Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To Remove the Utah (Desert) Valvata Snail (Valvata utahensis) From the List of Endangered and Threatened Wildlife and Proposed Rule, 34539-34548 [E9-16837]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 74, Number 135 (Thursday, July 16, 2009)]
[Proposed Rules]
[Pages 34539-34548]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-16837]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FWS-R1-ES-2008-0084; 14420-1113-0000-C6]
RIN 1018-AW16


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To Remove the Utah (Desert) Valvata Snail (Valvata 
utahensis) From the List of Endangered and Threatened Wildlife and 
Proposed Rule

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notice of 12-month petition finding; proposed rule.

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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 Utah (desert) valvata 
snail (Valvata utahensis) 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 available scientific and commercial data, the Utah 
valvata snail is more widespread and occurs in a greater variety of 
habitats in the Snake River than known at the time of listing in 1992. 
We now know that the Utah valvata snail is not limited to areas of 
cold-water springs or spring outflows; rather, it persists in a variety 
of aquatic habitats, including cold-water springs, spring creeks and 
tributaries, the mainstem Snake River and associated tributary stream 
habitats, and reservoirs influenced by dam operations. Given our 
current understanding of the species' habitat requirements and threats, 
the species does not meet the definition of a threatened or endangered 
species under the Act. Therefore, we are proposing to remove the Utah 
valvata snail from the List, thereby removing all protections provided 
by the Act.

DATES: We will accept comments from all interested parties until 
September 14, 2009. We must receive requests for public hearings, in 
writing, at the address shown in the FOR FURTHER INFORMATION CONTACT 
section by August 31, 2009.

ADDRESSES: You may submit comments by one of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov. 
Follow the instructions for submitting comments.
     U.S. mail or hand-delivery: Public Comments Processing, 
Attn: RIN 1018-AW16, Division of Policy and Directives Management; U.S. 
Fish and Wildlife Service, 4401 N. Fairfax Drive, Suite 222, Arlington, 
VA 22203.
    We will not accept e-mail or faxes. We will post all comments on 
https://www.regulations.gov. This generally means that we will post any 
personal information you provide us (see the Public Comments Solicited 
section below for more information).

FOR FURTHER INFORMATION CONTACT: Jeffery L. Foss, State Supervisor, 
Idaho Fish and Wildlife Office, 1387 S. Vinnell Way, Room 368, Boise, 
ID 83709 (telephone 208/378-5243; facsimile 208/378-5262). Persons who 
use a telecommunications device for the deaf (TDD) may call the Federal 
Information Relay Service (FIRS) at 800/877-8339, 24 hours a day, 7 
days a week.

SUPPLEMENTARY INFORMATION: 

Public Comments Solicited

    Our intent is to use the best available commercial and scientific 
data as the foundation for all endangered and threatened species 
classification decisions. Comments or suggestions from the public, 
other concerned governmental agencies, the scientific community, 
industry, or any other interested party concerning this proposed rule 
to remove the Utah valvata snail from the List are hereby solicited. 
Comments particularly are sought concerning:
    (1) Additional information regarding the range, distribution, and 
population size of the Utah valvata snail, including the locations of 
any additional colonies or populations;
    (2) Data on any threats (or lack thereof) to the Utah valvata 
snail;
    (3) Current or planned activities in the areas occupied by the Utah 
valvata snail

[[Page 34540]]

and possible impacts of these activities on this species; and
    (4) Data on Utah valvata snail population trends.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in the ADDRESSES section. We will not 
accept comments sent by e-mail or fax or to an address not listed in 
the ADDRESSES section.
    We will post your entire comment--including your personal 
identifying information--on https://www.regulations.gov. If you provide 
personal identifying information in addition to the required items 
specified in the previous paragraph, such as your street address, phone 
number, or e-mail address, you may request at the top of your document 
that we withhold this information from public review. However, we 
cannot guarantee that we will be able to do so.
    Comments and materials we receive, as well as supporting 
documentation we used in preparing this proposed rule, will be 
available for public inspection on https://www.regulations.gov, or by 
appointment, during normal business hours at the Idaho Fish and 
Wildlife Office, 1387 S. Vinnell Way, Room 368, Boise, ID 83709; by 
telephone at 208/378-5243.

Public Hearing

    The Act provides for one or more public hearings on this proposal, 
if requested. Requests must be received by the date specified in the 
DATES section. Such requests must be made in writing and addressed to 
the State Supervisor (see FOR FURTHER INFORMATION CONTACT section 
above).

