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<br />105.2-111.2; Table 1). In 2004, we added Lily Park (RM 50.5 - 55.5) as another <br />treatment reach, switched locations of Little Yampa Canyon control and treatment <br />reaches, and increased the length of those reaches to 12-miles (control, RM <br />124.0-112.0; treatment RM 112.0-100.0). Reach length was increased because of <br />extensive movement of smallmouth bass observed between shorter 6-mile reaches in <br />the previous year. Those reach lengths remained the same in 2005. However, <br />continued high rates of movement between control and treatment reaches in 2004 and <br />2005 resulted in the elimination of the control reach and expansion of the treatment <br />reach to 24-miles in Little Yampa Canyon in 2006 and 2007. <br /> <br />Boat electrofishing occurred from April through mid-July when flow was sufficient <br />(> 1000 cfs) to navigate the river with 17-ft. aluminum, Jon-boats fitted with outboard jet <br />motors. We sampled both shorelines concurrently with two electrofishing boats in a <br />downstream direction and covered about 6 miles per day until the entire reach was <br />sampled. Each boat used pulsed-DC current, one boat with a Coffelt and the other with <br />a Smith-Root electrofishing unit. Duration of electrofishing effort was obtained from a <br />timer on each electrofishing unit. Each reach was sampled on four to ten occasions per <br />year with an interval of 4-10 days between occasions. Fish marked and released on <br />the first one or two sample occasions each year served as the mark for annual <br />abundance estimates. Study reaches were divided into 1f2-mile sections and we <br />electrofished to the lower terminus of each section before processing fish. Fish that <br />were returned to the river were Floy tagged and released within the 1f2-mile section from <br />which they were captured. Backwater and flooded tributary mouth areas were sampled <br />by electrofishing boat, fyke net, or block-and-shock techniques described by Nesler <br />(1995). To determine spawning locations and timing of smallmouth bass reproduction, <br />we noted guarding males moving off nests and reproductive condition of fish. Adult <br />smallmouth bass were also captured occasionally by angling during periods of low <br />stream discharge. Other nonnative species captured and euthanized included black <br />crappie Pomoxis nigromaculatus, bluegill Lepomis macrochirus, green sunfish L. <br />cyanellus, pumpkinseed L. gibbosus, black bullhead Ameiurus exile, and walleye <br /> <br />5 <br />