7400

• UCREFRP Catalog Number: 7400
• Author: Valdez, R. A.
• Title: The Endangered Fish of Cataract Canyon
• USFW Year: 1990.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

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The three endangered species (Colorado squawfish, humpback chub, bonytaiij were present in low
numbers during each year of the investigation (Table 6). From 1985 to 1988, 4348 Colorado squawfish,
108 humpback chub, and 14 suspected bonytail were captured. Only one razorback sucker (a federal
candidate for listing) was found in 1988. These four species accounted for less than 6% of the fish
captured in any given year of the study.

When all fish were summarized by year, five non-native species consistently made up most of the
catch (Table 7). These included the red shiner, sand shiner, channel catfish, carp, and fathead minnow.
Except for 1986, red shiners made up over 50% of the catch in all years. Relative numbers of all non-
native cyprinids were down in 1986, indicating poor year classes of these species during the record
runoff years of 1984 and 1985 (See Section 4.2.5).

Table 6. Numbers of endangered fish by species and age category captured by year, 1985-1988.
SPECIES YEAR
AGE 1985 1986 1987 1988 TOTAL
Colorado Squawflsh
LAR 156 91 111 27 385
yay 357 606 834 1979 3n6
JUV 4 48 69 54 175
ADU ~ ~ ---2 ---2 ~
TOTAL 521 749 1016 2062 4348
Humpback Chub
LAR 1 8 0 2 11
YOY 7 4 4 4 19
JUV 1 2 11 42 56
ADU ..,g ~ ....2 ...11 22
TOTAL 11 17 21 59 108
Bonytall (suspected)
LAR 0 0 0 0 0
YOY 1 0 0 0 1
JUV 0 0 1 6 7
ADU ...1 ...1 ...1 ~ ....2
TOTAL 2 1 2 10 14
Razorback Sucker
LAR 0 0 0 0 0
YOY 0 0 0 0 0
JUV 0 0 0 0 0
ADU ...Q ...Q ...1 ...Q ...1
TOTAL 0 0 1 0 1
GRAND TOTALS 534 767 1040 2131 4471

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