Endangered and Threatened Wildlife and Plants; Endangered Species Status for the Fluted Kidneyshell and Slabside Pearlymussel and Designation of Critical Habitat, 60803-60882 [2012-24019]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 77, Number 193 (Thursday, October 4, 2012)]
[Proposed Rules]
[Pages 60803-60882]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-24019]



[[Page 60803]]

Vol. 77

Thursday,

No. 193

October 4, 2012

Part IV





Department of the Interior





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Fish and Wildlife Service





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50 CFR Part 17





Endangered and Threatened Wildlife and Plants; Endangered Species 
Status for the Fluted Kidneyshell and Slabside Pearlymussel and 
Designation of Critical Habitat; Proposed Rule

Federal Register / Vol. 77 , No. 193 / Thursday, October 4, 2012 / 
Proposed Rules

[[Page 60804]]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2012-0004; 4500030113]
RIN 1018-AY06


Endangered and Threatened Wildlife and Plants; Endangered Species 
Status for the Fluted Kidneyshell and Slabside Pearlymussel and 
Designation of Critical Habitat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
list the fluted kidneyshell (Ptychobranchus subtentum) and slabside 
pearlymussel (Pleuronaia dolabelloides) as endangered species under the 
Endangered Species Act of 1973, as amended (Act), and we propose to 
designate critical habitat for both species. These two species are 
endemic to portions of the Cumberland and Tennessee River systems of 
Alabama, Kentucky, Mississippi, Tennessee, and Virginia. In total, 
approximately 2,218 river kilometers (1,380 river miles) are being 
proposed for designation as critical habitat. The proposed critical 
habitat for fluted kidneyshell is located in Limestone County, Alabama; 
Jackson, Laurel, McCreary, Pulaski, Rockcastle, and Wayne Counties, 
Kentucky; Bedford, Claiborne, Cocke, Fentress, Franklin, Giles, 
Grainger, Greene, Hamblen, Hancock, Hickman, Humphreys, Jefferson, 
Knox, Lincoln, Marshall, Maury, Moore, Morgan, Overton, Perry, Pickett, 
Polk, Scott, and Sevier Counties, Tennessee; and Bland, Lee, Russell, 
Scott, Smyth, Tazewell, Washington, and Wythe Counties, Virginia. The 
proposed critical habitat for slabside pearlymussel is located in 
Colbert, Jackson, Limestone, Madison, and Marshall Counties, Alabama; 
Tishomingo County, Mississippi; Bedford, Bledsoe, Claiborne, Cocke, 
Franklin, Giles, Greene, Hamblen, Hancock, Hickman, Humphreys, Lincoln, 
Marion, Marshall, Maury, Moore, Perry, Polk, and Sequatchie Counties, 
Tennessee; and Bland, Lee, Russell, Scott, Smyth, Tazewell, Washington, 
and Wythe Counties, Virginia.

DATES: We will accept comments received or postmarked on or before 
December 3, 2012. We must receive requests for public hearings, in 
writing, at the address shown in the FOR FURTHER INFORMATION CONTACT 
section by November 19, 2012.

ADDRESSES: Document availability: This proposed rule is available on 
the Internet at https://www.regulations.gov and https://www.fws.gov/cookeville/. 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 field, enter Docket No. FWS-R4-ES-
2012-0004, which is the docket number for this rulemaking. Then, click 
the Search button. You may submit a comment by clicking on ``Comment 
Now!''
    (2) By hard copy: Submit by U.S. mail or hand-delivery to: Public 
Comments Processing, Attn: FWS-R4-ES-2012-0004; Division of Policy and 
Directives Management; U.S. Fish and Wildlife Service; 4401 N. Fairfax 
Drive, MS 2042-PDM; Arlington, VA 22203.
    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 the Information Requested section below for more information).
    The coordinates or plot points or both from which the maps are 
generated are included in the administrative record for this critical 
habitat designation and are available at https://www.fws.gov/cookeville, 
https://www.regulations.gov at Docket No. [FWS-R4-ES-2012-0004], and at 
the Tennessee Ecological Services Field Office) (see FOR FURTHER 
INFORMATION CONTACT). Any additional tools or supporting information 
that we may develop for this critical habitat designation will also be 
available at the above locations.

FOR FURTHER INFORMATION CONTACT: Mary Jennings, Field Supervisor, U.S. 
Fish and Wildlife Service, Tennessee Ecological Services Field Office, 
446 Neal Street, Cookeville, TN 38501; telephone 931-528-6481; 
facsimile 931-528-7075. If you use a telecommunications device for the 
deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-
877-8339.

SUPPLEMENTARY INFORMATION: This document consists of: (1) A proposed 
rule to list the fluted kidneyshell (Ptychobranchus subtentum) and 
slabside pearlymussel (Pleuronaia dolabelloides) as endangered species; 
and (2) proposed critical habitat designations for these two species.

Executive Summary

    Why we need to publish a rule. Under the Act, a species or 
subspecies may warrant protection through listing if it is an 
endangered or threatened species throughout all or a significant 
portion of its range. Both species have been eliminated from more than 
50 percent of the streams from which they were historically known, and 
are now limited to a handful of viable populations, all of which are 
facing a variety of threats, including impoundments, mining, poor water 
quality, excessive sedimentation, and environmental contaminants.
    The basis for our action. Under the Act, a species may be 
determined to be endangered or threatened based on any of five factors: 
(A) Destruction, modification, or curtailment of its habitat or range; 
(B) overutilization; (C) disease or predation; (D) inadequate existing 
regulatory mechanisms; or (E) other natural or manmade factors. These 
two mussel species are facing threats due to three of these five 
factors (A, D, and E). The Act also requires that the Service designate 
critical habitat at the time of listing provided that it is prudent and 
determinable. We have determined that designating critical habitat is 
both prudent and determinable (see Critical Habitat for the Fluted 
Kidneyshell and Slabside Pearlymussel section below), and propose a 
total of approximately 2,218 river kilometers (rkm) (1,380 river miles 
(rmi)) of critical habitat in five States. Twenty-four units covering 
approximately 1,899 river kilometers (rkm) (1,181 river miles (rmi)) of 
critical habitat are being proposed for the fluted kidneyshell in 
Alabama, Kentucky, Tennessee, and Virginia. Thirteen units covering 
approximately 1,562 rkm (970 rmi) of critical habitat are being 
proposed for the slabside pearlymussel in Alabama, Mississippi, 
Tennessee, and Virginia.
    We will seek peer review. In addition to seeking public comments, 
we will solicit peer review of this proposal from at least three 
experts knowledgeable in mussel biology and basic conservation biology 
principles and concepts. Because we will consider all comments and 
information received during the comment period, our final 
determinations may differ from this proposal

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

[[Page 60805]]

information from other concerned governmental agencies, the scientific 
community, industry, or any other interested parties concerning this 
proposed rule. We particularly seek comments concerning:
    (1) Biological, commercial trade, or other relevant data concerning 
any threats (or lack thereof) to these species and regulations that may 
be addressing those threats.
    (2) Additional information concerning the historical and current 
status, range, distribution, and population size of either of these 
species, including the locations of any additional populations.
    (3) Any information on the biological or ecological requirements of 
these species, and ongoing conservation measures for the species and 
their habitat.
    (4) Any information regarding water quality data that may be 
helpful in determining the water quality parameters necessary for the 
fluted kidneyshell and the slabside pearlymussel.
    (5) Current or planned activities in the areas occupied by these 
species and possible impacts of these activities on these species.
    (6) The factors that are the basis for making a listing 
determination for a species under section 4(a) of the Act (16 U.S.C. 
1531 et seq.), which are:
    (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.
    (7) The reasons why we should or should not designate habitat as 
``critical habitat'' under section 4 of the Act including whether there 
are threats to these species from human activity, the degree of which 
can be expected to increase due to the designation, and whether that 
increase in threat outweighs the benefit of designation such that the 
designation of critical habitat may not be prudent.
    (8) Specific information on:
    (a) The amount and distribution of habitat for the fluted 
kidneyshell and slabside pearlymussel;
    (b) What areas, that were occupied at the time of the proposed 
listing and that contain features essential to the conservation of 
these species, should be included in the designation and why;
    (c) Special management considerations or protection that may be 
needed in critical habitat areas we are proposing, including managing 
for the potential effects of climate change; and
    (d) What areas not occupied at the time of the proposed listing are 
essential for the conservation of these species and why.
    (9) Land use designations and current or planned activities in the 
subject areas and their possible impacts on proposed critical habitat.
    (10) Information on the projected and reasonably likely impacts of 
climate change on these species and proposed critical habitat.
    (11) Any probable economic, national security, or other relevant 
impacts of designating any area that may be included in the final 
designation; in particular, we seek information on any impacts on small 
entities or families, and the benefits of including or excluding areas 
that exhibit these impacts.
    (12) Whether any specific areas we are proposing for critical 
habitat designation should be considered for exclusion under section 
4(b)(2) of the Act, and whether the benefits of potentially excluding 
any specific area outweigh the benefits of including that area under 
section 4(b)(2) of the Act.
    (13) Any impact that critical habitat designation would have, 
positive or negative, on conservation efforts associated with 
designated nonessential experimental populations for other listed 
species in the lower Holston and French Broad river systems in 
Tennessee, or the North Fork Holston River in Virginia.
    (14) Information on habitat suitability for these two mussels in 
the proposed units that are not occupied at the time of the proposed 
listing, including the Rockcastle River, Kentucky, and the Sequatchie 
River, Tennessee.
    (15) Whether we could improve or modify our approach to designating 
critical habitat in any way to provide for greater public participation 
and understanding, or to better accommodate public concerns and 
comments.
    Please note that submissions merely stating support for or 
opposition to the action under consideration without providing 
supporting information, although noted, will not be considered in 
making a determination, as section 4(b)(1)(A) of the Act directs that 
determinations as to whether any species is a threatened or endangered 
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 Web site. 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. 
Please include sufficient information with your comments to allow us to 
verify any scientific or commercial information you include.
    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, or by 
appointment, during normal business hours, at the U.S. Fish and 
Wildlife Service, Tennessee Ecological Services Field Office (see FOR 
FURTHER INFORMATION CONTACT).

Previous Federal Actions

    The fluted kidneyshell was first identified as a candidate for 
protection under the Act in the October 25, 1999, Federal Register (64 
FR 57534). Candidate species are those taxa for which the Service has 
sufficient information on their biological status and threats to list 
as an endangered or threatened species under the Act but for which the 
development of a listing regulation has been precluded to date by other 
higher priority listing activities. Candidates are assigned listing 
priority numbers (LPNs) based on immediacy and the magnitude of threat, 
as well as their taxonomic status. A lower LPN corresponds to a higher 
conservation priority, and we consider the LPN when prioritizing and 
funding conservation actions. In our 1999 (64 FR 57534), 2001 (66 FR 
54808), 2002 (67 FR 40657), 2004 (69 FR 24876), 2005 (70 FR 24870), and 
2006 (71 FR 53756) Federal Register Candidate Notices of Review, we 
identified the species as having an LPN of five, in accordance with our 
priority guidance published on September 21, 1983 (48 FR 43098). An LPN 
of five reflects threats that are nonimminent and high in magnitude, as 
well as the taxonomic classification of the fluted kidneyshell as a 
full species. We also determined that publication of a proposed rule to 
list the fluted kidneyshell was precluded by our work on higher 
priority listing actions. On May 11, 2004, we received a petition to 
list the fluted kidneyshell as an

[[Page 60806]]

endangered species. We published our petition finding in the 2005 
Candidate Notice of Review (70 FR 24869), and have done so annually in 
subsequent years.
    On December 6, 2007 (72 FR 69034), we changed the LPN for the 
fluted kidneyshell from five to two. A listing priority of two reflects 
threats that are both imminent and high in magnitude, as well as the 
taxonomic classification of the fluted kidneyshell as a full species. 
In our 2008 (73 FR 75176), 2009 (74 FR 57804), 2010 (75 FR 69222), and 
2011 (76 FR 66370) Candidate Notices of Review, we retained a listing 
priority number of two for this species.
    The slabside pearlymussel was first identified as a candidate for 
protection under the Act in the May 22, 1984, Federal Register (49 FR 
21664). As a candidate, it was assigned a ``Category 2'' designation, 
which was given to those species with some evidence of vulnerability, 
but for which additional biological information was needed to support a 
proposed rule to list as endangered or threatened. In our 1989 (54 FR 
554), 1991 (56 FR 58804), and 1994 (59 FR 58982) Federal Register 
Candidate Notices of Review, we retained a Category 2 designation for 
this species. Assigning categories to candidate species was 
discontinued in our Candidate Notice of Review dated February 28, 1996, 
and only species for which the Service had sufficient information on 
biological vulnerability and threats to support issuance of a proposed 
rule were retained as candidate species (61 FR 7596).
    On October 25, 1999, we identified the slabside pearlymussel in the 
Federal Register as a candidate species with a listing priority number 
of five (64 FR 57534). In our 2001 (66 FR 54808), 2002 (67 FR 40657), 
2004 (69 FR 24876), 2005 (70 FR 24870), 2006 (71 FR 53756), and 2007 
(72 FR 69034) Candidate Notices of Review, we determined that 
publication of a proposed rule to list the species was precluded by our 
work on higher priority listing actions and retained a listing priority 
number of five for this species, in accordance with our priority 
guidance published on September 21, 1983 (48 FR 43098). We published a 
petition finding for slabside pearlymussel in the 2005 Candidate Notice 
of Review (70 FR 24870) in response to a petition received on May 11, 
2004, and have published annual petition findings in subsequent 
Candidate Notices of Review.
    On December 10, 2008 (73 FR 75176), we changed the listing priority 
number for the slabside pearlymussel from five to two. In our 2009 (74 
FR 57804), 2010 (75 FR 69222), and 2011 (76 FR 66370) Candidate Notices 
of Review, we retained a listing priority number of two for this 
species.

Background

    It is our intent to discuss only those topics directly relevant to 
the listing and critical habitat designations for the fluted 
kidneyshell and slabside pearlymussel in this proposed rule. A summary 
of topics relevant to this proposed rule is provided below. Additional 
information on both species may be found in the most recent Candidate 
Notice of Review, which was published October 26, 2011 (76 FR 66370).

Introduction

    North American mussel fauna are more biologically diverse than 
anywhere else in the world, and historically numbered around 300 
species (Williams et al. 1993, p. 6). Mussels are in decline, however, 
and in the past century have become more imperiled than any other group 
of organisms (Williams et al. 2008, p. 55). Approximately 72 percent of 
North America's mussel species are considered vulnerable to extinction 
or possibly extinct (Williams et al. 1993, p. 6). Within North America, 
the southeastern United States is the hot spot for mussel diversity. 
Seventy-five percent of southeastern mussel species are in varying 
degrees of rarity or possibly extinct (Neves et al. 1997, pp. 47-51). 
The central reason for the decline of mussels is the modification and 
destruction of their habitat, especially from dams, degraded water 
quality, and sedimentation (Neves et al. 1997, p. 60; Bogan 1998, p. 
376). These two mussels, like many other southeastern mussel species, 
have undergone considerable reductions in total range and population 
density.
    Most studies of the distribution and population status of the 
fluted kidneyshell and slabside pearlymussel presented below were 
conducted after the early 1960s. Gordon and Layzer (1989, entire), 
Winston and Neves (1997, entire), and Parmalee and Bogan (1998, pp. 
204-205) give most of the references for regional stream surveys. In 
addition to these publications, we have obtained more current, 
unpublished distribution and status information from State heritage 
programs, agency biologists, and other knowledgeable individuals.
    These two species are bivalve mussels and are endemic to the 
Cumberland and Tennessee River drainages. The Cumberland River drainage 
originates in southeastern Kentucky and flows southwest across 
Tennessee before turning north and reentering Kentucky to empty into 
the lower Ohio River. The Cumberland River drainage spans the 
Appalachian Plateaus and Interior Low Plateaus Physiographic Provinces. 
The Tennessee River originates in southwest Virginia and western North 
Carolina, eastern Tennessee, and northern Georgia and flows 
southwesterly into western Tennessee and Alabama, then turns north and 
flows into Kentucky, before emptying into the Ohio River. The larger 
Tennessee River drainage spans five physiographic provinces, including 
the Blue Ridge, Valley and Ridge, Appalachian Plateaus, Interior Low 
Plateaus, and Coastal Plain.

Fluted Kidneyshell

Taxonomy and Species Description

    The fluted kidneyshell, Ptychobranchus subtentum (Say, 1825), is in 
the family Unionidae (Turgeon et al. 1998, p. 36). The following 
description, biology, and life history of the fluted kidneyshell is 
taken from Parmalee and Bogan (1998, pp. 204-205) and Williams et al. 
(2008, pp. 627-629). The fluted kidneyshell is a relatively large 
mussel that reaches about 13 centimeters (cm) (5 inches (in)) in 
length. The shape of the shell is roughly oval elongate, and the solid, 
relatively heavy valves (shells) are moderately inflated. A series of 
flutings (parallel ridges or grooves) characterizes the posterior slope 
of each valve. Shell texture is smooth and somewhat shiny in young 
specimens, becoming duller with age. Shell color is greenish yellow, 
becoming brownish with age, with several broken, wide green rays. 
Internally, there are two types of teeth, which are raised, 
interlocking structures used to stabilize opposing shell halves. The 
pseudocardinal teeth are stumpy and triangular in shape. The lateral 
teeth are relatively heavy and nearly straight, with two in the left 
valve and one in the right valve. The color of the nacre (mother-of-
pearl) is bluish-white to dull white with a wash of salmon in the older 
part of the shell (beak cavity).

Habitat and Life History

    Mussels generally live embedded in the bottom of rivers and other 
bodies of water. They siphon water into their shells and across four 
gills that are specialized for respiration, food collection, and 
brooding larvae in females. Food items include detritus (disintegrated 
organic debris), algae, diatoms, and bacteria (Strayer et al. 2004, pp. 
430-431). Adult mussels can obtain their food by deposit feeding, 
pulling in food from the sediment and its interstitial (pore) water, 
and pedal-

[[Page 60807]]

feeding directly from the sediment (Yeager et al. 1994, pp. 217-221; 
Vaughn and Hakenkamp 2001, 1432-1438). Adults are filter feeders and 
generally orient themselves on or near the substrate surface to take in 
food and oxygen from the water column. Juveniles typically burrow 
completely beneath the substrate surface and are deposit or pedal 
(foot) feeders, meaning that they bring food particles that adhere to 
the foot while it is extended outside the shell inside the shell for 
ingestion, until the structures for filter feeding are more fully 
developed (Yeager et al. 1994, pp. 200-221; Gatenby et al. 1996, p. 
604). However, adults are also capable of deposit feeding and may do so 
depending on the availability of food resources (Nichols et al. 2005, 
pp. 90-93).
    Mussels tend to grow relatively rapidly for the first few years; 
then growth slows appreciably after sexual maturity, when energy is 
being diverted from growth to reproductive activities. Mussel longevity 
varies tremendously among species (from 4 to 5 years to well over 100 
years), but most species live 10 to 50 years (Haag and Rypel 2011, pp. 
230-236). Relatively large, heavy-shelled riverine species tend to be 
slower growing and have longer life spans. By thin-sectioning the 
valves, various authors have aged fluted kidneyshell from the Clinch 
River at 26 and 55 years (Henley et al. 2002, p. 19; Davis and Layzer 
2012, p. 92). Females can become sexually mature at age 5 (Davis and 
Layzer 2012, p. 79).
    The gametogenic cycle (annual cycle in the development of 
reproductive cells or gametes) of fluted kidneyshell, like most 
mussels, is probably regulated by annual temperature regimes (Davis and 
Layzer, p. 90). Most mussels, including the fluted kidneyshell, have 
separate sexes. Males expel sperm into the water column, which are 
drawn in by females through their incurrent apertures or siphons. It 
has been hypothesized that pheromones might trigger synchronous sperm 
release among males, because all fertilization observed by females from 
the Clinch River occurred in fewer than 5 days (Davis and Layzer 2012, 
p. 90). Fertilization takes place internally, and the resulting zygotes 
develop into specialized larvae, termed glochidia, inside the water 
tubes of the females' gills. The fluted kidneyshell, along with other 
members of its genus, is unique in that the marsupial portion of the 
outer gills (portion of a brooding female's gill which holds embryos 
and glochidia) are folded in a curtain-like fashion. The fluted 
kidneyshell is thought to have a late summer or early fall 
fertilization period with the glochidia overwintering. Davis and Layzer 
(2012, p. 90) observed embryo development within the marsupium (brood 
pouch) at 4 weeks after fertilization. The following spring or early 
summer, glochidia are released as conglutinates, which are similar to 
cold capsules or gelatinous containers with scores of glochidia within. 
Davis and Layzer (2012, p. 86) report an average of 208 conglutinates 
and an average fecundity (total reproductive output) of 247,000 
glochidia per female. Davis and Layzer (2012, p. 92) report a skewed 
adult sex ratio of 1.9 females per 1 male in the Clinch River, in 
Tennessee, although the cause of the skewed ratio is unknown. Using the 
observed sex ratio and percent of females that were gravid, Davis and 
Layzer (2012, p. 92) hypothesized that some females go through 
reproductive ``pausing'' periods to acquire the energy reserves needed 
to produce gametes in subsequent years.
    Glochidia must come into contact with a specific host fish(es) 
quickly in order for their survival to be ensured. Without the proper 
species of host fish, the glochidia will perish. Conglutinate masses 
often mimic food items of glochidial fish hosts in order to attract and 
infest potential host fishes. Fluted kidneyshell conglutinates are 
shaped like black fly (Simuliidae) pupae and have an adhesive end that 
sticks to silt-free stones on the stream bottom, with an orientation 
that is also similar to that of blackfly pupae (Barnhart and Roberts 
1997, p. 17; Barnhart et al. 2008, p. 377; Williams et al. 2008, p. 
628). Insects are common food items of many stream fishes, including 
the fluted kidneyshell's host fishes, which include the barcheek darter 
(Etheostoma obeyense), fantail darter (E. flabellare), rainbow darter 
(E. caeruleum), redline darter (E. rufilineatum), bluebreast darter (E. 
camurum), dusky darter (Percina sciera), and banded sculpin (Cottus 
carolinae). These fishes are tricked into thinking that they have an 
easy insect meal when in fact they have infected themselves with 
parasitic mussel glochidia (Parmalee and Bogan 1998, p. 205; Davis and 
Layzer 2012, p. 88).
    After a few weeks parasitizing the host fish's gill, newly 
metamorphosed juveniles drop off to begin a free-living existence on 
the stream bottom. Unless they drop off in suitable habitat, they will 
perish. Thus, the complex life history of the fluted kidneyshell and 
other mussels has many critical steps that may prevent successful 
reproduction or recruitment of juveniles into existing populations or 
both.
    The fluted kidneyshell occurs in medium-sized creeks to large 
rivers, inhabiting sand and gravel substrates in relatively shallow 
riffles and shoals with moderate to swift current (Williams et al. 
2008, p. 628). In comparison to some co-occurring species, the fluted 
kidneyshell demonstrates strong habitat specificity by being associated 
with faster flows, greater shear stress (force of water pressure and 
velocity on the substrate), and low substrate embeddedness (Ostby 2005, 
pp. 51, 142-3).

Historical Range and Distribution

    The fluted kidneyshell is a Cumberlandian Region mussel, meaning it 
is restricted to the Cumberland (in Kentucky and Tennessee) and 
Tennessee (in Alabama, Kentucky, Tennessee, and Virginia) River 
systems. Historically, this species occurred in the Cumberland River 
mainstem from below Cumberland Falls in southeastern Kentucky 
downstream through the Tennessee portion of the river to the vicinity 
of the Kentucky-Tennessee State line. In the Tennessee River mainstem 
it occurred from eastern to western Tennessee. Records are known from 
the following Cumberland River tributaries: Horse Lick Creek [KY], 
Middle Fork Rockcastle River [KY], Rockcastle River [KY], Buck Creek 
[KY], Rock Creek [KY], Kennedy Creek [KY], Little South Fork [KY], Big 
South Fork [KY, TN], Pitman Creek [KY], Otter Creek [KY], Wolf River 
[TN], Town Branch [TN], West Fork Obey River [TN], Obey River [TN], 
Caney Fork [TN], South Harpeth River [TN], and West Fork Red River 
[KY]. In addition, it is known from the following Tennessee River 
tributaries: South Fork Powell River [VA], Powell River [TN, VA], 
Indian Creek [VA], Little River [VA], Clinch River [TN, VA], Copper 
Creek [VA], North Fork Holston River [TN, VA], Big Moccasin Creek [VA], 
Middle Fork Holston River [VA], South Fork Holston River [TN, VA], 
Holston River [TN], Nolichucky River [TN], West Prong Little Pigeon 
River [TN], Tellico River [TN], French Broad River [TN], Little 
Tennessee River [TN], Hiwassee River [TN], Flint River [AL], Limestone 
Creek [AL], Elk River [AL, TN], Shoal Creek [AL], Buffalo River [TN], 
and Duck River [TN] (Gordon and Layzer 1989, entire; Winston and Neves 
1997, entire; Parmalee and Bogan 1998, pp. 204-205; Layzer and Scott 
2006, p. 481). The fluted kidneyshell's known historical and current 
occurrences, by water body and county, are shown in Table 1 below.

[[Page 60808]]



                  Table 1--Known Historical and Current Occurrences for the Fluted Kidneyshell
----------------------------------------------------------------------------------------------------------------
          Water body                 Drainage             County        State         Historical or current
----------------------------------------------------------------------------------------------------------------
Cumberland River.............  Cumberland..........  McCreary,        KY        Historical.
                                                      Pulaski,
                                                      Russell.
Cumberland River.............  Cumberland..........  Stewart........  TN        Historical.
Middle Fork Rockcastle River.  Cumberland..........  Jackson........  KY        Historical and Current.
Horse Lick Creek.............  Cumberland..........  Jackson,         KY        Historical and Current.
                                                      Rockcastle.
Rockcastle River.............  Cumberland..........  Laurel,          KY        Historical.
                                                      Pulaski,
                                                      Rockcastle.
Buck Creek...................  Cumberland..........  Pulaski........  KY        Historical and Current.
Big South Fork Cumberland      Cumberland..........  McCreary,        KY        Historical and Current.
 River.                                               Pulaski.
Big South Fork Cumberland      Cumberland..........  Fentress,        TN        Historical and Current.
 River.                                               Morgan, Scott.
Rock Creek...................  Cumberland..........  McCreary.......  KY        Historical and Current.
Little South Fork Cumberland   Cumberland..........  McCreary, Wayne  KY        Historical and Current.
 River.
Kennedy Creek................  Cumberland..........  Wayne..........  KY        Historical.
Pitman Creek.................  Cumberland..........  Pulaski........  KY        Historical.
Otter Creek..................  Cumberland..........  Wayne..........  KY        Historical.
Wolf River...................  Cumberland..........  Fentress,        TN        Historical and Current.
                                                      Pickett.
Town Branch..................  Cumberland..........  Pickett........  TN        Historical and Current.
Obey River...................  Cumberland..........  ?..............  TN        Historical.
West Fork Obey River.........  Cumberland..........  Overton........  TN        Historical and Current.
Caney Fork River.............  Cumberland..........  ?..............  TN        Historical.
South Harpeth River..........  Cumberland..........  Davidson.......  TN        Historical.
West Fork Red River..........  Cumberland..........  Todd...........  KY        Historical.
South Fork Powell River......  Tennessee...........  Wise...........  VA        Historical.
Powell River.................  Tennessee...........  Claiborne,       TN        Historical and Current.
                                                      Hancock.
Powell River.................  Tennessee...........  Campbell, Union  TN        Historical.
Powell River.................  Tennessee...........  Lee............  VA        Historical and Current.
Indian Creek.................  Tennessee...........  Tazewell.......  VA        Historical and Current.
Clinch River.................  Tennessee...........  Hancock........  TN        Historical and Current.
Clinch River.................  Tennessee...........  Anderson,        TN        Historical.
                                                      Claiborne,
                                                      Grainger,
                                                      Roane, Union.
Clinch River.................  Tennessee...........  Russell, Scott,  VA        Historical and Current.
                                                      Tazewell, Wise.
Little River.................  Tennessee...........  Russell,         VA        Historical and Current.
                                                      Tazewell.
Copper Creek.................  Tennessee...........  Scott..........  VA        Historical and Current.
North Fork Holston River.....  Tennessee...........  Hawkins,         TN        Historical.
                                                      Sullivan.
North Fork Holston River.....  Tennessee...........  Bland, Scott,    VA        Historical and Current.
                                                      Smyth,
                                                      Washington.
Big Moccasin Creek...........  Tennessee...........  Scott..........  VA        Historical and Current.
Middle Fork Holston River....  Tennessee...........  Smyth..........  VA        Historical and Current.
South Fork Holston River.....  Tennessee...........  Sullivan.......  TN        Historical.
South Fork Holston River.....  Tennessee...........  Washington.....  VA        Historical.
Holston River................  Tennessee...........  Grainger,        TN        Historical.
                                                      Hamblen,
                                                      Jefferson,
                                                      Knox.
French Broad River...........  Tennessee...........  ?..............  TN        Historical.
Tennessee River..............  Tennessee...........  Colbert,         AL        Historical.
                                                      Jackson,
                                                      Lauderdale.
Tennessee River..............  Tennessee...........  Decatur, Knox,   TN        Historical.
                                                      Meigs, Rhea.
Nolichucky River.............  Tennessee...........  Greene.........  TN        Historical and Current.
West Prong Little Pigeon       Tennessee...........  Sevier.........  TN        Historical.
 River.
Tellico River................  Tennessee...........  Monroe.........  TN        Historical.
Little Tennessee River.......  Tennessee...........  Monroe.........  TN        Historical.
Hiwassee River...............  Tennessee...........  Polk...........  TN        Historical.
Flint River..................  Tennessee...........  Madison........  AL        Historical.
Limestone Creek..............  Tennessee...........  Limestone......  AL        Historical.
Elk River....................  Tennessee...........  Limestone......  AL        Historical.
Elk River....................  Tennessee...........  Coffee,          TN        Historical.
                                                      Franklin.
Shoal Creek..................  Tennessee...........  Limestone......  AL        Historical.
Duck River...................  Tennessee...........  Bedford,         TN        Historical and Current.
                                                      Marshall,
                                                      Maury.
Buffalo River................  Tennessee...........  Lewis..........  TN        Historical.
----------------------------------------------------------------------------------------------------------------
Note: A ? represents a lack of specific locational information in the museum and literature record.

    Prior to 1980, the fluted kidneyshell was fairly widespread and 
common in many Cumberlandian Region streams based on collections in 
museums and from the literature record. The extirpation of this species 
from numerous streams within its historical range indicates that 
substantial population losses and range reductions have occurred.

Current Range and Distribution

    In this document, populations of the fluted kidneyshell are 
generally considered extant (current) if live individuals or fresh dead 
specimens have been collected since circa 1980. This criterion (circa 
1980) was chosen because a large number of collections were conducted 
in the 1980s in the Cumberland and Tennessee River systems and due to 
the longevity of these species (40-55 years), they are still thought to 
occur in these areas.
    Some of the historical occurences have not been surveyed since the 
1980s. Based on this criterion, the species appears to be limited to 
Horse Lick Creek [KY], Middle Fork Rockcastle River [KY], Buck Creek 
[KY], Rock Creek [KY], Little South Fork Cumberland River [KY], Big 
South Fork Cumberland River [KY, TN], Wolf River [TN], Town Branch 
[TN], and West Fork Obey River [TN] in the Cumberland River system; and 
the Powell River [TN, VA], Indian Creek [VA], Little River

[[Page 60809]]

[VA], Clinch River [TN, VA], Copper Creek [VA], North Fork Holston 
River [VA], Big Moccasin Creek [VA], Middle Fork Holston River [VA], 
Nolichucky River [TN], and Duck River [TN] in the Tennessee River 
system (see Table 1). Where two or more stream populations occur 
contiguously with no barriers, such as impoundments or long reaches of 
unoccupied habitat, they are considered single population segments or 
clusters. Multi-stream population segments include the Wolf River and 
its tributary Town Branch in the Cumberland River system, and Clinch 
River and Copper Creek (but not the other two upper Clinch tributaries, 
Indian Creek and Little River) in the Tennessee River system. Thus, we 
consider 17 of 40 populations of fluted kidneyshell to be extant. The 
fluted kidneyshell has been eliminated from more than 50 percent of 
streams from which it was historically known.
    Other populations considered extant at the time this species was 
elevated to candidate status in 1999 (e.g., Rockcastle River, Kennedy 
Creek) are now considered to be extirpated. In addition, the population 
in the upper North Fork Holston River, although still large, has 
declined substantially since circa 2000. The North Fork Holston River 
population is predominately composed of large individuals, unlike the 
Clinch River population, which is skewed towards smaller size classes 
(Ostby et al. 2010, pp. 7, 22-24). These differences in population 
characteristics are a clear indication that recruitment in the Clinch 
River population is more observable than the population in the North 
Fork Holston River.
    Resource managers have been making attempts to reintroduce the 
fluted kidneyshell into historical habitat over the past decade. In 
Tennessee, thousands of individuals of the species have been 
reintroduced into three sites in the upper Duck River, and into two 
sites in the Nolichucky River, by Tennessee Wildlife Resource Agency 
(TWRA) biologists translocating adult individuals from the Clinch River 
(Hubbs 2011, unpubl. data). In 2010, six individuals were collected 
during a quantitative survey at Lillard's Mill in the Duck River, 
confirming some level of survival and persistence of the reintroduced 
population (Hubbs 2011, unpubl. data). The individuals collected 
appeared in good condition and had grown noticeably since their release 
(as evidenced by external shell marks), but recruitment has yet to be 
documented (Hubbs 2011, unpubl. data). In 2008, the Kentucky Department 
of Fish and Wildlife Resources (KDFWR) translocated 144 individuals 
from the Clinch River into the Big South Fork of the Cumberland River, 
Kentucky (Hubbs 2011, unpubl. data). It is not known if the Nolichucky 
or Big South Fork reintroductions have been successful. Approximately 
691 adult individuals of the species have been translocated from the 
Clinch River, Tennessee, into the Little Tennessee River bypass reach 
below Calderwood Dam, Tennessee (Moles 2012, pers. comm.). The Virginia 
Department of Game and Inland Fisheries (VDGIF) reintroduced 58 adults 
into Indian Creek, a tributary to the Clinch River, using Clinch River 
stock. They have also propagated and released 562 juveniles into the 
North Fork Holston River (Duncan 2012, pers. comm.).
    The extant fluted kidneyshell populations (including the 
potentially reintroduced populations) in the Cumberlandian Region 
generally represent small, isolated occurrences. Only in the Clinch 
River is a population of the fluted kidneyshell known to be large, 
stable, and viable, but in a relatively short reach of river primarily 
in the vicinity of the Tennessee-Virginia State line. Jones (2012, 
unpub. data) estimates 500,000 to 1,000,000 individuals occur in the 
Clinch River from just a 32-river-kilometer (rkm) (20-river-mile (rmi)) 
reach (rkm 309 to 277 (rmi 172 to 192)). Live adults and juveniles have 
been observed over the past 10 years in shoal habitats in the upper 
Clinch River, Virginia, particularly at and above Cleveland Islands, 
and many more fresh dead shells have been collected in muskrat middens 
in this reach. Eckert and Pinder (2010, pp. 23-30) collected 18 
individuals in quantitative samples and 11 individuals in semi-
quantitative samples in the Clinch River at Cleveland Island in 2008, 
and 15 individuals in quantitative samples and 62 individuals in semi-
quantitative samples in the Clinch River at Cleveland Island in 2002. 
Ostby and Angermeier (2011, entire) found two live individuals in the 
Little River (tributary to Clinch River). Henley et al. (1999, pp. 20, 
22) collected live individuals at 6 of 25 sites surveyed in the Middle 
Fork Holston River in 1997 and 1998. The fluted kidneyshell was found 
in Copper Creek between creek rkm 2 and 31 (rmi 1 and 19) (Hanlon et 
al. 2009, pp. 15-17). Petty et al. (2006, pp. 4, 36) found the species 
between Copper Creek rkm 24 and 31 (rmi 15 and 19) and reported 
evidence of reproduction and recruitment of the species at these 
locations. In 2008-09, 35 live individuals were found at 5 of 21 sites 
sampled in the Powell River, in both Tennessee and Virginia, and there 
was some indication of relatively recent recruitment (Johnson et al. in 
press, Table 4). Ostby et al. (2010, pp. 16-20) observed 772 
individuals during qualitative surveys and 10 individuals in 
quantitative surveys in the North Fork Holston River, Virginia.
    Live fluted kidneyshell have not been collected in the Middle Fork 
Rockcastle River since the mid-1980s (Layzer and Anderson 1992, p. 64). 
Haag and Warren (2004, p. 16) collected only fresh dead shell material 
in Horse Lick Creek, and reported that a small, extremely vulnerable 
population of the fluted kidneyshell may exist there, but at very low 
levels that they were not able to detect. Warren and Haag (2005, pp. 
1384, 1388-1396) reported a vast reduction of the once sizable Little 
South Fork population since the late 1980s. Live fluted kidneyshell 
have not been collected in the Big South Fork since the mid-1980s 
(Ahlstedt et al. 2003-2004, p. 65). In 2010, two individuals were found 
in Buck Creek and collected for future propagation efforts (McGregor 
2010, unpub. data). Live fluted kidneyshell have not been collected in 
Rock Creek since 1988 (Layzer and Anderson 1992, p. 68). Layzer and 
Anderson (1992, p. 22) collected fluted kidneyshell at two sites in the 
West Fork Obey River. A small but recruiting population occurs in the 
Wolf River, Tennessee, based on 2005-06 sampling (Moles et al. 2007, p. 
79). This may be the best population remaining in the entire Cumberland 
River system, where most populations are very restricted in range and 
are highly imperiled. Given its longevity, small populations of this 
long-lived species may persist for decades despite total recruitment 
failure. Therefore, at least 5 of the extant populations may be 
functionally extirpated (e.g., Horse Lick Creek, Middle Fork Rockcastle 
River, Little South Fork Cumberland River, Rock Creek, West Fork Obey 
River).

