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01'786 . smallmouth bass, common carp, and channel catfish) advancing from the lower river reaches and Lake Mead. These prospects call for a much more aggressive pursuit of modeling approaches that incorporate the recent responses as a calibration process. Question: What are the food base requirements for HBC and RBT? Need/Rationale: Critical to stabilizing the HBC population in the canyon is a clear ecosystem level understanding of the effects of the food base on the HBC and RBT population. Because there is substantial diet overlap between these two species and they are both of concern to multiple groups, we must detennine what their primary food resources are and how dam operations influence those resources. Approach: The historic focus of the food base research has been on biomass and standing stocks (algae, invertebrates). However, their huge variability over space and time made it impossible to make inferences on the status and trends of the food base. Therefore, the recommended approach is to begin: . . A stable isotope analysis that would identify the energetic base (allochthonous, autochothonous) in this system and serve to guide core monitoring for the food base program. Isotopic signatures of the HBC and RBT combined with food gut analyses can tell us if the primary basal resource that supports these fish is algae or detritus and how this varies from Lees Ferry to the LCR. Note, the purpose here is not to develop a predictive model between food levels and fish but to use this tool to detennine what aspect of the food base the fish rely on so that long tenn monitoring of those aspects can be begun quickly. . Collecting water and suspended sediment samples at multiple points along the river for analysis of chlorophyll and nutrients: carbon (DOC and POC), nitrogen (DIN, DON), and phosphate phosphorus. This serves the dual purpose of providing a water quality monitoring baseline for pre TCD deployment, and should allow for the future development ofa carbon budget, which ultimately is necessary for and detennining if food limitation is an Issue. Question: What comprehensive cultural resource strategy is most appropriate for FY 2005-2009? Question: How can flow impacted cultural site resource loss be best mitigated in FY 2005-2009? Need/Rationale: Progress in the cultural program has been hampered over the years due to agency politics and differences in interpretation over agency roles and authorities. Until these issues are resolved, a science strategy cannot be successfully implemented. There are three major material deficiencies within the cultural resources program, as it currently stands, that prevent fOlWard progress in the program: . USGS SBSC GCMRC Strategic Science Plan - FY 2005-2009 Draft, October 22, 2004 17