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/'''''''='2 ...c".....;;,;;.~#dj~.,.,~;,;;"';,;;;,;~'&;;:;:;;Cd~~i.:liI.XSi~,~i<;,~"';;;~;.k,,j"\,\,;';,;i~,>i.:;">;;"""-'"'."~;;St;'I;.;;';i.l'&"",,,,,,,:6L_"";';~;;.o.~,j. ", ,r :{ ~ i ;i l .~ , <1. 1 1 'j 224 TRANS. AMER. FISH. SOC., 1975, NO.2 "i In areas 3 and 8, they often comprised the majority of specimens in seine hauls. Dace were collected in most habitats, but were typically associated with small riffles or areas of current. In area 12 they were abundant in almost all tributaries, but were not collected in the main river except at mouths of tributaries. Several specimens collected in area 5 in 1970 appeared ex- tremely silvery and lacked spots or blotches. Later attempts in the same area failed to produce additional specimens. The silvery color was assumed to be a re- sponse to the turbid water and sandy bot- tom of the area. This phenomenon is common among fishes inhabiting such areas (flannel mouth suckers in the same area were also silvery). Redside shiner-Richardsonills balteatus Richardson. The introduced redside shiner was abundant in areas 1, 2, and 3. The redside shiner was collected by seine from most habitats except fast water and riffles. Simon (1946) reported that this fish was established in upper Green River of Utah and Wyoming in ] 938. A decrease in red- side shiner abundance was nOled near the southern boundary of Dinosaur National Monument in 1971 whell red shiners be- came common there. Fathead minnow-Pimephalcs promeJlas Rafinesqlle. Fathead minnows were eorn- mon throughout much of the study area but never abundant. Only one was taken in area 12. They were seldom taken in areas of current but typically were found in quiet backwaters. They may have be- come common in various pints of the basin at different times due to introduction as bait/ish. Miller (1952) reported the use of fathead minnows as baitfish on the lower Colorado River. but suggested they were not then common in the river. :\Iiller and Lowe (19M.) reported fatheads in the Paria River at the lower end of Glen Canyon. in 1952. Smith (1959) made the first Utah col- lection in Glen Canyon. and Smith (1960) first reported fatheads from upper Green River of Utah. No earlier reports of fal- heads in the Colorado basin exist; there- fore the site and date of introduction is unknown. Due to small populatiom; the fathead minnow is not now a serious com- petitor of native species. Carp-Cyprinus carpio Linnaeus. The ubiquitous carp was taken throughout the study area, but seldom in large numbers. It was abundant only in area 8 and a few quiet water areas throughout the study area. The area near Grand Junction (area 8), although of rapid current, was enriched by man's activities, providing excellent carp habitat. The area below the city sew- age disposal plant was extremely produc- tive of carp; many were very large. Small carp were scined from most slow backwaters throughout the study area, al- though seldom in large numbers. Adult carp were often seen feeding on surface debris in eddies. Beckman (1952) reported that earp were introduced into Colorado in 1882. It may have moved into the Colorado River system soon thereafter. Red shiner-Notropis lutrensis Bm:rd and Girard. A newcomer to the upper Col- orado River basin, the red shiner was ex- tending its range up the Green River dur- ing the study. 'I'his species was abundant in the Colorado Hiver and the Green River upstream to Desolation Canyon in 1968. A few specimens were collected at Ouray, Utah, in 1969. It was common to abundant in the Green Hi vcr near the southern boundary of Dinosaur National Monument by 1971. Two specimens were collected near Echo Park and one in the White Ri vcr in ] 971 also. Red shiners were collected from most habitots, except fast water, and were the most abundant fish in seine hauls from the middle Colorado and lower Green Rivers. ;\tfiller (1952) doubtecl the red shiner, then being used as a baitfish, would he- eome established in the lower Colorado basin due to unfavorable habitat. However, Hubbs (1954) reportcd the shiner estab- lishedin that same area by 1953. The question arises whether this species entered the upper basin through Grand Canyon. or whcther it was separately 'in- troduced. Neither Smith (1959) nor McDonald and Dotson (1960) collected the red shiner in Glen CanyoII. Judging from present data, Glen Canyon should have