Population Estimates and Status

    Extirpated from both the Cumberland and Tennessee River mainstems, 
the fluted kidneyshell has been eliminated from approximately 50 
percent of the total number of streams from which it was historically 
known. Population size data gathered during the past decade or two 
indicate that the fluted kidneyshell is rare in nearly all extant 
populations, the Clinch River being a notable exception. The fluted 
kidneyshell is particularly imperiled in Kentucky. Haag and Warren 
(2004, p. 16) reported that a small, extremely vulnerable population of 
the fluted kidneyshell may exist in Horse Lick Creek, but at

[[Page 60810]]

extremely low levels that they were not able to detect. They only 
collected fresh dead shell material in Horse Lick Creek. The vast 
reduction of the once sizable Little South Fork population since the 
late 1980s (Warren and Haag 2005, pp. 1384, 1388-1396) and the tenuous 
status of the other Cumberland River system populations put the species 
at risk of total extirpation from that Cumberland River system. In 
addition, the populations in the Powell River (post-1980) and the 
Middle Fork (post-1995) and upper North Fork (post-2000) Holston Rivers 
in Virginia have declined in recent years based on recent survey 
efforts (Henley et al. 1999, p. 23; Ahlstedt et al. 2005, p. 9; Jones 
and Neves 2007, p. 477; Johnson et al. in press). Populations of the 
fluted kidneyshell remain locally abundant in certain reaches of the 
North Fork Holston River but are reduced in overall range within the 
river (Ostby and Neves 2005, 2006a, and 2006b, entire; Dinkins 2010a, 
p. 3-1). Declines in mussel community abundance in the North Fork 
Holston River have been in the form of several die-offs. The cause for 
the observed die-offs is unknown (Jones and Neves 2007, p. 479), but 
may be related to agricultural runoff (Hanlon et al. 2009, p. 11).
    In summary, the fluted kidneyshell has been eliminated from 
approximately 50 percent of the total number of streams from which it 
was historically known. Populations in Buck Creek, Little South Fork, 
Horse Lick Creek, Powell River, and North Fork Holston River have 
clearly declined over the past two decades. Based on recent 
information, the overall population status of the fluted kidneyshell 
rangewide is declining. A few populations are considered to be viable 
(e.g., Wolf, Clinch, Little, North Fork Holston Rivers). However, all 
other populations are of questionable viability, with some on the verge 
of extirpation (e.g., Horse Lick and Rock Creeks). Newly reintroduced 
populations will hopefully begin to reverse the overall downward trend 
of this species.
    The fluted kidneyshell was considered a species of special concern 
by Williams et al. (1993, p. 14), but two decades later is considered 
endangered in a reassessment of the North American mussel fauna by the 
Endangered Species Committee of the American Fisheries Society (Butler 
2012, pers. comm.). The fluted kidneyshell is listed as a species of 
Greatest Conservation Need (GCN) in the Kentucky, Tennessee, and 
Virginia State Wildlife Action Plans (KDFWR 2005; TWRA 2005; VDGIF 
2005).

Slabside Pearlymussel

Taxonomy and Species Description

    The taxonomic status of the slabside pearlymussel (family 
Unionidae) as a distinct species is undisputed within the scientific 
community. The species is recognized as Lexingtonia dolabelloides (I. 
Lea, 1840) in the ``Common and Scientific Names of Aquatic 
Invertebrates from the United States and Canada: Mollusks, Second 
Edition'' (Turgeon et al. 1998, p. 35). However, there are currently 
differing opinions on the appropriate genus to use for the species. 
Genetic analyses by Bogan et al. (unpublished data), as cited by 
Williams et al. (2008, p. 584), suggests that the type genus of 
Lexingtonia, Unio subplana Conrad, 1837, is synonymous with Fusconaia 
masoni (Conrad, 1834). Lexingtonia is therefore a junior synonym of 
Fusconaia, making Lexingtonia no longer available as a valid genus of 
mussel under the rules of the International Code of Zoological 
Nomenclature (Williams 2011, pers. comm.). Analyses by Campbell et al. 
(2005, pp. 141, 143, 147) and Campbell and Lydeard (2012a, pp. 3-6, 9; 
2012b, pp. 25-27, 30, 34) suggest that ``Lexingtonia'' dolabelloides, 
``Fusconaia'' barnesiana, and ``Pleurobema'' gibberum do not correspond 
to their currently assigned genera but form a closely related group. 
Williams et al. (2008, pp. 584-593) and Campbell and Lydeard (2012b, 
pp. 30, 34) picked the next available genus name for dolabelloides, 
which appears to be Pleuronaia (Frierson 1927). Based on this latest 
information, we currently consider Pleuronaia to be the most 
appropriate generic name for the slabside pearlymussel.
    The following description, biology, and life history of the 
slabside pearlymussel is taken from data summarized in Parmalee and 
Bogan (1998, pp. 150-152). The slabside pearlymussel is a moderately 
sized mussel that reaches about 9 cm (3.5 in) in length. The shape of 
the shell is subtriangular, and the very solid, heavy valves are 
moderately inflated. Shell texture is smooth and somewhat shiny in 
young specimens, becoming duller with age. Shell color is greenish 
yellow, becoming brownish with age, with a few broken green rays or 
blotches, particularly in young individuals. Internally, the 
pseudocardinal teeth are triangular or blade-like in shape. The lateral 
teeth are slightly curved, with two in the left valve and one in the 
right valve. The color of the nacre is white, or rarely, straw-colored.

Habitat and Life History

    General life history information for the slabside pearlymussel is 
similar to that given for the fluted kidneyshell above. Samples from 
approximately 150 shells of the slabside pearlymussel from the North 
Fork Holston River were thin-sectioned for age determination. The 
maximum age exceeded 40 years (Grobler et al. 2005, p. 65).
    The slabside pearlymussel utilizes all four gills as a marsupium 
for its glochidia. It is thought to have a spring or early summer 
fertilization period with the glochidia being released during the late 
summer in the form of conglutinates. Slabside pearlymussel 
conglutinates have not been described. The slabside pearlymussel's host 
fishes include 11 species of minnows (popeye shiner, Notropis ariommus; 
rosyface shiner, N. rubellus; saffron shiner, N. rubricroceus; silver 
shiner, N. photogenis; telescope shiner, N. telescopus; Tennessee 
shiner, N. leuciodus; whitetail shiner, Cyprinella galactura; striped 
shiner, Luxilus chrysocephalus; warpaint shiner, L. coccogenis; white 
shiner, L. albeolus; and eastern blacknose dace, Rhinichthys atratulus) 
(Kitchel 1985 and Neves 1991 in Parmalee and Bogan 1998, pp. 150-152; 
Jones and Neves 2002, pp. 18-20).
    The slabside pearlymussel is primarily a large creek to large river 
species, inhabiting sand, fine gravel, and cobble substrates in 
relatively shallow riffles and shoals with moderate current (Parmalee 
and Bogan 1998, p. 152; Williams et al. 2008, p. 590). This species 
requires flowing, well-oxygenated waters to thrive.

Historical Range and Distribution

    Historically, the slabside pearlymussel occurred in the lower 
Cumberland River mainstem from the vicinity of the Kentucky State line 
downstream to the the Caney Fork River, Tennessee, and in the Tennessee 
River mainstem from eastern Tennessee to western Tennessee. Records are 
known from two Cumberland River tributaries, the Caney Fork [TN] and 
Red Rivers [KY, TN]. In addition, it is known from 30 Tennessee River 
system tributaries, including the South Fork Powell River [VA], Powell 
River [TN, VA], Puckell Creek [VA], Clinch River [TN, VA], North Fork 
Holston River [TN, VA], Big Moccasin Creek [VA], Middle Fork Holston 
River [VA], South Fork Holston River [TN], Holston River [TN], 
Nolichucky River [TN], West Prong Little Pigeon River [TN], French 
Broad River [TN], Tellico River [TN], Little Tennessee River [TN], 
Hiwassee River [TN], Sequatchie River [TN],

[[Page 60811]]

Larkin Fork [AL], Estill Fork [AL], Hurricane Creek [AL], Paint Rock 
River [AL], Flint River [AL], Flint Creek [AL], Limestone Creek [AL], 
Elk River [AL, TN], Sugar Creek [AL], Bear Creek [AL, MS], North Fork 
Creek [TN], Big Rock Creek [TN], Buffalo River [TN], and Duck River 
[TN] (Gordon and Layzer 1989, entire; Winston and Neves 1997, entire; 
Parmalee and Bogan 1998, pp. 150-152). The slabside pearlymussel's 
known historical and current occurrences, by water body and county, are 
shown in Table 2 below.

                 Table 2--Known Historical and Current Occurrences for the Slabside Pearlymussel
----------------------------------------------------------------------------------------------------------------
          Water body                 Drainage             County        State         Historical or current
----------------------------------------------------------------------------------------------------------------
Cumberland River.............  Cumberland..........  Davidson, Smith  TN        Historical.
Caney Fork River.............  Cumberland..........  ?..............  TN        Historical.
Red River....................  Cumberland..........  Logan..........  KY        Historical.
Red River....................  Cumberland..........  ?..............  TN        Historical.
South Fork Powell River......  Tennessee...........  Wise...........  VA        Historical.
Powell River.................  Tennessee...........  Claiborne......  TN        Historical.
Powell River.................  Tennessee...........  Hancock........  TN        Historical and Current.
Powell River.................  Tennessee...........  Lee............  VA        Historical and Current.
Puckell Creek................  Tennessee...........  Lee............  VA        Historical.
Clinch River.................  Tennessee...........  Hancock........  TN        Historical and Current.
Clinch River.................  Tennessee...........  Anderson,        TN        Historical.
                                                      Campbell,
                                                      Claiborne,
                                                      Knox.
Clinch River.................  Tennessee...........  Russell, Scott,  VA        Historical and Current.
                                                      Tazewell, Wise.
North Fork Holston River.....  Tennessee...........  Hawkins,         TN        Historical.
                                                      Sullivan.
North Fork Holston River.....  Tennessee...........  Bland, Scott,    VA        Historical and Current.
                                                      Smyth,
                                                      Washington.
Big Moccasin Creek...........  Tennessee...........  Russell, Scott.  VA        Historical and Current.
Middle Fork Holston River....  Tennessee...........  Smyth,           VA        Historical and Current.
                                                      Washington,
                                                      Wythe.
South Fork Holston River.....  Tennessee...........  Sullivan.......  TN        Historical.
Holston River................  Tennessee...........  ?..............  TN        Historical.
French Broad River...........  Tennessee...........  Sevier.........  TN        Historical.
Tennessee River..............  Tennessee...........  Colbert,         AL        Historical.
                                                      Jackson,
                                                      Lauderdale.
Tennessee River..............  Tennessee...........  Hamilton,        TN        Historical.
                                                      Hardin, Knox,
                                                      Meigs, Rhea.
Nolichucky River.............  Tennessee...........  Cocke, Greene,   TN        Historical and Current.
                                                      Hamblen.
West Prong Little Pigeon       Tennessee...........  Sevier.........  TN        Historical.
 River.
Tellico River................  Tennessee...........  Monroe.........  TN        Historical.
Little Tennessee River.......  Tennessee...........  Monroe.........  TN        Historical.
Hiwassee River...............  Tennessee...........  Polk...........  TN        Historical and Current.
Sequatchie River.............  Tennessee...........  Sequatchie.....  TN        Historical and Current.
Larkin Fork..................  Tennessee...........  Jackson........  AL        Historical and Current.
Estill Fork..................  Tennessee...........  Jackson........  AL        Historical and Current.
Hurricane Creek..............  Tennessee...........  Jackson........  AL        Historical and Current.
Paint Rock River.............  Tennessee...........  Jackson,         AL        Historical and Current.
                                                      Madison,
                                                      Marshall.
Flint River..................  Tennessee...........  Madison........  AL        Historical.
Flint Creek..................  Tennessee...........  Morgan.........  AL        Historical.
Limestone Creek..............  Tennessee...........  Limestone......  AL        Historical.
Elk River....................  Tennessee...........  Limestone......  AL        Historical and Current.
Elk River....................  Tennessee...........  Lincoln........  TN        Historical and Current.
Elk River....................  Tennessee...........  Coffee,          TN        Historical.
                                                      Franklin,
                                                      Moore.
Sugar Creek..................  Tennessee...........  Limestone......  AL        Historical.
Bear Creek...................  Tennessee...........  Franklin.......  AL        Historical and Current.
Bear Creek...................  Tennessee...........  Tishomingo.....  MS        Historical and Current.
Duck River...................  Tennessee...........  Bedford,         TN        Historical and Current.
                                                      Hickman,
                                                      Marshall,
                                                      Maury.
Duck River...................  Tennessee...........  Coffee.........  TN        Historical.
North Fork Creek.............  Tennessee...........  Bedford........  TN        Historical.
Big Rock Creek...............  Tennessee...........  Marshall.......  TN        Historical.
Buffalo River................  Tennessee...........  Humphreys,       TN        Historical and Current.
                                                      Perry.
Buffalo River................  Tennessee...........  Lewis..........  TN        Historical.
----------------------------------------------------------------------------------------------------------------

    Based on collections made in the early 1900s, the slabside 
pearlymussel was historically fairly widespread and common in many 
Cumberlandian Region streams. However, its decline in certain streams 
may have begun before European colonization. The slabside pearlymussel 
was considered rare by mussel experts as early as 1970 (Stansbery 1971, 
p.13), which represents the first attempt to compile such a list. The 
extirpation of this species from numerous streams within its historical 
range indicates that substantial population losses and range reductions 
have occurred.

Current Range and Distribution

    In this document, populations of the slabside pearlymussel are 
generally considered extant (current) if live individuals or fresh dead 
specimens have been collected since circa 1980. This criterion (circa 
1980) was chosen because a large number of collections were conducted 
in the 1980s in the Cumberland and Tennessee River systems and due to 
the longevity of these species (40-55 years), they are still thought to 
occur in these areas.
    Some of the historical occurences have not been surveyed since the 
1980s. Based on this criterion, extant populations remain in the Powell 
River [TN, VA], Clinch River [TN, VA], North Fork Holston River [VA], 
Nolichucky River [TN], Big Moccasin Creek [VA], Middle Fork Holston 
River [VA], Hiwassee River [TN], Sequatchie River [TN], Paint Rock 
River [AL], Larkin Fork [AL], Estill Fork [AL], Hurricane Creek [AL], 
Elk River [AL, TN], Buffalo River [TN], Duck River [TN], and Bear Creek

[[Page 60812]]

[AL, MS] (see Table 2). Where two or more stream populations occur 
contiguously with no absolute barriers (e.g., large impoundments) or 
long reaches of unoccupied habitat, they are considered to represent a 
single population segment. The Paint Rock River system (including 
Larkin Fork, Estill Fork, and Hurricane Creek) is considered a single 
population segment or cluster but it occurs only in the lower mile or 
so of the three tributary streams. Thus, we consider 13 of 30 
populations of the slabside pearlymussel to be extant. The slabside 
pearlymussel has been eliminated from more than 50 percent of streams 
from which it was historically known.
    The extant occurrences in the Tennessee River system represent 11 
isolated populations. Population size data gathered during the past two 
decades indicate that the slabside pearlymussel is rare (experienced 
surveyors may find four or fewer specimens per site of occurrence) in 
about half of its extant populations. Only a few individuals have been 
found in the Powell River since 1988; therefore, this population is 
considered extremely rare (Ahlstedt et al. 2005, p. 9). In 2009, 4 
individuals were collected in the Powell River (Johnson 2010, p. 39). A 
single live individual was found in 2006 in Big Moccasin Creek, 
Virginia (Ostby et al. 2006, p. 3). The slabside pearlymussel is 
uncommon to rare in the Clinch River, with only a few individuals found 
per effort (Ahlstedt et al. 2005, p. 8). Eckert and Pinder (2010, pp. 
23-30) collected 1 individual in quantitative samples and 5 individuals 
in semi-quantitative samples in the Clinch River at Cleveland Island in 
2008, and 2 individuals in quantitative samples and 13 individuals in 
semi-quantitative samples in the Clinch River at Cleveland Island in 
2002. In 2005, approximately 20 individuals were found near Harms Mill 
(one of five sites surveyed) in the Elk River, Tennessee, and 13 
individuals (at two of five survey sites, spanning approximately 48 rkm 
(30 rmi)) were found in 2008 (Howard 2009, pers. comm.; Tennessee 
Valley Authority (TVA) 2009, p. 59). In 2002, one live individual was 
found in the Hiwassee River (Ahlstedt 2003, p. 3). The slabside 
pearlymussel was last found in the Sequatchie River 2 miles north of 
Dunlap, Tennessee, in 1980 (Hatcher and Ahlstedt 1982, p. 9). A small 
population is limited to Bear Creek in Mississippi, its only occurrence 
in that State (Jones 2012, pers. comm.). In 2009, TVA collected 9 
individuals at one site in Bear Creek (TVA 2010, p. 69). This 
population is recruiting as evidenced by collection of fresh dead 
juvenile shells in 2011 (Johnson 2011, pers. comm.). Given its 
longevity, small populations of this long-lived species may persist for 
decades despite total recruitment failure. The species has undergone 
decline in the North and Middle Forks of the Holston River (Jones and 
Neves 2005, pp. 8-9). This is especially true for the North Fork, where 
the species has been nearly eliminated (Hanlon 2006, unpub. data). The 
cause for the observed die-offs is unknown (Jones and Neves 2007, p. 
479). Ostby et al. (2010, pp. 16-20) observed 8 individuals in 
qualitative surveys at one site, but did not observe the species in 
quantitative surveys in the Upper North Fork Holston River. Slabside 
pearlymussels have declined at 3 of 4 survey sites on the Middle Fork 
Holston River (Henley 2011, pers. comm.). A single valve of a fresh 
dead specimen was found in the Nolichucky River in 2011 (Dinkins 2010b, 
p. 2-1). In 2011, TVA collected one live individual in the Buffalo 
River (Wales 2012, pers. comm.).
    The Duck and Paint Rock Rivers appear to have the best populations 
remaining rangewide based on population size and the evidence of recent 
recruitment. The slabside pearlymussel is found at numerous sites in 
the Duck River within a 64-rkm (40-rmi) reach, and is found at numerous 
sites within a 72-rkm (45-rmi) reach of the Paint Rock River (Ahlstedt 
et al. 2004, p. 84; Fobian et al. 2008, pp. 15-16). A 2010 quantitative 
survey of the Duck River found the slabside pearlymussel present but 
rare at 4 of 6 sites sampled (Hubbs et al. 2011, pp. 19-25).

Population Estimates and Status

    A recent study of major population centers concluded that all 
populations of the species were fairly similar in genetic structure 
(Grobler et al. 2005, p. 1). However, the population in the Duck River 
was deemed relatively distinct enough from those in the middle (i.e., 
Paint Rock River) and upper (i.e., Clinch, North and Middle Forks 
Holston Rivers) Tennessee River system to warrant recognition as a 
distinct management unit.
    Current status information for most of the 13 extant populations is 
available from recent periodic sampling efforts (sometimes annually) 
and other field studies. Comprehensive surveys have taken place in the 
Middle and North Forks Holston River, Paint Rock River, and Duck River 
in the past several years. Based on this information, the overall 
population of the slabside pearlymussel appears to be declining 
rangewide, and the species remains in relatively good numbers and 
appears viable in just two streams (Duck and Paint Rock Rivers). Two of 
the four largest populations in the mid-1990s have undergone drastic 
recent declines (i.e., North and Middle Forks Holston Rivers), 
especially in the North Fork. Most of the other populations are of 
questionable viability and may be on the verge of extirpation (e.g., 
Powell and Hiwassee Rivers; Big Moccasin Creek).
    The slabside pearlymussel was considered threatened by Williams et 
al. (1993, p. 13), but two decades later is considered endangered in a 
reassessment of the North American mussel fauna by the Endangered 
Species Committee of the American Fisheries Society (Butler 2012, pers. 
comm.). The slabside pearlymussel is listed as a species of Greatest 
Conservation Need (GCN) in the Alabama, Mississippi, Tennessee, and 
Virginia State Wildlife Action Plans (Alabama Department of 
Conservation and Natural Resources, Division of Wildlife and Freshwater 
Fisheries, 2005; KDFWR 2005; Mississippi Department of Wildlife, 
Fisheries and Parks, 2005; TWRA 2005; VDGIF 2005).

Summary of Factors Affecting the Species

    Section 4 of the Act, and its implementing regulations at 50 CFR 
part 424, set forth the procedures for adding species to the Federal 
Lists of Endangered and Threatened Wildlife and Plants. Under section 
4(a)(1) of the Act, we may list a species based on any of the following 
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; and (E) other natural or manmade factors affecting its 
continued existence. Listing actions may be warranted based on any of 
the above factors, singly or in combination. Each of these factors is 
discussed below.

A. The Present or Threatened Destruction, Modification, or Curtailment 
of Its Habitat or Range

    The decline of the fluted kidneyshell and slabside pearlymussel in 
the Cumberlandian Region and other mussel species in the eastern United 
States is primarily the result of habitat loss and degradation. Chief 
among the causes of decline are impoundments, gravel and coal mining, 
sedimentation, water pollution, and stream channel alterations (Neves 
1993, pp. 4-5;

[[Page 60813]]

Williams et al. 1993, p. 7; Neves et al. 1997, pp. 60-78).
Impoundments
    Impoundments result in the dramatic modification of riffle and 
shoal habitats and the resulting loss of mussel resources, especially 
in larger rivers. Impoundment impacts are most profound in riffle and 
shoal areas, which harbor the largest assemblages of mussel species, 
including the fluted kidneyshell and slabside pearlymussel. Mussels are 
relatively immobile and, therefore, require a stable substrate to 
survive and reproduce, and are particularly susceptible to channel 
instability (Neves et al. 1997, p. 23) and alteration in the dynamic 
processes involved in maintaining stream stability. Dams interrupt most 
of a river's ecological processes by modifying flood pulses; 
controlling impounded water elevations; altering water flow, sediments, 
nutrients, energy inputs, and outputs; increasing depth; decreasing 
habitat heterogeneity; and decreasing bottom stability due to 
subsequent sedimentation. In addition, dams can also seriously alter 
downstream water quality and riverine habitat and negatively impact 
tailwater mussel populations. These changes include thermal alterations 
immediately below dams; changes in channel characteristics, habitat 
availability, and flow regime; daily discharge fluctuations; increased 
silt loads; and altered host fish communities. For these above-
mentioned reasons, the reproductive process of riverine mussels is 
generally disrupted by impoundments, making them unable to successfully 
reproduce and recruit under reservoir conditions. Coldwater releases 
from large non-navigational dams and scouring of the river bed from 
highly fluctuating, turbulent tailwater flows have also been implicated 
in the demise of mussel faunas (see critical habitat descriptions for 
Units FK19 and FK20, below).
    The damming of rivers has been a major factor contributing to the 
demise of mussels (Bogan 1993, p. 604). Dams eliminate or reduce river 
flow within impounded areas, trap silts and cause sediment deposition, 
alter water temperature and dissolved oxygen levels, change downstream 
water flow and quality, affect normal flood patterns, and block 
upstream and downstream movement of mussels and their host fishes 
(Bogan 1993, p. 604; Vaughn and Taylor 1999, pp. 915-917; Watters 1999, 
pp. 261-264; McAllister et al. 2000, p. iii; Marcinek et al. 2005, pp. 
20-21). Below dams, mollusk declines are associated with changes and 
fluctuation in flow regime, scouring and erosion, reduced dissolved 
oxygen levels, reduced food availability, water temperature alteration, 
and changes in resident fish assemblages (Williams et al. 1993, p. 7; 
Neves et al. 1997, pp. 63-64; Watters 1999, pp. 261-264; Marcinek et 
al. 2005, pp. 20-21; Moles and Layzer 2008, p. 220). Because rivers are 
linear systems, these alterations can cause mussel declines for many 
miles below the dam (Moles and Layzer 2008, p. 220; Vaughn and Taylor 
1999, p. 916).
    Population losses due to impoundments have probably contributed 
more to the decline of the fluted kidneyshell, slabside pearlymussel, 
and other Cumberlandian Region mussels than has any other single 
factor. The majority of the Cumberland and Tennessee River mainstems 
and many of their largest tributaries are now impounded, and therefore, 
are unsuitable for Cumberlandian Region mussels. For example, 
approximately 90 percent of the 904-rkm (562-rmi) length of the 
Cumberland River downstream of Cumberland Falls is either impounded 
(three locks and dams and Wolf Creek Dam) or otherwise adversely 
impacted by coldwater discharges from Wolf Creek Dam. Other major U.S. 
Army Corps of Engineers (Corps) impoundments on Cumberland River 
tributaries (e.g., Obey River, Caney Fork) have inundated over 161 rkm 
(100 rmi) of riverine habitat for the fluted kidneyshell and the 
slabside pearlymussel. Layzer et al. (1993, p. 68) reported that 37 of 
the 60 mussel species present in the Caney Fork River pre-impoundment 
have been extirpated. By 1971, approximately 3,700 rkm (2,300 rmi) 
(about 20 percent) of the Tennessee River and its tributaries with 
drainage areas of 65 square rkm (25 square rmi) or greater were 
impounded by the TVA (TVA 1971, p. 5). The subsequent completion of 
additional major impoundments on tributary streams (e.g., Duck River in 
1976, Little Tennessee River in 1979) significantly increased the total 
river kilometers (miles) impounded behind the 36 major dams in the 
Tennessee River system.
    Given projected population increases and the need for municipal 
water supply, other proposals for small impoundment construction are 
likely in the future within the Cumberland and Tennessee River systems.
Mining and Commercial Navigation
    Instream gravel mining has been implicated in the destruction of 
mussel populations. Negative impacts associated with gravel mining 
include stream channel modifications (e.g., altered habitat, disrupted 
flow patterns, sediment transport), water quality modifications (e.g., 
increased turbidity, reduced light penetration, increased temperature), 
macroinvertebrate population changes (e.g., elimination, habitat 
disruption, increased sedimentation), and changes in fish populations 
(e.g., impacts to spawning and nursery habitat, food web disruptions) 
(Kanehl and Lyons 1992, pp. 26-27).
    Gravel mining activities negatively impact the habitat of the 
fluted kidneyshell in Buck Creek, one of the few remaining populations 
of this species in the entire Cumberland River system. Gravel mining 
activities also negatively impact the habitat of the slabside 
pearlymussel in the Powell and Elk Rivers in the Tennessee River 
system.
    Channel modification for commercial navigation has been shown to 
increase flood heights (Belt 1975, p. 684), partly as a result of an 
increase in stream bed slope (Hubbard et al. 1993, p. 137). Flood 
events are exacerbated, conveying large quantities of sediment, 
potentially with adsorbed contaminants, into streams. Channel 
maintenance often results in increased turbidity and sedimentation that 
often smothers mussels (Stansbery 1970, p. 10).
    Heavy metal-rich drainage from coal mining and associated 
sedimentation has adversely impacted upper Cumberland and Tennessee 
River system streams with historically diverse mussel faunas. Strip 
mining continues to threaten mussel habitats in coal field drainages of 
the Cumberland Plateau, including streams harboring small fluted 
kidneyshell populations (e.g., Horse Lick Creek, Little South Fork, 
Powell River, Indian Creek). Portions of the upper Tennessee River 
system are also influenced by coal mining activities. Powell River 
mussel populations were inversely correlated with coal fines in the 
substrate; when coal fines were present, decreased filtration times and 
increased movements were noted in laboratory-held mussels (Kitchel et 
al. 1981, p. 25). In a quantitative study in the Powell River, a 
decline of federally listed mussels and the long-term decrease in 
overall species composition since about 1980 was attributed to general 
stream degradation due primarily to coal mining activities in the 
headwaters (Ahlstedt and Tuberville 1997, pp. 74-76). Numerous gray-
water and black-water spill events have been documented in the Powell 
and Clinch River drainages over the past several years. The habitats of 
Fluted

[[Page 60814]]

kidneyshell, slabside pearlymussel, and other mussels in the Clinch and 
Powell rivers are increasingly being threatened by coal mining 
activities.
Oil and Natural Gas Development
    Oil and natural gas resources are present in some of the watersheds 
that are known or historically were known to support the fluted 
kidneyshell and slabside pearlymussel, including the Clinch, Powell, 
and Big South Fork Rivers. Exploration and extraction of these energy 
resources has the potential to result in increased siltation, a changed 
hydrograph (flow regime), and altered water quantity and quality even 
at a distance from the mine or well field. Although oil and natural gas 
extraction generally occurs away from the river, extensive road and 
pipeline networks are required to construct and maintain wells and 
transport the extracted resources. These road and pipeline networks 
frequently cross or occur near tributaries, contributing sediment to 
the receiving waterway. In addition, the construction and operation of 
wells may result in the illegal discharge of chemical contaminants and 
subsurface minerals.
Sedimentation
    Sedimentation is one of the most significant pollution problems for 
aquatic organisms (Waters 1995, pp. 2-3), and has been determined to be 
a major factor in mussel declines (Ellis 1936, pp. 39-40). Sources of 
silt and sediment include poorly designed and executed timber 
harvesting operations and associated activities; complete clearing of 
riparian vegetation for agricultural, silvicultural, or other purposes; 
and those construction, mining, and other practices that allow exposed 
earth to enter streams. Agricultural activities, specifically an 
increase in cattle grazing and the resultant nutrient enrichment and 
loss of riparian vegetation along the stream, are responsible for much 
of the sediment (Fraley and Ahlstedt 2000, p. 193; Hanlon et al. 2009, 
pp. 11-12).
    Heavy sediment loads can destroy mussel habitat, resulting in a 
corresponding shift in mussel fauna (Brim Box and Mossa 1999, p. 100). 
Excessive sedimentation can lead to rapid changes in stream channel 
position, channel shape, and bed elevation (Brim Box and Mossa 1999, p. 
102). Sedimentation has also been shown to impair the filter feeding 
ability of mussels, and high amounts of suspended sediments can dilute 
their food source (Dennis 1984, p. 212). We will describe the 
detrimental actions of sedimentation in Factor E, below.
Chemical Contaminants
    Chemical contaminants are ubiquitous throughout the environment and 
are considered a major threat in the decline of mussel species (Richter 
et al. 1997, p. 1081; Strayer et al. 2004, p. 436; Wang et al. 2007a, 
p. 2029; Cope et al. 2008, p. 451). Chemicals enter the environment 
through both point and nonpoint discharges including spills, industrial 
sources, municipal effluents, and agricultural runoff. These sources 
contribute organic compounds, heavy metals, pesticides, and a wide 
variety of newly emerging contaminants to the aquatic environment. As a 
result, water and sediment quality can be degraded to the extent that 
mussel habitats and populations are adversely impacted. We will 
describe the detrimental actions of chemicals in Factor E, below.
Other Stream Channel Alterations
    Other stream channel alterations that can impact mussel habitats 
include bridges, other road crossing structures, and activities that 
lower water tables (withdrawals). Culverts can act as barriers to fish 
passage (Wheeler et al. 2005, p. 149), particularly by increasing flow 
velocity (Warren and Pardew 1998, p. 637). Stream channels become 
destabilized when improperly designed culverts or bridges change the 
morphology and interrupt the transport of woody debris, substrate, and 
water (Wheeler et al. 2005, p. 152). Water withdrawals for irrigation, 
municipal, and industrial water supplies are an increasing concern. 
U.S. water consumption doubled from 1960 to 2000, and is likely to 
increase further (Naiman and Turner 2000, p. 960). Therefore, we 
anticipate road crossings, water withdrawals, and potential stream 
dewatering to be threats to the habitat of the fluted kidneyshell and 
slabside pearlymussel.
Summary of Factor A
    Habitat loss and degradation negatively impact the fluted 
kidneyshell and slabside pearlymussel. Severe degradation from 
impoundments, gravel and coal mining, oil and natural gas development, 
sedimentation, chemical contaminants, and stream channel alterations 
threaten the stream habitat and water quality on which these species 
depend. Contaminants associated with coal mining (metals, other 
dissolved solids), municipal effluents (bacteria, nutrients, 
pharmaceuticals), and agriculture (fertilizers, pesticides, herbicides, 
and animal waste) cause degradation of water quality and habitats 
through increased acidity and conductivity, instream oxygen 
deficiencies, excess nutrification, and excessive algal growths. 
Furthermore, these threats faced by the fluted kidneyshell and slabside 
pearlymussel are imminent; the result of ongoing projects that are 
expected to continue indefinitely, therefore perpetuating these 
impacts. As a result of the imminence of these threats, combined with 
the vulnerability of the remaining small, isolated populations to 
extirpation from natural and manmade threats, we have determined that 
the present or threatened destruction, modification, or curtailment of 
the habitat and range of these species represents a threat to both the 
fluted kidneyshell and slabside pearlymussel.

