[Federal Register Volume 71, Number 108 (Tuesday, June 6, 2006)]
[Proposed Rules]
[Pages 32746-32796]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-5075]



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Part III





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; Critical Habitat for 
Five Endangered and Two Threatened Mussels in Four Northeast Gulf of 
Mexico Drainages; Proposed Rule

  Federal Register / Vol. 71, No. 108 / Tuesday, June 6, 2006 / 
Proposed Rules  

[[Page 32746]]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AU87


Endangered and Threatened Wildlife and Plants; Critical Habitat 
for Five Endangered and Two Threatened Mussels in Four Northeast Gulf 
of Mexico Drainages

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 
designate critical habitat for the endangered fat threeridge, 
shinyrayed pocketbook, Gulf moccasinshell, Ochlockonee moccasinshell, 
and oval pigtoe, and the threatened Chipola slabshell and purple 
bankclimber (collectively referred to as the seven mussels), pursuant 
to the Endangered Species Act of 1973, as amended (Act). We propose to 
designate 11 units encompassing approximately 1,864 kilometers (1,158 
miles) of river and stream channels as critical habitat. Proposed 
critical habitat includes portions of the Econfina Creek drainage in 
Florida, the Apalachicola--Chattahoochee--Flint River drainage in 
Alabama, Florida, and Georgia, the Ochlockonee River drainage in 
Florida and Georgia, and the Suwannee River drainage in Florida.

DATES: We will accept comments from all interested parties until August 
7, 2006. We must receive requests for public hearings, in writing, at 
the address shown in the ADDRESSES section by July 21, 2006.

ADDRESSES: If you wish to comment, you may submit your comments and 
materials concerning this proposal by any one of the following methods:
    1. You may submit written comments and information to the Field 
Supervisor, U.S. Fish and Wildlife Service, 1601 Balboa Avenue, Panama 
City, Florida 32405.
    2. You may hand-deliver written comments to our office, at the 
above address.
    3. You may send comments by electronic mail (e-mail) to 
[email protected]. Please see the ``Public Comments Solicited'' 
section under SUPPLEMENTARY INFORMATION for file format and other 
information about electronic filing.
    4. You may fax your comments to 850-763-2177.
    5. Federal eRulemaking Portal: http://www.regulations.gov. Follow 
the instructions for submitting comments.
    Comments and materials received, as well as supporting 
documentation used in the preparation of this proposed rule, will be 
available for public inspection, by appointment, during normal business 
hours at U.S. Fish and Wildlife Service, 1601 Balboa Avenue, Panama 
City, Florida 32405 (telephone 850-769-0552).

FOR FURTHER INFORMATION CONTACT: Jerry Ziewitz at the address above 
(telephone 850-769-0552 ext. 223; facsimile 850-763-2177).

SUPPLEMENTARY INFORMATION:

Public Comments Solicited

    We intend that any final action resulting from this proposal will 
be as accurate and as effective as possible. Therefore, comments or 
suggestions from the public, other concerned governmental agencies, the 
scientific community, industry, or any other interested party 
concerning this proposed rule are hereby solicited. We particularly 
seek comments concerning:
    (1) The reasons any habitat should or should not be determined to 
be critical habitat as provided by section 4 of the Act (16 U.S.C. 1531 
et seq.), including whether the benefit of designation will outweigh 
any threats to the species due to designation;
    (2) Specific information on the amount and distribution of habitat 
for the seven mussels, including areas occupied by the seven mussels at 
the time of listing and containing the features essential to the 
conservation of the species, and areas not occupied at the time of 
listing that are essential to the conservation of the species;
    (3) Whether the middle section of the Flint River complex, between 
the confluence of Gum Creek and the confluence of Auchumpkee/
Ulcohatchee Creek, has the Primary Constituent Elements for the 
mussels, is occupied by the mussels, or is essential to the 
conservation of the mussels;
    (4) Land use designations and current or planned activities in the 
subject areas and their possible impacts on proposed critical habitat;
    (5) Any foreseeable economic, national security, or other potential 
impacts resulting from the proposed designation and, in particular, any 
impacts on small entities; and
    (6) Whether our approach to designating critical habitat could be 
improved or modified in any way to provide for greater public 
participation and understanding, or to assist us in accommodating 
public concerns and comments.
    If you wish to comment, you may submit your comments and materials 
concerning this proposal by any one of several methods (see ADDRESSES 
section). Please submit e-mail comments to [email protected] in 
ASCII file format and avoid the use of special characters or any form 
of encryption. Please also include ``Attn: 7 mussels--RIN 1018-AU87'' 
in your e-mail subject header, and your name and return address in the 
body of your message. If you do not receive a confirmation from the 
system that we have received your message, contact us directly by 
calling our Panama City, Florida, Fish and Wildlife Office at phone 
number 850-769-0552. Please note that the e-mail address 
[email protected] will be closed out at the termination of the 
public comment period.
    Our practice is to make comments, including names and home 
addresses of respondents, available for public review during regular 
business hours. Individual respondents may request that we withhold 
their home addresses from the rulemaking record, which we will honor to 
the extent allowable by law. There also may be circumstances in which 
we would withhold from the rulemaking record a respondent's identity, 
as allowable by law. If you wish us to withhold your name or address, 
you must state this prominently at the beginning of your comment, but 
you should be aware that the Service may be required to disclose your 
name and address pursuant to the Freedom of Information Act. However, 
we will not consider anonymous comments. We will make all submissions 
from organizations or businesses, and from individuals identifying 
themselves as representatives or officials of organizations or 
businesses, available for public inspection in their entirety. Comments 
and materials received will be available for public inspection, by 
appointment, during normal business hours at the above address.

Role of Critical Habitat in Actual Practice of Administering and 
Implementing the Act

    Attention to and protection of habitat is paramount to successful 
conservation actions. The role that designation of critical habitat 
plays in protecting habitat of listed species, however, is often 
misunderstood. There are significant limitations on the regulatory 
effect of designation under Act section 7(a)(2). In brief, (1) 
designation provides additional protection to habitat only where there 
is a Federal nexus; (2) the protection is relevant only when, in the

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absence of designation, destruction or adverse modification of the 
critical habitat would in fact take place (in other words, other 
statutory or regulatory protections, policies, or other factors 
relevant to agency decision-making would not prevent the destruction or 
adverse modification); and (3) designation of critical habitat triggers 
the prohibition of destruction or adverse modification of that habitat, 
but it does not require specific actions to restore or improve habitat.
    Currently, only 475 species, or 36 percent of the 1,311 listed 
species in the U.S. under the jurisdiction of the Service, have 
designated critical habitat. We address the habitat needs of all 1,311 
listed species through conservation mechanisms such as listing, section 
7 consultations, the section 4 recovery planning process, the section 9 
protective prohibitions of unauthorized take, section 6 funding to the 
States, the section 10 incidental take permit process, and cooperative, 
non-regulatory efforts with private landowners. The Service believes 
that it is these measures that may make the difference between 
extinction and survival for many species.
    In considering exclusions of areas proposed for designation, we 
evaluated the benefits of designation in light of Gifford Pinchot Task 
Force v. United States Fish and Wildlife Service (378 F. 3d 1059 (9th 
Cir 2004). In that case, the Ninth Circuit invalidated the Service's 
regulation defining ``destruction or adverse modification of critical 
habitat.'' In response, on December 9, 2004, the Director issued 
guidance to be considered in making section 7 adverse modification 
determinations. This proposed critical habitat designation does not use 
the invalidated regulation in our consideration of the benefits of 
including areas in this final designation. Rather, it relies on the 
guidance issued by the Director in response to the Gifford Pinchot 
decision (see ``Adverse Modification Standard'' discussion below). The 
Service will carefully manage future consultations that analyze impacts 
to designated critical habitat, particularly those that appear to be 
resulting in an adverse modification determination. Such consultations 
will be reviewed by the Regional Office prior to finalizing to ensure 
that an adequate analysis has been conducted that is informed by the 
Director's guidance.
    On the other hand, to the extent that designation of critical 
habitat provides protection, that protection can come at significant 
social and economic cost. In addition, the mere administrative process 
of designation of critical habitat is expensive, time-consuming, and 
controversial. The current statutory framework of critical habitat, 
combined with past judicial interpretations of the statute, make 
critical habitat the subject of excessive litigation. As a result, 
critical habitat designations are driven by litigation and courts 
rather than biology, and made at a time and under a time frame that 
limits our ability to obtain and evaluate the scientific and other 
information required to make the designation most meaningful.
    In light of these circumstances, the Service believes that 
additional agency discretion would allow our focus to return to those 
actions that provide the greatest benefit to the species most in need 
of protection.

Procedural and Resource Difficulties in Designating Critical Habitat

    We have been inundated with lawsuits for our failure to designate 
critical habitat, and we face a growing number of lawsuits challenging 
critical habitat determinations once they are made. These lawsuits have 
subjected the Service to an ever-increasing series of court orders and 
court-approved settlement agreements, compliance with which now 
consumes nearly the entire listing program budget. This leaves the 
Service with little ability to prioritize its activities to direct 
scarce listing resources to the listing program actions with the most 
biologically urgent species conservation needs.
    The consequence of the critical habitat litigation activity is that 
limited listing funds are used to defend active lawsuits, to respond to 
Notices of Intent (NOIs) to sue relative to critical habitat, and to 
comply with the growing number of adverse court orders. As a result, 
listing petition responses, the Service's own proposals to list 
critically imperiled species, and final listing determinations on 
existing proposals are all significantly delayed.
    The accelerated schedules of court-ordered designations have left 
the Service with limited ability to provide for public participation or 
to ensure a defect-free rulemaking process before making decisions on 
listing and critical habitat proposals, due to the risks associated 
with noncompliance with judicially imposed deadlines. This in turn 
fosters a second round of litigation in which those who fear adverse 
impacts from critical habitat designations challenge those 
designations. The cycle of litigation appears endless and is expensive, 
thus diverting resources from conservation actions that may provide 
relatively more benefit to imperiled species.
    The costs resulting from the designation include legal costs, the 
cost of preparation and publication of the designation, the analysis of 
the economic effects and the cost of requesting and responding to 
public comment, and in some cases the costs of compliance with the 
National Environmental Policy Act (NEPA; 42 U.S.C. 4371 et seq.). These 
costs, which are not required for many other conservation actions, 
directly reduce the funds available for direct and tangible 
conservation actions.

Background

    In this proposed rule, we intend to discuss only information about 
the seven mussels that is directly relevant to the designation of 
critical habitat. For more information about these seven mussels, 
please refer to our final rule listing fat threeridge, shinyrayed 
pocketbook, Gulf moccasinshell, Ochlockonee moccasinshell, and oval 
pigtoe as endangered, and Chipola slabshell and purple bankclimber as 
threatened published in the Federal Register on March 16, 1998 (63 FR 
12664) and to our final recovery plan, which is available from the 
Panama City, Florida Fish and Wildlife Office or online at http://www.fws.gov/endangered/recovery/Index.html#plans. The purple 
bankclimber (Elliptoideus sloatianus), Gulf moccasinshell (Medionidus 
penicillatus), Ochlockonee moccasinshell (Medionidus simpsonianus), 
oval pigtoe (Pleurobema pyriforme), shinyrayed pocketbook (Lampsilis 
subangulata), Chipola slabshell (Elliptio chipolaensis), and fat 
threeridge (Amblema neislerii) are variously distributed in four river 
basins that flow into the northeast Gulf of Mexico: Econfina Creek, 
Apalachicola River (a large basin generally labeled with the names of 
its major tributaries, the Chattahoochee and Flint rivers, as the ACF 
River Basin), Ochlockonee River, and Suwannee River.
    The endangered fat threeridge is a medium-sized to large, 
subquadrate, inflated, solid, and heavy-shelled mussel that reaches a 
length of 10.2 centimeters (cm) (4.0 inches (in)). Large specimens are 
so inflated that the width approximates the height. The umbos (bulges 
near the hinge of the shell) are in the anterior quarter of the shell. 
The dark brown to black shell is strongly sculptured with seven or 
eight prominent horizontal parallel plications (ridges).
    The endangered shinyrayed pocketbook is a medium-sized mussel that 
reaches approximately 8.4 cm (3.3 in) in length. The shell is generally 
elongated, with broad, somewhat inflated umbos and a rounded posterior 
ridge. The shell is thin but solid. The

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surface is smooth and shiny and ranges from straw-yellow to chestnut-
brown with a variable number of black to bright emerald-green rays, 
which emanate from the umbo across the disk.
    The shinyrayed pocketbook was listed as federally endangered under 
the scientific name Lampsilis subangulata. The shinyrayed pocketbook 
and three other Lampsilis species that are not federally listed are now 
assigned to the newly recognized genus Hamiota (Roe and Hartfield 2005, 
p. 1). Several characteristics, including glochidia packaging in a 
superconglutinate, placement and shape of the marsupia, and glochidia 
release through the excurrent siphon, support recognition of these 
species as a distinct genus (Roe and Hartfield 2005, p. 1), and we plan 
to implement the name change in a separate rule-making.
    The endangered Gulf moccasinshell is a small mussel that reaches a 
length of about 5.6 cm (2.2 in), is elongate-elliptical or rhomboidal 
in outline, fairly inflated, and has relatively thin valves. The 
ventral margin is nearly straight or slightly rounded. The posterior 
ridge is rounded to slightly angled and intersects the end of the shell 
at the base line. Females tend to have the posterior point above the 
ventral margin and are more inflated than males.
    The endangered Ochlockonee moccasinshell is small, generally under 
5.6 cm (2.2 in) long. It is slightly elongate-elliptical in outline, 
the posterior end obtusely rounded at the median line, and the ventral 
margin broadly curved. The posterior ridge is moderately angular and 
covered in its entire length with well-developed, irregular plications. 
Sculpturing may also extend onto the disk below the ridge. The 
periostracum (outside surface of the shell) is smooth. The color is 
light brown to yellowish green, with dark green rays formed by a series 
of connected chevrons or undulating lines across the length of the 
shell.
    The endangered oval pigtoe is a small-to-medium-sized mussel that 
attains a length of about 6.1 cm (2.4 in). The shell is suboviform and 
compressed. The periostracum is shiny smooth; yellowish, chestnut, or 
dark brown; rayless; and with distinct growth lines. The posterior 
slope is biangulate and forms a blunt point on the posterior margin. 
The umbos are slightly elevated above the hingeline.
    The endangered oval pigtoe is the only species among the seven 
mussels of this proposed rule that occurs in all four Gulf of Mexico 
river basins comprising their collective range: Econfina Creek, ACF, 
Ochlockonee, and Suwannee. Morphological variation across this broad 
range has led to the description of several nominal species since it 
was originally described as Unio pyriformis (Lea 1857, p. 169-172). 
Williams and Butler (1994, p. 111) recognized the form distributed in 
the Ochlockonee and Suwannee River systems as the Florida pigtoe, 
Pleurobema reclusum (Wright 1898, p. 111-112), consistent with Simpson 
(1914, p. 1-1540). However, Turgeon et al. (1998, p. 36) recognized the 
forms from all four basins as one species, P. pyriforme, which was the 
taxonomic classification upon which we relied on for the 1998 final 
rule listing this species as endangered. A recent study using molecular 
genetic techniques compared tissue samples from three of the four 
basins (Econfina Creek, ACF, and Suwannee), and concluded that the 
Suwannee samples were distinctive and warranted specific status as P. 
reclusum (Kandl et al. 2001, p. 10). We acknowledged these findings in 
our 2003 final recovery plan, but have deferred any revisions to the 
listing taxonomy pending review of an analysis that includes samples 
from the Ochlockonee Basin as well. Peer review and publication of a 
genetic analysis of samples from all four basins is expected sometime 
in 2006 (J.D. Williams, USGS, pers. comm. 2005).
    The threatened Chipola slabshell is a medium-sized species reaching 
a length of about 8.4 cm (3.3 in). The shell is ovate to subelliptical, 
somewhat inflated, and with the posterior ridge starting out rounded 
but flattening to form a prominent biangulate margin. The periostracum 
is smooth and chestnut-colored. Dark brown coloration may appear in the 
umbo region, and the remaining surface may exhibit alternating light 
and dark bands.
    The threatened purple bankclimber is a large, heavy-shelled, 
strongly sculptured mussel reaching lengths of 20.5 cm (8.0 in). A 
well-developed posterior ridge extends from the umbo to the posterior 
ventral margin of the shell. The posterior slope and the disk just 
anterior to the posterior ridge are sculptured by several irregular 
plications that vary greatly in development. The umbos are low, 
extending just above the dorsal margin of the shell.

Life History

    The seven mussels are all bivalve mollusks (clams) of the family 
Unionidae. Unionid mussels generally live embedded in the bottom of 
rivers, streams, and other bodies of water. They siphon water into 
their shells and across four gills that are specialized for respiration 
and food collection. Known food items include detritus (disintegrated 
organic debris), diatoms, phytoplankton, zooplankton, and other 
microorganisms (Coker et al. 1921, p. 88; Churchill and Lewis 1924, p. 
462; Fuller 1974, p. 221). Adults are filter feeders and generally 
orient themselves on or near the substrate surface to take food and 
oxygen from the water above them (Kraemer 1979, p. 1085-1096). 
Juveniles typically burrow completely beneath the substrate surface and 
are pedal (foot) feeders (bringing food particles inside the shell for 
ingestion that adhere to the foot while it is extended outside the 
shell) until the structures for filter feeding are more fully developed 
(Gatenby et al. 1996, p. 604; Yeager et al. 1994, p. 221).
    Sexes in unionid mussels are usually separate. Males release sperm 
into the water, which females take in through their siphons during 
feeding and respiration. Eggs are fertilized and retained in the gills 
of the female until the larvae (glochidia) fully develop. The glochidia 
of most unionid species, including all seven species addressed in this 
proposed rule, require a parasitic stage on the fins, gills, or skin of 
a fish to transform into juvenile mussels (for species-specific 
information, see ``Primary Constituent Elements--Fish Hosts''). Females 
release glochidia either separately or in masses termed conglutinates, 
depending on the mussel species. Exceptionally large conglutinates, 
such as those of the shinyrayed pocketbook, are termed 
superconglutinates. The duration of the parasitic stage varies by 
mussel species, water temperature, and perhaps host fish species. When 
the transformation is complete, juvenile mussels normally detach from 
their fish host and sink to the stream bottom where, given suitable 
conditions, they grow and mature to the adult form.

Distribution

    The historical and current range of the seven mussels includes 
portions of four river basins of the northeast Gulf of Mexico in 
Alabama, Florida, and Georgia: Econfina Creek, ACF, Ochlockonee, and 
Suwannee. Of these four basins, the ACF is the largest and the only one 
that extends beyond the Coastal Plain physiographic province into the 
Piedmont of Georgia and Alabama. Two or more of the seven mussels occur 
in each of the four basins, except the Suwannee, in which only the oval 
pigtoe is found. Because large reservoirs are unsuitable as habitat for 
these mussels and the dams that impound them are barriers to the 
movement of their host fishes, their

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range within two of the basins (ACF and Ochlockonee) is divided into 
two or more sub-basins that likely represent the maximum spatial extent 
of potentially interbreeding populations. We estimate that the five 
species listed as endangered are each extirpated from over half of 
their historical ranges, and the two threatened species are extirpated 
from about one-third of their historical ranges (USFWS 2003, p. 77).

