7338

• UCREFRP Catalog Number: 7338
• Author: Valdez, R. A. and R. D. Williams
• Title: Endangered Fishes of Cataract Canyon
• USFW Year: 1986
• USFW - Doc Type: Desert Fishes Council
• Copyright Material: YES

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Table 1. A list of fish species and rmmbers captured in the region of Cataract
Canyon during six 8-day trips fran July 11 t:o October 6, 1986.

SPECIFS NATIVE

NON-NATIVE

NlM3ER

PEHCENTAGE

Sand shiner
Red shiner
Channel catfish
Fathead minnow X
carp
COlorado sc:pawf ish X
Flannelmout:h sucker X
Speckled dace X
Rcundtai 1 chub X
fllmptack chub X
Ganbusia
Bluehead sucker X
Gila sp.
Largemouth tsss
Black l:nllhead
Green sunfish
W:llleye
Plains killf ish
St:riped bass
Black c:ra.wie
Nrl t:e sucker
Norb.'1ern pika
Brown trout
Slnallmout:h tass

X
X
X

X

3411
3291
1891
1162
1118
505
116
104
11
33
29
23
11
14
13
12
1
5
2
2
2
1
1
1

29.0
21.6
15.9
9.7
9.3
4.2
1.5
0.9
0.6
0.3
0.2
0.2
0.1
0.1
0.1
0.1
0.1
<0.1
<0.1
<0.1
<0.1
<0.1
<0.1
<0.1

X

X
X
X
X
X
X
X
X
X
X
X

Of t:he 23 species, 16 are non-native and only 7 are nat:ive. As a
percentage of total catch, the ratio of non-nat:ive to native fishes was 82.5 t:o
11 .5. The endangered species (COlorado squawfish, 4.2% and lumpback, 0.3%) made
up 4. fi% of the t:otal cat:ch. Bonytai 1 and razorl:ack sucker lEre not:' captured in
Cataract Canyon in 1986.

COlora:'1o SQuawfish

A t:ot:al of 505 Colorado squawfish were captured during this 1986
investigation, including 456 ycung of the year (YOY), 44 juveniles, aoo 5 aiul ts
(Table 2). Of the 5 aiul ts captured, two had been previously ta91ed by the ~
in the Green River about 112 and 120 miles upstream 3 years before. as wit:h
1985, the majority of the YOY squawfish \<ere captured on t:he Green River, al:x:Jve
the COlorado River confluence. The majority of juveniles captured belcmged t:o
the 1985 year class. n.:mty of the 44 juveniles were found. in large isolated

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