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

    The fluted kidneyshell and slabside pearlymussel are not 
commercially valuable species, but may be increasingly sought by 
collectors, due to their increasing rarity. Although scientific 
collecting is not thought to represent a significant threat, localized 
populations could become impacted, and possibly extirpated, by 
overcollecting, particularly if regulations governing collection 
activity (currently scientific collection is controlled by the States 
through the issuance of collection permits; see Factor D below) are not 
enforced.
    In summary, the fluted kidneyshell and slabside pearlymussel are 
not commercially utilized but might be increasingly sought for 
scientific or educational purposes as their rarity becomes known. We do 
not consider overutilization for commercial, recreational, scientific, 
or educational purposes to be a threat to either species now or likely 
to become a threat in the future.

C. Disease or Predation

    Little is known about diseases in mussels (Grizzle and Brunner 
2007, p. 6). Several mussel dieoffs have been documented during the 
past 20 years (Neves 1987, pp. 8-11). Although the ultimate cause is 
unknown, some researchers believe that disease may be a factor. Warren 
and Haag (2005, p. 1394) hypothesized that declines in the Little South 
Fork Cumberland River, Kentucky, mussel fauna, including the once 
abundant fluted kidneyshell population, may have been at least 
partially attributed to disease, but no definitive cause has been 
determined. We have no specific documentation indicating that disease 
poses a threat to slabside pearlymussel populations.

[[Page 60815]]

    Juvenile and adult mussels are prey items for some invertebrate 
predators and parasites (for example, nematodes and mites), and are 
prey for a few vertebrate species (for example, raccoons, muskrats, 
otters, and turtles) (Hart and Fuller 1974, pp. 225-240). Mussel 
parasites include water mites, trematodes, oligochaetes, leeches, 
copepods, bacteria, and protozoa (Grizzle and Brunner 2007, p. 6). 
Generally, parasites are not suspected of being a major limiting factor 
(Oesch 1984, p. 16); however, Gangloff et al. (2008, pp. 28-30) found 
that reproductive output and physiological condition were negatively 
correlated with mite and trematodes abundance, respectively. Stressors 
that reduce fitness may make mussels more susceptible to parasites 
(Butler 2007, p. 90).
    Muskrat predation on the fluted kidneyshell represents a localized 
threat, as determined by Neves and Odum (1989, entire) in the upper 
North Fork Holston River in Virginia. They concluded that muskrat 
predation could limit the recovery potential of endangered mussel 
species or contribute to the local extirpation of already depleted 
mussel populations. Although other mammals (e.g., raccoon, mink) 
occasionally feed on mussels, the threat from these predators is not 
considered to be significant. Predation does occur, but it is 
considered to be a normal aspect of the species' population dynamics.
    In summary, there is little information on disease in mussels, and 
disease is not currently considered to be a threat to the fluted 
kidneyshell or slabside pearlymussel and it is not likely to become so 
in the future. Although predation does occur and impacts local 
populations, we conclude that predation is not a threat to these 
species as a whole or likely to become so in the future.

D. The Inadequacy of Existing Regulatory Mechanisms

    The objective of the Federal Water Pollution Control Act, commonly 
referred to as the Clean Water Act (CWA) (33 U.S.C. 1251 et seq.), is 
to restore and maintain the chemical, physical, and biological 
integrity of the nation's waters by preventing point and nonpoint 
pollution sources. The CWA has a stated goal that ``* * * wherever 
attainable, an interim goal of water quality which provides for the 
protection and propagation of fish, shellfish, and wildlife and 
provides for recreation in and on the water be achieved by July 1, 
1983.'' States are responsible for setting and implementing water 
quality standards that align with the requirements of the CWA. Overall, 
implementation of the CWA could benefit both mussel species through the 
point and nonpoint programs.
    Nonpoint source (NPS) pollution comes from many diffuse sources, 
unlike pollution from industrial and sewage treatment plants. NPS 
pollution is caused by rainfall or snowmelt moving over and through the 
ground. As the runoff moves, it transports natural and human-made 
pollutants to lakes, rivers, wetlands, coastal waters and ground 
waters. States report that nonpoint source pollution is the leading 
remaining cause of water quality problems. The effects of nonpoint 
source pollutants on specific waters vary and may not always be fully 
assessed. However, these pollutants have harmful effects on fisheries 
and wildlife (https://www.epa.gov/owow_keep/NPS/whatis.html).
    Sources of NPS pollution within the watersheds occupied by both 
mussels include agriculture, clearing of riparian vegetation, 
urbanization, road construction, and other practices that allow bare 
earth to enter streams. The Service has no information concerning the 
implementation of the CWA regarding NPS pollution specific to 
protection of both mussels. However, insufficient implementation could 
become a threat to both mussel species if they continue to decline in 
numbers.
    The fluted kidneyshell and slabside pearlymussel continue to 
decline due to the effects of habitat destruction, poor water quality, 
contaminants, and other factors. However, there is no specific 
information known about the sensitivity of these mussels to common 
point source pollutants like industrial and municipal pollutants and 
very little information on other freshwater mussels. Because there is 
very little information known about water quality parameters necessary 
to fully protect freshwater mussels, such as the fluted kidneyshell and 
slabside pearlymussel, it is difficult to determine whether the CWA is 
adequately addressing the habitat and water quality threats to these 
species. However, given that a goal of the CWA is to establish water 
quality standards that protect shellfish and given that documented 
declines of these mussel species still continue due to poor water 
quality and other factors, we take a conservative approach in favor of 
the species and conclude that the CWA has been insufficient to 
significantly reduce or remove the threats to the fluted kidneyshell 
and slabside pearlymussel. We invite public comment on this matter, and 
solicit information especially regarding water quality data that may be 
helpful in determining the water quality parameters necessary for these 
species' survival (see Information Requested, item 4).
Summary of Factor D
    In summary, the CWA has a stated goal to establish water quality 
standards that protect aquatic species, including the fluted 
kidneyshell and slabside pearlymussel. However, the CWA has generally 
been insufficient at protecting mussels, and adequate water quality 
criteria that are protective of all life stages, particularly glochidia 
and juveniles, may not be established. Little information is known 
about specific sensitivities of mussels to various pollutants, but both 
species continue to decline due to the effects of habitat destruction, 
poor water quality, contaminants, and other factors. Based on our 
analysis of the best available scientific and commercial data, we 
conclude that the current implementation of the provisions under the 
CWA to protect water quality for aquatic species is inadequate to 
reduce or remove threats to the fluted kidneyshell and slabside 
pearlymussel throughout all of their range.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

Altered Temperature Regimes
    Natural temperature regimes can be altered by impoundments, water 
releases from dams, industrial and municipal effluents, and changes in 
riparian habitat. Critical thermal limits for survival and normal 
functioning of many mussel species are unknown. High temperatures can 
reduce dissolved oxygen concentrations in the water, which slows 
growth, reduces glycogen stores, impairs respiration, and may inhibit 
reproduction (Hart and Fuller 1974, pp. 240-241). Low temperatures can 
significantly delay or prevent metamorphosis (Watters and O'Dee 1999, 
pp. 454-455). Water temperature increases have been documented to 
shorten the period of glochidial encystment, reduce the speed in which 
they turn upright, increase oxygen consumption, and slow burrowing and 
movement responses (Hart and Fuller 1974, pp. 240-241; Bartsch et al. 
2000, p. 237; Watters et al. 2001, p. 546; Schwalb and Pusch 2007, pp. 
264-265). Several studies have documented the influence of temperature 
on the timing of aspects of mussel reproduction (for example, Gray et 
al. 2002, p. 156; Allen et al. 2007, p. 85; Steingraeber et al. 2007, 
pp. 303-309). Peak glochidial

[[Page 60816]]

releases are associated with water temperature thresholds that can be 
thermal minimums or thermal maximums, depending on the species (Watters 
and O'Dee 2000, p. 136). Abnormal temperature changes may cause 
particular problems to mussels whose reproductive cycles may be linked 
to fish reproductive cycles Young and Williams 1984, entire).
Chemical Contaminants
    Chemical spills can be especially devastating to mussels because 
they may result in exposure of a relatively immobile species to 
extremely elevated contaminant concentrations that far exceed toxic 
levels and any water quality standards that might be in effect. Some 
notable spills that released large quantities of highly concentrated 
chemicals resulting in mortality to mussels and host fish include a 
kill on the Clinch River at Carbo, Virginia, from a power plant 
alkaline fly ash pond spill in 1967, and a sulfuric acid spill in 1970 
(Crossman et al. 1973, p. 6). Approximately 18,000 mussels of several 
species, including the fluted kidneyshell and 750 individuals from 
three endangered mussel species (tan riffleshell, Epioblasma florentina 
walkeri; purple bean, Villosa perpurpurea; and rough rabbitsfoot, 
Quadrula cylindrica strigillata), were eliminated from the upper Clinch 
River near Cedar Bluff, Virginia, in 1998, when an overturned tanker 
truck released approximately 6,100 liters (1,600 gallons) of a chemical 
used in rubber manufacturing (Jones et al. 2001, p. 20; Schmerfeld 
2006, p. 12). These are not the only instances where chemical spills 
have resulted in the loss of high numbers of mussels (Neves 1991, p. 
252; Jones et al. 2001, p. 20; Brown et al. 2005, p. 1457; Schmerfeld 
2006, pp. 12-13), but are provided as examples of the serious threat 
chemical spills pose to mussel species, such as the fluted kidneyshell 
and slabside pearlymussel.
    Cope et al. (2008, p. 451) evaluated the pathways of exposure to 
environmental pollutants for all four mollusk life stages (free 
glochidia, encysted glochidia, juveniles, and adults) and found that 
each life stage has both common and unique characteristics that 
contribute to observed differences in contaminant exposure and 
sensitivity. Very little is known of the potential mechanisms and 
consequences of waterborne toxicants on sperm viability. However, 
Watters (2011) demonstrated that the spermatozeugmata (sperm ball) 
produced and released by male mussels are sensitive to varying levels 
of salinity. When exposed to high enough salinity levels, the 
spermatozeugmata disassociate and can be rendered nonviable if they 
disassociate prior to entering a female mussel. This may pose yet 
another significant challenge for mussels to successfully fertilize 
eggs and promote recruitment if exposed to elevated salinity or 
conductivity levels in the ambient water column.
    In the female mollusk, the marsupial region of the gill currently 
is thought to be physiologically isolated from respiratory functions, 
and this isolation may provide some level of protection from 
contaminant interference with a female's ability to achieve 
fertilization or brood glochidia (Cope et al. 2008, p. 454). A major 
exception to this assertion is with chemicals that act directly on the 
neuroendocrine pathways controlling reproduction (see discussion 
below). Nutritional and ionic exchange is possible between a brooding 
female and her glochidia, providing a route for chemicals (accumulated 
or waterborne) to disrupt biochemical and physiological pathways (such 
as maternal calcium transport for construction of the glochidial 
shell).
    Juvenile mussels typically remain burrowed beneath the sediment 
surface for 2 to 4 years. Residence beneath the sediment surface 
necessitates deposit (pedal) feeding and a reliance on interstitial 
(pore) water for dissolved oxygen (Watters 2007, p. 56). The relative 
importance of juvenile fluted kidneyshell and slabside pearlymussel 
exposure to contaminants in overlying surface water, interstitial 
(pore) water, whole sediment, or food has not been adequately assessed. 
Exposure to contaminants from each of these routes varies with certain 
periods and environmental conditions (Cope et al. 2008, pp. 453, 457).
    The primary routes of exposure to contaminants for adult fluted 
kidneyshell and slabside pearlymussel are surface water, sediment, 
interstitial (pore) water, and diet; adults can be exposed when either 
partially or completely burrowed in the substrate (Cope et al. 2008, p. 
453). Adult mussels have some ability to detect certain toxicants in 
the water and close their valves to avoid exposure (Van Hassel and 
Farris 2007, p. 6). Adult mussel toxicity and relative sensitivity 
(exposure and uptake of toxicants) may be reduced at high rather than 
at low toxicant concentrations because uptake is affected by the 
prolonged or periodic toxicant avoidance responses (when the avoidance 
behavior can no longer be sustained for physiological reasons) (Cope et 
al. 2008, p. 454). Toxicity results based on low-level exposure of 
adults are similar to estimates for glochidia and juveniles for some 
toxicants (for example, copper). The duration of any toxicant avoidance 
response by an adult mussel is likely to be affected by several 
variables, such as species, age, shell thickness and gape, properties 
of the toxicant, and water temperature. There is a lack of information 
on toxicant response(s) specific to adult mussels (including the fluted 
kidneyshell and slabside pearlymussel), but results of tests using 
glochidia and juveniles may be valuable for protecting adults (Cope et 
al. 2008, p. 454).
    Exposure to lower concentrations of contaminants, more likely to be 
found in aquatic environments, can also adversely affect mussels and 
result in the decline of mussel species. Such concentrations may not be 
immediately lethal, but over time, can result in mortality, reduced 
filtration efficiency, reduced growth, decreased reproduction, changes 
in enzyme activity, and behavioral changes to all mussel life stages. 
Frequently, procedures that evaluate the `safe' concentration of an 
environmental contaminant (e.g., national water quality criteria) do 
not have data for mussel species or exclude data that is available for 
mussels (March et al. 2007, pp. 2066-2067, 2073).
    Current research is now focusing on the contaminant sensitivity of 
mussel glochidia and newly-released juvenile mussels (Goudreau et al. 
1993, pp. 219-222; Jacobson et al. 1997, p. 2390; Valenti et al. 2005, 
pp. 1244-1245; Valenti et al. 2006, pp. 2514-2517; March et al. 2007, 
pp. 2068-2073; Wang et al. 2007b, pp. 2041-2046) and juveniles 
(Augspurger et al. 2003, p. 2569; Bartsch et al. 2003, p. 2561; Mummert 
et al. 2003, p. 2549; Valenti et al. 2005, pp. 1244-1245; Valenti et 
al. 2006, pp. 2514-2517; March et al. 2007, pp. 2068-2073; Wang et al. 
2007b, pp. 2041-2046; Wang et al. 2007c, pp. 2053-2055) to such 
contaminants as ammonia, metals, chlorine, and pesticides.
    One chemical that is particularly toxic to early life stages of 
mussels is ammonia. Sources of ammonia include agriculture (animal 
feedlots and nitrogenous fertilizers), municipal wastewater treatment 
plants, and industrial waste (Augspurger et al. 2007, p. 2026) as well 
as precipitation and natural processes (i.e., decomposition of organic 
nitrogen) (Goudreau et al. 1993, p. 212; Hickey and Martin 1999, p. 44; 
Augspurger et al. 2003, p. 2569; Newton 2003, p. 1243). Therefore, 
ammonia is considered a limiting factor for survival and recovery of 
some mussel species

[[Page 60817]]

due to its ubiquity in aquatic environments and high level of toxicity, 
and because the highest concentrations typically occur within 
microhabitats inhabited by mussels (Augspurger et al. 2003, p. 2574). 
In addition, studies have shown that ammonia concentrations increase 
with increasing temperature and low flow conditions (Cherry et al. 
2005, p. 378; Cooper et al. 2005, p. 381), which may be exacerbated by 
the effects of climate change, and may cause ammonia to become more 
problematic for juvenile mussels.
    Mussels are also affected by heavy metals (Keller and Zam 1991, p. 
543) such as cadmium, chromium, copper, mercury, and zinc, which can 
negatively affect biological processes such as growth, filtration 
efficiency, enzyme activity, valve closure, and behavior (Keller and 
Zam 1991, p. 543; Naimo 1995, pp. 351-355; Jacobson et al. 1997, p. 
2390; Valenti et al. 2005, p. 1244). Heavy metals occur in industrial 
and wastewater effluents and are often a result of atmospheric 
deposition from industrial processes and incinerators. Glochidia and 
juvenile mussels have recently been studied to determine the acute and 
chronic toxicity of copper to these life stages (Wang et al. 2007b, pp. 
2036-2047; Wang et al. 2007c, pp. 2048-2056). The chronic values 
determined for copper for survival and growth of juveniles are below 
the Environmental Protection Agency (EPA) 1996 chronic water quality 
criterion for copper (Wang et al. 2007c, pp. 2052-2055). March (2007, 
pp. 2066 and 2073) identified that copper water quality criteria and 
modified State water quality standards may not be protective of 
mussels.
    Mercury is another heavy metal that has the potential to negatively 
affect mussel populations, and it is receiving attention due to its 
widespread distribution and potential to adversely impact the 
environment. Mercury has been detected throughout aquatic environments 
as a product of municipal and industrial waste and atmospheric 
deposition from coal burning plants. Valenti et al. (2005, p. 1242) 
determined that for rainbow mussel, Villosa iris, glochidia were more 
sensitive to mercury than juvenile mussels, and that reduced growth in 
juveniles is seen when observed concentrations are higher than EPA's 
criteria for mercury. Based on these data, we believe that EPA's water 
quality standards for mercury should be protective of juvenile mussels 
and glochidia, except in cases of illegal dumping, permit violations, 
or spills. However, impacts to mussels from mercury toxicity may be 
occurring in some streams. According to the National Summary Data 
reported by States to the EPA, 4,716 monitored waters do not meet EPA 
standards for mercury in the United States (https://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T, accessed 6/28/
2012). Acute mercury toxicity was determined to be the cause of 
extirpation of a diverse mussel fauna for a 112-rkm (70-rmi) portion of 
the North Fork Holston River (Brown et al. 2005, pp. 1455-1457).
    In addition to ammonia, agricultural sources of chemical 
contaminants include two broad categories that have the potential to 
adversely impact mussel species: nutrients and pesticides. Nutrients 
(such as nitrogen and phosphorus) can impact streams when their 
concentrations reach levels that cannot be assimilated, a condition 
known as over-enrichment. Nutrient over-enrichment is primarily a 
result of runoff from livestock farms, feedlots, and heavily fertilized 
row crops (Peterjohn and Correll 1984, p. 1471). Over-enriched 
conditions are exacerbated by low-flow conditions, such as those 
experienced during typical summer-season flows and that might occur 
with greater frequency and magnitude as a result of climate change. 
Bauer (1988, p. 244) found that excessive nitrogen concentrations can 
be detrimental to the adult pearl mussel (Margaritifera margaritifera), 
as was evident by the positive linear relationship between mortality 
and nitrate concentration. Also, a study of mussel life span and size 
(Bauer 1992, p. 425) showed a negative correlation between growth rate 
and eutrophication, and longevity was reduced as the concentration of 
nitrates increased. Nutrient over-enrichment can result in an increase 
in primary productivity, and the subsequent respiration depletes 
dissolved oxygen levels. This may be particularly detrimental to 
juvenile mussels, which inhabit the interstitial spaces in the 
substrate, where lower dissolved oxygen concentrations are more likely 
than on the sediment surface where adults tend to live (Sparks and 
Strayer 1998, pp. 132-133).
    Elevated concentrations of pesticide frequently occur in streams 
due to runoff, overspray application to row crops, and lack of adequate 
riparian buffers. Agricultural pesticide applications and the 
reproductive and early life stages of mussels often coincide in the 
spring and summer, and thus impacts to mussels due to pesticides may be 
increased (Bringolf et al. 2007c, p. 2094). Little is known regarding 
the impact of currently used pesticides to mussels even though some 
pesticides, such as glyphosate (e.g., Roundup\TM\), are used globally. 
Recent studies tested the toxicity of glyphosate, its formulations, and 
a surfactant (MON 0818) used in several glyphosate formulations, to 
early life stages of the fatmucket (Lampsilis siliquoidea) (Bringolf et 
al. 2007c, p. 2094). Studies conducted with juvenile mussels and 
glochidia determined that the surfactant (MON 0818) was the most toxic 
of the compounds tested and that fatmucket glochidia were the most 
sensitive of organisms tested to date (Bringolf et al. 2007c, p. 2094). 
Roundup\TM\), technical grade glyphosate isopropylamine salt, and 
isopropylamine were also acutely toxic to juveniles and glochidia 
(Bringolf et al. 2007c, p. 2097). The impacts of other pesticides 
including atrazine, chlorpyrifos, and permethrin on glochidia and 
juvenile life stages have also recently been studied (Bringolf et al. 
2007a, p. 2101). This study determined that chlorpyrifos was toxic to 
both fatmucket glochidia and juveniles (Bringolf et al. 2007a, p. 
2104). The above results indicate the potential toxicity of commonly 
applied pesticides and the threat to mussel species as a result of the 
widespread use of these pesticides. All of these pesticides are 
commonly used throughout the range of the fluted kidneyshell and 
slabside pearlymussel.
    Pharmaceutical chemicals used in commonly consumed drugs are 
increasingly found in surface waters downstream from municipal 
effluents. A recent nationwide study sampling 139 stream sites in 30 
States detected the presence of numerous pharmaceuticals, hormones, and 
other organic wastewater contaminants downstream from urban development 
and livestock production areas (Kolpin et al. 2002, pp. 1208-1210). 
Exposure to waterborne and, potentially to sediment, toxicant chemicals 
that act directly on the neuroendocrine pathways controlling 
reproduction can cause premature release of viable or nonviable 
glochidia. For example, the active ingredient in many human 
prescription anti-depressant drugs belonging to the class of selective 
serotonin reuptake inhibitors may exert negative reproductive effects 
on mussels because of their action on serotonin and other 
neuroendocrine pathways (Cope et al. 2008, pp. 455). These waterborne 
chemicals alter mussel behavior and influence successful attachment of 
glochidia on fish hosts and, therefore, may have population level 
implications for the fluted kidneyshell and slabside pearlymussel.
    This information indicates it is likely that chemical contaminants 
have contributed to declining fluted

[[Page 60818]]

kidneyshell and slabside pearlymussel populations, and will likely 
continue to be a threat to these species in the future. These threats 
result from spills that are immediately lethal to species, as well as 
chronic contaminant exposure, which results in death, reduced growth, 
or reduced reproduction of fluted kidneyshell and slabside 
pearlymussel.
Sedimentation
    Impacts resulting from sediments have been noted for many 
components of aquatic communities. For example, sediments have been 
shown to abrade or suffocate periphyton (organisms attached to 
underwater surfaces); affect respiration, growth, reproductive success, 
and behavior of aquatic insects and mussels; and affect fish growth, 
survival, and reproduction (Waters 1995, pp. 173-175). When in high 
silt environments, mussels may keep their valves closed more often, 
resulting in reduced feeding activity (Ellis 1936, p. 30).
    Increased turbidity from suspended sediment can reduce or eliminate 
juvenile mussel recruitment (Negus 1966, p. 525; Box and Mossa 1999, 
pp. 101-102). Many mussel species use visual cues to attract host 
fishes; such a reproductive strategy depends on clear water for 
success. For example, increased turbidity may impact the southern 
sandshell, Hamiota australis, life cycle by reducing the chance that a 
sight-feeding host fish will encounter the visual display of its 
superconglutinate lure (Haag et al. 1995, p. 475; Blalock-Herod et al. 
2002, p. 1885). If the superconglutinate is not encountered by a host 
within a short time period, the glochidia will become nonviable 
(O'Brien and Brim Box 1999, p. 133). Also, evidence suggests that 
conglutinates of the southern kidneyshell (another species of 
Ptychobranchus, P. jonesi), once released from the female mussel in an 
attempt to lure potential host fish, must adhere to hard surfaces in 
order to be seen by its fish host. If the surface becomes covered in 
fine sediments, the conglutinate cannot attach and is swept away 
(Hartfield and Hartfield 1996, p. 373).
Population Fragmentation and Isolation
    Population isolation prohibits the natural interchange of genetic 
material between populations, and small population size reduces the 
reservoir of genetic diversity within populations, which can lead to 
inbreeding depression (Allendorf and Luikart 2007, pp. 117-146). Small, 
isolated populations, therefore, are more susceptible to environmental 
pressures, including habitat degradation and stochastic events, and 
thus are the most susceptible to extinction (Primack 2008, pp. 151-
153). It is likely that some populations of the fluted kidneyshell and 
slabside pearlymussel are below the effective population size 
(Soul[eacute] 1980, pp. 162-264; Allendorf and Luikart 2007, pp. 147-
170) required to maintain long-term genetic and population viability.
    The present distribution and status of the fluted kidneyshell in 
the upper Cumberland River system in Kentucky may provide an excellent 
example of the detrimental bottleneck effect resulting when a minimum 
viable population size is not maintained. A once large population of 
this species occurred throughout the upper Cumberland River mainstem 
below Cumberland Falls and in several larger tributary systems. In this 
region, there were no absolute barriers to genetic interchange among 
its subpopulations (and those of its host fishes) that occurred in 
various streams. With the completion of Wolf Creek Dam in the late 
1960s, the mainstem population was soon extirpated, and the remaining 
populations isolated by the filling of Cumberland Reservoir. Whereas 
small, isolated, tributary populations of imperiled short-lived species 
(e.g., most fishes) would have died out within a decade or so after 
impoundment, the long-lived fluted kidneyshell would potentially take 
decades to expire post-impoundment. Without the level of genetic 
interchange the species experienced historically (i.e., without the 
reservoir barrier), isolated populations may be slowly dying out. The 
fluted kidneyshell and slabside pearlymussel were similarly isolated by 
the completion of multiple reservoirs in the Tennessee River system. 
Even given the improbable absence of anthropogenic impacts, we may lose 
smaller isolated populations of the fluted kidneyshell and slabside 
pearlymussel to the devastating consequences of below-threshold 
effective population size (the minimum population size that is needed 
for the population to reproduce and continue to be viable). In reality, 
degradation of these isolated stream reaches and the resulting decline 
in suitable habitat is contributing to the decline of both species.
Random Catastrophic Events
    The remaining populations of the fluted kidneyshell and slabside 
pearlymussel are generally small and geographically isolated. The 
patchy distribution pattern of populations in short river reaches makes 
them much more susceptible to extirpation from single catastrophic 
events, such as toxic chemical spills. Such a spill occurred in the 
upper Clinch River in 1998, killing many fluted kidneyshell and 
thousands of specimens of other mussel species, including three 
federally listed species (Henley et al. 2002, entire). High levels of 
isolation makes natural recolonization of any extirpated population 
impossible.
Climate Change
    Our analyses under the Act include consideration of ongoing and 
projected changes in climate. The terms ``climate'' and ``climate 
change'' are defined by the Intergovernmental Panel on Climate Change 
(IPCC). ``Climate'' refers to the mean (average) and variability of 
different types of weather conditions over time, with 30 years being a 
typical period for such measurements, although shorter or longer 
periods also may be used (IPCC 2007, p. 78). The term ``climate 
change'' thus refers to a change in the mean or variability of one or 
more measures of climate (e.g., temperature or precipitation) that 
persists for an extended period, typically decades or longer, whether 
the change is due to natural variability, human activity, or both (IPCC 
2007, p. 78). Various types of changes in climate can have direct or 
indirect effects on species. These effects may be positive, neutral, or 
negative and they may change over time, depending on the species and 
other relevant considerations, such as the effects of interactions of 
climate with other variables (e.g., habitat fragmentation) (IPCC 2007, 
pp. 8-14, 18-19). In our analyses, we use our expert judgment to weigh 
relevant information, including uncertainty, in our consideration of 
various aspects of climate change.
    There is a growing concern that climate change may lead to 
increased frequency of severe storms and droughts (McLaughlin et al. 
2002, p. 6074; Cook et al. 2004, p. 1015; Golladay et al. 2004, p. 
504). Specific effects of climate change to mussels, their habitat, and 
their fish hosts could include changes in stream temperature regimes, 
the timing and levels of precipitation causing more frequent and severe 
floods and droughts, and nonindigenous species introductions. Increases 
in temperature and reductions in flow may also lower dissolved oxygen 
levels in interstitial habitats which can be lethal to juveniles 
(Sparks and Strayer 1998, pp. 131-133). Effects to mussel populations 
from these environmental changes could include reduced abundance and 
biomass, altered species composition, and reduced host fish 
availability (Galbraith et al. 2010, pp. 1180-1182). The present 
conservation status, complex life

[[Page 60819]]

histories, and specific habitat requirements of mussels suggest that 
they may be quite sensitive to the effects of climate change (Hastie et 
al. 2003, p. 45).
    During high flows, flood scour can dislodge mussels where they may 
be injured, buried, swept into unsuitable habitats, or stranded and 
perish when flood waters recede (Vannote and Minshall 1982, p. 4105; 
Tucker 1996, p. 435; Hastie et al. 2001, pp. 107-115; Peterson et al. 
2011, unpaginated). During drought, stream channels may become 
disconnected pools where mussels are exposed to higher water 
temperatures, lower dissolved oxygen levels, and easier collection by 
predators, or channels may become dewatered entirely. Increased human 
demand and competition for surface and ground water resources for 
irrigation and consumption during drought can cause drastic reductions 
in stream flows and alterations to hydrology (Golladay et al. 2004, p. 
504; Golladay et al. 2007, unpaginated). Extended droughts occurred in 
the Southeast during 1998 to 2002, and again in 2006 to 2008. The 
effects of these recent droughts on these mussels are unknown; however, 
substantial declines in mussel diversity and abundance as a direct 
result of drought have been documented in southeastern streams 
(Golladay et al. 2004, pp. 494-503; Haag and Warren 2008, p. 1165).
Nonindigenous Species
    The Asian clam (Corbicula fluminea) has been introduced to the 
Cumberland and Tennessee River drainages and may be adversely affecting 
the fluted kidneyshell and slabside pearlymussel through direct 
competition for space and resources. The Asian clam may pose a direct 
threat to native mussels, particularly as juveniles, as a competitor 
for resources such as food, nutrients, and space (Neves and Widlak 
1987, p. 6). Dense populations of Asian clams may ingest large numbers 
of unionid sperm, glochidia, and newly metamorphosed juveniles, and may 
actively disturb sediments, reducing habitable space for juvenile 
native mussels or displacing them downstream (Strayer 1999, p. 82; 
Yeager et al. 2000, pp. 255-256).
    Asian clam densities vary widely in the absence of native mussels 
or in patches with sparse mussel concentrations, but Asian clam density 
is rarely observed to be high in dense mussel beds, indicating that the 
clam is unable to successfully invade small-scale habitat patches with 
high unionid biomass (Vaughn and Spooner 2006, pp. 334-335). The 
invading clam, therefore, appears to preferentially invade sites where 
mussels are already in decline (Strayer 1999, pp. 82-83; Vaughn and 
Spooner 2006, pp. 332-336) and does not appear to be a causative factor 
in the decline of mussels in dense beds. However, an Asian clam 
population that thrives in previously stressed, sparse mussel 
populations might exacerbate unionid imperilment through competition 
and impeding mussel population expansion (Vaughn and Spooner 2006, pp. 
335-336).
Summary for Factor E
    We have determined that other natural and manmade factors, such as 
alteration of natural temperature regimes; chemical contaminants; 
sedimentation; small, isolated populations; and low genetic diversity, 
combined with localized extinctions from point source pollution or 
accidental toxic chemical spills, habitat modification and progressive 
degradation by nonpoint source pollutants, natural catastrophic changes 
to habitat through flood scour or drought, and nonindigenous species 
are threats to remaining populations of the fluted kidneyshell and 
slabside pearlymussel across their respective ranges.

