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

C. Fish and Wildlife Resources. Conspicuous and dominant wildlife species in
floodplain areas of the Colorado and Gunnison rivers include the Canada
goose (Branta canadensis), great blue heron (Ardea colchicus), various
species of dabbling and diving ducks, various shorebirds, muskrats (Ondatra
zibethicus), and northern leopard frog (Rana i~'piens). Various passerine
birds migrate through or nest in the project area. The species of birds
that inhabit the riparian zone in the floodplains of both rivers are too
numerous to list individually. Refer to the checklist of bird species for
Mesa County in Appendix A. Similar species would also occupy the riparian
zone in Delta and Garfield Counties.
Thirty or more birds that feed on fish use floodplain ponds for feeding
(Appendix B). These birds include aquatic diving birds (e.g., grebes and
mergansers), wading birds (e.g., various herons and egrets), and aerial
diving birds (e.g. osprey, bald eagle, and belted kingfisher).
Fish resources include the native flannelmouth sucker (Catostomus
latipinnis), bluehead sucker (Catostomus discobolus), and roundtail chub
(Gila robusta). Introduced fish species include channel catfish (Ictalurus
punctatus), black bullhead (Ictalurus melas), common carp (Cyprinus car io),
fathead minnow (Pimephales promelas), red shiner (Notropis lutrensis), white
sucker (Catostomus commersoni), and green sunfish (Leaomis cvanellus).
Pond owners along the Colorado River reported that 32% of the ponds
contained fish while pond owners along the Gunnison River reported that 10%
of the ponds contained fish (Mitchell 1995). Ponds containing nonnative,
warmwater fishes were dominated by largemouth bass (Micropterus salmoides}.
Other nonnative, warmwater fish species in the ponds included bluegill
(Lepomis macrochirus), black crappie (Pomoxis nigromaculatus), catfish
(Ictalurus sp.), common carp, fathead minnow, suckers, rainbow trout
(Oncorhynchus garidneri), brown trout (Salmo trutta), brook trout
(Salvelinus fontinalis), and triploid grass carp (Ctenopharongodon idella).
Surveys of private ponds in the floodplain of the Colorado River by the
Colorado Division of Wildlife generally contained common carp, black
bullhead, white sucker, and fathead minnow (W. Elmblad, 1995, Personal
Communication) while public ponds contained warmwater sportfish species such
as largemouth bass, bluegill, and black crappie (P. Martinez, 1997, Personal
Communication).
Traditionally, wetlands such as those in floodplain ponds were considered
to be compatible between fish and birds with the exception of the common
carp (Johnson 1964; Poff 1985). However, this assumption is often incorrect
based on the literature. Observational and experimental studies have
demonstrated that fish can dramatically restructure wetland food webs
(Bouffard and Hanson 1997). Fish predation reduces the abundance and mean
size of benthic and littoral invertebrates used as food by birds (Murdock
and Bence 1987) and has been suggested to be the major determinant in the
assemblages of aquatic invertebrates (Bendell and McNichol 1987).
D. Endangered Saecies. Endangered species that occur in Colorado are
summarized in Appendix C (U.S. Fish and Wildlife Service 1997). Endangered
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