[Federal Register Volume 63, Number 50 (Monday, March 16, 1998)]
[Rules and Regulations]
[Pages 12664-12687]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-6493]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

RIN 1018-AC63


Endangered and Threatened Wildlife and Plants; Determination of 
Endangered Status for Five Freshwater Mussels and Threatened Status for 
Two Freshwater Mussels From the Eastern Gulf Slope Drainages of 
Alabama, Florida, and Georgia

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: The Fish and Wildlife Service (Service) determines five 
freshwater mussels, the fat threeridge (Amblema neislerii), shinyrayed 
pocketbook (Lampsilis subangulata), Gulf moccasinshell (Medionidus 
penicillatus), Ochlockonee moccasinshell (Medionidus simpsonianus), and 
oval pigtoe (Pleurobema pyriforme) to be endangered species, and two 
freshwater mussels, the Chipola slabshell (Elliptio chipolaensis) and 
purple bankclimber (Elliptoideus sloatianus) to be threatened species 
under the Endangered Species Act of 1973, as amended (Act). These 
mussels are endemic to eastern Gulf Slope streams draining the 
Apalachicolan Region of southeast Alabama, southwest Georgia, and north 
Florida. Their center of distribution is the Apalachicola-
Chattahoochee-Flint (ACF) River basin of southeast Alabama, southwest 
Georgia, and northwest Florida, and the Ochlockonee River system of 
southwest Georgia and northwest Florida. They are currently known from 
restricted portions of from one to four independent river systems. 
These species inhabit stable sandy and gravelly substrates in medium-
sized streams to large rivers, often in areas swept free of silt by the 
current. The abundance and distribution of the seven mussel species 
decreased historically from habitat loss associated with reservoir 
construction, channel construction and maintenance, and

[[Page 12665]]

erosion. These habitat changes have resulted in significant 
extirpations (localized loss of populations), restricted and fragmented 
distributions, and poor recruitment of young.

DATES: Effective: April 15, 1998.

ADDRESSES: The complete administrative file for this rule is available 
for inspection, by appointment, during normal business hours at the 
U.S. Fish and Wildlife Service, Jacksonville Field Office, 6620 
Southpoint Drive South, Suite 310, Jacksonville, Florida 32216.

FOR FURTHER INFORMATION CONTACT: Dr. Michael M. Bentzien at the above 
address, or 904/232-2580, ext. 106.

SUPPLEMENTARY INFORMATION:

Background

Introduction

    The fat threeridge, shinyrayed pocketbook, Gulf moccasinshell, 
Ochlockonee moccasinshell, oval pigtoe, Chipola slabshell, and purple 
bankclimber are freshwater mussels of the family Unionidae found only 
in eastern Gulf Slope streams draining the Apalachicolan Region, 
defined as streams from the Escambia to the Suwannee river systems, and 
occurring in southeast Alabama, southwest Georgia, and north Florida 
(Butler 1989). The Apalachicolan Region is known for its high level of 
endemicity, harboring approximately 30 species of endemic (found only 
in the region) mussels (Butler 1989). The Region drains primarily the 
Coastal Plain Physiographic Province. Only the headwaters of the Flint 
and Chattahoochee rivers, in the Apalachicola-Chattahoochee-Flint (ACF) 
River system, occur above the Fall Line in the Piedmont Physiographic 
Province in west-central Georgia.
    The decline of some of the species included in this rule was 
evident decades ago. The fat threeridge, oval pigtoe, Chipola 
slabshell, and purple bankclimber were considered rare, but locally 
abundant, in the 1950's (Clench and Turner 1956). The Gulf 
moccasinshell, oval pigtoe, and purple bankclimber were recognized in a 
list of rare species in 1970 (Athearn 1970), and the fat threeridge was 
added to the list of regionally rare mussels a year later (Stansbery 
1971a).

General Biology

    Freshwater mussel adults are filter-feeders, positioning themselves 
in substrates to facilitate siphoning of the water column for oxygen 
and food (Kraemer 1979). Their food includes primarily detritus, 
plankton, and other microorganisms (Fuller 1974).
    As a group, freshwater mussels are extremely long-lived, with life 
spans of up to 130 years for certain species (Neves and Moyer 1988, 
Bauer 1992). Life spans of these seven species are unknown. Based on 
the longevity of a congener of the fat threeridge (the threeridge 
[Amblema plicata]; Stansbery 1971b), the longevity of thick-shelled 
species (Stansbery 1961), and the large size attained by the fat 
threeridge and purple bankclimber (see ``Species Accounts'' in this 
section), the latter two species probably have long lifespans.
    Freshwater mussels generally have separate sexes. The age of sexual 
maturity is variable (Gordon and Layzer 1989), usually requiring from 
three (Zale and Neves 1982) to nine (Smith 1979) years, and may be sex 
dependent (Smith 1979). Males expel sperm into the water column, while 
females draw in the sperm with the in-current water flow (Gordon and 
Layzer 1989). Spawning appears to be temperature dependent (Zale and 
Neves 1982, Bruenderman and Neves 1993), but may also be influenced by 
stream flow (Hove and Neves 1994). Fertilization rates are dependent on 
spatial aggregation of reproductive adults (Downing et al. 1993). 
Fertilization takes place inside the shell; the fertilized eggs develop 
into larvae called glochidia. After an incubation period, mature 
glochidia are expelled into the water column and must come into contact 
with specific species of fish whose gills and fins they temporarily 
parasitize (Gordon and Layzer 1989).
    The shinyrayed pocketbook utilizes largemouth bass (Micropterus 
salmoides) and spotted bass (M. punctulatus) as primary host fishes. 
The latter species appears to have been introduced into the ACF River 
system (Lee et al. 1980). The Gulf moccasinshell utilizes the brown 
darter (Etheostoma edwini) and blackbanded darter (E. nigrofasciata); 
the sailfin shiner (Pteronotropis hypselopterus) serves as the host 
fish for the oval pigtoe (O'Brien 1996). Glochidia for the purple 
bankclimber transformed on mosquitofish (Gambusia holbrooki) and 
blackbanded darter, but these species were not considered by O'Brien 
(1996) to be the primary hosts for this mussel.
    Host fishes for the fat threeridge, Ochlockonee moccasinshell, and 
Chipola slabshell are unknown. The lampsiline Ochlockonee moccasinshell 
probably uses darters as host fish, as does its congeners, the Alabama 
moccasinshell (Medionidus acutissimus) (W.R. Haag, U.S. Forest Service, 
pers. comm.), Cumberland moccasinshell (M. conradicus) (Zale and Neves 
1982), and Gulf moccasinshell (O'Brien 1996). Several host fish 
families have been identified for the threeridge, a congener of the fat 
threeridge, and include eight species of centrarchids (the sunfish 
family) (Fuller 1974, Hoggarth 1992). Centrarchids have also been 
determined to be fish hosts for species of Elliptio (Fuller 1974, 
Hoggarth 1992), and may also serve as host for the Chipola slabshell 
and possibly the purple bankclimber, which, genetically, is very 
similar to Elliptio spp. (M. Mulvey, Savannah River Ecology Laboratory, 
pers. comm.). Minnows (Cyprinidae) may serve as hosts for the fat 
threeridge and Chipola slabshell.
    The complex life cycle of mussels increases the probability that 
weak links in their life history will preclude successful reproduction 
and recruitment (Neves 1993). Egg formation and fertilization are 
critical phases in the life history; mussels may fail to form eggs 
(Downing et al. 1989), or have incomplete fertilization (Matteson 
1948). Fertilization success has been shown to be strongly correlated 
with spatial aggregation, which either influences the rate of egg 
formation, improves fertilization rates of individuals, or both 
(Downing et al. 1993).

Status Survey

    These seven mussels were considered to be potential candidates for 
listing in 1989 (see Previous Federal Actions section). The Service 
requested its former National Fisheries Research Center (now the 
Florida-Caribbean Science Center of Biological Resources Division of 
the U.S. Geological Survey (USGS), subsequently referred to as 
``Center'') in Gainesville, Florida, to survey these species in 1991. 
The Center surveyed for mussels in both the ACF (324 sites) and 
Ochlockonee (77 sites) river systems from 1991 to 1993. Information 
gathered during the status survey was summarized by Butler (1993). 
Three criteria were used to select status survey sampling sites--(1) to 
obtain a thorough and even coverage of the basins, (2) to survey sites 
where, based on suitable habitat, there was a maximum chance of finding 
one or more of the target species; and (3) to resurvey as many of the 
historical sites as possible. The survey was designed to estimate 
species distributions and population status, not to determine all 
existing populations.
    Numerous sites were surveyed in every major river in these 
watersheds. Every major tributary was also sampled, and generally at 
least one sample was taken on other sizable tributaries in these river 
systems. A total of 183

[[Page 12666]]

mainstem, 189 tributary, and 39 reservoir sites were sampled in the ACF 
and Ochlockonee River systems. Additional sites were collected in the 
Santa Fe River system (Suwannee River system; three sites) and in 
Econfina Creek (Bay County, Florida; six sites). Highway bridge 
crossings and boat ramps were often used to provide direct access to 
sampling sites and to sections of river to be sampled by boat.
    The survey technique generally used was hand-picking or grubbing, 
which involves a methodical search of the substrate for siphons or 
partially exposed specimens, trails, or other signs. Low-visibility 
conditions require crawling or lying down on the bottom, and feeling 
for shells by running fingers through the substrate. SCUBA and/or 
snorkeling were used at about two-thirds of the study sites, 
supplemented by hand-picking in shallow water at most sites. Over 95 
percent of the collection sites were sampled by four or more people, 
spending an average of two hours total effort per sampling site. All 
habitat types at each site were sampled for mussels, but efforts 
focused on habitats likely to support the target species.
    The Center surveyed 150 to 250 meters (m) (492 to 820 feet (ft)) of 
a stream reach at most sites. A primary goal was to collect at each 
site until there was a high probability that all species occurring 
there were found. Small streams were surveyed from bank to bank and 
were sampled for longer linear distances than large rivers. Shoals with 
high habitat complexity were surveyed more intensively and over longer 
distances than slackwater sites with little variation in substrate. 
Sites where mussels were uncommon or where only a few common species 
were present were sampled for a shorter time and distance. Information 
important for establishing baseline mussel population status at each 
site was recorded either in the field or during laboratory analyses, 
including stream characteristics (e.g., width, depth, water clarity, 
substrate), species present, number of live and dead specimens per 
species, length of each live mussel, reproductive condition of female 
specimens, and condition of dead shells. Most of these specimens were 
retained for voucher material, and temporarily stored at the Center in 
Gainesville, Florida. After studies unrelated to the status survey are 
conducted, the material will be donated to the mollusk collection of an 
appropriate museum for curation.
    Over 2,300 historical records for mussels in the ACF and 
Ochlockonee River systems were also gathered from eight United States 
museums with significant mussel holdings. For the purposes of the 
survey, a historical collection was any collection made prior to the 
status survey (before 1991). Of 300 known historical sites for all 
mussel species from the ACF and Ochlockonee River systems, 250 are 
identifiable to a specific locality, and 108 harbored one or more of 
the seven species. Of the 108 sites with at least one of the species, 
100 were in the ACF River system and eight in the Ochlockonee River 
system. The ACF River system historical sites include the following--
Flint River system--39 sites, Chipola River system--31 sites, 
Chattahoochee River system--20 sites, and Apalachicola River system--10 
sites. Additional information on historical mussel populations was 
gathered from the scientific literature, unpublished technical reports, 
and field records and notes of various collectors.
    Previously unknown sites of occurrence for most of the species were 
discovered during the status survey in the ACF and Ochlockonee River 
systems. The Service believes that historic populations of these 
mussels occupied most or all available habitat, and that habitat for 
all seven species has declined. The newly discovered sites, therefore, 
represent previously unsampled sites. This accounts for the purple 
bankclimber being located at more sites during the status survey than 
it was known from historically (see ``Species Accounts'' below in this 
section). Since mussels are long-lived, these recently discovered 
populations have probably existed for at least the past century, as 
only a few generations would have elapsed from that time until the 
present.

Species Accounts

Fat Threeridge--Amblema Neisleri (Lea, 1858)
    The fat threeridge is a medium-sized to large, subquadrate, 
inflated, solid, and heavy shelled mussel that reaches a length of 102 
millimeters (mm) (4.0 inches (in)). Older, larger individuals are so 
inflated that their width approximates their height. The umbos are in 
the anterior quarter of the shell. The dark brown to black shell is 
strongly sculptured with seven to eight prominent horizontal parallel 
ridges. Internally, there are two subequal pseudocardinal teeth in the 
left valve and typically one large and one small tooth in the right 
valve. The nacre is bluish white to light purplish and very iridescent. 
The Service considers Unio neislerii Lea, 1858 to be a synonym of 
Amblema neislerii. This taxon was incorrectly assigned to the genera 
Quadrula and Crenodonta by Simpson (1914) and Clench and Turner (1956), 
respectively. Subsequent investigators (e.g., Turgeon et al. 1988) have 
correctly placed the fat threeridge in the genus Amblema.
    The fat threeridge was described from the Flint River, Macon 
County, Georgia. This species, endemic to the ACF River system, 
historically occurred in the mainstems of the Flint, Apalachicola, and 
lower Chipola rivers (Clench and Turner 1956, Butler 1993). Clench and 
Turner (1956) indicated that this species was generally rare, but 
locally abundant. In the Chipola River system, van der Schalie (1940) 
reported 17 specimens from two sites (average of 8.5 per site). Clench 
and Turner (1956) documented ten to 15 mussels per m (0.9 to 1.4 
mussels per ft) square over a 200 m (656 ft) stretch of Dead Lake 
(Chipola River) shoreline.
    For the status survey, 86 sites were sampled within the historical 
range of the fat threeridge, including eight of the 12 (67 percent) 
known historical sites. The fat threeridge was found at six of the 86 
(7 percent) sampled sites, three each on the Apalachicola and lower 
Chipola rivers. Only one of the eight (13 percent) historical sites 
still had live individuals. An average of 6.4 live individuals were 
found per site.
    No live fat threeridge mussels have been found since 1981 in the 
Flint River; the species is apparently extirpated from Georgia. 
Apparently common in Dead Lake in 1967 (H.G. Lee, amateur malacologist, 
pers. comm.), this species was not found live there in 1974 (W.H. 
McCullagh, amateur malacologist, pers. comm.), nor during the status 
survey.
    The smallest live fat threeridge found during the survey was 43 mm 
(1.7 in) long. Richardson and Yokley (1996) found evidence of juvenile 
fat threeridge at a site in the lower Apalachicola River thought to 
have the best extant population of this species (J. Brim Box, USGS, 
pers. comm.), where it was the second most common mussel species 
encountered. Three fat threeridges under 50 mm (2.0 in) in length were 
found employing total substratum removal from six 0.25 m (2.7 ft) 
square quadrats. Richardson and Yokley (1996) stated that the smallest 
specimens had fewer than the five presumed annual growth rings that 
might be indicative of juveniles. A fresh dead individual measured 24 
mm (0.9 in) in length and had two to three growth rings. In 1996, three 
live specimens ranging from 40 to 50 mm (1.6 to 2.0 in) in length were 
located in the same bed (C.A. O'Brien, USGS, pers. comm.). These data