Summary of Threats to Surviving Populations

    The declining range and abundance of the seven mussels is due 
mostly to changes in their riverine habitats resulting from dams, 
dredging, mining, channelization, pollution, sedimentation, and water 
withdrawals, and possibly also the introduction of nonnative species, 
such as the Asian clam. Each of these threats affect one or more of the 
physical and biological habitat features that we have identified as 
essential to the conservation of the seven mussels, which we discuss in 
detail under ``Primary Constituent Elements.''
    More than 350 kilometers (km) (217 miles (mi)) of large and small 
river habitat in the ACF and Ochlockonee basins within the current 
range of the seven mussels is inundated by reservoirs. None of the 
seven species are known to persist in impoundments, although a single 
purple bankclimber was found in an impounded portion of the 
Chattahoochee River (C. Stringfellow, Columbus State University, pers. 
comm. 2000). Obligate riverine fishes, some of which may serve as hosts 
for larvae of the seven mussels, are also eliminated by dams and 
impoundments. Several populations of the seven species persist in 
relatively small fragments of the four major river basins that are 
isolated from other populations by impoundments or other large patches 
of unsuitable habitat and by dams or other barriers to dispersal via 
their fish hosts. Habitat fragmentation reduces the probability of 
population persistence (Wilcox and Murphy 1985, p. 879-884), because 
smaller, more isolated populations are less able to rebound from chance 
adverse environmental, demographic, and genetic events (Shaffer 1981, 
p. 131; Lande 1988, p. 1455).
    A variety of activities may induce channel instability that 
adversely affects habitat conditions for mussels. Because impoundments 
block the natural downstream movement of sediment, channel degradation 
is commonly observed in the tailwaters of dams (Williams and Wolman 
1984, p. 14; Lignon et al. 1995, p. 187). The mean bed elevation of the 
Apalachicola River downstream of Jim Woodruff Lock and Dam, which is 
located at the confluence of the Chattahoochee and Flint rivers, has 
degraded about 1.2 to 1.5 meters (m) (4 to 5 feet (ft)) since its 
construction in the late 1950s (Light et al. 1998, p. 21). The main 
channel of the river widened at a rate of about 0.45 m (1.5 ft) per 
year, based on cross sections measured by the U.S. Army Corps of 
Engineers (USACE) between 1980 and 2001 (USACE 2002, p. 1.1-8.3). The 
Apalachicola River near the Chattahoochee-Flint confluence once 
supported a particularly rich mussel bed, which included large numbers 
of fat threeridge and purple bankclimber, but this bed had declined 
substantially in diversity and numbers by the early 1970s (Heard 1975, 
p. 1-31). Although the purple bankclimber persists, the fat threeridge 
is now rare in the upper river (Brim Box and Williams 2000, p. 89). 
Quantitative sampling using substrate sieves at two locations in the 
upper river failed to detect juveniles of any unionid mussels 
(Richardson and Yokley 1996, p. 137). The decline of the rich mussel 
fauna of the Chattahoochee River was attributed partly to erosion from 
intensive farming before the Civil War (van der Schalie 1938, p. 56; 
Clench 1955, p. 96), although substantial erosion continued for several 
more decades (Glenn 1911, p. 1-137; Trimble 1972, p. 454-457). The most 
striking example of this erosion and resulting stream channel 
instability is in the headwaters of Turner Creek, a Chattahoochee River 
tributary in Stewart County, Georgia. The massive amount of sediment 
that washed away was conveyed via Turner Creek over time to the 
Chattahoochee River.

Channelization

    Channelization (straightening a stream course by artificial cutoffs 
and other means for flood control and navigation), dredging, snagging 
(removal of large woody debris), in-stream gravel mining, and other 
forms of direct stream channel modifications may induce channel 
instability. A well-documented example of how direct modifications to a 
stream induced substantial instability is the Homochitto River in 
Mississippi, which incised 5 m (16.4 ft) and widened 450 percent 
following channelization (Kesel and Yodis 1992, p. 99). Hartfield 
(1993, p. 131-141) and Neves et al. (1997, p. 71-72) reviewed the 
adverse effects of channel modifications on freshwater mollusks. 
Dredging in the Apalachicola River to maintain navigability may be 
contributing to observed channel instability in that system (letter 
from G. Carmody, Service, to R. Keyser, USACE, dated August 8, 2003). 
Channel instability induced by gravel mining has probably played a 
significant role in extirpating the Gulf moccasinshell and oval pigtoe 
from the Uchee Creek system (Howard 1997, p. 157), where a small 
population of the shinyrayed pocketbook persists. A recent Service 
stream habitat condition survey in the Ochlockonee Basin found evidence 
of substantial channel instability (actively eroding banks) at only 9 
of 181 sites surveyed, but classified over half of the sites (99) as 
having a moderate risk of bank erosion (H. Blalock-Herod, Service, 
pers. comm. 2006).

Sedimentation

    Sedimentation is widely reported as a contributing factor in the 
decline of stream mussel populations (Kunz 1898, p. 328; Ellis 1931, p. 
5; 1936, p. 29; Imlay 1972, p. 76; Coon et al. 1977, p. 279; Marking 
and Bills 1979, p. 204; Dennis 1985, p. 1-171; Aldridge et al. 1987, p. 
17; Schuster et al. 1989, p. 84; Wolcott and Neves 1990, p. 74; Houp 
1993, p. 93-97; Richter et al. 1997a, p. 1090; Brim Box 1999, p. 1-
108). Sedimentation is the process by which water detaches, transports, 
and deposits soil materials on the substrates of streams, lakes, and 
wetlands. In geomorphically stable stream reaches, sediment input is 
balanced by sediment output, resulting in no net accumulation or loss 
of sediment from the stream bed. Sediment input is increased by a 
variety of human activities that are common in the range of the seven 
mussels. Substantial sediment accumulation is one factor that may 
induce channel instability. Lesser amounts may also adversely affect 
substrate quality for mussels by altering its texture (usually by 
increasing the percentage of fine materials) and by introducing harmful 
pollutants.
    Waters (1995, p. 173-176) reviewed the biological effects of 
sediments in streams, and Mount (1995, p. 1-359) provided an overview 
of the effects of various land uses on stream systems. Brim Box and 
Mossa (1999, p. 99-117) reviewed the effects of sediments and land uses 
specifically on mussels. They identified several activities that may 
affect mussels through sedimentation, including logging, farming, 
ranching, mining, and urbanization. Without adequate measures to 
control erosion, these activities may deliver sediment to streams via 
upland gullies, unpaved roads, road-side ditches, construction sites, 
and other areas of soil disturbance. All of these activities are 
widespread in the current range of the seven mussels.
    Sediment samples from several ACF Basin streams contained elevated

[[Page 32750]]

concentrations of two heavy metals that are harmful to mussels: Copper 
(found throughout the Piedmont) and cadmium (found in large Coastal 
Plain tributaries of the Flint River) (Frick et al. 1998, p. 19). 
Elevated concentrations of heavy metals (such as chromium and cadmium) 
were measured in Asian clams and in sediment samples collected 
downstream of two abandoned battery salvage operations on the Chipola 
River (Winger et al. 1985, p. 141, 144). Farther downstream in the 
Chipola River, the chromium concentrations found in the sediments of 
Dead Lake (Winger et al. 1985, p. 141, 144) are toxic to mussels 
(Havlik and Marking 1987, p. 1-20).

Impoundments

    The operations of several dams and withdrawals of surface and 
groundwater may alter flow regimes to a degree that adversely affects 
mussels. Four portions of the range of the seven mussels are 
immediately downstream of major mainstem dams. The Apalachicola River 
is downstream of Jim Woodruff Lock and Dam (JWLD), which impounds Lake 
Seminole, a large but shallow reservoir in the southwest corner of 
Georgia with a storage capacity of about 86 million meters\3\ (70,000 
acre-feet). Seminole is the downstream-most reservoir in a series of 
much larger reservoirs on the Chattahoochee River with a cumulative 
capacity of about 2.2 billion m\3\ (1.8 million ac-ft), which 
represents about 11 percent of the average annual discharge from JWLD 
(USACE 1998, p. 4.10, 4.48, 4.56). During extended periods without 
substantial rainfall, however, as during 1999 to 2002, the flow of the 
Apalachicola River may consist mostly of releases from storage in the 
Chattahoochee reservoirs.
    The Flint River is impounded by two mainstem reservoirs, Lake 
Blackshear and Lake Worth. By impeding passage of host fishes, these 
dams separate individuals of the shinyrayed pocketbook, Gulf 
moccasinshell, oval pigtoe, and purple bankclimber into at least three 
populations within the basin. Both dams are used for hydropower and are 
licensed to operate generally in a run-of-river mode (releases 
approximately equal reservoir inflow) (USACE 1998, p. 4.48, 4.56), but 
short-term alterations of river flow may occur. A mainstem dam on the 
Ochlockonee River creates Lake Talquin, which is licensed and operated 
in a similar fashion. No dams have been constructed on Econfina Creek 
or the Suwannee River and its major tributaries within the range of the 
seven mussels.

Water Withdrawals

    Water withdrawals for agricultural, municipal, and industrial use 
may reduce stream flow and affect mussels. In the Dougherty Plain of 
the lower Flint River Basin and upper Chipola River Basin, irrigated 
agriculture is the largest consumptive water use (Marella et al. 1993, 
p. 6, 13, 29, 42). Major crops in the region include cotton, peanuts, 
corn, and soybeans, with the largest acreage irrigated by groundwater 
using center pivot sprinkler systems. Due to the porous limestone 
underlying this area, ground and surface waters are highly connected, 
and the base flow of many streams is supported by the discharge of 
springs (Torak et al. 1996, p. 1-106). This area is also the center of 
the current range of several of the seven mussels. Approximately 
172,125 hectares (ha) (425,000 acres (ac)) of cropland were irrigated 
using center pivot systems in a 16-county area of Georgia in the lower 
Flint River Basin, with an additional 30,375 ha (75,000 ac) irrigated 
with surface waters (Litts et al. 2001, p. 23). Using models 
representing surface water--groundwater dynamics in the lower Flint-
upper Chipola area, Albertson and Torak (2002, p. 22) found that 8 of 
37 streams examined (7 of these 37 support listed mussels) were highly 
sensitive to groundwater withdrawal and that during droughts these 
streams may go dry.
    Water supply for municipal and industrial needs are greatest in the 
areas of greatest human population. Several large urban areas 
(population greater than 100,000) are near or within the current range 
of the seven mussels, including Dothan, Alabama; Panama City and 
Tallahassee, Florida; and Albany, Atlanta, and Columbus, Georgia. The 
largest of these is the Atlanta metro area, which extends into the 
headwaters of the Flint River Basin. Population in the 16-county metro 
area is forecast to increase from about 4 million people in 2000 to 
about 8 million in 2030, when regional water planning authorities 
predict water demand will equal available water supply from existing 
and presently planned sources (Ashley 2005, p. 1). Water use will 
likely increase along with increasing human population in each of the 
four basins that support the seven mussels.

Water Quality

    Water quality is reported as impaired or potentially impaired in 
some portions of all four river basins within the current range of the 
seven mussels, according to the water quality agencies of the three 
States in their periodic assessments under Section 305(b) of the Clean 
Water Act (CWA). Although water quality in the smallest of the four 
basins, Econfina Creek, is generally good, mercury accumulation in fish 
populations was cited as a potential impairment in Florida's most 
recent basin status report (FDEP 2003a, p. 71). Barrios and Chelette 
(2004, p. 7) described the hydrologic setting of Econfina Creek, which 
strongly influences its water quality characteristics. Except during 
periods of high rainfall, most of the flow in Econfina Creek derives 
from the discharge of a series of at least 39 spring vents from the 
Floridan Aquifer in the middle section of the creek. The ground water 
contribution zone for these springs is large and encompasses a 
significant portion of the creek's surface water basin. Water quality 
in the Floridan Aquifer is vulnerable to land use activities in this 
contribution zone.
    Water quality in the largest of the four basins, the ACF, varies 
considerably. Two small portions of the seven mussels' current range in 
the ACF are within the State of Alabama: The entire Uchee Creek 
watershed (a Chattahoochee River tributary) and the headwaters of the 
Chipola River watershed (an Apalachicola River tributary). In the 
latter, the Alabama Department of Environmental Management (2004, p. 7) 
reports that Cypress Creek is impaired due to organic enrichment and 
low dissolved oxygen (DO). We have no records of the seven mussels in 
Cypress Creek; however, three of the species are known to occur within 
a few miles downstream of its mouth. In the Florida portion of the ACF, 
several stream segments that support one or more of the seven mussels 
in the Chipola and Apalachicola watersheds are potentially impaired due 
to excessive coliform bacteria, nutrients, un-ionized ammonia, or 
turbidity (FDEP 2003b, p. 1-208). Mercury-based fish advisories apply 
to one or more segments of both watersheds. The current range of the 
seven mussels in the Flint River Basin includes 131 km (81 mi) that are 
reported as not supporting or partially supporting designated uses due 
to departures from Georgia's standards for DO or biological integrity, 
or are under mercury-based fish consumption advisories (GDNR-EPD 2002, 
p. 1/1-9/2). The streams listed include such Flint River tributaries as 
Spring Creek and Kinchafoonee Creek, but not the mainstem. The 
conditions in an additional 58 km (36 mi) of Flint River tributaries 
occupied by the mussels violate the coliform bacteria standard.

[[Page 32751]]

    Water quality is considered impaired in a majority of the mussels' 
range in the Ochlockonee River Basin of Florida and Georgia. In both 
States, the entire mainstem length of the river is impaired or 
potentially impaired by excessive coliform bacteria or nutrients, low 
DO, or is under mercury-based fish consumption advisories (FDEP 2003c, 
p. 1-141; GDNR--EPD 2002, p. 1/1-9/2). A study of water and sediment 
quality in the basin in relation to mussels found that sites with low 
DO or elevated levels of lead, manganese, or ammonia no longer 
supported their historical mussel assemblages, including the listed 
species (Hemming et al. 2005, p. 2).
    The range of the seven mussels in the Suwannee River Basin is 
limited to one species (the oval pigtoe), to the Florida portion of the 
basin, and to one watershed within that portion (the Santa Fe River 
watershed). The oval pigtoe is currently known only from the New River 
and a short segment of Santa Fe itself downstream of the mouth of the 
New River. Most of the New River was listed as impaired due to 
excessive coliform bacteria, excessive nutrients, and low DO in 1998, 
and remains potentially impaired under Florida's current standards 
(FDEP 2003d, p. 1-159).
    Agricultural sources of contaminants in the ACF and Suwannee basins 
include nutrient enrichment from poultry farms and livestock feedlots, 
and pesticides and fertilizers from row crop agriculture (Couch et al. 
1996, p. 1-58; Frick et al. 1998, p. 1-36; Berndt et al. 1998, p. 1-
32). A study by the U.S. Soil Conservation Service (1993, p. 26) (now 
the Natural Resources Conservation Service) in the Flint River system 
determined that between 72 and 75 percent of the nutrients entering 
Lake Blackshear were derived from agricultural sources. Organochlorine 
pesticides were found at levels in ACF Basin streams that often 
exceeded chronic exposure criteria for the protection of aquatic life 
(Buell and Couch 1995, p. 1; Frick et al. 1998, p. 11). Cotton is 
raised in much of the region inhabited by these mussels. One of the 
most important pesticides used in cotton farming, malathion, affects 
mussels physiologically and may decrease respiration and feeding 
ability (Kabeer et al. 1979, p. 71-73). Within the Suwannee River 
basin, nutrient concentrations were greater in agricultural areas and 
nitrates were found to exceed U.S. Environmental Protection Agency 
(USEPA) drinking water standards in 20 percent of the surficial aquifer 
groundwater samples (Berndt et al. 1998, p. 6). Mostly in urban areas, 
pesticide concentrations were found to exceed criteria for protection 
of aquatic life.
    Many pollutants in the ACF Basin originate from urban stormwater 
runoff, developmental activities, and municipal waste water facilities, 
primarily upstream of the fall line (the line marking the relatively 
abrupt elevation transition between the Piedmont physiographic province 
and the coastal plain) (Frick et al. 1998, p. 1-36). Urban catchments 
in Piedmont drainages have higher concentrations of nutrients, heavy 
metals, pesticides, and organic compounds than do agricultural or 
forested ones (Lenat and Crawford 1994, p. 185; Frick et al. 1998, p. 
1-36), and at levels sufficient to affect fish health (Ostrander et al. 
1995, p. 213). Couch et al. (1996, p. 50) counted 137 municipal 
wastewater treatment facilities in the ACF Basin.

Host Fish

    Collectively, eight species of fish are now considered probable 
primary hosts for the larval life stage of four of the seven mussels: 
Largemouth bass, spotted bass, bluegill, redear sunfish, weed shiner, 
sailfin shiner, blackbanded darter, and brown darter (O'Brien and Brim 
Box 1999, p. 136; O'Brien and Williams 2002, p. 150-152) (see ``PCEs--
Fish Hosts''). According to Lee et al. (1980, p. 1-854), the range of 
each of these fishes encompasses the range of the respective mussel(s) 
that successfully parasitized each species in laboratory tests, with 
the possible exception of the sailfin shiner--oval pigtoe association. 
The sailfin shiner does not occur far upstream of the fall line in the 
ACF basin (B. Albanese, GA DNR Wildlife Division, pers. comm. 2006), 
but the oval pigtoe does; therefore, at least one more fish likely 
serves as a host for this species. None of the eight fishes is 
protected under the Act or considered imperiled rangewide (Williams et 
al. 1989, p. 2-20); however, Georgia recognizes the sailfin shiner as a 
species of special concern (State rank ``S3''; rare or uncommon in 
State). The four centrarchid fishes (the two basses, bluegill, and 
redear sunfish) are each classified as game species by the three 
States. Riverine fish populations in the southeast generally have been 
adversely affected by a variety of the same habitat alterations that 
have contributed to the decline of the region's mussel fauna (Etnier 
1997, p. 91; Neves et al. 1997, p. 60; Warren et al. 1997, p. 106, 123-
125, 127, 131).

Non-Native Species

Asian Clam

    The invasion of non-native aquatic species has contributed to the 
decline of several North American mussel species (Neves et al. 1977, p. 
72-75; Strayer 1999, p. 74). Some native mussels may go extinct due to 
the continued spread of the zebra mussel (Dreissena polymorpha), a 
species not yet established in the southeast (Ricciardi et al. 1998, p. 
618). Another non-native bivalve, the Asian clam (Corbicula fluminea), 
is well-established and almost ubiquitous in the range of the seven 
mussels. Reports of Asian clam density vary considerably, from 9 per 
square foot (Flint River, Sickel 1973, p. 11) to over 195 per square 
foot (Santa Fe River, Bass and Hitt 1974, p. 16). In the New River 
(Suwannee River drainage), Blalock and Herod (1999, p. 145-151) found 
an overall density of 8 Asian clams per square foot in an area where 
oval pigtoe density was 0.003 per square foot (Blalock-Herod 2000, p. 
1-72). In one reach of the Apalachicola River immediately downstream of 
Jim Woodruff Lock and Dam, the stream bed is almost entirely covered 
with a layer of live and dead Asian clams several inches deep (J. 
Ziewitz, personal observation). Several researchers have suggested that 
the Asian clam competes with native mussels for food, nutrients, and 
space (Heard 1977, p. 1-177; Kraemer 1979, p. 1094; Clarke 1986, p. 8), 
particularly with juvenile unionids (Neves and Widlak 1987, p. 6). 
Yeager et al. (2000, p. 257) determined that high densities of Asian 
clams reduced survival and growth of newly metamorphosed juvenile 
mussels. However, Asian clams are present at almost all locations where 
the seven mussels for which we are proposing critical habitat in this 
proposed rule are currently found, and the specific impact of this 
species upon native mussels is largely unresolved (Leff et al. 1990, p. 
415; Strayer 1999, p. 90).

Black Carp

    The black carp (Mylopharyngodon piceus) is another introduced 
species that may pose a threat to the seven mussels. Largest of the 
Asiatic carp species, the black carp eats mollusks (snails and 
mussels), and sterile fish are sometimes used in catfish aquaculture to 
control snails that are the intermediate hosts of a catfish parasite 
(Nico et al. 2001, p. 1-124). Escape of substantial numbers of the 
sterile fish could significantly reduce numbers of native mussels where 
the escape occurs, and the establishment of non-sterile black carp in 
the wild could

[[Page 32752]]

conceivably extirpate entire mussel populations.

Previous Federal Actions

    We listed the seven mussels under the Act on March 16, 1998 (63 FR 
12664), and approved a final recovery plan for the seven species on 
September 19, 2003 (68 FR 56647; October 1, 2003). In the final 1998 
rule, we determined that designation of critical habitat was not 
prudent. On March 15, 2004, the Center for Biological Diversity 
(Center) filed a lawsuit in the U.S. District Court for the Northern 
District of Georgia (Civil Action No. 1:04 CV-0729-GET) alleging that 
we violated the Act by failing to designate critical habitat for the 
seven mussels. We entered a settlement agreement with the Center on 
August 31, 2004, which stipulates that the Service would submit for 
publication in the Federal Register, on or before May 30, 2006, a new 
prudency determination, and if designation was determined to be 
prudent, a proposed rule designating critical habitat. This publication 
is our new prudency determination and our proposed rule designating 
critical habitat for the seven mussels.

