Tributary Spawning by Endangered Colorado River Basin Fishes in the White River

The Green River system in the upper Colorado River basin supports populations of endangered Razorback Sucker Xyrauchen texanus and Colorado Pikeminnow Ptychocheilus lucius. Documented spawning areas for these species are few and occur mainly in the Green River main stem and the lower reach of the tributary Yampa River. Herein, we report spawning by both species in an additional Green River tributary, the White River. We documented Razorback Sucker and Colorado Pikeminnow larvae and early juveniles in a 20-km reach of the lower White River, Utah, in 2011. Movement of hatchery-produced Razorback Sucker adults into the White River and subsequent reproduction suggests that these fish use the system to complete important life history processes. Presence of spawning areas for two endangered fishes in the White River emphasizes the important role of tributaries for providing spawning and rearing habitat for native and endangered fishes.