Endangered and Threatened Wildlife and Plants; 12-Month Finding for a Petition To List the Colorado River Cutthroat Trout as Threatened or Endangered, 32589-32605 [07-2915]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 72, Number 113 (Wednesday, June 13, 2007)]
[Proposed Rules]
[Pages 32589-32605]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 07-2915]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
for a Petition To List the Colorado River Cutthroat Trout as Threatened 
or Endangered

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of a 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce our 
12-month finding for a petition to list the Colorado River cutthroat 
trout (CRCT) (Oncorhynchus clarkii pleuriticus) as a threatened species 
throughout its range in the United States, pursuant to the Endangered 
Species Act of 1973, as amended. After a thorough review of all 
available scientific and commercial information, we find that listing 
the CRCT as either threatened or endangered is not warranted at this 
time. We ask the public to continue to submit to us any new information 
that becomes available

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concerning the status of or threats to the subspecies. This information 
will help us to monitor and encourage the ongoing conservation of this 
subspecies.

DATES: The finding in this document was made on June 5, 2007.

ADDRESSES: Data, information, comments, or questions regarding this 
notice should be sent to CRCT, U.S. Fish and Wildlife Service, 764 
Horizon Drive, Building B, Grand Junction, Colorado 81506. Once the 
complete administrative file for this finding is compiled, it will be 
available for inspection, by appointment, and during normal business 
hours, at the above address. The petition finding, related Federal 
Register notices, the Court Order, and other pertinent information, may 
be obtained on line at https://mountain-prairie.fws.gov/endspp/fish/
CRCT/.

FOR FURTHER INFORMATION CONTACT: Patty Schrader Gelatt, Western 
Colorado Ecological Services Office (see ADDRESSES), by telephone at 
(970) 243-2778, by facsimile at (970) 245-6933, or by electronic mail 
at patty_schradergelatt@fws.gov.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition 
to revise the List of Endangered and Threatened Species that contains 
substantial scientific and commercial information that listing may be 
warranted, we make a finding within 12 months of the date of receipt of 
the petition on whether the petitioned action is (a) not warranted, (b) 
warranted, or (c) warranted but the immediate proposal of a regulation 
implementing the petitioned action is precluded by other pending 
proposals to determine whether any species is threatened or endangered, 
and expeditious progress is being made to add or remove qualified 
species from the List of Endangered and Threatened Species. Section 
4(b)(3)(C) of the Act requires that a petition for which the requested 
action is found to be warranted but precluded be treated as though 
resubmitted on the date of such finding, i.e., requiring a subsequent 
finding to be made within 12 months. Such 12-month findings must be 
published in the Federal Register.
    On December 16, 1999, we received a formal petition (dated December 
9, 1999) 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 Act. The petition was filed by the Center for 
Biological Diversity (CBD), the Biodiversity Legal Foundation, 
Biodiversity Associates, Ancient Forest Rescue, Southwest Trout, Wild 
Utah Forest Campaign, Colorado Wild, and Mr. Noah Greenwald.

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, pp. 139-145; 
2002, pp. 143-147) 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, pp. 
139-145).
    The CRCT historically occupied portions of the Colorado River 
drainage in Wyoming, Colorado, Utah, New Mexico, and likely in extreme 
northeastern Arizona (Behnke 1992, pp. 139-145). Its original 
distribution probably included portions of larger streams, such as the 
Green, Yampa, White, Colorado, and San Juan Rivers. Behnke and Zarn 
(1976, p. 15) 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 Conservation Team is composed of biologists from Wyoming 
Game and Fish Department (WGFD), Utah Division of Wildlife Resources 
(UDWR), Colorado Division of Wildlife (CDOW), U.S. Bureau of Land 
Management (BLM), U.S. Forest Service (USFS), and the Service. The CRCT 
Conservation Team recently completed a rangewide status report (Hirsch 
et al. 2006) that describes the current rangewide status of CRCT in the 
United States. The report summarized information provided by 48 
fisheries professionals from Colorado, Utah, Wyoming, and New Mexico, 
including State wildlife agencies, USFS, BLM, and the Service (Hirsch 
et al. 2006, p. 1). Specific protocols were developed and the 
information was assembled in a Geographic Information System (GIS) 
database. A peer review was conducted on the report by five recognized 
experts in the field of fishery biology, conservation biology, and/or 
genetics. The results of the peer review found that the document 
provided sound scientific data to use as the basis of our 12-month 
finding.
    An analysis of probable historic distribution was provided in this 
status report (Hirsh et al. 2006, pp. 9-10). Historic distribution was 
based on habitat thought to be occupied around 1800 AD. The 
determination of occupation in this time period was based on elevation, 
slope aspect, barriers that would preclude fish, and expertise of 
fishery biologists familiar with each watershed. The analysis 
identified 34,417 kilometers (km) (21,386 miles [mi]) of stream habitat 
as having the potential to have been historically occupied. The 
historically occupied habitat was identified in each State as follows: 
Colorado--21,911 km/13,615 mi (63.6 percent); Utah--5,576 km/3,465 mi 
(16.2 percent); Wyoming--6,735 km/4,185 mi (19.6 percent); New Mexico--
195 km/121 mi (0.6 percent). Scientists contacted regarding historical 
occurrence of CRCT in Arizona believe the drainages in the upper 
Colorado River basin in Arizona did not historically support CRCT 
(Hirsch et al. 2006, p. 2). Some hydrologic units were excluded from 
historic range, because the habitat was thought to be unsuitable due to 
extreme conditions or the habitats were thought to be devoid of fish.
    Current distribution of CRCT is approximately 14 percent of 
probable historically occupied stream miles (Hirsch et al. 2006, p. 
12). Approximately 1 percent (360 km (224 mi)) of currently occupied 
habitat is outside of areas determined to be historic habitat by Hirsh 
et al. (2006, p. 12). These populations are thought to be outside of 
the historic range because they are above historic barriers (natural 
waterfalls) where it is believed fish did not occur historically. These 
populations have been established by stocking CRCT above historic 
barriers.
    The CRCT currently occupy 4,863 km (3,022 mi) of habitat; 2,187 km 
(1,359 mi) in Colorado, 1,788 km (1,111 mi) in Utah, and 888 km (552 
mi) in Wyoming (Hirsch et al. 2006, p. 12). The CRCT are well 
distributed throughout their range in eight watershed-based Geographic 
Management Units (GMUs) (Figure 1). It should be noted that in earlier 
assessments 14 GMUs were identified as including current populations of 
CRCT; however, elimination of State boundaries in the most recent 
assessment reduced the number of GMUs, providing a more watershed-based 
approach. Reducing the number of GMUs does not indicate a reduction in 
the geographic area where CRCT occur (CRCT Conservation Team 2006a, pp. 
7-8). Within each GMU, streams are