Proposed Determination

    We have carefully assessed the best scientific and commercial 
information available regarding the past, present, and future threats 
to the fluted kidneyshell and slabside pearlymussel. Section 3(6) of 
the Act defines an endangered species as ``any species which is in 
danger of extinction throughout all or a significant portion of its 
range,'' and section 3(20) of the Act defines a threatened species as 
``any species which is likely to become an endangered species within 
the foreseeable future throughout all or a significant portion of its 
range.'' As described in detail above, these two species occupy only 
portions of their historical ranges, are limited to a handful of viable 
populations, and are currently at risk throughout all of their 
respective ranges due to ongoing threats of habitat destruction and 
modification (Factor A), inadequacy of existing regulatory mechanisms 
(Factor D), and other natural or manmade factors affecting their 
continued existence (Factor E). Specifically, these threats include 
impoundments, mining, oil and gas exploration, sedimentation, chemical 
contaminants, temperature regime alterations, recurring drought and 
flooding, population fragmentation and isolation, loss of fish hosts, 
and the introduced Asian clam. We believe these threats are currently 
impacting these species and are projected to continue and potentially 
worsen in the future.
    Species with small ranges, few populations, and small or declining 
population sizes are the most vulnerable to extinction (Primack 2008, 
p. 137). The effects of certain factors, particularly habitat 
degradation and loss, catastrophic events, and introduced species, 
increase in magnitude when population size is small (Soul[eacute] 1987, 
pp. 33, 71; Primack 2008, pp. 133-135, 152). We believe that, when 
combining the effects of historical, current, and future habitat loss 
and degradation; historical and ongoing drought; and the exacerbating 
effects of small and declining population sizes and curtailed ranges, 
the fluted kidneyshell and slabside pearlymussel are in danger of 
extinction throughout all of their ranges. In addition, any factor 
(i.e., habitat loss or natural and manmade factors) that results in a 
further decline in habitat or individuals may be problematic for the 
long-term recovery of these species.
    Therefore, based on the best available scientific and commercial 
information, we propose to list the fluted kidneyshell and slabside 
pearlymussel as endangered species throughout all of their ranges. We 
believe that, when combining the effects of historical, current, and 
future habitat loss and degradation; historical and ongoing drought; 
and the exacerbating effects of small and declining population sizes 
and curtailed ranges, the fluted kidneyshell and slabside pearlymussel 
are in danger of extinction throughout all of their ranges. 
Furthermore, we examined both species to analyze if any significant 
portions of their ranges may warrant a different status. However, 
because of their limited and curtailed ranges, and uniformity of the 
threats throughout their entire respective ranges, we find there are no 
significant portions of any of the species' ranges that may warrant a 
different determination of status.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened under the Act include recognition, recovery actions, 
requirements for Federal protection, and prohibitions against certain 
practices. Recognition through listing results in public awareness and 
conservation by Federal, State, and local agencies; private 
organizations; and individuals. The Act encourages cooperation with the 
States and requires that recovery actions be carried out for all listed

[[Page 60820]]

species. The protection measures required of Federal agencies and the 
prohibitions against certain activities involving listed wildlife are 
discussed in Effects of Critical Habitat Designation and are further 
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. Subsection 4(f) of the Act requires the Service to develop and 
implement recovery plans for the conservation of endangered and 
threatened species. The recovery planning process involves the 
identification of actions that are necessary to halt or reverse the 
species' decline by addressing the threats to its survival and 
recovery. 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.
    Recovery planning includes the development of a recovery outline 
shortly after a species is listed, preparation of a draft and final 
recovery plan, and revisions to the plan as significant new information 
becomes available. The recovery outline guides the immediate 
implementation of urgent recovery actions and describes the process to 
be used to develop a recovery plan. The recovery plan identifies site-
specific management actions that will achieve recovery of the species, 
measurable criteria that determine when a species may be downlisted or 
delisted, 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. Recovery teams (comprised of species experts, Federal and State 
agencies, nongovernment organizations, and stakeholders) are often 
established to develop recovery plans. When completed, the recovery 
outline, draft recovery plan, and the final recovery plan will be 
available on our Web site (https://www.fws.gov/endangered), or from our 
Tennessee Ecological Services Field Office (see FOR FURTHER INFORMATION 
CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribal, nongovernmental organizations, businesses, 
and private landowners. Examples of recovery actions include habitat 
restoration (e.g., restoration of native vegetation), research, captive 
propagation and reintroduction, and outreach and education. The 
recovery of many listed species cannot be accomplished solely on 
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires 
cooperative conservation efforts on private, State, and Tribal lands.
    If this species is listed, funding for recovery actions 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, 
under section 6 of the Act, States would be eligible for Federal funds 
to implement management actions that promote the protection and 
recovery of these two species. Information on our grant programs that 
are available to aid species recovery can be found at: https://www.fws.gov/grants.
    Although the fluted kidneyshell and slabside pearlymussel 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 this 
species. Additionally, we invite you to submit any new information on 
this species whenever it becomes available and any information you may 
have for recovery planning purposes (see FOR FURTHER INFORMATION 
CONTACT).
    Section 7(a) of the Act requires Federal agencies to evaluate their 
actions with respect to any species that is proposed or listed as 
endangered or threatened 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)(4) of the Act requires Federal agencies to confer with the 
Service on any action that is likely to jeopardize the continued 
existence of a species proposed for listing or result in destruction or 
adverse modification of proposed critical habitat. If a species is 
listed subsequently, section 7(a)(2) of the Act requires Federal 
agencies to ensure that activities they authorize, fund, or carry out 
are not likely to jeopardize the continued existence of the species or 
destroy or adversely modify its critical habitat. If a Federal action 
may affect a listed species or its critical habitat, the responsible 
Federal agency must enter into formal consultation with the Service.
    Federal agency actions within the species habitat that may require 
conference or consultation or both as described in the preceding 
paragraph include management of and any other landscape altering 
activities on Federal lands administered by the U.S. Forest Service; 
issuance of section 404 CWA permits by the U.S. Army Corps of 
Engineers; licensing of hydroelectric dams, and construction and 
management of gas pipeline and power line rights-of-way approved by the 
Federal Energy Regulatory Commission; issuance of 26a permits by the 
Tennessee Valley Authority; construction and maintenance of roads or 
highways funded by the Federal Highway Administration; and land 
management practices administered by the U.S. Department of 
Agriculture. It has been the experience of the Service from 
consultations on other species, however, that nearly all section 7 
consultations have been resolved so that the species have been 
protected and the project objectives have been met.
    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply to all endangered 
wildlife. The prohibitions, codified at 50 CFR 17.21 for endangered 
wildlife, make it illegal for any person subject to the jurisdiction of 
the United States to take (includes harass, harm, pursue, hunt, shoot, 
wound, kill, trap, capture, or collect; or to attempt any of these), 
import, export, ship in interstate commerce in the course of commercial 
activity, or sell or offer for sale in interstate or foreign commerce 
any listed species. Under the Lacey Act (18 U.S.C. 42-43; 16 U.S.C. 
3371-3378), it is also illegal to possess, sell, deliver, carry, 
transport, or ship any such wildlife that has been taken illegally. 
Certain exceptions apply to agents of the Service and State 
conservation agencies.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered and threatened wildlife species under certain 
circumstances. Regulations governing permits are codified at 50 CFR 
17.22 for endangered species, and at 17.32 for threatened species. With 
regard to endangered wildlife, a permit must 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.
    It is our policy, as published in the Federal Register on July 1, 
1994 (59 FR 34272), to identify, to the maximum extent practicable at 
the time a species is listed, those activities that would or would not 
constitute a violation of section 9 of the Act. The intent of this 
policy is to increase public awareness of the effect of a proposed 
listing on proposed and ongoing activities within the range of species 
proposed for listing. The following activities could potentially result 
in a violation of

[[Page 60821]]

section 9 of the Act; this list is not comprehensive:
    (1) Unauthorized collecting, handling, possessing, selling, 
delivering, carrying, or transporting of the species, including import 
or export across State lines and international boundaries, except for 
properly documented antique specimens of these taxa at least 100 years 
old, as defined by section 10(h)(1) of the Act.
    (2) Introduction of nonnative species that compete with or prey 
upon these mussel species, such as the zebra mussel (Dreissena 
polymorpha) and Asian clam (Corbicula fluminea).
    (3) Unauthorized modification of the channel, substrate, 
temperature, or water flow of any stream or water body in which these 
species are known to occur.
    (4) Unauthorized discharge of chemicals or fill material into any 
waters in which the fluted kidneyshell and slabside pearlymussel are 
known to occur.
    Questions regarding whether specific activities would constitute a 
violation of section 9 of the Act should be directed to the Tennessee 
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT). 
Requests for copies of the regulations concerning listed animals and 
general inquiries regarding prohibitions and permits may be addressed 
to the U.S. Fish and Wildlife Service, Endangered Species Permits, 1875 
Century Boulevard, Suite 200, Atlanta, GA 30345; telephone: 404-679-
7140; facsimile: 404-679-7081.

Critical Habitat for the Fluted Kidneyshell and Slabside Pearlymussel

Background

    It is our intent to discuss below only those topics directly 
relevant to the designation of critical habitat for the fluted 
kidneyshell and slabside pearlymussel in this section of the proposed 
rule.
    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.
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
an endangered or threatened species to the point at which the measures 
provided pursuant to the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management such as research, census, law 
enforcement, habitat acquisition and maintenance, propagation, live 
trapping, and transplantation, and, in the extraordinary case where 
population pressures within a given ecosystem cannot be otherwise 
relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that Federal agencies ensure, in consultation 
with the Service, that any action they authorize, fund, or carry out is 
not likely to result in the destruction or adverse modification of 
critical habitat. The designation of critical habitat does not affect 
land ownership or establish a refuge, wilderness, reserve, preserve, or 
other conservation area. Such designation does not allow the government 
or public to access private lands. Such designation does not require 
implementation of restoration, recovery, or enhancement measures by 
non-Federal landowners. Where a landowner seeks or requests Federal 
agency funding or authorization for an action that may affect a listed 
species or critical habitat, the consultation requirements of section 
7(a)(2) would apply, but even in the event of a destruction or adverse 
modification finding, the obligation of the Federal action agency and 
the landowner is not to restore or recover the species, but to 
implement reasonable and prudent alternatives to avoid destruction or 
adverse modification of critical habitat.
    Under the first prong of the Act's definition of critical habitat, 
areas within the geographical area occupied by the species at the time 
it is listed must contain physical or biological features (PBFs) which 
are (1) essential to the conservation of the species and (2) which may 
require special management considerations or protection. For these 
areas, critical habitat designations identify, to the extent known 
using the best scientific and commercial data available, those PBFs 
that are essential to the conservation of the species (such as space, 
food, cover, and protected habitat). In identifying those physical and 
biological features within an area, we focus on the principal 
biological or physical constituent elements (primary constituent 
elements such as roost sites, nesting grounds, seasonal wetlands, water 
quality, tide, soil type) that are essential to the conservation of the 
species. Primary constituent elements are the specific elements of PBFs 
that provide for a species' life-history processes.
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in areas outside the geographical 
area occupied by the species at the time it is listed, upon a 
determination that such areas are essential for the conservation of the 
species. We designate critical habitat in areas outside the 
geographical area occupied by a species only when a designation limited 
to its range would be inadequate to ensure the conservation of the 
species.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific and commercial data available. 
Further, our Policy on Information Standards under the Endangered 
Species Act (published in the Federal Register on July 1, 1994 (59 FR 
34271)), the Information Quality Act (section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658)), and our associated Information Quality 
Guidelines, provide criteria, establish procedures, and provide 
guidance to ensure that our decisions are based on the best scientific 
data available. They require our biologists, to the extent consistent 
with the Act and with the use of the best scientific data available, to 
use primary and original sources of information as the basis for 
recommendations to designate critical habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information developed during the listing process for the species. 
Additional information sources may include articles in peer-reviewed 
journals, conservation plans developed by States and counties, 
scientific status surveys and studies, biological assessments, or other 
unpublished materials and expert opinion or personal knowledge.
    Habitat is dynamic, and species may move from one area to another 
over time. Climate change will be a particular challenge for 
biodiversity because the interaction of additional stressors associated 
with climate change and current stressors may push species beyond their 
ability to survive (Lovejoy 2005, pp. 325-326).
    We recognize that critical habitat designated at a particular point 
in time may not include all of the habitat areas

[[Page 60822]]

that we may later determine are necessary for the recovery of the 
species. For these reasons, a critical habitat designation does not 
signal that habitat outside the designated area is unimportant or may 
not be needed for recovery of the species. Areas that are important to 
the conservation of the species, both inside and outside the critical 
habitat designation, will continue to be subject to: (1) Conservation 
actions implemented under section 7(a)(1) of the Act, (2) regulatory 
protections afforded by the requirement in section 7(a)(2) of the Act 
for Federal agencies to insure their actions are not likely to 
jeopardize the continued existence of any endangered or threatened 
species, and (3) the prohibitions of section 9 of the Act if actions 
occurring in these areas may affect the species. Federally funded or 
permitted projects affecting listed species outside their designated 
critical habitat areas may still result in jeopardy findings in some 
cases. These protections and conservation tools would continue to 
contribute to recovery of these species. Similarly, critical habitat 
designations made on the basis of the best available information at the 
time of designation would not control the direction and substance of 
future recovery plans, habitat conservation plans (HCPs), or other 
species conservation planning efforts if new information available at 
the time of these planning efforts calls for a different outcome.

Prudency Determination

    Section 4(a)(3) of the Act, as amended, and implementing 
regulations (50 CFR 424.12), require that, to the maximum extent 
prudent and determinable, the Secretary designate critical habitat at 
the time the species is determined to be an endangered or threatened 
species. Our regulations (50 CFR 424.12(a)(1)) state that the 
designation of critical habitat is not prudent when one or both of the 
following situations exist: (1) The species is threatened by taking or 
other human activity, and identification of critical habitat can be 
expected to increase the degree of threat to the species, or (2) such 
designation of critical habitat would not be beneficial to the species.
    As discussed above under Factor B, there is currently no imminent 
threat of take attributed to collection or vandalism for these species, 
and identification and mapping of critical habitat is not expected to 
initiate any such threat. In the absence of finding that the 
designation of critical habitat would increase threats to a species, if 
there are any benefits to a critical habitat designation, then a 
prudent finding is warranted. The potential benefits of designation 
include: (1) Triggering consultation under section 7 of the Act, in new 
areas for actions in which there may be a Federal nexus where it would 
not otherwise occur because, for example, it is or has become 
unoccupied or the occupancy is in question; (2) focusing conservation 
activities on the most essential features and areas; (3) providing 
educational benefits to State or county governments or private 
entities; and (4) preventing people from causing inadvertent harm to 
the species. Therefore, because we have determined that the designation 
of critical habitat will not likely increase the degree of threat to 
the species and may provide some measure of benefit, we find that 
designation of critical habitat is prudent for the fluted kidneyshell 
and slabside pearlymussel.

Critical Habitat Determinability

    Having determined that designation is prudent, under section 
4(a)(3) of the Act we must find whether critical habitat for the two 
species is determinable. Our regulations at 50 CFR 424.12(a)(2) state 
that critical habitat is not determinable when one or both of the 
following situations exist:
    (i) Information sufficient to perform required analyses of the 
impacts of the designation is lacking, or
    (ii) The biological needs of the species are not sufficiently well 
known to permit identification of an area as critical habitat.
    When critical habitat is not determinable, the Act allows the 
Service an additional year to publish a critical habitat designation 
(16 U.S.C. 1533(b)(6)(C)(ii)).
    We reviewed the available information pertaining to the biological 
needs of the species and habitat characteristics where these species 
are located. This and other information represent the best scientific 
data available and led us to conclude that critical habitat is 
determinable for these two species.

Physical and Biological Features

    In accordance with sections 3(5)(A)(i) and 4(b)(1)(A) of the Act 
and the regulations at 50 CFR 424.12, in determining which areas within 
the geographical area occupied at the time of listing to propose as 
critical habitat, we consider the PBFs essential to the conservation of 
the species which may require special management considerations or 
protection. These include, but are not limited to:
    (1) Space for individual and population growth and for normal 
behavior;
    (2) Food, water, air, light, minerals, or other nutritional or 
physiological requirements;
    (3) Cover or shelter;
    (4) Sites for breeding, reproduction, or rearing (or development) 
of offspring; and
    (5) Habitats that are protected from disturbance or are 
representative of the historic, geographical, and ecological 
distributions of a species.
    We derive the specific PBFs required for the fluted kidneyshell and 
slabside pearlymussel based on their biological needs. Little is known 
of the specific habitat requirements of these two mussel species other 
than they require flowing water, stable stream channels, adequate water 
quality, and fish hosts for development of larva to metamorphose into 
juvenile mussels. To identify the physical and biological needs of the 
species, we have relied on current conditions at locations where the 
species survive, the limited information available on these two mussels 
and their close relatives, and factors associated with the decline and 
extirpation of these and other mussels from portions of the Cumberland 
and Tennessee River systems. Additional information can be found in the 
Background section of this proposed rule. We have determined that the 
following PBFs are essential for the fluted kidneyshell and slabside 
pearlymussel.

Space for Individual and Population Growth and for Normal Behavior

    The fluted kidneyshell and slabside pearlymussel are historically 
associated with the Cumberland and Tennessee River drainages in 
Alabama, Kentucky, Mississippi, Tennessee, and Virginia. Mussels 
generally live embedded in the bottom of stable streams and other 
bodies of water, and within riffle areas of sufficient current 
velocities to remove finer sediments and provide well-oxygenated 
waters. The fluted kidneyshell is primarily a medium-sized creek to 
large river species, inhabiting sand and gravel substrates in 
relatively shallow riffles and shoals with moderate to swift current 
(Parmalee and Bogan 1998, p. 205). In comparison to co-occurring 
species, the fluted kidneyshell demonstrates strong habitat 
specificity. It is associated with faster flows, greater baseflow shear 
stress, and low substrate embeddedness (Ostby 2005, pp. 51, 142-143). 
The slabside pearlymussel is primarily a large creek to large river 
species, inhabiting sand, fine gravel, and cobble substrates in 
relatively

[[Page 60823]]

shallow riffles and shoals with moderate current (Parmalee and Bogan 
1998, p. 152).
    Fluted kidneyshell and slabside pearlymussel, similar to other 
mussels, are dependent on areas with flow refuges where shear stress is 
relatively low, although the fluted kidneyshell is more tolerant of 
shear stress than other species, and sediments remain stable during 
flood events (Layzer and Madison 1995, p. 341; Strayer 1999, pp. 468 
and 472; Hastie et al. 2001, pp. 111-114). Flow refuges conceivably 
allow relatively immobile mussels such as the fluted kidneyshell and 
slabside pearlymussel to remain in the same general location throughout 
their entire lives.
    Natural river or creek channel stability are achieved by allowing 
the river or creek to develop a stable dimension, pattern, and profile 
such that, over time, channel features are maintained and the river or 
creek system neither aggrades nor degrades. Channel instability occurs 
when the scouring process leads to degradation, or excessive sediment 
deposition results in aggradation. Stable rivers and creeks 
consistently transport their sediment load, both in size and type, 
associated with local deposition and scour (Rosgen 1996, p. 1-3). 
Sedimentation has been determined to be a major factor in habitat 
destruction, resulting in corresponding shift in mussel fauna (Brim Box 
and Mossa 1999, p. 102). Stable stream bottom substrates not only 
provide space for populations of these mussel species, but also provide 
cover and shelter and sites for breeding, reproduction, and growth of 
offspring.
    Habitat conditions described in the previous paragraphs provide 
space, cover, shelter, and sites for breeding, reproduction, and growth 
of offspring for the fluted kidneyshell and slabside pearlymussel. 
These habitats are dynamic and are formed and maintained by water 
quantity, channel features (dimension, pattern, and profile), and 
sediment input to the system through periodic flooding, which maintains 
connectivity and interaction with the flood plain. Changes in one or 
more of these parameters can result in channel degradation or 
aggradation, with serious effects to mussels.
    Therefore, based on the information above, we identify riffles of 
large creeks and rivers with sand, gravel, and cobble substrates; areas 
of moderate to high amount of flow, but with refugia of low shear 
stress; stream channel stability; and floodplain connectivity to be 
PBFs for both of these species.

Food, Water, Air, Light, Minerals, or Other Nutritional or 
Physiological Requirements

    Mussels, such as these two species, siphon water into their shells 
and across four gills that are specialized for respiration, food 
collection, and brooding larvae in females. Food items include detritus 
(disintegrated organic debris), algae, diatoms, and bacteria (Strayer 
et al. 2004, pp. 430-431). Encysted glochidia are nourished by their 
fish hosts and feed for a period of one week to several months. 
Nutrient uptake by glochidia is not well understood, but probably 
occurs through the microvillae of the mantle (Watters 2007, p. 55). For 
the first several months, juvenile mussels partially employ pedal 
(foot) feeding, extracting bacteria, algae, and detritus from the 
sediment, although they also may filter interstitial (pore) water 
(Yeager et al. 1994, pp. 217-221). However, their gills are rudimentary 
and generally incapable of filtering particles (Watters 2007, p. 56). 
Adult mussels also can obtain their food by deposit feeding, pulling in 
food from the sediment and its interstitial (pore) water and pedal 
feeding directly from the sediment (Yeager et al. 1994, pp. 217-221; 
Vaughn and Hakenkamp 2001, pp. 1432-1438). Food availability and 
quality for the fluted kidneyshell and slabside pearlymussel in their 
habitats are affected by habitat stability, floodplain connectivity, 
flow, and water and sediment quality. Excessive sedimentation has been 
shown to impair the filter feeding ability of mussels. When in high 
silt environments, mussels may keep their valves closed more often, 
resulting in reduced feeding activity (Ellis 1936, p. 30), and high 
amounts of suspended sediments can dilute their food source (Dennis 
1984, p. 212). Adequate food availability and quality is essential for 
normal behavior, growth, and viability during all life stages of these 
two species. Excessive sedimentation often results in fine silt 
particles culminating within interstitial spaces, embedding and even 
concretizing the substrate and virtually altering habitat to such a 
degree that it becomes uninhabitable for mussels, particularly 
juveniles.
    The fluted kidneyshell and slabside pearlymussel are riverine 
species that depend upon adequate water flow. Continuously flowing 
water is a habitat feature associated with both of these species. 
Flowing water maintains the stream bottom habitats where these species 
are found, transports food items to the sedentary juvenile and adult 
life stages, removes wastes, and provides oxygen for respiration. A 
natural flow regime that includes periodic flooding and maintains 
connectivity and interaction with the floodplain is critical for the 
exchange of nutrients, movement of and spawning activities for 
potential fish hosts, and maintenance of flow refuges in riffle and run 
habitats. Further, riffle areas are often defined by an abundance and 
diversity of organisms that likely have dependent and competitive 
interactions yet unknown, but that are important for riffle-dwelling 
mussel species such as the fluted kidneyshell and slabside 
pearlymussel.
    The ranges of standard physical and chemical water quality 
parameters (such as temperature, dissolved oxygen, pH, and 
conductivity) that define suitable habitat conditions for the two 
species have not been investigated or are poorly understood. However, 
as relatively sedentary animals, mussels must tolerate the full range 
of such parameters that occur naturally within the streams where they 
persist. The pathways of exposure to a variety of environmental 
pollutants for all four mussel life stages (free and encysted 
glochidia, juveniles, and adults) and differences in exposure and 
sensitivity were previously discussed (see Factor A). Environmental 
contamination is a causal (contributing) factor in the decline of 
mussel populations.
    We currently believe that most numeric standards for pollutants and 
water quality parameters (for example, dissolved oxygen, pH, and heavy 
metals) that have been adopted by the States under the CWA represent 
levels that are essential to the conservation of both mussels. The 
Service is currently in consultation with the EPA to evaluate the 
protectiveness of criteria approved in EPA's water quality standards 
for endangered and threatened species and their critical habitats as 
described in the Memorandum of Agreement that our agencies signed in 
2001 (66 FR 11201, February 22, 2001). Other factors that can 
potentially alter water quality are droughts and periods of low flow, 
nonpoint source runoff from adjacent land surfaces (for example, 
excessive amounts of sediments, nutrients, and pesticides), point 
source discharges from municipal and industrial wastewater treatment 
facilities (for example, excessive amounts of ammonia, chlorine, and 
metals), thermal and flow modifications resulting from hydropower 
generation, and random spills or unregulated discharge events. This 
could be particularly harmful during drought conditions, when flows are 
depressed and pollutants are more concentrated.

[[Page 60824]]

    Both the amount (flow) and the physical and chemical conditions 
(water quality) where both species currently exist vary widely 
according to season, precipitation events, and seasonal human 
activities within the watershed. Conditions across their historical 
ranges vary even more due to watershed size, geology, geography, and 
differences in human population densities and land uses. In general, 
both of the species survive in areas where the magnitude, frequency, 
duration, and seasonality of water flow are adequate to maintain stable 
habitats (for example, sufficient flow to remove fine particles and 
sediments without causing degradation), and where water quality is 
adequate for year-round survival (for example, moderate to high levels 
of dissolved oxygen, low to moderate input of nutrients, and relatively 
unpolluted water and sediments). Therefore, based on the information 
above, we identify adequate food items for all life stages, sufficient 
water flow, and adequate water quality to be PBFs for both of these 
species.

Sites for Breeding, Reproduction, or Rearing

    Mussels require a host fish for transformation of larval mussels 
(glochidia) to juvenile mussels (Williams et al. 2008, p. 68). Thus, 
the presence of the appropriate host fishes to complete the 
reproductive life cycle is essential to the conservation of these two 
mussels. The known host fishes of the fluted kidneyshell include: 
barcheek darter (Etheostoma obeyense), fantail darter (E. flabellare), 
rainbow darter (E. caeruleum), redline darter (E. rufilineatum), 
bluebreast darter (E. camurum), dusky darter (Percina sciera), and 
banded sculpin (Cottus carolinae). The known host fishes of the 
slabside pearlymussel include: popeye shiner (Notropis ariommus), 
rosyface shiner (N. rubellus), saffron shiner (N. rubricroceus), silver 
shiner (N. photogenis), telescope shiner (N. telescopus), Tennessee 
shiner (N. leuciodus), whitetail shiner (Cyprinella galactura), striped 
shiner (Luxilus chrysocephalus), warpaint shiner (L. coccogenis), white 
shiner (L. albeolus), and eastern blacknose dace (Rhinichthys 
atratulus). There are likely other suitable host fishes that have not 
yet been studied or confirmed.
    Juvenile mussels require stable bottom habitats for growth and 
survival. Fluted kidneyshell and slabside pearlymussel juveniles 
require stable habitats with adequate water quantity and quality as 
previously described for growth and survival. Excessive sediments or 
dense growth of filamentous algae can expose juvenile mussels to 
entrainment or predation and be detrimental to the survival of juvenile 
mussels (Hartfield and Hartfield 1996, pp. 372-374). Geomorphic 
instability can result in the loss of interstitial habitats and 
juvenile mussels due to scouring or deposition (Hartfield 1993, pp. 
372-373). Water quality, sediment quality, stable habitat, health of 
fish hosts, and diet (of all life stages) all influence survival of 
each life stage and subsequent reproduction and recruitment (Cope et 
al. 2008, p. 452).
    Periodic floodplain connectivity that occurs during wet years 
provides habitats for spawning and foraging activities for fish hosts 
that require floodplain habitats for successful reproduction and 
recruitment to adulthood. Barko et al. (2006, pp. 252-256) found that 
several fish host or potential host species (none of which are 
documented hosts for the fluted kidneyshell or slabside pearlymussel) 
benefited from resource exploitation of floodplain habitats that were 
not typically available for use during years of normal flows. 
Furthermore, Kwak (1988, pp. 243-247) and Slipke and Maceina (2005, p. 
289) indicated that periodic inundation of floodplain habitats 
increased successful fish reproduction, which leads to increased 
availability of native host fishes for mussel reproduction. However, 
Rypel et al. (2009, p. 502) indicated that mussels tended to exhibit 
minimal growth during high flow years. Therefore, optimal flooding of 
these habitats would not be too frequent and may need to occur at 
similar frequencies to that of the natural hydrologic regime of the 
rivers and creeks inhabited by the fluted kidneyshell and slabside 
pearlymussel.
    Natural temperature regimes can be altered by impoundments, water 
releases from dams, industrial and municipal effluents, and changes in 
riparian habitat. Critical thermal limits for survival and normal 
functioning of many mussel species are unknown. High temperatures can 
reduce dissolved oxygen concentrations in the water, which slows 
growth, reduces glycogen stores, impairs respiration, and may inhibit 
reproduction (Hart and Fuller 1974, pp. 240-241). Low temperatures can 
significantly delay or prevent metamorphosis (Watters and O'Dee 1999, 
pp. 454-455). Water temperature increases have been documented to 
shorten the period of glochidial encystment, reduce the speed in which 
they turn upright, increase oxygen consumption, and slow burrowing and 
movement responses (Hart and Fuller 1974, pp. 240-241; Bartsch et al. 
2000, p. 237; Watters et al. 2001, p. 546; Schwalb and Pusch 2007, pp. 
264-265). Several studies have documented the influence of temperature 
on the timing of aspects of mussel reproduction (for example, Gray et 
al. 2002, p. 156; Allen et al. 2007, p. 85; Steingraeber et al. 2007, 
pp. 303-309). Peak glochidial releases are associated with water 
temperature thresholds that can be thermal minimums or maximums, 
depending on the species (Watters and O'Dee 2000, p. 136). Abnormal 
temperature changes may cause particular problems to mussels whose 
reproductive cycles may be linked to fish reproductive cycles (for 
example, Young and Williams 1984, entire). Therefore, based on the 
information above, we identify health of fish hosts, water quality, 
sediment quality, stable habitat, food for all life stages, periodic 
flooding of floodplain habitat, and a natural temperature regime to be 
PBFs for both of these species.

Primary Constituent Elements for the Fluted Kidneyshell and Slabside 
Pearlymussel

    Under the Act and its implementing regulations, we are required to 
identify the PBFs essential to the conservation of these mussel species 
in areas occupied at the time of listing, focusing on the features' 
primary constituent elements (PCEs). We consider PCEs to be the 
elements of PBFs that provide for a species' life-history processes and 
are essential to the conservation of the species.
    Based on the above needs and our current knowledge of the life 
history, biology, and ecology of the species and the habitat 
requirements for sustaining the essential life-history functions of the 
species, we have determined that the PCEs for the fluted kidneyshell 
and slabside pearlymussel are:
    (1) Riffle habitats within large, geomorphically stable stream 
channels (channels that maintain lateral dimensions, longitudinal 
profiles, and sinuosity patterns over time without an aggrading or 
degrading bed elevation).
    (2) Stable substrates of sand, gravel, and cobble with low to 
moderate amounts of fine sediment and containing flow refugia with low 
shear stress.
    (3) A natural hydrologic flow regime (the magnitude, frequency, 
duration, and seasonality of discharge over time) necessary to maintain 
benthic habitats where the species are found, and connectivity of 
rivers with the floodplain, allowing the exchange of nutrients and 
sediment for habitat maintenance, food availability for all life 
stages, and spawning habitat for native fishes.

[[Page 60825]]

    (4) Water quality with low levels of pollutants and including a 
natural temperature regime, pH (between 6.0 to 8.5), oxygen content 
(not less than 5.0 milligrams per liter (mg/L)), hardness, and 
turbidity necessary for normal behavior, growth, and viability of all 
life stages.
    (5) The presence of abundant fish hosts necessary for recruitment 
of the fluted kidneyshell and slabside pearlymussel.

Special Management Considerations or Protection

    When designating critical habitat, we assess whether the specific 
areas within the geographical area occupied by the species at the time 
of listing contain features which are essential to the conservation of 
the species and which may require special management considerations or 
protection. The 29 occupied units we are proposing for designation as 
critical habitat for the fluted kidneyshell (16) and slabside 
pearlymussel (13) will require some level of management to address the 
current and future threats to the PBFs of the species. Of the 29 total 
occupied units, a portion of 5 units are located on the Daniel Boone 
National Forest (DBNF), 14 are almost entirely on private land, 1 is 
located on the Big South Fork National River and Recreational Area 
(BSFNRRA), 1 is located on the Cherokee National Forest (CNF), and 8 
units have mixed ownership with private, State park, and national 
wildlife refuge lands.
    Due to their location on the DBNF, at least a portion of 5 of the 
29 occupied proposed critical habitat units are being managed and 
protected under DBNF's Land and Resource Management Plan (LRMP), and 
the Hiwassee River unit is protected under CNF's LRMP (United States 
Forest Service (USFS) 2004a, pp. 1-14; 2004b, entire). The LRMPs are 
implemented through a series of project-level decisions based on 
appropriate site-specific analysis and disclosure. The LRMPs do not 
contain a commitment to select any specific project; rather, they set 
up a framework of desired future conditions with goals, objectives, and 
standards to guide project proposals. Projects are proposed to solve 
resource management problems, move the forest environment toward 
desired future conditions, and supply goods and services to the public 
(USFS 2004a, pp. 1-14). The LRMPs contain a number of protective 
standards that in general are designed to avoid and minimize potential 
adverse effects to the fluted kidneyshell, slabside pearlymussel, and 
federally listed species; however, the DBNF and CNF would continue to 
conduct project-specific section 7 consultations under the Act when 
their activities may adversely affect the fluted kidneyshell, slabside 
pearlymussel, and other federally listed species or adversely modify 
their designated critical habitats.
    Fourteen of the 29 occupied proposed critical habitat units are 
located almost entirely on private property and are not presently under 
the special management or protection provided by a legally operative 
plan or agreement for the conservation of the species.
    One of the 29 occupied proposed critical habitat units (Big South 
Fork Cumberland River) is located almost entirely on Federal lands 
within the BSFNRRA. Land and resource management decisions and 
activities within the BSFNRRA are guided by the National Park Service 
General Management Plan, Field Management Plan, and Draft Non-Federal 
Oil and Gas Management Plan (NPS 2005, entire; NPS 2006, pp. 1-12; NPS 
2011, entire).
    Eight of the 29 occupied proposed critical habitat units (Clinch 
and Duck Rivers) have mixed ownership with private, State park, and 
national wildlife refuge lands. These lands are operated under various 
plans that may or may not provide the special management or protection 
provided by a legally operative plan or agreement for the conservation 
of these species.
    Various activities in or adjacent to each of the occupied critical 
habitat units described in this proposed rule may affect one or more of 
the PCEs. Some of these activities include, but are not limited to, 
those discussed in the Summary of Factors Affecting the Species, above 
(e.g., impoundments, gravel and coal mining, water pollution, invasive 
species; see Factors A, D, and E, above). Other activities that may 
affect PBFs in the proposed critical habitat units include those listed 
in Available Conservation Measures above.
    Management activities that could ameliorate threats on both Federal 
and non-Federal lands include, but are not limited to: Use of BMPs 
designed to reduce sedimentation, erosion, and stream bank alteration; 
moderation of surface and ground water withdrawals to maintain natural 
flow regimes; increase of stormwater management and reduction of 
stormwater flows into the systems; preservation of headwater streams; 
regulation of off-road vehicle use; and reduction of other watershed 
and floodplain disturbances that release sediments, pollutants, or 
nutrients into the water.
    In summary, we find that the areas we are proposing as occupied 
critical habitat for the fluted kidneyshell and slabside pearlymussel 
contain the PBFs necessary for the species, and that these features may 
require special management considerations or protection. Special 
management consideration or protection may be required to eliminate, or 
to reduce to negligible levels, the threats affecting the PBFs of each 
unit. Additional discussion of threats facing individual units is 
provided in the individual unit descriptions below.

