[Federal Register Volume 78, Number 187 (Thursday, September 26, 2013)]
[Rules and Regulations]
[Pages 59269-59287]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-23356]
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DEPARTMENT OF THE INTERIOR
Fish and Wildlife Service
50 CFR Part 17
[Docket No. FWS-R4-ES-2012-0004; 4500030113]
1018-AY06
Endangered and Threatened Wildlife and Plants; Endangered Species
Status for the Fluted Kidneyshell and Slabside Pearlymussel
AGENCY: Fish and Wildlife Service, Interior.
ACTION: Final rule.
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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), determine
endangered species status under the Endangered Species Act of 1973
(Act), as amended, for the fluted kidneyshell (Ptychobranchus
subtentum) and slabside pearlymussel (Pleuronaia dolabelloides). These
two species are endemic to portions of the Cumberland and Tennessee
River systems of Alabama, Kentucky, Mississippi, Tennessee, and
Virginia. The effect of this regulation is to add these species to the
List of Endangered and Threatened Wildlife and to implement the Federal
protections provided by the Act for these species.
DATES: This rule is effective on October 28, 2013.
ADDRESSES: This final rule is available on the Internet at http://www.regulations.gov and at http://www.fws.gov/cookeville. Comments and
materials we received, as well as supporting documentation we used in
preparing this rule, are available for public inspection at http://www.regulations.gov. All of the comments, materials, and documentation
that we considered in this rulemaking are available by appointment,
during normal business hours, at: U.S. Fish and Wildlife Service,
Tennessee Ecological Services Field Office, 446 Neal Street,
Cookeville, TN 38501; telephone 931-528-6481; facsimile 931-528-7075.
FOR FURTHER INFORMATION CONTACT: Mary Jennings, Field Supervisor, U.S.
Fish and Wildlife Service, Tennessee Ecological Services Field Office,
446 Neal Street, Cookeville, TN 38501; telephone 931-528-6481;
facsimile 931-528-7075. If you use a telecommunications device for the
deaf (TDD), call the Federal Information Relay Service (FIRS) at 800-
877-8339.
SUPPLEMENTARY INFORMATION:
Executive Summary
Why we need to publish a rule. Under the Endangered Species Act, a
species warrants protection through listing if it is endangered or
threatened throughout all or a significant portion of its range.
Listing a species as an endangered or threatened species can only be
completed by issuing a rule. Elsewhere in today's Federal Register, we
designate critical habitat for the fluted kidneyshell and slabside
pearlymussel.
This rule lists the fluted kidneyshell and slabside pearlymussel as
endangered species.
The basis for our action. Under the Act, we may determine that a
species is endangered or threatened based on any of five factors: (A)
The present or threatened destruction, modification, or curtailment of
its habitat or range; (B) overutilization for commercial, recreational,
scientific, or educational purposes; (C) disease or predation; (D) the
inadequacy of existing regulatory mechanisms; or (E) other natural or
manmade factors affecting its continued existence. We have determined
these two mussel species are facing threats based on three of these
five factors (A, D, and E). Both species have been eliminated from more
than 50 percent of the streams from which they were historically known,
and from more than 1,000 river miles (in the Cumberland and Tennessee
mainstem rivers alone) from which they were historically known due to a
variety of threats, including impoundments, mining, poor water quality,
excessive sedimentation, and environmental contaminants.
Peer review and public comment. We sought comments from independent
specialists to ensure that our determination is based on scientifically
sound data, assumptions, and analyses. We invited these peer reviewers
to comment on our listing proposal. We also considered all comments and
information we received during the comment period.
Previous Federal Actions
We proposed listing the fluted kidneyshell and slabside
pearlymussel as endangered under the Act with critical habitat on
October 4, 2012 (77 FR 60804). For a complete history of all Federal
actions related to these species, please refer to the October 4, 2012,
proposed listing and critical habitat rule. Elsewhere in today's
Federal Register, we designate critical habitat
[[Page 59270]]
for the fluted kidneyshell and slabside pearlymussel under the Act.
Background
Introduction
North American mussel fauna are more biologically diverse than
anywhere else in the world, and historically numbered around 300
species (Williams et al. 1993, p. 6). Mussels are in decline, however,
and in the past century have become more imperiled than any other group
of organisms (Williams et al. 2008, p. 55). Approximately 72 percent of
North America's mussel species are considered vulnerable to extinction
or possibly extinct (Williams et al. 1993, p. 6). Within North America,
the southeastern United States is the hot spot for mussel diversity.
Seventy-five percent of southeastern mussel species are in varying
degrees of rarity or possibly extinct (Neves et al. 1997, pp. 47-51).
The central reason for the decline of mussels is the modification and
destruction of their habitat, especially from dams, degraded water
quality, and sedimentation (Neves et al. 1997, p. 60). The fluted
kidneyshell and slabside pearlymussel, like many other southeastern
mussel species, have undergone considerable reductions in total range
and population density.
Most studies of the distribution and population status of the
fluted kidneyshell and slabside pearlymussel presented below were
conducted after the early 1960s. Gordon and Layzer (1989, entire),
Winston and Neves (1997, entire), and Parmalee and Bogan (1998, pp.
204-205) give most of the references for regional stream surveys. In
addition to these publications, we have obtained more current,
unpublished distribution and status information from State heritage
programs, State and Federal agency biologists, and other knowledgeable
individuals.
These two species are bivalve mussels and are endemic to the
Cumberland and Tennessee River drainages. The Cumberland River drainage
originates in southeastern Kentucky and flows southwest across
Tennessee before turning north and reentering Kentucky to empty into
the lower Ohio River. The Cumberland River drainage spans the
Appalachian Plateaus and Interior Low Plateaus Physiographic Provinces.
The Tennessee River originates in southwest Virginia and western North
Carolina, eastern Tennessee, and northern Georgia, and flows
southwesterly into northeastern Alabama, then flows across northern
Alabama before turning north and flowing through western Tennessee into
Kentucky and empties into the Ohio River. The greater Tennessee River
drainage spans five physiographic provinces, including the Blue Ridge,
Valley and Ridge, Appalachian Plateaus, Interior Low Plateaus, and
Coastal Plain.
Fluted Kidneyshell
Taxonomy and Species Description
The fluted kidneyshell, Ptychobranchus subtentum (Say, 1825), is in
the family Unionidae (Turgeon et al. 1998, p. 36). The following
description, biology, and life history of the fluted kidneyshell is
taken from Parmalee and Bogan (1998, pp. 204-205) and Williams et al.
(2008, pp. 627-629). The fluted kidneyshell is a relatively large
mussel that reaches about 13 centimeters (cm) (5 inches (in)) in
length. The shape of the shell is roughly oval elongate, and the solid,
relatively heavy valves (shells) are moderately inflated. A series of
flutings (parallel ridges or grooves) characterizes the posterior slope
of each valve. For a complete description of the species, please refer
to the October 4, 2012, proposed listing and critical habitat rule (77
FR 60804).
Habitat and Life History
Mussels generally live embedded in the bottom of rivers and other
bodies of water. They siphon water into their shells and across four
gills that are specialized for respiration, food collection, and
brooding larvae in females. Food items include detritus (disintegrated
organic debris), algae, diatoms, and bacteria (Strayer et al. 2004, pp.
430-431). Adults are filter feeders and generally orient themselves on
or near the substrate surface to take in food and oxygen from the water
column. Adult mussels also can obtain their food by deposit feeding,
pulling in food from the sediment and its interstitial (pore) water,
and pedal- (foot-) feeding directly from the sediment (Yeager et al.
1994, pp. 217-221; Vaughn and Hakenkamp 2001, pp. 1432-1438; Nichols et
al. 2005, pp. 90-93). Juveniles typically burrow completely beneath the
substrate surface and are deposit or pedal feeders. Until the
structures for filter feeding are more fully developed, food particles
that adhere to the foot while it is extended outside the shell and are
moved inside the shell for ingestion, until the structures for filter
feeding are more fully developed (Yeager et al. 1994, pp. 200-221;
Gatenby et al. 1996, p. 604).
Mussels tend to grow relatively rapidly for the first few years;
then growth slows appreciably after sexual maturity, when energy is
being diverted from growth to reproductive activities. Mussel longevity
varies tremendously among species (from 4 to 5 years to well over 100
years), but most species live 10 to 50 years (Haag and Rypel 2011, pp.
230-236). Relatively large, heavy-shelled riverine species tend to be
slower growing and have longer life spans. Reported longevity of the
fluted kidneyshell ranges from 26 to 55 years (Henley et al. 2002, p.
19; Davis and Layzer 2012, p. 92). Females can become sexually mature
at age 5 (Davis and Layzer 2012, p. 79).
The gametogenic cycle (annual cycle in the development of
reproductive cells or gametes) of fluted kidneyshell, like most
mussels, is probably regulated by annual temperature regimes (Davis and
Layzer, p. 90). Most mussels, including the fluted kidneyshell, have
separate sexes. Males expel sperm into the water column, which are
drawn in by females through their incurrent apertures. It has been
hypothesized that pheromones might trigger synchronous sperm release
among males, because all fertilization observed by fluted kidneyshell
females from the Clinch River occurred in fewer than 5 days (Davis and
Layzer 2012, p. 90). Fertilization takes place internally, and the
resulting zygotes develop into specialized larvae, termed glochidia,
inside the water tubes of the females' gills. The fluted kidneyshell,
along with other members of its genus, is unique in that the marsupial
portion of the outer gills (portion of a brooding female's gill which
holds embryos and glochidia) are folded in a curtain-like fashion. The
short (5 days or less) fertilization period of the fluted kidneyshell
is thought to occur sometime in late summer or early fall with the
glochidia overwintering. Davis and Layzer (2012, p. 90) observed embryo
development within the marsupium (brood pouch) at 4 weeks after
fertilization. The following spring or early summer, glochidia are
released as conglutinates, which are membrane-bound packets with scores
of glochidia within. Davis and Layzer (2012, p. 86) report an average
of 208 conglutinates and an average fecundity (total reproductive
output) of 247,000 glochidia per female. Davis and Layzer (2012, p. 92)
report a skewed adult sex ratio of 1.9 females per 1 male in the Clinch
River, in Tennessee, although the cause of the skewed ratio is unknown.
Using the observed sex ratio and percent of females that were gravid,
Davis and Layzer (2012, p. 92) hypothesized that some females go
through reproductive ``pausing'' periods to acquire the energy reserves
needed to produce gametes in subsequent years.
Glochidia must come into contact with specific host fish(es)
quickly in
[[Page 59271]]
order for their survival to be ensured. Without the proper species of
host fish, the glochidia will perish. Conglutinate masses often mimic
food items of glochidial fish hosts in order to attract and infest
potential host fishes. For example, fluted kidneyshell conglutinates
are shaped like black fly (Simuliidae) pupae and have an adhesive end
that sticks to silt-free stones on the stream bottom, with an
orientation that is also similar to that of blackfly pupae (Barnhart
and Roberts 1997, p. 17; Barnhart et al. 2008, p. 377; Williams et al.
2008, p. 628). Insects are common food items of many stream fishes,
including the fluted kidneyshell's host fishes, such as the barcheek
darter (Etheostoma obeyense), fantail darter (E. flabellare), rainbow
darter (E. caeruleum), redline darter (E. rufilineatum), bluebreast
darter (E. camurum), dusky darter (Percina sciera), and banded sculpin
(Cottus carolinae). These fishes are tricked into thinking that they
have an easy insect meal when in fact they have infected themselves
with parasitic mussel glochidia (Parmalee and Bogan 1998, p. 205; Davis
and Layzer 2012, p. 88).
After a few weeks parasitizing the host fish's gill, newly
metamorphosed juvenile mussels drop off to begin a free-living
existence on the stream bottom. Unless they drop off in suitable
habitat, they will perish. Thus, the complex life history of the fluted
kidneyshell and other mussels has many critical steps that may prevent
successful reproduction or recruitment of juveniles into existing
populations or both.
The fluted kidneyshell occurs in medium-sized creeks to large
rivers, inhabiting sand and gravel substrates in relatively shallow
riffles and shoals with moderate to swift current (Williams et al.
2008, p. 628). In comparison to some co-occurring species, the fluted
kidneyshell demonstrates strong habitat specificity by being associated
with faster flows, greater shear stress (force of water pressure and
velocity on the substrate), and low substrate embeddedness (Ostby 2005,
pp. 51, 142-3).
Historical Range and Distribution
The fluted kidneyshell is a Cumberlandian Region mussel, meaning it
is restricted to the Cumberland (in Kentucky and Tennessee) and
Tennessee (in Alabama, Kentucky, Tennessee, and Virginia) River
systems. Historically, this species occurred in the Cumberland River
mainstem from below Cumberland Falls in southeastern Kentucky
downstream through the Tennessee portion of the river to the vicinity
of the Kentucky-Tennessee State line. In the Tennessee River mainstem,
it occurred from eastern to western Tennessee. The fluted kidneyshell's
known historical and current occurrences, by water body and county, are
shown in Table 1 below (data collected from Gordon and Layzer 1989,
entire; Winston and Neves 1997, entire; Parmalee and Bogan 1998, pp.
204-205; Layzer and Scott 2006, p. 481).
Table 1--Known Historical (Prior to 1980) and Current Occurrences for the Fluted Kidneyshell
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Water body Drainage County State Historical or current
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Cumberland River.............. Cumberland....... McCreary, KY Historical.
Pulaski, Russell.
Cumberland River.............. Cumberland....... Stewart.......... TN Historical.
Middle Fork Rockcastle River.. Cumberland....... Jackson.......... KY Historical and Current
Horse Lick Creek.............. Cumberland....... Jackson, KY Historical and Current.
Rockcastle.
Rockcastle River.............. Cumberland....... Laurel, Pulaski, KY Historical.
Rockcastle.
Buck Creek.................... Cumberland....... Pulaski.......... KY Historical and Current.
Big South Fork Cumberland Cumberland....... McCreary, Pulaski KY Historical and Current.