[[Page 32591]]

identified to the 4th level hydrologic unit and assigned a hydrologic 
unit code (HUC). The CRCT occupies some habitat in 42 of the 51 HUCs. 
The CRCT is not known to occur in New Mexico and is absent from nine 
HUCs within its historic range: Upper Colorado--Kane Springs, Upper 
Green--Slate, Big Sandy, Vermillion, Middle San Juan, Chaco, Mancos, 
Lower San Juan--Four Corners, and Montezuma.
    Table 1 shows kilometers of currently occupied habitat in each GMU. 
The Upper Green River GMU and the Lower Green River GMU have the 
greatest extent of kilometers of currently occupied habitat for CRCT. 
The Upper Colorado River GMU and the Yampa River GMU also contain a 
substantial portion of occupied habitat. Some GMUs may not have as much 
habitat because they are smaller river drainages, such as the Dolores 
River, and others may be mostly lower elevation with less trout 
habitat, such as the Lower Colorado River GMU.
    The CRCT rangewide status report (Hirsh et al. 2006, p. 29) 
identified 285 stream populations as conservation populations (Figure 
2). Of the 285 conservation populations, 153 are considered core 
populations, meaning that they contain genetically pure Colorado River 
cutthroat trout. A conservation population is defined, per the States' 
position paper on Genetic Considerations Associated with Cutthroat 
Trout Management (UDWR 2000, pp. 1-9), as one that is either 
genetically unaltered (i.e., a core population) or one that may be 
slightly introgressed due to past hybridization (typically less than 10 
percent) yet has attributes worthy of conservation. Therefore, 
conservation populations include both core populations (genetically 
pure), and populations that are less than 10 percent introgressed with 
other subspecies of cutthroat trout.
    We conducted our analysis on conservation populations because we 
found that Colorado River cutthroat trout with less than 10 percent 
introgression still express important behavioral, life-history, or 
ecological adaptations of the indigenous populations within the range 
of the subspecies, and remain valuable to the overall conservation and 
survival of the subspecies (Campton and Kaeding 2005, pp. 1323-1325).
    Hybridization is an important concern for CRCT populations. An 
introgressed population results when a nonnative species or subspecies 
is introduced into or invades the CRCT habitat, the two species then 
interbreed (i.e., hybridize), and the resulting hybrids themselves 
survive and reproduce. If the hybrids backcross with one or both of the 
parental species, genetic introgression occurs. Continual introgression 
can eventually lead to the loss of genetic identity of one or both 
parent species, thus resulting in a ``hybrid swarm'' consisting 
entirely of individual fish that often contain variable proportions of 
genetic material from both of the parental species.
    We have adopted the States' standards and consider all core and 
conservation populations, as defined under these standards and as 
described by Hirsch et al. (2006, p. 29), to be CRCT for purposes of 
this status review. Because the categories are nested, the term 
``conservation population'' includes the ``core populations,'' and we 
refer to them collectively as ``conservation populations'' in the 
remainder of this document.
    The greatest number of conservation populations occur in the Upper 
Green (76 populations) and Upper Colorado (75 populations) GMUs, 
occupying 1,532 km (952 mi) (Table 1). Most other conservation 
populations occur in the Yampa (53 populations), Lower Green (26 
populations) and Gunnison (25 populations) GMUs, occupying 1,188 km 
(738 mi). Smaller numbers of conservation populations occur in the 
Lower Colorado (14 populations), San Juan (12 populations), and Dolores 
(4 populations) GMUs, occupying 170 km (106 mi) (Hirsch et al. 2006, p. 
32). There are no conservation populations in Arizona or New Mexico.
    The 2006 Conservation Strategy lists 41 existing conservation 
populations in 455 hectares (1,123 acres) of lake habitat in 6 of the 
GMUs (CRCT Coordination Team 2006a, p. 6). The protocol used in the 
rangewide status report was not designed to address lake populations 
(Hirsch et al. 2006, p. iv). However, during the analysis, when a lake 
was connected to occupied stream habitat, it was included as stream 
miles in the rangewide status report, and 18 of the 41 lakes were 
included as 11 stream kilometers (7 stream miles). Lake populations are 
considered an important component in the conservation of CRCT, and some 
lakes are specifically designated to preserve genetically pure 
populations (CRCT Coordination Team 2006a, p. 17).
    While the Hirsch et al. (2006) report did not specifically analyze 
population trends, it gave some examples of previous assessments and 
the general portrayal of the previous status of the subspecies. For 
example, Binns (1977, pp. 7-16) found 40 streams in Wyoming occupied by 
CRCT, with 12 of those streams occupied by fish he considered 
genetically pure. The 2006 report identifies 85 conservation 
populations in Wyoming. The CRCT Conservation Team produced reports in 
1998, 2001, and 2003 that show stream conservation populations 
rangewide have increased from 161 populations in 1998 to 286 
populations in 2003 and lake populations increased from 12 populations 
in 1998 to 41 populations in 2003 (Hirsch et al. 2006, p. 62). In 
recent years more populations have been discovered, and other 
populations have been expanded or restored. Also, populations that 
previously were considered hybridized were found through genetic 
testing to be eligible to be added to the list of conservation 
populations.

Previous Federal Actions

    On December 16, 1999, we received a formal petition from the CBD 
and others to list the CRCT as threatened or endangered. On January 12, 
2000, we notified CBD that we could not immediately address the 
petition because of other higher priority listing activities. In 
October 2000, CBD filed a complaint in the U.S. District Court for the 
District of Columbia alleging that we had failed to make a timely 90-
day finding. We completed the 90-day review process and on April 20, 
2004, published a finding in the Federal Register (69 FR 21151) that 
determined the petition failed to present substantial information 
indicating that listing this subspecies may be warranted.
    After our 90-day finding was published, Plaintiffs amended their 
October 2000 complaint, alleging that we used the wrong procedures and 
standards to assess the petition. From approximately January 2002 
through April 2004 we received important information relevant to the 
status of CRCT from the wildlife departments of Colorado, Utah, and 
Wyoming, and from the National Park Service (NPS), BLM, and USFS. 
According to CBD's complaint, this information was used inappropriately 
in our 90-day finding because we only solicited information and 
opinions from limited outside sources.
    On September 7, 2006, the Court ruled in favor of the Plaintiffs 
and ordered us to produce a status review and 12-month finding for CRCT 
within 9 months. A notice was published in the Federal Register (71 FR 
65064) announcing the opening of a comment period from November 7, 
2006, to January 8, 2007. A public workshop was held on December 6-7, 
2006, to obtain additional information.

