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Greater numbers of smallmouth bass were removed in 2005 and 2006, due to greater effort. Years 2005 and 2006 were also the first years of removal of age-0 smallmouth bass from the treatment reach (Hawkins 2005, 2006). In 2005, an abundance estimate of 1,223 smallmouth bass > 150 mm total length (CV = 18%, 2-pass capture-recapture estimate) and a removal of 1,404 bass suggested a removal of> 100% of the population with boat electrofishing over eight removal passes. Another 848 bass were removed that were < 150 mm TL. Many additional fish may have immigrated into the study reach due to escapement of smallmouth bass from Elkhead Reservoir or movement from other adjacent reaches, which is a likely explanation for the number offish removed being greater than the estimated abundance. Evidence of escapement of fish from Elkhead Reservoir is based on recapture of tagged fish that were moved from the Yampa River to the reservoir in prior years or the same year, and were recaptured in the study area. The hypothesis of fish immigration into the study area was also based on an abundance estimate over 5-passes of 2,846 (CV = 11 %), which occurred during the time when bass likely immigrated into the area. A large influx of bass into the study area would result in an inflated estimate, based on a lowered proportion of marked fish that were recaptured in later passes after fish had moved in. It is also possible that abundance estimates were biased ]ow. In 2005, an additiona19,528 small-bodied smallmouth bass (most age-0) were removed by electric seining efforts from late-July to early September. We do not know what proportion of smallmouth bass were removed because there was not an accompanying abundance estimate. Age-0 smallmouth bass abundance in control and treatment reaches started at low levels in mid- July based on electric seine sampling results (Fig. 7A). Mid- to late-July was about the time smallmouth bass finished reproduction in that relatively high and cool flow year (KRB, unpublished otolith aging information). Bass abundance in samples (CPUE) increased rapidly by ]ate August to early September in control and treatment reaches. Smallmouth bass abundance in the treatment reach never achieved the level that they did in the control reach, perhaps because of continuous removals. Smallmouth bass abundance in the control reach remained high and constant through late September, but declined sharply in the treatment reach, a difference that is likely due to removal efforts. Between late September and mid-October, smallmouth bass 12