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(Notropis stramineus) and fathead minnow (Pimephales promelas). Since these three species were difficult to distinguish in the larval stages they were combined into one ~~ategory for analyses, and were collectively denoted asnon-native cyprinids (NNC). The other seven non- native species, listed in Appendix B, were collected sporadically and collectively comprised from 0.0 to 6.75 % of the total number offish larvae (Table 1). Species composition at Westwater revealed a higher percentage of nattive than non-native fish species. (Table 1, and Figure 2). Gila spp. and bluehead sucker composed the majority of native fish collections. Colorado pikeminnow larvae composed a small percent of the total native fish even in 1993, when more Colorado pikeminnow larvae were collected (156) than all three NNC species (96). In 1994, the lowest water year, the percentage of noii-native fish was greater than native. At Moab, the ratio of native to non-native fish species was reversed. The three non-native cyprinids (NNC) dominated the catch, pazticulazly in 1994 when they compri;;ed 85% of the total fish collected. Colorado pikeminnow were the most abundant native species in 1995 and 1996 (Figure 3). Table 1. Relative abundance offish species collected in the drift, Colorado Riiver, 1992 - 1996. Year Total fish Colorado Other native Non-native Other non-native collected pikeminnow species cyprinids species WESTWATER 1992 8512 1.01 82.86 16.13 0.0 1993 4759 3.36 87.88 2.02 6.75 1994 2003 1.25 31.35 64.20 3.20 1995 670 4.18 69.85 25.22 0.75 1996 1876 3.09 82.41 13.54 0.96 MOAB 1992 4473 6.48 23.30 67.34 2.88 1993 4101 3.41 33.07 58.89 4.63 1994 3450 0.81 8.84 85.13 5.22 1995 2573 13.91 21.30 63.16 1.63 1996 2575 18.37 21.32 58.76 1.55 1996 day 2682 17.23 10.92 70.66 1.19 Annual Colorado pikeminnow drift abundance The annual timing and duration of Colorado pikeminnow drift and spawning was documented. Larval pikeminnow were collected each yeaz at both sites (Table 2). Each year sampling began one to two weeks before any Colorado pikeminnow were collected. The date the first Colorado pikeminnow was collected vazied from the earliest on June 27 (1994) at Moab to 4