[Federal Register: April 20, 2004 (Volume 69, Number 76)]
[Page 21151-21158]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]



Fish and Wildlife Service

Endangered and Threatened Wildlife and Plants; 90-Day Finding on 
a Petition To List the Colorado River Cutthroat Trout

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 90-day petition finding.


SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
90-day finding for a petition to list the Colorado River cutthroat 
trout (CRCT) (Oncorhynchus clarki pleuriticus) as threatened or 
endangered under the Endangered Species Act of 1973, as amended. We 
find the petition and additional information available in our files did 
not present substantial scientific or commercial information indicating 
that listing this subspecies may be warranted. We will not be 
initiating a further status review in response to this petition. We ask 
the public to submit to us any new information that becomes available 
concerning the status of or threats to the species. This information 
will help us monitor and encourage the conservation of this species.

DATES: The finding announced in this document was made on April 8, 
2004. You may submit new information concerning this species for our 
consideration at any time.

ADDRESSES: Information, data, or comments concerning this finding 
should be submitted to the Assistant Field Supervisor, Ecological 
Services, U.S. Fish and Wildlife Service, 764 Horizon Drive, Building 
B, Grand Junction, Colorado 81506, or by e-mail to al_pfister@fws.gov. 
The petition, finding, supporting data, and comments are available for 
public inspection, by appointment, during normal business hours, at the 
above address.

FOR FURTHER INFORMATION CONTACT: Patty Schrader Gelatt, at the above 
address, by telephone at 970-243-2778, or by e-mail at 



    Section 4(b)(3)(A) of the Endangered Species Act of 1973, as 
amended (16 U.S.C. 1531 et seq.) (ESA), requires that within 90 days of 
receipt of a petition, to the maximum extent practicable, we make a 
finding on whether a petition to list, delist, or reclassify a species 
presents substantial scientific or commercial information indicating 
that the requested action may be warranted. The term ``species'' 
includes any subspecies of fish or wildlife or plants, and any distinct 
population segment of any species of vertebrate fish or wildlife that 
interbreeds when mature. The finding is based upon all information 
provided or referenced in the petition and all other information 
available to us at the time the finding was made. To the maximum extant 
practicable, this finding is to be made within 90 days of receipt of 
the petition, and the finding is to be published promptly in the 
Federal Register. If we find substantial information present, we are 
required to promptly commence a review of the status of the species (50 
CFR 424.14). ``Substantial information'' is defined in 50 CFR 424.14(b) 
as ``that amount of information that would lead a reasonable person to 
believe that the measure proposed in the petition may be warranted.''
    On December 16, 1999, we received a formal petition to list the 
CRCT as threatened or endangered in its occupied habitat within its 
known historic range, in accordance with provisions in section 4 of the 
ESA. The petition was filed by the Center for Biological Diversity, the 
Biodiversity Legal Foundation, Biodiversity Associates, Ancient Forest 
Rescue, Southwest Trout, Wild Utah Forest Campaign, Colorado Wild, and 
Mr. Noah Greenwald.
    On January 12, 2000, we notified the petitioners that our Listing 
Priority Guidance, published in the Federal Register (64 FR 57114) on 
October 22, 1999, designated the processing of new listing petitions as 
a ``Priority 4'' activity, a lower priority than emergency listing 
(Priority 1), processing final decisions on proposed listings (Priority 
2), and resolving the status of candidate species (Priority 3). We also 
informed the petitioners that due to staff and budget limitations, the 
petition could not be immediately addressed.
    On August 8, 2000, we received a notice of intent to sue from the 
Center for Biological Diversity, Biodiversity Associates, Biodiversity 
Legal Foundation, Colorado Wild, Wild Utah Forest Campaign, and Mr. 
Noah Greenwald concerning our failure to produce a 90-day finding on 
the subject petition in accordance with the provisions of section 4 of 
the ESA. We responded on August 31, 2000, reiterating that we would not 
be able to begin an evaluation of the CRCT petition until the work on 
the higher priority activities was completed. In the spring of 2003, 
the Service determined appropriate funds were available to address the 
subject petition.
    In addition, the Service received correspondence from Mr. Noah 
Greenwald on September 20, 2002, providing additional information.
    The September 20, 2002, correspondence from the petitioners 
recognized that some of the information presented in the original 
petition is outdated due to the passage of time. The petitioners 
discussed information provided by the states focusing on three specific 
issues--hybridization, competition, and predation from nonnatives; 
habitat degradation; and inadequacy of existing regulation. The 
petitioners again asserted that the range

[[Page 21152]]

of the CRCT has been reduced to a small fraction of its historic range, 
resulting in small isolated populations. They also stated that none of 
the populations can be considered secure because every one is 
threatened by nonnatives, limited stream length, small population size, 
habitat limitations, or a combination of these factors. The petitioners 
asserted that most CRCT populations are either hybridized or sympatric 
with nonnative trout species despite efforts to construct barriers and 
remove nonnatives. In addition, the States stock nonnative trout in 
CRCT historic range, which limits potential streams where CRCT can be 
recovered. The petitioners recommended that we use the same criteria to 
evaluate the status of the Colorado River cutthroat trout as was used 
for the Rio Grande cutthroat trout (Onchorhynchus clarki virginalis) 
candidate status review. The Service did not use these criteria in this 
90-day finding because it does not constitute a status review under the 

