67512 Federal Register / Vol. 75, No. 211 / Tuesday, November 2, 2010 / Rules and Regulations 

DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

50 CFR Part 17 

[Docket No. FWS–R4–ES–2008–0104; MO 

92210–0–0008–B2] 

RIN 1018–AU88 

Endangered and Threatened Wildlife 

and Plants; Determination of 

Endangered Status for the Georgia 

Pigtoe Mussel, Interrupted Rocksnail, 

and Rough Hornsnail and Designation 

of Critical Habitat 

AGENCY: Fish and Wildlife Service, 

Interior. 

ACTION: Final rule. 

SUMMARY: We, the U.S. Fish and 

Wildlife Service (Service), list the 

Georgia pigtoe mussel (Pleurobema 

hanleyianum), interrupted rocksnail 

(Leptoxis foremani), and rough 

hornsnail (Pleurocera foremani) as 

endangered under the Endangered 

Species Act of 1973, as amended (Act). 

We also designate approximately 258 

kilometers (km) (160 miles (mi)) of 

stream and river channels as critical 

habitat for the three species, in 

Cherokee, Clay, Coosa, Elmore, and 

Shelby Counties, Alabama; Gordon, 

Floyd, Murray, and Whitfield Counties, 

Georgia; and Bradley and Polk Counties, 

Tennessee. 

DATES: This rule becomes effective on 

December 2, 2010. 

ADDRESSES: This final rule and final 

economic analysis are available on the 

Internet at http://www.regulations.gov. 

Comments and materials received, as 

well as supporting documentation used 

in preparing this final rule are available 

for public inspection, by appointment, 

during normal business hours, at the 

U.S. Fish and Wildlife Service, Jackson 

Ecological Services Field Office, 6578 

Dogwood View Parkway, Suite A, 

Jackson, MS 39213 (telephone 601–321– 

1122; facsimile 601–965–4340). 

FOR FURTHER INFORMATION CONTACT: 

Stephen Ricks, Field Supervisor, U.S. 

Fish and Wildlife Service, Jackson 

Ecological Services Field Office (see 

ADDRESSES section). If you use a 

telecommunications device for the deaf 

(TDD), call the Federal Information 

Relay Service (FIRS) at 800–877–8339. 

SUPPLEMENTARY INFORMATION: This 

document consists of: (1) A final rule to 

list as endangered the Georgia pigtoe 

mussel (Pleurobema hanleyianum), 

interrupted rocksnail (Leptoxis 

foremani), and rough hornsnail 

(Pleurocera foremani); and (2) a final 

rule to designate critical habitat for each 

of these three species. 

Previous Federal Action 

Federal actions for these species prior 

to June 29, 2009 are outlined in our 

proposed rule for these actions (74 FR 

31113). Publication of the proposed rule 

opened a 60-day comment period, 

which closed on August 28, 2009. We 

reopened the comment period from 

February 10, 2010, through March 12, 

2010, in order to announce the 

availability of and receive comments on 

a draft economic analysis (DEA), and to 

extend the comment period on the 

proposed listing and designation to 

accommodate a public hearing (75 FR 

6613). 

Public Comments 

We received comments from the 

public on the proposed listing action 

and proposed critical habitat 

designation, and, in this rule, we 

respond to these issues in a single 

comments section. Below, we present 

the listing analysis first, followed by the 

analysis for designation of critical 

habitat. 

Background 

It is our intent to discuss only those 

topics directly relevant to the listing and 

designation of critical habitat for the 

Georgia pigtoe mussel (Pleurobema 

hanleyianum), interrupted rocksnail 

(Leptoxis foremani), and rough 

hornsnail (Pleurocera foremani). For 

information on our proposed 

determination, refer to the proposed 

rule published in the Federal Register 

on June 29, 2009 (74 FR 31113). 

Georgia Pigtoe Mussel 

The Georgia pigtoe (Pleurobema 

hanleyianum) is a freshwater mussel in 

the family Unionidae. It was described 

in 1852 by Lea as Unio hanleyianum 

from the Coosawattee River in Georgia. 

The species was placed in the genus 

Pleurobema by Simpson in 1900. The 

uniqueness of the Georgia pigtoe has 

been verified both morphologically 

(Williams et al. 2008, p. 533) and 

genetically (Campbell et al. 2008, pp. 

719–721). 

The shell of the Georgia pigtoe 

reaches about 50 to 65 millimeters (mm) 

(2 to 2.5 inches (in)) in length. It is oval 

to elliptical and somewhat inflated. The 

posterior ridge is low and evenly 

rounded, when evident. The anterior 

end is rounded, while the posterior 

margin is bluntly pointed below. Dorsal 

and ventral margins are curved, and the 

beaks rise slightly above the hinge line. 

The periostracum (membrane on the 

surface of the shell) is yellowish-tan to 

reddish-brown and may have concentric 

green rings. The beak cavity is shallow, 

and the shell interior is white to dull 

bluish-white (Parmalee and Bogan 1998, 

p. 185; Williams et al. 2008, p. 533). 

Little is known about the habitat 

requirements or life history of the 

Georgia pigtoe; however, it is found in 

shallow runs and riffles with strong to 

moderate current and coarse sandgravel-cobble bottoms. Unionid mussels, 

such as the Georgia pigtoe, filter-feed on 

algae, detritus, and bacteria from the 

water column. The larvae of most 

unionid mussels are parasitic, requiring 

a period of encystment on a fish host 

before they can develop into juvenile 

mussels. The fish hosts for glochidia 

(parasitic larvae) of Georgia pigtoe are 

currently unknown. 

The Georgia pigtoe was historically 

found in large creeks and rivers of the 

Coosa River drainage of Alabama, 

Georgia, and Tennessee (Johnson and 

Evans 2000, p. 106; Williams et al., 

2008, p. 534). There are historical 

reports or museum records of the 

Georgia pigtoe from Tennessee 

(Conasauga River in Polk and Bradley 

Counties), Georgia (Conasauga River in 

Murray and Whitfield Counties, 

Chatooga River in Chatooga County, 

Coosa River in Floyd County, and 

Etowah River in Floyd County), and 

Alabama (Coosa River in Cherokee 

County, Terrapin Creek in Cherokee 

County, Little Canoe and Shoal Creeks 

in St. Clair County, Morgan Creek in 

Shelby County, and Hatchet Creek in 

Coosa County) (Florida Museum of 

Natural History Malacology Database 

(FLMNH) in litt. 2006; Gangloff 2003, p. 

45). Based on these historical records, 

the range of the Georgia pigtoe included 

more than 480 km (300 mi) of river and 

stream channels. Additional historical 

Coosa River tributary records credited to 

Hurd (1974, p. 64) (for example, Big 

Wills, Little Wills, Big Canoe, 

Oothcalooga, Holly Creeks) have been 

found to be misidentifications of other 

species (Gangloff in litt. 2006). 

In 1990, the Service initiated a status 

survey and reviewed the molluscan 

fauna of the Mobile River Basin 

(Hartfield 1991, p. 1). This led to 

extensive mollusk surveys and 

collections throughout the Coosa River 

drainage (Bogan and Pierson 1993a, pp. 

1–27; Hartfield in litt. 1990–2001). At 

all localities surveyed in the Coosa 

River drainage, the freshwater mussel 

fauna had declined from historical 

levels, and at all but a few localized 

areas, the fauna proved to be completely 

eliminated or severely reduced due to a 

variety of impacts, including point and 

nonpoint source pollution, and channel 

modifications such as impoundment. 


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Following a review of these efforts and 

observations, the Service reported 14 

species of mussels in the genus 

Pleurobema, including the Georgia 

pigtoe, as presumed extinct, based on 

their absence from collection records, 

technical reports, or museum 

collections for a period of 20 years or 

more (Hartfield 1994, p. 1). 

The Service and others continued to 

conduct surveys in the Coosa River 

drainage for mollusks (Hartfield in litt. 

2004; Williams and Hughes 1998, pp. 2– 

6; Johnson and Evans 2000, p. 106; 

Herod et al. 2001, pp. i–ii; Gangloff 

2003, pp. 11–12; McGregor and Garner 

2004, pp. 1–18; Johnson et al. 2005, p. 

1). Several freshly dead and live 

individuals of the Georgia pigtoe were 

collected during these mussel surveys in 

the Upper Conasauga River, Murray and 

Whitfield Counties, Georgia (Williams 

and Hughes 1998, p. 10; Johnson and 

Evans 2000, p. 106). Gangloff (2003, pp. 

11–12, 45) conducted mussel surveys of 

Coosa River tributaries in Alabama, 

including all known historical 

collection sites for the Georgia pigtoe, 

without relocating the species. 

McGregor and Garner (2004, p. 8) 

surveyed the Coosa River dam tailraces 

for mollusks without encountering the 

Georgia pigtoe. 

The Georgia pigtoe is currently known 

from a few isolated shoals in the Upper 

Conasauga River in Murray and 

Whitfield Counties, Georgia, and in Polk 

County, Tennessee (Johnson and Evans 

2000, p. 106; Evans 2001, pp. 33–34). 

All recent collection sites occur within 

a 43-km (27-mi) reach of the river. 

Within this reach, the Georgia pigtoe is 

very rare (Johnson and Evans 2000, p. 

106), and no population estimates are 

available. 

Interrupted Rocksnail 

The interrupted rocksnail (Leptoxis 

foremani) is a small-to-medium-sized 

freshwater snail that historically 

occurred in the Coosa River drainage of 

Alabama and Georgia. The shell grows 

to approximately 22 mm (1 in) in length 

and may be ornamented by partial 

costae (folds in the surface). The shell 

is subglobose (not quite spherical); 

thick, dark brown to olive in color; 

occasionally spotted; and generally 

covered with fine striae (longitudinal 

ridges). The spire (apex) of the shell is 

very low, and the aperture (opening) is 

large and subrotund (not quite round). 

The interrupted rocksnail, a member 

of the aquatic snail family 

Pleuroceridae, was described from the 

Coosa River, Alabama, by Lea in 1843. 

Goodrich (1922, p. 13) placed the 

species in the ‘‘Anculosa (=Leptoxis) 

picta (Conrad 1834) group,’’ which also 

included the Georgia rocksnail (Leptoxis 

downei (Lea 1868)). L. foremani was 

considered to inhabit the Lower Coosa 

River, with L. downei inhabiting the 

Upper Coosa drainage (Goodrich 1922, 

pp. 18–19, 21–23). When a rocksnail 

population was rediscovered surviving 

in the Oostanaula River, Georgia, in 

1997, it was initially identified as L. 

downei (Williams and Hughes 1998, p. 

9; Johnson and Evans 2000, pp. 45–46); 

however, Burch (1989, p. 155) had 

previously placed L. downei within L. 

foremani as an ecological variant. 

Therefore, L. downei is currently 

considered an upstream phenotype of 

the interrupted rocksnail, and L. 

foremani is recognized as the valid 

name for the interrupted rocksnail 

(Turgeon et al. 1998, p. 67; Johnson 

2004, p. 116). 

Rocksnails live in shoals, riffles, and 

reefs (bedrock outcrops) of small to large 

rivers. Their habitats are generally 

subject to moderate currents during low 

flows and strong currents during high 

flows. These snails live attached to 

bedrocks, boulders, cobbles, and gravel 

and tend to move little, except in 

response to changes in water level. They 

lay their adhesive eggs within the same 

habitat (Johnson 2004, p. 116). In a 

hatchery setting, mean clutch size for 2- 

year-old interrupted rocksnails is 

around 8.83 (3 to 18 eggs per clutch), 

and clutch size of females greater than 

3 years is 13.63 (2 to 21 eggs per clutch) 

(Johnson in litt. 2009). Interrupted 

rocksnails are currently found in shoal 

habitats with sand-boulder substrate, at 

water depths less than 50 centimeters 

(cm) (20 in), and in water currents less 

than 40 cm/second (sec) (16 in/sec) 

(Johnson 2004, p. 116). We know little 

of the life history of pleurocerid snails; 

however, they generally feed by 

ingesting periphyton (algae attached to 

hard surfaces) and biofilm detritus 

scraped off of the substrate by the snail’s 

radula (a horny band with minute teeth 

used to pull food into the mouth) 

(Morales and Ward 2000, p. 1). 

Interrupted rocksnails have been 

observed grazing on silt-free gravel, 

cobble, and boulders (Johnson 2004, p. 

116). They have survived as long as 5 

years in captivity (Johnson in litt. 

2006b). 

The interrupted rocksnail was 

historically found in colonies on reefs 

and shoals of the Coosa River and 

several of its tributaries in Alabama and 

Georgia. The range of the rocksnail 

formerly encompassed more than 800 

km (500 mi) of river and stream 

channels, including the Coosa River 

(Coosa, Calhoun, Cherokee, Elmore, 

Etowah, Shelby, St. Clair, and Talladega 

Counties), Lower Big Canoe Creek (St. 

Clair County), and Terrapin Creek 

(Cherokee County) in Alabama; and the 

Coosa and Lower Etowah Rivers (Floyd 

County), the Oostanaula River (Floyd 

and Gordon Counties), the Coosawattee 

River (Gordon County), and the 

Conasauga River (Gordon, Whitfield, 

and Murray Counties) in Georgia 

(Goodrich 1922, pp. 19, 21; Johnson 

2004, p. 116; FLMNH in litt. 2006). 

Snail surveys conducted within the 

historical range of the interrupted 

rocksnail (Bogan and Pierson 1993a, pp. 

1–27; Williams and Hughes 1998, pp. 1– 

21) resulted in the collection of only a 

single live specimen from the 

Oostanaula River, Floyd County, 

Georgia, during 1997 (Williams and 

Hughes 1998, p. 9). Intensive surveys of 

the Oostanaula, Coosa, Coosawattee, 

Etowah, and Conasauga Rivers since 

1999 have located the species in about 

12 km (7.5 mi) of the Oostanaula River 

upstream of the Gordon and Floyd 

County line (Johnson and Evans 2000, 

pp. 45–46; Johnson and Evans 2001, pp. 

2, 25). A captive colony was maintained 

at the Tennessee Aquarium Research 

Institute (TNARI) from 2000 through 

2005 for study and propagation. In 

coordination with TNARI and the 

Service, the Alabama Department of 

Conservation and Natural Resources 

(ADCNR) developed a plan and strategy 

to reintroduce interrupted rocksnails 

from the TNARI colony into the Coosa 

River above Wetumpka, Elmore County, 

Alabama (ADCNR 2003, pp. 1–4). In 

2003, 2004, and 2005, approximately 

3,200, 1,200, and 3,000 juvenile snails, 

respectively, from the TNARI culture 

were released into the Lower Coosa 

River (ADCNR 2004, p. 33; Johnson in 

litt. 2005a). In 2005, ADCNR established 

the Alabama Aquatic Biodiversity 

Center (AABC) at the Marion State Fish 

Hatchery for the culture of imperiled 

mollusk species, and the interrupted 

rocksnail TNARI colony was transferred 

to that facility. 

Following its rediscovery, the 

interrupted rocksnail population size on 

shoals in the Oostanaula River declined 

from a high of 10 to 45 snails per square 

meter (m2) (1.2 square yards (yd2)) in 

1999 (Johnson and Evans 2001, p. 22) to 

only 20 snails found during 6 searchhours in 2004 (Johnson in litt. 2003, 

2004). The cause of decline was 

suspected to be some form of water 

contamination (Johnson in litt. 2003, 

2004; Hartfield in litt. 2006). A July 

2006 search for adults to use as hatchery 

stock failed to locate any rocksnails in 

more than 2 search-hours (Hartfield in 

litt. 2006). However, a subsequent 

search in August 2006 under lower flow 

conditions resulted in the location of 89 

snails in 4 search-hours at one shoal, 


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and 2 rocksnails in 4 search-hours at 

another shoal (Johnson in litt. 2007a). 

Since their reintroduction into the 

Lower Coosa River of Alabama, a few of 

the 2003 hatchery-cultured interrupted 

rocksnails were observed in the vicinity 

of the release site in 2004 (Johnson in 

litt. 2005c). An alternative site was 

selected for release in August 2005, and 

18 snails were located 3 months 

following release (Pierson in litt. 2005). 

During a 40-minute search of this 

release area in 2006, two interrupted 

rocksnails were found (Johnson in litt. 

2007b). Observations of only small 

numbers of reintroduced snails may be 

due to habitat size and dispersal, low 

fecundity of the species, predation, 

reproductive failure due to dispersal, or 

habitat disturbance (Johnson in litt. 

2005b). 

Rough Hornsnail 

The rough hornsnail’s (Pleurocera 

foremani) shell is elongated, pyramidal, 

and thick. Growing to about 33 mm (1.3 

in.) in length, the shell has as many as 

nine yellowish-brown whorls. The 

aperture is elongated, angular, 

channeled at the base, and usually 

white inside. The presence of a double 

row of prominent nodules or tubercles 

on the lower whorls above the aperture 

is the most distinctive feature that 

separates it from other hornsnails 

(Tryon 1873, p. 53). These tubercles, 

along with the size and shape of the 

shell, distinguish the species from all 

other pleurocerid snails (Elimia spp., 

Leptoxis spp., Pleurocera spp.) in the 

Mobile River Basin. In a hatchery 

setting, however, the distinctive double 

row of tubercules do not appear until 

the second year of life (5 to 7 mm shell 

width) (Johnson in litt. 2009). 

The rough hornsnail is a member of 

the aquatic snail family of 

Pleuroceridae. The species was 

described in 1843 by Lea as Melania 

foremanii (=foremani) (Tryon 1873, p. 

52). It was later placed in the genus 

Pleurocera by Tryon (1873, p. 52), who 

noted that P. foremani closely 

resembled species of that genus. 

Goodrich (1935, p. 3) reported a 

variation of a species of Pleurocera in 

the Cahaba River that resembled 

foremani, but later identified that 

variant as a ‘‘mutation’’ or form of brook 

hornsnail (P. vestitum) (Goodrich 1941, 

p. 12). This variant, however, is no 

longer extant in the Cahaba River 

(Bogan and Pierson 1993b, p. 12; Sides 

2005, pp. 21–22, 28). Goodrich (1944, p. 

43) considered that the Coosa River P. 

foremani might also be eventually found 

to be simply a variant of smooth 

hornsnail (P. prasinatum), another more 

widely distributed species in the Coosa 

River. 

In a recent dissertation on the 

systematics of the Mobile River Basin 

Pleurocera, the rough hornsnail was 

found to be both morphologically and 

genetically distinct from other species 

in the genus (Sides 2005, pp. 26, 127). 

This analysis also found that the rough 

hornsnail was genetically more closely 

allied to a co-occurring species in the 

genus Elimia, and concluded that it 

should be recognized as Elimia 

foremani (Sides 2005, pp. 26–27). 

Although the Sides (2005, pp. 26–27) 

study provides some evidence that this 

species should be placed in the genus 

Elimia, this taxonomic change has not 

been formally peer-reviewed and 

published. Therefore, for the purposes 

of this action, we will continue to use 

currently recognized nomenclature for 

the rough hornsnail (Pleurocera 

foremani). 

Rough hornsnails are primarily found 

on gravel, cobble, bedrock, and mud in 

moderate currents. They have been 

collected at depths of 1 m (3.3 ft) to 3 

m (9.8 ft) (Hartfield 2004, p. 132). The 

species appears to tolerate low-tomoderate levels of silt deposition (Sides 

2005, p. 127). Little is known regarding 

the life-history characteristics of this 

species. Snails in the genus Pleurocera 

generally lay their eggs in a spiral 

arrangement on smooth surfaces (Sides 

2005, pp. 26–27), whereas Elimia snails 

generally lay eggs in short strings (P. 

Johnson pers. comm. 2006). Although 

some attempts to induce rough 

hornsnails to lay eggs in captivity have 

been unsuccessful (Sides 2005, p. 27), 

others have observed females laying 

eggs individually or in short ‘‘strips’’ (3 

to 10 eggs) during late April into July 

(Johnson in litt. 2009). Cultured rough 

hornsnails have become reproductively 

active in their second year (Johnson in 

litt. 2009). Some adult individuals 

collected from the wild have survived in 

captivity for 3 years, suggesting a life 

span of 4 to 5 years (Garner in litt. 2009, 

Johnson in litt. 2009). 

The rough hornsnail is endemic to the 

Coosa River system in Alabama. 

Goodrich (1944, p. 43) described the 

historical range as the Coosa River 

downstream of the Etowah River and at 

the mouths of a few tributaries. The 

Etowah River enters the Coosa River in 

Floyd County, Georgia; however, there 

are no known museum or site-specific 

records of the rough hornsnail that 

validate its range into the State of 

Georgia (Johnson in litt. 2006a). 

Historical museum records of the rough 

hornsnail in the Coosa River (FLMNH in 

litt. 2006, and elsewhere) indicate that 

they occurred from Etowah, St. Clair, 

Shelby, Talladega, and Elmore Counties, 

Alabama, a historical range of 

approximately 322 river km (200 river 

mi). There are also historical museum 

records of this species from nine Coosa 

River tributaries in Alabama, including 

Big Wills Creek in Etowah County; 

Kelly, Big Canoe, and Beaver Creeks in 

St. Clair County; Ohatchee Creek in 

Calhoun County; Choccolocco and 

Peckerwood Creeks in Talladega 

County; Yellowleaf Creek in Shelby 

County; and Yellow Leaf Creek in 

Chilton County (FLMNH in litt. 2006). 

The rough hornsnail is currently 

known to occur at two locations: Lower 

Yellowleaf Creek in Shelby County, 

Alabama; and the Lower Coosa River 

below Wetumpka Shoals in Elmore 

County, Alabama (Sides 2005, p. 40). 

There are also museum records of the 

species from Wetumka Shoals in the 

early 1990s (FLMNH in litt. 2006); 

however, the species has not been 

collected from this shoal reach in recent 

surveys (Johnson 2002, pp. 5–9). 

Yellowleaf Creek is a moderately sized 

stream where rough hornsnails were, 

until recently, only known from about a 

50-m (55-yd) length of the stream. At 

this location, rough hornsnails occur at 

densities of 8 to 32 per m2 (1.2 per yd2) 

(Pierson in litt. 2006). Following 

publication of the proposed rule (74 FR 

31113, June 29, 2009), an intensive 

survey of Yellowleaf Creek extended the 

range of rough hornsnails in this stream 

to about 1.6 km (1 mi) above and below 

the previously known site (Powell in 

litt. 2009). The Lower Coosa River is a 

large river channel where rough 

hornsnails have recently been found in 

two discrete areas (Hartfield pers. obsv. 

2001, Crow in litt. 2008). No 

quantitative estimates have been made 

at these sites; however, at one site, 

rough hornsnail numbers were 

estimated at 300 to 400 individuals 

(Crow in litt. 2008). Searches of 

unimpounded reaches of the Coosa 

River and the lower portions of 

tributaries to the Coosa River have failed 

to locate the species elsewhere (Bogan 

and Pierson 1993a, pp. 1–27; Garner, 

pers. comm. 2005; Hartfield in litt. 

2006). The two known surviving 

populations are separated by three 

impoundments and about 113 km (70 

mi) of unsuitable, impounded channel 

habitat. 

