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, ',M' Control: ' , I ,~j::r" . 'enaangered fish and accommodating trout and kokanee in Flaming Gorge Reservoir $;:;fr~;'...,j .' . . . _ >. ." . . '.' "., . Photo by ~onnl9 Young The scouring effect of.somewhat higher' releases freshens the river by removing decaying material from vegetation, cleaning spawning beds, Inaeasing Insect , production and generally Improving trout fishing opportunities. ' I ?- I 992,the SeIVice issued an tlpin- IOn on the operatIOn 'of Flaming , , Gorge Dam, recommending afiye- ' year experimental period of higher re- leases in the spring and lower, more , stable flows in th~ summer. Fiim guidelines have not yet been established for winter flows. Rci1eases will be varied each year to determine which flows are best for endangered fish.', . ' , ' , TroUt generally' are not considered competitors' with endangered fish and Can be stocked anywhere in the upper Colorado River Basin. Additionally, re- leases aimed at benefiting endangered , fishes will also benefit'the trout fishery below the dam. In some 'cases however, river flows needed for endangered fish may not be ideal for irout. For example studies on the Gteen River revealed the , following: ~ Extremely high releases for an ex- tended time period generally are , , not beneficial to trout.' The fish . , , expend more energy trying to find slower moving waters. ,Also, 'trout do not grow' as ' quickly 'In the colder water thatresu1t~ from these'releases. ~' However,' a positive, is that at ' somewhat lower levels, the scour- ing ,effect could, "freshen" the ,river by removing decaying mate- rial ,from vegetaiion, beds, clean- , ing trout spawning bedS, improv- ing the currently low insect pro- , ,duction m'the aXea and generally improving trout fishing opportuni- ties. ~During high-water years, more water may have to be released in winter or early spring to make space for runoff from the next , spring. This would come at a time when trout are least able to' find and metabolize food and have less' energy to find suitable water ve- 7 locities or staym the same loca- tion in high-velocitY water. ~ In the past, flows fluctuated from 800 to 4,500 cfs each day for 'power prpduction. Now, that more stable releases are being made for endangered fishes, trout fry have a better chance of' sUIviving the summer and fishing conditions are more dependable. ~ The Ut3.h Division of Wildlife Re- 'sources has,been'stocking trout at various times m,spring and early , summer to determine which pe- riod produces the best survival and growth. Early results indicate stocking at the end of high spring flows is most successful. ' ~ Below the' dam, the suivival rate of young rambow and cutthroat , trout is po'or. Bioloiiits believe this, is because the area produces few .of the backwaters young trout need and because highcenergy de- mands have: been placed on the 'fish'when river flows have fluctu- ated to meet power needs. Impacts, on trout and kokanee in , Flaming Gorge Reservoir " , ~ Kokanee spawn from late October through November. When water is ,~released during the winter, the reservoir leVer can' drop' below some of the kokanee spawning ar- eas, killing eggs, However, biolo- gists have recommended that win- , ter releases be lower than' m the past to. stay in keeping with the ne'eds of the endangered fish. They believe this, measure will also help to preserve kokannee spawning sites. ~ The voracious appetites of lake 'lrout, however; are having an im- , pact. They are consuming increas- ingly large numbers of kokanee -- m the neighborhood of 900,000 annUally. ~ Both rainbow trout and bass ap- pear unaffected by the changes in dam operations. ' ' .