Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition to Remove the Bliss Rapids Snail (Taylorconcha serpenticola) From the List of Endangered and Threatened Wildlife, 47536-47545 [E9-21949]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 178 (Wednesday, September 16, 2009)]
[Proposed Rules]
[Pages 47536-47545]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-21949]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R1-ES-2008-0073; 14420-1113-0000-C6]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition to Remove the Bliss Rapids Snail (Taylorconcha 
serpenticola) From the List of Endangered and Threatened Wildlife

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce a 
12-month finding on a petition to remove the Bliss Rapids snail 
(Taylorconcha serpenticola) from the Federal List of Endangered and 
Threatened Wildlife (List) pursuant to the Endangered Species Act of 
1973, as amended (Act) (16 U.S.C. 1531 et seq.). Based on a thorough 
review of the best scientific and commercial data available, the 
species continues to be restricted to a small geographic area in the 
middle-Snake River, Idaho, where it is dependent upon cool-water spring 
outflows. Although some threats identified at the time of listing in 
1992 no longer exist or have been moderated, ground water depletion and 
impaired water quality still threaten the Bliss Rapids snail. In 
addition, there are significant uncertainties about the effects of 
hydropower operations and New Zealand mudsnails on the

[[Page 47537]]

persistence of Bliss Rapids snails in riverine habitats. In the absence 
of the Act's protections, existing regulations are not likely to be 
sufficient to conserve the species. Given our current understanding of 
the species' geographic distribution, habitat requirements, and 
threats, the species continues to meet the definition of a threatened 
species under the Act. Therefore, we have determined that removing the 
Bliss Rapids snail from the List is not warranted at this time.

DATES: We made the finding announced in this document September 16, 
2009.

ADDRESSES: This notice is available on the Internet at https://www.fws.gov/idaho and at https://www.regulations.gov at Docket No. FWS-
R1-ES-2008-0073. Supporting documentation we used in preparing this 
notice will be available for public inspection, by appointment, during 
normal business hours at the U.S. Fish and Wildlife Service, Idaho Fish 
and Wildlife Office, 1387 S. Vinnell Way, Room 368, Boise, ID 87309; 
telephone (208) 378-5243; facsimile (208) 378-5262. New information, 
materials, comments, or questions concerning this species may be 
submitted to the Service at the above address.

FOR FURTHER INFORMATION CONTACT: Jeff Foss, Field Supervisor, U.S. Fish 
and Wildlife Service, Idaho Fish and Wildlife Office, (see ADDRESSES 
section). If you use a telecommunications device for the deaf (TDD), 
you may call the Federal Information Relay Service (FIRS) at 800-877-
8339.

SUPPLEMENTARY INFORMATION: 

Species Information

    The Bliss Rapids snail was first collected in 1959 at the Thousand 
Springs Preserve in Idaho's Snake River by Dwight Taylor (57 FR 59244; 
December 14, 1992) and formally described by Hershler et al. (Hershler 
et al. 1994, p. 235) as Taylorconcha serpenticola in 1994. The Bliss 
Rapids snail grows to approximately 0.08 to 0.16 inches (2.0 to 4.0 
millimeter (mm)) in height. The shell is clear to white but appears to 
have two morphs due to coloration of the periostracum (the shell's 
outer layer). The periostracum can be very light tan to dark brown-red 
resulting in the ``pale'' and ``orange'' forms, respectively. The Bliss 
Rapids snail has approximately 3.5 to 4.5 whorls (turn or curl in the 
shell) with the protoconch (apex or top of the shell) comprising about 
1.5 whorls. The apex (the highest point of the shell) is blunt.
    Bliss rapids snails hatch, reproduce, and die in a single year 
(Hershler et al. 1994, pp. 239, 240). They are dioecous, having 
strictly male and female individuals and may exhibit an iteroparous 
(more than one reproductive event in an individual's lifetime) 
reproductive strategy (Richards 2004, p. 119). The timing of 
reproduction apparently varies by habitat-type. Egg-laying normally 
occurs in spring colonies between December and March, while in river 
colonies egg laying occurs in January and February (Hershler et al. 
1994, p. 239). Eggs are laid singly, in small capsules attached to the 
bottoms or sides of rocks (Hershler et al. 1994, p. 239). Emergence of 
young typically takes place a few weeks after egg deposition depending 
on water temperature (Dillon 2000, p. 103), but specific timing and 
temperature information is lacking.
    Bliss Rapids snails primarily consume epilithic periphyton (diatom 
films that primarily grow on rock surfaces), as do many freshwater 
snails (Richards 2006b). They may also consume quantities of detritus, 
bacteria, and protozoa embedded in the simple sugar matrix (i.e., the 
periphyton) on the surfaces of benthic (bottom) substrates.

Range

    At the time of listing in 1992, the distribution of the Bliss 
Rapids snail was thought to be discontinuous over 204 miles of the 
Snake River in Idaho, between King Hill (river mile (RM) 546) and Lower 
Salmon Falls Dam (RM 573) with a disjunct occurrence at RM 749. The 
species' distribution upstream of Upper Salmon Falls Reservoir was 
known to be localized to spring complexes (i.e., Thousand Springs (RM 
585), Minnie Miller Springs (RM 585), Banbury Springs (RM 589), Niagara 
Springs (RM 599), and Box Canyon Springs (RM 588)) (57 FR 59244; 
December 14, 1992). This range was based on approximately 14 spring/
tributary collection points (Richards et al. 2006, p. 33). The reported 
occurrence at RM 749 is now regarded as erroneous because: (1) Samples 
from this collection have not been located to verify the occurrence 
(Frest 2002); (2) the reported collection site is 150 river miles 
upstream of the known distribution of the species (Pentec 1991 in 57 FR 
59244); and, (3) numerous collection efforts in and above American 
Falls Reservoir (U.S. Bureau of Reclamation (USBR) 2003; USBR 2004; 
USBR 2005; Gregg 2006), and in the upper Snake River (Fields 2006) have 
all failed to document the occurrence of the species.
    The current known range of the Bliss Rapids snail is similar to 
what was described at the time of listing (minus the erroneous location 
at American Falls Reservoir). Increased sampling effort has documented 
its presence at many more locations within its range. Based on 837 
sample events conducted by the Idaho Power Company (IPC), the Bliss 
Rapids snail is documented to occur within the non-reservoir sections 
of the middle Snake River from approximately RM 547 to RM 572, and RM 
580 (Richards et al. 2006, pp. 33-38). This represents a refined 
distribution since the time of listing in 1992 due to more accurate 
survey data.
    Bliss Rapids snails are also known to occur in 14 springs or Snake 
River tributary streams (from RM 552.8 to RM 604.5) derived from cold 
water springs including: Bancroft Springs; Thousand Springs and Minnie 
Miller Springs (Thousand Springs Preserve); Banbury Springs; Niagara 
Springs; Crystal Springs; Briggs Springs; Blue Heart Springs; Box 
Canyon Creek; Riley Creek; Sand Springs Creek; Elison Springs; the 
Malad River; Cove Creek (a tributary to the Malad River); and the 
headwater springs to Billingsley Creek (Richards et al. 2006, p. 2; 
USFWS 2008a, p. 6).
    The U.S. Geological Survey (USGS) reported finding several Bliss 
Rapids snails at Blue Lakes (approximately Snake River mile 610.4) in 
1994, but surveys of this site in 1996 and 2007 did not locate the 
species (Mebane 2007, Grotheer 2008). Over 200 springs or spring 
clusters have been mapped or identified on the north side of the Snake 
River canyon (Clark and Ott 1996, p. 559) where the Bliss Rapids snail 
has been documented to occur. Springs also occur on the south side of 
the Snake River canyon (Clark and Ott 1996, p. 559), but studies 
conducted by the Idaho Power Company (IPC) have not observed Bliss 
Rapids colonies in springs or tributaries on the south side (Bates and 
Richards 2008). The species is likely present at additional springs on 
private lands that have not been sampled (e.g., Hopper 2006b).
    In summary, we now know the Bliss Rapids snail to be distributed 
discontinuously over 22 miles, from RM 547-560, RM 566-572, and at RM 
580 on the Snake River and to occur in 14 springs or tributaries to the 
Snake River. The area between RM 561-565 represents reservoir areas 
where the Bliss Rapids snail does not occur. The species' overall 
geographic range has not substantially changed since it was first 
described by Hershler et al. (1994), but the species has been detected 
at more locations within its range.