Summary of Comments and 

Recommendations 

During the open comment periods for 

the proposed rule (74 FR 31113), draft 

economic analysis, and public hearing 

(75 FR 6613), we requested all 

interested parties submit comments or 

information concerning the proposed 


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listing and designation of critical habitat 

for the three mollusks. We contacted all 

appropriate State and Federal agencies, 

county governments, elected officials, 

scientific organizations, and other 

interested parties and invited them to 

comment. We also published newspaper 

notices inviting public comment in the 

following newspapers: Cherokee County 

Herald, Centre, AL; Daily Home, 

Talladega, AL; The Wetumpka Herald, 

Wetumpka, AL; Chatsworth Times, 

Chatsworth, GA; Rome News Tribune, 

Rome, GA; The Daily Citizen, Dalton, 

GA; The Calhoun Times, Calhoun, GA; 

Cleveland Daily Banner, Cleveland, TN; 

and Polk County News, Benton, TN. 

We directly notified and requested 

comments from all affected States. The 

State of Alabama provided additional 

records of one species. None of the 

States expressed a position on the 

actions. During the comment periods, 

we received a total of 16 comments from 

one State agency, two Federal agencies, 

eight groups, and three individuals. At 

the public hearing, we received three 

oral comments. A transcript of the 

hearing is available for inspection at the 

Jackson, Mississippi Ecological Services 

Field Office (see ADDRESSES section). 

Peer Review 

In accordance with our peer review 

policy published in the Federal Register 

on July 1, 1994 (59 FR 34270), we 

requested the expert opinions of four 

knowledgeable individuals with 

expertise on freshwater mollusks, the 

Mobile River Basin, and conservation 

biology principles. The purpose of such 

review is to ensure that the designation 

is based on scientifically sound data, 

assumptions, and analyses, including 

input of appropriate experts and 

specialists. 

We received written responses from 

three of the peer reviewers. All peer 

reviewers stated that the proposal 

included a thorough and accurate 

review of the available scientific and 

commercial data on these mollusks and 

their habitats. One peer reviewer 

provided additional details and minor 

corrections on the shell descriptions of 

the interrupted rocksnail and rough 

hornsnail. Two reviewers provided 

information on clutch size and life span 

of rough hornsnail. One reviewer noted 

the collection of rough hornsnail on 

mud bottoms, and recommended 

including this in the discussion of the 

physical and biological features that are 

essential to the conservation of that 

species (primary constituent elements 

(PCEs)). This information provided by 

the reviewers has been incorporated 

into the appropriate sections of this 

final rule. One peer reviewer suggested 

additional stream reaches that could be 

designated as critical habitat for each of 

the three species. These suggestions are 

discussed below. 

We reviewed all comments received 

for substantive issues and new data 

regarding the three mollusks, their 

critical habitats, and the draft economic 

analysis. Written comments and oral 

statements presented at the public 

hearing and received during the 

comment periods are addressed in the 

following summary. For readers’ 

convenience, we have combined similar 

comments into single comments and 

responses. 

Peer Reviewer Comments 

(1) Comment: The Georgia pigtoe 

survives in only 3 to 5 miles (4.8 to 8 

kilometers) of the Conasauga River, and 

has been extirpated from more than 99.9 

percent of its historic range. 

Our response: Over the past 20 years, 

the Georgia pigtoe has been collected 

from two localized collection sites on 

the Conasauga River, one at each 

extreme of a 43-km (27-mi) reach of the 

river. We have considered this entire 

reach as occupied because of the 

similarity of habitat within this reach, 

and the potential of the species to occur 

within any portion of the reach. 

(2) Comment: Big Canoe, 

Choccolocco, and Weogufka Creeks 

should be designated as critical habitat 

for Georgia pigtoe. 

Our response: While Big Canoe, 

Choccolocco, and Weogufka Creeks are 

within the geographical range of the 

Georgia pigtoe and appear to be suitable 

for the species, we are unaware of any 

verified historical records of the species 

from these three tributaries. Although 

we have not included these areas as 

critical habitat in this final rule, they are 

within the geographical range of the 

species and may prove to be important 

in the future to the conservation of the 

species. 

(3) Comment: Choccolocco, Hatchet, 

and Terrapin Creeks should be 

designated as critical habitat for the 

interrupted rocksnail. 

Our response: Choccolocco, Hatchet, 

and Terrapin Creeks are within the 

geographical area historically occupied 

by the interrupted rocksnail. Most 

museum specimens and historical 

records of interrupted rocksnail were 

from the mainstem Coosa River and 

larger tributaries (Oostanaula, 

Coosawhattee, Conasauga, and Etowah 

Rivers), and we were able to document 

records of interrupted rocksnail from 

the lower reach of Terrapin Creek. It is 

also likely that some populations 

extended into the lower reaches of some 

other tributaries. However, this species 

requires moderate to high stream flow, 

and the lower reaches of Choccolocco 

and Hatchet Creeks have little flow, due 

to embayment by Coosa River reservoirs. 

As a result, we did not include these 

areas as critical habitat in this final rule. 

Lower Terrapin Creek continues to 

experience natural flow, and will be 

available to colonization if the species is 

successfully reintroduced into Unit IR 1. 

(4) Comment: Recent sampling has 

extended the range of the rough 

hornsnail in Yellowleaf Creek. 

Our response: Following publication 

of the proposed rule and closure of the 

first comment period, a snail survey of 

lower Yellowleaf Creek was conducted 

by biologists from the Service, ADCNR, 

and Alabama Power Company. The 

rough hornsnail was found at several 

sites within the upper and lower limits 

of the proposed critical habitat. The 

information that the rough hornsnail 

currently inhabits all of the area within 

Unit RH 2, Yellowleaf Creek, has been 

incorporated into the Background and 

Critical Habitat sections of this final 

rule. 

(5) Comment: Choccolocco Creek, 

Kelly Creek, and the Coosa River below 

Logan Martin Dam in the vicinity of the 

confluence of Kelly Creek should be 

included as critical habitat for the rough 

hornsnail. 

Our response: We identified two areas 

with greatest conservation potential for 

the rough hornsnail, Lower Coosa River 

(Unit IR 1) and Yellowleaf Creek (Unit 

IR 2), as both of these units contain 

unoccupied habitat adjacent to occupied 

areas, with the potential of natural 

dispersal and recolonization. Lower 

Choccolocco Creek was considered to 

have minimal conservation potential for 

the species at this time because it is 

embayed by Logan Martin Lake, and is 

on the Alabama 303(d) list of impaired 

waters. Kelly Creek, and the short 

associated reach of the Coosa River, is 

remote from currently occupied areas. 

Although this area was not included in 

the critical habitat designation for rough 

hornsnail, it may become important for 

the conservation of the species at some 

point in the future. 

Comments from States 

(6) Comment: There are records of 

Georgia pigtoe from Kelly, Big Canoe, 

and Choccolocco Creeks that were not 

acknowledged in the historical 

distribution. 

Our response: It is probable that any 

large Coosa River tributary may have 

supported historical populations of the 

Georgia pigtoe at some time in the past. 

We have relied on published records 

and museum specimens to confirm the 

species’ historical presence for purposes 


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of this critical habitat designation. Some 

historical Coosa River tributary records, 

however, have been found to be 

misidentifications of other closely 

related species, and we were unable to 

document any historical records of 

Georgia pigtoe from Kelly, Big Canoe, 

and Choccolocco Creeks. 

Public Comments 

(7) Comment: The conclusions 

supporting the proposed designation of 

the critical habitat units are not 

supported by data or sound science. The 

Act requires the Service to refrain from 

designating critical habitat when the 

biological needs of the species are not 

sufficiently well known to permit 

identification of an area as critical 

habitat (citing Cape Hatteras Access 

Preserv. Alliance v. U.S. Dept. Int., 344 

F. Supp. 2nd 108, 123 (D.D.C. 2004)). 

Our response: We determined that, 

based on the best available scientific 

and commercial data, sufficient 

information is available to identify 

physical and biological features 

essential to the conservation of the 

species and specific areas that meet the 

definition of critical habitat (see Primary 

Constituent Elements (PCEs) section). 

In the case cited by the commenter, 

the Service had not identified any 

features essential to the conservation of 

the species (primary constituent 

elements (PCEs)) within some portions 

of a broad critical habitat designation for 

piping plover, but argued that 

designation was proper because PCEs 

would likely be found in the future. The 

court found that this was ‘‘beyond the 

pale of the [Act].’’ In contrast, in both 

the proposed and this final rule, we 

identified PCEs within the designated 

habitat (see Criteria Used To Identify 

Critical Habitat, and Critical Habitat 

Designation sections). Therefore, we 

have complied with the requirements of 

the Act. 

(8) Comment: The Service exceeded 

the statutory basis for proposing to 

designate Units GP2 and IR1 as 

unoccupied critical habitat by including 

the potential for minimum flows as 

baseline criteria for the establishment of 

the units. The Act does not provide for 

special management or operational 

considerations for proposed units that 

are presently unoccupied by target 

species (citing Cape Hatteras Access 

Preserv. Alliance v. U.S. Dept. Int., 344 

F. Supp. 2nd 108, 123 (D.D.C. 2004)). 

Our response: In the case cited by the 

commenter, the Service included areas 

that clearly did not contain PCEs within 

a broad critical habitat designation for 

piping plover. The Court determined 

that the Service must show that PCEs, 

which may in the future require special 

consideration or management, are found 

on the areas it designated as critical 

habitat. 

In this designation, when considering 

areas as critical habitat, we assessed 

whether the areas contained features 

that are essential to the conservation of 

the species (PCEs) and whether those 

features may require special 

management considerations or 

protections. The presence of one or 

more PCE was documented (see Critical 

Habitat Designation section) in all of the 

stream reaches designated as 

unoccupied critical habitat for the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail. We use the 

language ‘‘* * * one or more * * *’’ in 

recognition that all areas essential to the 

conservation of a species may not 

contain all PCEs, based on the biology 

of the species. For example, a species 

may require one area for feeding and 

growing, another for reproduction or 

roosting, and still other areas for passage 

between feeding and growing areas. So 

while all areas may not contain the 

same constituent elements, they may be 

important at some life stage or during 

some time of the year and collectively 

they are essential to the conservation of 

the species. 

Unit GP 2 for the Georgia pigtoe 

includes the lower reach of Terrapin 

Creek, downstream to its confluence 

with the Coosa River, and the Coosa 

River from Weiss Dam downstream to a 

point below the confluence of Terrapin 

Creek in Cherokee County, Alabama (see 

Critical Habitat Designation, Unit GP 2, 

below). All five PCEs identified for 

Georgia pigtoe are present in Terrapin 

Creek and in the Coosa River portion of 

Unit GP 2 below the confluence of 

Terrapin Creek. Unit IR 1 for the 

interrupted rocksnail includes the Coosa 

River channel between Weiss Dam to a 

point below the confluence of Terrapin 

Creek (see Critical Habitat Designation, 

Unit IR 1, below). All four PCEs 

identified for the interrupted rocksnail 

are present in the Coosa River portion 

of the Unit below Terrapin Creek. Two 

of the five PCEs for Georgia pigtoe, and 

two of the four PCEs for interrupted 

rocksnail, are currently present in the 

Coosa River portion of the units 

between Weiss Dam and the confluence 

of Terrapin Creek. Minimum flows are 

projected to be released from Weiss Dam 

as part of a Federal Energy Regulatory 

Commission relicensing agreement in 

the near future that will restore the 

remaining PCEs for both of these species 

in this portion of the reach, but that was 

not the sole basis for this designation. 

(9) Comment: It is unreasonable to 

designate unoccupied areas adjacent to 

current populations as critical habitat in 

light of the Service’s lack of knowledge 

of specific habitat requirements. 

Our response: All recent records of 

the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail are 

extremely localized. Because rare 

aquatic snails and mussels can be 

difficult to locate, where more than one 

occurrence record of a particular species 

was found within a stream reach, we 

considered the entire reach between the 

uppermost and lowermost locations as 

occupied habitat. We then considered 

the adequacy of occupied habitat for 

conservation of the species, and 

determined that designating only 

occupied habitat would not be sufficient 

to conserve each of these species (see 

Criteria Used To Identify Critical 

Habitat section). For identification of 

unoccupied areas essential to the 

conservation of the species, we 

established six criteria for their 

consideration (see Stream Reaches Not 

Currently Occupied section), including 

the presence of PCEs. One of these 

criteria prioritized stream reaches 

adjacent to currently occupied areas. 

These reaches are similar in stream size, 

geology, and water quality to adjacent 

occupied areas, and we believe that it is 

reasonable and cost effective to protect 

areas available for natural dispersal and 

reoccupation. 

(10) Comment: Critical habitat 

designation of currently uninhabited 

areas remote from occupied areas (Units 

GP 2, GP 3, IR 1, IR 3) is not supported 

by the record, and would be arbitrary 

and capricious because there is no 

analysis, data, or discussion whether 

released, captive-bred stock can become 

self-sustaining. 

Our response: Many endangered 

aquatic mollusks are so rare that 

relocations are not an option (National 

Native Mussel Conservation Committee 

1997, p. 8). However, freshwater 

mussels, including endangered and 

threatened species, have been relocated 

with some success from areas of 

disturbance into new habitats (Cope and 

Waller 1995, p. 147; U.S. Fish and 

Wildlife Service 2004, p. 4). Attempts to 

relocate imperiled mollusks from areas 

of natural abundance into historical 

habitats have also been successful (e.g., 

Ahlstedt 1991, p. 141). Aquatic mollusk 

hatchery husbandry is a relatively new 

science. However, much progress has 

been made over the past 2 decades and 

hatchery propagation of aquatic 

mollusks is now a viable conservation 

tool (e.g., Freshwater Mollusk 

Conservation Society 2006, p. 1–13). 

Reintroduction with hatchery 

propagules is recognized as a primary 

recovery task for rare aquatic species in 

the Mobile River Basin Aquatic 


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Ecosystem Recovery Plan (U.S. Fish and 

Wildlife Service 2000, p. 30). As noted 

in the Background, above, the 

interrupted rocksnail has been 

successfully propagated and produced 

in sufficient numbers for limited 

releases. Another closely related snail, 

the plicate rocksnail, has been 

propagated, and attempts to reintroduce 

the species into historical habitat in 

Alabama have shown success in terms 

of survival and natural recruitment in 

the reintroduced population (Johnson in 

litt. 2008). The available information 

indicates that the Georgia pigtoe and 

interrupted rocksnail cannot be 

conserved without extending the 

species’ range into historically occupied 

areas (see Criteria Used To Identify 

Critical Habitat section). Reintroduction 

using hatchery reared offspring is 

currently the only option to achieve this 

conservation benchmark. 

(11) Comment: The Act and its 

application in designating critical 

habitat is unconstitutional in light of the 

clear limitations on the use of Federal 

power in the property clause of the 

Constitution’s Fifth Amendment 

(‘‘* * * private property [shall not] be 

taken for public use, without just 

compensation’’). 

Our response: The designation of 

critical habitat, in and of itself, has no 

legal effect on property rights or 

constitute a physical or regulatory 

‘‘taking’’ of real estate property. Critical 

habitat does not preclude property use; 

rather, it only affects Federal 

authorization or funding of projects that 

may adversely modify critical habitat. In 

the event such a finding is made in a 

section 7 consultation with the Federal 

funding or authorizing agency, the 

Service is required to identify 

reasonable and prudent project 

alternatives. Exemption procedures 

under the Act provide sufficient 

opportunity to accomplish the Service’s 

statutory mandates without precluding 

compatible use of private property. 

Therefore, critical habitat designation, 

by itself, does not affect a taking of 

private property. 

(12) Comment: FWS should conduct 

an analysis under the National 

Environmental Policy Act (NEPA) (42 

U.S.C. 4321 et seq.) prior to listing and 

designating critical habitat. 

Our response: Environmental 

assessments and environmental impact 

statements, as defined under NEPA, are 

not required for regulations enacted 

under section 4 of the Act (see 48 FR 

49244, October 25, 1983). The FWS has 

determined that, outside of the 

jurisdiction of the United States Court of 

Appeals for the Tenth Circuit, a NEPA 

analysis is not required for critical 

habitat designation. 

(13) Comment: Interrupted rocksnails 

in Alabama (Unit IR 3) that are covered 

by the proposal are not wild, naturally 

occurring species. The reintroduced 

colony is not reproducing and is not 

viable. 

Our response: Any interrupted 

rocksnails currently surviving in Unit IR 

3 are surviving individuals from 

releases made by ADCNR in 2003 

through 2005, or their offspring. While 

there is currently no evidence that 

natural recruitment of rocksnails has 

occurred on the shoal since the release, 

we are unable to confirm their 

extirpation from the site. Including this 

single shoal in the designation alerts 

Federal action agencies to the species’ 

potential presence. 

(14) Comment: The determination that 

reintroduction of interrupted rocksnail 

into Units IR 1 and IR 3 is essential to 

its conservation is not supported by the 

record and is arbitrary and capricious. 

Our response: Under the Summary of 

Factors Affecting the Species section, 

below, we note that the surviving 

populations of each species are small, 

extremely localized, isolated, and 

vulnerable to habitat modification, toxic 

spills, progressive degradation from 

land surface runoff, and catastrophic 

changes to their habitats from flood 

scour and drought. Under the Criteria 

Used To Identify Critical Habitat 

section, we discuss areas currently 

occupied by the species, the species’ 

limited extent, their vulnerability to 

random events, and the inability of 

these species to naturally recolonize 

historically occupied areas that might 

now support them. This information 

was used to determine that the 

designation of unoccupied critical 

habitat is essential to the conservation 

of the species. Also under the Criteria 

Used To Identify Critical Habitat 

section, we discuss our process for 

assessing the potential of historically 

occupied stream reaches as unoccupied 

critical habitat, the criteria we used to 

determine if they were essential to the 

conservation of the species, and the 

PCEs currently present in each stream 

reach considered for designation as 

critical habitat. Our reasons for 

designating Units IR 1 and IR 3 as 

critical habitat for the interrupted 

rocksnail are discussed in some detail in 

the Critical Habitat sections, below. 

These include the presence of PCEs in 

both units, the presence of species in 

both units that are closely related to the 

interrupted rocksnail and require 

similar PCEs, improvements in water 

quality and quantity over the past 2 

decades, and the potential of these two 

stream reaches for reoccupation by the 

interrupted rocksnail through 

reintroduction efforts. Based on this 

analysis, and our review of the best 

available scientific information, all 

unoccupied stream reaches included in 

the critical habitat designations for each 

of these three species, including Units 

IR 1 and IR 3, are essential to their 

conservation. Units IR 1 and IR 3, 

however, are remote and separated by 

one (Unit IR 1) or more (Unit IR 3) 

impoundments from the only surviving 

population of the interrupted rocksnail 

in the Oostanaula River. Therefore, 

conservation of the interrupted 

rocksnail will require reintroduction of 

the species into Unit IR 1, and 

appropriate areas in Unit IR 3. 

(15) Comment: Smaller and more 

protected tributaries should be 

considered for reintroductions of the 

interrupted rocksnail. 

Our response: While smaller and 

more protected tributaries are within the 

historical geographical range of the 

interrupted rocksnail, and may become 

important to its conservation, we relied 

on documented historically occupied 

areas for the purposes of preparing this 

critical habitat designation for the 

reasons discussed above (see our 

response to Comment 6, above). 

(16) Comment: There are no rough 

hornsnails in the habitat proposed to be 

designated as critical habitat. 

Our response: Rough hornsnails were 

documented from Unit RH 1, Coosa 

River above the Fall Line during the 

1990s (FLMNH in litt. 2006), and have 

most recently been documented from 

two locations below the Fall Line 

(Hartfield in litt. 2001, Crow in litt. 

2008). In Unit RH 2, Yellowleaf Creek, 

rough hornsnails occur throughout the 

designated reach (see Background 

section). 

(17) Comment: The Service appears to 

be proposing to designate critical habitat 

on the chance a particular species might 

move into it at some point in the future. 

What happens to unoccupied critical 

habitat if a species does not naturally 

repopulate the area? 

Our response: With appropriate 

management, we hope to conserve the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail within currently 

occupied areas and promote natural 

dispersal into unoccupied areas 

adjacent to occupied reaches. We 

recognize that there is little chance of 

natural dispersal of the Georgia pigtoe 

and interrupted rocksnail into the 

designated unoccupied areas that are 

remote from surviving populations due 

to the presence of multiple dams and 

large areas of impounded (and thus 

unsuitable) channels. However, newly 


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developed information and technology 

are promising for successful 

reintroductions of hatchery-reared 

individuals into these areas. 

(18) Comment: What happens to 

critical habitat if a species becomes 

definitively extinct? 

Our response: The Act requires us to 

conduct 5-year reviews on the status of 

listed species. If a species is determined 

to be extinct, it can be removed from the 

List of Endangered and Threatened 

Wildlife through the formal rulemaking 

process. If a species is removed from the 

List due to extinction, areas that have 

been designated as critical habitat for 

that species will no longer be subject to 

the section 7 consultation requirements 

of the Act. 

(19) Comment: The Service did not 

consider whether the reintroduced 

population of interrupted rocksnail 

present in Unit IR 3 should be 

designated as experimental under 

section 10(j) of the Act. Listing and 

designating critical habitat for 

reintroduced species is bad public 

policy, and is an attempt to circumvent 

the purposes of section 10(j) of the Act. 

Our response: Under section 10(j), the 

Secretary of the Department of the 

Interior can designate reintroduced 

populations established outside the 

species’ current range, but within its 

historical range, as ‘‘experimental.’’ 

Based on the best available information, 

we must determine whether an 

experimental population is ‘‘essential’’ 

or ‘‘nonessential’’ to the continued 

existence of the species. Experimental 

populations that are essential to the 

continued existence of the species are 

treated as a threatened species, and the 

Secretary may promulgate regulations 

under section 4(d) of the Act. 

Experimental populations that are not 

essential to the continued existence of 

the species are treated as species 

proposed for listing. Section 10(j)(C)(ii) 

prohibits designation of critical habitat 

only for experimental populations that 

are not essential to the continued 

existence of the species. 

Within this rule, we reviewed the 

status of the interrupted rocksnail, its 

historical and current range, the threats 

affecting the conservation of the species, 

and the areas available for its 

conservation. We used this information 

to identify Unit IR 3 as an area essential 

for the conservation of the interrupted 

rocksnail, and we are designating it as 

critical habitat (see Unit IR3: Lower 

Coosa River, Elmore County, Alabama, 

below). 

(20) Comment: The reintroduction of 

the interrupted rocksnail into Alabama 

prior to the proposed listing did not 

allow for consideration of the Act’s 

reintroduction provisions, or alert the 

public to the Service’s consideration of 

experimental status. 

Our response: As noted in our 

response to Comment 13, above, the 

reintroduction of the interrupted 

rocksnail into the lower Coosa River, 

Alabama, was a State action conducted 

under State regulations. The public was 

notified by the State through a press 

release and publication of the 

reintroduction in public media. 

(21) Comment: The Service recognizes 

(in the 2003 draft, Freshwater Mussels 

and Snails of the Mobile River Basin: 

Plan for the Controlled Propagation, 

Augmentation, and Reintroduction) that 

reintroductions of hatchery mollusk 

propagules is experimental in nature. 

Therefore, they should be designated as 

experimental populations under section 

10(j) of the Act. 

Our response: The 2003 draft plan for 

controlled propagation was addressed to 

scientists, institutions, and agencies 

contemplating propagation of mollusks 

as a management strategy. In 2003, 

mollusk propagation was an emerging 

science and technology. This was the 

first propagation plan developed for 

mollusk species, and sought to alert the 

intended audience (i.e., scientists and 

State and Federal agencies 

contemplating propagation of mollusks) 

of the need for rigorous documentation 

and monitoring. The use of the term 

‘‘experimental’’ in this document has no 

direct connection to the term’s use 

under section 10(j) of the Act, where it 

is a term used to identify reintroduced 

populations of listed species outside of 

their geographical range that may 

receive specific exemptions from 

section 9 of the Act. 