Species Information

    The Utah valvata snail (Valvata utahensis) was first recognized as 
a species in 1902 from specimens in Utah Lake and Bear Lake, Utah 
(Walker 1902, p. 125). Its common name has since been changed by the 
American Fisheries Society to the ``desert valvata'' in the benchmark 
text for aquatic invertebrate nomenclature, Common and Scientific Names 
of Aquatic Invertebrates from the United States and Canada (Turgeon et 
al. 1998, p. 109), presumably due to the fact that it is no longer 
known to occur in Utah. However, because the species is currently 
listed in the Code of Federal Regulations as the Utah valvata snail, 
Valvata utahensis will be referred to as the Utah valvata snail 
throughout this proposed rule.
    The Utah valvata snail is univoltine (produces one group of eggs 
per year) with a lifespan of about 1 year. Reproduction and spawning 
occur asynchronously between March and October, depending on habitat, 
with the majority of young spawned between August and October (Cleland 
1954, pp. 171-172; U.S. Bureau of Reclamation (USBR) 2003, p. 7). 
Emergence of a new cohort follows approximately 2 weeks after 
oviposition (Cleland 1954, p. 170; Dillon 2000, p. 103), and senescent 
snails (i.e., those approximately 374 days old) die shortly after 
reproduction (Cleland 1954, pp. 170-171; Lysne and Koetsier 2006a, p. 
287).
    Lysne and Koetsier (2006a, p. 288) determined the average size of 
adult Utah valvata snails to be 0.17 inches (4.32 millimeters (mm)). 
The Utah valvata snail has been observed to produce egg masses which 
contained 3 to 12 developing snails (Lysne and Koetsier 2006a, p. 288). 
Egg masses are approximately 0.39 to 0.06 inches (1.0 to 1.5 mm) in 
diameter, and young snails are approximately 0.03 inches (0.7 mm) in 
size upon emergence (Lysne and Koetsier 2006a, p. 289). Utah valvata 
snail young possess a turbinate shell form and an incipient carina 
(keel-shaped ridge) on the dorsal surface of the shell, which 
distinguishes them from the morphologically similar Valvata humeralis. 
Based on field and laboratory observations, the Utah valvata snail is 
primarily a grazer (Lysne and Koetsier 2006a, p. 287; Frest and 
Johannes 1992, pp. 13-14).

Range

    The Utah valvata snail, or at least its closely related ancestors, 
has been described as ranging widely across the western United States 
and Canada as far back as the Jurassic Period, 199.6  0.6 
to 145.5  4 million years ago (Taylor 1985a, p. 268). 
Fossils of the Utah valvata snail are known from Utah to California 
(Taylor 1985a, pp. 286-287). The Utah valvata snail was likely present 
in the ancestral Snake River as it flowed south from Idaho, through 
Nevada, and into northeastern California (Taylor 1985a, p. 303). The 
Snake River escaped to join the Columbia River Basin approximately 2 
million years ago (Hershler and Liu 2004, pp. 927-928).
    At the time of listing in 1992 (57 FR 59244, December 14, 1992) we 
reported the range of the Utah valvata snail as existing at a few 
springs and mainstem Snake River sites in the Hagerman Valley, Idaho 
(River Mile (RM) 585), a few sites above and below Minidoka Dam (RM 
675), and in the American Falls Dam tailwater near Eagle Rock damsite 
(RM 709). Surveys at the State of Idaho's Thousand Springs Preserve (RM 
585) indicated declining numbers of snails, with two colonies at or 
below 6,000 individuals (57 FR 59245).
    New data collected since the time of listing indicate that the 
range of the species is discontinuously distributed in at least 255 
miles (410 kilometers (km)) of the Snake River and some associated 
tributary streams, an increase of nearly 122 river miles (196 km) from 
the previously known range. Their current range in the Snake River 
extends from RM 585 near the Thousand Springs Preserve (Bean 2005), 
upstream to the confluence of the Henry's Fork with the Snake River (RM 
837; Fields 2005, p. 11). Colonies of the Utah valvata snail have been 
found in the Snake River near the towns of Firth (RM 777.5), Shelley 
(RM 784.6), Payne (RM 802.6), Roberts (RM 815), and in the Henrys Fork 
approximately 9.3 miles (15 km) upstream from its confluence with the 
Snake River (at Snake RM 832.3) (Gustafson 2003). Based on limited 
mollusk surveys, the species has not been found upstream from the 
described location on the Henry's Fork or in the South Fork of the 
Snake River. Tributary streams to the Snake River where Utah valvata 
snails have been collected include Box Canyon Creek (RM 588) (Taylor 
1985b, pp. 9-10), and at one location in the Big Wood River (WRM 35) 
(USBR 2003, p. 22). Big Wood River observations require further 
investigation and may be the result of seasonal transport of Utah 
valvata snails via irrigation canals that connect the Big Wood and 
Snake Rivers, or passive transport via waterfowl (Miller et al. 2006, 
p. 2371) between large bodies of water (i.e., reservoirs).

Habitat Use

    At the time of listing in 1992, the best available data indicated 
that Utah valvata snails ``characteristically require cold, fastwater, 
or lotic habitats * * * in deep pools adjacent to rapids or in 
perennial flowing waters associated with large spring complexes'' (57 
FR 59244, December 14, 1992). In numerous field studies conducted since 
then, the species has been collected at a wide range of depths, ranging 
from less than 3.2 feet (1 meter) (Stephenson and Bean 2003, pp. 98-99) 
to depths greater than 45 feet (14 meters) (USBR 2003, p. 20), and at 
temperatures between 37.4 and 75.2 degrees Fahrenheit (F) (4 to 24 
degrees Celsius (C)) (Lysne 2007; Gregg 2006).
    Recent work conducted by the Idaho Department of Fish and Game 
(IDFG) in the upper Snake River demonstrated that Utah valvata snail 
presence was positively correlated with water depth (up to 18.37 feet 
(5.6 meters)) and temperature (up to 63 degrees F (17.2