Habitat Use

    The Bliss Rapids snail occurs in cold water springs and spring-fed 
tributaries to the Snake River (hereafter referred to

[[Page 47538]]

as spring colonies), and in some reaches of the Snake River (hereafter 
referred to as river colonies). Available data indicate that spring 
colonies are consistently larger, at least in terms of density and 
relative abundance, than river colonies (Stephenson and Bean 2003, pp. 
12, 18; Stephenson et al. 2004, p. 24; Richards et al. 2006, pp. 97-
99). The species is absent from reservoirs (Hershler et al. 1994, p. 
237; Finni 2003, p. 28; Richards et al. 2006, p. 35), patchily 
distributed and in low densities in the mainstem Snake River 
(Stephenson et al. 2004, pp. 11, 22, 24; Richards et al. 2006, p. 37), 
and relatively abundant, though patchily distributed in spring habitats 
(Stephenson and Bean 2003, pp. 12, 18; Richards 2004, pp. 59-69; 
Richards et al. 2006, p. 37).
    The Bliss Rapids snail is known to occur on stable, cobble 
substrates in unimpounded sections of the mainstem Snake River 
(Richards et al. 2006, pp. 35, 41), on cobble-boulder substrates in the 
Malad River (Stephenson and Clark 2004, p. 33), and on various 
substrates in several spring complexes (Stephenson and Myers 2003, p. 
5). The species is generally not found in, or on, very fine (silt) 
sediments (Hershler et al. 1994, p. 237; Richards et al. 2006, p. 23), 
but has been documented infrequently on sand and gravel (Stephenson and 
Myers 2003, p. 5), aquatic vegetation (Lysne 2006), and coarse woody 
debris (Hopper 2006a, Lysne 2006). A notable exception to this 
characterization of habitat use is the presence of Bliss Rapids snails 
on fine sediments (silt/gravel) at the upper pool in Cove Creek 
(Stephenson and Myers 2003, p. 5), a cold water spring creek tributary 
to the Malad River. Overall, the cobble-boulder substrate is considered 
to be the dominant habitat type where the Bliss Rapids snail is found 
(Richards et al. 2006, p. 51).
    Field studies and observations have demonstrated that the species 
uses the sides and bottoms of cobbles preferentially to the exclusion 
of cobble tops (Richards 2004, pp. 32-34). The Bliss Rapids snail is 
found at various water depths in springs ranging from 0.3 to 3 feet 
(0.1-1 meters (m)), and in spring-fed tributary habitats ranging from 
0.07 to 3.35 feet (0.02-1.02 m) (Stephenson and Myers 2003, pp. 23-35; 
Stephenson and Clark 2004, p. 32). This species has also been 
documented to occur at depths up to 20 feet (6.1 m) in the mainstem 
Snake River (Richards et al. 2006, p. 52). Most Bliss Rapids snails are 
found in less than 3 feet (0.9 m) of water (Richards et al. 2006, p. 
43) but this could be due to sampling effort.
    The Bliss Rapids snail has been collected in water temperatures 
ranging from 44.6 to 69.8 degrees Fahrenheit (F) (7 to 21 degrees 
Celsius (C)) (Finni 2003, p. 14; Clark et al. 2005, p. 55), but is 
generally found in water temperatures between 59 and 60.8 degrees F (15 
and 16 degrees C) (Hershler et al. 1994, p. 237). Richards et al. 
(2001, p. 377) collected Bliss Rapids snails from Banbury Springs in 
thermally constant waters measuring 55.2 to 61.5 degrees F (12.9 to 
16.4 degrees C), and Stephenson and Clark (2004, p. 32) collected the 
species from the Malad River in water measuring 57.2 to 59.0 degrees F 
(14 to 15 degrees C).
    Richards et al. (2006, pp. 39-51) analyzed the physio-chemical data 
from all IPC collections in river, spring, and spring-influenced sites 
and determined the probability of encountering Bliss Rapids snails for 
various parameters. The best predictors of Bliss Rapids snail presence 
(i.e., having statistically significant regression values based on 
large samples), in order of significance, were dominant substrate, 
conductivity (a measure of total dissolved solids), depth, dissolved 
oxygen, and temperature (Richards et al. 2006, p. 41).
    In summary, based on available information, the Bliss Rapids snail 
occurs in riverine and spring or spring-influenced habitats but is not 
known to occur in reservoir habitats. It is known from the Snake River 
(22 miles), the Malad River (1 mile), Cove Creek (0.4 mile), and in 14 
springs. In the Snake River the species is predominately associated 
with cobble-boulder substrates; substrate use in spring complexes is 
more variable. The species is generally not found in, or on, very fine 
sediments. It has been collected at various water depths in springs 
ranging from 0.3 to 3 feet (0.1-0.9 m), and in spring-fed tributary 
habitats ranging 0.07 to 3.35 feet (0.02-1.02 m). This species has also 
been documented to occur at depths up to 20 feet (6.1 m) in the 
mainstem Snake River. Most Bliss Rapids snails are found in less than 3 
feet (0.9 m) of water, but this may be an artifact of sampling effort 
rather than true habitat selection. The species has been observed in 
water temperatures ranging from 44.6 to 69.8 degrees F (7 to 21 degrees 
C), but is generally found in water temperatures between 59 and 60.8 
degrees F (15 and 16 degrees C).