Critical Habitat

    Critical habitat is defined in section 3 of the Act as--(i) the 
specific areas within the geographical area occupied by a species, at 
the time it is listed in accordance with the Act, on which are found 
those physical or biological features (I) essential to the conservation 
of the species and (II) that may require special management 
considerations or protection; and (ii) specific areas outside the 
geographical area occupied by a 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 which are necessary to 
bring any endangered species or threatened species to the point at 
which the measures provided pursuant to the Act are no longer 
necessary.
    Critical habitat receives protection under section 7 of the Act 
through the prohibition against destruction or adverse modification of 
critical habitat with regard to actions carried out, funded, or 
authorized by a Federal agency. Section 7 requires consultation on 
Federal actions that are 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 government or public access to private lands.
    To be included in a critical habitat designation, the habitat 
within the area occupied by the species must first have features that 
are essential to the conservation of the species. Critical habitat 
designations identify, to the extent known using the best scientific 
data available, habitat areas that provide essential life cycle needs 
of the species (areas on which are found the primary constituent 
elements, as defined at 50 CFR 424.12(b)).
    Habitat occupied at the time of listing may be included in critical 
habitat only if the essential features thereon may require special 
management or protection. Thus, we do not include areas where existing 
management is sufficient to conserve the species. Accordingly, when the 
best available scientific data do not demonstrate that the conservation 
needs of the species so require, we will not designate critical habitat 
in areas outside the geographical area occupied by the species at the 
time of listing. An area currently occupied by the species but was not 
known to be occupied at the time of listing is likely, but not always, 
essential to the conservation of the species and is typically included 
in the critical habitat designation.
    The Service's Policy on Information Standards Under the Endangered 
Species Act, published in the Federal Register on July 1, 1994 (59 FR 
34271), and Section 515 of the Treasury and General Government 
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658) 
and the associated Information Quality Guidelines issued by the 
Service, provide criteria, establish procedures, and provide guidance 
to ensure that decisions made by the Service represent the best 
scientific data available. They require Service 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 
determining which areas are critical habitat, a primary source of 
information is generally the listing package for the species. 
Additional information sources include the recovery plan for the 
species, articles in peer-reviewed journals, conservation plans 
developed by States and counties, scientific status surveys and 
studies, biological assessments, or other unpublished materials and 
expert opinion or personal knowledge. All information is used in 
accordance with the provisions of Section 515 of the Treasury and 
General Government Appropriations Act for Fiscal Year 2001 (Pub. L. 
106-554; H.R. 5658) and the associated Information Quality Guidelines 
issued by the Service.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific data available. Habitat is often 
dynamic, and species may move from one area to another over time. 
Furthermore, we recognize that designation of critical habitat may not 
include all of the habitat areas that may eventually be determined to 
be necessary for the recovery of the species. For these reasons, 
critical habitat designations do not signal that habitat outside the 
designation is unimportant or may not be required for recovery.
    Areas that support populations, but are outside the critical 
habitat designation, will continue to be subject to conservation 
actions implemented under section 7(a)(1) of the Act and to the 
regulatory protections afforded by the section 7(a)(2) jeopardy 
standard, as determined on the basis of the best available information 
at the time of the action. Federally funded or permitted projects 
affecting listed species outside their designated critical habitat 
areas may still result in jeopardy findings in some cases. Similarly, 
critical habitat designations made on the basis of the best available 
information at the time of designation will not control the direction 
and substance of future recovery plans, habitat conservation plans, or 
other species conservation planning efforts, if new information 
available to these planning efforts calls for a different outcome.

Prudency Determination

    Section 4(a)(3) of the Act and its implementing regulations (50 CFR 
424.12) require that, to the maximum extent prudent and determinable, 
we designate critical habitat at the time a species is listed as 
endangered or threatened. Our regulations at 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 activity and the 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. In our March 16, 1998, final rule (63 FR 12664), we determined 
that designating critical habitat was not prudent for the seven mussels 
because it would result in no known benefit to the species and could 
further pose a threat to them through publication of their site-
specific localities. However, several of our determinations that the

[[Page 32753]]

designation of critical habitat would not be prudent have been 
overturned by court decisions (for example, Conservation Council for 
Hawaii v. Babbitt (2 F. Supp. 2d 1280 [D. Hawaii 1998]); and Natural 
Resources Defense Council v. U.S. Department of the Interior (113 F. 3d 
1121, 1125 [9th Cir. 1997])).
    We are already working with Federal and State agencies, private 
individuals, and organizations in carrying out conservation activities 
for the seven mussels, conducting surveys for additional occurrences, 
and assessing habitat conditions. However, critical habitat designation 
may provide additional information to individuals, local and State 
governments, and other entities engaged in long-range planning, since 
areas with features essential to the conservation of the species are 
clearly delineated and, to the extent currently feasible, the primary 
constituent elements of the habitat necessary to the survival of the 
subspecies are specifically identified. Furthermore, although the low 
numbers of these mussels make it unlikely that their populations could 
withstand even moderate collecting pressure or vandalism, we do not 
have specific evidence of taking, collection, vandalism, trade, or 
unauthorized human disturbance.
    Accordingly, we withdraw our previous determination that the 
designation of critical habitat will not benefit the seven mussels and 
will increase the degree of threat to the species. We determine that 
the designation of critical habitat is prudent for these species. At 
this time, we have sufficient information necessary to identify 
specific areas that meet the definition of critical habitat and are, 
therefore, proposing critical habitat for the seven mussels.

Methods

    As required by section 4(b)(1) of the Act, we used the best 
scientific and commercial data available in determining areas that 
contain the physical and biological features essential to the 
conservation of the seven mussels. We reviewed the available 
information pertaining to their historical and current distributions, 
life histories, host fishes, habitats, threats to mussels in general, 
and threats to the seven mussels in particular. This information 
includes our own site-specific species and habitat data; unpublished 
survey reports; notes and communications with other qualified 
biologists or experts; peer-reviewed scientific publications; the final 
listing rule for the seven mussels; and our final recovery plan for the 
seven mussels.
    Our principal sources of information for identifying the specific 
areas within the occupied range of the seven mussels on which are found 
those features essential to their conservation were: the collective 
database of locality records for the seven mussels, which is tabulated 
in our 2003 final recovery plan and has been supplemented with surveys 
completed since then, and the peer-reviewed scientific literature on 
mussels' life history and habitat requirements. Our 1998 final listing 
rule relied extensively upon data obtained in a rangewide status survey 
of the seven mussels commissioned by the Service and conducted in 1991 
and 1992 (cited as Butler (1993, p. 1-30) in the final listing). Most 
of these data were taken in the ACF basin and have since been published 
by Brim Box and Williams (2000, p. 3). Although mussel surveys have 
been conducted since publication of the final listing rule at various 
locations in the four river basins that encompass their known range, 
the 1991-1992 status survey still provides a majority of the most 
recent distributional records for these seven mussels. For purposes of 
this proposed rule, the Service considers the most recent post-1990 
survey data at a particular location as representing a species' current 
presence or absence at that location, and we consider pre-1990 survey 
data as representing historical distribution. We must extend the 
definition of current distribution back to 1990 because mussels are 
sedentary, long-lived animals, some species attaining maximum life 
spans of 100 to 200 years (Neves and Moyer 1988, p. 185; Bauer 1992, p. 
425; Mutvei et al. 1994, p. 163-186). It was rare in the 1991-1992 
survey, and is still rare, to find juveniles of the seven mussels.
    We relied on a variety of information sources for identifying 
occupied areas in which the features essential to the conservation of 
the seven mussels may require special management considerations or 
protection, including land and water management plans of State and 
regional government agencies, surveys of stream channel condition, 
water quality assessments, and distributional information for host 
fishes. We used the sources cited in our final recovery plan's summary 
of known threats to the seven mussels to identify which essential 
features may be most vulnerable in certain portions of the occupied 
range.

Primary Constituent Elements

    In accordance with section 3(5)(A)(i) of the Act and regulations at 
50 CFR 424.12, we are required to base critical habitat determinations 
on the best scientific and commercial data available and to consider 
within areas occupied by the species at the time of listing those 
physical and biological features that are essential to the conservation 
of the species (PCEs), and that may require special management 
considerations or protection. These include, but are not limited to: 
Space for individual and population growth and for normal behavior; 
food, water, air, light, minerals, or other nutritional or 
physiological requirements; cover or shelter; sites for breeding, 
reproduction, and rearing (or development) of offspring; and habitats 
that are protected from disturbance or are representative of the 
historic geographical and ecological distributions of a species.
    The specific PCEs essential for the seven mussels are derived from 
their biological needs as described in the Background section of this 
proposal. Space for individual and population growth and normal 
behavior, and sites for reproduction and development of offspring are 
provided for the seven mussels on and within the streambed of stable 
channels with a suitable substrate, which we have captured in the PCEs 
regarding channel stability, substrate quality, and flow regime. 
Because the seven mussels are dependent on fish to complete their 
larval life stage, the PCE regarding fish hosts is a further 
requirement for successful reproduction. Various nutritional and 
physiological requirements are captured in the PCEs regarding flow 
regime and water quality. These PCEs are explained in additional detail 
below.

Channel Stability

    Unstable channels do not favor mussels in part because adults and 
juveniles are relatively sedentary animals. They are unable to move 
quickly or across great distances from unsuitable to suitable 
microhabitats on and in the stream bed. Several researchers have 
reported direct adverse effects to mussels in aggrading (filling) and 
degrading (scouring) channels (Vannote and Minshall 1982, p. 4106; 
Kanehl and Lyons 1992, p. 7; Hartfield 1993, p. 133; Brim Box and Mossa 
1999, p. 99-117). In degrading channels, mussels lose the substrate 
sediment in which they anchor themselves against the current. Mussels 
have been extirpated from streams experiencing a ``headcut'' (stream 
bed degradation progressing in an upstream direction) and from 
degrading reaches immediately downstream of dams. In aggrading channels 
or in channels with

[[Page 32754]]

actively eroding stream banks, excess sediment fouls the gills of 
mussels, which reduces feeding and respiratory efficiency, disrupts 
metabolic processes, reduces growth rates, and physically smothers 
mussels (Ellis 1936, p. 39; Stansbery and Stein 1971, p. 2178; Marking 
and Bills 1979, p. 209-210; Kat 1982, p. 123; Vannote and Minshall 
1982, p. 4105-4106; Aldridge et al. 1987, p. 18; Waters 1995, p. 173-
176; Brim Box 1999, p. 65).
    In addition to the direct effects above, channel instability 
indirectly affects mussels and their fish hosts in several ways. 
Channels becoming wider and shallower via bank erosion develop more 
extreme daily and seasonal temperature regimes, which affects DO levels 
and many other temperature-regulated physical and biological processes. 
Mussels in wider and shallower channels are likely more susceptible to 
predation. Erosive channels lose the habitat complexity provided by 
mature bankside vegetation, which reduces diversity and abundance of 
fish species. Fewer fish means lower probability of mussel recruitment 
(see ``Fish Hosts''). The many direct and indirect adverse effects of 
channel instability on mussels and their fish hosts strongly suggest 
that channel stability is a habitat feature essential to their 
conservation.

Substrate Quality

    Adult unionid mussels are generally found in localized patches 
(beds) almost completely burrowed in the substrate with only the area 
around their siphons exposed (Balfour and Smock 1995, p. 255-268). The 
composition and abundance of adult mussels have been linked to bed 
sediment distributions (Neves and Widlak 1987, p. 5; Leff et al. 1990, 
p. 415). Substrate texture (particle size distribution) affects the 
ability of mussels to burrow in the substrate and anchor themselves 
against stream currents (Lewis and Riebel 1984, p. 2025). Texture and 
other aspects of substrate composition, including bulk density (ratio 
of mass to volume), porosity (ratio of void space to volume), and 
sediment sorting may also influence mussel densities (Brim Box 1999, p. 
1-86; Brim Box and Mossa 1999, p. 99-117). Although several studies 
have reported adult habitat selection by substrate composition, most 
species are found in a relatively broad range of substrate types 
(Tevesz and McCall 1979, p. 114; Strayer 1981, p. 411; Hove and Neves 
1994, p. 36; Strayer and Ralley 1993, p. 255), with few exceptions 
(Stansbery 1966, p. 29-30). The seven mussels for which we are 
proposing critical habitat in this proposed rule are found in a variety 
of substrates, ranging from pockets of sand on bedrock to sandy mud, 
but not in substrates composed of predominantly fine materials (more 
than 50 percent silt or clay by dry weight) (Brim Box and Williams 
2000, p. 1-143; Blalock-Herod 2000, p. 1-72).
    Interstitial spaces (pores) in coarse stream substrates may become 
clogged when fine sediment input to streams is excessive (Gordon et al. 
1992, p. 1-444). Reduced pore space and pore flow rates reduce habitat 
for juvenile mussels, which tend to burrow entirely beneath the 
substrate surface, and for some adult mussels as well (Brim Box and 
Mossa 1999, p. 99-117). At least some species of juvenile unionids feed 
primarily on particles associated with sediments and pore water during 
their early development (Yeager et al. 1994, p. 221). Fine sediments 
act as vectors in delivering contaminants such as nutrients, heavy 
metals, and pesticides to streams (Salomons et al. 1987, p. 13). Most 
toxicity data for freshwater mussels is from tests with water-only 
exposures, despite reports that contaminated sediments have contributed 
to mussel declines (Newton 2003, p. 2543; Wilson et al. 1995, p. 213-
218).
    Because the juveniles and adults of the seven mussels live in 
relatively coarse and not predominantly fine-grained substrates, and 
the introduction of fine-grained sediments and various pollutants is 
likely detrimental to one or more of their life stages, we have 
determined that substrate quality is a habitat feature essential to 
their conservation.

Flow Regime

    The species that are the subject of this proposed rule are all 
riverine unionid mussels and are not found in natural or manmade ponds 
and lakes. One known exception is a single large (and presumably old) 
purple bankclimber found in Goat Rock Reservoir on the Chattahoochee 
River by malacologist C. Stringfellow (Columbus State University) in 
2000 (pers. comm. 2000). Otherwise, none of the seven mussels tolerate 
impounded conditions or persist in intermittent streams (Brim Box and 
Williams 2000, p. 1-141); therefore, continuously flowing water is a 
habitat feature associated with all potentially viable populations. 
Flowing water transports food items to the sedentary juvenile and adult 
life stages and provides oxygen for mussel respiration at depths that 
would be anoxic in a pond setting. At least three of the seven mussels 
are known to attract host fishes visually by apparently disguising 
their glochidia as potential prey items (O'Brien and Brim Box 1999, p. 
135-136; O'Brien and Williams 2002, p. 154), and some of these 
mechanisms appear to require flowing water to function effectively as 
lures. For example, flowing water is required to suspend the several-
feet-long superconglutinate of the shinyrayed pocketbook in the water 
column so that the glochidia packet at the end of it, which resembles a 
small fish, is visible to fish (O'Brien and Brim Box 1999, p. 135, 
138).
    Quantifying the amount of flowing water that is essential to the 
conservation of the seven mussels is complicated by the broad size 
range of streams they inhabit, from small tributaries near watershed 
headwaters to the Apalachicola River, which is the world's 82nd-largest 
river by discharge (Leopold 1994, p. 101). These seven mussels are 
often found near the toe of stable stream banks associated with roots 
and other instream cover or structure. A flow sufficient to inundate 
the stream bed from bank toe to bank toe with adequately oxygenated 
water deep enough to deter terrestrial predators is several orders of 
magnitude greater at a site on the lower Apalachicola River compared to 
a site on a tributary stream in the upper Ochlockonee River.
    Quantifying the amount of flowing water that is essential to the 
conservation of the seven mussels is also complicated by their 
dependency on various species of fishes to serve as hosts for their 
glochidia. Mussel population viability is likely dependent on features 
of the flow regime that influence fish host population density as well 
as features that directly affect adult and juvenile mussel survival. 
For example, the largemouth bass, which is a lab-verified host for the 
fat threeridge and shinyrayed pocketbook (O'Brien and Brim Box 1999, p. 
136; O'Brien and Williams 2002, p. 150), is known to utilize seasonally 
inundated floodplain habitats for spawning and rearing (Kilgore and 
Baker 1996, p. 291-294), habitats which do not support adult or 
juvenile mussels because they are dry for several months of most years. 
Year class strength of largemouth bass has been positively correlated 
with flows in several river systems due to the additional habitat 
available in high-flow years (Raibley et al. 1997, p. 852-853), and 
fish host density is a factor in mussel recruitment (see ``Fish Hosts'' 
discussion below). Year class strength is abundance of a cohort (born 
in a particular year) relative to other cohorts. A strong year class is 
represented in much greater numbers than a weak year class, presumably 
because the strong

[[Page 32755]]

year class experienced more favorable conditions for recruitment.
    Riverine ecologists have recognized that variable flow creates 
variable physical and chemical conditions that limit the distribution 
and abundance of riverine species (Power et al. 1995, p. 166; Resh et 
al. 1988, p. 443). Altering natural long-term patterns of flow changes 
the structure, composition, and function of riverine communities (Bain 
et al. 1988, p. 382-392; Hill et al. 1991, p. 198-210; Sparks 1995, p. 
172-173; Scheidegger and Bain 1995, p. 134). Poff et al. (1997, p. 770) 
and Richter et al. (1997b, p. 243) concluded that the accumulated 
research on the relationship between hydrologic variability and 
riverine ecological integrity overwhelmingly supported a ``natural flow 
paradigm,'' that is, the patterns of variability in a river's natural 
flow regime are critical in sustaining its ecological integrity. 
Richter et al. (1996, p. 1165, 1997b, p. 236) proposed a set of 
parameters collectively termed ``indicators of hydrologic alteration'' 
(IHA) for characterizing ecologically relevant features of a flow 
regime.
    The Service and USEPA adapted a subset of the IHA parameters as 
instream flow guidelines for protecting riverine ecosystems under a 
possible interstate water allocation formula between Alabama, Florida, 
and Georgia for the ACF Basin (USFWS and USEPA 1999, p. 1). Although 
the three States failed to agree upon an allocation formula and the ACF 
Compact authorizing their negotiations expired, the Service has applied 
the instream flow guidelines in consultations with Federal agencies on 
actions affecting the species addressed in this proposed rule. The 
Service-USEPA guidelines are definitions of measures of flow magnitude, 
duration, frequency, and seasonality that may serve as thresholds for 
``may affect'' determinations for proposed Federal actions that would 
alter a flow regime (for example, water withdrawals and dam 
operations). The thresholds are computed from long-term flow records 
appropriate to the proposed action, such as daily flow records from a 
stream gage in the action area. The Service-USEPA guidelines are 
designed as a tool for site-specific analyses and such efforts as this 
proposed rule.

