Endangered and Threatened Wildlife and Plants; Endangered Species Status for Tennessee Clubshell, Tennessee Pigtoe, and Cumberland Moccasinshell, 57060-57077 [2023-17844]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 88, Number 161 (Tuesday, August 22, 2023)]
[Proposed Rules]
[Pages 57060-57077]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-17844]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2023-0112; FF09E21000 FXES1111090FEDR 234]
RIN 1018-BE94


Endangered and Threatened Wildlife and Plants; Endangered Species 
Status for Tennessee Clubshell, Tennessee Pigtoe, and Cumberland 
Moccasinshell

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 three Tennessee and Cumberland River basin mussel species, the 
Tennessee clubshell (Pleurobema oviforme), Tennessee pigtoe (Pleuronaia 
barnesiana), and Cumberland moccasinshell (Medionidus conradicus), as 
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 three species. After a review of the best 
available scientific and commercial information, we find that listing 
the Tennessee clubshell, Tennessee pigtoe, and Cumberland moccasinshell 
as endangered species is warranted. If we finalize this rule as 
proposed, it would extend the Act's protections to these species.

DATES: We will accept comments received or postmarked on or before 
October 23, 2023. 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 October 6, 2023.

ADDRESSES: Written comments: You may submit comments by one of the 
following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal: https://www.regulations.gov. In the Search box, enter FWS-R4-ES-2023-0112, 
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-2023-0112, 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 https://www.regulations.gov. 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 at https://www.regulations.gov at Docket No. FWS-R4-ES-2023-0112.

FOR FURTHER INFORMATION CONTACT: Janet Mizzi, Field Supervisor, U.S. 
Fish and Wildlife Service, Asheville Ecological Services Field Office, 
160 Zillicoa St., Asheville, NC 28801; telephone 828-258-3939. 
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.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. Under the Act (16 U.S.C. 1531 et 
seq.), a species warrants listing if it meets the definition of an 
endangered species (in danger of extinction throughout all or a 
significant portion of its range) or a threatened species (likely to 
become endangered within the foreseeable future throughout all or a 
significant portion of its range). If we determine that a species 
warrants listing, we must list the species promptly and designate the 
species' critical habitat to the maximum extent prudent and 
determinable. We have determined that the Tennessee clubshell, 
Tennessee pigtoe, and Cumberland moccasinshell meet the Act's 
definition of an endangered species; therefore, we are proposing to 
list them as such. Listing a species as an endangered or threatened 
species can be completed only by issuing a rule through the 
Administrative Procedure Act rulemaking process (5 U.S.C. 551 et seq.).
    What this document does. This document proposes to list the 
Tennessee clubshell (Pleurobema oviforme), Tennessee pigtoe (Pleuronaia 
barnesiana), and Cumberland moccasinshell (Medionidus conradicus) as 
endangered species.
    The basis for our action. Under the Act, we may determine that a 
species is an endangered or threatened species because of any of five 
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. We have determined that the primary threats to all 
three species are large impoundments, urban development, energy 
development, and agriculture, which have altered natural flow regimes 
and/or diminished water and substrate quality (Factor A).

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

[[Page 57061]]

scientific community, industry, or any other interested parties 
concerning this proposed rule.
    We particularly seek comments concerning:
    (1) The species' biology, ranges, 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 ranges, including distribution patterns 
and the locations of any additional populations of these species;
    (d) Historical and current population levels, and current and 
projected trends; and
    (e) Past and ongoing conservation measures for these species, their 
habitats, 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 these species; and
    (c) Existing regulations or conservation actions that may be 
addressing threats to these species.
    (3) Additional information concerning the historical and current 
status of these species, including whether any of the species may 
warrant listing as a threatened species or may not warrant listing.
    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. 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.
    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 https://www.regulations.gov, 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 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 https://www.regulations.gov.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on https://www.regulations.gov.
    Because we will consider all comments and information we receive 
during the comment period, our final determinations may differ from 
this proposal. Based on the new information we receive (and any 
comments on that new information), we may conclude that any of these 
species are threatened instead of endangered, or we may conclude that 
any of these species do not warrant listing as either an endangered 
species or a threatened species.

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

    On April 20, 2010, we received a petition from the Center for 
Biological Diversity (CBD), Alabama Rivers Alliance, Clinch Coalition, 
Dogwood Alliance, Gulf Restoration Network, Tennessee Forests Council, 
and West Virginia Highlands Conservancy to list 404 aquatic, riparian, 
and wetland species, including the Tennessee clubshell, Tennessee 
pigtoe, and Cumberland moccasinshell, as endangered or threatened 
species under the Act. In response to the petition, we published a 
partial 90-day finding on September 27, 2011 (76 FR 59836), in which we 
announced our finding that the petition contained substantial 
information indicating that listing may be warranted for numerous 
species, including the Tennessee clubshell, Tennessee pigtoe, and 
Cumberland moccasinshell. This document serves as both our 12-month 
warranted petition finding and our proposed rule to list these species.

Peer Review

    A species status assessment (SSA) team prepared an SSA report for 
the Tennessee clubshell, Tennessee pigtoe, and Cumberland 
moccasinshell. The SSA team was composed of Service biologists, in 
consultation with other species experts. The SSA report represents a 
compilation of the best scientific and commercial data available 
concerning the status of the species, including the impacts of past, 
present, and future factors (both negative and beneficial) affecting 
the species. After the SSA report was completed, the methodology used 
to evaluate the status of the three species was published in a peer-
reviewed journal (Fitzgerald et al. 2021, entire).
    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 of 
listing actions under the Act, we solicited independent scientific 
review of the information contained in the SSA report. The Service sent 
the SSA report to three independent peer reviewers and received one 
response. Results of this structured peer review process can be found 
at https://www.regulations.gov and the Asheville Ecological Services 
Field Office (see FOR FURTHER INFORMATION CONTACT). In preparing this 
proposed rule, we incorporated the results of this review, as 
appropriate, into the SSA report, which is the foundation for this 
proposed rule.

Summary of Peer Reviewer Comments

    As discussed in Peer Review above, we received comments from one 
peer reviewer on the draft SSA report. We reviewed all comments we 
received from the peer reviewer for substantive issues and new 
information regarding the information contained in the SSA report. The 
peer reviewer agreed with our assessment of the status of the three 
mussel species. All substantive comments from the peer reviewer 
concerned the omission of coal mining as an important threat to the 
three species and included a recommendation to add references from 
peer-reviewed literature that illustrate the impact coal mining has had 
on freshwater mussels

[[Page 57062]]

in the species' ranges. To address the reviewer's comment, in this 
proposed rule, we clarify that our modeling approach focuses on 
rangewide drivers of population conditions and does not capture some 
site-specific threats with high consequences, such as coal mining. Coal 
mining drainage affects, very roughly, less than half the historical 
range of the three species. Because a little more than half of that 
range lacks coal mining impacts, mining does not explain rangewide 
patterns of population condition and was not included in the final 
model. Our SSA report explains that the negative effects of mining on 
mussels in this region have been well-documented, and the risk posed by 
this threat must be considered in addition to the model estimates 
presented, particularly for watersheds in the upper Tennessee and 
Cumberland River basins. As recommended by the peer reviewer, in this 
proposed rule, we include references from peer-reviewed literature that 
explain how coal mining has affected mussels in the range of the three 
mussel species.

I. Proposed Listing Determination

Background

General Mussel Biology

    Freshwater mussels, including the three species that are the 
subjects of this proposed rule, have a complex reproduction process 
involving parasitic larvae, called glochidia, that are wholly dependent 
on host fish. Mussels release sperm into the water column, which is 
taken in by the female, wherein fertilization and development of 
glochidia occurs in a restricted portion of the gills, called the brood 
pouch or marsupium. When mature, the glochidia are released to the 
water column to attach on the gills, head, or fins of fishes. Glochidia 
die if they fail to attach to a host fish, attach to an incompatible 
fish species, or attach to the wrong location on a host fish (Neves 
1991, p. 254; Bogan 1993, p. 599). Once attached to the host, glochidia 
draw nutrients from the fish's tissue as they develop (Arey 1932, pp. 
214-215). Time to development, from attachment of glochidia to 
maturation, ranges from just over 1 week to 6 weeks or more (Parmalee 
and Bogan 1998, p. 8).
    Depending on the species, mussels are either short-term or long-
term brooders. In short-term brooders, fertilization occurs in the 
spring or summer and glochidia are released shortly after they are 
fully developed. In long-term brooders, fertilization occurs in late 
summer or fall, and developed glochidia are held over winter and 
released in the following spring or summer (Haag 2012, pp. 39-40). 
Mature glochidia drop off their hosts and, if they settle in suitable 
habitat on the stream bottom, continue the remainder of their existence 
as free-living mussels. Newly released glochidia are juveniles that are 
reproductively immature but otherwise resemble adults, with both halves 
(valves) of the shell developed and poised for growth.
    Freshwater mussels are relatively sedentary and, under their own 
power, capable of moving only short horizontal distances, typically up 
to a few yards or less in a year (Haag 2012, pp. 34-35). Given mussels' 
limited mobility, host fish are their primary mode of dispersal, and 
the hosts are essential for maintaining population connectivity. Host 
specificity varies, with some mussel species being compatible with a 
few fish species while others can transform from glochidia to juveniles 
on several fish species.