Criteria Used To Identify Critical Habitat

    As required by section 4(b) of the Act, we use the best scientific 
and commercial data to designate critical habitat. We review available 
information pertaining to the habitat requirements of the species. In 
accordance with the Act and its implementing regulation at 50 CFR 
424.12(e), we consider whether designating additional areas--outside 
those currently occupied as well as those occupied at the time of 
listing (if listing occurs before designation of a species' critical 
habitat)--are necessary to ensure the conservation of the species. We 
are proposing to designate critical habitat in areas within the 
geographic area currently occupied by the species. We also are 
proposing to designate specific areas outside the geographic area 
currently occupied by the species, which were historically occupied but 
are presently unoccupied, because such areas are essential for the 
conservation of the species.
    We began our analysis by considering historical and current ranges 
of both species. We used various sources including published literature 
and museum collection databases, as well as surveys, reports, and field 
notes prepared by biologists (see Background section). We then 
identified the specific areas that are occupied by both mussels and 
that contain one or more of the PBFs. We defined occupied habitat as 
those stream reaches known to be currently occupied by either of the 
two species. To identify the currently occupied stream reaches, we used 
post-1980 survey data. To identify the unoccupied stream reaches, we 
used survey data between the late 1800s and 1979. Therefore, if a 
species was known to occur in an area prior to 1980, but was not 
collected since then, the stream reach is considered unoccupied. This 
criterion was chosen because a large number of collections were 
conducted in the 1980s in the Cumberland and Tennessee River systems. 
Some of the historical occurrences have not been surveyed since the 
1980s. However, because of the longevity of these species

[[Page 60826]]

(40-55 years), they are still thought to occur in these areas.
    We then evaluated occupied stream reaches to delineate the probable 
upstream and downstream extent of each species' distribution. Known 
occurrences for some mussel species are extremely localized, and rare 
mussels can be difficult to locate. In addition, stream habitats are 
highly dependent upon upstream and downstream channel habitat 
conditions for their maintenance. Therefore, where more than one 
occurrence record of a particular species was found within a stream 
reach, we considered the entire reach between the uppermost and 
lowermost locations as occupied habitat.
    We then considered whether this essential area was adequate for the 
conservation of both species. Small, isolated, aquatic populations are 
subject to chance catastrophic events and to changes in human 
activities and land use practices that may result in their elimination. 
Larger, more contiguous populations can reduce the threat of extinction 
due to habitat fragmentation and isolation. For these reasons, we 
believe that conservation of the fluted kidneyshell, but not the 
slabside pearlymussel, requires expanding its range into currently 
unoccupied portions of its historical habitat. Given that threats to 
the fluted kidneyshell are compounded by its limited distribution and 
isolation, it is unlikely that currently occupied habitat is adequate 
for its conservation. The range of the fluted kidneyshell has been 
severely curtailed, occupied habitats are limited and isolated, and 
population sizes are generally small (see Summary of Factors Affecting 
the Species). For example, the fluted kidneyshell is no longer believed 
to occur in the Rockcastle, Hiwassee, Elk, Holston, or French Broad 
rivers. The inclusion of essential unoccupied areas will provide 
habitat for population reintroduction and will decrease the risk of 
extinction. Based on the best scientific data available, we believe 
these areas not currently occupied by the fluted kidneyshell are 
essential for their conservation.
    However, we eliminated from consideration as unoccupied critical 
habitat the Red and Harpeth River drainages; the Caney Fork, mainstem 
Cumberland, mainstem Tennessee, Tellico, Obey, South Fork Powell, South 
Fork Holston, West Prong Little Pigeon, Little Tennessee Rivers; and 
Kennedy, Pittman, Otter, Flint, Sugar, Limestone, Shoal, Puckell, North 
Fork, and Big Rock Creeks for both of these mussels. These areas are 
not essential for the conservation of the mussels and were eliminated 
from consideration because of stream channel alterations, a limited 
amount of available habitat coupled with being isolated from other 
populations, a lack of a native mussel fauna, poor habitat or water 
quality, or a lack of available fish hosts.
    All of the stream habitat areas proposed as unoccupied critical 
habitat have sufficient water quality and fish hosts necessary for the 
fluted kidneyshell. The stream reaches also lack major anthropogenic 
disturbances, and have potential for reoccupation by the species 
through future reintroduction efforts. Based on the above factors, all 
unoccupied stream reaches included in the proposed designations for the 
fluted kidneyshell are essential for its conservation.
    Following the identification of occupied and unoccupied stream 
reaches, the next step was to delineate the probable upstream and 
downstream extent of each species' distribution. We used USGS 1:100,000 
digital stream maps to delineate these boundaries of proposed critical 
habitat units according to the criteria explained below. The upstream 
boundary of a unit in a stream is the first perennial, named tributary 
confluence, a road-crossing bridge, or a permanent barrier to fish 
passage (such as a dam) above the upstream-most current occurrence 
record. The confluence of a tributary typically marks a significant 
change in the size of the stream and is a logical and recognizable 
upstream terminus. When a named tributary was not available, a road-
crossing bridge was used to mark the boundary. Likewise, a dam or other 
barrier to fish passage marks the upstream extent to which mussels may 
disperse via their fish hosts. The downstream boundary of a unit in a 
stream is the confluence of a named tributary, or the upstream extent 
of an impoundment, below the downstream-most occurrence record. In the 
unit descriptions, distances between landmarks marking the upstream or 
downstream extent of a stream segment are given in river kilometers and 
equivalent miles, as measured tracing the course of the stream, not 
straight-line distance.
    Because mussels are naturally restricted by certain physical 
conditions within a stream reach (i.e., flow, substrate), they may be 
unevenly distributed within these habitat units. Uncertainty on 
upstream and downstream distributional limits of some populations may 
have resulted in small areas of occupied habitat excluded from, or 
areas of unoccupied habitat included in, the designation. We recognize 
that both historical and recent collection records upon which we relied 
are incomplete, and that there may be river segments or small 
tributaries not included in this proposed designation that harbor 
small, limited populations of one or both species considered in this 
designation, or that others may become suitable in the future. The 
exclusion of such areas does not diminish their potential individual or 
cumulative importance to the conservation of these species. However, we 
believe that, with proper management, each of the 37 critical habitat 
units (24 fluted kidneyshell units, and 13 slabside pearlymussel units; 
10 overlap between the two species) are capable of supporting one or 
both of these mussel species, and that populations within occupied 
units will serve as source populations for artificial reintroduction 
into unoccupied units, as well as assisted or natural migration into 
adjacent undesignated or designated streams within each river drainage. 
The habitat areas contained within the units described below constitute 
our best evaluation of areas needed for the conservation of these 
species at this time. Critical habitat may be revised for any or all of 
these species should new information become available.
    The areas proposed for critical habitat below include only stream 
channels within the ordinary high-water line, and do not contain 
developed areas or structures. The scale of the maps we prepared under 
the parameters for publication within the Code of Federal Regulations 
may not reflect the exclusion of such developed lands. Any such lands 
inadvertently left inside critical habitat boundaries shown on the maps 
of this proposed rule have been excluded by text in the proposed rule 
and are not proposed for designation as critical habitat. Therefore, if 
the critical habitat is finalized as proposed, a Federal action 
involving these lands would not trigger section 7 consultation with 
respect to critical habitat and the requirement of no adverse 
modification unless the specific action would affect the PBFs in the 
adjacent critical habitat.
    The critical habitat designation is defined by the map or maps, as 
modified by any accompanying regulatory text, presented at the end of 
this document in the rule portion. We include more detailed information 
on the boundaries of the critical habitat designation in the preamble 
of this document. We will make the coordinates or plot points or both 
on which each map is based available to the public on https://www.regulations.gov at Docket No. FWS-R4-ES-2012-0004, on our Internet 
site at https://www.fws.gov/cookeville, and at

[[Page 60827]]

the Fish and Wildlife office responsible for the designation (see FOR 
FURTHER INFORMATION CONTACT above).

Proposed Critical Habitat Designation

    In total, we are proposing a total of 37 critical habitat units 
encompassing approximately 2,218 rkm (1,380 rmi) in Alabama, Kentucky, 
Mississippi, Tennessee, and Virginia--10 of the units overlap and are 
proposed as critical habitat for both species. For the fluted 
kidneyshell, we are proposing 24 critical habitat units encompassing 
approximately 1,899 rkm (1,181 rmi) of stream channel in Alabama, 
Kentucky, Tennessee, and Virginia. The critical habitat areas we 
describe below constitute our current best assessment of areas that 
meet the definition of critical habitat for the fluted kidneyshell. The 
24 areas we propose as critical habitat are as follows: (1) Horse Lick 
Creek, KY; (2) Middle Fork Rockcastle River, KY; (3) Rockcastle River, 
KY; (4) Buck Creek, KY; (5) Rock Creek, KY; (6) Little South Fork 
Cumberland River, KY; (7) Big South Fork Cumberland River, KY, TN; (8) 
Wolf River and Town Branch, TN; (9) West Fork Obey River, TN; (10) 
Indian Creek, VA; (11) Little River [tributary to the Clinch River], 
VA; (12) North Fork Holston River, VA; (13) Middle Fork Holston River, 
VA; (14) Big Moccasin Creek, VA; (15) Copper Creek, VA; (16) Clinch 
River, TN, VA; (17) Powell River, TN, VA; (18) Nolichucky River, TN; 
(19) Holston River, TN; (20) French Broad River, TN; (21) Hiwassee 
River, TN; (22) Elk River, AL, TN; (23) Duck River, TN; and (24) 
Buffalo River, TN.
    We are proposing 13 critical habitat units encompassing 
approximately 1,562 rkm (970 rmi) of stream channel in Alabama, 
Mississippi, Tennessee, and Virginia for the slabside pearlymussel. The 
critical habitat areas we describe below constitute our current best 
assessment of areas that meet the definition of critical habitat for 
the slabside pearlymussel. The 13 areas we propose as critical habitat 
are as follows: (1) North Fork Holston River, VA; (2) Middle Fork 
Holston River, VA; (3) Big Moccasin Creek, VA; (4) Clinch River, TN, 
VA; (5) Powell River, TN, VA; (6) Nolichucky River, TN; (7) Hiwassee 
River, TN; (8) Sequatchie River, TN; (9) Paint Rock River, AL; (10) Elk 
River, AL, TN; (11) Bear Creek, AL, MS; (12) Duck River, TN; and (13) 
Buffalo River, TN.
    Unit name, location, and the approximate stream length of each 
proposed critical habitat unit are shown in Table 3 for the fluted 
kidneyshell and Table 4 for the slabside pearlymussel. The proposed 
critical habitat units include the stream channels within the ordinary 
high-water line only. For this purpose, we have applied the definition 
found at 33 CFR 329.11, and consider the ordinary high-water mark on 
nontidal rivers to be the line on the shore established by the 
fluctuations of water and indicated by physical characteristics, such 
as a clear, natural line impressed on the bank; shelving; changes in 
the character of soil; destruction of terrestrial vegetation; the 
presence of litter and debris; or other appropriate means that consider 
the characteristics of the surrounding areas.
    States were granted ownership of lands beneath navigable waters up 
to the ordinary high-water line upon achieving Statehood (Pollard v. 
Hagan, 44 U.S. (3 How.) 212 (1845)). Prior sovereigns or the States may 
have made grants to private parties that included lands below the 
ordinary high-water mark of some navigable waters that are included in 
this proposal. We believe that most, if not all, lands beneath the 
navigable waters included in this proposed rule are owned by the 
States. The lands beneath most nonnavigable waters included in this 
proposed rule are in private ownership. In Alabama, the riparian 
landowner owns the stream to the middle of the channel for non-
navigable streams. Riparian lands along the waters are either in 
private ownership, or are owned by county, State, or Federal entities. 
Lands under county, State, and Federal ownership consist of managed 
conservation areas, and are considered to have some level of 
protection.

   Table 3--Fluted Kidneyshell Occupancy Status and Riparian Lands Ownership Adjacent to the Proposed Critical
                                                  Habitat Units
----------------------------------------------------------------------------------------------------------------
                                                                               Federal, state,
                                                                 Private        county, city    Total length rkm
       Unit             Location       Occupied by species    ownership rkm     ownership rkm         (rmi)
                                                                  (rmi)             (rmi)
----------------------------------------------------------------------------------------------------------------
FK1..............  Horse Lick Creek,   Yes................         3.6 (2.3)       15.8 (10.1)       19.4 (12.4)
                    KY.
FK2..............  Middle Fork         Yes................         6.0 (3.7)         6.5 (4.0)        12.5 (7.7)
                    Rockcastle River,
                    KY.
FK3..............  Rockcastle River,   No.................        11.7 (7.3)       58.2 (36.2)       69.9 (43.5)
                    KY.
FK4..............  Buck Creek, KY....  Yes................       59.7 (37.1)         1.3 (0.8)       61.0 (37.9)
FK5..............  Rock Creek, KY....  Yes................         1.5 (0.9)       17.7 (11.0)       19.2 (11.9)
FK6..............  Little South Fork   Yes................       61.1 (38.0)         4.4 (2.7)       65.5 (40.7)
                    Cumberland River,
                    KY.
FK7..............  Big South Fork      Yes................         1.5 (1.0)       90.0 (55.9)       91.5 (56.9)
                    Cumberland River,
                    KY, TN.
FK8..............  Wolf River and      Yes................       38.7 (24.0)         5.7 (3.5)       44.4 (27.5)
                    Town Branch, TN.
FK9..............  West Fork Obey      Yes................       19.3 (12.0)                 0       19.3 (12.0)
                    River, TN.
FK10.............  Indian Creek, VA..  Yes................         6.7 (4.2)                 0         6.7 (4.2)
FK11.............  Little River, VA..  Yes................       50.4 (31.3)                 0       50.4 (31.3)
FK12.............  North Fork Holston  Yes................       66.4 (41.3)         0.9 (0.5)       67.3 (41.8)
                    River, VA.
FK13.............  Middle Fork         Yes................       89.0 (55.3)                 0       89.0 (55.3)
                    Holston River, VA.
FK14.............  Big Moccasin        No.................       33.1 (20.6)                 0       33.1 (20.6)
                    Creek, VA.
FK15.............  Copper Creek, VA..  Yes................       55.5 (34.5)                 0       55.5 (34.5)
FK16.............  Clinch River, TN,   Yes................     256.3 (159.2)         6.4 (4.0)     262.7 (163.2)
                    VA.
FK17.............  Powell River, TN,   Yes................      152.4 (94.7)         0.3 (0.2)      152.7 (94.9)
                    VA.
FK18.............  Nolichucky River,   No.................       50.9 (31.6)         0.9 (0.6)       51.9 (32.2)
                    TN.
FK19.............  Holston River, TN.  No.................       85.1 (52.9)                 0       85.1 (52.9)
FK20.............  French Broad        No.................       54.4 (33.8)         1.7 (1.1)       56.1 (34.9)
                    River, TN.
FK21.............  Hiwassee River, TN  No.................                 0       24.4 (15.2)       24.4 (15.2)
FK22.............  Elk River, AL, TN.  No.................     162.8 (101.2)         1.5 (0.9)     164.3 (102.1)
FK23.............  Duck River, TN....  Yes................     284.0 (176.5)       63.5 (39.4)     347.5 (215.9)
FK24.............  Buffalo River, TN.  No.................       50.0 (31.0)                 0       50.0 (31.0)
                                                           -----------------------------------------------------
    Total........  ..................  ...................  ................  ................           1,899.4
                                                                                                       (1,180.5)
----------------------------------------------------------------------------------------------------------------


[[Page 60828]]


   Table 4--Occupancy and Ownership of Riparian Lands Adjacent to the Proposed Critical Habitat Units for the
                                              Slabside Pearlymussel
----------------------------------------------------------------------------------------------------------------
                                                                               Federal, state,
                                                                 Private        county, city    Total length rkm
       Unit             Location             Occupied         ownership rkm     ownership rkm         (rmi)
                                                                  (rmi)             (rmi)
----------------------------------------------------------------------------------------------------------------
SP1..............  North Fork Holston  Yes................       66.4 (41.3)         0.9 (0.5)       67.3 (41.8)
                    River, VA.
SP2..............  Middle Fork         Yes................       89.0 (55.3)                 0       89.0 (55.3)
                    Holston River, VA.
SP3..............  Big Moccasin        Yes................       33.1 (20.6)                 0       33.1 (20.6)
                    Creek, VA.
SP4..............  Clinch River, TN,   Yes................     256.3 (159.2)         6.4 (4.0)     262.7 (163.2)
                    VA.
SP5..............  Powell River, TN,   Yes................      152.4 (94.7)         0.3 (0.2)      152.7 (94.9)
                    VA.
SP6..............  Nolichucky River,   Yes................       50.9 (31.6)         0.9 (0.6)       51.9 (32.2)
                    TN.
SP7..............  Hiwassee River, TN  Yes................                 0       24.4 (15.2)       24.4 (15.2)
SP8..............  Sequatchie River,   Yes................      151.5 (94.1)                 0      151.5 (94.1)
                    TN.
SP9..............  Paint Rock River,   Yes................      119.2 (74.1)         5.8 (3.6)      125.0 (77.7)
                    AL.
SP10.............  Elk River, AL, TN.  Yes................     162.8 (101.2)         1.5 (0.9)     164.3 (102.1)
SP11.............  Bear Creek, AL, MS  Yes................       36.3 (22.5)         6.1 (3.8)       42.4 (26.3)
SP12.............  Duck River, TN....  Yes................     284.0 (176.5)       63.5 (39.4)     347.5 (215.9)
SP13.............  Buffalo River, TN.  Yes................       50.0 (31.0)                 0       50.0 (31.0)
                                                           -----------------------------------------------------
    Total........  ..................  ...................  ................  ................   1,561.8 (970.3)
----------------------------------------------------------------------------------------------------------------

    Eleven critical habitat units proposed for both the fluted 
kidneyshell and slabside pearlymussel are currently designated as 
critical habitat under the Act for other species, including the purple 
bean (Villosa perpurpurea), oyster mussel (Epioblasma capsaeformis), 
Cumberlandian combshell (E. brevidens), Cumberland elktoe (Alasmidonta 
atropurpurea), rough rabbitsfoot (Quadrula cylindrica strigillata), 
slender chub (Erimystax cahni), and yellowfin madtom (Noturus 
flavipinnis) (42 FR 45526, 42 FR 47840, 69 FR 53136), or are proposed 
as critical habitat under the Act for the rabbitsfoot (Q. c. 
cylindrica) (see Table 5). The proposed units for the fluted 
kidneyshell and slabside pearlymussel completely or partially overlap 
existing units in the Powell, Clinch, Nolichucky, Big South Fork 
Cumberland, Duck, and Paint Rock Rivers and in the Buck, Rock, Indian, 
Copper, and Bear Creeks; however, the exact unit descriptions (lengths) 
differ due to mapping refinement since the earlier designations. No 
other critical habitat units proposed for these species have been 
designated or proposed as critical habitat for other species under the 
Act.
    Three critical habitat units proposed for the fluted kidneyshell 
and slabside pearlymussel are currently designated under section 10(j) 
of the Act as nonessential experimental populations for other species, 
including the yellowfin madtom in the North Fork Holston River, VA; and 
15 mussels, 1 snail, and 5 fishes in the lower Holston and French Broad 
Rivers, TN (53 FR 29335, 72 FR 52434, see Table 5).
    All of the critical habitat units proposed for the fluted 
kidneyshell and slabside pearlymussel contain historical or extant 
records of federally listed or proposed species, except for the Wolf 
River and Town Branch and West Fork Obey River, TN (see Table 6).

     Table 5--Critical Habitat Units Proposed for the Fluted Kidneyshell and Slabside Pearlymussel Which Are
             Currently Designated or Proposed as Critical Habitat for Other Federally Listed Species
----------------------------------------------------------------------------------------------------------------
                                                                              Nonessential          Length of
        Unit (Unit No.)                Species        Critical habitat        experimental         overlap rkm
                                                                               population             (rmi)
----------------------------------------------------------------------------------------------------------------
Buck Creek (FK4)...............  Oyster mussel,      69 FR 53136.......  ......................  61 (38)
                                  Cumberlandian
                                  combshell.
Rock Creek (FK5)...............  Cumberland elktoe.  69 FR 53136.......  ......................  19 (12)
Big South Fork Cumberland River  Oyster mussel,      69 FR 53136.......  ......................  92 (57)
 (FK7).                           Cumberlandian
                                  combshell,
                                  Cumberland elktoe.
Indian Creek (FK10)............  Purple bean,......  69 FR 53136.......  ......................  7 (4)
                                 Oyster mussel,
                                  Cumberlandian
                                  combshell, Rough
                                  rabbitsfoot.
North Fork Holston River (FK12,  Yellowfin madtom..  ..................  53 FR 29335...........  58 (36)
 SP1).
Copper Creek (FK15)............  Purple bean,        69 FR 53136,......  ......................  21 (13)
                                  Oyster mussel,     42 FR 45526,......                          56 (35)
                                  Cumberlandian      42 FR 47840.......                          56 (35)
                                  combshell, Rough   ..................
                                  rabbitsfoot,
                                  Yellowfin madtom.
Clinch River (FK16, SP4).......  Purple bean,        69 FR 53136,......  ......................  263 (163)
                                  Oyster mussel,     42 FR 45526,......                          263 (163)
                                  Cumberlandian      42 FR 47840.......                          263 (163)
                                  combshell, Rough
                                  rabbitsfoot,
                                  Slender chub,
                                  Yellowfin madtom.
Powell River (FK17, SP5).......  Purple bean,        69 FR 53136,......  ......................  153 (95)
                                  Cumberlandian      42 FR 45526,......                          153 (95)
                                  combshell, Oyster  42 FR 47840.......                          153 (95)
                                  mussel, Rough
                                  rabbitsfoot,
                                  Slender chub,
                                  Yellowfin madtom.

[[Page 60829]]

 
Nolichucky River (FK18, SP6)...  Oyster mussel,      69 FR 53136.......  ......................  8 (5)
                                  Cumberlandian
                                  combshell.
Holston River (FK19)...........  15 Mussels, 1       ..................  72 FR 52434...........  85 (53)
                                  Snail, and 5
                                  Fishes.
French Broad River (FK20)......  15 Mussels, 1       ..................  72 FR 52434...........  56 (35)
                                  Snail, and 5
                                  Fishes.
Paint Rock River (SP9).........  Rabbitsfoot.......  TBD...............  ......................  80 (50)
Bear Creek (SP11)..............  Oyster mussel,      69 FR 53136.......  ......................  42 (26)
                                  Cumberlandian                                                  234 (136)
                                  combshell,
                                  Rabbitsfoot.
Duck River (FK23, SP12)........  Oyster mussel,      69 FR 53136.......  ......................  74 (46)
                                  Cumberlandian                                                  234 (146)
                                  combshell,
                                  Rabbitsfoot.
                                --------------------------------------------------------------------------------
    Total......................  ..................  ..................  ......................  1221 (760)
----------------------------------------------------------------------------------------------------------------


 Table 6--Federally Listed or Proposed Species With Historical or Extant
 Records From the Proposed Critical Habitat Unit Streams for the Fluted
                  Kidneyshell and Slabside Pearlymussel
------------------------------------------------------------------------
                                         Federally listed or proposed
                                                species present
       Unit             Location     -----------------------------------
 
------------------------------------------------------------------------
FK1...............  Horse Lick        Cumberland bean.  Villosa
                     Creek, KY.                          trabalis.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
FK2...............  Middle Fork       Cumberland bean.  Villosa
                     Rockcastle                          trabalis.
                     River, KY.
FK3...............  Rockcastle        Cumberland bean.  Villosa
                     River, KY.                          trabalis.
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
FK4...............  Buck Creek, KY..  Cumberland bean.  Villosa
                                                         trabalis.
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
FK5...............  Rock Creek, KY..  Cumberland        Alasmidonta
                                       elktoe.           atropurpurea.
FK6...............  Little South      Cumberland bean.  Villosa
                     Fork Cumberland                     trabalis.
                     River, KY.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      palezone shiner.  Notropis
                                                         albizonatus.
FK7...............  Big South Fork    Cumberland bean.  Villosa
                     Cumberland                          trabalis.
                     River, KY.
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      Cumberland        Alasmidonta
                                       elktoe.           atropurpurea.
                                      dromedary         Dromus dromas.
                                       pearlymussel.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      spectaclecase...  Cumberlandia
                                                         monodonta.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
                                      duskytail darter  Etheostoma
                                                         percnurum.
FK8...............  Wolf River and    None............
                     Town Branch, TN.
FK9...............  West Fork Obey    None............
                     River, TN.
FK10..............  Indian Creek, VA  purple bean.....  Villosa
                                                         perpurpurea.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
FK11..............  Little River, VA  finerayed pigtoe  Fusconaia
                                                         cuneolus.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
FK12, SP1.........  North Fork        littlewing        Pegias fabula.
                     Holston River,    pearlymussel.
                     VA.
                                      purple bean.....  Villosa
                                                         perpurpurea.
                                      rough             Quadrula
                                       rabbitsfoot.      cylindrica
                                                         strigillata.
                                      shiny pigtoe....  Fusconaia cor.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      spotfin chub....  Erimonax
                                                         monachus.
FK13, SP2.........  Middle Fork       littlewing        Pegias fabula.
                     Holston River,    pearlymussel.
                     VA.
                                      shiny pigtoe....  Fusconaia cor.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      spotfin chub....  Erimonax
                                                         monachus.

[[Page 60830]]

 
FK14, SP3.........  Big Moccasin      finerayed pigtoe  Fusconaia
                     Creek, VA.                          cuneolus.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      rough             Quadrula
                                       rabbitsfoot.      cylindrica
                                                         strigillata.
FK15..............  Copper Creek, VA  finerayed pigtoe  Fusconaia
                                                         cuneolus.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      purple bean.....  Villosa
                                                         perpurpurea.
                                      rough             Quadrula
                                       rabbitsfoot.      cylindrica
                                                         strigillata.
                                      shiny pigtoe....  Fusconaia cor.
                                      duskytail darter  Etheostoma
                                                         percnurum
                    ................  yellowfin madtom  Noturus
                                                         flavipinnis.
FK16, SP4.........  Clinch River,     Appalachian       Quadrula sparsa.
                     TN, VA.           monkeyface.
                                      birdwing          Lemiox rimosus.
                                       pearlymussel.
                                      cracking          Hemistena lata.
                                       pearlymussel.
                                      Cumberland bean.  Villosa
                                                         trabalis.
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      Cumberland        Quadrula
                                       monkeyface.       intermedia.
                                      dromedary         Dromus dromas.
                                       pearlymussel.
                                      fanshell........  Cyprogenia
                                                         stegaria.
                                      finerayed pigtoe  Fusconaia
                                                         cuneolus.
                                      green blossom     Epioblasma
                                       pearlymussel.     torulosa
                                                         gubernaculum.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      pink mucket.....  Lampsilis
                                                         abrupta.
                                      purple bean.....  Villosa
                                                         perpurpurea.
                                      rayed bean......  Villosa fabalis.
                                      rough pigtoe....  Pleurobema
                                                         plenum.
                                      rough             Quadrula
                                       rabbitsfoot.      cylindrica
                                                         strigillata.
                                      sheepnose.......  Plethobasus
                                                         cyphyus.
                                      shiny pigtoe....  Fusconaia cor.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      spectaclecase...  Cumberlandia
                                                         monodonta.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      pygmy madtom....  Noturus
                                                         stanauli.
                                      slender chub....  Erimystax cahni.
FK17, SP5.........  Powell River,     Appalachian       Quadrula sparsa.
                     TN, VA.           monkeyface.
                                      birdwing          Lemiox rimosus.
                                       pearlymussel.
                                      cracking          Hemistena lata.
                                       pearlymussel.
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      Cumberland        Quadrula
                                       monkeyface.       intermedia.
                                      dromedary         Dromus dromas.
                                       pearlymussel.
                                      finerayed pigtoe  Fusconaia
                                                         cuneolus.
                                      green blossom     Epioblasma
                                       pearlymussel.     torulosa
                                                         gubernaculum.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      purple bean.....  Villosa
                                                         perpurpurea.
                                      rayed bean......  Villosa fabalis.
                                      rough             Quadrula
                                       rabbitsfoot.      cylindrica
                                                         strigillata.
                                      sheepnose.......  Plethobasus
                                                         cyphyus.
                                      shiny pigtoe....  Fusconaia cor.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      spectaclecase...  Cumberlandia
                                                         monodonta.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
                                      white wartyback.  Plethobasus
                                                         cicatricosus.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      slender chub....  Erimystax cahni.
                                      yellowfin madtom  Noturus
                                                         flavipinnis.
FK18, SP6.........  Nolichucky        Cumberlandian     Epioblasma
                     River, TN.        combshell.        brevidens.
                                      green blossom     Epioblasma
                                       pearlymussel.     torulosa
                                                         gubernaculum.
                                      pink mucket.....  Lampsilis
                                                         abrupta.
                                      rayed bean......  Villosa fabalis.
                                      spectaclecase...  Cumberlandia
                                                         monodonta.
                                      snail darter....  Percina tanasi.
FK19..............  Holston River,    Appalachian       Quadrula sparsa.
                     TN.               Monkeyface.
                                      birdwing          Lemiox rimosus.
                                       pearlymussel.
                                      cracking          Hemistena lata.
                                       pearlymussel.

[[Page 60831]]

 
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      Cumberland        Quadrula
                                       monkeyface.       intermedia.
                                      dromedary         Dromus dromas.
                                       pearlymussel.
                                      green blossom     Epioblasma
                                       pearlymussel.     torulosa
                                                         gubernaculum.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      ring pink.......  Obovaria retusa.
                                      sheepnose.......  Plethobasus
                                                         cyphyus.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      spectaclecase...  Cumberlandia
                                                         monodonta.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
                                      turgid blossom    Epioblasma
                                       pearlymussel.     turgidula.
                                      white wartyback.  Plethobasus
                                                         cicatricosus.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      slender chub....  Erimystax cahni.
                                      snail darter....  Percina tanasi.
FK20..............  French Broad      cracking          Hemistena lata.
                     River, TN.        pearlymussel.
                                      dromedary         Dromus dromas.
                                       pearlymussel.
                                      fanshell........  Cyprogenia
                                                         stegaria.
                                      orangefoot        Plethobasus
                                       pimpleback.       cooperianus.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      pink mucket.....  Lampsilis
                                                         abrupta.
                                      ring pink.......  Obovaria retusa.
                                      rough pigtoe....  Pleurobema
                                                         plenum.
                                      sheepnose.......  Plethobasus
                                                         cyphyus.
                                      shiny pigtoe....  Fusconaia cor.
                                      tubercled         Epioblasma
                                       blossom           torulosa
                                       pearlymussel.     torulosa.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      snail darter....  Percina tanasi.
FK21, SP7.........  Hiwassee River,   Appalachian       Quadrula sparsa.
                     TN.               monkeyface.
                                      Cumberland bean.  Villosa
                                                         trabalis.
                                      dromedary         Dromus dromas.
                                       pearlymussel.
                                      orangefoot        Plethobasus
                                       pimpleback.       cooperianus.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      rough pigtoe....  Pleurobema
                                                         plenum.
                                      sheepnose.......  Plethobasus
                                                         cyphyus.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
                                      tubercled         Epioblasma
                                       blossom           torulosa
                                       pearlymussel.     torulosa.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
SP8...............  Sequatchie        Anthony's         Athearnia
                     River, TN.        riversnail.       anthonyi.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      spectaclecase...  Cumberlandia
                                                         monodonta.
                                      snail darter....  Percina tanasi.
SP9...............  Paint Rock        Alabama           Lampsilis
                     River, AL.        lampmussel.       virescens.
                                      Cumberland bean.  Villosa
                                                         trabalis.
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      finerayed pigtoe  Fusconaia
                                                         cuneolus.
                                      pale lilliput...  Toxolasma
                                                         cylindrellus.
                                      pink mucket.....  Lampsilis
                                                         abrupta.
                                      shiny pigtoe....  Fusconaia cor.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      palezone shiner.  Notropis
                                                         albizonatus.
                                      snail darter....  Percina tanasi.
                                      rabbitsfoot.....  Quadrula
                                                         cylindrica
                                                         cylindrica.
FK22, SP10........  Elk River, AL,    Alabama           Lampsilis
                     TN.               lampmussel.       virescens.
                                      birdwing          Lemiox rimosus.
                                       pearlymussel.
                                      cracking          Hemistena lata.
                                       pearlymussel.
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      Cumberland        Quadrula
                                       monkeyface.       intermedia.
                                      dromedary         Dromus dromas.
                                       pearlymussel.
                                      fanshell........  Cyprogenia
                                                         stegaria.
                                      finerayed pigtoe  Fusconaia
                                                         cuneolus.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      pale lilliput...  Toxolasma
                                                         cylindrellus.
                                      rabbitsfoot.....  Quadrula c.
                                                         cylindrica.
                                      rayed bean......  Villosa fabalis.
                                      shiny pigtoe....  Fusconaia cor.

[[Page 60832]]

 
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      spectaclecase...  Cumberlandia
                                                         monodonta.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
                                      tubercled         Epioblasma
                                       blossom           torulosa
                                       pearlymussel.     torulosa.
                                      turgid blossom    Epioblasma
                                       pearlymussel.     turgidula.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      boulder darter..  Etheostoma
                                                         wapiti.
                                      snail darter....  Percina tanasi.
SP11..............  Bear Creek, AL,   Cumberlandian     Epioblasma
                     MS.               combshell.        brevidens.
                                      finerayed pigtoe  Fusconaia
                                                         cuneolus.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      pink mucket.....  Lampsilis
                                                         abrupta.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      turgid blossom    Epioblasma
                                       pearlymussel.     turgidula.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      rabbitsfoot.....  Quadrula c.
                                                         cylindrica.
FK23, SP12........  Duck River, TN..  birdwing          Lemiox rimosus.
                                       pearlymussel.
                                      clubshell.......  Pleurobema
                                                         clava.
                                      cracking          Hemistena lata.
                                       pearlymussel.
                                      Cumberlandian     Epioblasma
                                       combshell.        brevidens.
                                      Cumberland        Quadrula
                                       monkeyface.       intermedia.
                                      littlewing        Pegias fabula.
                                       pearlymussel.
                                      orangefoot        Plethobasus
                                       pimpleback.       cooperianus.
                                      oyster mussel...  Epioblasma
                                                         capsaeformis.
                                      pale lilliput...  Toxolasma
                                                         cylindrellus.
                                      pink mucket.....  Lampsilis
                                                         abrupta.
                                      rayed bean......  Villosa fabalis.
                                      sheepnose.......  Plethobasus
                                                         cyphyus.
                                      snuffbox........  Epioblasma
                                                         triquetra.
                                      spectaclecase...  Cumberlandia
                                                         monodonta.
                                      tan riffleshell.  Epioblasma
                                                         florentina
                                                         walkeri (=E.
                                                         walkeri).
                                      tubercled         Epioblasma
                                       blossom           torulosa
                                       pearlymussel.     torulosa.
                                      turgid blossom    Epioblasma
                                       pearlymussel.     turgidula.
                                      winged mapleleaf  Quadrula
                                                         fragosa.
                                      yellow blossom..  Epioblasma
                                                         florentina
                                                         florentina.
                                      pygmy madtom....  Noturus
                                                         stanauli.
                                      rabbitsfoot.....  Quadrula c.
                                                         cylindrica.
FK24, SP13........  Buffalo River,    pale lilliput...  Toxolasma
                     TN.                                 cylindrellus.
                                      spotfin chub....  Erimonax
                                                         monachus.
                                      rabbitsfoot.....  Quadrula c.
                                                         cylindrica.
------------------------------------------------------------------------

    For each stream reach proposed as a critical habitat unit, the 
upstream and downstream boundaries are described generally below. More 
precise definitions are provided in the Proposed Regulation 
Promulgation at the end of this proposed rule. Fluted kidneyshell and 
slabside pearlymussel status and distribution for each critical habitat 
unit was previously described in the Background section.

Fluted Kidneyshell and Slabside Pearlymussel Proposed Critical Habitat

    Under the first prong of the Act's definition of critical habitat, 
areas within the geographical area occupied by the species at the time 
it was listed must contain PBFs which are (1) essential to the 
conservation of the species and (2) which may require special 
management considerations or protection. For those units occupied by 
either the fluted kidneyshell, slabside pearlymussel, or both species, 
we describe the principal PCEs essential to the conservation of the 
species and the special management considerations or protections that 
may be needed for each unit below.
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in areas outside the geographical 
area occupied by the species at the time it is listed, upon a 
determination that such areas are essential for the conservation of the 
species. For those units unoccupied by the fluted kidneyshell, or 
slabside pearlymussel, we are proposing to designate these units 
because we have determined that they are essential for the conservation 
of the species due to the need to re-establish the species within other 
portions of its historical range in order to reduce threats from 
stochastic events.
    For five of the units (Big Moccasin Creek, Nolichucky, Hiwassee, 
Elk, and Buffalo Rivers), we are designating critical habitat for the 
slabside pearlymussel under prong one of the Act (occupied), while at 
the same time designating the unit under prong two of the Act for the 
fluted kidneyshell species (unoccupied). Therefore, the principal PCEs 
and special management considerations or protections given for these 
units only apply to the species for which the unit is occupied critical 
habitat (slabside pearlymussel).

[[Page 60833]]

Unit FK1: Horse Lick Creek, Rockcastle and Jackson Counties, Kentucky

    Proposed Unit FK1 encompasses approximately 19 rkm (12 rmi) of 
Horse Lick Creek, in Rockcastle and Jackson Counties, KY. It includes 
the mainstem of Horse Lick Creek from its confluence with the 
Rockcastle River upstream to Clover Bottom Creek. The unit is within 
the Cumberland River system and is proposed critical habitat for the 
fluted kidneyshell. This unit is included in the geographical area 
occupied by the fluted kidneyshell at the time of listing. This unit is 
located almost entirely on private lands; however, approximately 16 rkm 
(10 rmi) are federal lands within the DBNF. Land and resource 
management decisions and activities within the DBNF are guided by 
DBNF's LRMP (USFS 2004a, pp. 1-14).
    The channel within proposed Unit FK1 is relatively stable, with an 
abundance of riffle habitats (PCE 1), with relatively silt-free sand 
and gravel substrates (PCE 2), and adequate instream flows (PCE 3). A 
diverse fish fauna, including fish host(s) for the fluted kidneyshell, 
are known from this unit (PCE 5).
    Within proposed Unit FK1, the fluted kidneyshell and its habitat 
may require special management considerations or protection to address 
potential adverse effects associated with legacy coal mines and coal 
mining activities, silviculture-related activities, natural gas and oil 
exploration activities in headwater reaches, illegal off-road vehicle 
use and other recreational activities, and nonpoint source pollution 
originating in headwater reaches.