Water Quality

    The ranges of several standard physical and chemical water quality 
parameters (such as temperature, DO, pH, conductivity) that define 
suitable habitat conditions for the seven mussels have not been 
specifically investigated. As sedentary animals, mussels must tolerate 
the full range of these parameters to persist in that stream. 
Quantifying water quality tolerances for the seven mussels is further 
complicated by the dependency of mussels on fish hosts, which may 
exhibit different tolerances.
    Most mussels are considered sensitive to low DO levels and high 
temperatures (Fuller 1974, p. 245). Johnson (2001, p. 8-11) monitored 
water quality and mussel mortality during a drought year in the lower 
Flint River Basin. Low DO levels, which occurred during low flow 
periods, were associated with high weekly mussel mortality. Species-
specific mortality varied considerably. The shinyrayed pocketbook and 
Gulf moccasinshell were among the species with the highest mortality 
rates when exposed to DO concentrations less than 5 milligrams per 
liter (mg/L). The oval pigtoe demonstrated moderate, but significantly 
higher than average, mortality when DO was less than 5 mg/L.
    Juvenile mussels may spend their first few years buried in the 
sediments of the stream bed. Interstitial water (pore water) in 
sediments is generally less oxygenated than flowing water in the stream 
above (Sparks and Strayer 1998, p. 129). Sparks and Strayer (1998, p. 
132) observed marked differences in behavior between juvenile Eastern 
elliptio (Elliptio complanata), congener of the Chipola slabshell, that 
were exposed to DO levels of 2 mg/L and 4 mg/L, and most juveniles of 
this species that were exposed to 1.3 mg/L for a week died. In general, 
juveniles are sensitive to low DO levels. Interstitial DO levels in 
streams of the eastern United States are usually less than 4 mg/L in 
the summer and may fall below 1 mg/L (Sparks and Strayer 1998, p. 132).
    Water temperature affects the amount of oxygen that can be 
dissolved in water and the toxicity of various pollutants. The toxic 
effects of ammonia are more pronounced at higher temperatures and at 
higher pH (Mummert et al. 2003, p. 2545, 2550; Newton 2003, p. 2543). 
High temperatures or decreasing pH may increase the toxicity of metals 
to unionids (Havlik and Marking 1987, p. 14). Watters and O'Dee (2000, 
p. 136) suggested that the release of glochidia is regulated by water 
temperature. In Texas, exceptionally warm temperatures appeared to 
prompt early initiation of mussel reproductive activity, and cool 
temperatures appeared to delay activity (Howells 2000, p. 40). 
Temperature may affect immune system response in fish. Some fish 
species that reject infections by mussel glochidia at higher 
temperatures are infected at lower temperatures (Roberts and Barnhart 
1999, p. 484).
    Various contaminants in point- and non-point-source discharges can 
degrade water and substrate quality and adversely affect mussel 
populations (Horne and McIntosh 1979, p. 119-133; Neves and Zale 1982, 
p. 53; McCann and Neves 1992, p. 77-81; Havlik and Marking 1987, p. 1-
20). Naimo (1995, p. 341) suggested that chronic, low-level 
contamination of streams may explain the widespread decreases in mussel 
density and diversity. Mussels appear to be among the organisms most 
sensitive to heavy metals (Keller and Zam 1991, p. 539), several of 
which are lethal at relatively low levels (Havlik and Marking 1987, p. 
3). Cadmium appears to be the most toxic (Havlik and Marking 1987, p. 
3), although copper, mercury, chromium, and zinc may also impair 
physiological processes (Jacobson et al. 1993, p. 879; Naimo 1995, p. 
353-355; Keller and Zam 1991, p. 539-546; Keller and Lydy 1997, p. 3). 
Metals stored in mussel tissues indicate recent or current exposure 
(Havlik and Marking 1987, p. 12), while concentrations in shell 
material indicate past exposure (Imlay 1982, p. 7; Mutvei et al. 1994, 
p. 163-186). Highly acidic pollutants such as metals may contribute to 
mussel mortality by dissolving shells (Stansbery 1995, p. 2-3). Low 
levels of some metals may inhibit glochidial attachment (Huebner and 
Pynn[ouml]nen 1992, p. 2349). Mussel recruitment may be reduced in 
habitats with low but chronic heavy metal and other toxicant inputs 
(Yeager et al. 1994, p. 221; Naimo 1995, p. 341; Ahlstedt and 
Tuberville 1997, p. 72-77).
    Water pollutants associated with agricultural activity may 
adversely affect mussels. Arsenic trioxide, which is used in the 
poultry industry as a feed additive, is lethal to adult mussels at 
concentrations of 16.0 parts per million (ppm), and ammonia is lethal 
at concentrations of 5.0 ppm (Havlik and Marking 1987, p. 3, 13). 
Ammonia is associated with animal feedlots, nitrogenous fertilizers, 
and the effluents of older municipal wastewater treatment plants. 
Ammonia causes a shift in glucose metabolism (Chetty and Indira 1995, 
p. 84) and alters the utilization of lipids, phospholipids, and 
cholesterol (Chetty and Indira 1994, p. 693). Stream ecosystems are 
altered when nutrients are added at concentrations that cannot be 
assimilated (Stansbery 1995, p. 2-3). Excessive nutrients promote the 
growth of filamentous algae in streams, which may render substrates 
unsuitable for mussels of all life stages and degrade water quality by 
consuming oxygen during night-time respiration and

[[Page 32756]]

during decay to levels that mussels cannot tolerate. Several studies 
have described adverse effects of pesticides on mussels (Fuller 1974, 
p. 215-257; Havlik and Marking 1987, p. 13; Moulton et al. 1996, p. 
131). Commonly used pesticides were cited as the likely cause of a 
mussel die-off in a North Carolina stream (Fleming et al. 1995, p. 877-
879).
    Gourdreau et al. (1993, p. 211-230) examined mussel populations 
relative to the discharges of two municipal wastewater treatment plants 
on the Clinch River in Tazewell County, Virginia. Mussels were absent 
or present in low numbers immediately downstream of these discharges, 
but occurred in greater diversity and abundance immediately upstream 
and farther downstream. The investigators hypothesized that, in 
addition to chemicals of known toxicity to glochidia, the bacteria and 
protozoans associated with wastewater discharges may also adversely 
affect mussel reproduction. Glochidia are vulnerable to attack by 
bacteria and protozoans before and after they are released from the 
adult female mussel (Fuller 1974, p. 219; Goudreau et al. 1993, p. 
221).
    Adults of some mussel species may tolerate short-term exposure to 
various contaminants by closing their valves (Keller 1993, p. 701). 
Juveniles and glochidia appear more sensitive than adults to heavy 
metals (McCann and Neves, 1992, p. 77-81) and to ammonia (Goudreau et 
al. 1993, p. 224). Ammonia is lethal to juveniles at concentrations as 
low as 0.7 ppm total ammonia nitrogen, normalized to pH 8, and lethal 
to glochidia at concentrations as low as 2.4 ppm (Augspurger et al. 
2003, p. 2569-2575). In streams, ammonia may occur at highest 
concentrations in substrate interstitial spaces where juvenile mussels 
live and feed (Whiteman et al 1996, p. 794; Hickey and Martin 1999, p. 
38; Augspurger et al. 2003, p. 2569-2575).
    In general, we believe the numeric standards for pollutants and 
water quality parameters (for example, heavy metals and DO) that are 
adopted by the States under the Federal Clean Water Act (CWA) represent 
levels that are essential to the conservation of the seven mussels. 
However, some State standards may not adequately protect mussels, such 
as the standard for ammonia (Augspurger et al. 2003, p. 2571; Newton et 
al. 2003, p. 2559). USEPA and FWS and National Marine Fisheries Service 
(the Services) agreed to a national consultation on the CWA Section 
304(a) aquatic life criteria as part of a Memorandum of Agreement 
regarding interagency coordination under the CWA and the Act (66 FR 
11202, February 22, 2001). The criteria for some pollutants, such as 
ammonia, are presently under review. Although the State standards 
adopted consistent with the USEPA criteria generally represent levels 
that are safe for the seven mussels, these standards are sometimes 
violated in some streams within their current range. Rather than 
specify the ranges of dozens of water quality parameters for the seven 
mussels, it is more practical to deal with cases where the national 
criteria are not protective of these and other listed species under the 
national consultations with USEPA. For purposes of this proposed rule, 
the evidence for the dependency of the seven mussels on good water 
quality supports identifying water quality generally as a habitat 
feature that is essential to their conservation.

Fish Hosts

    Most unionid mussels, including the seven species, parasitize fish 
during the larval life stage (see ``Background''), depending on fish 
hosts not only for the physiological transformation from larval to 
juvenile form (Isom and Hudson 1982, p. 147-151), but also for spatial 
dispersal (Neves 1993, p. 4). The distribution and diversity of 
unionids is strongly related to the distribution and diversity of fish 
species (Watters 1992, p. 488; Haag and Warren 1998, p. 298). Bogan 
(1993, p. 600) identified the dependency of mussels on fish hosts, 
which are affected by exploitation and a variety of common habitat 
alterations, as one of several contributing causes in the extinction of 
several unionid species worldwide. Haag and Warren (1998, p. 303) 
identified host fish availability and density as significant factors 
influencing where certain mussel populations can persist.
    Although female mussels may produce 75,000 to 3.5 million glochidia 
(Surber 1912, p. 3-10; Coker et al. 1921, p. 144; Yeager and Neves 
1986, p. 333), contact of the glochidia with a suitable host fish is a 
low-probability event (Neves et al. 1997, p. 60). Contact is dependent 
on many factors, including the timely presence of the host fish, the 
feeding and respiratory behaviors of the fish (Dartnall and Walkey 
1979, p. 36; Neves et al. 1985, p. 17-18), and for some species, the 
behavior of the mussel when the fish is present (Davenport and Warmuth 
1965, p. R77; Kraemer 1970, p. 225-282). Contact between glochidia and 
host fish does not ensure successful larval development to the juvenile 
form, because some fish species have natural immunity to glochidial 
infestation and others acquire immunity following infestation (Watters 
and O'Dee 1996, p. 387). Glochidia that contact a host with natural 
immunity are rejected and die, usually within 11 days (Neves et al. 
1985, p. 15, 17; Yeager and Neves 1986, p. 338; Waller and Mitchell 
1989, p. 86). In the case of acquired immunity, glochidia experience 
decreased transformation rates with subsequent infections of an 
initially suitable host fish (Arey 1932, p. 372; Bauer and Vogel 1987, 
p. 393; Luo 1993, p. 26). The number of exposures associated with 
glochidial sloughing is variable (Watters and O'Dee 1996, p. 385, 387).
    As few as 1 to as many as 25 fish species are known to serve as 
suitable hosts for particular species of mussels (Fuller 1974, p. 238; 
Trdan and Hoeh 1982, p. 386; Gordon and Layzer 1989, p. 1-98; Hoggarth 
1992, p. 3). Some mussels are host-fish specialists that parasitize a 
few fish species (Zale and Neves 1982, p. 2540; Yeager and Saylor 1995, 
p. 4; Neves et al. 1985, p. 13, 17), and others are generalists that 
parasitize a great variety of host fishes (Trdan and Hoeh 1982, p. 
386). Generally, mussels that are known host-fish specialists tend to 
release glochidia in conglutinates (multiple glochidia in a packet 
versus a stream of single glochidia) or use various means of attracting 
a fish host before releasing multiple glochidia (Watters 1997, p. 45). 
Because fish that are not naturally immune to glochidial infection 
develop some immunity after infection, securing a host fish is to some 
degree a ``first come, first served'' situation. Some researchers have 
hypothesized that mussels may compete for fish hosts (Watters 1997, p. 
57; Trdan and Hoeh 1982, p. 384-385).
    Watters (1997, p. 45-62) developed individual-based models of 
mussel--fish interactions to simulate unionid reproductive strategies, 
showing specialists tended to have lower population sizes and were less 
sensitive to fluctuating host fish density than generalists, which 
attained much higher population sizes when host fish density was high 
and declined when host fishdensity declined.
    Haag and Warren (1998, p. 297-306) examined patterns of fish and 
mussel community composition in two north Alabama drainages. They found 
that densities of host-generalist mussels and of host-specialist 
mussels with elaborate host-attracting mechanisms were independent of 
host-fish densities, and were present throughout the two drainages. 
Densities of host-specialist mussels without elaborate host-attracting 
mechanisms were positively correlated with host-fish densities and were 
absent or rare near the drainages' headwaters.

[[Page 32757]]

    Host-fish specificity has been examined in laboratory tests for 
five of the seven mussels: the fat threeridge, Gulf moccasinshell, oval 
pigtoe, purple bankclimber (O'Brien and Williams 2002, p. 151), and 
shiny-rayed pocketbook (O'Brien and Brim Box 1999, 136). The fat 
threeridge lacks mantle modifications or other morphological 
specializations that would serve to attract host fishes and appears to 
be a host-fish generalist that may infect fishes of at least three 
different fish families. Glochidia transformed to juveniles under 
laboratory conditions on five of seven fish species tested: Weed shiner 
(Notropis texanus), bluegill (Lepomis macrochirus), redear sunfish (L. 
microlophus), largemouth bass (Micropterus salmoides), and blackbanded 
darter (Percina nigrofasciata) (O'Brien and Williams 2002, p. 152).
    The elaborate superconglutinate of the shiny-rayed pocketbook (see 
``Background'') suggests it is a host-fish specialist that targets 
sight-feeding piscivorous fishes, such as bass. O'Brien and Brim Box 
(1999, p. 136) confirmed that largemouth bass and spotted bass 
(Micropterus punctulatus) are likely primary hosts (all fishes infected 
produced juvenile mussels) among 11 species tested. Low transformation 
rates were associated with fish such as the eastern mosquitofish 
(Gambusia holbrooki) and bluegill.
    The Gulf moccasinshell is probably a host-fish specialist that 
primarily parasitizes darters. It visually lures host fish by 
undulating its dark mantle flaps against swollen white gills (O'Brien 
and Williams 2002, p. 154). O'Brien and Williams (2002, p. 152) lab-
tested eight fish species for suitability as hosts, finding that all 
black-banded darters and brown darters (Etheostoma edwini) exposed to 
infection transformed glochidia to juveniles. Other fishes, including 
the eastern mosquitofish, also transformed glochidia, but at lower 
percentage rates.
    The extreme rarity of the Ochlockonee moccasinshell has precluded 
any opportunities to explore its life history. We assume its 
reproductive biology is similar to its congener, the Gulf 
moccasinshell, which uses darters as host fish.
    The oval pigtoe releases rigid white to pinkish conglutinates, 
which passively drift in the current and may resemble the food 
organisms of small-bodied fishes. O'Brien and Williams (2002, p. 152) 
tested 11 fish species as hosts, finding that glochidia transformed on 
the gills of fish such as the sailfin shiner (Pteronotropis 
hypselopterus) and eastern mosquitofish. They considered only the 
sailfin shiner as a primary host, as it was the only species upon which 
the transformation rate exceeded 50 percent.
    We are aware of no studies of the reproductive biology of the 
Chipola slabshell. It is likely that the species expels glochidia in a 
conglutinate, as do several other members of the genus Elliptio that 
occur in the ACF Basin (Brim Box and Williams 2000, p. 34-47). Keller 
and Ruessler (1997, p. 402-407) identified centrarchids (sunfishes) as 
host fishes of other southeastern Elliptio.
    O'Brien and Williams (2002, p. 153) observed in the laboratory that 
purple bankclimber conglutinates readily disintegrated when they 
contained mature glochidia, and these were easily suspended in the 
water by the aerators in their holding tanks. They speculated that the 
species may rely on stream currents to carry glochidia to host fish, 
which is typical of host-fish generalist species. Of the 14 fish 
species they tested as potential hosts, only a few species transformed 
glochidia, including the eastern mosquitofish and blackbanded darter. 
Only the mosquito fish was 100 percent effective (all fish tested 
transformed glochidia), but it is an unlikely primary host fish. The 
mosquito fish occupies backwater areas and stream margins with little 
or no current (Lee et al. 1980, p. 1-854), while the bankclimber is 
found mostly in the main channels of larger streams and rivers. The 
primary host fishes of the purple bankclimber are still unknown.
    Data that might suggest densities of the various primary host fish 
species named above that are sufficient to support normal mussel 
recruitment and dispersal rates are not available. Stochastic 
simulations of fish'mussel interactions indicate that mussel 
populations are extirpated if a threshold host fish density is not 
exceeded (Watters 1997, p. 60). Further studies of fish and mussel 
population dynamics are necessary to quantify species-specific 
thresholds; however, we recognize that the presence of host fish is a 
biological habitat feature essential to the conservation of the seven 
mussels.

Primary Constituent Elements for Five Endangered and Two Threatened 
Mussels

    Based on our current knowledge of the life history, biology, and 
ecology of the seven mussels, and of the habitat features necessary to 
support their essential life history functions in areas occupied at the 
time of listing, summarized above, we have determined that the PCEs 
are:
    (1) A geomorphically stable stream channel (a channel that 
maintains its lateral dimensions, longitudinal profile, and spatial 
pattern over time without an aggrading or degrading bed elevation);
    (2) A predominantly sand, gravel, and/or cobble stream substrate;
    (3) Permanently flowing water;
    (4) Water quality (including temperature, turbidity, dissolved 
oxygen, and chemical constituents) that meets or exceeds the current 
aquatic life criteria established under the Clean Water Act (33 U.S.C. 
1251-1387); and
    (5) Fish hosts (such as largemouth bass, sailfin shiner, brown 
darter) that support the larval life stages of the seven mussels.

Criteria Used To Identify Critical Habitat

    We are proposing to designate as critical habitat areas that were 
occupied at the time of listing by one or more of the seven mussels and 
that contain one or more of the PCEs to support life history functions 
essential to the conservation of the species. This section describes 
how we identified those streams and delineated the upstream and 
downstream boundaries of 11 proposed critical habitat units.
    We began our analysis by examining the full extent of each species' 
historical and current range. As discussed under ``Summary of Threats 
to Surviving Populations'' above, the declining range and abundance of 
the seven mussels is due mostly to changes in their riverine habitats 
resulting from dams, dredging, mining, channelization, pollution, 
sedimentation, and water withdrawals. The Econfina, ACF, Ochlockonee, 
and Suwannee drainages contain about 54,000 km (33,500 mi) of perennial 
streams (USGS 1:100,000 National Hydrography Data). From mussel survey 
records, the historical range of the seven mussels collectively spanned 
about 3,300 km (2,050 mi), or 6 percent, of the river and stream 
channels in these drainages, but no one species accounts for more than 
about 2,300 km (1,445 mi) of that total (USFWS 2003, p. 78-80). We 
estimate that the five species listed as endangered are each extirpated 
from over half of their historical range, and the two threatened 
species are extirpated from about one-third of theirs, but none are 
extirpated entirely from the four major drainages in which they each 
occurred historically. All seven mussels were more widespread and more 
abundant within each of the four drainages historically.
    The largest single portion of the historical range lost to the 
seven mussels is the mainstem of the Chattahoochee River. The

[[Page 32758]]

Chattahoochee comprised over 700 km (435 mi), or almost one-quarter, of 
the 3,300-km (2,050-mi) collective historical range, and supported the 
shinyrayed pocketbook, Gulf moccasinshell, oval pigtoe, and purple 
bankclimber. It is now impounded by several major dams for much of its 
length and no longer supports the listed mussels. With the exception of 
a single live animal found in Goat Rock Reservoir in 2000, the purple 
bankclimber appears extirpated from the entire Chattahoochee Basin, but 
at least one of the other three species persist in three of its 
tributaries: Uchee Creek, Sawhatchee Creek, and Kirkland Creek. 
Elsewhere in the four major drainages, the pattern of extirpation is 
more variable, with one or more of the seven species persisting in 
portions of a drainage where others have disappeared. The collective 
range of the seven species now spans about 1,900 km (1,180 mi) of river 
and stream channels. Within this collective range, the species 
presently occur in as little as 55 km (34 mi) (the Ochlockonee 
moccasinshell) to as much as 785 km (488 mi) (the shinyrayed 
pocketbook) (USFWS 2003, p. 78-80).
    To identify the specific areas that were occupied at the time of 
listing by each of the seven mussels and that contain one or more of 
the PCEs, we used post-1990 mussel survey results. Because mussels are 
sedentary and long-lived animals, occupancy is strong evidence that 
some or all of the PCEs are present, except where it is apparent that 
one or a few adult individuals remain at a location with little or no 
possibility of reproducing due to substantial habitat alteration (such 
as the single purple bankclimber found in Goat Rock Reservoir). It is 
not feasible to survey all potential habitat for the seven species; 
therefore, to delineate a species' occupied range in the larger stream 
network, it is necessary to extrapolate from the available survey data. 
Most of the tributary streams in the four basins that may support one 
or more of the seven species have never been surveyed, and we do not 
propose any unsurveyed streams as critical habitat. We used USGS 
1:100,000 digital stream maps to delineate the probable upstream and 
downstream limits to the seven species' distribution in streams 
surveyed since 1990, according to the criteria listed below. These 
limits form the boundaries of proposed critical habitat units as 
explained below.
    (a) The lateral boundaries of a unit are the ordinary high-water 
marks on each bank of currently occupied streams. We recognize the 
dynamic nature of riverine systems and that floodplains and riparian 
areas are integral parts of those systems. Processes that occur and 
habitat characteristics that are found outside the stream banks are 
important in maintaining channel morphology, providing energy and 
nutrients, and protecting the instream environment from pollutants and 
excessive sediments. Similarly, floodplain and backwater habitats may 
be important in the life cycle of fish that serve as hosts for mussel 
larvae. Although factors affecting the PCEs may occur outside the 
channel, the PCEs themselves occur within the channel.
    (b) The upstream boundary of a unit in an occupied stream is the 
first perennial tributary confluence or first permanent barrier to fish 
passage (such as a dam) upstream of the upstream-most current 
occurrence record. Many of the mussel survey sites are located near 
watershed headwaters. In these areas, the confluence of a tributary 
typically marks a significant change in the size of the stream and is a 
logical and recognizable upstream boundary for habitat conditions that 
are similar to the upstream-most occurrence record. Likewise, a dam or 
other barrier to fish passage marks the upstream extent to which 
mussels at the upstream-most occurrence may disperse via their fish 
hosts. Therefore, proposed segments encapsulate habitat containing 
essential features used by host fish and the seven mussels for 
successful natural reproductive process. Habitat above these boundaries 
does not contain features essential to the conservation of the species.
    (c) The downstream boundary of a unit in an occupied stream is the 
mouth of the stream, the upstream extent of tidal influence, or the 
upstream extent of an impoundment, whichever comes first, downstream of 
the downstream-most occurrence record. Many survey sites are located 
near the mouths of streams, the upstream extent of impoundments, or the 
upstream extent of tidal influence. Survey locations are typically at 
road crossings, because that is where surveyors can most easily gain 
access to the stream. These road crossings do not typically represent a 
meaningful ecological boundary for longitudinal stream habitat 
conditions. Mussels are dispersed via host fish, and because these host 
fish traverse freely in the area between the upstream most occurrence 
and any existing downstream restriction to fish passage, larvae drop 
off their host fish at random points along the stream flow segments 
traversed by fish. Further, the sperm of all seven species and the 
conglutinates (glochidia packets) of some of the seven may be carried 
downstream by currents and are viable for several hours to several days 
unless they reach unsuitable habitat conditions, such as intolerable 
salinity or still water, in which either would sink to the bottom and 
be smothered in the sediments. Therefore, we are proposing stream 
segments that have mussel point locations from the upstream limit as 
defined in (b) above to the downstream location where the PCEs are no 
longer present.
    The application of these criteria resulted in the identification of 
11 units occupied by one or more of the seven mussels and that contain 
one or more of the PCEs as indicated by the presence and persistence of 
one or more of the listed mussels (see ``Proposed Critical Habitat 
Designation''). Based on fish distributional records (Lee et al. 1980, 
p. 1-854) and our experience sampling fish in these drainages, these 
areas also support shiners, darters, and other fishes that have been 
identified as hosts or potential hosts for one or more of the seven 
mussels. Further, on the basis of a review of the information 
available, we have determined that areas not currently known to be 
occupied by the seven mussels do not appear to be essential to their 
conservation. As such, we have not included any areas not known to be 
occupied by these mussel species in this proposed designation.
    When determining the boundaries of proposed critical habitat for 
the seven mussels, we made every effort to avoid manmade structures 
existing on the effective date of this rule and not containing one or 
more of the primary constituent elements, such as buildings and roads. 
Any such structures inadvertently left inside the critical habitat 
boundaries have been excluded by the text in this proposed rule and are 
not proposed for designation.