Tennessee Clubshell

    A thorough review of the taxonomy, life history, and ecology of the 
Tennessee clubshell is presented in the SSA report (Service 2020, pp. 
3-7).
    Attaining a maximum length of approximately 90 millimeters (mm) (4 
inches (in)), the Tennessee clubshell is oval to triangular shaped and 
has a tawny to brown shell, usually with wide, broken green rays 
(Williams et al. 2008, p. 542). It occurs in the Tennessee and 
Cumberland River drainages in Alabama, Georgia, Kentucky, North 
Carolina, Tennessee, and Virginia (see figure 1, below). Favoring 
moderately swift currents, it is found in riffles and shoals of small 
streams to large rivers, in a mixture of sand, gravel, and cobble 
substrates.
    The Tennessee clubshell has a lifespan of 30 years on average but 
may live to 50 years. Age at maturity ranges from 4 to 6 years. In 
total, 10 host fish species in the minnow and darter families have been 
documented by observations of either attachment or metamorphosis of 
glochidia (Service 2020, pp. 5-6). As a short-term brooder, the 
Tennessee clubshell spawns in the spring and releases glochidia mid-
July through early August.

[[Page 57063]]

[GRAPHIC] [TIFF OMITTED] TP22AU23.050

Tennessee Pigtoe

    A thorough review of the taxonomy, life history, and ecology of the 
Tennessee pigtoe is presented in the SSA report (Service 2020, pp. 3-
7).
    Attaining a maximum length of 95 mm (3.7 in), the Tennessee 
pigtoe's shape varies from oval to subtriangular or subquadrate, and 
its shell is yellowish or brown, sometimes with dark green rays 
(Williams et al. 2008, p. 585). It occurs in the Tennessee River 
drainage, in Alabama, Georgia, North Carolina, Tennessee, and Virginia 
(see figure 2, below). It is presumed extirpated from Mississippi, 
where it was known to occur only in Bear Creek, in Tishomingo County. 
Unlike the Tennessee clubshell and Cumberland moccasinshell, the 
Tennessee pigtoe does not occur in the Cumberland River drainage. It is 
found in moderate current, and rarely in pools and slackwaters, in 
small streams to large rivers, in a mixture of sand, gravel, and cobble 
substrates.
    The Tennessee pigtoe has a lifespan of 30 years on average but may 
live to 50 years. Age at maturity ranges from 4 to 6 years. As a short-
term brooder, it spawns in the spring and releases glochidia mid-July 
through early August. The host fishes are unknown for this species but 
likely are the same as or similar to those of the Tennessee clubshell.

[[Page 57064]]

[GRAPHIC] [TIFF OMITTED] TP22AU23.051

Cumberland Moccasinshell

    A thorough review of the taxonomy, life history, and ecology of the 
Cumberland moccasinshell is presented in the SSA report (Service 2020, 
pp. 3-7).
    Attaining a maximum length of 60 mm (2.4 in), the Cumberland 
moccasinshell is elliptical shaped, slightly bowing or arching with 
age. Its shell is yellowish to tawny or brown and usually covered in 
green rays, and the posterior of the shell is usually marked with small 
ridges (Williams et al. 2008, p. 434). The Cumberland moccasinshell 
occurs in the Tennessee and Cumberland River drainages in Alabama, 
Georgia, Kentucky, Tennessee, and Virginia (see figure 3, below). It is 
presumed extirpated in North Carolina. Favoring strong currents, it is 
found in riffles and shoals of streams ranging from headwaters to 
medium-sized rivers amongst gravel, cobble, boulder, and occasionally 
sand and gravel substrates. It is sometimes found under large flat 
rocks or cracks in bedrock.
    The Cumberland moccasinshell has a lifespan of approximately 10 
years on average, with a maximum reported age of 24 years, based on 
shells from the Clinch River in Virginia and Tennessee (Scott 1994, pp. 
16, 71). Age at maturity ranges from 1 to 3 years (Zale and Neves 1982, 
p. 19; T. Lane 2023, pers. comm.). Fish hosts include at least four 
(possibly six) species in the darter genus, Etheostoma (Service 2020, 
pp. 5-6). As a long-term brooder, the Cumberland moccasinshell spawns 
mid-July and releases glochidia sporadically September through 
November, with peak releases occurring January through May (Zale and 
Neves 1982, p. 25).

[[Page 57065]]

[GRAPHIC] [TIFF OMITTED] TP22AU23.052

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. In 2019, jointly with the National Marine Fisheries 
Service, the Service issued a final rule that revised the regulations 
in 50 CFR part 424 regarding how we add, remove, and reclassify 
endangered and threatened species and the criteria for designating 
listed species' critical habitat (84 FR 45020; August 27, 2019). On the 
same day, the Service also issued final regulations that, for species 
listed as threatened species after September 26, 2019, eliminated the 
Service's general protective regulations automatically applying to 
threatened species the prohibitions that section 9 of the Act applies 
to endangered species (84 FR 44753; August 27, 2019).
    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;
    (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

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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 now and in the 
foreseeable future.
    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. The term 
``foreseeable future'' extends only so far into the future as we can 
reasonably determine that both the future threats and the species' 
responses to those threats are likely. In other words, the foreseeable 
future is the period of time in which we can make reliable predictions. 
``Reliable'' does not mean ``certain''; it means sufficient to provide 
a reasonable degree of confidence in the prediction. Thus, a prediction 
is reliable if it is reasonable to depend on it when making decisions.
    It is not always possible or necessary to define the foreseeable 
future as a particular number of years. Analysis of the foreseeable 
future uses the best scientific and commercial data available and 
should consider the timeframes applicable to the relevant threats and 
to the species' likely responses to those threats in view of its life-
history characteristics. Data that are typically relevant to assessing 
the species' biological response include species-specific factors such 
as lifespan, reproductive rates or productivity, certain behaviors, and 
other demographic factors.

Analytical Framework

    The SSA report documents the results of our comprehensive 
biological review of the best scientific and commercial data regarding 
the status of these species, including an assessment of the potential 
threats to the species. The SSA report does not represent our decision 
on whether these species should be proposed for listing as 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 Tennessee clubshell, Tennessee 
pigtoe, and Cumberland moccasinshell, 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, reduced 
birth rates), 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 or 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. 
For each of the three species, 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 available information 
to characterize viability as the ability of a species to sustain 
populations in the wild over time. We use this information 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-2023-0112 on https://www.regulations.gov and at the Service's 
Environmental Conservation Online System species profile pages: https://ecos.fws.gov/ecp/species/3254; https://ecos.fws.gov/ecp/species/9887; 
and https://ecos.fws.gov/ecp/species/9881.

Summary of Biological Status and Threats

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

Species Needs

    The Tennessee clubshell, Tennessee pigtoe, and Cumberland 
moccasinshell share similar habitat needs, preferring riffles, shoals, 
and high gradient streams with stable substrates composed predominantly 
of coarse sand, gravel, and cobble. Most often, the three species are 
found in habitat less than 3 feet (0.9 meter) deep, in small to medium-
sized rivers. Larger, more inflated shell types of Tennessee clubshell 
and Tennessee pigtoe inhabited large rivers prior to impoundment 
(Ortmann 1918, pp. 534-538, 550-555), but representation of these shell 
types has been lost, as both species, in addition to the Cumberland 
moccasinshell, require free-flowing streams and are not viable (do not 
successfully reproduce) in large impoundments, such as those along the 
mainstem Tennessee and Cumberland rivers. Known and likely fish hosts 
needed by each mussel species for reproduction are noted above (see 
General Mussel Biology).

Analysis Units

    For all three species, in our SSA, we used U.S. Geological Survey 
(USGS) 10-digit hydrologic unit codes (HUCs, or watersheds; see figures 
1-3, above) as analysis units for threats, current conditions, and 
future conditions. These analysis units were selected because they 
reflect relative differences in hydrologic conditions (e.g., separation 
by major impoundments), and they were at the finest spatial scale for 
which mussel survey data were available.

