8215

• UCREFRP Catalog Number: 8215
• Author: U.S. Fish and Wildlife Service.
• Title: Final Environmental Assessment
• USFW Year: 1997.
• USFW - Doc Type: Management and Control of Noonative Fish Species in Floodplain Ponds of the Upper Colorado and Gunnison Rivers.
• Copyright Material: NO

Nonnative fishes compose 76% of the fish species (42 of 55 species) in the
riverine environment of the Upper Colorado River Basin (Tyus et al. 1982).
These nonnative fishes constitute most of the fish numbers (96.7 - 99.6%)
found in backwater habitats in the Upper Basin (Cranney 1994; McAda et al.
1994a,b; 1995; 1997). Researchers and other participants in the Recovery
Program agree that predation and competition by established, self-sustaining
populations of nonnative fishes and chronic escapement of nonnative fishes
from off-channel ponds and impoundments are factors that increase mortality
of the endangered fishes (Lensch et al. 1995; Tyus and Saunders 1996). They
further agreed that action to control nonnative fishes was needed
immediately.
The specific purpose of this environmental assessment is to evaluate
alternatives for management and control of nonnative fish species that will
reduce, minimize, and/or eliminate chronic escapement of nonnative fish
species from floodplain ponds along the Upper Colorado and Gunnison rivers ___
(Figure 1). The project area (Upper Colorado River from the Colorado-Utah
state line upstream to Rifle, Colorado and the Gunnison River from the
confluence of the Colorado River upstream to Delta, Colorado) includes the
critical habitat of the Colorado squawfish and razorback sucker (Maddux et
al. 1993). Five alternatives to achieve this goal ire considered in this
environmental assessment including the mechanical and/or chemical control
of nonnative fish species from floodplain ponds.
This draft Environmental Assessment (EA) was prepared by the U.S. Fish and
Wildlife Service (Service} in compliance with the National Environmental
Policy Act of 1969 (NEPA; 42 U.S.C. Sections 4321-4361), Endangered Species
Act of 1973 (16 U.S.C. 1531 et seq.), and related U.S. Department of the
Interior mandates, regulations, and policies. This EA was used by the
Division of Ecological Services, U.S. Fish and Wildlife Service, as the
basis for writing a biological opinion related to Section 7 of the
Endangered Species Act through an intraservice consultation. This document
will also be used to determine (1) if the proposed action is a major federal
action that significantly affects the environment and (2) if an
Environmental Impact Statement is necessary under NEPA.
C. Need. The alteration of natural fish communities through introductions of
nonnative fish species has resulted in reductions of numerous native fishes
throughout North America (Courtenay 1993; Li and Moyle 1993; Meffe 1985;
Matthews and Heiss 1987; Moyle et al. 1986; Scoppettone 1993; Taylor et al.
1984). About three-fourths of the 40 North American fish species that
became extinct during the past century were related to two factors: (1)
alteration of physical habitat - 73% and (2) detrimental effects of
introduced fishes - 68% (Miller et al. 1989).
Some of the nonnative fish species were introduced into the Upper Colorado
River Basin to provide sportfishing opportunities. Biologists from state
and federal agencies worked cooperatively to develop "Procedures for
Stocking Nonnative Fish Species in the Upper Colorado River Basin" (Colorado
Division of Wildlife et al. 1996). The intent of these Procedures is to
allow stocking of nonnative fish species for warmwater sportfishing