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Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533), and implementing regulations 
at 50 CFR part 424, set forth procedures for adding species to the 
Federal List of Endangered and Threatened Species. In making this 
finding, we summarize below information regarding the status and 
threats to this species in relation to the five factors provided in 
section 4(a)(1) of the Act.
    In response to our 2006 Federal Register notice, we received 
comments and information on CRCT from the States of Colorado, Utah, and 
Wyoming, as well as USFS, BLM, private citizens and organizations, and 
other entities. Among the materials that we received, the most 
important was a rangewide status report for CRCT (Hirsh et al. 2006). 
The Hirsh et al. (2006) status report is a comprehensive document 
covering the entire range of the CRCT.
    The CRCT rangewide status report (Hirsch et al. 2006) and the 
comprehensive database that is the report's basis, along with other 
supplemental submissions from the agencies and commenter, provide the 
best scientific and commercial information available that describes the 
current rangewide status of CRCT. The rangewide status report 
summarizes information provided by 48 fisheries professionals from 
Colorado, Utah, Wyoming, and New Mexico, including State wildlife 
agencies, USFS, BLM, and the Service (Hirsch et al. 2006, p. 1). 
Specific protocols were developed and the information was assembled in 
a Geographic Information System (GIS) database. A peer review was 
conducted of the report by five recognized experts in the field of 
fishery biology, conservation biology, and/or genetics. The results of 
the peer review found that overall the document provides sound 
scientific data to use as the basis for our 12-month finding.
    During the recent public comment period, we received comments from 
the petitioners (Greenwald 2007, pp. 2-3) recommending that we use the 
criteria developed to evaluate Rio Grande cutthroat trout (Oncorhynchus 
clarki virginalis) for evaluating CRCT. The Service finds that the 
criteria for the Rio Grande cutthroat trout were appropriate for that 
subspecies at the time of its candidate status review. However, at that 
time, a rangewide status assessment was not available for that 
subspecies. The Service finds that the most recent rangewide status 
report for CRCT (Hirsch et al. 2006) provides the best scientific 
information on the rangewide status of the subspecies. It provides a 
broad picture of the status of the subspecies without eliminating 
populations that may provide important resources for the conservation 
of the subspecies.
    In making this finding, we considered all scientific and commercial 
information that we received or acquired between the time of the 
initial petition (December 1999) and the end of the Status Review 
public comment period (January 8, 2007). We relied primarily on 
published and peer-reviewed documentation for our conclusions.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of the Species' Habitat or Range

    Most CRCT populations currently occupy lands administered by 
Federal agencies. Of the total 4,863 km (3,022 mi) of occupied habitat, 
including sport fish populations (includes all CRCT populations), 3,618 
km/2,248 mi (74 percent) are under Federal jurisdiction, with the 
majority occurring within National Forests (Hirsch et al. 2006, p. 27). 
National Forest wilderness areas have 750 km (466 mi) of CRCT habitat, 
and other National Forest lands have 2,494 km (1,550 mi) of habitat. 
The CRCT occupy 336 km (209 mi) of land administered by the BLM and 37 
km (23 mi) managed by the NPS.
    Land uses associated with each conservation population were 
identified in Hirsch et al. (2006, p. 50, Table 33), but the 
significance of the activities was not determined in relation to 
individual populations or the conservation of the subspecies. Non-
angling recreation (camping, hiking, ATV use, etc.) occurs in 73 
percent of the conservation populations, and angling occurs in 71 
percent of the conservation populations. Livestock grazing occurs in 68 
percent of the conservation populations, roads in 42 percent, timber 
harvest in 24 percent, and dewatering in 16 percent. A small percentage 
of populations have mining, nonnative fish stocking, hydroelectric 
plants or water storage, or other activities. Many populations have 
more than one land use occurring in the area.
    A comprehensive assessment of the effects of land management 
practices on CRCT does not exist. However, an evaluation of habitat 
quality was conducted for currently occupied habitat (Hirsch et al. 
2006, p. 23). The evaluation considered both natural habitat features 
and human disturbances, including land use practices. A stream ranked 
excellent if it had ample pool habitat, low sediment levels, optimal 
temperatures, and quality riparian habitat. Good habitat quality may 
have some attributes that are less than ideal, and fair habitat has a 
greater number of attributes that are less than ideal. Poor habitat 
quality is found where most habitat attributes reflect inferior 
conditions. Approximately 618 km/384 mi (13 percent of occupied 
habitat) (including sport fish populations) received an excellent 
habitat rating. Good habitat conditions were found in 1,419 km/882 mi 
of habitat (29 percent of occupied habitat) and fair habitat conditions 
were found in 2,276 km/1,414 mi of habitat (47 percent of occupied 
habitat). Poor conditions were found in 275 km/171 mi (5.7 percent of 
occupied habitat), and habitat conditions in 275 km/171 mi (5.7 
percent) were unknown. The majority of occupied habitat (89 percent) is 
considered in fair, good, or excellent condition, which indicates that 
current management practices under Federal land management agencies and 
other jurisdictions in general are maintaining habitat conditions that 
support CRCT.
    Livestock grazing occurs in the vicinity of over half of the CRCT 
populations. Appropriately managed livestock grazing can occur in the 
vicinity of CRCT habitat while maintaining habitat conditions that 
support CRCT. We recognize that overgrazing does cause adverse impacts 
to some individual populations of CRCT. However, only 5.7 percent of 
the occupied stream miles were considered to have poor habitat quality, 
according to the habitat evaluation in the rangewide status report 
(Hirsch et al. 2006, p. 23). Specific information on grazing impacts to 
CRCT habitat on a rangewide basis is not available. We did not receive 
information that led us to believe that overgrazing has caused declines 
in CRCT to the extent that it affects the rangewide status of the 
subspecies.
    Roads, timber harvest, dewatering, and other activities occur in 
the area of some CRCT populations. The presence of these activities may 
directly affect CRCT habitat in certain locations. However, the habitat 
quality evaluation (Hirsch et al. 2006, p. 23) indicates that most CRCT 
habitats are currently maintained in excellent, good, or fair 
condition, providing adequate habitat for the persistence of the 
subspecies throughout its current range.
    Oil and gas development has been accelerating over the last several 
years in Colorado, Utah, and Wyoming. Oil and gas development could 
affect CRCT through increased land disturbance from roads and pads that 
could cause increased sediment loads and water

