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[Federal Register Volume 90, Number 124 (Tuesday, July 1, 2025)]
[Proposed Rules]
[Pages 28701-28715]
From the Federal Register Online via the Government Publishing Office []
[FR Doc No: 2025-12009]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2025-0033; FXES1111090FEDR-256-FF09E21000]
RIN 1018-BI18


Endangered and Threatened Wildlife and Plants; Endangered Species 
Status for Barrens Darter

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
list the Barrens darter (Etheostoma forbesi), a fish species from 
Cannon, Coffee, Grundy, and Warren Counties, Tennessee, as an 
endangered species under the Endangered Species Act of 1973, as amended 
(Act). This determination also serves as our 12-month finding on a 
petition to list the Barrens darter. After a review of the best 
scientific and commercial data available, we find that listing the 
species is warranted. Accordingly, we propose to list the Barrens 
darter as an endangered species under the Act. If we finalize this rule 
as proposed, it would add this species to the List of Endangered and 
Threatened Wildlife and extend the Act's protections to the species. We 
find that designating critical habitat for this species is not 
determinable at this time.

DATES: We will accept comments received or postmarked on or before 
September 2, 2025. Comments submitted electronically using the Federal 
eRulemaking Portal (see ADDRESSES, below) must be received by 11:59 
p.m. eastern time on the closing date. We must receive requests for a 
public hearing, in writing, at the address shown in FOR FURTHER 
INFORMATION CONTACT by August 15, 2025.

ADDRESSES: Comment submission: You may submit comments by one of the 
following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal: . In the Search box, enter FWS-R4-ES-2025-0033, 
which is the docket number for this rulemaking. Then, click on the 
Search button. On the resulting page, in the panel on the left side of 
the screen, under the Document Type heading, check the Proposed Rule 
box to locate this document. You may submit a comment by clicking on 
``Comment.''
    (2) By hard copy: Submit by U.S. mail to: Public Comments 
Processing, Attn: FWS-R4-ES-2025-0033, U.S. Fish and Wildlife Service, 
MS: PRB/3W, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
    We request that you send comments only by the methods described 
above. We will post all comments on . This 
generally means that we will post any personal information you provide 
us (see Information Requested, below, for more information).
    Availability of supporting materials: Supporting materials, such as 
the species status assessment report, are available on the Service's 
website at /office/tennessee-ecological-services, at 
 at Docket No. FWS-R4-ES-2025-0033, or both.

FOR FURTHER INFORMATION CONTACT: Daniel Elbert, Field Supervisor, U.S. 
Fish and Wildlife Service, Tennessee Ecological Services Field Office; 
telephone 931-431-2480; [email protected]. Individuals in the 
United States who are deaf, deafblind, hard of hearing, or have a 
speech disability may dial 711 (TTY, TDD, or TeleBraille) to access 
telecommunications relay services. Individuals outside the United 
States should use the relay services offered within their country to 
make international calls to the point-of-contact in the United States. 
Please see Docket No. FWS-R4-ES-2025-0033 on  for a document that summarizes this proposed rule.

SUPPLEMENTARY INFORMATION:

Information Requested

    We intend that any final action resulting from this proposed rule 
will be based on the best scientific and commercial data available and 
be as accurate and as effective as possible. Therefore, we request 
comments or information from other governmental agencies, Native 
American Tribes, the scientific community, industry, or any other 
interested parties concerning this proposed rule. We particularly seek 
comments concerning:
    (1) The species' biology, range, and population trends, including:
    (a) Biological or ecological requirements of the species, including 
habitat requirements for feeding, breeding, and sheltering;
    (b) Genetics and taxonomy;
    (c) Historical and current range, including distribution patterns 
and the locations of any additional populations of this species;
    (d) Historical and current population levels, and current and 
projected trends; and
    (e) Past and ongoing conservation measures for the species, its 
habitat, or both.
    (2) Threats and conservation actions affecting the species, 
including:
    (a) Factors that may be affecting the continued existence of the 
species, which may include habitat modification or destruction, 
overutilization, disease, predation, the inadequacy of existing 
regulatory mechanisms, or other natural or manmade factors;
    (b) Biological, commercial trade, or other relevant data concerning 
any threats (or lack thereof) to this species; and
    (c) Existing regulations or conservation actions that may be 
addressing threats to this species.
    (3) Additional information concerning the historical and current 
status of this species.
    Please include sufficient information with your submission (such as 
scientific journal articles or other publications) to allow us to 
verify any scientific or commercial information you include.
    Please note that submissions merely stating support for, or 
opposition to, the action under consideration without providing 
supporting information, although noted, do not provide substantial 
information necessary to support a determination, as section 4(b)(1)(A) 
of the Act directs that determinations as to whether any species is an 
endangered or a threatened species must be made solely on the basis of 
the best scientific and commercial data available, and section 4(b)(2) 
of the Act directs that the Secretary shall designate critical habitat 
on the basis of the best scientific data available.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in ADDRESSES. We request that you 
send comments only by the methods described in ADDRESSES.
    If you submit information via , your 
entire submission--including any personal identifying information--will 
be posted on the website. If your submission is made via a hardcopy 
that includes personal identifying information, you

[[Page 28702]]

may request at the top of your document that we withhold this 
information from public review. However, we cannot guarantee that we 
will be able to do so. We will post all hardcopy submissions on .
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on .
    Our final determination may differ from this proposal because we 
will consider all comments we receive during the comment period as well 
as any information that may become available after this proposal. Based 
on the new information we receive (and, if relevant, any comments on 
that new information), we may conclude that the species is threatened 
instead of endangered, or we may conclude that the species does not 
warrant listing as either an endangered species or a threatened 
species. In our final rule, we will clearly explain our rationale and 
the basis for our final decision, including why we made changes, if 
any, that differ from this proposal.

Public Hearing

    Section 4(b)(5) of the Act provides for a public hearing on this 
proposal, if requested. Requests must be received by the date specified 
in DATES. Such requests must be sent to the address shown in FOR 
FURTHER INFORMATION CONTACT. We will schedule a public hearing on this 
proposal, if requested, and announce the date, time, and place of the 
hearing, as well as how to obtain reasonable accommodations, in the 
Federal Register and local newspapers at least 15 days before the 
hearing. We may hold the public hearing in person or virtually via 
webinar. We will announce any public hearing on our website, in 
addition to the Federal Register. The use of virtual public hearings is 
consistent with our regulations at 50 CFR 424.16(c)(3).

Previous Federal Actions

    For a detailed description of Federal actions concerning the 
Barrens darter that occurred prior to April 2019, please refer to the 
12-month not-warranted finding we published in the Federal Register on 
April 4, 2019 (84 FR 13237).
    On September 27, 2022, the Center for Biological Diversity (CBD) 
filed a complaint challenging the merits of our 2019 12-month not-
warranted finding (Center for Biological Diversity v. Service, et al., 
No. 1:22-cv-02922 (D.D.C.)). Subsequently, the CBD and Service entered 
into a stipulated settlement agreement whereby both parties agreed the 
Service would submit to the Office of the Federal Register for 
publication a new 12-month finding for the Barrens darter by June 30, 
2025. By publishing this proposed rule, which constitutes our 12-month 
finding and proposes to list the Barrens darter as an endangered 
species under the Act, the Service is complying with the settlement 
agreement.

Peer Review

    To inform the new 12-month finding stipulated by the settlement 
agreement, a species status assessment (SSA) team prepared, updated, 
and revised the Barrens darter SSA report (Service 2025, entire). The 
SSA team was composed of Service biologists, in consultation with other 
species experts. The SSA report (version 3.0: Service 2025, entire) 
represents a compilation of the best scientific and commercial data 
available concerning the status of the species, including new 
scientific information that has become available since our initial SSA 
report (version 1.0: Service 2018, entire); the SSA report also 
includes the impacts of past, present, and future factors (both 
negative and beneficial) affecting the species.
    In accordance with our joint policy on peer review published in the 
Federal Register on July 1, 1994 (59 FR 34270), and our August 22, 
2016, memorandum updating and clarifying the role of peer review in 
listing and recovery actions under the Act (/sites/default/files/documents/peer-review-policy-directors-memo-2016-08-22.pdf), we will solicit the independent scientific review of the 
Barrens darter SSA report (Service 2025, entire) from at least three 
appropriate specialists. The SSA report will be made available for peer 
and partner review concurrently with this proposed listing rule. We 
will address and incorporate the results of the peer reviews, as 
appropriate, into the updated SSA report and the final decision 
document.

