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

A detailed description of the Recovery Program is provided by the U.S.
Fish and Wildlife Service (1987a), an environmental assessment of its
implementation is provided by the U.S. Fish and Wildlife Service
(1987b), and its evolution along with pertinent background is summarized
by Wydoski and Hamill (1991).
The Recovery Program consists of five major elements for recovery of
endangered fishes in the Upper Colorado River Basin: (1) provision of
in-stream flows; (2) habitat development and maintenance; (3) native
fish stocking; (4) management of nonnative species and sport fishing;
and (5) research, monitoring, and data management (U.S. Fish and
Wildlife Service 1987a, 1987b).
Representatives of the cooperating agencies and organizations serve on --
several committees to oversee the Recovery Program within the framework
of the Endangered Species Act, existing states' water rights, and terms
of the Colorado River compacts (Rose and Hamill 1988). All decisions
by the Recovery Program participants are made on the best available
information and refined as new information becomes available using the
adaptive management approach (Walters and Hillborn 1978; Walters 1986).
2. Recoverv Issue Discussed in this Draft Environmental Assessment. Human
alteration of the Upper Colorado River and its tributaries had a major
negative impact on some of the native fishes -- to the point where they
are now listed as endangered. Some of the native fishes, adapted to the
highly variable aquatic environment of the natural ecosystem, are still
able to maintain self-sustaining. populations, despite the drastic
altered state of the present river environment. In less altered river
reaches, native-fish species dominate the fish fauna (Anderson 1997;
Burdick 1995) while, in more altered reaches, nonnative fish species are
more successful (Miller et al. 1982; Tyus et al. 1982).
(A) Introduction of Nonnative Fishes in the Upper Colorado River Basin
and Impacts on Native Fishes The introduction of fish species
not native to the Colorado River Basin began in the late 1800's.
Such introductions occurred for a variety of reasons including
establishment of sport fish populations, forage for the sport fish
species, biological control of unwanted pests, aesthetic or
ornamental purposes, release of unwanted pets or bait fish, and
accidental releases (Taylor et al. 1984). Some of these
introductions were not successful in becoming established while
other introductions resulted in establishing self-sustaining
populations in various parts of the Upper Colorado River Basin.
The species composition of a fish community can be altered
dramatically and quickly. For example, pre-impoundment
investigations of Taylor Draw Dam on the White River, Colorado in
1983-1984 was dominated (97%) by native fishes above, within, and
below the reservoir basin. By 1989-1990, nonnative fishes
comprised 90% of the fishes collected in the reservoir and 80% of
the fishes collected in the river below the dam (Martinez et al.
1994). Generally, the successful nonnative fishes expanded their
ranges throughout the Upper Basin wherever habitats were suitable