River.
Big South Fork Cumberland Cumberland....... Fentress, Morgan, TN Historical and Current.
River. Scott.
Rock Creek.................... Cumberland....... McCreary......... KY Historical and Current.
Little South Fork Cumberland Cumberland....... McCreary, Wayne.. KY Historical and Current.
River.
Kennedy Creek................. Cumberland....... Wayne............ KY Historical.
Pitman Creek.................. Cumberland....... Pulaski.......... KY Historical.
Otter Creek................... Cumberland....... Wayne............ KY Historical.
Wolf River.................... Cumberland....... Fentress, Pickett TN Historical and Current.
Town Branch................... Cumberland....... Pickett.......... TN Historical and Current.
Obey River.................... Cumberland....... ?................ TN Historical.
West Fork Obey River.......... Cumberland....... Overton.......... TN Historical and Current.
Caney Fork River.............. Cumberland....... ?................ TN Historical.
South Harpeth River........... Cumberland....... Davidson......... TN Historical.
West Fork Red River........... Cumberland....... Todd............. KY Historical.
South Fork Powell River....... Tennessee........ Wise............. VA Historical.
Powell River.................. Tennessee........ Claiborne, TN Historical and Current.
Hancock.
Powell River.................. Tennessee........ Campbell, Union.. TN Historical.
Powell River.................. Tennessee........ Lee.............. VA Historical and Current.
Indian Creek.................. Tennessee........ Tazewell......... VA Historical and Current.
Clinch River.................. Tennessee........ Hancock.......... TN Historical and Current.
Clinch River.................. Tennessee........ Anderson, TN Historical.
Claiborne,
Grainger, Roane,
Union.
Clinch River.................. Tennessee........ Russell, Scott, VA Historical and Current.
Tazewell, Wise.
Little River.................. Tennessee........ Russell, Tazewell VA Historical and Current.
Copper Creek.................. Tennessee........ Scott............ VA Historical and Current.
North Fork Holston River...... Tennessee........ Hawkins, Sullivan TN Historical.
North Fork Holston River...... Tennessee........ Bland, Scott, VA Historical and Current.
Smyth,
Washington.
Big Moccasin Creek............ Tennessee........ Scott............ VA Historical and Current.
Middle Fork Holston River..... Tennessee........ Smyth............ VA Historical and Current.
South Fork Holston River...... Tennessee........ Sullivan......... TN Historical.
South Fork Holston River...... Tennessee........ Washington....... VA Historical.
Holston River................. Tennessee........ Grainger, TN Historical.
Hamblen,
Jefferson, Knox.
French Broad River............ Tennessee........ ?................ TN Historical.
Tennessee River............... Tennessee........ Colbert, Jackson, AL Historical.
Lauderdale.
Tennessee River............... Tennessee........ Decatur, Knox, TN Historical.
Meigs, Rhea.
Nolichucky River.............. Tennessee........ Greene........... TN Historical and Current.
[[Page 59272]]
West Prong Little Pigeon River Tennessee........ Sevier........... TN Historical.
Tellico River................. Tennessee........ Monroe........... TN Historical.
Little Tennessee River........ Tennessee........ Monroe........... TN Historical.
Hiwassee River................ Tennessee........ Polk............. TN Historical.
Flint River................... Tennessee........ Madison.......... AL Historical.
Limestone Creek............... Tennessee........ Limestone........ AL Historical.
Elk River..................... Tennessee........ Limestone........ AL Historical.
Elk River..................... Tennessee........ Coffee, Franklin. TN Historical.
Boiling Fork Creek............ Tennessee........ Franklin......... TN Historical.
Shoal Creek................... Tennessee........ Lauderdale, AL Historical.
Limestone.
Duck River.................... Tennessee........ Bedford, TN Historical and Current.
Marshall, Maury.
Buffalo River................. Tennessee........ Lewis............ TN Historical.
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Note: A ? represents a lack of specific locational information in the museum and literature record.
Prior to 1980, the fluted kidneyshell was fairly widespread and
common in many Cumberlandian Region streams based on collections in
museums and from the literature record. The extirpation of this species
from numerous streams within its historical range indicates that
substantial population losses and range reductions have occurred.
Current Range and Distribution
In this document, populations of the fluted kidneyshell are
generally considered extant (current) if live individuals or fresh dead
specimens (individuals that are deceased, but still have flesh attached
to the shell) have been collected since circa 1980. This criterion was
chosen because a large number of collections were conducted in the
1980s in the Cumberland and Tennessee River systems, and due to the
longevity of this species (26-55 years), they are still thought to
occur in these areas. Where two or more stream populations occur
contiguously with no barriers, such as impoundments or long reaches of
unoccupied habitat, they are considered single population segments or
clusters. Multi-stream population segments include the Wolf River and
its tributary Town Branch in the Cumberland River system, and Clinch
River and Copper Creek (but not the other two upper Clinch tributaries,
Indian Creek and Little River) in the Tennessee River system. Based on
these criteria, we consider 17 of 40 populations of fluted kidneyshell
to be extant. Therefore, the fluted kidneyshell has been eliminated
from more than 50 percent of streams from which it was historically
known.
Several populations considered extant at the time this species was
elevated to candidate status in 1999 (e.g., Rockcastle River, Kennedy
Creek) are now considered to be extirpated. In addition, the population
in the upper North Fork Holston River, although still large, has
declined substantially since circa 2000. The North Fork Holston River
population is predominately composed of large individuals, unlike the
Clinch River population, which is skewed towards smaller size classes
(Ostby et al. 2010, pp. 7, 22-24). These differences in population
characteristics are a clear indication that recruitment in the Clinch
River population is more observable than the population in the North
Fork Holston River.
Resource managers have been making attempts to reintroduce the
fluted kidneyshell into historical habitat over the past decade. In
Tennessee, thousands of individuals of the species have been
translocated (transferred from one location to another) from the Clinch
River into three sites in the upper Duck River and into two sites in
the Nolichucky River by Tennessee Wildlife Resource Agency (TWRA)
biologists (Hubbs 2011, unpubl. data). In 2010, six individuals were
collected during a quantitative survey at Lillard's Mill in the Duck
River, confirming some level of survival and persistence of the
reintroduced population (Hubbs et al. 2011, p. 18). The individuals
collected appeared in good condition and had grown noticeably since
their release (as evidenced by external shell marks) (Hubbs 2011,
unpubl. data). Evidence that the reintroduced population of fluted
kidneyshell was recruiting was documented in 2012, when a young
unmarked sub-adult individual was found in a muskrat midden (pile or
mound of shells) near Lillard's Mill in the Duck River (Hubbs 2012,
pers. comm.). In 2008, the Kentucky Department of Fish and Wildlife
Resources (KDFWR) translocated 144 individuals from the Clinch River
into the Big South Fork of the Cumberland River, Kentucky (Hubbs 2011,
unpubl. data). Both reintroduction sites in the Nolichucky River have
retained ``large numbers of live individuals'' (Hubbs 2012, pers.
comm.). It is not known if the Big South Fork reintroductions have been
successful. Approximately 691 adult individuals of the species have
been translocated from the Clinch River, Tennessee, into the Little
Tennessee River bypass reach below Calderwood Dam, Tennessee (Moles
2012, pers. comm.). The Virginia Department of Game and Inland
Fisheries (VDGIF) reintroduced 58 adults into Indian Creek, a tributary
to the Clinch River, using Clinch River stock. They have also
propagated and released 562 juveniles into the North Fork Holston River
(Duncan 2012, pers. comm.).
The extant fluted kidneyshell populations (including the
potentially reintroduced populations) in the Cumberlandian Region
generally represent small, isolated occurrences. The only population of
the fluted kidneyshell known to be large, stable, and viable is in the
Clinch River, but it is in a relatively short reach of river primarily
in the vicinity of the Tennessee-Virginia State line. Jones (2012,
unpub. data) estimates 500,000 to 1,000,000 individuals occur in the
Clinch River from just a 32-river-kilometer (rkm) (20-river-mile (rmi))
reach (rkm 309 to 277 (rmi 172 to 192)). Live adults and juveniles have
been observed over the past 10 years in shoal habitats in the upper
Clinch River, Virginia, particularly at and above Cleveland Islands,
and many more fresh dead shells have been collected in muskrat middens
in this reach. Eckert and Pinder (2010, pp. 23-30) collected 18
individuals in quantitative samples and 11 individuals in semi-
quantitative samples in the Clinch River at Cleveland Island in 2008,
and 15 individuals in quantitative samples and 62 individuals in semi-
quantitative
[[Page 59273]]
samples in the Clinch River at Cleveland Island in 2002. Ostby and
Angermeier (2011, entire) found two live individuals in the Little
River (tributary to Clinch River). Henley et al. (1999, pp. 20, 22)
collected live individuals at 6 of 25 sites surveyed in the Middle Fork
Holston River in 1997 and 1998. The fluted kidneyshell was found in
Copper Creek between creek rkm 2 and 31 (rmi 1 and 19) (Hanlon et al.
2009, pp. 15-17). Petty et al. (2006, pp. 4, 36) found the species
between Copper Creek rkm 24 and 31 (rmi 15 and 19), and reported
evidence of reproduction and recruitment of the species at these
locations. In 2008-09, 35 live individuals were found at 5 of 21 sites
sampled in the Powell River, in both Tennessee and Virginia, and there
was some indication of relatively recent recruitment (Johnson et al.
2012, p. 96). Ostby et al. (2010, pp. 16-20) observed 772 individuals
during qualitative surveys and 10 individuals in quantitative surveys
in the North Fork Holston River, Virginia.
Live fluted kidneyshell have not been collected in the Middle Fork
Rockcastle River since the mid-1980s (Layzer and Anderson 1992, p. 64).
Haag and Warren (2004, p. 16) collected only fresh dead shell material
in Horse Lick Creek, and reported that a small, extremely vulnerable
population of the fluted kidneyshell may exist there, but at very low
levels that they were not able to detect. Warren and Haag (2005, pp.
1384, 1388-1396) reported a vast reduction of the once sizable Little
South Fork population since the late 1980s. Live fluted kidneyshell
have not been collected in the Big South Fork since the mid-1980s
(Ahlstedt et al. 2003-2004, p. 65). In 2010, two individuals were found
in Buck Creek and collected for future propagation efforts (McGregor
2010, unpub. data). Live fluted kidneyshell have not been collected in
Rock Creek since 1988 (Layzer and Anderson 1992, p. 68). Layzer and
Anderson (1992, p. 22) collected fluted kidneyshell at two sites in the
West Fork Obey River. A small but recruiting population occurs in the
Wolf River, Tennessee, based on 2005-2006 sampling (Moles et al. 2007,
p. 79). This may be the best population remaining in the entire
Cumberland River system, where most populations are very restricted in
range and are highly imperiled. Given its longevity, small populations
of this long-lived species may persist for decades despite total
recruitment failure. Given the reports presented above, at least five
of the extant populations may be functionally extirpated (e.g., Horse
Lick Creek, Middle Fork Rockcastle River, Little South Fork Cumberland
River, Rock Creek, West Fork Obey River).
Population Estimates and Status
Extirpated from both the Cumberland and Tennessee River mainstems,
the fluted kidneyshell has been eliminated from approximately 50
percent of the total number of streams from which it was historically
known. Population size data gathered during the past decade or two
indicate that the fluted kidneyshell is rare in nearly all extant
populations, the Clinch River being a notable exception. The fluted
kidneyshell is particularly imperiled in Kentucky. Haag and Warren
(2004, p. 16) reported that a small, extremely vulnerable population of
the fluted kidneyshell may exist in Horse Lick Creek but at extremely
low levels that they were not able to detect. They only collected fresh
dead shell material in Horse Lick Creek. The vast reduction of the once
sizable Little South Fork population since the late 1980s (Warren and
Haag 2005, pp. 1384, 1388-1396) and the tenuous status of the other
Cumberland River system populations put the species at risk of total
extirpation from that Cumberland River system. In addition, the
populations in the Powell River (post-1980) and the Middle Fork (post-
1995) and upper North Fork (post-2000) Holston Rivers in Virginia have
declined in recent years based according to recent survey efforts
(Henley et al. 1999, p. 23; Ahlstedt et al. 2005, p. 9; Jones and Neves
2007, p. 477; Johnson et al. 2012, pp. 94-96). Populations of the
fluted kidneyshell remain locally abundant in certain reaches of the
North Fork Holston River but are reduced in overall range within the
river (Ostby and Neves 2005, 2006a, and 2006b, entire; Dinkins 2010a,
p. 3-1). Declines in mussel community abundance in the North Fork
Holston River have been in the form of several die-offs. The cause for
the observed die-offs is unknown (Jones and Neves 2007, p. 479), but
they are likely related to agricultural impacts (Hanlon et al. 2009, p.
11).
In summary, the fluted kidneyshell has been eliminated from more
than 50 percent of the total number of streams from which it was
historically known. Populations in Buck Creek, Little South Fork, Horse
Lick Creek, Powell River, and North Fork Holston River have clearly
declined over the past two decades. Based on recent information, the
overall population status of the fluted kidneyshell rangewide is
declining. A few populations are considered to be viable (e.g., Wolf,
Clinch, Little, North Fork Holston Rivers). However, all other
populations are of questionable viability, with some on the verge of
extirpation (e.g., Horse Lick and Rock Creeks). Newly reintroduced
populations will hopefully begin to reverse the overall downward trend
of this species.
The fluted kidneyshell was considered a species of special concern
by Williams et al. (1993, p. 14), but two decades later is now
considered endangered in a reassessment of the North American mussel
fauna by the Endangered Species Committee of the American Fisheries
Society (Butler 2012, pers. comm.). Further, the fluted kidneyshell is
listed as a species of Greatest Conservation Need (GCN) in the
Kentucky, Tennessee, and Virginia State Wildlife Action Plans (KDFWR
2005; TWRA 2005; VDGIF 2005).
