7047

• UCREFRP Catalog Number: 7047
• Author: Tyus, H. M. and C. A. Karp.
• Title: Habitat Use and Streamflow Needs of Rare and Endangered Fishes in the Green River, Utah
• USFW Year: 1991.
• USFW - Doc Type: Final Report.
• Copyright Material: NO

(including lower flows) or other conditions (e.g. temperature and fish
movements) which may favor growth and reproduction of channel catfish in the
Green River basin should be further evaluated.
Bonytail Chub
Habitat requirements of the bonytail chub in the Green River basin are
little known. Fish collections in Echo Park (DNM) before and after closure of
Flaming Gorge Dam indicated that the species was present in moderate numbers
at the confluence of Yampa and Green rivers (Vanicek 1967). However, more
recent investigations in that area have yielded few captures. Holden and
Stalnaker (1975) reported the capture of 36 bonytail chubs in Yampa (lower 16
km) and upper Green rivers from 1968 to 1970. Holden and Crist (1981)
collected one bonytail chub in the lower Yampa River in 1979, and USFWS
biologists captured one suspected juvenile in 1987. Preliminary results of a
radiotracking study of adult bonytail chub introduced into the upper Green
River in 1988 and 1989 indicate that the fish exhibit crepuscular movements,
and are relatively quiescent during the day and night (S. Cranney, Utah
Division of Wildlife Resources, pers. comm.).
Bonytail chub have apparently declined in the Echo Park area, possibly
due to habitat changes resulting from closure of Flaming Gorge Dam. These
changes included alteration of flow and temperature patterns, and also a
reduction in the number of macroinvertebrate taxa (Pearson 1967), i.e., the
food base. A similar pattern has been noted in the Colorado River downstream
from Glen Canyon Dam (Utah State Department Fish and Game 1964, 1969).
Although the preimpoundment poisoning of riverine habitat in the upper Green
River in 1962 has been implicated in the decline of the bonytail chub in that
system, fish collections in DNM before and after the poisoning (Binns et al.
1963; Vanicek and Kramer 1969; Vanicek et al. 1970) suggested that the
downstream extent of the poison was not the only factor in the extirpation of
the species from the Echo Park area. Flaming Gorge Dam operations could affect
the future of bonytail chub re-introductions in the Green River system, and
these operations must be considered in future reintroduction efforts.
Razorback Sucker
Adult razorback suckers have been predominantly captured in the upper
Green River (km 282 - 552) and in the lower 21 km of the Yampa River (Azevedo
1962; Vanicek et al. 1970; Holden and Stalnaker 1975; Seethaler et al. 1979;
McAda and Wydowski 1980; Miller et al. 1982a; Tyus et al. 1982b; Tyus 1987;
Tyus and Karp 1990). Catch-effort estimates indicate that adult razorback
suckers are more rare than other native suckers and the endangered Colorado
squawfish (Table 1).
Radiotagged razorback suckers overwintered in the Jensen, and Island and
Echo parks reaches of Green River (McAda and Wydowski 1980; Valdez and
Masslich 1989). In winter, razorback suckers used slow runs, slackwaters,
eddies and backwaters in the Green River, where local movements increased
with increased discharge and flow fluctuations (Valdez and Masslich 1989).
Razorback suckers have been observed using large backwaters in the Ouray area
of the Green River during early spring (HMT).
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