Densities and Relative Abundance

    It is difficult to estimate the density and relative abundance of 
Bliss Rapids snail colonies. The species is documented to reach high 
densities in cold-water springs and tributaries in the Hagerman reach 
of the middle Snake River (Stephenson and Bean 2003, pp. 12, 18; 
Stephenson et al. 2004, p. 24), whereas colonies in the mainstem Snake 
River (Stephenson and Bean 2003, p. 27; Stephenson et al. 2004, p. 24) 
tend to have lower densities (Richards et al. 2006, p. 37). Bliss 
Rapids snail densities in Banbury Springs averaged approximately 32.53 
snails per square foot (350 snails per square meter) on three habitat 
types (vegetation, edge, and run habitat as defined by Richards et al. 
2001, p. 379). Densities greater than 790 snails per square foot (5,800 
snails per square meter) have been documented at the outlet of Banbury 
Springs (Morgan Lake outlet) (Richards et al. 2006, p. 99).
    In an effort to account for the high variability in snail densities 
and their patchy distribution, researchers have used predictive models 
to give more accurate estimates of population size in a given area 
(Richards 2004, p. 58). In the most robust study to date, predictive 
models estimated between 200,000 and 240,000 Bliss Rapids snails in a 
study area measuring 58.1 square feet (625 square meters) in Banbury 
Springs, the largest known colony (Richards 2004, p. 59). Due to data 
limitations, this model has not been used to extrapolate population 
estimates to other spring complexes, tributary streams, or mainstem 
Snake River colonies. However, with few exceptions (i.e., Thousand 
Springs and Box Canyon), Bliss Rapids snail colonies are much smaller 
in areal extent than the colony at Banbury Springs, occupying only a 
few square feet.

Previous Federal Actions

    The Service listed the Bliss Rapids snail as threatened on December 
14, 1992 (57 FR 59244). At that time it was an undescribed monotypic 
genus in the family Hydrobiidae. Subsequent research in 1994 formalized 
its taxonomic status and its scientific name--Taylorconcha serpenticola 
(Hershler et al. 1994).
    Based on the best available data at the time of listing, we 
determined that the Bliss Rapids snail was threatened by: proposed 
construction of new hydropower dams, the operation of existing 
hydropower dams, degraded water quality, water diversions, the 
introduced New Zealand mudsnail (Potamopyrgus antipodarum), and the 
lack of existing regulatory protections (57 FR 59244). In 1995, we 
published the Snake River Aquatic Species Recovery Plan (Plan), which 
included the Bliss Rapids snail (USFWS 1995). Critical habitat has not 
been designated for this species.

[[Page 47539]]

    On July 27, 2004, we initiated a 5-year status review for the 
species in accordance with section 4(c)(2) of the Act (69 FR 44676). On 
December 26, 2006, the Service received a petition from the Governor of 
Idaho and IPC requesting that the Bliss Rapids snail be removed from 
the List. On June 6, 2007, the Service published a Federal Register 
notice announcing that the petition presented substantial scientific 
information indicating that removing the Bliss Rapids snail from the 
List may be warranted, and the initiation of a 12-month status review 
of the species to be conducted concurrent with our 5-year status review 
(72 FR 31250). A 30-day peer review was completed in January 2008, on 
the draft status review document of the best available information and 
scientific literature (USFWS 2008a).
    As part of the 12-month status review, we used a structured 
decision analysis process (USFWS 2008b) to assist us in making our 12-
month finding. A component of the structured decision analysis was the 
formation of an expert scientific review panel that provided us with 
information regarding the current status of the species and primary 
threats. The Service reopened the public comment period on its 90-day 
finding from August 12 to August 27, 2008 (73 FR 46867), to allow the 
public to access and provide comments on the scientific review panel's 
results and other documents. No additional comments were received.

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533 et seq.) and implementing 
regulations (50 CFR part 424) set forth procedures for adding species 
to, removing species from, or reclassifying species on the Federal List 
of Endangered and Threatened Wildlife. Section 4(b)(3)(A) of the Act 
requires that for any petition containing substantial scientific and 
commercial information that listing, delisting, or reclassification may 
be warranted, we make a finding within 12 months of receiving the 
petition, on whether the petitioned action is: (a) Not warranted; (b) 
warranted; or (c) warranted, but that immediate proposal of a 
regulation implementing the petitioned action is precluded by other 
pending proposals to determine whether other species are threatened or 
endangered.
    Under section 4 of the Act, a species may be determined to be 
endangered or threatened on the basis of any of the following five 
factors: (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range; (B) overutilization for 
commercial, recreation, 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 must consider these same five factors in 
delisting a species. We may delist a species according to 50 CFR 
424.11(d) if the best available scientific and commercial data indicate 
that the species is neither endangered nor threatened for the following 
reasons: (1) The species is extinct; (2) the species has recovered and 
is no longer endangered or threatened; or (3) the original scientific 
data used at the time the species was classified were in error.
    A species is ``endangered'' for purposes of the Act if it is in 
danger of extinction throughout all or ``a significant portion of its 
range'' and is ``threatened'' if it is likely to become endangered 
within the foreseeable future throughout all or a significant portion 
of its range. The word ``range'' in the significant portion of its 
range (SPR) phrase refers to the range in which the species currently 
exists. The word ``significant'' in the SPR phrase refers to the value 
of that portion to the conservation of the species. For the purposes of 
this analysis, we will evaluate whether the currently listed species, 
the Bliss Rapids snail, should be considered threatened or endangered. 
Then we will consider whether there are any portions of the species' 
range in which it is in danger of extinction or likely to become 
endangered within the foreseeable future.

Factor A. The Present or Threatened Destruction, Modification, or 
Curtailment of the Species' Habitat or Range

Construction of New Hydropower Dams
    In our 1992 final rule listing the Bliss Rapids snail as a 
threatened species, we stated: ``Six proposed hydroelectric projects, 
including two high dam facilities, would alter free flowing river 
reaches within the existing range of [the Bliss Rapids snail]. Dam 
construction threatens the [Bliss Rapids snail] through direct habitat 
modification and moderates the Snake River's ability to assimilate 
point and non-point pollution. Further hydroelectric development along 
the Snake River would inundate existing mollusk habitats through 
impoundment, reduce critical shallow, littoral shoreline habitats in 
tailwater areas due to operating water fluctuations, elevate water 
temperatures, reduce dissolved oxygen levels in impounded sediments, 
and further fragment remaining mainstem populations or colonies of [the 
Bliss Rapids snail]'' (57 FR 59251).
    Proposed hydroelectric projects discussed in the 1992 final listing 
rule are no longer moving forward. The A.J. Wiley project and Dike 
Hydro Partners preliminary permits have lapsed; the Kanaka Rapids, 
Empire Rapids, and Boulder Rapids permits were denied by the Federal 
Energy Regulatory Commission (FERC) in 1995; there was a notice of 
surrender of the preliminary permit for the River Side Project in 2002; 
and two other proposed projects, the Eagle Rock and Star Falls 
Hydroelectric Projects, were denied preliminary permits by the FERC. In 
2003, a notice was provided of surrender of the preliminary permit for 
the Auger Falls Project. Information provided by the State of Idaho 
indicates that all proposals and preliminary permits for the 
construction of new dams along the mid-Snake River have either lapsed 
or been denied by the FERC (Caswell 2006).
Operation of Existing Hydropower Dams
    In the December 14, 1992, final listing rule we stated: ``Peak-
loading, the practice of artificially raising and lowering river levels 
to meet short-term electrical needs by local run-of-the-river 
hydroelectric projects also threatens [the Bliss Rapids snail]. Peak-
loading is a frequent and sporadic practice that results in dewatering 
mollusk habitats in shallow, littoral shoreline areas * * * these 
diurnal water fluctuations [prevent the Bliss Rapids snail] from 
occupying the most favorable habitats'' (57 FR 59252). The Bliss Rapids 
snail occurs in riverine and spring or spring-influenced habitats but 
is not known to occur in reservoir habitats. Peak loading operations 
within the range of river colonies of the Bliss Rapids snail occur 
below the Bliss Dam (RM 560) and the Lower Salmon Falls Dam (RM 573) 
(USFWS 2004, pp. 19, 20). For example, at the Bliss Dam (Stephenson and 
Bean 2003, p. 30) the Snake River can experience daily fluctuation of 
water levels from hydropower generating activities (peak loading) up to 
7 feet (2.1 m). It appears that Bliss Rapids snails are found primarily 
in areas less than 3 feet (0.9 m) deep, although this may be an 
artifact of more intensive sampling at shallow depths (Richards et al. 
2006, pp. 43, 52-56). Nevertheless, our current understanding based on 
the best available information, is that a majority of Bliss Rapids 
snails in the Snake River occupy shallow water. Furthermore, Bliss 
Rapids snails in these shallow-water areas are susceptible to the 
effects from peak loading operations, including desiccation and 
freezing when water