Special Management Considerations or Protection

    When designating critical habitat, we assess whether the areas 
determined to be occupied at the time of listing and containing the 
PCEs may require special management considerations or protections. 
Activities in or adjacent to each of the critical habitat units 
described in this proposed rule may affect one or more of the PCEs that 
are found in the unit. These activities include, but are not limited 
to, those listed in the Adverse Modification Standard section as 
activities that may destroy or adversely modify critical habitat. We 
find that the features essential to each of the seven mussel species 
contained within the areas proposed for designation may require special 
management considerations or protections due to known or probable

[[Page 32759]]

threats from these activities. We summarize here the nature of the 
threats and the resulting conservation needs for both the mussels and 
their host fish across the range of the seven mussels.
    Sedimentation is an almost ubiquitous threat in the range of the 
seven mussels. A wide variety of activities, such as livestock grazing, 
road and bridge construction, clear-cut logging, and off-road vehicle 
use, that are common in all 11 units may increase erosion rates, either 
in the banks of the stream channel itself or elsewhere in the 
watershed, and cause the accumulation of fine sediments on the stream 
bed. Management considerations to deal with this threat include 
protecting streams from sedimentation through application of 
agricultural and forestry best management practices, avoiding soil- and 
vegetation-disturbing activity in the riparian zone, restoring unstable 
stream channels and other erosive areas, and other practices that 
prevent or reduce erosion.
    Urbanization, road and bridge construction, and other large-scale 
alterations of land cover that substantially alter the runoff 
characteristics of the watershed may threaten channel stability in 
units near the major urban areas of Dothan, Alabama (unit 2); Panama 
City and Tallahassee, Florida (units 1 and 10); Albany, Atlanta, and 
Columbus, Georgia (units 3, 5, 6, and 7); and other cities. Management 
considerations to deal with the threat of channel instability include 
avoiding soil- and vegetation-disturbing activity in the riparian zone, 
limiting impervious surface area, and other urban storm water runoff 
control methods. Sand and gravel mining (unit 3), dredging and 
channelization (unit 8), and dam construction (unit 5) may also affect 
channel stability.
    The construction and operation of dams, water withdrawals, and 
water diversions may alter features of the flow regime important to the 
mussels and their host fishes. This threat is present to some degree in 
all 11 proposed units, but is greatest in units 5, 6, 7, 8, and 10, 
which are downstream of the major mainstem dams or in areas of 
relatively high municipal, industrial, or agricultural water use. 
Measures to deal with this threat include water conservation and 
operational strategies that manage water storage capacity and water 
demands in combination to minimize departures from the natural flow 
regime.
    Water pollution, especially from non-point (dispersed release) 
sources, is another almost ubiquitous threat in all 11 units. Water 
quality is reported as impaired or potentially impaired in some 
portions of all four river basins within the current range of the seven 
mussels, according to the water quality agencies of the three States in 
their periodic assessments under Section 305(b) of the Clean Water Act 
(CWA) (see ``Summary of Threats to Surviving Populations''). Streams 
that receive a high proportion of their flow from the discharge of 
springs are vulnerable to nutrient enrichment from fertilizers and to 
other pollutants applied in the recharge areas of those springs (units 
1, 2, and 7), which may extend far from the streams themselves. 
Management considerations to deal with the threat of pollution include 
applying agricultural and forestry best management practices, 
preserving native vegetation in riparian zones, maintaining septic 
systems, and taking other measures to minimize pollutant-laden runoff 
to streams.

Proposed Critical Habitat Designation

    We are proposing 11 groups of river and stream segments (units) as 
critical habitat for the seven mussels. The river and stream segments 
comprising each unit are contiguous to allow for the movement of fish 
hosts dispersing the larval life stages of the seven mussels within the 
unit. Barriers to the movement of fish hosts (dams and salt water) 
separate the units from each other. The critical habitat units 
described below constitute our best assessment at this time of areas 
that were occupied by one or more of the seven mussels at the time of 
listing (1998) and which contain the physical and biological features 
essential to the each of the mussel species. Each unit is designated 
only for those species that currently occupy it. Each unit contains one 
or more of the PCEs, and may require special management considerations 
or protection to address the threats noted above. The 11 units, and the 
States in which they occur, are: (1) Econfina Creek (FL), (2) Chipola 
River (AL, FL), (3) Uchee Creek (AL), (4) Sawhatchee Creek and Kirkland 
Creek (GA), (5) Upper Flint River (GA), (6) Middle Flint River (GA), 
(7) Lower Flint River (GA), (8) Apalachicola River (FL), (9) Upper 
Ochlockonee River (FL, GA), (10) Lower Ochlockonee River (FL), and (11) 
Santa Fe River and New River (FL). Collectively, the total length of 
the river and stream segments of all of the areas (units) proposed is 
approximately 1,864 km (1,158 mi). Table 1 shows the approximate length 
of rivers and streams proposed as occupied critical habitat for each of 
the seven mussels in the 11 units.

------------------------------------------------------------------------
                                                Currently occupied
   Species, critical habitat unit, and   -------------------------------
                state(s)                    Kilometers         Miles
------------------------------------------------------------------------
             Fat threeridge
2. Chipola River, AL, FL................           190.0           118.1
8. Apalachicola River, FL...............           155.4            96.6
                                         -------------------------------
    Total...............................           345.4           214.7
------------------------------------------------------------------------
          Shinyrayed pocketbook
2. Chipola River, AL, FL................           190.0           118.1
3. Uchee Creek, AL......................            34.2            21.2
4. Sawhatchee Creek and Kirkland Creek,             37.8            23.5
 GA.....................................
5. Upper Flint River, GA................           380.4           236.4
6. Middle Flint River, GA...............           302.3           187.8
7. Lower Flint River, GA................           396.7           246.5
9. Upper Ochlockonee River, FL, GA......           177.3           110.2
                                         -------------------------------
    Total...............................          1518.7           943.7
------------------------------------------------------------------------
           Gulf moccasinshell
1. Econfina Creek, FL...................            31.4            19.5
2. Chipola River, AL, FL................           190.0           118.1

[[Page 32760]]

 
4. Sawhatchee Creek and Kirkland Creek,             37.8            23.5
 GA.....................................
5. Upper Flint River, GA................           380.4           236.4
6. Middle Flint River, GA...............           302.3           187.8
7. Lower Flint River, GA................           396.7           246.5
                                         -------------------------------
    Total...............................          1338.3           831.8
------------------------------------------------------------------------
        Ochlockonee moccasinshell
9. Upper Ochlockonee River, FL, GA......           177.3           110.2
                                         -------------------------------
    Total...............................           177.3           110.2
------------------------------------------------------------------------
               Oval pigtoe
1. Econfina Creek, FL...................            31.4            19.5
2. Chipola River, AL, FL................           190.0           118.1
4. Sawhatchee Creek and Kirkland Creek,             37.8            23.5
 GA.....................................
5. Upper Flint River, GA................           380.4           236.4
6. Middle Flint River, GA...............           302.3           187.8
7. Lower Flint River, GA................           396.7           246.5
9. Upper Ochlockonee River, FL, GA......           177.3           110.2
11. Santa Fe and New Rivers, FL.........            83.1            51.6
                                         -------------------------------
    Total...............................          1598.7           993.6
------------------------------------------------------------------------
            Chipola slabshell
2. Chipola River, AL, FL................           190.0           118.1
                                         -------------------------------
    Total...............................           190.0           118.1
------------------------------------------------------------------------
           Purple bankclimber
5. Upper Flint River, GA................           380.4           236.4
6. Middle Flint River, GA...............           302.3           187.8
7. Lower Flint River, GA................           396.7           246.5
8. Apalachicola River, FL...............           155.4            96.6
9. Upper Ochlockonee River, FL, GA......           177.3           110.2
10. Lower Ochlockonee River, FL.........            75.4            46.9
                                         -------------------------------
    Total...............................          1487.2           924.4
ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½
        Total Proposed for All 11 Units           1864.0          1158.3
         (All Species)..................
------------------------------------------------------------------------

    Brief descriptions of each unit follow, listing the rivers and 
streams included, the upstream and downstream extent of the unit in 
those rivers and streams, and which of the seven mussels were present 
at the time of listing. Each critical habitat unit includes the 
channels of the rivers and streams listed between the ordinary high 
water mark on each bank, which is defined in 33 CFR 329.11 as ``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.'' In the unit descriptions, distances between 
landmarks marking the upstream or downstream extent of a particular 
stream in the unit are given in kilometers (km) and equivalent miles 
(mi), as measured tracing the course of the stream, not straight-line 
distance.

Unit 1: Econfina Creek, Florida

    Unit 1 includes the main stem of Econfina Creek and one of its 
tributaries in Bay and Washington counties, Florida, encompassing a 
total stream length of 31.4 km (19.5 mi). The main stem of Econfina 
Creek as proposed extends from its confluence with Deer Point Lake at 
the powerline crossing located 3.8 km (2.3 miles) downstream of Bay 
County Highway 388, Bay County, Florida, upstream 28.6 km (17.8 mi) to 
Tenmile Creek in Washington County, Florida. Unit 1 also includes the 
tributary stream Moccasin Creek from its confluence with Econfina Creek 
upstream 2.8 km (1.7 mi) to Ellis Branch in Bay County. Unit 1 is 
designated for the Gulf moccasinshell and oval pigtoe (Blalock-Herod 
unpub. data 2002-03; Brim Box unpub. data 1996; Williams unpub. data 
1993).

Unit 2: Chipola River, Alabama and Florida

    Unit 2 includes the main stem of the Chipola River (including the 
reach known as Dead Lake) and six of its tributaries, encompassing a 
total stream length of 190.0 km (118.1 mi) in Houston County, Alabama; 
and in Calhoun, Gulf, and Jackson counties, Florida. The main stem of 
the Chipola River as proposed extends from its confluence with the 
Apalachicola River in Gulf County, Florida, upstream 144.9 km (90.0 mi) 
to the confluence of Marshall and Cowarts creeks in Jackson County, 
Florida. A short segment of the Chipola River that flows underground 
within the boundaries of Florida Caverns State Park in Jackson County, 
Florida, is not included in Unit 2. The downstream extent of each 
tributary within the unit is its mouth (its confluence with the water 
body named), and the upstream extent is the landmark listed. The 
tributaries of the Chipola River included in Unit 2 are: Dry Creek,

[[Page 32761]]

from the Chipola River upstream 7.6 km (4.7 mi) to Ditch Branch in 
Jackson County, Florida; Rocky Creek, from the Chipola River upstream 
7.1 km (4.4 mi) to Little Rocky Creek in Jackson County, Florida; 
Waddells Mill Creek, from the Chipola River upstream 3.7 km (2.3 mi) to 
Russ Mill Creek in Jackson County, Florida; Baker Creek, from Waddells 
Mill Creek upstream 5.3 km (3.3 mi) to the confluence with Tanner 
Springs in Jackson County, Florida; Marshall Creek, from the Chipola 
River upstream 13.7 km (8.5 mi) to the Alabama-Florida State line in 
Jackson County, Florida (this creek is known as Big Creek in Alabama); 
and Big Creek, from the Alabama-Florida State line upstream 7.8 km (4.9 
mi) to Double Bridges Creek in Houston County, Alabama.
    This unit is designated for the fat threeridge (Brim Box and 
Williams 2000, p. 92-93; Miller 1998, p. 54), shinyrayed pocketbook 
(Williams unpub. data 2002; Brim Box and Williams 2000, p. 109-110; 
Smith unpub. data 2001; Blalock-Herod unpub. data 2000, 2003; Butler 
unpub. data 1993, 1994, 1999, 2000); Gulf moccasinshell (Butler unpub. 
data 1999, 2002; Brim Box and Williams 2000, p. 113-114; D.N. Shelton 
pers. comm. 1998); oval pigtoe (Butler unpub. data 1993, 1999, 2002; 
Brim Box and Williams 2000, p. 116-117; Williams unpub. data 2000); and 
Chipola slabshell (Butler unpub. data 1993, 2000; Brim Box and Williams 
2000, p. 95-96).

Unit 3: Uchee Creek, Alabama

    Unit 3 encompasses 34.2 km (21.2 mi) of the main stem of Uchee 
Creek from its confluence with the Chattahoochee River upstream to 
Island Creek in Russell County, Alabama. This unit is designated for 
the shinyrayed pocketbook (Brim Box and Williams 2000, p. 109-110; 
Gangloff unpublished data 2005).

Unit 4: Sawhatchee Creek and Kirkland Creek, Georgia

    Unit 4 includes the main stems of Sawhatchee Creek and Kirkland 
Creek and one tributary of Sawhatchee Creek, encompassing a total 
stream length of 37.8 km (23.5 mi) in Early County, GA. The main stem 
of Sawhatchee Creek as proposed extends from its confluence with the 
Chattahoochee River upstream 28.6 km (17.8 mi) to the powerline 
crossing located 1.4 km (0.87 mi) upstream of County Road 15, Early 
County, GA. The main stem of Kirkland Creek extends from its confluence 
with the Chattahoochee River upstream 6.1 km (3.8 mi) to Dry Creek, 
Early County, GA. The tributary, Sheffield Mill Creek, is included from 
its confluence with Sawhatchee Creek upstream 3.1 km (1.9 mi) to the 
powerline crossing located 2.3 km (1.4 mi) upstream of Sowhatchee Road, 
Early County, GA. Unit 4 is designated for the shinyrayed pocketbook, 
Gulf moccasinshell, and oval pigtoe (Brim Box and Williams 2000, p. 
109-110, 113-114, 116-117; Abbott pers. comm. 2005; Stringfellow pers. 
comm. 2003).

Unit 5: Upper Flint River, Georgia

    Unit 5 includes the main stem of the Flint River and eight of its 
tributaries upstream of Lake Blackshear, plus two tributaries that flow 
into Lake Blackshear, encompassing a total stream length of 380.4 km 
(236.4 mi) in Coweta, Crawford, Crisp, Dooly, Fayette, Macon, 
Meriwether, Peach, Pike, Spalding, Sumter, Talbot , Taylor, Upson, and 
Worth counties, Georgia. The main stem of the Flint River in proposed 
Unit 5 extends from the State Highway 27 bridge (Vienna Road) in Dooly 
and Sumter counties, Georgia (the river is the county boundary), 
upstream 247.4 km (153.7 mi) to Horton Creek in Fayette and Spalding 
counties, Georgia (the river is the county boundary). The downstream 
extent of each tributary within the unit is its mouth (its confluence 
with the water body named), and the upstream extent is the landmark 
listed. The nine tributary streams in Unit 5 are: Swift Creek, from 
Lake Blackshear upstream 11.3 km (7 mi) to Rattlesnake Branch in Crisp 
and Worth counties, Georgia (the creek is the county boundary); 
Limestone Creek, from Lake Blackshear in Crisp County, Georgia, 
upstream 8.8 km (5.5 mi) to County Road 89 in Dooly County, Georgia; 
Turkey Creek, from the Flint River upstream 21.7 km (13.5 mi) to Rogers 
Branch in Dooly County, Georgia; Pennahatchee Creek, from Turkey Creek 
upstream 4.8 km (3 mi) to Little Pennahatchee Creek in Dooly County, 
Georgia; Little Pennahatchee Creek, from Pennahatchee Creek upstream 
5.8 km (3.6 mi) to Rock Hill Creek in Dooly County, Georgia; Hogcrawl 
Creek, from the Flint River upstream 21.6 km (13.4 mi) to Little Creek 
in Dooly and Macon counties, Georgia (the creek is the county 
boundary); Red Oak Creek, from the Flint River upstream 21.7 km (13.5 
mi) to Brittens Creek in Meriwether County, Georgia; Line Creek, from 
the Flint River upstream 15.8 km (9.8 mi) to Whitewater Creek in Coweta 
and Fayette counties, Georgia (the creek is the county boundary); and 
Whitewater Creek, from Line Creek upstream 21.5 km (13.4 mi) to Ginger 
Cake Creek in Fayette County, Georgia.
    Unit 5 is designated for the shinyrayed pocketbook (Dinkins pers. 
comm. 1999, 2003; P.D. Johnson pers. comm. 2003; Brim Box and Williams 
2000, p. 109-110; Roe 2000; L. Andrews pers. comm. 2000; Blalock-Herod 
unpub. data 1997; Butler and Brim Box 1995, p. 3); Gulf moccasinshell 
(Edwards Pittman Environmental 2004; McCafferty pers. comm. 2003; 
Dinkins pers. comm. 2002; Brim Box and Williams 2000, p. 113-114; 
Andrews pers. comm. 2000; Blalock-Herod unpub. data 1997; Butler and 
Brim Box 1995, p. 3); oval pigtoe (Edwards Pittman Environmental 2004; 
McCafferty pers. comm. 2003; Dinkins pers. comm. 2002, 2003; 
Stringfellow pers. comm. 2000, 2003; Abbott pers. comm. 2001; Brim Box 
and Williams 2000, p. 116-117; Andrews pers. comm. 2000; Blalock-Herod 
unpub. data 1997); and purple bankclimber (Winterringer CCR pers. comm. 
2003; Dinkins pers. comm. 2003; P.D. Johnson pers. comm. 2003; Albanese 
pers. comm. 2003 regarding unpub. data from De Genachete and CCR; Brim 
Box and Williams 2000, p. 105-106; E. Van De Genachete pers. comm. 
1999).
    Unit 5 is divided into two maps in the Proposed Regulation 
Promulgation section of this proposed rule, one for the southern part 
and one for the northern part of the unit. The ``match line'' for 
joining these two maps is where the county boundary between Crawford 
and Upson counties, Georgia, meets the Flint River.