[[Page 12667]]

indicate that the fat threeridge is experiencing limited recruitment at 
the site representing its best known population.
Shinyrayed Pocketbook--Lampsilis Subangulata (Lea, 1840)
    The shinyrayed pocketbook is a medium-sized species that reaches 
approximately 85 mm (3.3 in) in length. The shell is subelliptical, 
with broad, somewhat inflated umbos and a rounded posterior ridge. The 
shell is fairly thin but solid. The surface is smooth and shiny, light 
yellowish brown with fairly wide, bright emerald green rays over the 
entire length of the shell. Older individuals may appear much darker 
brown with obscure raying. Female specimens are more inflated 
postbasally, whereas males appear to be more pointed posteriorly. 
Internally, the pseudocardinal teeth are double and fairly large and 
erect in the left valve, and one large tooth and one spatulate tooth in 
the right valve. The nacre is white, with some individuals exhibiting a 
salmon tint in the vicinity of the umbonal cavity. The Service 
recognizes Unio subangulatus Lea, 1840 and Unio kirklandianus Wright, 
1897 as synonyms of Lampsilis subangulata.
    The shinyrayed pocketbook was described from the Chattahoochee 
River, Columbus, Georgia. Historically, this mussel occurred in 
mainstems and tributaries throughout the ACF River system, and in 
larger streams of the Ochlockonee River system (Clench and Turner 1956, 
Butler 1993). Van der Schalie (1940) found this species to be generally 
rare, but locally abundant, documenting 94 specimens at eight Chipola 
River system sites (average of 11.8 per site).
    During the status survey, 380 sites within the historical range of 
the shinyrayed pocketbook were sampled, including 28 of 54 (52 percent) 
known historical sites. Live individuals were found at 23 of the sample 
sites, including one site in a Chattahoochee River tributary in 
Alabama, 13 sites (12 on tributaries) in the Flint River system, one 
locality in the Chipola River, and eight sites (seven mainstem) in the 
upper half of the Ochlockonee River system. An average of 2.9 live 
individuals were found per site. Live individuals were located at six 
(21 percent) of the historical sites. This species has apparently been 
eliminated from all but one site in the Chattahoochee River system in 
Alabama, and from much of the Chipola River system.
    During unrelated studies subsequent to the completion of the status 
survey, ten additional sites for the shinyrayed pocketbook were located 
in the ACF River system. Eight of these new occurrences were from five 
Flint River tributaries; one each occurred in tributaries of the 
Chattahoochee and Chipola rivers (Butler and Brim Box 1995, J. Brim 
Box, USGS, pers. comm.). The latter two records represent streams where 
the species had not been previously collected. The Flint River system 
records include one stream where the species had never been collected 
(a small tributary of a stream where live specimens were found during 
the status survey), and another stream where it was found during the 
status survey as a single dead shell; the remaining sites are in 
tributaries where it was found live during the status survey.
    The smallest shinyrayed pocketbook specimen recorded during the 
status survey in the Ochlockonee River system, possibly an older 
juvenile, measured 41 mm (1.6 in) in length. In the ACF River system, 
the three smallest specimens, measuring 55 to 57 mm (2.17 to 2.24 in) 
in length, were gravid females. In 1995, four live, apparently 
juvenile, specimens from 30 to 40 mm (1.2 to 1.6 in) in length were 
located in a Flint River tributary (C.A. O'Brien, USGS, pers. comm.). 
O'Brien (1996) sampled the largest known bed of this species for 
juveniles. An 18 m (59.1 ft) by 8 m (26.2 ft) area had 37 adult 
shinyrayed pocketbooks (average of 2.1 per m square). Whole substratum 
removal of 54 0.25 m (2.7 ft) square quadrats within this bed yielded 
no juveniles of this species. The density of shinyrayed pocketbooks at 
the four other sites, where quantitative work conducted subsequent to 
the status survey yielded specimens, never exceeded 0.08 specimens per 
meter square (J. Brim Box, USGS, pers. comm.).
Gulf Moccasinshell--Medionidus Penicillatus (Lea, 1857)
    The Gulf moccasinshell is a small mussel that reaches a length of 
about 55 mm (2.2 in), is elongate-elliptical or rhomboidal and fairly 
inflated, and has relatively thin valves. The ventral margin is nearly 
straight or slightly rounded. The posterior ridge is rounded to 
slightly angled and intersects the end of the shell at the base line. 
Females tend to have the posterior point above the ventral margin and 
are somewhat more inflated. Sculpturing consists of a series of thin, 
radially-oriented plications along the length of the posterior slope. 
The remainder of the surface is smooth and yellowish to greenish brown 
with fine, typically interrupted green rays. The left valve has two 
stubby pseudocardinal and two arcuate lateral teeth. The right valve 
has one pseudocardinal and one lateral tooth. Nacre color is smokey 
purple or greenish and slightly iridescent at the posterior end. The 
Service recognizes Unio penicillatus Lea, 1857 and Unio kingi Wright, 
1900 as synonyms of Medionidus penicillatus.
    The recent taxonomic history of Medionidus species in the 
Apalachicolan Region is complex. In the Chipola River system, van der 
Schalie (1940) recorded two species of Medionidus--M. kingi and M. 
penicillatus. Clench and Turner (1956) synonymized M. kingi and two 
other nominal species, the Ochlockonee moccasinshell and Suwannee 
moccasinshell (M. walkeri [Wright, 1897]) under the Gulf moccasinshell, 
an arrangement also followed by Burch (1975). Johnson (1970) 
erroneously reported both the Gulf moccasinshell and Suwannee 
moccasinshell from the ACF River system and the Suwannee moccasinshell 
from the Ochlockonee and Suwannee rivers as well. Johnson (1977) 
recognized the validity of the Gulf moccasinshell, Ochlockonee 
moccasinshell, and Suwannee moccasinshell from Apalachicolan Region 
streams based on shell characters. The validity of the three 
allopatrically distributed Apalachicolan Region Medionidus species is 
also recognized by Turgeon et al. (1988).
    The Gulf moccasinshell was described from three sites in the ACF 
River system in Georgia--the Chattahoochee River near Columbus and near 
Atlanta, and the Flint River near Albany. The historical ACF River 
system distribution included tributaries and mainstems of the Flint, 
Chattahoochee, and Chipola rivers, and the mainstem Apalachicola River. 
More western localities in the Apalachicolan Region included Econfina 
Creek (Bay County, northwest Florida), the Choctawhatchee River system, 
and the Yellow River (Johnson 1977; Butler 1989, 1993). Clench and 
Turner (1956) considered this species rare, but locally abundant. Van 
der Schalie (1940) reported 166 specimens from 11 sites, including 130 
from two sites in the Chipola River system, an average of 15.1 per 
site.
    During the status survey, 330 sites within the historic range of 
the Gulf moccasinshell were sampled, including 13 of 31 (42 percent) 
known historical sites. This species was found at eight sites (two 
percent), including only one of the historical sites. It was found at 
seven sites (including one mainstem site) in the middle Flint River 
system, and at one Econfina Creek site. An average of 1.4 live 
individuals was

[[Page 12668]]

found per site. All Alabama populations of the Gulf moccasinshell 
appear to be extirpated, and no specimens were found in the Chipola 
River system during the status survey. The species has not been 
collected in the Choctawhatchee River system since the early 1930's and 
in the Yellow River since 1963 (Williams and Butler 1994).
    Six new sites for the Gulf moccasinshell from tributaries of the 
ACF River system were found subsequent to the status survey (Butler and 
Brim Box 1995, J. Brim Box, USGS, pers. comm.). Three sites were 
streams from which this species had never been found (one tributary 
each in the Chattahoochee, Flint, and Chipola rivers), two were streams 
(both Flint River system) where this species was found live during the 
status survey, and one site was a stream in the Chattahochee River 
system where a single dead shell had been located during the status 
survey.
    Densities of Gulf moccasinshells at two sites where quantitative 
work was conducted were under 0.4 specimens per meter square (J. Brim 
Box, USGS, pers. comm.). All specimens located during and subsequent to 
the status survey were adults; no specimens less than 50 mm (2.2 in) 
were located.
Ochlockonee Moccasinshell--Medionidus Simpsonianus Walker, 1905
    The Ochlockonee moccasinshell is a small species, generally under 
55 mm (2.2 in) in length. It is slightly elongate-elliptical in 
outline, the posterior end obtusely rounded at the shell's median line 
and the ventral margin broadly curved. The posterior ridge is 
moderately angular and covered in its entire length with well 
developed, irregular ridges. Sculpture may also extend onto the disk 
below the ridge. Surface texture is smooth. The color is light brown to 
yellowish green, with dark green rays formed by a series of connected 
chevrons or undulating lines across the length of the shell. Internal 
characters include thin straight lateral teeth and compressed 
pseudocardinal teeth. There are two laterals and two pseudocardinals in 
the left valve and one lateral and one pseudocardinal in the right 
valve. The nacre is bluish white. A summary of the taxonomic history of 
the genus Medionidus follows the Gulf moccasinshell description above.
    The Ochlockonee moccasinshell was described from the Ochlockonee 
River, Calvary, Grady County, Georgia. This Ochlockonee River system 
endemic was known historically from the mainstem and the Little River 
(Johnson 1977, Butler 1993). Museum records for this species sometimes 
numbered in the dozens of individuals at sites above Talquin Reservoir.
    During the status survey, eight sites were sampled within the 
historic range of the Ochlockonee moccasinshell, including three of six 
(50 percent) known historical sites. Live individuals were found at two 
sites (one specimen at each site); one of these was a historic site. 
Another specimen was located in 1995 (J. Brim Box, USGS, pers. comm.) 
at a site previously sampled during the status survey. Only three live 
individuals are known to have been collected since 1974 despite 
concerted efforts by numerous investigators; none were juveniles.
Oval Pigtoe--Pleurobema Pyriforme (Lea, 1857)
    The oval pigtoe is a small to medium-sized species that attains a 
length of about 60 mm (2.4 in). The shell is suboviform compressed, 
with a shiny smooth epidermis. The periostracum is yellowish, chestnut, 
or dark brown, rayless, and with distinct growth lines. The posterior 
slope is biangulate and forms a blunt point on the posterior margin. 
The umbos are slightly elevated above the hingeline. As is typical of 
the genus, no sexual dimorphism is displayed in shell characters. 
Internally, the pseudocardinal teeth are fairly large, crenulate, and 
double in both valves. The lateral teeth are somewhat shortened, 
arcuate, and double in each valve. Nacre color varies from salmon to 
bluish white and is iridescent posteriorly. Variation in this species 
has led to the description of various nominal species. The Service 
currently recognizes Unio pyriformis Lea, 1857, Unio modicus Lea, 1857, 
Unio bulbosus Lea, 1857, Unio amabilis Lea, 1865, Unio reclusum Wright, 
1898, Unio harperi Wright, 1899, and Pleurobema simpsoni Vanatta, 1915 
as synonyms of Pleurobema pyriforme.
    The oval pigtoe was described from the Chattahoochee River, near 
Columbus, Georgia. Historically, this species was one of the most 
widely distributed and common mussels endemic to the Apalachicolan 
Region. It occurred throughout the mainstems and several tributaries of 
both the Flint and Chipola River systems, in the lower Chattahoochee 
River mainstem and several of its tributaries, in the Apalachicola 
River mainstem, and in the upper portion of the Ochlockonee River 
system. The oval pigtoe was also known from a single Suwannee River 
mainstem site and the confluent Santa Fe River system, and in Econfina 
Creek (Clench and Turner 1956, Butler 1993). Once a species of 
localized abundance (Clench and Turner 1956), oval pigtoe populations 
sometimes numbered in the hundreds (van der Schalie 1940). In the 
Chipola River system, van der Schalie (1940) reported 470 specimens 
from 9 sites (an average of 52.2 per site).
    During the status survey, 410 sites were sampled within the 
historic range of this species, including 20 of 50 (40 percent) known 
historical sites. The oval pigtoe was found at 24 (6 percent) of the 
sample sites, including seven of the historic sites, with an average of 
5.2 live individuals per site. The species was found at one mainstem 
site and seven tributary sites in the Flint River system, six mainstem 
Chipola River sites, six mainstem sites and one tributary site in the 
upper Ochlockonee River system, one site in the New River (upper Santa 
Fe River system), and two sites in Econfina Creek. The oval pigtoe has 
apparently been extirpated from the Chattahoochee River system in 
Alabama and much of the Chipola River system.
    Subsequently, five new occurrences of the oval pigtoe were located 
in three ACF River system tributaries. One occurrence was from a stream 
in the Chipola River system not previously known to have harbored this 
species. The other four occurrences were in two streams (two sites in 
each stream), that are tributaries to the Chattahoochee and Flint 
rivers where the species had been recorded during the status survey 
(Butler and Brim Box 1995; J. Brim Box, USGS, pers. comm.).
    Oval pigtoe density at the five new sites never exceeded 0.4 
specimens per meter square (J. Brim Box, USGS, pers. comm.). The 
smallest individual collected during or subsequent to the status survey 
was 26 mm (1.0 in) in length, indicating that juveniles were not 
present in these collections.
Chipola Slabshell--Elliptio Chipolaensis Walker, 1905
    The Chipola slabshell is a medium-sized species reaching a length 
of about 85 mm (3.3 in). The shell is ovate to subelliptical, somewhat 
inflated and with the posterior ridge starting out rounded, but 
flattening to form a prominent biangulate margin. The surface is smooth 
and chestnut colored. Dark brown coloration may appear in the umbonal 
region and the remaining surface may exhibit alternating light and dark 
bands. The umbos are prominent, well above the hingeline. Internally, 
the umbonal cavity is rather deep. The lateral teeth are long, slender, 
and slightly curved; two in the left and one in the right valve. The 
pseudocardinal teeth are compressed and crenulate; two in the left and 
one in the right valve. Nacre color is salmon, becoming more

[[Page 12669]]

intense dorsally and somewhat iridescent posteriorly.
    The Chipola slabshell was described from the Chipola River, 
Florida. Clench and Turner (1956) restricted the type locality to the 
Chipola River, 1.6 km (1.0 mi) north of Marianna, Jackson County, 
Florida. This species was considered to be a Chipola River system 
endemic, occurring in the mainstem from the vicinity of Dead Lake 
upstream and in a few of its larger tributaries, all in Florida (van 
der Schalie 1940, Clench and Turner 1956). However, a historical record 
recently brought to light has been verified from a small tributary of 
the Chattahoochee River in extreme southeast Alabama (Butler 1993). Van 
der Schalie (1940) documented 31 specimens from six sites in the 
Chipola River system (an average of 5.2 per site).
    During the status survey, 33 sites within the historical range of 
this species on the Chipola River were sampled, including 12 of 16 (75 
percent) known historical sites. Live individuals were found at five 
sites (15 percent), including one historical site. An average of 3.7 
live individuals was found per site. Live individuals were located at 
one of the 12 historic resurveyed sites. Populations from Spring Creek 
(middle Chipola River system) and the Chattahoochee River system 
apparently have been extirpated, with the latter loss resulting in the 
extirpation of the Chipola slabshell from Alabama.
    No live specimens appeared to be juveniles, as the smallest live 
individual was 47 mm (1.9 in) in length. The Chipola slabshell has one 
of the most restricted ranges of any Apalachicolan Region mussel. 
However, it appears to be more tolerant of soft sediments than other 
species included in this rule, has potentially more habitat available 
than channel-dwelling species, and may co-occur with more silt-tolerant 
species in stream bank habitats with slower currents.
Purple Bankclimber--Elliptoideus Sloatianus (Lea, 1840)
    The purple bankclimber is a large, heavy-shelled, strongly 
sculptured mussel reaching lengths of 200 mm (8.0 in). A well-developed 
posterior ridge extends from the umbos to the posterior ventral margin 
of the shell. The posterior slope and the disk just anterior to the 
posterior ridge are sculptured by several irregular ridges that vary 
greatly in development. Umbos are low, extending just above the dorsal 
margin of the shell. Internally, there is one pseudocardinal tooth in 
the right valve and two in the left valve. The lateral teeth are very 
thick and slightly curved. Nacre color is whitish near the center of 
the shell becoming deep purple towards the margin, and very iridescent 
posteriorly. The Service recognizes Unio sloatianus Lea, 1840, Unio 
atromarginatus Lea, 1840, Unio aratus Conrad, 1849, and Unio 
plectophorus Conrad, 1950 as synonyms of Elliptoideus sloatianus.
    Elliptoideus sloatianus was included in the genus Elliptio until 
Frierson (1927) erected the subgenus Elliptoideus based on the presence 
of glochidia in all four gills instead of two gills, a characteristic 
of the genus Elliptio. Clench and Turner (1956) overlooked the work of 
Frierson (1927), placing the species under Elliptio. Subsequent 
investigators (e.g., Turgeon et al. 1988) have correctly assigned this 
species to the monotypic genus Elliptoideus.
    The purple bankclimber was described from the Chattahoochee River 
in Georgia. The type locality was restricted to the Chattahoochee River 
at Columbus, Georgia, by Clench and Turner (1956). In the ACF River 
system, the purple bankclimber was historically found throughout the 
mainstem and in a few of the largest tributaries in the Flint River 
system, in the vicinity of Dead Lake on the lower Chipola River 
mainstem (although not reported by van der Schalie (1940)), and along 
the mainstems of the Apalachicola and Chattahoochee rivers. The species 
occurred in the lower two-thirds of the mainstem of the Ochlockonee 
River, and in the Little River (Clench and Turner 1956, Butler 1993).
    During the status survey, 222 sites were sampled within the 
historic range of the purple bankclimber, including 14 of 27 (53 per 
cent) known historic sites. Live individuals were found at 41 (18 
percent) sites, with an average of 54 individuals per site. The purple 
bankclimber was found at six of the 14 historical sites. The species 
was found at 17 mainstem sites and one tributary site on the lower two-
thirds of the Flint River, at five sites in the Apalachicola River, and 
at 18 sites on the Ochlockonee River mainstem, mostly above Talquin 
Reservoir. Having been extirpated from the Chipola and Chattahoochee 
rivers, no extant populations occur in Alabama. Its range in the Flint 
and Ochlockonee River systems also has been reduced.
    It is uncertain if purple bankclimber populations are successfully 
recruiting young. Two specimens <70 mm (2.8 in) in length were 
collected from the Ochlockonee River during the survey; they were 53 mm 
(2.1 in) and 59 mm (2.3 in) in length. Based upon the large size 
attained by this species, both were possibly juveniles. The smallest 
specimen found during the survey in the ACF River system was 76 mm (3.0 
in) in length, a size that possibly represents a juvenile. Richardson 
and Yokley (1996) took six 0.25 meter (2.7 ft) square total substratum 
removal quadrat samples at a site below Jim Woodruff Dam in the 
Apalachicola River where the purple bankclimber was abundant, being the 
second most commonly encountered species. No specimens smaller than 133 
mm (5.2 in) were found, indicating a lack of recruitment at this site.
Previous Federal Action
    The fat threeridge, shinyrayed pocketbook, oval pigtoe, and purple 
bankclimber first appeared as category 2 species in the Service's 
notices of review for animal candidates that were published on January 
6, 1989 (54 FR 554) and on November 21, 1991 (56 FR 58804). At that 
time, a category 2 species was one that was being considered for 
possible addition to the Federal List of Endangered and Threatened 
Wildlife. Designation of category 2 species was discontinued in the 
February 28, 1996, Federal Register notice (61 FR 7596) (see also Issue 
103 in the ``Summary of Comments and Recommendations'' section). The 
Service determined that these four species plus the Gulf moccasinshell, 
Ochlockonee moccasinshell, and Chipola slabshell qualified as candidate 
species at the time of proposal for listing. A candidate species is a 
species for which the Service has sufficient information to propose it 
for protection under the Act. All seven species have been recommended 
for conservation status by Williams et al. (1992a) and Williams and 
Butler (1994).
    On November 18, 1993, the Service notified by mail (72 letters) 
potentially affected Federal and State agencies, local governments, and 
interested individuals that a status review was being conducted for 
these seven species. Ten comments were received. The Florida Division 
Office of the Federal Highway Administration stated that no bridge 
replacement projects were currently planned in northwest Florida, and 
that any future bridge replacement projects were not anticipated to 
affect these species, based on the localized and short-term impacts 
associated with these activities. The Federal Energy Regulatory 
Commission stated that they license twelve hydroelectric developments 
in the study area, and that issues concerning these species should be 
coordinated with the Office of Hydropower Licensing. The Fayette 
County, Georgia, Board of Commissioners expressed concern with the 
Service's belief that impoundments

