Management of floodplain wetlands for endangered fish recovery in the middle Green River, Utah

Authors: David W Speas, Tildon Jones, Matthew Breen

Year: 2016 (xlviii)

Abstract

Spring peak releases from Flaming Gorge Dam in northeastern Utah are timed with emergence of razorback sucker Xyrauchen texanus larvae in the middle Green River. When combined with flows from the Yampa River, these peak releases provide larvae access to floodplain wetlands where they experience excellent potential for growth and survival. 2016 was the fifth consecutive year of implementation of these larval triggered flows, which have resulted in mean production of 479 wild-spawned young-of- year razorback sucker per year from Stewart Lake, a managed wetland near Jensen, Utah. Such production from a naturalized setting in the Green River is significant, and moreover the Stewart Lake experience has afforded researchers and managers insight into basic requirements for successful rearing of entrained razorback sucker larvae in floodplain wetlands. These requirements include the ability to control wetland water levels prior to, during and after the entrainment period, the ability to exclude non-native fish from rearing habitats, and the ability to harvest or provide access to the river for young-of-year fish. Opportunities are being explored to apply such measures to additional floodplain wetlands with the hope of increasing abundance of wild -spawned razorback sucker in the middle Green River.