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<br /> <br />00.7,) <br /> <br /> 70 <br /> 60 <br />=> <br />t- 50 <br /><< <br />c <br />ro <br />w 40 <br />" <br /> 3D <br /> 20 <br /> 133 <br /> <br />Colorado <br /> <br />162 <br /> <br />200 230 <br />River Mile <br /> <br />117 <br /> <br />Yampa <br /> <br />~ <br /> <br />93 <br /> <br />Figure 6. Mean annual lhcrmalunils (ATU) available for Colorado p;Keminn\lW gro",1h at <br />four lo(:ali{ln~ on the Colorado KlVer and two on the Yampa River for comparison Dashed <br />horizontal lines indicate sites on each river with similar lhernlal regimes River mile (mIl 133 <br />is near Ihe Colorado/Utah stale line. rm 182 is 3 miles downstream oflhe lop of the 15-mile <br />reach, ml 200 is 7 mites upstream ofeamco, ml 230 is at. Rulison On the Yampa River, rm <br /><)) ;~ al Juniper Spnngs (the Vampa reach where densities of Colorado pikcminnow are <br />hi!.dll"I). rm 11715 near Sheep Creek (the Sill' of Nesler's [1995] most upstream Colorado <br />plkcllllnn('>wcapture) Data arc from Osmund'IC>n (l999a) <br /> <br />only 67% oflhal al lhe stalelille, amI at <br />Rul;S(lIl,olllyS2%(Fig b) <br />..\llhoughabulldantforagemaycompcll- <br />sate for slow growthcauo;cd by low tcmpera- <br />lures, there;s a point it which tempcratures <br />are so limite4 thai additional food cannot <br />make up for Ihe temperature shortfall and <br />glowthslows What defines the upstream <br />range ufthis spccies is likely a Icmperaturc <br />thrtshold, below which annual !!,fO....1h is <br />;nsufficitnt Co]oradopikcminntlwcanlikely <br />gauge abUllt where this minimum thermal <br />regime occurs and ;ndividual home ranges <br />arethercforeestablishednofimherupslream <br />oflhis pOInt <br />In Ihe Vampa R,vO,'r, fish have unre- <br />stricted upslream access Nesler (1995) <br /> <br />found adult Colorado pikeminnow 111 Ihe <br />Vampa as far upstream as river mile(nn) <br />117 This location has an average ATU <br />val~leofahoul41 On the Colorado River, <br />the location with the same mean A TU <br />occurs at appro~imalely rm 199, or aooul <br />14 miles upstream of Palisade USing the <br />Vampa River as a model, Osmund>on <br />(l9?9a) Mlggesled that Coluradu pikemm- <br />I1UW m the upper Coltlrado Ri\ICr should be <br />able to eSlablish home ranges upmeam <br />almosl as far as De Beque, Colorado, once <br />passage is provided ..\lso, the thermal <br />regime in Ihe reach where Colorado pike- <br />minnow were most abundant in the Yampa <br />Rive' averaged 4b 5 ATU (rm 93) The <br />analogue to Ihis sill." inthe Coloradu River <br /> <br />10 <br />