[[Page 47540]]

levels drop and expose snails to atmospheric conditions.
    Laboratory studies have shown that peak-loading during winter 
months, a time when the species is reproducing, is likely to result in 
mortality of individual Bliss Rapids snails. Air temperatures within 
the range of Bliss Rapids snails in Idaho regularly fall below 32 
degrees F (0 degrees C) between November and March (Richards 2006a, p. 
28). In a laboratory study conducted by Richards (2006a, p. 12), half 
of the Bliss Rapids snails subjected to a temperature of 19 degrees F 
(minus 7 degrees C) died in less than an hour. In a field study, 
Richards (unpublished data, cited in Richards et al. 2006, pp. 125-126) 
found that Bliss Rapids snails could survive for many hours to several 
days in moist conditions (i.e., undersides of cobbles) and when air 
temperatures were above freezing (32 degrees F (0 degrees C)) (Richards 
et al. 2006, p. 125). Although the mortality rate outside of these 
conditions has not been documented in field studies or after an actual 
peak loading event, work by other researchers, utilizing laboratory-
controlled aquaria, found Bliss Rapids snail mortality to be up to 100 
percent under conditions characteristic (winter low and summer high 
temperatures) of some hydropower operations in the middle Snake River 
(Richards and Kerans 2007, p. 4). Based on the above information, peak 
loading likely affects individual Bliss Rapids snails through 
desiccation and freezing but the effects of peak loading on the 
survival of Bliss Rapids snail colonies in riverine habitats is unknown 
at this time.
Degraded Water Quality
    In the 1992 final listing rule we stated: ``The quality of water in 
[snail] habitats has a direct effect on the species survival. The 
[Bliss Rapids snail] require[s] cold, well-oxygenated unpolluted water 
for survival. Any factor that leads to deterioration in water quality 
would likely extirpate [the Bliss Rapids snail]'' (57 FR 59252). New 
information has become available indicating some improvements to Snake 
River water quality. Significant nutrient and sediment reduction has 
occurred in the Snake River following implementation of the Idaho 
Nutrient Management Act and regulated Total Maximum Daily Load (TMDL) 
reductions from the mid-1990s to the present (Richards et al. 2006, pp. 
5-6, 86). The Mid-Snake River reach also receives a large infusion of 
clean, cold-water spring flows and supports the highest densities and 
occurrence of Bliss Rapids snails.
    Hypereutrophy (planktonic algal blooms and nuisance rooted aquatic 
plant growths), prior to listing in 1992, was very severe during 
drought cycles when deposition of sediments and organic matter 
blanketed river substrate often resulting in unsuitable habitat 
conditions for Bliss Rapids snails. Although some nutrient and sediment 
reduction has been documented in the Snake River since listing 
(Richards et al. 2006, p. 5), there are still large inflows of 
agriculture and aquaculture runoff entering the river at Twin Falls to 
Lower Salmon Falls dam (RM 573). As a result, nutrient and sediment 
concentrations can be relatively high in this portion of the river, 
especially during lower summer flows (Richards et al. 2006, p. 91).
    Phosphorus concentrations, the key nutrient leading to 
hypereutrophic conditions in the middle Snake River, exceeded 
Environmental Protection Agency (USEPA) guidelines for the control of 
nuisance algae at numerous locations along the Snake River from 1989 to 
2002, including areas immediately upstream of Bliss Rapids snail 
colonies (Hardy et al. 2005, p. 13). Several water quality assessments 
have been completed by the USEPA, USBR, and IPC, and all generally 
agree that water quality in the Snake River of southern Idaho meets 
Idaho water quality standards for aquatic life for some months of the 
year, but may not meet these standards when temperatures are high and 
flows are low (Meitl 2002, p. 33). Idaho Department of Environmental 
Quality's (IDEQ) 2005 performance and progress report to the USEPA 
states that projects are meeting the Idaho non-point source pollution 
program goals (IDEQ 2006, 115 pp.). Others report that water quality 
has not improved appreciably between 1989 and 2002 (Hardy et al. 2005, 
pp. 19-21, 49, 51).
    Several reaches of the Snake River are classified as water-quality-
impaired due to the presence of one or more pollutants (e.g., Total 
Phosphorus (TP), sediments (TSS), total coliforms) in excess of State 
or Federal guidelines. Nutrient-enriched waters primarily enter the 
Snake River via springs, tributaries, fish farm effluents, municipal 
waste treatment facilities, and irrigation returns (USEPA 2002, pp. 4-
18 to 4-24). Irrigation water returned to rivers is generally warmer, 
contains pesticides or pesticide byproducts, has been enriched with 
nutrients from fish farms and land-based agriculture (e.g., nitrogen 
and phosphorous), and frequently contains elevated sediment loads. 
Pollutants in fish farm effluent include nutrients derived from 
metabolic wastes of the fish and unconsumed fish food, disinfectants, 
bacteria, and residual quantities of drugs used to control disease 
outbreaks. Furthermore, elevated levels of fine sediments, nitrogen, 
and trace elements (including cadmium, chromium, copper, lead, and 
zinc), have been measured immediately downstream of several aquaculture 
discharges (Hinson 2003, pp. 44-45). Additionally, concentrations of 
lead, cadmium, and arsenic have been previously detected in snails 
collected during a research study in the Snake River (Richards 2002). 
The effects of these elevated levels of nutrients and trace elements on 
Bliss Rapids snails, both individually and synergistically, are not 
fully understood. However, studies have shown another native Snake 
River snail, the Jackson Lake springsnail (Pyrgulopsis robusta), to be 
relatively sensitive to copper (a common component in algaecides) and 
pentachlorophenol, a restricted use pesticide/wood preservative 
(Ingersoll 2006), and Bliss Rapids snails are known to be highly 
sensitive to copper, ammonia, and pentachlorophenol (Besser et al. 
2008).
Water Diversions and Ground Water Withdrawals
    Threats to cold water spring-influenced habitats from ground water 
withdrawal and diversions for irrigation and aquaculture are not as 
they were perceived when the Bliss Rapids snail was listed in 1992. At 
the time the species was listed in 1992, the threat from ground water 
withdrawal was identified only at Box Canyon, and the scope of this 
threat was underestimated. Based on the best available data, we now 
know that this threat is likely to affect the Bliss Rapids snail 
throughout its range. In concert with the historical losses of habitat 
to surface diversions of spring water for irrigation and aquaculture, 
the continuing decline of the groundwater aquifer is one of the primary 
threats to the long-term viability of the Bliss Rapids snail.
    Average annual spring flows increased from about 4,400 cubic feet 
per second (cfs) in 1910, to approximately 6,500 cfs in the early 
1960s, because widespread flood irrigation caused artificial recharge 
of the aquifer (Richards et al. 2006, pp. 84, 87). As a result of more 
efficient irrigation practices from 1960 to the present (i.e., 
switching from flood irrigation or direct surface diversion to more 
efficient center-pivot irrigation systems utilizing ground water), more 
water was pumped from the aquifer while water percolation into the 
aquifer