Slabside Pearlymussel
Taxonomy and Species Description
The taxonomic status of the slabside pearlymussel (family
Unionidae) as a distinct species is undisputed within the scientific
community. The species is recognized as Lexingtonia dolabelloides (I.
Lea, 1840) in the ``Common and Scientific Names of Aquatic
Invertebrates from the United States and Canada: Mollusks, Second
Edition'' (Turgeon et al. 1998, p. 35). However, there are currently
differing opinions on the appropriate genus to use for the species.
Genetic analyses by Bogan et al. (unpublished data), as cited by
Williams et al. (2008, p. 584), suggest that the type species of
Lexingtonia, Unio subplana Conrad, 1837, is synonymous with Fusconaia
masoni (Conrad, 1834). Lexingtonia is therefore a junior synonym of
Fusconaia (Williams 2011, pers. comm.). Analyses by Campbell et al.
(2005, pp. 141, 143, 147) and Campbell and Lydeard (2012a, pp. 3-6, 9;
2012b, pp. 25-27, 30, 34) suggest that ``Lexingtonia'' dolabelloides,
``Fusconaia'' barnesiana, and ``Pleurobema'' gibberum do not correspond
to their currently assigned genera but form a closely related group.
Williams et al. (2008, pp. 584-593) and Campbell and Lydeard (2012b,
pp. 30, 34) picked the next available genus name for dolabelloides,
which appears to be Pleuronaia (Frierson 1927). Based on this latest
information, we currently consider Pleuronaia to be the most
appropriate generic name for the slabside pearlymussel.
The following description, biology, and life history of the
slabside pearlymussel is taken from data summarized in Parmalee and
Bogan (1998, pp. 150-152). The slabside pearlymussel is a moderately
sized mussel that reaches about 9 cm (3.5 in)
[[Page 59274]]
in length. The shape of the shell is subtriangular, and the very solid,
heavy valves are moderately inflated. For a complete description of the
species, please refer to the October 4, 2012, proposed listing and
critical habitat rule (77 FR 60804).
Habitat and Life History
General life-history information for the slabside pearlymussel is
similar to that given for the fluted kidneyshell above. Samples from
approximately 150 shells of the slabside pearlymussel from the North
Fork Holston River were thin-sectioned for age determination. The
maximum age exceeded 40 years (Grobler et al. 2005, p. 65).
The slabside pearlymussel utilizes all four gills as a marsupium
for its glochidia. It is thought to have a spring or early summer
fertilization period with the glochidia being released during the late
summer in the form of conglutinates. Slabside pearlymussel
conglutinates have not been described. The slabside pearlymussel's host
fishes include 11 species of minnows (popeye shiner, Notropis ariommus;
rosyface shiner, N. rubellus; saffron shiner, N. rubricroceus; silver
shiner, N. photogenis; telescope shiner, N. telescopus; Tennessee
shiner, N. leuciodus; whitetail shiner, Cyprinella galactura; striped
shiner, Luxilus chrysocephalus; warpaint shiner, L. coccogenis; white
shiner, L. albeolus; and eastern blacknose dace, Rhinichthys atratulus)
(Kitchel 1985 and Neves 1991 in Parmalee and Bogan 1998, pp. 150-152;
Jones and Neves 2002, pp. 18-20).
The slabside pearlymussel is primarily a large creek to large river
species, inhabiting sand, fine gravel, and cobble substrates in
relatively shallow riffles and shoals with moderate current (Parmalee
and Bogan 1998, p. 152; Williams et al. 2008, p. 590). This species
requires flowing, well-oxygenated waters to thrive.
Historical Range and Distribution
Historically, the slabside pearlymussel occurred in the lower
Cumberland River mainstem from the vicinity of the Kentucky State line
downstream to the Caney Fork River, Tennessee, and in the Tennessee
River mainstem from eastern Tennessee to western Tennessee. The
slabside pearlymussel's known historical and current occurrences, by
water body and county, are shown in Table 2 below (data from Gordon and
Layzer 1989, entire; Winston and Neves 1997, entire; Parmalee and Bogan
1998, pp. 150-152).
Table 2--Known Historical (Prior to 1980) and Current Occurrences for the Slabside Pearlymussel
----------------------------------------------------------------------------------------------------------------
Historical or
Water body Drainage County State current
----------------------------------------------------------------------------------------------------------------
Cumberland River................ Cumberland........ Davidson, Smith... TN................ Historical.
Rock Creek...................... Cumberland........ McCreary.......... KY................ Historical.
Caney Fork River................ Cumberland........ ?................. TN................ Historical.
Red River....................... Cumberland........ Logan............. KY................ Historical.
Red River....................... Cumberland........ ?................. TN................ Historical.
South Fork Powell River......... Tennessee......... Wise.............. VA................ Historical.
Powell River.................... Tennessee......... Claiborne......... TN................ Historical.
Powell River.................... Tennessee......... Hancock........... TN................ Historical and
Current.
Powell River.................... Tennessee......... Lee............... VA................ Historical and
Current.
Puckell Creek................... Tennessee......... Lee............... VA................ Historical.
Clinch River.................... Tennessee......... Hancock........... TN................ Historical and
Current.
Clinch River.................... Tennessee......... Anderson, TN................ Historical.
Campbell,
Claiborne, Knox.
Clinch River.................... Tennessee......... Russell, Scott, VA................ Historical and
Tazewell, Wise. Current.
North Fork Holston River........ Tennessee......... Hawkins, Sullivan. TN................ Historical.
North Fork Holston River........ Tennessee......... Bland, Scott, VA................ Historical and
Smyth, Washington. Current.
Big Moccasin Creek.............. Tennessee......... Russell, Scott.... VA................ Historical and
Current.
Middle Fork Holston River....... Tennessee......... Smyth, Washington, VA................ Historical and
Wythe. Current.
South Fork Holston River........ Tennessee......... Sullivan.......... TN................ Historical.
Holston River................... Tennessee......... ?................. TN................ Historical.
French Broad River.............. Tennessee......... Sevier............ TN................ Historical.
Tennessee River................. Tennessee......... Colbert, Jackson, AL................ Historical.
Lauderdale.
Tennessee River................. Tennessee......... Hamilton, Hardin, TN................ Historical.
Knox, Meigs, Rhea.
Nolichucky River................ Tennessee......... Cocke, Greene, TN................ Historical and
Hamblen. Current.
West Prong Little Pigeon River.. Tennessee......... Sevier............ TN................ Historical.
Tellico River................... Tennessee......... Monroe............ TN................ Historical.
Little Tennessee River.......... Tennessee......... Monroe............ TN................ Historical.
Hiwassee River.................. Tennessee......... Polk.............. TN................ Historical and
Current.
Spring Creek.................... Tennessee......... Polk.............. TN................ Historical.
Sequatchie River................ Tennessee......... Sequatchie........ TN................ Historical and
Current.
Crow Creek...................... Tennessee......... Jackson........... AL................ Historical.
Larkin Fork..................... Tennessee......... Jackson........... AL................ Historical and
Current.
Estill Fork..................... Tennessee......... Jackson........... AL................ Historical and
Current.
Hurricane Creek................. Tennessee......... Jackson........... AL................ Historical and
Current.
Paint Rock River................ Tennessee......... Jackson, Madison, AL................ Historical and
Marshall. Current.
Flint River..................... Tennessee......... Madison........... AL................ Historical.
Flint Creek..................... Tennessee......... Morgan............ AL................ Historical.
Limestone Creek................. Tennessee......... Limestone......... AL................ Historical.
Elk River....................... Tennessee......... Limestone......... AL................ Historical and
Current.
Elk River....................... Tennessee......... Lincoln........... TN................ Historical and
Current.
Elk River....................... Tennessee......... Coffee, Franklin, TN................ Historical.
Moore.
Sugar Creek..................... Tennessee......... Limestone......... AL................ Historical.
Bear Creek...................... Tennessee......... Colbert........... AL................ Historical and
Current.
Bear Creek...................... Tennessee......... Tishomingo........ MS................ Historical and
Current.
[[Page 59275]]
Duck River...................... Tennessee......... Bedford, Hickman, TN................ Historical and
Marshall, Maury. Current.
Duck River...................... Tennessee......... Coffee............ TN................ Historical.
North Fork Creek................ Tennessee......... Bedford........... TN................ Historical.
Big Rock Creek.................. Tennessee......... Marshall.......... TN................ Historical.
Buffalo River................... Tennessee......... Humphreys, Perry.. TN................ Historical and
Current.
Buffalo River................... Tennessee......... Lewis............. TN................ Historical.
----------------------------------------------------------------------------------------------------------------
Note: A ? represents a lack of specific locational information in the museum and literature record.
Based on collections made in the early 1900s, the slabside
pearlymussel was historically fairly widespread and common in many
Cumberlandian Region streams. However, its decline in certain streams
may have begun before European colonization. The slabside pearlymussel
was considered rare by mussel experts as early as 1970 (Stansbery 1971,
p. 13), which represents the first attempt to compile such a list. The
extirpation of this species from numerous streams within its historical
range indicates that substantial population losses and range reductions
have occurred.
Current Range and Distribution
In this document, populations of the slabside pearlymussel, as for
the fluted kidneyshell, are generally considered extant (current) if
live individuals or fresh dead specimens have been collected since
circa 1980. This criterion was chosen because a large number of
collections were conducted in the 1980s in the Cumberland and Tennessee
River systems and due to the longevity of this species (approximately
40 years), they are still thought to occur in these areas.
Where two or more stream populations occur contiguously with no
absolute barriers (e.g., large impoundments) or long reaches of
unoccupied habitat, they are considered to represent a single
population segment. The Paint Rock River system (including Larkin Fork,
Estill Fork, and Hurricane Creek) is considered a single population
segment or cluster but it occurs only in the lower mile or so of the
three tributary streams. Accordingly, we consider 13 of 30 populations
of the slabside pearlymussel to be extant. The slabside pearlymussel
has been eliminated from more than 50 percent of streams from which it
was historically known.
The extant occurrences in the Tennessee River system represent 11
isolated populations. Population size data gathered during the past two
decades indicate that the slabside pearlymussel is rare (experienced
surveyors may find four or fewer specimens per site of occurrence) in
about half of its extant populations. Only a few individuals have been
found in the Powell River since 1988; therefore, this population is
considered extremely rare (Ahlstedt et al. 2005, p. 9). In 2009, four
individuals were collected in the Powell River (Johnson et al. 2010, p.
39). A single live individual was found in 2006 in Big Moccasin Creek,
Virginia (Ostby et al. 2006, p. 3). The slabside pearlymussel is
uncommon to rare in the Clinch River, with only a few individuals found
per given survey effort (Ahlstedt et al. 2005, p. 8). In 2002, Eckert
and Pinder (2010, pp. 23-30) observed 2 individuals in quantitative
samples and 13 individuals in semi-quantitative samples in the Clinch
River at Cleveland Island; 6 years later, they collected 1 individual
in quantitative samples and 5 individuals in semi-quantitative samples
at the same site. In 2005, approximately 20 individuals were found near
Harms Mill (one of five sites surveyed) in the Elk River, Tennessee,
and 13 individuals (at 2 of 5 survey sites, spanning approximately 48
rkm (30 rmi)) were found in 2008 (Howard 2009, pers. comm.; Tennessee
Valley Authority (TVA) 2009, p. 59). In 2002, one live individual was
found in the Hiwassee River (Ahlstedt 2003, p. 3). The slabside
pearlymussel was last found in the Sequatchie River 2 miles north of
Dunlap, Tennessee in 1980 (Hatcher and Ahlstedt 1982, p. 9). A small
population is limited to Bear Creek in Mississippi, the only occurrence
in that State (Jones 2012, pers. comm.). In 2009, TVA collected 9
individuals at one site in Bear Creek (TVA 2010, p. 69). This
population is recruiting, as evidenced by collection of the shell
remains of a fresh dead juvenile in 2011 (Johnson 2011, pers. comm.).
Given its longevity, small populations of this long-lived species may
persist for decades, long after total recruitment failure. The species
has undergone decline in the North and Middle Forks of the Holston
River (Jones and Neves 2005, pp. 8-9). This is especially true for the
North Fork, where the species has been nearly eliminated (Hanlon 2006,
unpub. data). The cause for the observed die-offs is unknown (Jones and
Neves 2007, p. 479). Ostby et al. (2010, pp. 16-20) observed eight
individuals in qualitative surveys at one site, but did not observe the
species in quantitative surveys in the Upper North Fork Holston River.
Slabside pearlymussels have declined at three of four survey sites on
the Middle Fork Holston River (Henley 2011, pers. comm.). A single
valve of a fresh dead specimen was found in the Nolichucky River in
2011 (Dinkins 2010b, p. 2-1). In 2011, TVA collected one living
individual in the Buffalo River (Wales 2012, pers. comm.).
The Duck and Paint Rock Rivers appear to have the best populations
remaining rangewide based on population size and the evidence of recent
recruitment. The slabside pearlymussel is found at numerous sites
throughout the Duck River, and is found at numerous sites within a 72-
rkm (45-rmi) reach of the Paint Rock River (Schilling and Williams
2002, p. 409; Ahlstedt et al. 2004, p. 84; Fobian et al. 2008, pp. 15-
16; Hubbs 2012, pers. obs.). The slabside pearlymussel was reported
present but rare at four of six sites sampled in the Duck River during
a 2010 quantitative survey (Hubbs et al. 2011, pp. 19-25).
Population Estimates and Status
Current status information for most of the 13 extant populations is
available from recent survey efforts (sometimes annually) and other
field studies. Comprehensive surveys have taken place in the Middle and
North Forks Holston River, Paint Rock River, and Duck River in the past
several years. Based on this information, the overall population of the
slabside pearlymussel appears to be declining rangewide, with
relatively good numbers and apparent viability in just two streams
(Duck and Paint Rock Rivers). Two of the four largest populations in
the mid-1990s have recently experienced drastic recent
[[Page 59276]]
declines (i.e., North and Middle Forks Holston Rivers), especially in
the North Fork. Most of the other populations are of questionable
viability and may be on the verge of extirpation (e.g., Powell and
Hiwassee Rivers; Big Moccasin Creek).