Unit 6: Middle Flint River, Georgia

    Unit 6 includes the main stem of the Flint River between Lake Worth 
(impounded by the Flint River Dam near Albany) and the Warwick Dam 
(which impounds Lake Blackshear), and nine tributaries, encompassing a 
total stream length of 302.3 km (187.8 mi) in Dougherty, Lee, Marion, 
Schley, Sumter, Terrell, Webster, and Worth counties, Georgia. The main 
stem of the Flint River in Unit 6 extends from Piney Woods Creek in 
Dougherty County, Georgia (the approximate upstream extent of Lake 
Worth), upstream 39.9 km (24.8 mi) to the Warwick Dam in Lee and Worth 
counties, Georgia. The downstream extent of each tributary within the 
unit is its mouth (its confluence with the water body named), and the 
upstream extent is the landmark listed. The nine tributaries of the 
Middle Flint River in Unit 6 are: Kinchafoonee Creek, from the Lee-
Dougherty county line (the approximate upstream extent of Lake Worth) 
upstream 107.6 km (66.8 mi) to Dry Creek in Webster County, Georgia; 
Lanahassee Creek, from Kinchafoonee

[[Page 32762]]

Creek upstream 9.3 km (5.8 mi) to West Fork Lanahassee Creek in Webster 
County, Georgia; Muckalee Creek, from the Lee'Dougherty county line 
(the approximate upstream extent of Lake Worth) upstream 104.5 km (64.9 
mi) to County Road 114 in Marion County, Georgia; Little Muckalee 
Creek, from Muckalee Creek in Sumter County, Georgia, upstream 7.2 km 
(4.5 mi) to Galey Creek in Schley County, Georgia; Mill Creek, from the 
Flint River upstream 3.2 km (2 mi) to Mercer Millpond Creek in Worth 
County, Georgia; Mercer Millpond Creek, from Mill Creek upstream 0.45 
km (0.28 mi) to Mercer Millpond in Worth County, Georgia; Abrams Creek, 
from the Flint River upstream 15.9 km (9.9 mi) to County Road 123 in 
Worth County, Georgia; Jones Creek, from the Flint River upstream 3.8 
km (2.4 mi) to County Road 123 in Worth County, Georgia; and Chokee 
Creek, from the Flint River upstream 10.5 km (6.5 mi) to Dry Branch 
Creek in Lee County, Georgia.
    Unit 6 is designated for the shinyrayed pocketbook (Crow CCR pers. 
comm. 2004; Edwards Pittman Environmental 2004; Albanese pers. comm. 
2003 regarding unpub. data from CCR; DeGarmo unpub. data 2002; 
McCafferty pers. comm. 2000, 2001; Golladay unpub. data 2001, 2002; P. 
Johnson unpub. data 1999; Blalock-Herod unpub. data 1997; Dinkins pers. 
comm. 1995; Brim Box and Williams 2000, p. 109-110), Gulf moccasinshell 
(Wisnewski unpub. data 2005; DeGarmo unpub. data 2002; Albanese pers. 
comm. 2003 regarding unpub. data from D. Shelton; P. Johnson unpub. 
data 1999; Brim Box and Williams 2000, p. 113-114; Weston 1995), oval 
pigtoe (Wisnewski unpub. data 2005; Crow CCR pers. comm. 2004; Albanese 
pers. comm. 2003 regarding unpub. data from CCR; DeGarmo unpub. data 
2002; Stringfellow unpub. data 2002; Golladay unpub. data 2001, 2002; 
Brim Box and Williams 2000, p. 116-117; P. Johnson unpub. data 1999; 
Blalock-Herod unpub. data 1997; Weston 1995), and purple bankclimber 
(Tarbell 2004; Brim Box and Williams 2000, p. 105-106).
    Unit 6 is divided into two maps in the Proposed Regulation 
Promulgation section of this proposed rule, one for the western part 
and one for the eastern part of the unit. The ``match line'' for 
joining these two maps is Lake Worth in Dougherty County, Georgia.

Unit 7: Lower Flint River, Georgia

    Unit 7 includes the main stem of the Flint River between Lake 
Seminole (impounded by the Jim Woodruff Lock and Dam) and the Flint 
River Dam (which impounds Lake Worth), and nine tributaries, 
encompassing a total stream length of 396.7 km (246.5 mi) in Baker, 
Calhoun, Decatur, Dougherty, Early, Miller, Mitchell, and Terrell 
counties, GA. The main stem of the Flint River in Unit 7 extends from 
its confluence with Big Slough in Decatur County, GA (the approximate 
upstream extent of Lake Seminole) upstream 116.4 km (72.3 mi) to the 
Flint River Dam in Dougherty County, GA. The downstream extent of each 
tributary within the unit is its mouth (its confluence with the water 
body named), and the upstream extent is the landmark listed. The nine 
tributaries of the Lower Flint River in Unit 7 are: Spring Creek, from 
Smith Landing in Decatur County, Georgia (the approximate upstream 
extent of Lake Seminole), upstream 74.2 km (46.1 mi) to County Road 35 
in Early County, Georgia; Aycocks Creek, from Spring Creek upstream 
15.9 km (9.9 mi) to Cypress Creek in Miller County, Georgia; Dry Creek, 
from Spring Creek upstream 9.9 km (6.1 mi) to Wamble Creek in Early 
County, Georgia; Ichawaynochaway Creek, from the Flint River in Baker 
County, Georgia, upstream 68.6 km (42.6 mi) to Merrett Creek in Calhoun 
County, Georgia; Mill Creek, from Ichawaynochaway Creek upstream 7.4 km 
(4.6 mi) to County Road 163 in Baker County, Georgia; Pachitla Creek, 
from Ichawaynochaway Creek upstream 18.9 km (11.8 mi) to Little 
Pachitla Creek in Calhoun County, Georgia; Little Pachitla Creek, from 
Pachitla Creek upstream 5.8 km (3.6 mi) to Bear Branch in Calhoun 
County, Georgia; Chickasawhatchee Creek, from Ichawaynochaway Creek in 
Baker County, GA, upstream 64.5 km (40.1 mi) to U.S. Highway 82 in 
Terrell County, Georgia; and Cooleewahee Creek, from the Flint River 
upstream 15.1 km (9.4 mi) to Piney Woods Branch in Baker County, 
Georgia.
    Unit 7 is designated for the shinyrayed pocketbook (Gangloff 2005; 
McCafferty pers. comm. 2004; Stringfellow unpub. data 2003; Dinkins 
pers. comm. 2001, 2003; Golladay unpub. data 2001, 2002; P. Johnson 
unpub. data 1999; Albanese pers. comm. 2003 regarding unpub. data from 
CCR; Andrews pers. comm. 2000; Blalock-Herod unpub. data 1997; Brim Box 
and Williams 2000, p. 109-110; Butler unpub. data 1993), Gulf 
moccasinshell (Abbott pers. comm. 2005; Golladay unpub. data 2001, 
2002; P. Johnson unpub. data 1999; Brim Box and Williams 2000, p. 113-
114; Butler unpub. data 1998; Blalock-Herod unpub. data 1997), oval 
pigtoe (Dinkins pers. comm. 2001; Golladay unpub. data 2001, 2002; 
Andrews pers. comm. 2000; Brim Box and Williams 2000, p. 116-117; P. 
Johnson unpub. data 1999; Butler unpub. data 1998; Blalock-Herod unpub. 
data 1997), and purple bankclimber (S. Carlson unpub. data 2002; Brim 
Box and Williams 2000, p. 105-106).
    Unit 7 is divided into two maps in the Proposed Regulation 
Promulgation section of this proposed rule, one for the western part 
and one for the eastern part of the unit. The western part (Map 10) 
depicts the Spring Creek system and the eastern part (Map 11) depicts 
the lower Flint River system.

Unit 8: Apalachicola River, Florida

    Unit 8 includes the main stem of the Apalachicola River and two 
distributaries (channels flowing out of the main stem), encompassing a 
total stream length of 155.4 km (96.6 mi) in Calhoun, Franklin, 
Gadsden, Gulf, Jackson, and Liberty counties, Florida. The main channel 
of the Apalachicola River in Unit 8 extends from the downstream end of 
Bloody Bluff Island (river mile 15.3 on U.S. Army Corps of Engineers 
Navigation Charts) in Franklin County, Florida, upstream to the Jim 
Woodruff Lock and Dam in Gadsden and Jackson counties, Florida (the 
river is the county boundary). The upstream extent of each distributary 
within the unit is its point of departure from the main channel of the 
Apalachicola River, and the downstream extent is the landmark listed. 
The two distributaries of the Apalachicola River in Unit 6 are: Chipola 
Cutoff, from the Apalachicola River in Gulf County, Florida, downstream 
4.5 km (2.8 mi) to its confluence with the Chipola River in Gulf 
County, Florida; and Swift Slough, from the Apalachicola River in 
Liberty County, Florida, downstream 3.6 km (2.2 mi) to its confluence 
with the River Styx in Liberty County, Florida.
    Unit 8 is designated for the fat threeridge (Brim Box and Williams 
2000, p. 92-93; Williams unpub. data 2000; Miller 1998, p. 54, 2000; 
Richardson and Yokley 1996, p. 137; Flakes 2001) and purple bankclimber 
(Brim Box and Williams 2000, p. 105-106; Miller 1998, p. 55, 2000; 
Richardson and Yokley 1996, p. 137; Butler unpub. data 1993; Flakes 
2001).

Unit 9: Upper Ochlockonee River, Florida, Georgia

    Unit 9 includes the main stem of the Ochlockonee River upstream of 
Lake Talquin (impounded by the Jackson Bluff Dam) and three 
tributaries, encompassing a total stream length of 177.3 km (110.2 mi) 
in Gadsden and

[[Page 32763]]

Leon counties, Florida, and Grady and Thomas counties, Georgia. The 
main stem of the Ochlockonee River in Unit 9 extends from its 
confluence with Gulley Branch (the approximate upstream extent of Lake 
Talquin) in Gadsden and Leon counties, Florida (the river is the county 
boundary), upstream to Bee Line Road/County Road 306 in Thomas County, 
Georgia. The downstream extent of each tributary within the unit is its 
mouth (its confluence with the water body named), and the upstream 
extent is the landmark listed. The three tributary streams in Unit 9 
are: Barnetts Creek, from the Ochlockonee River upstream 20 km (12.4 
mi) to Grady County Road 170/Thomas County Road 74 in Grady and Thomas 
counties, Georgia (the creek is the county boundary); West Barnetts 
Creek, from Barnetts Creek upstream 10 km (6.2 mi) to GA Highway 111 in 
Grady County, Georgia; and Little Ochlockonee River, from the 
Ochlockonee River upstream 13.3 km (8.3 mi) to Roup Road/County Road 33 
in Thomas County, Georgia.
    Unit 9 is designated for the shinyrayed pocketbook (Blalock-Herod 
2003, p. 1; McCafferty pers. comm. 2003; Williams unpub. data 1993), 
Ochlockonee moccasinshell (Brim Box and Williams 2000, p. 60; Williams 
and Butler 1994, p. 64), oval pigtoe (Edwards Pittman Environmental 
2004; Blalock-Herod unpub. data 2003; Blalock-Herod 2003, p. 1; 
Williams unpub. data 1993), and purple bankclimber (Blalock-Herod 
unpub. data 2003; Blalock-Herod 2002, p. 1; Smith FDOT unpub. data 
2001; Williams unpub. data 1993).

Unit 10: Lower Ochlockonee River, Florida

    Unit 10 encompasses 75.4 km (46.9 mi) of the main stem of the 
Ochlockonee River from its confluence with Syfrett Creek in Wakulla 
County, Florida, upstream to the Jackson Bluff Dam (which impounds Lake 
Talquin) in Leon and Liberty counties, Florida. Unit 10 is designated 
for the purple bankclimber (Blalock-Herod unpub. data 2003; Williams 
unpub. data 1993).

Unit 11: Santa Fe River and New River, Florida

    Unit 11 includes the main stem of the Santa Fe River and its 
tributary the New River, encompassing a total stream length of 83.1 km 
(51.6 mi) in Alachua, Bradford, Columbia, and Union counties, Florida. 
The main stem of the Santa Fe River as proposed extends from where the 
river goes underground in O'Leno State Park in Alachua and Columbia 
counties, Florida (the river is the county boundary) upstream 60.2 km 
(37.4 mi) to the powerline crossing located 1.9 km (1.2 mi) downstream 
of U.S. Highway 301 in Alachua and Bradford counties, Florida (the 
river is the county boundary). The New River in proposed Unit 11 
extends from its confluence with the Santa Fe River at the junction of 
Alachua, Bradford, and Union counties, Florida, upstream 22.9 km (14.2 
mi) to McKinney Branch in Bradford and Union counties, Florida (the 
river is the county boundary). Unit 11 is designated for the oval 
pigtoe (Blalock-Herod and Williams 2001, p. 5; Blalock-Herod 2000, p. 
1-72; Williams unpub. data 1993, 1996-98).

Existing Critical Habitat

    Of the proposed critical habitat for the seven mussels, 147.3 km 
(91.5 mi) are already designated critical habitat for the Gulf sturgeon 
(Acipenser oxyrinchus desotoi) (68 FR 13370; March 19, 2003), which was 
listed as a threatened species under the Act on September 30, 1991 (56 
FR 49653). The area in common between the proposed mussels' habitat and 
the designated sturgeon habitat is entirely within Unit 8, the 
Apalachicola River.

Land Ownership

    States were granted ownership of lands beneath navigable waters up 
to the ordinary high water mark 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 
of Alabama, Florida, and Georgia. The lands beneath most nonnavigable 
waters and most riparian lands along the navigable and nonnavigable 
waters included in this proposed rule are in private ownership. Table 2 
lists the parcels of publicly owned lands within or adjacent to each 
proposed critical habitat unit. Units not listed do not contain 
publicly owned lands.

 Table 2.--Public Lands Within or Adjacent to Proposed Critical Habitat
                                  Units
------------------------------------------------------------------------
       Critical habitat unit                    Public lands
------------------------------------------------------------------------
1. Econfina Creek.................  Econfina Creek WtrMA.
2. Chipola River..................  Upper Chipola River WtrMA, South
                                     Marianna Trail and Canoe Launch,
                                     Apalachicola River WtrMA,
                                     Apalachicola River WEA, Chipola
                                     River GW, Florida Caverns SP,
                                     Judges Cave WEA, Marianna GW.
5. Upper Flint....................  Joe Kurz WMA, Sprewell Bluff SP and
                                     WMA, Big Lazer WMA, Montezuma NA,
                                     Flint River WMA.
7. Lower Flint....................  Flint River GW, Radium Springs
                                     Tract, Chickasawhatchee Flint WMA,
                                     Elmodel WMA, Lake Seminole WMA.
8. Apalachicola River.............  Angus Gholson Jr. Nature Park of
                                     Chattahoochee, Apalachicola River
                                     WtrMA, Apalachicola River WEA, Fort
                                     Gadsden HS, Torreya SP,
                                     Apalachicola NF.
9. Upper Ochlockonee..............  Joe Budd WMA, Lake Talquin SF.
10. Lower Ochlockonee.............  Lake Talquin SP, Lake Talquin SF,
                                     Tate's Hell SF, Apalachicola NF.
11. Santa Fe River and New River..  Santa Fe River Ranch, O'Leno SP,
                                     River Rise Preserve SP, Graham CA,
                                     Palatka-Lake Butler ST.
------------------------------------------------------------------------
Abbreviations: CA = Conservation Area, GW = Greenway, HS = Historic
  Site, NA = Natural Area, NF = National Forest, SF = State Forest, SP =
  State Park, ST = State Trail, WEA = Wildlife and Environmental Area,
  WMA = Wildlife Management Area, WtrMA = Water Management Area.

Effects of Critical Habitat Designation

Section 7 Consultation

    Section 7 of the Act requires Federal agencies, including the 
Service, to ensure that actions they fund, authorize, or carry out are 
not likely to destroy or adversely modify critical habitat. In our 
regulations at 50 CFR 402.02, we define destruction or adverse 
modification as ``a direct or indirect alteration that appreciably 
diminishes the value of critical habitat for both the survival and 
recovery of a listed species. Such alterations include, but are not 
limited to, alterations adversely modifying any of those physical or 
biological features that were the basis for determining the habitat to 
be critical.'' However, recent decisions by the 5th and 9th Circuit 
Court of Appeals (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

[[Page 32764]]

Wildlife Service et al., 245 F.3d 434, 442F (5th Cir 2001). Also see 
discussion on Role of Critical Habitat above) have invalidated this 
definition. Pursuant to current national policy and the statutory 
provisions of the Act, destruction or adverse modification is 
determined on the basis of whether, with implementation of the proposed 
Federal action, the affected critical habitat would remain functional 
(or retain the current ability for the PCEs to be functionally 
established) to serve the intended conservation role for the species.
    Section 7(a) of the Act requires Federal agencies, including the 
Service, 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 proposed or 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 
us on any action that is likely to jeopardize the continued existence 
of a proposed species or result in destruction or adverse modification 
of proposed critical habitat. However, once a proposed species becomes 
listed, or proposed critical habitat is designated as final, the full 
prohibitions of section 7(a)(2) apply to any Federal action. The 
primary utility of the conference procedures is to maximize the 
opportunity for a Federal agency to adequately consider proposed 
species and critical habitat and avoid potential delays in implementing 
their proposed action as a result of the section 7(a)(2) compliance 
process, should those species be listed or the critical habitat 
designated.
    Under conference procedures, the Service may provide advisory 
conservation recommendations to assist the agency in eliminating 
conflicts that may be caused by the proposed action. The Service may 
conduct either informal or formal conferences. Informal conferences are 
typically used if the proposed action is not likely to have any adverse 
effects on the proposed species or proposed critical habitat. Formal 
conferences are typically used when the Federal agency or the Service 
believes the proposed action is likely to cause adverse effects on 
proposed species or critical habitat, inclusive of those that may cause 
jeopardy or adverse modification.
    The results of an informal conference are typically transmitted in 
a conference report; while the results of a formal conference are 
typically transmitted in a conference opinion. Conference opinions on 
proposed critical habitat are typically prepared according to 50 CFR 
402.14, as if the proposed critical habitat were designated. We may 
adopt the conference opinion as the biological opinion when the 
critical habitat is designated, if no substantial new information or 
changes in the action alter the content of the opinion (see 50 CFR 
402.10(d)). Any conservation recommendations in a conference report or 
opinion are strictly advisory.
    If a species is listed or critical habitat is designated, 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 such a species or to destroy or adversely modify 
its critical habitat. 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. As a result of this consultation, 
compliance with the requirements of section 7(a)(2) will be documented 
through the Service's 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 are likely to adversely affect listed species or critical 
habitat.
    When we issue a biological opinion concluding that a project is 
likely to result in jeopardy to a listed species or the destruction or 
adverse modification of critical habitat, we also provide reasonable 
and prudent alternatives to the project, if any are identifiable. 
``Reasonable and prudent alternatives'' are defined at 50 CFR 402.02 as 
alternative actions identified during consultation that can be 
implemented in a manner consistent with the intended purpose of the 
action, that are consistent with the scope of the Federal agency's 
legal authority and jurisdiction, that are economically and 
technologically feasible, and that the Director believes would avoid 
jeopardy to the listed species or destruction or adverse modification 
of 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 a new 
species is listed or critical habitat is subsequently designated that 
may be affected and the Federal agency has retained discretionary 
involvement or control over the action or such discretionary 
involvement or control is authorized by law. Consequently, some Federal 
agencies may request reinitiation of consultation with us on actions 
for which formal consultation has been completed, if those actions may 
affect subsequently listed species or designated critical habitat or 
adversely modify or destroy proposed critical habitat.
    Federal activities that may affect any of the seven species or 
their designated critical habitat will require section 7 consultation 
under the Act. Activities on State, Tribal, local, or private lands 
requiring a Federal permit (such as a permit from the USACE under 
section 404 of the Clean Water Act or a permit under section 
10(a)(1)(B) of the Act from the Service) or involving some other 
Federal action (such as funding from the Federal Highway 
Administration, Federal Aviation Administration, or the Federal 
Emergency Management Agency) will also be subject to the section 7 
consultation process. Federal actions not affecting listed species or 
critical habitat, and actions on State, Tribal, local, or private lands 
that are not federally funded, authorized, or permitted, do not require 
section 7 consultations.

Application of the Jeopardy and Adverse Modification Standards for 
Actions Involving Effects to the Seven Mussels and Their Critical 
Habitat

Jeopardy Standard

    Prior to and following designation of critical habitat, the Service 
has applied an analytical framework for jeopardy analyses of the seven 
mussels that relies heavily on the importance of core area populations 
to the mussels' survival and recovery. The section 7(a)(2) analysis is 
focused not only on these populations but also on the habitat 
conditions necessary to support them.
    The jeopardy analysis usually expresses the survival and recovery 
needs of the seven mussels in a qualitative fashion without making 
distinctions between what is necessary for survival and what is 
necessary for recovery. Generally, if a proposed Federal action is 
incompatible with the viability of the affected core area 
population(s), inclusive of associated habitat conditions, a jeopardy 
finding is considered to be warranted, because of the relationship of 
each core area population to the survival and recovery of the species 
as a whole.