[[Page 12670]]

had played such a major role in the demise of these species. The 
Alachua County, Florida, Environmental Protection Department indicated 
that none of the seven species were known or suspected to occur in that 
county. The Florida Game and Fresh Water Fish Commission expressed 
concern with how their plan to dredge the mouths of several silted in 
streams along the Apalachicola River to improve access for striped bass 
(Morone saxatilis) might affect these mussels. The Georgia Department 
of Natural Resources had questions concerning the distribution of these 
mussels, and sent a copy of regulations addressing the commercial 
harvest of mussels in Georgia. The Florida Natural Areas Inventory 
supported Federal listing of these species, and indicated that a 
portion of the Econfina Creek watershed where the Gulf moccasinshell 
and oval pigtoe occur is on a list for land purchase by the State of 
Florida. Three individuals with knowledge of freshwater mussels 
supported Federal listing of these species.
    The processing of this final rule conforms with the Service's final 
listing priority guidance published in the Federal Register on December 
5, 1996 (61 FR 64475). The guidance clarifies the order in which the 
Service will process rulemakings during fiscal year 1997. The guidance 
calls for giving highest priority to handling emergency situations 
(Tier 1) and second highest priority (Tier 2) to resolving the listing 
status of the outstanding proposed listings. This rule falls under Tier 
2. Presently, there are no pending Tier 1 actions in Region 4 and this 
is the Region's last outstanding Tier 2 action. Additionally, the 
guidance states that ``effective April 1, 1997, the Service will 
concurrently undertake all of the activities presently included in 
Tiers 1, 2, and 3'' (61 FR 64480). In a Federal Register notice 
published on October 23, 1997 (62 FR 55628), the guidance was extended 
beyond FY 1997 until such time as new guidance is published.
    In the development of this final rule, the Service has conducted an 
internal review of a draft of this rule and other Service-generated 
information. Based on this review, the Service has determined that 
there is no new information that would substantively affect these 
listing decisions and that additional public comment is not warranted.

Summary of Comments and Recommendations

    In the August 3, 1994, proposed rule (59 FR 39524), and through 
associated notifications, all interested parties were requested to 
submit factual reports and information that might contribute to the 
development of a final rule. Appropriate Federal and State agencies, 
county governments, scientific organizations, and interested parties 
were contacted by letter dated August 18, 1994, and were requested to 
comment. Legal notices were published in the following newspapers--the 
Albany Herald, Albany, Georgia, on August 20, 1994; the Atlanta 
Journal-Constitution, Atlanta, Georgia, on August 21, 1994; the 
Columbus Ledger-Enquirer, Columbus, Georgia, on August 21, 1994; the 
Macon Telegraph, Macon, Georgia, on August 20, 1994; the Thomasville 
Times-Enterprise, Thomasville, Georgia, on August 19, 1994; The 
Gainesville Sun, Gainesville, Florida, on August 18, 1994; the Jackson 
County Floridan, Marianna, Florida, on August 21, 1994; the Tallahassee 
Democrat, Tallahassee, Florida, on August 21, 1994; and The News-
Herald, Panama City, Florida, on August 22, 1994.
    In response to twelve formal requests during the first public 
comment period, the Service scheduled five public hearings in the 
three-State area within the historical range of these seven species. 
Prior to the hearings, the Service held five public informational 
meetings at the same sites as the public hearings. A notice of public 
meetings, public hearings, and reopening of the comment period was 
published in the Federal Register on December 12, 1994 (59 FR 63987), 
and in legal notices in the following newspapers--the Albany Herald, 
Albany, Georgia on January 6, 1995; The Atlanta Journal-Constitution, 
Atlanta, Georgia on January 8, 1995; the Columbus Ledger-Enquirer, 
Columbus, Georgia on January 5, 1995; the Dothan Eagle, Dothan, Alabama 
on January 7, 1995; the Montgomery Advertiser, Montgomery, Alabama on 
January 5, 1995; the Tallahassee Democrat, Tallahassee, Florida on 
January 6, 1995; the Jackson County Floridan, Marianna, Florida on 
January 8, 1995; and the Fayette News, Fayetteville, Georgia, on 
January 11, 1995. The comment period for the proposal closed on 
February 10, 1995.
    Public meetings were held at the Fayette County High School in 
Fayetteville, Georgia on January 5, 1995; at Chipola Junior College in 
Marianna, Florida on January 9, 1995; at the Opera House in Dothan, 
Alabama on January 10, 1995; at the Albany Civic Center in Albany, 
Georgia on January 11, 1995; and at the Convention and Trade Center in 
Columbus, Georgia on January 12, 1995. Public hearings were held at the 
same facilities in Fayetteville, Georgia on January 19, 1995; Dothan, 
Alabama on January 23, 1995; Marianna, Florida on January 24, 1995; 
Albany, Georgia on January 25, 1995; and Columbus, Georgia, on January 
26, 1995.
    In a Federal Register notice dated April 24, 1995 (60 FR 20072), 
the Service reopened the comment period on this proposal until May 5, 
1995, to allow for consideration of numerous comments received after 
the previous deadline (February 10, 1995) and to provide an opportunity 
for further comment. Legal notices were published in the following 
newspapers--the Albany Herald, Albany, Georgia on April 21, 1995; The 
Atlanta Journal-Constitution, Atlanta, Georgia on April 24, 1995; the 
Columbus Ledger-Enquirer, Columbus, Georgia on April 21, 1995; the 
Dothan Eagle, Dothan, Alabama on April 26, 1995; the Montgomery 
Advertiser, Montgomery, Alabama on April 22, 1995; the Tallahassee 
Democrat, Tallahassee, Florida on April 23, 1995; the Jackson County 
Floridan, Marianna, Florida on April 26, 1995; and the Fayette News, 
Fayetteville, Georgia on April 26, 1995.
    During the April 10, 1995, to April 26, 1996, listing moratorium, 
studies involving some of these proposed species were conducted in the 
ACF River system. To accept this new information, the Service published 
a notice in the Federal Register (61 FR 36020) on July 9, 1996, 
reopening the comment period until July 26, 1996. Legal notices were 
published in the following newspapers--the Albany Herald, Albany, 
Georgia on July 14, 1996; The Atlanta Journal-Constitution, Atlanta, 
Georgia on July 17, 1996; the Columbus Ledger-Enquirer, Columbus, 
Georgia on July 14, 1996; the Dothan Eagle, Dothan, Alabama on July 14, 
1996; the Montgomery Advertiser, Montgomery, Alabama on July 14, 1996; 
the Tallahassee Democrat, Tallahassee, Florida on July 14, 1996; the 
Jackson County Floridan, Marianna, Florida on July 14, 1996; and the 
Fayette News, Fayetteville, Georgia on July 14, 1996.
    The Service received hundreds of written comments and many oral 
statements presented at the public hearings and received during the 
comment periods. All pertinent comments have been considered in the 
formulation of this final rule. The proposed listings were supported by 
the U.S. Forest Service, the Environmental Protection Agency (EPA), and 
the States of Alabama (Department of Conservation and Natural 
Resources) and Florida (Department of Environmental Protection and Game 
and Fresh Water Fish Commission [FGFWFC]). The congressional 
delegations of the three States opposed the proposed listings. The 
following is

[[Page 12671]]

a summary of the comments, concerns, and questions (referred to as 
``Issues'' for the purposes of this summary) and the Service's response 
to each. Comments of similar content have been grouped together.
    Issue 1: Numerous commenters thought that the status survey was 
insufficient to make listing determinations for these seven species. 
Issues of concern included sampling methodologies, specimens collected, 
sites sampled, interpretation of historical data, whether sampling for 
juveniles had been adequate, and evidence of recent reproduction and 
recruitment. Other issues raised included the need for quantitative 
sampling, the percentage of historical sites sampled, how historical 
sites were selected for sampling, the evidence for the decline of these 
species, whether newly discovered sites represented new colonization by 
these mussels, and the reproductive viability of remaining populations.
    Response: Explanations of sampling methodology, specimens 
collected, sites sampled, and analysis of historical data have been 
included under ``Status Survey'' and ``Species Accounts'' in the 
Background section. Other issues associated with the status survey are 
discussed below.
    Quantitative sampling is not essential to determine the status of 
rare riverine mussel species (Miller and Payne 1988). Mussel 
populations are often distributed non-randomly (Downing and Downing 
1992). Even where habitats appear to be uniform, mussels tend to be 
distributed unevenly (Downing 1991). For these reasons, random 
transect-type quantitative sampling is less efficient than choosing 
sites based on criteria such as available habitat (G.L. Warren, FGFWFC, 
in litt. 1995).
    The Service compiled 300 historical site records from the ACF and 
Ochlockonee River systems; 108 of these sites had records of one or 
more of these proposed species. Research into historical mussel 
collections since the status survey was completed has yielded 
additional historical sites not reported in Butler (1993). The 
percentage of historical sites in the ACF and Ochlockonee River systems 
resurveyed for the seven species during the status survey ranged from 
40 to 75 percent, while the percentages of resurveyed historical sites 
in the ACF and Ochlockonee River systems that still supported live 
specimens of the seven species ranged from eight to 43 percent. 
Detailed analyses of these data are presented under ``Status Survey'' 
and ``Species Accounts'' in the ``Background'' section. Many historical 
sites had been visited more than once by other researchers or 
collectors prior to the status survey. If evidence indicated the 
species had disappeared from a historical site, and there was little 
probability of currently finding it, survey efforts were not expended 
there.
    The Service believes the newly discovered sites do not represent 
newly colonized sites, but sites that have existed historically but 
have not been previously sampled by collectors (see ``Status Survey'' 
under Background).
    The fat threeridge, shinyrayed pocketbook, Gulf moccasinshell, and 
oval pigtoe were historically considered rare, but widespread and 
locally abundant (Clench and Turner 1956). Mussel populations were 
decimated in the Chattahoochee River in the vicinity of Columbus, 
Georgia, by the early part of this century (Clench and Turner 1956). 
The river-dependent mussel species along the entire Chattahoochee River 
mainstem now appear to be extirpated (Butler 1993).
    Determination of sexual maturity in these species would require 
sectioning to locate mature gametes; determining age would require 
sectioning the shells (Neves and Moyer 1988); this was not within the 
scope or intent of the status survey. The Service considered shells to 
represent juveniles if they were less than one-quarter of the maximum 
size for each species. Based on the adult sizes typical of these seven 
mussel species, very few juvenile specimens were located during the 
status survey. While substrate samples were not taken, the survey 
biologists located thousands of smaller species of bivalves and snails. 
These included the ubiquitous Asian clam (Corbicula fluminea), 
pleurocerid (Elimia spp.) and other snails, and the iridescent lilliput 
(Toxolasma paulus), a mussel species rarely exceeding 32 mm (1.25 in) 
in total length. The Service believes that if significant recruitment 
was occurring in the seven species, more juvenile and small shells 
would have been located.
    Juveniles were also represented in some museum collections. 
Specimens of purple bankclimber as small as 26 mm (1.0 in) in length 
were represented in museum collections while the smallest specimen 
located during the status survey was 53 mm (2.1 in). The occurrence of 
juvenile specimens in museum collections substantiated population 
viability and indicated recent reproduction at the time the historical 
collection was made.
    Richardson and Yokley (1996) employed total substratum removal of 
six 0.25 m (2.7 ft) quadrats at each of three sites. They found three 
juvenile individuals of the fat threeridge in the lower Apalachicola 
River, but no evidence of recruitment of the purple bankclimber below 
Jim Woodruff Dam on the same river. These two species were both common 
and represented the second most abundant species at their respective 
sites. The fat threeridge population sampled is the largest known (J. 
Brim Box, USGS, pers. comm.). These data indicate that the fat 
threeridge is experiencing limited recruitment, but that there is no 
evidence of recruitment in the purple bankclimber at these sites.
    Brim Box and Dorazio (in press) took 2,867 substrate core samples 
(representing a composite 4.23 m (45.5 ft) square) for mussels at 30 
sites in the ACF system. No specimens of any of the 7 species in this 
rule were located in the 2,867 core samples, although juveniles of a 
few common species were found. Brim Box and Dorazio (in press) also 
took 2,867 0.25 m (2.7 ft) square quadrat samples, without total 
substratum removal, for mussels. No juveniles of the seven species were 
found.
    Richardson and Yokley (1996) stated that their work demonstrated 
that unequivocal evidence of recruitment can be found with minimal 
sampling effort. However, most literature on this subject demonstrates 
that the collection of juveniles is a low probability event (Kat 1982, 
Neves and Widlak 1987, Stansbery 1995). Quadrat sampling has 
consistently been determined to be inadequate for rare species (Neves 
et al. 1980, Kovalak et al. 1986, Neves and Odum 1989). The extreme 
patchiness of mussel distributions makes quantitative surveys 
expensive, time consuming, and not the best method to determine the 
population status of rare species (Miller and Payne 1988). The large 
number of substratum samples necessary to confirm recent recruitment is 
also disruptive to the stable benthic habitat essential to these and 
other riverine species (A.E. Bogan, North Carolina State Museum, pers. 
comm.).
    Issue 2: Several commenters said that the author of the proposed 
rule stated in a published paper that major portions of the 
Apalachicola and Ochlockonee rivers were ``virtually unsurveyed.''
    Response: What that statement referred to was that few historical 
sampling sites existed on the Apalachicola and lower Ochlockonee rivers 
at that time (Butler 1989). Subsequent surveys on the Apalachicola (35 
sites) and Ochlockonee River (24 sites) mainstems have provided 
adequate information to evaluate the status of the species considered 
in this rule.
    Issue 3: A few respondents asserted that comparing historical 
survey sites