Populations of the slabside pearlymussel appear to be declining
rangewide and have been extirpated from more than 50 percent of the
streams from which the species was historically known to occur. The
slabside pearlymussel was considered threatened by Williams et al.
(1993, p. 13), but is now considered endangered in a reassessment of
the North American mussel fauna by the Endangered Species Committee of
the American Fisheries Society (Butler 2012, pers. comm.). Further, the
slabside pearlymussel is listed as a species of Greatest Conservation
Need (GCN) in the Alabama, Mississippi, Tennessee, and Virginia State
Wildlife Action Plans (Alabama Department of Conservation and Natural
Resources, Division of Wildlife and Freshwater Fisheries, 2005; KDFWR
2005; Mississippi Department of Wildlife, Fisheries and Parks 2005;
TWRA 2005; VDGIF 2005).
Summary of Comments and Recommendations
In the proposed rule published on October 4, 2012 (77 FR 60804), we
requested that all interested parties submit written comments on the
proposed rule to list the fluted kidneyshell and slabside pearlymussel
by December 3, 2012. We also contacted appropriate Federal and State
agencies, scientific experts and organizations, and other interested
parties and invited them to comment on the proposal. Newspaper notices
inviting general public comment were published in newspapers covering
all affected counties in Alabama, Kentucky, Mississippi, Tennessee, and
Virginia. During that comment period, we received one request for a
public hearing in Virginia. We subsequently reopened the public comment
period for the October 4, 2012, proposed rule; made available the draft
economic analysis for the proposed critical habitat designation; and
announced a public informational session and public hearing on the
proposal, which we held on May 14, 2013 (78 FR 25041; April 29, 2013).
During the two comment periods for the proposed rule, we received
seven comment letters in response to the proposed determination of
endangered species status for the fluted kidneyshell and slabside
pearlymussel: Two from peer reviewers, one from a Federal agency, and
four from organizations or individuals. We did not receive any comments
from State agencies. Four of the seven commenters supported the
proposed rule. All substantive information provided during the comment
period has either been incorporated directly into this final
determination or is addressed below.
Peer Reviewer Comments
In accordance with our peer review policy published on July 1, 1994
(59 FR 34270), we solicited expert opinions from eight knowledgeable
individuals with scientific expertise that included familiarity with
the two mussels and their habitats, biological needs, and threats. We
received responses from two of the peer reviewers.
We reviewed all comments we received from the peer reviewers for
substantive issues and new information regarding the listing of the two
mussels. The peer reviewers generally concurred with our conclusions
and provided additional information on taxonomic classification, life
history, current distribution, and threats. Peer reviewers provided
minor edits and comments related to the listing of these species, which
we incorporated into the final rule as appropriate. The substantive
comments we received from one peer reviewer on the critical habitat
designation are addressed in the final critical habitat rule published
elsewhere in today's Federal Register.
Federal Agency Comments
(1) Comment: The U.S. Department of Agriculture, Natural Resources
Conservation Service (NRCS) in Kentucky would like to explore
opportunities to focus conservation practices, including the Wildlife
Habitat Incentives Program (WHIP) and the Environmental Quality
Incentives Program, on water quality improvement and restoration in any
areas designated as critical habitat for the fluted kidneyshell and
other aquatic organisms.
Our Response: The Service concurs that Farm Bill practices
implemented by the NRCS can improve water quality and benefit rare
aquatic species. We will continue to work with NRCS to identify aquatic
habitats for rare aquatic species that would benefit from conservation
practices on private lands.
Public Comments
(2) Comment: Under the Multi-District Litigation (MDL) settlement
agreement, the Service has failed to preserve and consider the
``warranted but precluded'' finding for this listing decision. Further,
the Service did not request comments on its decision to exclude this
finding, and does not in the proposed rule request public comment on
whether a ``warranted but precluded'' finding might be appropriate. The
failure to preserve the ``warranted by precluded'' finding negates
important conservation mechanisms for the mussels by removing
incentives for State and private conservation actions designed to avoid
the need for listing.
Our Response: The United States Court of Appeals for the District
of Columbia Circuit has recently spoken to these issues. Safari Club
International moved to intervene in the MDL, arguing in part that the
settlement agreements, ``establish an illegal procedure--the
elimination of the Service's statutory authority to find that a
proposal to list a species is warranted but precluded by higher
priorities.'' On January 4, 2013, the United States Court of Appeals
for the District of Columbia Circuit affirmed the District Court's
holding that Safari Club International lacked standing to challenge
these agreements (see Safari Club v. Salazar, 704 F.3d 972 (D.C. Cir.
2013)). Among other things, the Court held that neither the Act nor the
implementing regulations require the Service to invite comment when it
makes a warranted-but-precluded finding. Responding to the concern that
the failure to preserve the ``warranted by precluded'' finding negates
important conservation mechanisms, the Court held there is nothing to
indicate that Congress intended the Act ``to allow [the Service] to
delay commencing the rulemaking process for any reason other than the
existence of pending or imminent proposals to list species subject to a
greater degree of threat [that] would make allocation of resources to
such a petition unwise.''
Further, even if additional time for conservation measures was a
permissible reason for delaying the rulemaking process, we do not
believe failure to preserve the ``warranted by precluded'' finding
negates important conservation mechanisms for the mussels by removing
incentives for State and private conservation actions designed to avoid
the need for listing. As we discussed in the proposed listing rule (77
FR 60804; see Previous Federal Actions), the fluted kidneyshell has
been a formal candidate for listing under the Act since 1999, and the
slabside pearlymussel has been a formal candidate for listing since
1984. The MDL settlement agreements now provide predictability for
stakeholders and local communities. Prior to the settlement agreements,
stakeholders were unsure when the Service might pursue a listing
determination on a candidate species. The settlements have
[[Page 59277]]
allowed the Service to establish and make available to the public a
multi-year schedule for listing determinations on our candidate
species. Stakeholders know in advance, in some cases years in advance,
when we will be reviewing these candidates to determine whether a
listing proposal is still warranted. The settlements have also served
to encourage proactive conservation efforts by landowners, industry
groups, local communities, and government agencies. Sometimes proactive
conservation efforts can make a listing under the Act no longer
necessary. Candidate conservation agreements with assurances (CCAAs)
can also be developed and permitted to provide regulatory assurances to
participating landowners in the event that listing is still warranted.
Conservation efforts developed by stakeholders may also be rolled into
habitat conservation plans that provide predictability and compliance
with the Act for landowners, industry groups, or local communities.
(3) Comment: The Service published a proposed rule that had not
undergone peer review, thereby not necessarily reflecting sound
science, as required by section 4 of the Act and as required under
section 515(b)(2)(A) of the Information Quality Act. Rather than
conducting peer review prior to publication of the proposed rule, which
would allow the public to view a fully scientifically vetted proposal,
the Service opted to conduct peer review contemporaneously with the
public comment period. Additionally, there is no indication that the
public will have an opportunity to review and comment on the rule as
informed by peer review, which is troubling due to the Service relying
on decades-old data (e.g., concluding a population to be extant if
found post-1980).
Our Response: In accordance with our peer review policy published
on July 1, 1994 (59 FR 34270), we solicited expert opinion from eight
knowledgeable individuals with scientific expertise that included
familiarity with the two mussels and their habitats, biological needs,
and threats. In keeping with our policy, we contacted these peer
reviewers when the proposed rule was published in the Federal Register.
We received responses from two of the peer reviewers. We posted all of
the comments we received on the October 4, 2012, proposed rule to list
the fluted kidneyshell and slabside pearlymussel as endangered under
the Act with critical habitat (77 FR 60804) on the Internet at http://www.regulations.gov under Docket No. FWS-R4-ES-2012-0004.
We reviewed all comments we received from the peer reviewers and
others for substantive issues and new information regarding the listing
of both mussels. The peer reviewers generally concurred with our
conclusions and provided additional information on taxonomic
classification, life history, current distribution, and threats. Peer
reviewers provided minor edits and comments related to the listing of
these species, which we incorporated into the final rule as
appropriate.
Further, section 515(b)(2)(A) of the Information Quality Act
requires that each Federal agency issue guidelines ensuring and
maximizing the quality, objectivity, utility, and integrity of
information (including statistical information) disseminated by the
agency. The Service's guidelines, which are updated as of June 2012,
are available on the Internet at: http://www.fws.gov/informationquality/topics/IQAguidelines-final82307.pdf.
(4) Comment: The proposed rule relies on questionable factual and
scientific bases by considering populations of the two species to be
``extant'' if specimens have been observed since 1980, a period of over
30 years. This notion appears scientifically untested and misguided
given the Service's conclusion that the species have been eliminated
from over 50 percent of their habitat. The Service's asserted basis for
relying on dated information is circular, and scientific
determinations, such as whether a species is extant or endangered,
should be based on current, empirical data that are measurable and
repeatable.
Our Response: We are required, by statute and regulation, to base
our determinations solely on the basis of the best scientific and
commercial data available. In this document, populations of the fluted
kidneyshell are generally considered extant (current) if live
individuals or fresh dead specimens have been collected since circa
1980. This criterion (circa 1980) was chosen because a large number of
mussel collections were conducted in the 1980s in the Cumberland and
Tennessee River systems; fewer collections were conducted post-1980.
Although many of these reaches have not been surveyed since the 1980s,
due to the reported longevity of these species (26-55 years; Henley et
al. 2002, p. 19; Davis and Layzer 2012, p. 92), it is likely they still
occur in those reaches.
Approximately 50 percent of the habitat for these species has been
eliminated, most of which is due to impoundment, and we have not
considered impounded river reaches to be ``extant'' populations.
(5) Comment: The preamble of the proposed rule relies in part on
climate change as a factor supporting the listing decision and relies
on unsubstantiated claims about the effects of climate change on the
species. Additionally, such attenuated assertions of endangerment could
be used to justify the listing of almost any species and do not
constitute scientific evidence of endangerment.
Our Response: There is a growing concern that climate change may
lead to increased frequency of severe storms and droughts (McLaughlin
et al. 2002, p. 6074; Cook et al. 2004, p. 1015; Golladay et al. 2004,
p. 504). Specific effects of climate change to mussels, their habitat,
and their fish hosts could include changes in stream temperature
regimes and changes in the timing and levels of precipitation, causing
more frequent and severe floods and droughts. The present conservation
status, complex life histories, and specific habitat requirements of
mussels suggest that they may be quite sensitive to the effects of
climate change (Hastie et al. 2003, p. 45).
Increases in temperature and reductions in flow can also lower
dissolved oxygen levels in interstitial habitats, a condition that can
be lethal to juveniles (Sparks and Strayer 1998, pp. 131-133). Even
small increases in temperature can cause reductions in the survival of
freshwater mussel glochidia and juveniles, and temperatures currently
encountered in the temperate United States during summers are close to
or above the upper thermal tolerances of early life stages of
freshwater mussels (Pandolfo et al. 2010, pp. 965, 967). Effects to
mussel populations from these environmental changes could include
reduced abundance and biomass, altered species composition, and reduced
host fish availability (Galbraith et al. 2010, pp. 1180-1182).
During high flows, flood scour can dislodge mussels, potentially
causing them to be injured, buried, swept into unsuitable habitats, or
stranded and perish when flood waters recede (Vannote and Minshall
1982, p. 4105; Tucker 1996, p. 435; Hastie et al. 2001, pp. 107-115;
Peterson et al. 2011, unpaginated). We have deleted several ``may''
statements regarding how climate change could impact freshwater
mussels. We have added in citations regarding studies on how increased
temperature impacts larval and juvenile mussels (see Factor E for a
more detailed discussion).
(6) Comment: The proposed rule sets forth an overbroad statement of
the types of activities that could constitute a ``take'' of these
species. For example,
[[Page 59278]]
the rule identifies, ``unauthorized modification of the channel,
substrate, temperature, or water flow of any stream or water body in
which these species are known to occur'' and ``unauthorized discharge
of chemicals or fill material into any waters in which the fluted
kidneyshell and slabside pearlymussel are known to occur.''
Additionally, the Service fails to include the key qualification that
an action must [italics added by commenter for emphasis] proximately
cause actual death or injury to a species in order to qualify as
``harm'' within the meaning of ``take.''
Our Response: Section 9 of the Act and our regulations prohibit the
take of endangered and threatened species, with certain exceptions.
Take is defined by the Act as to harass, harm, pursue, hunt, shoot,
wound, kill, trap, capture, or collect, or to attempt to engage in any
such conduct. Harm is defined in our regulations at 50 CFR 17.3 to
include significant habitat modification or degradation that results in
death or injury to listed species by significantly impairing essential
behavioral patterns, including breeding, feeding, or sheltering. Also
in our regulations at 50 CFR 17.3, harass is defined as intentional or
negligent actions that create the likelihood of injury to listed
species to such an extent as to significantly disrupt normal behavioral
patterns which include, but are not limited to, breeding, feeding or
sheltering.
Examples of chemical spills and their effects on mussels, including
the fluted kidneyshell, are provided in the Chemical Contaminants
section under the Factor E discussion below. Questions regarding
whether specific activities would constitute a violation of section 9
of the Act should be directed to the Ecological Services Field Office
in the State where the activity would take place.
Summary of Changes From Proposed Rule
As a result of the comments we received during the public comment
periods (see above), we made the following changes to this final
listing rule:
(1) We revised the description of the Tennessee River in the
introduction.
(2) We added life-history information to the fluted kidneyshell
background section.
(3) We updated the current status of the fluted kidneyshell to
reflect recent evidence of recruitment.
(4) We revised the taxonomy section for the slabside pearlymussel.
(5) We revised the current and historical occurrences for both the
fluted kidneyshell and slabside pearlymussel.