(22) Comment: The lack of 

experimental population designation for 

interrupted rocksnails (in IR 3) may 

cause serious negative impacts to 

landowners, businesses, and users of the 

Coosa River, through limiting 

landowners’ ability to manage 

properties and creating uncertainty for 

landowners and waterway users. 

Our response: Unit IR 3 is occupied 

by the federally protected tulotoma snail 

and fine-lined pocketbook, which are 

currently subject to the section 7 

consultation provisions, as well as the 

section 9 prohibitions, of the Act. Apart 

from limited hydropower flow 

modifications to reduce take of tulotoma 

snail by the Alabama Power Company, 

we are unaware of any negative impacts 

to landowners, businesses, or users of 

this reach of the Coosa River due to the 

presence of mollusk species currently 

protected under the Act. It is not 

anticipated that this listing and the 

reintroduction of interrupted rocksnails 

will impair legal activities in the unit by 

landowners and waterway users. 

(23) Comment: The proposed critical 

habitat designation of unoccupied 

habitat for the interrupted rocksnail 

should be withdrawn. 

Our response: We are required by 

section 4(a) of the Act to designate 

critical habitat at the time a species is 

listed, and to designate unoccupied 

areas as critical habitat when we 

determine that the best available 

scientific data demonstrate that the 

designation of that area is essential to 

the conservation needs of the species 

(see Critical Habitat section). We 

determined that Unit IR 1 and 

unoccupied portions of Units IR 2 and 

IR 3 are essential to the conservation of 

the interrupted rocksnail (see Criteria 

Used to Identify Critical Habitat 

section). 

(24) Comment: The data in the 

proposed rule relative to released 

captive interrupted rocksnails are not 

consistent with ADCNR records. The 

proposed rule states that approximately 

7,400 interrupted rocksnails were 

released into the Coosa River by the 

State of Alabama 2003–2005, while 

information from ADCNR indicates that 

10,476 rocksnails were released during 

this same period. 

Our response: The numbers reported 

in the proposed rule were a 

typographical error. Records provided to 

us by TNARI and the State of Alabama 

document the release of 7,513 

interrupted rocksnails into the Coosa 

River 2003–2005. We intended to state 

that approximately 7,500 snails were 

released. TNARI records indicate 

around 10,476 snails were produced at 

its hatchery during 2003–2005. These 

production numbers may have been 

erroneously reported as released snails 

in a presentation by Dr. Paul Johnson 

(Johnson in litt. 2010). 

(25) Comment: The Service should 

develop a programmatic safe harbor 

agreement (SHA) to cover future 

releases of listed aquatic mollusks in 

Alabama. 

Our response: SHAs have been 

developed as tools to encourage private 

landowners and entities to implement 

conservation measures that maintain 

existing populations, encourage 

colonization by listed species, or 

expand existing populations. 

Programmatic SHAs have been 

developed to envelop multiple 

landowners under a single agreement, 

encouraging cooperative 

implementation and greatly reducing 

paperwork. SHAs and programmatic 

SHAs can be important conservation 

tools in recovering listed species, 

particularly in situations where the 


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cessation of voluntary conservation 

actions may result in take of listed 

species, and return their numbers to a 

pre-agreement baseline. We are willing 

to enter into SHAs, where appropriate, 

and where they would result in 

conservation benefits to the species. 

(26) Comment: Due to the lack of 

specific information on the biology of 

these species, the U.S. Army Corps of 

Engineers (Corps) could face operational 

restrictions (at Carters Reservoir) that 

have no relation to the conservation of 

the species. 

Our response: Under section 7 of the 

Act, the Corps will need to consult with 

us should their activities adversely 

affect the species or adversely modify 

their critical habitats. We have broadly 

defined activities that may destroy or 

adversely modify critical habitat below 

(see Application of the ‘‘Adverse 

Modification’’ Standard, below), and 

will work with the Corps to ensure that 

the best available information is used 

when they consult with us. Carters 

Reservoir is remote from any of the 

areas designated as critical habitat by 

this rule. The Coosawattee River below 

Carters Reservoir was designated as 

critical habitat for several mussel 

species in 2004 (see 69 FR 40084, July 

1, 2004). Our final economic analysis 

(Industrial Economics, Inc. 2010, pp. 

3–6—3–10) found that there would only 

be incremental administrative costs 

associated with this listing and critical 

habitat designation and operations at 

Carters Reservoir. 

(27) Comment: What is the present 

need for designation of critical habitat 

and its related administrative costs at a 

time of severe economic difficulty? 

Our response: We are required by the 

Act to designate critical habitat, when 

prudent and determinable, at the time of 

listing. However, our economic analysis 

identified relatively small incremental 

costs that will occur due to this critical 

habitat designation (Industrial 

Economics, Inc. 2010). Specifically, 

incremental costs are anticipated to 

result entirely from the added 

administrative requirements of forecast 

section 7 consultations, and are 

estimated to be approximately $44,000 

annually, assuming a 7 percent discount 

rate. These administrative costs are 

unlikely to have a significant effect on 

regional or national economic 

conditions. 

(28) Comment: The Service should 

avoid interference with barge 

transportation in the Alabama-CoosaTallapoosa (ACT) River system. 

Our response: The critical habitat 

designations in this rule are outside of 

or peripheral to areas used for barge 

transportation in the ACT River system. 

The economic analysis does not 

anticipate economic effects to barge 

transportation in the ACT River system 

as a result of this designation. 

(29) Comment: Speculation on future 

environmental flow releases at Carters 

Reservoir is pre-decisional, as the Corps’ 

Water Control Manual update is not 

complete. 

Our response: The economic analysis 

draws on publically available 

information, as well as insights from 

professionals involved in water 

management in the ACT basin, to arrive 

at reasonable estimates of the future 

economic impacts of species 

conservation efforts on hydropower and 

other water management activities. The 

final economic analysis includes 

additional caveats with regard to 

impacts associated with potential 

environmental flow releases related to 

Corps facilities (Industrial Economics, 

Inc. 2010, pp. 3–6—3–10). 

(30) Comment: Critical habitat 

designation could impact power 

production, increase costs, and 

potentially have significant impacts to 

municipalities and cooperatives that 

benefit from hydropower. 

Our response: The potential effects of 

this designation on power production 

were considered in the economic 

analysis. The economic analysis finds 

that water managers at four 

hydroelectric production facilities in the 

ACT Basin are likely to undertake 

conservation efforts for listed species 

that will benefit the three mollusks, at 

an estimated cost of $8.8 million 

annually. Specifically, three facilities 

(Carters, Weiss, Jordan) are expected to 

modify operations to provide additional 

flows for the benefit of downstream 

aquatic species. However, these 

modifications related to conserving the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail are expected to 

occur absent these critical habitat 

designations, because the areas affected 

have been previously designated as 

critical habitat for, and are occupied by, 

other listed mollusk species with 

similar PCEs and habitat needs. 

Incremental economic impacts resulting 

from these critical habitat designations 

are expected to arise from expected 

administrative requirements of forecast 

section 7 consultations between Federal 

regulatory agencies and the Service (see 

our response to Comment 27, above). 

(31) Comment: The listing of the 

interrupted rocksnail and its critical 

habitat could have serious negative 

impacts on landowners, businesses, and 

users of the Coosa River system because 

it will require take avoidance and 

section 7 consultations for an activity 

that may affect the population or its 

critical habitat. 

Our response: The Act does not 

require analysis of the costs of 

designating species as endangered or 

threatened. The potential economic 

impacts associated with critical habitat 

designation for the interrupted 

rocksnail, as well as costs of protective 

measures for the species already 

expected to occur without proposed 

critical habitat designation, are 

presented in the economic analysis as 

baseline costs. Specifically, incremental 

costs are anticipated to result entirely 

from the added administrative 

requirements of forecast section 7 

consultations, and are estimated to be 

approximately $44,000 annually, 

assuming a 7 percent discount rate. 

Costs associated with future 

conservation efforts that may benefit the 

three mollusks in critical habitat areas 

are estimated to be $8.97 million to 

$9.16 million annually, assuming a 7 

percent discount rate. Most (96 percent) 

of baseline costs quantified are 

conservation efforts related to potential 

lost hydropower production value at 

three facilities. 

Summary of Factors Affecting the 

Species 

Section 4 of the Act (16 U.S.C. 1533), 

and implementing regulations at 50 CFR 

part 424, set forth procedures for adding 

species to the Federal Lists of 

Endangered and Threatened Wildlife 

and Plants. Under section 4(a) of the 

Act, we may list a species on the basis 

of any of five factors, as follows: (A) The 

present or threatened destruction, 

modification, or curtailment of its 

habitat or range; (B) overutilization for 

commercial, recreational, scientific, or 

educational purposes; (C) disease or 

predation; (D) the inadequacy of 

existing regulatory mechanisms; or (E) 

other natural or manmade factors 

affecting its continued existence. 

The following analysis examines all 

five factors currently affecting or that 

are likely to affect Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail snail. The five factors listed 

under section 4(a)(1) of the Act and 

their application to the Georgia pigtoe 

mussel (Pleurobema hanleyianum), 

interrupted rocksnail (Leptoxis 

foremani), and rough hornsnail 

(Pleurocera foremani) are as follows: 

A. The Present or Threatened 

Destruction, Modification, or 

Curtailment of Its Habitat or Range 

All three species have experienced 

significant curtailment of their occupied 

habitats (see Background section). The 

Georgia pigtoe has been eliminated from 


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more than 90 percent of its historical 

range of 480 river km (298 river mi). It 

now inhabits only 43 river km (27 river 

mi). Interrupted rocksnail has been 

eliminated from 99 percent of its 

historical range of 800 river km (497 

river mi), and is now known from 12 

river km (7 river mi). The rough 

hornsnail has disappeared from more 

than 99 percent of its historical range of 

321 river km (199 river mi), and now 

occurs in less than 1 river km (0.6 river 

mi). The primary cause of range 

curtailment for all three species has 

been modification and destruction of 

river and stream habitats, primarily by 

the construction of large hydropower 

dams on the Coosa River. This habitat 

loss was compounded by fragmentation 

and isolation of the remaining freeflowing portions of the Coosa River and 

its tributaries, as well as the species’ 

increased vulnerability to local 

historical events of water quality and 

habitat degradation. 

Dams and Impoundments 

Dams eliminate or reduce river flow 

within impounded areas, trap silts and 

cause sediment deposition, alter water 

temperature and dissolved oxygen 

levels, change downstream water flow 

and quality, affect normal flood 

patterns, and block upstream and 

downstream movement of species 

(Watters 1999, pp. 261–264; McAllister 

et al. 2000, p. iii; Marcinek et al. 2005, 

pp. 20–21). Within impounded waters, 

decline of freshwater mollusks has been 

attributed to sedimentation, decreased 

dissolved oxygen, and alteration in 

resident fish populations (Neves et al. 

1997, pp. 63–64; Watters 1999, pp. 261– 

264; Marcinek et al. 2005, pp. 9–10). 

Below dams, mollusk declines are 

associated with changes and fluctuation 

in flow regime, scouring and erosion, 

reduced dissolved oxygen levels and 

water temperatures, and changes in 

resident fish assemblages (Williams et 

al. 1992b, p. 7; Neves et al. 1997, pp. 

63–64; Watters 1999, pp. 261–264; 

Marcinek et al. 2005, pp. 20–21). The 

decline and extinction of freshwater 

snails and mussels in the Mobile River 

Basin has been directly attributed to 

construction of numerous large 

impoundments in the major river 

systems (Williams et al. 1992b, pp. 1– 

8; Bogan et al. 1995, pp. 250–251; 

Lydeard and Mayden 1995, pp. 803– 

804; Neves et al. 1997, pp. 62, 64; 

Marcinek et al. 2005, p. 9). 

The Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail are all 

endemic to the Coosa River system. The 

Coosa River was impounded by six 

major dams constructed between 1928 

and 1966. Today, more than 60 percent 

of the Coosa River and its 19 largest 

tributaries are inundated or affected by 

flow regulation (Marcinek et al. 2005, 

pp. 12–16). 

Dam construction on the Coosa River 

had a secondary effect of fragmenting 

the ranges of aquatic mollusk species, 

such as the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail, leaving 

relict habitats and populations isolated 

by the structures as well as by extensive 

areas of uninhabitable, impounded 

waters. Isolated populations were left 

more vulnerable to, and affected by, 

natural events (such as droughts), runoff 

from common land-use practices (such 

as agriculture, mining, urbanization), 

discharges (such as municipal and 

industrial wastes), and accidents (such 

as chemical spills) that reduced 

population levels or eliminated habitat 

(Neves et al. 1997, pp. 64–71; U.S. Fish 

and Wildlife Service 2000, pp. 14–15). 

As a result, many relict populations 

became locally extirpated, and many 

mollusk species were driven to 

extinction (Bogan et al. 1995, pp. 250– 

251; Lydeard and Mayden 1995, pp. 

803–804; Neves et al. 1997, pp. 54, 62; 

U.S. Fish and Wildlife Service 2000, pp. 

6–9). If conditions subsequently 

improved, the surviving mollusk species 

were unable to naturally recolonize 

suitable areas, due to impediments 

created by the dams and impounded 

waters. 

The only known natural population of 

the interrupted rocksnail occurs in the 

free-flowing Oostanaula River (Williams 

and Hughes 1998, p. 9; Johnson and 

Evans 2001, p. 25). The Oostanaula 

River is formed by the confluence of the 

Conasauga and Coosawatee Rivers. The 

Upper Coosawatee is impounded by 

Carters Dam, a hydropower dam which 

discharges into Carters Re-regulation 

Dam and from there into the Coosawatee 

River. Hydropower discharges from 

Carters Dam are believed to be 

implicated in the disappearance of the 

interrupted rocksnail from the 

Coosawattee River (Johnson and Evans 

2001, p. 26). The effects of power 

generation discharges from Carters Dam, 

including cold water temperatures are 

evident downstream (Williams and 

Hughes 1998, p. 11), even to the shoals 

on the Oostanaula River where the 

interrupted rocksnail is found (Johnson 

and Evans 2001, p. 26; Marcinek et al. 

2005, p. 15). A Federal Energy 

Regulatory Commission (FERC) license 

was issued to construct a hydroelectric 

facility on the Carters Re-regulation 

Dam (FERC 2001, pp. 1–2). A notice of 

probable termination of license has been 

issued due to failure to commence 

construction in a timely manner (FERC 

2005a, pp. 1–2). The applicant appealed 

the termination order (FERC 2005b, p. 

1), but was denied (FERC 2006a, pp. 1– 

3). However, the applicant has since 

applied for a preliminary permit to 

proceed with the hydroelectric facility 

and issued a Notice of Intent and related 

documents to file for a license 

application at Carters Re-Regulation 

Dam (Fall Line Hydro Company, Inc. 

2009). 

Rough hornsnails currently survive in 

Lower Yellowleaf Creek, at the 

transitional area between the flowing 

stream and the embayment created by 

Lay Dam, and in a small area of the 

Coosa River below the shoals along the 

Fall Line near Wetumpka, Alabama. 

Known from the main channel of the 

Coosa River and the mouths of some of 

the larger tributaries, all historical 

habitats, including the two where the 

rough hornsnail currently survives, are 

affected to some degree by impounded 

waters and hydropower releases. 

The Georgia pigtoe historically 

occurred in the Coosa River and many 

of its major tributaries. As noted above, 

the Coosa is impounded throughout 

most of its length by major hydropower 

dams. In addition, all historically 

occupied tributaries are isolated from 

each other by one or more of these dams 

and extensive reaches of impounded 

waters. The species is currently known 

to survive only in the Upper Conasauga 

River, far above the influence of the 

Coosa River impoundments. 

Water and Habitat Quality 

The disappearance of shoal 

populations of rough hornsnail, 

interrupted rocksnail, and Georgia 

pigtoe from unimpounded relict habitats 

in the Coosa River drainage is likely due 

to historical pollution problems. 

Pleurocerid snails and freshwater 

mussels are highly sensitive to water 

and habitat quality (Havlik and Marking 

1987, pp. 1–15; Neves et al. 1997, pp. 

64–69). Historical causes of water and 

habitat degradation in the Coosa River 

and its tributaries included drainage 

from gold mining activities, industrial 

and municipal pollution events, and 

construction and agricultural runoff (for 

example, Hurd 1974, pp. 38–40; 

Lydeard and Mayden 1995, pp. 803– 

804; Freeman et al. 2005, pp. 560–562). 

Prior to the passage of the Federal 

Clean Water Act (33 U.S.C. 1251 et seq., 

1972) and the adoption of State water 

quality regulations and criteria, water 

pollution was a significant factor in the 

disappearance of mollusks from 

unimpounded river and stream 

channels in the Mobile River Basin 

(Baldwin 1973, p. 23; Hurd 1974, pp. 

38–40, 144–151). Hurd (1974, pp. 147– 

149), for example, noted the extirpation 


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of freshwater mussel communities from 

the Conasauga River below Dalton, 

Georgia, apparently as a result of textile 

and carpet mill waste discharges. He 

also attributed the disappearance of the 

mussel fauna from the Etowah River and 

other tributaries of the Coosa River to 

organic pollution and siltation. Baldwin 

(1973, p. 23) documented the loss of 

mussel diversity in the Cahaba River 

and identified the primary causes as 

pollution from coalfields and industrial 

and urban wastes. 

Although Federal and State water 

quality laws and regulations have 

generally reduced the impacts of point 

source discharges, nonpoint source 

pollution continues to affect and 

possibly threaten the remaining 

populations of each of these mollusk 

species. Nonpoint source pollution has 

been identified as a concern in the 

Yellowleaf Creek and Lower Coosa 

River watersheds (Alabama Clean Water 

Partnership (ACWP) 2005 Chapter 12). 

These drainages encompass historical 

habitat for the interrupted rocksnail and 

Georgia pigtoe, currently occupied 

habitat for the rough hornsnail, and a 

recent reintroduction of the interrupted 

rocksnail. Both Yellowleaf Creek and 

the eastern watershed of the Lower 

Coosa River have been designated as 

High Priority Watersheds by the ACWP 

(2005 Chap. 12), due to the high 

potential of nonpoint source pollution 

associated with expanding human 

population growth rates and 

urbanization. The headwaters of 

Yellowleaf Creek are about 5 km (3 mi) 

southeast of the greater metropolitan 

area surrounding Birmingham, and the 

watershed is highly dissected by county 

roads. The Lower Coosa River is about 

16 km (10 mi) north of the Montgomery 

greater metropolitan area and is 

accessible by a four lane highway. Both 

general areas are experiencing growth 

due to their proximity to major 

metropolitan areas. 

Nonpoint source pollution and habitat 

deterioration are also problems in the 

Upper Coosa River Basin, including the 

Conasauga and Oostanaula rivers 

(Georgia Department of Natural 

Resources (GDNR) 1998, pp. 4.27–4.42). 

In the reaches of the Conasauga River 

where the Georgia pigtoe continues to 

survive, overall molluscan abundance 

and diversity have experienced a 

general decline over the past 2 decades 

that has been primarily attributed to 

water or sediment toxicity and channel 

instability (Johnson and Evans 2000, pp. 

171–173; Sharpe and Nichols 2005, pp. 

81–88). Sedimentation has been 

identified as a potential limiting factor 

for the interrupted rocksnails in the 

Oostanaula River (Johnson and Evans 

2001, p. 26). Following its rediscovery, 

the interrupted rocksnail population 

size in the Oostanaula River has 

declined from a high of 10 to 45 snails 

per square meter (10.7 sq ft) in 1999 

(Johnson and Evans 2001, p. 22) to only 

20 snails found during 6 search-hours in 

2004 (Johnson in litt. 2003, 2004). The 

cause of decline is suspected to be some 

form of water contamination (Johnson in 

litt. 2003, 2004; Hartfield in litt. 2006). 

Nonpoint source pollution from land 

surface runoff originates from virtually 

all land use activities and includes 

sediments; fertilizer, herbicide, and 

pesticide residues; animal or human 

wastes; septic tank leakage and gray 

water discharge; and oils and greases 

(GDNR 1998, pp. 4.27–4.42; ACWP 

2005, Chap. 9). Nonpoint source 

pollution can cause excess 

sedimentation, nutrification, decreased 

dissolved oxygen concentration, 

increased acidity and conductivity, and 

other changes in water chemistry that 

can seriously impact aquatic mollusks. 

Land use types around the Georgia 

pigtoe, interrupted rocksnail, and rough 

hornsnail populations include pastures, 

row crops, timber, and urban and rural 

communities. 

Excessive sediments are believed to 

impact riverine mollusks requiring 

clean, stable streams (Ellis 1936, pp. 39– 

40; Brim Box and Mossa 1999, p. 99). 

Impacts resulting from sediments have 

been noted for many components of 

aquatic communities. For example, 

sediments have been shown to abrade or 

suffocate periphyton (organisms 

attached to underwater surfaces, upon 

which snails may feed); affect 

respiration, growth, reproductive 

success, and behavior of aquatic insects 

and mussels; and affect fish growth, 

survival, and reproduction (Waters 

1995, pp. 173–175). Potential sediment 

sources within a watershed include 

virtually all activities that disturb the 

land surface, and all localities currently 

occupied by these mollusks are affected 

to varying degrees by sedimentation. 

Land surface runoff also contributes 

nutrients to rivers and streams. 

Excessive nutrient input (for example, 

nitrogen and phosphorus from 

fertilizers, sewage, and animal manure) 

can result in effects that are detrimental 

to aquatic species. High levels of 

nutrients in surface runoff can promote 

excessive filamentous algal growth. 

Dense algal growth covers gravel, 

cobble, or bedrock substrates and 

interstices (spaces between bottom 

particles), and can seriously reduce 

dissolved oxygen in waters during dark 

hours due to algal respiration (Shepard 

et al. 1994, pp. 61–64), which affects 

feeding, reproduction, and respiration 

in adult and juvenile mussels and 

snails, and limits access to substrate 

interstices important to juvenile and 

adult mussels. Algal mats also provide 

cover for invertebrate predators of 

juvenile mollusks (such as flatworms, 

hydra, and chironomids) and increase 

their vulnerability to such predators. 

Filamentous algae may also displace 

certain species of fish, or otherwise 

affect fish–mussel interactions essential 

to recruitment (for example, Hartfield 

and Hartfield 1996, p. 373). In 

hatcheries, filamentous algal growth 

reduces juvenile mussel survival by 

reducing flow, increasing 

sedimentation, and causing competition 

with and reduction of the unicellular 

algal community on which the mussels 

feed (Neves Pers. comm. 2002). Nutrient 

and sediment pollution may have 

synergistic effects (when the toxic effect 

of two or more pollutants operating 

together is greater than the sum of the 

effects of the pollutants operating 

individually) on freshwater mollusks, as 

has been suggested for aquatic insects 

(Waters 1995, p. 67). 

Land surface runoff contributes the 

majority of human-induced sediments 

and nutrients to water bodies 

throughout the United States. The 

human population is expanding within 

the areas currently occupied by the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail, increasing the 

sediment and nutrient input to their 

riverine habitats, and leaving these 

mollusks vulnerable to progressive 

water and habitat degradation from land 

surface runoff. 