I. Proposed Listing Determination

Background

    A thorough review of the taxonomy, life history, and ecology of the 
Barrens darter is presented in the SSA report (version 3.0; Service 
2025, pp. 5-9).
    The Barrens darter is a small fish endemic to streams in the 
Barrens Plateau region of middle Tennessee. It is found in the Collins 
River watershed, which is a tributary to the Caney Fork of the 
Cumberland River drainage (see figure 1, below). The Barrens darter 
belongs to the Stigmacerca clade (lineage of species that includes a 
common ancestor and its descendants), with all 11 member species 
sharing the distinguishing characteristic of a vertical row of three 
black dots at the base of the tail fin. Per the formal species 
description that is part of a larger review of closely related species 
(Page et al. 1992, entire), females and non-breeding males in the clade 
have a pattern of brown mottling on a light tan background, 9 to 13 
small blotches along the sides, and 6 to 8 dark brown saddles on the 
back. In breeding male Barrens darters, the second dorsal fin is black 
with a yellow-gold margin that is lightly speckled with black.
    Barrens darters occur almost exclusively in small headwater streams 
with slab rock substrates and strong groundwater influence. They likely 
prey on larval aquatic insects and microcrustaceans, as has been 
observed for other species in Stigmacerca. Spawning occurs between mid-
March and early June. During spawning, the male establishes a territory 
around a cavity under a slab rock and, based on its body size and 
quality of its nest cavity, attracts females. Males also produce sounds 
to court females and defend the nest cavity from other males. Once a 
female has chosen to spawn with a male, the pair invert under the rock 
and the female adheres eggs to the underside of the rock in a single 
layer. Multiple females will lay eggs in a single nest, with average 
count per nest of 457 eggs and a maximum count of 1,992 eggs observed 
in one study (Bergen et al. 2012, p. 235). The male cleans the eggs and 
guards them from predators until they hatch, in about 15.5 days on 
average. After hatching larvae quickly drop toward the stream bottom, 
remaining among the substrates near the nest rock. In the closely 
related spottail darter (Etheostoma squamiceps), the transition from 
the relatively non-mobile larval stage to the more mobile juvenile 
stage was complete at approximately 2 months (Page 1974, pp. 11-12). 
Time from larva to juvenile is likely similar in the Barrens darter. 
Barrens darters reach adulthood (sexual maturity) between one to two 
years post-hatching, have an approximate lifespan of 3 years, and may 
rarely live to 4 years of age.
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    We assessed the viability of the Barrens darter in our initial SSA 
report (Service 2018, entire), which informed our 2019 not-warranted 
12-month finding (84 FR 13237; April 4, 2019). Concurrent with 
development of the initial SSA report, ichthyologists had initiated a 
Barrens darter distribution and population genetics survey. The 
analysis of the survey was published in a peer-reviewed journal and 
mapped the expansion of native fringed darters (Etheostoma 
crossopterum) upstream, in some cases into headwater streams occupied 
by Barrens darters where fringed darters completely replaced Barrens 
darters, through competition and hybridization (see Summary of 
Biological Status and Threats, below), over time (Harrington et al. 
2020, entire). The information provided in Harrington et al. (2020) 
highlighted the immediacy of the threat posed by the fringed darter, 
which was not well understood when we produced our 2018 SSA report. It 
also documented the current rangewide distribution of the Barrens 
darter, detecting extirpations and adding occurrence records in 
previously undocumented sites. As discussed in this proposed rule, we 
compiled and used the best scientific information currently available, 
including the data provided in Harrington et al. (2020) to update our 
SSA (Service 2025, entire) and subsequent 12-month finding and status 
determination.

Regulatory and Analytical Framework

Regulatory Framework

    Section 4 of the Act (16 U.S.C. 1533) and the implementing 
regulations in title 50 of the Code of Federal Regulations set forth 
the procedures for determining whether a species is an endangered 
species or a threatened species, issuing protective regulations for 
threatened species, and designating critical habitat for endangered and 
threatened species.
    The Act defines an ``endangered species'' as a species that is in 
danger of extinction throughout all or a significant portion of its 
range and a ``threatened species'' as a species that is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. The Act requires that we 
determine whether any species is an endangered species or a threatened 
species because of any of the following factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;

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    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    These factors represent broad categories of natural or human-caused 
actions or conditions that could have an effect on a species' continued 
existence. In evaluating these actions and conditions, we look for 
those that may have a negative effect on individuals of the species, as 
well as other actions or conditions that may ameliorate any negative 
effects or may have positive effects.
    We use the term ``threat'' to refer in general to actions or 
conditions that are known to or are reasonably likely to negatively 
affect individuals of a species. The term ``threat'' includes actions 
or conditions that have a direct impact on individuals (direct 
impacts), as well as those that affect individuals through alteration 
of their habitat or required resources (stressors). The term ``threat'' 
may encompass--either together or separately--the source of the action 
or condition or the action or condition itself.
    However, the mere identification of any threat(s) does not 
necessarily mean that the species meets the statutory definition of an 
``endangered species'' or a ``threatened species.'' In determining 
whether a species meets either definition, we must evaluate all 
identified threats by considering the species' expected response and 
the effects of the threats--in light of those actions and conditions 
that will ameliorate the threats--on an individual, population, and 
species level. We evaluate each threat and its expected effects on the 
species, then analyze the cumulative effect of all of the threats on 
the species as a whole. We also consider the cumulative effect of the 
threats in light of those actions and conditions that will have 
positive effects on the species, such as any existing regulatory 
mechanisms or conservation efforts. The Secretary determines whether 
the species meets the definition of an ``endangered species'' or a 
``threatened species'' only after conducting this cumulative analysis 
and describing the expected effect on the species.
    The Act does not define the term ``foreseeable future,'' which 
appears in the statutory definition of ``threatened species.'' Our 
implementing regulations at 50 CFR 424.11(d) set forth a framework for 
evaluating the foreseeable future on a case-by-case basis which is 
further described in the 2009 Memorandum Opinion on the foreseeable 
future from the Department of the Interior, Office of the Solicitor (M-
37021, January 16, 2009; ``M-Opinion,'' available online at ). 
We need not identify the foreseeable future in terms of a specific 
period of time. We will describe the foreseeable future on a case-by-
case basis, using the best available data and taking into account 
considerations such as the species' life-history characteristics, 
threat projection timeframes, and environmental variability.

Analytical Framework

    The SSA report documents the results of our comprehensive 
biological review of the best scientific and commercial data available 
regarding the status of the species, including an assessment of the 
potential threats to the species. The SSA report does not represent our 
decision on whether the species should be proposed for listing as an 
endangered or threatened species under the Act. However, it does 
provide the scientific basis that informs our regulatory decisions, 
which involve the further application of standards within the Act and 
its implementing regulations and policies.
    To assess the viability of the Barrens darter, we used the three 
conservation biology principles of resiliency, redundancy, and 
representation (Shaffer and Stein 2000, pp. 306-310). Briefly, 
resiliency is the ability of the species to withstand environmental and 
demographic stochasticity (for example, wet or dry, warm or cold 
years); redundancy is the ability of the species to withstand 
catastrophic events (for example, droughts, large pollution events); 
and representation is the ability of the species to adapt to both near-
term and long-term changes in its physical and biological environment 
(for example, climate conditions, pathogens). In general, species 
viability will increase with increases in resiliency, redundancy, and 
representation (Smith et al. 2018, p. 306). Using these principles, we 
identified the species' ecological requirements for survival and 
reproduction at the individual, population, and species levels, and 
described the beneficial and risk factors influencing the species' 
viability.
    The SSA process can be categorized into three sequential stages. 
During the first stage, we evaluated the individual species' life-
history needs. The next stage involved an assessment of the historical 
and current condition of the species' demographics and habitat 
characteristics, including an explanation of how the species arrived at 
its current condition. The final stage of the SSA involved making 
predictions about the species' responses to positive and negative 
environmental and anthropogenic influences. Throughout all of these 
stages, we used the best scientific and commercial data available to 
characterize viability as the ability of a species to sustain 
populations in the wild over time, which we then used to inform our 
regulatory decision.
    The following is a summary of the key results and conclusions from 
the SSA report; the full SSA report can be found at Docket No. FWS-R4-
ES-2025-0033 on .

Summary of Biological Status and Threats

    In this discussion, we review the biological condition of the 
species and its resources, and the threats that influence the species' 
current and future condition, in order to assess the species' overall 
viability and the risks to that viability.

