8234

• UCREFRP Catalog Number: 8234
• Author: Marsh, P. C. and M. E. Douglas
• Title: Predation by Introduced Fishes on Endangered Humpback Chub and Other Native Species in the Little Colorado River, Arizona
• USFW Year: 1997
• USFW - Doc Type: Transactions of the American Fisheries Society
• Copyright Material: YES

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Young-of-year and older juvenile bluehead suckers
dominated seine samples from the White River
from 1983 to 1985 (Martinez, Chart 1987); seining
was also the principle means of sampling fish in the
river in 1989-1990 (Trammell 1991).
While evidence is lacking to show roundtail chub
and flannelmouth sucker benefitted from impound-
ment of the White River, neither should be as ad-
versely affected as bluehead sucker and speckled
dace. Roundtail chubs and flannelmouth suckers
continued to be commonly collected in Kenney
Reservoir, although their abundance relative to
numbers of non-native fishes was low. Behnke' pre-
dicted roundtail chub would increase following im-
poundment. Chart (1987) suggested roundtail chub,
unless replaced by further introductions of non-na-
tive species, could flourish in Kenney Reservoir.
Chart & Bergersen (1992) indicated Taylor Draw
Dam would not affect flannelmouth suckers in the
White River due to their distribution and move-
ment patterns. Both roundtail chub and flannel-
mouth sucker occur in reservoirs (Baxter & Simon
1970); both occur in Elkhead Reservoir, an off-stem
impoundment in the Yampa River drainage where
their persistence indicates recruitment has oc-
curred (Martinez unpublished data).
Mountain whitefish and mottled sculpin inhabit
the White River, primarily upstream of Kenney
Reservoir (Tyus et al. 1982). Immediate effects of
impoundment on these species appeared negligible
and significant delayed effects are not expected.
Consequences of non-native fishes
Lanigan & Berry (1981) suggested native fishes in
the White River in Utah were being replaced by
non-native species. They believed habitat deterio-
ration and competition were operative in the lower
White River, and were responsible for a pattern of
native fish displacement in other western rivers and
streams. While they demonstrated the relative
abundance of native fishes was greater than that of
non-native species in their uppermost stations near-
s Behnke, R.J. 1981. Taylor Draw Reservoir: aquatic biology as-
sessment. Western Engineers Inc.. Grand Junction. 16 pp.
est to Colorado. non-native species accounted for
80.4% of the fish collected in their middle and lower
stations (Lanigan & Berry 1981). Replacement of
the predominantly native ichthyofauna by non-na-
tive fishes in the lower White River in Colorado was
facilitated and certainly greatly accelerated by con-
struction of Kenney Reservoir. Relative abundance
of non-native species in the White River below Tay-
lor Draw Dam in 1989 and 1990 averaged 79.4%;
thus, in less than a decade, the riverine ichthyofau-
na of the lower White River in Colorado has shifted
from 90% native to 80% non-native species.
All non-native fish species recorded during this
study were formerly known to occur in the White
river drainage, either upstream or downstream of
the study site or in Rio Blanco Lake. a shallow, off-
stem impoundment at RK 243 (Fig. 1) managed for
warmwater sport fishes. Nesler listed six non-na-
tive species posing the greatest threat to native fish-
es in the upper Colorado River basin: red shiner,
common carp, fathead minnow, channel catfish,
northern pike, and green sunfish. In addition,
McConnell et al.3 predicted Kenney Reservoir
would provide highly suitable habitat for common
carp, white sucker and black crappie. While non-na-
tive species collected during this investigation, ex-
cept largemouth bass, had been previously reported
from the White River (Tyus et al. 1982. Martinez),
none were formerly dominant in the river in Col-
orado.
Red shiner was reported by Lanigan & Berry
(1981) and Miller et al.' to be the most abundant fish
from their lowermost stations in the White River.
Utah. The combined percentage for red shiner in
these stations was about 66% in 1978 and 1979 (La-
nigan & Berry 1981) and 1981 (Miller et al.). For-
merly composing much lower percentages in the
White River in Colorado prior to impoundment
(Carlson et al', Miller et al'), red shiner accounted
for about 47% of all fishes collected in 1989 and
1990. It appears the segment of the White River in
which red shiners dominate has increased bv_ more
than 50% since impoundment.
Common carp and fathead minnow were rare in
the White River in Colorado prior to formation of
Kenney Reservoir (Tyus et al. 1982). Carlson et al.'
and Miller et al! showed neither species accounted