Accidental spills that may affect water 

or habitat quality also threaten surviving 

populations of each species. For 

example, on September 12, 2006, a train 

derailment spilled four tank cars of 

soybeans into a tributary of Yellowleaf 

Creek (Birmingham News in litt. 2006). 

A large rain event flushed the 

decomposing soybeans into Yellowleaf 

Creek, resulting in a serious decline in 

dissolved oxygen in the stream, killing 

fishes, mussels (including two 

endangered species, southern pigtoe 

(Fusconaia cerina) and triangular 

kidneyshell (Ptychobranchus greenii)), 

and snails (including the endangered 

cylindrical lioplax (Lioplax 

cyclostomaformis)) (Johnson 2006). 

Fortunately, the location of the largest 

surviving population of rough hornsnail 

is in the lowest reaches of Yellowleaf 

Creek, remote from the spill, and no 

mortality was observed in this 

population as a result of the spill 

(Johnson 2006). 

In summary, the historical loss of 

habitat and range is currently, and 

projected to continue to be, a significant 


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threat to the rough hornsnail, 

interrupted rocksnail, and Georgia 

pigtoe. Curtailment of habitat and range 

also amplifies threats from nonpoint 

source water and habitat quality 

degradation, accidental spills, or 

violation of permitted discharges. Due 

to the extremely limited extent of 

habitat currently occupied by each 

species, and the severity and magnitude 

of this threat, we have determined that 

the present or threatened destruction, 

modification, or curtailment of habitat 

and range represents an ongoing and 

significant threat to the rough hornsnail, 

interrupted rocksnail, and Georgia 

pigtoe. 

B. Overutilization for Commercial, 

Recreational, Scientific, or Educational 

Purposes 

The Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail are not 

commercially utilized. Each species has 

been taken for scientific and private 

collections in the past, yet collecting is 

not considered a factor in the decline of 

these species. While collection is not 

considered a current threat, the 

desirability of these species in scientific 

and commercial collections may 

increase as their existence and rarity 

becomes known, and their localized 

distributions and small population sizes 

leaves them vulnerable to overzealous 

recreational or scientific collecting. 

C. Disease or Predation 

Diseases of freshwater mollusks are 

poorly known and are not currently 

considered to be a threat to the Georgia 

pigtoe, interrupted rocksnail, or rough 

hornsnail, nor a factor in their decline. 

Aquatic snails and mussels are 

consumed by various vertebrate 

predators, including fishes, mammals, 

and possibly birds. Although predation 

by naturally occurring predators is a 

normal aspect of the population 

dynamics of a species and is not known 

to be a threat to any of these species, 

changes in water flows, depths, 

temperatures, and other environmental 

factors within some portions of their 

ranges may have led to increased 

numbers of native mollusk-eating fish, 

such as freshwater drum (Johnson in 

litt. 2005b). In addition, the potential 

now exists for the black carp 

(Mylopharyngodon piceus), a molluskeating Asian fish recently introduced 

into the waters of the United States 

(U.S. Fish and Wildlife Service 2002, p. 

49280), to eventually enter and disperse 

through the Mobile River Basin via the 

Tennessee-Tombigbee Waterway, or by 

their accidental release from catfish 

farms or other aquaculture facilities. 

In summary, disease in freshwater 

mollusks is poorly known and is not 

currently considered a threat to the 

Georgia pigtoe, interrupted rocksnail, or 

rough hornsnail. Although there is no 

direct evidence at this time that 

predation is detrimentally affecting the 

Georgia pigtoe, interrupted rocksnail, or 

rough hornsnail, their small populations 

and limited ranges leaves them 

vulnerable to threats of predation from 

natural or introduced predators. 

Therefore, we have concluded that 

predation currently represents a threat 

of low magnitude, but it could 

potentially become a significant future 

threat to the Georgia pigtoe, interrupted 

rocksnail, or rough hornsnail due to 

their small population sizes. 

D. The Inadequacy of Existing 

Regulatory Mechanisms 

The Alabama Department of 

Conservation and Natural Resources 

currently recognizes the rough hornsnail 

as a ‘‘Priority 1’’ species (Highest 

Conservation Concern) (Mirarchi et al. 

2004, p. 117; ADCNR 2005, p. 302). The 

interrupted rocksnail is considered 

‘‘Extirpated (in Alabama)—Conservation 

Action Underway’’ (Mirarchi et al. 2004, 

p. 114), and the Georgia pigtoe is listed 

as ‘‘extinct’’ (Mirarchi et al. 2004, p. 13). 

While these classifications identify the 

status of imperiled species in the State 

of Alabama, they convey no legal 

protection. Interrupted rocksnail and 

Georgia pigtoe currently lack any 

official status recognition by the State of 

Georgia, but they have been nominated 

for inclusion on the State Protected 

Species List. The Georgia pigtoe is 

identified as a species of the Greatest 

Conservation Need by the State of 

Tennessee. NatureServe (2010) 

identifies the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail as G1 critically imperiled 

species; however, no State or Federal 

protection is conveyed by these 

classifications. Without State or Federal 

protection, these three species are not 

currently given any specific special 

consideration under environmental laws 

when project impacts are reviewed, 

other than those provided for water 

quality. 

The mollusk fauna (including the 

Georgia pigtoe) of the Conasauga River 

and the interrupted rocksnail in the 

Oostanaula River have experienced 

significant declines in recent years, 

apparently due to water quality or 

sediment toxicity (Evans 2001, p. 3; 

Johnson in litt. 2004; Sharpe and 

Nichols 2005, pp. 1–4; Konwick et al. 

2008, pp. 2016–2017). There is no 

specific scientific information on the 

sensitivity of the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail or their host fish species to 

common industrial and municipal 

pollutants, and little information on 

other freshwater mollusks. Current State 

and Federal regulations regarding 

pollutants are assumed to be protective 

of freshwater mollusks; however, these 

species may be more susceptible to 

some pollutants than test organisms 

commonly used in bioassays. For 

example, several recent studies suggest 

that U.S. Environmental Protection 

Agency’s (EPA) criteria for ammonia 

may not be protective of freshwater 

mussels (Augspurger et al. 2003, p. 

2571; Augspurger et al. 2007, p. 2026; 

Newton et al. 2003, pp. 2559–2560; 

Newton and Bartsch 2007, p. 2057; 

Ward et al. 2007, p. 2075). 

In a review of the effects of 

eutrophication on mussels, Patzner and 

Muller (2001, p. 329) noted that 

stenoecious (narrowly tolerant) species 

disappear as waters become more 

eutrophic. They also refer to studies that 

associate increased levels of nitrate with 

the decline and absence of juvenile 

mussels (Patzner and Muller 2001, pp. 

330–333). Other studies also suggest 

that early life stages of mussels are more 

sensitive to metals and such inorganic 

chemicals as chlorine and ammonia 

than are common bioassay test 

organisms (Keller and Zam 1991, pp. 

543–545; Goudreau et al. 1993, p. 221; 

Naimo 1995, pp. 354–355). Therefore, it 

appears that inadequate research and 

data prevent existing regulations, such 

as the Clean Water Act (administered by 

the EPA and the Corps), from being fully 

utilized or effective in the management 

and protection of these species. 

Rough hornsnails currently survive at 

localized sites in Yellowleaf Creek and 

in the Lower Coosa River below 

Wetumpka Shoals in Alabama. In 

addition, the interrupted rocksnail was 

recently reintroduced into Wetumpka 

Shoals. The Alabama Department of 

Environmental Management (ADEM) 

has designated the water use 

classification for some portions of 

Yellowleaf Creek as ‘‘Swimming’’ (S) 

and others as ‘‘Fish and Wildlife’’ (F&W). 

The F&W designation establishes 

minimum water quality standards that 

are believed to protect existing species 

and water uses (for example, fishing, 

recreation, irrigation) within the 

designated area, while the S 

classification establishes higher water 

quality standards that are protective of 

human contact with the water. The 

Lower Coosa River below Wetumpka is 

currently designated as F&W by ADEM, 

and adjacent tributaries are classified as 

S. Both water bodies are currently 

believed to support their designated 


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uses. However, Yellowleaf Creek and 

the eastern watershed of the Lower 

Coosa have been designated as High 

Priority Watersheds by the ACWP (2005, 

Chap. 12), due to a lack of monitoring 

data and the high potential of nonpoint 

source pollution in these drainages 

associated with expanding human 

population growth rates and 

urbanization. 

The reach of the Conasauga River at 

and below the Tennessee–Georgia State 

Line supports the only known surviving 

population of the Georgia pigtoe. This 

river reach is identified on Georgia’s 

303(d) list of impaired waters as 

partially supporting its designated use 

of Fishing–Drinking Water (GDNR 2006, 

p. 35). The Georgia 303(d) list identifies 

high levels of fecal coliform bacteria and 

polychlorinated biphenyls (PCBs) as the 

reasons for this river reach’s inclusion 

on the list; nonpoint pollution is 

identified as the source of pollutants 

(GDNR 2006, p. 35). Recent studies also 

implicate sediment and water toxicity in 

the decline of mollusks in the 

Conasauga River (Sharpe and Nichols 

2005, pp. 81–88; Konwick et al. 2008, 

pp. 2016–2017). 

States maintain water-use 

classifications through issuance of 

National Pollutant Discharge 

Elimination System (NPDES) permits to 

industries, municipalities, and others 

that set maximum limits on certain 

pollutants or pollutant parameters. For 

water bodies on the 303(d) list, States 

are required under the Clean Water Act 

to establish a total maximum daily load 

(TMDL) for the pollutants of concern 

that will bring water quality into the 

applicable standard. The Georgia 

Department of Natural Resources has 

identified TMDLs for the Oostanaula 

River to address existing problems of 

PCBs and fecal coliform loads from 

nonpoint source and urban runoff 

sources. 

In summary, recent declines in 

mollusk communities within the ranges 

of each of these species has been 

attributed to poor water or sediment 

quality. Although regulatory 

mechanisms are in place to protect 

aquatic species, a lack of specific 

information on the sensitivity of the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail and their host fish 

to common industrial and municipal 

pollutants limits their application. 

Water and sediment quality is believed 

to currently affect (and is expected to 

continue to affect) the Georgia pigtoe 

and interrupted rocksnail and has been 

identified as a concern for the rough 

hornsnail in Yellowleaf Creek. 

Therefore, we determine that inadequate 

existing regulatory mechanisms are an 

imminent threat of high magnitude to 

the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail. 

E. Other Natural or Manmade Factors 

Affecting Its Continued Existence 

As noted under Factor A, above, the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail have been 

eliminated from 90 percent or more of 

their historical ranges. Surviving 

populations of each species are small, 

extremely localized, isolated, and 

vulnerable to habitat modification, toxic 

spills, and progressive degradation from 

land surface runoff (nonpoint source 

runoff) (see Factor A: Dams and 

Impoundments, Water and Habitat 

Quality; and Factor D: The inadequacy 

of existing regulatory mechanisms). 

These conditions also leave each species 

vulnerable to catastrophic changes to 

their habitats that may result from 

natural events such as flood scour or 

drought. 

There is a growing concern that 

climate change may lead to increased 

frequency of severe storms and droughts 

(for example, Golladay et al. 2004, p. 

504; McLaughlin et al. 2002, p. 6074; 

Cook et al. 2004, p. 1015). During 2007 

and 2008, a severe drought affected the 

Coosa River watershed in Alabama and 

Georgia. Streamflow for the Conasauga 

River at Tilton, Georgia, during 

September 2007, was the lowest 

recorded for any month in 69 years (U.S. 

Geological Survey 2007, pp. 1–2). 

Although the effects of the drought on 

the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail have not 

been quantified, mollusk declines as a 

direct result of drought have been 

documented (for example, Golladay et 

al. 2004, p. 494; Haag and Warren 2008, 

p. 1165). Reduction in local water 

supplies due to drought is also 

compounded by increased human 

demand and competition for surface and 

ground water resources for power 

production, irrigation, and consumption 

(Golladay et al. 2004, p. 504). 

Freshwater mussels and snails are 

capable of moving only short distances. 

As noted previously (see discussion 

under Factor A: Dams and 

Impoundments), there are numerous 

obstacles in the Coosa River drainage 

preventing long distance movement of 

snails, mussels, or the fish hosts of 

mussels between relict patches of 

historically occupied and potentially 

suitable riverine habitats. Therefore, 

even if habitat conditions improve for 

the survival of the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail in historically occupied 

stream and river habitats, they will be 

unable to recolonize those areas without 

human assistance. Low numbers of 

individuals within these isolated 

populations also increase the risks and 

consequences of inbreeding and 

reduced genetic diversity (Lynch 1996, 

pp. 493–494). 

The Georgia pigtoe may be adversely 

affected by the loss or reduction in 

numbers of the fish host(s) essential to 

its parasitic glochidial stage. The 

specific fish host(s) for the glochidia of 

the Georgia pigtoe is unknown; 

therefore, specific impacts on this 

aspect of the mussels’ life cycle cannot 

be evaluated. However, other species of 

mussels in the genus Pleurobema are 

known to parasitize various species of 

chubs, minnows, stonerollers, and other 

stream fish species. 

In summary, a variety of natural or 

manmade factors, such as droughts, 

storms, and toxic spills, threaten 

surviving populations of the Georgia 

pigtoe, interrupted rocksnail, and rough 

hornsnail due to the highly restricted 

and fragmented nature of their habitats 

and their small population sizes. Other 

factors, such as inbreeding, reduced 

genetic diversity, and loss or reduction 

of fish hosts for the Georgia pigtoe, may 

threaten each of the three species; 

however, the severity and magnitude of 

these threats are not currently known. 

However, we have determined that 

natural and manmade factors, such as 

accidental spills, floods, and droughts, 

currently pose an imminent and high 

degree of threat to the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail, and the levels of these threats 

are projected to continue or increase in 

the future. 

Conclusion and Determination 

We carefully assessed the best 

scientific and commercial information 

available regarding the past, present, 

and future threats to the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail. Section 3(6) of the Act 

defines an endangered species as ‘‘any 

species which is in danger of extinction 

throughout all or a significant portion of 

its range.’’ We find that each of these 

three species is presently in danger of 

extinction throughout its entire range, 

based on the immediacy and magnitude 

of the threats described above. Based on 

our analysis, we have no reason to 

believe that population trends for any of 

the three species addressed in this final 

rule will improve, nor will the effects of 

current threats acting on the species be 

ameliorated in the foreseeable future. 

Therefore, on the basis of the best 

available scientific and commercial 

information, we are listing the Georgia 

pigtoe, interrupted rocksnail, and rough 

hornsnail as endangered under the Act. 


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Without the protection of the Act, 

these species are in danger of extinction 

throughout all of their ranges. This 

could occur within a few years, given 

recurring drought conditions, accidents, 

or other existing threats. Furthermore, 

because of their curtailed ranges, and 

immediate and ongoing significant 

threats to each species throughout their 

entire respective ranges, as described 

above in the five-factor analysis, we find 

that it is unnecessary to analyze 

whether there are any significant 

portions of ranges for each species that 

may warrant a different determination 

of status. 

Summary of Critical Habitat Changes 

From Proposed Rule 

We have considered all comments 

and information received during the 

open comment period for the proposed 

rule to designate critical habitat for the 

Georgia pigtoe mussel, interrupted 

rocksnail, and rough hornsnail. We have 

included mud as a substrate utilized by 

the rough hornsnail based upon 

information provided by a peer 

reviewer, and added this descriptor into 

PCE 4 for the rough hornsnail (see Peer 

Review, above, and rough hornsnail PCE 

4, below). We have also modified PCE 

3 for all three species to reflect 

information under Factors A and D, 

above, that some parameters identified 

under current water quality life criteria 

established under the Clean Water Act 

(33 U.S.C. 1251–1387) are not adequate 

to sustain normal behavior, growth, and 

viability of all life stages of mollusks. 

We have also defined the upstream and 

downstream limits of the critical habitat 

units by Universal Transverse Mercator 

(UTM) zone 16, coordinates in the 

Regulation Promulgation, below. No 

other changes have been made to the 

proposed designation, including the 

number, extent, and location of the 

individual units designated as critical 

habitat. 

Critical Habitat 

Critical habitat is defined in section 3 

of the Act as: 

(1) 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 

(a) Essential to the conservation of the 

species, and 

(b) Which may require special 

management considerations or 

protection; and 

(2) Specific areas outside the 

geographical area occupied by 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 

that are necessary to bring any 

endangered species or threatened 

species to the point at which measures 

provided under the Act are no longer 

necessary. 

Critical habitat receives protection 

under section 7 of the Act through the 

prohibition against Federal agencies 

carrying out, funding, or authorizing the 

destruction or adverse modification of 

critical habitat. Section 7(a)(2) of the Act 

requires consultation on Federal actions 

that may affect critical habitat. The 

designation of critical habitat does not 

affect land ownership or establish a 

refuge, wilderness, reserve, preserve, or 

other conservation area. Such 

designation does not allow the 

government or public to access private 

lands. Such designation does not 

require implementation of restoration, 

recovery, or enhancement measures by 

private landowners. Where a landowner 

requests Federal agency funding or 

authorization for an action that may 

affect a listed species or critical habitat, 

the consultation requirements of Section 

7(a)(2) may apply. However, even in the 

event of a destruction or adverse 

modification finding, the Federal action 

agency’s and the applicant’s obligation 

is not to restore or recover the species, 

but to implement reasonable and 

prudent alternatives to avoid 

destruction or adverse modification of 

critical habitat. 

To be included in a critical habitat 

designation, the habitat within the 

geographic area occupied by the species 

must first have the physical and 

biological features that are essential to 

the conservation of the species. The 

Service must identify, to the extent 

known using the best scientific data 

available, habitat areas that provide 

essential life cycle needs of the species 

(i.e., areas on which are found the 

Primary Constituent Elements (PCEs), as 

defined at 50 CFR 424.12(b)). Second, to 

be included in the designation, the 

features at issue must also be ones that 

may require special management 

considerations or protection. Under the 

Act, we can designate unoccupied areas 

as critical habitat only when we 

determine that the best available 

scientific data demonstrate that the 

designation of that area is essential to 

the conservation needs of the species. 

Section 4 of the Act requires that we 

designate critical habitat on the basis of 

the best scientific and commercial data 

available. Furthermore, our ‘‘Policy on 

Information Standards Under the 

Endangered Species Act,’’ published in 

the Federal Register on July 1, 1994 (59 

FR 34271), the Information Quality Act 

(section 515 of the Treasury and General 

Government Appropriations Act for 

Fiscal Year 2001 (Pub. L. 106–554; H.R. 

5658)), and our associated Information 

Quality Guidelines provide criteria, 

establish procedures, and provide 

guidance to ensure that our decisions 

represent the best scientific data 

available. 

When determining which areas we 

should propose as critical habitat, our 

primary source of information is 

generally the information developed 

during the listing process for the 

species. Additional information sources 

may include 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. 

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 we 

may eventually determine, based on 

scientific data not now available to the 

Service, are necessary for the recovery 

of the species. For these reasons, a 

critical habitat designation should not 

be interpreted as meaning that habitat 

outside the designated area is 

unimportant or may not be required for 

recovery of the species in question. 

Areas that support populations, but 

are outside the critical habitat 

designation, will continue to be subject 

to conservation actions we implement 

under section 7(a)(1) of the Act. They 

are also subject to the regulatory 

protections afforded by the section 

7(a)(2) jeopardy standard, as determined 

on the basis of the best available 

scientific information at the time of the 

agency 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 (HCPs), or other species 

conservation planning efforts if new 

information available to these planning 

efforts calls for a different outcome. 

Methods 

As required by section 4(b)(2) of the 

Act, we use the best scientific data 

available in determining occupied areas 


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that contain the features that are 

essential to the conservation of the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail, and unoccupied 

areas that are essential to the 

conservation of the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail. 

We have reviewed the available 

information pertaining to historical and 

current distributions, life histories, and 

habitat requirements of these species. 

Our sources included: peer reviewed 

scientific publications; unpublished 

survey reports; unpublished field 

observations by the Service, State, and 

other experienced biologists; and notes 

and communications from qualified 

biologists or experts. 

Primary Constituent Elements (PCEs) 

In accordance with sections 3(5)(A)(i) 

of the Act and regulations at 50 CFR 

424.12, in determining which areas 

within the geographical area occupied at 

the time of listing are critical habitat, we 

identify the specific PCEs required for 

the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail based on 

their biological needs. We consider the 

physical and biological features that are 

essential to the conservation of each 

species to be the PCEs laid out in the 

appropriate quantity and spatial 

arrangement for the conservation of the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail. These include, but 

are not limited to: 

(1) Space for individual and 

population growth and for normal 

behavior; 

(2) Food, water, air, light, minerals, or 

other nutritional or physiological 

requirements; 

(3) Cover or shelter; 

(4) Sites for breeding, reproduction, 

and rearing (or development) of 

offspring; and 

(5) Habitats that are protected from 

disturbance or are representative of the 

historical, geographical, and ecological 

distribution of a species. 

The PCEs required for the Georgia 

pigtoe, interrupted rocksnail, and rough 

hornsnail are derived from biological 

needs of the species as described in the 

Background section of this rule. 

Unfortunately, little is known of the 

specific habitat requirements of any of 

these mollusk species other than all 

three require flowing water, stable 

stream or river channels, and adequate 

water quality. Georgia pigtoe mussel 

larvae also require a currently unknown 

fish host for development to juvenile 

mussels. To identify the physical and 

biological needs of the species, we have 

relied on current conditions at locations 

where each of the species survive, the 

limited information available on these 

three species and their close relatives, 

and factors associated with the decline 

and extirpation of these and other 

aquatic mollusks from extensive 

portions of the Mobile River Basin. 

Space for Individual and Population 

Growth and for Normal Behavior 

The Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail were all 

historically associated with stream and 

river shoals of the Coosa River drainage 

(Goodrich 1922, p. 5; Johnson and Evans 

2001, p. 21; Williams et al. 2008). The 

decline of the aquatic mollusk fauna of 

the Mobile River Basin is directly 

associated with the loss of shoal 

habitats, primarily due to inundation by 

impounded waters (Bogan et al. 1995, 

pp. 250–251; Lydeard and Mayden 

1995, pp. 803–804; Neves et al. 1997, 

pp. 63–64; Marcinek et al. 2005, pp. 7– 

10, 20–21). Shoals are defined as 

discrete areas that are of lower depth, 

greater slope, higher velocity flows, and 

coarser bed materials relative to other 

channel segments. Shoals include areas 

that are also referred to as riffles, gravel 

bars, and reefs. Shoals generally have 

substrates composed of bedrock, cobble, 

boulder, and gravel interspersed with 

sands, and sufficient current velocities 

to remove finer sediments and maintain 

interstitial habitats (Marcinek et al. 

2005, p. 4). The interrupted rocksnail 

and rough hornsnail are found clinging 

to gravel, cobble, and boulders in 

moderate to strong currents in shoals, 

while Georgia pigtoe mussels are found 

imbedded in sand–gravel substrates 

within shoals. Rough hornsnails are also 

found in pools with mud or silt bottoms 

below shoals. Shoals and associated 

pools not only provide space for these 

three mollusks, but also provide cover 

and shelter and sites for breeding, 

reproduction, and growth of offspring. 

Shoal–pool habitats are formed and 

maintained by water quantity, channel 

slope, and sediment input to the system. 

Changes in one or more of these 

parameters can result in channel 

degradation or channel aggradation, 

with serious effects to mollusks. 

Therefore, we believe that stream 

channel stability is essential to the 

conservation of the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail. 