[[Page 34541]]

degrees C)) (Fields 2005, pp. 8-9), and Utah valvata snail density was 
positively correlated with macrophyte (a water plant large enough to be 
observed with the unaided eye) coverage, water depth, and temperature 
(Fields 2006, p. 6). Similarly, Hinson (2006, pp. 28-29) analyzed 
available data from several studies conducted by the USBR (2001-2004), 
Idaho Power Company (IPC) (1995-2002), IDFG, Idaho Transportation 
Department (2003-2004) and others, and demonstrated a positive 
relationship between Utah valvata snail presence and macrophytes, 
depth, and fine substrates. One study reported Utah valvata snails in 
organically enriched fine sediments with a heavy macrophyte community, 
downstream of an aquaculture facility (RM 588) (Hinson 2006, pp. 31-
32).
    Survey data and information reported since the time of listing 
demonstrate that the Utah valvata snail is able to live in reservoirs, 
which were previously thought to be unsuitable for the species (Frest 
and Johannes 1992, pp. 13-14; USBR 2002, pp. 8-9; Fields 2005, p. 16; 
Hinson 2006, pp. 23-33). We now know the Utah valvata snail persists in 
a variety of aquatic habitats, including cold-water springs, spring 
creeks and tributaries, the mainstem Snake River and associated 
tributary stream habitats, and reservoirs.
    Alterations of the Snake River, including the construction of dams 
and reservoir habitats, have changed fluvial processes resulting in the 
reduced likelihood of naturally high river flows or rapid changes in 
flows, and the retention of fine sediments (U.S. Environmental 
Protection Agency (USEPA) 2002, pp. 4.30-4.31), which may also increase 
potential habitat for the species (e.g., Lake Walcott and American 
Falls Reservoirs). Utah valvata snail surveys conducted downstream from 
American Falls Dam (RM 714.1) to Minidoka Dam (RM 674.5), from 1997 and 
2001-2007, consistently found Utah valvata snails on fine sediments 
within this 39-mile (62.9 km) river/reservoir reach of the Snake River 
(USBR 1997, p. 4; USBR 2003, p. 8; USBR 2004, p. 5; USBR 2005, p. 6; 
USBR 2007, pp. 9-11; USFWS 2005, p. 119). Surveys conducted downstream 
of Minidoka Dam (RM 674.5) to Lower Salmon Falls Dam (RM 573.0) have 
detected Utah valvata snails, including one record from the tailrace 
area of Minidoka Dam in 2001 (USFWS 2005, p. 120).
    In summary, based on available information, the Utah valvata snail 
is not as specialized in its habitat needs as we thought at the time of 
listing. In the Snake River, the species inhabits a diversity of 
aquatic habitats throughout its 255-mile (410 km) range, including 
cold-water springs, spring creeks and tributaries, mainstem and free-
flowing waters, reservoirs, and impounded reaches. The species occurs 
on a variety of substrate types including both fine sediments and more 
coarse substrates in areas both with and without macrophytes. It has 
been collected at water depths ranging from less than 3.2 feet (1 
meter) to greater than 45 feet (14 meters), and at water temperatures 
ranging from 37.4 to 75.2 degrees F (3 to 24 degrees C).

Population Density

    The density of Utah valvata snails at occupied sites can vary 
greatly. For example, at one cold-water spring site at the Thousand 
Springs Preserve, the average density in 2003 was 197 snails/square 
meter (m\2\) (ranging between 0 and 1,724 snails/m\2\) (Stephenson et 
al. 2004, p. 23). In the mainstem Snake River between American Falls 
Reservoir and Minidoka Dam in 2002, Utah valvata snail densities 
averaged 91 snails/m\2\ (ranging from 0 to 1,188 snails per m\2\), and 
in American Falls Reservoir densities averaged 50 snails/m\2\ (range 
unavailable) (USBR 2003, p. 20). Above American Falls Reservoir in the 
mainstem Snake River, Utah valvata snail densities at six sites 
averaged 117 snails/m\2\ (ranging from 0 to 1,716 snails/m\2\) (Fields 
2006, pp. 12-13).
    Within reservoirs, the proportional occurrence of snails is 
relatively high. For all field studies and surveys, the highest 
proportions of samples where Utah valvata snails are present have been 
collected in lower Lake Walcott Reservoir (USBR 2002, p. 5; USBR 2003, 
p. 6). For sample years 2001 to 2006, the relative proportion of 
samples containing Utah valvata snails ranged from 40 (in 2004) to 62 
(in 2002) percent of samples collected. Similarly, American Falls 
reservoir samples contain a high proportion of Utah valvata snails with 
21 (in 2001) to 33 (in 2003) percent in collections between 2002 
through 2004. Such high proportional occurrence in reservoirs is 
additional evidence that Utah valvata snails are not restricted to 
cold-water springs or their outflows.

Previous Federal Actions

    We listed the Utah valvata snail as endangered on December 14, 1992 
(57 FR 59244). Based on the best available data at that time we 
determined that the Utah valvata 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 Utah valvata snail. Critical habitat has not been 
designated for this species.
    On April 11, 2006, we initiated a 5-year review for the species in 
accordance with section 4(c)(2) of the Act (71 FR 18345). On December 
26, 2006, the Service received a petition from the Governor of Idaho 
and attorneys from several irrigation districts and canal districts 
requesting that the Utah valvata 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 Utah valvata 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 review (72 
FR 31264). As part of our best available scientific and commercial data 
analysis, we conducted a 30-day peer review on a draft status-review 
document, which was completed in September 2007 (USFWS 2007). The 
Summary of Factors Affecting the Species section below represents the 
best available scientific and commercial data resulting from our 
analysis and applicable updates from the previous peer review process.

Summary of Factors Affecting the Species

    Section 4 of the Act (16 U.S.C. 1533) 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. Changes in the List can be 
initiated by the Service or through the public petition process. 
Section 4 (b)(3)(A) of the Act (16 U.S.C. 1531 et seq.) requires that, 
for any petition containing substantial scientific and commercial 
information that listing 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 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) Present or

[[Page 34542]]

threatened destruction, modification, or curtailment of habitat or 
range; (B) overutilization for commercial, recreational, scientific, or 
educational purposes; (C) disease or predation; (D) 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; and/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.

