WSP07668

• File Number: 8240.200.10.C.5
• Description: UCRBRIP
• Basin: Colorado Mainstem
• Date: 3/21/1994
• Author: USFWS
• Title: Federal Register - Determination of Critical Habitat for Four Colorado River Endangered Fishes - Final Rule
• Water Supply Pro - Doc Type: Publication

13376

Federal Register / Vel. 59, No. 54 / Monday, March 21, 199~ / Ru.ies and Regulations

ephemeral aloIlg-share embayments that
develop as spring flows <lecline.
Humpback Chub
Remains of h11II1phack <:hub have been
found in archaeological sites dared to
ahout4000 ltC, (USFWS 1990b). This
Colorado River native fish was not
described as a species until 1945 {MUler
1946). This has been attributed to its
presently restricted distribution in
remote. white water canyons [USFWS
1990b). The historical abundance and
distribution of the. species is not well
known. In the Lower Basin, the
humpback chub occurs in the Uttle
Colorado and Colorado Rivers in the
Grand Canyon. This population is the
largest remaining in the Basin, In the
Upper Basin, humpback chub an> fO\Uld
in the Black RockslWestwater Canyon
and .Cataract Canyon of the Colorado
River, Desolation and Gray Canyons of
the Green River, and Yampa and
Whirlpool Canyons in Dinosaur
National Monument, Green and Yampa
Rivers (USFW5'199Ob). . .
Hwnpback chub in reproductive
condition an> usually captured in May,
June, or July, depending on location.
SpBWDing 00ClUS soon after the highest
spring f1owsw\1en water temp.adtw_
approadt 1.C"C (6Il" FJ (Karp and Tyus
1990; USFWS 19901>). The importance
of sprillg flows and propeo- tempemtures
for hU1u~chub is stressed by
Kaeding aDd 7;........man (1983). who
implicated.60w:reductions and low
...;ater tempel8lm'eS in the Gland Canyon
as factprs ~ wccessful. .m ..
spawning of the fish and increas:mg
competition from other species.
Popnlsrlnn< m Iu.unpi>lick chub are
found in_canyons, wilere they
utilize a variety of habitats, including
pools, riffles. and eddies- Most of the .
existing iDb:mation on habitat
prefenmoes ilasbeen obtained from
adultfish in the Little Colorado River,
the Grand Oany<>n. and the Black Rocks
of the Colorado Ri_(Holden and
Stalnaker 1975;'Kaeding and
Zimmerman 1983; Kaeding et at 1990).
In these locations. the fish are found
associated with boulder-strewn
canyons. travertine dams, pools, and
eddies. Some .habitat-use data also are
available from the Yampa River Canyon
where the fish occapy similai- habitats
and also use r!lCky runs, riffles, rapids.
and shoreline eddies (KaIp and Tyus
1990), This -diversity in habitat use
suggests that the adult fish are adal'ted
to a variety of habitats. and studies of
tagged fish'indicated that they move
between habitats. presumably in
. response oo....-l habitat changes
aI,d life history needs (Kaeding and
Zimmerman 1983; Karp and Tyus 1990).

Reduced spring peak flows- availability
of shoreline eddy and deel' canyon
habitats. and competition and predation
by nonnative fish were reported as
potential Jhnitillg factors ror humpback
chub in the YampaRiver{Tyus and
Karp 1989). The impact of hybridization
with other specieS is currently being
evaluated.