Food 

The interrupted rocksnail and rough 

hornsnail generally feed by ingesting 

periphyton and biofilm detritus scraped 

off the substrate by the snail’s radula 

(Morales and Ward 2000, p. 1). Unionid 

mussels, such as the Georgia pigtoe, 

filter algae, detritus, and bacteria from 

the water column (Williams et al. 2008, 

p. 67). Food availability and quality for 

the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail in shoal 

habitats are affected by habitat stability, 

water flow, and water quality. 

Water 

The Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail are 

riverine-adapted species that depend 

upon adequate water flow (Williams et 

al. 2008, p. 534; Goodrich 1922, p. 5) 

and are not found in ponds or lakes. 

Continuously flowing water is a habitat 

feature associated with all surviving 

populations of the three species. 

Flowing water maintains the stream 

bottom and shoal habitats where these 

species are found, transports food items 

to the sedentary juvenile and adult life 

stages of the Georgia pigtoe, supports 

the periphyton and biofilm ingested by 

the interrupted rocksnail and rough 

hornsnail, removes wastes, and provides 

oxygen for respiration for each of the 

three species. 

The ranges of standard physical and 

chemical water quality parameters (such 

as temperature, dissolved oxygen, pH, 

conductivity) that define suitable 

habitat conditions for the Georgia 

pigtoe, interrupted rocksnail, and rough 

hornsnail have not been investigated. 

However, as relatively sedentary 

animals, aquatic snails and mussels 

must tolerate the full range of such 

parameters that occur naturally within 

the streams where they persist. Both the 

amount (flow) and the physical and 

chemical conditions (water quality) 

where each of the three species 

currently exist vary widely according to 

season, precipitation events, and 

seasonal human activities within the 

watershed. Conditions across their 

historical ranges vary even more due to 

watershed size, geology, geography, and 

differences in human population 

densities and land uses. In general, each 

of the species survives in areas where 

the magnitude, frequency, duration, and 

seasonality of water flow are adequate to 

maintain stable shoal habitats (for 

example, sufficient flow to remove fine 

particles and sediments without causing 

degradation), and where water quality is 

adequate for year-round survival (for 

example, moderate to high levels of 

dissolved oxygen, low to moderate 

input of nutrients, and relatively 

unpolluted water and sediments). 

Therefore, adequate water flow and 

water quality (as defined below) are 

essential to the conservation of the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail. We currently 

believe that most numeric standards for 

pollutants and water quality parameters 


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(for example, dissolved oxygen, pH, 

heavy metals) that have been adopted by 

the States under the Clean Water Act 

represent levels that are essential to the 

conservation of each of these three 

mollusks. However, some States’ 

standards may not adequately protect 

mollusks, or are not being appropriately 

measured, monitored, or achieved in 

some reaches (see Factor A: The present 

or threatened destruction, modification, 

or curtailment of its habitat or range, 

Water and Habitat Quality; and Factor 

D: Inadequacy of existing regulatory 

mechanisms, above). The Service is 

currently in consultation with the EPA 

to evaluate the protectiveness of criteria 

approved in EPA’s water quality 

standards for endangered and 

threatened species and their critical 

habitats as described in the 

Memorandum of Agreement that our 

agencies signed in 2001 (66 FR 11201, 

February 22, 2001). Other factors that 

can potentially alter water quality are 

droughts and periods of low flow, 

nonpoint source runoff from adjacent 

land surfaces (for example, excessive 

amounts of nutrients, pesticides, and 

sediment), and random spills or 

unregulated discharge events. This 

could be particularly harmful during 

drought conditions when flows are 

depressed and pollutants are more 

concentrated. Therefore, adequate water 

quality is essential for normal behavior, 

growth, and viability during all life 

stages of the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail. 

Sites for Breeding, Reproduction, or 

Rearing 

Pleurocerid snails require clean hard 

surfaces, such as gravel, cobble, boulder, 

or bedrock, for laying eggs and for 

survival of juveniles (Bogan et al. 1995, 

p. 251). Excessive fine sediments or 

dense growth of filamentous algae can 

restrict or eliminate spawning sites and 

expose juveniles to entrainment (being 

swept away) or predation. Geomorphic 

instability may result in entrainment 

and loss of eggs by scouring currents or 

burial of eggs by excessive deposition. 

Therefore, stable shoals with low 

amounts of filamentous algae are 

essential to the conservation of the 

interrupted rocksnail and rough 

hornsnail. 

Freshwater mussels require a host fish 

for transformation of larval mussels 

(glochidia) to juvenile mussels 

(Williams et al. 2008, p. 68), and 

presence of the appropriate host fish is 

essential to the conservation of the 

Georgia pigtoe. The specific fish host(s) 

for the Georgia pigtoe is currently 

unknown. However, other species of 

mussels in the genus Pleurobema are 

known to parasitize various species of 

chubs, minnows, stonerollers, and other 

stream-adapted fish species (Haag and 

Warren 2003, p. 85). 

Juvenile Georgia pigtoe mussels 

require interstitial shoal habitats for 

growth and survival. Excessive 

sediments or dense growth of 

filamentous algae can expose juvenile 

mussels to entrainment or predation and 

be detrimental to the survival of 

juvenile mussels (Hartfield and 

Hartfield 1996, p. 373). Geomorphic 

instability can result in the loss of 

interstitial habitats and juvenile mussels 

due to scouring or deposition (e.g., 

Hartfield 1993, pp. 132–139). Therefore, 

stable shoals with low to moderate 

amounts of filamentous algae growth are 

essential to the conservation of the 

Georgia pigtoe. 

PCEs for the Georgia pigtoe, Interrupted 

Rocksnail, and Rough Hornsnail 

Based on the above needs and our 

current knowledge of the life history, 

biology, and ecology of the species, we 

have determined that the Georgia 

pigtoe’s PCEs are: 

(1) Geomorphically stable stream and 

river channels and banks (channels that 

maintain lateral dimensions, 

longitudinal profiles, and sinuosity 

patterns over time without an aggrading 

or degrading bed elevation). 

(2) A hydrologic flow regime (the 

magnitude, frequency, duration, and 

seasonality of discharge over time) 

necessary to maintain benthic habitats 

where the species is found. Unless other 

information becomes available, existing 

conditions at locations where the 

species occurs will be considered as 

minimal flow requirements for survival. 

(3) Water quality, including 

temperature, pH, hardness, turbidity, 

oxygen content, and chemical 

characteristics necessary for normal 

behavior, growth, and viability of all life 

stages. 

(4) Sand, gravel, cobble, boulder, or 

bedrock substrates with low to moderate 

amounts of fine sediment and attached 

filamentous algae. 

(5) The presence of fish host(s) for the 

Georgia pigtoe (currently unknown). 

Diverse assemblages of native chubs, 

minnows, stonerollers, and other 

stream-adapted fish species will serve as 

a potential indication of presence of 

host fish. 

The PCEs required for the interrupted 

rocksnail are: 

(1) Geomorphically stable stream and 

river channels and banks (channels that 

maintain lateral dimensions, 

longitudinal profiles, and sinuosity 

patterns over time without an aggrading 

or degrading bed elevation). 

(2) A hydrologic flow regime (the 

magnitude, frequency, duration, and 

seasonality of discharge over time) 

necessary to maintain benthic habitats 

where the species is found. Unless other 

information becomes available, existing 

conditions at locations where the 

species occurs will be considered as 

minimal flow requirements for survival. 

(3) Water quality, including 

temperature, pH, hardness, turbidity, 

oxygen content, and chemical 

characteristics necessary for normal 

behavior, growth, and viability of all life 

stages. 

(4) Sand, gravel, cobble, boulder, or 

bedrock substrates with low to moderate 

amounts of fine sediment and attached 

filamentous algae. 

The PCEs required for the rough 

hornsnail are: 

(1) Geomorphically stable stream and 

river channels and banks (channels that 

maintain lateral dimensions, 

longitudinal profiles, and sinuosity 

patterns over time without an aggrading 

or degrading bed elevation). 

(2) A hydrologic flow regime (the 

magnitude, frequency, duration, and 

seasonality of discharge over time) 

necessary to maintain benthic habitats 

where the species are found. Unless 

other information becomes available, 

existing conditions at locations where 

the species occur will be considered as 

minimal flow requirements for survival. 

(3) Water quality, including 

temperature, pH, hardness, turbidity, 

oxygen content, and chemical 

characteristics necessary for normal 

behavior, growth, and viability of all life 

stages. 

(4) Sand, gravel, cobble, boulder, 

bedrock, or mud substrates with low to 

moderate amounts of fine sediment and 

attached filamentous algae. 

This critical habitat designation is 

designed for the conservation of the 

physical and biological features 

essential to the life-history functions 

that were the basis for the determination 

of endangered status and the areas 

containing those features (that is, the 

PCEs in the appropriate spatial 

arrangement and quantity). Because not 

all life history functions require all the 

PCEs, not all PCEs may be present 

throughout the critical habitat units. 

Units are designated based on 

sufficient PCEs being present to support 

at least one of the species’ life history 

functions. Some areas contain all PCEs 

and support multiple life processes, 

while some areas may contain only a 

portion of the PCEs necessary to support 

the species’ particular use of that 

habitat. 


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Special Management Considerations or 

Protections 

When designating critical habitat, we 

assess whether the areas within the 

geographical area occupied by the 

species at the time of listing contain 

features that are essential to the 

conservation of the species and whether 

those features may require special 

management considerations or 

protections. All of the critical habitat 

units identified for these three species 

below, with the exception of a portion 

of Unit RH 1, have been designated as 

critical habitat for other mollusk species 

that are already listed under the Act. 

None of the areas are presently under 

special management or protection 

provided by a legally operative 

management plan or agreement for the 

conservation of the interrupted 

rocksnail, rough hornsnail, or Georgia 

pigtoe. Various activities in or adjacent 

to each of the critical habitat units 

described below may affect one or more 

of the PCEs. Some of these activities 

include, but are not limited to, those 

discussed in the Summary of Factors 

Affecting the Species, above. For 

example, three of the units described 

below (Units IR 1, IR 2, and RH 1 

(which includes IR 3)) may require 

special management considerations due 

to detrimental effects of hydropower 

generation or lack of minimum flow 

releases from dams (see Factor A: Dams 

and Impoundments, above). Features in 

all of the critical habitat units may 

require special management due to 

threats posed by land-use runoff and 

point- and nonpoint-source water 

pollution (see Factor A: Water and 

Habitat Quality, and Factor D: 

Inadequacy of existing regulatory 

mechanisms, above). Other activities 

that may affect PCEs in the critical 

habitat units include those listed in the 

Effects of Critical Habitat Designation 

section as Federal Activities that may 

affect critical habitat and require 

consultation, below. 

Criteria Used To Identify Critical 

Habitat 

We are designating as critical habitat 

all stream channels that are currently 

occupied by the species, as well as some 

specific areas not currently occupied 

but that were historically occupied, 

because we have determined that these 

additional areas are essential for the 

conservation of the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail, and that designating only 

occupied habitat is not sufficient to 

conserve each of these species. 

When identifying critical habitat 

boundaries, we make every effort to 

avoid including developed areas such as 

lands covered by buildings, pavement, 

and other structures because such lands 

usually lack PCEs for endangered or 

threatened species. Areas identified as 

critical habitat for the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail, below, include only stream 

channels within the ordinary high water 

line and do not contain any developed 

areas or structures. 

Occupied Stream Reaches Designated as 

Critical Habitat 

We have defined occupied habitat as 

those stream reaches known to be 

currently occupied by the Georgia 

pigtoe, interrupted rocksnail, or rough 

hornsnail. We used information from 

surveys and reports prepared by the 

U.S. Geological Survey, the Alabama 

Department of Conservation and Natural 

Resources, the Tennessee Aquarium, 

Alabama Geological Survey, Auburn 

University, University of Alabama, and 

Service field records to identify the 

specific locations occupied by the 

Georgia pigtoe, interrupted rocksnail, or 

rough hornsnail. 

Currently, occupied habitat for each 

of the three species is extremely limited 

and isolated. The Georgia pigtoe persists 

only in a restricted series of shoals in 

the Conasauga River (Johnson and Evans 

2000, p. 106). The interrupted rocksnail 

naturally survives in a short reach of the 

Oostanaula River in Gordon and Floyd 

Counties, Georgia, and population 

reintroductions have been attempted 

into a shoal of the Lower Coosa River, 

Elmore County, Alabama (ADCNR 2004, 

p. 33). The rough hornsnail is known 

from two small, localized, and isolated 

populations: Yellowleaf Creek, Shelby 

County, Alabama, and a short reach of 

the Lower Coosa River, Elmore County, 

Alabama (Sides 2005, p. 40). We believe 

that all currently occupied areas contain 

features essential to the conservation of 

these species. With such limited 

distribution, each of these species is at 

a high risk of extinction and highly 

susceptible to stochastic events. 

Unoccupied Stream Reaches Designated 

as Critical Habitat 

The streams not currently occupied 

that we are designating as critical 

habitat were all historically occupied. 

We believe that the designation of 

additional areas not known to be 

currently occupied by the Georgia 

pigtoe, interrupted rocksnail, or rough 

hornsnail is essential for their 

conservation because: 

(1) The range of each species has been 

severely curtailed, occupied habitats are 

limited and isolated, and population 

sizes are extremely small for each 

species. While occupied units provide 

habitat for current populations, they are 

at high risk of extirpation and extinction 

from stochastic events, whether periodic 

natural events or existing or potential 

human-induced events (see Summary of 

Factors Affecting the Species). The 

inclusion of essential unoccupied areas 

will provide habitat for population 

reintroduction and will decrease the 

risk of extinction for each species. 

(2) The essential unoccupied areas 

may offer habitat that is superior to that 

in the occupied units (the potential 

viability of the mollusks in unoccupied 

units may be higher) because the 

essential unoccupied areas may be faced 

with fewer and more easily treated 

threats than the occupied units (see 

discussion under Factor A: Dams and 

Impoundments). 

(3) The protection of PCEs in 

currently occupied areas is directly 

related to conditions in adjacent 

unoccupied stream reaches (such as the 

Oostanaula and Lower Coosa Rivers). 

Based on the best scientific data 

available, we believe that areas that are 

not currently occupied by the Georgia 

pigtoe, interrupted rocksnail, or rough 

hornsnail are essential for their 

conservation. 

Length of Occupied Stream Reaches 

Following the identification of 

occupied stream reaches, the next step 

was to delineate the length of upstream 

and downstream reaches of known 

occupied areas to determine the length 

of stream reaches that are needed for the 

conservation of the populations for each 

species. All known occurrences for each 

species are extremely localized, and rare 

aquatic snails and mussels can be 

difficult to locate. In addition, creek and 

river habitats are highly dependent 

upon upstream and downstream 

channel habitat conditions for their 

maintenance. Therefore, where more 

than one occurrence record of a 

particular species was found within a 

stream reach, we considered the entire 

reach between the uppermost and 

lowermost locations as occupied 

habitat, as discussed below. 

Georgia pigtoe 

The Georgia pigtoe is currently known 

to survive only in a 52-km (32-mi) reach 

of the Upper Conasauga River extending 

from Polk County, Tennessee, 

downstream into Murray and Whitfield 

Counties, Georgia (Johnson and Evans 

2000, p. 106; Evans 2001, pp. 33–34). 

The Georgia pigtoe has been recently 

collected from three shoals within this 

reach: one located at each end of the 

reach, and one additional site in the 

lower third of the reach. Other shoals 


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within the reach continue to be 

inhabited by a diverse mussel 

community, including the federally 

endangered triangular kidneyshell and 

southern pigtoe and the threatened finelined pocketbook. These species 

historically co-occurred in the same 

shoal habitats with the Georgia pigtoe, 

and their persistence indicates the 

presence of PCEs for the pigtoe 

throughout the reach. Therefore, we 

consider the entire 52-km (32-mi) reach 

between the uppermost and lowermost 

recent collection sites for the Georgia 

pigtoe as occupied habitat. In the area 

identified as critical habitat below, 

boundaries extend from the nearest 

downstream landmark at both ends of 

the reach. 

Interrupted rocksnail 

The interrupted rocksnail is known to 

survive in several shoals along a 12-km 

(7.4-mi) reach of the Oostanaula River 

between Ship Island and the confluence 

of Armuchee Creek, Gordon and Floyd 

counties, Georgia (Johnson and Evans 

2000, pp. 45–46; Johnson and Evans 

2001, pp. 2, 25). Although rocksnails 

live attached to the stream bottom, they 

are small and often difficult to locate 

when their population numbers are low. 

Therefore, we consider the reach of the 

Oostanaula River between Ship Island 

and the confluence of Armuchee Creek 

as habitat occupied by interrupted 

rocksnail. Attempts to reintroduce the 

species into the Lower Coosa River, 

Elmore County, Alabama, have also 

been made by the ADCNR. ADCNR 

attempted to reintroduce the interrupted 

rocksnail into Gray Island Shoals in the 

Lower Coosa River, about 3.2 km (2 mi) 

below Jordan Dam, Elmore County, 

Alabama. Although we do not yet know 

if this reintroduced population is viable, 

it is within the historical range of the 

interrupted rocksnail, and we are 

considering the 1-km (0.6-mi) reach 

encompassing Gray Island Shoals in the 

Lower Coosa River as occupied habitat. 

Rough hornsnail 

The rough hornsnail is known to 

survive at only two locations, 

Yellowleaf Creek and the Lower Coosa 

River. At the time we proposed these 

areas as critical habitat (74 FR 31113) 

for the rough hornsnail, we considered 

only a 3.2-km (2-mi) reach of Yellowleaf 

Creek, Shelby County, Alabama, as 

occupied by the species. A snail survey 

conducted by a Service biologist and 

others (Powell in litt. 2009) has since 

found the species throughout the 

designated area. Therefore, we consider 

the entire designated 6.4-km (4-mi) 

reach of Yellowleaf Creek as occupied 

by the rough hornsnail. 

Collections during the 1990s from the 

Lower Coosa River, Elmore County, 

Alabama, show the rough hornsnail 

extended from the shoals below Jordan 

Dam, downstream to just below the Fall 

Line at Wetumpka, Alabama (FLMNH in 

litt. 2006). Therefore, we consider this 

14-km (8-mi) reach as habitat occupied 

by the rough hornsnail. 

Stream Reaches Not Currently Occupied 

In identifying unoccupied stream 

reaches that are essential to the 

conservation of each species (Georgia 

pigtoe, interrupted rocksnail, and rough 

hornsnail), we first considered the 

availability of potential habitat 

throughout their historical ranges that 

may be suitable for the survival and 

persistence of each species. A large 

proportion of the streams that formerly 

supported each species have been 

modified by dams and their impounded 

waters, and we eliminated these areas 

from consideration, because none of 

these species can survive under the 

modified conditions (see Primary 

Constituent Elements (PCEs) section, 

above). We also eliminated from 

consideration free-flowing streams 

without any historical records of 

occurrence. We eliminated from 

consideration other streams with 

historical occurrence records because of 

limited habitat availability, isolation, 

degraded habitat, or low management 

value or potential (such as Coosawattee 

River and Etowah River). 

All of the areas identified as critical 

habitat that are currently not known to 

be occupied meet one or more of the 

following criteria: 

(1) The stream habitat contains 

sufficient PCEs (for example, such 

characteristics as geomorphically stable 

channels, perennial water flows, 

adequate water quality, and appropriate 

benthic substrates) to support lifehistory functions of the mollusks (all 

unoccupied critical habitat units); 

(2) The stream supports diverse 

aquatic molluscan communities, 

including the presence of closely related 

species requiring PCEs similar to the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail (all unoccupied 

critical habitat units); 

(3) The stream reaches are adjacent to 

currently occupied areas where there is 

potential for natural dispersal and 

reoccupation by the Georgia pigtoe, 

interrupted rocksnail, or rough 

hornsnail (Oostanaula River, Lower 

Coosa River, and Yellowleaf Creek); 

(4) The stream reaches lack major 

anthropogenic disturbance (Hatchet 

Creek); 

(5) Areas are remote from currently 

occupied areas and have experienced 

improvements in water quality or 

quantity during the past decades due to 

implementation of minimum flows 

below dams, changes in adjacent land 

uses, or implementation of the Clean 

Water Act (Coosa River below Weiss 

Dam and Jordan Dam, Terrapin Creek, 

and Hatchet Creek); and 

(6) The stream reaches have potential 

for reoccupation by the species through 

future reintroduction efforts (all 

unoccupied critical habitat units). 

Based on the above factors, all 

unoccupied stream reaches included in 

the critical habitat designations for each 

of these three species are essential to 

their conservation. 

Georgia Pigtoe 

We identified 101 km (63 mi) of 

habitat in two stream reaches that are 

currently unoccupied by the Georgia 

pigtoe and that meet several of the 

criteria for designation as critical 

habitat. Historical records of Georgia 

pigtoe occur from the Coosa River near 

the present location of Weiss Dam and 

from Terrapin Creek, from its 

confluence with the Coosa River 

upstream to the vicinity of Alabama 

Highway 9. Terrapin Creek flows into 

the Coosa River approximately 11 km (7 

mi) below Weiss Dam in Cherokee 

County, Alabama. Together these two 

confluent stream reaches encompass 35 

km (22 mi) of stream habitat that meet 

Criteria 1, 2, 5, and 6 listed above in this 

section. Terrapin Creek and this short 

reach of the Coosa River support diverse 

mollusk and fish communities. Water 

quality in Terrapin Creek meets current 

State criteria for Fish and Wildlife. The 

Mobile River Basin Mollusk Restoration 

Committee (2009, p. 22) recognizes this 

reach of the Coosa River and Terrapin 

Creek as an appropriate reintroduction 

site for the Georgia pigtoe. Based on the 

information we have to date, which 

does not necessarily suggest there is an 

increased probability of Georgia pigtoe 

conservation in specific areas within the 

reach, we are designating the entire 

reach of Terrapin Creek and the Coosa 

River as critical habitat. 

Historical records of Georgia pigtoe 

occur from an approximately 66-km (41- 

mi) reach of Hatchet Creek between Clay 

County Road 4 downstream to the 

confluence with Swamp Creek in Coosa 

County, Alabama. This stream reach 

meets Criteria 1, 2, 4, 5, and 6 listed 

above in this section and has been 

identified by the Mobile River Basin 

Mollusk Restoration Committee (2008, 

p. 40) as having high conservation 

potential for the reintroduction of 

imperiled mollusks. Hatchet Creek 

supports diverse mollusk and fish 

communities and has been designated 


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as an Outstanding Alabama Water, the 

highest protective classification 

assigned by the State. Based on the 

information we have to date, which 

does not necessarily suggest there is an 

increased probability of Georgia pigtoe 

conservation in specific areas within the 

reach, we are designating the entire 

reach of Hatchet Creek as critical 

habitat. 

Interrupted Rocksnail 

We identified 88 km (55 mi) of habitat 

in three stream reaches that are 

currently unoccupied by the interrupted 

rocksnail and that meet several of the 

criteria for designation as unoccupied 

habitat. The Coosa River from Weiss 

Dam to just below the confluence of 

Terrapin Creek (11 km (7 mi)) is within 

the historical range of the interrupted 

rocksnail, and meets Criteria 1, 2, 5, and 

6 listed above in this section. Several 

mollusk species requiring similar PCEs 

currently inhabit a portion of the reach. 