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quality problems associated with discharge of produced water reaching 
CRCT habitat. The BLM provided maps overlaying CRCT conservation 
populations in Colorado and Wyoming with the occurrence of existing 
active and inactive wells and existing oil and gas leases on BLM, USFS, 
and other lands where BLM has jurisdiction over the subsurface mineral 
rights. The mapping analysis showed that there is very little overlap 
between oil and gas development sites and CRCT conservation 
populations. For the most part, CRCT populations occur at higher 
elevations where there is minimal oil and gas activity. Specific areas 
may have high potential for oil and gas development, such as the Roan 
Plateau in western Colorado (Upper Colorado GMU) and the Wyoming Range 
in Wyoming (Upper Green GMU). However, it does not appear that oil and 
gas development would impact a significant number of conservation 
populations to the extent of influencing the status of the subspecies. 
Where oil and gas development is proposed, the BLM is implementing 
measures to protect CRCT habitat. For example, the Roan Plateau Plan 
proposes special land use designations such as no ground disturbing 
activities and no surface occupancy for occupied and other high-value 
CRCT habitat; and Site-specific Relocation/Controlled Surface Use for 
the entire Parachute Creek Watershed Management Area (BLM 2006, pp. 2-
13).
    State and Federal agencies are implementing existing programs to 
restore and enhance CRCT habitat. Most of the 285 conservation 
populations (72 percent) have one or more restoration, conservation, or 
management activities either completed or currently being implemented 
within CRCT habitat (Hirsch et al. 2006, p. 50). One example is the 
Strategic Habitat Plan adopted by the Wyoming Game and Fish Commission 
in 2001 (WGFD 2007, p. 16), where habitat biologists work with 
landowners and land managers to manipulate habitat on a watershed 
scale, providing benefits to both terrestrial and aquatic wildlife 
resources. Even though the Strategic Habitat Plan was not officially 
adopted until 2001, many projects of this nature were already being 
implemented. An example is the Little Mountain project which has been 
ongoing for more than 12 years. This effort is an integrated watershed 
restoration project implemented in a 91,054-hectare (225,000-acre) 
watershed in the Upper Green River GMU. Habitat managers have used a 
variety of treatments, including 216 habitat improvement structures, 37 
km (23 mi) of fence, 860 trees planted, 12,910 hectares (31,900 acres) 
treated with prescribed fire, and 16 km (10 mi) of pipeline and 12 
stock tanks for livestock water development. As a result, stream 
mileage inhabited by CRCT in the project area tripled to 61 km (38 mi), 
while population densities increased by over 1,000 percent (WGFD 2007, 
pp. 17-18). Livestock grazing allotment buyouts also have been 
implemented under this program to reduce impacts of overgrazing and 
improve watershed conditions for CRCT (WGFD 2007, pp. 16-19).
    The CBD (Greenwald 2007, p. 7) submitted comments stating that 
impacts of livestock grazing, logging, water diversion, roads, and oil 
and gas drilling were extensively documented in their original 
petition. However, the analysis presented in the petition assumed that 
if a land management activity occurred in the vicinity of a CRCT 
population, the activity was adversely affecting the population. In our 
90-day finding, the Service recognized that overgrazing and other land 
management activities can be detrimental to trout habitat, and that 
overgrazing and other land management activities may occur in some 
habitats occupied by CRCT. The petition asserted that habitat 
conditions are degraded in a significant portion of the subspecies' 
range. According to Greenwald (2007, p. 7), the information presented 
in the petition clearly indicates that ongoing habitat degradation is 
threatening remaining CRCT populations. However, the petition used the 
habitat limitations data field presented in Appendix A of the 
Conservation Agreement and Strategy (CRCT Task Force 2001 pp. 38-49) to 
draw this conclusion. 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. In contrast with the CBD (Greenwald 
2007, p. 7), we found that the mere presence of an activity within a 
stream segment that hosts a conservation population is not sufficient 
evidence to conclude that the population is threatened. Additional 
parameters, such as distribution and abundance, and recent trends, must 
be factored into an overall status determination. Otherwise, logic 
would dictate that every species that comes into contact with managed 
landscapes is threatened by those human influences. Such a conclusion 
is not reasonable.

Summary of Factor A

    In summary, populations of CRCT that meet the State management 
agency standards as conservation populations (i.e., CRCT populations we 
are considering for the purposes of this finding) and are well 
distributed in the 8 GMUs (major watersheds). The major watersheds 
contain 42 HUCs (smaller watershed designations within each GMU) 
throughout CRCT native range. The majority of the conservation 
populations occur in the Upper Green and Upper Colorado GMUs, with a 
substantial number of conservation populations occurring in the Yampa, 
Lower Green, and Gunnison GMUs.
    Land use practices, such as livestock grazing, road maintenance, 
and timber harvest, are occurring in most areas of occupied habitat. 
However, habitat quality ratings of fair, good or excellent are being 
maintained in a large majority of CRCT habitat throughout the current 
range of the subspecies. The majority of the populations occur on 
Federal lands where land use regulations ensure maintenance of existing 
habitat (see Factor D), with restoration and enhancement projects 
occurring in the majority of these populations.
    Substantial numbers of CRCT conservation populations with adequate 
habitat conditions exist in the eight major GMUs of the upper Colorado 
River basin, collectively forming a solid basis for persistence of 
conservation populations of CRCT. Based on the present information, we 
conclude that the best scientific and commercial information available 
to us indicates that present or threatened destruction, modification, 
or curtailment of habitat or range has not affected the status of CRCT 
to the extent that listing under the Act as a threatened or endangered 
species is warranted at this time.

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

    No commercial harvest of CRCT currently occurs, so any potential 
overutilization would come from recreational angling. Data show that 
angling occurs in 71 percent of CRCT conservation populations (Hirsch 
et al. 2006, p. 50). Colorado, Utah, and Wyoming all have special 
regulations that provide protection against over-harvest of CRCT. These 
special regulations include catch-and-release requirements, very 
limited harvest, fishing closures, and tackle restrictions. Also, the 
remote location of many CRCT streams provides protection from heavy 
fishing pressure (CRCT Coordination Team 2006a, p. 10). Angling for 
CRCT is considered an incidental activity because most streams are 
small and difficult to access by vehicle, and adult fish are small due 
to the short growing

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season at high elevations (Fausch et al. 2006, p. 32)
    In Colorado, Administrative Directive W-6 classifies CRCT waters as 
``Native Fish Species Conservation Management,'' where the primary 
purpose of management is for native cutthroat recovery and 
conservation. Primary consideration is to protect the populations from 
pathogens and overfishing by implementing special regulations, which 
may include prohibiting angling where determined appropriate (CDOW 
2007, pp. 3-4). In Utah, several fishing regulations have been 
implemented to protect native cutthroat trout from overutilization. For 
example, Statewide trout bag and possession limits were reduced from 
eight fish to four, and short-term fishing closures were recently 
imposed to protect native cutthroat trout (Donaldson 2007, p. 3). 
Wyoming implements various angling restrictions to protect CRCT 
populations, such as complete fishing closures, catch and release only, 
reduced bag limits, seasonal closures, or tackle restrictions (WGFD 
2007, p. 23).
    Scientific collection of CRCT for scientific or educational 
purposes is controlled by a strict permitting process that prevents 
excessive sampling in Colorado, Utah, and Wyoming (CRCT Coordination 
Team 2006a, p. 10). Collection of fish tissue for genetic sampling is 
now conducted by non-lethal techniques.