[[Page 12672]]

with status survey sites is difficult because of differing collection 
techniques and the dynamic nature of streams (what was suitable habitat 
decades ago could now be very unsuitable due to various factors). One 
commenter urged the Service to use collection methods employed by early 
collectors to thoroughly sample streams.
    Response: The Service agrees that there may have been changes in 
habitat suitability over time. To compensate for this factor, Center 
biologists surveyed upstream and downstream of historical sites. While 
streams are dynamic, the proportions of riffle, run, and pool habitats 
remain fairly constant. Based on human influences over the past two 
centuries, the Service believes that available habitat for these 
mussels has diminished significantly (see Factor A in the ``Summary of 
Factors Affecting the Species'' section).
    Issue 4: One malacologist (mussel expert) asked if it would be 
possible to time-code the map symbols in the status survey report so 
that the distribution found in this study could be distinguished from 
that of earlier collections.
    Response: The distributional data could be time-coded; however, 
time-coding collections was not essential to determine the status of 
the seven mussels.
    Issue 5: Two malacologists suggested that some of these species 
have always been rare according to the literature, and that population 
declines could not be proven. One respondent questioned how many of the 
species existed historically compared to now.
    Response: Van der Schalie (1940) gathered data on Chipola River 
mussels from collections taken between 1915 to 1918 and included actual 
numbers of mussels from various sites in the drainage. A comparison of 
this historical data with the status survey results indicates a 
significant reduction in the numbers of at least two species in the 
Chipola River. Historically, 470 oval pigtoe specimens were collected 
from nine sites (an average of 52 per site) in the Chipola River versus 
35 specimens collected from six sites (an average of six per site) 
during the status survey. Historically, 166 specimens of the Gulf 
moccasinshell were known taken from eleven sites (an average of 15 per 
site) versus no specimens collected in the status survey.
    Clench and Turner (1956) indicated that some species (e.g., the fat 
threeridge and oval pigtoe) were rare and only locally abundant. They 
documented 10 to 15 specimens/meter (0.9 to 1.4 specimens/ft) square of 
fat threeridge over a 200 m (656 ft) stretch of Dead Lake (Chipola 
River). The fat threeridge apparently disappeared over 20 years ago in 
Dead Lake and was not found live there during the status survey. Except 
for the purple bankclimber, which is abundant at a few sites, these 
species are now rare range-wide and are not abundant at any known sites 
(see ``Species Accounts'' in the ``Background'' section).
    Issue 6: Two respondents stated that Federal listing of the purple 
bankclimber was not warranted because the species was abundant at some 
sites in the lower Flint and upper Ochlockonee rivers. One of these 
individuals further stated that he was confident that juveniles of this 
species were common.
    Response: The purple bankclimber is the most abundant of the seven 
mussels; however, no additional information on purple bankclimber 
abundance or recruitment was provided to the Service by these 
commenters. Recent sampling efforts on the Apalachicola River 
(Richardson and Yokley 1996) located only large individuals, indicating 
a lack of recruitment in this species.
    Issue 7: One commenter indicated that the Gulf moccasinshell still 
exists at several sites in the Chipola River system.
    Response: Van der Schalie (1940) reported 166 Gulf moccasinshells 
taken from eleven sites (an average of 15 specimens per site) in the 
Chipola River system, but none were located during the status survey. 
The Service received information on a recently discovered population in 
Baker Creek, in the Chipola River system, after publication of the 
proposal (see ``Species Accounts'' in the ``Background'' section), but 
the commenter provided no specific location or other information.
    Issue 8: Several commenters questioned the Service's statements 
regarding impoundments, including status survey efforts in 
impoundments, impact of impoundments upon these species, and the purple 
bankclimber's tolerance of impoundments.
    Response: Much riverine habitat in the ACF system has been 
converted to slack-water impoundments, particularly in the 
Chattahoochee River; however, verifiable pre-impoundment records of 
these species are uncommon (see Factor A in the ``Summary of Factors 
Affecting the Species'' section). Museum records confirm that some of 
the Ochlockonee River mussel fauna was inundated and lost at the upper 
end of Talquin Reservoir. Many historical collections came from the 
Chattahoochee River in the vicinity of Columbus, Georgia. Although 
exact locality data is generally lacking, several impoundments in this 
reach of river permanently reduced available riverine habitat for 
mussels.
    During the status survey, 39 reservoir sites were surveyed; none of 
the seven species were found in permanently impounded river reaches. 
None of these species are known to successfully reproduce and recruit 
under impoundment conditions. The reference to the purple bankclimber's 
tolerance of impounded conditions was based on a mussel relocation 
project funded by the U.S. Army Corps of Engineers (Corps). Purple 
bankclimbers from the Apalachicola River survived twelve months in 
laboratory tanks at the USGS research facility in Gainesville, Florida 
(Hamilton et al. 1996). However, the mussels were maintained in flow-
through tanks with currents. The experiment does not indicate that the 
purple bankclimber can survive and reproduce under impounded 
conditions.
    Issue 9: Two commenters questioned the expertise of the Center 
biologists who carried out the status survey.
    Response: The project leader of the status survey has 20 years 
experience with mussel research and surveys. The field leader has an 
M.S. degree in aquatic sciences and seven years field experience in 
aquatic biology. Field biologists, with one exception, had education in 
aquatic biology ranging from the B.S to Ph.D. level. Two scientists 
associated with the project have published scientific papers on mussel 
surveys and endangered species. The Service believes that all 
individuals involved in the survey were well qualified.
    Issue 10: One commenter questioned the adequacy of the sampling 
done by the status survey biologists, noting that various status survey 
field notes (e.g., the water was too cold, too turbid, or too deep) 
indicated that sampling was inadequate and that portions of the field 
data should be discarded.
    Response: The survey biologists employed the most appropriate 
sampling techniques based upon the habitat conditions present at each 
site. When high water precluded sampling, sites were usually revisited 
in lower water conditions to sample. The Service believes that the 
information gathered during field work is reliable and supports the 
determinations made in this rule.
    Issue 11: One commenter assumed that when the survey biologists 
checked a mussel for the presence of mature glochidia the mussel was 
stressed or even killed. Another respondent questioned the Service's 
recording of laboratory data, noting that an entire collection of over 
one hundred

[[Page 12673]]

individuals of a common species was comprised of all females.
    Response: During the status survey, some voucher mussels were 
preserved and brought to the laboratory for analysis, including 
inspection for glochidia. Most of the specimens were returned unharmed 
to the substrate from which they were collected. The species referred 
to by the respondent as consisting of only females were members of the 
genus Elliptio. This genus does not exhibit obvious external 
differences between the sexes; glochidia must either be present or 
gonadal tissues sectioned to determine sex. Laboratory notes on this 
collection stated that glochidia were not present (or ``NP'' on the 
data sheets) for any individual. The commenter apparently misconstrued 
``NP'' as meaning ``female, glochidia not present.'' Although their sex 
could not be determined, it is likely that both sexes were represented 
in the sample.
    Issue 12: Some respondents contended that the Service had not 
sampled the Escambia, Yellow, and Choctawhatchee rivers, where there 
were historical records of two of these species.
    Response: There is one historical record of the Gulf moccasinshell 
in the Yellow River (1963) and four records from the Choctawhatchee 
River in the 1930's. The Service examined over 30 collections taken 
from these watersheds over the past few decades. The Gulf moccasinshell 
did not occur in any of these collections. The Service believes this 
species is extirpated from the Yellow and Choctawhatchee River systems.
    Clench and Turner (1956) confused the shinyrayed pocketbook with 
the southern sandshell (Lampsilis australis) and erroneously stated 
that the shinyrayed pocketbook's range included the Choctawhatchee 
River. Johnson (1970), Heard (1979), and Williams and Butler (1994) 
clarified the range of the shinyrayed pocketbook as comprising only the 
ACF and Ochlockonee River systems. There are no records of any of the 
seven species from the Escambia River system. Collections made by the 
Center between 1993 and 1995 in this drainage corroborate this 
information.
    Issue 13: One respondent commented that the Service's diving 
regulations precluded divers from collecting in navigable river 
channels, thus making it impossible to assess mussel populations there.
    Response: Service diving regulations do not preclude sampling in 
navigable channels. Many dives using SCUBA were made in navigable 
channels during the status survey, and the Service believes that mussel 
populations in such areas were adequately sampled.
    Issue 14: One commenter stated that $27,000 was not adequate to 
conduct the status survey for the seven proposed mussels.
    Response: The Service's Jacksonville, Florida, Field Office 
provided $27,000 in initial funding and $12,000 during the survey. 
Total expenditures for the status survey were over $110,000. The 
Service believes the status survey was adequate to determine the status 
of these species.
    Issue 15: Various commenters were concerned that the scientific 
data associated with the status survey were not subjected to proper 
peer review.
    Response: The information supporting these determinations was 
extensively peer reviewed according to Service policy (see paragraph 
following the Service's response to Issue 107 in the ``Summary of 
Comments and Recommendations'' section for a discussion of peer 
review).
    Issue 16: Several respondents stated that any decision to list 
these species should be deferred until data is available on habitat 
requirements, fish hosts, and threats to the mussels and their host 
fish.
    Response: Although such data will be important in recovery for 
these species, they are not required under the listing factors under 
section 4(a) of the Act. To delay these listings until such data become 
available might preclude the species from being listed until recovery 
becomes less likely or extinction occurs.
    Issue 17: As gravid specimens were sometimes documented, some 
commenters questioned the Service's use of the term ``lack of 
reproductive viability'' in the proposed rule.
    Response: In the proposed rule, the Service stated that there was 
little evidence to suggest that populations of the seven mussel species 
were reproductively viable. This statement was based on the fact that 
no known juveniles were collected during the status survey. In this 
final rule, the Service has used the phrase ``lack of recruitment'' in 
its discussions of mussel reproductive status. This term more 
accurately defines the current status of these mussels.
    Issue 18: Several commenters thought that the Service had failed to 
determine potential host fish status, contending that missing hosts may 
be the primary cause of their decline. Two malacologists stated that if 
their fish hosts were gone, the mussels were ``functionally extinct''; 
a third asked that if this were so, why spend time and effort listing 
them?
    Response: As discussed under ``Reproductive Biology'' in the 
``Background'' section, the fish hosts for some of these species are 
not currently known. Without specific host fish information, it would 
be premature to spend considerable efforts and funding on fish 
sampling. Population and distribution information of potential host 
fish is not necessary to justify listing these species.
    Loss or depletion of fish host populations may be a primary factor 
in declines of some of the seven mussels. A loss of riverine habitat 
has probably also affected fish populations (see Factor A in the 
``Summary of Factors Affecting the Species'' section).
    If some of these seven mussel species are ``functionally extinct,'' 
recovery may still be possible by restoration of required fish host 
populations to the ecosystem. Regardless of the environmental factors 
responsible for the decline of these mussels, if one or more of the 
listing criteria are met, section 4 of the Act requires that the 
species be listed.
    Issue 19: One commenter was not convinced that mussels were 
important, while numerous malacologists and other commenters stated 
that mussels serve as excellent water quality indicators and barometers 
of aquatic ecosystem health.
    Response: Section 2(a) of the Act recognizes that species have 
intrinsic values (i.e., aesthetic, ecological, educational, historical, 
recreational, and scientific) to the nation, and the section 4 listing 
criteria do not require other justifications. However, mussels are of 
demonstrable value to man. Their longevity, relative immobility, and 
filter feeding habits make them among the best available indicators of 
environmental quality in aquatic systems. Mussels are highly 
susceptible to sedimentation and pollutants and provide an early 
warning of the deterioration of water and habitat quality. They 
accumulate heavy metals and other contaminants in their tissues and 
shells, serving as effective test organisms for contaminants studies.
    Native Americans and early settlers fed extensively on mussels, as 
shown by the large deposits of shell material in middens (Parmalee et 
al. 1982). In the first half of this century, mussels supported a large 
pearl button industry in the United States (McGregor and Gordon 1992). 
The cultured pearl industry harvests thousands of tons of shell from 
eastern rivers (Baker 1993), and cultured pearls are a multi-billion 
dollar global industry. Mussels are important organisms for biological 
studies, particularly because of their diverse methods of attracting 
host fish.

[[Page 12674]]

    Mussels serve an important ecological function by filtering excess 
nutrients from the water, improving water clarity so sunlight may 
promote rooted aquatic vegetation growth, thereby increasing habitat 
complexity and species diversity. Several vertebrate species, including 
mammals, birds, turtles, and fish feed regularly on mussels (Fuller 
1974). Their shells provide substrate diversity and a place for many 
types of invertebrates to colonize. This function is particularly 
important in homogenous sandy coastal plain rivers where hard surfaces 
are rare.
    Issue 20: Two malacologists questioned the Service's statements 
regarding the impacts of various human activities on the mussels, 
whereas other malacologists thought that their imperilment was easily 
documented given the extensive available literature. Others questioned 
the use of personal communications and subjective terms (e.g., maybe, 
unknown) in the proposed rule and at public meetings.
    Response: Additional references documenting Service conclusions 
have been added in this final rule (see ``Background'' and ``Summary of 
Factors Affecting the Species'' sections). The Service believes it 
appropriate to consider reliable unpublished reports, non-literature 
documentation, and personal communications with experts in making 
listing determinations.
    Issue 21: Several commenters thought that natural factors (e.g., 
floods) and not just the factors of human origin, should be considered 
in the species' imperilment.
    Response: Natural factors were considered in terms of threats to 
these species (see Factors C and E in the ``Summary of Factors 
Affecting the Species'' section).
    Issue 22: Two commenters questioned the Service's statement 
concerning lack of adequate flushing on the Ochlockonee River to rid 
the channel of silt and detritus below Talquin Reservoir.
    Response: One survey site in the Ochlockonee River below Talquin 
Reservoir had silt and detritus deposits extending from bank to bank. 
Under normal conditions, these materials are confined to slackwater 
areas, where they settle out in low or no-flow conditions. Low flow 
releases from Talquin Reservoir may be contributing to this situation.
    Issue 23: One commenter stated that these species' lack of 
reservoir tolerance may be incorrect, and that it was possible that 
mussels had not had enough time to reestablish themselves in the newly 
created benthic habitat created by Chattahoochee River impoundments.
    Response: There is no evidence that any of these seven mussels can 
successfully reproduce and recruit under impoundment conditions. Their 
habitat requirements generally consist of stable substrates, usually 
gravel, and other rocky materials in stream channels with currents. 
Habitat conditions created in impounded rivers consist of softer 
sediments (i.e., silt, mud, sand) and minimal currents (except at 
reservoir heads). Impoundments also change other physical and chemical 
characteristics of rivers (see Factor A in the ``Summary of Factors 
Affecting the Species'' section).
    Issue 24: Numerous commenters maintained that the results of a 
Corps-sponsored study on mussel translocation were relevant to the 
proposed listings, and that the comment period should have been 
extended until study results were available for public scrutiny.
    Response: The Corps investigated the feasibility of translocating 
four mussel species, including the purple bankclimber, in the 
Apalachicola River below Jim Woodruff Dam (Hamilton et al. 1996). This 
study will not provide additional information on the status of these 
species and does not justify further extension of the comment period.
    Issue 25: Several respondents stated that the Service cannot prove 
which, if any, human activities actually affect mussels. Conversely, a 
few malacologists stated that determining the direct relationship of 
these impacts would be a waste of research time and taxpayer dollars.
    Response: Although the precise role of the factors causing the 
decline of these species will never be known, there is information 
available on how human activities affect these and other species of 
mussels (see ``Background'' section and Factor A in the ``Summary of 
Factors Affecting the Species'' section).
    Issue 26: A few malacologists questioned the rationale for 
distinguishing between endangered and threatened; one of them 
criticized the lack of criteria for making such distinctions. One 
malacologist wondered how the Service determined that the narrowly 
distributed Chipola slabshell was threatened and not endangered. They 
also wondered at what point information was sufficient to list a 
species.
    Response: The Act defines an endangered species as a species 
threatened with extinction throughout all or a significant portion of 
its range, and a threatened species as a species in danger of becoming 
endangered throughout all or a significant portion of its range within 
the foreseeable future. The decision to propose a species as endangered 
or threatened is based solely on the best scientific and commercial 
data available after conducting a review of the status of the species. 
For the application of these definitions to the seven mussels in 
general, and the Chipola slabshell in particular, see ``Summary of 
Factors Affecting the Species'' and ``Species Accounts,'' respectively.
    Issue 27: One commenter stated that these seven species were 
imperiled in 1970, and if the species are still extant, these listings 
are long overdue.
    Response: The Service believes that the status survey was essential 
to determine the current status of these species before proposing them 
for listing. The Service carries out status surveys and listing 
actions, subject to a priority system published in the Federal Register 
on September 21, 1983 (48 FR 43098), and contingent on the availability 
of funding, personnel, and supportive information.
    Issue 28: Several commenters thought that the Service had 
overstated potential commercial utilization and take by biological 
supply companies of two species, that Georgia harvest regulations 
aiding in conservation had been understated, and that mussel 
identification training courses were needed.
    Response: Much of the commercial shell harvest in the southeast now 
takes place in west Tennessee and north Alabama. Although shells from 
the ACF River system are of poor quality, some have been included in 
shell shipments (J. Brim Box, USGS, pers. comm.). Demand for shell in 
recent years has pushed prices high enough that collectors have 
searched widely for unexploited shellbeds. The fat threeridge and 
purple bankclimber are so similar to the more common threeridge and 
washboard (Megalonaias nervosa) that take is a potential problem. 
Training and the development of educational materials will be 
considered as tasks when the recovery plan is prepared for these 
species.
    The Service agrees that the practice of dissecting mussels in 
introductory laboratory courses is no longer widespread. However, large 
species, such as the fat threeridge and purple bankclimber, may still 
be collected for this purpose (see factor B under ``Summary of Factors 
Affecting the Species'').
    Regulation of commercial harvest in Georgia has changed since the 
proposed rule was drafted; this has been