Biology and Distribution

    The CRCT is the only salmonid (i.e., salmon, trout, and their close 
relatives) native to the upper Colorado River basin, and is 1 of 14 
subspecies of cutthroat trout recognized by Behnke (1992, 2002) that 
are native to interior regions of western North America. It has red or 
orange slash marks on both sides of the lower jaws and relatively large 
spots concentrated on the posterior part of the body. Sexually mature 
males exhibit brilliant colors; the ventral region can be bright 
crimson, with red along the lateral line, and the lower sides of the 
body are typically golden yellow (Behnke 1992).
    The CRCT historically occupied portions of the Colorado River 
drainage in Wyoming, Colorado, Utah, Arizona, and New Mexico (Behnke 
1992). Its original distribution probably included portions of larger 
streams, such as the Green, Yampa, White, Colorado, and San Juan 
Rivers. Behnke and Zarn (1976) suggested this subspecies was absent 
from the lower reaches of many large rivers because of summer thermal 
barriers. The CRCT still occurs throughout its historic range, but 
remaining populations now occur mostly in headwater streams and lakes.
    The CRCT spawn over a gravel substrate in spring when water 
temperatures reach 7[deg]C (45[deg]F). The female digs out a nest in 
flowing water and, after fertilization, the eggs are covered with 
gravel and hatch in the summer (Behnke and Benson 1980). The CRCT feed 
on a wide range of invertebrates; larger CRCT prey on other fishes 
(Behnke and Benson 1980).
    The States of Colorado, Utah, and Wyoming have implemented 
conservation efforts for CRCT for many years. Each State has developed 
plans to facilitate conservation action for CRCT within their 
respective States (Wyoming Game and Fish Department (WGFD) 1987; 
Colorado Division of Wildlife (CDOW) 1992; Langlois et al. 1994; Utah 
Division of Wildlife Resources (UDWR) 1997). The three States, U.S. 
Forest Service (USFS), Bureau of Land Management (BLM), National Park 
Service, Ute Indian Tribe, and the Service formed a task force to 
address conservation efforts for CRCT on a rangewide basis. A 
Conservation Agreement and Strategy (CAS) (CRCT Task Force 1999, 2001) 
was developed to expedite implementation of conservation measures for 
the CRCT in Colorado, Utah, and Wyoming as a collaborative and 
cooperative effort among resource agencies. The primary goal of the CAS 
is to assure the long-term prosperity of CRCT throughout their historic 
range by establishing two self-sustaining metapopulations, each 
consisting of five separate, viable but interconnected subpopulations, 
in each geographic management unit within the historic range. The 
short-term goal is to establish one metapopulation in each geographic 
management unit. Additional goals of the CAS are to maintain areas that 
currently support abundant CRCT and manage other areas for increased 
abundance; to maintain the genetic diversity of the subspecies; and to 
increase the distribution of CRCT where ecologically and economically 
feasible. The specific objective of the CAS is to maintain and restore 
383 conservation populations in 2,823 stream kilometers (km) (1,754 
stream miles (mi)) and 18 populations in 264 lake hectares (ha) (652 
lake acres (ac)) in 14 geographic management units within the historic 
    The CAS (CRCT Task Force 2001) classifies CRCT populations 
according to their genetic purity using the criteria established in 
``Cutthroat Trout Management-- a Position Paper. Genetic Considerations 
Associated with Cutthroat Trout Management'' (UDWR 2000). This position 
paper was developed by fishery administrators and biologists from the 
following agencies--Idaho Department of Fish and Game; Montana Fish, 
Wildlife and Parks; Nevada Division of Wildlife; New Mexico Game and 
Fish; UDWR; WGFD; the Service; USFS; and other technical experts. The 
Position Paper defines a ``core conservation population'' as a 
population that is 99 percent pure and represents the 
historic genome of the native cutthroat trout. Core conservation 
populations contain cutthroat trout that have not been impacted by 
genetic alteration linked to human intervention. A ``conservation 
population'' is defined as a reproducing and recruiting population of 
native cutthroat trout that has managed to preserve the historical 
genome and/or unique genetic, ecological, and/or behavioral 
characteristics. In general, a conservation population is at least 90 
percent pure CRCT, but purity may be lower depending on circumstances 
and the values and attributes to be preserved.
    The CAS established a CRCT Coordination Team to periodically update 
the population status information provided in the appendices. As of 
July 16, 2003, the States of Colorado, Utah, and Wyoming reported 327 
conservation populations, which include 286 populations in 
approximately 1,625 stream km (1,010 stream mi) and 41 populations in 
approximately 455 ha (1,124 ac) of lakes (CRCT Coordination Team, 
unpublished data). These populations include 221 populations that meet 
the Coordination Team's definition of core conservation populations. Of 
these 221 core conservation populations, 191 are found in approximately 
1,101 km (684 mi) of streams and 30 are found in approximately 221 ha 
(545 ac) of lakes.
    Since 1998, 125 stream populations and 29 lake populations have 
been added to the list of conservation populations (including core 
conservation populations and conservation populations) (CRCT 
Coordination Team, unpublished data). Most of the additions to the list 
of conservation populations are due to results of genetic testing that 
indicated genetic purity of at least 90 percent. Some waters were 
removed from the list due to the results of genetic testing. Other 
waters were added after reclamation and restocking were completed. 
Still other stream segments were removed because CRCT were extirpated 
due to competition from nonnative trout.

Assessment of the Petition and Other Available Information

    The 1999 petition and subsequent 2002 letter provided information 
regarding the status and threats to CRCT. Soon after we received the 
petition, we made the document available on our web site. We also 
contacted natural resource agencies whose responsibilities include CRCT 
management and requested that these agencies review the petition and 
provide information on the current

[[Page 21153]]

status of the subspecies. In response to our request, we received 
information from UDWR, WGFD, CDOW, USFS, National Park Service, and 
BLM. We reviewed the information provided by these agencies, scientific 
journal articles, agency reports, and other information in our files to 
determine whether the information provided or cited in the petition or 
other information readily available to us met the ESA's standard for 
``substantial information.'' We respond to each of the major assertions 
made in the petition, organized by ESA listing factors. This 90-day 
finding is not a status assessment and does not constitute a status 
review under the ESA.