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 Utah valvata as an endangered 
species, we stated: ``Six proposed hydroelectric projects, including 
two high dam facilities, would alter free-flowing river reaches within 
the existing range of [the Utah valvata snail]. Dam construction 
threatens the [Utah valvata 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 these snails'' (57 FR 
59251).
    Since the time of listing, proposed hydroelectric projects 
discussed in the 1992 final 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 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). Additionally, recent studies 
have shown that the Utah valvata snail is not as limited in its habitat 
needs as we had thought at the time of listing (see Species Information 
section above).
Operation of Existing Hydropower Dams
    In the 1992 final rule, we discussed 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, as a 
threat to the Utah valvata snail. Peak-loading was described as ``a 
frequent and sporadic practice that results in dewatering mollusk 
habitats in shallow, littoral shoreline areas'' (57 FR 59252). Studies 
conducted since the time of listing have shown the Utah valvata snail 
is able to persist in reservoirs, contrary to our understanding of the 
species at the time of listing (USFWS 2005, p. 105; 57 FR 59244, 
59245). For example, Lake Walcott (RM 702.5 to 673.5; upstream of 
Minidoka Dam) appears to contain the largest population of Utah valvata 
snails in the Snake River system (USFWS 2005, pp. 111-112). This is 
likely due to relatively good water quality in the reservoir compared 
to downstream sections of the Snake River near Hagerman where water 
quality is influenced by agricultural, municipal, and aquaculture flows 
into the river. In lower Lake Walcott, there is a large area of 
suitable Utah valvata snail habitat that remains submerged despite 
annual drawdowns (the reservoir fluctuates by no more than 5 feet (1.5 
meters) annually, thereby limiting the number of snails affected by 
dewatering and desiccation). Further, surveys conducted in the mainstem 
Snake River in 1997, 1998, and 2001, from American Falls Dam (RM 714.1) 
to Lake Walcott (RM 702.5) indicate a fairly large and viable 
population of Utah valvata snails even though shoreline habitats in 
this stretch undergo annual dewatering (USFWS 2005, p. 119). In 
American Falls reservoir, dam operations and fluctuating flows have 
been estimated to kill between 5 and 40 percent of the Utah valvata 
snails in most years. Nevertheless, Utah valvata snails continue to 
persist in these reservoirs with relatively high proportional 
occurrence (USFWS 2005, p. 119).
Degraded Water Quality
    In the final listing rule, we stated: ``The quality of water in 
[snail] habitats has a direct effect on the species [sic] survival. The 
[Utah valvata snail] require[s] cold, well-oxygenated unpolluted water 
for survival. Any factor that leads to deterioration in water quality 
would likely extirpate [the Utah valvata snail]'' (57 FR 59252). As 
described above in the Species Information section, our understanding 
of the species' habitat requirements has changed substantially since 
1992. Furthermore, new information has become available indicating both 
(a) improvements to Snake River water quality, and (b) the ability of 
Utah valvata snail to inhabit and persist in reaches of the Snake River 
rich in nutrients (e.g., nitrogen and phosphorus).
    Factors that are known to degrade water quality in the Snake River 
include reduced water flow, warming due to impoundments, and increases 
in the concentration of nutrients, sediment, and pollutants reaching 
the river from agricultural and aquaculture inputs (USFWS 2005, p. 
106). Several water-quality assessments have been completed for the 
Snake River by the USEPA, USBR, U.S. Geological Survey (USGS), and IPC. 
All of these assessments generally demonstrate that water quality in 
the Snake River of southern Idaho meets Idaho's water-quality criteria 
for the protection of aquatic life for some months of the year, but may 
be poor in reservoirs or during summer high temperatures and low flows, 
based on water-quality criteria such as dissolved oxygen (Clark et al. 
1998, pp. 20-21, 24-27; Clark et al. 2004, pp. 38-40; Clark and Ott 
1996, p. 553; Clark 1997, pp. 1-2, 19; Meitl 2002, p. 33).
    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, 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

[[Page 34543]]