Unit FK2: Middle Fork Rockcastle River, Jackson County, Kentucky

    Proposed Unit FK2 includes 12.5 rkm (7.7 rmi) of the Middle Fork 
Rockcastle River from its confluence with the Rockcastle River upstream 
to its confluence with Indian Creek and Laurel Fork in Jackson County, 
KY. The unit is within the Cumberland River system and is proposed as 
occupied critical habitat for the fluted kidneyshell. About half of 
this unit (approximately 6 rkm (4 rmi)) is in public ownership (DBNF), 
and half is in private ownership. Land and resource management 
decisions and activities within the DBNF are guided by DBNF's LRMP 
(USFS 2004a, pp. 1-14).
    The channel within proposed Unit FK2 is relatively stable and has 
an abundance of riffle habitats (PCE 1), with relatively silt-free sand 
and gravel substrates (PCE 2), and adequate instream flows (PCE 3).
    Within this unit, the fluted kidneyshell and its habitat may 
require special management considerations or protection to address 
potential adverse effects caused by resource extraction (coal mining, 
silviculture, natural gas and oil exploration activities), agricultural 
activities (livestock), lack of adequate riparian buffers, construction 
and maintenance of State and county roads, illegal off-road vehicle 
use, nonpoint source pollution arising from a wide variety of human 
activities, and potentially canopy loss caused by infestations of the 
hemlock wooly adelgid, Adelges tsugae, an invasive pest threatening 
eastern hemlock trees (Tsuga canadensis) in the eastern United States. 
Hemlocks are an important component of riparian vegetation throughout 
the range of the two mussels.

Unit FK3: Rockcastle River, Pulaski, Laurel, and Rockcastle Counties, 
Kentucky

    Proposed Unit FK3 includes approximately 70 rkm (43 rmi) of the 
Rockcastle River from the backwaters of Lake Cumberland near its 
confluence with Cane Creek along the Laurel and Pulaski County line, 
KY, upstream to its confluence with Horse Lick Creek along the Laurel 
and Rockcastle County line, KY. The unit is within the Cumberland River 
system and is considered unoccupied by the fluted kidneyshell at the 
time of listing, but within the species' historical range. Live fluted 
kidneyshell have not been collected within proposed Unit 3 since 1911; 
however, it persists in adjacent tributaries such as Horse Lick Creek 
and shell material has been found as recently as 1985 (Wilson and Clark 
1914 and Thompson 1985 in Cicerello 1993, p. 12). In 2010, surveys of 
the Rockcastle River showed that the river had a diverse mussel fauna, 
including the federally endangered Cumberland bean (McGregor 2010, 
unpubl. data).
    We consider this unit essential for the conservation of the fluted 
kidneyshell due to the need to re-establish the species within other 
portions of its historical range in order to reduce threats from 
stochastic events. Therefore, this unit is proposed as unoccupied 
critical habitat for the fluted kidneyshell. A portion of this unit 
(approximately 12 rkm (7 rmi)) is in private ownership, but the 
majority is in public ownership (DBNF). Land and resource management 
decisions and activities within the DBNF are guided by DBNF's LRMP 
(USFS 2004a, pp. 1-14).

Unit FK4: Buck Creek, Pulaski County, Kentucky

    Proposed Unit FK4 includes approximately 61 rkm (38 rmi) of Buck 
Creek from State Route 192 upstream to Route 328, Pulaski County, KY. 
The unit is within the Cumberland River basin and is proposed critical 
habitat for the fluted kidneyshell. This unit is included in the 
geographical area occupied by the species at the time of listing. A 
portion of this unit (1.3 rkm (0.8 rmi)) is in public ownership (DBNF), 
but the majority is in private ownership. Land and resource management 
decisions and activities within the DBNF are guided by DBNF's LRMP 
(USFS 2004a, pp. 1-14). The unit completely overlaps existing critical 
habitat for the oyster mussel and Cumberlandian combshell (69 FR 
53136).
    The channel within proposed Unit FK4 is relatively stable, with 
excellent instream habitat (PCE 1). There is an abundance of riffle 
habitats (PCE 1), with relatively silt-free sand and gravel substrates 
(PCE 2), and adequate instream flows (PCE 3). A diverse fish fauna, 
including fish host(s) for the fluted kidneyshell, are known from this 
unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell and its habitat 
may require special management considerations or protection to address 
potential adverse effects associated with instream gravel mining, 
silviculture-related activities, illegal off-road vehicle use and other 
recreational activities, and nonpoint source pollution from 
agricultural and developmental activities.

Unit FK5: Rock Creek, McCreary County, Kentucky

    Proposed Unit FK5 includes approximately 19 rkm (12 rmi) of Rock 
Creek from its confluence with White Oak Creek upstream to the low 
water crossing at rkm 25.6 (rmi 15.9) in McCreary County, KY. The unit 
is within the Cumberland River system and is proposed critical habitat 
for the fluted kidneyshell. This unit is included in the geographical 
area occupied by the species at the time of listing. A portion of this 
unit (1.5 rkm (0.9 rmi)) is in private ownership, but the majority is 
in public ownership (DBNF). Land and resource management decisions and 
activities within the DBNF are guided by DBNF's LRMP (USFS 2004a, pp. 
1-14). The unit completely overlaps existing critical habitat for the 
Cumberland elktoe (69 FR 53136).
    The channel within proposed Unit FK5 is relatively stable, with 
excellent instream habitat (PCE 1). There is an abundance of riffle 
habitats (PCE 1),

[[Page 60834]]

with relatively silt-free sand and gravel substrates (PCE 2), and 
adequate instream flows (PCE 3). A diverse fish fauna, including fish 
host(s) for the fluted kidneyshell, are known from this unit (PCE 5).
    Within this unit, the fluted kidneyshell and its habitat may 
require special management considerations or protection to address 
potential adverse effects caused by resource extraction (coal mining, 
silviculture, natural gas and oil exploration activities), agricultural 
activities (livestock), lack of adequate riparian buffers, construction 
and maintenance of State and county roads, illegal off-road vehicle 
use, nonpoint source pollution arising from a wide variety of human 
activities, and potentially canopy loss caused by infestations of the 
hemlock wooly adelgid.

Unit FK6: Little South Fork Cumberland River, McCreary and Wayne 
Counties, Kentucky

    Proposed Unit FK6 includes 65.5 rkm (40.7 rmi) of the Little South 
Fork Cumberland River from its confluence with the Big South Fork 
Cumberland River, where it is the dividing line between Wayne and 
McCreary Counties, upstream to its confluence with Dobbs Creek in Wayne 
County, KY. The unit is within the Cumberland River system and is 
proposed critical habitat for the fluted kidneyshell. This unit is 
included in the geographical area occupied by the species at the time 
of listing. A portion of this unit (4.4 rkm (2.7 rmi)) is in public 
ownership (DBNF), but the majority is in private ownership. Land and 
resource management decisions and activities within the DBNF are guided 
by DBNF's LRMP (USFS 2004a, pp. 1-14).
    The channel within proposed Unit FK6 is relatively stable, with an 
abundance of riffle habitats (PCE 1), relatively silt-free sand and 
gravel substrates (PCE 2), and adequate instream flows (PCE 3). A 
diverse fish fauna, including fish host(s) for the fluted kidneyshell, 
are known from this unit (PCE 5).
    Within this unit, the fluted kidneyshell and its habitat may 
require special management considerations or protection to address 
potential adverse effects caused by resource extraction (coal mining, 
silviculture, natural gas and oil exploration activities), agricultural 
activities (livestock), lack of adequate riparian buffers, construction 
and maintenance of State and county roads, illegal off-road vehicle 
use, nonpoint source pollution arising from a wide variety of human 
activities, and potentially canopy loss caused by infestations of the 
hemlock wooly adelgid.

Unit FK7: Big South Fork Cumberland River, Fentress, Morgan, and Scott 
Counties, Tennessee, and McCreary County, Kentucky

    Proposed Unit FK7 includes a combined total of 92.0 rkm (57.1 rmi) 
of the Big South Fork of the Cumberland River, Clear Fork of the New 
River, and the New River in Tennessee and Kentucky. Proposed Unit FK7 
includes approximately 45 rkm (28 rmi) of the Big South Fork Cumberland 
River from its confluence with Laurel Crossing Branch downstream of Big 
Shoals, McCreary County, KY, upstream to its confluence with Clear Fork 
and of the New River, Scott County, TN. This unit also includes 32.3 
rkm (20.0 rmi) of Clear Fork from its confluence with the Big South 
Fork and New River in Scott County, TN, upstream to its confluence with 
Crooked Creek along the Fentress and Morgan County line, TN. This unit 
also includes 14.7 rkm (9.1 rmi) of the New River from its confluence 
with the Big South Fork upstream to the Highway 27 Bridge crossing in 
Scott County, TN. The unit is within the Cumberland River system and is 
proposed as occupied critical habitat for the fluted kidneyshell. This 
unit is included in the geographical area occupied by the species at 
the time of listing. A portion of this unit (92 rkm (57 rmi)) has been 
designated as critical habitat for the Cumberlandian combshell, oyster 
mussel, and Cumberland elktoe (69 FR 53136).
    This unit is located almost entirely on federal lands within the 
BSFNRRA. Land and resource management decisions and activities within 
the BSFNRRA are guided by the National Park Service General Management 
Plan, Field Management Plan, and Draft Non-Federal Oil and Gas 
Management Plan (NPS 2005, entire; NPS 2006, pp. 1-12; NPS 2011, 
entire).
    The channel within proposed Unit FK7 is relatively stable, with 
relatively silt-free sand and gravel substrates (PCE 2) and adequate 
instream flows (PCE 3). A diverse fish fauna, including fish host(s) 
for the fluted kidneyshell, are known from this unit (PCE 5).
    Within this unit, the fluted kidneyshell and its habitat may 
require special management considerations or protection to address 
potential adverse effects caused by resource extraction (coal mining, 
silviculture, natural gas and oil exploration activities), lack of 
adequate riparian buffers, construction and maintenance of roads, 
recreational horse riding, illegal off-road vehicle use, nonpoint 
source pollution arising from a wide variety of human activities, and 
potential canopy loss caused by infestations of the hemlock wooly 
adelgid.

Unit FK8: Wolf River and Town Branch, Pickett and Fentress Counties, 
Tennessee

    Proposed Unit FK8 includes 41.0 rkm (25.5 rmi) of the Wolf River 
from its inundation at Dale Hollow Lake in Pickett County, TN, upstream 
to its confluence with Delk Creek in Fentress County, TN, and 3.4 rkm 
(2.0 rmi) of Town Branch from its confluence with Wolf River upstream 
to its headwaters in Pickett County, TN. The unit is within the 
Cumberland River system and is proposed critical habitat for the fluted 
kidneyshell. This unit is included in the geographical area occupied by 
the species at the time of listing. A portion of this unit (6 rkm (4 
rmi)) is in public ownership (Corps lands adjacent to Dale Hollow 
Reservoir and Sgt. Alvin C. York State Historic Park), but the majority 
is in private ownership.
    The channel within proposed Unit FK8 is relatively stable, with 
excellent instream habitat (PCE 1). There is an abundance of riffle 
habitats (PCE 1), with relatively silt-free sand and gravel substrates 
(PCE 2) and adequate instream flows (PCE 3). A diverse fish fauna, 
including fish host(s) for the fluted kidneyshell, are known from this 
unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell and its habitat 
may require special management considerations or protection to address 
potential adverse effects associated with coal mining, silviculture-
related activities, natural gas and oil exploration activities in 
headwater reaches, agricultural activities (livestock), lack of 
adequate riparian buffers, construction and maintenance of State and 
county roads, off-road vehicle use and other recreational activities, 
nonpoint source pollution originating in headwater reaches, and 
potential canopy loss caused by infestations of the hemlock wooly 
adelgid.

Unit FK9: West Fork Obey River, Overton County, Tennessee

    Proposed Unit FK9 includes approximately 19 rkm (12 rmi) of the 
West Fork Obey River from the Highway 52 Bridge crossing upstream to 
its confluence with Dry Hollow Creek in Overton County, TN. The unit is 
within the Cumberland River system and is proposed critical habitat for 
the fluted kidneyshell. This unit is included in the geographical area 
occupied by the species at the time of listing. This unit is located 
almost entirely on private

[[Page 60835]]

land, except for any small amount that is publicly owned in the form of 
bridge crossings and road easements.
    The channel within proposed Unit FK9 is relatively stable, with 
excellent instream habitat (PCE 1). There is an abundance of riffle 
habitats (PCE 1), with relatively silt-free sand and gravel substrates 
(PCE 2), and adequate instream flows (PCE 3). A diverse fish fauna, 
including fish host(s) for the fluted kidneyshell, are known from this 
unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell and its habitat 
may require special management considerations or protection to address 
potential adverse effects associated with coal mining, silviculture-
related activities, natural gas and oil exploration activities in 
headwater reaches, off-road vehicle use and other recreational 
activities, agricultural activities (livestock), lack of adequate 
riparian buffers, construction and maintenance of State and county 
roads, nonpoint source pollution originating in headwater reaches, and 
potential canopy loss caused by infestations of the hemlock wooly 
adelgid.

Unit FK10: Indian Creek, Tazewell County, Virginia

    Proposed Unit FK10 includes 6.7 rkm (4.2 rmi) of Indian Creek from 
its confluence with the Clinch River upstream to the fourth Norfolk 
Southern Railroad crossing at Van Dyke in Tazewell County, VA. The unit 
is within the Tennessee River system and is proposed critical habitat 
for the fluted kidneyshell. This unit is included in the geographical 
area occupied by the species at the time of listing. This unit is 
located almost entirely on private land, except for any small amount 
that is publicly owned in the form of bridge crossings and road 
easements. The unit completely overlaps critical habitat for the 
Cumberlandian combshell, rough rabbitsfoot, purple bean, and oyster 
mussel (69 FR 53136).
    The channel within proposed Unit FK10 is relatively stable, with 
excellent instream habitat (PCE 1). There is an abundance of riffle 
habitats (PCE 1), with relatively silt-free sand and gravel substrates 
(PCE 2), and adequate instream flows (PCE 3). A diverse fish fauna, 
including fish hosts for the fluted kidneyshell, are known from this 
unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell and its habitat 
may require special management considerations or protection to address 
potential adverse effects associated with residential development, coal 
mining, silviculture-related activities, natural gas and oil 
exploration activities in headwater reaches, illegal off-road vehicle 
use and other recreational activities, and nonpoint source pollution 
originating in headwater reaches.

Unit FK11: Little River, Russell and Tazewell Counties, Virginia

    Proposed Unit FK11 includes approximately 50 rkm (31 rmi) of Little 
River from its confluence with the Clinch River in Russell County, VA, 
upstream to its confluence with Liberty and Maiden Spring Creeks in 
Tazewell County, VA. The unit is within the Tennessee River system and 
is proposed critical habitat for the fluted kidneyshell. This unit is 
included in the geographical area occupied by fluted kidneyshell at the 
time of listing. This unit is located almost entirely on private land, 
except for any small amount that is publicly owned in the form of 
bridge crossings and road easements. The Nature Conservancy also owns a 
small portion of adjacent property.
    The channel within proposed Unit FK11 is relatively stable, with 
excellent instream habitat (PCE 1). There is an abundance of riffle 
habitats (PCE 1), with relatively silt-free sand and gravel substrates 
(PCE 2), and adequate instream flows (PCE 3). A diverse fish fauna, 
including fish hosts for the fluted kidneyshell and slabside 
pearlymussel, are known from this unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell and its habitats 
may require special management considerations or protection to address 
potential adverse effects associated with silviculture-related 
activities, natural gas and oil exploration activities in headwater 
reaches, and nonpoint source pollution originating in headwater 
reaches.

Unit FK12 and SP1: North Fork Holston River, Smyth and Bland Counties, 
Virginia

    Proposed Unit FK12 and SP1 includes approximately 67 rkm (42 rmi) 
of the North Fork Holston River from its confluence with Beaver Creek, 
upstream of Saltville, in Smyth County, VA, upstream to Ceres, Bland 
County, VA. The unit is within the Tennessee River system and is 
proposed critical habitat for the fluted kidneyshell and slabside 
pearlymussel. This unit is included in the geographical area occupied 
by both species at the time of listing. This unit is located almost 
entirely on private land, except for any small amount that is publicly 
owned in the form of bridge crossings, road easements, and a small 
portion that is adjacent to the George Washington and Jefferson 
National Forests. The Nature Conservancy and the Virginia Outdoors 
Foundation also own a small portion of adjacent property. A portion of 
this unit (58 rkm (36 rmi)) has been designated as a nonessential 
experimental population (NEP) for the yellowfin madtom (53 FR 29335).
    The channel within proposed Unit FK12 and SP1 is relatively stable, 
with excellent instream habitat (PCE 1). There is an abundance of 
riffle habitats (PCE 1), with relatively silt-free sand and gravel 
substrates (PCE 2), and adequate instream flows (PCE 3). A diverse fish 
fauna, including fish hosts for the fluted kidneyshell and slabside 
pearlymussel, are known from this unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell, slabside 
pearlymussel, and their habitats may require special management 
considerations or protection to address potential adverse effects 
associated with agricultural activities (livestock), silviculture-
related activities, natural gas and oil exploration activities in 
headwater reaches, lack of adequate riparian buffers, construction and 
maintenance of State and county roads, and nonpoint source pollution 
originating in headwater reaches.

Unit FK13 and SP2: Middle Fork Holston River, Washington, Smyth, and 
Wythe Counties, Virginia

    Proposed Unit FK13 and SP2 includes approximately 89 rkm (55 rmi) 
of the Middle Fork Holston River from its inundation at South Holston 
Lake in Washington County, VA, upstream to its headwaters in Wythe 
County, VA. The unit is within the Tennessee River system and is 
proposed critical habitat for the fluted kidneyshell and slabside 
pearlymussel. This unit is included in the geographical area occupied 
by both the fluted kidneyshell and slabside pearlymussel at the time of 
listing. This unit is located almost entirely on private land, except 
for any small amount that is publicly owned in the form of bridge 
crossings and road easements.
    The channel within proposed Unit FK13 and SP2 is relatively stable, 
with excellent instream habitat (PCE 1). There is an abundance of 
riffle habitats (PCE 1), with relatively silt-free sand and gravel 
substrates (PCE 2), and adequate instream flows (PCE 3). A diverse fish 
fauna, including fish hosts for the fluted kidneyshell and slabside 
pearlymussel, are known from this unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell, slabside 
pearlymussel, and their habitats may require special management 
considerations or protection to address potential adverse effects 
associated with agricultural

[[Page 60836]]

activities, lack of adequate riparian buffers, silviculture-related 
activities, and nonpoint source pollution.

Unit FK14 and SP3: Big Moccasin Creek, Scott and Russell Counties, 
Virginia

    Proposed Unit FK14 and SP3 includes approximately 33 rkm (21 rmi) 
of Big Moccasin Creek from the Highway 71 Bridge crossing in Scott 
County, VA, upstream to the Route 612 Bridge crossing near Collinwood 
in Russell County, VA. The unit is within the Tennessee River system 
and is proposed as critical habitat for the fluted kidneyshell and 
slabside pearlymussel. This unit is included in the geographical area 
occupied by slabside pearlymussel at the time of listing. This unit is 
considered unoccupied by the fluted kidneyshell, but within the 
species' historical range. Live fluted kidneyshell have not been 
collected in Big Moccasin Creek since the early 1900s (Ortmann 1918, p. 
608). However, this unit is proposed for critical habitat for the 
fluted kidneyshell because it is considered essential for the 
conservation of the species. This unit is located almost entirely on 
private land, except for any small amount that is publicly owned in the 
form of bridge crossings and road easements.
    The channel within proposed Unit FK14 and SP3 is relatively stable, 
with excellent instream habitat (PCE 1). There is an abundance of 
riffle habitats (PCE 1), with relatively silt-free sand and gravel 
substrates (PCE 2), and adequate instream flows (PCE 3). A diverse fish 
fauna, including fish hosts for the slabside pearlymussel, are known 
from this unit (PCE 5).
    Within this proposed unit, the slabside pearlymussel and its 
habitats may require special management considerations or protection to 
address potential adverse effects associated with agricultural 
activities (livestock), lack of adequate riparian buffers, 
silviculture-related activities, natural gas and oil exploration 
activities in headwater reaches, illegal off-road vehicle use and other 
recreational activities, and nonpoint source pollution originating in 
headwater reaches.

Unit FK15: Copper Creek, Scott County, Virginia

    Proposed Unit FK15 includes 55.5 rkm (34.5 rmi) of Copper Creek 
from its confluence with the Clinch River upstream to the Highway 71 
Bridge crossing in Scott County, VA. The unit is within the Tennessee 
River system and is proposed critical habitat for the fluted 
kidneyshell. This unit is included in the geographical area occupied by 
the species at the time of listing. This unit is located almost 
entirely on private land, except for any small amount that is publicly 
owned in the form of bridge crossings and road easements. A portion of 
this unit (21 rkm (13 rmi)) has been designated as critical habitat for 
the Cumberlandian combshell, rough rabbitsfoot, purple bean, and oyster 
mussel, and a portion of this unit (55.5 rkm (34.5 rmi)) has been 
designated as critical habitat for the yellowfin madtom (42 FR 45526, 
42 FR 47840, 69 FR 53136).
    The channel within proposed Unit FK15 is relatively stable, with 
excellent instream habitat (PCE 1). There is an abundance of riffle 
habitats (PCE 1), with relatively silt-free sand and gravel substrates 
(PCE 2), and adequate instream flows (PCE 3). A diverse fish fauna, 
including fish hosts for the fluted kidneyshell, are known from this 
unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell and its habitat 
may require special management considerations or protection to address 
potential adverse effects associated with agricultural activities 
(livestock), silviculture-related activities, lack of adequate riparian 
buffers, construction and maintenance of State and county roads, and 
nonpoint source pollution originating in headwater reaches.

Unit FK16 and SP4: Clinch River, Hancock County, Tennessee, and Scott, 
Russell, and Tazewell Counties, Virginia

    Proposed Unit FK16 and SP4 includes approximately 263 rkm (163 rmi) 
of the Clinch River from rkm 255 (rmi 159) immediately below Grissom 
Island in Hancock County, TN, upstream to its confluence with Indian 
Creek near Cedar Bluff, Tazewell County, VA. The unit is within the 
Tennessee River system and is proposed critical habitat for the fluted 
kidneyshell and slabside pearlymussel. This unit is included in the 
geographical area occupied by both species at the time of listing. 
Approximately 6 rkm (4 rmi) of this unit is in public ownership, 
including portions of the Kyles Ford State Managed Area, George 
Washington National Forest, Jefferson National Forest, Cleveland 
Barrens State Natural Area Preserve (SNAP), and the Pinnacle SNAP. The 
Nature Conservancy also owns a small portion of adjacent property. The 
unit completely overlaps critical habitat for the Cumberlandian 
combshell, rough rabbitsfoot, purple bean, and oyster mussel, and the 
entire length of this unit has been designated as critical habitat for 
the slender chub and yellowfin madtom (42 FR 45526, 42 FR 47840, 69 FR 
53136).
    The channel within proposed Unit FK16 and SP4 is relatively stable, 
with excellent instream habitat (PCE 1). There is an abundance of 
riffle habitats (PCE 1), with relatively silt-free sand and gravel 
substrates (PCE 2), and adequate instream flows (PCE 3). A diverse fish 
fauna, including fish hosts for the fluted kidneyshell and slabside 
pearlymussel, are known from this unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell, slabside 
pearlymussel, and their habitats may require special management 
considerations or protection to address potential adverse effects 
associated with coal mining, silviculture-related activities, natural 
gas and oil exploration activities in headwater reaches, agricultural 
activities (livestock), lack of adequate riparian buffers, construction 
and maintenance of State and county roads, and nonpoint source 
pollution originating in headwater reaches.

Unit FK17 and SP5: Powell River, Claiborne and Hancock Counties, 
Tennessee, and Lee County, Virginia

    Proposed Unit FK17 and SP5 includes approximately 153 rkm (95 rmi) 
of the Powell River from the U.S. 25E Bridge in Claiborne County, TN, 
upstream to rkm 256 (rmi 159) (upstream of Rock Island in the vicinity 
of Pughs) in Lee County, VA. The unit is within the Tennessee River 
system and is proposed critical habitat for the fluted kidneyshell and 
slabside pearlymussel. This unit is included in the geographical area 
occupied by both species at the time of listing. This unit is located 
almost entirely on private land, except for any small amount that is 
publicly owned in the form of bridge crossings, road easements, and a 
small portion that is adjacent to the Cedars SNAP. The Nature 
Conservancy also owns a small portion of adjacent property. The unit 
completely overlaps critical habitat for the Cumberlandian combshell, 
rough rabbitsfoot, purple bean, and oyster mussel, and the entire 
length of this unit has been designated as critical habitat for the 
slender chub and yellowfin madtom (42 FR 45526, 42 FR 47840, 69 FR 
53136).
    The channel within proposed Unit FK17 and SP5 is relatively stable, 
with instream habitat (PCE 1). There is an abundance of riffle habitats 
(PCE 1), with relatively silt-free sand and gravel substrates (PCE 2), 
and adequate instream flows (PCE 3). A diverse fish fauna, including 
fish hosts for the fluted kidneyshell and slabside pearlymussel, are 
known from this unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell, slabside 
pearlymussel, and

[[Page 60837]]

their habitats may require special management considerations or 
protection to address potential adverse effects associated with coal 
mining, silviculture-related activities, natural gas and oil 
exploration activities in headwater reaches, agricultural activities 
(livestock), lack of adequate riparian buffers, construction and 
maintenance of State and county roads, and nonpoint source pollution 
originating in headwater reaches.

Unit FK18 and SP6: Nolichucky River, Cocke, Hamblen, and Greene 
Counties, Tennessee

    Proposed Unit FK18 and SP6 includes approximately 52 rkm (32 rmi) 
of the Nolichucky River from rkm 14 (rmi 9), approximately 0.6 rkm (0.4 
rmi) upstream of Enka Dam, where it divides Hamblen and Cocke Counties, 
TN, upstream to its confluence with Pigeon Creek, just upstream of the 
Highway 321 Bridge crossing, in Greene County, TN. The unit is within 
the Tennessee River system and is proposed critical habitat for the 
fluted kidneyshell and slabside pearlymussel. This unit is included in 
the geographical area occupied by slabside pearlymussel at the time of 
listing. This unit is considered unoccupied by the fluted kidneyshell 
at the time of listing, but within the species' historical range. Live 
fluted kidneyshell have not been collected in the Nolichucky River 
since the mid-1960s (Tennessee Natural Heritage Inventory Program 
Database, accessed 2012). However, the TWRA has reintroduced the 
species into at least two sites in the Nolichucky River by 
translocating adult individuals from the Clinch River (Hubbs 2011, 
unpubl. data). It is not known if the reintroductions have been 
successful. This unit is proposed for critical habitat for the fluted 
kidneyshell because it is considered essential for the conservation of 
the species. This unit is located almost entirely on private land, 
except for any small amount that is publicly owned in the form of 
bridge crossings, road easements, and a small portion that is within 
Mullins Island Wildlife Management Area. A portion of this unit (8 rkm 
(5 rmi)) has been designated as a critical habitat for the oyster 
mussel and Cumberlandian combshell (69 FR 53136).
    The channel within proposed Unit FK18 and SP6 is relatively stable, 
with excellent instream habitat (PCE 1). There is an abundance of 
riffle habitats (PCE 1), with relatively silt-free sand and gravel 
substrates (PCE 2), and adequate instream flows (PCE 3). A diverse fish 
fauna, including fish hosts for the slabside pearlymussel, are known 
from this unit (PCE 5).
    Within this proposed unit, the slabside pearlymussel and its 
habitats may require special management considerations or protection to 
address potential adverse effects associated with agricultural 
activities, silviculture-related activities, rock mining, lack of 
adequate riparian buffers, construction and maintenance of State and 
county roads, and nonpoint source pollution originating in headwater 
reaches.

Unit FK19: Holston River, Knox, Grainger, and Jefferson Counties, 
Tennessee

    Proposed Unit FK19 includes approximately 85 rkm (53 rmi) of the 
Holston River from its confluence with the French Broad River in Knox 
County, TN, upstream to the base of Cherokee Dam at rkm 83.7 (rmi 52.3) 
along the Grainger and Jefferson County, TN, line. The unit is within 
the Tennessee River system. This unit is considered unoccupied by the 
fluted kidneyshell and slabside pearlymussel, but within the species' 
historical ranges. Live fluted kidneyshell have not been collected in 
the Holston River since the early 1900s (Ortmann 1918, p. 614). As 
discussed below, we consider Unit FK19 essential for the conservation 
of the fluted kidneyshell, but not the slabside pearlymussel, and so it 
is proposed as critical habitat only for the fluted kidneyshell. This 
unit is located almost entirely on private land, except for any small 
amount that is publicly owned in the form of bridge crossings and road 
easements. The unit completely overlaps a designated nonessential 
experimental population for 15 mussels, 1 snail, and 5 fishes (72 FR 
52434).
    We consider this unit essential for the conservation of the fluted 
kidneyshell due to the need to re-establish the species within other 
portions of its historical range in order to reduce threats from 
stochastic events. Although live fluted kidneyshell have not been 
collected in the Holston River since the early 1900s (Ortmann 1918, p. 
614), TVA has improved conditions for aquatic species within this unit. 
Between 1988 and 1995, TVA implemented reservoir release improvements 
below Cherokee Dam on the Holston River. These improvements included 
the establishment of minimum flows and increasing the amount of 
dissolved oxygen in the tailwater below the reservoir (Scott et al. 
1996, p. 21).
    The unit does currently support populations of three federally 
listed species (threatened snail darter and endangered pink mucket and 
sheepnose). In addition, other mussel species co-occur with these 
species along with a diverse fish fauna, including hosts for the fluted 
kidneyshell. These host fishes are bottom-dwelling species that are 
able to move into refugia of low flows during high discharges from the 
hydropower dam upstream. Therefore, the fluted kidneyshell glochidia 
may come into contact and infest the host fishes. The slabside 
pearlymussel and its host fishes are known from the French Broad River 
drainage; however, hydropower operations make this habitat unsuitable 
for mid-water column fishes, such as the shiners that are hosts for the 
slabside pearlymussel (Layzer and Scott 2006, pp. 481, 488-9). 
Therefore, we are not designating Unit FK19 as critical habitat for the 
slabside pearlymussel at this time.

Unit FK20: French Broad River, Knox and Sevier Counties, Tennessee

    Proposed Unit FK20 includes approximately 56 rkm (35 rmi) of the 
French Broad River from its confluence with the Holston River in Knox 
County, TN, upstream to the base of Douglas Dam at rkm 51.7 (rmi 32.3) 
in Sevier County, TN. The unit is within the Tennessee River system. 
This unit is considered unoccupied by the fluted kidneyshell and 
slabside pearlymussel, but within the species' historical ranges. 
Fluted kidneyshell are only known from archaeological records in the 
French Broad River (Parmalee 1988 in Layzer and Scott 2006, pp. 481-
482). As discussed below, we consider Unit FK20 essential for the 
conservation of the fluted kidneyshell, but not the slabside 
pearlymussel, and so it is proposed as critical habitat only for the 
fluted kidneyshell. This unit is located almost entirely on private 
land, except for any small amount that is publicly owned in the form of 
bridge crossings and road easements and a small portion that is within 
Forks of the River Wildlife Management Area. The unit completely 
overlaps a nonessential experimental population for 15 mussels, 1 
snail, and 5 fishes (72 FR 52434).
    We consider this unit essential for the conservation of the fluted 
kidneyshell due to the need to re-establish the species within other 
portions of its historical range in order to reduce threats from 
stochastic events. Fluted kidneyshell are only known from 
archaeological records in the French Broad River (Parmalee 1988 in 
Layzer and Scott 2006, p. 481-482). However, between 1987 and 1995, TVA 
implemented reservoir release improvements below Douglas Dam on the 
French Broad River. These

[[Page 60838]]

improvements included the establishment of minimum flows and increasing 
the amount of dissolved oxygen in the tailwater below the reservoir 
(Scott et al. 1996, p. 11-12), improving conditions for the fluted 
kidneyshell and other aquatic species.
    The unit does currently support populations of the federally 
threatened snail darter and endangered pink mucket. In addition, other 
mussel species co-occur with these species and a diverse fish fauna, 
including hosts for the fluted kidneyshell. These host fishes are 
bottom-dwelling species that are able to move into refugia of low flows 
during high discharges from the hydropower dam upstream. Therefore, the 
fluted kidneyshell glochidia may come into contact and infest the host 
fishes. The slabside pearlymussel and its host fishes are known from 
the French Broad River drainage; however, hydropower operations make 
this habitat unsuitable for mid-water column fishes, such as the 
shiners that are hosts for the slabside pearlymussel (Layzer and Scott 
2006, pp. 481, 488-9). Therefore, we are not designating Unit FK20 as 
critical habitat for the slabside pearlymussel at this time.

Unit FK21 and SP7: Hiwassee River, Polk County, Tennessee

    Proposed Unit FK21 and SP7 includes approximately 24 rkm (15 rmi) 
of the Hiwassee River from the Highway 315 Bridge crossing upstream to 
the Highway 68 Bridge crossing in Polk County, TN. The unit is within 
the Tennessee River system and is proposed critical habitat for the 
fluted kidneyshell and slabside pearlymussel. This unit is included in 
the geographical area occupied by slabside pearlymussel at the time of 
listing. This unit is considered unoccupied by the fluted kidneyshell 
at the time of listing, but within the species' historical range. 
Fluted kidneyshell are only known from archaeological records in the 
Hiwassee River (Parmalee and Bogan 1998, p. 205). This unit is 
considered essential for the conservation of the fluted kidneyshell. A 
portion of this unit is considered a ``cut-off'' reach, because most of 
the water flow bypasses the reach through a tunnel from Apalachia Dam 
to the Apalachia powerhouse for the production of electricity. This 
unit is located entirely on federal lands within the Cherokee National 
Forest. Land and resource management decisions and activities within 
the CNF are guided by CNF's LRMP (USFS 2004b, pp. 28-37, entire).
    The channel within proposed Unit FK21 and SP7 has an abundance of 
riffle habitats (PCE 1), with relatively silt-free sand and gravel 
substrates (PCE 2). Diverse fish fauna, including fish hosts for the 
slabside pearlymussel, are known from this unit (PCE 5).
    Within this proposed unit, the slabside pearlymussel and its 
habitats may require special management considerations or protection to 
address potential adverse effects associated with silviculture-related 
activities, nonpoint source pollution, water diversion through 
Apalachia tunnel, and potential canopy loss caused by infestations of 
the hemlock wooly adelgid. Another threat to the species and their 
habitat which may require special management of the PCEs includes the 
potential for significant changes in the existing flow regime and water 
quality due to upstream impoundment As discussed in Summary of Factors 
Affecting the Species, under ``Impoundments,'' mollusk declines below 
dams are associated with changes and fluctuation in flow regime, 
scouring and erosion, reduced dissolved oxygen levels and water 
temperatures, and changes in resident fish assemblages. These 
alterations can cause mussel declines for many miles below the dam.