Threats

    We provide information regarding present and future influences, 
including both positive and negative, on the three

[[Page 57067]]

mussels' current and future viability, including large impoundments, 
urban development, energy development, and agriculture, which have 
altered natural flow regimes and/or diminished water and substrate 
quality (Factor A). The existing regulatory mechanisms (Factor D) have 
not been adequate to arrest the decline of the species. Additional 
threats, including nonnative competitors and pathogens (which may be 
responsible for enigmatic declines in some streams), likely have had 
negative effects on the three mussel species, as described in the SSA 
report and in a peer-reviewed publication on the SSA methodology 
(Fitzgerald et al. 2021, entire). These additional threats may 
negatively affect individuals of the species, but, unlike the primary 
threats, these additional threats do not affect the species' overall 
viability. Further, our analysis did not indicate that climate change 
is a primary threat to the three species. While the rangewide effects 
of climate change are likely to worsen in the future as droughts and 
storms are projected to become more intense, the primary threats (large 
impoundments, urban development, energy development, and agriculture) 
are the main driver of the three species' status currently and into the 
future.
    We used a regression model to identify the threats affecting the 
species. The model estimated the relative effects of a set of candidate 
predictor variables (threats) on the mussels' current conditions (see 
table 1, below). The threat variables retained for the regression 
analysis were those that best predicted mussel persistence at the 
rangewide scale. The analysis revealed the primary threats influencing 
current conditions of the three species are erosion and sedimentation 
from urban development and hydrologic alteration from large reservoirs 
and urban development. Mean runoff, another variable that reflects the 
impacts of erosion and sedimentation, was identified as a primary 
threat only to the Cumberland moccasinshell; its influence on the other 
two mussel species was not statistically significant.
    Several threats (candidate variables in the model) were considered 
as potential influences on current condition but were excluded from the 
regression analysis because they decreased the model's ability to 
detect the primary threats acting on the three mussel species rangewide 
(see table 1, below). However, some of the excluded threats negatively 
affect the three mussel species at smaller scales. In some watersheds 
in the upper Tennessee Basin and Cumberland Basin, energy development, 
which includes coal mining, natural gas, and oil extraction, has been 
identified as key threats to mussels that have reduced habitat (see 
``Energy Development--Coal, Natural Gas, and Oil,'' below).

Table 1--Summary of Major Threats Identified for Three Freshwater Mussel
 Species, Including Proxy Variables Considered and Variables Retained in
    the Final Model of Current Conditions of the Three Mussel Species
                          [Service 2020, p. 11]
------------------------------------------------------------------------
                                    Proxy variables       Variables in
            Threats                   considered           final model
------------------------------------------------------------------------
Hydrologic alteration.........  Reservoir surface area  Included.
                                Percentage developed    Included.
                                 land use.
                                Number and density of   Not included.
                                 dams.
Erosion and sedimentation.....  Coefficient of          Included.
                                 variation mean
                                 monthly precipitation.
                                Percentage developed    Included.
                                 land use.
                                Mean runoff...........  Included.
                                Density of agriculture  Included.
                                 (crops and
                                 pastureland).
                                Soil erodibility index  Not included.
Climate change................  Coefficient of          Included.
                                 variation mean
                                 monthly precipitation.
                                Mean monthly air        Not included.
                                 temperature.
Nutrient and chemical           Percentage developed    Included.
 pollution.                      land use.
                                Density of agriculture  Included.
                                 (crops and
                                 pastureland).
                                Percentage of mining    Not included.
                                 land use and number
                                 of mines.
                                Stream km impaired      Not included.
                                 (EPA 303(d) and TMDL
                                 lists \1\).
Nonnative competitors.........  No suitable proxy for   Not included.
                                 competitive effects
                                 identified.
------------------------------------------------------------------------
\1\ Section 303(d) of the Clean Water Act (33 U.S.C. 1251 et seq.)
  authorizes the Environmental Protection Agency (EPA) to assist States,
  Territories, and authorized Tribes in listing impaired waters and
  developing total maximum daily loads (TMDLs) for these waterbodies. A
  TMDL establishes the maximum amount of a pollutant allowed in a
  waterbody and serves as the starting point or planning tool for
  restoring water quality.

Large Impoundments
    Our analysis identified large impoundments (indicated by reservoir 
surface area) as a rangewide threat to the three mussel species. The 
Tennessee Valley Authority operates 31 large dams in the Tennessee 
River system and one large dam (Great Falls Dam) in the Cumberland 
system (TVA Recreation Map website, 2023) and the U.S. Army Corps of 
Engineers operates 10 large dams in the Cumberland system (USACE 
Nashville District website, 2023). The effects of dams on aquatic 
habitats and freshwater mussels are well-documented (Watters 2000, p. 
261), and extinction and extirpations of North American freshwater 
mussels can be traced to impoundment and inundation of riffle habitats 
in all major river basins of the central and eastern United States 
(Haag 2009, p. 107).
    Dams disrupt population connectivity and alter water quality. After 
a dam has been constructed, upstream the channel becomes deeper, flow 
decreases dramatically, and fine sediments accumulate on the channel 
bottom, which eliminates shoal and riffle habitats needed by the three 
mussel species, as well as many others, and their host fishes. 
Downstream of dams, natural flow regimes are disrupted by alternating 
low flow releases and pulses of scouring flows (Hardison and Layzer 
2001, p. 79), reduced water temperatures, reduced dissolved oxygen, and 
changes in fish assemblages. Mussels may survive in cold tailwaters but 
may not be able to reproduce, as was shown for native washboard mussels 
(Megalonaias nervosa) in the mainstem Cumberland River (Heinricher and 
Layzer 1999, entire). In a Cumberland River tributary, Caney Fork, the 
extirpation of several mussel species, including Cumberland 
moccasinshell, was attributed mainly to cold tailwater temperatures 
from Center Hill Dam (completed in 1948) and

[[Page 57068]]

