; Wiley; Volume: 143; Issue: 1 Linguagem: Inglês

10.1080/00028487.2013.839959

1548-8659

Ron Pierce, Craig. Podner, Tracy Wendt, Ron Shields, Kellie J. Carim,

Soil erosion and sediment transport

Abstract In the Blackfoot basin of western Montana, the recovery of migratory Westslope Cutthroat Trout Oncorhynchus clarkii lewisi requires landscape conservation as well as restoration of spawning tributaries. Westslope Cutthroat Trout are now increasing in the Blackfoot River and several streams, including Nevada Spring Creek, where natural channel, flow, and temperature regimes have reestablished aquatic habitat and migration corridors. To examine whether restoration has improved corridors for migration, we tracked the movements of 14 adult Westslope Cutthroat Trout from wintering areas in lower Nevada Creek (downstream of Nevada Spring Creek) to spawning and summering areas. Ten fish moved through Nevada Spring Creek upstream a median distance of 7.7 km (range, 7.6–16.9) to spawning sites at the headwaters of Wasson Creek through stream reaches where channels were reconstructed, instream flows enhanced, and grazing practices improved. Eight of the 10 fish that entered Wasson Creek spawned in a concentrated area upstream of two experimental diversion–fish screen structures located in the main channel of Wasson Creek. Prespawning movements of the remaining four radio‐tagged fish were much farther than those of Wasson Creek spawners (median, 51.8 km; range, 44.9–63.1). These four fish moved downstream through Nevada Creek into the Blackfoot River and then ascended upper Blackfoot River before entering two separate spawning tributaries. This telemetry study indicates that restoration can improve migration corridors which, in turn, promote the recovery of migratory Westslope Cutthroat Trout, and that spring‐influenced tributaries like Nevada Spring Creek provide important overwinter habitat for Westslope Cutthroat Trout that spawn and summer elsewhere in the basin.