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Endangered and Threatened Wildlife and Plants: 12-Month Finding for a Petition To List the Bonneville Cutthroat Trout as Threatened Throughout Its Range

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Fish and Wildlife Service, Interior.


Notice of 12-month petition finding.


We, the Fish and Wildlife Service (Service), announce a 12-month finding for a petition to list the Bonneville cutthroat trout (Oncorhynchus clarki utah) as threatened throughout its range pursuant to the Endangered Species Act of 1973, as amended. After review of the best available scientific and commercial information, we find that listing the Bonneville cutthroat trout (BCT) is not warranted at this time.

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The finding announced in this document was made on September 28, 2001.


Data, information, comments, or questions regarding this notice should be sent to the Field Supervisor, U.S. Fish and Wildlife Service, Utah Ecological Services Field Office, 145 East 1300 South, Suite 404, Salt Lake City, Utah 84115. The complete administrative file for this finding is available for inspection during normal business hours, by appointment, at the above address. The status review document for the Bonneville cutthroat trout also may be obtained at that address, or at our Internet web site at <​cutthroat>.

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Yvette Converse at the above address or telephone (801) 524-5001, extension 135, or e-mail

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Section 4(b)(3)(B) of the Endangered Species Act of 1973, as amended (Act) (16 U.S.C. 1531 et seq.), requires that within 90 days of receipt of the petition, to the maximum extent practicable, we make a finding on whether a petition to list, delist, or reclassify a species presents substantial scientific or commercial information indicating that the requested action may be warranted. If there is substantial information, the Act requires that we review the status of the species and publish another finding, the 12-month finding, indicating whether the petitioned action is—(a) not warranted, (b) warranted, or (c) warranted but precluded from immediate listing proposal by other pending proposals of higher priority. Such 12-month findings are to be published promptly in the Federal Register.

In the mid-to late 1970s, professional fisheries organizations became concerned by reports from the professional and academic communities that few genetically “pure” populations of BCT remained in existence (Tanner 1936; Cope 1955; Sigler and Miller 1963, Holden et al. 1974, Behnke 1976, Hickman 1978). These reports prompted fish conservation groups to investigate the status of BCT. After receiving a petition from the Desert Fishes Council and American Fisheries Society to list BCT in 1979, we conducted a status review of the subspecies (U.S. Fish and Wildlife Service 1984). We determined at that time that listing the BCT was “warranted but precluded” by other higher priority activities (January 20, 1984; 49 FR 2485).

In 1992, we were again petitioned by the Desert Fishes Council and the Utah Wilderness Alliance to list BCT as threatened. We classified this as a “second petition” because it provided no new information, and listing the subspecies had already been determined to be “warranted but precluded.”

On February 26, 1998, we received a petition, dated February 5, 1998, from the Biodiversity Legal Foundation requesting that BCT be listed as threatened in those United States river and lake ecosystems where it presently exists, and to designate its occupied habitat as critical habitat within a reasonable period of time following the listing.

The petitioners assert that the remaining genetically pure stocks of BCT occur almost exclusively in small, isolated streams in mountainous areas, and that it is common for today's BCT stocks to have some degree of hybridization with introduced, nonnative trout.

The petitioners further assert that the BCT should be listed as threatened because the subspecies' present distribution and abundance are substantially reduced from historic conditions; remaining stocks are small, widely separated, and continue to decline in abundance; and the threats to the survival of BCT are pervasive and ongoing. The petitioners allege that threats to BCT include habitat destruction from logging and associated road building; adverse effects on habitat resulting from livestock grazing, mining, urban development, agricultural practices, and the operation of dams; historic and ongoing stocking of nonnative fish species that compete with or prey upon BCT; and excessive harvest by anglers.

The petitioners also are of the opinion that programs to protect and restore BCT are inadequate or nonexistent, and that stocks of this fish continue to be threatened by a wide variety of ongoing and proposed activities.

Status Review

On December 8, 1998, we published a 90-day finding for the BCT petition in the Federal Register (63 FR 67640). We found that the petition presented substantial information indicating that listing this subspecies may be warranted. At that time we initiated a review of the species' status within its historic range.

The comment period for submission of additional information originally expired on January 7, 1999. However, this comment period was reopened on January 13, 1999 (64 FR 2167), and extended to February 12, 1999. Numerous comments were received, evaluated, and incorporated, where appropriate, into this review. As this status review was being compiled, information was updated and reviewed to ensure that the review reflects the most accurate information available.