alteration of channel morphology from peaking flows, and no live 
mussels were found within 7.5 mi (12 km) of the dam outfall (Layzer et 
al. 1993, pp. 69-70).
Developed Land Use/Urbanization
    For all three mussel species, development and urbanization 
contribute to habitat degradation and loss. Freshwater mussel 
populations may experience reduced abundance, species richness, 
reproduction, growth, and survival stemming from the impacts of 
urbanization on water and habitat quality (Diamond and Serveiss 2001, 
p. 4716; Gangloff et al. 2009, p. 198; Cao et al. 2013, pp. 1212-1214; 
Gillis et al. 2017, pp. 674-679). The threats analysis in our SSA found 
the estimated probability of extirpation for all three species 
approaches 100 percent when developed land area is between 9 and 15 
percent of the total land area in a watershed (Service 2020, p. 61). 
The term ``development'' refers to urbanization of the landscape, 
including (but not limited to) land conversion for residential, 
commercial, and industrial uses and the accompanying infrastructure. 
Urbanization effects may include alterations to water quality, water 
quantity, and instream and streamside habitat (Ren et al. 2003, p. 649; 
Wilson 2015, p. 424). The effects on habitat also include variability 
in streamflow, typically increasing the extent and volume of water 
entering a stream after a storm and decreasing the time it takes for 
the water to travel over the land before entering the stream (Giddings 
et al. 2009, p. 1).
    In urbanized environments, storm drains deliver large volumes of 
water to streams much faster than would naturally occur, often 
resulting in flooding and bank erosion that reshape the channel and 
cause substrate instability. Increased, high-velocity discharges can 
cause species living in streams (including mussels) to become stressed, 
displaced, or killed by fast-moving water and the debris and sediment 
carried in it. Once floodwaters recede, displaced individuals may be 
left stranded out of the water, and fine sediments transported to the 
stream settle on coarser substrates, which may damage or destroy areas 
of mussel habitat. During storm events, contaminants in urbanized 
environments (e.g., gasoline, oil drips, fertilizers) accumulated on 
impervious surfaces may be washed directly into streams.
Energy Development--Coal, Natural Gas, and Oil
    Extraction of coal, natural gas, and (to a lesser extent) oil is 
common in the Cumberland and Upper Tennessee River basins and has been 
associated with mussel declines in several watersheds (Layzer and 
Anderson 1992, entire; Warren and Haag 2005, entire; Johnson et al. 
2014, p. 890; TDEC 2014, p. 62; Zipper et al. 2016, pp. 612-613; 
Ahlstedt et al. 2016, p. 13). Examples of energy development impacts in 
the range of the three mussels include high levels of copper, 
manganese, and zinc, metals that can be toxic to freshwater mussels, 
found in sediment samples from both the Clinch and Powell Rivers. Both 
rivers receive runoff from active, reclaimed, and abandoned coal mine 
sites. In Cumberland Basin streams, including Buck Creek, Horse Lick 
Creek, Little South Fork, and Rockcastle River, there was a clear 
correlation between surface mines, increased metal concentrations 
downstream, and the extirpation of some mussel species (Layzer and 
Anderson 1992, pp. 91-96). In the upper Powell River, Virginia, coal 
mining has almost eliminated the mussel fauna; sediment pore water from 
the riverbed contains levels of contaminants potentially toxic to 
mussels, particularly selenium and copper (Timpano et al. 2023, p. 13).
    Natural gas and oil extraction is a threat to freshwater mussels in 
the Upper Tennessee Basin and Cumberland Basin. In addition to the 
general impacts of erosion and sedimentation from forest clearing for 
access roads and installing drill pads, spills from (brine) disposal 
ponds at gas wells or end-of-pipe discharges from brine treatment 
facilities can reduce freshwater mussel abundance and diversity, as 
well as increase mortality. These effects have been observed in the 
Allegheny River (Patnode et al. 2015, p. 55), a watershed outside the 
range of the three mussel species, but within the Ohio Basin, which 
contains the Tennessee River and Cumberland River.
Agriculture
    Agricultural activities are common throughout the range of the 
three mussel species and have impacted watersheds in the species' 
historical and current ranges. The advent of intensive row crop 
agriculture is a potential factor in freshwater mussel decline and 
species extirpation in the eastern United States (Peacock et al. 2005, 
p. 550). Nutrient enrichment from fertilized crops and livestock is a 
threat commonly associated with negative effects on aquatic biota and 
can increase ammonia concentrations, to which freshwater mussels are 
particularly sensitive. In addition, agricultural pesticides, including 
herbicides, fungicides, insecticides, and their surfactants and 
adjuvants, are highly toxic to juvenile and adult freshwater mussels 
(Bringolf et al. 2007, p. 2,092). Concentrations of these contaminants 
from fields or pastures may be at levels that can affect an entire 
population, especially given the highly fragmented distributions of the 
three mussel species.
    Agricultural land use has been associated with decreased freshwater 
mussel diversity, growth, and survival in North American streams. A 
temporal analysis of freshwater mussel populations in Iowa streams 
showed declines in mussel species richness, and local extirpations 
corresponded with agricultural intensity and forest clearing of the 
riparian zone (Poole and Downing 2004, pp. 121-124). In those Iowa 
streams, the segments with the highest substrate diversity exhibited 
the lowest declines in species richness, indicating homogenization of 
substrates from sedimentation is a freshwater mussel stressor. Further, 
species richness increased or was unchanged where agriculture was less 
than 25 percent of the land use. Another study, in Minnesota streams, 
revealed decreases in mussel abundance and richness corresponding with 
increases in agricultural land use (Hornbach et al. 2019, p. 1,833). In 
Kentucky, streams in proximity to row crop agriculture were associated 
with higher values of contaminants (pesticides and fertilizers), and 
growth of caged mussels in those streams was low in comparison with 
most other streams, where row crops were a minor land use (Haag et al. 
2019, pp. 761-763). One of the streams in the study with high row crop 
land use was the Red River, in the historical range of the Cumberland 
moccasinshell and with one current low-condition population of the 
Tennessee clubshell. The abnormally low growth rates observed in the 
streams in proximity to high row crop land use usually presage early 
mortality observed in mussel hatchery settings (Haag et al. 2019, p. 
765).
    Agencies such as the U.S. Department of Agriculture's Natural 
Resources Conservation Service, along with State soil and water 
conservation districts, provide technical and financial assistance to 
farmers and private landowners. Additionally, county resource 
development councils and university agricultural extension services 
disseminate information on the importance of minimizing land use 
impacts, specifically the effects of agricultural practices, on aquatic 
resources. These programs help identify opportunities for conservation 
through projects such as exclusion fencing and alternate water supply 
sources, which

[[Page 57069]]

help decrease nutrient inputs and keep livestock off stream banks and 
shorelines, thus reducing erosion. However, the overall effectiveness 
of these programs over a large scale is unknown given the three mussel 
species' wide distribution and varying agricultural intensities.
    Effects of the agricultural activities within the ranges of the 
three mussel species, including diminishment of water quality and 
habitat deterioration, are not often detected until after the 
sedimentation and/or pesticide and herbicide inputs occur. In summary, 
many effects of agricultural practices are pervasive across the ranges 
of the three mussel species and are a factor in their historical 
decline and localized extirpations.
Contaminants
    Three of the land uses identified as threats to the three mussel 
species (urban development, energy development, and agriculture) 
contribute contaminants to stream habitats, which can degrade water and 
substrate quality and adversely impact individuals and populations. 
Although chemical spills and other point sources of contaminants may 
directly result in mussel mortality, widespread decreases in density 
and diversity may result in part from the subtle, pervasive effects of 
chronic, low-level contamination (Naimo 1995, p. 354).
    The effects of contaminants such as metals, chlorine, and ammonia 
on juvenile mussels are profound (Augspurger et al. 2003, p. 2,571; 
Bartsch et al. 2003, p. 2,566). Among 69 aquatic organisms, the EPA 
reported freshwater mussels (from tests on juveniles and glochidia) 
were the taxonomic group most sensitive to ammonia (U.S. EPA 2013, pp. 
24-27), which is a common contaminant in sewage plant discharges and 
agricultural runoff. Juvenile mussels may readily ingest contaminants 
adsorbed to sediment particles (Newton and Cope 2007, p. 276), and, 
unlike adults, they feed in sediment pore water rather than on surface 
water (Yeager et al. 1994, p. 221). Unionized ammonia in pore water was 
clearly associated with recruitment failure in populations of eastern 
elliptio (Elliptio complanata) mussels in the wild and was at 
concentrations far below those found to be toxic in laboratory 
experiments (Strayer and Malcom 2012, pp. 1,787-1,788).
    Mussel glochidia are sensitive to some toxicants (Goudreau et al. 
1993, p. 221; Jacobson et al. 1997, p. 2,386; Valenti et al. 2005, p. 
1,243). Even at low levels, certain heavy metals may inhibit glochidial 
attachment to fish hosts. Contaminants have been shown to affect mussel 
glochidia on the Clinch River (Goudreau et al. 1993, p. 221; Jacobson 
et al. 1997, p. 2,386; Valenti et al. 2005, p. 1,243), which harbors 
some of the best condition populations of the three species, 
particularly the Cumberland moccasinshell.
    Cadmium, chromium, copper, mercury, and zinc can negatively affect 
biological processes of all mussel life stages (Havlik and Marking 
1987, pp. 4-9; Naimo 1995, p. 355; Jacobson et al. 1997, p. 2,389; 
Valenti et al. 2005, p. 1,243). Chronic mercury contamination from a 
chemical plant on the North Fork Holston River destroyed a diverse 
mussel fauna downstream of Saltville, Virginia (Brown et al. 2005, p. 
1,459). Copper and zinc contamination originating from wastewater 
discharges at a coal-fired electric power plant is one of the sources 
of mussel declines in a reach of the Clinch River (Zipper et al. 2014, 
p. 9). Despite localized improvements since these rivers initially were 
contaminated, metals have remained in sediments, affecting recruitment 
and densities of the mussel fauna for decades thereafter (Price et al. 
2014, p. 12; Zipper et al. 2014, p. 9).
Threats Summary
    In summary, the primary threats have curtailed the habitat and 
range of the Tennessee clubshell, Tennessee pigtoe, and Cumberland 
moccasinshell, via flow alterations caused by large impoundments and 
diminishment of water and substrate quality caused by various land 
development activities. These threats, which result in both 
contamination and the physical disruption of surface waters and 
substrates, are the source of negative impacts to freshwater mussel 
fauna, including the Tennessee clubshell, Tennessee pigtoe, and 
Cumberland moccasinshell.

Current Conditions

    The current resiliency of the Tennessee clubshell, Tennessee 
pigtoe, and Cumberland moccasinshell was analyzed using demographic and 
spatial distribution criteria (see table 2, below). Data for the 
criteria are from quantitative and qualitative mussel surveys reported 
in peer-reviewed literature, agency reports, and museum databases 
(Service 2020, p. 8). Resiliency was classified as low, medium, or high 
in the 10-digit HUC watersheds in each mussel species' historical 
range. Demographic criteria consisted of categories of abundance or 
density, and evidence of recent recruitment (inferred from the presence 
of individuals less than or equal to 30 mm in shell length). 
Distribution criteria were based on stream distance occupied within a 
watershed.