A. The Present or Threatened Destruction, Modification, or Curtailment 
of Its Habitat or Range

    With respect to factor A, the petition asserted that the CRCT has 
been reduced to small, unstable headwater drainages in less than 5 
percent of its historic range and that this reduction in range is due 
to livestock grazing, water diversions, mining, logging, and roads. The 
petition presented an analysis of the reduction of historic range 
primarily based on information in a USFS Report (Young et al. 1996). 
While we consider this report a source of reliable information, it was 
based on a questionnaire distributed to various agency biologists and 
not all biologists responded. Therefore, Young et al. (1996) considered 
the data base presented as incomplete. The information contained in 
this report gave a general overview of the decline of the subspecies, 
but did not contain adequate information on the subspecies' status 
throughout its current or historical range to determine reduction in 
historic range. In fact, Young et al. (1996) stated, ``comprehensive 
descriptions of the historical range of the CRCT are unavailable.'' 
However, for years, scientists have recognized that the current range 
of the CRCT has been greatly reduced from its historic range (Behnke 
and Zarn 1976; Binns 1977; Behnke and Benson 1980; Martinez 1988; CRCT 
Task Force 2001), and we concur with the conclusion that the range of 
the CRCT has been greatly reduced from historic levels. The ESA does 
not indicate threshold levels of historic range at which listing as 
either threatened or endangered becomes warranted. Instead the 
principal considerations in determining whether a species warrants 
listing are the threats that currently confront the species within its 
range and the likelihood that the species will persist in the 
foreseeable future.
    The petition used two sources of information for the distribution 
and status of CRCT--Young et al. (1996) and the 1999 CAS (CRCT Task 
Force 1999). While the Service considered these adequate and reliable 
sources of information at the time of the original petition, new 
information is also available to the Service, including the latest 
information (CRCT Coordination Team, unpublished data) on numbers of 
conservation populations and core conservation populations by State.
    While the total number of conservation populations (106) and core 
conservation populations (221) represents a relatively secure 
subspecies, total numbers of populations does not provide the full 
picture of the status of a species. The CAS (CRCT Task Force 2001) 
recognized that some past and present land management practices 
(overgrazing, heavy metal pollution, and water depletion and 
diversions) contribute to the isolation of upstream populations of 
CRCT. In some cases those practices serve to protect populations from 
invasion by nonnative salmonids, but they also cause fragmented stream 
segments that restrict movement between formerly connected populations, 
leaving small isolated populations that may be subject to extirpation 
and loss of genetic interchange (CRCT Task Force 2001). Many of these 
populations occur in headwater streams where water temperatures and 
small stream size make habitat conditions less than optimal. Harig and 
Fausch (2002) noted that cold summer water temperatures, typical of 
high elevation streams, tend to delay spawning, which reduces 
overwinter survival. They also found that many small streams lack 
sufficient pools deep enough for overwinter survival. The work of 
Novinger and Rahel (2003) also suggested that isolated headwater 
mountain streams lack some of the necessary habitat components based on 
the finding , in some cases, that isolation management (the process of 
constructing an artificial barrier, removal of brook trout, and 
stocking CRCT) resulted in more CRCT below the artificial barrier than 
above. However, small, isolated populations have persisted for many 
years in some situations, such as above waterfalls or in desert basins 
(Hilderbrand and Kershner 2000). It is unclear what population and 
habitat sizes are required for long-term population viability.
    The scientific literature addresses species population viability in 
a theoretical manner, providing recommendations for minimum population 
size based on theoretical models (Franklin 1980; Gilpin and Soule 1986; 
Rieman and McIntyre 1993; Hilderbrand and Kershner 2000). Through 
modeling, Hilderbrand and Kershner (2000) estimated minimum stream 
length for several subspecies of cutthroat trout (Colorado River, 
Bonneville (Oncorhynchus clarki utah), and westslope (Oncorhynchus 
clarki lewisi)), in relation to population size. They estimated that a 
stream length of 3 km (2 mi) was required to support a population of 
1,000 fish; 8 km (5 mi) to support 2,500 fish; and 17 km (10 mi) to 
support 5,000 fish. Recent data show stream lengths for core 
conservation populations vary from less than 1.5 km to 34 km (less than 
1 mi to 21 mi), with 77 of the 191 (40 percent) core conservation 
populations in stream segments of 3 km (2 mi) or less (CRCT 
Coordination Team, unpublished data). Core conservation populations of 
CRCT ranged in size from 20 to 6,830 adult fish, with the majority (92 
percent) of the adult populations having either fewer than 1,000 fish 
or no available population data. However, it is important to recognize 
that the Coordination Team has not adopted the population criteria 
discussed above and has not developed specific standards for population 
viability for CRCT (CRCT Task Force 2001). The Coordination Team 
considered using the criteria for demographic and habitat requirements 
for bull trout (Salvelinus confluentus) as presented by Rieman and 
McIntyre (1993), but determined those criteria were not appropriate for 
CRCT. While limited habitat size, small population size, inappropriate 
water temperatures, and habitat fragmentation are a concern, its 
unclear how these factors affect the long-term viability of the 
    When addressing a species with multiple populations, such as CRCT, 
population viability is just one factor to consider when determining 
the likelihood of species persistence. The CAS stresses the 
establishment of metapopulations to assure the long-term prosperity of 
CRCT (CRCT Task Force 2001). The CAS defines metapopulations as ``a 
collection of localized populations that are geographically distinct 
yet are genetically interconnected through natural movement of 
individual fish between populations.'' Metapopulations are important 
for stabilizing population dynamics by maintaining genetic exchange 
(increasing genetic diversity) and providing individuals to repopulate 
stream segments where populations are lost due to stochastic 
environmental events (i.e., fire, drought) (UDWR 1997). The long-term 
goal of the CAS is to