(6) We have deleted several ``may'' statements regarding how
climate change could impact freshwater mussels and added in citations
regarding studies on how increased temperature impacts larval and
juvenile mussels (see Factor E for a more detailed discussion).
We note here, however, that none of these changes affected our
determinations for these two species, and as proposed, in this rule we
are listing both the fluted kidneyshell and slabside pearlymussel as
endangered species.
Summary of Factors Affecting the Species
Section 4 of the Act, and its implementing regulations at 50 CFR
part 424, set forth the procedures for adding species to the Federal
Lists of Endangered and Threatened Wildlife and Plants. Under section
4(a)(1) of the Act, we may list a species based on any of the following
five factors: (A) The present or threatened destruction, modification,
or curtailment of its habitat or range; (B) overutilization for
commercial, recreational, scientific, or educational purposes; (C)
disease or predation; (D) the inadequacy of existing regulatory
mechanisms; and (E) other natural or manmade factors affecting its
continued existence. Listing actions may be warranted based on any of
the above factors, singly or in combination. Each of these factors is
discussed below.
Factor A. The Present or Threatened Destruction, Modification, or
Curtailment of Its Habitat or Range
The decline of the fluted kidneyshell and slabside pearlymussel in
the Cumberlandian Region and other mussel species in the eastern United
States is primarily the result of habitat loss and degradation. Chief
among the causes of decline are impoundments, gravel and coal mining,
sedimentation, water pollution, and stream channel alterations (Neves
1993, pp. 4-5; Williams et al. 1993, p. 7; Neves et al. 1997, pp. 60-
78).
Impoundments
Impoundments result in the dramatic modification of riffle and
shoal habitats and the resulting loss of mussel resources, especially
in larger rivers. Impoundment impacts are most profound in riffle and
shoal areas, which harbor the largest assemblages of mussel species,
including the fluted kidneyshell and slabside pearlymussel. Mussels are
relatively immobile and, therefore, require a stable substrate to
survive and reproduce, and are particularly susceptible to channel
instability (Neves et al. 1997, p. 23) and alteration in the dynamic
processes involved in maintaining stream stability. Dams interrupt most
of a river's ecological processes by modifying flood pulses;
controlling impounded water elevations; altering water flow, sediments,
nutrients, energy inputs, and outputs; increasing depth; decreasing
habitat heterogeneity; and decreasing bottom stability due to
subsequent sedimentation. In addition, dams can also seriously alter
downstream water quality and riverine habitat and negatively impact
tailwater mussel populations. These changes include thermal alterations
immediately below dams; changes in channel characteristics, habitat
availability, and flow regime; daily discharge fluctuations; increased
silt loads; and altered host fish communities. For these above-
mentioned reasons, the reproductive process of riverine mussels is
generally disrupted by impoundments, making them unable to successfully
reproduce and recruit under reservoir conditions. Coldwater releases
from large, non-navigational dams and scouring of the river bed from
highly fluctuating, turbulent tailwater flows have also been implicated
in the demise of mussel faunas.
The damming of rivers has been a major factor contributing to the
demise of mussels (Bogan 1993, p. 604). Dams eliminate or reduce river
flow within impounded areas, trap silts and cause sediment deposition,
alter water temperature and dissolved oxygen levels, change downstream
water flow and quality, affect normal flood patterns, and block
upstream and downstream movement of mussels and their host fishes
(Bogan 1993, p. 604; Vaughn and Taylor 1999, pp. 915-917; Watters 1999,
pp. 261-264; McAllister et al. 2000, p. iii; Marcinek et al. 2005, pp.
20-21). Below dams, mollusk declines are associated with changes and
fluctuation in flow regime, scouring and erosion, reduced dissolved
oxygen levels, reduced food availability, water temperature alteration,
and changes in resident fish assemblages (Williams et al. 1993, p. 7;
Neves et al. 1997, pp. 63-64; Watters 1999, pp. 261-264; Marcinek et
al. 2005, pp. 20-21; Moles and Layzer 2008, p. 220). Because rivers are
linear systems, these alterations can cause mussel declines for many
miles below the dam (Moles and Layzer 2008, p. 220; Vaughn and Taylor
1999, p. 916).
Population losses due to impoundments have probably contributed
more to the decline of the
[[Page 59279]]
fluted kidneyshell, slabside pearlymussel, and other Cumberlandian
Region mussels than has any other single factor. The majority of the
Cumberland and Tennessee River mainstems and many of their largest
tributaries are now impounded and, therefore, are unsuitable for
Cumberlandian Region mussels. For example, approximately 90 percent of
the 904-river-kilometer (rkm) (562-river-mile (rmi)) length of the
Cumberland River downstream of Cumberland Falls is either impounded
(three locks and dams and Wolf Creek Dam) or otherwise adversely
impacted by coldwater discharges from Wolf Creek Dam. Other major U.S.
Army Corps of Engineers (Corps) impoundments on Cumberland River
tributaries (e.g., Obey River, Caney Fork) have inundated over 161 rkm
(100 rmi) of riverine habitat for the fluted kidneyshell and the
slabside pearlymussel. Layzer et al. (1993, p. 68) reported that 37 of
the 60 mussel species present in the Caney Fork River pre-impoundment
have been extirpated. By 1971, approximately 3,700 rkm (2,300 rmi)
(about 20 percent) of the Tennessee River and its tributaries with
drainage areas of 65 square rkm (25 square rmi) or greater were
impounded by the TVA (TVA 1971, p. 5). The subsequent completion of
additional major impoundments on tributary streams (e.g., Duck River in
1976, Little Tennessee River in 1979) significantly increased the total
river kilometers impounded behind the 36 major dams in the Tennessee
River system.
Given projected human population increases and the need for
municipal water supply, other proposals for small impoundment
construction are likely in the future within the Cumberland and
Tennessee River systems.
Mining and Commercial Navigation
Instream gravel mining has been implicated in the destruction of
mussel populations. Negative impacts associated with gravel mining
include stream channel modifications (e.g., altered habitat, disrupted
flow patterns, sediment transport), water quality modifications (e.g.,
increased turbidity, reduced light penetration, increased temperature),
macroinvertebrate population changes (e.g., elimination, habitat
disruption, increased sedimentation), and changes in fish populations
(e.g., impacts to spawning and nursery habitat, food web disruptions)
(Kanehl and Lyons 1992, pp. 26-27).
Gravel mining activities negatively impact the habitat of the
fluted kidneyshell in Buck Creek, one of the few remaining populations
of this species in the entire Cumberland River system. Gravel mining
activities also negatively impact the habitat of the slabside
pearlymussel in the Powell and Elk Rivers in the Tennessee River
system.
Channel modification for commercial navigation has been shown to
increase flood heights (Belt 1975, p. 684), partly as a result of an
increase in stream bed slope (Hubbard et al. 1993, p. 137). Flood
events are exacerbated, conveying large quantities of sediment,
potentially with adsorbed contaminants, into streams. Channel
maintenance often results in increased turbidity and sedimentation that
often smothers mussels (Stansbery 1970, p. 10).
Heavy metal-rich drainage from coal mining and associated
sedimentation has adversely impacted historically diverse mussel faunas
in the upper Cumberland and Tennessee River system streams. Strip
mining continues to threaten mussel habitats in coal field drainages of
the Cumberland Plateau, including streams harboring small fluted
kidneyshell populations (e.g., Horse Lick Creek, Little South Fork,
Powell River, Indian Creek). Portions of the upper Tennessee River
system are also influenced by coal mining activities. In field studies,
Powell River mussel populations were inversely correlated with coal
fines in the substrate: Mussels were rare in areas with coal deposits
(Kitchel et al. 1981, p. 21). In addition, decreased filtration times
and increased movements were noted in laboratory-held mussels (Kitchel
et al. 1981, p. 25). A quantitative study in the Powell River
attributed a decline of federally listed mussels and the long-term
decrease in overall species composition, since about 1980, to general
stream degradation due primarily to coal mining activities in the
headwaters (Ahlstedt and Tuberville 1997, pp. 74-76). Numerous gray-
water and black-water spill events have been documented in the Powell
and Clinch River drainages over the past several years. The habitats of
fluted kidneyshell, slabside pearlymussel, and other mussels in the
Clinch and Powell Rivers are increasingly being threatened by coal
mining activities. Price (2011, p. VIII-3) indicates total dissolved
solids concentrations have continued to rise in the Powell and Clinch
Rivers, with rapid increases in the upper Powell River, where coal
mining is most prominent.
Oil and Natural Gas Development
Oil and natural gas resources are present in some of the watersheds
that are known or historically were known to support the fluted
kidneyshell and slabside pearlymussel, including the Clinch, Powell,
and Big South Fork Rivers. Exploration and extraction of these energy
resources has the potential to result in increased siltation, a changed
hydrograph (flow regime), and altered water quantity and quality even
at a distance from the mine or well field. Although oil and natural gas
extraction generally occurs away from the river, extensive road and
pipeline networks are required to construct and maintain wells and
transport the extracted resources. These road and pipeline networks
frequently cross or occur near tributaries, contributing sediment to
the receiving waterway. In addition, the construction and operation of
wells may result in the illegal discharge of chemical contaminants and
subsurface minerals.
Sedimentation
Sedimentation is one of the most significant pollution problems for
aquatic organisms (Waters 1995, pp. 2-3) and has been determined to be
a major factor in mussel declines (Ellis 1936, pp. 39-40). Sources of
silt and sediment include poorly designed and executed timber
harvesting operations and associated activities; complete clearing of
riparian vegetation for agricultural, silvicultural, or other purposes;
and those construction, mining, and other practices that allow exposed
earth to enter streams. Agricultural activities, specifically an
increase in cattle grazing and the resultant nutrient enrichment and
loss of riparian vegetation along the stream, are responsible for much
of the sediment (Fraley and Ahlstedt 2000, p. 193; Hanlon et al. 2009,
pp. 11-12).
Heavy sediment loads can destroy mussel habitat, resulting in a
corresponding shift in mussel fauna (Brim Box and Mossa 1999, p. 100).
Excessive sedimentation can lead to rapid changes in stream channel
position, channel shape, and bed elevation (Brim Box and Mossa 1999, p.
102). Sedimentation has also been shown to impair the filter feeding
ability of mussels, and high amounts of suspended sediments can dilute
their food source (Dennis 1984, p. 212). We further describe the
detrimental effects of sedimentation on these species under Factor E.
Other Natural or Manmade Factors Affecting Its Continued Existence,
below.
Chemical Contaminants
Chemical contaminants are ubiquitous throughout the environment and
are considered a major threat in the decline of mussel species (Richter
et al. 1997, p. 1081; Strayer et al. 2004, p. 436;
[[Page 59280]]
Wang et al. 2007a, p. 2029; Cope et al. 2008, p. 451). Chemicals enter
the environment through both point and nonpoint discharges, including
spills, stormwater infrastructure, industrial sources, municipal
effluents, and agricultural runoff. These sources contribute organic
compounds, heavy metals, pesticides, and a wide variety of newly
emerging contaminants to the aquatic environment. As a result, water
and sediment quality can be degraded to the extent that mussel habitats
and populations are adversely impacted. We further describe the
detrimental effects of chemicals on these species under Factor E. Other
Natural or Manmade Factors Affecting Its Continued Existence, below.
Other Stream Channel Alterations
Other stream channel alterations that can impact mussel habitats
include bridges, other road crossing structures, and activities that
lower water tables (withdrawals). Levine et al. (2003, pp. 116-117)
found that bridges built between 1950 and 1969 caused channel
constriction and channel destabilization, resulting in mussel declines
up to 300 meters (984 feet) downstream of road crossings. Culverts can
act as barriers to fish passage (Wheeler et al. 2005, p. 149),
particularly by increasing flow velocity (Warren and Pardew 1998, p.
637). Stream channels become destabilized when improperly designed
culverts or bridges change the morphology and interrupt the transport
of woody debris, substrate, and water (Wheeler et al. 2005, p. 152).
Water withdrawals for irrigation, municipal, and industrial water
supplies are an increasing concern. For example, U.S. water consumption
doubled from 1960 to 2000, and is likely to increase further (Naiman
and Turner 2000, p. 960). Therefore, we anticipate road crossings,
ground and surface water withdrawals, and potential stream dewatering
to be threats to the habitat of the fluted kidneyshell and slabside
pearlymussel.
Summary of Factor A
Habitat loss and degradation negatively impact the fluted
kidneyshell and slabside pearlymussel. Severe degradation from
impoundments, gravel and coal mining, oil and natural gas development,
sedimentation, chemical contaminants, and stream channel alterations
threaten the stream habitat and water quality on which these species
depend. Contaminants associated with coal mining (metals, other
dissolved solids), municipal effluents (bacteria, nutrients,
pharmaceuticals), and agriculture (fertilizers, pesticides, herbicides,
and animal waste) cause degradation of water quality and habitats
through increased acidity and conductivity, instream oxygen
deficiencies, excess nutrification, and excessive algal growths.
Furthermore, these threats faced by the fluted kidneyshell and slabside
pearlymussel are imminent, and occur throughout the range of both
species. Also, the threats are a result of ongoing projects expected to
continue indefinitely, therefore perpetuating these impacts. As a
result of the imminence of these threats, combined with the
vulnerability of the remaining small, isolated populations to
extirpation from natural and manmade threats, the present or threatened
destruction, modification, or curtailment of the habitat and range of
these species represents a threat to both the fluted kidneyshell and
slabside pearlymussel now and into the future.
Factor B. Overutilization for Commercial, Recreational, Scientific, or
Educational Purposes
The fluted kidneyshell and slabside pearlymussel are not
commercially valuable species, but may be increasingly sought by
collectors due to their increasing rarity. Although scientific
collecting is not thought to represent a significant threat, localized
populations could become impacted and possibly extirpated by
overcollecting, particularly if regulations governing collection
activity are not enforced. However, we do not consider overutilization
for commercial, recreational, scientific, or educational purposes to be
a threat to either species now or likely to become a threat in the
future.