Species Needs

    To maintain viability at the individual level and species level, 
Barrens darters need third-order (method in Strahler 1957, p. 914) or 
smaller headwater streams (Zuber 2014, p. 46), as they are not 
generally found in larger streams. Areas with intact, rather than 
eroded, stream banks are another important habitat feature that support 
Barrens darters (Zuber 2014, p. 47). Intact stream banks harbor 
vegetation that provides shade that moderates water temperatures, and 
these banks ensure rocks used for shelter and spawning are not covered 
by excessive sediments. Barrens darters have been observed mostly in 
streams with moderate pH (average 7.3, but in one case, as high 9.0), 
and relatively low total dissolved solids (less than 135 parts per 
million) (Zuber 2014, p. 45), indicating these values are reasonable 
parameters for viability. Observations during the March to June 
spawning season indicated important habitat features for individuals, 
including flat rocks for nesting, relatively low water depth (40 
centimeters (15.7 inches) or less), and water temperatures ranging from 
6 to 23 degrees Celsius (43 to 73 degrees Fahrenheit) (Bergen et al. 
2012, pp. 436-437). As discussed below (see Threats), fringed darters 
are a threat to Barrens darter persistence. Therefore, Barrens darters 
need sites that are free of fringed darters.
    At the species level, the Barrens darter needs connected 
populations distributed across multiple streams and watersheds. The 
Barrens darter also needs sufficient resources (food, space,

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refugia, etc.) to sustain enough individuals so that populations can 
withstand normal demographic and environmental stochasticity 
(resiliency). In addition, dispersion of populations within multiple 
streams and watersheds (redundancy) reduces the likelihood of rangewide 
impacts from catastrophic events, such as an extreme drought or flood 
that kills individuals or causes them to move to unsuitable habitats, 
or invasion of a species that competes for spawning and feeding 
resources. Long-term viability will require multiple resilient 
populations to persist into the future; for the Barrens darter, this 
means good habitat (resiliency) to support multiple populations in 
close enough proximity and with sufficient connectivity to allow for 
emigration/immigration (redundancy). Sufficient connectivity will also 
support maintenance of genetic diversity and adaptive capacity 
(representation).

Threats

    The greatest threat to the Barrens darter is competition and 
hybridization with the fringed darter, which has expanded its range in 
the Collins River drainage over the past several decades (Harrington et 
al. 2020, entire). The spatial pattern of fringed darter incursion into 
and near streams occupied by Barrens darters was not fully assessed and 
mapped until 2020 (Harrington et al. 2020, entire). Due to temporal and 
spatial gaps in fish surveys in the Collins River system, the intensity 
of the fringed darter invasion remained unclear prior to the new 
Barrens darter and fringed darter distribution records reported in 
2020. Additionally, the taxonomic identity of several collected 
specimens held in museum collections was uncertain prior to 2020. This 
uncertainty was resolved as the museum specimens that were not 
confidently identified as Barrens darter, fringed darter, or hybrids 
were verified genetically or morphologically in the study reported in 
2020. In summary and as reported in Harrington et al. (2020, entire), 
compiling all historical distribution data, resurveying historical 
sites and surveying new sites, and verifying the taxonomic identity of 
female specimens and hybrids using genetics and morphology provided the 
most comprehensive information to date on the changes in the 
distribution of the two species in the Collins River system. This 
information clearly showed the broad expansion of the fringed darter 
into or close to streams occupied by Barrens darters. Because fringed 
darters hybridize and compete with Barrens darters for nesting space 
(see ``Fringed Darter Threat of Native Invasion'', below), the ongoing 
expansion of fringed darters into Barrens darter habitat is the 
greatest threat to the Barrens darter. This threat was not fully 
understood or incorporated in the 2019 status determination (84 FR 
13237), which was informed by a Species Status Assessment completed in 
2018 (Service 2018, entire); however, the imminence and magnitude of 
this threat is now fully recognized and used to inform this 
determination.
    Other major threats influencing the viability of the Barrens darter 
are habitat loss from degradation of stream banks, loss of instream 
cover, degradation of water quality, and habitat fragmentation and 
isolation. When these threats are combined with effects from the 
invasion of the fringed darter, they act synergistically to negatively 
impact Barrens darter populations. The habitat-related threats stem 
from agricultural activities and associated riparian clearing that 
alters instream habitat and hydrology needed by the Barrens darter. In 
addition to row crops and grazing, agriculture on the Barrens Plateau 
includes several plant nurseries, which require water withdrawals that 
may reduce flows in headwater streams and exacerbate the effects of 
drought.
Fringed Darter Threat of Native Invasion
    The fringed darter has a large native range, occurring in the 
middle and lower Cumberland River system, middle and lower Tennessee 
River system, and two Mississippi River tributaries. Fringed darters 
occupy a broader range of stream sizes than Barrens darters, and based 
on historical records, fringed darters likely occurred in tributaries 
to the lower Collins River system (see figure 2, below). One fringed 
darter specimen voucher (University of Tennessee Etnier Ichthyological 
Collection, UT 91.646) was collected in the mainstem of Barren Fork, in 
McMinnville, in 1972. Records from 1994 show several sites with fringed 
darter occurrences in Mountain Creek (where Barrens darters are not 
known to have occurred), which is the lower-most tributary to the 
Collins River, and in tributaries of the Caney Fork, downstream from 
the mouth of the Collins River (Madison 1995, p. 78). Further, fringed 
darters likely are native to the lower Collins River system as 
indicated by the presence of a mitochondrial DNA haplotype found in the 
Upper Caney River and Collins River systems that is not found elsewhere 
in the Cumberland River system (Harrington et al. 2020, p. 6).
    Over the past 40 to 50 years, fringed darters have expanded their 
range into the upper reaches of the Collins River system, which may be 
due to a phenomenon called native invasion (Scott and Helfman 2001, pp. 
9-11). This occurs when changes to the landscape make habitats in 
headwater streams resemble those in medium and larger streams, creating 
favorable conditions for invasion by species that naturally occur and 
once were limited to downstream habitats. Fringed darters have replaced 
Barrens darters in the West Fork Hickory Creek system, where Barrens 
darters were extirpated sometime between 1983 and 2001, and in Mud 
Creek (Barren Fork system), where Barrens darters were extirpated 
sometime between 2009 and 2018 (Harrington et al. 2020, p. 4; see 
figure 2, below). Both creek systems are impaired by alteration of 
streamside vegetation, and West Fork Hickory Creek is also impaired by 
E. coli and nutrients (Tennessee 2024 List of Impaired and Threatened 
Waters), suggesting native invasion as a factor in the extirpations.
    Data collected to date suggest gene flow from Barrens darters into 
fringed darter populations, and possible bias of female Barrens darters 
hybridizing with male fringed darters, which is the larger of the two 
species (Service 2018, p. 15; Harrington et al. 2020, pp. 17-19). Of 
364 Collins River system fringed darters examined, 4 specimens from the 
West Fork Hickory Creek system and 8 specimens from the Mud Creek and 
McAfee Creeks in the South Fork Barren system were found to have 
Barrens darter mitochondrial DNA and fringed darter nuclear DNA 
(Harrington et al. 2020, pp. 14-15). Mitochondrial DNA is inherited 
only from the mother in most species, including fishes. Therefore, the 
occurrence of Barrens darter DNA in fringed darters (based on 
morphology) may point to female Barrens darters preferentially 
selecting the larger male fringed darters to breed with when the 
species co-occur or that fringed darters are more successful in 
competing for spawning cavities. Because female Barrens darters must 
mate in spawning cavities, male fringed darters successfully competing 
for the spawning cavities results in female Barrens darters mating with 
male fringed darters rather than with male Barrens darters.
    Fringed darters are a substantial threat to Barrens darters by 
competing for spawning space and mates, and likely for other resources 
including prey and cover. After fringed darters colonize a Barrens 
darter site, the Barrens darter population is at high risk of becoming 
replaced over time, as some of the Barrens darters lose their genetic 
identity through hybridization. The