[[Page 47541]]

declined, resulting in declines (from the high values of the 1960s) in 
average annual spring flows to about 5,000 cfs (Richards et al. 2006, 
pp. 84, 87). Although the current spring flow levels are total about 15 
percent higher than average spring flows measured in 1910, they are 
declining. We anticipate spring flows will likely continue to decline 
in the near future, even as water-conservation measures are implemented 
and are being developed as water demands in the vicinity continue to 
increase (USFWS 2008b).
    The State of Idaho has taken steps to improve ground water recharge 
and limit new ground water development within the eastern Snake River 
plain; however, the Snake River Plain aquifer level continues to 
decline (USFWS 2008b). Effects from the over-allocation of ground water 
and the subsequent declining ground water levels appear to be more of a 
threat than previously thought. Evidence indicates that springs from 
the Eastern Snake River Aquifer where the Bliss Rapids snail resides 
depend on ground water levels and that the ground water levels are 
declining (USFWS 2008b) even with ongoing measures attempting to 
address the decline (Caswell 2007). Spring sites are important since 
Bliss Rapids snail colonies that occur in springs have been shown to be 
a source of genetic diversity to riverine colonies and to contain four 
times as many private (i.e., unique) alleles (n=16) compared to 
riverine populations (Liu and Hershler 2009, p. 1296). Colonies in 
springs or at their outflows are also the most dense, may account for 
most of the reproductive output of the species, and likely act as 
refugia from competition with invasive New Zealand mudsnails (see 
Factor E, below). Finally, if spring colonies are lost, particularly 
those at the upstream end of the species' distribution, the probability 
of recolonization is likely to be extremely small (USFWS 2008b).
    Summary of Factor A: Our understanding of the threats to the Bliss 
Rapids snail has changed since we listed the species in 1992. Some 
threats are now known to be removed (i.e., new hydropower dam 
construction) while other threats have emerged (i.e., depletion of 
groundwater that supports the spring colonies). All proposals for the 
construction of new hydropower dams have either expired or been 
withdrawn. The Bliss Rapids snail occurs in riverine and spring or 
spring-influenced habitats, but is not known to occur in reservoir 
habitats. Some colonies of Bliss Rapids snails are known to occur in 
shallow-water areas that are susceptible to peak loading operations 
(i.e., below the Bliss Dam (RM 560) and the Lower Salmon Falls Dam (RM 
573)). Individual snails may be affected by desiccation and freezing 
when water levels drop and expose snails to atmospheric conditions, but 
the effects on these colonies are unknown. Water quality appears to 
have improved in the Snake River, but new research has indicated that 
the species is sensitive to the toxic effects of some aquatic 
contaminants such as copper, which is known to be used in aquaculture 
and discharged from facilities into the Snake River. Springs or spring-
influenced habitats are vulnerable from the effects of ongoing and 
anticipated future ground water depletion and degraded ground water 
quality. Spring flows at several occupied spring sites have been 
declining due to continued ground water withdrawal from the Eastern 
Snake River Plain Aquifer. If spring colonies are lost, it is unlikely 
that areas would be recolonized and a loss of occupied springs may 
reduce genetic diversity and eliminate rare alleles. Spring colonies 
are also important as they may provide refugia from competition with 
New Zealand mudsnails (see Factor E, below). Therefore, destruction, 
modification, or curtailment of the Bliss Rapids snail's habitat or 
range is an ongoing primary threat to the Bliss Rapids snail that is 
likely to contribute to the species becoming endangered in the 
foreseeable future.

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

    Based on the best available scientific and commercial information, 
we believe that overutilization for commercial, recreational, 
scientific or educational purposes is not currently placing the Bliss 
Rapids snail in danger of extinction, and is not likely to result in 
the endangerment or extinction of the species in the foreseeable 
future. There is no known commercial or recreational use of the species 
and collections for scientific or educational purposes are likely 
limited in scope and extent. While collection could result in mortality 
of individuals within a small area, it is unlikely to have a population 
level effect because only a few individuals and institutions are 
interested in collecting a small number of individuals of the species.

Factor C. Disease or Predation

    Parasitic trematodes similar to those of the genus Microphallus 
have been identified in some freshwater snails in Idaho (e.g., 
Pyrgulopsis robusta); however, the occurrence of trematode parasites in 
Bliss Rapids snail has not been studied (Dybdahl et al. 2005, p. 8).
    Predators of the Bliss Rapids snail have not been documented, but 
we assume that some predation by native and nonnative species occurs. 
Predation on aquatic snails by crayfish and fish is well documented 
(Lodge et al. 1994, p. 1265; Martin et al. 1992, p. 476; Merrick et al. 
1992, p. 225; Lodge et al. 1998, p. 53).
    Based on the best available scientific and commercial information, 
disease or predation is not currently threatening the viability of the 
Bliss Rapids snail and is not expected to threaten its viability in the 
foreseeable future.

Factor D. Inadequacy of Existing Regulatory Mechanisms

    In the 1992 final listing rule, we found inadequate regulatory 
mechanisms to be a threat because: (1) Regulations were inadequate to 
curb further water withdrawal from ground water spring outflows or 
tributary spring streams; (2) it was unlikely that pollution control 
regulations would reverse the trend in nutrient loading in the near 
future; (3) there was a lack of State-mandated protections for 
invertebrate species in Idaho; and (4) regulations did not require FERC 
or the U.S. Army Corps of Engineers to address Service concerns 
regarding licensing hydroelectric projects or permitting projects under 
the Clean Water Act (CWA) for unlisted snails. Below, we address each 
of these concerns in turn.
Ground Water Withdrawal Regulations
    The Idaho Department of Water Resources (IDWR) manages water in the 
State of Idaho. Among the IDWR's responsibilities is the development of 
the State Water Plan (IDWR 2006a). The State Water Plan was updated in 
1996 and included a table of Federally threatened and endangered 
species in Idaho, such as the Bliss Rapids snail. The State Water Plan 
outlines objectives for the conservation, development, management, and 
optimum use of all unappropriated waters in the State. One of these 
objectives is to ``maintain, and where possible enhance water quality 
and water-related habitats'' (IDWR 2006a). It is the intent of the 
State Water Plan that any water savings realized by conservation or 
improved efficiencies is appropriated to other beneficial uses (e.g., 
agriculture, hydropower, or fish and wildlife).
    Another IDWR regulatory mechanism is the ability of the Idaho Water 
Resource Board to designate ``in-stream flows'' (IDWR 2006b). The IDWR 
currently has 89 licensed water rights for minimum in-stream flows in 
Idaho

