WSP11879

• File Number: 8240.200.10.C.5
• Description: UCRBRIP
• Basin: Colorado Mainstem
• Date: 1/1/1993
• Author: USFWS
• Title: Summary of Colorado River Foshes Critical Habitat Briefing
• Water Supply Pro - Doc Type: Publication

11/04/93 16:47 fr
U.S. FISH AND WILDLIFE SERVICE

SEN CAMPBELL

1€l006

.'

Fish & WPdlife Service
For more information cOtltact;
Public Affair$
U.S. Fish and Wildlife Service
Region 6
P.o. Box 25486, DFC
Denver. CO 80225 303.236.7904

Razorback sucker (Xyrauchen eexanus)

3 Feet

Status:
o Listed as endangered by U.S. Fish and WMlife Service in 1991
o Endangered under Colorado law since 1976
oUsted as "protected" in Utah since 1973
o On Arizona list of threatened and endangered speCies since 1975
o listed as rare by California since 1971 "
o listed as rare by Nevade since 1969
o On New Mexico list of threatened and endangered wildlife since 1975
o A recovery plan is in preparation

Deseriotion:
One of the largest suckers in North America. the razorback sucker can grow to more the 13 pounds and lengths
exceeding 3 feet. Tha razorback sucker is brownish-green with e yellOw to white-colored belly and has an
abrupt. bony. keel-edged hump on its back just behind the head. Razorback suckers have been known to live 20.
50 years. This fish is thought to have evolved more that 4 million years ago. R.,zorback sucker stocks consist
predominately of old fish. and they remain in the wild only because of the longevity inherent in this species.

Distribution:
The razorback sucker was once one of the most abundant and widespread fish in the mainstream rivers
throughout most of the Colorado River Basin from Wyoming to Mexico. In the upper Colorado River Basin. it is
now found in the Green River in Utah. the Yamp. River in Colorado. end in Colorado river near Grand Junction.
Colorado. Small populations also exist in the Dirty Devil. San Juan and Colorado River "arms. of Lake Powell.
The largest remaining population of razorback sucker occurs in lake Mohave in the lower Basin. In the lower
Basin, razorbacks have also been found in Lake Mead and the Colorado River. Reintroduction efforts also have
been made in several Arizona tributaries to the Colorado River.

Habitat:
These fish spawn In the spring with rising water levels and increasing temperatures. The fish move into flooded
areas in early spring and then make spawning migrations as they became reprDductively aetive. Depending on
the water temperature and ather environmental cues. spawning ean take place a5 early as November or as late as
June. In nonreproductive periods. adult razorback suckers occupy a variety of habitat types. These include
impounded and riverine areas and habitats represented by : eddies. backwaters. gravel pits. flooded bottomlands,
flooded mouths of tributary streams. slow runs. sandy riffles. and others. After hatching. the young prefer
shallow nearshore habitats and then disperse to deeper water areas as they grow.