[[Page 12675]]

addressed in the final rule (see Factor D in the ``Summary of Factors 
Affecting the Species'' section for discussion of State regulations 
affecting these species).
    Issue 29: One commenter thought it was inappropriate for Service 
staff to recommend that no mussels should be harvested from the ACF and 
Ochlockonee River systems when some of the seven species were abundant.
    Response: Although some of these species occur in large numbers at 
a few sites, the Service believes the current status of the species 
does not justify a harvest.
    Issue 30: One commenter stated that much field data is gathered by 
amateurs, and the Service should recognize the value of this 
information. Two malacologists thought that we overestimated the number 
of shell clubs and amateurs, and accordingly overstated their threat to 
these species from collecting.
    Response: The Service acknowledges the significant role amateur 
malacologists have played in the development of our current knowledge 
of freshwater mussels. Most early mussel collections, including most of 
the type material used to describe these seven species, were collected 
by amateur naturalists. Amateurs continue to make important 
contributions to the knowledge of mussels. The Service agrees that the 
potential threat from shell club collectors is minimal (see Factor C in 
the ``Summary of Factors Affecting the Species'' section).
    Issue 31: Two malacologists commented that the Service may have 
taken an alarmist view with the proposal. One malacologist believed the 
Service was proposing to list aquatic snails that were abundant and 
unthreatened, and doubted the data used to support the listing of the 
mussels.
    Response: Based on the best available scientific and commercial 
data and peer review, the Service believes that listing under the Act 
is appropriate for these species (see ``Summary of Factors Affecting 
the Species'' section).
    Issue 32: A few respondents stated that the taxonomy of these 
species deserved further attention as the taxonomy of some species in 
the region was unresolved, and speculated that we may have been 
confused regarding which species we actually proposed.
    Response: Although the genetics of various mussel genera in the 
Apalachicolan Region are little known (Butler 1989), the species 
included in this final rule have been recognized by the malacological 
community for nearly a century. All meet the Act's definition of 
``species.''
    Issue 33: One commenter wanted to know why one mussel species 
addressed in the status survey report was omitted from the proposed 
rule.
    Response: The status survey included the round washboard 
(Megalonaias boykiniana). In December 1993, the Service learned of 
molecular genetics studies (Mulvey et al. in press) indicating that the 
round washboard might be conspecific with the widespread and common 
washboard. Based on this taxonomic uncertainty, this species was not 
proposed for listing. The same study, however, confirmed that the fat 
threeridge (Amblema neisleri) was a distinct species from the 
threeridge (A. plicata).
    Issue 34: One commenter suggested that mussel populations in the 
relatively pristine, undisturbed Econfina Creek should be thriving 
because conditions for mussels are optimal.
    Response: Econfina Creek retains high water quality, but has been 
altered by Deer Point Reservoir on the lower portion of the creek. 
Although Gulf moccasinshell and oval pigtoe populations survive in this 
stream, the populations appear to be small. Other factors may explain 
why these two species occur in small numbers. Econfina Creek represents 
the western-most stream within the historical range of the oval pigtoe, 
and the Gulf moccasinshell's western-most extant population. Peripheral 
populations in a species' range are often small and scattered.
    Issue 53: One malacologist stated that Clench and Turner's (1956) 
survey of Apalachicolan Region streams referred to the mussel fauna as 
being depauperate, whereas the Service claimed that the region was well 
known for its high level of endemicity.
    Response: Clench and Turner (1956) stated ``* * * [the mussel] 
fauna of [the Apalachicolan Region] has been derived from the west, is 
depauperate (not rich in species), and must be fairly old.'' When 
compared to adjacent drainages to the west (e.g., Mobile Basin) and 
north (e.g., Tennessee River system), the fauna is relatively low in 
species diversity. However, the Apalachicolan Region has many endemic 
species (see ``Introduction'' in the Background section). About 30 of 
the 60 mussel species known from the region are endemic (Butler 1989, 
Williams and Butler 1994).
    Issue 54: Two malacologists suggested that disease and predators 
are not threats to these mussels, and unless information is otherwise 
available, references to these factors should be deleted.
    Response: Factor C (``Disease or Predation'') in the ``Summary of 
Factors Affecting the Species'' section notes that there is no specific 
information available on how disease and predation affect these 
mussels.
    Issue 55: One commenter believed that mussels were more common than 
indicated in the proposed rule, because hundreds, if not thousands, of 
mussels are eaten by muskrats in the vicinity of his property on the 
Chattahoochee River.
    Response: No populations of these seven species currently occur in 
the Chattahoochee River. The mussels in question may be the Asian clam 
(Corbicula fluminea), a well-known food of muskrats, or reservoir-
tolerant native mussels.
    Issue 56: One commenter questioned the relationship between mussel 
populations and habitat quality.
    Response: Many mussels require water free from excessive levels of 
sediments and contaminants (Fuller 1974, Havlik and Marking 1987). As 
benthic inhabitants, they are readily affected by sedimentation, and as 
filter feeders, they are highly susceptible to various contaminants 
(see Factor A in the ``Summary of Factors Affecting the Species'' 
section).
    Issue 57: Two malacologists questioned these mussels' decline when 
other species in the same habitat had viable populations. Another 
commenter thought the Service assumed that all seven mussels had 
similar reproductive characteristics.
    Response: Species occurring in the same habitat typically have 
differences in life histories or ecological requirements (e.g., in the 
case of mussels, different host fishes) that permit them to coexist. 
These species would not be expected to respond in the same way to 
ecological stress. The specific reproductive biologies of the seven 
mussels is largely unknown, but would not be expected to be the same.
    Issue 58: One commenter thought these mussels were always rare, and 
thus served a limited ecosystem function, and further stated that the 
Asian clam could fill their niche, thus minimizing a potential chain 
reaction from loss of the mussels in the ecosystem.
    Response: Historical information indicates that some of these 
species were once locally abundant; the purple bankclimber still occurs 
abundantly at a few sites. The introduced Asian clam has been common in 
Apalachicolan Region rivers since 1960 (Schneider 1967) (see Factor E 
in the ``Summary of

[[Page 12676]]

Factors Affecting the Species'' section). Although the Asian clam may 
have become an increasingly important food for some predators (e.g., 
the muskrat), the long-term ecological consequences of its colonization 
are unknown.
    Issue 59: One respondent stated that data were not provided to 
substantiate claims that the Asian clam may be responsible for the 
imperilment of the Ochlockonee moccasinshell.
    Response: Sickel (1973) and Bass and Hitt (1974) indicate that 
Asian clam populations are dense in the ACF River system. This final 
rule contains additional information on how Asian clams may be 
impacting these seven species (see Factor E in the ``Summary of Factors 
Affecting the Species'' section).
    Issue 60: Several malacologists predicted that the exotic zebra 
mussel (Dreissena polymorpha) will inevitably increase the probability 
of extinction for the seven species based upon the impacts of this non-
native species in midwestern river systems.
    Response: If the zebra mussel invades the ACF system, it may be a 
serious threat to these species (see Factor E in the ``Summary of 
Factors Affecting the Species'' section).
    Issue 61: One commenter stated there is scientific evidence that 
certain dredging, navigation, waste water discharges, silvicultural, 
and agricultural activities may actually benefit filter feeders through 
nutrient enrichment, flow regime modification, and temperature 
modulation.
    Response: The commenter provided no specific references. The 
Service believes significant changes in water quality, including large 
increases in sediments, decrease in flow due to impoundments, and 
nutrient increases, have been generally detrimental to the native 
mussel fauna (Weber 1981, Sheehan et al. 1989, Goudreau et al. 1993).
    Issue 62: One commenter stated that, in certain parts of the world, 
mussels were used to clean up toxic waste waters, and wondered why 
these species seemed to be more susceptible to toxins when all they had 
to cope with were agricultural runoff and waste water treatment plant 
effluents. The individual wanted to know what chemicals were the most 
toxic to mussels.
    Response: Mussels are filter feeders that continually pass large 
volumes of water through their bodies. Mussels take in heavy metals and 
other contaminants and store them in their tissues or incorporate them 
into their shells. This allows them to effectively filter pollutants 
from water, but only if the species' toxicity threshold is not exceeded 
or its reproductive capacity is not impaired.
    Cadmium may be the most toxic heavy metal to mussels (Havlik and 
Marking 1987). Other heavy metals, ammonia, and chlorine also appear to 
be particularly toxic to mussels, especially in the early life stages.
    Issue 63: Several respondents questioned the mussel listings if 
many of their populations are non-viable. If so, not only was recovery 
impossible, but the Service should not have expended funds for mussel 
surveys.
    Response: These mussel populations have been significantly reduced 
in numbers and now exist only as fragmented populations in altered 
habitats (see ``Species Accounts'' in the ``Background'' section). 
Although some populations may not be viable, this does not preclude 
listing. Such populations could be augmented with juveniles produced 
through artificial propagation or with reproducing adults from another 
population.
    Issue 64: Several respondents stated that because the Service's 
recovery record was poor, additional species should not be listed. 
Another implied that the proposal did not contain data needed to effect 
recovery or predict the species' recovery potential.
    Response: A species' recovery potential is not a factor in making a 
listing determination. Most endangered and threatened species reached 
that status over many decades due to habitat loss and other complex 
causes. Recovery of these species should not be expected to be rapid or 
easy. Recovery planning and implementation occur following a species' 
listing, as required by section 4(f) of the Act.
    Issue 65: A few malacologists thought that it was the Service's 
responsibility to see that life history studies on these species and 
research on the well-being of river ecosystems should be conducted.
    Response: In preparing the recovery plan for these species, the 
Service will consider the need for such research and incorporate it in 
the plan as appropriate.
    Issue 66: Numerous commenters believed these listings would 
significantly impact economies of the three States. One respondent 
stated that the Service had ``juggled'' the numbers regarding section 7 
consultations to mislead the public.
    Response: Based on its experiences with the Act and listed mussels, 
the Service does not believe the listing of these species will have a 
significant effect on the economy of the three States where they occur. 
A 1992 General Accounting Office audit found that 99.9 percent of all 
projects (18,211) that were reviewed under the Act between 1988 and 
1992 went forward unchanged or with only minor modifications. Only six 
projects were halted due to endangered species considerations.
    Issue 67: Numerous respondents stated that channel maintenance and 
barge navigation in the ACF River system would be shut down or severely 
curtailed if these species were listed.
    Response: Through the section 7(a)(4) conference requirement of the 
Act addressing species proposed for listing, the Service and the Corps 
have agreed on measures regarding channel maintenance operations that 
will avoid jeopardizing the mussel species present. These measures will 
continue to be implemented once the species are listed (see ``Available 
Conservation Measures'' section).
    Issue 68: One respondent wanted the Service to guarantee that there 
would be no financial hardship to industry, or that such costs should 
be borne by the Service. Another wanted to know the if Service would 
provide assurances regarding minimal potential impacts and restrictions 
resulting from these listings. Several respondents requested that the 
Service provide an analysis of the potential economic impacts of 
listing these species.
    Response: Under Section 4(b)(1)(A) of the Act, a listing 
determination must be based solely on the best scientific and 
commercial data available. The legislative history of this provision 
clearly states the intent of Congress to ``ensure'' that listing 
decisions are ``* * * based solely on biological criteria and to 
prevent nonbiological considerations from affecting such decisions * * 
*'' H.R. Rep. No. 97-835, 97th Cong., 2d Sess. 19 (1982). As further 
stated in the legislative history, ``* * * economic considerations have 
no relevance to determinations regarding the status of species * *  *'' 
Id. at 20. Because the Service is specifically precluded from 
considering economic impacts, either positive or negative, in a final 
decision on a proposed listing, the Service need not consider the 
economic impacts of listing these species.
    Issue 69: The Corps disagreed with the statement that 
channelization was a primary cause of habitat loss. They stated that 
sediment instability in maintained channels made these areas too 
unstable to maintain mussel communities.
    Response: The impacts of channel modifications are addressed in 
Factor A in the ``Summary of Factors Affecting the Species'' section.

[[Page 12677]]

    Issue 70: The Corps stated that turbidity from dredging is not as 
detrimental to benthic habitats as is runoff from streams along the 
Apalachicola River after thunderstorms.
    Response: Regardless of origin, impacts from sedimentation, 
siltation, and turbidity sources may continue to be a problem in 
portions of the ACF River system (see Factor A in the ``Summary of 
Factors Affecting the Species'' section).
    Issue 71: The Corps stated that the proposal did not provide 
evidence for the statement that dredging activities resuspend toxicants 
bound to sediments.
    Response: While organochlorine insecticides were detected in less 
than 10 percent of sediment and tissue samples taken in the ACF River 
system during 1992 and 1993, such compounds were formerly widely used 
in the basin (Buell and Couch 1995), are persistent in the environment, 
toxic to aquatic life, and partitioned into both sediments and the 
lipid reservoir of organisms (Day 1990, Burton 1992).
    Issue 72: One respondent stated that the proposals did not explain 
why impoundments were considered a primary cause of habitat loss. 
Another stated that if impoundments are implicated, dams would be 
required to be removed.
    Response: Reservoir impacts on mussels are well documented, and 
there is no evidence that any of the seven species can reproduce and 
successfully recruit in impoundments (see Factor A in the ``Summary of 
Factors Affecting the Species'' section). Although other factors 
contributed to the mussels' decline, the Service believes reservoirs 
were a significant factor. Since few if any of these species still 
occur in reservoirs, dam removal is not a Service goal, nor would the 
Act require such an action.
    Issue 73: One commenter feared that the listings would affect ACF 
River system water allocations under the Tri-State Water Study (TSW). 
The Department of Energy's Southeastern Power Administration was 
concerned that the mussel listings would require changes in reservoir 
operations that might ultimately affect power generation capabilities. 
Another individual thought the species were proposed at this time to 
impact the on-going TSW study.
    Response: The Service has no flow recommendations for these seven 
mussels. The listing proposal was prepared after the completion of the 
status survey according to normal listing priorities, and had no 
connection with the TSW. However, a review of potential effects from 
any proposed water allocation formula will be needed (see ``Available 
Conservation Measures'' section).
    Issue 74: Two malacologists stated that every human activity 
affecting these species and their habitats should not have been 
mentioned in the proposed rule; the Service should have focused on 
specific factors (i.e., sedimentation, suspended solids, pollution) 
with objective, supporting evidence.
    Response: The information in the ``Summary of Factors Affecting the 
Species'' section has been revised to emphasize the factors believed 
most important in the decline of these mussels.
    Issue 75: Some commenters disagreed with the Service's assertions 
regarding the inadequacy of riparian buffers, particularly for 
silvicultural activities. Another commenter stated that the Service 
overlooked the fact that the State of Georgia had a law protecting 
streamside buffers.
    Response: The discussion of riparian buffers has been modified to 
incorporate these comments (see Factor A in the ``Summary of Factors 
Affecting the Species'' section).
    Issue 76: Several commenters questioned the proposed rule's 
implication of poor silvicultural practices as contributing to the 
mussels' demise. One commenter feared there could be an impact to the 
industry, whereas others requested that data be made available to 
document habitat reduction as a result of these activities.
    Response: Normal silvicultural activities on private lands should 
not be affected by these listings (see ``Available Conservation 
Measures'' section). The discussion of silvicultural activities has 
been clarified in this final rule (see Factor A in the ``Summary of 
Factors Affecting the Species'' section).
    Issue 77: One commenter stated that timber is a long-term crop and 
clear-cutting leaves land generally undisturbed for 25 years or more.
    Response: Although clear-cutting may be conducted on a long-term 
basis, best management practices for silvicultural activities are 
important to protect stream habitats long after such activities have 
occurred (see Factor A in the ``Summary of Factors Affecting the 
Species'' section).
    Issue 78: One respondent stated that if the mussels were listed, 
subsequent recovery plans would restrict land use practices and private 
property rights. Another stated that if these species are listed, 
private individuals and businesses could be subject to sections 7, 9, 
and 10 of the Act.
    Response: Recovery plans include reasonable actions that the 
Service believes necessary to bring species back to the point they no 
longer need protection under the Act. They do not restrict land use 
practices and private property rights. The recovery planning process is 
designed to allow potentially affected segments of the public to 
participate in decision making and allows the special local knowledge 
of affected communities to be fully considered. Draft plans are made 
available for public review and comment, and all affected or interested 
individuals and groups are encouraged to participate.
    Listing will provide these species the protection of sections 7 
(Federal agency actions and consultations) and 9 (prohibitions) of the 
Act. Section 9 ``taking'' exemptions are available under both sections 
7 and 9. Section 7(b)(4) of the Act provides for incidental take 
involving Federal actions if such take is not likely to jeopardize 
listed species and if reasonable and prudent measures are implemented 
to minimize such take. For further discussion of Federal activities 
associated with these listings, see the ``Available Conservation 
Measures'' section.
    Section 10 of the Act provides for the issuance of permits to 
conduct otherwise prohibited activities. Through section 10 habitat 
conservation planning (HCP) there is an opportunity to provide species 
protection and habitat conservation for non-Federal development and 
land use activities that may result in incidental take of a listed 
species. For landowners and local governments, it provides long-term 
assurances that their activities will be in compliance with the 
requirements of the Act. Biologically, it provides the Service with a 
tool to offset the incidental take of listed, proposed, candidate, and 
other species by reconciling species conservation with economic 
development.
    Issue 79: One respondent wanted a clarification of the Service's 
term ``poor land-use practices.''
    Response: Poor land-use practices in the proposed rule referred to 
activities that cause excessive erosion and contribute to stream 
sedimentation, siltation, and turbidity. These include activities such 
as clearing or plowing to the edge of stream banks, or carrying out 
upland development without adequate silt screens or erosion control.
    Issue 80: Several respondents stated that the species' decline 
resulted from historical disturbances, and that present conditions had 
improved, making listing unnecessary. Another respondent realized the 
role of historical impacts,