[[Page 47542]]

(IDWR 2006b). Of these, 11 potentially have conservation benefits for 
Bliss Rapids snails (i.e., provide for minimum in-stream flows near 
tributary spring outflows that provide habitat for Bliss Rapids 
snails). However, individuals that hold water rights with earlier 
priority dates have the right to fill their needs before the minimum 
stream flow is considered. If there is not enough water available to 
satisfy all of the water rights, then the senior water rights are 
satisfied first, and so on in order, until there is no water left. It 
is the junior water right holders that do not get water when there is 
not enough to satisfy all the water rights. Senior diversions can 
legally dewater the stream in a drought year or when low flows occur, 
leaving no water for the minimum stream flow (IDWR 2009), therefore 
impacting species such as the Bliss Rapids snail.
    The IDWR and other State agencies have also created additional 
regulatory mechanisms that limit future surface and ground water 
development; they include the continuation of various moratoria on new 
consumptive water rights and the designation of Water Management 
Districts (Caswell 2007). The State is attempting to stabilize aquifer 
levels and enhance cold water spring outflows from the Eastern Snake 
River Plain by implementing water conservation measures to be proposed 
in the Comprehensive Aquifer Management Plan (CAMP) for this area 
(Barker et al. 2007). The goal of the CAMP is to ``sustain the economic 
viability and social and environmental health of the Eastern Snake 
Plain by adaptively managing a balance between water use and 
supplies.'' The CAMP will include several alternatives in an attempt to 
increase water supply, reduce withdrawals from the aquifer, and 
decrease overall demand for groundwater (Barker et al. 2007).
    In addition, the State of Idaho established moratoria in 1993 (the 
year after listing of the Bliss Rapids snail) that restricted further 
surface-water and groundwater withdrawals for consumptive uses from the 
Snake River Plain aquifer between American Falls Reservoir and C.J. 
Strike Reservoir. The 1993 moratoria were extended by Executive Order 
in 2004 (Caswell 2006, attachment 1). However, these actions have not 
yet resulted in stabilization of aquifer levels. Depletion of spring 
flows and declining groundwater levels are a collective effect of 
drought conditions, changes in irrigation practices (the use of 
central-pivot sprinklers contribute little to groundwater recharge), 
and groundwater pumping (University of Idaho 2007). The effects of 
groundwater pumping downstream in the aquifer can affect the upper 
reaches of the aquifer, and the effects of groundwater pumping can 
continue for decades after pumping ceases (University of Idaho 2007).
    Thus, we anticipate groundwater levels will likely continue to 
decline in the near future, even as water-conservation measures are 
implemented, and are being developed. Furthermore, species associated 
with these springs that are dependent upon the presence of water, such 
as the Bliss Rapids snail, will likely experience local extinctions 
without the opportunity for recolonization (USFWS 2008b). Loss of a 
colony from any individual habitat patch, without subsequent 
recolonization, increases the extinction risk for the species as a 
whole, a phenomenon dubbed the ``extinction ratchet'' (Burkey and Reed 
2006, p. 11).
Pollution Control Regulations
    Since the 1992 final listing rule, reductions in TSS and TP loading 
have improved water quality in localized reaches of the Snake River 
(Buhidar 2005) (see Factor A above). Various State-managed water 
quality programs are being implemented within the range of the Bliss 
Rapids snail. These programs are tiered off the Clean Water Act (CWA), 
which requires States to establish water-quality standards that provide 
for (1) the protection and propagation of fish, shellfish, and 
wildlife, and (2) recreation in and on the water. As required by the 
CWA, Idaho has established water-quality standards (e.g., for water 
temperature and dissolved oxygen) for the protection of cold-water 
biota (e.g., invertebrate species) in many reaches of the Snake River. 
The CWA also specifies that States must include an antidegradation 
policy in their water quality regulations that protects water-body uses 
and high-quality waters. Idaho's antidegradation policy, updated in the 
State's 1993 triennial review, is detailed in their Water Quality 
Standards (IDEQ 2009).
    The IDEQ works closely with the USEPA to manage point and non-point 
sources of pollution to water bodies of the State through the National 
Pollutant Discharge Elimination System (NPDES) program under the CWA. 
IDEQ has not been granted authority by the USEPA to issue NPDES permits 
directly; all NPDES permits are issued by the USEPA Region 10 (USEPA 
2009). These NPDES permits are written to meet all applicable water-
quality standards established for a water body to protect human health 
and aquatic life. Waters that do not meet water-quality standards due 
to point and non-point sources of pollution are listed on EPA's 303(d) 
list of impaired water bodies. States must submit to EPA a 303(d) list 
(water-quality-limited waters) and a 305(b) report (status of the 
State's waters) every 2 years. IDEQ, under authority of the State 
Nutrient Management Act, is coordinating efforts to identify and 
quantify contributing sources of pollutants (including nutrient and 
sediment loading) to the Snake River basin via the Total Maximum Daily 
Load (TMDL) approach. In water bodies that are currently not meeting 
water-quality standards, the TMDL approach applies pollution-control 
strategies through several of the following programs: State 
Agricultural Water Quality Program, Clean Water Act section 401 
Certification, BLM Resource Management plans, the State Water Plan, and 
local ordinances. Several TMDLs have been approved by the USEPA in 
stream segments within the range of the Bliss Rapids snail in the Snake 
River or its tributaries (Buhidar 2006), although most apply only to 
TSS, TP, or temperature. Therefore, these stream segments do not yet 
have water quality attributes that are protective of the Bliss Rapids 
snail until the TMDL approach has sufficient time to bring the stream 
segment water quality in line with approved standards.
State Invertebrate Species Regulations
    There has been no change in State regulations regarding 
invertebrate protections since the time of listing. Take of Bliss 
Rapids snails is not regulated under Idaho State law.
Federal Consultation Regulations
    In Idaho, the USEPA retains authority for the issuance of permits 
through the NPDES, which is designed to manage point source discharges. 
There are presently more than 80 licensed aquaculture facilities on the 
Snake River permitted by the USEPA (USEPA 2002, pp. 4-19, 4-20). 
Updated draft permits for aquaculture and fish processing facilities 
throughout Idaho have recently been made available for public review 
(71 FR 35269). Draft permits have been issued for aquaculture 
facilities on Billingsley Creek, Riley Creek, Niagara Springs, and 
Thousands Springs, all within the known range of the Bliss Rapids 
snail. Facilities that produce less than 20,000 pounds (9,072 
kilograms) of fish annually are not required to obtain an NPDES permit 
(USEPA 2006, p. 3-1). These smaller facilities lie outside of this 
regulatory nexus, and as such their discharges are not regulated or 
reported.
    Since the species was listed in 1992, Federal agencies, including 
the Army Corps of Engineers and the FERC, have been required to comply 
with section 7