Projected minimum flows (Weiss 

Bypass Working Group 2005, pp. 6–8) 

will improve PCEs in the remainder of 

the reach, and reservoir-stored water 

will provide protection from nonpoint 

source pollution and reduce the 

potential of stochastic threats. The 

Mobile River Basin Mollusk Restoration 

Committee (2008, p. 53) recognizes this 

reach of the Coosa River as an 

appropriate reintroduction site for 

interrupted rocksnail. 

The interrupted rocksnail is currently 

known to inhabit shoals along a 12-km 

(7.4-mi) reach of the Oostanaula River 

between Ship Island and the Confluence 

of Armuchee Creek, Gordon and Floyd 

Counties, Georgia. However, appropriate 

habitat extends approximately 49 km 

(30 mi) above Ship Island to the 

Conasuaga-Coosawattee confluence in 

Gordon County, Georgia, and 

approximately 16 km (10 mi) below the 

confluence of Armuchee Creek to the 

Georgia Highway 1 Loop in Floyd 

County, Georgia. This unoccupied area 

encompasses an additional 65 km (40 

mi) of river habitat that meets Criteria 1, 

2, 3, and 6 listed above in this section. 

The unoccupied upstream and 

downstream reaches of the Oostanaula 

River contain one or more of the PCEs 

required by the species, including 

geomorphically stable channels and 

natural flows. They are adjacent to areas 

currently occupied by interrupted 

rocksnail, and there is potential for 

natural dispersal and re-occupation by 

the interrupted rocksnail. These areas 

are also currently occupied by other 

mollusk species with similar habitat 

requirements. 

The Lower Coosa River below Jordan 

Dam is within the historical range of the 

interrupted rocksnail, and a small 

population of the species has been 

reintroduced into a shoal there (ADCNR, 

p. 33). Apparently suitable habitat 

extends approximately 13 km (8 mi) 

from the tailwaters of Jordan Dam to 

Alabama Highway 111 in Elmore 

County, Alabama. This reach meets 

Criteria 1, 2, 3, 5, and 6 listed above in 

this section. The steep river gradient 

below the dam to the Fall Line at 

Alabama Highway 111 in Wetumpka 

results in the presence of numerous 

high-quality and stable shoals and pools 

characteristic of habitats formerly 

inhabited by the interrupted rocksnail. 

The reach is occupied by other species 

of pleurocerid snails, as well as a 

diverse mussel fauna, indicating the 

presence of PCEs in this reach. 

Minimum flows that have been 

established from Jordan Dam have 

eliminated historical threats, such as 

seasonal loss of flow and low dissolved 

oxygen levels. The Mobile River Basin 

Mollusk Restoration Committee (2008, 

p. 53) recognizes this reach of the Coosa 

River as an appropriate reintroduction 

site for interrupted rocksnail, and the 

ADCNR has initiated attempts to 

reintroduce the species to the reach. 

Rough Hornsnail 

We identified 7 km (4 mi) of habitat 

that is unoccupied by the rough 

hornsnail and that meets Criteria 1, 2, 3, 

and 6 listed above in this section. The 

species inhabits a 14-km (8-mi) reach of 

the Lower Coosa River below Jordan 

Dam; however, appropriate habitat 

extends an additional 7 km (4 mi) 

downstream of currently occupied 

areas. This stream reach is available for 

natural recolonization and contains one 

or more of the PCEs required by the 

rough hornsnail, including a 

geomorphically stable channel and 

adequate water quality and substrate, as 

indicated by the presence of closely 

related pleurocerids and other mollusk 

species with similar habitat 

requirements. 

Critical Habitat Designation 

We are designating three units as 

critical habitat for the Georgia pigtoe 

(GP 1, GP 2, and GP 3), three units for 

interrupted rocksnail (IR 1, IR 2, and IR 

3), and two units for rough hornsnail 

(RH 1 and RH 2). The critical habitat 

areas described below constitute our 

best assessment of areas that currently 

meet the definition of critical habitat for 

the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail. Table 1 

identifies the units for each species; 

shows the occupancy of the units, the 

approximate extent designated as 

critical habitat for the Georgia pigtoe 

(GP), interrupted rocksnail (IR), and 

rough hornsnail (RH); and provides 

information on the ownership of lands 

within the designated units. Critical 

habitat includes only the stream 

channel within the ordinary high water 

line. In Alabama and Georgia, the State 

owns navigable stream bottoms within 

the ordinary high water line, and all 

designated units in Alabama and 

Georgia are considered navigable. In 

Tennessee, the riparian landowner owns 

the stream bottom to the middle of the 

channel. 

TABLE 1—OCCUPANCY AND OWNERSHIP OF CRITICAL HABITAT UNITS FOR GEORGIA PIGTOE (GP), INTERRUPTED

ROCKSNAIL (IR), AND ROUGH HORNSNAIL (RH) 

Unit Location Occupancy 

Private 

ownership 

river 

kilometers 

(miles) 

State 

ownership 

river 

kilometers 

(miles) 

GP 1 .. Conasauga River ...................................................................... Occupied .................................................. 5 (3) 47 (29) 

GP 2 .. Terrapin Creek and Coosa River .............................................. Unoccupied .............................................. 0 1 35 (22) 

GP 3 .. Hatchet Creek ........................................................................... Unoccupied .............................................. 0 66 (41) 

Total 5 (3) 148 (92) 

IR 1 .... Coosa River .............................................................................. Unoccupied .............................................. 0 1 11 (7) 

IR 2 .... Oostanaula River ...................................................................... Occupied .................................................. 0 12 (7.4) 

Unoccupied .............................................. 0 65 (40.6) 


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TABLE 1—OCCUPANCY AND OWNERSHIP OF CRITICAL HABITAT UNITS FOR GEORGIA PIGTOE (GP), INTERRUPTED

ROCKSNAIL (IR), AND ROUGH HORNSNAIL (RH)—Continued 

Unit Location Occupancy 

Private 

ownership 

river 

kilometers 

(miles) 

State 

ownership 

river 

kilometers 

(miles) 

IR 3 .... Lower Coosa River ................................................................... Occupied .................................................. 0 21 (0.6) 

Unoccupied .............................................. 0 2 12 (7.4) 

Total 0 101 (63) 

RH 1 .. Lower Coosa River ................................................................... Occupied .................................................. 0 2 14 (9) 

Unoccupied .............................................. 0 7 (4) 

RH 2 .. Yellowleaf Creek ....................................................................... Occupied .................................................. 0 6.4 (4) 

Unoccupied .............................................. 0 0 

Total 0 27.4 (17) 

1 IR 1 overlaps in part with GP 2. 

2 IR 3 overlaps in part with RH 1. See Unit descriptions, below. 

We present brief descriptions of all 

units and reasons why they meet the 

definition of critical habitat for each 

species below. The critical habitat units 

include the creek and river channels 

within the ordinary high water line. For 

this purpose, we applied the ordinary 

high water line definition found at 33 

CFR 329.11, which is defined for 

nontidal rivers to be the line on the 

shore established by the fluctuations of 

water and indicated by physical 

characteristics, such as a clear, natural 

line impressed on the bank; shelving; 

changes in the character of soil; 

destruction of terrestrial vegetation; the 

presence of litter and debris; or other 

appropriate means that consider the 

characteristics of the surrounding areas. 

For each stream reach identified as a 

critical habitat unit, the upstream and 

downstream boundaries are described 

generally below; more precise estimates 

are provided in the Regulation 

Promulgation section at the end of this 

final rule. 

Unit GP 1: Conasauga River, Bradley 

and Polk Counties, Tennessee, and 

Murray and Whitfield Counties, Georgia 

Unit 1 for the Georgia pigtoe includes 

52 km (32 mi) of the Upper Conasauga 

River from the confluence of 

Minnewaga Creek near Willis Springs, 

Polk County, Tennessee, downstream to 

U.S. Highway 76 in Murray and 

Whitfield Counties, Georgia. Critical 

habitat includes the stream channel 

within the ordinary high water line 

only. In Tennessee, the riparian 

landowner owns the stream bottom to 

the middle of the channel. Therefore, 5 

km (3 mi) of GP 1 in Tennessee is 

privately owned. In Georgia, the State 

owns navigable stream bottoms within 

the ordinary high water line, and the 

Conasauga River is considered 

navigable. Therefore, the State of 

Georgia owns 47 km (29 mi) of Unit GP 

1. 

The Georgia pigtoe has been collected 

from three shoals within the reach of the 

Conasauga River identified as GP 1, one 

located at each end of the reach and one 

site in between (Johnson and Evans 

2000, p. 106; Evans 2001, pp. 33–34). 

Therefore, we consider the entire reach 

of the Conasauga River that composes 

GP 1 as occupied. Other shoals within 

the reach continue to be inhabited by a 

diverse mussel community, including 

the endangered triangular kidneyshell 

and southern pigtoe and the threatened 

fine-lined pocketbook. These species 

historically co-occurred in the same 

shoal habitats with the Georgia pigtoe, 

they have similar habitat requirements, 

and their persistence indicates the 

presence of PCEs 1, 2, 3, and 4 for the 

Georgia pigtoe. The persistence of the 

Georgia pigtoe within three shoals of 

this reach also indicates the presence of 

an appropriate fish host (PCE 5). This 

small population of Georgia pigtoe is at 

a high risk of extinction due to changes 

in flow, habitat or water quality, and 

stochastic events such as drought. 

Threats to the Georgia pigtoe and its 

habitat that may require special 

management of the PCEs include the 

potential of anthropogenic activities 

(such as channelization, impoundment, 

and channel excavation) that could 

cause aggradation or degradation of the 

channel bed elevation or significant 

bank erosion; the potential of significant 

changes in the existing flow regime due 

to such activities as impoundment, 

water diversion, or water withdrawal; 

the potential of significant alteration of 

water chemistry or water quality; and 

the potential of significant changes in 

stream bed material composition and 

quality by activities such as 

construction projects, livestock grazing, 

timber harvesting, off-road vehicle use, 

and other watershed and floodplain 

disturbances that release sediments or 

nutrients into the water. 

Unit GP 2: Terrapin Creek and Coosa 

River, Cherokee County, Alabama 

Unit 2 for the Georgia pigtoe includes 

24 km (15 mi) of Terrapin Creek from 

Alabama Highway 9 downstream to its 

confluence with the Coosa River, and 11 

km (7 mi) of the Coosa River from Weiss 

Dam downstream to approximately 1.6 

km (1 mi) below the confluence of 

Terrapin Creek in Cherokee County, 

Alabama. The State of Alabama owns 

navigable stream bottoms within the 

ordinary high water line, and both 

Lower Terrapin Creek and the Coosa 

River are considered navigable streams. 

The Georgia pigtoe is not currently 

known to occur in Terrapin Creek or the 

Coosa River. However, Unit 2 is 

essential to the conservation of the 

Georgia pigtoe due to the high potential 

for stochastic events in the Conasauga 

River (the only extant population of 

Georgia pigtoe), and the need to reestablish the species within other 

portions of its historical range in order 

to reduce threats from stochastic events. 

Lower Terrapin Creek and the Coosa 

River are within the species’ historical 

range, and we consider them to be 

essential to the conservation of the 

Georgia pigtoe. Terrapin Creek flows 

into the Coosa River below Weiss Dam. 

Terrapin Creek continues to support a 

diverse mollusk assemblage, including 

the endangered southern pigtoe, a 

closely related species that co-occurs 

with the Georgia pigtoe in the 

Conasauga River, indicating the 

presence of PCEs 1, 2, 3, and 4. The 


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endangered southern clubshell, the 

threatened fine-lined pocketbook, and 

other mussel and snail species requiring 

PCEs 1, 2, 3, and 4 similar to the Georgia 

pigtoe continue to survive in the Coosa 

River just below the confluence of 

Terrapin Creek. Additionally, a diverse 

fish fauna, including potential fish hosts 

for the Georgia pigtoe (PCE 5), is known 

from Terrapin Creek and Coosa River. 

Minimum flows from Weiss Dam into 

the Coosa River will be implemented 

upon completion of the Alabama Power 

Company Coosa River hydropower 

relicensing process with FERC (Weiss 

Bypass Working Group 2005, pp. 6–8), 

which is currently in progress. These 

minimum flows will improve the PCEs 

necessary for the survival of the Georgia 

pigtoe in the Coosa River, particularly 

above the confluence with Terrapin 

Creek. Because the minimum flows will 

originate from the large reservoir 

impounded by Weiss Dam, there is little 

threat of nonpoint source pollution and 

reduced potential of stochastic threats, 

such as drought and spills. ADCNR 

recognizes this reach of the Coosa River 

as having high conservation potential 

for imperiled mollusks in Alabama and 

is planning to reintroduce imperiled 

mollusks, including the Georgia pigtoe, 

following implementation of minimum 

flows. Over the past few decades, 

changes in land uses, use of best 

management practices for agriculture 

and forestry activities in the watershed, 

and implementation of State water 

quality standards resulted in improved 

water quality and shoal habitats in 

Terrapin Creek. The Mobile River Basin 

Mollusk Restoration Committee (2008, 

p. 40) recognizes Terrapin Creek as an 

appropriate reintroduction opportunity 

for the Georgia pigtoe. 

Unit GP 3: Hatchet Creek, Coosa and 

Clay Counties, Alabama 

Unit 3 for the Georgia pigtoe includes 

approximately 66 km (41 mi) of Hatchet 

Creek, extending from Clay County 

Road 4, Clay County, downstream to the 

confluence of Swamp Creek at Coosa 

County Road 29, Coosa County, 

Alabama. The State of Alabama owns 

navigable stream bottoms within the 

ordinary high water line, and Hatchet 

Creek is considered navigable. 

The Georgia pigtoe does not currently 

occupy Hatchet Creek. However, 

historical records of the species show its 

presence in this stream from the 

stream’s confluence with the Coosa 

River, Coosa County, upstream into Clay 

County, Alabama. An extensive reach of 

Hatchet Creek is occupied by the 

threatened fine-lined pocketbook, along 

with other mollusk species that 

currently or historically co-occur with 

Georgia pigtoe, indicating the presence 

of PCEs 1, 2, 3, and 4. A diverse fish 

fauna, including several potential fish 

hosts for the pigtoe (PCE 5), is also 

known to inhabit Hatchet Creek. Water 

quality and shoal habitats in this stream 

have improved relative to past historical 

conditions due to changes in land uses, 

implementation of best management 

practices in agriculture and forestry 

activities in the watershed, and 

implementation of State water quality 

standards. Due to these improvements, 

Hatchet Creek has been designated as an 

Outstanding Alabama Water, which also 

provides for increased water quality 

protections. The Mobile River Basin 

Mollusk Restoration Committee (2008, 

p. 40) recognizes Hatchet Creek as 

having high conservation potential for 

reintroduction of the Georgia pigtoe. 

Re-establishing Georgia pigtoe in 

Hatchet Creek will significantly reduce 

the level of stochastic threats to the 

species’ survival and is essential to the 

conservation of the species. We do not 

know which specific shoals or reaches 

of Hatchet Creek may be capable of 

supporting the Georgia pigtoe. 

Therefore, we have designated all 

apparently suitable habitat within the 

historical range of the species in Hatchet 

Creek as critical habitat essential to the 

conservation of Georgia pigtoe. 

Unit IR 1: Coosa River, Cherokee 

County, Alabama (overlaps in part with 

GP 2, described above) 

Unit 1 for the interrupted rocksnail 

includes approximately 11 km (7 mi) of 

the Coosa River extending from Weiss 

Dam downstream to about 1.6 km (1 mi) 

below the confluence of Terrapin Creek, 

Cherokee County, Alabama. The State of 

Alabama owns navigable stream 

bottoms within the ordinary high water 

line, and the Coosa River is considered 

navigable. 

The interrupted rocksnail historically 

inhabited the Coosa River in Cherokee 

County. Although the species does not 

currently occupy the area, Unit 1 is 

essential to the conservation of the 

interrupted rocksnail due to the high 

degree of stochastic threats to the single 

surviving population in the Ostanaula 

River and the need to re-establish the 

species within other portions of its 

historical range. The presence of the 

endangered southern clubshell, the 

threatened fine-lined pocketbook, and 

other mussel and snail species in the 

Coosa River at and below the confluence 

of Terrapin Creek indicates the presence 

of PCEs 1, 2, 3, and 4 for the interrupted 

rocksnail. 

Minimum flows from Weiss Dam into 

the Coosa River will be implemented 

upon completion of the Alabama Power 

Company Coosa River hydropower 

relicensing process with FERC (Weiss 

Bypass Working Group 2005, pp. 6–8) 

currently in progress. These minimum 

flows will improve the PCEs necessary 

for the survival of the interrupted 

rocksnail in about 11 km (7 mi) of the 

Coosa River, between Weiss Dam 

downstream to the confluence with 

Terrapin Creek. Implementation of 

minimum flows from Weiss Dam (Weiss 

Bypass Working Group 2005, pp. 6–8) 

will improve PCEs necessary for the 

survival of the interrupted rocksnail. 

The majority of flow into the reach 

above the confluence of Terrapin Creek 

originates from Weiss Dam. Therefore, 

there is little threat of nonpoint source 

pollution, and reduced potential of 

stochastic threats such as drought and 

spills. ADCNR recognizes this reach as 

having high conservation potential for 

imperiled mollusks in Alabama and is 

planning to reintroduce imperiled 

mollusk species, including the 

interrupted rocksnail, into the reach 

following initiation of minimum flows. 

Re-establishing the interrupted 

rocksnail into the Coosa River will 

significantly reduce stochastic threats to 

the survival of the species and is 

essential to its conservation. 

Unit IR 2: Oostanaula River, Gordon 

and Floyd Counties, Georgia 

Unit 2 for the interrupted rocksnail 

includes approximately 77 km (48 mi) 

of the Oostanaula River from the 

Conasauga–Coosawattee confluence in 

Gordon County, downstream to Georgia 

Highway 1 loop in Floyd County, 

Georgia. The State of Georgia owns 

navigable stream bottoms within the 

ordinary high water line, and the 

Oostanaula River is considered 

navigable. 

The interrupted rocksnail occupies 

shoals along a 12-km (7.4-mi) reach of 

the Oostanaula River, extending from 

the confluence of Johns Creek in Gordon 

and Floyd Counties, downstream to the 

confluence of Armuchee Creek in Floyd 

County, Georgia. Threats to the 

interrupted rocksnail and its habitat in 

the Oostanaula River that may require 

special management of the PCEs include 

the potential of activities (such as 

channelization, impoundment, and 

channel excavation) that could cause 

aggradation or degradation of the 

channel bed elevation or significant 

bank erosion; the potential of significant 

changes in the existing flow regime due 

to activities such as impoundment, 

hydropower generation, water 

diversion, or water withdrawal; the 

potential of significant alteration of 

water chemistry or water quality; and 

the potential of significant changes in 


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stream bed material composition and 

quality by activities such as 

construction projects, livestock grazing, 

timber harvesting, off-road vehicle use, 

and other watershed and floodplain 

disturbances that release sediments or 

nutrients into the water. 

Although there are no recent 

collections of the species from shoal 

habitats above and below the currently 

inhabited reach, these currently 

unoccupied areas contain three of the 

PCEs required by the species, including 

geomorphically stable stream channels, 

natural flows, and appropriate 

substrates (PCEs 1, 2, and 4). The 

presence of other mollusk species with 

similar habitat requirements as the 

interrupted rocksnail in this reach, 

including the endangered triangular 

kidneyshell, along with more common 

species of pleurocerid snails, also 

indicates the potentially suitable 

presence of appropriate water quality 

(PCE 3). Shoals within the 65 km (40.6 

mi) of currently unoccupied reaches of 

the Oostanaula River are available to 

natural recolonization of the species. 

Expanding the range of the interrupted 

rocksnail into adjacent shoals in the 

river would greatly reduce the degree of 

threat from stochastic events, and is 

essential to the conservation of the 

interrupted rocksnail. 

Unit IR 3: Lower Coosa River, Elmore 

County, Alabama 

Unit 3 for the interrupted rocksnail 

includes 13 km (8 mi) of the Lower 

Coosa River between Jordan Dam and 

Alabama Highway 111 in Elmore 

County, Alabama. The State of Alabama 

owns navigable stream bottoms within 

the ordinary high water line, and the 

Coosa River is considered navigable. 

The Lower Coosa River is within the 

historical range of the species, and a 

small population of the interrupted 

rocksnail has been reintroduced into a 

1-km (0.6-mi) portion of a shoal there 

(ADCNR 2004, p 33). However, this 

reintroduced population will likely 

require augmentations over several 

years before population size can reach 

self-sustainable levels. The remaining 

12 km (7.4 mi) of this reach, from Jordan 

Dam downstream to the Fall Line at 

Wetumpka, contains numerous highquality shoals and pools characteristic 

of the large river habitats historically 

occupied by the species. Several other 

species of pleurocerid snails, the 

endangered tulotoma snail, and a 

diverse mussel fauna are currently 

found throughout the reach, indicating 

the presence and suitability of PCEs 1, 

2, 3, and 4 for the interrupted rocksnail 

in this reach. Historical threats, 

including seasonal loss of flow and low 

dissolved oxygen, were eliminated in 

1990 by implementation of minimum 

flows from Jordan Dam by the Alabama 

Power Company. As noted, ADCNR 

recognizes the Lower Coosa River as an 

appropriate location for imperiled 

mollusk reintroductions and has begun 

efforts to reestablish the interrupted 

rocksnail into this reach. Due to the 

extremely limited distribution of the 

interrupted rocksnail and the high 

degree of stochastic threats to the single 

natural population, reestablishing the 

species in the Lower Coosa River is 

essential to the conservation of the 

interrupted rocksnail. 

Unit RH 1: Lower Coosa River, Elmore 

County, Alabama (overlaps in part with 

IR 3, described above) 

Unit 1 for the rough hornsnail 

includes 21 km (13 mi) of the Lower 

Coosa River extending from Jordan Dam, 

downstream to the confluence of the 

Tallapoosa River in Elmore County, 

Alabama. The State of Alabama owns 

navigable stream bottoms within the 

ordinary high water line, and the Coosa 

River is considered navigable. We 

believe PCEs 1, 2, 3, and 4 to be suitable 

throughout the reach, due to the 

presence of rough hornsnail colonies or 

other closely related pleurocerid snail 

species that are known to co-occur with 

the hornsnail and have similar habitat 

requirements. 

Early 1990 records of rough hornsnail 

from the reach of the Coosa River 

between Jordan Dam and the Fall Line 

(FLMNH in litt. 2006), and more recent 

records of the hornsnail extending 2 km 

(1.2 mi) below the Fall Line (Hartfield 

pers. obsv. 2001; Crow in litt. 2008), 

indicate an occupied range of 14 km (9 

mi) in the Lower Coosa River. An 

additional 7-km (4-mi) channel reach 

extending downstream to the 

confluence of the Tallapoosa River is 

not currently occupied. This 

downstream unoccupied area is 

available for natural recolonization, and 

contains PCEs 1, 2, 3, and 4, including 

a geomorphically stable channel, and 

adequate flow, water quality, and 

substrate, as indicated by the presence 

of closely related pleurocerids and other 

mollusk species with similar habitat 

requirements. Expanding the range of 

rough hornsnail into the currently 

unoccupied downstream habitat would 

reduce the level of stochastic threats to 

the species, and is essential to its 

conservation. 