Factor C. Disease or Predation
Little is known about diseases in mussels (Grizzle and Brunner
2007, p. 6). Several mussel die-offs have been documented during the
past 20 years across the United States (Neves 1987, pp. 8-11). Although
the ultimate cause is unknown, some researchers believe that disease
may be a factor. Warren and Haag (2005, p. 1394) hypothesized that
declines in the Little South Fork Cumberland River, Kentucky, mussel
fauna, including the once abundant fluted kidneyshell population, may
have been at least partially attributed to disease, but no definitive
cause has been determined. We have no specific documentation indicating
that disease poses a threat to slabside pearlymussel populations.
Juvenile and adult mussels are prey items for some invertebrate
predators and parasites (e.g., nematodes and mites) and are prey for a
few vertebrate species (e.g., raccoons, muskrats, otters, fish, and
turtles) (Hart and Fuller 1974, pp. 225-240). Mussel parasites include
water mites, trematodes, oligochaetes, leeches, copepods, bacteria, and
protozoa (Grizzle and Brunner 2007, p. 6). Generally, parasites are not
suspected of being a major limiting factor (Oesch 1984, p. 16);
however, Gangloff et al. (2008, pp. 28-30) found that reproductive
output and physiological condition were negatively correlated with mite
and trematodes abundance, respectively. Stressors that reduce fitness
may make mussels more susceptible to parasites (Butler 2007, p. 90).
Neves and Odum (1989, entire) determined that muskrat predation on
the fluted kidneyshell represents a localized threat by in the upper
North Fork Holston River in Virginia. They concluded that muskrat
predation could limit the recovery potential of endangered mussel
species or contribute to the local extirpation of already depleted
mussel populations. Although other mammals (e.g., raccoon, mink)
occasionally feed on mussels, the threat from these predators is not
considered to be significant. Predation does occur, but it is
considered to be a normal aspect of the species' population dynamics
and, therefore, not a threat to the slabside pearlymussel or fluted
kidneyshell at the species' level under current conditions.
In summary, there is little information on disease in mussels, and
disease is not currently considered to be a threat to the fluted
kidneyshell or slabside pearlymussel and is not likely to become so in
the future. Although predation does occur and impacts local
populations, we conclude that predation is not a threat to these
species as a whole or likely to become so in the future.
Factor D. The Inadequacy of Existing Regulatory Mechanisms
The objective of the Federal Water Pollution Control Act, commonly
referred to as the Clean Water Act (CWA) (33 U.S.C. 1251 et seq.), is
to restore and maintain the chemical, physical, and biological
integrity of the nation's waters by preventing point and nonpoint
pollution sources. The CWA has a stated goal that ``. . . wherever
attainable, an interim goal of water quality which provides for the
protection and propagation of fish, shellfish, and wildlife and
provides for recreation in and on the water be achieved by July 1,
1983.'' States are responsible for setting and implementing water
quality standards
[[Page 59281]]
that align with the requirements of the CWA.
Nonpoint source (NPS) pollution comes from many diffuse sources,
unlike pollution from industrial and sewage treatment plants. NPS
pollution is caused by rainfall or snowmelt moving over and through the
ground. As the runoff moves, it transports natural and human-made
pollutants to lakes, rivers, wetlands, coastal waters, and ground
waters. States report that NPS pollution is the leading remaining cause
of water quality problems. The effects of NPS pollutants on specific
waters vary and may not always be fully assessed. However, these
pollutants have harmful effects on fisheries and wildlife (http://water.epa.gov/polwaste/nps/whatis.cfm).
Sources of NPS pollution within the watersheds occupied by both
mussels include agriculture, clearing of riparian vegetation,
urbanization, road construction, and other practices that allow bare
earth to enter streams. The Service has no information concerning the
implementation of the CWA regarding NPS pollution specific to
protection of both mussels. However, insufficient implementation of the
CWA could become a threat to both mussel species if they continue to
decline in numbers.
The fluted kidneyshell and slabside pearlymussel continue to
decline due to the effects of habitat destruction, poor water quality,
contaminants, and other factors. However, there is no specific
information known about the sensitivity of these mussels to common
point source pollutants like industrial and municipal pollutants and
very little information on other freshwater mussels. Because there is
very little information known about water quality parameters necessary
to fully protect freshwater mussels, such as the fluted kidneyshell and
slabside pearlymussel, it is difficult to determine whether the CWA is
adequately addressing the habitat and water quality threats to these
species (see discussion under Factor A and Factor E). However, given
that a goal of the CWA is to establish water quality standards that
protect shellfish and given that documented declines of these mussel
species still continue due to poor water quality and other factors, we
take a conservative approach in favor of the species and conclude that
the CWA has been insufficient to significantly reduce or remove these
threats to the fluted kidneyshell and slabside pearlymussel.
Factor E. Other Natural or Manmade Factors Affecting Its Continued
Existence
Altered Temperature Regimes
Natural temperature regimes can be altered by impoundments, water
releases from dams, industrial and municipal effluents, and changes in
riparian habitat. Critical thermal limits for survival and normal
functioning of many mussel species are unknown. High temperatures can
reduce dissolved oxygen concentrations in the water, which slows
growth, reduces glycogen stores, impairs respiration, and may inhibit
reproduction (Hart and Fuller 1974, pp. 240-241). Low temperatures can
significantly delay or prevent metamorphosis (Watters and O'Dee 1999,
pp. 454-455). Water temperature increases have been documented to
shorten the period of glochidial encystment, reduce the speed in which
they turn upright, increase oxygen consumption, and slow burrowing and
movement responses (Hart and Fuller 1974, pp. 240-241; Bartsch et al.
2000, p. 237; Watters et al. 2001, p. 546; Schwalb and Pusch 2007, pp.
264-265). Several studies have documented the influence of temperature
on the timing of aspects of mussel reproduction (for example, Gray et
al. 2002, p. 156; Allen et al. 2007, p. 85; Steingraeber et al. 2007,
pp. 303-309). Peak glochidial releases are associated with water
temperature thresholds that can be thermal minimums or thermal
maximums, depending on the species (Watters and O'Dee 2000, p. 136).
Abnormal temperature changes may cause particular problems for mussels
whose reproductive cycles may be linked to fish reproductive cycles
(Young and Williams 1984, entire).
Chemical Contaminants
Chemical spills can be especially devastating to mussels because
they may result in exposure of a relatively immobile species to
extremely elevated contaminant concentrations that far exceed toxic
levels and any water quality standards that might be in effect. Some
notable spills that released large quantities of highly concentrated
chemicals resulting in mortality to mussels and host fish include a
kill on the Clinch River at Carbo, Virginia, from a power plant
alkaline fly ash pond spill in 1967, and a sulfuric acid spill in 1970
(Crossman et al. 1973, p. 6). In addition, approximately 18,000 mussels
of several species, including the fluted kidneyshell and 750
individuals from three endangered mussel species (tan riffleshell
(Epioblasma florentina walkeri (=E. walkeri)), purple bean (Villosa
perpurpurea), and rough rabbitsfoot (Quadrula cylindrica strigillata)),
were eliminated from the upper Clinch River near Cedar Bluff, Virginia,
in 1998, when an overturned tanker truck released approximately 6,100
liters (1,600 gallons) of a chemical used in rubber manufacturing
(Jones et al. 2001, p. 20; Schmerfeld 2006, p. 12). These are not the
only instances where chemical spills have resulted in the loss of high
numbers of mussels (Neves 1991, p. 252; Jones et al. 2001, p. 20; Brown
et al. 2005, p. 1457; Schmerfeld 2006, pp. 12-13), but are provided as
examples of the serious threat chemical spills pose to mussel species,
such as the fluted kidneyshell and slabside pearlymussel.
Cope et al. (2008, p. 451) evaluated the pathways of exposure to
environmental pollutants for all four mollusk life stages (free
glochidia, encysted glochidia, juveniles, and adults) and found that
each life stage has both common and unique characteristics that
contribute to observed differences in contaminant exposure and
sensitivity. Very little is known about the potential mechanisms and
consequences of waterborne toxicants on sperm viability. However,
Watters (2011) demonstrated that the spermatozeugmata (sperm ball)
produced and released by male mussels are sensitive to varying levels
of salinity. When exposed to high enough salinity levels, the
spermatozeugmata disassociate and can be rendered nonviable if they
disassociate prior to entering a female mussel. This may pose yet
another significant challenge for mussels to successfully fertilize
eggs and promote recruitment if exposed to elevated salinity or
conductivity levels in the ambient water column.
In the female mollusk, the marsupial region of the gill is thought
to be physiologically isolated from respiratory functions; this
isolation may provide some level of protection from contaminant
interference with a female's ability to achieve fertilization or brood
glochidia (Cope et al. 2008, p. 454). However, a major exception to
this hypothesis is with chemicals that act directly on the
neuroendocrine pathways controlling reproduction (see discussion
below). Nutritional and ionic exchange is possible between a brooding
female and her glochidia, providing a route for chemicals (accumulated
or waterborne) to disrupt biochemical and physiological pathways (such
as maternal calcium transport for construction of the glochidial
shell).
Juvenile mussels typically remain burrowed beneath the sediment
surface for 2 to 4 years. Residence beneath the
[[Page 59282]]
sediment surface necessitates deposit (pedal) feeding and a reliance on
interstitial (pore) water for dissolved oxygen (Watters 2007, p. 56).
The relative importance of juvenile fluted kidneyshell and slabside
pearlymussel exposure to contaminants in overlying surface water,
interstitial (pore) water, whole sediment, or food has not been
adequately assessed. Exposure to contaminants from each of these routes
varies with certain periods and environmental conditions (Cope et al.
2008, pp. 453, 457).
The primary routes of exposure to contaminants for adult fluted
kidneyshell and slabside pearlymussel are surface water, sediment,
interstitial (pore) water, and diet; adults can be exposed when either
partially or completely burrowed in the substrate (Cope et al. 2008, p.
453). Adult mussels have some ability to detect certain toxicants in
the water and close their valves to avoid exposure (Van Hassel and
Farris 2007, p. 6). Adult mussel toxicity and relative sensitivity
(exposure and uptake of toxicants) may be reduced at high rather than
at low toxicant concentrations because uptake is affected by the
prolonged or periodic toxicant avoidance responses (when the avoidance
behavior can no longer be sustained for physiological reasons) (Cope et
al. 2008, p. 454). Toxicity results based on low-level exposure of
adults are similar to estimates for glochidia and juveniles for some
toxicants (e.g., copper). The duration of any toxicant avoidance
response by an adult mussel is likely to be affected by several
variables, such as species, age, shell thickness and gape, properties
of the toxicant, and water temperature. There is a lack of information
on toxicant response(s) specific to adult mussels (including the fluted
kidneyshell and slabside pearlymussel), but results of tests using
glochidia and juveniles may be valuable for protecting adults (Cope et
al. 2008, p. 454).
Chronic exposure to lower concentrations of contaminants, more
likely to be found in aquatic environments, can also adversely affect
mussels and result in the decline of mussel species. Such
concentrations may not be immediately lethal, but over time, can result
in mortality, reduced filtration efficiency, reduced growth, decreased
reproduction, changes in enzyme activity, and behavioral changes to all
mussel life stages. Frequently, procedures that evaluate the `safe'
concentration of an environmental contaminant (e.g., national water
quality criteria) do not have data for mussel species or exclude data
that are available for mussels (March et al. 2007, pp. 2066-2067,
2073).
Current research is now focusing on the contaminant sensitivity of
mussel glochidia and newly released juvenile mussels (Goudreau et al.
1993, pp. 219-222; Jacobson et al. 1997, p. 2390; Valenti et al. 2005,
pp. 1244-1245; Valenti et al. 2006, pp. 2514-2517; March et al. 2007,
pp. 2068-2073; Wang et al. 2007b, pp. 2041-2046) and juveniles
(Augspurger et al. 2003, p. 2569; Bartsch et al. 2003, p. 2561; Mummert
et al. 2003, p. 2549; Valenti et al. 2005, pp. 1244-1245; Valenti et
al. 2006, pp. 2514-2517; March et al. 2007, pp. 2068-2073; Wang et al.
2007b, pp. 2041-2046; Wang et al. 2007c, pp. 2053-2055) to such
contaminants as ammonia, metals, chlorine, and pesticides.
One chemical that is particularly toxic to early life stages of
mussels is ammonia. Sources of ammonia include agriculture (animal
feedlots and nitrogenous fertilizers), municipal wastewater treatment
plants, and industrial waste (Augspurger et al. 2007, p. 2026), as well
as precipitation and natural processes (i.e., decomposition of organic
nitrogen) (Goudreau et al. 1993, p. 212; Hickey and Martin 1999, p. 44;
Augspurger et al. 2003, p. 2569; Newton 2003, p. 1243). Therefore,
ammonia is considered a limiting factor for survival and recovery of
some mussel species due to its ubiquity in aquatic environments and
high level of toxicity, and because the highest concentrations
typically occur within microhabitats inhabited by mussels (Augspurger
et al. 2003, p. 2574). In addition, studies have shown that ammonia
concentrations increase with increasing temperature and low flow
conditions (Cherry et al. 2005, p. 378; Cooper et al. 2005, p. 381).
Mussels are also affected by heavy metals (Keller and Zam 1991, p.
543) such as cadmium, chromium, copper, mercury, and zinc, which can
negatively affect biological processes such as growth, filtration
efficiency, enzyme activity, valve closure, and behavior (Keller and
Zam 1991, p. 543; Naimo 1995, pp. 351-355; Jacobson et al. 1997, p.
2390; Valenti et al. 2005, p. 1244). Heavy metals occur in industrial
and wastewater effluents and are often a result of atmospheric
deposition from industrial processes and incinerators. Glochidia and
juvenile mussels have recently been studied to determine the acute and
chronic toxicity of copper to these life stages (Wang et al. 2007b, pp.
