9553

• UCREFRP Catalog Number: 9553
• Author: Valdez, R. A. and R. T. Muth
• Title: Ecology and Conservation of Native Fishes in the Upper Colorado River Basin
• USFW Year: 2005
• USFW - Doc Type: American Fisheries Society Symposium
• Copyright Material: YES

ECOLOGY AND CONSERVATION OF NATIVE FISHES IN THE UPPER COLORADO RlVER BASIN

161

Table I.-Continued.

Status"

Distribution and abundance

Species

Colorado River cutthroat trout
Oncorhynchus clarkii pleuriticus

Co-CO,
UT,WY
Sf-CO

Small local populations in high elevation streams

a EN = federally endangered; status by indicated state: En = endangered, Ex = extirpated, Th = threatened, Sp =
species of special concern or sensitive species, Co = conservation species; Sf = sport fish.

determined from scale annuli, is up to 18 years
(Vanicek and Kramer 1969; Seethaler 1978;
Musker 1981; Hawkins 1992). However, Os-
mundson et al. (1997) cautioned that scale-based
estimations are probably unreliable for Colorado
pikeminnow beyond about age 10, and concluded
that growth-rate data indicated that large fish (e.g.,
more than 900 mm TL) averaged 47-55 years old
with a minimum of 34 years. Growth and size in
the upper basin appear limited by colder tempera-
tures and a shorter growing season (Kaeding and
Osmundson 1989). The species was listed as en-
dangered in 1967 (32 FR 4001), and protected
by the ESA in 1973 (39 FR 1175), with critical
habitat designated in 1994 (59 FR 13374). A re-
covery plan was approved in 1978 (U.S. Fish and

Wildlife Service 1978), revised in 1991 (U.S. Fish
and Wildlife Service 1991), and amended and
supplemented with recovery goals in 2002 (U.S.
Fish and Wildlife Service 2002a). As for hump-
back chub, bony tail, and razorback sucker, these
recovery goals provide demographic criteria and
management actions to minimize or remove threats.
Colorado pikeminnow is endemic to the Colo-
rado River system, and was once widespread and
abundant in warm main-stem rivers and tributaries
(Kirsch 1889; Evermann and Rutter 1895; Jordan
and Evermann 1896; Banks 1964; Vanicek 1967;
Holden and Stalnaker 1975a; Holden and Wick
1982;Tyus 1991; Quartarone 1995). In the upper
basin, the species was first reported in 1825 by Colo-
nel William H. Ashley (Morgan 1964; Seethaler

Figure 3.-Adult Colorado pikeminnow captured in the Redlands fish passage on the Gunnison River in 2002,
approximate weight 12 kg. Photo courtesy of Bob Burdick, U.S. Fish and Wildlife Service.