generally warmer, contains pesticides or pesticide byproducts, has been 
enriched with nutrients from 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. 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. 42-45). Additionally, concentrations of lead, 
cadmium, and arsenic have been detected in snails collected from the 
Snake River (Richards 2003). 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).
    The effects of pollutants detected in the Snake River (e.g., 
metals, pesticides, excess nutrients) on the growth, reproduction, and 
survival of the Utah valvata snail have not been evaluated. However, 
the evidence available to us (including several intensive survey 
efforts) does not indicate that the population is declining or that the 
range of the species is contracting. Furthermore, the Utah valvata 
snail has been documented to occur in low-oxygen, organically-enriched 
sediments with heavy macrophyte communities downstream of an 
aquaculture facility (RM 588) (Hinson 2003, p. 17), indicating that the 
species may not be as sensitive to these pollutants as we once 
suspected. Based on the current best available information, we are not 
aware that water quality in the Snake River limits growth, 
reproduction, or survival of the Utah valvata snail in any portion of 
its range.
    There have been substantial declines in total dissolved solids 
(TSS) primarily as a result of changing irrigation practices. There 
have also been substantial declines in TP from changing agricultural 
practices and changing aquaculture feeds in the middle Snake River 
downstream of Lake Walcott. Data collected by the Idaho Department of 
Environmental Quality (IDEQ) show decreases of TSS near 64 percent 
compared to 1990 levels, and decreases of TP near 33 percent compared 
to 1990 levels (Buhidar 2006). The specific water-quality parameters 
required for the survival and persistence of the Utah valvata snails 
are not known. However, the Utah valvata snail occurs over a relatively 
large documented range of over 255 river miles (410 km) (USFWS 2005, 
pp. 110-113) and has the ability to tolerate and persist in a variety 
of aquatic habitats with some degree of water-quality degradation 
(Lysne and Koetsier 2006b, pp. 234-237). For example, studies conducted 
by the USBR in 2003 in Lake Walcott Reservoir indicated the highest 
Utah valvata snail densities occurred in the lower reservoir, where the 
sediments had the greatest percentage of organic content (an indicator 
that oxygen levels are likely low) (Hinson 2006, p. 19).
    Summary of Factor A: Our understanding of the habitat needs of the 
Utah valvata snail has changed substantially since the species was 
listed in 1992. Survey data collected since 1992 indicate that the 
geographic range of the species in the Snake River is approximately 122 
river miles (196 km) larger than known at the time of listing, that it 
occurs in a variety of substrate types (e.g., fines to cobble size) and 
flows, and that it tolerates a range of water-quality parameters. 
Threats pertaining to the construction of new hydropower dams as cited 
in the 1992 final rule have not been realized as the plans for dam 
construction have expired or been withdrawn. The operation of existing 
hydropower dams and reservoirs likely affect the distribution of the 
Utah valvata snail along the shoreline areas due to fluctuating flows 
and seasonal dewatering; however, the species appears to persist in 
these reservoirs with relatively high proportional occurrence. There is 
no information to suggest that degraded water quality is affecting the 
species' population numbers or distribution. Evidence indicates that 
improvements have been made in Snake River water-quality parameters 
including TSS and TP in some Snake River reaches since listing. 
Therefore, destruction, modification, or curtailment of the Utah 
valvata snail's habitat or range is not currently putting the species 
in danger of extinction, and is not likely to result in the 
endangerment or extinction of the species in the foreseeable future.

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

    Based on the best available scientific and commercial data, we 
believe that overutilization for commercial, recreational, scientific, 
or educational purposes is not currently putting the Utah valvata 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 limited in scope 
and extent. While collection could result in mortality of individuals 
within a small area, they are unlikely to have population-level effects 
because only a few individuals and institutions are interested in 
collecting the species and the life-history strategy of the species 
makes populations relatively resilient to limited mortality (i.e., 
invests little in reproduction, relatively high reproductive output 
(many eggs laid at a time), early age of reproduction, and short 
lifespan).

Factor C. Disease or Predation

    Parasitic trematodes similar to those of the genus Microphallus 
have been identified in some freshwater snails (e.g., Pyrgulopsis 
robusta) that share similar habitats in the Snake River in Idaho 
(Dybdahl et al. 2005, p. 8). However, the occurrence of trematode 
parasites on Utah valvata has not been studied.
    Predators of the Utah valvata snail have not been documented; 
however, we assume that some predation by native and non-native species 
occurs. Aquatic snails in general are prey for numerous invertebrates 
and vertebrates (Dillon 2000, pp. 274-304), and predation on other 
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; McCarthy and Fisher 2000, p. 387).
    Based on the best available scientific and commercial data, we 
believe that the threat of disease or predation is not placing the Utah 
valvata snail in danger of extinction, and is not likely to result in 
the endangerment or extinction of the species in the foreseeable 
future. The life-history strategy of the Utah valvata makes populations 
relatively resilient to limited mortality due to parasites or disease 
(i.e., invests little in reproduction, relatively high reproductive 
output (many eggs laid at a time), early age of reproduction, and short 
lifespan).

Factor D. Inadequacy of Existing Regulatory Mechanisms

    In the final listing rule, we found inadequate regulatory 
mechanisms to be a threat because: (1) Regulations were inadequate to 
curb further water withdrawal from groundwater spring outflows or 
tributary spring streams, (2) it was unlikely that pollution-control 
regulations would reverse the trend in nutrient loading any time soon, 
(3) there

[[Page 34544]]

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 
for unlisted snails. Below, we address each of these concerns in turn.
Groundwater Withdrawal Regulations
    Since 1992, new information has become available clarifying the 
habitat requirements of the Utah valvata snail. The species is not 
limited to cool, fast-water, or lotic habitats, or perennial flowing 
waters associated with large spring complexes, as previously believed. 
The species is able to live in a variety of aquatic habitats, and is 
locally abundant throughout a 255-mile (410 km) stretch of the Snake 
River in tributary streams, mainstem Snake River, and in reservoirs 
that are managed for annual drawdowns.
    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 Utah valvata 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., 
fish and wildlife, hydropower, or agriculture). Another IDWR regulatory 
mechanism is the ability of the Idaho Water Resource Board to 
appropriate water for minimum stream flows when in the public interest 
(IDWR 2006b).
    Since 1992, the IDWR and other State agencies have also created 
additional regulatory mechanisms that limit future surface and 
groundwater development, including the continuation of various 
moratoria on new consumptive water rights and the designation of Water 
Management Districts (Caswell 2007). The State is working with numerous 
interested parties to stabilize aquifer levels and enhance cold-water-
spring outflows from the Eastern Snake River Plains. The recently 
proposed Comprehensive Aquifer Management Plan (CAMP) for the Eastern 
Snake River Plains area identifies water conservation measures to be 
implemented (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) 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. Nevertheless, the extinction or 
endangerment of the Utah valvata snail is unlikely given its ability to 
survive and persist in a wide variety of aquatic habitats not dependent 
upon groundwater outflows.
Pollution Control Regulations
    Since 1992, reductions in sediment (TSS) and phosphorus (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 Utah 
valvata snail. These programs are tiered off of 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 two 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 EPA in stream 
segments within the range of the Utah valvata snail in the Snake River 
or its tributaries (Buhidar 2006), although most apply only to TSS, TP, 
or temperature.
State Invertebrate Species Regulations
    There are no State regulatory protections for the Utah valvata 
snail in Idaho. The primary threats to the species, as identified in 
our listing rule, were related to the loss or alteration of habitat. 
The lack of specific regulations protecting individual Utah valvata 
snails does not, by itself, imply that the species is threatened or 
endangered.
Federal Consultation Regulations
    The discussion regarding the lack of a Federal regulatory mechanism 
in the 1992 listing rule was primarily related