Unit SP8: Sequatchie River, Marion, Sequatchie, and Bledsoe Counties, 
Tennessee

    Proposed Unit SP8 includes approximately 151 rkm (94 rmi) of the 
Sequatchie River from the Highway 41, 64, 72, 2 Bridge crossing in 
Marion County, TN, upstream to the Ninemile Cross Road Bridge crossing 
in Bledsoe County, TN. The unit is within the Tennessee River system. 
This unit is included in the geographical area occupied by slabside 
pearlymussel at the time of listing. This unit is located almost 
entirely on private land, except for any small amount that is publicly 
owned in the form of bridge crossings and road easements.
    Proposed Unit SP8 has an abundance of riffle habitats (PCE 1), with 
relatively silt-free sand and gravel substrates (PCE 2), and adequate 
instream flows (PCE 3). A diverse fish fauna, including fish hosts for 
the slabside pearlymussel, are known from this unit (PCE 5).
    Within this unit, the slabside pearlymussel and its habitat may 
require special management considerations or protection to address 
potential adverse effects caused by agricultural activities, coal 
mining, silvicultural activities, lack of adequate riparian buffers, 
construction and maintenance of State and county roads, and nonpoint 
source pollution arising from a wide variety of human activities.

Unit SP9: Paint Rock River, Madison, Marshall, and Jackson Counties, 
Alabama

    Proposed Unit SP9 includes approximately 86 rkm (53 rmi) of the 
Paint Rock River from the Highway 431 Bridge crossing along the Madison 
and Marshall County line, AL, upstream to and including approximately 
11 rkm (7 rmi) of the tributary headwaters of Larkin Fork upstream to 
its confluence with Bear Creek; approximately 13 rkm (8 rmi) of Estill 
Fork upstream to its confluence with Bull Run; and approximately 16 rkm 
(10 rmi) of Hurricane Creek upstream to its confluence with Turkey 
Creek in Jackson County, AL. The unit is within the Tennessee River 
system and is proposed critical habitat for the slabside pearlymussel. 
The unit is included in the geographical area occupied by the slabside 
pearlymussel at the time of listing. Approximately 6 rkm (4 rmi) of 
this unit is federally or State-owned and adjacent to the Fern Cave 
National Wildlife Refuge and Walls of Jericho State Management Area; 
the remainder is privately owned, including a small parcel owned by the 
Alabama Land Trust. A portion of this unit (80 rkm (50 rmi)) has been 
proposed as critical habitat for the rabbitsfoot.
    The channel within proposed Unit SP9 is relatively stable, with 
excellent instream habitat (PCE 1). There is an abundance of riffle 
habitats (PCE 1), with relatively silt-free sand and gravel substrates 
(PCE 2), and adequate instream flows (PCE 3). A diverse fish fauna, 
including fish hosts for the slabside pearlymussel, are known from this 
unit (PCE 5).
    Within this proposed unit, the slabside pearlymussel and its 
habitat may require special management considerations or protection to 
address potential adverse effects associated with agricultural 
activities, silvicultural activities, off-road vehicle use and other 
recreational activities, and nonpoint source pollution originating in 
headwater reaches.

Unit FK22 and SP10: Elk River, Limestone County, Alabama, and Giles, 
Lincoln, Franklin, and Moore Counties, Tennessee

    Proposed Unit FK22 and SP10 includes approximately 164 rkm (102 
rmi) of the Elk River from its inundation at Wheeler Lake in Limestone 
County, AL, upstream to its confluence with Farris Creek at the 
dividing line between Franklin and Moore Counties, TN. The unit is 
within the Tennessee River system and is proposed critical habitat for 
the fluted kidneyshell and

[[Page 60839]]

slabside pearlymussel. This unit is included in the geographical area 
occupied by slabside pearlymussel at the time of listing. This unit is 
considered unoccupied by the fluted kidneyshell, but within the 
species' historical range. Live fluted kidneyshell have not been 
collected in the Elk River since the late-1960s (Isom et al. 1973, p. 
440). The unit is considered essential for the conservation of the 
fluted kidneyshell. This unit is located almost entirely on private 
land, except for any small amount that is publicly owned in the form of 
bridge crossings and road easements and a small portion that is within 
TVA-owned lands near Wheeler Reservoir.
    Proposed Unit FK22 and SP10 has an abundance of riffle habitats 
(PCE 1), with relatively silt-free sand and gravel substrates (PCE 2), 
and adequate instream flows (PCE 3). A diverse fish fauna, including 
fish hosts for the slabside pearlymussel, are known from this unit (PCE 
5).
    Within this proposed unit, the slabside pearlymussel and its 
habitats may require special management considerations or protection to 
address potential adverse effects associated with hydropower generation 
from Tims Ford Dam, agriculture, nonpoint source pollution, and 
instream gravel mining. Another threat to the species and their habitat 
which may require special management of the PCEs includes the potential 
for significant changes in the existing flow regime and water quality 
due to upstream impoundment. As discussed in Summary of Factors 
Affecting the Species, under ``Impoundments,'' mollusk declines below 
dams are associated with changes and fluctuation in flow regime, 
scouring and erosion, reduced dissolved oxygen levels and water 
temperatures, and changes in resident fish assemblages. These 
alterations can cause mussel declines for many miles below the dam.

Unit SP11: Bear Creek, Colbert County, Alabama, and Tishomingo County, 
Mississippi

    Proposed Unit SP11 includes approximately 42 rkm (26 rmi) of Bear 
Creek from its inundation at Pickwick Lake at rkm 37 (rmi 23) in 
Colbert County, AL, upstream through Tishomingo County, MS, and ending 
at the Mississippi/Alabama State line. The unit is within the Tennessee 
River system and is proposed critical habitat for the slabside 
pearlymussel. This unit is included in the geographical area occupied 
by the slabside pearlymussel at the time of listing. This unit is 
located almost entirely on private land, except for any small amount 
that is publicly owned in the form of bridge crossings and road 
easements, and that within Tishomingo State Park and the Natchez Trace 
Parkway. The unit completely overlaps critical habitat for the oyster 
mussel and Cumberlandian combshell (69 FR 53136; August 31, 2004) and a 
portion (42 rkm (26 rmi)) of this unit has been proposed as critical 
habitat for the rabbitsfoot (69 FR 53136).
    The channel within proposed Unit SP11 has an abundance of riffle 
habitats (PCE 1), with relatively silt-free sand and gravel substrates 
(PCE 2), and adequate instream flows (PCE 3). A diverse fish fauna, 
including fish hosts for the slabside pearlymussel, are known from this 
unit (PCE 5).
    Within this proposed unit, the slabside pearlymussel and its 
habitat may require special management considerations or protection to 
address potential adverse effects associated with releases from 
upstream impoundments, agriculture, and nonpoint source pollution 
originating in headwater reaches.

Unit FK23 and SP12: Duck River, Humphreys, Perry, Hickman, Maury, 
Marshall, and Bedford Counties, Tennessee

    Proposed Unit FK23 and SP12 includes approximately 348 rkm (216 
rmi) of the Duck River from its inundation at Kentucky Lake in 
Humphreys County, TN, upstream to its confluence with Flat Creek near 
Shelbyville in Bedford County, TN. The unit is within the Tennessee 
River system and is proposed critical habitat for the fluted 
kidneyshell and slabside pearlymussel. This unit is included in the 
geographical area occupied by both species at the time of listing. The 
fluted kidneyshell population is a result of a successful 
reintroduction program implemented by TWRA and other conservation 
partners. Approximately 64 rkm (39 rmi) of this unit is federally or 
State-owned and adjacent to the Tennessee National Wildlife Refuge, 
Natchez Trace Parkway, Yanahli Wildlife Management Area, and Henry 
Horton State Park; the remainder is privately owned. A portion of this 
unit (74 rkm (46 rmi)) has been designated as a critical habitat for 
the oyster mussel and Cumberlandian combshell (69 FR 53136) and a 
portion of this unit (234 rkm (146 rmi)) has been proposed as critical 
habitat for the rabbitsfoot.
    The channel within proposed Unit FK23 and SP12 is relatively 
stable, with excellent instream habitat (PCE 1). There is an abundance 
of riffle habitats (PCE 1), with relatively silt-free sand and gravel 
substrates (PCE 2), and adequate instream flows (PCE 3). A diverse fish 
fauna, including fish hosts for the fluted kidneyshell and slabside 
pearlymussel, are known from this unit (PCE 5).
    Within this proposed unit, the fluted kidneyshell, slabside 
pearlymussel, and their habitats may require special management 
considerations or protection to address potential adverse effects 
associated with agricultural activities (livestock), water withdrawals, 
lack of adequate riparian buffers, construction and maintenance of 
State and county roads, and nonpoint source pollution originating in 
headwater reaches.

Unit FK24 and SP13: Buffalo River, Humphreys and Perry Counties, 
Tennessee

    Proposed Unit FK24 and SP13 includes approximately 50 rkm (31 rmi) 
of the Buffalo River from its confluence with the Duck River in 
Humphreys County, TN, upstream to its confluence with Cane Creek in 
Perry County, TN. The unit is within the Tennessee River system and is 
proposed critical habitat for the fluted kidneyshell and slabside 
pearlymussel. This unit is included in the geographical area occupied 
by slabside pearlymussel at the time of listing. This unit is 
considered unoccupied by the fluted kidneyshell, but within the 
species' historical range. Live fluted kidneyshell have not been 
collected in the Buffalo River since the early 1920s (Ortmann 1924, p. 
28). The unit is considered essential for the conservation of the 
fluted kidneyshell. This unit is located almost entirely on private 
land, except for any small amount that is publicly owned in the form of 
bridge crossings and road easements.
    The channel within proposed Unit FK24 and SP13 is relatively 
stable, with excellent instream habitat (PCE 1). There is an abundance 
of riffle habitats (PCE 1), with relatively silt-free sand and gravel 
substrates (PCE 2), and adequate instream flows (PCE 3). A diverse fish 
fauna, including fish hosts for the slabside pearlymussel, are known 
from this unit (PCE 5).
    Within this proposed unit, the slabside pearlymussel and its 
habitats may require special management considerations or protection to 
address potential adverse effects associated with agriculture and 
nonpoint source pollution.

Effects of Critical Habitat Designation

Section 7 Consultation

    Section 7(a)(2) of the Act requires Federal agencies, including the 
Service, to ensure that any action they fund,

[[Page 60840]]

authorize, or carry out is not likely to jeopardize the continued 
existence of any endangered species or threatened species or result in 
the destruction or adverse modification of designated critical habitat 
of such species. In addition, section 7(a)(4) of the Act requires 
Federal agencies to confer with the Service on any agency 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 proposed critical habitat.
    Decisions by the 5th and 9th Circuit Courts of Appeal have 
invalidated our regulatory definition of ``destruction or adverse 
modification'' (50 CFR 402.02) (see Gifford Pinchot Task Force v. U.S. 
Fish and Wildlife Service, 378 F. 3d 1059 (9th Cir. 2004) and Sierra 
Club v. U.S. Fish and Wildlife Service, 245 F.3d 434, 442 (5th Cir. 
2001)), and we do not rely on this regulatory definition when analyzing 
whether an action is likely to destroy or adversely modify critical 
habitat. Under the provisions of the Act, we determine destruction or 
adverse modification on the basis of whether, with implementation of 
the proposed Federal action, the affected critical habitat would 
continue to serve its intended conservation role for the species.
    If a Federal action may affect a listed species or its critical 
habitat, the responsible Federal agency (action agency) must enter into 
consultation with us. Examples of actions that are subject to the 
section 7 consultation process are 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 CWA 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 the Federal 
Emergency Management Agency). Federal actions not affecting listed 
species or critical habitat, and actions on State, tribal, local, or 
private lands that are not federally funded or authorized, do not 
require section 7 consultation.
    As a result of section 7 consultation, we document compliance with 
the requirements of section 7(a)(2) through our issuance of:
    (1) A concurrence letter for Federal actions that may affect, but 
are not likely to adversely affect, listed species or critical habitat; 
or
    (2) A biological opinion for Federal actions that may affect, or 
are likely to adversely affect, listed species or critical habitat.
    When we issue a biological opinion concluding that a project is 
likely to jeopardize the continued existence of a listed species and/or 
destroy or adversely modify critical habitat, we provide reasonable and 
prudent alternatives to the project, if any are identifiable, that 
would avoid the likelihood of jeopardy and/or destruction or adverse 
modification of critical habitat. We define ``reasonable and prudent 
alternatives'' (at 50 CFR 402.02) as alternative actions identified 
during consultation that:
    (1) Can be implemented in a manner consistent with the intended 
purpose of the action;
    (2) Can be implemented consistent with the scope of the Federal 
agency's legal authority and jurisdiction;
    (3) Are economically and technologically feasible; and
    (4) Would, in the Director's opinion, avoid the likelihood of 
jeopardizing the continued existence of the listed species and/or avoid 
the likelihood of destroying or adversely modifying critical habitat.
    Reasonable and prudent alternatives can vary from slight project 
modifications to extensive redesign or relocation of the project. Costs 
associated with implementing a reasonable and prudent alternative are 
similarly variable.
    Regulations at 50 CFR 402.16 require Federal agencies to reinitiate 
consultation on previously reviewed actions in instances where we have 
listed a new species or subsequently designated critical habitat that 
may be affected and the Federal agency has retained discretionary 
involvement or control over the action (or the agency's discretionary 
involvement or control is authorized by law). Consequently, Federal 
agencies sometimes may need to request reinitiation of consultation 
with us on actions for which formal consultation has been completed, if 
those actions with discretionary involvement or control may affect 
subsequently listed species or designated critical habitat.

Application of the ``Adverse Modification'' Standard

    The key factor related to the adverse modification determination is 
whether, with implementation of the proposed Federal action, the 
affected critical habitat would continue to serve its intended 
conservation role for the species. Activities that may destroy or 
adversely modify critical habitat are those that alter the PBFs to an 
extent that appreciably reduces the conservation value of critical 
habitat for fluted kidneyshell or slabside pearlymussel. As discussed 
above, the role of critical habitat is to support life-history needs 
and provide for the conservation of these species.
    Section 4(b)(8) of the Act requires us to briefly evaluate and 
describe, in any proposed or final regulation that designates critical 
habitat, activities involving a Federal action that may destroy or 
adversely modify such habitat, or that may be affected by such 
designation.
    Activities that may affect critical habitat, when carried out, 
funded, or authorized by a Federal agency, should result in 
consultation for the fluted kidneyshell or slabside pearlymussel. These 
activities include, but are not limited to:
    (1) Actions that would alter the geomorphology of their stream and 
river habitats. Such activities could include, but are not limited to, 
instream excavation or dredging, impoundment, channelization, sand and 
gravel mining, clearing riparian vegetation, and discharge of fill 
materials. These activities could cause aggradation or degradation of 
the channel bed elevation or significant bank erosion and result in 
entrainment or burial of these mussels, and could cause other direct or 
cumulative adverse effects to these species and their life cycles.
    (2) Actions that would significantly alter the existing flow regime 
where these species occur. Such activities could include, but are not 
limited to; impoundment, urban development, water diversion, water 
withdrawal, water draw-down, and hydropower generation. These 
activities could eliminate or reduce the habitat necessary for growth 
and reproduction of these mussels and their fish hosts.
    (3) Actions that would significantly alter water chemistry or water 
quality (for example, temperature, pH, contaminants, and excess 
nutrients). Such activities could include, but are not limited to, 
hydropower discharges, or the release of chemicals, biological 
pollutants, or heated effluents into surface water or connected 
groundwater at a point source or by dispersed release (nonpoint 
source). These activities could alter water conditions that are beyond 
the tolerances of these mussels and their fish hosts or both, and 
result in direct or cumulative adverse effects to the species 
throughout their life cycles.
    (4) Actions that would significantly alter stream bed material 
composition and quality by increasing sediment deposition or 
filamentous algal growth. Such activities could include, but are not 
limited to, construction projects, gravel and sand mining, oil and gas

[[Page 60841]]

development, coal mining, livestock grazing, timber harvest, and other 
watershed and floodplain disturbances that release sediments or 
nutrients into the water. These activities could eliminate or reduce 
habitats necessary for the growth and reproduction of these mussels or 
their fish hosts or both, by causing excessive sedimentation and burial 
of the species or their habitats, or nutrification leading to excessive 
filamentous algal growth. Excessive filamentous algal growth can cause 
reduced nighttime dissolved oxygen levels through respiration, and 
prevent juvenile mussels from settling into stream sediments.

Exemptions

Application of Section 4(a)(3) of the Act

    The Sikes Act Improvement Act of 1997 (Sikes Act) (16 U.S.C. 670a) 
required each military installation that includes land and water 
suitable for the conservation and management of natural resources to 
complete an integrated natural resources management plan (INRMP) by 
November 17, 2001. An INRMP integrates implementation of the military 
mission of the installation with stewardship of the natural resources 
found on the base. Each INRMP includes:
    (1) An assessment of the ecological needs on the installation, 
including the need to provide for the conservation of listed species;
    (2) A statement of goals and priorities;
    (3) A detailed description of management actions to be implemented 
to provide for these ecological needs; and
    (4) A monitoring and adaptive management plan.
    Among other things, each INRMP must, to the extent appropriate and 
applicable, provide for fish and wildlife management; fish and wildlife 
habitat enhancement or modification; wetland protection, enhancement, 
and restoration where necessary to support fish and wildlife; and 
enforcement of applicable natural resource laws.
    The National Defense Authorization Act for Fiscal Year 2004 (Pub. 
L. 108-136) amended the Act to limit areas eligible for designation as 
critical habitat. Specifically, section 4(a)(3)(B)(i) of the Act (16 
U.S.C. 1533(a)(3)(B)(i)) now provides: ``The Secretary shall not 
designate as critical habitat any lands or other geographical areas 
owned or controlled by the Department of Defense, or designated for its 
use, that are subject to an integrated natural resources management 
plan prepared under section 101 of the Sikes Act (16 U.S.C. 670a), if 
the Secretary determines in writing that such plan provides a benefit 
to the species for which critical habitat is proposed for 
designation.''
    There are no Department of Defense lands with a completed INRMP 
within the proposed critical habitat designation.

Exclusions

Application of Section 4(b)(2) of the Act

    Section 4(b)(2) of the Act states that the Secretary shall 
designate and make revisions to critical habitat on the basis of the 
best available scientific data after taking into consideration the 
economic impact, national security impact, and any other relevant 
impact of specifying any particular area as critical habitat. The 
Secretary may exclude an area from critical habitat if he determines 
that the benefits of such exclusion outweigh the benefits of specifying 
such area as part of the critical habitat, unless he determines, based 
on the best scientific data available, that the failure to designate 
such area as critical habitat will result in the extinction of the 
species. In making that determination, the statute on its face, as well 
as the legislative history, are clear that the Secretary has broad 
discretion regarding which factor(s) to use and how much weight to give 
to any factor.
    Under section 4(b)(2) of the Act, we may exclude an area from 
designated critical habitat based on economic impacts, impacts on 
national security, or any other relevant impacts. In considering 
whether to exclude a particular area from the designation, we identify 
the benefits of including the area in the designation, identify the 
benefits of excluding the area from the designation, and evaluate 
whether the benefits of exclusion outweigh the benefits of inclusion. 
If the analysis indicates that the benefits of exclusion outweigh the 
benefits of inclusion, the Secretary may exercise his discretion to 
exclude the area only if such exclusion would not result in the 
extinction of the species.
Economic Impacts
    Under section 4(b)(2) of the Act, we consider the economic impacts 
of specifying any particular area as critical habitat. In order to 
consider economic impacts, we are preparing an analysis of the economic 
impacts of the proposed critical habitat designation and related 
factors.
    We will announce the availability of the draft economic analysis as 
soon as it is completed. At that time, copies of the draft economic 
analysis will be available for downloading from the Internet at https://www.regulations.gov, or by contacting the Tennessee Ecological Services 
Field Office directly (see FOR FURTHER INFORMATION CONTACT). During the 
development of a final designation, we will consider economic impacts, 
public comments, and other new information, and areas may be excluded 
from the final critical habitat designation under section 4(b)(2) of 
the Act and our implementing regulations at 50 CFR 424.19.
National Security Impacts
    Under section 4(b)(2) of the Act, we consider whether there are 
lands owned or managed by the Department of Defense where a national 
security impact might exist. In preparing this proposal, we have 
determined that the lands within the proposed designation of critical 
habitat for the fluted kidneyshell and slabside pearlymussel are not 
owned or managed by the Department of Defense, and, therefore, we 
anticipate no impact on national security.
Other Relevant Impacts
    Under section 4(b)(2) of the Act, we consider any other relevant 
impacts, in addition to economic impacts and impacts on national 
security. We consider a number of factors, including whether the 
landowners have developed any HCPs or other management plans for the 
area, or whether there are conservation partnerships that would be 
encouraged by designation of, or exclusion from, critical habitat. In 
addition, we look at any tribal issues, and consider the government-to-
government relationship of the United States with tribal entities. We 
also consider any social impacts that might occur because of the 
designation.
    In preparing this proposal, we have determined that there are 
currently no HCPs or other management plans for the fluted kidneyshell 
or slabside pearlymussel, and the proposed designation does not include 
any tribal lands or trust resources. Therefore, we anticipate no impact 
on tribal lands or HCPs from this proposed critical habitat 
designation.

Nonessential Experimental Populations

    Congress made significant changes to the Act, with the addition of 
section 10(j) in 1982, which provides for the designation of specific 
reintroduced populations of listed species as ``experimental 
populations.'' This section was designed to provide us with an 
innovative means to introduce a listed species into unoccupied habitat 
within its historical range when doing so would foster the conservation 
and

[[Page 60842]]

recovery of the species. Experimental populations provide us with a 
flexible, proactive means to meet recovery criteria while not 
alienating stakeholders, such as other agencies, municipalities, and 
landowners, whose cooperation is essential for eventual success of the 
reintroduced population.
    Section 10(j) increases our flexibility in managing an experimental 
population by allowing us to treat a population as a threatened 
species, regardless of the species' status elsewhere in its range. 
Threatened species status gives us more discretion in developing and 
implementing management programs and special regulations for a 
population and allows us to develop any regulations we consider 
necessary and advisable to provide for the conservation of a threatened 
species under Section 4(d) of the Act. This flexibility allows us to 
manage the experimental population in a manner that will ensure that 
current and future land, water, or air uses and activities will not be 
unnecessarily restricted and the population can be managed for recovery 
purposes.
    When we designate a population as experimental, section 10(j) of 
the Act requires that we determine whether that population is either 
essential or nonessential to the continued existence of the species, on 
the basis of the best available information. Nonessential experimental 
populations (NEPs) located outside the National Wildlife Refuge System 
or National Park System lands are treated, for the purposes of section 
7 of the Act, as if they are proposed for listing as a threatened 
species, while on National Wildlife Refuges or National Parks the 
species is treated as a threatened species. Section 7(a)(2) of the Act, 
which requires Federal agencies to ensure that their activities are not 
likely to jeopardize the continued existence of a listed species, would 
not apply except on National Wildlife Refuge System and National Park 
System lands. Experimental populations determined to be ``essential'' 
to the survival of the species would remain subject to the consultation 
provisions of section 7(a)(2) of the Act.
    As mentioned earlier in the unit descriptions and referenced in 
Table 5, there are two nonessential experimental populations (NEPs) for 
listed aquatic species that overlap with the proposed critical habitat 
designation. These include the NEP for the yellowfin madtom in the 
North Fork of the Holston River (53 FR 29335), which overlaps with Unit 
FK12 and SP1, and the NEP for 21 listed aquatic species (including the 
yellowfin madtom) in the lower French Broad and Holston Rivers (72 FR 
52434), which overlaps with Units FK19 and FK20. These NEPs were not 
established specifically for the conservation of the fluted kidneyshell 
or slabside pearlymussel, which were candidate species when the NEPs 
were published, but rather to promote the reintroduction of their 
target listed species into historical habitat. They were developed with 
the support of numerous partners, including the Tennessee Wildlife 
Resources Agency, Tennessee Valley Authority, Virginia Department of 
Game and Inland Fisheries, and others. We would need to amend the NEPs 
through the rulemaking process in order for the fluted kidneyshell and 
slabside pearlymussel to be included.
    The North Fork of the Holston River is considered occupied by both 
the slabside pearlymussel and the fluted kidneyshell, and presently 
contains numerous PCEs (see ``Proposed Critical Habitat Designation'') 
and is therefore being proposed as critical habitat. The lower Holston 
River (below Cherokee Dam) and French Broad River (below Douglas Dam) 
are being proposed as unoccupied habitat for the fluted kidneyshell 
because we have determined these river reaches are essential to the 
conservation of the species.
    Accordingly, at this time the Secretary does not propose to exert 
his discretion to exclude any areas from the final designation based on 
other relevant impacts. However, we recognize that exclusion of river 
reaches covered by these NEPs from critical habitat may continue to 
encourage conservation and reintroduction efforts for numerous 
imperiled aquatic species in the upper Tennessee River Basin. 
Therefore, we are requesting information on whether the benefits of the 
exclusion of river reaches covered by these NEPs would outweigh the 
benefits of inclusion under section 4(b)(2) of the Act. Based on 
information received during the comment period, the Secretary may 
reconsider exclusion in the final rule.

Peer Review

    In accordance with our joint policy on peer review published in the 
Federal Register on July 1, 1994 (59 FR 34270), we will seek the expert 
opinions of at least three appropriate and independent specialists 
regarding this proposed rule. The purpose of peer review is to ensure 
that our proposed listing determination and critical habitat 
designation are based on scientifically sound data, assumptions, and 
analyses. We have invited these peer reviewers to comment during this 
public comment period on this proposed rule.
    We will consider all comments and information received during this 
comment period on this proposed rule during our preparation of a final 
determination. Accordingly, the final decision may differ from this 
proposal.

Public Hearings

    Section 4(b)(5) of the Act provides for one or more public hearings 
on this proposal, if requested. Requests must be received within 45 
days after the date of publication of this proposed rule in the Federal 
Register. Such requests must be sent to the address shown in the FOR 
FURTHER INFORMATION CONTACT section. We will schedule public hearings 
on this proposal, if any are requested, and announce the dates, times, 
and places of those hearings, as well as how to obtain reasonable 
accommodations, in the Federal Register and local newspapers at least 
15 days before the hearing.

Required Determinations

Regulatory Planning and Review (Executive Orders 12866 and 13563)

    Executive Order 12866 provides that the Office of Information and 
Regulatory Affairs (OIRA) will review all significant rules. The Office 
of Information and Regulatory Affairs has determined that this rule is 
not significant.
    Executive Order 13563 reaffirms the principles of E.O. 12866 while 
calling for improvements in the nation's regulatory system to promote 
predictability, to reduce uncertainty, and to use the best, most 
innovative, and least burdensome tools for achieving regulatory ends. 
The executive order directs agencies to consider regulatory approaches 
that reduce burdens and maintain flexibility and freedom of choice for 
the public where these approaches are relevant, feasible, and 
consistent with regulatory objectives. E.O. 13563 emphasizes further 
that regulations must be based on the best available science and that 
the rulemaking process must allow for public participation and an open 
exchange of ideas. We have developed this rule in a manner consistent 
with these requirements.

Regulatory Flexibility Act

    Under the Regulatory Flexibility Act (RFA; 5 U.S.C. 601 et seq.) as 
amended by the Small Business Regulatory Enforcement Fairness Act of 
1996 (SBREFA; 5 U.S.C. 801 et seq.), whenever an agency is required to 
publish a notice of rulemaking for any proposed or final rule, it must 
prepare and make available for public comment

[[Page 60843]]

a regulatory flexibility analysis that describes the effects of the 
rule on small entities (small businesses, small organizations, and 
small government jurisdictions). However, no regulatory flexibility 
analysis is required if the head of the agency certifies the rule will 
not have a significant economic impact on a substantial number of small 
entities. The SBREFA amended the RFA to require Federal agencies to 
provide a certification statement of the factual basis for certifying 
that the rule will not have a significant economic impact on a 
substantial number of small entities.
    According to the Small Business Administration, small entities 
include small organizations such as independent nonprofit 
organizations; small governmental jurisdictions, including school 
boards and city and town governments that serve fewer than 50,000 
residents; and small businesses (13 CFR 121.201). Small businesses 
include such businesses as manufacturing and mining concerns with fewer 
than 500 employees, wholesale trade entities with fewer than 100 
employees, retail and service businesses with less than $5 million in 
annual sales, general and heavy construction businesses with less than 
$27.5 million in annual business, special trade contractors doing less 
than $11.5 million in annual business, and forestry and logging 
operations with fewer than 500 employees and annual business less than 
$7 million. To determine whether small entities may be affected, we 
will consider the types of activities that might trigger regulatory 
impacts under this designation as well as types of project 
modifications that may result. In general, the term ``significant 
economic impact'' is meant to apply to a typical small business firm's 
business operations.
    Importantly, the incremental impacts of a rule must be both 
significant and substantial to prevent certification of the rule under 
the RFA and to require the preparation of an initial regulatory 
flexibility analysis. If a substantial number of small entities are 
affected by the proposed critical habitat designation, but the per-
entity economic impact is not significant, the Service may certify. 
Likewise, if the per-entity economic impact is likely to be 
significant, but the number of affected entities is not substantial, 
the Service may also certify.
    Under the RFA, as amended, and following recent court decisions, 
Federal agencies are only required to evaluate the potential 
incremental impacts of rulemaking on those entities directly regulated 
by the rulemaking itself, and not the potential impacts to indirectly 
affected entities. The regulatory mechanism through which critical 
habitat protections are realized is section 7 of the Act, which 
requires Federal agencies, in consultation with the Service, to ensure 
that any action authorized, funded, or carried by the Agency is not 
likely to adversely modify critical habitat. Therefore, only Federal 
action agencies are directly subject to the specific regulatory 
requirement (avoiding destruction and adverse modification) imposed by 
critical habitat designation. Under these circumstances, it is our 
position that only Federal action agencies will be directly regulated 
by this designation. Therefore, because Federal agencies are not small 
entities, the Service may certify that the proposed critical habitat 
rule will not have a significant economic impact on a substantial 
number of small entities.
    We acknowledge, however, that in some cases, third-party proponents 
of the action subject to permitting or funding may participate in a 
section 7 consultation, and thus may be indirectly affected. We believe 
it is good policy to assess these impacts if we have sufficient data 
before us to complete the necessary analysis, whether or not this 
analysis is strictly required by the RFA. While this regulation does 
not directly regulate these entities, in our draft economic analysis we 
will conduct a brief evaluation of the potential number of third 
parties participating in consultations on an annual basis in order to 
ensure a more complete examination of the incremental effects of this 
proposed rule in the context of the RFA.
    In conclusion, we believe that, based on our interpretation of 
directly regulated entities under the RFA and relevant case law, this 
designation of critical habitat will only directly regulate Federal 
agencies, which are not by definition small business entities. As such, 
certify that, if promulgated, this designation of critical habitat 
would not have a significant economic impact on a substantial number of 
small business entities. Therefore, an initial regulatory flexibility 
analysis is not required. However, although not necessarily required by 
the RFA, in our draft economic analysis for this proposal we will 
consider and evaluate the potential effects to third parties that may 
be involved with consultations with Federal action agencies related to 
this action.

Energy Supply, Distribution, or Use--Executive Order 13211

    Executive Order 13211 (Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use) requires 
agencies to prepare Statements of Energy Effects when undertaking 
certain actions. We do not expect the designation of this proposed 
critical habitat designation to significantly affect energy supplies, 
distribution, or use. Natural gas and oil exploration and development 
activities occur or could potentially occur in all proposed critical 
habitat units. However, compliance with State regulatory requirements 
or voluntary best management practices would be expected to minimize 
impacts of natural gas and oil exploration and development in the areas 
of proposed critical habitat for both species. The measures for natural 
gas and oil exploration and development are generally not considered a 
substantial cost compared with overall project costs and are already 
being implemented by oil and gas companies.
    Coal mining occurs or could potentially occur in proposed critical 
habitat units in Kentucky, Tennessee, and Virginia, and was identified 
as an activity that may have adverse effects on these species and their 
habitat. Incidental take for listed species associated with surface 
coal mining activities is currently covered under a programmatic, non-
jeopardy biological opinion between the Office of Surface Mining and 
the Service, completed in 1996 (Service 1996, entire). The biological 
opinion covers existing, proposed, and future endangered and threatened 
species that may be affected by the implementation and administration 
of surface coal mining programs under the Surface Mining Control and 
Reclamation Act of 1977 (30 U.S.C. 1201 et seq.). Through its analysis, 
the Service concluded that the proposed action (surface coal mining and 
reclamation activities) was not likely to jeopardize the continued 
existence of any threatened, endangered, or proposed species or result 
in adverse modification of designated or proposed critical habitat. 
Based on this conclusion, we do not anticipate that the designation of 
critical habitat would constitute a significant energy action, and have 
therefore not completed a Statement of Energy Effects. However, we will 
further evaluate this issue as we conduct our economic analysis, and 
review and revise this assessment as warranted.
    Hydropower generation occurs upstream of proposed critical habitat 
units in the mainstem Holston, French Broad, Hiwassee, and Elk Rivers. 
Incidental take for listed species (which does not include the fluted 
kidneyshell and slabside pearlymussel), associated

[[Page 60844]]

with hydropower generation, is currently covered under two 
programmatic, non-jeopardy biological opinions between the Tennessee 
Valley Authority (TVA) and the Service, completed in 2004 and 2006 
(Service, 2004, entire; Service 2006, entire). These biological 
opinions cover TVA's routine operations and maintenance of water 
control structures in the Tennessee River System and species that were 
listed at that time. The Service concluded that the proposed action 
(operation and maintenance activities at TVA dams--including hydropower 
generation) was not likely to jeopardize continued existence of any 
listed species. Based on our experience with the currently listed 
species and their critical habitat, we do not anticipate this action 
will qualify as a significant energy action, and therefore we have not 
prepared a Statement of Energy Effects at this time. However, we will 
further evaluate this issue as we conduct our economic analysis, and 
review and revise this assessment as warranted.