Geographic Range of Bonneville Cutthroat Trout

Since the desiccation of ancient Lake Bonneville nearly 10,000 years ago, the climate in the Bonneville Basin has remained relatively arid. Suitable conditions for cutthroat trout, such as adequate stream flow and water temperatures, range from higher elevations (approximately 8,000 to 11,000 feet above mean sea level) in small mountain streams and lakes within coniferous and deciduous forests and meadows to lower elevation (approximately 3,000 to 5,000 feet above mean sea level) alluvial desert river systems with sage-steppe grasslands and herbaceous riparian communities. For purposes of this status investigation, suitable BCT habitat within the subspecies' range is logically broken into five natural geographically and hydrologically distinct areas, henceforth referred to as Geographic Units (GU). The GUs are described in detail in the status review document available from Utah Ecological Services Field Office (see ADDRESSES). These GUs are generally categorized as—

(a) Bear Lake—includes Bear Lake and several small streams draining into Bear Lake within Idaho and Utah;

(b) Bear River—includes the upper Bear River draining the northwestern portion of the Uinta Mountains, the Smith's Fork and Thomas Fork watershed, the Cub River watershed, the Logan and Little Bear Rivers watershed, and others;

(c) Northern Bonneville—includes the Weber, Ogden, and Jordan Rivers (Great Salt Lake) watershed and the Provo and Spanish Fork Rivers (Utah Lake) watersheds;

(d) Western Bonneville—includes small streams draining both the east and west slopes of the Deep Creek Mountain range on the border of Utah and Nevada as well as Wheeler Peak (Great Basin National Park) and Mt. Mariah Wilderness Area (Humboldt-Toiyabe National Forest) draining from the east slopes of the Snake Mountain range of southeastern Nevada, and Snake and Steptoe valleys; and

(e) Southern Bonneville—includes Mt. Dutton and the Tusher Mountains and other drainages of the Sevier and Beaver River and northwestern portions Start Printed Page 51364of the Virgin River draining from the Pine Valley Mountains north of St. George, Utah.


Although some threats to BCT still occur, information reviewed in this status report indicates that the overall level of threats to the long-term persistence of BCT has decreased during the past 50 years. The majority of activities that caused the severe decline in BCT throughout its range appear to have occurred from 1850 to 1950. These activities included water development, commercial fish harvest, timber harvest, livestock grazing, urban development, and introduction of nonnative salmonids. Although most of these activities occur to some extent in different regions of the Bonneville Basin, there is no longer the same level of devastating impacts on BCT and its habitat that resulted in the wide-spread habitat destruction and BCT population decline of the late 1800s and early 1900s.


Habitat degradation from multiple sources is a considerable threat to BCT populations in some areas. Livestock grazing has been specifically identified as one primary reason for habitat degradation. Improper livestock grazing has led to moderate to severe localized impacts on stream habitat and riparian areas. Indirectly, excessive fine sediment, resulting from poor upland watershed condition, affects water quality and instream habitat. More direct damage includes decreased bank stability and loss or destruction of riparian area.

Road building can be a problem exacerbating sedimentation, bank instability, and loss of riparian area. Habitat damage from historic timber harvest has affected the long-term channel stability, substrate, and morphology in some streams, particularly in the mountainous areas where large timber stands were historically harvested for railroad and development.

Water development (diversions and dams) has irreversibly changed individual stream processes and hydrologic conditions in some drainages. Instream water diversion structures that dewater stream reaches, dams that impound water, and culverts that act as barriers to fish movement fragment or reduce available habitat and stream miles occupied for BCT. Throughout the deserts of the Bonneville Basin, humans compete with native wildlife for water. The overall impact of water development projects on BCT is nearly impossible to determine, but has no doubt been a large factor in the decline of native fish populations.

Although some streams receive extensive recreational traffic (including hikers, anglers, camping, horseback riding, and ATVs) which can result in instream and riparian damage or indirect effects to water quality and hydrology where the activity is not adequately controlled, impacts from these activities tend to be localized and do not affect overall watershed conditions.

Although some higher-profile areas are governed by extensive land-use regulation administered by the Federal land management agencies, cumulative habitat impacts from different land-use activities remain a concern for BCT populations in high-traffic areas.


Regulations in place to control fish harvest, fish stocking, and land-use incorporate an emphasis on the long-term persistence of BCT. Although considered a significant reason for the initial decline of BCT, fish harvest is no longer considered a threat to the long-term persistence of BCT.


