Summary / Abstract This data set contains information collected from hybrid (westslope cutthroat trout x rainbow trout) and rainbow trout captured by trapping and jet boat-based electrofishing during spring of 2016 in the upper Flathead River system. Fish were captured in an ongoing suppression effort to stem the upstream spread of hybridization.
Data Collection Methods Migrant traps were deployed in 2016 in three tributary streams of the Flathead River to capture upstream migrating trout (Abbot, Rabe, and Ivy). A migrant trap was deployed in Abbot Creek downstream of the barrier and about 75 m upstream of the confluence with the Mainstem Flathead River to capture hybrid and rainbow trout spawners. An additional trap was installed about 15 m above the confluence of Ivy Creek with the Mainstem. A third trap was placed in Rabe Creek about 100 m above the Mainstem confluence. Each trap was checked at least once per week and total length (mm), sexual maturity, and genetic samples (fin clips) were taken from all captured fish. Rainbow trout and hybrids were removed and transported to a community fishing pond (Pine Grove Pond) in Kalispell.
Spawning rainbow trout and hybrid fish were also captured near tributary mouths by electrofishing from an 18' jet boat rigged with fixed-boom anodes during 2016. The Coffelt M22 rectifying unit produced straight DC at 3 to 5 amperes. Effort was concentrated in the Mainstem Flathead river within 50 m of the mouths of Abbot, Rabe, Ivy, Third creeks, and Sekokini Springs. Fish were also collected using backpack electrofishing units within some tributaries. All rainbow trout and hybrids captured were treated identically to trap-caught fish.