Smallmouth Bass (Micropterys dolomieu) Removal in the Middle Green River, Utah, 2004-2006

摘要

The Upper Colorado River Endangered Fish Recovery Program has determined that control of nonnative fish in the upper Colorado River basin is essential to the recovery of the four endangered fish species: Colorado pikeminnow (Ptychocheilus lucius), razorback sucker (Xyrauchen texanus), humpback chub (Gila cypha), and bonytail (Gila elegans). This determination has been documented specifically for Colorado pikeminnow, razorback sucker, and bonytail in nursery habitats and in the mainstem middle Green River in Section 4.3.2 of each species Recovery Goals (U.S. Fish and Wildlife Service (USFWS), 2002) document. Smallmouth bass (Micropterus dolomieu) abundance has dramatically increased in the Green River since 2000. This increase resulted in a recommendation from the December 2003 Nonnative Fish Control Workshop (Grand Junction, CO) to attempt control of this species in the Green River. Three years of removal, from 2004-2006 and annual Nonnative Fish Control Workshops have added to the knowledge base of the effort required to successfully remove smallmouth bass from the Green River. Experimental smallmouth bass removal efforts in the middle Green River began in 2004 and continued to 2006. Removal efforts began in Echo Park (RM 344) and continued to Swaseys Rapid (RM 132). This 212-mile reach of river was split into three different stretches and covered by three different agency groups. Each stretch of river was sampled for smallmouth bass using shoreline electrofishing. Smallmouth bass were captured, weighed, tagged, and released on the first pass of each year.