2036-2047; Wang et al. 2007c, pp. 2048-2056). The chronic values
determined for copper for survival and growth of juveniles are below
the Environmental Protection Agency's (EPA's) 1996 chronic water
quality criterion for copper (Wang et al. 2007c, pp. 2052-2055). March
(2007, pp. 2066 and 2073) identified that copper water quality criteria
and modified State water quality standards may not be protective of
mussels.
Mercury is another heavy metal that has the potential to negatively
affect mussel populations, and it is receiving attention due to its
widespread distribution and potential to adversely impact the
environment. Mercury has been detected throughout aquatic environments
as a product of municipal and industrial waste and atmospheric
deposition from coal burning plants. Valenti et al. (2005, p. 1242)
determined that for rainbow mussel, Villosa iris, glochidia were more
sensitive to mercury than juvenile mussels, and that reduced growth in
juveniles is seen when observed concentrations are higher than EPA's
criteria for mercury. Based on these data, we believe that EPA's water
quality standards for mercury should be protective of juvenile mussels
and glochidia, except in cases of illegal dumping, permit violations,
or spills. However, impacts to mussels from mercury toxicity may be
occurring in some streams. According to the National Summary Data
reported by States to the EPA, 4,716 monitored waters do not meet EPA
standards for mercury in the United States (http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T, accessed June
28, 2012). Acute mercury toxicity was determined to be the cause of
extirpation of a diverse mussel fauna for a 112-rkm (70-rmi) portion of
the North Fork Holston River (Brown et al. 2005, pp. 1455-1457).
In addition to ammonia, agricultural sources of chemical
contaminants include two broad categories that have the potential to
adversely impact mussel species: nutrients and pesticides. Nutrients
(such as nitrogen and phosphorus) can impact streams when their
concentrations reach levels that cannot be assimilated, a condition
known as over-enrichment. Nutrient over-enrichment is primarily a
result of runoff from livestock farms, feedlots, and heavily fertilized
row crops (Peterjohn and Correll 1984, p. 1471). Over-enriched
conditions are exacerbated by low-flow conditions, such as those
experienced during typical summer-season flows. Bauer (1988, p. 244)
found that excessive nitrogen concentrations can be detrimental to the
adult pearl mussel (Margaritifera margaritifera), as was evident by the
positive linear relationship between mortality and nitrate
concentration. Also, a study of
[[Page 59283]]
mussel life span and size (Bauer 1992, p. 425) showed a negative
correlation between growth rate and eutrophication, and longevity was
reduced as the concentration of nitrates increased. Nutrient over-
enrichment can result in an increase in primary productivity, and the
subsequent respiration depletes dissolved oxygen levels. This may be
particularly detrimental to juvenile mussels, which inhabit the
interstitial spaces in the substrate, where lower dissolved oxygen
concentrations are more likely than on the sediment surface where
adults tend to live (Sparks and Strayer 1998, pp. 132-133).
Elevated concentrations of pesticide frequently occur in streams
due to runoff, overspray application to row crops, and lack of adequate
riparian buffers. The timing of agricultural pesticide applications and
the reproductive and early life stages of mussels often coincide in the
spring and summer, and thus impacts to mussels due to pesticides may be
increased (Bringolf et al. 2007a, p. 2094). Little is known regarding
the impact of currently used pesticides to mussels even though some
pesticides, such as glyphosate (e.g., RoundupTM), are used
globally. Recent studies tested the toxicity of glyphosate, its
formulations, and a surfactant (MON 0818) used in several glyphosate
formulations, to early life stages of the fatmucket (Lampsilis
siliquoidea) (Bringolf et al. 2007a, p. 2094). Studies conducted with
juvenile mussels and glochidia determined that the surfactant (MON
0818) was the most toxic of the compounds tested and that fatmucket
glochidia were the most sensitive of organisms tested to date (Bringolf
et al. 2007a, p. 2094). RoundupTM, technical grade
glyphosate isopropylamine salt, and isopropylamine were also acutely
toxic to juveniles and glochidia (Bringolf et al. 2007a, p. 2097). The
impacts of other pesticides including atrazine, chlorpyrifos, and
permethrin on glochidia and juvenile life stages have also recently
been studied (Bringolf et al. 2007b, p. 2101). One study determined
that chlorpyrifos was toxic to both fatmucket glochidia and juveniles
(Bringolf et al. 2007b, p. 2104). The above results indicate the
potential toxicity of commonly applied pesticides and the threat to
mussel species as a result of the widespread use of these pesticides.
All of these pesticides are commonly used throughout the range of the
fluted kidneyshell and slabside pearlymussel.
Pharmaceutical chemicals used in commonly consumed drugs are
increasingly found in surface waters downstream from municipal
effluents. A nationwide study sampling 139 stream sites in 30 States
detected the presence of numerous pharmaceuticals, hormones, and other
organic wastewater contaminants downstream from urban development and
livestock production areas (Kolpin et al. 2002, pp. 1208-1210).
Exposure to waterborne and, potentially to sediment, toxicant chemicals
that act directly on the neuroendocrine pathways controlling
reproduction can cause premature release of viable or nonviable
glochidia. For example, the active ingredient in many human
prescription anti-depressant drugs belonging to the class of selective
serotonin reuptake inhibitors may exert negative reproductive effects
on mussels because of their action on serotonin and other
neuroendocrine pathways (Cope et al. 2008, pp. 455). These waterborne
chemicals alter mussel behavior and influence successful attachment of
glochidia on fish hosts, and therefore, may have population-level
implications for the fluted kidneyshell and slabside pearlymussel. This
information indicates it is likely that chemical contaminants have
contributed to declining fluted kidneyshell and slabside pearlymussel
populations and will likely continue to be a threat to these species in
the future. These threats result from spills that are immediately
lethal to these species, as well as chronic contaminant exposure, which
results in death, reduced growth, or reduced reproduction of fluted
kidneyshell and slabside pearlymussel.
Sedimentation
Impacts resulting from sediments have been noted for many
components of aquatic communities. For example, sediments have been
shown to abrade or suffocate periphyton (organisms attached to
underwater surfaces); affect respiration, growth, reproductive success,
and behavior of aquatic insects and mussels; and affect fish growth,
survival, and reproduction (Waters 1995, pp. 173-175).
Increased turbidity from suspended sediment can reduce or eliminate
juvenile mussel recruitment (Negus 1966, p. 525; Box and Mossa 1999,
pp. 101-102). Many mussel species use visual cues to attract host
fishes; such a reproductive strategy depends on clear water for
success. For example, increased turbidity may impact the life cycle of
the southern sandshell, Hamiota australis, by reducing the chance that
a sight-feeding host fish will encounter the visual display of the
mussel's superconglutinate lure (Haag et al. 1995, p. 475; Blalock-
Herod et al. 2002, p. 1885). If the superconglutinate is not
encountered by a host within a short time period, the glochidia will
become nonviable (O'Brien and Brim Box 1999, p. 133). Also, evidence
suggests that conglutinates of the southern kidneyshell (another
species of Ptychobranchus, P. jonesi), once released from the female
mussel in an attempt to lure potential host fish, must adhere to hard
surfaces in order to be seen by its fish host. If the surface becomes
covered in fine sediments, the conglutinate cannot attach and is swept
away (Hartfield and Hartfield 1996, p. 373).
Population Fragmentation and Isolation
Population isolation prohibits the natural interchange of genetic
material between populations, and small population size reduces the
reservoir of genetic diversity within populations, which can lead to
inbreeding depression (Allendorf and Luikart 2007, pp. 117-146). Small,
isolated populations, therefore, are more susceptible to environmental
pressures, including habitat degradation and stochastic events, and
thus are the most susceptible to extinction (Primack 2008, pp. 151-
153). It is likely that some populations of the fluted kidneyshell and
slabside pearlymussel are below the effective population size
(Soul[eacute] 1980, pp. 162-164; Allendorf and Luikart 2007, pp. 147-
170) required to maintain long-term genetic and population viability.
The present distribution and status of the fluted kidneyshell in
the upper Cumberland River system in Kentucky may provide an excellent
example of the detrimental bottleneck effect resulting when a minimum
viable population size is not maintained. A once large population of
this species occurred throughout the upper Cumberland River mainstem
below Cumberland Falls and in several larger tributary systems. In this
region, there were no absolute barriers to genetic interchange among
its subpopulations (and those of its host fishes) that occurred in
various streams. With the completion of Wolf Creek Dam in the late
1960s, the mainstem population was soon extirpated, and the remaining
populations isolated by the filling of Cumberland Reservoir. Whereas
small, isolated, tributary populations of imperiled, short-lived
species (e.g., most fishes) would have died out within a decade or so
after impoundment, the long-lived fluted kidneyshell would potentially
take decades to expire post-impoundment. Without the level of genetic
interchange the species experienced historically (i.e., without the
reservoir barrier), isolated populations may be slowly
[[Page 59284]]
dying out. The fluted kidneyshell and slabside pearlymussel were
similarly isolated by the completion of multiple reservoirs in the
Tennessee River system. Even given the improbable absence of
anthropogenic impacts, we may lose smaller isolated populations of the
fluted kidneyshell and slabside pearlymussel to the devastating
consequences of below-threshold effective population size (the minimum
population size that is needed for the population to reproduce and
continue to be viable).
Random Catastrophic Events
The remaining populations of the fluted kidneyshell and slabside
pearlymussel are generally small and geographically isolated. The
patchy distribution pattern of populations in short river reaches makes
them much more susceptible to extirpation from single catastrophic
events, such as toxic chemical spills. Such a spill occurred in the
upper Clinch River in 1998, killing many fluted kidneyshell and
thousands of specimens of other mussel species, including three
federally listed species (Henley et al. 2002, entire; see Chemical
Contaminants section above). High levels of isolation make natural
recolonization of any extirpated population unlikely.
Climate Change
Our analyses under the Act include consideration of ongoing and
projected changes in climate. The terms ``climate'' and ``climate
change'' are defined by the Intergovernmental Panel on Climate Change
(IPCC). ``Climate'' refers to the mean (average) and variability of
different types of weather conditions over time, with 30 years being a
typical period for such measurements, although shorter or longer
periods also may be used (IPCC 2007, p. 78). The term ``climate
change'' thus refers to a change in the mean or variability of one or
more measures of climate (e.g., temperature or precipitation) that
persists for an extended period, typically decades or longer, whether
the change is due to natural variability, human activity, or both (IPCC
2007, p. 78). Various types of changes in climate can have direct or
indirect effects on species. These effects may be positive, neutral, or
negative and they may change over time, depending on the species and
other relevant considerations, such as the effects of interactions of
climate with other variables (e.g., habitat fragmentation) (IPCC 2007,
pp. 8-14, 18-19). In our analyses, we use our expert judgment to weigh
relevant information, including uncertainty, in our consideration of
various aspects of climate change.
There is a growing concern that climate change may lead to
increased frequency of severe storms and droughts (McLaughlin et al.
2002, p. 6074; Cook et al. 2004, p. 1015; Golladay et al. 2004, p.
504). Specific effects of climate change to mussels, their habitats,
and their fish hosts could include changes in stream temperature
regimes and changes in the timing and levels of precipitation, causing
more frequent and severe floods and droughts. Increases in temperature
and reductions in flow can also lower dissolved oxygen levels in
interstitial habitats, which can be lethal to juveniles (Sparks and
Strayer 1998, pp. 131-133). Even small increases in temperature can
cause reductions in the survival of freshwater mussel glochidia and
juveniles, and temperatures currently encountered in the temperate
United States during summers are close to or above the upper thermal
tolerances of early life stages of freshwater mussels (Pandolfo et al.
2010, pp. 965, 967). Effects to mussel populations from these
environmental changes could include reduced abundance and biomass,
altered species composition, and reduced host fish availability
(Galbraith et al. 2010, pp. 1180-1182). The present conservation
status, complex life histories, and specific habitat requirements of
mussels suggest that they may be quite sensitive to the effects of
climate change (Hastie et al. 2003, p. 45).
During high flows, flood scour can dislodge mussels potentially
causing them to be injured, buried, swept into unsuitable habitats, or
stranded and perish when flood waters recede (Vannote and Minshall
1982, p. 4105; Tucker 1996, p. 435; Hastie et al. 2001, pp. 107-115;
Peterson et al. 2011, unpaginated). Increased human demand and
competition for surface and ground water resources for irrigation and
consumption during drought can cause drastic reductions in stream flows
and alterations to hydrology (Golladay et al. 2004, p. 504; Golladay et
al. 2007, unpaginated). Extended droughts occurred in the Southeast
during 1998 to 2002, and again in 2006 to 2008. The effects of these
recent droughts on these mussels are unknown; however, substantial
declines in mussel diversity and abundance as a direct result of
drought have been documented in other southeastern streams (Golladay et
al. 2004, pp. 494-503; Haag and Warren 2008, p. 1165).
Nonindigenous Species
The Asian clam (Corbicula fluminea) has been introduced to the
Cumberland and Tennessee River drainages and may be adversely affecting
the fluted kidneyshell and slabside pearlymussel, particularly
juveniles, through direct competition for space and resources (Neves
and Widlak 1987, p. 6). Dense populations of Asian clams may ingest
large numbers of unionid sperm, glochidia, and newly metamorphosed
juveniles, and may actively disturb sediments, reducing habitable space
for juvenile native mussels or displacing them downstream (Strayer
1999, p. 82; Yeager et al. 2000, pp. 255-256).
Asian clam densities vary widely in the absence of native mussels
or in patches with sparse mussel concentrations, but Asian clam density
is rarely observed to be high in dense mussel beds, indicating that the
clam is unable to successfully invade small-scale habitat patches with
high unionid biomass (Vaughn and Spooner 2006, pp. 334-335). The
invading clam, therefore, appears to preferentially invade sites where
mussels are already in decline (Strayer 1999, pp. 82-83; Vaughn and
Spooner 2006, pp. 332-336) and does not appear to be a causative factor
in the decline of mussels in dense beds. However, an Asian clam
population that thrives in previously stressed, sparse mussel
populations might exacerbate unionid imperilment through competition
and impeding mussel population expansion (Vaughn and Spooner 2006, pp.