[[Page 34545]]

to the proposed construction of six dams within the range of the 
species coupled with our belief at the time of listing that the species 
required cold, fast-water, or lotic habitats. As stated above, dams are 
no longer being proposed for construction and our understanding of Utah 
valvata snail habitat requirements has changed. Thus, the importance of 
a regulatory mechanism to address these threats is no longer a 
significant issue with regard to the conservation of the Utah valvata 
snail.
    Summary of Factor D: Although there are no specific State 
regulations protecting the Utah valvata snail, the primary threats 
identified in the final listing rule were related to the loss or 
alteration of the species' habitat. Furthermore, as our understanding 
of the species' habitat requirements has changed, so has our 
understanding of the species' conservation and regulatory needs. 
Regulatory mechanisms such as Idaho's water-quality standards and TMDLs 
will continue to apply to habitats that the Utah valvata snails occupy 
should we finalize this delisting proposal. Therefore, the inadequacy 
of existing regulatory mechanisms does not presently endanger the Utah 
valvata snail, nor is it likely to do so 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 were not 
yet abundant in cold-water spring flows with colonies of the Utah 
valvata snail, but that they likely did compete with the species in the 
mainstem Snake River habitats (57 FR 59254). Surveys have found that 
Utah valvata snails and New Zealand mudsnails frequently co-occur in 
cold-water spring, mainstem Snake River, and reservoir habitats (37 
percent co-occurrence in combined habitat types), which may indicate 
that these two species are able to co-exist or that they actually have 
slightly different resource preferences (e.g., periphytic vs. 
perilithic algae) (Hinson 2006, p. 42). However, Hinson (2006, p. 41) 
also notes that the overlap in habitat utilization between the Utah 
valvata snail and the New Zealand mudsnail could lead to direct 
competition for resources between these two species.
    The USBR reported that New Zealand mudsnails are increasing in Lake 
Walcott, yet the densities observed were substantially lower than those 
observed in mainstem Snake River habitats downstream (USBR 2003, p. 19, 
USBR 2005, p. 6). Further upstream, the distribution of New Zealand 
mudsnails currently appears to be limited to the upper end of American 
Falls Reservoir near the input of the Snake and Portneuf rivers (USBR 
2003, p. 21). Surveys conducted even further upstream in the Snake 
River and tributaries (Field 2004, 2005, pp. 8-12) found moderate-to-
high densities of the New Zealand mudsnail at five sites. However, 
Field (2005, p. 10) stated that the current distribution of New Zealand 
mudsnails in the Snake River above American Falls Reservoir could more 
strongly reflect patterns of introductions rather than habitat 
preferences. Populations of the New Zealand mudsnail are not known to 
occur in the Wood River.
    Summary of Factor E: The New Zealand mudsnail frequently co-occurs 
with the Utah valvata snail and may be competing for habitat or food. 
The New Zealand mudsnail can reach extremely high densities in the 
middle Snake River (Richards et al. 2001, p. 375), and has been 
recorded at moderate-to-high densities at five sites in tributaries to 
the Snake River and the Snake River above American Falls Reservoir. 
Populations of the New Zealand mudsnail are not known to occur in the 
Wood River. The overall impact on the Utah valvata snail from the 
invasion of the New Zealand mudsnail is unknown (Lysne 2003, pp. 85-86; 
Hinson 2006, p. 41). However, after approximately 20 years of co-
occurrence there is no evidence suggesting that the New Zealand 
mudsnail has caused local extirpations of the Utah valvata snail. 
Although this does not rule out potential future effects to the Utah 
valvata snail's distribution or abundance, the current evidence does 
not support the conclusion that the New Zealand mudsnail presently 
endangers the Utah valvata snail, nor that it is likely to do so in the 
foreseeable future.

Foreseeable Future

    For the purposes of this proposed rule, the ``foreseeable future'' 
is the period of time over which events or effects reasonably can or 
should be anticipated, or trends reasonably extrapolated, such that 
reliable predictions can be made concerning the status of the species. 
As discussed above in the Summary of Factors section, we determined 
that the primary threats that were identified at the time the Utah 
valvata snail was listed in 1992 (construction of new, and operation of 
existing, hydropower dams; water quality and quantity; inadequacy of 
regulatory mechanisms; and the introduction of a new invasive snail 
(i.e., the New Zealand mudsnail)) no longer exist (e.g., new dams), 
have improved (e.g., water quality), or have not been as severe as 
expected (e.g., the New Zealand mudsnail). All indications, based on 
our improved understanding of the Utah valvata snail's range, habitat 
requirements, and ecology, suggest that the Utah valvata snail is more 
widely distributed and occurs in a variety of ecological settings over 
a 255-mile (410 km) range of the Snake River. Much of the Snake River 
within the range of the Utah valvata is influenced by seasonal dam 
operations for hydroelectric or agricultural purposes, yet the species 
persists in these varied mainstem Snake River systems, including 
impounded reservoir habitats (e.g., Lake Walcott and American Falls 
reservoirs). In short, given the available information, we can not 
reasonably predict or anticipate that threats to the Utah valvata snail 
will increase in severity in the future such that they would lead the 
species to become threatened or endangered throughout all or a 
significant portion of its range.

