WSP10531 - Laserfiche WebLink

Home Browse Search

10 Sediment and stream channel morphology in the Green River are maintained somewhat by spring runoff from the Vampa River (Tyus and Karp 1989). Sediment import into the Green River from the Vampa River contributes to the systems present sediment quasi-equilibrium (Lyons 1989). This sediment is important in creating backwaters and other important habitats for endangered fishes. The Green and Vampa Rivers are also interrelated biologically. Colorado squawfish migrate from the Green River to spawn in the Vampa River, the larval are then transported back to Green River nursery habitats. Movement of adult endangered fishes, between the Green and Vampa Rivers, was well documented by Tyus (1990), Tyus and Haines (1991), and others. ENDANGERED FISHES The importance of the Green River to rare and endangered fishes was established by the Colorado River Recovery Implementation Program (Recovery Program) and recognized by many biologists as noted in the recovery plans for each of the species. The Green River and its tributaries were listed as the highest priority for recovery of Colorado squawfish in the Colorado River 8asin in the recently revised Colorado Squawfish Recovery Plan (U.S. Fish and Wildlife Service 1991). The Green River in Desolation and Gray canyons and in Dinosaur National Monument (Dinosaur) is considered extremely important in the recovery of humpback chub in the Humpback Chub Recovery Plan (U.S. Fish and Wildlife Service 1990a). The Bony tail Chub Recovery Plan (U.S. Fish and Wildlife Service 1990b) indicates that one of the last known riverine concentrations of bony tail chub was in the Green River within Dinosaur National Monument. In addition, the Green River supports the largest known population of razorback sucker in their natural riverine habitat (Lanigan and Tyus 1989). The Recovery Program placed a high priority on habitat management in the Green and Vampa Rivers through protection of instream flows. Because of the importance of providing legal protection for instream flows, the Service considers, within the Section 7 process, the legal protection of flows essential to offsetting project impacts. - 1he consolidated biology report (Tyus and Karp 1991) summarizes the distribution, abundance, and habitat use for the endangered fishes. Much of the species biological information discussed below was extracted from that report. COLORADO SQUAWFISH General Status Historically, Colorado squawfish occurred in mainstream habitats of the Colorado River system. The species was found in the Colorado River from the Utah-Arizona border to the Sea of Cortez in Mexico, and the Salt and Gila Rivers of the lower Colorado River Basin. However, all lower basin populations are considered extirpated (Minckley 1973). In the upper Colorado