8135

• UCREFRP Catalog Number: 8135
• Author: Valdez, R. A.
• Title: Occurrence of Threatened and Endangered Fishes of the Colorado River in the Vicinity of the Proposed Jacobson Hydro No. 1 Project.
• USFW Year: 1984.
• USFW - Doc Type: Logan, Utah.
• Copyright Material: NO

5-1

5.0 RESULTS

5.1 Species Composition
A total of 14 fish species, 3 hybrids or intergrades, and 1 unknown
(not believed to be a T&E fish) were captured within the 5.4-mile study
reach of the Upper Colorado River. A summary of fish capture information
for the four gear types is presented in Tables B-1 through B-3 in Appendix
B. A breakdown of the percentage composition by species for the four gear
types, separately and combined, is presented in Figure 2. Details on
numbers of fishes by species for each gear type are provided in Table B-4.
The 14 species represent the following 6 families with the respective
number of species in each: Catostomidae (3), Centrarchidae (2), Cottidae(l},
Cyprinidae(5}, Ictaluridae(l}, and Salmonidae (2). Table B-5 presents a
breakdown of the species by family, the species codes used in this report,
and the status of each species in the Upper Colorado River.
Of the 14 species captured, only 5 (bluehead sucker, flannelmouth
sucker, mottled sculpin, roundtail chub, and speckled dace) were either
native or endemic to the Colorado River Basin. The remaining 9 species were
introduced and are classified as either nonnative or exotic (see Table B-5
for definitions). Of the 14 species, only 3 (largemouth bass, brown trout,
and rainbow trout) are classified as sport fishes with bag limits by the
State of Colorado. Similar findings by Valdez et. al (1982) and Valdez and
Carter (1983) in river reaches above the JH-1 study reach indicate that the
current study yielded an accurate representation of the fishes present. No
fishes classified as either threatened or endangered, or candidate or
proposed by either the State of Colorado or the United States Department of
Interior were captured or observed. The five specimens of the intergrade of
the Gila complex (~cypha x G. robusta) that were captured during this