[[Page 21154]]

establish two self-sustaining metapopulations, each consisting of five 
separate, viable but interconnected subpopulations, in each geographic 
management unit within the historic range. Two of the 14 geographic 
management units currently meet the long-term goal of the CAS. The 
short-term goal is to establish one metapopulation in each geographic 
management unit. Seven additional geographic management units currently 
meet the CAS short-term goal. Overall, metapopulations currently exist 
in Colorado, Utah, and Wyoming, where 11 metapopulations meet the 
criteria of 5 separate but interconnected subpopulations and an 
additional 23 metapopulations contain 2 to 4 subpopulations (CRCT Core 
Coordination Team, unpublished data).
    The States are actively working to establish metapopulations in 
each geographic management unit. For example, in Wyoming, a large 
restoration project is currently ongoing to establish a metapopulation 
in the LaBarge watershed in the southwestern portion of the State. 
Completion of this project is expected 2007, and will result in 
restoration of 58 stream miles, including 18 miles of LaBarge Creek and 
40 stream miles of tributaries (Remmick 2002). Challenges in 
establishing metapopulations include difficulty in obtaining approval 
for chemical treatments, reinvasion of nonnative trout, funding, and 
landowner approval. Based on their work in Colorado, Brauch and Hebein 
(2003) found that current technical limitations of chemical treatments 
for reclamation limit potential reclamation sites to smaller streams 
with low flows of less than 0.42 cubic meter/second (15 cubic feet/
second). State efforts to overcome these challenges continue.
    The Service recognizes that overgrazing can be detrimental to trout 
habitat, and that overgrazing may occur in some habitats occupied by 
CRCT. The petition asserted that habitat conditions are degraded in a 
significant portion of the subspecies' range. Descriptions of habitat 
conditions are not available for the CRCT on a rangewide basis (Bruce 
May, USFS, pers. comm. 2003). The petition used the habitat limitations 
data field presented in Appendix A of the CAS to draw this conclusion. 
However, this data field is not adequate to determine the habitat 
condition of individual streams or lakes or to determine the condition 
of the habitat rangewide (Dan Brauch, CDOW, pers. comm. 2003). This 
data field was not applied consistently in the three States, nor was it 
applied consistently over time. In many cases, habitat limitations 
noted for the survey location did not apply to the entire stream reach. 
The CAS (CRCT Task Force 2001) stated that ``habitat problems are 
viewed as site-specific and not an overall threat throughout the 
range,'' but no documentation was provided. The petition did not 
provide additional substantial information to determine the extent of 
overgrazing in CRCT habitat. Furthermore, the Service can not assume 
that all livestock grazing within the CRCT habitat is inappropriate. 
Proper grazing management can reduce or prevent the habitat and water 
quality degradation discussed in the petition.
    The Service recognizes that water diversions can negatively impact 
CRCT habitat. The petition asserted 59 CRCT populations have been 
negatively impacted by water diversions. However, the petition relied 
primarily upon the habitat limitations data field presented in Appendix 
A discussed above. A rangewide inventory has not been conducted to 
determine if water diversions are a problem in just a few locations or 
throughout CRCT range. Many CRCT populations occur in stream segments 
upstream of water diversions, and some instream flows have been secured 
in CRCT streams in Colorado and Wyoming. In Utah, the State Engineer 
has the authority to deny any changes in water rights applications if 
such action ``affects the natural stream environment or public 
    Additionally, the petition asserted mining, dams and reservoirs, 
oil and gas development, road building and logging may be detrimental 
to CRCT populations. The petition also asserted that mining, through 
isolation, and dams and reservoirs have preserved pure populations of 
CRCT. Information on the impacts of dams and reservoirs, oil and gas 
development, road building and logging is not available on a rangewide 
basis. The petition did not provide substantial information to 
determine the rangewide impact on CRCT habitat. We have no other 
information establishing these activities as significant threats to 
    The USFS and the BLM are currently implementing conservation 
actions on Federal lands to improve habitat conditions for CRCT (USFS 
2002, BLM 2003). These actions include grazing management by 
constructing fencing, building exclosures, and resting grazing 
allotments. Other vegetation management activities to improve riparian 
conditions include weed control and riparian plantings. The BLM has 
recently facilitated installation of a fish screen to prevent CRCT from 
entering a water diversion structure and implemented culvert 
improvements to provide fish passage. The USFS has moved campsites and 
excluded vehicle access to improve habitat for CRCT. The Federal 
agencies have partnered with the State agencies to monitor fish 
populations, build and maintain barriers, and remove nonnative fish. 
Some CRCT habitats are afforded protection from land use activities by 
special land use designations, such as habitats within Rocky Mountain 
National Park and USFS Wilderness Areas.
    We find the petition did not provide substantial information to 
support its assertions that the threat of past and present destruction, 
modification, or curtailment of CRCT habitat is sufficient to cause 
further significant declines in this subspecies' range or extant 
populations. We conclude that the total number of conservation 
populations and core conservation populations represent a relatively 
secure subspecies. While limited habitat size, small population size, 
inappropriate water temperatures, and habitat fragmentation are a 
concern, it is unclear how these factors affect the long-term viability 
of the subspecies. State management efforts to establish 
metapopulations in each geographic management unit continue to improve 
the outlook for the CRCT. Further, the petition failed to provide 
substantial information to support the allegation that overgrazing, 
mining, logging, or roads pose a threat to the overall habitat or range 
of the CRCT.

