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RESULTS AND DISCUSSION Field collections were completed by November 30, 1981. Unfor- tunately, the report deadline left little time for data analysis. Problems in the development of statistical programs for the MANAGE program, and time required for entering data into the MANAGE system also caused delays. Some studies are deficient in the analysis or data have not been retrieved from the MANAGE system. It will be necessary to supplement parts of this report for completeness. Hopefully NPS and FWS can work together in 1982 to supplement the data analysis and data interpretation for the endangered fishes requirements within DNM. Deficiencies on data analysis have been identified in the text where appropriate. Survey of Habitat and Relationships of Fishes General Joseph et al. (1977) divided streams of the upper Colorado River Basin into three zones: 1. Upper or headwaters - "trout water" having cold temperatures, clear water and high gradients. Substrate is rocky, primary productivity is significant, benthic invertebrates are substantial. 2. Intermediate - warmer water, less gradient, having greater flows with increased levels of suspended and dissolved solids. Waters clear except during runoff and rainy periods. Rocky to sandy substrate; abundant benthic invertebrates in rocky areas to scarce in sandy areas. Cyprinid and catostomid fishes predominate. Primary production is high. 3. Lower - large river channels, divided into two subunits; canyon areas of steep gradient, rocky bottoms and meandering river sections with sand-silt bottoms. Water in this zone is warm, turbid, high in nutrients. Primary production is low, benthic invertebrates dependent on substrate. Fish species composition variable but dominated by cyprinids, catostomids and influenced by introduced fish species. Although Joseph et al. (1977) provides a good general framework and is useful for conceptualization, there are some exceptions in the Yampa River. According to the previous classification, the upper Yampa River (above the study area) would be considered as a Zone 1 stream, the mid Yampa as a Zone 2 stream, the lower Yampa as a Zone 3 stream, and the Green River as a Zone 3 stream. In terms of gradient and substrate, however, Stratum 5 on the Yampa River would be within Zone 1. Also, the entire Yampa River study area is influenced by introduced species, a characteristic of Joseph's Zone 3. In addition, the Green River within DNM study area (especially Strata G4 and G3) is colder than other sections (influence of Flaming Gorge Dam) and supports significant numbers of trout, a Zone 1 characteristic. 17