Adverse Modification Standard

    The analytical framework described in the Director's December 9, 
2004, memorandum is used to complete

[[Page 32765]]

section 7(a)(2) analyses for Federal actions affecting the seven 
mussels' critical habitat. The key factor related to the adverse 
modification determination is whether, with implementation of the 
proposed Federal action, the affected critical habitat would remain 
functional (or retain the current ability for the PCEs to be 
functionally established) to serve the intended conservation role for 
the species. Generally, the conservation role of the seven mussels' 
critical habitat units is to support viable core area populations.
    Section 4(b)(8) of the Act requires us to briefly evaluate and 
describe in any proposed or final regulation that designates critical 
habitat those activities involving a Federal action that may destroy or 
adversely modify such habitat, or that may be affected by such 
designation. Activities that may destroy or adversely modify critical 
habitat may also jeopardize the continued existence of the species.
    Activities that may destroy or adversely modify critical habitat 
are those that alter the PCEs to an extent that the conservation value 
of critical habitat for the seven mussels is appreciably reduced. 
Activities that, when carried out, funded, or authorized by a Federal 
agency, may affect critical habitat and therefore result in 
consultation for the seven mussels include, but are not limited to:
    (1) Actions that would induce channel instability or significantly 
alter channel morphology. Such activities could include, but are not 
limited to, channelization, impoundment, road and bridge construction, 
mining, dredging, destruction of riparian vegetation, and changes in 
land cover, such as urbanization and clear-cut logging, that 
substantially alter the runoff characteristics of the watershed. These 
activities may alter sediment and water discharge in the channel, which 
results in smothering the stream bed with, or eroding it to, materials 
that are unsuitable substrates for the normal behavior, growth, and 
survival of the adult and juvenile life stages. These activities may 
initiate or accelerate bank erosion, which results in wider and 
shallower channels, more extreme temperatures, and chemical properties 
that are unsuitable for the normal behavior, growth, and survival of 
one or more life stages.
    (2) Actions that would significantly decrease the proportion of 
coarse sediments (sand, gravel, cobble) in the stream bed. Such 
activities could include, but are not limited to, sedimentation from 
livestock grazing, road and bridge construction, mining, dredging, 
timber harvest, off-road vehicle use, and other activities that 
increase erosion rates in the channel or the watershed and deposition 
of fine sediments. These activities could reduce or eliminate the 
coarse substrates that provide for the normal behavior, growth, and 
survival of all life stages, and could increase the exposure of the 
juvenile and adult life stages to harmful contaminants that adhere to 
fine sediments.
    (3) Actions that would significantly alter the flow regime. Such 
activities could include, but are not limited to, the construction and 
operation of dams, water withdrawals, water diversions, and changes in 
land cover that substantially alter the runoff characteristics of the 
watershed, such as urbanization and clear-cut logging. These activities 
could alter the spatial distribution, timing, and duration of depths 
and velocities in the channel that provide for the normal behavior, 
growth, and survival of one or more mussel life stages.
    (4) Actions that would significantly alter physical and chemical 
water conditions. Such activities could include, but are not limited 
to, the release of chemicals, nutrients, biological pollutants, or 
heated effluents into the surface water or connected groundwater at a 
point source or by dispersed release (non-point source). These 
activities could alter water conditions that provide for the normal 
behavior, growth, and survival of one or more mussel life stages. These 
activities could promote the excessive growth of filamentous algae and 
other organisms that preclude the normal behavior, growth, and survival 
of one or more mussel life stages.
    (5) Actions that would significantly reduce the density of host 
fishes. Such activities could include, but are not limited to, 
channelization, impoundment, mining, and dredging. These activities 
could alter the composition of the fish community such that the rate of 
host fish infection and completion of the larval life stage is too low 
to sustain a stable or increasing mussel population and normal rates of 
dispersal and genetic exchange with other areas.
    We consider all of the units proposed as critical habitat to 
contain features essential to the conservation of the seven mussels. 
All of the units are within the geographic range of the seven species, 
were occupied at the time of listing (based on surveys completed 1990 
to 1998), and are likely occupied currently (based on additional 
surveys between 1998 and the present, and on the longevity and relative 
immobility of mussels). Federal agencies already consult with us on 
actions in areas currently occupied by and that may affect the seven 
mussels to ensure that these actions do not jeopardize the mussels' 
continued existence.

Application of Section 3(5)(a) and Exclusions Under Section 4(b)(2) of 
the Act

    The 11 units we propose as critical habitat satisfy the definition 
of critical habitat under section 3(5)(A) of the Act in that each is a 
specific area within the geographical area occupied by one or more of 
the seven mussels at the time of listing within which are found those 
physical and biological features that are essential to their 
conservation and that may require special management considerations or 
protection (see ``Primary Constituent Elements'', ``Criteria Used to 
Delineate Critical Habitat'', and ``Special Management Considerations 
or Protection''). We considered whether conservation activity on 
publicly or privately managed lands within a proposed unit might remove 
the need for special management considerations or protection from all 
or part of a unit.
    Several stream reaches within the proposed critical habitat units 
run through or adjacent to public lands that are managed wholly or 
partially for conservation purposes (see ``Land Ownership''). None of 
the management plans for these areas provide assurance of effective 
conservation for the mussels or features essential to their 
conservation, because all of the areas are affected to some degree by 
threats upstream and outside of their boundaries that may degrade one 
or more of the PCEs within their boundaries. We describe PCE- and unit-
specific threats under ``Special Management Considerations or 
Protection.'' At this time, the Service has not received applications 
for or issued incidental take permits that would require an HCP for one 
or more of the seven mussels. Further, we do not foresee not including 
particular areas in this proposal that are occupied and contain the 
PCEs but do not require special management or protection.
    Under section 4(b)(2) of the Act, we must consider the economic 
impact, impact on national security, and any other relevant impact of 
designating areas as critical habitat. We may exclude any area from 
critical habitat if we determine that the benefits of exclusion 
outweigh the benefits of inclusion.

Benefits of Inclusion

    The most direct benefit of critical habitat is that actions taken, 
authorized, or funded by the Federal government

[[Page 32766]]

require consultation under section 7 of the Act to ensure that these 
actions are not likely to destroy or adversely modify critical habitat 
(see ``Effects of Critical Habitat Designation--Section 7 
Consultation''). This regulatory benefit has two principal limitations. 
First, it applies only to Federal actions and not to other actions that 
may destroy or adversely modify critical habitat. Second, it ensures 
only that designated areas are not destroyed or adversely modified and 
does not require specific steps toward recovery.
    Another benefit of critical habitat is that its designation serves 
to educate landowners, State and local governments, and the general 
public. By clearly delineating areas of high conservation value, 
designation may help focus and promote conservation efforts for the 
seven mussels. Designation informs State agencies and local governments 
about areas that they may consider for protection or conservation under 
State laws or local ordinances.

Benefits of Exclusion

    Because the regulatory effect of critical habitat is limited to 
Federal actions, the non-economic impacts of critical habitat are 
generally limited to Federal lands, partnerships, and trust resources. 
We have determined that the streams within the proposed critical 
habitat units for the seven mussels are not owned or managed by the 
Department of Defense, there are currently no HCPs for the seven 
mussels, and the proposed designation does not include any Tribal 
lands. We anticipate no impact to national security, Tribal lands, 
partnerships, or habitat conservation plans from this critical habitat 
designation as proposed.
    Based on the best available information, we believe that the 
benefits of designating each of the 11 units we propose as critical 
habitat outweigh the non-economic benefits of excluding any specific 
areas within those units. We will evaluate potential economic benefits 
of exclusion in a separate notice (see ``Economic Analysis'').

Economic Analysis

    An analysis of the economic impacts of proposing critical habitat 
for the seven mussels is being prepared. We will announce the 
availability of the draft economic analysis as soon as it is completed, 
at which time we will seek public review and comment. At that time, 
copies of the draft economic analysis will be available for downloading 
from the Internet at http://www.fws.gov/panamacity/ or by contacting 
the Panama City, Florida, Fish and Wildlife Office directly (see 
ADDRESSES section). For further explanation, see the ``Regulatory 
Flexibility Act'' and ``Regulatory Planning and Review'' discussions 
below.

Peer Review

    In accordance with our joint policy 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 such review is to ensure 
that our critical habitat designation is based on scientifically sound 
data, assumptions, and analyses. We will send copies of this proposed 
rule to these peer reviewers immediately following publication in the 
Federal Register. We will invite these peer reviewers to comment, 
during the public comment period, on the specific assumptions and 
conclusions regarding the proposed designation of critical habitat.
    We will consider all comments and information received during the 
comment period on this proposed rule during preparation of a final 
rulemaking. Accordingly, the final decision may differ from this 
proposal.

Public Hearings

    The Act provides for one or more public hearings on this proposal, 
if requested. Requests for public hearings must be made in writing at 
least 15 days prior to the close of the public comment period. We 
intend to schedule public hearings once the draft economic analysis is 
available so that we can take public comment on the proposed 
designation and the economic analysis simultaneously. However, we can 
schedule public hearings on this proposal prior to that time, if any 
are requested, and announce the dates, times, and places of those 
hearings in the Federal Register and local newspapers at least 15 days 
prior to the first hearing.

Clarity of the Rule

    Executive Order 12866 requires each agency to write regulations and 
notices that are easy to understand. We invite your comments on how to 
make this proposed rule easier to understand, including answers to 
questions such as the following: (1) Are the requirements in the 
proposed rule clearly stated? (2) Does the proposed rule contain 
technical jargon that interferes with the clarity? (3) Does the format 
of the proposed rule (grouping and order of the sections, use of 
headings, paragraphing, and so forth) aid or reduce its clarity? (4) Is 
the description of the notice in the SUPPLEMENTARY INFORMATION section 
of the preamble helpful in understanding the proposed rule? (5) What 
else could we do to make this proposed rule easier to understand?
    Send a copy of any comments on how we could make this proposed rule 
easier to understand to: Office of Regulatory Affairs, Department of 
the Interior, Room 7229, 1849 C Street, NW., Washington, DC 20240. You 
may e-mail your comments to this address: [email protected].

Required Determinations

Regulatory Planning and Review

    In accordance with Executive Order 12866, this document is a 
significant rule in that it may raise novel legal and policy issues, 
but it is not anticipated to have an annual effect on the economy of 
$100 million or more or affect the economy in a material way. Due to 
the tight timeline for publication in the Federal Register, the Office 
of Management and Budget (OMB) has not formally reviewed this rule. We 
are preparing a draft economic analysis of this proposed action, which 
will be available for public comment, to determine the economic 
consequences of designating the specific areas as critical habitat. 
This economic analysis also will be used to determine compliance with 
Executive Order 12866, Regulatory Flexibility Act, Small Business 
Regulatory Enforcement Fairness Act, and Executive Order 12630.
    Within these areas, the types of Federal actions or authorized 
activities that we have identified as potential concerns are listed 
above in the section on Section 7 Consultation. The availability of the 
draft economic analysis will be announced in the Federal Register and 
in local newspapers so that it is available for public review and 
comments. The draft economic analysis can be obtained from the Internet 
Web site at http://www.fws.gov/panamacity/ or by contacting the Panama 
City, Florida, Fish and Wildlife Service office directly (see ADDRESSES 
section).

Regulatory Flexibility Act (5 U.S.C. 601 et seq.)

    Our assessment of economic effect will be completed prior to final 
rulemaking based upon review of the draft economic analysis prepared 
pursuant to section 4(b)(2) of the Act and E.O. 12866. This analysis is 
for the purposes of compliance with the Regulatory Flexibility Act and 
does not reflect our position on the type of

[[Page 32767]]

economic analysis required by New Mexico Cattle Growers Assn. v. U.S. 
Fish and Wildlife Service 248 F.3d 1277 (10th Cir. 2001).
    Under the Regulatory Flexibility Act (5 U.S.C. 601 et seq., as 
amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA) of 1996), 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 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 Regulatory 
Flexibility Act (RFA) to require Federal agencies to provide a 
statement of the factual basis for certifying that the rule will not 
have a significant economic impact on a substantial number of small 
entities.
    At this time, the Service lacks the available economic information 
necessary to provide an adequate factual basis for the required RFA 
finding. Therefore, the RFA finding is deferred until completion of the 
draft economic analysis prepared pursuant to section 4(b)(2) of the Act 
and E.O. 12866. This draft economic analysis will provide the required 
factual basis for the RFA finding. Upon completion of the draft 
economic analysis, the Service will publish a notice of availability of 
the draft economic analysis of the proposed designation and reopen the 
public comment period for the proposed designation. The Service will 
include with the notice of availability, as appropriate, an initial 
regulatory flexibility analysis or a certification that the rule will 
not have a significant economic impact on a substantial number of small 
entities accompanied by the factual basis for that determination. The 
Service has concluded that deferring the RFA finding until completion 
of the draft economic analysis is necessary to meet the purposes and 
requirements of the RFA. Deferring the RFA finding in this manner will 
ensure that the Service makes a sufficiently informed determination 
based on adequate economic information and provides the necessary 
opportunity for public comment.

Executive Order 13211

    On May 18, 2001, the President issued an Executive Order (E.O. 
13211) on regulations that significantly affect energy supply, 
distribution, and use. Executive Order 13211 requires agencies to 
prepare Statements of Energy Effects when undertaking certain actions. 
This proposed rule to designate critical habitat for the seven mussels 
is a significant rule under Executive Order 12866 in that it may raise 
novel legal and policy issues, but it is not expected to significantly 
affect energy supplies, distribution, or use. Therefore, this action is 
not a significant energy action, and no Statement of Energy Effects is 
required.

Unfunded Mandates Reform Act (2 U.S.C. 1501 et seq.)

    In accordance with the Unfunded Mandates Reform Act (2 U.S.C. 
1501), the Service makes the following findings:
    (a) This rule will 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 tribal 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 tribal 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 Government 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. 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 on to State governments.
    (b) We do not believe that this rule will significantly or uniquely 
affect small governments because the proposed units are streams, 
unauthorized take of the seven mussels within and outside the units is 
already prohibited, and critical habitat provides no incremental 
restrictions. 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.

Federalism

    In accordance with Executive Order 13132, the rule does not have 
significant Federalism effects. A Federalism assessment is not 
required. In keeping with DOI 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, Florida, and Georgia. The designation of critical 
habitat in areas currently occupied by the seven mussels, we believe, 
imposes little to no additional restrictions to those currently in 
place and, therefore, has little incremental impact on State and local 
governments and their activities. The designation may have some benefit 
to these governments in that the areas that contain the features 
essential to the conservation of the species are more clearly defined, 
and the primary constituent elements of the habitat necessary to the 
conservation of the species are specifically identified. While making 
this definition and identification does not alter where and what 
federally sponsored activities may occur, it may assist these local

[[Page 32768]]

governments in long-range planning (rather than waiting for case-by-
case section 7 consultations to occur).

Civil Justice Reform

    In accordance with Executive Order 12988, the Office of the 
Solicitor has determined that the rule does not unduly burden the 
judicial system and 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 primary constituent 
elements within the designated areas to assist the public in 
understanding the habitat needs of the seven mussels.

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. 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

    It is our position that, outside the Tenth Circuit, we do not need 
to prepare environmental analyses as defined by the NEPA in connection 
with designating critical habitat under the Endangered Species Act of 
1973, as amended. We published a notice outlining our reasons for this 
determination in the Federal Register on October 25, 1983 (48 FR 
49244). This assertion was upheld in the courts of the Ninth Circuit 
(Douglas County v. Babbitt, 48 F.3d 1495 (9th Cir. Ore. 1995), cert. 
denied 116 S. Ct. 698 (1996)).

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), Executive Order 13175, and the Department 
of 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. We have determined that 
there are no tribal lands with features essential to the conservation 
of the seven mussels. Therefore, critical habitat for the seven mussels 
has not been designated on tribal lands.

References Cited

    A complete list of all references cited in this rulemaking is 
available upon request from the Field Supervisor, Panama City Fish and 
Wildlife Office (see ADDRESSES section).

Author

    The primary author of this package is the Panama City Fish and 
Wildlife Office (see ADDRESSES section).

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--[AMENDED]

    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. In Sec.  17.11(h), revise the entries for ``Bankclimber, purple 
(mussel),'' ``Moccasinshell, Gulf,'' ``Moccasinshell, Ochlockonee,'' 
``Pigtoe, oval,'' ``Pocketbook, shinyrayed,'' ``Slabshell, Chipola,'' 
and ``Threeridge, fat (mussel),'' listed in alphabetical order under 
``CLAMS'' to read as follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

--------------------------------------------------------------------------------------------------------------------------------------------------------
                        Species                                                    Vertebrate
--------------------------------------------------------                        population where                                  Critical     Special
                                                            Historic range       endangered or         Status      When listed    habitat       rules
           Common name                Scientific name                              threatened
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
              Clams
 
                                                                      * * * * * * *
Bankclimber, purple (mussel).....  Elliptoideus          U.S.A. (AL, FL, GA)  NA.................  T                       633     17.95(f)           NA
                                    sloatianus.
 
                                                                      * * * * * * *
Moccasinshell, Gulf..............  Medionidus            U.S.A. (AL, FL, GA)  NA.................  E                       633     17.95(f)           NA
                                    penicillatus.
 
                                                                      * * * * * * *
Moccasinshell, Ochlockonee.......  Medionidus            U.S.A. (FL, GA)....  NA.................  E                       633     17.95(f)           NA
                                    simpsonianus.
 
                                                                      * * * * * * *
Pigtoe, oval.....................  Pleurobema pyriforme  U.S.A. (AL, FL, GA)  NA.................  E                       633     17.95(f)           NA
 
                                                                      * * * * * * *
Pocketbook, shinyrayed...........  Lampsilis             U.S.A. (AL, FL, GA)  NA.................  E                       633     17.95(f)           NA
                                    subangulata.
 
                                                                      * * * * * * *
Slabshell, Chipola...............  Elliptio              U.S.A. (AL, FL)....  NA.................  T                       633     17.95(f)           NA
                                    chipolaensis.
 

[[Page 32769]]

 
                                                                      * * * * * * *
Threeridge, fat (mussel).........  Amblema neislerii...  U.S.A. (FL, GA)....  NA.................  E                       633     17.95(f)           NA
 
                                                                      * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------

    3. In Sec.  17.95, at the end of paragraph (f), add an entry for 
seven mussel species (in four northeast Gulf of Mexico drainages) to 
read as follows:


Sec.  17.95  Critical habitat--fish and wildlife.

* * * * *
    (f) Clams and snails.
* * * * *
    Seven mussel species (in four northeast Gulf of Mexico drainages): 
purple bankclimber (Elliptoideus sloatianus), Gulf moccasinshell 
(Medionidus penicillatus), Ochlockonee moccasinshell (Medionidus 
simpsonianus), oval pigtoe (Pleurobema pyriforme), shinyrayed 
pocketbook (Lampsilis subangulata), Chipola slabshell (Elliptio 
chipolaensis), and fat threeridge (Amblema neislerii).
    (1) Critical habitat units are depicted on the maps below for the 
following counties:
    (i) Alabama: Houston and Russell;
    (ii) Florida: Alachua, Bay, Bradford, Calhoun, Columbia, Franklin, 
Gadsden, Gulf, Jackson, Leon, Liberty, Union, Wakulla, and Washington; 
and
    (iii) Georgia: Baker, Calhoun, Clayton, Coweta, Crawford, Crisp, 
Decatur, Dooly, Dougherty, Early, Fayette, Grady, Lee, Macon, Marion, 
Meriwether, Miller, Mitchell, Peach, Pike, Schley, Spalding, Sumter, 
Talbot, Taylor, Terrell, Thomas, Upson, Webster, and Worth.
    (2) The primary constituent elements of critical habitat for the 
purple bankclimber (Elliptoideus sloatianus), Gulf moccasinshell 
(Medionidus penicillatus), Ochlockonee moccasinshell (Medionidus 
simpsonianus), oval pigtoe (Pleurobema pyriforme), shinyrayed 
pocketbook (Lampsilis subangulata), Chipola slabshell (Elliptio 
chipolaensis), and fat threeridge (Amblema neislerii) are:
    (i) A geomorphically stable stream channel (a channel that 
maintains its lateral dimensions, longitudinal profile, and spatial 
pattern over time without an aggrading or degrading bed elevation);
    (ii) A predominantly sand, gravel, and/or cobble stream substrate;
    (iii) Permanently flowing water;
    (iv) Water quality (including temperature, turbidity, dissolved 
oxygen, and chemical constituents) that meets or exceeds the current 
aquatic life criteria established under the Clean Water Act (33 U.S.C. 
1251-1387); and
    (v) Fish hosts (such as largemouth bass, sailfin shiner, brown 
darter) that support the larval life stages of the seven mussels.
    (3) Critical habitat does not include manmade structures (such as 
buildings, aqueducts, airports, roads, and other paved areas, and the 
land on which such structures are located) existing on the effective 
date of this rule and not containing one or more of the primary 
constituent elements.
    (4) Critical habitat unit maps. 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. The following data sources were referenced to 
identify upstream and downstream extents of critical habitat units: 
USGS 7.5' quadrangles; Georgia Department of Transportation county 
highway maps; U.S. Census Bureau 1:100,000 TIGER line road data; 1993 
Georgia digital orthographic quarter quads (DOQQs); 2004 Florida DOQQs; 
and DeLorme Atlas and Gazetteers for Alabama, Florida, and Georgia. The 
projection used in mapping all units was Universal Transverse Mercator 
(UTM), NAD 83, Zone 16 North.
    (5) Note: Index map (Map 1) showing critical habitat units in the 
States of Alabama, Florida, and Georgia for the seven mussels follows:
BILLING CODE 4310-55-P

[[Page 32770]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.005

    (6) Table of listed species and critical habitat units. A table 
showing the listed species, their respective critical habitat units, 
and the States that contain those habitat units follows. Detailed 
critical habitat unit descriptions and maps

[[Page 32771]]

appear below in paragraphs (7) through (17).