B. Overutilization for Commercial, Recreational, Scientific, or 
Educational Purposes

    With respect to factor B, the petition asserted that CRCT are 
threatened by recreational fishing, because CRCT are easy to catch and 
the state regulatory agencies lack sufficient funding to enforce 
protective regulations effectively. Colorado, Utah, and Wyoming all 
have special regulations that provide protection against overharvest of 
CRCT. These special regulations include catch-and-release requirements, 
very limited harvest, fishing closures, and tackle restrictions. Also, 
the remote locations of many CRCT streams provide protection from heavy 
fishing pressure (CRCT Task Force 2001).
    The CDOW placed harvest and tackle restrictions on most 
conservation populations of CRCT in 1999. These regulations prohibit 
harvest of CRCT and allow anglers to only use flies and lures (i.e., no 
bait). The CDOW reports that 49 waters with conservation populations 
are closed to cutthroat trout harvest and 1 lake is closed to fishing 
(Brauch and Hebein 2003). In Rocky

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Mountain National Park, all waters that contain pure native cutthroat 
trout are limited to catch-and-release angling (except Caddis Lake and 
Lake Nanita, where there is a two-fish daily limit), and some waters 
are closed to angling while restoration efforts are being implemented 
(Rosenlund et al. 2001).
    In the early 1980s, the WGFD implemented regulations to better 
manage CRCT waters. Some waters have complete fishing closures; other 
waters are catch-and-release only, reduced limits, and seasonal 
closures. The WGFD continually revises fishing regulations to protect 
species of concern (Remmick 2002). The WGFD assigned a warden to 
enforce fishing closures near CRCT habitat when roads were constructed 
in association with the Cheyenne Stage II Water Project in the Little 
Snake River drainage in Wyoming (Remmick 2002).
    In Utah, the UDWR has established seasonal closures, reduced 
limits, size restrictions, and implemented fishing closures in areas of 
recent introductions to protect CRCT. The UDWR has not observed small, 
remote populations getting enough fishing pressure to influence numbers 
and size structure (Kimball 2001).
    While the petition recognizes that existing fishing regulations are 
in most cases adequate, it raises concerns that funding for education 
and enforcement programs may be inadequate. However, the petition and 
information available in the Service's files fails to provide 
documentation to support this assertion.
    Based on the existing regulations described above, we conclude that 
the scientific and commercial information available does not support 
the assertion that overutilization by recreational angling is a threat 
to CRCT. Furthermore, the petition failed to present substantial 
information regarding a lack of sufficient funding for education and 
enforcement of the regulations.

C. Disease or Predation

    With respect to factor C, the petition asserted that CRCT are 
threatened by whirling disease and the CDOW stocks whirling disease-
infected fish within the historic range of CRCT. Also, the petition 
asserted that CRCT are threatened by predation from brown, brook, and 
rainbow trout. In recent years, whirling disease has become a great 
concern to fishery managers in western States. Whirling disease is 
caused by the nonnative myxosporean parasite, Myxobolus cerebralis. 
This parasite was introduced to the United States from Europe in the 
1950s and requires two separate host organisms to complete its life 
cycle. Its essential hosts are a salmonid fish and an aquatic worm, 
Tubifex tubifex. Field experiments have shown that CRCT are very 
susceptible to whirling disease, with an 85 percent mortality rate over 
a 4-month period when CRCT were exposed to the parasites in the 
Colorado River (Thompson et al. 1999). However, Tubifex tubifex is 
usually most abundant in areas of high sedimentation, low water 
temperatures, and low dissolved oxygen. Most populations of CRCT occur 
in cold water stream habitats at high elevations, where Tubifex tubifex 
is unlikely to be abundant. Thompson et al. (1999) found infection 
rates to be low when temperatures are less than 10[deg]C (50[deg]F). 
Out of the hundreds of CRCT populations reported by the States, only a 
few populations of CRCT in Utah and Wyoming have been infected by 
whirling disease (Kimball 2001, Remmick 2002). In Colorado, CDOW has 
not found any native cutthroat population infected with whirling 
disease (Nesler 2003). Wyoming reports that no core conservation 
populations or conservation populations have been infected (Remmick 
2002). All three States have developed management activities to protect 
CRCT populations from whirling disease.
    In Colorado, policies require that only fish that have tested 
negative for Myxobolus cerebralis, within the last 60 days are 
permitted to be released into CRCT waters. Colorado also requires 
disease-free certification and requires the use of isolation/quarantine 
units for CRCT stocks (CRCT Task Force 2001). Utah has some of the most 
stringent fish disease laws in the United States. Utah has a Fish 
Health Board that oversees the disease testing protocol. Utah does not 
allow stocking of fish that test positive for whirling disease anywhere 
(CRCT Task Force 2001). A couple of CRCT waters in Utah have been 
infected by whirling disease, and the UDWR is studying the effects of 
whirling disease on these populations (Kimball 2001). Wyoming has a 
policy that any fish testing positive for Myxobolus cerebralis will not 
be stocked (Remmick 2002).
    We find that the scientific and commercial information available 
supports the allegation that CRCT are susceptible to whirling disease, 
but due to the physical characteristics of CRCT habitat and the current 
State policies, whirling disease does not pose a significant threat to 
    Predation was recognized in the petition in association with the 
presence of nonnative trout in CRCT habitat. The CRCT are often 
replaced by nonnative trout, primarily brook trout (Salvelinus 
fontinalis), where they occur in the same habitat; but the degree to 
which predation is a factor in this replacement has not been well 
studied (Peterson and Fausch 2002). We find that there is insufficient 
information to conclude that predation by nonnative fishes is a 
significant threat to CRCT.

