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<br />'1 <br />\.~~ <br /> <br />17 <br /> <br />'. <br /> <br />develop a better understanding offoodweb linkages within the spatial distribution of the entire <br />fish community, <br />In Lees Ferry the food base derived from primary production is considered an important <br />biotic resource because of its direct linkage to higher trophic levels, potential limitations (density <br />dependence), use and availability required to support the waterfowl and rainbow trout fishery, <br />Algae/macrophytes and invertebrates consisting mostly of midge larvae (chironomids), and <br />amphipods (Gammarus) form the major components of the aquatic food base in Lees Ferry, The <br />conventional phyto-benthic and invertebrate monitoring will be continued in this upstream <br />section. The frequency of these sampling efforts will be intensified to monitor effects due to <br />experimental fluctuating flows and beach habitat building flows. Additionally, a new method for <br />measuring community metabolism and respiration will be assessed to. determine its feasibility for <br />estimating primary production in Lees Ferry, Contingent on study outcome, community <br />metabolism may be more effective and serve as a surrogate to conventional indexes used for <br />evaluating primary production. <br />Several research projects assessing food-fish linkages have been recently implemented, <br />These include: bioenergetics modeling (Peterson 2003) and diet and predation associated with <br />non-native trout removal project at the LCR (Coggins and Yard 2003), Following the aquatic <br />protocol evaluation panel recommendations, it is proposed that an organic mass balance project <br />be used as an indicator of system-wide production and export, A request for proposals will be <br />developed during 2004 for this initiative, <br /> <br />Fisberies Resources <br />The Lees Ferry trout fishery has developed a stock assessment model using historic <br />angling data and catch effort data from past monitoring efforts, The model provides a three-to <br />five-year view of the state of this fishery resource and provides an opportunity to evaluate <br />management strategies associated with this fishery (Speas et aI., 200 I), The monitoring program <br />that is in place through a cooperative effort between GCMRC and Arizona Game and Fish <br />includes the historic fixed sampling sites and new random, stratified sites based on shoreline <br />type, The program's design is intended to increase sampling areas to better characterize the trout <br />fishery as a whole, Recent data indicate that the fishery is strongly influenced by diel changes in <br />flows and that growth is likely density dependent: The stable flows associated with ROD <br /> <br />GCMRC FY2005-2006 Draft Annual Work Plan (November 10,2003) <br />