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;:~~ HOLDEN AND STALNAKER-COLORADO RIVER FISHES 223 II abundant throughout their range. Older fishermen remembered catching them readily as youths. Jordan (1891) seined several from the Gunnison River near Delta and at Green River, Utah. Thus, once a common fish, it is now very rare. Humpback chub complex-Gila cypha Miller. Members of the humpback chub complex were collected in areas 2, 3, 4, and 11. Most specimens were taken from eddies adjacent to fast currents. Only 61 were taken. Of these, 26 were collected near Echo Park in areas 2 and 3 in 1969, most from one eddy. Fifteen were taken in area 11 in 1967; only one was taken in the same area with increased effort in 1970, suggesting a decrease in abundance had occurred. Young chubs collected in area 4, had noticeable nuchal humps and other characters suggesting they were of the humpback chub complex. Juveniles were not found in any other area. The humpback chub was first described by Miller (1946) and has been seldom col- lected since that time. Smith (1960) re- ported 18 from Hideout Canyon of the Flaming Gorge basin, most from one small area. Sigler and Miller (1963) reported it from the Colorado River near Moab, Utah, and the White River near Bonanza, Utah. Utah and Alizona Fish and Game person- nel collected numerous members of this complex in Lake Powell in the early-mid 1960's (Holden and Stalnaker 1970). Few specimens have been seen there recently (Steve Gloss, Utah Division of Wildlife Re- sources, personal communication). Miller (1955) repOlied remains of this group from archaeological sites in the lower Colorado basin. Thus, this form ranged throughout the main stream of the Colorado basin, and it appears doubtful that it was abun- dant in the 20th Century as few published accounts are available. Colorado squawfish-Ptychocheilus lu- cius Gl:rarJ. Colorado squawfish were col- lected throughout the study area in small numbers. Three hundred adults were col- lected, 261 of these from area 2. Young-of-the-year squawfish were col- lected in area 4 in 1971 .nd 1972 and in " " , e area 5 in 1970 and 1971. Juveniles were abundant around Echo Park in 1968, but very few were caught in 1969 and none could be located in 1970 or 1971, undoubt- edly a reflection of poor spawning success. Reasons for this are unknown as the num- bers of adults did not decrease. Vanicek and Kramer (1969) found that successful spawning was the rule, with very few weak year classes of squawfish in this area. Juveniles were collected in small num- bers in areas 4 and 5 throughout the study. Three .juveniles were collected in area 7 in 1971. Adults were collected in all habitat types but mainly in slow water (eddies,backwa- ters, and flooded canyon mouths). Juveniles were caught in backwater areas and small eddies typically 60-90 cm deep. Young of the year were taken in shallow, warm, stagnant areas usually between a sandbar and the bank. Congregations of ripe male squawfish were collected in area 2 in July and early August of each year, 1968-70. The origins of this migration are not known, although reproduction is the hypothesized purpose (Holden and Stalnaker 1974). One or two squawfish were taken by fishermen each year in Lake Powell, but no large numbers have been noted (Steve Gloss, Utah Divi- sion of Wildlife Resources, personal com- munication). Colorado squawfish have been repOlied to reach at least 36 kg and 150 cm in length (Jordan and Evermann 1896). The largest specimens seen dUJing the study were not weighed but were estimated at 7 kg. Older fishermen rccall catching a fair number of fish near 22 kg, and stories of larger fish were common till the 1930's. Several reasons for the decline were cited by fisherman, the most common being construction of dams. This fish has appar- ently suffered great reductions in popula- tion size within the last 30 to 40 years. Speckled dace -Rhinichthys osculus Girard. The native speckled dace was col- lected throughout the sLndy area. It was abundant in most areas, but less common in large, warm sections of the Il1<L i'l\'Crs.