[[Page 12678]]

but supported the listings and felt more should be done to protect the 
remaining populations.
    Response: Historical human activities have contributed to these 
species' current status, and some factors may continue to threaten 
these mussels (see Factor A in the ``Summary of Factors Affecting the 
Species'' section). Although certain factors affecting these species 
have improved, continuing threats to these species qualify them for 
listing. Listing will provide the Act's protective and recovery 
measures.
    Issue 81: Several respondents thought the agricultural community 
was being directly implicated in poor land use practices. Other 
respondents felt better documentation was needed concerning 
agricultural impacts, and believed that normal agricultural practices 
would be impacted from the listings.
    Response: Listing of these mussels should not affect normal 
agricultural practices (see ``Available Conservation Measures'' 
section). Implementation of agricultural best management practices has 
reduced erosion in the Apalachicolan Region, and the percentage of 
agricultural lands has declined as second-growth forest has replaced 
formerly cultivated lands (Couch et al. 1996). If best management 
practices are followed, the Service believes that agricultural 
activities will be compatible with the continued survival of these 
seven mussels.
    Issue 82: Several respondents stated that listing the mussels would 
adversely impact the gravel-mining industry.
    Response: Large-scale mining of stable substrate inhabited by these 
mussels would be detrimental to them. The mining of unsuitable habitat 
(i.e., unconsolidated substrates, substrates within impoundments) would 
not be likely to affect them. Gravel mining in the Chattahoochee River 
should be unaffected (see Factor A in the ``Summary of Factors 
Affecting the Species'' section).
    Issue 83: One commenter feared that these listings could cause 
modification, significant construction cost increases, or even 
abandonment of existing and planned waste water treatment plants. 
Another commenter wanted to know what would happen to municipalities 
that discharged effluents into streams inhabited by these species.
    Response: The Service has no information showing that current water 
quality standards threaten these species. At the time water quality 
standards for particular states are reviewed under section 402 of the 
Clean Water Act, the EPA will be required to consult with the Service 
on any standards that may affect listed species. In the course of the 
EPA review of Alabama's water quality standards, the Service's 
biological opinion (dated October 8, 1996) resulting from consultation 
with EPA determined that there was not sufficient information to 
determine whether the standards were likely to jeopardize the continued 
existence of some of the listed species found in Alabama. The opinion 
anticipated incidental take for a number of listed species, required 
modification of water quality standards to protect listed species, and 
specified monitoring and research conditions to determine if changes in 
the standards were necessary. The Service anticipates that future water 
quality standard consultations will follow a similar approach.
    Issue 84: The Corps recommended that a statement in the proposed 
rule regarding the prolonged release of toxic chemicals from a 
Department of Defense facility should be revised, and that the Service 
should have considered the long-term dilution factor.
    Response: A facility near Albany, Georgia, discharged an estimated 
3.6 billion liters (l) (0.95 billion gallons (g)) of rinse, stripping, 
cleaning, and plating solutions through a short canal into the Flint 
River from 1955 to 1977. The Corps stated that the flow rate in the 
Flint River provided an average dilution rate of 1:127,555 l (1:33,700 
g) over the 22-year period. Many of these toxicants were heavy metals 
used in plating solutions. Regardless of this dilution factor, the 
Service believes the long-term release of this effluent likely had, and 
may continue to have, a chronic toxic effect on Flint River mussel 
populations (see Factor A in the ``Summary of Factors Affecting the 
Species'' section) and deserves additional study.
    Issue 85: A few commenters questioned the threat of toxic chemical 
spills on highway and railway bridges over streams. Some commenters 
thought that any listing would hamper efforts to rebuild bridges washed 
out during major floods.
    Response: Toxic chemical spills can occur at highway, railway, and 
pipeline crossings, and industrial sites (see Factor A in the ``Summary 
of Factors Affecting the Species'' section). Section 7 consultations 
for bridge replacements are performed on a regular basis for aquatic 
species throughout the southeast; occasionally, species surveys are 
requested prior to construction. Most such projects do not affect, or 
have minimal effects on, listed species. These listings are not 
expected to affect bridge replacement.
    Issue 86: One commenter wanted to know why Federal protection was 
necessary if the listings would not affect individual activities.
    Response: The Act requires listing based on the five criteria in 
section 4(a) and does not allow for consideration of impacts, or a lack 
thereof, on individual activities as part of a listing decision.
    Issue 87: The Corps stated that the proposal provided minimal 
evidence to prioritize human activities that may have affected mussel 
habitat.
    Response: Additional information on such human activities has been 
provided in Factor A in the ``Summary of Factors Affecting the 
Species'' section.
    Issue 88: One respondent requested information relating to cost/
benefit ratios associated with recovery actions.
    Response: Costs associated with implementation of recovery tasks 
will be estimated when the recovery plan is developed for these 
species. Cost/benefit ratios are not calculated in recovery plans.
    Issue 89: One respondent asked what effect the listing would have 
on commercial fishermen.
    Response: The use of these mussels for bait would be a violation of 
section 9 of the Act. No other effects on commercial fishermen are 
anticipated.
    Issue 90: Several commenters believed the Service had 
misrepresented the science in the proposed rule, based upon an internal 
Service memorandum. Some individuals felt the Service had changed its 
position on the importance of human impacts after the proposed rule was 
published.
    Response: The Service believes the proposed rule was scientifically 
sound, as was confirmed by peer review. Regardless of editing changes 
in the draft, the proposed rule signed by the Service Director and 
published in the Federal Register on August 3, 1994 (59 FR 39524), 
represented the Service's position on the various threats to the seven 
mussels. In formulating this final rule, the Service has considered all 
substantive comments and re-examined these threats (see the ``Summary 
of Factors Affecting the Species'' section).
    The perception that the Service changed its position was apparently 
based on the description in the proposed rule of human activities (e.g. 
agriculture and forestry) that had impacted these species, versus the 
Service's explanation at public meetings that the listing would have 
little impact on such activities. Most of these activities are not 
directly regulated or monitored by the Service or other Federal 
agencies, and are, therefore, unlikely to be affected. Secondly, many 
human activities result in effects that are non-point in origin (e.g., 
erosion)

[[Page 12679]]

and are not easily attributable to a particular source. The ways in 
which these listings are expected to affect human activities are 
discussed in the ``Available Conservation Measures'' section below.
    Issue 91: EPA requested that the Service clarify the following 
statement in the proposal--``Existing authorities available to protect 
aquatic systems, such as the Clean Water Act [CWA] administered by EPA 
and the [Corps], have not been fully utilized and may have led to the 
degradation of aquatic environments in the Southeast Region, thus 
resulting in a decline of aquatic species.'' EPA also requested that 
the Service identify deficiencies in their implementation of the CWA 
regarding State adopted narrative and numeric water quality criteria, 
State water use classifications by streams occupied by these species, 
aquatic life criteria guidance values; and National Pollutant Discharge 
Elimination System (NPDES) permit procedures. Several respondents 
questioned the need to improve regional water quality, suggesting that 
existing regulations are adequate to protect the species, and that poor 
water quality had been corrected since the passage of the CWA.
    Response: Through implementation of the CWA, water quality has 
improved following the construction of advanced waste water treatment 
plants. Water quality criteria, however, were developed without 
specific knowledge of the tolerances of these seven mussels and 
previously listed mussels, which may be more sensitive than the species 
typically used to test waste water (Keller and Zam 1991, Keller 1993). 
Some mussel populations continue to decline even in areas that appear 
to have suitable physical habitat. Environmental factors including 
contaminants may still be adversely affecting the growth, reproduction, 
recruitment, and/or survival of these populations (see Factors A and E 
in the ``Summary of Factors Affecting the Species'' section). Little is 
known about the potential impacts of contaminants on fresh water 
mussels. Research is needed to address the lethal and sublethal effects 
of acute and chronic exposure to toxins for all life stages of mussels. 
This research will entail identifying appropriate surrogate species, 
devising test protocols, and conducting studies to evaluate the 
effectiveness of these criteria. The Service is currently working with 
EPA to develop a memorandum of agreement (MOA) that will address how 
EPA and the Service will interact relative to CWA water quality 
criteria, standards, and NPDES permits within the Service's Southeast 
Region. Until the MOA is developed and data are available to fully 
evaluate the effectiveness of current national water quality standards, 
the Service believes it is premature to attempt, in this final rule, to 
address any specific deficiencies and/or inadequacies that may exist in 
EPA's implementation of the CWA regarding the protection of water 
quality.
    Issue 92: One respondent questioned if the Service had complied 
with the National Environmental Policy Act in the development of this 
rule.
    Response: See ``National Environmental Policy Act'' section.
    Issue 93: A few respondents stated that current State and Federal 
laws, interagency regulations, permit guidelines, and voluntary 
programs governing land usage were sufficient to protect the mussels, 
and thus, questioned the need to provide additional protection when 
private property rights would be compromised.
    Response: The Service agrees that current State and Federal laws 
and regulations governing land use practices, if fully implemented, 
provide significant protection for these species. However, the current 
status of these seven species meets the listing criteria of the Act. 
Listing will provide the additional protective and recovery provisions 
of the Act.
    Issue 94: Several respondents stated that listing these species 
could be considered an unfunded mandate if State and local governmental 
agencies are required to expend funds to satisfy permit requirements 
for their protection.
    Response: The Act does not mandate State participation in the 
recovery of listed species, but the Service recognizes and is sensitive 
to the fact that costs of some projects may increase as a result of 
these listings. However, the decision to list the species is based on 
biological factors regarding status and threats.
    Issue 95: One respondent stated that the Service had not considered 
the benefits that the erosion control practices required by the U.S. 
Food Security Act have had on the aquatic environment.
    Response: The Service agrees that these requirements have 
benefitted mussels by reducing silt loads in streams.
    Issue 96: One respondent stated that if these species are listed, 
the public will not know when they are in violation of the Act until 
``after the fact.''
    Response: See the ``Available Conservation Measures'' section for 
activities the Service believes would likely constitute violations of 
section 9 of the Act.
    Issue 97: One commenter stated that if the Service reintroduced 
mussel populations, the public would not know where the reintroductions 
occurred, or the regulatory impacts resulting from these efforts.
    Response: Section 4(f)(4) of the Act requires the Service to 
provide public notice and an opportunity for public review and comment 
on all draft recovery plans. Establishment of an experimental 
population under section 10(j) of the Act would be done by regulation, 
thus, requiring the Service to identify the location of the population 
and provide for a public comment period. Any population determined to 
be an experimental population is treated as if it were listed as 
threatened for purposes of establishing protective regulations under 
section 4(d) of the Act. The special rule for the experimental 
population would contain the prohibitions and exceptions for that 
population.
    Issue 98: Numerous commenters stated that the Service had limited 
the public's opportunity to comment on the proposal by planning public 
hearings outside the affected area, during the Thanksgiving holidays, 
and at facilities too small to accommodate the public. They also stated 
that comment periods were too short, that the Service might refuse to 
pay for public hearing facilities, or had not planned to hold public 
meetings.
    Response: Section 4(b)(5) of the Act requires that one public 
hearing be held on proposed listing regulations, if requested. Meetings 
are discretionary and are held dependent on public interest and need. 
In conjunction with the proposed rule, the Service held five public 
information meetings followed by five public hearings in three States 
throughout the range of the mussels (see first part of ``Summary of 
Comments and Recommendations'' section). Meetings and hearings were 
scheduled to avoid holidays or other conflicts. Meeting and hearing 
sites contained seating well beyond the attendance needs at all events. 
Comments were accepted at the hearings and by mail; the comment period 
was opened four times, over a period of two years (59 FR 39524, 59 FR 
63987, 60 FR 20072, 61 FR 36020). The Service, therefore, believes 
there was adequate opportunity for public comment.
    Issue 99: Several commenters stated that the Service had made the 
determination to list these species prior to public consideration, 
based on the term ``final rule'' having been used by Service employees 
at a public meeting.
    Response: The Service recognizes that during the proposal period, 
the proper

[[Page 12680]]

terms relating to a regulatory decision are ``final decision'' and 
``final decision document.'' This final rule has been prepared after 
full consideration of all relevant comments and information received 
during the comment period.
    Issue 100: One respondent believed the Service had preconceived 
ideas and conclusions as to the species' status prior to conducting the 
status survey.
    Response: The seven species were considered to be category 2 
species prior to the status survey (see ``Previous Federal Action'' 
section), but this did not mean a decision had been made to list them. 
Many species for which status surveys are carried out are found not to 
meet the listing criteria of the Act.
    Issue 101: Several respondents stated that the Service does not use 
good science in the listing process; one respondent stated that the 
listings would be arbitrary and capricious. Several respondents 
believed that the Service had violated the Administrative Procedure 
Act, the Act's ``best scientific and commercial data available'' 
standard, and Constitutional guarantees of equal protection and due 
process.
    Response: The Service believes that this final rule incorporates 
the best available scientific and commercial information and complies 
with the Administrative Procedures Act.
    Issue 102: One individual stated that he was not provided an 
opportunity to comment on the status survey report and the proposed 
rule.
    Response: The comment periods, public meetings, and public hearings 
associated with the proposed rule (see ``Previous Federal Action'' 
section and the response to issue 98) provided extensive opportunities 
for interested parties to comment on or to request copies of Service 
documents.
    Issue 103: One respondent commented that the Service was under 
pressure to list as many as possible of the 3,000 species on the annual 
notices of review.
    Response: On February 28, 1996, (61 FR 7596) the Service revised 
its candidate species list, replacing an old system that listed nearly 
4,000 ``candidate'' species under three separate categories (see also 
``Previous Federal Action'' section). The old system led many people to 
the mistaken conclusion that the addition of thousands of species to 
the Federal List of Endangered and Threatened Wildlife and Plants was 
imminent. Under the revised list, only those species for which there is 
enough information to support a listing proposal are called 
``candidates.'' These were formerly known as ``category 1'' species. 
The proposal to list these seven mussels followed the Service's normal 
priorities and procedures.
    Issue 104: Several respondents stated that the Service already 
protects too many species and the country does not need any more listed 
species.
    Response: Section 4(a) of the Act requires species to be listed 
based on the five listing factors. The Act sets no limit on the number 
of species to be recognized as endangered or threatened.
    Issue 105: A few commenters stated that the Service had failed to 
designate critical habitat or was planning to designate critical 
habitat for these species. One respondent feared that designating 
critical habitat would halt navigation channel maintenance, whereas 
another thought the Service should determine the critical habitat 
necessary for their survival and then conduct an economic impact study.
    Response: Section 4(a)(3) of the Act requires the Service to 
designate critical habitat to the maximum extent prudent and 
determinable at the time a species is listed. The Service has 
determined that the designation of critical habitat for these seven 
species is not prudent (see ``Critical Habitat'' section).
    Issue 106: One commenter believed that any effort to delist a 
mussel once it was placed on the Federal list would require volumes of 
detailed data and be at the expense of local governments.
    Response: The Act provides the same criteria to reclassify or 
delist species as to list them. Subsequent to a listing, section 4(f) 
of the Act requires the Service to develop and implement recovery plans 
for all listed species. Recovery plans include goals for 
reclassification and delisting. Section 4(c)(2) of the Act further 
requires the Service to review the status of listed species every five 
years to determine if reclassification or delisting is appropriate. 
There is no obligation for local governments or other parties to 
provide information on the status of listed species or to initiate 
reclassification or delisting actions.
    Issue 107: One respondent claimed the Service missed the 
administrative deadline for publishing a final rule for these species. 
Based on our Federal Register notice of July 9, 1996, (61 FR 36021) to 
reopen the comment period, this commenter was unclear as to whether the 
mussels faced ``imminent threat'' on the basis of the Service statement 
that the proposals were a ``Tier 2 priority'' for listing.
    Response: The congressional moratorium on final decisions on 
proposed listings, from April 1995 to April 1996, precluded publication 
of a final rule for these species by the Act's administrative deadline 
of August 3, 1995 (see ``Previous Federal Action'' section). The 
Service published listing priority guidance to address the backlog of 
listing activities as a result of the moratorium (March 11, 1996 (61 FR 
9651), May 16, 1996 (61 FR 24722), September 17, 1996 (61 FR 48962), 
December 5, 1996 (61 FR 64475), and October 23, 1997 (62 FR 55268). The 
guidance assigned the processing of a final decision for these seven 
mussels to Tier 2 (resolving the listing status of outstanding proposed 
rules).
    The Service also solicited the expert opinions of 60 scientists 
with knowledge of mussels and sampling methodologies, including most 
North American malacologists. They were asked to comment on the 
adequacy of the status survey in supporting the proposed rule. 
Responses were received from 37 individuals and pertinent comments were 
incorporated into this final rule.
    Generally, the independent reviewers strongly supported the listing 
proposal. Many agreed with the Service's concerns about the threats to 
these species, including loss of riverine habitat, vulnerability of 
specific stages of the life histories, and impaired reproduction. Seven 
malacologists stated that the status survey was one of the most 
comprehensive studies they were aware of.
    Two malacologists suggested that the Service withdraw the proposed 
rule and conduct further studies, but provided no specific information 
justifying the withdrawal of the listing proposal. However, in a 
written statement read at two of the public hearings, one of these 
malacologists stated that ``* * * the integrity of the current study is 
not questioned * * *'' (P.Yokley, Jr., University of North Alabama, in 
litt. 1995).