Unfunded Mandates Reform Act

    In accordance with the Unfunded Mandates Reform Act (2 U.S.C. 1501 
et seq.), we make the following findings:
    (1) This rule would not produce a Federal mandate. In general, a 
Federal mandate is a provision in legislation, statute, or regulation 
that would impose an enforceable duty upon State, local, or tribal 
governments, or the private sector, and includes both ``Federal 
intergovernmental mandates'' and ``Federal private sector mandates.'' 
These terms are defined in 2 U.S.C. 658(5)-(7). ``Federal 
intergovernmental mandate'' includes a regulation that ``would impose 
an enforceable duty upon State, local, or [T]ribal governments'' with 
two exceptions. It excludes ``a condition of Federal assistance.'' It 
also excludes ``a duty arising from participation in a voluntary 
Federal program,'' unless the regulation ``relates to a then-existing 
Federal program under which $500,000,000 or more is provided annually 
to State, local, and [T]ribal governments under entitlement 
authority,'' if the provision would ``increase the stringency of 
conditions of assistance'' or ``place caps upon, or otherwise decrease, 
the Federal Government's responsibility to provide funding,'' and the 
State, local, or tribal governments ``lack authority'' to adjust 
accordingly. At the time of enactment, these entitlement programs were: 
Medicaid; AFDC work programs; Child Nutrition; Food Stamps; Social 
Services Block Grants; Vocational Rehabilitation State Grants; Foster 
Care, Adoption Assistance, and Independent Living; Family Support 
Welfare Services; and Child Support Enforcement. ``Federal private 
sector mandate'' includes a regulation that ``would impose an 
enforceable duty upon the private sector, except (i) a condition of 
Federal assistance or (ii) a duty arising from participation in a 
voluntary Federal program.''
    The designation of critical habitat does not impose a legally 
binding duty on non-Federal entities or private parties. Under the Act, 
the only regulatory effect is that Federal agencies must ensure that 
their actions do not destroy or adversely modify critical habitat under 
section 7 of the Act. While non-Federal entities that receive Federal 
funding, assistance, or permits, or that otherwise require approval or 
authorization from a Federal agency for an action, may be indirectly 
impacted by the designation of critical habitat, the legally binding 
duty to avoid destruction or adverse modification of critical habitat 
rests squarely on the Federal agency. Furthermore, to the extent that 
non-Federal entities are indirectly impacted because they receive 
Federal assistance or participate in a voluntary Federal aid program, 
the Unfunded Mandates Reform Act would not apply, nor would critical 
habitat shift the costs of the large entitlement programs listed above 
onto State governments.
    (2) We do not believe that the proposed designation of critical 
habitat for the fluted kidneyshell or slabside pearlymussel would 
significantly or uniquely affect small governments because these mussel 
species occur primarily in State-owned river channels, or in remote 
privately owned stream channels. As such, a Small Government Agency 
Plan is not required. We will, however, further evaluate this issue as 
we conduct our economic analysis and revise this assessment if 
appropriate.

Takings--Executive Order 12630

    In accordance with Executive Order 12630 (Government Actions and 
Interference with Constitutionally Protected Private Property Rights), 
we have analyzed the potential takings implications of designating 
critical habitat for the fluted kidneyshell and slabside pearlymussel 
in a takings implications assessment. Critical habitat designation does 
not affect landowner actions that do not require Federal funding or 
permits, nor does it preclude development of habitat conservation 
programs or issuance of incidental take permits to permit actions that 
do require Federal funding or permits to go forward. The takings 
implications assessment concludes that this designation of critical 
habitat for these species does not pose significant takings 
implications for lands within or affected by the designation.

Federalism--Executive Order 13132

    In accordance with Executive Order 13132 (Federalism), this 
proposed rule does not have significant Federalism effects. A 
federalism summary impact statement is not required. In keeping with 
Department of the Interior and Department of Commerce policy, we 
requested information from, and coordinated development of, this 
proposed critical habitat designation with appropriate State resource 
agencies in Alabama, Kentucky, Mississippi, Tennessee, and Virginia. 
The designation may have some benefit to these governments because the 
areas that contain the PBFs essential to the conservation of the 
species are more clearly defined, and the features of the habitat 
necessary to the conservation of the species are specifically 
identified. This information does not alter where and what federally 
sponsored activities may occur. However, it may assist local 
governments in long-range planning (rather than having them wait for 
case-by-case section 7 consultations to occur).
    Where State and local governments require approval or authorization 
from a Federal agency for actions that may affect critical habitat, 
consultation under section 7(a)(2) would be required. While non-Federal 
entities that receive Federal funding, assistance, or permits, or that 
otherwise require approval or authorization from a Federal agency for 
an action, may be indirectly impacted by the designation of critical 
habitat, the legally binding duty to avoid destruction or adverse 
modification of critical habitat rests squarely on the Federal agency.

Civil Justice Reform--Executive Order 12988

    In accordance with Executive Order 12988 (Civil Justice Reform), 
the Office of the Solicitor has determined that the rule does not 
unduly burden the judicial system and that it meets the requirements of 
sections 3(a) and 3(b)(2) of the Order. We have proposed designating 
critical habitat in accordance with the provisions of the Act. This 
proposed rule uses standard property descriptions and identifies the 
PBFs within the designated areas to assist the public in understanding 
the habitat needs of the fluted kidneyshell and slabside pearlymussel.

[[Page 60845]]

Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.)

    This rule does not contain any new collections of information that 
require approval by OMB under the Paperwork Reduction Act of 1995 (44 
U.S.C. 3501 et seq.). This rule will not impose recordkeeping or 
reporting requirements on State or local governments, individuals, 
businesses, or organizations. An agency may not conduct or sponsor, and 
a person is not required to respond to, a collection of information 
unless it displays a currently valid OMB control number.

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

    We have determined that environmental assessments and environmental 
impact statements, as defined under the authority of the National 
Environmental Policy Act (NEPA; 42 U.S.C. 4321 et seq.), need not be 
prepared in connection with listing a species as endangered or 
threatened under the Endangered Species Act. We published a notice 
outlining our reasons for this determination in the Federal Register on 
October 25, 1983 (48 FR 49244).
    It is our position that, outside the jurisdiction of the U.S. Court 
of Appeals for the Tenth Circuit, we do not need to prepare 
environmental analyses as defined by NEPA in connection with listing a 
species or designating critical habitat under the Act. We published a 
notice outlining our reasons for this determination in the Federal 
Register on October 25, 1983 (48 FR 49244). This position was upheld by 
the U.S. Court of Appeals for the Ninth Circuit (Douglas County v. 
Babbitt, 48 F.3d 1495 (9th Cir. 1995), cert. denied 516 U.S. 1042 
(1996)).

Clarity of the Rule

    We are required by Executive Orders 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:
    (a) Be logically organized;
    (b) Use the active voice to address readers directly;
    (c) Use clear language rather than jargon;
    (d) Be divided into short sections and sentences; and
    (e) 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 the ADDRESSES section. To 
better help us revise the rule, your comments should be as specific as 
possible. For example, you should tell us the numbers of the sections 
or paragraphs that are unclearly written, which sections or sentences 
are too long, the sections where you feel lists or tables would be 
useful, etc.

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994, 
Government-to-Government Relations with Native American Tribal 
Governments (59 FR 22951), E.O. 13175, 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 
Secretarial Order 3206 of June 5, 1997 (American Indian Tribal Rights, 
Federal-Tribal Trust Responsibilities, and the Endangered Species Act), 
we readily acknowledge our responsibilities to work directly with 
Tribes in developing programs for healthy ecosystems, to acknowledge 
that tribal lands are not subject to the same controls as Federal 
public lands, to remain sensitive to Indian culture, and to make 
information available to Tribes.
    We have determined that there are no Tribal lands currently 
occupied by the species that contain the features essential for the 
conservation of, and no Tribal lands that are essential for the 
conservation of, these two species. Therefore, we have not proposed 
designation of critical habitat for these species on Tribal lands.

References Cited

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

Authors

    The primary authors of this package are the staff members of the 
Tennessee Ecological Services Field Office.

List of Subjects in 50 CFR Part 17

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

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

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

    Authority:  16 U.S.C. 1361-1407; 16 U.S.C. 1531-1544; 16 U.S.C. 
4201-4245; Pub. L. 99-625, 100 Stat. 3500; unless otherwise noted.

    2. Amend Sec.  17.11(h) by adding entries for ``Kidneyshell, 
fluted'' and ``Pearlymussel, slabside'' in alphabetical order under 
``CLAMS'' to the List of Endangered and Threatened Wildlife to read as 
follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
                          Species                                                    Vertebrate
------------------------------------------------------------                         population
                                                                                       where                                      Critical     Special
                                                                 Historic range      endangered       Status       When listed    habitat       rules
            Common name                  Scientific name                                 or
                                                                                     threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
Clams
 
                                                                      * * * * * * *
Kidneyshell, fluted................  Ptychobranchus          U.S.A. (AL, KY, TN,             NA  E                 ...........     17.95(f)           NA
                                      subtentum.              VA).
 
                                                                      * * * * * * *
Pearlymussel, slabside.............  Pleuronaia              U.S.A. (AL, KY, MS,             NA  E                 ...........     17.95(f)           NA
                                      dolabelloides.          TN, VA).
 

[[Page 60846]]

 
                                                                      * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------

    3. In Sec.  17.95, amend paragraph (f) by adding entries for 
``Fluted Kidneyshell (Ptychobranchus subtentum)'' and ``Slabside 
Pearlymussel (Pleuronaia dolabelloides)'' in that order immediately 
following the entry for Altamaha spinymussel (Elliptio spinosa), to 
read as follows:


Sec.  17.95  Critical habitat--fish and wildlife.

* * * * *
    (f) Clams and Snails.
* * * * *
Fluted Kidneyshell (Ptychobranchus subtentum)
    (1) Critical habitat units are depicted on the maps below for 
Limestone County, Alabama; Jackson, Laurel, McCreary, Pulaski, 
Rockcastle, and Wayne Counties, Kentucky; Bedford, Claiborne, Cocke, 
Fentress, Franklin, Giles, Grainger, Greene, Hamblen, Hancock, Hickman, 
Humphreys, Jefferson, Knox, Lincoln, Marshall, Maury, Moore, Morgan, 
Overton, Perry, Pickett, Polk, Scott, and Sevier Counties, Tennessee; 
and Bland, Lee, Russell, Scott, Smyth, Tazewell, Washington, and Wythe 
Counties, Virginia.
    (2) Within these areas, the primary constituent elements of the 
physical or biological features essential to the conservation of fluted 
kidneyshell consist of five components:
    (i) Riffle habitats within large, geomorphically stable stream 
channels (channels that maintain lateral dimensions, longitudinal 
profiles, and sinuosity patterns over time without an aggrading or 
degrading bed elevation).
    (ii) Stable substrates of sand, gravel, and cobble with low to 
moderate amounts of fine sediment and containing flow refugia with low 
shear stress.
    (iii) A natural hydrologic flow regime (magnitude, frequency, 
duration, and seasonality of discharge over time) necessary to maintain 
benthic habitats where the species are found, and connectivity of 
rivers with the floodplain, allowing the exchange of nutrients and 
sediment for habitat maintenance, food availability for all life 
stages, and spawning habitat for native fishes.
    (iv) Water quality with low levels of pollutants and including a 
natural temperature regime, pH (between 6.0 to 8.5), oxygen content 
(not less than 5.0 milligrams/liter), hardness, and turbidity necessary 
for normal behavior, growth, and viability of all life stages.
    (v) The presence of abundant fish hosts necessary for recruitment 
of the fluted kidneyshell.
    (3) Critical habitat does not include manmade structures (such as 
buildings, aqueducts, dams, roads, and other paved areas) and the land 
on which they are located existing within the legal boundaries on the 
effective date of this rule.
    (4) Critical habitat map units. Data layers defining map units were 
created with USGS National Hydrography Dataset (NHD\+\) GIS data. The 
1:100,000 river reach (route) files were used to calculate river 
kilometers and miles. ESRIs ArcGIS 10.0 software was used to determine 
longitude and latitude coordinates using decimal degrees. The 
projection used in mapping all units was USA Contiguous Albers Equal 
Area Conic USGS version, NAD 83, meters. The following data sources 
were referenced to identify features (like roads and streams) used to 
delineate the upstream and downstream extents of critical habitat 
units: NHD\+\ flowline and waterbody data, 2011 Navteq roads data, USA 
Topo ESRI online basemap service, DeLorme Atlas and Gazetteers, and 
USGS 7.5 minute topographic maps. The maps in this entry, as modified 
by any accompanying regulatory text, establish the boundaries of the 
critical habitat designation. The coordinates or plot points or both on 
which each map is based are available to the public at the field office 
Internet site (https://www.fws.gov/cookeville), https://www.regulations.gov at Docket No. FWS-R4-ES-2012-0004, and at the 
Service's Tennessee Fish and Wildlife Office. You may obtain field 
office location information by contacting one of the Service regional 
offices, the addresses of which are listed at 50 CFR 2.2.
    (5) An overview of critical habitat locations for the fluted 
kidneyshell in Alabama, Tennessee, Kentucky, and Virginia follows:

[[Page 60847]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.001

    (6) Unit FK1: Horse Lick Creek, Rockcastle and Jackson Counties, 
Kentucky.
    (i) The unit includes approximately 19 river kilometers (rkm) (12 
river miles (rmi)) of Horse Lick Creek, in Rockcastle and Jackson 
Counties, KY. It includes the mainstem of Horse Lick Creek from its 
confluence with the Rockcastle River (-84.13780, 37.31991) upstream to 
Clover Bottom Creek (-84.12200, 37.40879).
    (ii) Map of Units FK1 and FK2 follows:

[[Page 60848]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.002

    (7) Unit FK2: Middle Fork Rockcastle River, Jackson County, 
Kentucky.
    (i) The unit includes 12.5 rkm (7.7 rmi) of the Middle Fork 
Rockcastle River from its confluence with the Rockcastle River (-
84.11895, 37.33581) upstream to its confluence with Indian Creek and 
Laurel Fork E (-84.04897, 37.36765) in Jackson County, KY.
    (ii) Map of Units FK1 and FK2 is provided at paragraph (6)(ii) of 
this entry.
    (8) Unit FK3: Rockcastle River, Pulaski, Laurel, and Rockcastle 
Counties, Kentucky.
    (i) The unit includes approximately 70 rkm (43 rmi) of the 
Rockcastle River from the backwaters of Lake Cumberland near its 
confluence with Cane Creek along the Laurel and Pulaski County line, KY 
(-84.30594, 37.03423), upstream to its confluence with Horse Lick Creek 
along the Laurel and Rockcastle County line, KY (-84.13766, 37.31944).
    (ii) Map of Unit FK3 follows:

[[Page 60849]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.003

    (9) Unit FK4: Buck Creek, Pulaski County, Kentucky.
    (i) This unit includes 61 rkm (38 rmi) of Buck Creek from State 
Route 192 (-84.42681, 37.05977) upstream to Route 328 (-84.55492, 
37.32430), Pulaski County, KY.
    (ii) Map of Unit FK4 follows:

[[Page 60850]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.004

    (10) Unit FK5: Rock Creek, McCreary County, Kentucky.
    (i) The unit includes approximately 19 rkm (12 rmi) of Rock Creek 
from its confluence with White Oak Creek (-84.69103, 36.65145) upstream 
to the low water crossing at rkm 25.6 (rmi 15.9) (-84.58888, 36.70800) 
in McCreary County, KY.
    (ii) Map of Units FK5 and FK6 follows:

[[Page 60851]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.005

    (11) Unit FK6: Little South Fork Cumberland River, McCreary and 
Wayne Counties, Kentucky.
    (i) The unit includes 65.5 rkm (40.7 rmi) of the Little South Fork 
Cumberland River from its confluence with the Big South Fork Cumberland 
River (-84.58269, 36.82690), where it is the dividing line between 
Wayne and McCreary Counties, upstream to its confluence with Dobbs 
Creek (-84.85344, 36.62588) in Wayne County, KY.
    (ii) Map of Units FK5 and FK6 is provided at paragraph (10)(ii) of 
this entry.
    (12) Unit FK7: Big South Fork Cumberland River, Fentress, Morgan, 
and Scott Counties, Tennessee, and McCreary County, Kentucky.
    (i) The unit includes approximately 45 rkm (28 rmi) of the Big 
South Fork of the Cumberland River from its confluence with Laurel 
Crossing Branch downstream of Big Shoals (-84.53642, 36.64114), 
McCreary County, KY, upstream to its confluence with Clear Fork and of 
the New River (-84.62394, 36.42475), Scott County, TN. This unit also 
includes 32.3 rkm (20.0 rmi) of Clear Fork from its confluence with the 
Big South Fork and New River (-84.62394, 36.42475) in Scott County, TN, 
upstream to its confluence with Crooked Creek (-84.78637, 36.32533) 
along the Fentress and Morgan County

[[Page 60852]]

line, TN. This unit also includes 14.7 rkm (9.1 rmi) of the New River 
from its confluence with the Big South Fork (-84.62394, 36.42475) 
upstream to the Highway 27 Bridge crossing (-84.55290, 36.38279) in 
Scott County, TN.
    (ii) Map of Unit FK7 follows:
    [GRAPHIC] [TIFF OMITTED] TP04OC12.006
    
    (13) Unit FK8: Wolf River and Town Branch, Pickett and Fentress 
Counties, Tennessee.
    (i) The unit includes 41.0 rkm (25.5 rmi) of the Wolf River from 
its inundation at Dale Hollow Lake (-85.14414, 36.60670) in Pickett 
County, TN, upstream to its confluence with Delk Creek (-84.91064, 
36.52784) in Fentress County, TN. This unit also includes 3.4 rkm (2.0 
rmi) of Town Branch from its confluence with Wolf River (-85.11787, 
36.58321) upstream to its headwaters (-85.12136, 36.55947) in Pickett 
County, TN.
    (ii) Map of Unit FK8 follows:

[[Page 60853]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.007

    (14) Unit FK9: West Fork Obey River, Overton County, Tennessee.
    (i) The unit includes approximately 19 rkm (12 rmi) of the West 
Fork Obey River from the Highway 52 Bridge crossing (-85.17410, 
36.39731) upstream to its confluence with Dry Hollow Creek (-85.20747, 
36.25989) in Overton County, TN.
    (ii) Map of Unit FK9 follows:

[[Page 60854]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.008

    (15) Unit FK10: Indian Creek, Tazewell County, Virginia.
    (i) The unit includes 6.7 rkm (4.2 rmi) of Indian Creek from its 
confluence with the Clinch River (-81.76608, 37.08893) upstream to the 
fourth Norfolk Southern Railroad crossing at Van Dyke (-81.71975, 
37.11206) in Tazewell County, VA.
    (ii) Map of Units FK10 and FK11 follows:

[[Page 60855]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.009

    (16) Unit FK11: Little River, Russell and Tazewell Counties, 
Virginia.
    (i) The unit includes approximately 50 rkm (31 rmi) of Little River 
from its confluence with the Clinch River (-81.92582, 37.00223) in 
Russell County, VA, upstream to its confluence with Liberty and Maiden 
Spring Creeks (-81.67240, 37.03760) in Tazewell County, VA.
    (ii) Map of Units FK10 and FK11 is provided at paragraph (15)(ii) 
of this entry.
    (17) Unit FK12: North Fork Holston River, Smyth and Bland Counties, 
Virginia.
    (i) The unit includes approximately 67 rkm (42 rmi) of the North 
Fork Holston River from its confluence with Beaver Creek (-81.70277, 
36.90825), upstream of Saltville, in Smyth County, VA, upstream to 
Ceres (-81.33775, 37.01035), Bland County, VA.
    (ii) Map of Unit FK12 follows:

[[Page 60856]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.010

    (18) Unit FK13: Middle Fork Holston River, Washington, Smyth, and 
Wythe Counties, Virginia.
    (i) The unit includes approximately 89 rkm (55 rmi) of the Middle 
Fork Holston River from its inundation at South Holston Lake (-
81.90427, 36.66338) in Washington County, VA, upstream to its 
headwaters (-81.31345, 36.88666) in Wythe County, VA.
    (ii) Map of Unit FK13 follows:

[[Page 60857]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.011

    (19) Unit FK14: Big Moccasin Creek, Scott and Russell Counties, 
Virginia.
    (i) The unit includes approximately 33 rkm (21 rmi) of Big Moccasin 
Creek from the Highway 71 Bridge crossing (-82.48361, 36.69109) in 
Scott County, VA, upstream to the Route 612 Bridge crossing (-82.32348, 
36.73740) near Collinwood in Russell County, VA.
    (ii) Map of Unit FK14 follows:

[[Page 60858]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.012

    (20) Unit FK15: Copper Creek, Scott County, Virginia.
    (i) The unit includes 55.5 rkm (34.5 rmi) of Copper Creek from its 
confluence with the Clinch River (-82.74538, 36.65544) upstream to the 
Highway 71 Bridge crossing (-82.43514, 36.73473) in Scott County, VA.
    (ii) Map of Unit FK15 follows:

[[Page 60859]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.013

    (21) Unit FK16: Clinch River, Hancock County, Tennessee, and Scott, 
Russell, and Tazewell Counties, Virginia.
    (i) The unit includes 263 rkm (163 rmi) of the Clinch River from 
rkm 255 (rmi 159) immediately below Grissom Island (-83.40106, 
36.43081) in Hancock County, TN, upstream to its confluence with Indian 
Creek near Cedar Bluff (-81.74999, 37.07995), Tazewell County, VA.
    (ii) Map of Unit FK16 follows:

[[Page 60860]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.014

    (22) Unit FK17: Powell River, Claiborne and Hancock Counties, 
Tennessee, and Lee County, Virginia.
    (i) The unit includes approximately 153 rkm (95 rmi) of the Powell 
River from the U.S. 25E Bridge (-83.63102, 36.54143) in Claiborne 
County, TN, upstream to rkm 256 (rmi 159) (-82.98111, 36.75730, 
upstream of Rock Island in the vicinity of Pughs) in Lee County, VA.
    (ii) Map of Unit FK17 follows:

[[Page 60861]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.015

    (23) Unit FK18: Nolichucky River, Cocke, Hamblen, and Greene 
Counties, Tennessee.
    (i) The unit includes approximately 52 rkm (32 rmi) of the 
Nolichucky River from rkm 14 (rmi 9), approximately 0.6 rkm (0.4 rmi) 
upstream of Enka Dam (-83.19630, 36.12970), where it divides Hamblen 
and Cocke Counties, TN, upstream to its confluence with Pigeon Creek, 
just upstream of the Highway 321 Bridge crossing (-82.92926, 36.07545), 
in Greene County, TN.
    (ii) Map of Unit FK18 follows:

[[Page 60862]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.016

    (24) Unit FK19: Holston River, Knox, Grainger, and Jefferson 
Counties, Tennessee.
    (i) The unit includes approximately 85 rkm (53 rmi) of the Holston 
River from its confluence with the French Broad River (-83.84967, 
35.95903) in Knox County, TN, upstream to the base of Cherokee Dam at 
rkm 83.7 (rmi 52.3) (-83.49855, 36.16666) along the Grainger and 
Jefferson County, TN, line.
    (ii) Map of Units FK19 and FK20 follows:

[[Page 60863]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.017

    (25) Unit FK20: French Broad River, Knox and Sevier Counties, 
Tennessee.
    (i) The unit includes approximately 56 rkm (35 rmi) of the French 
Broad River from its confluence with the Holston River (-83.84967, 
35.95903) in Knox County, TN, upstream to the base of Douglas Dam at 
rkm 51.7 (rmi 32.3) (-83.53821, 35.96073) in Sevier County, TN.
    (ii) Map of Units FK19 and FK20 is provided at paragraph (24)(ii) 
of this entry.
    (26) Unit FK21: Hiwassee River, Polk County, Tennessee.
    (i) The unit includes approximately 24 rkm (15 rmi) of the Hiwassee 
River from the Highway 315 Bridge crossing (-84.50234, 35.18875) 
upstream to the Highway 68 Bridge crossing (-84.31728, 35.16811) in 
Polk County, TN.
    (ii) Map of Unit FK21 follows:

[[Page 60864]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.018

    (27) Unit FK22: Elk River, Limestone County, Alabama, and Giles, 
Lincoln, Franklin, and Moore Counties, Tennessee.
    (i) The unit includes approximately 164 rkm (102 rmi) of the Elk 
River from its inundation at Wheeler Lake (-87.06503, 34.89788) in 
Limestone County, AL, upstream to its confluence with Farris Creek (-
86.31996, 35.16288) at the dividing line between Franklin and Moore 
Counties, TN.
    (ii) Map of Unit FK22 follows:

[[Page 60865]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.019

    (28) Unit FK23: Duck River, Humphreys, Perry, Hickman, Maury, 
Marshall, and Bedford Counties, Tennessee.
    (i) The unit includes approximately 348 rkm (216 rmi) of the Duck 
River from its inundation at Kentucky Lake (-87.88011, 36.00244) in 
Humphreys County, TN, upstream to its confluence with Flat Creek (-
86.48778, 35.47209) near Shelbyville in Bedford County, TN.
    (ii) Map of Unit FK23 follows:

[[Page 60866]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.020

    (29) Unit FK24: Buffalo River, Humphreys and Perry Counties, 
Tennessee.
    (i) The unit includes 50 rkm (31 rmi) of the Buffalo River from its 
confluence with the Duck River (-87.84261, 35.99477) in Humphreys 
County, TN, upstream to its confluence with Cane Creek (-87.78718, 
35.72298) in Perry County, TN.
    (ii) Map of Unit FK24 follows:

[[Page 60867]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.021

Slabside Pearlymussel (Pleuronaia dolabelloides)
    (1) Critical habitat units are depicted on the maps below for 
Colbert, Jackson, Limestone, Madison, and Marshall Counties, Alabama; 
Tishomingo County, Mississippi; Bedford, Bledsoe, Claiborne, Cocke, 
Franklin, Giles, Greene, Hamblen, Hancock, Hickman, Humphreys, Lincoln, 
Marion, Marshall, Maury, Moore, Perry, Polk, and Sequatchie Counties, 
Tennessee; and Bland, Lee, Russell, Scott, Smyth, Tazewell, Washington, 
and Wythe Counties, Virginia.
    (2) Within these areas, the primary constituent elements of the 
physical or biological features essential to the conservation of 
slabside pearlymussel consist of five components:
    (i) Riffle habitats within large, geomorphically stable stream 
channels (channels that maintain lateral dimensions, longitudinal 
profiles, and sinuosity patterns over time without an aggrading or 
degrading bed elevation).
    (ii) Stable substrates of sand, gravel, and cobble with low to 
moderate amounts of fine sediment and containing flow refugia with low 
shear stress.
    (iii) A natural hydrologic flow regime (magnitude, frequency, 
duration, and seasonality of discharge over time) necessary to maintain 
benthic habitats where the species are found, and connectivity of 
rivers with the floodplain, allowing the exchange of nutrients and 
sediment for habitat maintenance, food availability for all life 
stages, and spawning habitat for native fishes.
    (iv) Water quality with low levels of pollutants and including a 
natural

[[Page 60868]]

temperature regime, pH (between 6.0 to 8.5), oxygen content (not less 
than 5.0 milligrams/liter), hardness, and turbidity necessary for 
normal behavior, growth, and viability of all life stages.
    (v) The presence of abundant fish hosts necessary for recruitment 
of the slabside pearlymussel.
    (3) Critical habitat does not include manmade structures (such as 
buildings, aqueducts, dams, roads, and other paved areas) and the land 
on which they are located existing within the legal boundaries on the 
effective date of this rule.
    (4) Critical habitat map units. Data layers defining map units were 
created with USGS National Hydrography Dataset (NHD\+\) GIS data. The 
1:100,000 river reach (route) files were used to calculate river 
kilometers and miles. ESRIs ArcGIS 10.0 software was used to determine 
longitude and latitude coordinates using decimal degrees. The 
projection used in mapping all units was USA Contiguous Albers Equal 
Area Conic USGS version, NAD 83, meters. The following data sources 
were referenced to identify features (like roads and streams) used to 
delineate the upstream and downstream extents of critical habitat 
units: NHD\+\ flowline and waterbody data, 2011 Navteq roads data, USA 
Topo ESRI online basemap service, DeLorme Atlas and Gazetteers, and 
USGS 7.5 minute topographic maps. The maps in this entry, as modified 
by any accompanying regulatory text, establish the boundaries of the 
critical habitat designation. The coordinates or plot points or both on 
which each map is based are available to the public at the field office 
Internet site (https://www.fws.gov/cookeville), https://www.regulations.gov at Docket No. FWS-R4-ES-2012-0004, and at the 
Service's Tennessee Fish and Wildlife Office. You may obtain field 
office location information by contacting one of the Service regional 
offices, the addresses of which are listed at 50 CFR 2.2.
    (5) An overview of critical habitat locations for the slabside 
pearlymussel in Mississippi, Alabama, Tennessee, and Virginia follows:

[[Page 60869]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.022

    (6) Unit SP1: North Fork Holston River, Smyth and Bland Counties, 
Virginia.
    (i) The unit includes approximately 67 river kilometers (rkm) (42 
river miles (rmi)) of the North Fork Holston River from its confluence 
with Beaver Creek (-81.70277, 36.90825), upstream of Saltville, in 
Smyth County, VA, upstream to Ceres (-81.33775, 37.01035), Bland 
County, VA.
    (ii) Map of Unit SP1 follows:

[[Page 60870]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.023

    (7) Unit SP2: Middle Fork Holston River, Washington, Smyth, and 
Wythe Counties, Virginia.
    (i) The unit includes approximately 89 rkm (55 rmi) of the Middle 
Fork Holston River from its inundation at South Holston Lake (-
81.90427, 36.66338) in Washington County, VA, upstream to its 
headwaters (-81.31345, 36.88666) in Wythe County, VA.
    (ii) Map of Unit SP2 follows:

[[Page 60871]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.024

    (8) Unit SP3: Big Moccasin Creek, Scott and Russell Counties, 
Virginia.
    (i) The unit includes approximately 33 rkm (21 rmi) of Big Moccasin 
Creek from the Highway 71 Bridge crossing (-82.48361, 36.69109) in 
Scott County, VA, upstream to the Route 612 Bridge crossing (-82.32348, 
36.73740) near Collinwood in Russell County, VA.
    (ii) Map of Unit SP3 follows:

[[Page 60872]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.025

    (9) Unit SP4: Clinch River, Hancock County, Tennessee, and Scott, 
Russell, and Tazewell Counties, Virginia.
    (i) The unit includes 263 rkm (163 rmi) of the Clinch River from 
rkm 255 (rmi 159) immediately below Grissom Island (-83.40106, 
36.43081) in Hancock County, TN, upstream to its confluence with Indian 
Creek near Cedar Bluff (-81.74999, 37.07995), Tazewell County, VA.
    (ii) Map of Unit SP4 follows:

[[Page 60873]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.026

    (10) Unit SP5: Powell River, Claiborne and Hancock Counties, 
Tennessee, and Lee County, Virginia.
    (i) The unit includes approximately 153 rkm (95 rmi) of the Powell 
River from the U.S. 25E Bridge (-83.63102, 36.54143) in Claiborne 
County, TN, upstream to rkm 256 (rmi 159) (-82.98111, 36.75730, 
upstream of Rock Island in the vicinity of Pughs) in Lee County, VA.
    (ii) Map of Unit SP5 follows:

[[Page 60874]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.027

    (11) Unit SP6: Nolichucky River, Cocke, Hamblen, and Greene 
Counties, Tennessee.
    (i) The unit includes approximately 52 rkm (32 rmi) of the 
Nolichucky River from rkm 14 (rmi 9), approximately 0.6 rkm (0.4 rmi) 
upstream of Enka Dam (-83.19630, 36.12970), where it divides Hamblen 
and Cocke Counties, TN, upstream to its confluence with Pigeon Creek, 
just upstream of the Highway 321 Bridge crossing (-82.92926, 36.07545), 
in Greene County, TN.
    (ii) Map of Unit SP6 follows:

[[Page 60875]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.028

    (12) Unit SP7: Hiwassee River, Polk County, Tennessee.
    (i) The unit includes approximately 24 rkm (15 rmi) of the Hiwassee 
River from the Highway 315 Bridge crossing (-84.50234, 35.18875) 
upstream to the Highway 68 Bridge crossing (-84.31728, 35.16811) in 
Polk County, TN.
    (ii) Map of Unit SP7 follows:

[[Page 60876]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.029

    (13) Unit SP8: Sequatchie River, Marion, Sequatchie, and Bledsoe 
Counties, Tennessee.
    (i) The unit includes approximately 151 rkm (94 rmi) of the 
Sequatchie River from the Highway 41, 64, 72, 2 Bridge crossing (-
85.60583, 35.06576) in Marion County, TN, upstream to the Ninemile 
Cross Road Bridge crossing (-85.08304, 35.69162) in Bledsoe County, TN.
    (ii) Map of Unit SP8 follows:

[[Page 60877]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.030

    (14) Unit SP9: Paint Rock River, Madison, Marshall, and Jackson 
Counties, Alabama.
    (i) The unit includes approximately 86 rkm (53 rmi) of the Paint 
Rock River from the Highway 431 Bridge crossing (-86.39109, 34.49926) 
along the Madison and Marshall County line, AL, upstream to Estill Fork 
(-86.17048, 34.89811); approximately 11 rkm (7 rmi) of Larkin Fork from 
its confluence with the Paint Rock River (-86.20833, 34.86218) upstream 
to its confluence with Bear Creek (-86.22512, 34.94205) in Jackson 
County, AL. This unit also includes approximately 13 rkm (8 rmi) of 
Estill Fork from its confluence with the Paint Rock River (-86.17048, 
34.89813) upstream to its confluence with Bull Run (-86.15283, 
34.99118) in Jackson County, AL. This unit also includes approximately 
16 rkm (10 rmi) of Hurricane Creek from its confluence with the Paint 
Rock River (-86.17048, 34.89813) upstream to its confluence with Turkey 
Creek (-86.09441, 34.98370) in Jackson County, AL.
    (ii) Map of Unit SP9 follows:

[[Page 60878]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.031

    (15) Unit SP10: Elk River, Limestone County, Alabama, and Giles, 
Lincoln, Franklin, and Moore Counties, Tennessee.
    (i) The unit includes approximately 164 rkm (102 rmi) of the Elk 
River from its inundation at Wheeler Lake (-87.06503, 34.89788) in 
Limestone County, AL, upstream to its confluence with Farris Creek (-
86.31996, 35.16288) at the dividing line between Franklin and Moore 
Counties, TN.
    (ii) Map of Unit SP10 follows:

[[Page 60879]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.032

    (16) Unit SP11: Bear Creek, Colbert County, Alabama, and Tishomingo 
County, Mississippi.
    (i) The unit includes approximately 42 rkm (26 rmi) of Bear Creek 
from its inundation at Pickwick Lake at rkm 37 (rmi 23) (-88.08373, 
34.68909) in Colbert County, AL, upstream through Tishomingo County, 
MS, and ending at the Mississippi-Alabama State line (-88.15388, 34. 
49139).
    (ii) Map of Unit SP11 follows:

[[Page 60880]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.033

    (17) Unit SP12: Duck River, Humphreys, Perry, Hickman, Maury, 
Marshall, and Bedford Counties, Tennessee.
    (i) The unit includes approximately 348 rkm (216 rmi) of the Duck 
River from its inundation at Kentucky Lake (-87.88011, 36.00244) in 
Humphreys County, TN, upstream to its confluence with Flat Creek (-
86.48778, 35.47209) near Shelbyville in Bedford County, TN.
    (ii) Map of Unit SP12 follows:

[[Page 60881]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.034

    (18) Unit SP13: Buffalo River, Humphreys and Perry Counties, 
Tennessee.
    (i) The unit includes 50 rkm (31 rmi) of the Buffalo River from its 
confluence with the Duck River (-87.84261, 35.99477) in Humphreys 
County, TN, upstream to its confluence with Cane Creek (-87.78718, 
35.72298) in Perry County, TN.
    (ii) Map of Unit SP13 follows:

[[Page 60882]]

[GRAPHIC] [TIFF OMITTED] TP04OC12.035

* * * * *

    Dated: September 17, 2012.
Michael J. Bean,
Acting Principal Deputy Assistant Secretary for Fish and Wildlife and 
Parks.
[FR Doc. 2012-24019 Filed 10-3-12; 8:45 am]
BILLING CODE 4310-55-P