D. The Inadequacy of Existing Regulatory Mechanisms

    With respect to factor D, the petition asserted that currently 
there are no regulations protecting the species from take or habitat 
degradation. The petition and subsequent correspondence failed to 
recognize all of the ongoing efforts of the signatories of the 2001 
Conservation Agreement. The States of Utah, Wyoming, and Colorado, and 
the Federal land management agencies all have ongoing programs to 
conserve the CRCT.

Colorado Division of Wildlife

    The CDOW includes the CRCT on a list of species of special concern. 
Colorado fishing regulations provide restrictive regulations for some 
CRCT waters. These restrictions include angling limited to artificial 
flies and lures and immediate return of all trout alive to the water. A 
recent report outlines conservation activities conducted by the CDOW 
during 1999-2002 (Brauch and Hebein 2003). The CDOW reported that, 
during this period, 311 streams and lakes were targeted for 
conservation activities. Statewide conservation activities included 
restrictive tackle and catch-and-release regulations, regulations 
prohibiting nonnative stocking into conservation populations, and 
stocking CRCT for recreation into high lakes. Other conservation 
activities included development of subbasin brood stocks, removal of 
nonnative trout, protection of populations with barrier construction, 
genetic testing, and population monitoring. The Colorado Water Quality 
Control Division and Commission regulate water quality and set water 
quality standards to protect aquatic life in coldwater environments.

Utah Division of Wildlife Resources

    Utah lists CRCT as a conservation species, which is defined as 
currently receiving sufficient special management under a conservation 
agreement to preclude listing as endangered, threatened, or species of 
special concern in Utah. Utah's stocking practices have changed in 
recent years to protect CRCT. Stocking of nonnative fishes no longer 
occurs near core conservation populations or conservation populations. 
In 2002, Utah discontinued

[[Page 21156]]

stocking rainbow trout in most streams and now only stocks sterile 
rainbow trout. Sterile rainbow trout are stocked only in areas that 
have no connection to CRCT habitat. All stocking of nonnative 
cutthroats was discontinued by 2000. Utah fishing regulations restrict 
harvest of CRCT and implement fishing closures during restoration 

Wyoming Game and Fish Department

    Wyoming protects CRCT through fishing regulations and stocking 
procedures. Restrictions on angling include reduced bag limits, catch-
and-release fishing, seasonal closures, and complete closures. The WGFD 
has filed for water rights on a total of 30 stream segments of CRCT 
habitat, for a total of 187 km (116 mi). Priority dates for these 
filings range from 1989 to 2002. To date, two instream flow rights have 
been approved. The Wyoming State Division of Environmental Quality 
implements water quality regulations and controls that apply to CRCT 

U.S. Forest Service

    The USFS has designated CRCT as a sensitive species. According to 
the USFS, the petition misrepresented their aquatic habitat management 
program and land-use coordination by taking statements in reports out 
of context (USFS 2003). The U.S. Department of Agriculture policy 
directs the USFS to manage ``habitat for all existing native and 
desired nonnative * * * species in order to maintain at least viable 
populations of such species and to avoid actions that may cause a 
species to become threatened or endangered.'' While specific population 
viability criteria have not been established by the CRCT Coordination 
Team, this policy requires the USFS to make a judgment on the viability 
of each individual population where authorized activities may impact 
    The 2001 CAS was used as a basis for recovery and conservation 
strategies for Standards and Guidelines within individual Forest Plans, 
in combination with the Fisheries and Aquatic Ecology section of the 
Forest Planning Desk Guide. For example, the standards for the White 
River National Forest Plan in Colorado include provisions to: maintain 
or enhance existing CRCT habitat; reduce sediment from existing roads 
and trials; maintain pool depths; maintain riparian vegetation; and 
retain large woody debris in streams. Guidelines to implement these 
standards include restriction on new roads, rerouting existing roads, 
decommissioning old roads, altering timing of grazing, excluding 
sensitive or problem areas from grazing, and controlling livestock 
crossings. In the past 5 years, the USFS has completed 200 biological 
evaluations that address CRCT.
    The USFS (2002) reported that the Rocky Mountain Region in 2002 
implemented 51 conservation actions that positively influenced 64 lake 
ha (158 lake ac) and 727 stream km (452 stream mi) of CRCT habitat. 
Projects included inventory of existing and potential habitat, drought 
salvage, fencing to exclude cattle, stream assessment and monitoring, 
nonnative trout removal, building and maintaining barriers, moving 
dispersed campsites, and genetic analysis. Over the last 4 years the 
USFS has provided $2,097,100 for the implementation of 112 conservation 

Bureau of Land Management

    The CRCT is on the BLM's Sensitive Species List. The BLM prepares 
Work Plans and Accomplishment Reports for conservation efforts on BLM 
lands in Colorado, Utah, and Wyoming. Conservation actions are either 
planned or have been implemented on approximately 40 CRCT streams.

National Park Service

    The current fisheries management objectives in Rocky Mountain 
National Park were established in 1969, when the stocking of nonnative 
and hybrid fishes was no longer permitted. Lakes that did not maintain 
reproducing populations of fish became fishless (Rosenlund et al. 
2001). Five sites that contain core conservation populations within 
Rocky Mountain National Park are open to catch-and-release fishing, and 
four other sites have a two-fish limit. Most CRCT waters within the 
Park are in high-elevation remote locations, where angling pressure is 
very light. Livestock grazing, timber harvest, mining, or other 
development does not occur in Rocky Mountain National Park.
    The scientific and commercial information available does not 
support the petition's assertion that there are no regulations 
protecting the species from take or habitat degradation. We conclude 
that take of the subspecies can be controlled by State regulations and 
that the Federal land management agencies have policies to manage 
sensitive species habitat.