              Table 2--Criteria for Classifying Current Conditions of Populations Within Watersheds
                                              [Service 2020, p. 10]
----------------------------------------------------------------------------------------------------------------
                                         Demographic criteria
          Condition           ----------------------------------------- Distribution criteria    Probability of
                                 Abundance \1\        Reproduction                              persistence \2\
----------------------------------------------------------------------------------------------------------------
High.........................  Abundant........  Evidence of            Occurs in more than                >0.75
                                                  reproduction.          50 river km.
                               Common..........  Increasing population
                                                  trend or evidence of
                                                  reproduction.
Medium.......................  Abundant........  Decreasing population  Occurs in 10-50 river          0.25-0.75
                                                  trend or no evidence   km.
                                                  of reproduction.
                               Common..........  No information
                                                  available.
                               Rare............  Evidence of recent
                                                  reproduction.
Low..........................  Common..........  Decreasing trend or    Occurs in less than                <0.25
                                                  no evidence of         10 river km.
                                                  reproduction.
                               Rare............  Decreasing trend or
                                                  no evidence of
                                                  reproduction.
                              -----------------------------------------
                               Presence-absence data only.
                              -----------------------------------------

[[Page 57070]]

 
Unknown......................  Historical records of occurrence in      Subwatershed (HUC10)
                                watershed with no surveys in past 30     lacking site-
                                years.                                   specific surveys in
                                                                         watershed (HUC8) of
                                                                         known occurrence.
                              -----------------------------------------
Extirpated...................  No live or fresh dead individuals        No areas known to be
                                collected in surveys within the past     currently occupied
                                30 years.                                within watershed.
----------------------------------------------------------------------------------------------------------------
\1\ In this column, abundant is defined as more than 500 individuals reported or densities greater than 0.70 per
  square meter (m\2\); common is defined as 100-500 individuals reported or densities between 0.10-0.70/m\2\;
  and rare is defined as fewer than 100 individuals reported or densities fewer than 0.10/m\2\.
\2\ Probability of persistence represents expected risk of extirpation over 30 years (roughly 3 generations),
  with numeric estimates selected based on best professional judgment of freshwater mussel experts.

    Mussel records were considered current if they included detection 
of live individuals or fresh dead shells (with soft tissue attached) 
since 1988. Watersheds containing only records before 1988 were 
considered extirpated if recent surveys had not encountered live 
individuals or no suitable habitat was available (e.g., large 
impoundments), and unknown if no recent surveys (since 1988) were 
conducted. This approach represents an underestimate of decline, as 
only watersheds with confirmed records were considered historically 
occupied. Because early surveys did not always record exact localities 
and many watersheds faced hydrologic alterations prior to comprehensive 
sampling, actual historical ranges (still confined to the Cumberland 
and/or Tennessee Basin) were likely greater than those represented in 
figure 2 of the SSA report (Service 2020, p. 13). In addition, sampling 
has not occurred in a standardized manner, and many watersheds with 
unknown current conditions may reflect experts' opinions that these 
regions are unlikely to support viable populations (i.e., sample 
selection bias). This suggests that upper values of estimated range 
reductions (74 percent, 76 percent, and 62 percent for the Cumberland 
moccasinshell, Tennessee clubshell, and Tennessee pigtoe, respectively) 
may better represent current conditions of these species (see table 3, 
below). Early surveys of freshwater mussels often recorded qualitative 
descriptions of abundance (e.g., rare, common, widespread) that make 
direct comparison of current abundance estimates impossible; however, 
it is widely accepted in the literature that dramatic reductions from 
historical abundance have occurred throughout the ranges of these 
species.
    In the absence of sufficient genetic data to confirm spatial 
population structure, we treated each watershed as a population for our 
analyses of species conditions. Watersheds were nested within two major 
units of representation, the Cumberland River basin and the Tennessee 
River basin. For each of the three species, redundancy was 
characterized by the number of populations, and, in our analysis, range 
loss incorporates redundancy as the portion of watersheds where the 
species is extirpated (see table 3, below). Although populations in low 
condition contribute to redundancy values, they have minimal influence 
on population resiliency and species representation. Low-condition 
populations are not, or are barely, recruiting individuals to found new 
generations and, therefore, are functionally extirpated.

                  Table 3--Current Resiliency of All Watersheds (Populations), and Range Loss (Percent of Watersheds Where Extirpated)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        Current resiliency
                         Species                         --------------------------------------------------------------------------------   Range loss
                                                            Extirpated          Low           Medium           High           Unknown        (percent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Tennessee clubshell.....................................              83              28               4               3              29           58-76
Tennessee pigtoe........................................              51              32               8               3              20           42-62
Cumberland moccasinshell................................              87              22               3               9              29           56-74
--------------------------------------------------------------------------------------------------------------------------------------------------------

Tennessee Clubshell--Current Conditions
    The Tennessee clubshell historically occurred throughout the 
Tennessee and Cumberland River basins. Currently, it occupies 35 to 64 
watersheds, compared to 147 historically, reflecting a range reduction 
of 58 to 76 percent. Most extant populations of the species are 
classified as low condition (28), with only three populations 
classified as high condition and four populations classified as medium 
condition, indicating species condition is currently low (see table 3, 
above). Rangewide, there are three redundant populations with high 
resiliency, which are likely to withstand the effects of stochastic 
events, and five redundant populations with medium resiliency, which 
may withstand the effects of a stochastic event. The 28 low-condition 
(low resiliency) populations have little capacity to withstand the 
effects of a stochastic event and do not contribute to species 
redundancy or the species' capacity for withstanding catastrophic 
events. While the Tennessee clubshell persists in the Tennessee River 
basin, it is on the verge of extirpation from the entire Cumberland 
River basin, with only 5 low-condition populations (low resiliency) and 
16 extirpated populations. Extirpation of the species from this basin 
would result in a 50 percent loss in representation, as the Tennessee 
clubshell would be lost from one of the two major ecological settings 
(representation units) in its range.

[[Page 57071]]

Representation has been further diminished by reductions in 
connectivity between mainstem and tributary streams, which contribute 
to reduced size and genetic isolation of Tennessee clubshell 
populations.
Tennessee Pigtoe--Current Conditions
    The Tennessee pigtoe was once a common species throughout the 
Tennessee Basin. Currently, it occupies 43 to 63 watersheds, compared 
to 114 historically, reflecting a range reduction of 42 to 62 percent. 
Most extant populations of the species are classified as low condition 
(32), with only three populations classified as high condition and 
eight populations classified as medium condition, indicating species 
condition is currently low (see table 3, above). Rangewide, there are 
three redundant populations with high resiliency, which are likely to 
withstand the effects of stochastic events, and eight redundant 
populations with medium resiliency, which may withstand the effects of 
a stochastic event. The 32 low-condition (low resiliency) populations 
have little capacity to withstand the effects of a stochastic event and 
do not contribute to species redundancy or the species' capacity for 
withstanding catastrophic events. Representation of the Tennessee 
pigtoe has declined, as populations in the mainstem Tennessee River are 
extirpated and the connectivity between tributaries is disrupted by 
impoundments, which has diminished population interaction necessary for 
maintenance of genetic diversity.
Cumberland Moccasinshell--Current Conditions
    The Cumberland moccasinshell historically occurred throughout the 
Tennessee and Cumberland River basins. Currently it occupies 34 to 63 
watersheds, compared to 150 historically, reflecting a range reduction 
of 56 to 74 percent. Most extant populations of the species are 
classified as low condition (22), with nine populations classified as 
high condition and three populations classified as medium condition, 
indicating species condition is currently low (see table 3, above). 
With nine populations in high condition and two populations in medium 
condition in the Tennessee Basin, redundancy in the basin may buffer 
against stochastic events. However, these populations are concentrated 
in Upper Tennessee Basin tributaries, mainly the Clinch-Powell 
watershed, with seven high condition populations, and one high 
condition population in the Holston watershed. The Duck River 
watershed, in the lower Tennessee Basin, has one high-condition and two 
medium-condition populations. The low-condition populations in the rest 
of the Tennessee Basin lack resiliency and have little capacity to 
withstand effects of environmental stochasticity. Because there are no 
populations with high resiliency, and only one population with medium 
resiliency in the Cumberland basin ecological setting, and smaller-
scale ecological settings outside the Upper Tennessee and Duck basins 
only contain populations with low resiliency, Cumberland moccasinshell 
representation, or its potential for adapting to environmental change, 
is diminished.