[[Page 28706]]

male Barrens darters, due to competition for mates and spawning 
cavities or female preference for fringed darters, may fail to produce 
offspring at sufficient rates to sustain future generations. Because 
Barrens darters have a short 3-year lifespan, most males survive long 
enough to attempt spawning in two seasons per lifetime. Thus, if only a 
few male Barrens darters successfully produce annually due to 
competition with fringed darters, the pace of replacing generations 
will be insufficient, quickly driving the Barrens darter population to 
extirpation.
    Except for the upper Collins River, fringed darters have advanced 
relatively rapidly into the headwater habitats that Barrens darters 
need for survival. Habitat degradation present in many stream reaches 
of the Collins River system is a major threat to Barrens darters 
because, in addition to its direct effect of lost cover, it promotes 
invasion of fringed darters into the headwaters. Where Barrens darters 
and fringed darters have been observed to co-occur, Barrens darters 
became extirpated within 15 years. Therefore, due to competition, 
hybridization, and their ongoing expansion in the Collins River system, 
which comprises the entirety of the range of the Barrens darter, 
fringed darters pose the greatest threat to the viability of the 
Barrens darter.
    Although fish survey records prior to the 1980s are sparse, it 
appears that the Barrens darter's decline did not start (or the decline 
was not noticed) until fringed darters began moving into the Barrens 
darter's headwater habitat. Because Barrens darters withstood habitat 
and water quality disturbances for a long period prior to the fringed 
darter invasions, including times prior to the CWA or when the CWA 
regulations were first being implemented, it is more likely that the 
invasions together with habitat and water quality impacts, rather than 
habitat and water quality impacts alone, are a crucial driver of 
Barrens darter declines. In summary, competition and hybridization with 
the fringed darter is occurring in two of the three systems that 
comprise the Barren darter's range and is highly likely to continue.
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Habitat Threats From Agricultural Activities and Riparian Clearing
    Land cover and land use have a strong influence on the quality and 
quantity of water in streams (Allan 2004, entire; Freeman and Marcinek 
2006, entire). Vegetation coverage and type can affect the timing, 
amount, temperature, and quality of water in streams, and livestock 
with free access to stream channels and streambanks can have direct and 
indirect effects on water quality through waste and sedimentation. The 
Barrens Plateau area of Tennessee is very susceptible to impacts from 
agriculture according to the Tennessee State Wildlife Action Plan 
(Tennessee Wildlife Resources Agency (TWRA) 2015, p. 23).
    Many of the streams within the Barrens darter's range are used as 
water sources for cattle and other livestock. Reduced riparian 
vegetation on lands where livestock have access to streams and where 
vegetation is destroyed by livestock or fencing is absent or 
insufficiently maintained can lead to increased water temperatures due 
to loss of shade. Elevated temperatures may reduce Barrens darter nest 
success

[[Page 28708]]

by reducing the number of eggs produced, hatching rates, or larval 
survival, as was observed in a laboratory study of temperature effects 
on the fountain darter (Etheostoma fonticola) (Bonner et al 1998 p. 
974). Unfettered cattle access increases bank erosion, which is 
negatively associated with Barrens darter occurrence (Zuber 2014, p. 
95), and unfettered cattle access increases turbidity and sedimentation 
in streams. Sedimentation from livestock and other sources has the 
potential to cover cobble and other instream substrates, resulting in 
lower habitat quality, fewer food items, and fewer spawning cavities. 
In addition, influxes of large amounts of animal waste increase the 
amount of nutrients in streams and further reduce visibility, which can 
impact the spawning displays of Barrens darters. Increased bacterial 
levels, associated with nutrification, may increase the risk of 
infection to eggs, reducing egg viability (Pat Rakes, Conservation 
Fisheries, Inc. 2018, pers. comm.). Fungus-covered eggs in Barrens 
darter nests have been observed in Lewis Creek and Duke Creek in the 
Barren Fork system (Hansen et al. 2006, p. 66; Bergen et al. 2012, p. 
438).
    Several streams currently occupied by the Barrens darter have 
impaired water, impaired habitat quality, or both (Tennessee 2024 List 
of Impaired and Threatened Waters, not paginated). Charles Creek, a 
direct tributary to the lower Collins River, is impaired by Escherichia 
coli (E. coli) along its entire length, but the State reports the 
source of the E. coli is unknown. Liberty Creek, in the Barren Fork 
system, is impaired by alteration of stream-side vegetation and cover 
due to crop production and grazing in the riparian area. Two 
tributaries to the Upper Collins River, Savage Cove Creek and Taylor 
Creek, are listed by the State as impaired. Savage Cove Creek is 
impaired by alteration of streamside vegetative cover due to specialty 
crop production (nurseries) and grazing in the riparian area. Taylor 
Creek is impaired by alteration of streamside vegetative cover, low 
dissolved oxygen, and sedimentation due to nurseries and silviculture 
activities. In summary, all three MUs currently occupied by the Barrens 
darter contain streams listed by the State as impaired and 4 of the 8 
streams occupied by the species are experiencing impaired water or 
habitat quality, or both, and that impairment is expected to continue.
Effects of Drought
    Barrens darter habitat can be diminished during droughts, and some 
streams in the Collins River system have occasionally dried out 
completely during periods of moderate drought (Harrington et al. 2020, 
p. 19). Flow in Duke Creek and Lewis Creek in the Barren Fork system 
ceased during parts of May and June 2009, coinciding with the species' 
spawning period, when the streams were reduced to stretches of isolated 
pools (Bergen et al. 2012, p. 237). As a headwater species, Barrens 
darters are likely adapted and resilient to occasional intermittent 
reduced flows or streambed drying. During moderate droughts, unless 
there is strong groundwater influence, the pattern of drying typically 
starts near the head of the stream channel and progresses downstream, 
and Barrens darters have adapted to this headwater flow dynamic. 
However, periods of drought require movement, usually downstream, to 
access wetted stream channels. Currently, the suitability of these 
downstream areas as drought refugia is diminished because they have 
impaired habitat quality, are occupied by fringed darters, or both (see 
``Fringed Darter Threat of Native Invasion,'' above).
Conservation Efforts and Regulatory Mechanisms
    Application of best management practices (BMPs), such as fencing 
livestock away from streambanks and riparian areas, providing 
alternative watering sources, and maintaining or planting riparian 
buffers with native vegetation, can positively affect the viability of 
the Barrens darter. However, outside of the few surveys and life-
history studies that informed our SSA report, there have not been any 
targeted conservation efforts for the Barrens darter. This species 
occurs in streams located entirely on private land and does not receive 
the benefits of public conservation land. Efforts have been made to 
fence livestock out of streams and provide them alternate water sources 
in some places where Barrens darters occur. These are very limited in 
scale and amount of overlap with the Barrens darter's range. Most of 
these efforts have been funded and organized through Partners for Fish 
and Wildlife agreements with landowners, but most of the agreements 
have expired, so it is unclear whether riparian buffer maintenance is 
continuing at sites where the agreements were applied.
    The Barrens darter is afforded some protection via State and 
Federal regulatory mechanisms. It is listed as endangered by the State 
of Tennessee (TWRA 2024, p. 2), making it unlawful to take the Barrens 
darter without a State permit. Additionally, the bluemask darter 
(Etheostoma akatulo) is federally listed as an endangered species under 
the Act, and the Barrens darter currently benefits from the Act's 
protections where these species' ranges overlap along approximately 2.3 
mi (3.7 km) of the upper Collins River. The Clean Water Act of 1977 
(CWA; 33 U.S.C. 1251 et seq.), as amended, which is implemented by 
Tennessee Department of Environmental Conservation through Tennessee's 
Water Quality Control Act of 1977 and its implementing State 
regulations, provides a level of protection to Barrens darter habitat 
and water quality. While the protections afforded by these regulatory 
mechanisms have not fully prevented the degradation of some habitats 
used by the Barrens darter, as some streams occupied by the Barrens 
darter are recognized as having impaired water and habitat quality, the 
species has benefited from improvements in water quality and habitat 
conditions stemming from these mechanisms. For example, CWA section 319 
grants for States to address nonpoint source runoff or CWA section 402 
permits to reduce pollutants in point source discharges to levels that 
are protective of aquatic life have served to reduce impacts to 
Tennessee streams from effluents, runoff, and landscape disturbance.

Cumulative Effects

    We note that, by using the SSA framework to guide our analysis of 
the scientific information documented in the SSA report (Service 2025, 
entire), we have analyzed the cumulative effects of identified threats 
and conservation actions on the species. To assess the current and 
future condition of the species, we evaluate the effects of all the 
relevant factors that may be influencing the species, including threats 
and conservation efforts. Because the SSA framework considers not just 
the presence of the factors, but to what degree they collectively 
influence risk to the entire species, our assessment integrates the 
cumulative effects of the factors and replaces a standalone cumulative-
effects analysis.