E. Other Natural or Manmade Mechanisms

    With respect to factor E, the petition asserted that a major threat 
to CRCT is competition and hybridization from nonnative trout species 
occurring in the same habitat as CRCT. It also asserted that small 
isolated populations of CRCT are vulnerable to stochastic events, such 
as fire or drought. Hybridization with nonnative fish species has been 
recognized as one of the most significant threats to CRCT (Behnke 1992; 
Young et al. 1996; CRCT Task Force 2001). Hybridization occurs when 
nonnative species interbreed with CRCT, and the offspring survive. The 
nonnative species that hybridize with CRCT are primarily rainbow trout 
and other subspecies of cutthroat trout. If the hybrids survive and 
interbreed with one or both of the parental species, it is called 
introgressive hybridization. This can lead to loss of genetic purity in 
the population and result in a population that consists entirely of 
individuals that contain genetic material from both species (i.e., a 
hybrid swarm). Nonnative salmonids have been stocked in CRCT habitat 
since the late 1800s throughout CRCT historic range. The State agencies 
have spent considerable time and money in recent years testing 
populations to determine their genetic purity.
    Determining genetic purity is a complex issue and a single standard 
has not been established. Methods used by the States to determine 
genetic purity have changed over the years. Analysis by meristics 
(counts of body parts) was used for many years, but now various 
molecular genetic techniques (i.e., mitochondrial deoxyribonucleic acid 
(DNA), nuclear DNA, allozymes) are available and can detect very small 
amounts of introgression. Many of the core conservation populations 
have been confirmed to be pure (<1 percent introgression) with these 
molecular genetic techniques. Many other test results are pending. In 
general, scientists have found that genetic testing confirms the 
results of the earlier meristic techniques (Brauch and Hebein 2003; 
Hepworth et al. in press). All three States continue the process of 
genetic testing, using the latest techniques. An evaluation of known 
stocking history and genetic and meristic information is considered in 
determining core conservation populations.
    Current policies preclude stocking of nonnative trout in CRCT 
habitat, and recent genetics work has added significantly to the number 
of core conservation populations (99 percent pure). As of 
July 2003, 221 core conservation populations are known to exist in 
Colorado, Utah, and Wyoming. There are varying amounts of information 
available regarding the genetic purity of these core conservation 
populations. Since 1999, Wyoming has added 20 core conservation 
populations and Colorado has added 25 core

[[Page 21157]]

conservation populations as the result of genetic testing. Some 
populations are added to the list of core conservation populations, and 
others are dropped from the list as genetic testing continues. Far more 
populations have been added to the list of core conservation 
populations through genetic testing than have been removed (Brauch and 
Hebein 2003; Conway 2003; Stone 2003). In addition to the core 
conservation populations, there are 106 conservation populations that 
are classified as 90 to 99 percent pure.
    Hybridization continues to be a threat where nonnative species, 
particularly rainbow trout (Oncorhynchus mykiss) and nonnative 
cutthroat trout, occur in the same habitat as CRCT. The most recent 
data show that only 8 of the 221 core conservation populations coexist 
with rainbow trout or another subspecies of nonnative cutthroat trout 
(although information on presence of nonnative salmonids is not 
available for 22 of the populations). Because core conservation 
populations are defined as 99 percent pure, one would expect 
a very low occurrence of other species or subspecies that are known to 
interbreed with CRCT in the core conservation population waters.
    Competition from nonnative trout, especially brook trout, also has 
been recognized as a major threat to CRCT (Behnke 1992). Studies have 
shown CRCT are displaced when brook trout occur in the same habitat. A 
recent study conducted by Colorado State University found survival of 
young CRCT was greatly impacted by the presence of brook trout, while 
adult CRCT survival was not impacted (Peterson and Fausch 2002). Since 
2001, four conservation populations in Colorado (Corral Creek, Cub 
Creek, Express Creek, and Nolan Creek) have been completely displaced 
by brook trout (Brauch and Hebein 2003).
    Brook trout are no longer stocked in CRCT waters in Colorado, Utah, 
or Wyoming. Recent data (CRCT Coordination Team, unpublished data) show 
that brook trout are absent from 139 of the 199 core conservation 
populations that have been surveyed for nonnative salmonids. 
Recognizing the threat posed by brook trout, the responsible agencies 
are actively implementing management techniques, such as the 
construction of barriers, the removal of brook trout, and the 
curtailment of stocking brook trout within CRCT waters. Between 1999 
and 2002, Colorado, Utah, and Wyoming completed chemical treatments in 
36 CRCT waters, for a total of 88 stream miles and 87 lake acres in 8 
geographic management units (CRCT Coordination Team, unpublished data). 
Colorado also removed brook trout by electrofishing in 20 waters.
    Fish barriers have been constructed on CRCT streams to prevent the 
upstream movement of nonnative salmonids. The CAS identifies the 
construction of barriers as a strategy to protect and restore existing 
habitat. It also recognizes that natural barriers can be effective. 
Recent data show 117 (53 percent) of the existing core conservation 
populations are currently protected by a natural or artificial barrier 
(CRCT Coordination Team, unpublished data). However, the Service 
recognizes that barriers are not a guarantee that non-natives will not 
be present in CRCT habitat. Thirty-two percent of the core conservation 
populations with barriers have nonnative salmonids present.
    Ultimately, a larger watershed approach may be necessary for the 
long-term persistence of CRCT populations (Hilderbrand and Kershner 
    The Service recognizes that stochastic events can be detrimental to 
individual populations of CRCT. The primary goal of the CAS is to 
establish metapopulations within each geographic management unit to 
assure the long-term prosperity of CRCT. While all the specific 
metapopulation goals of the CAS have not been met, metapopulations 
connecting 2 or more streams do occur in 14 out of the 15 geographic 
management units (Table 3). The Service agrees with the assertion in 
the petition that once an isolated population is lost, there are no 
natural means for these populations to recruit new members. However, 
management actions have been taken by the States to repopulate CRCT 
streams after stochastic events. For example, during the 2002 drought, 
Colorado salvaged fish from Trapper Creek and West Antelope Creek and 
held the fish in refugia for return to the wild when conditions 
improved and for the establishment of broodstock for supplying fish for 
stocking into the respective hydrologic subbasins (Brauch and Hebein 
    Although some CRCT populations are threatened by hybridization, we 
conclude that the threat of hybridization is not pervasive to the 
extent that it poses a risk to the continued survival of CRCT. The 
Service recognizes that nonnatives can outcompete CRCT. However, brook 
trout are absent from 139 of the 199 core conservation populations that 
have been surveyed for nonnative salmonids. Management techniques such 
as the construction of barriers, the removal of brook trout and the 
curtailment of stocking brook trout within CRCT waters are currently 
being implemented by responsible agencies. Therefore, we conclude that 
the petition and other documents in our files do not provide evidence 
that competition with brook trout presents a significant threat to the 
subspecies within the foreseeable future. While stochastic events will 
always pose a threat to individual populations, the establishment of 
metapopulations and state management actions should minimize this 