Conclusion of the Rangewide 5-Factor Analysis

    As required by the Act, we considered the five potential threat 
factors to assess whether the Utah valvata snail is threatened or 
endangered throughout its range (our analysis of whether there are 
significant portions of the species' range that are threatened or 
endangered follows this section). Information collected since the 
species' listing in 1992 indicates that the Utah valvata snail is 
widely distributed and occurs in a variety of ecological settings over 
a 255-mile range of the Snake River. Much of the Snake River within the 
range of the Utah valvata is influenced by seasonal dam operations for 
hydroelectric or agricultural purposes, yet the species persists in 
these varied mainstem Snake River systems, including impounded 
reservoir habitats (e.g., Lake Walcott and American Falls reservoirs). 
None of the threats that we identified in the 1992 listing appear to be 
significant to the species in light of our current understanding of its 
status. Nor have we identified any other threats to the species. 
Therefore, we find that the Utah valvata snail is not in danger of 
extinction throughout its range, nor is it likely to become so in the 
foreseeable future.
    The Service has determined that the original data for 
classification of the Utah valvata snail used in 1992 were in error. 
However, it is important to note that the original data for 
classification constituted the best available scientific and commercial 
data available at the time and were in error only in the sense that 
they were incomplete. The primary considerations for proposing to 
delist

[[Page 34546]]

the Utah valvata snail are described in the five-factor analysis above.

Significant Portion of the Range Analysis

    Having determined that the Utah valvata snail does not meet the 
definition of a threatened or endangered species throughout its range, 
we must next consider whether there are any significant portions of its 
range where it is in danger of extinction or is likely to become 
endangered in the foreseeable future. On March 16, 2007, a formal 
opinion was issued by the Solicitor of the Department of the Interior, 
``The Meaning of `In Danger of Extinction Throughout All or a 
Significant Portion of Its Range' '' (U.S. DOI 2007). We have 
summarized our interpretation of that opinion and the underlying 
statutory language below. 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 of the species 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 (i) the portions may be 
significant and (ii) 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. Moreover, 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 of a species' range 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.
    The terms ``resiliency,'' ``redundancy,'' and ``representation'' 
are intended to be indicators of the conservation value of portions of 
the species' range. Resiliency of a species 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 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 genetically based 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.
    Applying the process described above we evaluated a recent genetic 
study of the Utah valvata snail (Miller et al. 2006) and the ecological 
settings in which the species occurs throughout its range. We divided 
the range into three population units for further analysis: The Wood 
River population unit, the Snake River population unit, and the 
Hagerman population unit. Both the Wood River and Hagerman populations 
are separated geographically, and in the case of the Hagerman 
population, genetically and ecologically. Geographically, the Upper 
Snake and Henry's Fork Rivers and reservoirs of the Snake River are 
proximal and have a greater potential for connectivity of the Utah 
valvata snail populations in these reaches. They were analyzed as one 
unit: the Snake River population unit. We then evaluated whether each 
unit constitutes a significant portion of the range of the species, and 
if so, whether that portion was threatened or endangered.

Wood River Population Unit

    There is a high degree of uncertainty concerning the distribution 
and abundance of the species in the Wood River since there has been 
only one documented colony and systematic surveys have not been 
conducted. Based on the limited information we have on the Utah valvata 
snail in the Wood River, this colony does not appear to exist in an 
unusual or unique ecological setting or contain a large portion of the 
habitat or individuals (in fact, it appears to constitute an extremely 
small portion of the overall habitat and number of individuals). 
Further, recent genetic work conducted by Miller et al. (2006, pp. 
2367-2372) found that the Wood River occurrence is not genetically 
divergent or unique from the Snake River population unit. Because of 
genetic similarities between Utah valvata snails in the Snake River and 
Wood River units, the Wood River unit could provide some redundancy to 
the species if the Snake River unit (see below for further information) 
is extirpated by a catastrophic event. However, given that Utah valvata 
are distributed discontinuously along 255 miles (410 km) of the Snake 
River unit, a catastrophic event of the magnitude

[[Page 34547]]

necessary to simultaneously eliminate all Utah valvata colonies from 
the Snake River unite is highly unlikely. In addition, due to the 
geographic separation of the Wood River unit from the Snake River unit, 
it is unlikely that the Wood River unit would be a significant source 
of snails to recolonize the Snake River. Therefore, given these 
factors, we determined the Wood River population unit did not provide a 
significant contribution to the species with regard to redundancy, 
resiliency, and representation, and was not evaluated further.

