Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Bonneville Cutthroat Trout as Threatened or Endangered, 52235-52256 [E8-20674]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 73, Number 175 (Tuesday, September 9, 2008)]
[Proposed Rules]
[Pages 52235-52256]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E8-20674]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R6-ES-2008-0023; 1111 FY07 MO-B2]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Bonneville 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 on a petition to list the Bonneville cutthroat trout 
(Oncorhynchus clarkii utah) as a threatened subspecies throughout its 
range in the United States, pursuant to the Endangered Species Act of 
1973, as amended (Act). After a thorough review of all available 
scientific and commercial information, we find that listing the 
Bonneville cutthroat trout 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 concerning the status of or 
threats to the subspecies. This information will help us to monitor and 
encourage the conservation of the subspecies.

DATES: The finding in this document was made on September 9, 2008.

ADDRESSES: This finding is available on the Internet at https://
www.regulations.gov. Supporting documentation we used in preparing this 
finding is available for public inspection, by appointment, during 
normal business hours at the U.S. Fish and Wildlife Service, Utah 
Ecological Services Office, 2369 West Orton Circle, Suite 50, West 
Valley City, Utah 84119; telephone (801) 975-3330. Please submit any 
new information, materials, comments, or questions concerning this 
finding to the above address or via electronic mail (e-mail) at paul_
abate@fws.gov.

FOR FURTHER INFORMATION CONTACT: Larry Crist, Field Supervisor, U.S. 
Fish and Wildlife Service, Utah Ecological Services Office (see 
ADDRESSES section). If you use a telecommunications device for the deaf 
(TDD), call the Federal Information Relay Service (FIRS) at 800-877-
8339.

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 species are 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, that is, requiring a 
subsequent finding to be made within 12 months. Such 12-month findings 
must be published in the Federal Register.

Previous Federal Actions

    On February 26, 1998, we received a petition, dated February 5, 
1998, from the Biodiversity Legal Foundation requesting that the 
Service list the Bonneville cutthroat trout (Oncorhynchus clarkii utah) 
(BCT) as threatened in U.S. river and lake ecosystems where it 
continues to exist, and to designate its occupied habitat as critical 
habitat within a reasonable period of time following the listing. On 
December 8, 1998, we published a 90-day petition finding for the BCT in 
the Federal Register (63 FR 67640). We found that the petition 
presented substantial information indicating that the subspecies may be 
warranted for listing under the Act, and initiated a review of the 
subspecies' status within its historic range.
    In the 1998 90-day finding, we solicited additional data, comments, 
and suggestions from the public, other governmental agencies, the 
scientific community, industry, and other interested parties concerning 
the status of the BCT throughout its range. The comment period for 
submission of additional information ended on January 7, 1999, but was 
reopened (64 FR 2167) during January 13 through February 12, 1999. We 
published a 12-month finding in the Federal Register on October 9, 2001 
(66 FR 51362), and documented that the BCT was not warranted for 
listing under the Act because it was neither endangered nor likely to 
become endangered within the foreseeable future throughout all or a 
significant portion of its range.
    On February 17, 2005, we were sued by the Center for Biological 
Diversity, and others, on the merits of the 12-month finding. On March 
7, 2007, the District Court of Colorado dismissed the lawsuit after 
determining that Plaintiffs failed to demonstrate the not warranted 
finding was arbitrary, capricious, or contrary to law. The Plaintiffs 
appealed to the 10th Circuit Court of Appeals on May 4, 2007.
    On March 16, 2007, in the interim between the lawsuit dismissal and 
appeal, the Solicitor of the Department of the Interior issued a formal 
opinion regarding the legal interpretation of the term ``significant 
portion of the range'' of a species (DOI 2007). The opinion provides 
guidance on analysis intended to determine whether a species is in 
danger of extinction throughout a significant portion of its range when 
it is not in danger of extinction throughout its entire current range. 
Because this opinion was pertinent to the BCT decision, we withdrew the 
2001 12-month finding for BCT (USFWS 2007, entire), and initiated a new 
status review to include significant portion of the range analysis. We 
published a notice in the Federal Register (73 FR 7236) announcing the 
opening of a comment period from February 7 through April 7, 2008. The 
notice specified that the new status review would include consideration 
and analysis of all information previously submitted, and any new 
information provided regarding the status of the BCT.

Species Biology

    The BCT is native to the Bonneville basin, and is 1 of 14 
subspecies of cutthroat trout recognized by Behnke (1992, pp. 3-21, 
132-138) that are native to interior regions of western North America. 
BCT generally have large, evenly distributed spots, but a high degree 
of intra-basin variation exists. BCT tend to develop large, pronounced 
spots that are evenly distributed on the sides of the body rather than 
concentrated posteriorly as in the Yellowstone cutthroat trout 
(Oncorhynchus clarkii bouveri)

[[Page 52236]]