335-336).
Summary of Factor E
Other natural and manmade factors, such as alteration of natural
temperature regimes below dams; chemical contaminants; sedimentation;
small, isolated populations; and low genetic diversity, combined with
localized extinctions from point source pollution or accidental toxic
chemical spills, habitat modification and progressive degradation by
nonpoint source pollutants, natural catastrophic changes to habitat
through flood scour or drought as exacerbated by climate change, and
nonindigenous species are threats to remaining populations of the
fluted kidneyshell and slabside pearlymussel across their respective
ranges now and into the future.
Determination
We have carefully assessed the best scientific and commercial data
available regarding the past, present, and future threats to the fluted
kidneyshell and slabside pearlymussel. The Act defines an endangered
species as ``any species which is in danger of extinction throughout
all or a significant portion of its range,'' and a threatened species
as ``any species which is likely to become an endangered species within
the foreseeable future throughout all or a
[[Page 59285]]
significant portion of its range.'' As described in detail above, these
two species occupy only portions of their historical ranges, are
limited to fewer than 20 viable populations, and are currently at risk
throughout all of their respective ranges due to ongoing threats of
habitat destruction and modification (Factor A) and other natural or
manmade factors affecting their continued existence (Factor E).
Specifically, primary sources of stress and threats include
impoundments, mining, oil and gas exploration, sedimentation, chemical
contaminants, temperature regime alterations, recurring drought and
flooding, population fragmentation and isolation, loss of fish hosts,
and the introduced Asian clam. The data show that existing regulatory
mechanisms, such as the CWA, are inadequate to reduce these threats
(Factor D). These threats are currently impacting these species
throughout their ranges and are projected to continue and potentially
worsen in the future.
Species with small ranges, few populations, and small or declining
population sizes are the most vulnerable to extinction (Primack 2008,
p. 137). The effects of certain factors, particularly habitat
degradation and loss, catastrophic events, and introduced species,
increase in magnitude when population size is small (Soul[eacute] 1987,
pp. 33, 71; Primack 2008, pp. 133-135, 152). When combining the effects
of historical, current, and future habitat loss and degradation;
historical and future drought; and the exacerbating effects of small
and declining population sizes and curtailed ranges, the fluted
kidneyshell and slabside pearlymussel are in danger of extinction
throughout all of their ranges. In addition, any factor (i.e., habitat
loss or other natural and manmade factors) that results in a further
decline in habitat or individuals may be problematic for the long-term
recovery of these species. Therefore, based on the best available
scientific and commercial data, we list the fluted kidneyshell and
slabside pearlymussel as endangered species in accordance with sections
3(6) and 4(a)(1) of the Act.
Resource managers have been making attempts to reintroduce the
fluted kidneyshell into historical habitat over the past decade. These
mussels have been translocated from the Clinch River into the upper
Duck River, Nolichucky River, Big South Fork of the Cumberland River,
Little Tennessee River bypass below Calderwood Dam, Indian Creek and
North Fork Holston River. Despite all of these reintroduction attempts
only three sites are showing signs of any success. The only population
of the fluted kidneyshell known to be large, stable, and viable is in
the Clinch River, but it is in a relatively short reach of river
primarily in the vicinity of the Tennessee-Virginia State line. Based
on recent information, the overall population status of the fluted
kidneyshell is declining rangewide. We find that a threatened species
status is not appropriate for the fluted kidneyshell because of its
contracted range, because the threats are occurring rangewide and are
not localized, because the threats are ongoing and expected to continue
into the future, and because the reintroduction attempts have been
unable to stop or reduce the overall population decline.
There have been no reintroductions for the slabside pearly mussel.
The slabside pearlymussel has been extirpated from more than 50 percent
of the streams from which the species was historically known to occur
and occurs in only 13 extant populations. The overall population of the
slabside pearlymussel appears to be declining rangewide, with
relatively good numbers and apparent viability in just two streams
(Duck and Paint Rock Rivers). Most of the other populations are of
questionable viability and may be on the verge of extirpation (e.g.,
Powell and Hiwassee Rivers; Big Moccasin Creek). Therefore, we find
that a threatened species status is not appropriate for the slabside
pearlymussel because of its contracted range, because the threats are
occurring rangewide and are not localized, because the threats are
ongoing and expected to continue into the future, and because the
species is declining rangewide and many populations are on the verge of
extirpation.
Under the Act and our implementing regulations, a species may
warrant listing if it is endangered or threatened throughout all or a
significant portion of its range. The threats to the survival of these
species occur throughout the species' ranges and are not restricted to
any particular significant portion of their ranges. Accordingly, our
assessment and determination applies to these species throughout their
entire ranges.
Available Conservation Measures
Conservation measures provided to species listed as endangered or
threatened under the Act include recognition, recovery actions,
requirements for Federal protection, and prohibitions against certain
practices. Recognition through listing results in public awareness and
conservation by Federal, State, and local agencies; private
organizations; and individuals. The Act encourages cooperation with the
States and requires that recovery actions be carried out for all listed
species. The protection measures required of Federal agencies and the
prohibitions against certain activities involving listed wildlife are
discussed, in part, below.
The primary purpose of the Act is the conservation of endangered
and threatened species and the ecosystems upon which they depend. The
ultimate goal of such conservation efforts is the recovery of these
listed species, so that they no longer need the protective measures of
the Act. Subsection 4(f) of the Act requires the Service to develop and
implement recovery plans for the conservation of endangered and
threatened species. The recovery planning process involves the
identification of actions that are necessary to halt or reverse the
species' decline by addressing the threats to its survival and
recovery. The goal of this process is to restore listed species to a
point where they are secure, self-sustaining, and functioning
components of their ecosystems.
Recovery planning includes the development of a recovery outline
shortly after a species is listed, preparation of a draft and final
recovery plan, and revisions to the plan as significant new information
becomes available. The recovery outline guides the immediate
implementation of urgent recovery actions and describes the process to
be used to develop a recovery plan. The recovery plan identifies site-
specific management actions that will achieve recovery of the species,
measurable criteria that determine when a species may be downlisted or
delisted, and methods for monitoring recovery progress. Recovery plans
also establish a framework for agencies to coordinate their recovery
efforts and provide estimates of the cost of implementing recovery
tasks. Recovery teams (comprised of species experts, Federal and State
agencies, nongovernment organizations, and stakeholders) are often
established to develop recovery plans. When completed, the draft and
final recovery plans will be available on our Web site (http://www.fws.gov/endangered) and from our Tennessee Ecological Services
Field Office (see FOR FURTHER INFORMATION CONTACT).
Implementation of recovery actions generally requires the
participation of a broad range of partners, including other Federal
agencies, States, Tribes, nongovernmental organizations, businesses,
and private landowners. Examples of recovery actions include
[[Page 59286]]
habitat restoration (e.g., restoration of native vegetation), research,
captive propagation and reintroduction, and outreach and education. The
recovery of many listed species cannot be accomplished solely on
Federal lands because their range may occur primarily or solely on non-
Federal lands. To achieve recovery of these species requires
cooperative conservation efforts on private, State, and Tribal lands.
When this rule is effective (see DATES), funding for recovery
actions will be available from a variety of sources, including Federal
budgets, State programs, and cost share grants for non-Federal
landowners, the academic community, and nongovernmental organizations.
In addition, under section 6 of the Act, the States of Alabama,
Kentucky, Mississippi, Tennessee and Virginia will be eligible for
Federal funds to implement management actions that promote the
protection and recovery of these two species. Information on our grant
programs that are available to aid species recovery can be found at:
http://www.fws.gov/grants.
Please let us know if you are interested in participating in
recovery efforts for the fluted kidneyshell and slabside pearlymussel.
Additionally, we invite you to submit any new information on these
species whenever it becomes available and any information you may have
for recovery planning purposes (see FOR FURTHER INFORMATION CONTACT).
Section 7(a) of the Act requires Federal agencies to evaluate their
actions with respect to any species that is proposed or listed as
endangered or threatened and with respect to its critical habitat, if
any is designated. Regulations implementing this interagency
cooperation provision of the Act are codified at 50 CFR part 402.
Section 7(a)(4) of the Act requires Federal agencies to confer with the
Service on any action that is likely to jeopardize the continued
existence of a species proposed for listing or result in destruction or
adverse modification of proposed critical habitat. If a species is
listed subsequently, section 7(a)(2) of the Act requires Federal
agencies to ensure that activities they authorize, fund, or carry out
are not likely to jeopardize the continued existence of the species or
destroy or adversely modify its critical habitat. If a Federal action
may affect a listed species or its critical habitat, the responsible
Federal agency must enter into formal consultation with the Service.
Federal agency actions within the species habitat that may require
conference or consultation or both as described in the preceding
paragraph include management of and any other landscape altering
activities on Federal lands administered by the U.S. Forest Service;
issuance of section 404 CWA permits by the U.S. Army Corps of
Engineers; licensing of hydroelectric dams, and construction and
management of gas pipeline and power line rights-of-way approved by the
Federal Energy Regulatory Commission; issuance of 26a permits by the
Tennessee Valley Authority; construction and maintenance of roads or
highways funded by the Federal Highway Administration; and land
management practices administered by the U.S. Department of
Agriculture. It has been the experience of the Service from
consultations on other species, however, that nearly all section 7
consultations have been resolved so that the species have been
protected and the project objectives have been met.
The Act and its implementing regulations set forth a series of
general prohibitions and exceptions that apply to all endangered and
threatened wildlife. The prohibitions of section 9(a)(2), codified at
50 CFR 17.21 for endangered wildlife, make it illegal for any person
subject to the jurisdiction of the United States to take (includes
harass, harm, pursue, hunt, shoot, wound, kill, trap, capture, or
collect; or to attempt any of these), import, export, ship in
interstate commerce in the course of commercial activity, or sell or
offer for sale in interstate or foreign commerce any listed species.
Under the Lacey Act (18 U.S.C. 42-43; 16 U.S.C. 3371-3378), it is also
illegal to possess, sell, deliver, carry, transport, or ship any such
wildlife that has been taken illegally. Certain exceptions apply to
agents of the Service and State conservation agencies.
We may issue permits to carry out otherwise prohibited activities
involving endangered and threatened wildlife species under certain
circumstances. Regulations governing permits are codified at 50 CFR
17.22 for endangered species, and at 17.32 for threatened species. With
regard to endangered wildlife, a permit must be issued for the
following purposes: for scientific purposes, to enhance the propagation
or survival of the species, and for incidental take in connection with
otherwise lawful activities.
It is our policy, as published in the Federal Register on July 1,
1994 (59 FR 34272), to identify, to the maximum extent practicable at
the time a species is listed, those activities that would or would not
constitute a violation of section 9 of the Act. The intent of this
policy is to increase public awareness of the effect of a listing on
proposed and ongoing activities within the range of listed species. The
following activities could potentially result in a violation of section
9 of the Act; this list is not comprehensive:
(1) Unauthorized collecting, handling, possessing, selling,
delivering, carrying, or transporting of the species, including import
or export across State lines and international boundaries, except for
properly documented antique specimens of these taxa at least 100 years
old, as defined by section 10(h)(1) of the Act.
(2) Introduction of nonnative species, such as the Asian clam, that
compete with or prey upon these mussel species.
(3) Unauthorized modification of the channel, substrate,
temperature, or water flow of any stream or water body in which these
species are known to occur.
(4) Unauthorized discharge of chemicals or fill material into any
waters in which the fluted kidneyshell and slabside pearlymussel are
known to occur.
Questions regarding whether specific activities would constitute a
violation of section 9 of the Act should be directed to the Tennessee
Ecological Services Field Office (see FOR FURTHER INFORMATION CONTACT).
Requests for copies of the regulations concerning listed animals and
general inquiries regarding prohibitions and permits may be addressed
to the U.S. Fish and Wildlife Service, Endangered Species Permits, 1875
Century Boulevard, Suite 200, Atlanta, GA 30345; telephone: 404-679-
7140; facsimile: 404-679-7081.
Required Determinations
National Environmental Policy Act
We have determined that environmental assessments and environmental
impact statements, as defined under the authority of the National
Environmental Policy Act (NEPA; 42 U.S.C. 4321 et seq.), need not be
prepared in connection with listing a species as endangered or
threatened under the Endangered Species Act. We published a notice
outlining our reasons for this determination in the Federal Register on
October 25, 1983 (48 FR 49244).
References Cited
A complete list of all references cited in this final rule is
available on the Internet at http://www.regulations.gov, or upon
request from the Tennessee Ecological Services Field Office (see FOR
FURTHER INFORMATION CONTACT).
[[Page 59287]]
Authors
The primary authors of this final rule are the staff members of the
Tennessee Ecological Services Field Office.
List of Subjects in 50 CFR Part 17
Endangered and threatened species, Exports, Imports, Reporting and
recordkeeping requirements, Transportation.
Regulation Promulgation
Accordingly, we amend part 17, subchapter B of chapter I, title 50
of the Code of Federal Regulations, as follows:
PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS
0
1. The authority citation for part 17 continues to read as follows:
Authority: 16 U.S.C. 1361-1407; 1531-1544; 4201-4245, unless
otherwise noted.
0
2. Amend Sec. 17.11(h) by adding entries for ``Kidneyshell, fluted''
and ``Pearlymussel, slabside'' to the List of Endangered and Threatened
Wildlife in alphabetical order under ``CLAMS'':
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
* * * * * * *
Kidneyshell, fluted.............. Ptychobranchus U.S.A. (AL, KY, TN, Entire............. E 825 17.95(f) NA
subtentum. VA).
* * * * * * *
Pearlymussel, slabside........... Pleuronaia U.S.A. (AL, KY, MS, Entire............. E 825 17.95(f) NA
dolabelloides. TN, VA).
* * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
* * * * *
Dated: September 17, 2013.
Rowan W. Gould,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2013-23356 Filed 9-25-13; 8:45 am]
BILLING CODE 4310-55-P