Summary of Factor B

    In our 90-day finding (69 FR 21151), we concluded that angler 
harvest did not pose a significant threat to the continued existence of 
CRCT. We did not receive any new information during the status review 
to change this conclusion. As a result of this status review, we 
conclude that the best scientific and commercial information available 
to us indicates that overutilization for commercial, recreational, 
scientific, or educational purposes has not affected the status of CRCT 
to the extent that listing under the Act as a threatened or endangered 
species is warranted.

Factor C. Disease or Predation

Disease
    Disease risks are evaluated in the status report (Hirsch et al. 
2006, pp. 41-43). Diseases considered in this evaluation included 
whirling disease, along with several others. Risks are assessed based 
on proximity of disease-causing pathogens and their accessibility to a 
population. The majority of the populations (63 percent) are considered 
to have very limited risk from disease because disease and pathogens 
are not known to exist in the watershed, or a barrier is in place 
blocking upstream fish movement. In general, populations that are 
isolated have less risk of catastrophic diseases (Hirsch et al. 2006, 
p. 42). Only five populations are known to be currently infected with 
one of the identified diseases.
    In recent years, whirling disease has become of 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, pp. 317-325). However, Tubifex tubifex is usually most 
abundant in areas of high sedimentation, warmer water temperatures, and 
low dissolved oxygen. Most populations of CRCT occur in cold water 
stream habitats at high elevations, where the aforementioned conditions 
are unlikely to exist and where Tubifex tubifex is unlikely to be 
abundant. Thompson et al. (1999, pp. 317-325) found infection rates to 
be low when temperatures are less than 10 [deg]C (50 [deg]F). Out of 
the several hundred CRCT populations reported by the States, only a few 
populations of CRCT in Utah and Wyoming have been infected by whirling 
disease (Hirsch et al. 2006, p. 42).
    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 60 days of stocking 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 (Hebein et al. 
2007, pp. 10-12). Utah has some of the most stringent fish disease laws 
in the United States (Donaldson 2007, p. 4). Utah has a Fish Health 
Board that oversees the disease testing protocol. Utah does not allow 
fish that test positive for whirling disease to be stocked anywhere 
(Donaldson 2007, p. 4). UDWR is studying the effects of whirling 
disease on the few CRCT waters in Utah that have been infected by 
whirling disease (Donaldson 2007, p. 4). Wyoming has a policy that any 
fish testing positive for Myxobolus cerebralis will not be stocked 
(WGFD 2007, pp. 23-24).
Predation
    Where they occur in the same habitat, CRCT are often replaced by 
nonnative trout, primarily brook trout (Salvelinus fontinalis), but the 
degree to which predation is a factor in this replacement has not been 
well studied (Peterson et al. 2004, p. 755). The CDOW concluded that 
predation is not a factor for CRCT, because of the lack of large 
predatory fish, such as brown trout (Salmo trutta), lake trout 
(Salvelinus namaycush), or northern pike (Esox lucius) in CRCT habitat 
(Hebein et al. 2007, p. 12). We find that there is insufficient 
information to conclude that predation by nonnative fishes is a 
significant threat to CRCT.

Summary of Factor C

    The recent rangewide status report (Hirsh et al. 2006, p. 41) found 
only five CRCT populations currently infected with a significant 
disease, and only four additional populations to be at high risk for 
infection. As a result of this analysis, we conclude that the best 
scientific and commercial information available to us indicates that 
whirling disease or other disease organisms have not affected the 
status of CRCT to the extent that listing under the Act as a threatened 
or endangered species is warranted at this time. While nonnative fishes 
have been identified as a factor in the population dynamics of CRCT, 
very little specific information is available that describes how 
predation affects individual populations of CRCT. Fish surveys show 
that large predatory fish do not occur in CRCT habitat. Therefore, 
based on the available information, it does not appear that predation 
affects the status of CRCT to the extent that listing under the Act as 
threatened or endangered is warranted at this time.

Factor D. Inadequacy of Existing Regulatory Mechanisms

    The Act requires us to examine the adequacy of existing regulatory 
mechanisms with respect to those extant threats that place the species 
in danger of becoming either threatened or endangered. In the States of 
Colorado, Utah, and Wyoming, CRCT are considered a game species, and 
each State has specific regulations regarding catching CRCT by angling. 
The management authorities that develop and set the angling regulations 
typically do not own or manage the habitat in the watersheds inhabited 
by CRCT conservation populations. Most of that

[[Page 32595]]