subspecies. Coloration in BCT is generally dull compared to other 
cutthroat subspecies; however, coloration can vary depending on 
environmental conditions and local genetic composition (Behnke 1992, 
pp. 132-138).
    Vertebrae typically number 62-63, slightly higher than in other 
subspecies. Scales in lateral series average 150-170. BCT average 
between 16-21 gill rakers, with a mean of 18-19, except the Snake 
Valley type, which have 18-24 (mean, 20-22). Another important 
characteristic of all cutthroat subspecies is the presence of 
basibranchial teeth, which are absent in rainbow trout (Behnke 1992, p. 
132). Numbers of basibranchial teeth provide information about 
subspecies derivation and relatedness. The Snake Valley type have 
profuse basibranchial teeth, averaging 20-28, while most other BCT 
average 5-10 (Behnke 1992, p. 132).
    Life strategies exhibited by BCT include stream resident (occupy 
home ranges entirely within relatively short reaches of streams), 
fluvial (migrate as adults from larger streams or rivers to smaller 
streams to reproduce), adfluvial (migrate, sometimes many kilometers, 
as mature adults from lakes to inlet or outlet streams to spawn), and 
lacustrine (lake) forms. The life strategy that a particular BCT 
population exhibits likely depends on a combination of environmental 
conditions and genetic plasticity of inherited traits. Very little 
information is available to suggest the extent of plasticity and what 
environmental characteristics may cue a successful shift in life 
strategy. Most information is based on the success or failure of 
transplants of various life forms among different aquatic ecosystems. 
Furthermore, evidence suggests that BCT populations within a single 
stream can comprise multiple life history strategies (resident, 
fluvial, adfluvial), and that individuals may use mainstem rivers to 
move between and among drainages where they are not fragmented by water 
diversions or barriers (Kershner et al. 1997, entire).
    May et al. (1978, p. 19) found that male BCT sexually matured at 
age 2 while females matured at 3 years of age. However, Bear Lake BCT 
were reported to mature much later, with adults normally beginning to 
mature at 5 years of age but not spawning until age 10 (Neilson and 
Lentsch 1988, p. 131). Both the age at maturity and the annual timing 
of spawning vary geographically with elevation, temperature, and life 
history strategy (Behnke 1992, p. 136; Kershner 1995, pp. 28-30). Lake 
resident trout may begin spawning at 2 years and usually continue 
throughout their lives, while adfluvial individuals may not spawn for 
several years (Kershner 1995, pp. 28-30). Annual spawning of BCT 
usually occurs during the spring and early summer at higher elevations 
at temperatures ranging from 4-10 [deg]C (May et al. 1978, p. 19). May 
et al. (1978, p. 19) reported BCT spawning in Birch Creek, Utah, 
beginning in May and continuing into June. BCT in Bear Lake began 
spawning in late April and completed spawning in June (Nielson and 
Lentsch 1988, p. 131). The wild broodstock at Manning Meadow Reservoir 
(9,500 feet elevation) spawn from late June to early July (Hepworth and 
Ottenbacher 1997, p. 1). In Lake Alice, Wyoming, fish were predicted to 
spawn from late May until mid-June (Binns 1981, p. 47).
    Fecundity of cutthroat is typically 1,200-3,200 eggs per kilogram 
(kg) (2.2 pounds (lbs)) of body weight (Behnke 1992, p. 33). In Birch 
Creek, a 147 millimeters (mm) (5.8 inches (in)) BCT female produced 99 
eggs, a 158 mm (5.8 in) female produced 60 eggs and a 176 mm (6.9 in) 
female produced 176 eggs (May et al. 1978, p. 19). Whereas in Raymond 
Creek, Wyoming, 3 females ranging from 124 to 246 mm (4.9 to 9.7 in) 
averaged 165 eggs (Binns 1981, p. 48). Evidence suggests fecundity of 
lake-dwelling BCT is greater. Fecundity of females in Lake Alice 
averaged 474 eggs/female (Binns 1981, p. 48), while females in Manning 
Meadow, Utah, averaged 994 eggs/female (D. Hepworth, Utah Division of 
Wildlife Resources, unpubl. data). Incubation times for wild BCT have 
not been verified, but Platts (1957, p. 10) suggested eggs hatch and 
fry begin to emerge approximately 45 days after spawning, depending on 
temperature.
    Larvae typically emerge in mid-to-late summer, depending on 
spawning times. Once emerged, larvae or fry, as they are commonly 
called, are poor swimmers and typically migrate to stream margins. 
Adfluvial BCT spend 1 or 2 years in streams before migrating to the 
Lake (Nielson and Lentsch 1988, p. 131).
    Growth of resident BCT is highly dependent on stream productivity. 
In general, growth of trout tends to be slower in high-elevation 
headwater drainages than in lacustrine environments, but this likely 
depends on temperatures and food base. In Birch Creek, Utah, age 1 fish 
averaged 84 mm (3.3 in), age 2 fish averaged 119 mm (4.7 in), age 3 
fish averaged 158 mm (6.2 in), and age 4 fish averaged 197 mm (7.8 in) 
in length (May et al. 1978, p. 17). Growth in two Wyoming streams was 
faster, and age 4 fish averaged 282 to 320 mm (11.1 to 12.6 in) in 
length (Binns 1981, p. 44). In contrast, BCT in Bear Lake grow to an 
average size of 560 mm (22.0 in) and 2 kg (4.4 lbs) (Nielson and 
Lentsch 1988, p. 131). Historic accounts of BCT in Utah Lake suggest 
fish may have reached a meter in length (Notes from Yarrow and Henshaw 
in 1872 as described by Tanner 1936). Platts (1957, p. 10) reported 
that some BCT taken from Utah Lake a century ago attained weights of 
over 11.3 kg (25 lbs).
    Little is known about feeding habits of BCT. In general, BCT trout 
are insectivorous, especially in stream habitats. Both terrestrial and 
aquatic insects appear to be important to their diet (May et al. 1978, 
pp. 7-10; Binns 1981, p. 48). In Birch Creek, May et al. (1978, pp. 9-
10) reported BCT diets were diverse in summer, while in the fall in 
Trout Creek, Utah, their diet consisted primarily of terrestrial 
insects. Dipterans and debris were the dominant food items for immature 
trout, while terrestrial insects were the dominant prey for mature 
individuals. BCT may display more plasticity in feeding habits 
depending on the system or specific population characteristics. Little 
information has been collected on BCT to understand the extent of 
feeding shifts of BCT. Platts (1957, p. 4) suggested that cutthroat do 
not need to feed on fish to attain large sizes but will do so where 
insects are not abundant.

Interactions With Nonnative Fish

    BCT may or may not persist when nonnative trout are stocked into 
BCT waters. The actual mechanism that dictates the survivorship of BCT 
in the presence of nonnatives is unknown, but the recent discovery that 
numerous BCT populations have persisted for decades in the presence of 
rainbow trout (Oncorhynchus mykiss), Yellowstone cutthroat trout, and 
other nonnatives suggests BCT is not always displaced by nonnatives as 
previously thought. However, BCT can hybridize with rainbow trout and 
Yellowstone cutthroats in some situations and be displaced by the 
superior competitor, brook trout (Salvelinus fontinalis). The degree of 
hybridization appears to vary with the persistence of the stocked fish 
and also with habitat conditions as does the level of competition with 
brook trout.
    Benhke (1992, p. 107) reported that BCT native to the Bear River 
drainage adapted to the harsh and fluctuating environments of desert 
basin streams, remaining the dominant trout today in many streams where 
nonnative trout were introduced. This seems to be a fairly unique trait 
of BCT compared to other cutthroat subspecies. There is still no 
specific rationale as to why BCT would persist better than other desert

[[Page 52237]]

cutthroat subspecies, yet something in its unique genetic composition 
seems to allow BCT to persist where other cutthroat subspecies have 
been found to be displaced.
    For example, Bear Lake BCT, probably due to the unique 
environmental conditions in which they developed, have resisted 
hybridization with and replacement by nonnative trout. Yellowstone 
cutthroat trout, Yellowstone cutthroat rainbow trout hybrids, and 
rainbow trout were consistently stocked into Bear Lake for decades. 
Benhke (1992, p.137) examined specimens from Bear Lake and compared 
these to museum specimens from the lake and with cutthroat trout from 
the Bear River drainage and found no evidence of hybridization among 
their taxonomic characters. Nielson and Lentsch (1988, p.130) similarly 
reported that, after examining the DNA of 52 Bear Lake specimens, no 
rainbow trout alleles were observed in any fish.
    Since the early 1990's, many additional remnant BCT populations 
have been found in streams that had been stocked with rainbow trout or 
Yellowstone cutthroat trout (Utah Division of Wildlife Resources, 
unpublished data). These BCT populations were assumed to be lost 
through hybridization until recent surveys found BCT present. Results 
of these surveys suggest BCT have retained much of their natural 
genetic integrity despite intensive nonnative stocking efforts.
    Introduced brook trout have been stocked, legally and illegally, 
into some BCT waters. BCT do not hybridize with brook trout, but brook 
trout are thought to acquire resources better and reproduce and recruit 
more efficiently than BCT. The specific mechanism of how brook trout 
displace BCT is unknown, but greater fecundity, earlier maturity, and 
tolerance of higher densities gives brook trout an advantage over the 
native BCT (Griffith 1988, p. 105; Fausch 1989, pp. 307-312). The 
extent of threat to BCT from brook trout varies depending on 
environmental conditions of the stream. Although not considered the 
greatest threat to the persistence of BCT, competition from introduced 
brook trout can and has displaced native BCT populations.