Current Risk Profiles

    We used the model parameters estimated in the current conditions 
analysis (i.e., the relative effects of each stressor) to model the 
probability that a watershed would be classified as extirpated, low, 
medium, or high based on historical land-use and climate patterns. 
These probabilities discussed in the ``Future Conditions'' section of 
our SSA report (Service 2020, pp. 16-20) represent the species' present 
(or baseline; i.e., current) risk profile with no additional climate or 
land-use changes. The baseline modeling, based on threats alone, 
measures the present extirpation risk to all populations regardless of 
their current condition. For example, there may be populations that 
have a comparatively high demographic and distributional condition, but 
due to significant stressors that are already acting on the population, 
such as large impoundments and isolation, they also have a high 
probability of extirpation. Additionally, because low-condition 
populations contain few individuals or display little evidence of 
recruitment), they have an inherently high risk of extirpation within 
several generations. Importantly, these baseline estimates are not 
impacted by uncertainty in future climate or land-use scenarios because 
they derive from currently observed patterns across the landscape. 
These baseline probabilities are assumed valid over the next 10 years. 
Therefore, we used the current or baseline probability to assess the 
current risk of extirpation or low condition to each of the three 
mussel species (see table 4, below).
    The current risk of being classified as extirpated or low condition 
for all three species was similar. For Tennessee clubshell, the average 
current risk of being classified as extirpated or low condition is 0.71 
and 0.23, respectively. In addition, nearly all populations of 
Tennessee clubshell may be at high risk of being classified as 
extirpated or low condition due to current land use. For Tennessee 
pigtoe, the average current risk of being classified as extirpated or 
low condition is 0.54 and 0.34, respectively. In addition, all 
populations of Tennessee pigtoe were more likely than not to be 
classified as extirpated or low condition based on current patterns of 
land use within watersheds. For Cumberland moccasinshell, the average 
current risk of being classified as extirpated or low condition is 0.72 
and 0.16, respectively. The current risk of being classified as 
extirpated or low condition was similarly high for Cumberland 
moccasinshell populations in the lower Tennessee and throughout the 
Cumberland Basin as described for Tennessee pigtoe; however, the upper 
Tennessee Basin currently contains eight populations classified as high 
condition that may have lower risk of becoming extirpated or low 
condition populations compared to other regions.

     Table 4--Average Current Probability (Baseline or Current Risk Profile) of Species Condition Across All
                                        Watersheds Given Current Threats
----------------------------------------------------------------------------------------------------------------
                     Species                        Extirpated          Low           Medium           High
----------------------------------------------------------------------------------------------------------------
Tennessee Clubshell.............................            0.71            0.23            0.04            0.03
Tennessee Pigtoe................................            0.54            0.34            0.06            0.05
Cumberland Moccasinshell........................            0.72            0.16            0.04            0.08
----------------------------------------------------------------------------------------------------------------

Future Conditions

    Because we determined that the current condition of the Tennessee 
clubshell, Tennessee pigtoe, and Cumberland moccasinshell is consistent 
with an endangered species (see Determination of Status for the Three 
Mussel Species, below), we are not presenting the results of the future

[[Page 57072]]

scenarios in this proposed rule. However, above, we present the 
baseline or current risk profile results as these were used in the 
determination of the three species' status. Please refer to the SSA 
report (Service 2020, pp. 16-21) for the full analysis of future 
scenarios.
    We note that, by using the SSA framework to guide our analysis of 
the scientific information documented in the SSA report, we have not 
only analyzed individual effects on the three species, but we have also 
analyzed their potential cumulative effects. We incorporate the 
cumulative effects into our SSA analysis when we characterize the 
current and future condition of the three species. To assess the 
current and future condition of the three species, we undertake an 
iterative analysis that encompasses and incorporates the threats 
individually and then accumulates and evaluates the effects of all the 
relevant factors that may be influencing the species, including threats 
and conservation efforts. For each of the three species, 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.

Conservation Efforts and Regulatory Mechanisms

    Existing conservation measures directly benefiting the three mussel 
species are limited. Five percent or less of the currently occupied 
area for all three species is within protected areas managed for 
biodiversity conservation (Service 2020, pp. 27-29). While the percent 
of areas receiving some level of protection is slightly greater (15 
percent or less), many of these areas are subject to mining and other 
extractive uses detrimental to freshwater mussels. Compared to 
currently extant populations of the three species, the percentage of 
protected area is similar for extirpated populations, suggesting the 
levels of protection observed are not adequate to prevent local 
extirpations.
    Reintroductions have been attempted for at least three populations 
of Cumberland moccasinshell using individuals translocated from the 
Clinch River at Kyles Ford, Tennessee, to other rivers in the State. 
Between 2010 and 2015, 1,100 individuals were stocked in the Emory 
River, and 3,539 individuals were stocked in the Nolichucky River 
(Phipps et al. 2018, pp. 27-41). Populations of the Cumberland 
moccasinshell in both rivers are currently in low condition and do not 
appear to be reproducing based on 2016 surveys. An additional 800 
individuals were stocked in the Hiwassee River in 2012 (Phipps et al. 
2018, pp. 26-27), but reintroduction efforts were not successful, and 
this population is currently considered extirpated. It is possible that 
cold-water discharges from Apalachia Dam, which is operated as a 
peaking hydropower facility, have reduced the reintroduction potential 
of mussel species in the Hiwassee River. Unnatural thermal regimes 
continue to affect populations of Tennessee clubshell in the Hiwassee 
River and freshwater mussels below other hydropower dams in the 
Tennessee River basin (Layzer and Scott 2006, p. 488).
    States vary in level of protection provided to freshwater mussels 
in general. The State of Virginia has statutory protection for 
freshwater mussels. State wildlife management agencies in Alabama, 
Tennessee, North Carolina, and Kentucky have protective regulatory 
measures prohibiting the take or possession of freshwater mussels 
without a scientific collector's permit. Freshwater mussel species are 
only protected in Georgia if they are listed under the Act. 
Accordingly, they currently may be taken with a fishing license or 
commercial fishing license. A variety of additional ``designations'' or 
status descriptions are assigned to the three species within States of 
occurrence; however, these do not indicate State statutory protections, 
nor are they associated with habitat or restoration priorities.

Determination of Status for the Three Mussel Species

    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 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

    After evaluating threats to the species and assessing the 
cumulative effects of the threats under the Act's section 4(a)(1) 
factors, we found that the three mussel species have declined 
significantly in distribution and abundance. The primary broadscale 
threats, development (as urbanization) and large impoundments, and more 
localized threats, including energy development and agriculture, have 
reduced available habitat, curtailing the range of the three species 
(Factor A). All three species have experienced substantial reductions 
in their current distributions compared to historical ranges.
    Our SSA modeled the current probability (i.e., baseline or current 
risk profile) that the species' status within various watersheds would 
be extirpated, low, medium, or high (see table 4, above) based on 
historical land-use and climate patterns, which account for the 
rangewide primary threats as discussed above. Together, the model 
(baseline or current risk profile) and current population conditions 
analysis (which is based on observations in the wild and current 
threats) informed our determination as to whether each species is in 
danger of extinction throughout all or a significant portion of its 
range (i.e., whether each species meets the definition of an endangered 
species under the Act). Our determinations for each species are 
discussed below.

Tennessee Clubshell--Status Throughout All of Its Range

    The Tennessee clubshell historically occurred throughout the 
Tennessee and Cumberland River basins. Most extant populations of the 
Tennessee clubshell are in low condition (have low resiliency) and 
exhibit little to no reproduction. Recruitment of new generations to 
the low-condition populations is very unlikely, and, as such, they are 
functionally extirpated, with little resistance to stochastic events, 
and they are unlikely to recover under the chronic stresses of current 
and projected threats. The three high-condition populations are 
restricted to the upper Tennessee River basin, in the Clinch River (two 
watersheds) and Hiwassee River (one watershed). In the Cumberland Basin 
representation unit, 5 populations are in low condition, and 16 are 
extirpated. As discussed above, while the Tennessee clubshell persists 
in the Tennessee River basin, it is on the verge of extirpation from 
the entire

[[Page 57073]]

Cumberland River basin, with only 5 low-condition populations and 16 
extirpated populations. Extirpation of the species from this basin 
would result in a 50 percent loss in representation. Representation has 
been further diminished by reductions in connectivity between mainstem 
and tributary streams, which contribute to reduced size and genetic 
isolation of Tennessee clubshell populations.
    Because species viability is bolstered by having a broad spatial 
distribution across ecological settings (representation) and a 
sufficient number of resilient populations (redundancy), the 
restriction of few resilient populations to one region, in comparison 
to the broader distribution of populations historically, indicates 
species viability is currently low. In addition, the average current 
risk of extirpation (0.71) or low condition (0.23) across all 
watersheds for the Tennessee clubshell is high. Given the preponderance 
of low condition populations that are likely functionally extirpated 
throughout the species' range and the extent of urban development and 
large impoundments throughout the range, as well as more localized 
threats, including energy development and agriculture, the Tennessee 
clubshell is in danger of extinction throughout its range. Unlike a 
threatened species, which is likely to become an endangered species 
within the foreseeable future throughout all or a significant portion 
of its range, the Tennessee clubshell is in danger of extinction 
throughout its range now, owing to the low condition of most 
populations and their current high risk of extirpation resulting from 
current threats. Thus, after assessing the best available information, 
we determine that Tennessee clubshell is in danger of extinction 
throughout all of its range.