[[Page 47543]]

of the Act on any projects or managed activities that may affect the 
Bliss Rapids snail. If the species is delisted, terms and conditions 
now required of these agencies and their applicants to reduce the 
effects of their actions on the Bliss Rapids snail, such as placing 
conservation measures into agency permits, would not be required (e.g., 
see USFWS 2007). Currently, IPC and the Service are cooperating in a 
Settlement Agreement (Agreement) approved by the FERC. This Agreement 
was designed to assess potential effects of the IPC's operations in the 
Wiley and Dike Reaches, and was approved as part of the biological 
opinion and license issuance for the Lower Salmon Falls and Bliss 
Projects. These studies and their analyses are scheduled to be 
completed in 2009.
    The BLM manages more than 260 million acres of land in the 11 
western States, including land adjacent to the Snake River in Idaho. 
The BLM manages activities on Federal lands such as outdoor recreation, 
livestock grazing, mining development, and energy production to 
conserve natural, historical, cultural, and other resources on the 
public lands (USBLM 2006). In Idaho, the BLM has been consulting with 
the Service pursuant to section 7 of the Act on ongoing BLM actions 
that may affect the Bliss Rapids snail. Through these consultation 
efforts, coordinated and cooperative conservation measures have been 
added to proposed actions (e.g., new or renewed grazing permits on 
public lands) to minimize impacts to the species. Programmatic guidance 
and direction, documented through a conservation agreement between the 
BLM and Service, has increased the likelihood that conservation 
benefits may be realized for new, re-authorized, and ongoing actions; 
however, without the continued protections of the Act, there are no 
regulatory assurances that these conservation measures would continue.
    Summary of Factor D: While there are no specific State regulations 
protecting the Bliss Rapids snail, the primary threats identified in 
the final listing rule were related to the loss or alteration of the 
species' aquatic habitat. Regulatory mechanisms such as Idaho's water 
quality standards and TMDLs will continue to apply to habitats occupied 
by the Bliss Rapids snail. Water quality in some stretches of the Snake 
River has improved, primarily for phosphorus and TSS. New research 
indicates the species is sensitive to some aquatic contaminants such as 
copper, ammonia, and pentachlorophenol. Ground water withdrawal and the 
subsequent decline of the aquifer that feeds springs where the species 
occurs is a prominent threat. Depletion of cold water spring flows and 
declining ground water levels are a collective result of drought 
conditions, changes in irrigation practices, and ground water pumping. 
The effects of ground water pumping downstream in the aquifer can 
affect the upper reaches of the aquifer, and the effects of ground 
water pumping can continue for decades after pumping ceases. Thus, we 
anticipate ground water levels will likely continue to decline even if 
water conservation measures are implemented or are being developed. 
Some conservation benefits to the species are being realized through 
section 7 consultation with other Federal agencies, but without the 
Act's protection there are no regulatory assurances that these 
conservation benefits would continue. Based on this information, the 
inadequacy of existing regulatory mechanisms represents an ongoing 
threat to the Bliss Rapids snail that is likely to contribute to the 
species becoming endangered in the foreseeable future.

Factor E. Other Natural or Manmade Factors Affecting the Species' 
Continued Existence

    The final listing rule stated that New Zealand mudsnails 
(Potamopyrgus antipodarum) were not abundant in cold water springflows 
with colonies of Bliss Rapids snails, but that they did compete with 
the Bliss Rapids snail in the mainstem Snake River (57 FR 59254; 
December 14, 1992). We have no direct evidence that New Zealand 
mudsnails have displaced colonies of Bliss Rapids snails, but New 
Zealand mudsnails have been documented in dark mats at densities of 
nearly 400 individuals per square inch in free-flowing habitats within 
the range of the Bliss Rapids snail (57 FR 59254). Richards et al. 
(2006, pp. 61, 64, 68) found that Bliss Rapids snails may be 
competitively excluded by New Zealand mudsnails in most habitats, and 
that Bliss Rapids snail densities would likely be higher in the absence 
of New Zealand mudsnails. Both species are mostly scraper-grazers on 
algae and have similar resource requirements (Richards et al. 2006, pp. 
59, 66). Furthermore, New Zealand mudsnails have become established in 
every cold water spring-fed creek or tributary to the Hagerman Reach of 
the Snake River that has been surveyed (USFWS 2007). However, New 
Zealand mudsnails do not appear able to colonize headwater spring 
habitats, which may provide Bliss Rapids snails refugia from 
competition with New Zealand mudsnails (Frest and Johannes 1992, p. 50; 
Richards et al. 2006, pp. 67-68).
    The physiological tolerances of the New Zealand mudsnail, including 
temperature and water velocity (Winterbourn 1969, pp. 457, 458; Lysne 
and Koetsier 2006b, p. 81); life history attributes such as high 
fecundity and growth rates (Richards 2004, pp. 25-34); and wide variety 
of habitat use such as springs, rivers, reservoirs, and ditches (Cada 
2004, pp. 27, 28; USBR 2002, pp. 3, 11; Hall et al. 2003, pp. 407, 408; 
Clark et al. 2005, pp. 10, 32-35; Richards 2004, pp. 47-67), may 
provide the New Zealand mudsnail a competitive advantage over Bliss 
Rapids snails outside of cold headwater springs.
    Summary of Factor E: Studies since the time of listing indicate 
that competition for resources occurs between the New Zealand mudsnail 
and the Bliss Rapids snail due to similar life history requirements. 
The New Zealand mudsnail has become established and widely distributed 
in the Snake River and its tributaries, however we do not know what 
this expansion has done to the distribution and abundance of Bliss 
Rapids snails. The current information is inconclusive as to whether 
the New Zealand mudsnail presently endangers the Bliss Rapids snail, 
largely because Bliss Rapids snails appear to have refugia from 
competition with New Zealand mudsnails in headwater springs. However, 
the available evidence suggests that the New Zealand mudsnail may 
endanger the Bliss Rapids snail in the foreseeable future given 
projected declines in aquifer levels, which will likely cause the 
extirpation of Bliss Rapids snails from these refugia.

Conclusion

    In making a finding on whether or not a species warrants listing 
under the Act we must consider the legal definitions of ``endangered'' 
and ``threatened.'' A species is ``endangered'' for purposes of the Act 
if it is in danger of extinction throughout all or ``a significant 
portion of its range'' and is ``threatened'' if it is likely to become 
endangered within the foreseeable future throughout all or a 
significant portion of its range (emphasis added). The Act does not 
define the term ``foreseeable future.'' However, in a January 16, 2009 
memorandum addressed to the Acting Director of the U.S. Fish and 
Wildlife Service, the Office of the Solicitor, Department of the 
Interior, concluded, ``* * * as used in the [Act], Congress intended 
the term `foreseeable future' to describe the extent to which the 
Secretary can reasonably rely on