Habitat Requirements

    Trout, regardless of their evolutionary history, require 4 types of 
habitat during various stages of their life history: spawning habitat, 
nursery or rearing habitat, adult habitat, and overwintering habitat. 
Spawning gravels are required for spawning success and can be a 
limiting factor in high-gradient streams where the current carries off 
suitable spawning gravel (Behnke 1992, p. 25). Conversely, an even 
greater concern may be accumulation of fine sediments into interstitial 
spaces of spawning gravels, which prevents egg incubation and reduces 
larval survival. Such fines can become dominant in the sediments when 
poor land-use practices alter flow regimes, remove riparian vegetation, 
and/or degrade overall watershed conditions. These human-induced 
activities can aggravate already fragile soils and geology in 
vulnerable desert climates.
    Little information is available on specific habitat requirements 
for BCT; however, there is a wealth of information on salmonid habitat 
conditions in general which appear to generally represent those of BCT 
(Pennak and Van Gerpen 1947, entire; Binns and Eiserman 1979, entire; 
Scarnecchia and Bergersen 1987, entire). For example, well-oxygenated 
water, cooler temperatures in general and a complexity of instream 
habitat structure, such as large woody debris and overhanging banks, 
are considered good trout habitat conditions. For various species, 
subspecies, and local forms, adaptations and tolerance of these 
conditions varies. BCT have also been found to survive and be fairly 
robust in what is considered marginal salmonid habitat conditions 
(e.g., turbid water, fine sediments, warmer temperatures, poor 
structural habitat). This may be because BCT have evolved in a desert 
environment where climate can cause fluctuations in water and sediment 
regimes and environmental condition (Behnke 1992, p. 107).
    It was previously thought that with the exception of three 
lacustrine systems, Bear Lake (Utah and Idaho), Utah Lake, and Alice 
Lake (Wyoming), BCT were historically found in cool headwater streams 
throughout the Bonneville basin. However, more recent research and 
status and genetic surveys reveal BCT populations are found at high, 
moderate, and low elevations (within the range of elevations in the 
Bonneville Basin) in small headwater streams, such as those of the 
north slope of the western Uintas, to larger mainstem rivers, such as 
the Thomas Fork of the Bear River (UDWR, unpublished data).

Historic Habitat

    BCT likely historically occupied all suitable habitats within the 
Pleistocene Lake Bonneville basin, which included portions of Idaho, 
Nevada, Utah, and Wyoming. The desiccation of ancient Lake Bonneville 
about 8,000 years ago likely fragmented the BCT into remaining streams 
and lakes throughout the basin, resulting in several slightly 
differentiated groups of BCT, including: (1) The Bear River basin; (2) 
the Bonneville basin proper, including the Wasatch Mountain and Sevier 
River drainages; and (3) the Snake Valley, an arm of ancient Lake 
Bonneville that was isolated during an earlier desiccation event 
(Behnke 1992, pp. 132-138). There is general consensus among the 
scientific community, including the Service, that all these groups 
represent the BCT subspecies (Shiozawa 2008, p. 1). For the purposes of 
this finding, all three groups are considered BCT.
    The BCT Conservation Team, which includes biologists from Wyoming 
Game and Fish Department (WGFD), Utah Division of Wildlife Resources 
(UDWR), Nevada Division of Wildlife (NDOW), Idaho Department of Fish 
and Game (IDFG), Bureau of Land Management (BLM), U.S. Forest Service 
(USFS), the National Park Service (NPS), and the Service, completed a 
status report (May and Albeke 2005) that describes the rangewide status 
of BCT in the United States. The rangewide status report summarized the 
best available information on BCT (May and Albeke 2005, pp. i, 16, 103-
104). The status report was peer reviewed by five recognized experts in 
the fields of fishery biology, conservation biology, and genetics. The 
peer reviewers found that the status report provided sound scientific 
data to use in this 12-month finding.
    The 2001 finding on Bonneville Cutthroat Trout included 28,863 
hectares (71,322 acres) of lake habitat (indicated as an adfluvial life 
history) (USFWS 2001, pp. 34, 44, 50, 75). The 2005 BCT rangewide 
status report relied on a protocol that was not designed to address 
lake populations; however, 8 lakes connected to occupied stream habitat 
were included as 412 stream kilometers (km) (256 stream miles (mi)) 
(May and Albeke 2005, pp. 107, 110, 120). Thus, throughout the 
remainder of the document, all occupied BCT habitat is reported as 
stream habitat and includes lake populations. These lake populations 
are an important component in conserving BCT, and some lakes are 
specifically designated to preserve genetically pure populations 
(Donaldson 2008, pp. 8-9).
    The BCT Conservation Team's status report included an analysis of 
probable historic distribution (May and Albeke 2005, pp. 6, 16-19). Our 
understanding of BCT historic distribution is based on habitat thought 
to be occupied around 1800. The determination of occupation in this era 
was based on historic

[[Page 52238]]

climactic conditions, stream channel gradient, barriers that would 
preclude fish, and expertise of fishery biologists familiar with each 
watershed. The analysis resulted in 10,876 (km) (6,758 mi) of stream 
habitat potentially occupied historically (May and Albeke 2005, pp. 6, 
16-19). This analysis included estimated stream miles for historically 
occupied BCT lakes because the analysis protocol was not designed to 
address lake populations separately. The historically occupied habitat 
identified in each State included: Utah--7,916 km (4,919 mi) (73 
percent); Idaho--1,854 km (1,152 mi) (17 percent); Wyoming--974 km (605 
mi) (9 percent); and Nevada--132 km (82 mi) (1 percent) (May and Albeke 
2005, pp. 6, 16-19). The United States is divided and sub-divided into 
successively smaller hydrologic units that are classified into four 
levels: regions, sub-regions, accounting units, and cataloging units. 
Fourth-level hydrologic unit codes (HUCs) in the Lake Bonneville Basin, 
including Pine Valley, Tule Valley, Pilot-Thousand Springs, Northern 
Great Salt Lake Desert, Lower Beaver, and Sevier Lake, were not 
included as historical habitats because they were judged unsuitable due 
to extreme conditions, because information on them prior to 1800 is 
unavailable, or because historical records indicate that they were 
devoid of fish.

