7147

• UCREFRP Catalog Number: 7147
• Author: Holden, P. B. and C. B. Stalnaker
• Title: Distribution and Abundance of Mainstream Fishes of the Middle and Upper Colorado River Basins, 1967-1973
• USFW Year: 1975
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: YES

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222 TRANS. AMER. FISH. SOc., 1975, NO. 2
TABLE 2.-Number of adult fiJh taken in the Colorado River system above Lake Mead 1967-1973 primarily
with gill nets and electrofishing gear
Species 1967 1968 1969 1970 1971 Total
Salmonidae
I Salma gairdneri 3 7 24 many >34
SalIna trulta 0 15 7 2 24
Salma clarki 2 0 6 0 8
Prosopium williamsoni 1 0 1 many >2
Cyprinidae
Gilu rabus/a 180 105 60 30 375
Gila elegum 29 3 4 0 36
Gila cypha complex 22 6 26 6 1 61
PtycllOcheilu.s lucius 71 90 127 12 300
Caloslomidae
CalostoTnl1S latipinnl:s 1983 1709 2400 many > 6092
Catoslomns discobolus 479 276 318 many >1073
Catostomus commersoni 5 6 39 many >50
Xyrauchen texanu.s 6 4 33 10 53
Cenlrarchidae
M icropterus salmoides 0 0 1 0 1
Lepomis m{lCrOch,~rHs 0 1 0 0 1
Lcpomis cyanetlus 1 1 0 5 7
Pcrciuae
Stizostedion vitreum 0 4 4 0 8
Hybrids
Gatasia/nus [alipinnis X
Xyrauchen texanllS 5 6 27 2 40
Catostofllus discobo/us X
CalostomllS commer.50ni 4 3 many >8
Catoslomlis lalipinnis X
Calo.~lomllS commersoni 0 9 several >10

McDonald and Dotson (1960) and Sigler
and Miller (1963). The original introduction
was probably as released baitfish. This
species, so often a pest fish, apparently
has not found suitable conditions in the
study area. They arc ilourishing in Flaming
Gorge Reservoir.
Roundlail chub-Gila rolmsta Baird and
Girard. Historically, the roulldlaiJ chub has
been the dominant native carnivore of
tributaries in the Colorado basin. It is
abundant in. areas 1, 2, 3, 9, and 10, but
diminishes rather rapidly downstream from
these areas in both the Green and Col-
orado Hivers. Tltis general type of distribu-
tion was noted by Jordan and Evermann
(1896) as they reported roundtail to Ihe
"base of the mountains" in the Gunnison
River. The round tail was also alHlndant in
major trihutaries such as Little Snake,
Duchesne, White, Price, and Dolores. It
was collected from all habitats, riff1es to
stagnant backwaters. LiuJe change in his-
toric distribution and abundance was
noted.

Bony tail chub-Gila elegans Baird and
Girard. The endemic bony tail chub is very
rare in the Colorado basin. It was col-
lected in areas 2, 3, 4, and 5; only 36 were
taken. Historically, it was found in the
main channels of livers below the range of
the ronndtail chub (Jordan and Evermann
UN6). Vanicek and Kramer (1969) calcu-
lated strong year classes of bony tail chuh
for 1959, 1960, and 1961 in area 3 from
adults collected in 1964-66. A search
through samples of several hundred young
chubs collected in area 3 by V,lI1icek and
Kramer and during the present study re-
vealed only three: possible bony tail chubs.
This scarcit y suggests t hat for the last sev-
eral years h(Hlvtail chuhs have not repro-
duccd well where they were once success-
ful. Also, the concomitant dccrease in
adult numbers suggests this species is
rapidly losing ground in an area where: it
was recenlly abundant. The period of de-
crease corresponds to the time Flaming
Gorge Dam has heen closed.
Bony tail chuhs were apparently once

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