habitat is managed by Federal land management agencies, primarily the 
USFS and BLM.
Regulatory Mechanisms Involving Land Management
    Numerous State and Federal laws and regulations are in existence 
that help to minimize adverse effects of land management activities on 
CRCT. Federal laws that protect CRCT and their habitats include the 
Clean Water Act, Federal Land Policy and Management Act, National 
Forest Management Act, Wild and Scenic Rivers legislation, Wilderness 
Act, and the National Environmental Policy Act. Approximately 74 
percent of CRCT habitat occurs on lands managed by Federal agencies. 
The majority of those lands are managed by the USFS. The CRCT occur in 
a large geographic area within the following National Forests: Arapaho-
Roosevelt, Grand Mesa-Uncompahgre-Gunnison, Medicine Bow-Routt, San 
Juan, White River, Manti-La Sal, Wasatch-Cache, Ashley, Dixie, and 
Bridger-Teton. Approximately 23 percent of USFS lands that have CRCT 
habitat are designated wilderness areas. Wilderness Areas and National 
Parks provide an extra level of protection for CRCT because many land 
management activities are prohibited in these areas. Regulatory 
mechanisms that address threats from pathogens and hybridizing 
nonnative fishes, such as fish stocking regulations, are addressed 
under Factors C and E.
    Other aquatic species listed under the Act do not overlap with the 
current range of the CRCT. The following four endangered fish species 
occur in the upper Colorado River basin in Colorado, Utah, Wyoming, and 
New Mexico: The Colorado pikeminnow (Ptychocheilus lucius), razorback 
sucker (Xyrauchen texanus), humpback chub (Gila cypha), and bonytail 
(Gila elegans). However, these species occur in the warm water reaches 
of the upper Colorado River basin and well downstream of any occurrence 
of CRCT. Water releases from upstream reservoirs as part of the 
recovery program to benefit the Colorado River endangered fishes would 
not flow through CRCT habitat. The threatened wetland plant, Spiranthes 
diluvialis (Ute ladies'-tresses orchid) and its potential habitat, 
occur in wetlands along the mainstem Green River in Colorado and Utah 
and the Yampa River in Colorado, outside the current range of CRCT.
U.S. Forest Service
    The USFS Sensitive Species policy in Forest Manual 2670 outlines 
procedures to address sensitive species. This policy is applied to 
projects implemented under the 1982 National Forest Management Act 
Planning Rule. The CRCT is designated a sensitive species by USFS 
Regions 2 and 4 where the Forests are operating under the forest plan 
for the 1982 Rule. However, in 2005, the USFS implemented a new 
planning rule (70 FR 1023, January 5, 2005), which directs Land 
Management Plans (LMPs) to be more strategic and less prescriptive. 
Under the new rule, LMPs identify ecosystem-level desired conditions 
and provide management objectives and guidelines to move toward the 
desired conditions (Troyer 2007, pp. 1-2). The LMPs also will provide 
species-specific direction for special status species when the broader 
ecosystem-level desired conditions do not provide for their needs.
    USFS Region 2 (which includes all Colorado National Forests and the 
Medicine Bow National Forest in Wyoming) applies practices outlined in 
their Watershed Conservation Practices Handbook to CRCT habitat (USFS 
2006, pp. 1-29). This handbook states that the USFS will apply 
watershed conservation practices to sustain healthy soil, riparian, and 
aquatic systems. The handbook provides Management Measures with 
specific design criteria to implement the management measures. For 
example, Management Measure No. 3 states: ``In the water influence zone 
next to perennial and intermittent streams, lakes, and wetlands, allow 
only those actions that maintain or improve long-term stream health and 
riparian ecosystem condition.'' In riparian areas and wetlands that are 
not meeting or likely to attain desired healthy condition, one design 
criteria to implement the Management Measure is to exclude livestock 
from areas where monitoring information shows that continued livestock 
grazing prevents attainment of those objectives. Implementation of such 
measures should maintain or enhance CRCT habitat.
    Greenwald (2007, p. 19) and Mueller (2007, pp. 1-2) submitted 
comments for this status review that assert that the National Forest 
Management Act and other laws are inadequate and their implementation 
is insufficient to provide necessary protections to CRCT on USFS lands. 
They express concern regarding the changes in Forest planning 
procedures between the 1982 National Forest Management Act Planning 
Rule and the 2005 Planning Rule and its ability to protect CRCT on USFS 
lands. We considered the changes in the planning process and found 
that, under the revised Forest Planning Regulations (70 FR 1023, 
January 5, 2005), CRCT are classified as a ``species of concern.'' This 
designation provides protections similar to those received for 
sensitive species and requires that LMPs include additional provisions 
to accommodate these species and provide adequate ecological conditions 
to continue to provide for the needs of CRCT. The USFS is required to 
develop a specific plan for CRCT for each LMP where the species occurs 
and project level analysis is required when a project is proposed in 
CRCT habitat. One component of the new planning process is the 
requirement for a monitoring plan. The purpose of the monitoring plan 
is to collect data at set intervals so that the USFS can evaluate 
progress toward achieving desired conditions, including conditions for 
species of concern, described in the LMP. A Comprehensive Evaluation 
Report is produced every five years that summarizes these data, 
identifies conditions and trends, and identifies the need for change.
Bureau of Land Management
    The CRCT is a designated sensitive species by the BLM in Colorado, 
Wyoming, and Utah. The BLM's policy for sensitive species offers the 
same level of protection as BLM's policy for candidate species. The 
policy reads as follows:

    For candidate/sensitive species where lands administered by the 
BLM or BLM authorized actions have a significant effect on their 
status, manage the habitat to conserve the species by:
    a. Ensuring candidate/sensitive species are appropriately 
considered in land use plans.
    b. Developing, cooperating with, and implementing range-wide or 
site-specific management plans, conservation strategies, and 
assessments for candidate/sensitive species that include specific 
habitat and population management objectives designed for 
conservation, as well as management strategies necessary to meet 
those objectives.
    c. Ensuring that BLM activities affecting the habitat of 
candidate/sensitive species are carried out in a manner that is 
consistent with objectives for managing those species.
    d. Monitoring populations and habitats of candidate/sensitive 
species to determine whether management objectives are being met.
National Park Service
    As stated in our 90-day finding, 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, p. 2). Five sites that contain 
core

[[Page 32596]]

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 do not occur in Rocky 
Mountain National Park.
Regulatory Mechanisms Involving Water Quantity
    An important regulatory mechanism controlled by the States is the 
implementation of instream flow regulations in CRCT habitat. In 
Colorado, the Colorado Water Conservation Board holds instream flow 
water rights for 8,539 stream kilometers (5,306 stream miles) in 915 
stream segments in the upper Colorado River basin in western Colorado. 
Approximately 55 percent of the conservation populations in Colorado 
are protected by instream flow rights and/or wilderness or national 
park designation, and an additional 38 percent are on an appropriation 
list for future protection through filing of instream flow water rights 
(Hebein et al. 2007, p. 15). The State of Wyoming has approved instream 
flow rights on 28 stream segments encompassing 187 km (116 mi) of CRCT 
habitat (WGFD 2007, p. 17).
    Greenwald (2007, p. 13) submitted comments for this status review, 
indicating that the Conservation Agreement and Conservation Strategy 
(CRCT Coordination Team 2006a, 2006b) are voluntary agreements that do 
not qualify as regulatory mechanisms. The Service agrees with that 
assessment and based its finding of the listing status of CRCT on the 
best available scientific and commercial information regarding the 
status and threats to CRCT, not on the promised or anticipated results 
of conservation actions.

Summary of Factor D

    Our status review has revealed information to indicate that 
regulatory mechanisms related to land management or fisheries 
management are effective, and will continue to be effective in 
protecting CRCT in the future. The USFS, BLM, NPS, Colorado, Utah, and 
Wyoming all have regulatory mechanisms in place that specifically 
protect CRCT. As a result of this status review, we conclude that the 
best scientific and commercial information available to us indicates 
that any identified inadequacies of existing regulatory mechanisms have 
not affected the status of CRCT to the extent that listing under the 
Act as a threatened or endangered species is warranted.

Factor E. Other Natural or Manmade Factors Affecting the Species' 
Continued Existence