Current Distribution

    Current distribution of BCT is approximately 3,830 km (2,380 mi)--
35 percent of the probable historically occupied stream miles (May and 
Albeke 2005, p. 19). Currently occupied habitat identified in each 
State includes Utah--2,438 km (1,515 mi) (64 percent); Idaho--869 km 
(540 mi) (23 percent); Wyoming--476 km (296 mi) (12 percent); and 
Nevada--47 km (29 mi) (1 percent) (May and Albeke 2005, p. 19).
    The BCT is well distributed throughout its range in four watershed-
based GMUs (see Figure 1; Table 1 below). In earlier assessments, five 
GMUs or GUs (geographic units) were identified as including current 
populations of BCT; however, we combined the Bear Lake and Bear River 
GMUs because they occur within one watershed, and our analysis was 
conducted by watershed (May and Albeke 2005, pp. 4-5). This 
reconfiguration of GMUs does not imply a reduction in the geographic 
area where BCT occur (May and Albeke 2005, pp. 2-5).
    Within each GMU, streams were identified to the 4th-level 
hydrologic unit and assigned to a HUC. BCT occupy habitat in 22 of the 
23 HUCs determined to likely have supported historical habitat. BCT 
also occupy habitat in three HUCs that are either partially or totally 
outside of the subspecies historic range (May and Albeke 2005, pp. 19-
20); most of these populations were reintroduced into suitable habitat 
with no record of nonnative fish (Behnke 1992, pp. 134-135). The Bear 
River GMU has the greatest extent of currently occupied BCT habitat 
(2,010 km/1,249 mi), followed by the Northern Bonneville (1,532 km/952 
mi), Southern Bonneville (187 km/116 mi), and the West Desert (101 km/
63 mi).
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                          Table 1--From May and Albeke 2005, (p. 19), Table 21 (p. 34)
----------------------------------------------------------------------------------------------------------------
                                                                                                Km (mi) occupied
                                                         Km (mi) currently    Number of BCT          by BCT
                        GMU name                          occupied by BCT      conservation       conservation
                                                                               populations        populations
----------------------------------------------------------------------------------------------------------------
Bear River.............................................      2,010 (1,249)                 33      1,753 (1,089)
Northern Bonneville....................................        1,532 (952)                 65        1,318 (819)
Southern Bonneville....................................          187 (116)                 21           145 (90)
West Desert............................................           101 (63)                 34           101 (63)
                                                        --------------------------------------------------------
    Totals.............................................      3,830 (2,380)                153      3,316 (2,061)
----------------------------------------------------------------------------------------------------------------

Hybridization

    Hybridization is a concern for many cutthroat trout populations. An 
introgressed population results when a nonnative species or subspecies 
is introduced into or invades native cutthroat trout habitat, the two 
species then interbreed (i.e., hybridize), and the resulting hybrids 
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.
    Our criteria for considering the potential impact of introgressed 
populations of BCT 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 2000a, pp. 1-9). Signatories to the position paper 
include the IDFG, Montana Fish Wildlife and Parks, NDOW, New Mexico 
Game and Fish Department, UDWR, and WGFD. The document identified, for 
all subspecies of inland cutthroat trout, three tiers of natural 
populations for prioritizing conservation and management options under 
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 a species'' phenotypic expression defined by 
morphological and meristic characteristics (counts of body parts) of 
cutthroat trout.''
    The premise of the position paper on genetic considerations was 
that populations must conform, at a minimum, to the morphological and 
meristic characteristics of a particular cutthroat trout subspecies in 
order to be included in a State's conservation and management plan for 
that subspecies. Conservation populations of a cutthroat trout 
subspecies include fish believed to have uncommon or important genetic, 
behavioral, or ecological characteristics relative to other populations 
of the subspecies. Sport fish populations, conversely, while conforming 
morphologically (and meristically) to the scientific taxonomic 
description of the subspecies, do not meet the additional genetic 
criteria of conservation or core, and are managed for their value as 
sport fish rather than for conservation of the subspecies.
    Following the State management agencies' position paper (UDWR 
2000a, pp. 1-9), a ``core population'' is genetically unaltered (pure), 
and a ``conservation population'' is pure (a core population) or 
slightly introgressed (typically less than 10 percent) due to past 
hybridization, 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 
rainbow trout or other subspecies of cutthroat trout (May and Albeke 
2005, p. 71). The BCT rangewide status report (May and Albeke 2005, p. 
31) identified 153 stream populations (3,316 km/2,061 mi) as 
conservation populations (see Table 1, above, and Figure 2). Of the 153 
conservation populations, 73 (732 km/455 mi) are considered core 
populations containing genetically pure BCT.
    We consider all core and conservation populations, as defined under 
the States' standards and as described by May and Albeke (2005, p. 31), 
for purposes of conducting this status review. Because the categories 
are nested (conservation populations include core populations), we 
refer to them collectively as ``BCT conservation populations'' in the 
remainder of this finding. Some of the data presented in May and Albeke 
(2005) pertains to all BCT populations (including sport fish) or 
habitat. Those areas of this document that do not specify 
``conservation populations,'' therefore, are referring to all BCT 
populations. We conducted our analysis on conservation populations 
because we found that BCT with less than 10 percent introgression still 
express important behavioral, life history, or ecological adaptations 
of 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). (See also Factor 
E, Hybridization with Nonnative Fishes.)
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Conservation Populations

    Designated BCT conservation populations exist throughout the 
subspecies' historic range (May and Albeke 2005, p. 31)--in all four 
States and in the four designated GMUs. BCT currently occupy some 
habitat in 22 of the 23 HUCs historically occupied, and BCT that meet 
the conservation population definition (less than 10 percent 
introgressed) exist in 19 of those HUCs. BCT conservation populations 
were also identified in two HUCs (Spring-Steptoe and Hot Creek-Railroad 
Valley) outside historic range, and three additional conservation 
populations were identified outside historical range within the Upper 
Virgin HUC. The majority of conservation populations (65) occur in the 
Northern Bonneville GMU occupying 1,318 km (819 mi). The remainder of 
BCT conservation populations are relatively equally distributed among 
the West Desert (34), Bear River (33), and Southern Bonneville (21) 
GMUs. These populations occupy 101 km (63 mi), 1,753 km (1089 mi), and 
145 km (90 mi) respectively (May and Albeke 2005, p. 34).
    The majority of BCT conservation populations (101; 66 percent) 
occur as isolated, non-networked populations (May and Albeke 2005, p. 
34); 25 populations (16 percent) are weakly connected; 15 populations 
(10 percent) are moderately connected; and 12 populations (8 percent) 
have migratory forms and open migration corridors that make them 
strongly connected. The strongly connected populations occur in Utah, 
Idaho, and Wyoming in the Bear River Geographic Management Unit (GMU) 
and Northern Bonneville GMU (May and Albeke 2005, pp. 34, 107, 115, 
117).

