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The Endangered Fish The Green River downstream of Raming Gorge Dam is home to the largest known river populations of the endangered Colorado pikeminnow and razorback sucker found anywhere in the world. This section of river also supports imponant populations of humpback chub and contains critical habitat for the extremely rare bonytail which has recently been stocked in the Green and Yampa Rivers to supplement populations of that species. ~",,'f!)':,;-- ~ ~~~:-'"-',W->"-"",_,. ,-'-'~' r" _""-_.~_~~_' $:~'~~:' d_ c~............ /~ ::;- :'''1:''- --- -, ~_L ." ,_...-" ...;... -"~ ~:~.t .- 'b. .... '-..s.:;. ....ri~ .' - \ . . . .. Colorado pikeminnow. CaIJed while salmon and Colorado salmon by early seulers, these fish were once abundant in the Colorado River and most of its tributaries. It is believed thai lhese fish at one time Ihoed .sO or more years. grew 38 inches long. and weighed up 10 25 pounds. native species of the Colorado River Basin. The Green River below flaming Gorge Dam. and particularly downstream of the largely free- flowing Yampa River. is important for endangered species because of its relatively unregulated nature and the fact that important habilats still occur there. Row recommendations for the Green River largely depend on using releases from Raming Gorge Dam 10 supplement flows in the Yampa Ri ver to mimic a more natural flow regime below Ihe confluence of the rivers. Under the Endangered Species Act, designated critical habitat for these fish species includes the Green River from its confluence '-'"ith the Yampa Riverdownstream to Lake Powell below the Colorado River confluence. The operation of flaming Gorge Dam is closely linked to recovery efforts for the endangered fishes in the Green River and is a critical element of me Recovery lmplememation Program for Endangered Fish Species in the Upper Colorado River Basin (Recovery Program). The link between me Recover)' Program and Raming Gorge Dam is important because the Reco~'ery Program has a dual mission-that of recovering the endangered fish species while also allowing for future water development for human use. The Recovery Program is one of the oldest basinwide recovery efforts and exemplifies successful cooperation among diverse stakeholders to recover endangered species while allowing me states to develop their Colorado River Compact entitlements. Since its inception in 1988. the Recover)' Program has allowed me Bureau of Reclamation and other agencies to successfully complete Endangered Species Act compliance on some 600 w8ter projects covering 618.000 acre- feet of new water developmeOl in Utah. Wyoming. and Colorado. Although the Green River above the Yampa River has not been designaled as critical habitat. this section of river is also inhabited by Colorado pikeminnow and razorback sucker. Recent research has shown that the Colorado pikeminnow is seasonally abundant in the Green River in Lodore Canyon and may occur as far upstream as Brown's Park on me Green River. The Colorado pikeminnow, razorback sucker. humpback chub. and bon)tail are unique to me Green and Colorado River systems. These fishes are adapted to a natural flow regime that consisted of a system of fluctuating seasonal and annual flows influenced by wet. average, and dry climatic periods that occurred prior to me construction of large-scale water projects. However, the very traits mal made them so successful in a historically variable environment have contributed to their decline in the more stable and regulated river environment that now occurs in much of the Colorado River system. The altered habitats mat occur as a result of dam construction are often more suitable for introduced. non- native fishes. some of which have flourished and now compete with and prey on the - , ,...<> .> ",' '..', ) , , -~ , ...... ,., <..~ .-.-......:;.... .".- . - . :~f",,~~~~e~.~.; .~. ~\ J .' "~ ' '\.---":.' \ .,' ~ " ~..;~. ' ....~ . _~' '-IfI":.~ -. ..... , Razorback sucker. Known 10 Iive.sO)ea1S or more and grow up to 3 feel long and 30 pounds. mesc fish once lhrived in !be Colorado River Basin from W)'Oming 10 Mexico 001 are now on !be endangered species IisL Pag~ 6 The program provides for collaborative problem solving and proactive efforts that reduce costly litigation and, due to its success, has served as a model for other similar programs in the West.