Current Condition

    Historically, the Barrens darter occurred in four watersheds in the 
Collins River system: Charles Creek, Barren Fork, West Fork Hickory 
Creek, and the upper Collins River. West Fork Hickory Creek feeds 
Hickory Creek, which feeds the lower Barren Fork upstream from the 
Barren Fork confluence with the Collins River (see figure 2, above). 
Charles Creek and Barren Fork feed the lower Collins River directly. 
The Barrens darter is extirpated

[[Page 28709]]

from the West Fork Hickory Creek system, where it was last collected in 
1982.
    Each of the three watersheds where the Barrens darter is extant and 
the watershed where it is extirpated is treated as a management unit 
(MU) in our SSA report (version 3.0: Service 2025, entire). To assess 
the current resiliency of the MUs, we selected seven metrics that 
included two habitat factors and five population factors (see table 1, 
below). For habitat factors, the physical habitat metric was determined 
using the Tennessee Department of Environment and Conservation (TDEC) 
stream habitat assessment protocol for moderate to high gradient 
streams (TDEC 2017, p. I.I-D-1-24). This protocol scores habitat 
quality based on factors such as sediment deposition, substrate 
availability, channel alteration, riparian vegetation, etc. Water 
quality was rated based on designations from the U.S. Environmental 
Protection Agency (USEPA) and TDEC, such as the List of Impaired and 
Threatened Waters (covered by CWA section 303(d)) (see Habitat Threats 
from Agricultural Activities and Riparian Clearing section, above) as 
well as observations from field surveys.
    We obtained population factor data from surveys and other records 
for the Barrens darter from 2009 through 2019 (Harrington et al. 2020, 
entire; Mattingly and Johansen 2017, entire; and Zuber 2014, entire). 
These survey efforts were standardized and used methods to specifically 
target darters across all size classes. Age structure criteria (high, 
moderate, or low categories) were based on the number of age classes 
present and whether juveniles were collected in the most recent survey. 
Due to population variability through time and across sites, as well as 
differential collection techniques between surveys, we characterized 
approximate abundance as the average number of Barrens darters 
collected at all the sites in a management unit. Occurrence extent was 
measured as the distance between the upstream-most and downstream-most 
occurrence record in a MU stream network, which approximated the size 
of the Barrens darter's range within each MU. Occurrence complexity 
describes the dispersion of the Barrens darter in each MU as the number 
of occupied tributaries feeding the mainstem. Presence of fringed 
darters characterizes the degree of threat they pose to Barrens darters 
via competition, hybridization, and likely replacement of Barrens 
darters once the two species come into contact. Within each MU, the 
fringed darter presence metric was measured as the ratio of streams 
occupied by the fringed darter to streams occupied by the Barrens 
darter. If fringed darters are present in a MU, the overall current 
resiliency is rated as low, given the scope and magnitude of this 
threat to the species, which outweigh all other threats combined.

                     Table 1--Factors and Criteria for Assessing Population (MU) Resiliency
----------------------------------------------------------------------------------------------------------------
           Factor                  Type             High           Moderate           Low           Unsuitable
----------------------------------------------------------------------------------------------------------------
Physical Habitat Score......  Habitat.......  151-200........  101-150........  0-100..........  Does not
                                                                                                  support
                                                                                                  survival.
Water Quality...............  Habitat.......  Minimal issues.  Issues           Issues known to  Does not
                                                                recognized,      impact           support
                                                                e.g., CWA        populations.     survival.
                                                                303(d) streams.
Age Structure...............  Population....  Two to three     One adult age    One age class..  Extirpated.
                                               age classes,     class and
                                               including        juveniles.
                                               juveniles.
Approximate Abundance.......  Population....  Greater than 15  5 to 15 fish     Fewer than 5     Extirpated.
                                               fish per 100     per 100 m (328   fish per 100 m
                                               meters (m)       ft).             (328 ft).
                                               (328 feet
                                               (ft)).
Occurrence Extent...........  Population....  Range greater    Range 5 to 10    Range less than  Extirpated.
                                               than 10 stream   stream mi (8.0   5 stream mi
                                               mi (16.1 km).    to 16.1 km).     (8.0 km).
Occurrence Complexity.......  Population....  Occupies main    Occupies main    Occupies main    Extirpated.
                                               channel and      channel and      channel only.
                                               multiple         one tributary.
                                               tributaries.
Fringed Darter Occurrence...  Population....  None in MU.....  Ratio of         Ratio of         Extirpated.
                                                                tributaries      tributaries
                                                                occupied by      occupied by
                                                                fringed darter   fringed darter
                                                                to those         to those
                                                                occupied by      occupied by
                                                                Barrens darter   Barrens darter
                                                                less than 50     greater than
                                                                percent.         50 percent.
----------------------------------------------------------------------------------------------------------------

    Currently, the Barren Fork and Charles Creek MUs have low 
resiliency, the Upper Collins River MU has moderate to high resiliency, 
and the Barrens darter is extirpated from the Hickory Creek MU (table 
2). Although occurrence extent is classified as ``high'' in the Upper 
Collins River and Barren Fork MUs, the stream lengths that approximate 
the range in these units are small, measuring 10.4 mi (16.7 km) and 
14.7 mi (23.7 km), respectively. The Barren Fork system's overall 
moderate habitat and water quality (table 2) derives from averaging the 
classifications for those two metrics in all streams currently and 
historically occupied by Barrens darters, although both metrics are low 
in some occupied streams (discussed below). Occurrence extent is only 1 
mi (1.6 km) in the Charles Creek unit, in a single reach of the 
mainstem (low occurrence complexity).

                                          Table 2--Classification of Resiliency Factors and Current Resiliency of Barrens Darter Management Units (MUs)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Approximate                            Occurrence       Fringed darter
               MU                 Physical habitat      Water quality       Age structure         abundance      Occurrence extent      complexity         presence *           Resiliency
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Charles Creek..................  Moderate..........  Moderate..........  Low...............  Low...............  Low..............  Low..............  Low..............  Low.
Barren Fork....................  Moderate..........  Moderate..........  High..............  High..............  High.............  Moderate.........  Low..............  Low.
Hickory Creek..................  Moderate..........  Low...............  Extirpated........  Extirpated........  Extirpated.......  Extirpated.......  Extirpated.......  None (Extirpated).
Upper Collins River............  Moderate-Low......  Low...............  High..............  Mod...............  High.............  High.............  High.............  Moderate-High.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Low resiliency rating is assigned for MUs with high levels of fringed darter presence.

    Considering the strong negative influence that fringed darters have 
on Barrens darters, coupled with the impacts of habitat and water 
quality impairment in some of its tributaries, the Barren Fork MU has 
low resiliency. Within the Barren Fork system since 2002, records of 
Barrens darters are from only Duke (includes McMahan Creek

[[Page 28710]]

and its tributary, Lewis Creek), Mud, and Liberty Creeks. In Mud Creek, 
fringed darters replaced Barrens darters between 2009 and 2018 
(Harrington et al. 2020, p. 17). Mud and Liberty Creeks have poor 
habitat quality and are listed as impaired by the State. By stream 
miles, Liberty Creek comprises just over one-third of the stream 
systems within the Barren Fork where the Barrens darter remains extant. 
The Barrens darter is extirpated from the North Prong Barren Fork 
system and Dog Branch, a direct tributary to mainstem Barren Fork. 
North Prong Barren Fork is listed as impaired by the State, and fringed 
darters currently occur in the lower end of Dog Branch. The mouth of 
Mud Creek is just below the current record of Barrens darter in Liberty 
Creek. Therefore, the Liberty Creek Barrens darters are at very high 
risk of fringed darter invasion, owing both to poor habitat and fringed 
darter proximity. The Duke Creek system is farther upstream (about 6 mi 
(9.7 km)) from fringed darter records, but fringed darters have been 
encroaching closer over the past 40 years. Water quality and habitat in 
Duke Creek is moderate, and one of its tributary systems, McMahan Creek 
(including Lewis Creek), has high habitat quality (Service 2018, p. 
24). As noted above (see Threats), Duke Creek and Lewis Creek, as well 
as other headwater streams in the Collins River system, have gone dry 
during moderate drought, which has the potential to put Barrens darters 
in contact with fringed darters as they move downstream to find watered 
stream channels.
    The ability of Barrens darters to disperse and recolonize 
tributaries where they once occurred is likely precluded by the 
occurrence of fringed darters along several pathways in the stream 
network comprising the Barren Fork MU. This MU has moderate complexity 
because there are three tributaries occupied by the Barrens darter but 
Barrens darters are absent from the mainstem. Because fringed darters 
are in the mainstem and have colonized several tributary systems in the 
Barren Fork MU, including the North Prong Barren Fork, Dog Branch, and 
Mud Creek systems (Harrington et al. 2020, pp. 17-19) where Barrens 
darters are extirpated, opportunities for Barrens darters to recolonize 
historically occupied tributaries are extremely reduced. Together, the 
occurrence of fringed darters in multiple tributaries, several stream 
reaches with poor habitat quality, and the threat of occasional 
moderate droughts contribute to the low resiliency of the Barrens 
darter in the Barren Fork MU.
    In addition to population (MU) resiliency, we assessed species 
redundancy, which is low. The Barrens darter is confined to three of 
its four historically occupied MUs, and two of those MUs, Charles Creek 
and Barren Fork, have low resiliency. Only the Upper Collins River MU 
has moderate to high resiliency. There is likely no connectivity 
allowing for dispersal from the Upper Collins River MU to colonize and 
``rescue'' the two low resiliency MUs because fringed darters are in 
the intervening stream reaches. With only one moderate to high 
resiliency MU, no connectivity between the three occupied MUs, and the 
close spatial arrangement of the three occupied MUs, which makes all of 
the occupied MUs vulnerable to incurring the same harmful effect of a 
catastrophic event, such as an extreme flood that passively pushes the 
species downstream or a drought that prompts dispersal downstream to 
sites occupied by fringed darters or that are unsuitable habitat, 
Barrens darter redundancy is low.
    Species representation is also low. The range of the Barrens darter 
is naturally narrow, consisting of headwater streams in the Collins 
River subbasin of the Caney Fork that drains four counties situated on 
the Barrens Plateau within a single physiographic province, the Eastern 
Highland Rim. There are no areas within the species' natural range that 
contain unique habitat features that might promote development of 
different adaptive traits. Genetic data show very little variation 
between the Charles Creek and Barren Fork populations. However, the 
Collins River population harbors a unique mitochondrial DNA (mtDNA) 
haplotype, and the frequency of (mtDNA) haplotypes in the Collins 
population is measurably different from Barren Fork and Charles Creek 
populations (Harrington et al. 2020, pp. 16-17). Although this spatial 
structuring of genetic variation is based on haplotypes from a single 
region of mtDNA (locus) and should be interpreted with caution until 
more loci can be assessed, it suggests there has been little recent 
gene flow between the Upper Collins River MU and the other MUs 
(Harrington et al. 2020, p. 16) and indicates there is potentially 
greater adaptive capacity within the upper Collins system. 
Nevertheless, Barrens darter representation is likely to erode over 
time because the unique alleles (gene variants) in the Upper Collins 
River MU that may bolster adaptive capacity cannot be shared with the 
rest of the basin where there is little allelic diversity due to a lack 
of connectivity among MUs. Overall, the Barrens darter's habitat 
diversity and genetic diversity are low, indicating the species' 
capacity to adapt to environmental changes, such as channel widening 
that can result from streambank alteration or novel exposure to a 
species such as the fringed darter, are limited. Therefore, the Barrens 
darter's representation is low.