BCT Population Trend

    BCT population trend and status can be interpreted from results of 
previous assessments conducted from the early 1970's through the 
present time. Hickman (1978, pp. 121-122) identified approximately 15 
populations he considered ``pure'' occupying approximately 34 km (21 
mi) of stream habitat. Duff (1988, pp. 121-127) reported 41 
``genetically pure'' BCT populations (39 stream populations) in 
association with 304 km (189 mi) of stream habitat. A draft Service 
status review that was never finalized reported 48 genetically pure BCT 
populations throughout the Bonneville Basin (USFWS 1993, pp. 1-62). 
Duff (1996, pp. 38-39) further refined his BCT population distribution 
reporting 81 genetically ``pure'' populations occupying 377 km (234 mi) 
of stream habitat. A Service status review found that BCT occupied a 
total of 1,372 km (852 mi) of stream habitat and 28,352 ha (70,059 
acres) of lake habitat totaling 291 populations (USFWS 2001, pp. iv-v).
    BCT assessments conducted between 1978 and 1996 generally counted 
populations that were thought to be genetically ``pure.'' The 2001 
Service assessment determined the genetic status of each population but 
was more inclusive and counted management, conservation, and potential 
conservation populations (USFWS 2001, pp. viii-xi). The May and Albeke 
(2005) assessment assessed the genetic status of each BCT population 
and then categorized genetic status based on the criteria in the 
State's genetic position paper (UDWR 2000a, pp. 1-9).
    Methods for tallying the number of individual BCT populations 
tended to vary by individual assessment, with earlier assessments 
tending to split tributary populations from mainstem river reaches. In 
contrast, methods used for the May and Albeke (2005, p. 64) assessment 
tended to group populations by higher order streams, thereby reducing 
the total count of populations. Thus, it is important to consider 
changes in the amount of occupied habitat when assessing population 
trends from different assessments rather than to simply rely on changes 
in number of populations. The number of known stream miles occupied by 
BCT conservation populations increased over time from 15 populations in 
34 km (21 mi) of habitat in 1978 to 153 populations in 3,316 km (2,061 
mi) in 2004. Some of the increase in BCT conservation populations and 
their habitat is the result of conservation actions such as the 
discovery of more populations in recent years; the expansion or 
restoration of populations; and the eligibility of populations for 
conservation status (through genetic testing) that were previously 
considered hybridized. Increases in the amount of BCT conservation 
population habitat is also due to the use of a more accurate GIS-based 
assessment method that incorporated the National Hydrography Dataset 
geodatabase (May and Albeke 2005, p. 2) and also the inclusion of lakes 
as river miles as used in the most recent assessment protocol (see 
above), although the increase due to the inclusion of lakes in the 
river mile calculation only accounts for an additional 412 km (256 mi) 
of stream habitat.
    The BCT Conservation Team's most recent analysis of the number of 
BCT conservation populations and the extent of their habitat indicates 
that conservation populations have increased from 153 populations in 
3,316 km (2,061 mi) in 2004 (May and Albeke 2005, p. 31), to 172 
populations in 3,333 km (2,071 mi) in 2008 (Burnett 2008a, entire). 
This most recent evaluation of the BCT Conservation Team's database was 
cursory and was not performed for other population parameters discussed 
in May and Albeke (2005) (i.e., restoration activities, genetic status, 
population health and densities, etc.); however, it does indicate that 
the number of BCT conservation populations and their habitat continue 
to increase.

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533), and implementing regulations 
at 50 CFR 424, set forth procedures for adding species to the Federal 
Lists of Endangered and Threatened Wildlife and Plants. In making this 
finding, we summarize information regarding the threats to the BCT in 
relation to the five factors provided in section 4(a)(1) of the Act.
    In making this finding, we considered all scientific and commercial 
information that we received or acquired up to the publication of the 
2001 12-month finding (66 FR 51362), and after publication of the 
notice initiating this finding (73 FR 7236; February 7, 2008). We 
relied primarily on published and peer-reviewed documentation for our 
conclusions, and most significantly, the rangewide status report 
competed by the BCT Conservation Team (May and Albeke 2005, entire).
    Pursuant to section (4) of the Act, a species may be determined to 
be an endangered or threatened species on the basis of any of the 
following five factors: (A) Present or threatened destruction, 
modification, or curtailment of habitat or range; (B) overutilization 
for commercial, recreational, scientific, or educational purposes; (C) 
disease or predation; (D) inadequacy of existing regulatory mechanisms; 
or (E) other natural or manmade factors affecting its continued 
existence. We evaluated whether threats to the BCT may affect its 
survival. Our evaluation of threats, based on the best scientific and 
commercial information available, is presented below.

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

    Land use activities associated with each BCT conservation 
population were

[[Page 52243]]