    We conclude that the petition and other documents in our files do 
not present substantial information to lead a reasonable person to 
believe that listing the CRCT as threatened or endangered may be 
warranted. After reviewing recent data, we conclude that there are a 
significant number of core conservation populations of CRCT distributed 
throughout historic range and that agencies are implementing management 
actions to improve the status of these populations. Since 1998, 125 
stream populations and 29 lake populations have been added to the list 
of conservation populations for a total of 286 stream populations and 
41 lake populations. This increase in population numbers can be 
attributable to results of genetic testing, removal of nonnatives, and 
stocking. The total number of conservation populations and core 
conservation populations represents a relatively secure subspecies. The 
States and the Federal agencies report that there are currently 11 
metapopulations with 5 or more interconnected subpopulations and 23 
metapopulations with 2 to 4 interconnected subpopulations. Work is 
ongoing to establish additional metapopulations throughout the CRCT's 
historic range. The Federal land management agencies are currently 
implementing conservation actions in CRCT habitat such as grazing 
management, recreation management, weed control, and riparian 
plantings. The State and Federal agencies work cooperatively to 
construct and maintain barriers, remove nonnative fish, and monitor 
fish populations.
    The petition asserted that overgrazing, water diversions, mining, 
dams and reservoirs, oil and gas development, road-building and logging 
are detrimental to CRCT. The Service finds the information in the 
petition was not adequate to assess the impacts rangewide. While 
limited habitat size, small population size, inappropriate water 
temperatures, and habitat fragmentation are a concern, it is unclear 
how these factors affect the long-term viability of the subspecies.

[[Page 21158]]

We do not agree with the petitioners' conclusion that none of the 
populations can be considered secure because every one is threatened by 
nonnative fishes, limited stream length, habitat limitations, or a 
combination of these factors.
    Historically, overharvest of CRCT may have significantly reduced 
the numbers of CRCT in some areas, but we find that fishing regulations 
enacted by the States and the National Park Service provide measures 
that preclude excessive take by recreational angling. The petition did 
not present substantial information indicating funding to enforce or 
educate the public about these regulations was inadequate. Also, many 
CRCT waters are located in remote locations that experience very light 
fishing pressure.
    Whirling disease is a significant concern for trout in general, but 
very few CRCT populations have tested positive for the disease and all 
three States are implementing management actions to protect CRCT from 
whirling disease. Also, much of the habitat for CRCT is unlikely to be 
conducive to the whirling disease pathogen. Therefore, we do not agree 
with the petition's assertions that overutilization or whirling disease 
present significant threats to CRCT. With regard to predation by 
nonnative fishes, we find that there is insufficient information to 
conclude that this issue is a significant threat to CRCT.
    The Federal land management agencies all have programs in place to 
regulate land management activities. The petition did not provide 
evidence to support its allegation that these programs are not 
providing adequate protection, and why they are not effective in 
conserving CRCT. Service files do not contain adequate information on 
habitat conditions to make an informed determination as to whether 
Federal lands are being adequately protected or enhanced by existing 
regulations and policies. Thus, the Service has no reason to assume the 
programs in place for CRCT management are inadequate.
    Although some CRCT populations are threatened by hybridization, we 
conclude that significant numbers of populations have been determined 
to be core conservation populations (99 percent pure). 
Further, the States have implemented policies to protect the genetic 
purity of the core conservation populations. Competition from brook 
trout is recognized as a threat to CRCT and the State and Federal 
agencies are implementing management techniques to offset this threat. 
Many core conservation populations (53%) are protected by natural or 
artificial barriers and the States have ongoing programs to remove 
brook trout from CRCT waters.
    The petition failed to recognize the ongoing conservation efforts 
of the members of the CRCT Coordination Team. Numerous conservation 
efforts are ongoing in all three States and in general appear to be 
well funded. We conclude that the management programs currently in 
place for CRCT are improving the status of this subspecies and 
continued improvement is anticipated in the future. Therefore, as 
required by section 4(b)(3)(A) of the ESA, we conclude that the 
petition did not present substantial information to demonstrate that 
the listing may be warranted. This finding is based on all information 
available to us at this time.
    References Cited: A complete list of all references cited herein is 
available upon request from the Grand Junction, Colorado Field Office 
    Author: The primary author of this document is Patty Schrader 
Gelatt, Colorado Field Office, Grand Junction, Colorado.

    Authority: The authority for this action is the Endangered 
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

    Dated: April 8, 2004.
Elizabeth H. Stevens,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 04-8633 Filed 4-19-04; 8:45 am]