Fragmentation and Isolation of Small CRCT Populations in Headwater 
Areas
    The majority of CRCT conservation populations (66 percent) occur as 
isolated, non-networked populations (Hirsch et al. 2006, p. 44). 
Another 72 populations (25 percent) are considered weakly connected, 
and 17 populations (6 percent) are considered moderately connected. 
Only eight populations have migratory forms present and open migration 
corridors so that they are considered strongly connected. The strongly 
connected populations occur in Utah and Wyoming in the Upper Green, 
Lower Green, and Yampa GMUs (Hirsch et al. 2006, p. 32). The CRCT 
Coordination Team (2006b, p. 8) defines metapopulations as a collection 
of localized populations that are geographically distinct but 
genetically interconnected through natural movement of individual fish 
between populations. Metapopulations are important because they 
maintain genetic exchange and increase genetic diversity. They also 
provide individuals to repopulate stream segments where populations are 
lost due to stochastic environmental events. While metapopulations are 
important in the overall status of the subspecies, they are at a higher 
risk for disease and invasion of nonnative fish.
    Some problems associated with small isolated populations are the 
increased risk of extirpation by catastrophic events and the loss of 
genetic exchange (CRCT Coordination Team 2006a, p. 9). Many populations 
occur in headwater streams where cold water temperatures and small 
stream size make habitat conditions less than optimal. In high 
elevation streams, cold summer water temperatures tend to delay 
spawning and these small stream often lack the deep water pools that 
are important to overwinter survival (Harig and Fausch 2002, pp. 545-
547).
    The small size of some CRCT populations is directly related to 
short stream segments where they occur. Through modeling, Hilderbrand 
and Kershner (2000, pp. 215-218) estimated minimum stream length for 
several subspecies of cutthroat trout 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 modeling found that 
streams thought to be below the population thresholds for long-term 
persistence based on minimum stream length have higher numbers of CRCT 
than originally predicted and that small increases in habitat length 
can produce a disproportionately greater increase in fish abundance 
(Young et al. 2005, p. 2406). Small, isolated populations have 
persisted for many years, such as above waterfalls and or in desert 
basins (Hilderbrand and Kershner 2000, p. 517). Specific criteria for 
population size to maintain viability has not been developed for CRCT 
(CRCT Coordination Team 2006a, p. 8).
    Small, isolated populations are at greater risk from stochastic 
events such as fire, floods, and drought that may threaten individual 
populations. However, widespread geographic distribution of CRCT in 
numerous individual populations mitigates the potential of future 
catastrophic natural events from affecting a large proportion of the 
populations. It is unlikely that a significant number of populations 
would be lost to the extent of affecting the overall status of the 
subspecies. Also, the fishery management agencies have the ability and 
management direction to reestablish CRCT populations in areas where 
they may be lost to natural catastrophic events. Wildfire is typically 
thought of as negatively affecting CRCT. However, where nonnative 
fishes occur in CRCT habitat, fire can present an opportunity to 
eliminate the nonnative fishes and provide an appropriate situation for 
reestablishment of CRCT (Hebein et al. 2007, pp. 16-17). New 
populations have been established in areas that were previously vacant 
such as above waterfalls and artificial barriers.
    Active programs are in place to restore metapopulations within the 
historic range of CRCT. For example the WGFD, UDWR, and USFS worked 
together to eliminate nonnative trout and restore CRCT in portions of 
the Gilbert Creek drainage in the Upper Green GMU. The project, 
completed in 2003, connected three populations and restored over 10 km 
(6.5 mi) of stream in Wyoming and several more in Utah (WGFD 2007, p. 
15).
    A general population health evaluation was conducted for all CRCT 
conservation populations (Hirsch et al. 2006, pp. 44-49). The 
evaluation was based on the following four health indicators: Temporal 
variability, population size, production potential, and population 
connectivity. Temporal variability looked at stream length to indicate 
patch size and resiliency. Population size of adults was used to 
estimate effective population size.

[[Page 32597]]

Production potential used growth and survival to estimate habitat 
quality, presence of nonnative fishes, disease, and land use impacts. 
Population connectivity identified the degree to which populations were 
networked or connected.
    The general health evaluation found that most of the conservation 
populations (69 percent) occur in stream reaches of less than 10 km (6 
mi) (Hirsch et al. 2006, pp. 44-49). About 25 percent of the 
conservation populations occupy stream reaches between 10 km (6 mi) and 
31 km (19 mi) in length, and 15 populations (5 percent) occupy stream 
reaches between 32 km (20 mi) and 64 km (40 mi). Two conservation 
populations (less than 1 percent) occupy stream reaches at least 80 km 
(50 mi) long. Evaluation of adult population estimates found that 12 
percent of the conservation populations have at least 2,000 adult CRCT. 
About one-third of the conservation populations had between 500 and 
2,000 fish, and another third had between 50 and 500 adult fish. The 
remainder of the populations had fewer than 50 adult fish. Most of the 
conservation populations (89 percent) were considered to be moderately 
healthy in terms of growth and survival, based on habitat quality, 
presence of nonnative trout, disease risk, land uses, and recovery 
actions. Composite scores of general health ranked the majority of 
populations with a moderately low level of general health primarily due 
to the number of small, isolated populations.
    The CRCT Conservation Team determined that it is important to 
incorporate two different conservation strategies (Hirsch et al. 2006, 
p. iv). One strategy emphasizes isolated populations because they are 
less susceptible to introgression, disease, and competition from 
nonnative fish. Multiple populations distributed throughout a watershed 
provide a mechanism for spreading risk because the simultaneous loss of 
all populations within the watershed is unlikely. A second strategy is 
to preserve and restore metapopulations to provide genetic exchange and 
allow for larger populations. Within the current range of CRCT both 
isolated populations and metapopulations are present, providing 
features for both conservation strategies.
Fisheries Management
    Since the late 1800s, fishery managers have implemented fish 
stocking programs that introduced nonnative salmonids into lake and 
stream habitats of CRCT. Nonnative rainbow trout have been introduced 
extensively throughout the range of CRCT, and they now compete and 
hybridize with CRCT. Stocking records from as early as 1885 from CDOW 
and the Service (formerly the U.S. Fish Commission) indicate that 
greenback cutthroat trout (Oncorhynchus clarki stomias), a subspecies 
known to occur in Colorado east of the continental divide in the South 
Platte and Arkansas River drainages, were raised in hatcheries and 
stocked in CRCT waters (Wiltzius 2007, pp. 1-22). These stocking 
records also indicate nonnative Yellowstone cutthroat trout 
(Oncorhynchus clarkii bouvieri) were stocked in CRCT waters. These 
subspecies of cutthroat trout are known to interbreed with CRCT. 
Nonnative brook trout also were stocked in the past for sport fishing 
purposes and are known to compete with CRCT. The numbers of kilometers 
where nonnative trout are present exceed the numbers of kilometers 
where records indicate nonnative trout stocking occurred in most areas, 
indicating that fish disperse to larger areas after stocking (Hirsch et 
al. 2006, pp. 25-26).
    Trappers Lake near the headwaters of the White River in Colorado 
had an endemic population of CRCT and was used to harvest eggs for 
routine stocking throughout Colorado by the CDOW (Martinez 1988, p. 
86). A hatchery was constructed on Cabin Creek, a tributary to Trappers 
Lake, and by the 1920s, 2 million eggs a year were taken and used for 
stocking programs in Colorado (Rogers and Wangnild 2005, pp. 1-2). In 
the 1930s, CRCT from Trappers Lake were planted in Lake Nanita in Rocky 
Mountain National Park and Williamson Lake in California, which remain 
today as sources of original Trappers Lake CRCT (Rogers and Wangnild 
2005, pp. 1-2). Trappers Lake was stocked with Yellowstone cutthroat 
trout between 1943 and 1950, and ``black-spotted trout'' (any 
combination of cutthroat trout, including hybrids) in 1952 and 1965 
(Martinez 1988, p. 86). Later, both rainbow trout and brook trout were 
introduced into Trappers Lake. Trappers Lake is no longer considered a 
pure population appropriate for providing a source of eggs for 
restoration, and spawning operations were suspended in 2000 (Rogers and 
Wangnild 2005, p. 2).
    Fish and wildlife agencies no longer stock nonnative trout in CRCT 
habitat (CRCT Coordination Team 2006a, p. 9). In some instances private 
parties may be illegally stocking waters with nonnative trout that 
compete with and/or hybridize with CRCT.
Competition From Introduced Brook Trout
    Competition from nonnative trout, especially brook trout, is 
recognized as a threat to CRCT (Behnke 1992, p. 54). Brook trout are 
the most common nonnative trout sympatric with CRCT populations (Hirsch 
et al. 2006, pp. 96-200). Studies have shown CRCT are displaced when 
brook trout occur in the same habitat (Peterson et al. 2004, p. 769). 
Recent studies have found that brook trout reduce recruitment of CRCT 
and reduce inter-annual survival of juvenile CRCT, which leads to 
reduction in population size of CRCT (Peterson et al. 2004, p. 769). 
Experiments where brook trout were removed from CRCT populations showed 
an increase in the survival of juvenile CRCT (Peterson et al. 2004, p. 
767).
    Brook trout are no longer stocked in CRCT waters in Colorado, Utah, 
or Wyoming. Ongoing programs are being implemented to remove brook 
trout by mechanical or chemical means from CRCT waters in all three 
States (Hebein et al. 2007, pp. 19-32; Donaldson 2007, p. 2; WGFD 2007, 
p. 9). In Utah, between 1992 and 2006, nonnative fish removal was 
conducted on almost 161 km (100 mi) of CRCT streams (Donaldson 2007, p. 
9). Approximately 30 percent (898 km [558 miles]) of stream kilometers 
that support CRCT conservation populations are sympatric with brook 
trout (Brauch 2007).
    Barriers have been constructed, or natural barriers exist, that 
protect CRCT populations from both brook trout invasion and 
hybridization threats from nonnative fishes. Complete barriers assist 
in protecting 139 conservation populations (49 percent) occupying 982 
km (610 mi) of stream, and partial barriers help protect 27 populations 
occupying 322 km (200 mi) of stream (Hirsch et al. 2006, p. 36). While 
barriers help protect populations from nonnative fish invasion, there 
are negative effects of installing barriers that must be considered, 
such as blocking fish movement and fragmenting habitat. Barrier 
placement may not be appropriate for all native cutthroat populations 
(Fausch et al. 2006, pp. 2-4).
Hybridization With Nonnative Fishes
    The scientific criteria for describing and formally recognizing 
taxonomic species of fish are based almost entirely on morphological 
characters (Behnke 1992, pp. 7-11). The advent of molecular genetic 
techniques in the mid-1960s added an additional set of biological 
markers that are used to distinguish species and subspecies of native 
trout in the western United States. In most native cutthroat trout 
genetic analyses to date, the molecular genetic data have confirmed the 
evolutionary distinctness among species and subspecies that had been 
described