identified and documented in May and Albeke (2005, p. 52, Table 30), 
but the significance of the activities was not determined in relation 
to individual populations or to the conservation of the subspecies. 
Non-angling recreation (camping, hiking, ATV use, etc.) occurs in 69 
percent of the conservation populations. Livestock grazing occurs in 58 
percent of the conservation populations, roads in 69 percent, timber 
harvest in 20 percent, and dewatering in 30 percent. Hydroelectric 
plants, water storage, or flood control occurs in 20 percent of the 
conservation populations. A small percentage of populations have mining 
or nonnative fish stocking. Many populations have more than one land 
use occurring in the area.
    A comprehensive assessment of the effects of land management 
practices on BCT does not exist. However, an evaluation of habitat 
quality was conducted for currently occupied habitat (May and Albeke 
2005, p. 26). The evaluation considered both natural habitat features 
and human-caused disturbances. A stream ranked as ``excellent'' if it 
had ample pool habitat, low sediment levels, optimal temperatures, and 
quality riparian habitat. A ``good'' habitat quality rating indicated 
the presence of some less than ideal attributes, and ``fair'' indicated 
the presence of a greater number of less than ideal attributes. A 
``poor'' habitat quality rating indicated the inferior conditions of 
most habitat attributes. Of total occupied habitat for all BCT 
populations, excellent habitat conditions occurred in approximately 196 
km (122 mi) (5 percent); good conditions occurred in 1,801 km (1,119 
mi) (47 percent); fair conditions occurred in 1,080 km (671 mi) (28 
percent); poor conditions occurred in 628 km (390 mi) (16 percent), and 
unknown conditions occurred in 126 km (78 mi) (3.2 percent). The 
majority of occupied habitat (80 percent) is in fair, good, or 
excellent condition.
    Livestock grazing occurs in 58 percent of the BCT populations. 
Livestock grazing became an acute problem for watershed health in the 
late 1880s through 1930s when grazing, particularly sheep grazing, was 
so extensive and ill-managed that widespread watershed damage occurred 
throughout many areas in the Bonneville Basin. In fact, at the turn of 
the century, sheep were crowding cattle out of many areas (Peterson and 
Speth 1980, p. 179). In the Wasatch Mountains east of Salt Lake City, 
Utah, over-grazing of sheep denuded mountain meadows, some to the 
extent that watersheds experienced massive soil loss, land-slides and 
severe erosional damage. In addition to resident sheep, Utah was at a 
geographical `crossroads of the west' where hundreds of sheep were 
trailed to and from neighboring States (Peterson and Speth 1980, p. 
179).
    Overgrazing by sheep can be particularly damaging to overall 
watershed conditions. Sheep have been known to graze vegetation down to 
dirt and ``grub'' away at grass roots thereby damaging the soil mantle, 
which acts to hold water for plant uptake (Peterson and Speth 1980, 
p.180). The extensive watershed damage typical of over-grazing sheep in 
the early 20th century led to massive soil erosion, land slides, and 
flooding during heavy precipitation (Cottam 1947, pp. 23-29). Such 
events can completely eliminate local fish populations and undoubtedly 
affected local populations of BCT. For streams already fragmented from 
diversions or dewatering, such events could have led to local 
extirpation of BCT where no connected populations were available to 
recolonize streams after a catastrophic flood.
    Although cattle grazing can affect watershed conditions as well, 
the greater concern for cattle grazing stems from direct stream impacts 
where cattle are permitted to dwell in or are trailed through stream 
channels and riparian areas. Without adequate management, cattle can 
trample and destroy instream habitat and stream banks. They forage on 
lush riparian vegetation, which leads to degraded stream conditions and 
changes in channel morphology. Trampling destroys undercut banks 
resulting in wider and shallower channel morphology. Where this occurs, 
BCT can be impacted by increased water temperatures, loss of habitat 
complexity, altered macroinvertebrate food-base, and increased 
deposition of fine sediment (Platts 1991, p.393; Belsky et al. 1999, 
p.420; Rinne 1999, p.14).
    When livestock grazing is managed appropriately, it can occur in 
the vicinity of stream and riparian habitat, and habitat conditions 
that support fish populations can still be maintained (Fitch and Adams 
1998, p. 197). The Western Watersheds Project, Inc. (Carter 2008, pp. 
1-7) submitted information documenting grazing impacts in localized 
areas in the Bear River GMU. Much of the information documents range 
conditions relative to grazing allotment reauthorizations. The 
information and conclusions presented included the assumption that, if 
a land management activity occurred within the vicinity of a BCT 
population, it was adversely affecting the population. We recognize 
that overgrazing can cause adverse impacts to individual populations of 
BCT. However, only 16 percent of the occupied stream miles have poor 
habitat quality (May and Albeke 2005, p. 26). Specific information on 
grazing impacts to BCT habitat on a rangewide basis is not available. 
We found no information indicating that overgrazing significantly 
affects the rangewide status of BCT now, or will do so in the 
foreseeable future. Therefore, we conclude that overgrazing is not a 
significant threat to BCT.
    Roads, timber harvest, and dewatering occur in the area of some BCT 
populations. Similar to water development and grazing, the greatest 
impacts from timber harvesting occurred from 1850 to 1950. Although 
timber harvesting still occurs on National Forest Lands and very 
limited private lands in the Bonneville Basin, and may have some 
detrimental impacts on streams and watersheds, timber harvesting 
standards have substantially improved, particularly regarding 
protection of streams and watershed condition, and the catastrophic 
destruction that occurred in the first 100 years of pioneer settlement 
no longer occurs.
    Currently, timber harvesting affects BCT through the indirect 
effects of road building and deforestation. Road building is known to 
add fine sediment to streams where roads cross or follow stream 
channels. These fine sediments can fill interstitial spaces important 
for successful spawning and survival of eggs and larval fish as well as 
alter the macro-invertebrate food base (Williams and Mundie 1978, 
p.1032-1033). Deforestation can also add sediment input into streams 
where riparian buffers are not implemented. Loss of trees also 
increases water volume draining into stream channels, which can alter 
flow and sediment regimes or exacerbate catastrophic flooding during 
extreme precipitation events.
    Within the Bonneville Basin, timber harvesting is fairly limited 
compared to other areas of the inland west, mainly because the arid 
climate is not conducive to extensive, lush forests. Timber harvest 
occurs in only 20 percent of BCT conservation population habitat (May 
and Albeke 2005, p. 52, Table 30). We found no information indicating 
that timber harvesting significantly affects the rangewide status of 
BCT now, or will do so in the foreseeable future. Therefore, we 
conclude that timber harvesting is not a significant threat to BCT.
    Direct effects of water diversions and depletions (dewatering) on 
BCT occur where reaches are dewatered or made inaccessible by instream 
barriers. Secondary effects of water development may include higher 
water temperatures

[[Page 52244]]