Summary of Factors Affecting the Species

    After a thorough review and consideration of all information 
available, the Service has determined that the fat threeridge, 
shinyrayed pocketbook, Gulf moccasinshell, Ochlockonee moccasinshell, 
and oval pigtoe should be classified as endangered species, and the 
Chipola slabshell and purple bankclimber should be classified as 
threatened species. Procedures found at Section 4(a)(1) of the Act and 
regulations implementing the listing provisions of the Act (50 CFR part 
424) were followed. A species may be determined to be an endangered or 
threatened species due to one or more of the five factors described in 
section 4(a)(1). These factors and their application to

[[Page 12681]]

the fat threeridge (Amblema neislerii), shinyrayed pocketbook 
(Lampsilis subangulata), Gulf moccasinshell (Medionidus penicillatus), 
Ochlockonee moccasinshell (Medionidus simpsonianus), oval pigtoe 
(Pleurobema pyriforme), Chipola slabshell (Elliptio chipolaensis), and 
purple bankclimber (Elliptoideus sloatianus) are as follows.

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

    Historically, mussel faunas in the United States have declined 
extensively as an unintended consequence of human development (Havlik 
and Marking 1987, Neves 1993). The mussel fauna in much of the 
Apalachicolan Region has been negatively impacted by impoundments, 
siltation, channelization, and by water pollution. The cumulative 
effect of these factors on the aquatic ecosystems of the ACF River 
basin has not been systematically evaluated; an ongoing USGS National 
Water Quality Assessment is currently addressing this task (Couch et 
al. 1996).
    Impoundments have permanently altered a significant portion of the 
ACF River system, which has 16 mainstem impoundments. Impoundments 
affect mussels by altering current, substrate (Sickel 1981, Holland-
Bartels and Waller 1987), and water chemistry (Allan and Flecker 1993, 
Stansbery 1995), factors which are important to riverine mussels. Lack 
of mussel recruitment in impoundments may be due to loss of glochidia 
in the substrate, attacks on glochidia by microorganisms, or the 
juveniles' inability to survive in silt (Ellis 1929, Scruggs 1960, 
Williams 1969, Fuller 1974).
    The Chattahoochee River has 13 dams, including three locks and dams 
along its lower half; the lower mainstem is inundated for approximately 
400 km (248 mi). An additional 85 km (53 mi) of mainstem habitat are 
impounded upstream of Atlanta, making approximately 485 km (301 mi) of 
the mainstem's 700 km (434 mi) total length (69 percent) impounded. The 
lower portions of many tributaries were permanently flooded because of 
these reservoirs, including a known site for the shinyrayed pocketbook 
in Walter F. George Reservoir (Clench and Turner 1956).
    Impoundments have altered approximately 175 km (109 mi) of 600 km 
(372 mi), or 29 percent, of mainstem riverine habitat on the Flint 
River. Preimpoundment records from Seminole and Blackshear reservoirs 
exist for the fat threeridge and oval pigtoe (one site each), the Gulf 
moccasinshell and purple bankclimber (two sites each), and the 
shinyrayed pocketbook (three sites) (Clench 1955, Clench and Turner 
1956).
    Talquin Reservoir inundated approximately 32 km (20 mi) of riverine 
habitat (of a total of 278 km [172 mi] of mainstem, or 12 percent 
impounded) in the middle portion of the Ochlockonee River and the lower 
5 km (3 mi) of the Little River, its largest tributary. Preimpoundment 
records exist for four of these species from a site at the upstream end 
of Talquin Reservoir (Clench and Turner 1956). This impoundment may 
have flooded habitat for the Ochlockonee arcmussel, believed to be 
extinct (Williams and Butler 1994), and may block potential host fish 
movements for other mussels. The shinyrayed pocketbook, Ochlockonee 
moccasinshell, and oval pigtoe were absent downstream of the dam. Only 
occasional populations of the purple bankclimber were found in this 
portion of the river.
    Populations of the shinyrayed pocketbook, Gulf moccasinshell, and 
purple bankclimber have been isolated due to major impoundments on the 
Apalachicola, Flint, and Ochlockonee rivers. Smaller impoundments on 
tributary streams in the region have resulted in further population 
isolation of some of the species.
    A navigation channel is maintained on the Chattahoochee and 
Apalachicola rivers from Columbus, Georgia, to the Gulf Coast, a 
distance of approximately 325 km (200 mi), and the lower 50 km (30 mi) 
of the Flint River. River habitat and stable benthic substrates have 
been altered in significant portions of this system. None of these 
seven mussels occur in the navigation channels of the Chattahoochee or 
Flint rivers. The fat threeridge and the purple bankclimber occur in 
portions of the Apalachicola River that have a navigation channel. The 
Corps and the Service have agreed on procedures to minimize impacts to 
these species when navigation maintenance is carried out (see 
``Available Conservation Measures'' section).
    Many regional streams have increased turbidity levels due to 
siltation. These seven mussels probably attract host fishes with visual 
cues. Such a reproductive strategy depends on clear water. Turbidity is 
a limiting factor impeding sight-feeding fishes (Burkhead and Jenkins 
1991), and may have contributed to the decline of these seven species.
    Light to moderate levels of siltation are common in many 
Apalachicolan Region streams with populations of these seven species, 
while heavy siltation has occurred in the Piedmont, which is well known 
for its highly erodible soils. Most of the topsoil in the Piedmont was 
eroded by 1935 (Wharton 1978). Clench (1955) attributed the decline of 
the rich mussel fauna of the Chattahoochee River to erosion from 
intensive farming before the Civil War. The steep slopes characteristic 
of the Fall Line Hills and the Piedmont result in higher erosion rates 
than slopes on more level lands (Pimentel et al. 1995).
    Couch et al. (1996) indicated that all parts of the ACF Basin have 
been subject to alteration of forest cover. They attributed severe 
historical erosion and sedimentation in the Blue Ridge Province to 
mining and logging. The Service believes that while deforestation 
historically represented a threat to these mussels, current 
silvicultural activities following best management practices are 
compatible with the continued existence of the species (see Available 
Conservation Measures' section).
    Because of their sedentary characteristics, mussels are extremely 
vulnerable to toxic effluents (Sheehan et al. 1989; Goudreau et al. 
1993). There are discharges from 137 municipal waste water treatment 
facilities in the ACF River basin. Although the quality of effluents 
has improved since the 1980's due to improved waste water treatment and 
a 1990 phosphate detergent ban in Georgia, two-thirds of the 938 stream 
miles in the Georgia portion of the ACF River basin do not meet the 
designated water use classifications under the requirements of the 
Clean Water Act (Couch et al. 1996).
    Agricultural influences include nutrient enrichment from confined 
feeding of poultry and livestock (primarily in the Piedmont Province), 
and inputs of pesticides and fertilizers from row crop agriculture 
(primarily in the Coastal Plain) (Couch et al. 1996).
    An estimated 3.6 billion liters (0.95 billion gallons) of chemical-
laden rinse, stripping, cleaning, and plating solutions were discharged 
through a short canal into the Flint River from 1955 to 1977 at a 
Department of Defense facility in Albany, Georgia (P. Laumeyer, Fish 
and Wildlife Service, pers. comm.). The Service believes the long-term 
release of this effluent likely had, and may continue to have, a 
chronic toxic effect on Flint River mussel populations. The canal and 
other portions of the facility are a Superfund site.
    Abandoned battery salvage operations affect water quality in the 
Chipola River. Concentrations of heavy metals (e.g., chromium and 
cadmium) in Asian clams and sediments increased in samples taken 
downstream from two

[[Page 12682]]

operations (Winger et al. 1985). Dead Lake, on the lower mainstem, was 
considered a contaminant sink. Chromium was found at levels known to be 
toxic to mussels (Havlik and Marking 1987) in sediment samples from 
Dead Lake downstream (Winger et al. 1985). A large population of the 
fat threeridge has been extirpated in Dead Lake, possibly from such 
contamination.
    Residential development in Georgia is resulting in the conversion 
of farmland to subdivisions in areas relatively distant from the cities 
of Albany, Atlanta, and Columbus. Development and land clearing 
increases siltation from erosion, runoff and transport of pollutants 
from stormwater, and municipal waste water facility effluents. Lenat 
and Crawford (1994) found that in Piedmont drainages, urban catchments 
had higher maximum average concentrations of heavy metals than 
agricultural or forested catchments. Urban waterways may harbor human-
produced contaminants in concentrations sufficient to significantly 
affect fish health (Ostrander et al. 1995).
    Additional water supply impoundments may be planned to satisfy 
expanding urban and suburban demand. Any impoundments on streams that 
support these species may have impacts on their long-term survival. 
Impoundments on streams that do not harbor these species could be 
designed in ways to minimize or eliminate potential impacts to these 
mussels and their habitat downstream. Future impoundments, particularly 
in the metropolitan Atlanta area, could impact stream habitats where 
small populations of the shinyrayed pocketbook, Gulf moccasinshell, and 
oval pigtoe exist.
    In-stream and near-stream gravel mining has occurred in various 
portions of the Apalachicolan Region. Jenkinson (1973) recorded the 
shinyrayed pocketbook, oval pigtoe, Gulf moccasinshell, and ten other 
species in Little Uchee Creek, a tributary of the Chattahoochee River 
in Alabama. The creek had supported in-stream gravel mining; only a few 
shell fragments were found at Jenkinson's site in the status survey, 
although living shiny-rayed pocketbooks were found at another site in 
Little Uchee Creek. Gravel mining operations in the Chattahoochee River 
do not pose a threat to these mussels since no populations exist there 
now. However, where in-stream gravel operations are conducted in the 
vicinity of populations of these species, mussels may be displaced, 
crushed, or covered by bottom materials.
    Some artifact and fossil collectors have used suction dredges to 
scour benthic habitats in the ACF system. This can destroy mussel 
habitat at the collection site and resuspend silt, impacting downstream 
areas. In a study on the effects of suction dredging for gold on stream 
invertebrates, Harvey (1986) concluded that impacts from suction 
dredges can be expected to be more severe in streams with softer 
substrates (e.g., sand, gravel), as is typical for most Apalachicolan 
Region streams.
    Many of the impacts discussed above occurred in the past as 
unintended consequences of human development in the Apalachicolan 
Region. Improved understanding of these consequences has led to 
regulatory (e.g., the Clean Water Act) and voluntary measures (e.g., 
best management practices for agriculture and silviculture) and 
improved land use practices that are generally compatible with the 
continued existence of these mussels. Nonetheless, the seven mussel 
species currently are highly restricted in numbers and distribution and 
show little evidence of recovering from historic habitat losses.

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

    The threeridge (a relative of the fat threeridge) and the washboard 
(Megalonaias nervosa), which is superficially similar to both the fat 
threeridge and purple bankclimber, are heavily utilized as sources of 
shell for nuclei in the cultured pearl industry. The Service has been 
informed by commercial shell buyers that shells from the ACF River 
system are of poor quality. However, shell material from this area may 
be used as ``filler'' for higher quality material from elsewhere (J. 
Brim Box, USGS, Gainesville, Florida, pers. comm.). In the 1980's, the 
price of shell increased, resulting in increased competition for the 
harvesting of shell beds in the Apalachicolan Region.
    Biological supply companies have used the Flint River and possibly 
the Ochlockonee River as sources for large mussel specimens, including 
the purple bankclimber and possibly the fat threeridge, to sell to 
academic institutions for use in laboratory studies. The practice of 
dissecting mussels in introductory laboratory courses is no longer 
widespread, and the threat posed to large species such as the fat 
threeridge and purple bankclimber is probably decreasing.
    Nonetheless, harvest of the fat threeridge and purple bankclimber 
for these purposes could decimate their remaining populations (see 
Factor D in this section). The increasing rarity of these mussels 
potentially makes them more appealing to shell collectors. Revealing 
specific stream reaches harboring these species could pose a threat 
from collectors (see ``Critical Habitat'' section below).
    State regulations now in effect should deter or prevent the threat 
from commercial collecting (see Factor D below).

C. Disease or Predation

    Diseases of mussels are virtually unknown; this factor is not 
currently known to affect these seven species.
    Juvenile and adult mussels may serve as prey for various animals, 
mostly fishes, turtles, birds, and mammals (Fuller 1974). The muskrat 
has been implicated in potentially jeopardizing recovery of federally 
listed mussels (Neves and Odum 1989). Although muskrats are not common 
within the range of these species, Piedmont populations of the 
shinyrayed pocketbook, Gulf moccasinshell, and oval pigtoe in the upper 
Flint River system may be subject to some degree of muskrat predation.

D. The Inadequacy of Existing Regulatory Mechanisms

    A scientific collecting permit is required in the State of Georgia 
to collect mussels for scientific purposes. Commercial harvest in 
Georgia is allowed only for the washboard. Mechanical harvest of 
mussels is illegal. Commercially harvested mussels in Georgia must be 
large enough to not pass through a 102 mm (4.0 in) ring. The harvest 
season is from April 1 to August 31. Hand-picking mussels requires a 
resident or non-resident fishing license. Despite permit requirements, 
enforcement is difficult and there are no present restrictions on sites 
of harvest or quantity taken in Georgia. Although not a target species, 
the purple bankclimber is superficially similar to the commercially 
exploited washboard to be potentially threatened (see Factor B in this 
section). The fat threeridge is probably extirpated from Georgia 
(Butler 1993).
    Mussel harvest in Florida is deemed non-profitable due to the 
absence of large populations of desirable species and poor shell 
quality, but there is potential for harvest of the fat threeridge and 
purple bankclimber. In July 1996, the State of Florida enacted a 
moratorium on commercial mussel harvest (G.L. Warren, FGFWFC, pers. 
comm.). Limited collection of mussels under a State permit is allowed 
for scientific or other non-commercial purposes. Alabama has commercial 
harvest guidelines, including species

[[Page 12683]]

size limits, restricted harvest areas, and closed seasons. Of these 
seven mussels, only the shinyrayed pocketbook is found in Alabama, and 
it is not a commercially sought species.