Whirling disease is caused by Myxobolus cerebralis, a metazoan parasite that penetrates head and spinal cartilage of young-of-year salmonids. Once into the cartilage, the parasite multiplies quickly, affecting equilibrium of the fish. This can cause the fish to swim erratically or to have difficulty feeding or avoiding predators. Whirling disease was introduced into North America in the late 1950s and has damaged primarily wild rainbow trout (RBT) populations where the parasite becomes established. Although other salmonids also may be infected, the extent of disease manifested in other salmonids has not been fully assessed.

The life cycle of the parasite involves a robust spore that withstands freezing and desiccation. In addition, the spore persists for years or even decades and, therefore, is very difficult to eradicate from water systems. When ingested by a tiny common aquatic worm, Tubifex tubifex, the parasite transforms into its more fragile state that must infect young fish within several days or it will die (Whirling Disease Foundation 2000).

Within the range of BCT, whirling disease has been confirmed in several major water systems. However, to date there have been no documented population declines of BCT attributable to whirling disease. At this point, it is unclear if such a decline will happen. Based on results of studies summarized in the 6th Annual Whirling Disease Symposium and based on conversations with State fisheries managers and fish health experts in the Bonneville Basin, the following are some general notes pertaining to whirling disease in cutthroat trout (Granath 2000).

Spatial and temporal factors may play a role in the extent of damage to cutthroat populations from whirling disease. Timing of reproduction may influence extent of infection, if cutthroat larvae are hatched before or after the peak concentrations of the parasite. It has been further hypothesized that fluvial cutthroat trout may migrate to headwater reaches of streams to spawn, where hatched larvae may be either outside the range of contaminated reaches or amidst habitat conditions where the tubifex worms and spores may not or are less likely to accumulate in damaging or lethal concentrations. However, studies are preliminary and little can be predicted about the long-term impacts of whirling disease on cutthroat populations. One study suggests that cutthroat trout simply may develop less severe physiological disease compared to RBT.

Overall, recent research on whirling disease has uncovered substantial information now being used in management and control of the spread of this disease. Federal, State, and private sport-fishing interests have invested great effort and funds in finding a way to eradicate, control, or cure whirling disease. Although not necessarily intended for the conservation of native cutthroat trout, ongoing research undoubtedly benefits these native populations as managers seek to sustain and protect wild nonnative fisheries. In addition to research, fisheries health programs are focused on frequent and comprehensive testing of natural water systems and hatchery facilities to ensure early detection of the parasite. Strict regulations on fish culture, transport, and angling have been implemented. Also, public education programs on whirling disease and preventing its spread are widespread throughout angling communities.

Inadequate Regulatory Mechanisms

Stocking of RBT and other nonnative salmonids continues to be a potential threat. Although recent surveys and research indicate hybridization between BCT and other nonnative salmonids is not as prevalent as previously thought, the threat of hybridization remains in drainages where RBT are stocked in close proximity to pure BCT populations or where stocking of these Start Printed Page 51365species prevents reintroduction or colonization of BCT. Although most States are focusing on the issue and some State stocking protocols have been changed to prevent stocking of nonnative salmonids into BCT streams, the success of proposed and implemented changes to reduce the threats from hybridization, competition, and predation of nonnative salmonids on BCT has yet to be seen.

Many BCT populations are located on lands publicly owned and managed by the U.S. Forest Service (USFS), National Park Service (NPS), and Bureau of Land Management (BLM). Although some acute problems occur on lands managed by these agencies, public ownership provides some protection from development and guarantees public review of major activities which may adversely affect wildlife through compliance with the National Environmental Protection Act. In addition, some private citizens and local groups are getting involved in BCT conservation efforts in coordination with State and Federal agencies.

Numerous Federal and State regulatory mechanisms exist that, if properly administered and implemented, protect the long-term persistence of BCT and its habitat. However, this is dependent on the ability of those agencies to devote adequate resources toward fulfilling their responsibilities to environmental protection. Where regulations are not adequately enforced, BCT can be adversely impacted.

According to information collected for this review, the level of adequate Federal and State regulation varies among areas and among agencies, but generally has improved over the past 30 years. Although some problem areas still exist, the commitment from these agencies for the protection of environmental resources including BCT is greater than it has ever been. In addition, there is more collaboration between local communities, local governing entities, and State and Federal agencies, which allows more amicable resolution of land-use conflicts and better funding and commitment to conservation activities of BCT.