[[Page 32598]]

taxonomically on the basis of morphology (Behnke 1992, pp. 7-11).
    Fish managers have commonly found that cutthroat trout populations 
that have introgressed at low levels, less than 10 percent 
introgression (UDWR 2000, pp. 1-9), with nonnative species or 
subspecies appear to retain morphological, behavioral, and ecological 
characteristics of their nonintrogressed ancestors. In addition, some 
published, peer reviewed studies have shown that individuals of a 
particular cutthroat trout subspecies may possess nuclear genes from 
another taxon detectable only by molecular genetic techniques, while 
still conforming morphologically, behaviorally, and ecologically to the 
scientific taxonomic description of the parental native species (e.g., 
Busack and Gall 1981, pp. 948-950; Weigel et al. 2002, pp. 397-401).
    We do not consider populations or individual fish conforming 
morphologically to the scientific taxonomic description of CRCT to be a 
hybridization threat to CRCT. Although such individuals may have genes 
from another taxon at low frequency (less than 10 percent), we are not 
aware of any information to suggest that such individuals express 
behavioral, ecological, or life-history characteristics differently 
than CRCT native to the particular geographic area. We expect the 
frequency of genes from the other taxon to remain low in the CRCT 
population for three reasons: (1) 89 percent of occupied habitat is in 
fair to excellent condition, which may provide an advantage for native 
CRCT survival (Busack and Gall 1981, pp. 948-950; Campton and Kaeding 
2005, pp. 1323-1324); (2) stocking of nonnative trout in CRCT habitat 
is no longer practiced by fish and wildlife agencies; and (3) 66 
percent of CRCT populations are isolated by human-caused or natural 
barriers, protecting them from increasing numbers of nonnative trout. 
If the populations or individual fish in question carry a low level of 
nonnative genetic material, they would be morphologically 
indistinguishable from CRCT, and therefore, any behavioral or life 
history attributes that might be inconsistent with what is normal for 
CRCT would be virtually impossible to detect. Furthermore, we have 
maintained that some introgressed populations may be valuable to the 
overall conservation and survival of a species or subspecies (Campton 
and Kaeding 2005, pp. 1323-1324; USFWS 2003, pp. 46992-46993).
    Our criteria for considering potentially introgressed populations 
of CRCT are consistent with a Position Paper titled ``Genetic 
Considerations Associated with Cutthroat Trout Management,'' developed 
by the fish and wildlife agencies of the intermountain western States 
(UDWR 2000, pp. 1-9). That document identifies, for all subspecies of 
inland cutthroat trout, three tiers of natural populations for 
prioritizing conservation and management options under the State fish 
and wildlife management authorities: (1) Core conservation populations 
composed of greater than 99 percent cutthroat trout genes; (2) 
conservation populations that generally ``have less than 10 percent 
introgression, but in which introgression may extend to a greater 
amount depending upon circumstances and the values and attributes to be 
preserved''; and (3) cutthroat trout sport fish populations that, ``at 
a minimum, meet the species'' (e.g., CRCT) phenotypic expression 
defined by morphological and meristic characters (counts of body parts) 
of cutthroat trout.'' Conservation populations of cutthroat trout also 
may include those believed to have uncommon, or important, genetic, 
behavioral, or ecological characteristics relative to other populations 
of the subspecies under consideration. Sport fish populations are those 
that conform morphologically (and meristically) to the scientific 
taxonomic description of the subspecies under consideration, but do not 
meet the additional criteria of ``conservation'' or ``core'' 
populations and hence are managed for their value as a sport fish 
population rather than their value to the conservation of the 
subspecies. The implicit premise of the Position Paper is that 
populations must conform, at a minimum, to the morphological and 
meristic charac