Threats to the rough hornsnail and its 

habitat in the Coosa River that may 

require special management of the PCEs 

include the potential of activities (such 

as channelization, impoundment, and 

channel excavation) that could cause 

aggradation or degradation of the 

channel bed elevation or significant 

bank erosion; the potential of significant 

changes in the existing flow regime due 

to such activities as hydropower 

generation, water diversion, or water 

withdrawal; the potential of significant 

alteration of water chemistry or water 

quality due to discharges or land use 

activities; and the potential of 

significant changes in stream bed 

material composition and quality by 

activities such as construction projects, 

livestock grazing, timber harvesting, and 

other watershed and floodplain 

disturbances that release sediments or 

nutrients into the water. 

Unit RH 2: Yellowleaf Creek, Shelby 

County, Alabama 

Unit 2 for the rough hornsnail 

includes approximately 6.4 km (4 mi) of 

the Yellowleaf Creek channel from the 

confluence of Morgan Creek, 

downstream to 1.6 km (1 mi) below the 

Alabama Highway 25 crossing in Shelby 

County, Alabama. The State of Alabama 

owns navigable stream bottoms within 

the ordinary high water line, and the 

lower reach of Yellowleaf Creek is 

considered navigable. 

The rough hornsnail has been found 

to occupy this entire reach (Powell in 

litt. 2009). This reach of Yellowleaf 

Creek is characterized by a stable 

channel, natural flows, and appropriate 

water quality and substrates (PCEs 1, 2, 

3, and 4). Threats to the rough hornsnail 

and its habitat in Yellowleaf Creek that 

may require special management of 

PCEs 1, 2, 3, and 4 include the potential 

of activities (such as channelization, 

impoundment, and channel excavation) 

that could cause aggradation or 

degradation of the channel bed 

elevation or significant bank erosion; 

the potential of significant changes in 

the existing flow regime due to such 

activities as water diversion or water 

withdrawal; the potential of significant 

alteration of water chemistry or water 

quality due to discharges or nonpoint 

source pollution; and the potential of 

significant changes in stream bed 

material composition and quality by 

activities such as construction projects, 

livestock grazing, timber harvesting, and 

other watershed and floodplain 

disturbances that release sediments or 

nutrients into the water. 

Effects of Critical Habitat Designation 

Section 7 Consultation 

Section 7(a)(2) 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 


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habitat. Decisions by the courts of 

appeals for the Fifth and Ninth Circuits 

have invalidated our definition of 

‘‘destruction or adverse modification’’ 

(50 CFR 402.02) (see Gifford Pinchot 

Task Force v. U.S. Fish and Wildlife 

Service, 378 F.3d 1059 (9th Cir. 2004) 

and Sierra Club v. U.S. Fish and 

Wildlife Service, 245 F.3d 434, 442 (5th 

Cir. 2001)), and we do not rely on this 

regulatory definition when analyzing 

whether an action is likely to destroy or 

adversely modify critical habitat. Under 

the provisions of the Act, we determine 

destruction or adverse modification on 

the basis of whether, with 

implementation of the proposed Federal 

action, the affected critical habitat 

would remain functional (or retain the 

current ability for the PCEs to be 

functionally established) to serve its 

intended conservation role for the 

species. 

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 the species or to 

destroy or adversely modify its critical 

habitat. Activities on State, tribal, local, 

or private lands requiring a Federal 

permit (such as a permit from the U.S. 

Army Corps of Engineers under section 

404 of the Clean Water Act (33 U.S.C. 

1251 et seq.) or a permit from the 

Service under section 10 of the Act) or 

involving some other Federal action 

(such as funding from the Federal 

Highway Administration, Federal 

Aviation Administration, or the Federal 

Emergency Management Agency) are 

subject to the section 7(a)(2) 

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(a)(2) 

consultations. 

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, 

we document compliance with the 

requirements of section 7(a)(2) through 

our issuance of: 

(1) A concurrence letter for Federal 

actions that may affect, but are not 

likely to adversely affect, listed species 

or critical habitat; or 

(2) A biological opinion for Federal 

actions that may affect, and are likely to 

adversely affect, listed species or critical 

habitat. 

When we issue a biological opinion 

concluding that a project is likely to 

jeopardize the continued existence of a 

listed species or destroy or adversely 

modify critical habitat, we also provide 

reasonable and prudent alternatives to 

the project, if any are identifiable. We 

define ‘‘reasonable and prudent 

alternatives’’ 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, 

• Can be implemented consistent 

with the scope of the Federal agency’s 

legal authority and jurisdiction, 

• Are economically and 

technologically feasible, and 

• Would, in the Director’s opinion, 

avoid jeopardizing the continued 

existence of the listed species or 

destroying or adversely modifying 

critical habitat. 

Reasonable and prudent alternatives 

can vary from slight project 

modifications to extensive redesign or 

relocation of the project. Costs 

associated with implementing a 

reasonable and prudent alternative are 

similarly variable. 

Regulations at 50 CFR 402.16 require 

Federal agencies to reinitiate 

consultation on previously reviewed 

actions in instances where we have 

listed a new species or subsequently 

designated critical habitat that may be 

affected and the Federal agency has 

retained discretionary involvement or 

control over the action (or the agency’s 

discretionary involvement or control is 

authorized by law). Consequently, 

Federal agencies may sometimes need to 

request reinitiation of consultation with 

us on actions for which formal 

consultation has been completed, if 

those actions with discretionary 

involvement or control may affect 

subsequently listed species or 

designated critical habitat. 

Application of the ‘‘Adverse 

Modification’’ Standard 

The key factor related to the adverse 

modification determination is whether, 

with implementation of the proposed 

Federal action, the affected critical 

habitat would continue to serve its 

intended conservation role for the 

species, or would retain its current 

ability for the PCEs to be functionally 

established. Activities that may destroy 

or adversely modify critical habitat are 

those that alter the PCEs to an extent 

that appreciably reduces the 

conservation value of critical habitat for 

each species (the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail). 

Section 4(b)(8) of the Act requires us 

to briefly evaluate and describe, in any 

proposed or final regulation that 

designates critical habitat, activities 

involving a Federal action that may 

destroy or adversely modify such 

habitat, or that may be affected by such 

designation. 

Activities that, when carried out, 

funded, or authorized by a Federal 

agency, may affect critical habitat and 

therefore should result in consultation 

for each species (Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail) include, but are not limited 

to: 

(1) Actions that would alter the 

geomorphology of stream and river 

habitats. Such activities could include, 

but are not limited to, instream 

excavation or dredging, impoundment, 

channelization, and discharge of fill 

materials. These activities could cause 

aggradation or degradation of the 

channel bed elevation or significant 

bank erosion and result in entrainment 

or burial of these mollusks, and could 

cause other direct or cumulative adverse 

effects to these species and their life 

cycles. 

(2) Actions that would significantly 

alter the existing flow regime. Such 

activities could include, but are not 

limited to, impoundment, water 

diversion, water withdrawal, and 

hydropower generation. These activities 

could eliminate or reduce the habitat 

necessary for growth and reproduction 

of these mollusks. 

(3) Actions that would significantly 

alter water chemistry or water quality 

(for example, temperature, pH, 

contaminants, and excess nutrients). 

Such activities could include, but are 

not limited to, hydropower discharges, 

or the release of chemicals, biological 

pollutants, or heated effluents into 

surface water or connected groundwater 

at a point source or by dispersed release 

(nonpoint source). These activities 

could alter water conditions that are 

beyond the tolerances of these mollusks 

and result in direct or cumulative 

adverse affects to the species and their 

life cycles. 

(4) Actions that would significantly 

alter stream bed material composition 

and quality by increasing sediment 

deposition or filamentous algal growth. 

Such activities could include, but are 

not limited to, construction projects, 

livestock grazing, timber harvest, offroad vehicle use, and other watershed 

and floodplain disturbances that release 

sediments or nutrients into the water. 

These activities could eliminate or 

reduce habitats necessary for the growth 

and reproduction of these mollusks by 

causing excessive sedimentation and 

burial of the species or their habitats, or 

nutrification leading to excessive 

filamentous algal growth. Excessive 


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filamentous algal growth can cause 

reduced nighttime dissolved oxygen 

levels through respiration, cover the 

hard substrates required by aquatic 

snails for egg deposition, and prevent 

mussel glochidia from settling into 

stream sediments. 

Exemptions and Exclusion 

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

The Sikes Act Improvement Act of 

1997 (Sikes Act) (16 U.S.C. 670a) 

required each military installation that 

includes land and water suitable for the 

conservation and management of 

natural resources to complete an 

integrated natural resources 

management plan (INRMP) by 

November 17, 2001. An INRMP 

integrates implementation of the 

military mission of the installation with 

stewardship of the natural resources 

found on the base. Among other things, 

each INRMP must, to the extent 

appropriate and applicable, provide for 

fish and wildlife management; fish and 

wildlife habitat enhancement or 

modification; wetland protection, 

enhancement, and restoration where 

necessary to support fish and wildlife; 

and enforcement of applicable natural 

resource laws. 

The National Defense Authorization 

Act for Fiscal Year 2004 (Pub. L. 108– 

136) amended the Act to limit areas 

eligible for designation as critical 

habitat. Specifically, section 4(a)(3)(B)(i) 

of the Act (16 U.S.C. 1533(a)(3)(B)(i)) 

now provides: ‘‘The Secretary shall not 

designate as critical habitat any lands or 

other geographical areas owned or 

controlled by the Department of 

Defense, or designated for its use, that 

are subject to an integrated natural 

resources management plan prepared 

under section 101 of the Sikes Act (16 

U.S.C. 670a), if the Secretary determines 

in writing that such plan provides a 

benefit to the species for which critical 

habitat is proposed for designation.’’ 

There are no Department of Defense 

lands with a completed INRMP within 

the critical habitat designation for any of 

the three species. Therefore, there are no 

specific lands that meet the criteria for 

being exempted from the designation of 

critical habitat under section 4(a)(3) of 

the Act. 

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

Section 4(b)(2) of the Act states that 

the Secretary must designate or revise 

critical habitat on the basis of the best 

available scientific data after taking into 

consideration the economic impact, 

national security impact, and any other 

relevant impact of specifying any 

particular area as critical habitat. The 

Secretary may exclude an area from 

critical habitat if he determines that the 

benefits of such exclusion outweigh the 

benefits of specifying such area as part 

of the critical habitat, unless he 

determines, based on the best scientific 

data available, that the failure to 

designate such area as critical habitat 

will result in the extinction of the 

species. In making that determination, 

the legislative history is clear that the 

Secretary has broad discretion regarding 

which factors to use and how much 

weight to give to any factor. 

Under section 4(b)(2) of the Act, we 

must consider the economic impact, 

national security impact, and any other 

relevant impact of specifying any 

particular area as critical habitat. For 

example, we consider whether there are 

lands owned or managed by the 

Department of Defense (DOD) where a 

national security impact might exist. We 

also consider whether landowners have 

developed any conservation plans for 

the area, or whether there are 

conservation partnerships that would be 

encouraged by designation of, or 

exclusion of lands from, critical habitat. 

In addition, we look at any tribal issues, 

and consider the government-togovernment relationship of the United 

States with tribal entities. We also 

consider the economic impacts, 

environmental impacts, and any social 

impacts that might occur because of the 

designation. 

Under section 4(b)(2) of the Act, in 

considering whether to exclude a 

particular area from the designation, we 

must identify the benefits of including 

the area in the designation, identify the 

benefits of excluding the area from the 

designation, and determine whether the 

benefits of exclusion outweigh the 

benefits of inclusion. If, based on this 

analysis, we determine that the benefits 

of exclusion outweigh the benefits of 

inclusion, we can exclude the area only 

if such exclusion would not result in the 

extinction of the species. 

In the proposed rule, we requested 

information on why any area should or 

should not be designated as critical 

habitat as provided by section 4 of the 

Act (16 U.S.C. 1531 et seq.), including 

whether the benefit of designation 

would outweigh threats to the species 

caused by designation such that the 

designation of critical habitat is 

prudent. In this instance, we have 

examined all comments submitted with 

respect to providing adequate protection 

and management for the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail. None of the comments 

provided sufficient information to 

satisfy the criteria necessary for 

exclusion from final critical habitat. 

In preparing this final rule, we 

determined that the lands within the 

designation of critical habitat for the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail are not owned or 

managed by the Department of Defense; 

there are currently no conservation 

partnerships for the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail; and the designation does not 

include any tribal lands or trust 

resources. Since the critical habitat 

designation includes only aquatic areas 

that are generally held in public trust, 

involves no Tribal lands, and includes 

no areas presently under special 

management or protection provided by 

a legally operative plan or agreement for 

the conservation of these mussels, we 

believe that, other than economics, there 

are no other relevant impacts to evaluate 

under section 4(b)(2). 

Economic Analysis (EA) 

We prepared an economic analysis 

that is consistent with the ruling of the 

United States Court of Appeals for the 

Tenth Circuit in New Mexico Cattle 

Growers Ass’n v. United States Fish and 

Wildlife Service, 248 F.3d 1277 (2001), 

and that was available for public review 

and comment during the comment 

period for the proposed rule. The final 

economic analysis is available on the 

Internet at http://www.regulations.gov. 

The final EA (Industrial Economics 

2009) considers the potential economic 

effects of actions relating to the 

conservation of the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail, including costs associated 

with sections 4, 7, and 10 of the Act, 

and including those attributable to 

designating critical habitat. It further 

considers the economic effects of 

protective measures taken as a result of 

other Federal, State, and local laws that 

aid habitat conservation for the Georgia 

pigtoe, interrupted rocksnail, and rough 

hornsnail in essential habitat areas. The 

EA considers both economic efficiency 

and distributional effects. In the case of 

habitat conservation, efficiency effects 

generally reflect the ‘‘opportunity costs’’ 

associated with the commitment of 

resources to comply with habitat 

protection measures (for example, lost 

economic opportunities associated with 

restrictions on land use). 

The final economic analysis states 

that costs associated with future 

conservation efforts that may benefit the 

three mollusks in critical habitat areas 

are estimated to be $8.97 million to 

$9.16 million annually, assuming a 7 

percent discount rate. Most (96 percent) 

of baseline costs quantified in this 

analysis are conservation efforts related 

to lost hydropower production value at 


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three facilities. The remaining 4 percent 

of potential future baseline costs are 

related to transportation activities, water 

quality management activities, and 

National Forest management activities. 

However, extensive actions are 

already currently planned within most 

of the critical habitat areas designated 

for these three species, on behalf of 11 

other listed mollusk species for which 

the areas have been previously 

designated as critical habitat (69 FR 

40083, July 1, 2004). Only 5 river miles 

(8 river kilometers) of this critical 

habitat designation do not overlap 

habitat for the 11 mussels, and no 

known projects are planned within, or 

which may affect, critical habitat in 

those areas. As such, incremental costs 

are anticipated to result entirely from 

the added administrative requirements 

of forecast section 7 consultations, and 

are estimated to be approximately 

$44,000 annually, assuming a 7 percent 

discount rate. 

Based on the best available 

information, including the prepared 

economic analysis, we believe that all of 

the eight units are essential for the 

conservation of these species. Critical 

habitat aids in the conservation of the 

species specifically by protecting the 

primary constituent elements on which 

the species depends. It can also result in 

benefits by providing information to the 

public, local and State governments, 

Federal agencies, and other entities 

engaged in activities or long-range 

planning in areas essential to the 

conservation of the species. 

Conservation of the interrupted 

rocksnail, rough hornsnail, and Georgia 

pigtoe and essential features of their 

habitats will require habitat 

management, protection, and 

restoration, which will be facilitated by 

knowledge of habitat locations and the 

physical and biological features of those 

habitats. We conclude that these 

benefits of inclusion outweigh the 

above-described costs of designation for 

all areas we are designating as critical 

habitat in this rule. 

Available Conservation Measures 

Conservation measures provided to 

species listed as endangered or 

threatened under the Act include 

recognition, recovery actions, 

requirements for Federal protection, and 

prohibitions against certain practices. 

Recognition through listing encourages 

and results in conservation actions by 

Federal, State, and private agencies; 

groups; and individuals. The Act 

provides for possible land acquisition 

and cooperation with the States and 

requires that recovery actions be carried 

out for all listed species. The protection 

required of Federal agencies and the 

prohibitions against taking and harm are 

discussed, in part, below. 

Section 7(a) of the Act, as amended, 

requires Federal agencies to evaluate 

their actions with respect to any species 

that is proposed or listed as endangered 

or threatened and with respect to its 

critical habitat, if any is being 

designated. Regulations implementing 

this interagency cooperation provision 

of the Act are codified at 50 CFR part 

402. Section 7(a)(2) 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 must enter 

into formal consultation with the 

Service. 

Federal activities that may affect the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail include, but are not 

limited to, the carrying out or the 

issuance of permits for reservoir 

construction, stream alterations, 

discharges, wastewater facility 

development, water withdrawal 

projects, pesticide registration, mining, 

and road and bridge construction. It has 

been the experience of the Service, 

however, that nearly all section 7 

consultations have been resolved so that 

the species have been protected and the 

project objectives have been met. 

Listing the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail initiates 

the development and implementation of 

rangewide recovery plans for each 

species. These plans will bring together 

Federal, State, and local agency efforts 

for the conservation of these species. 

Recovery plans will establish a 

framework for agencies to coordinate 

their recovery efforts. The plans will set 

recovery priorities and estimate the 

costs of the tasks necessary to 

accomplish the priorities. They also will 

describe the site-specific actions 

necessary to achieve conservation and 

survival of each species. 

Listing also will require us to review 

any actions on Federal lands and 

activities under Federal jurisdiction that 

may affect the three species; allow State 

plans to be developed under section 6 

of the Act; encourage scientific 

investigations of efforts to enhance the 

propagation or survival of the species 

under section 10(a)(1)(A) of the Act; and 

promote habitat conservation plans nonFederal lands and activities under 

section 10(a)(1)(B) of the Act. 

The Act and its implementing 

regulations found at 50 CFR 17.21 set 

forth a series of general prohibitions and 

exceptions that apply to all endangered 

wildlife. These prohibitions, in part, 

make it illegal for any person subject to 

the jurisdiction of the United States to 

take (includes harass, harm, pursue, 

hunt, shoot, wound, kill, trap, capture, 

or collect, or to attempt any of these), 

import or export, ship in interstate 

commerce in the course of commercial 

activity, or sell or offer for sale in 

interstate or foreign commerce any 

listed species. It also is illegal to 

possess, sell, deliver, carry, transport, or 

ship any wildlife that has been taken 

illegally. Certain exceptions apply to 

agents of the Service and State 

conservation agencies. 

Permits may be issued to carry out 

otherwise prohibited activities 

involving endangered wildlife species 

under certain circumstances. 

Regulations governing permits are set 

forth at 50 CFR 17.22 and 17.23. Such 

permits are available for scientific 

purposes, to enhance the propagation or 

survival of the species, and for 

incidental take in connection with 

otherwise lawful activities. 

Under the Interagency Cooperative 

Policy for Endangered Species Act 

Section 9 Prohibitions, published in the 

Federal Register on July 1, 1994 (59 FR 

34272), we identify to the maximum 

extent practicable those activities that 

would or would not constitute a 

violation of section 9 of the Act when 

the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail are 

listed. The intent of this policy is to 

increase public awareness as to the 

effects of these listings on future and 

ongoing activities within a species’ 

range. We believe, based on the best 

available information, that the following 

actions will not result in a violation of 

the provisions of section 9 of the Act, 

provided these actions are carried out in 

accordance with existing regulations 

and permit requirements: 

(1) Possession, delivery, or movement, 

including interstate transport that does 

not involve commercial activity, of 

specimens of these species that were 

legally acquired prior to the addition of 

these three mollusks to the Federal List 

of Endangered or Threatened Wildlife; 

(2) Discharges into waters supporting 

the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail, 

provided these activities are carried out 

in accordance with existing regulations 

and permit requirements (e.g., activities 

subject to section 404 of the Clean Water 

Act and discharges regulated under the 

National Pollutant Discharge 

Elimination System (NPDES)); 

(3) Agricultural and silvicultural 

activites or development and 

construction activities designed and 


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implemented under State and local 

water quality regulations and 

implemented using approved best 

management practices; and 

(4) Any actions that may affect the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail that are authorized, 

funded, or carried out by a Federal 

agency (such as bridge and highway 

construction, pipeline construction, 

hydropower licensing), when the action 

is conducted in accordance with the 

consultation requirements for listed 

species under section 7 of the Act. 

Potential activities that we believe 

will likely be considered a violation of 

section 9 of the Act, include, but are not 

limited to, the following: 

(1) Unauthorized possession, 

collecting, trapping, capturing, killing, 

harassing, sale, delivery, or movement, 

including interstate and foreign 

commerce, or harming, or attempting 

any of these actions, of the Georgia 

pigtoe, interrupted rocksnail, and rough 

hornsnail; 

(2) Unlawful destruction or alteration 

of their habitats (such as unpermitted 

instream dredging, impoundment, 

channelization, or discharge of fill 

material) that impairs essential 

behaviors, such as breeding, feeding, or 

sheltering, or results in killing or 

injuring any of these species; 

(3) Violation of any discharge or water 

withdrawal permit that results in harm 

or death to any of these species or that 

results in degradation of their occupied 

habitat to an extent that essential 

behaviors such as breeding, feeding, and 

sheltering are impaired; and 

(4) Unauthorized discharges or 

dumping of toxic chemicals or other 

pollutants into waters supporting the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail that kills or injures 

these species, or otherwise impairs 

essential life-sustaining requirements, 

such as reproduction, food, or shelter. 

Other activities not identified above 

will be reviewed on a case-by-case basis 

to determine if a violation of section 9 

of the Act may be likely to result from 

such activity. The Service does not 

consider these lists to be exhaustive and 

provides them as information to the 

public. 

If you have questions regarding 

whether specific activities will likely 

violate the provisions of section 9 of the 

Act, contact the Jackson, Ecological 

Services Field Office (see ADDRESSES). 

Requests for copies of regulations 

regarding listed species and inquiries 

about prohibitions and permits should 

be addressed to the U.S. Fish and 

Wildlife Service, Ecological Services 

Division, 1875 Century Boulevard, 

Atlanta, GA 30345 (phone 404–679– 

7313; fax 404–679–7081). 

Required Determinations 

Regulatory Planning and Review— 

Executive Order 12866 

The Office of Management and Budget 

(OMB) has determined that this rule is 

not significant under Executive Order 

12866 (E.O. 12866). OMB bases its 

determination upon the following four 

criteria: 

(a) Whether the rule will have an 

annual effect of $100 million or more on 

the economy or adversely affect an 

economic sector, productivity, jobs, the 

environment, or other units of the 

government. 

(b) Whether the rule will create 

inconsistencies with other Federal 

agencies’ actions. 

(c) Whether the rule will materially 

affect entitlements, grants, user fees, 

loan programs, or the rights and 

obligations of their recipients. 

(d) Whether the rule raises novel legal 

or policy issues. 

Regulatory Flexibility Act (5 U.S.C. 601 

et seq.) 

Under the Regulatory Flexibility Act 

(RFA; 5 U.S.C. 601 et seq.), as amended 

by the Small Business Regulatory 

Enforcement Fairness Act (SBREFA), 

whenever an agency must 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 effect of the rule on small 

entities (i.e., small businesses, small 

organizations, and small government 

jurisdictions). However, no regulatory 

flexibility analysis is required if the 

head of an agency certifies the rule will 

not have a significant economic impact 

on a substantial number of small 

entities. SBREFA amended RFA to 

require Federal agencies to provide a 

certification statement of factual basis 

for certifying that the rule will not have 

a significant economic impact on a 

substantial number of small entities. In 

this final rule, we are certifying that the 

critical habitat designation for the three 

mollusks will not have a significant 

economic impact on a substantial 

number of small entities. The following 

discussion explains our rationale. 