Other Natural or Manmade Factors Affecting its Continued Existence

In order to respond to the petitioners' concern regarding the threat of genetic introgression between BCT and other trout species, we investigated the standards used by the various management agencies to determine pure BCT stocks suitable for reclamation and conservation programs.

In the early 1900s, confusion regarding the physical description of pure BCT arose because of the extinction of BCT from the type locality in Utah Lake in the 1930s and subsequent confusing accounts. Early taxonomic distinctions were based solely on physical descriptions (Tanner and Hayes 1933; Behnke 1992). Reports of extinction from some well known locations and knowledge of widespread stocking of RBT and Yellowstone cutthroat trout (YCT) led some experts to speculate that BCT was extinct in its pure form (Tanner 1936; Cope 1955; Sigler and Miller 1963; Holden et al 1974). Such speculation became widely accepted because there were no accurate and accepted criteria to define pure BCT.

In assessing levels of hybridization among species or subspecies, known “pure” or unhybridized samples must be available. In the case of BCT, some of the earliest speculation and reports on purity were based on inter-drainage or inter-basin phenotypic differences before genetic technology was developed. However, this kind of information can be misleading where phenotypic differences do not reflect genetic differences or speciation. It was not until the 1960s and 1970s, when a few BCT populations were found in extremely isolated or pristine conditions where introductions of nonnative species had not occurred, which wildlife managers were certain they had identified pure BCT, that managers began to develop a standard for BCT purity (Behnke 1988; Hickman 1978). In the 1970s, criteria were developed by which purity could be assessed (Hickman 1978). Soon after, genetic technology was applied to the question of purity (Wydoski et al. 1976, Martin et al. 1985, Williams and Shiozawa 1989).

Two main issues developed related to purity of BCT. The first was how to discern purity. The second was what level of purity warrants protection. Criteria and protocols to address these two separate but related issues continued to evolve over the past three decades as technological advances and new information became available on what constitutes pure BCT (Wydoski et al. 1976, Martin et al. 1985, Williams and Shiozawa 1989, Shiozawa et al. 1993, Toline et al. 1999). With shifts in understanding of the importance of local genetic adaptions, it became important to identify a critical level or range of hybridization or a conservation criterion by which important populations could be identified and protected (Toline and Lentsch 1998, UDWR 2000). With such a criterion, managers hoped to ensure that important BCT genetic information was not dismissed or eradicated because of low levels of hybridization or speculative data.

In addition to genetic information, stocking records and biogeographic knowledge has been and continues to be used to assess the likelihood that a particular population is hybridized. It was originally suspected that where RBT or other cutthroat subspecies such as YCT were stocked, BCT were hybridized (Behnke and Zarn 1976, Sigler and Miller 1963; Holden et al 1974). However, with the development of recent techniques for genetic analysis, it has become apparent that many BCT populations have coexisted with RBT with extremely low or no levels of hybridization. In fact, recent genetic technology has proven invaluable in identifying pure populations previously suspected of hybridization (UDWR unpublished reports).

Overall, managers have used all of these techniques as well as other information to make the best judgement as to the purity of a given population and its distribution within a given system. In an effort to ensure a standard assessment of purity in how BCT is managed, the State wildlife agencies in Utah, Wyoming, Idaho, and Nevada have worked together to describe protocols and criteria for evaluating purity and managing BCT for conservation (UDWR 2000). This effort represents a combination of management strategies and input from academic and species experts to ensure that the process is based on the best available information and sound biology.

For the purposes of this status review, fish populations that State, Tribal, and Federal agency fisheries managers have designated as BCT, even though the precise genetic composition of each BCT population may not be completely described, are assumed to represent this subspecies unless specific physical, genetic, or behavioral information indicates otherwise.

Conservation Actions

The States of Utah, Wyoming, Idaho, and Nevada, USFS, BLM, NPS, Tribal governments, Trout Unlimited, and other involved parties reported numerous ongoing projects that are completed or being completed for the protection and restoration of BCT and their habitats. In addition, each State wildlife agency has in place conservation plans, conservation agreements, or other such interagency cooperative efforts to ensure the long-term persistence of BCT. A range-wide Conservation Agreement was recently Start Printed Page 51366finalized and includes all four State wildlife agencies as well as the Service, the USFS, BLM, Utah Reclamation Mitigation and Conservation Commission, and the NPS, with support from Trout Unlimited and other organizations. This agreement will improve coordination and effectiveness of conservation actions across State boundaries.