Tennessee Clubshell--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 Tennessee clubshell 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 Tennessee clubshell 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) (Everson), which vacated the provision of the 
Final Policy on Interpretation of the Phrase ``Significant Portion of 
Its Range'' in the Endangered Species Act's Definitions of ``Endangered 
Species'' and ``Threatened Species'' (Final Policy; 79 FR 37578, July 
1, 2014) providing that if the Service determines that a species is 
threatened throughout all of its range, the Service will not analyze 
whether the species is endangered in a significant portion of its 
range.

Determination of Status for the Tennessee Clubshell

    Our review of the best available scientific and commercial 
information indicates that the Tennessee clubshell meets the Act's 
definition of an endangered species. Therefore, we propose to list the 
Tennessee clubshell as an endangered species in accordance with 
sections 3(6) and 4(a)(1) of the Act.

Tennessee Pigtoe--Status Throughout All of Its Range

    Once a common species in the Tennessee Basin, most extant 
populations of the Tennessee pigtoe are in low condition (have low 
resiliency) and exhibit little to no reproduction. Recruitment of new 
generations to the low-condition populations is very unlikely, and, as 
such, they are functionally extirpated, with little resistance to 
stochastic events, and they are unlikely to recover under the chronic 
stresses of current and projected threats. Two of the three high-
condition populations are in the upper part of the basin, in a Clinch 
River subwatershed and one of the river's tributaries, Copper Creek. 
The other high-condition population is in the lower Tennessee system, 
in the Duck River basin. Eight populations are in medium condition and 
distributed among lower, middle, and upper Tennessee Basin watersheds.
    The Tennessee pigtoe may have sufficiently resilient populations 
(redundancy) spread over a large enough area to withstand a 
catastrophic event due to the occurrence in eight watersheds by either 
a high-condition or medium-condition population (three high-condition 
and eight medium-condition). However, populations in the mainstem 
Tennessee River, where the phenotype with a larger, more inflated shell 
only occurred, are extirpated. In addition, numerous large impoundments 
on the mainstem Tennessee and several of its tributaries prevent gene 
flow between populations, which is necessary for maintaining 
representation. The average current risk of extirpation across all 
watersheds for the Tennessee pigtoe is high (0.54) based on current 
patterns of land use within the watersheds. Therefore, the 11 
populations in high and medium condition may be at high risk of 
becoming extirpated or low condition in the future given current land 
use and population trajectories. While the reduction in range (42 to 62 
percent) appears slightly smaller for the Tennessee pigtoe when 
compared to the Cumberland moccasinshell and the Tennessee clubshell, 
this may reflect the Tennessee pigtoe's endemism to the Tennessee Basin 
and naturally smaller distribution rather than differences in the 
species' response to major stressors. Given the extent of urban 
development and large impoundments, and more localized but widespread 
threats of energy development and agriculture, most populations of the 
Tennessee pigtoe are in low condition such that they are at high risk 
of extirpation. Unlike a threatened species, which is likely to become 
an endangered species within the foreseeable future throughout all or a 
significant portion of its range, the Tennessee pigtoe is in danger of 
extinction throughout its range now, owing to the low condition of most 
populations and their current high risk of extirpation resulting from 
current threats. Thus, after assessing the best available information, 
we determine that the Tennessee pigtoe is in danger of extinction 
throughout all of its range.

Tennessee Pigtoe--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 Tennessee pigtoe 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 Tennessee pigtoe warrants listing as endangered throughout all of 
its range, our determination does not conflict with the decision in 
Everson, which vacated the provision of the Final Policy (79 FR 37578; 
July 1, 2014) providing that if the Service determines that a species 
is threatened throughout all of its range, the Service will not analyze 
whether the species is endangered in a significant portion of its 
range.

Determination of Status for the Tennessee Pigtoe

    Our review of the best available scientific and commercial 
information indicates that the Tennessee pigtoe meets the Act's 
definition of an endangered species. Therefore, we propose to list the 
Tennessee pigtoe as

[[Page 57074]]

an endangered species in accordance with sections 3(6) and 4(a)(1) of 
the Act.

Cumberland Moccasinshell--Status Throughout All of Its Range

    Historically occurring throughout the Tennessee and Cumberland 
Basins, most extant populations of the Cumberland moccasinshell are in 
low condition (have low resiliency) and exhibit little to no 
reproduction. Recruitment of new generations to the low-condition 
populations is very unlikely, and, as such, they are functionally 
extirpated, with little resistance to stochastic events, and they are 
unlikely to recover under the chronic stresses of current and projected 
threats. Nine populations are in high condition, with seven occupying 
the Clinch River drainage and one occupying a watershed in the North 
Fork Holston River drainage, both in the Upper Tennessee Basin. One 
high-condition population and two medium-condition populations are in 
the Duck River watershed. In the Cumberland Basin representation unit, 
1 population is in medium condition, 7 are in low condition, and 20 are 
extirpated. The average current risk of extirpation across all 
watersheds for the Cumberland moccasinshell is high (0.72).
    Containing eight of the nine high-condition populations rangewide, 
the Upper Tennessee Basin is a stronghold for the species. However, in 
the Upper Tennessee, there is uncertainty around population condition, 
for which mean risk of extirpation or low-condition population ranges 
from 0.5 to 0.8. The stronghold status of the Upper Tennessee Basin and 
the presence of one high-condition and two medium-condition populations 
in the Lower Tennessee Basin's Duck River, and another medium-condition 
population in the Cumberland Basin, indicate the species has some 
capacity to withstand a catastrophic event, although species redundancy 
is greatly reduced from historical levels.
    Although currently nine populations are in high condition, they are 
isolated by large impoundments and the hundreds of river miles between 
the three river systems where they occur. This isolation prohibits 
genetic exchange between populations, which is essential to maintaining 
adaptive capacity (representation); therefore, the average risk of 
extirpation or low condition is high (greater than 0.5) for most of the 
high-condition populations. Additionally, the level of current 
rangewide threats to the species, which have contributed to documented 
extirpation from 87 of 150 watersheds, is projected to remain 
relatively constant, suggesting population trajectories are unlikely to 
change. Considering watersheds of unknown condition are likely 
extirpated and instead are classified as ``unknown'' due to being 
excluded from surveys because of poor habitat quality, the number of 
extirpations is likely closer to 106 of the 150 watersheds. The current 
level and extent of threats has resulted in a low-condition or 
extirpated state for most populations of the Cumberland moccasinshell, 
such that these populations are at a high risk of extirpation. Unlike a 
threatened species, which is likely to become an endangered species 
within the foreseeable future throughout all or a significant portion 
of its range, the Cumberland moccasinshell is in danger of extinction 
throughout its range now, owing to the low condition of most 
populations and their current high risk of extirpation resulting from 
current threats. Thus, after assessing the best available information, 
we determine that the Cumberland moccasinshell is in danger of 
extinction throughout all of its range.

Cumberland Moccasinshell--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 Cumberland moccasinshell 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 Cumberland moccasinshell warrants listing as endangered 
throughout all of its range, our determination does not conflict with 
the decision in Everson, which vacated the provision of the Final 
Policy (79 FR 37578; July 1, 2014) providing that if the Service 
determines that a species is threatened throughout all of its range, 
the Service will not analyze whether the species is endangered in a 
significant portion of its range.