Future Condition

    Considering the accumulation of the best scientific information to 
date on the severity of threats currently affecting the viability of 
the Barrens darter, which includes new data that clearly shows the 
imminence and high magnitude of the threat posed by the ongoing fringed 
darter expansion into or near streams occupied by the Barrens darter, 
we determined that the current condition of the Barrens darter is 
consistent with an endangered species (see Determination of Barrens 
Darter Status, below) and did not conduct a new future condition 
analysis for the SSA report (version 3.0: Service 2025, entire). As 
part of our initial SSA report (version 1.0: Service 2018, entire), we 
developed three future-condition scenarios to capture the range of 
uncertainties regarding future threats and the projected responses by 
the Barrens darter. Our scenarios considered three main elements of 
change: land development, conservation levels, and changes in 
precipitation and drought. The scenarios differ by considering 
variations that were forecast in each of the three elements of change 
and capture the range of outcomes the Barrens darter was expected to 
exhibit in the MUs by 2050. Effects of storms and drought were expected 
to worsen regardless of scenario, whereas projected development and 
conservation effects vary depending on scenario but were generally 
expected to remain similar to current levels or worsen. Please refer to 
the initial SSA report (Service 2018, pp. 25-39) for the full analysis 
of future scenarios.

Determination of Barrens Darter Status

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species meets the definition of an endangered species or a 
threatened species. The Act defines an ``endangered species'' as a 
species in danger of extinction throughout all or a significant portion 
of its range and a ``threatened species'' as a species likely to become 
an endangered species within the foreseeable future throughout all or a 
significant portion of its range. The

[[Page 28711]]

Act requires that we determine whether a species meets the definition 
of an endangered species or a threatened species because of any of the 
following factors: (A) The present or threatened destruction, 
modification, or curtailment of its habitat or range; (B) 
overutilization for commercial, recreational, scientific, or 
educational purposes; (C) disease or predation; (D) the inadequacy of 
existing regulatory mechanisms; or (E) other natural or manmade factors 
affecting its continued existence.

Status Throughout All of Its Range

    The Barrens darter has a small range, which has been reduced from 
its historical size. Barrens darters currently occur in three of four 
stream systems that we defined as management units (MUs) in our SSA 
report (Service 2025, entire): Charles Creek, Barren Fork, and the 
upper Collins River. The species is extirpated from the Hickory Creek 
system. In Charles Creek, the Barrens darter's known range consists of 
a single, linear, 1-mi (1.6 km) reach in the creek's mainstem. In 
Barren Fork and the upper Collins River, the extent of the Barrens 
darter's range (upstream to downstream-most occurrence) is 14.7 and 
10.4 mi (23.7 and 16.7 km), respectively.
    Some streams within each MU are listed by the State of Tennessee as 
having impaired water and habitat quality along their entire length. 
Degraded habitat likely provides conditions favorable for invasion by 
fringed darters, and Barrens darters have been completely replaced in 
all streams colonized by fringed darters, including in the entire 
Hickory Creek MU. Species replacement has been rapid, with Barrens 
darters disappearing within 15 years after contact between the two 
species.
    Overall, the resiliency, redundancy, and representation of the 
Barrens darter are low. Population resiliency in Charles Creek is low, 
given the 1-mi (1.6-km), single occupied stream segment, and fringed 
darter occupation of the downstream reach. Resiliency in the Barren 
Fork also is low due the ongoing colonization of upstream reaches by 
the fringed darter, and poor habitat conditions in some stream reaches 
that favor the fringed darter and directly impact Barrens darter 
populations via sedimentation and reduced cover. Resiliency in the 
Upper Collins River MU is moderate to high, but there is no 
connectivity between the Upper Collins River MU and the other MUs. 
Barrens darter redundancy is low. Among the three extant MUs, Charles 
Creek and the Barren Fork contribute little to redundancy, due to their 
low resiliency. In addition, the close spatial arrangement of the MUs 
leaves the species vulnerable to the effects of a single catastrophic 
event. For example, an extreme or prolonged drought would likely affect 
the entire range of the species, with individuals that survive 
desiccation by moving downstream encountering fringed darters. An 
extreme flooding event would likely affect the entire range of the 
species by scouring or smothering nesting habitat and washing 
individuals downstream and into contact with fringed darters. 
Representation is low because the breadth of occupied habitat types and 
number of physiographic regions occupied by Barrens darters is 
naturally low, and genetic diversity is low rangewide, except for a 
unique genetic marker in the Upper Collins River MU that cannot be 
shared with the other MU populations because of the lost connectivity.
    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we find that the primary threats influencing the viability of 
the Barrens darter are habitat loss; degradation of stream banks, 
instream cover, and water quality; and habitat fragmentation and 
isolation (Factor A); and the invasion of Barrens darter-occupied 
streams by the fringed darter (Factor E). The scope, magnitude, and 
imminency of these threats have reduced the resiliency, redundancy, and 
representation of the Barrens darter such that the species is in danger 
of extinction throughout its range. We did not identify threats to the 
continued existence of the Barrens darter due to overutilization for 
commercial, recreational, scientific, or educational purposes (Factor 
B); or disease or predation (Factor C). After evaluating the threats to 
the species, we found that past and ongoing changes in habitat, 
together with the current number of Barrens darter sites colonized by 
fringed darters, result in conditions that present a high risk of 
extinction for the Barrens darter. Thus, after assessing the best 
scientific and commercial data available, we determine that the Barrens 
darter is in danger of extinction throughout all of its range.

Status Throughout a Significant Portion of Its Range

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
within the foreseeable future throughout all or a significant portion 
of its range. We have determined that the Barrens darter is in danger 
of extinction throughout all of its range and accordingly did not 
undertake an analysis of any significant portion of its range. Because 
the Barrens darter warrants listing as endangered throughout all of its 
range, our determination does not conflict with the decision in Center 
for Biological Diversity v. Everson, 435 F. Supp. 3d 69 (D.D.C. 2020), 
because that decision related to significant portion of the range 
analyses for species that warrant listing as threatened, not 
endangered, throughout all of their ranges.