in summer months because of lower water volume and diminished riparian 
condition and altered instream and shoreline habitat, all of which can 
impact cutthroat trout spawning and populations (Clancy 1988, pp. 40-
41). Dewatering occurs in only 30 percent of BCT conservation 
population habitat (May and Albeke 2005, p. 52, Table 30). Rates of 
habitat loss through water diversions and depletions were likely 
heaviest for the decades immediately after pioneer settlement, in the 
late 1800s, throughout the Bonneville Basin near locations of 
population growth. We found no information indicating that dewatering 
significantly affects the rangewide status of BCT now, or will do so in 
the foreseeable future. Therefore, we conclude that dewatering is not a 
significant threat to BCT.
    Idaho and Nevada have no producing oil or gas wells in BCT areas. 
However, oil and gas development has been accelerating over the last 
several years in Utah and Wyoming. Oil and gas development could affect 
BCT through increased land disturbance from roads and pads that could 
cause water quality problems associated with increased sediment loads, 
and through leaks, spills, and discharge of produced water reaching BCT 
habitat (WGFD 2004, pp. 25-26). The BLM and Utah Division of Oil Gas 
and Mining provided information on locations of existing active and 
inactive wells and oil and gas leases on BLM, USFS, and other lands 
where BLM has jurisdiction over the subsurface mineral rights within 
the BCT range in Utah and Wyoming (BLM 2008a, entire; UDOGM 2008, 
entire). A well exists within 1.6 km (1 mi) or less of 26 BCT 
conservation populations (17 percent of all conservation populations). 
Of these 26 populations, 2 were near active or producing wells; the 
wells near the remaining 24 populations were non-producing and were 
shut-in, plugged and abandoned, or abandoned entirely for development. 
These non-producing wells have a greatly reduced likelihood of 
releasing oil and gas related contaminants into BCT habitat (BLM 2008b, 
entire). Relatively little overlap exists between oil and gas 
development sites and BCT conservation populations. BCT populations 
typically occur at higher elevations where minimal oil and gas activity 
exists. An analysis of potential future oil and gas development for the 
States of Wyoming and Utah indicates that the majority of leases occur 
outside the historic range of BCT (BLM 2008b, entire). Potential 
impacts to BCT resulting from oil and gas development on Federal land 
are typically assessed through the National Environmental Policy Act 
(NEPA) review process; as a result, future effects should be disclosed 
and effects to BCT will have to be taken into consideration due to the 
sensitive species management status of BCT on Federal land. Therefore, 
based on the best scientific and commercial information available, we 
conclude that dewatering is not a significant threat to BCT now, or in 
the foreseeable future.
Summary of Factor A
    Land use practices, such as livestock grazing, road construction 
and maintenance, dewatering, and timber harvest, are occurring to some 
extent in most areas of occupied habitat. However, habitat quality 
ratings are fair, good, or excellent in 80 percent of BCT habitat 
throughout the current range of the subspecies. Approximately half of 
all BCT populations (49 percent) occur on Federal lands where land use 
regulations are in place to ensure ongoing maintenance of existing 
habitat (see Factor D). Restoration and conservation activities are 
occurring for at least 57 percent of the conservation populations.
    We find that the presence alone of an activity within a stream 
segment containing a conservation population is not sufficient evidence 
to conclude that the population is threatened or that a certain land 
use activity affects all populations rangewide at a significant level. 
Additional parameters, such as magnitude of impacts, distribution and 
abundance of BCT populations, and population trends, lend to an overall 
status determination. Many species exist in managed landscapes; not all 
are significantly impacted by human-caused influences to the level of 
being considered threatened under the Act.
    BCT conservation populations are well distributed in four GMUs, 
collectively forming a solid basis for persistence of BCT. These GMUs 
contain 19 of the 23 HUCs determined to have supported historical BCT 
habitat. In addition, BCT conservation populations currently occupy 
habitat in three HUCs that are either partially or totally outside the 
subspecies' historic range.
    Based on the best scientific and commercial information available, 
we conclude that BCT is not now or in the foreseeable future, 
threatened by destruction, modification, or curtailment of its habitat 
or range 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 BCT currently occurs, so only recreational 
angling could potentially result in overutilization. Data show that 
angling occurs in 60 percent of BCT conservation populations (May and 
Albeke 2005, p. 52). Utah, Idaho, and Wyoming have special regulations 
providing protection against over-harvest of BCT. These special 
regulations include catch-and-release requirements, limited harvest, 
fishing closures, and tackle restrictions. In addition, the remote 
location of many BCT streams provides protection from heavy fishing 
pressure (NDOW 2006, p. S-28; Baker et al. 2008, p. 29; Donaldson 2008, 
p. 3).
    The State of Idaho implements several fishing regulations to manage 
potential angler impacts in State waters. For most streams able to 
support larger fish, bag limits are 2 fish greater than or equal to 40 
centimeters (cm) (16 in) in length. In smaller streams, where BCT 
typically do not exceed 30 cm (12 in), the general stream limit is 2 
fish, and no size constraints exist. In other waters, seasonal angling 
restrictions or catch-and-release-only regulations are implemented 
(IDFG 2008, pp. 3, 19). In Utah, several fishing regulations protect 
native cutthroat trout from overutilization. The State reduced trout 
bag and possession limits from eight fish to four, and imposed short-
term fishing closures to protect native cutthroat trout (Donaldson 
2008, p. 3). Wyoming implements angling restrictions, such as size 
limits, reduced bag limits, and tackle restrictions to protect BCT 
populations (WGFD 2008, p. 8). Many of Nevada's BCT populations occur 
in remote areas, which provide protection from heavy fishing pressure 
(Baker et al. 2008, p. 29). None of the four States considers angling, 
under their current regulations, to be a threat to the subspecies.
    Collection of BCT for scientific or educational purposes is 
controlled by strict State permitting processes that prevent excessive 
sampling throughout its range in Utah, Wyoming, Idaho, and Nevada. 
Collection of fish tissue for genetic sampling is conducted by 
nonlethal techniques (Rogers 2007, pp. 1-3).
Summary of Factor B
    No commercial harvest of BCT currently occurs. Only recreational 
angling could potentially result in overutilization. However, Utah, 
Idaho, and Wyoming have special regulations

[[Page 52245]]

providing protection against over-harvest of BCT. Also, in our 2001 12-
month finding (66 FR 51362), we concluded that angler harvest did not 
pose a significant threat to the continued existence of BCT, and we 
know of no new information during development of this finding to change 
this conclusion. Collection of BCT for scientific or educational 
purposes is controlled by strict State permitting processes throughout 
the range of the subspecies. Therefore, we conclude that the best 
scientific and commercial information available indicates that 
overutilization for commercial, recreational, scientific, or 
educational purposes is not a significant threat to BCT now, or in the 
foreseeable future.

