9490

• UCREFRP Catalog Number: 9490
• Author: U.S. Fish and Wildlife Service.
• Title: Final Environmental Assessment for Procedures for Stocking of Nonnative Fish Species in the Upper Colorado River Basin.
• USFW Year: 1996.
• USFW - Doc Type: Grand Junction.
• Copyright Material: NO

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food resources. Mosquitofish were ranked 8th on the list of 28
nonnative fish species considered to adversely impact the native fishes
in the Colorado River Basin (Hawkins and Nesler 1991).
11. Fathead minnow: Their native distribution is in Central North
America, from the east slope of the Rocky mountains east to the
Appalachian mountains. Commonly introduced as a food source for sport
fish and spread though use as a baitfish in the Colorado River Basin.
Found in a variety of habitats including rivers, lakes, reservoirs, and
ponds. Has been shown to eat larvae of other species, and is also
considered a competitor with young endangered fishes. Fathead minnow
were tied for 5th on the list of 28 nonnative fish species considered
to adversely impact the native fishes in the Colorado River Basin
(Hawkins and Nesler 1991).
12. Cormnon carp: Their native distribution is the temperate regions of
Europe and Asia. Introduced into the Colorado River drainage in the
late 1800's as a food fish. Found in a variety of habitats including
rivers, lakes, reservoirs, and ponds. Eat larvae of other fishes
including Colorado squawfish and razorback sucker. Also competes with
other fishes for food and other resources. Common carp were ranked 4th
on the list of 28 nonnative fish species considered to adversely impact
the native fishes in the Colorado River Basin (Hawkins and Nesler
1991).
13. Smallmouth bass: Their native distribution is in the United States
from the Great Lakes south to the Tennessee River system in Alabama and
west to eastern Oklahoma. This fish has been introduced into the Upper
Colorado River as a sport fish. Escapement from reservoirs in the
Yampa and Green rivers and establishment of a reproducing population in
the Duchesne River has greatly increased the abundance of this species.
Its diet includes other fish. Smallmouth bass were ranked 10th on the
list of 28 nonnative fish species considered to adversely impact the
native fishes in the Colorado River Basin (Hawkins and Nesler 1991).
14. Northern pike: Their native distribution in the United States is
primarily from Nebraska east to the Appalachian Mountains, but also
includes parts of Alaska. This fish was first introduced in the Upper
Colorado River Basin (Elkhead Reservoir, Colorado) in 1977 as a sport
fish. Their habitat ranges from lakes to rivers. Their diet is
primarily other fish. Impacts include predation on and competition
with native fishes. Northern pike were ranked 3rd on the list of 28
nonnative fish species considered to adversely impact the native fishes
in the Colorado River Basin (Hawkins and Nesler 1991).
15. Tiger muskie: Tiger muskie are a hybrid cross between northern
pike and muskellunge. Known as a top predator and introduced as a
sport fish. Diet consists primarily of other fishes. Recently
introduced in the Upper Colorado River Basin in Harvey Gap Reservoir in
Colorado (as a sport fish) and Forsyth and Mill Meadow reservoirs in
Utah (as part of a whirling disease control study; to be removed in
1996). This species does not reproduce and therefore must be
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