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<br />0015040 - <br /> <br />be completed and available for review in conjunction with the review of environmental <br />compliance documents. Although many potential positive and negative effects of a TCD <br />on endangered fish and other Colorado River resources have been postulated during <br />investigations conducted to date, few of these projected outcomes can be known with <br />certainty and thus testing through a research and monitoring program will be necessary <br />to make these determinations. <br /> <br />ELEMENT 1.C <br /> <br />Determine responses of native fishes in Grand Canyon to various temperature regimes <br />and river flows of the experimental flows and other operations of Glen Canyon Dam. <br /> <br />PROGRESS ON ELEMENT 1.C <br /> <br />Vernieu (2003) evaluated warming of mainstem and nearshore habitats during the low <br />steady flows of summer 2000. Rogers and others (2003b) measured drift and benthic <br />biomass under the low steady flows and powerplant-capacity spike flows in the LSSF <br />experiment. Trammel and others (2003) investigated responses of native fishes to the <br />same low steady and spike flows. A preliminary report on the mechanical removal of <br />non-natives was submitted by Coggins and Yard (2003). Rogers and others (2003a) <br />examined non-native salmonid distribution and abundance from RM 12 to 218. <br />Johnstone and others (2003) reported on native fish monitoring efforts and made <br />recommendations for approaches to setting up a standardized monitoring program. <br /> <br />One of the impediments to identifying responses of native fish to changes in water <br />temperature regimes and river flows has been the lack of a consistent monitoring plan <br />and assessment analysis. Under the auspices of GCMRC, with the aid of Dr. Carl <br />Walters, University of British Columbia, a stock assessment model has been developed <br />and is being applied to both HBC and f1annelmouth sucker. The stock assessment <br />approach concentrates on changes in the number of individuals recruiting to the <br />populations of native fishes, which for humpback chub is ages 3-4. A recent compilation <br />of results of this work indicates that the number of recruiting individuals to the LCR <br />population of HBC declined from 1993-1999, the most recent year for which they have <br />estimates (Coggins and others 2003). Concern within the GCDAMP arose over the <br />controversy surrounding the different methods and models used to assess humpback <br />chub populations in both the Upper Basin and in the Grand Canyon. In response to this <br />concern, GCMRC convened a Panel of Independent Reviewers to meet with <br />representatives of ongoing programs in the Upper Basin and Grand Canyon. The goal of <br />this panel was to review current methods and make recommendations to improve the <br />accuracy and precision associated with the parameter estimates (Le., abundance, <br />population growth rate, and recruitment) from the various models being used. The Panel <br />of Independent Reviewers found that the competing models used in the Upper Basin <br />and Grand Canyon were appropriate for their respective locations and made <br />recommendations to improve their use in the future (Kitchell and others 2003). A series <br />of meetings was proposed to examine data on humpback chubs collected in both the <br />Upper Basin and in the Grand Canyon. <br /> <br />6 <br />