E. Other Natural or Manmade Factors Affecting Its Continued Existence

    Because of slow growth and relative immobility, mussel 
recolonization of impacted river reaches is a lengthy process, achieved 
by dispersal of newly metamorphosed juveniles via infected host fish, 
passive adult movement downstream (Neves 1993), and active migration or 
passive movement downstream of small individuals (Kat 1982). 
Establishment of self-sustaining populations requires decades of 
immigration and recruitment, even for common species that may occur in 
high densities (Neves 1993). A mussel species should be considered 
stable only when active population recruitment is demonstrated and a 
significant number of viable populations exists (A.E. Bogan, North 
Carolina State Museum, in litt. 1995).
    The exotic Asian clam (Corbicula fluminea) has invaded all of the 
rivers where these seven mussels occur. First reported from the 
Apalachicolan Region about 1960 (Schneider 1967), this species may 
compete with native mussels for nutrients and space (Clarke 1983, 
1986). Densities of Asian clams are sometimes high in Apalachicolan 
Region streams, with estimates ranging from approximately 100/m (9/ft) 
square (Flint River, Sickel 1973) to over 2,100/m (195/ft) square 
(Santa Fe River, Bass and Hitt 1974). In some streams, the substrate 
has changed from homogenous silty sand or sand to one with a gravel-
like component comprised of huge numbers of live and dead Asian clams.
    Buttner and Heidinger (1981) estimated that an Asian clam could 
filter an average of 347 milliliters (12.1 ounces) of water per hour. 
Clarke (1983) hypothesized that at a density of 250/m (22/ft) square in 
a 1 m (3.3 ft) deep river flowing at 1.6 km (1 mi) per hour, Asian 
clams could filter 95 percent of the phytoplankton out of the water 
over 38 river km (24 river mi). Clarke (1986) believed the Asian clam 
posed a threat to the survival of the endangered Tar spinymussel 
(Elliptio steinstansana) in North Carolina. Heard (1977) noted the 
disappearance of local ACF River system mussel populations concurrent 
with colonization of the Asian clam. Kraemer (1979) stated that the 
Asian clam may outcompete native mussels in altered streams.
    Another introduced bivalve, the zebra mussel (Dreissena 
polymorpha), has caused the extirpation of numerous native mussel 
populations and may pose a threat to these mussels in the future. 
Introduced into the Great Lakes in the late 1980's, this exotic species 
has been rapidly expanding its range in the South, but has not been 
reported yet from Apalachicolan Region streams.
    The complex life cycle of mussels increases the probability that 
weak links in their life history will preclude successful reproduction 
and recruitment (Neves 1993). Egg formation and fertilization are 
critical phases in the life history, because many mussels fail to form 
eggs (Downing et al. 1989) or fertilization is incomplete (Matteson 
1948). Fertilization success has been shown to be strongly correlated 
with spatial aggregation; excessively dispersed populations may have 
poor success (Downing et al. 1993). The need for specific fish hosts 
and the difficulty in recolonizing areas where mussels have been 
decimated are other life history attributes which make them vulnerable 
(see ``General Biology'' in the ``Background'' section).
    These seven species have been rendered vulnerable to extinction due 
to significant habitat loss, range restriction, and population 
fragmentation and size reduction. Most of their populations have been 
extirpated from the Piedmont portion of their historical ranges, four 
of five species are extirpated from Alabama, and none of the species 
remain in the Chattahoochee River. The restricted distribution of these 
seven species also makes localized populations susceptible to 
catastrophic events and collection.
    The Service has carefully assessed the best scientific and 
commercial information available regarding the past, present, and 
future threats faced by these seven mussels in determining to make this 
final rule. Based on this evaluation, the preferred action is to list 
the fat threeridge, shinyrayed pocketbook, oval pigtoe, Gulf 
moccasinshell, and Ochlockonee moccasinshell as endangered species, and 
the Chipola slabshell and purple bankclimber as threatened species.
    The fat threeridge, shinyrayed pocketbook, oval pigtoe, Gulf 
moccasinshell, and Ochlockonee moccasinshell are in danger of 
extinction throughout all or a significant part of their range as 
follows:
    Fat threeridge: This species historically occurred in the Flint, 
Apalachicola, and Chipola rivers, and is currently known from six sites 
on the latter two rivers. It has been extirpated from the Flint River, 
which included most of its historic range. It has disappeared from most 
of the historical sites where it was formerly found, and only seven 
percent of sampled sites within the historic range still have live 
individuals. Limited recruitment of young appears to be occurring only 
at one site on the lower Apalachicola River.
    Shinyrayed pocketbook: This species historically occurred in the 
ACF, Chipola, and Ochlockonee River systems. It now occurs at only 21 
percent of the historical sites sampled, and is extirpated from the 
mainstems of the ACF rivers. Populations have declined significantly in 
the Chipola River. The species occurs at 29 sites in tributaries of the 
ACF rivers and the Chipola and Ochlockonee rivers. Only two sites show 
evidence of recruitment; however, the largest known population shows no 
signs of recruitment.
    Gulf moccasinshell: This species historically occurred in the ACF, 
Chipola, Choctawhatchee, and Yellow River systems and in Econfina 
Creek. It is no longer present at most of the historical sites sampled, 
and is apparently extirpated from the Apalachicola, Choctawhatchee, and 
Yellow rivers. There are 13 known sites, none showing evidence of 
recruitment.
    Ochlockonee moccasinshell: This species occurred historically only 
in the Ochlockonee River system. It was formerly known from eight 
sites. It is now known only from two sites, where there is no evidence 
of recruitment. Only three live individuals have been found since 1974.
    Oval pigtoe: This species was historically found throughout the 
ACF, Chipola, Ochlockonee, and Suwannee River systems, and in Econfina 
Creek. It occurred at one-third of the historical sites sampled. It has 
been extirpated from the mainstem of the Chattahoochee River, 
representing a significant portion of its historical range; occurrences 
in the Flint and Suwannee River systems have decreased from 32 to 12. 
The species is currently known to occur at 26 sites, with no evidence 
of recruitment.
    The Chipola slabshell and purple bankclimber are likely to become 
endangered species in the foreseeable future throughout all or a 
significant part of their range:
    Chipola slabshell: This species occurred historically at eight 
sites in the Chipola River and one site in the Chattahoochee River 
system. It is currently known from five sites in the Chipola River. 
This species appears to have some tolerance of soft sediments and, 
therefore, has more habitat potentially available than the other 
species in this rule. It was, however, found only at nine percent of 
the sites sampled within its historic range, and

[[Page 12684]]

there is no current evidence of recruitment.
    Purple bankclimber: This species historically occurred in the ACF, 
Chipola, and Ochlockonee River systems. It currently occurs in the 
Apalachicola, Flint, and Ochlockonee rivers, with 41 sites known. It 
may be extirpated from the Chattahoochee and Chipola rivers. There is 
some evidence of recruitment at one site in the Apalachicola River.

Critical Habitat

    Critical habitat is defined in section 3 of the Act as: (i) the 
specific areas within the geographical area occupied by a species, at 
the time it is listed in accordance with the Act, on which are found 
those physical or biological features (I) essential to the conservation 
of the species and (II) that may require special management 
considerations or protection; and (ii) specific areas outside the 
geographic 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'' means the use of all methods and procedures 
needed to bring the species to the point at which listing under the Act 
is no longer necessary.
    Section 4(a)(3) of the Act, as amended, requires that, to the 
maximum extent prudent and determinable, the Secretary designate 
critical habitat at the time a species is determined to be endangered 
or threatened. The Service's regulations at 50 CFR 424.12(a)(1) state 
that designation of critical habitat is not prudent when one or both of 
the following situations exist: (1) The species is threatened by taking 
or other activity and the identification of critical habitat can be 
expected to increase the degree of threat to the species or (2) such 
designation of critical habitat would not be beneficial to the species. 
The Service finds that designation of critical habitat is not prudent 
for these species. Such a determination would result in no known 
benefit to these species, and designation of critical habitat could 
further pose a threat to them through publication of their site-
specific localities.
    Critical habitat designation, by definition, directly affects only 
Federal agency actions. Since these seven mussel species are aquatic 
throughout their life cycles, Federal actions that might affect these 
species and their habitats include those with impacts on stream channel 
geometry, bottom substrate composition, water quantity and quality, and 
stormwater runoff. Such activities would be subject to review under 
section 7(a)(2) of the Act, whether or not critical habitat was 
designated. 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 a listed species or to destroy or 
adversely modify its critical habitat. The fat threeridge, shinyrayed 
pocketbook, Gulf moccasinshell, Ochlockonee moccasinshell, oval pigtoe, 
Chipola slabshell and purple bankclimber have become so restricted in 
distribution that any significant adverse modification or destruction 
of their occupied habitats would likely jeopardize their continued 
existence. This would also hold true as the species recovers and its 
numbers increase. As part of the development of this final rule, 
Federal and State agencies were notified of the mussels' general 
distributions, and they were requested to provide data on proposed 
Federal actions that might adversely affect the species. Should any 
future projects be proposed in areas inhabited by these mussels, the 
involved Federal agency will already have the general distributional 
data needed to determine if the species may be impacted by their 
action, and if needed, more specific distributional information would 
be provided. Therefore, habitat protection for these seven species can 
be accomplished through the section 7 jeopardy standard and there is no 
benefit in designating currently occupied habitat of these species as 
critical habitat.
    Recovery of these species will require the identification of 
unoccupied stream and river reaches appropriate for reintroduction. The 
Service is currently working with the State and other Federal agencies 
to periodically survey and assess habitat potential of stream and river 
reaches for listed and candidate aquatic species within the ACF and 
Ochlockonee river systems and the Yellow and Santa Fe rivers. (For the 
Apalachicola River, for example, see the discussion under ``Available 
Conservation Measures'' below.) This process provides up-to-date 
information on instream habitat conditions in response to land use 
changes within watersheds. Information generated from surveys and 
assessments is disseminated through Service coordination with other 
agencies. The Service will work with State and Federal agencies, as 
well as private property owners and other affected parties, through the 
recovery process to identify stream reaches and potential sites for 
reintroduction of these species. Thus, any benefit that might be 
provided by designation of unoccupied habitat as critical will be 
accomplished more effectively with the current coordination process and 
is preferable for aquatic habitats which change rapidly in response to 
watershed land use practices. In addition, the Service believes that 
any potential benefits to critical habitat designation are outweighed 
by additional threats to the species that would result from such 
designation, as discussed below.
    Though critical habitat designation directly affects only Federal 
agency actions, this process can arouse concern and resentment on the 
part of private landowners and other interested parties. The 
publication of critical habitat maps in the Federal Register and local 
newspapers, and other publicity or controversy accompanying critical 
habitat designation may increase the potential for vandalism as well as 
other collection threats (See Factor B under ``Summary of Factors 
Affecting the Species''). For example, in 1993 the Alabama sturgeon was 
proposed for endangered status with critical habitat (59 FR 33148). 
Critical habitat included the lower portions of the Alabama, Cahaba, 
and Tombigbee rivers in south Alabama. The proposal generated thousands 
of comments with the primary concern that the actions would devastate 
the economy of the State of Alabama and severely impact adjoining 
States. There were reports from State conservation agents and other 
knowledgeable sources of rumors inciting the capture and destruction of 
Alabama sturgeon. A primary contributing factor to this controversy was 
the proposed designation of critical habitat for the sturgeon.
    The seven mussel species addressed in this proposal are especially 
vulnerable to vandalism. They all are found in shallow shoals or 
riffles in restricted stream and river segments and are relatively 
immobile and unable to escape collectors or vandals. They inhabit 
remote but easily accessed areas, and they are sensitive to a variety 
of easily obtained commercial chemicals and products. Because of these 
factors, vandalism or collecting could be undetectable and 
uncontrolled.
    All known populations of these seven mussel species occur in 
streams flowing through private lands. One threat to all surviving 
populations of these seven species appears to be pollutants in 
stormwater runoff that originate from private land activities (see 
Factor A). Therefore, the survival and recovery of these mussels will 
be highly dependent on landowner cooperation in reducing land use 
impacts. Controversy resulting from critical habitat designation has 
been known to reduce private

[[Page 12685]]

landowner cooperation in the management of species listed under the Act 
(e.g., spotted owl, golden cheeked warbler). The Alabama sturgeon 
experience suggests that critical habitat designation could affect 
landowner cooperation within watersheds occupied by these seven 
mussels.
    Based on the above analysis, the Service has concluded critical 
habitat designation would provide little additional benefit for these 
species beyond those that would accrue from listing under the Act.
    The Service also concludes that any potential benefit from such a 
designation would be offset by an increased level of vulnerability to 
vandalism or collecting, and by a possible reduction in landowner 
cooperation to manage and recover these species. The designation of 
critical habitat for these seven mussel species is not prudent.

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 local agencies, private 
organizations, 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)(4) requires Federal agencies to confer 
informally with the Service on any action that is likely to jeopardize 
the continued existence of a proposed species or result in destruction 
or adverse modification of proposed critical habitat. If a species is 
listed subsequently, Section 7(a)(2) of the Act requires Federal 
agencies to ensure that activities they authorize, fund, or carry out 
are not likely to jeopardize the continued existence of 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.
    The Service notified Federal agencies that may have programs which 
could affect these species. Navigation maintenance on the Apalachicola 
River has the potential to impact the fat threeridge and purple 
bankclimber. These species are concentrated in two short reaches of the 
Apalachicola River that have only minimal dredging requirements. The 
Service and the Corps have agreed on the following criteria to address 
potential navigational impacts--(1) dredging and dredge material 
disposal can continue without further coordination with the Service in 
all areas where these mussels were not found during the status survey 
and in areas where the Corps has dredged or disposed dredge material 
since 1991; and (2) in areas that do not meet the first criterion, the 
Corps will consult further with the Service to determine if 
modifications of their channel maintenance activities are needed to 
protect the species. These further consultations may require the Corps 
to conduct additional mussel surveys prior to initiating channel 
maintenance activities. The Corps and the Service have established an 
effective working relationship on this issue, and will make every 
effort to continue navigation maintenance while protecting listed 
mussels. If conflict arises, potential measures for resolution include 
relocation of the channel alignment, disposal areas, or mussels.
    A water supply reservoir is under consideration on Line Creek in 
the upper Flint River system, in Cowetta and Fayette counties, Georgia. 
This project would inundate historical habitat for the shinyrayed 
pocketbook and oval pigtoe. The project applicant, Fayette County, will 
need to secure a permit pursuant to section 404 of the CWA. In survey 
efforts made subsequent to the status survey, however, none of these 
seven species were found, and there is very little suitable habitat in 
the area to be affected by the proposed dam and reservoir. One live 
shinyrayed pocketbook was found several miles downstream of the 
proposed dam site, but the Service does not believe the proposed 
project will affect this area. Therefore, listing of this species will 
not affect the project.
    The Corps is responsible for operating the reservoirs and channel 
structures in the ACF Basin for a variety of purposes, including 
navigation, flood control, water supply, fish and wildlife resources, 
recreation, and hydropower. Water allocation formulae are being 
developed in conjunction with an Interstate Water Compact involving the 
States of Alabama, Florida, and Georgia, to provide for the needs of 
these States. Any allocation formula that might affect the seven 
mussels will require section 7 consultation between the Corps and the 
Service.
    No other specific Federal actions were identified that would likely 
affect any of the species. Federal activities for which potential 
effects to the species would be reviewed include the issuance of 
permits for reservoir construction, stream alterations, waste water 
facility development, water withdrawal projects, pesticide 
registration, agricultural assistance programs, mining, road and bridge 
construction, Federal loan programs, water allocation, and hydropower 
relicensing. However, it has been the experience of the Service that 
nearly all section 7 consultations have been resolved so that the 
species has been protected and project objectives met.
    The Act and implementing regulations found at 50 CFR 17.21 and 
17.31 set forth a series of general prohibitions and exceptions that 
apply to all endangered and threatened 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, 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 is also illegal to possess, sell, deliver, 
carry, transport, or ship any such wildlife that has been taken 
illegally. Certain exceptions apply to agents of the Service and State 
conservation agencies.
    Permits may be issued to carry out otherwise prohibited activities 
involving endangered and threatened wildlife species under certain 
circumstances. Regulations governing permits are at 50 CFR 17.22 and 
17.32. Such permits are available for scientific purposes, to enhance 
the propagation or survival of the species, and/or for incidental take 
in connection with otherwise lawful activities. For threatened species, 
permits also are available for zoological exhibition, educational 
purposes, or special purposes consistent with the purposes of the Act.
    It is the policy of the Service (59 FR 34272) to identify at the 
time of listing, to the maximum extent practicable, those activities 
that would not constitute a violation of section 9 of the Act. The 
intent of this policy is to increase public awareness of the effect of 
these listings on proposed and ongoing activities within a species'

[[Page 12686]]

range. During the public comment period, comments were received 
questioning the effect these listings would have on private landowners 
(see response to Issues 69, 76, and 81 in the ``Summary of Comments and 
Recommendations'' section), normal agricultural activities (see 
response to Issue 84), silvicultural practices (see response to Issue 
79), and commercial fishing (see response to Issue 92). The Service 
believes, based on the best available information as outlined in the 
``Summary of Comments and Recommendations'' section of this rule, that 
the aforementioned actions will not result in a violation of section 9 
provided the activities are carried out in accordance with any existing 
regulations, permit requirements, and best management practices. The 
Service also believes that most other human activities will not result 
in a section 9 violation. These include use of the river by boaters, 
anglers, and other existing recreational uses.
    Activities that the Service believes could potentially result in 
``take'' of these mussels include, but are not limited to, (1) 
unauthorized collection or capture of the species; (2) unauthorized 
destruction or alteration of the species' habitat (e.g., in-stream 
mining, channelization, discharge of fill material); (3) violation of 
any discharge or water withdrawal permit; and (4) illegal discharge or 
dumping of toxic chemicals or other pollutants into waters supporting 
these species.
    Activities not identified in the above two paragraphs will be 
reviewed on a case-by-case basis to determine if a violation of section 
9 of the Act may have occurred. The Service does not consider these 
lists to be exhaustive and provides them as information to the public.
    Questions regarding whether specific activities will constitute a 
violation of section 9 should be directed to the Field Supervisor of 
the Service's Jacksonville, Florida Field Office (see ADDRESSES 
section) or the Field Supervisor of the Service's Panama City, Florida 
Field Office (U.S. Fish and Wildlife Service, 1612 June Avenue, Panama 
City, Florida 32405, telephone 904/769-0552). Requests for copies of 
the regulations on listed species and inquiries regarding prohibitions 
and permits should be addressed to the U.S Fish and Wildlife Service, 
Ecological Services, 1875 Century Boulevard, Suite 200, Atlanta, 
Georgia 30345-3301 (404/679-7313).

National Environmental Policy Act

    The Fish and Wildlife Service has determined that an Environmental 
Assessment, as defined under the authority of the NEPA of 1969, need 
not be prepared in connection with regulations adopted pursuant to 
section 4(a) of the Act. A notice outlining the Service's reasons for 
this determination was published in the Federal Register on October 25, 
1983 (48 FR 49244).

Required Determinations

    This rule does not contain collections of information that require 
approval by the OMB under 44 U.S.C. 3501 et seq.

References Cited

    A complete list of all references cited herein, as well as others, 
is available upon request from the Field Supervisor (see ADDRESSES 
section).

Author

    The primary author of this final rule is Mr. Robert S. Butler, U.S. 
Fish and Wildlife Service, Asheville Field Office, 160 Zillicoa Street, 
Asheville, North Carolina 28801 (704/258-3939).

List of Subjects in 50 CFR Part 17

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

Regulation Promulgation

    Accordingly, the Service amends part 17, subchapter B of chapter I, 
title 50 of the Code of Federal Regulations, as follows:

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 section 17.11(h) by adding the following, in alphabetical 
order under CLAMS, to the List of Endangered and Threatened Wildlife:


Sec. 17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

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

[[Page 12687]]

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

    Dated: January 23, 1998.
Jamie Rappaport Clark,
Director, Fish and Wildlife Service.
[FR Doc. 98-6493 Filed 3-13-98; 8:45 am]
BILLING CODE 4310-55-P