Bonytail Chub

The bonytail chnb (also known as the
bonytail) is the mrest native fish in the
Basin. Historically reported as
widespread and abundant in rivers
.throughoutthe Basin ijordanJlJ1d
Evermann 1896), its populations have
been greatly reduced. The fishis
presently represented in the wild by a
low number of old fish 4. ages of 40
years or mQl'e), and recnrltment is
virtually nonexistent. In the Lower
Basin. a small population pemists in the
Colorado Rivet in Lake Monave, and
there an> recent records from Lake
Havasu lUSFWS 1990a).ln the Upper
Basin. recent captures have been from
Dinosaur Natiorial Monument on the
Yampa River, Desolation and Gray
Canyons on the Green River. and Black
Rocks and Cataract Canyon on .the
ColDrado River {Kaeding et at 1985;
. Tyus et al. 1987; Valdez 1990; USl'WS
1990a).
Thebonytrll chub is adapted to
mainstream rivers. where it has been
abseIVed in pools and eddies ~ckley
1973; Vanicek 1967), In reservoirs, the
fish occupies a variety ofhilhitat types
(Minckley 1973). In Lake Mohave.
Wagner {1955) observed the fish in eddy
habitats. Spawning reqnirements have
never been do=ented in a river. but
Vanicek and KIamer {1969) reported
that spawning occurred in June and Jnly
at water temperatures of about 11l" C
(54" F). The available data suggest1hat
habitats required for conservation of the
bonytail chub include, river channels,
and flooded, ponded, or inundated
riverine habitats that would be 'SUitable
for adults and young, especially if
competition from nonnative fishes is
. reduced (USFWS 1990a).

Previous Federal Acti0D5

Listing Chronology

The Colorado squawfish and
humpback chub _re listed as
endangered species on March 11. 1987
(32 FR 4001) and the bonytail chub was
listed as endangered on April 23, 1980
{45 FR 27713~ Critical habitat for these
species was llOt <Iesignated at the time
of their listing. On May lS, 1975, the
Service published a notice of its intant
to determine critical habitat for the
ColDrado squawfish and the humpback

chub, and other species (4ll FR 21499).
On September 14, 1978. the Service'
proposed 1.002 lan (623 mil of the
Colorado. Green, Gunnison. and Yampa
RiveIS as critical habitat for the
Colorado squawfish (43 FR 41000). The
proposal was for 1.oo2lan (623 mij of
the Colorado, Green" Gunnison, and
Yampa RiYers. This proposal was later
withdrawn {44 FR 12382; March 6,
1979) to comp.lywith the 1978
amendments to the Act {IS U.S,c. 1531
el seq.).
The razori>ack sucker was fust
proposed for listing as a threatened
species on April 24, 1978 (43 FR 17375).
The proposal was withdrawn on Mll)'
27. 1980 (45 FR 35410).00 comply with
provisions of the 1978 amendments to
the Act. These prorisioos required the
Service to include considemlion of
designating critical habitat in the listing
of species, to complete the listing
process within 2 yaars from the date of
the proposed nile. 0< wilhdraw the
proposal from further consideration.
The Service did not complete the listing
process within the 2-year deadline.
On March 15, 1.989. the Sem.oe
received a petition from the Sieml Club.
National Audubon SociBty. The
Wilderness Society, Coiorado .
Enviroo.meni.al CoaJitioD"SoulliemUtah
Wiklemess Alliance, and Northwest
Rivers Alliance to list the razorback
sucl<er 8S endangered. The Service made
a positive ii:odiog in June 1989 and
subsequently published 8 llDlice in the
Federal ~.on August 15. 1989 {54
FR 33566). This notlce also slated that
the Service W/IS completing a status
remw JlJ1d ..... seeking additiollal
information until Decembe< 15, 1989. A
proposed rule to list the <azorback
sucker as eIldm1gered was published in
the FederalllAogister on May 22, 1990
(55 FR 21154).
The &a1 rule listing the razorback
sucker as an ewlangered species was
published on October 23,1991 j56 FR
54957). hut critical habitat waSllOt
proposed. In the final rule. the Seryice
concluded tha1 critical habitat was not
determinable at the time of listing and
questioned whether it was prudent to
designate critical habitat.
On October 30, 1991. the Service
received a 6O-day notice of Intent to sue
from the Sierra Club Legal DeieDse
Fund. The subject of the notice was the
Service's failiL.;" to designate critical
habitat concurrent wilh listing of the
razorback sucker pursuant to section
4lb)j6)(c) of the Act. The Sierra Club
Legal Defense Fund followed this with
a second notice of intent to sue dated
January 30,1992. Ata meeting on
December 5. 1991, the Service
concluded that designatioll of critical