Specific conservation actions are planned, discussed, and described at semi-annual inter-agency meetings of BCT experts (agency and academic). Originally convened to review actions described under the Utah conservation agreement for BCT, these meetings have expanded to include Wyoming, Idaho, and Nevada State agencies as well as Federal agencies. Aquatic managers and BCT experts review upcoming plans for conservation actions and describe actions implemented in the past field season. In addition, native cutthroat trout management is discussed and the group provides a forum for developing standards on different issues such as assessing purity, chemical treatments for restoration, brood source development, inter- and intra-basin transfers, and stocking protocols.

These meetings are attended by all four State wildlife management agencies as well as the main Federal land management agencies, Trout Unlimited, local academic experts, and private citizens active in BCT conservation. Funds are allocated from different sources including State sportfishing monies, Federal Aid in Sportfishing monies, and USFS, Great Basin National Park, and other Federal land management agency funds, and are administered cooperatively among involved agencies. Coordination among agencies and groups and increased funding has led to substantial success in implementing conservation efforts in every GU. Specific conservation actions implemented within drainages and GUs are described in the Status Review for the species.

Overall, collaboration between local communities, local governing entities, and State and Federal agencies has increased substantially in comparison to past decades. This coordination allows more amicable resolution to land-use conflicts and better funding and commitment to conservation activities for BCT.


We have compiled and analyzed the most recent and best scientific and commercial data available on BCT to complete the status review. This information included published and unpublished reports, manuscripts, books and data, comments, memorandums, letters, phone communications, e-mail correspondence, and information gathered at meetings. In addition, persons who are considered species experts on BCT were provided the opportunity to comment on the data used in this report to ensure they were the most accurate and updated data available and that they were interpreted accurately.

Based on this analysis, the overall status of BCT has improved in every GU since the 1970s when researchers began to investigate the status of BCT for the purpose of its long-term conservation. Currently, BCT occupy a total of 1,372 kilometers (852 miles) of stream habitat and 28,352 hectares (70,059 acres) of lake habitat, with a total of 291 populations. It is possible additional BCT populations may be discovered in streams which have not been recently surveyed or explored. This potential is greatest in the Bear River and Northern GUs, which contain extensive natural water systems that remain uninvestigated. Viable, self-sustaining BCT populations occur within all five GUs. Almost every major drainage within the five GUs supports pure BCT populations, either remnant or reintroduced.

Although the numbers of extant BCT stocks are likely much lower than the historical number, they have increased by an order of magnitude or more in the past three decades. Based on information from early accounts of pioneer settlement and early descriptions of land-use and wildlife management, a noted decline in BCT populations occurred between 1850 and 1950. This decline was due to devastating impacts from land-use activities such as extensive water development, overharvest of fish through commercial industry, nonnative salmonid introductions, tie-hacking of timber, and improper livestock grazing. Although many of those threats have not been entirely eliminated, the devastating disregard for land and wildlife no longer occurs to the extent that it did between 1850 and 1950. In addition, most BCT populations are located on lands publicly owned and managed by the USFS, NPS, and BLM. Public ownership provides some element of protection from development and guarantees public review of major activities which may adversely affect wildlife through compliance with the National Environmental Policy Act and agency regulations.

The improved status of BCT in the past 30 years can be attributed to increased sampling effort, improved technology for identification of pure populations, population expansion efforts (transplants and brood source development) that have resulted in establishment of additional BCT populations, and improved habitat and flow conditions in some streams. Because current management plans are operational and describe BCT conservation activities for future decades, it is likely that additional BCT populations will be identified, additional reintroduced BCT populations will become established, and stream habitat and flow conditions will continue to be improved. Thus, the status of BCT will likely continue to improve as surveys are completed and conservation activities are completed.

Based on this analysis, as detailed in the status review document, the trajectory of BCT status within its native range is toward additional populations, reduced threats, and improved habitat conditions. Although some populations may be more impacted than others by future development, land-use, and stocking, there is currently no indication that BCT is in danger of extinction or likely to become so in the foreseeable future throughout all of its range or in any of the five GUs.

Therefore, listing of the BCT as a threatened or endangered species under the Act is not warranted at this time.

References Cited

A complete list of references cited in this notice is available from the Utah Ecological Services Field Office (see ADDRESSES).


The primary author of this document is Yvette Converse (see ADDRESSES).


The authority for this action is the Endangered Species Act (16 U.S.C. 1531 et seq.).

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Dated: September 28, 2001.

Marshall P. Jones, Jr.,

Acting Director, Fish and Wildlife Service.

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[FR Doc. 01-24805 Filed 10-5-01; 8:45 am]