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Net Catches. During the pikeminnow population estimate study, (Doug Osmundson, unpublished data), the point estimate for the river net catch rate (average number of fish per trammel net) for sub-adult and adult pikeminnow in the upper reach of the Colorado River was reported to be the highest in 1998 (0.97 fish/net). This coincided with the peak of 23 pikeminnow that used the Redlands passageway in July and August 1998. In 1999 the river net catch rate for pikeminnow declined about 20% (0.78 fish/net) which coincided with the decline of pikeminnow collected in the fish trap. However, in 2000, the river net catch rate increased slightly (0.81 fish/net) while the number of pikeminnow in the fish trap-declined slightly further. Between 1998 and 2000, the net catch rates were not significant (Ps 0.05). Therefore, net catch rate data does not explain the decline. Length Frequency. Length-frequency analysis of Colorado pikeminnow captured from the upper reach during the spring/early summer of 1998-2000 shows that a dominant length class increased slightly during this period (Appendix; Figure E.2.). Although the length increased, smaller size classes of pikeminnow (400-550 mm class) were still being recruited into the river population. Consequently, during 1998-2000, a proportional number of pikeminnow were available in the river population to move through the passageway, similar to sizes of pikeminnow seen in fish trap catches during 1997 and 1998. Body Condition. The mean relative body condition of pikeminnow in the lower reach of the Colorado River during the 1998-2000 pikeminnow population estimate was lowest in 1998 (0.81) compared to 0.87 in 1999 and 0.90 in 2000. The mean relative body condition of pikeminnow in the lower reach during 1998 and 1999 was lower than the mean body condition during 1992-1994 (although not significant at P5 0.05). There are no data for relative body condition for 1995- 1997 in the lower reach. Data from this study have demonstrated that pikeminnow originally captured in the lower reach of the Colorado River have moved upstream and have been recaptured in the Redlands fish trap. Three pikeminnow collected in the fish trap in 1997 were recaptures that had been previously captured in the Colorado River downstream from Moab (Appendix; Table E.1.). Two other pikeminnow, one each in 1998 and 1999, captured in the fish trap had previously been captured in the lower reach of the Colorado River. The reason for upstream movements by smaller pikeminnow from the lower to upper reach were advanced by Osmundson et al. (1998) and were discussed in an earlier section (Fish Trap: Colorado pikeminnow: Size). Population Size. Pikeminnow population point estimates increased from about 344 in the early 1990's to 442 individuals (28%) in the late 1990's in the lower reach. Accordingly, during the same period in the upper reach, the number of pikeminnow increased from about 253 to 407, an increase of 61% (Doug 34