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mesohabitats during the 24-hour observations. On these occasions the fish returned to its starting location within the 24-hour period. It is not known if fish observed in 1996 moved to an adjoining habitat due to low flows or remained in the discrete mesohabitat in response to prey availability. Fish were observed moving between mesohabitats during the lowest flows in 1996 (approximately 70 cfs), but fish were not observed moving between discrete mesohabitats during the 24-hour observations. The movement between adjoining mesohabitats in 1997 may be in response to several factors. The higher base flows (> 320 cfs), could have more readily allowed movement between mesohabitats. The movement also could have been in response to location of prey specIes. In Yampa Canyon two humpback chub (river mile (RM) 18. I and 35.3) were monitored over a twenty- four hour period between 6-8 August 1997. No other humpback chub were located on the ground during the 1997 field season. Both fish remained in the general vicinity that they were located throughout the 24 four period showing only short local movements. One fish was found below Teepee Rapid and remained in shallow water, nearshore habitat throughoutthe 24 hours monitored. Average water column depth used was 1.3 ft, average water column velocity was 0.52 fils and the dominant substrate was boulder. Another fish was located at river mile 18. I, above Mathers Hole, and also remained in nearshore habitat and did not move outside of the eddy habitat it occupied. The second fish was found in deeper water, exceeding 5.9 ft, but used nearly the same average water column velocity (0.56 fils) and was also found associated with boulder or bedrock substrate. Despite using different depths, both humpback chub used habitats adjacent to the shoreline. In the absence of a large telemetry database on habitat use, a summary of habitat use data by the humpback chub in Yampa Canyon was analyzed. A comparison of 153 humpback chub collected from Yampa Canyon between 1980 and 1997 indicated that most fish were collected in eddy or eddy-related habitats. The same database indicated that most fish collected were associated with shoreline structure rather than main channel or side channel habitats. Of the five Colorado pikeminnow implanted with radio transmitters in Yampa Canyon in 1996, two left Yampa Canyon during the second week of August, one month following implantation. One fish either died or lost its transmitter and two fish remained in Yampa Canyon through the low flow periodunti/ at least 29 October 96. Of the two Colorado pikeminnow that remained in Yampa Canyon, one remained in upper reach of the canyon and the other in the mid- to lower- reach of the canyon. Both fish appeared to remain in a general area of the river following August 1996. One fish ranged from RM 12.1 to 20.1, and 11