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1 1 1 documented collections of introduced red shiner Cyprinella lutrensis, sand shiner Notropis stramineus, and white sucker Catostomus commersoni, were made. Sampling during this study (1994-1996) detected a total of eight native fishes, 14 introduced ones, and five hybrid sucker combinations. Notable was presence of a moderately- abundant population of Colorado pikeminnow. Roundtail chub was rare, and mountain sucker was absent. Similar to previous studies, bonytail and humpback chub were not detected in the study area, and razorback sucker was rare (N = 1). Reproduction by Colorado pikeminnow and razorback sucker was not detected in this or the prior study. Reproduction by six other native taxa, including roundtail chub, was detected. Sampling also detected the presence of three additional hybrid sucker combinations and three newly established piscivores, northern pike Esox Lucius, green sunfish Lepomis cyanellus, and smallmouth bass Micropterus dolomieu. Non- native Utah chub Gila atraria, and creek chub Semotilus atromaculatus, which were rare in 1978-1980, were not detected during sampling in 1994-1996. Changes in the Lodore Canyon fish community between 1978-1980 and 1994- 1996.-Comparison of collections made in the 1978-1980 period to those made from 1994-1996 suggested moderate shifts in abundance patterns of native species and increased abundance and diversity ofnon-native species and hybrid catostomids in the Green River in Lodore Canyon. At the upper Lodore Canyon site, collections in 1978-1980 revealed the presence of six native fishes, 10 introduced taxa, and one hybrid (Table 2). Collections made in 1994-1996 also revealed the presence of six native fishes, 9 introduced taxa, and three hybrids. Only four native taxa, mountain whitefish, speckled dace Rhinichthys osculus, flannelmouth sucker Catostomus latipinnis, and bluehead sucker Catostomus discobolus ,were common between the two periods. Small numbers of roundtail chub and mountain sucker were present in early collections but were absent in later ones, and Colorado pikeminnow, mottled sculpin, and bluehead X flannelmouth sucker hybrids were collected in the later period but not in the earlier one. Seven introduced taxa and one hybrid sucker combination were common to each period. Early collections documented the presence of Utah chub and red shiner, which were not collected in 1994-1996. Contemporary 15