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supported the Preferred Alternative as originally proposed, the USBR believed the DEIS would not be acceptable to the USFWS unless this element was added. The Endangered Fish Research program essentially mimics flows in the Seasonally Adjusted Steady Flow alternative, the Alternative supported by the USFWS. Also, since this element only appears in the Preferred Alternative, any other Alternative chosen would be devoid of the Endangered Fish Research element. Research to determine responses and impacts on endangered and native fish by experimental flows should be done but the approach should not be fixed as a part of the EIS's Preferred Alternative. This will limit the flexibility inevitably needed to modify research efforts in response to findings. In contrast with the use of tributaries to enhance Humpback chub populations, the Endangered Fish Research element attempts to achieve habitat changes in the mainstem river through flow , modifications. This is suggested despite the recognition that conditions during the period proposed for study are not conducive to successful Humpback chub spawning in the mainstem. . ", !, .' No evidence exists that numbers of Humpback chub have decreased since dam construction although their range apparently has been reduced by cold water releases. Fish extinction through maintenance of normal operations at Glen Canyon Dam has not been established as a threat by either GeES I or II. Recovery of endangered fish through use of steady flows is speculative at best. Under this situation, experimenting with habitat change to make things better carries significant risks and few benefits. There are several anticipated problems with this approach. Please respond to these concerns and explain why these do not negate use of the Preferred Alternative. ,- '... , 0.. ,~. * Steady flow releases from the dam as part of an endangered fish research program should be considered with other experiments as part of the Adaptive Management Program to be implemented after the Record of Decision. The present approach is an independent habitat component whose results would have no relevancy to reality and could not be combined later with other components. ;~. :.~. -i. ...~ ~ ~. :$ * Presently, no models exist to help the Bureau determine incremental relationships between flow and river conditions favorable to endangered fish which are exclusive of other variables. * We support the proposal to test hypotheses with a set of specific flows developed through the Adaptive Management Program. However, it makes little sense to burden the Preferred Alternative with implementation of a specific set of research flows in the initial years of flow modifications when 12