Factor C. Disease or Predation

Disease
    The BCT Conservation Team evaluated disease in the BCT status 
report (May and Albeke 2005, pp. 11-12, 40-42). Diseases considered had 
the potential to cause significant impacts to population health and 
included, but were not limited to, whirling disease, infectious 
pancreatic necrosis virus, and furunculosis. The BCT Conservation Team 
assessed risks based on proximity of disease-causing pathogens and 
their accessibility to a population. The majority of the populations 
(63 percent) have limited risk because disease and pathogens are not 
known to exist in the watershed, or a barrier blocks upstream fish 
movement. In general, isolated populations have less risk of 
catastrophic diseases. Fourteen populations (9 percent) are currently 
known to be infected with one of the identified diseases (May and 
Albeke 2005, pp. 40-41).
    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 1950's and requires 
two separate host organisms to complete its life cycle. Its essential 
hosts are a salmonid fish and an aquatic worm, Tubifex tubifex. 
Juvenile, sub-adult, and adult life stages of BCT have been shown to be 
susceptible to whirling disease in the Logan River, and some Logan 
River study sites exhibit a downward trend in BCT abundance (Budy et 
al. 2005, pp. xi-xiii). Despite this, BCT in the Logan River 
demonstrate high growth and survival rates and are generally in 
relatively good health. Logan River tributaries are important refuges 
from whirling disease-infected areas in the Logan mainstem (Budy et al. 
2005, pp. xi-xiii). Tubifex tubifex is most abundant in areas of high 
sedimentation, warmer water temperatures, and low dissolved oxygen. 
Most populations of BCT occur in cold water stream habitats at high 
elevations, where Tubifex tubifex is less likely to be abundant.
    All four States have developed management activities to protect BCT 
populations from whirling disease. Though whirling disease is known to 
occur in some Nevada waters, it currently does not pose a threat to BCT 
populations because it occurs at low levels among BCT populations (NDOW 
2006, pp. S27). Regardless, Nevada is in the process of formalizing 
protocols for BCT reintroductions and transplants relating to disease 
certification and broodstock management (NDOW 2006, pp. S27, S32). 
Idaho has outlined several strategies to protect BCT populations from 
the negative effects of disease. Strategies include monitoring fish 
populations for disease, prohibiting importation of fish and wildlife 
that carry disease risk, and ensuring that stocking, translocation, and 
propagation of fish do not contribute to the transmission or 
introduction of diseases (IDFG 2008, p. 14). Utah has some of the most 
stringent fish disease laws in the United States, which do not allow 
the stocking of fish that test positive for whirling disease (Donaldson 
2008, pp. 4-5). UDWR is studying the effects of whirling disease in a 
portion of BCT occupied waters in Utah that have been infected 
(Donaldson 2008, p. 4). Wyoming has a policy of not stocking fish that 
test positive for Myxobolus cerebralis (WGFD 2008, p. 9).
Predation
    Of the 153 conservation populations identified in the rangewide BCT 
status report, 97 (63 percent) had no interaction with nonnative fish 
and 56 (37 percent) were sympatric with nonnative fish (May and Albeke 
2005, p. 31). All BCT conservation populations sympatric with nonnative 
fish are located in the Bear River and Northern Bonneville GMUs. In 
these GMUs, BCT can be replaced by nonnative trout, but the degree to 
which predation is a factor in this replacement has not been well 
documented (Holden et al. 1997, pp. 3-21). Although nonnative fish can 
have negative effects on BCT in localized areas due to predation, 
research in the Logan River drainage shows that it is possible for BCT 
populations to persist in the presence of predacious nonnative fish 
(Behnke 1992, p. 107; Budy et al. 2005, pp. xi-xiii).
    Predation can affect BCT, mainly during early life stages, where 
other predaceous fish occupy the same area (UDWR 2000b, p. 48). Utah 
has implemented several management actions intended to alleviate 
potential predation of BCT by nonnative trout, including: nonnative 
removal/barrier installation projects; barring nonnative cutthroat 
stocking in conservation drainages; increasing angler harvest limits 
for brook trout in the Boulder and Uinta Mountains; and initiating 
fisheries research work (Donaldson 2008, pp. 5-7). Nevada has virtually 
eliminated threats to BCT from nonnative fish by utilizing barriers and 
nonnative removal restoration projects (Baker et al. 2008, pp. 3-5; 
NDOW 2006, p. S-27).
    Similar to Utah, Idaho and Wyoming have enacted management actions 
intended to alleviate potential predation of BCT by nonnative trout. 
Idaho has discontinued stocking brook trout into native trout streams, 
increased the daily limit for brook trout from 6 to 25, and removed or 
suppressed nonnative trout species that compete with BCT (IDFG 2008, 
pp. 6-7). Wyoming is monitoring BCT populations to ensure that 
nonnative populations do not become established in new waters in the 
Bear River drainage, have ceased stocking nonnative trout in waters 
managed for BCT conservation populations, and have implemented 
nonnative removal/barrier installation projects to control nonnative 
fish in BCT habitat (Emmrich 2008, p. 2; WGFD 2008, p. 10).
Summary of Factor C
    Only 14 (9 percent) BCT conservation populations are infected with 
a significant disease, and no additional populations are at high risk 
for infection (May and Albeke 2005, pp. 40-41). Therefore, we conclude 
that the best scientific and commercial information available indicates 
that neither whirling disease nor other disease organisms significantly 
threaten BCT now, or in the foreseeable future.
    Predation by nonnative fish, the primary source of predation on 
young BCT, may have some effect on BCT populations in the Bear River 
and Northern Bonneville GMUs. However, 63 percent of conservation 
populations have no interactions with nonnative fish. Also, research 
shows that it is possible for BCT populations to persist in the 
presence of predacious nonnative fish (Behnke 1992, p. 107; Budy et al. 
2005, pp. xi-xiii). State fish and wildlife agencies continue to 
implement management actions intended to alleviate potential predation 
of BCT by nonnative fish. At this time, we know of

[[Page 52246]]

no information that indicates to us that predation significantly 
affects BCT now, or in the foreseeable future.

Factor D. Inadequacy of Existing Regulatory Mechanisms

    The Act requires us to examine the adequacy of existing regulatory 
mechanisms with respect to extant threats that place the subspecies in 
danger of becoming either threatened or endangered. Regulatory 
mechanisms affecting BCT fall into three general categories: angling, 
land management, and water quantity.
Angling
    The States of Utah, Idaho, Nevada, and Wyoming consider BCT a game 
species, and each State has specific regulations regarding catching BCT 
by angling. We concluded above that recreational angling is not a 
significant threat to BCT, now or in the foreseeable future (see Factor 
B).
Regulatory Mechanisms Involving Land Management
    Numerous State and Federal laws and regulations help reduce adverse 
effects of land management activities on BCT. Most habitat in 
watersheds inhabited by BCT conservation populations is managed by 
Federal land management agencies, primarily the USFS and BLM, and to a 
limited extent the NPS. Federal laws that reduce impacts to BCT and 
their habitats include the Clean Water Act, Federal Land Policy and 
Management Act, National Forest Management Act, Wilderness Act, and 
National Environmental Policy Act. Approximately 49 percent of all 
occupied BCT habitat (including both sport fish and conservation 
populations) occurs on lands managed by Federal agencies, and the USFS 
manages the majority (May and Albeke 2005, p. 29). Of the 3,830 km 
(2,380 mi) of occupied habitat, 1,867 km (1,160 mi) are under Federal 
jurisdiction and the majority occur on National Forests (1,209 km (751 
miles)) (May and Albeke 2005, p. 29); these figures include sport fish 
populations because figures for conservation populations alone are not 
available (see Table 2 below). BCT occur in a large geographic area 
within the following National Forests: Bridger-Teton, Caribou-Targhee, 
Dixie, Fishlake, Humboldt-Toiyabe, Uinta, and Wasatch-Cache. BCT occupy 
11 km (7 mi) of land administered by the BLM, and 7 km (4.4 mi) managed 
by the NPS. Approximately 657 km (408 mi) of occupied BCT habitat 
occurs in wilderness areas managed by the USFS or BLM. Wilderness Areas 
and National Parks provide an extra level of protection for BCT because 
many land management activities are prohibited in them.

                                      Table 2--BCT Occupied Land Ownership
                [Numbers include areas occupied by both sport fish and conservation populations]
----------------------------------------------------------------------------------------------------------------
                                                                   USFS and BLM
              USFS                      BLM             NPS         Wilderness      Non-federal        Total
----------------------------------------------------------------------------------------------------------------
1,209 km........................           11 km            7 km          657 km        2,603 km        3,830 km
(751 mi)........................          (7 mi)        (4.4 mi)        (408 mi)      (1,618 mi)      (2,380 mi)
----------------------------------------------------------------------------------------------------------------

U.S. Forest Service
    The USFS Sensitive Species Policy in Forest Manual 2670 outlines 
procedures for conserving sensitive species. The policy applies to 
projects implemented under the