[[Page 47544]]

predictions about the future in making determinations about the future 
conservation status of the species.'' In considering the foreseeable 
future as it relates to the status of the Bliss Rapids snail, we 
considered the (1) biological and demographic characteristics of the 
species (such as habitat requirements (water depth, substrate, and 
temperature), spring vs. riverine colonies, and dispersal and 
recolonization ability), (2) our ability to predict or extrapolate the 
effects of threats facing the species into the future, and the (3) the 
relative permanency or irreversibility of these threats.
    The Bliss Rapids snail is a species endemic to Idaho and occurs 
primarily in cold water spring tributaries and the ground water 
influenced areas within the Snake River. Studies conducted since the 
species was listed in 1992 indicate that the species' overall 
geographic range has not substantially changed since it was first 
described by Hershler et al. (1994), but the species has been detected 
in more riverine, cold water springs, and spring tributary locations 
within its historical range. The Bliss Rapids snail has specific and 
rather narrow habitat requirements in the form of suitable substrate 
and water temperature.
    As discussed in the Summary of Factors section, we believe, based 
on the best available data, that it is reasonable to expect the primary 
threats (i.e., reduced ground water levels, water quality and pollution 
concerns, and competition from nonnative species) to Bliss Rapids 
snails will continue to occur throughout the range of the species and 
to affect all colonies into the future. Ground water levels are 
expected to continue to decline, resulting in increased risks to spring 
and spring-influenced colonies beginning at the upstream end of the 
species' range. Recent data show that spring colonies of Bliss Rapids 
snail contain rare alleles, and loss of such colonies are likely to 
reduce genetic diversity, which in turn reduces the species' ability to 
respond to changes in environmental conditions. If current ground water 
trends continue--and we have a reasonable expectation that they will 
based on the best available data--we expect some colonies to become 
extirpated as sites become unsuitable for Bliss Rapids snails due to 
reduced flows and degraded water quality. Loss of spring colonies is 
also likely to result in the loss of potentially important refugia from 
competition with the New Zealand mudsnail. Without the cold water 
spring refugia that provide stable environmental conditions (relative 
to riverine habitats), there is significant uncertainty regarding the 
ability of riverine populations to persist in the face of ongoing 
competition with New Zealand mudsnails. These uncertainties are 
exacerbated by existing hydropower operations that result in unknown 
levels of mortality to Bliss Rapids snails in the riverine environment, 
and the relatively low densities of Bliss Rapids snails in riverine 
habitats. Because of these significant uncertainties, if spring 
populations were lost due to groundwater depletion and/or changes to 
water quality in the springs, we would have little confidence that the 
Bliss Rapids snail could persist in the riverine environment alone.
    Therefore, we have determined that the Bliss Rapids snail is not 
now in danger of extinction, but is likely to become endangered in the 
foreseeable future based on the expected persistence of threats from 
reduced ground water levels, water quality and pollution concerns, and 
competition from nonnative species.

Significant Portion of the Range Analysis

    Having determined that the Bliss Rapids snail is likely to become 
endangered within the foreseeable future throughout all or a 
significant portion of its range, we must next consider whether there 
are any significant portions of its range that are currently in danger 
of extinction. The Act defines an endangered species as one ``in danger 
of extinction throughout all or a significant portion of its range,'' 
and a threatened species as one ``likely to become an endangered 
species within the foreseeable future throughout all or a significant 
portion of its range.'' The term ``significant portion of its range'' 
is not defined by statute. For purposes of this finding, a portion of a 
species' range is significant if it is part of the current range of the 
species and is important to the conservation of the species because it 
contributes meaningfully to the representation, resiliency, or 
redundancy of the species. The contribution must be at a level such 
that its loss would result in a decrease in the ability to conserve the 
species.
    The first step in determining whether a species is threatened or 
endangered in a significant portion of its range is to identify any 
portions of the range that warrant further consideration. The range of 
a species can theoretically be divided into portions in an infinite 
number of ways. However, there is no purpose to analyzing portions of 
the range that are not reasonably likely to be significant and 
threatened or endangered. To identify only those portions that warrant 
further consideration, we determine whether there is substantial 
information indicating that (1) the portions may be significant and (2) 
the species may be in danger of extinction there or likely to become so 
within the foreseeable future. In practice, a key part of this analysis 
is whether the threats are geographically concentrated in some way. If 
the threats to the species are essentially uniform throughout its 
range, no portion is likely to warrant further consideration. If any 
concentration of threats applies only to portions of the range that are 
unimportant to the conservation of the species, such portions will not 
warrant further consideration.
    If we identify any portions that warrant further consideration, we 
then determine whether in fact the species is threatened or endangered 
in any significant portion of its range. Depending on the biology of 
the species, its range, and the threats it faces, it may be more 
efficient in some cases for the Service to address the significance 
question first, and, in others, the status question first. Thus, if the 
Service determines that a portion of the range is not significant, the 
Service need not determine whether the species is threatened or 
endangered there; conversely, if the Service determines that the 
species is not threatened or endangered in a portion of its range, the 
Service need not determine if that portion is significant.
    If the Service determines that both a portion of the range of a 
species is significant and the species is threatened or endangered 
there, the Service will specify that portion of the range where the 
species is in danger of extinction pursuant to section 4(c)(1) of the 
Act.
    The terms ``resiliency,'' ``redundancy,'' and ``representation'' 
are intended to be indicators of the conservation value of portions of 
the species' range. Resiliency allows the species to recover from 
periodic disturbance. A species will likely be more resilient if large 
populations exist in high-quality habitat that is distributed 
throughout the range of the species in such a way as to capture the 
environmental variability within the range of the species. It is likely 
that the larger size of a population will help contribute to the 
viability of the species. Thus, a portion of the range of a species may 
make a meaningful contribution to the resiliency of the species if the 
area is relatively large and contains particularly high-quality habitat 
or if its location or characteristics make it less susceptible to 
certain threats than other portions of the range. When evaluating 
whether or how a portion of the range contributes to resiliency of the 
species, it may help to evaluate the historical

[[Page 47545]]

value of the portion and how frequently the portion is used by the 
species. In addition, the portion may contribute to resiliency for 
other reasons--for instance, it may contain an important concentration 
of certain types of habitat that are necessary for the species to carry 
out its life history functions, such as breeding, feeding, migration, 
dispersal, or wintering.
    Redundancy of populations may be needed to provide a margin of 
safety for the species to withstand catastrophic events. This does not 
mean that any portion that provides redundancy is a significant portion 
of the range of a species. The idea is to conserve enough areas of the 
range such that random perturbations in the system act on only a few 
populations. Therefore, each area must be examined based on whether 
that area provides an increment of redundancy that is important to the 
conservation of the species.
    Adequate representation insures that the species' adaptive 
capabilities are conserved. Specifically, the portion should be 
evaluated to see how it contributes to the genetic diversity of the 
species. The loss of genetic diversity may substantially reduce the 
ability of the species to respond and adapt to future environmental 
changes. A peripheral population may contribute meaningfully to 
representation if there is evidence that it provides genetic diversity 
due to its location on the margin of the species' habitat requirements.
    Based upon factors that contribute to our analysis of whether a 
species or subspecies is in danger of extinction throughout all or a 
significant portion of its range, and in consideration of the status 
of, and threats to, the Bliss Rapids snail discussed previously, we 
find that the primary threats to the continued existence of the Bliss 
Rapids snail occur throughout all of its range. Therefore, it is not 
necessary to conduct further analysis with respect to the significance 
of any portion of its range.

Finding

    On the basis of the best available scientific and commercial 
information, as discussed above, we find that the Bliss Rapids snail is 
likely to become endangered within the foreseeable future (i.e., it is 
threatened, as de