According to the Small Business 

Administration (SBA), small entities 

include small organizations, such as 

independent nonprofit organizations; 

small governmental jurisdictions, 

including school boards and city and 

town governments that serve fewer than 

50,000 residents; as well as small 

businesses. Small businesses include 

manufacturing and mining concerns 

with fewer than 500 employees, 

wholesale trade entities with fewer than 

100 employees, retail and service 

businesses with less than $5 million in 

annual sales, general and heavy 

construction businesses with less than 

$27.5 million in annual business, 

special trade contractors doing less than 

$11.5 million in annual business, and 

agricultural businesses with annual 

sales less than $750,000. To determine 

if potential economic impacts to these 

small entities are significant, we 

consider the types of activities that 

might trigger regulatory impacts under 

this rule, as well as the types of project 

modifications that may result. In 

general, the term ‘‘significant economic 

impact’’ is meant to apply to a typical 

small business firm’s business 

operations. 

To determine if the rule could 

significantly affect a substantial number 

of small entities, we consider the 

number of small entities affected within 

particular types of economic activities 

(e.g., housing development, grazing, oil 

and gas production, timber harvesting). 

We apply the ‘‘substantial number’’ test 

individually to each industry to 

determine if certification is appropriate. 

However, the SBREFA does not 

explicitly define ‘‘substantial number’’ 

or ‘‘significant economic impact.’’ 

Consequently, to assess whether a 

‘‘substantial number’’ of small entities is 

affected by this designation, this 

analysis considers the relative number 

of small entities likely to be impacted in 

an area. In some circumstances, 

especially with critical habitat 

designations of limited extent, we may 

aggregate across all industries and 

consider whether the total number of 

small entities affected is substantial. In 

estimating the number of small entities 

potentially affected, we also consider 

whether their activities have any 

Federal involvement. 

Designation of critical habitat only 

affects activities authorized, funded, or 

carried out by Federal agencies. Some 

kinds of activities are unlikely to have 

any Federal involvement and so will not 

be affected by critical habitat 

designation. In areas where the species 

are present, Federal agencies already are 

required to consult with us under 

section 7 of the Act on activities they 

authorize, fund, or carry out that may 

affect the three mollusks. Federal 

agencies also must consult with us if 

their activities may affect critical 

habitat. Designation of critical habitat, 

therefore, could result in an additional 

economic impact on small entities due 

to the requirement to reinitiate 

consultation for ongoing Federal 


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activities (see Application of the 

‘‘Adverse Modification’’ Standard 

section). 

In our final economic analysis of the 

proposed critical habitat designation, 

we evaluated the potential economic 

effects on small business entities 

resulting from conservation actions 

related to the listing of the three 

mollusks and the proposed designation 

of critical habitat. The analysis is based 

on the estimated impacts associated 

with the proposed rulemaking as 

described in Sections 2 through 6 and 

Appendix B of the analysis and 

evaluates the potential for economic 

impacts related to: (1) Water 

management; (2) water quality; and (3) 

other activities (dredging, general 

construction, bridge construction, and 

natural gas pipeline). 

According to the final economic 

analysis, impacts on small entities due 

to this rule are expected to be modest 

because the incremental costs of the rule 

are estimated to be administrative in 

nature. The only incremental impacts 

associated with this rulemaking are 

administrative costs of consultation 

under section 7 of the Act, which are 

expected to be approximately $44,000 

annually, using a 7 percent discount 

rate. The average of such costs to a small 

business over the next 20 years, 

discounted at 7 percent, is estimated to 

range from $0 to $18,300. The 

annualized incremental impacts, 

discounted at 7 percent, are expected to 

be distributed among specific activities 

as follows: 42 percent transportation/ 

construction, 33 percent water quality, 

18 percent National Forest activities, 

and 7 percent water management. 

In summary, we considered whether 

this designation will result in a 

significant economic effect on a 

substantial number of small entities. 

Based on the above reasoning and 

currently available information, we 

concluded that this rule will not result 

in a significant economic impact on a 

substantial number of small entities. 

Therefore, we are certifying that the 

designation of critical habitat for the 

three mollusks will not have a 

significant economic impact on a 

substantial number of small entities, 

and a regulatory flexibility analysis is 

not required. 

Energy Supply, Distribution, or Use— 

Executive Order 13211 

Pursuant to Executive Order No. 

13211, ‘‘Actions Concerning Regulations 

that Significantly Affect Energy Supply, 

Distribution, or Use,’’ issued May 18, 

2001, Federal agencies must prepare 

and submit a ‘‘Statement of Energy 

Effects’’ for all ‘‘significant energy 

actions.’’ The purpose of this 

requirement is to ensure that all Federal 

agencies ‘‘appropriately weigh and 

consider the effects of the Federal 

Government’s regulations on the supply, 

distribution, and use of energy.’’ 

The Office of Management and Budget 

(OMB) has provided guidance for 

implementing E.O. 13211 that outlines 

nine outcomes that may constitute ‘‘a 

significant adverse effect’’ when 

compared without the regulatory action 

under consideration. The economic 

analysis finds that incremental impacts 

of the designation of critical habitat are 

the subject of the analysis under 

Executive Order No. 13211. The 

potential effects of this designation on 

power production were considered in 

the economic analysis. The economic 

analysis finds that water managers at 

four hydroelectric production facilities 

in the ACT Basin are likely to undertake 

conservation efforts for listed species 

that will benefit the three mollusks, at 

an estimated cost of $8.8 million 

annually. Specifically, three facilities 

(Carters, Weiss, Jordan) are expected to 

modify operations to provide additional 

flows for the benefit of downstream 

aquatic species. However, these 

modifications related to conserving the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail are expected to 

occur absent these critical habitat 

designations, because the areas affected 

have been previously designated as 

critical habitat for, and are occupied by, 

other listed mollusk species with 

similar PCEs and habitat needs. 

Incremental impacts incurred from this 

critical habitat designation are all 

expected to be administrative in nature, 

and the designation of critical habitat 

for the Georgia pigtoe, interrupted 

rocksnail, and rough hornsnail is not 

expected to lead to any of the adverse 

outcomes specified in the OMB 

guidance. As such, this final designation 

of critical habitat is not expected to 

significantly affect energy supplies, 

distribution, or use, and a Statement of 

Energy Effects is not 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, 

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 

jeopardize the continued existence of 

the species, or 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 listing these 

species or designating critical habitat 

shift the costs of the large entitlement 

programs listed above on to State 

governments. 

(b) We have determined that the 

designation of critical habitat for the 

Georgia pigtoe, interrupted rocksnail, or 


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rough hornsnail will significantly or 

uniquely affect small governments 

because these mollusk species occur 

primarily in State-owned river channels, 

or in remote privately owned stream 

channels. As such, a Small Government 

Agency Plan is not required. 

Takings 

In accordance with Executive Order 

12630 (‘‘Government Actions and 

Interference with Constitutionally 

Protected Private Property Rights’’), we 

have analyzed the potential takings 

implications of designating critical 

habitat for the Georgia pigtoe, 

interrupted rocksnail, and rough 

hornsnail in a takings implications 

assessment. The takings implications 

assessment concludes that this 

designation of critical habitat for the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail does not pose 

significant takings implications. 

Federalism—Executive Order 13132 

In accordance with Executive Order 

13132 (Federalism), 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 critical habitat 

designation with, appropriate State 

resource agencies in Alabama, Georgia, 

and Tennessee. The critical habitat 

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 PCEs 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 

governments in long-range planning 

(rather than waiting for case-by-case 

section 7 consultations to occur). 

Where State and local governments 

require approval or authorization from a 

Federal agency for actions that may 

affect critical habitat, consultation 

under section 7(a)(2) of the Act would 

be required. While non-Federal entities 

that receive Federal funding, assistance, 

or permits, or that otherwise require 

approval or authorization from a Federal 

agency for an action, may be indirectly 

impacted by the designation of critical 

habitat, the legally binding duty to 

avoid destruction or adverse 

modification of critical habitat rests 

squarely on the Federal agency. 

Civil Justice Reform—Executive Order 

12988 

In accordance with Executive Order 

12988, 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 

designated critical habitat for the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail in accordance with 

the provisions of the Act. This final rule 

uses standard property descriptions and 

identifies the PCEs within the 

designated areas to assist the public in 

understanding the habitat needs of the 

Georgia pigtoe, interrupted rocksnail, 

and rough hornsnail. 

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 

(NEPA) (42 U.S.C. 4321 et seq.) 

We determined that environmental 

assessments and environmental impact 

statements, as defined under the 

authority of the National Environmental 

Policy Act of 1969, need not be 

prepared in connection with regulations 

adopted under section 4(a) of the Act. 

We published a notice outlining our 

reasons for this determination in the 

Federal Register on October 25, 1983 

(48 FR 49244). 

Also, it is our position that, outside 

the jurisdiction of the United States 

Court of Appeals for the Tenth Circuit, 

we do not need to prepare 

environmental analyses as defined by 

NEPA (42 U.S.C. 4321 et seq.) in 

connection with designating critical 

habitat under the Act. We published a 

notice outlining our reasons for this 

determination in the Federal Register 

on October 25, 1983 (48 FR 49244). This 

assertion was upheld by the Circuit 

Court of the United States for the Ninth 

Circuit (Douglas County v. Babbitt, 48 

F.3d 1495 (9th Cir. 1995), cert. denied 

516 U.S. 1042 (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, to 

work directly with tribes in developing 

programs for healthy ecosystems, to 

acknowledge that tribal lands are not 

subject to the same controls as Federal 

public lands, to remain sensitive to 

Indian culture, and to make information 

available to tribes. One parcel of land 

adjacent to Unit RH–1 is owned by the 

Poarch Creek Band of Indians, and the 

Creek Indian Enterprises, a small entity, 

runs a small casino on the site. We 

contacted the Poarch Creek Band 

regarding our proposed listing and 

critical habitat designation, and the 

draft economic analysis. As of the 

publication date of this rule, we have 

not received any concerns from, or been 

contacted by, the Poarch Creek Band 

regarding the designation of critical 

habitat adjacent to their lands. 

References Cited 

A complete list of all references cited 

in this rulemaking is available on the 

Internet at http://www.regulations.gov 

and upon request from the Field 

Supervisor, Jackson Ecological Services 

Field Office (see ADDRESSES section). 

Author(s) 

The primary author of this package is 

Paul Hartfield of the Jackson Ecological 

Services Field Office (see ADDRESSES). 

List of Subjects in 50 CFR Part 17 

Endangered and threatened species, 

Exports, Imports, Reporting and 

recordkeeping requirements, 

Transportation. 

Regulation Promulgation 

■ Accordingly, we 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. Amend § 17.11(h) as follows: 

■ a. Add ‘‘Pigtoe, Georgia’’ in 

alphabetical order under CLAMS; and 

■ b. Add ‘‘Hornsnail, rough’’ and 

‘‘Rocksnail, interrupted’’ in alphabetical 

order under SNAILS, to the List of 

Endangered and Threatened Wildlife to 

read as follows: 


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§ 17.11 Endangered and threatened 

wildlife. 

* * * * * 

(h) * * * 

Species 

Historic range 

Vertebrate 

population 

where endangered or 

threatened 

Status When listed Critical 

habitat 

Special 

rules Common name Scientific name 

* * * * * * * 

CLAMS

* * * * * * * 

Pigtoe, Georgia ............ Pleurobema 

hanleyianum.

U.S.A. (AL, GA, TN) ... NA E 777 17.95(f) NA 

* * * * * * * 

SNAILS

* * * * * * * 

Hornsnail, rough ........... Pleurocera foremani .... U.S.A. (AL) .................. NA E 777 17.95(f) NA 

* * * * * * * 

Rocksnail, interrupted .. Leptoxis foremani ........ U.S.A. (AL, GA) .......... NA E 777 17.95(f) NA 

* * * * * * * 

■ 3. Amend § 17.95(f) by adding entries 

for ‘‘Georgia pigtoe (Pleurobema 

hanleyianum)’’, ‘‘Interrupted Rocksnail 

(Leptoxis foremani)’’, and ‘‘Rough 

Hornsnail (Pleurocera foremani)’’ at the 

end of the paragraph to read as set forth 

below: 

§ 17.95 Critical habitat—fish and wildlife. 

* * * * * 

(f) Clams and Snails. 

* * * * * 

Georgia Pigtoe (Pleurobema 

hanleyianum) 

(1) Critical habitat units are depicted 

for Cherokee, Coosa, and Clay Counties, 

Alabama; Murray and Whitfield 

Counties, Georgia; and Bradley and Polk 

Counties, Tennessee, on the maps 

below. 

(2) The primary constituent elements 

(PCEs) of critical habitat for the Georgia 

pigtoe are the habitat components that 

provide: 

(i) Geomorphically stable stream and 

river channels and banks (channels that 

maintain lateral dimensions, 

longitudinal profiles, and sinuosity 

patterns over time without an aggrading 

or degrading bed elevation). 

(ii) A hydrologic flow regime (the 

magnitude, frequency, duration, and 

seasonality of discharge over time) 

necessary to maintain benthic habitats 

where the species is found. Unless other 

information becomes available, existing 

conditions at locations where the 

species occurs will be considered as 

minimal flow requirements for survival. 

(iii) Water quality (including 

temperature, pH, hardness, turbidity, 

oxygen content, and chemical 

constituents) that meets or exceeds the 

current aquatic life criteria established 

under the Clean Water Act (33 U.S.C. 

1251–1387). 

(iv) Sand, gravel, cobble, boulder, or 

bedrock substrates with low to moderate 

amounts of fine sediment and attached 

filamentous algae. 

(v) The presence of fish host(s) for the 

Georgia pigtoe (species currently 

unknown). Diverse assemblages of 

native fish will serve as a potential 

indication of presence of host fish. 

(3) Critical habitat does not include 

manmade structures existing on the 

effective date of this rule and not 

containing one or more of the PCEs, 

such as buildings, bridges, aqueducts, 

airports, and roads, and the land on 

which such structures are located. 

(4) Critical habitat unit maps. Maps 

were developed from USGS 7.5′ 

quadrangles. Critical habitat unit 

upstream and downstream limits were 

then identified by longitude and 

latitude using decimal degrees and 

converted to Universal Transverse 

Mercator (UTM) zone 16, coordinates. 

(5) Note: Index map of critical habitat 

units for the Georgia pigtoe follows: 


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BILLING CODE 4310–55–P 

(6) Unit 1 for Georgia pigtoe (GP 1): 

Conasauga River, Bradley and Polk 

Counties, Tennessee; Murray and 

Whitfield Counties, Georgia. 

(i) Unit GP 1 includes the channel of 

the Conasauga River from the 

confluence of Minnewaga Creek 

(710752.23E, 3875891.03N), Polk 

County, Tennessee, downstream to U.S. 

Highway 76 (694611.06E, 3851057.36N), 

Murray/Whitfield County, Georgia. 

(ii) Note: Map of Unit 1 (GP 1) for 

Georgia pigtoe (Conasauga River) 

follows: 


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(7) Unit 2 for Georgia pigtoe (GP 2), 

Terrapin Creek and Coosa River, 

Cherokee County, Alabama. 

(i) Unit GP 2 includes the channel of 

Terrapin Creek from Alabama Highway 

9 (628065.76E, 3770007.078N), 

downstream to the confluence with the 

Coosa River (621001.27E, 3777441.03N), 

Cherokee County, Alabama; and the 

Coosa River channel from Weiss Dam 

(614866.54E, 3781969.16N), 

downstream to a point 1.6 km (1 mi) 

below the confluence of Terrapin Creek 

(619751.69E, 3776654.79N), Cherokee 

County, Alabama. 

(ii) Note: Map of Unit 2 (GP 2) for 

Georgia pigtoe (Terrapin Creek, Coosa 

River) follows: 


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(8) Unit 3 for Georgia pigtoe (GP 3): 

Hatchet Creek, Coosa and Clay Counties, 

Alabama. 

(i) Unit GP 3 includes the channel of 

Hatchet Creek from Clay County Road 4 

(588215.16E, 3666038.46N), Clay 

County, downstream to the confluence 

of Swamp Creek at Coosa County Road 

29 (561904.90E, 3636065.37N), Coosa 

County, Alabama. 

(ii) Note: Map of Unit 3 (GP 3) for 

Georgia pigtoe (Hatchet Creek) follows: 


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Interrupted Rocksnail (Leptoxis 

foremani) 

(1) Critical habitat units are depicted 

for Cherokee and Elmore Counties, 

Alabama, and Gordon and Floyd 

Counties, Georgia, on the maps below. 

(2) The primary constituent elements 

(PCEs) of critical habitat for the 

interrupted rocksnail are the habitat 

components that provide: 

(i) Geomorphically stable stream and 

river channels and banks (channels that 

maintain lateral dimensions, 

longitudinal profiles, and sinuosity 

patterns over time without an aggrading 

or degrading bed elevation). 

(ii) A hydrologic flow regime (the 

magnitude, frequency, duration, and 

seasonality of discharge over time) 

necessary to maintain benthic habitats 

where the species is found. Unless other 

information becomes available, existing 

conditions at locations where the 

species occurs will be considered as 

minimal flow requirements for survival. 

(iii) Water quality (including 

temperature, pH, hardness, turbidity, 

oxygen content, and chemical 

constituents) that meets or exceeds the 

current aquatic life criteria established 

under the Clean Water Act (33 U.S.C. 

1251–1387). 

(iv) Sand, gravel, cobble, boulder, or 

bedrock substrates with low to moderate 

amounts of fine sediment and attached 

filamentous algae. 

(3) Critical habitat does not include 

manmade structures existing on the 

effective date of this rule and not 

containing one or more of the PCEs, 

such as buildings, bridges, aqueducts, 

airports, and roads, and the land on 

which such structures are located. 

(4) Critical habitat unit maps. Maps 

were developed from USGS 7.5′ 

quadrangles. Critical habitat unit 

upstream and downstream limits were 

then identified by longitude and 

latitude using decimal degrees and 

converted to Universal Transverse 

Mercator (UTM) zone 16, coordinates. 

(5) Note: Index map of critical habitat 

units for the interrupted rocksnail 

follows: 


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(6) Unit 1 for interrupted rocksnail 

(IR 1): Coosa River, Cherokee County, 

Alabama. 

(i) Unit IR 1 includes the Coosa River 

channel from Weiss Dam (614866.53E, 

3781969.15N), downstream to a point 

1.6 km (1 mi) below the confluence of 

Terrapin Creek (619751.694E, 

3776654.79N), Cherokee County, 

Alabama. 

(ii) Note: Map of Unit 1 (IR 1) for 

interrupted rocksnail (Coosa River) 

follows: 


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BILLING CODE 4310–55–C 

(7) Unit 2 for interrupted rocksnail 

(IR 2): Oostanaula River, Gordon and 

Floyd Counties, Georgia. 

(i) Unit IR 2 includes the primary 

channel of the Oostanaula River from 

the confluence of the Conasauga and 

Coosawattee Rivers (692275.90E, 

3824562.96N), Gordon County, 

downstream to Georgia Highway 1 Loop 

(668358.62E, 3792574.63N), Floyd 

County, Georgia. 

(ii) Note: Map of Unit 2 (IR 2) for 

interrupted rocksnail (Oostanaula River) 

follows: 


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BILLING CODE 4310–55–P 

(8) Unit 3 for interrupted rocksnail 

(IR 3): Lower Coosa River, Elmore 

County, Alabama. 

(i) Unit IR 3 includes the Coosa River 

channel from Jordan Dam (569930.28E, 

3609212.67N), downstream to Alabama 

Highway 111 Bridge (574324.83E, 

3600042.81N), Elmore County, 

Alabama. 

(ii) Note: Map of Unit 3 (IR 3) for 

interrupted rocksnail (Lower Coosa 

River) follows: 


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Federal Register / Vol. 75, No. 211 / Tuesday, November 2, 2010 / Rules and Regulations 67547 

Rough Hornsnail (Pleurocera foremani) 

(1) Critical habitat units are depicted 

for Elmore and Shelby Counties, 

Alabama, on the maps below. 

(2) The primary constituent elements 

(PCEs) of critical habitat for the rough 

hornsnail are the habitat components 

that provide: 

(i) Geomorphically stable stream and 

river channels and banks (channels that 

maintain lateral dimensions, 

longitudinal profiles, and sinuosity 

patterns over time without an aggrading 

or degrading bed elevation). 

(ii) A hydrologic flow regime (the 

magnitude, frequency, duration, and 

seasonality of discharge over time) 

necessary to maintain benthic habitats 

where the species is found. Unless other 

information becomes available, existing 

conditions at locations where the 

species occurs will be considered as 

minimal flow requirements for survival. 

(iii) Water quality (including 

temperature, pH, hardness, turbidity, 

oxygen content, and chemical 

constituents) that meets or exceeds the 

current aquatic life criteria established 

under the Clean Water Act (33 U.S.C. 

1251–1387). 

(iv) Sand, gravel, cobble, boulder, 

bedrock, or mud substrates with low to 

moderate amounts of fine sediment and 

attached filamentous algae. 

(3) Critical habitat does not include 

manmade structures existing on the 

effective date of this rule and not 

containing one or more of the primary 

constituent elements, such as buildings, 

bridges, aqueducts, airports, and roads, 

and the land on which such structures 

are located. 

(4) Critical habitat unit maps. Maps 

were developed from USGS 7.5′ 

quadrangles. Critical habitat unit 

upstream and downstream limits were 

then identified by longitude and 

latitude using decimal degrees and 

converted to Universal Transverse 

Mercator (UTM) zone 16, coordinates. 

(5) Note: Index map of critical habitat 

units for the rough hornsnail follows: 


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67548 Federal Register / Vol. 75, No. 211 / Tuesday, November 2, 2010 / Rules and Regulations 

(6) Unit 1 for rough hornsnail (RH 1): 

Lower Coosa River, Elmore County, 

Alabama. 

(i) Unit RH 1 includes the Coosa River 

channel from Jordan Dam (569930.28E, 

3609212.67N), downstream to the 

confluence of the Tallapoosa River 

(568995.14E, 3597805.93N), Elmore 

County, Alabama. 

(ii) Note: Map of Unit 1 (RH 1) for 

rough hornsnail (Coosa River) follows: 


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Federal Register / Vol. 75, No. 211 / Tuesday, November 2, 2010 / Rules and Regulations 67549 

(7) Unit 2 for rough hornsnail (RH 2): 

Yellowleaf Creek, Shelby County, 

Alabama. 

(i) Unit RH 2 includes the channel of 

Yellowleaf Creek from the confluence of 

Morgan Creek (550285.41E, 

3682865.13N), downstream to 1.6 km (1 

mi) below Alabama Highway 25 

(552296.38E, 3679287.87N), Shelby 

County, Alabama. 

(ii) Note: Map of Unit 2 (RH 2) for 

rough hornsnail (Yellowleaf Creek) 

follows: 


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67550 Federal Register / Vol. 75, No. 211 / Tuesday, November 2, 2010 / Rules and Regulations 

* * * * * Authority: The authority for this section is 

section 4 of the Endangered Species Act of 

1973, as amended (16 U.S.C. 1531 et seq.). 

Dated: October 15, 2010. 

Thomas L. Strickland, 

Assistant Secretary for Fish and Wildlife and 

Parks. 

[FR Doc. 2010–27417 Filed 11–1–10; 8:45 am] 

BILLING CODE 4310–55–C 


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