Determination of Status for the Cumberland Moccasinshell

    Our review of the best available scientific and commercial 
information indicates that the Cumberland moccasinshell meets the Act's 
definition of an endangered species. Therefore, we propose to list the 
Cumberland moccasinshell 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, 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.
    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

[[Page 57075]]

substantive information becomes available. For each of the three 
species, the recovery outlines, draft recovery plans, final recovery 
plans, and any revisions will be available on our website (https://ecos.fws.gov/ecp/species/3254; https://ecos.fws.gov/ecp/species/9887; 
and https://ecos.fws.gov/ecp/species/9881) or from our Asheville 
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT) 
as they are completed.
    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 these species are listed, funding for recovery actions will 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 States of Alabama, Georgia, 
Kentucky, North Carolina, Tennessee, and Virginia would be eligible for 
Federal funds to implement management actions that promote the 
protection or recovery of the Tennessee clubshell, Tennessee pigtoe, 
and Cumberland moccasinshell. Information on our grant programs that 
are available to aid species recovery can be found at: https://www.fws.gov/service/financial-assistance.
    Although the Tennessee clubshell, Tennessee pigtoe, and Cumberland 
moccasinshell are only proposed for listing under the Act at this time, 
please let us know if you are interested in participating in recovery 
efforts for these species. Additionally, we invite you to submit any 
new information on these species whenever it becomes available and any 
information you may have for recovery planning purposes (see FOR 
FURTHER INFORMATION CONTACT).
    Section 7(a) of the Act requires Federal agencies to evaluate their 
actions with respect to any species that is proposed or listed as an 
endangered or threatened species and with respect to its critical 
habitat, if any is designated. Regulations implementing this 
interagency cooperation provision of the Act 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 Tennessee clubshell, 
Tennessee pigtoe, and Cumberland moccasinshell that may be subject to 
the section 7 processes are land management or other landscape-altering 
activities on Federal lands administered by the National Park Service, 
U.S. Fish and Wildlife Service, or U.S. Forest Service, as well as 
actions on State, Tribal, local, or private lands that require a 
Federal permit (such as a permit from the U.S. Army Corps of Engineers 
under section 404 of the Clean Water Act (33 U.S.C. 1251 et seq.) or a 
permit from the Service under section 10 of the Act) or that involve 
some other Federal action (such as funding from the Federal Highway 
Administration, Federal Aviation Administration, or 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 local Service Field Office (see FOR FURTHER 
INFORMATION CONTACT) with any specific questions.
    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply to endangered wildlife. 
The prohibitions of section 9(a)(1) of the Act, 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: (1) import 
endangered wildlife 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) 
endangered wildlife within 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 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 
governing permits are codified at 50 CFR 17.22. With regard to 
endangered wildlife, a permit may be issued for the following purposes: 
for scientific purposes, to enhance the propagation or survival of the 
species, and for incidental take in connection with otherwise lawful 
activities. The statute also contains certain exemptions from the 
prohibitions, which are found in sections 9 and 10 of the Act.
    It is the policy of the Service, as published in the Federal 
Register on July 1, 1994 (59 FR 34272), to identify, to the extent 
known at the time a species is listed, specific activities that would 
not be considered likely to result in violation of section 9 of the 
Act. To the extent possible, activities that would be considered likely 
to result in violation will also be identified in as specific a manner 
as possible. The intent of this policy is to increase public

[[Page 57076]]

awareness of the effect of a proposed listing on proposed and ongoing 
activities within the ranges of the species proposed for listing.
    As discussed above, certain activities that are prohibited under 
section 9 may be permitted under section 10 of the Act. In addition, to 
the extent currently known, the following activities would not be 
considered likely to result in violation of section 9 of the Act if we 
list the Tennessee clubshell, Tennessee pigtoe, and Cumberland 
moccasinshell:
    (1) Normal agricultural and silvicultural practices, which are 
carried out in accordance with any existing regulations and best 
management practices; and
    (2) Normal residential landscape activities.
    This list is intended to be illustrative and not exhaustive; 
additional activities that would not be considered likely to result in 
violation of section 9 of the Act may be identified during coordination 
with the local field office, and in some instances (e.g., with new 
information), the Service may conclude that one or more activities 
identified here would be considered likely to result in violation of 
section 9.
    To the extent currently known, the following is a list of examples 
of activities that would be considered likely to result in violation of 
section 9 of the Act, in addition to what is already clear from the 
descriptions of the prohibitions found at 50 CFR part 17, if we list 
the Tennessee clubshell, Tennessee pigtoe, and Cumberland 
moccasinshell:
    (1) Unauthorized handling or collecting of the species;
    (2) Modification of the channel or water flow of any stream in 
which the Tennessee clubshell, Tennessee pigtoe, or Cumberland 
moccasinshell is known to occur;
    (3) Livestock grazing that results in direct or indirect 
destruction of stream habitat; and
    (4) Discharge of chemicals or fill material into any waters in 
which the Tennessee clubshell, Tennessee pigtoe, or Cumberland 
moccasinshell is known to occur.
    This list is intended to be illustrative and not exhaustive; 
additional activities that would be considered likely to result in 
violation of section 9 of the Act may be identified during coordination 
with the local field office, and in some instances (e.g., with new or 
site-specific information), the Service may conclude that one or more 
activities identified here would not be considered likely to result in 
violation of section 9 of the Act. Questions regarding whether specific 
activities would constitute violation of section 9 of the Act should be 
directed to the Asheville Ecological Services Field Office (see FOR 
FURTHER INFORMATION CONTACT).

II. Critical Habitat

Background

    Critical habitat is defined in section 3 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.
    We have found critical habitat to be prudent and determinable for 
all three mussel species and have drafted a proposed critical habitat 
rule for these species. However, the proposed critical habitat rule is 
proceeding on a different timeline from the proposed listing rule 
because we were informed on August 9, 2023, that the Office of 
Information and Regulatory Affairs (OIRA) in the Office of Management 
and Budget (OMB) had determined that our proposed critical habitat rule 
is significant under Executive Order 12866 and will be initiating the 
interagency review process for that proposed rule. Because the Service 
is operating under a court-enforceable deadline requiring us to submit 
the 12-month finding to the Federal Register by August 15, 2023, and 
because E.O. 12866 does not apply to listing determinations, we are 
proceeding with publishing this finding and proposed rule without the 
proposed critical habitat designation. We will publish a proposed 
critical habitat rule for the three mussels following interagency 
review of the proposed critical habitat rule.

Required Determinations

Clarity of the Rule

    We are required by 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.

National Environmental Policy Act (42 U.S.C. 4321 et seq.)

    Regulations adopted pursuant to section 4(a) of the Act are exempt 
from the National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et 
seq.) and do not require an environmental analysis under NEPA. We 
published a notice outlining our reasons for this determination in the 
Federal Register on October 25, 1983 (48 FR 49244). This includes 
listing, delisting, and reclassification rules, as well as critical 
habitat designations. In a line of cases starting with Douglas County 
v. Babbitt, 48 F.3d 1495 (9th Cir. 1995), the courts have upheld this 
position.

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), E.O. 13175 (Consultation and Coordination 
with Indian Tribal Governments), and the Department of the Interior's 
manual at 512 DM 2, we readily acknowledge our responsibility to 
communicate meaningfully with recognized Federal Tribes 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.

References Cited

    A complete list of references cited in this rulemaking is available 
on the internet at https://www.regulations.gov and upon request from 
the Asheville Ecological Services Field Office (see FOR FURTHER 
INFORMATION CONTACT).

[[Page 57077]]

Authors

    The primary authors of this proposed rule are the staff members of 
the Fish and Wildlife Service's Species Assessment Team and the 
Asheville Ecological Services Field Office.

List of Subjects in 50 CFR Part 17

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

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 entries for ``Clubshell, Tennessee'', 
``Moccasinshell, Cumberland'', and ``Pigtoe, Tennessee'' in 
alphabetical order under CLAMS to read as follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

----------------------------------------------------------------------------------------------------------------
                                                                                          Listing citations and
           Common name              Scientific name        Where listed        Status        applicable rules
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                                      Clams
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Clubshell, Tennessee............  Pleurobema oviforme  Wherever found.....            E  [Federal Register
                                                                                          citation when
                                                                                          published as a final
                                                                                          rule]
 
                                                  * * * * * * *
Moccasinshell, Cumberland.......  Medionidus           Wherever found.....            E  [Federal Register
                                   conradicus.                                            citation when
                                                                                          published as a final
                                                                                          rule]
 
                                                  * * * * * * *
Pigtoe, Tennessee...............  Pleuronaia           Wherever found.....            E  [Federal Register
                                   barnesiana.                                            citation when
                                                                                          published as a final
                                                                                          rule]
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *

Martha Williams,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2023-17844 Filed 8-21-23; 8:45 am]
BILLING CODE 4333-15-P