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<br />226
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<br />TRANS. AMER. FISH. SOC., 1975, NO.2
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<br />White sucker-Catostomus commersoni
<br />Lacepede. The introduced white sucker is
<br />abundant only in area 1. It was rare in
<br />area 2 in 1968 and 1969 but was collected
<br />there in greater numbers in 1970 (Table 2).
<br />It is also rare in areas 3 and 9. The white
<br />sucker is very common in areas upstream
<br />from the study area, at times becoming a
<br />nuisance in areas managed for trout.
<br />Hubbs, Hubbs, and Johnson (1943)
<br />stated the white sucker was introduced
<br />into the Colorado River in about 1926; Mil-
<br />ler (1952) said it was introduced in the
<br />Colorado above Rifle about 1938. Separate
<br />introduction into upper Yampa River is as-
<br />sumed from its present distribution.
<br />Longnose sucker-Catostomus catos-
<br />tomus Forster. The longnose sucker is
<br />another introduced sucker very common in
<br />the headwaters of the upper Colorado
<br />basin. Only one longnosc sucker was col-
<br />lected during the study in arca 9. A
<br />species associated with colder trout
<br />habitat, it apparently invadcd the study
<br />area occasionally. Beckman (1952) stated
<br />that the longnose sucker has "just re-
<br />cently" been planted in the Colorado sys-
<br />tem.
<br />Humpback sucker-Xyrauchen tcxanus
<br />Abbott. The eudemic humpback sucker
<br />was collected only in the middle and lower
<br />sections of the study area. It is rare in all
<br />areas; only 53 were taken during the
<br />study. It was collectcd almost exclusively
<br />in stagnant or quiet-watcr areas. Hump-
<br />back suckers wcre caught in relatively
<br />largc numbers (10-15) in a quiet, cutoff
<br />channel at the mouth of Yarnpa River in
<br />early March and late Novembcr. 1970.
<br />They were also concentrated in flooded
<br />mouths of washes in Canyoulands National
<br />Park area during high water of early
<br />summer, 1971.
<br />Juvenile humpback suckers arc relatively
<br />unknown. Winn and i\lilIer (1954) de-
<br />scribed larval humpback suckers collected
<br />below Lake Mead. Douglas (1952) reported
<br />spawning humpback suckers from Lake
<br />Havasu, and Jonez and SUlllner (195,0 ob-
<br />served spawning in Lakes Mead and
<br />l\tohave, but no juveniles were reported
<br />
<br />
<br />
<br />later (Minckley and Deacon 1968). Smith
<br />(1959) collected two specimens 3.75 cm in
<br />length from Glen Canyon. It is probable
<br />that young humpback suckers appear
<br />nearly identical to young flannelmouth
<br />suckers on field examination and are not
<br />easily distinguished.
<br />Jordan (1891) found the humpback
<br />sucker abundant in the study area, where
<br />local residents used it a great deal for
<br />food. Its large size (3.6-4 kg) and easy ac-
<br />cessibility with seines made it an ideal
<br />food fish. Vanicek, Kramer, and Franklin
<br />(1970) reported that humpback suckers
<br />were relatively rare in area 3 but sug-
<br />gested they were also rare before closurc
<br />of Flaming Gorge Dam.
<br />The data indicate a markcd reduction in
<br />humpback suckers during this century,
<br />from abundance to extreme rarity.
<br />
<br />/ctaluridae
<br />
<br />Channel catfish-Ictalurus punctatus
<br />Rafinesque. One of the most common
<br />fishes of the middle and upper Colorado
<br />basin, the introduced channel catfish, has
<br />readily adapted to favorable habitat. Chan-
<br />nel catfish are abundant in the middle sec-
<br />tions of the study area, becoming rare in
<br />the upper, cooler sections and below Lake
<br />Powell (Table 1). Adults were seldom taken
<br />with conventional collecting gear but were
<br />readily caught on hook and line. They
<br />were very evident surface feeders. During
<br />a large mayfly hatch in Desolation Canyon
<br />August 9, 1968, the surface of the river
<br />was teeming with feeding channel catfish.
<br />The average total length was estimated to
<br />be 15-20 cm.
<br />Age 0 and I catfish were collected by
<br />seine in areas of gentle current and back-
<br />waters. Adults appear to be most common
<br />in eddies but were taken in all habitats.
<br />The largest specimen collected during the
<br />study was 5.9 kg. Fishermen reported
<br />much larger individuals. This species sup-
<br />purts a small fishery in accessible parts of
<br />the study area.
<br />Jordan (1H91) suggested stocking channel
<br />catfIsh in the Colorado River. Miller and
<br />Alcorn (1943) reported that the earliest in-
<br />troductions in thc lower basin wcre ill
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