 Table of Seven Mussel Species, Their Critical Habitat Units, and States
                 Containing Those Critical Habitat Units
------------------------------------------------------------------------
                                    Critical habitat
            Species                      units               States
------------------------------------------------------------------------
Purple bankclimber               Units 5, 6, 7, 8, 9,   AL, FL, GA.
 (Elliptoideus sloatianus).       10.
Gulf moccasinshell (Medionidus   Units 1, 2, 4, 5, 6,   AL, FL, GA.
 penicillatus).                   7.
Ochlockonee moccasinshell        Unit 9...............  FL, GA.
 (Medionidus simpsonianus).
Oval pigtoe (Pleurobema          Units 1, 2, 4, 5, 6,   AL, FL, GA.
 pyriforme).                      7, 9, 11.
Shinyrayed pocketbook            Units 2, 3, 4, 5, 6,   AL, FL, GA.
 (Lampsilis subangulata).         7, 9.
Chipola slabshell (Elliptio      Unit 2...............  AL, FL.
 chipolaensis).
Fat threeridge (mussel)          Units 2, 8...........  AL, FL, GA.
 (Amblema neislerii).
------------------------------------------------------------------------

    (7) Unit 1. Econfina and Moccasin creeks, Bay and Washington 
Counties, Florida. This is a critical habitat unit for the Gulf 
moccasinshell and oval pigtoe.
    (i) General Description: Unit 1 includes the main stem of Econfina 
Creek and one of its tributaries, Moccasin Creek, encompassing a total 
stream length of 31.4 kilometers (km) (19.5 miles (mi)). The main stem 
of Econfina Creek extends from its confluence with Deer Point Lake at 
the powerline crossing located 3.8 km (2.3 mi) downstream of Bay County 
Highway 388 (-85.56 longitude 30.36 latitude), Bay County, Florida, 
upstream 28.6 km (17.8 mi) to Tenmile Creek (-85.50 longitude, 30.51 
latitude), Washington County, Florida; and Moccasin Creek from its 
confluence with Econfina Creek upstream 2.8 km (1.7 mi) to Ellis Branch 
(-85.53 longitude, 30.41 latitude), Bay County, Florida.
    (ii) Note: Unit 1 map (Map 2) follows:

[[Page 32772]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.006


[[Page 32773]]


    (8) Unit 2. Chipola River and Dry, Rocky, Waddells Mill, Baker, 
Marshall, and Big Creeks; Houston County, Alabama; and Calhoun, Gulf, 
and Jackson counties, Florida. This is a critical habitat unit for the 
fat threeridge, shinyrayed pocketbook, Gulf moccasinshell, oval pigtoe, 
and Chipola slabshell.
    (i) General Description: Unit 2 includes the main stem of the 
Chipola River and six of its tributaries, encompassing a total stream 
length of 190.0 km (118.1 mi). The main stem of the Chipola River 
extends from its confluence with the Apalachicola River (-85.09 
longitude, 30.01 latitude) in Gulf County, Florida, upstream 144.9 km 
(90.0 mi), including the reach known as Dead Lake, to the confluence of 
Marshall and Cowarts creeks (-85.27 longitude, 30.91 latitude) in 
Jackson County, Florida; Dry Creek from the Chipola River upstream 7.6 
km (4.7 mi) to Ditch Branch (-85.53 longitude, 30.41 latitude), Jackson 
County, Florida; Rocky Creek from the Chipola River upstream 7.1 km 
(4.4 mi) to Little Rocky Creek (-85.13 longitude, 30.68 latitude), 
Jackson County, Florida; Waddells Mill Creek from the Chipola River 
upstream 3.7 km (2.3 mi) to Russ Mill Creek (-85.29 longitude, 30.87 
latitude), Jackson County, Florida; Baker Creek from Waddells Mill 
Creek upstream 5.3 km (3.3 mi) to Tanner Springs (-85.32 longitude, 
30.83 latitude), Jackson County, Florida; Marshall Creek from the 
Chipola River upstream 13.7 km (8.5 mi) to the Alabama-Florida State 
line (-85.33 longitude, 31.00 latitude), Jackson County, Florida; and 
Big Creek from the Alabama-Florida State line upstream 7.8 km (4.9 mi) 
to Double Bridges Creek (-85.38 longitude, 31.05 latitude), Houston 
County, Alabama. The short segment of the Chipola River that flows 
underground within the boundaries of Florida Caverns State Park is not 
included within this unit.
    (ii) Note: Unit 2 map (Map 3) follows:

[[Page 32774]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.007

    (9) Unit 3. Uchee Creek, Russell County, Alabama. This is a 
critical habitat unit for the shinyrayed pocketbook.
    (i) General Description: Unit 3 includes the main stem of Uchee 
Creek

[[Page 32775]]

from its confluence with the Chattahoochee River upstream 34.2 km (21.2 
mi) to Island Creek (-85.18 longitude, 32.38 latitude), Russell County, 
Alabama, encompassing a total stream length of 34.2 km (21.2 mi).
    (ii) Note: Unit 3 map (Map 4) follows:

[[Page 32776]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.008


[[Page 32777]]


    (10) Unit 4. Sawhatchee, Sheffield Mill, and Kirkland creeks, Early 
County, Georgia. This is a critical habitat unit for the shinyrayed 
pocketbook, Gulf moccasinshell, and oval pigtoe.
    (i) General Description: Unit 4 includes the main stems of 
Sawhatchee and Kirkland creeks, and one tributary, encompassing a total 
stream length of 37.8 km (23.5 mi). Sawhatchee Creek from its 
confluence with the Chattahoochee River upstream 28.6 km (17.8 mi) to 
the powerline crossing located 1.4 km (0.87 mi) upstream of Early 
County Road 15 (-84.99 longitude, 31.32 latitude); Sheffield Mill 
Creek, the tributary, from its confluence with Sawhatchee Creek 
upstream 3.1 km (1.9 mi) to the powerline crossing located 2.3 km (1.4 
mi) upstream of Sowhatchee Road (-85.01 longitude, 31.23 latitude); 
Kirkland Creek from its confluence with the Chattahoochee River 
upstream 6.1 km (3.8 mi) to Dry Creek (-85.00 longitude, 31.13 
latitude).
    Note: Unit 4 map (Map 5) follows:

[[Page 32778]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.009

    (11) Unit 5. Upper Flint River and Swift, Limestone, Turkey, 
Pennahatchee, Little Pennahatchee, Hogcrawl, Red Oak, Line, and 
Whitewater creeks in Coweta, Crawford, Crisp, Dooly, Fayette, Macon,

[[Page 32779]]

Meriwether, Peach, Pike, Spalding, Sumter, Talbot, Taylor, Upson, and 
Worth counties, Georgia. This is a critical habitat unit for the 
shinyrayed pocketbook, Gulf moccasinshell, oval pigtoe, and purple 
bankclimber.
    (i) General Description: Unit 5 encompasses a total stream length 
of 380.4 km (236.4 mi) and includes the Flint River from the State 
Highway 27 bridge (Vienna Road) (-83.98 longitude, 32.06 latitude) in 
Dooly and Sumter counties, Georgia (the river is the county boundary), 
upstream 247.4 km (153.7 mi) through Macon, Peach, Taylor, Crawford, 
Talbot, Upson, Pike, Meriwether, and Coweta counties, to Horton Creek 
(-84.42 longitude, 33.29 latitude) in Fayette and Spalding counties, 
Georgia (the river is the county boundary); Swift Creek from Lake 
Blackshear upstream 11.3 km (7 mi) to Rattlesnake Branch (-83.84 
longitude, 31.82 latitude), Crisp and Worth counties, Georgia (the 
creek is the county boundary); Limestone Creek from Lake Blackshear, 
Crisp County, Georgia, upstream 8.8 km (5.5 mi) to County Road 89 (-
83.88 longitude, 32.04 latitude), Dooly County, Georgia; Turkey Creek 
from the Flint River upstream 21.7 km (13.5 mi) to Rogers Branch (-
83.89 longitude, 32.20 latitude), in Dooly County, Georgia; 
Pennahatchee Creek from Turkey Creek upstream 4.8 km (3 mi) to Little 
Pennahatchee Creek (-83.89 longitude, 32.10 latitude), Dooly County, 
Georgia; Little Pennahatchee Creek from Pennahatchee Creek upstream 5.8 
km (3.6 mi) to Rock Hill Creek (-83.85 longitude, 32.13 latitude), 
Dooly County, Georgia; Hogcrawl Creek from the Flint River upstream 
21.6 km (13.4 mi) to Little Creek (-83.90 longitude, 32.28 latitude), 
Dooly and Macon counties, Georgia (the creek is the county boundary); 
Red Oak Creek from the Flint River upstream 21.7 km (13.5 mi) to 
Brittens Creek (-84.68 longitude, 33.11 latitude), Meriwether County, 
Georgia; Line Creek from the Flint River upstream 15.8 km (9.8 mi) to 
Whitewater Creek (-84.51 longitude, 33.28 latitude), Coweta and Fayette 
counties, Georgia (the creek is the county boundary); and Whitewater 
Creek from Line Creek upstream 21.5 km (13.4 mi) to Ginger Cake Creek 
(-84.49 longitude, 33.42 latitude), Fayette County, Georgia.
    (ii) Note: Two maps of unit 5 (Map 6, northern part of unit 5; and 
Map 7, southern part of unit 5) follow:

[[Page 32780]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.010


[[Page 32781]]


[GRAPHIC] [TIFF OMITTED] TP06JN06.011

    (12) Unit 6. Middle Flint River and Kinchafoonee, Lanahassee, 
Muckalee, Little Muckalee, Mill, Mercer Mill Pond, Abrams, Jones, and 
Chokee creeks; Dougherty, Lee, Marion, Schley, Sumter, Terrell, 
Webster, and Worth counties,

[[Page 32782]]

Georgia. This is a critical habitat unit for the shinyrayed pocketbook, 
Gulf moccasinshell, oval pigtoe, and purple bankclimber.
    (i) General Description: Unit 6 encompasses a total stream length 
of 302.3 km (187.8 mi) and includes the Flint River from Piney Woods 
Creek (-84.06 longitude, 31.61 latitude) in Dougherty County, Georgia 
(the upstream extent of Lake Worth), upstream 39.9 km (24.8 mi) to the 
Warwick Dam (-83.94 longitude, 31.85 latitude), Lee and Worth counties, 
Georgia; Kinchafoonee Creek from its confluence with Lake Worth at the 
Lee-Dougherty county line (-84.17 longitude, 31.62 latitude), upstream 
107.6 km (66.8 mi) through Terrell and Sumter Counties, Georgia, to Dry 
Creek (-84.58 longitude, 32.17 latitude), Webster County, Georgia; 
Lanahassee Creek from Kinchafoonee Creek upstream 9.3 km (5.8 mi) to 
West Fork Lanahassee Creek (-84.50 longitude, 32.11 latitude), Webster 
County, Georgia; Muckalee Creek, from its confluence with Lake Worth at 
the Lee-Dougherty county line (-84.14 longitude, 31.62 latitude), 
upstream 104.5 km (64.9 mi) to County Road 114 (-84.44 longitude, 32.23 
latitude), Marion County, Georgia; Little Muckalee Creek, from Muckalee 
Creek in Sumter County, Georgia, upstream 7.2 km (4.5 mi) to Galey 
Creek (-84.29 longitude, 32.17 latitude), Schley County, Georgia; Mill 
Creek from the Flint River upstream 3.2 km (2 mi) to Mercer Millpond 
Creek (-83.99 longitude, 31.67 latitude), Worth County, Georgia; Mercer 
Millpond Creek from Mill Creek upstream 0.45 km (0.28 mi) to Mercer 
Mill Pond (-83.99 longitude, 31.68 latitude), Worth County, Georgia; 
Abrams Creek from the Flint River upstream 15.9 km (9.9 mi) to County 
Road 123 (-83.93 longitude, 31.68 latitude), Worth County, Georgia; 
Jones Creek from the Flint River upstream 3.8 km (2.4 mi) to County 
Road 123 (-83.96 longitude, 31.76 latitude), Worth County, Georgia; and 
Chokee Creek, from the Flint River upstream 10.5 km (6.5 mi) to Dry 
Branch Creek (-84.02 longitude, 31.89 latitude), Lee County, Georgia.
    (ii) Note: Two maps of unit 6 (Map 8, western part of unit 6; and 
Map 9, eastern part of unit 6) follow:

[[Page 32783]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.012


[[Page 32784]]


[GRAPHIC] [TIFF OMITTED] TP06JN06.013

    (13) Unit 7. Lower Flint River and Spring, Aycocks, Dry, 
Ichawaynochaway, Mill, Pachitla, Little Pachitla, Chickasawhatchee, and 
Cooleewahee creeks in Baker, Calhoun, Decatur, Dougherty, Early, 
Miller,

[[Page 32785]]

Mitchell, and Terrell counties, Georgia. This is a critical habitat 
unit for the shinyrayed pocketbook, Gulf moccasinshell, oval pigtoe, 
and purple bankclimber.
    (i) General Description: Unit 7 encompasses a total stream length 
of 396.7 km (246.5 mi) and includes the Flint River from its confluence 
with Big Slough (-84.56 longitude, 30.93 latitude), Decatur County, 
Georgia, upstream 116.4 km (72.3 mi) through Baker and Mitchell 
Counties, Georgia, to the Flint River Dam (which impounds Lake Worth) 
(-84.14 longitude, 31.60 latitude), Dougherty County, Georgia; Spring 
Creek, from its confluence with Lake Seminole at Smith Landing (-84.75 
longitude, 30.89 latitude), Decatur County, Georgia, upstream 74.2 km 
(46.1 mi) to County Road 35 (-84.78 longitude, 31.34 latitude), Early 
County, Georgia; Aycocks Creek from Spring Creek upstream 15.9 km (9.9 
mi) to Cypress Creek (-84.79 longitude, 31.15 latitude), Miller County, 
Georgia; Dry Creek from Spring Creek upstream 9.9 km (6.1 mi) to Wamble 
Creek (-84.84 longitude, 31.31 latitude), Early County, Georgia; 
Ichawaynochaway Creek from the Flint River, Baker County, Georgia, 
upstream 68.6 km (42.6 mi) to Merrett Creek (-84.58 longitude, 31.54 
latitude), Calhoun County, Georgia; Mill Creek from Ichawaynochaway 
Creek upstream 7.4 km (4.6 mi) to County Road 163 (-84.63 longitude, 
31.40 latitude), Baker County, Georgia; Pachitla Creek, from 
Ichawaynochaway Creek upstream 18.9 km (11.8 mi) to Little Pachitla 
Creek (-84.68 longitude, 31.56 latitude), Calhoun County, Georgia; 
Little Pachitla Creek from Pachitla Creek upstream 5.8 km (3.6 mi) to 
Bear Branch (-84.72 longitude, 31.58 latitude), Calhoun County, 
Georgia; Chickasawhatchee Creek from Ichawaynochaway Creek, Baker 
County, Georgia, upstream 64.5 km (40.1 mi) to U.S. Highway 82 (-84.38 
longitude, 31.74 latitude), Terrell County, Georgia; and Cooleewahee 
Creek from the Flint River upstream 15.1 km (9.4 mi) to Piney Woods 
Branch (-84.31 longitude, 31.42 latitude), Baker County, Georgia.
    (ii) Note: Two maps of unit 7 (Map 10, western part of unit 7; and 
Map 11, eastern part of unit 7) follow:

[[Page 32786]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.014


[[Page 32787]]


[GRAPHIC] [TIFF OMITTED] TP06JN06.015

    (14) Unit 8. Apalachicola River and the Chipola Cutoff and Swift 
Slough in Calhoun, Franklin, Gadsden, Gulf, Jackson, and Liberty 
counties, Florida. This is a critical habitat unit for the fat 
threeridge and purple bankclimber.

[[Page 32788]]

    (i) General Description: Unit 8 includes the main stem of the 
Apalachicola River and two of its distributaries, Chipola Cutoff and 
Swift Slough, encompassing a total stream length of 155.4 km (96.6 mi). 
The main stem of the Apalachicola River extends from the downstream end 
of Bloody Bluff Island (river mile 15.3 on U.S. Army Corps of Engineers 
Navigation Charts) (-85.01 longitude, 29.88 latitude), Franklin County, 
Florida, through Calhoun and Liberty Counties, Florida, upstream to the 
Jim Woodruff Lock and Dam (which impounds Lake Seminole) (-84.86 
longitude, 30.71 latitude), Gadsden and Jackson counties, Florida; 
Chipola Cutoff from the Apalachicola River in Gulf County, Florida, 
downstream 4.5 km (2.8 mi) to its confluence with the Chipola River, 
Gulf County, Florida; Swift Slough from the Apalachicola River, Liberty 
County, Florida, downstream 3.6 km (2.2 mi) to its confluence with the 
River Styx (-85.12 longitude, 30.10 latitude), Liberty County, Florida.
    (ii) Note: Unit 8 map (Map 12) follows:

[[Page 32789]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.016


[[Page 32790]]


    (15) Unit 9. Upper Ochlockonee River and Barnetts and West Barnetts 
creeks, and the Little Ochlockonee River in Gadsden and Leon counties, 
Florida, and Grady and Thomas counties, Georgia. This is a critical 
habitat unit for the shinyrayed pocketbook, Ochlockonee moccasinshell, 
oval pigtoe, and purple bankclimber.
    (i) General Description: Unit 9 includes the main stem of the 
Ochlockonee River upstream of Lake Talquin and three tributaries 
encompassing a total stream length of 177.3 km (110.2 mi). The main 
stem of the Ochlockonee River extends from its confluence with Gulley 
Branch (the approximate upstream extent of Lake Talquin) (-84.44 
longitude, 30.46 latitude), Gadsden and Leon counties, Florida, 
upstream 134.0 km (83.3 mi) to Bee Line Road/County Road 306 (-83.94 
longitude, 31.03 latitude), Thomas County, Georgia; Barnetts Creek from 
the Ochlockonee River upstream 20 km (12.4 mi) to Grady County Road 
170/Thomas County Road 74 (-84.12 longitude, 30.98 latitude), Grady and 
Thomas counties, Georgia; West Barnetts Creek from Barnetts Creek 
upstream 10 km (6.2 mi) to Georgia Highway 111 (-84.17 longitude, 30.98 
latitude), Grady County, Georgia; and the Little Ochlockonee River from 
the Ochlockonee River upstream 13.3 km (8.3 mi) to Roup Road/County 
Road 33 (-84.02 longitude, 31.02 latitude), Thomas County, Georgia.
    (ii) Note: Unit 9 map (Map 13) follows:

[[Page 32791]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.017

    (16) Unit 10. Lower Ochlockonee River in Leon, Liberty, and Wakulla 
counties, Florida. This is a critical habitat unit for the purple 
bankclimber.
    (i) General Description: Unit 10 encompasses a total stream length 
of

[[Page 32792]]

75.4 km (46.9 mi) and includes the main stem of the Ochlockonee River 
from its confluence with Syfrett Creek (-84.56 longitude, 30.02 
latitude), Wakulla County, Florida, upstream 75.4 km (46.9 mi) to the 
Jackson Bluff Dam (which impounds Lake Talquin) (-84.65 longitude, 
30.39 latitude), Leon and Liberty counties, Florida.
    (ii) Note: Unit 10 map (Map 14) follows:

[[Page 32793]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.018


[[Page 32794]]


    (17) Unit 11. Santa Fe River and New River in Alachua, Bradford, 
Columbia, and Union counties, Florida. This is a critical habitat unit 
for the oval pigtoe.
    (i) General Description: Unit 11 includes the main stem of the 
Santa Fe River and its tributary the New River encompassing a total 
stream length of 83.1 km (51.6 mi). The main channel of the Santa Fe 
River extends from where the river goes underground in O'Leno State 
Park (-82.57 longitude, 29.91 latitude), Alachua and Columbia counties, 
Florida, upstream 60.2 km (37.4 mi) to the powerline crossing located 
1.9 km (1.2 mi) downstream from the U.S. Highway 301 bridge (-82.18 
longitude, 29.84 latitude) in Alachua and Bradford counties, Florida; 
and the New River from its confluence with the Santa Fe River at the 
junction of Alachua, Bradford, and Union counties, Florida, upstream 
22.9 km (14.2 mi) to McKinney Branch (-82.27 longitude, 30.01 latitude) 
in Bradford and Union counties, Florida.
    (ii) Note: Unit 11 map (Map 15) follows:

[[Page 32795]]

[GRAPHIC] [TIFF OMITTED] TP06JN06.019


[[Page 32796]]


* * * * *

    Dated: May 30, 2006.
Matt Hogan,
Acting Assistant Secretary for Fish and Wildlife and Parks.
[FR Doc. 06-5075 Filed 6-5-06; 8:45 am]
BILLING CODE 4310-55-C