Determination of Status

    Based on the best scientific and commercial data available, we 
determine that the Barrens darter meets the Act's definition of an 
endangered species. Therefore, we propose to list the Barrens darter as 
an endangered species in accordance with sections 3(6) and 4(a)(1) of 
the Act.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened species under the Act include recognition as a listed 
species, planning and implementation of recovery actions, requirements 
for Federal protection, and prohibitions against certain practices. 
Recognition through listing results in public awareness, and 
conservation by Federal, State, Tribal, and local agencies, foreign 
governments, private organizations, and individuals. The Act encourages 
cooperation with the States and other countries and calls for recovery 
actions to be carried out for listed species. The protection required 
by Federal agencies, including the Service, and the prohibitions 
against certain activities are discussed, in part, below.
    The primary purpose of the Act is the conservation of endangered 
and threatened species and the ecosystems upon which they depend. The 
ultimate goal of such conservation efforts is the recovery of these 
listed species, so that they no longer need the protective measures of 
the Act. Section 4(f) of the Act calls for the Service to develop and 
implement recovery plans for the conservation of endangered and 
threatened species. The goal of this process is to restore listed 
species to a point where they are secure, self-sustaining, and 
functioning components of their ecosystems.

[[Page 28712]]

    The recovery planning process begins with development of a recovery 
outline made available to the public soon after a final listing 
determination. The recovery outline guides the immediate implementation 
of urgent recovery actions while a recovery plan is being developed. 
Recovery teams (composed of species experts, Federal and State 
agencies, nongovernmental organizations, and stakeholders) may be 
established to develop and implement recovery plans. The recovery 
planning process involves the identification of actions that are 
necessary to halt and reverse the species' decline by addressing the 
threats to its survival and recovery. The recovery plan identifies 
recovery criteria for review of when a species may be ready for 
reclassification from endangered to threatened (``downlisting'') or 
removal from protected status (``delisting''), and methods for 
monitoring recovery progress. Recovery plans also establish a framework 
for agencies to coordinate their recovery efforts and provide estimates 
of the cost of implementing recovery tasks. Revisions of the plan may 
be done to address continuing or new threats to the species, as new 
substantive information becomes available. The recovery outline, draft 
recovery plan, final recovery plan, and any revisions will be available 
on our website as they are completed (/program/endangered-species) or from our Tennessee Ecological Services Field 
Office (see FOR FURTHER INFORMATION CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribes, nongovernmental organizations, businesses, 
and private landowners. Examples of recovery actions include habitat 
restoration (e.g., restoration of native vegetation), research, captive 
propagation and reintroduction, and outreach and education. The 
recovery of many listed species cannot be accomplished solely on 
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires 
cooperative conservation efforts on private, State, and Tribal lands.
    If this species is listed, funding for recovery actions may be 
available from a variety of sources, including Federal budgets, State 
programs, and cost-share grants for non-Federal landowners, the 
academic community, and nongovernmental organizations. In addition, 
pursuant to section 6 of the Act, the State of Tennessee would be 
eligible for Federal funds to implement management actions that promote 
the protection or recovery of the Barrens darter. Information on our 
grant programs that are available to aid species recovery can be found 
at: /service/financial-assistance.
    Although the Barrens darter is only proposed for listing under the 
Act at this time, please let us know if you are interested in 
participating in recovery efforts for this species. Additionally, we 
invite you to submit any new information on this species whenever it 
becomes available and any information you may have for recovery 
planning purposes (see FOR FURTHER INFORMATION CONTACT).
    Section 7 of the Act is titled, ``Interagency Cooperation,'' and it 
mandates all Federal action agencies to use their existing authorities 
to further the conservation purposes of the Act and to ensure that 
their actions are not likely to jeopardize the continued existence of 
listed species or adversely modify critical habitat. Regulations 
implementing section 7 are codified at 50 CFR part 402.
    Section 7(a)(2) states that each Federal action agency shall, in 
consultation with the Secretary, ensure that any action they authorize, 
fund, or carry out is not likely to jeopardize the continued existence 
of a listed species or result in the destruction or adverse 
modification of designated critical habitat. Each Federal agency shall 
review its action at the earliest possible time to determine whether it 
may affect listed species or critical habitat. If a determination is 
made that the action may affect listed species or critical habitat, 
formal consultation is required (50 CFR 402.14(a)), unless the Service 
concurs in writing that the action is not likely to adversely affect 
listed species or critical habitat. At the end of a formal 
consultation, the Service issues a biological opinion, containing its 
determination of whether the Federal action is likely to result in 
jeopardy or adverse modification.
    In contrast, section 7(a)(4) of the Act requires Federal agencies 
to confer with the Service on any action which is likely to jeopardize 
the continued existence of any species proposed to be listed under the 
Act or result in the destruction or adverse modification of critical 
habitat proposed to be designated for such species. Although the 
conference procedures are required only when an action is likely to 
result in jeopardy or adverse modification, action agencies may 
voluntarily confer with the Service on actions that may affect species 
proposed for listing or critical habitat proposed to be designated. In 
the event that the subject species is listed or the relevant critical 
habitat is designated, a conference opinion may be adopted as a 
biological opinion and serve as compliance with section 7(a)(2) of the 
Act.
    Examples of discretionary actions for the Barrens darter that may 
be subject to conference and consultation procedures under section 7 
are actions that require a Federal permit (such as a permit from the 
U.S. Army Corps of Engineers under section 404 of the CWA (33 U.S.C. 
1251 et seq.)) or actions funded by Federal agencies such as the 
Federal Highway Administration, the U.S. Department of Agriculture's 
Natural Resources Conservation Service, or the Federal Emergency 
Management Agency. Federal actions not affecting listed species or 
critical habitat--and actions on State, Tribal, local, or private lands 
that are not federally funded, authorized, or carried out by a Federal 
agency--do not require section 7 consultation. Federal agencies should 
coordinate with the Tennessee Ecological Services Field Office (see FOR 
FURTHER INFORMATION CONTACT) with any specific questions on section 7 
consultation and conference requirements.
    The Act and its implementing regulations set forth a series of 
prohibitions and exceptions that apply to endangered wildlife. The 
prohibitions of section 9(a)(1) of the Act, and the Service's 
implementing regulations codified at 50 CFR 17.21, make it illegal for 
any person subject to the jurisdiction of the United States to commit, 
to attempt to commit, to solicit another to commit, or to cause to be 
committed any of the following acts with regard to any endangered 
wildlife: (1) import into, or export from, the United States; (2) take 
(which includes harass, harm, pursue, hunt, shoot, wound, kill, trap, 
capture, or collect, or to attempt to engage in any such conduct) 
within the United States, within the territorial sea of the United 
States, or on the high seas; (3) possess, sell, deliver, carry, 
transport, or ship, by any means whatsoever, any such wildlife that has 
been taken illegally; (4) deliver, receive, carry, transport, or ship 
in interstate or foreign commerce, by any means whatsoever and in the 
course of commercial activity; or (5) sell or offer for sale in 
interstate or foreign commerce. Certain exceptions to these 
prohibitions apply to employees or agents of the Service, the National 
Marine Fisheries Service, other Federal land management agencies, and 
State conservation agencies.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered wildlife under certain circumstances. Regulations

[[Page 28713]]

governing permits for endangered wildlife are codified at 50 CFR 17.22, 
and general Service permitting regulations are codified at 50 CFR part 
13. With regard to endangered wildlife, a permit may be issued: for 
scientific purposes, for enhancing the propagation or survival of the 
species, or for take incidental to otherwise lawful activities. The 
statute also contains certain exemptions from the prohibitions, which 
are found in sections 9 and 10 of the Act.

