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<br />5GJ <br /> <br />2. Characterize habitat of four representative secondary channels <br />a) Characterize habitats seasonally and ih relation to flow regime. <br />b) Relate habitat availability to composition of the fish community and its <br />dynamics. <br /> <br />3. IdentifY potential management actions that might enhance secondary channel habitats for <br />native fishes. <br /> <br />In addition to data obtained by NMGF and UNM personnel, appropriate data from 1) secondary <br />channel emigration/immigration studies (USFWS-NMFRO); 2) early life history studies (UDWR, <br />UNM); 3) habitat mapping and resource utilization (K--B); and 4) Videography (USBR-Denver) <br />will be used in preparation of report on fish community dynamics in secondary channel permanent <br />sites. Appropriate univariate and multivariate statistical procedures will be used in data analysis. <br /> <br />Specific objectives ofthe side by side study are: <br />1. Characterize the fish community of low-velocity, near shore primary channel habitats <br />longitudinally and by geomorphic reach. <br />2. Compare and contrast and composition of near-shore primary channel fish communities <br />with that ofthe adj acent secondary channel( s). <br />3. Characterize the near-shore fish community in relation to near shore habitats. <br />4 Use data obtained in this study to recommend management actions that might enhance <br />native fish status in the San Juan River. <br /> <br />In addition to data obtained by NMGF personnel, appropriate date from 1) secondary channel <br />emigration/immigration studies (USFWS-NMFRO); early life history studies (UDWR, UNM); <br />adult monitoring (USFWS-CRFP); and geomorphology (K-B) will be used in preparation of the <br />"side-by-side" fish community report. Appropriate parametric and nonparametric statistical <br />procedures will be used in data analysis. <br /> <br />A major activity during fiscal year 1997 will involve compilation, analysis, and synthesis of data <br />collected from seasonal secondary channel inventories (1992 through 1997) and of data collected <br />from the secondary channel permanent sites COmrllunity dynamics studies (1993 through 1996). <br />This information will be presented in two major reports. A third report on the "side-by-side" <br />studies will be prepared. <br /> <br />Secondary channels of the San Juan River provide considerable low-velocity habitat. During <br />much of the year these habitats are occupied and numerically dominated by several nonnative fish <br />species. Several of these nonnative species (particularly red shiner and channel catfish) have been <br />implicated in the decline of native fish species. Information obtained from secondary channel fish <br />community studies will be used to evaluate the efficacy of flow manipulations to control nonnative <br />fish species, to determine (in part) the importance of various flow levels in maintenance of <br />different low-velocity habitats, to evaluate the need for and value of mechanical manipulations of <br />secondary channel habitats to improve their quality for native fishes, to characterize life history <br />attributes of nonnative fishes and relate this information to potential control measures and to <br />characterize potential competition among native and nonnative fishes for limiting resources. <br /> <br />23 <br />