II. Critical Habitat

Background

    Section 4(a)(3) of the Act requires that, to the maximum extent 
prudent and determinable, we designate a species' critical habitat 
concurrently with listing the species. Critical habitat is defined in 
section 3(5)(A) of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features.
    (a) Essential to the conservation of the species, and
    (b) Which may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Our regulations at 50 CFR 424.02 define the geographical area 
occupied by the species as an area that may generally be delineated 
around species' occurrences, as determined by the Secretary (i.e., 
range). Such areas may include those areas used throughout all or part 
of the species' life cycle, even if not used on a regular basis (e.g., 
migratory corridors, seasonal habitats, and habitats used periodically, 
but not solely by vagrant individuals).
    Conservation, as defined under section 3(3) of the Act, means to 
use and the use of all methods and procedures that are necessary to 
bring an endangered or threatened species to the point at which the 
measures provided pursuant to the Act are no longer necessary. Such 
methods and procedures include, but are not limited to, all activities 
associated with scientific resources management such as research, 
census, law enforcement, habitat acquisition and maintenance, 
propagation, live trapping, and transplantation, and, in the 
extraordinary case where population pressures within a given ecosystem 
cannot be otherwise relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that each Federal action agency ensure, in 
consultation with the Service, that any action they authorize, fund, or 
carry out is not likely to result in the destruction or adverse 
modification of designated critical habitat. The designation of 
critical habitat does not affect land ownership or establish a refuge, 
wilderness, reserve, preserve, or other conservation area. Such 
designation also does not allow the government or public to access 
private lands. Such designation does not require implementation of 
restoration, recovery, or enhancement measures by non-Federal 
landowners. Rather, designation requires that, where a landowner 
requests Federal agency funding or authorization for an action that may 
affect an area designated as critical habitat, the Federal agency 
consult with the Service under section 7(a)(2) of the Act. If the 
action may affect the listed species itself (such as for occupied 
critical habitat), the Federal agency would have already been required 
to consult with the Service even absent the designation because of the 
requirement to ensure that the action is not likely to jeopardize the 
continued existence of the listed species. Even if the Service were to 
conclude after consultation that the proposed activity is likely to 
result in destruction or adverse modification of the critical habitat, 
the Federal action agency and the landowner are not required to abandon 
the proposed activity, or to restore or recover the species; instead, 
they must implement ``reasonable and prudent alternatives'' to avoid 
destruction or adverse modification of critical habitat.
    Under the first prong of the Act's definition of critical habitat, 
areas within the geographical area occupied by the species at the time 
it was listed are included in a critical habitat designation if they 
contain physical or biological features (1) which are essential to the 
conservation of the species and (2) which may require special 
management considerations or protection. For these areas, critical 
habitat designations identify, to the extent known using the best 
scientific data available, those physical or biological features that 
are essential to the conservation of the species (such as space, food, 
cover, and protected habitat).
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in areas outside the geographical 
area occupied by the species at the time it is listed, upon a 
determination that such areas are essential for the conservation of the 
species.
    Section 4(b)(2) of the Act requires that we designate critical 
habitat on the basis of the best scientific data available. Further, 
our Policy on Information Standards Under the Endangered Species Act 
(published in the Federal Register on July 1, 1994 (59 FR 34271)), the 
Information Quality Act (section 515 of the Treasury and General 
Government Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; 
H.R. 5658)), and our associated Information Quality Guidelines provide 
criteria, establish procedures, and provide guidance to ensure that our 
decisions are based on the best scientific data available. They require 
our biologists, to the extent consistent with the Act and with the use 
of the best scientific data available, to use primary and original 
sources of information as the basis for recommendations to designate 
critical habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information compiled in the SSA report and information developed during 
the listing process for the species. Additional information sources may 
include any generalized conservation strategy, criteria, or outline 
that may have been developed for the species; the recovery plan for the 
species; articles in peer-reviewed journals; conservation plans 
developed by States and counties; scientific status surveys and 
studies; biological assessments; other unpublished materials; or 
experts' opinions or personal knowledge.
    Habitat is dynamic, and species may move from one area to another 
over time. We recognize that critical habitat designated at a 
particular point in time may not include all of the habitat areas that 
we may later determine are necessary for the recovery of the species. 
For these reasons, a critical habitat designation does not signal that 
habitat outside the designated area is unimportant or may not be needed 
for recovery of the species. Areas that are important to the 
conservation of the species, both inside and outside the critical 
habitat designation, will continue to be subject to:

[[Page 28714]]

(1) Conservation actions implemented under section 7(a)(1) of the Act; 
(2) regulatory protections afforded by the requirement in section 
7(a)(2) of the Act for Federal agencies to ensure their actions are not 
likely to jeopardize the continued existence of any endangered or 
threatened species; and (3) the prohibitions found in section 9 of the 
Act. Federally funded or permitted projects affecting listed species 
outside their designated critical habitat areas may still result in 
jeopardy findings in some cases. These protections and conservation 
tools will continue to contribute to recovery of the species. 
Similarly, critical habitat designations made on the basis of the best 
scientific data available at the time of designation will not control 
the direction and substance of future recovery plans, habitat 
conservation plans (HCPs), or other species conservation planning 
efforts if new information available at the time of those planning 
efforts calls for a different outcome.

Critical Habitat Determinability

    Our regulations at 50 CFR 424.12(a)(2) state that critical habitat 
is not determinable when one or both of the following situations exist:
    (i) Data sufficient to perform required analyses are lacking, or
    (ii) The biological needs of the species are not sufficiently well 
known to identify any area that meets the definition of ``critical 
habitat.''
    We reviewed the available information pertaining to the biological 
needs of the Barrens darter and habitat characteristics where the 
species is located. A careful assessment of the economic impacts is 
pending, and we will begin working to acquire the complex information 
needed to perform that assessment. Therefore, due to the current lack 
of data sufficient to perform required analyses, we conclude that the 
designation of critical habitat for the Barrens darter is not 
determinable at this time. The Act allows the Service an additional 
year to publish a critical habitat designation that is not determinable 
at the time of listing (16 U.S.C. 1533(b)(6)(C)(ii)).

Required Determinations

Clarity of the Proposed Rule

    We are required by Executive Orders (E.O.s) 12866 and 12988 and by 
the Presidential memorandum of June 1, 1998, to write all rules in 
plain language. This means that each rule we publish must:
    (1) Be logically organized;
    (2) Use the active voice to address readers directly;
    (3) Use clear language rather than jargon;
    (4) Be divided into short sections and sentences; and
    (5) Use lists and tables wherever possible.
    If you feel that we have not met these requirements, send us 
comments by one of the methods listed in ADDRESSES. To better help us 
revise the rule, your comments should be as specific as possible. For 
example, you should tell us the numbers of the sections or paragraphs 
that are unclearly written, which sections or sentences are too long, 
the sections where you feel lists or tables would be useful, etc.

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994 
(Government-to-Government Relations with Native American Tribal 
Governments; 59 FR 22951, May 4, 1994), E.O. 13175 (Consultation and 
Coordination with Indian Tribal Governments), the President's 
memorandum of November 30, 2022 (Uniform Standards for Tribal 
Consultation; 87 FR 74479, December 5, 2022), and the Department of the 
Interior's manual at 512 DM 2, we readily acknowledge our 
responsibility to communicate meaningfully with federally recognized 
Tribes and Alaska Native Corporations on a government-to-government 
basis. In accordance with Secretary's Order 3206 of June 5, 1997 
(American Indian Tribal Rights, Federal-Tribal Trust Responsibilities, 
and the Endangered Species Act), we readily acknowledge our 
responsibilities to work directly with Tribes in developing programs 
for healthy ecosystems, to acknowledge that Tribal lands are not 
subject to the same controls as Federal public lands, to remain 
sensitive to Indian culture, and to make information available to 
Tribes. We have determined that no Tribal lands fall within the 
boundaries of the proposed critical habitat for the Barrens darter, so 
no Tribal lands would be affected by the proposed designation.

References Cited

    A complete list of references cited in this rulemaking is available 
on the internet at  and upon request from 
the Tennessee Ecological Services Field Office (see FOR FURTHER 
INFORMATION CONTACT).

List of Subjects in 50 CFR Part 17

    Endangered and threatened species, Exports, Imports, Plants, 
Reporting and recordkeeping requirements, Transportation, Wildlife.

Signing Authority

    Paul Souza, Regional Director, Region 8, Exercising the Delegated 
Authority of the Director of the U.S. Fish and Wildlife Service, 
approved this action on June 6, 2025, for publication. On June 25, 
2025, Paul Souza authorized the undersigned to sign the document 
electronically and submit it to the Office of the Federal Register for 
publication as an official document of the U.S. Fish and Wildlife 
Service.

Proposed Regulation Promulgation

    Accordingly, we propose to amend part 17, subchapter B of chapter 
I, title 50 of the Code of Federal Regulations, as set forth below:

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

0
1. The authority citation for part 17 continues to read as follows:

    Authority:  16 U.S.C. 1361-1407; 1531-1544; and 4201-4245, 
unless otherwise noted.

0
2. In Sec.  17.11, in paragraph (h), amend the List of Endangered and 
Threatened Wildlife by adding an entry for ``Darter, Barrens'' in 
alphabetical order under FISHES to read as follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

----------------------------------------------------------------------------------------------------------------
                                                                                              Listing citations
           Common name                Scientific name        Where listed         Status        and applicable
                                                                                                    rules
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                                     Fishes
----------------------------------------------------------------------------------------------------------------
 

[[Page 28715]]

 
                                                  * * * * * * *
Darter, Barrens..................  Etheostoma forbesi..  Wherever found.....  E              [Federal Register
                                                                                              citation when
                                                                                              published as a
                                                                                              final rule].
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


Madonna Baucum,
Regulations and Policy Chief, Division of Policy, Economics, Risk 
Management, and Analytics of the Joint Administrative Operations, U.S. 
Fish and Wildlife Service.
[FR Doc. 2025-12009 Filed 6-30-25; 8:45 am]
BILLING CODE 4333-15-P