Snake River Population Unit

    The Snake River population unit contains the largest and widest 
ranging portion of the overall Utah valvata snail population and 
contributes substantially to the resiliency, representation, and 
redundancy of the species. As mentioned above, the Snake River 
population was analyzed as one unit because the Upper Snake and Henry's 
Fork Rivers and reservoirs of the Snake River are proximal and have a 
greater potential for connectivity of the Utah valvata populations in 
these reaches. Other information contributing to its significance 
includes: (1) Additional surveys in this unit would likely find more 
colonies of Utah valvata snail, since most surveys conducted since 1992 
have been project based and systematic surveys have not yet occurred 
throughout much of this reach; (2) the uppermost reaches of the Snake 
River unit, including the Henry's Fork River where Utah valvata snail 
occurs, is not influenced by dam and other water management operations, 
and water quality is considered to be better than that found in the 
Wood River or Hagerman reaches further downstream in the Snake River; 
(3) Lower Lake Walcott Reservoir has high densities and high 
proportional occurrence of the Utah valvata snail and likely provides 
refugia for the species primarily due to the human-induced stability of 
this reservoir environment; and (4) genetically, the Snake River 
population unit represents the ancestral haplotypes of this species 
(Miller et al. 2006, p. 2368).
    For all of these reasons, we determined that the Snake River 
population unit of the Utah valvata snail constitutes a significant 
portion of the species' range. The Snake River population unit was then 
evaluated to determine if the Utah valvata snail is threatened or 
endangered in this portion of its range. This unit covers a wide 
geographic range and provides a wide variety of suitable habitats for 
Utah valvata snail in both reservoir and riverine reaches. This unit 
likely contains the largest number of individuals and colonies of the 
Utah valvata snail and would likely sustain the species into the 
foreseeable future independent of the other population units.
    Water quality is relatively good in the upstream (Henry's Fork) 
reaches of this unit compared to other population units, and the New 
Zealand mudsnail has not become established throughout this unit. 
Therefore, in the context of new information regarding the species' 
habitat and ecology, we likewise conclude that the Snake River 
population unit of Utah valvata snail is not threatened or endangered.

Hagerman Population Unit

    The best available data indicate that the Hagerman population unit 
is likely isolated and separated geographically from other Utah valvata 
snail colonies further upstream that constitute the Snake River 
population unit, but overall represents a small area of occupancy 
compared to the rest of the range of the species. The geographic 
isolation of the Hagerman population unit is an important 
consideration; the Miller et al. (2006) genetics paper suggests that 
Utah valvata snails found in cold-water spring outflows at the Thousand 
Springs Preserve may have been genetically isolated for over 10,000 
years and should be evaluated to determine if they can reproduce with 
other Utah valvata snails elsewhere in their range. This population 
unit also has a unique ecological setting compared to the other two 
units, as the species mainly occurs in tributary springs (and at their 
cold-water outflows), and not in reservoir or riverine habitats.
    In light of the above, we concluded that the Hagerman population 
unit may constitute a significant portion of the range of the Utah 
valvata snail. To determine if the Utah valvata snail is either 
threatened or endangered in this portion of the range, we evaluated the 
threat factors of water quality and effects, current hydropower 
operations, and the New Zealand mudsnail, and potential for other 
invasive species effects in the future.
    Currently, water quality is not considered to be a threat that is 
of high severity or magnitude to the Hagerman population unit for the 
reasons outlined in Factor A of the rangewide analysis. Furthermore, 
two cold-water spring outflows, Box Canyon and Thousand Springs, 
provide a relatively high-quality and stable aquatic environment for 
some Utah valvata snail colonies. Although flows have recently declined 
in some cold-water springs due to groundwater withdrawals, and water 
quantity and quantity could decrease over time if flows are not 
preserved, the Utah valvata snail would continue to persist in the 
mainstem Snake River in the Hagerman reach where it can tolerate 
variable water temperatures and water quality. Although there is 
evidence of some density-dependent effects and competition where the 
New Zealand mudsnail co-occurs with the Utah valvata snail, the Utah 
valvata snail continues to persist in these habitats. Despite 
approximately 20 years of co-occurrence of the New Zealand mudsnail and 
Utah valvata snail, there is no evidence suggesting that the New 
Zealand mudsnail has caused local extirpations of the Utah valvata 
snail in Hagerman reach. Therefore, we conclude that the Hagerman 
population unit of the Utah valvata snail is not threatened or 
endangered in this portion of its range.
    In summary, our understanding of the Utah valvata snail's habitat 
requirements, range, and threats has changed since the time of listing. 
From studies conducted since 1992, we now know that the species occurs 
over a much larger geographic range in the Snake River and is able to 
live in a variety of aquatic habitats and is not limited to cold, fast-
water, or lotic habitats, or in perennial flowing waters associated 
with large spring complexes as previously believed. In addition, the 
proposed construction of six new hydropower facilities as discussed at 
the time of listing is no longer a threat. The Utah valvata snail is 
now known to occur in, and persist in, aquatic habitats influenced by 
dam operations (e.g., reservoirs, and at elevated water temperatures), 
and the species co-exists in a variety of Snake River aquatic habitats 
with the invasive New Zealand mudsnail. We have determined that none of 
the existing or potential threats, either alone or in combination with 
others, are likely to cause the Utah valvata snail to become in danger 
of extinction within the foreseeable future throughout all or any 
significant portion of its range. The Utah valvata snail no longer 
requires the protection of the Act, and, therefore, we are proposing to 
remove it from the Federal List of Endangered and Threatened Wildlife.

Effects of This Rule

    If made final, this rule would revise 50 CFR 17.11(h) to remove the 
Utah valvata snail from the Federal List of Endangered and Threatened 
Wildlife. The prohibitions and conservation measures provided by the 
Act, particularly through sections 7 and 9, would no longer apply to 
this species.

[[Page 34548]]

Federal agencies would no longer be required to consult with the 
Service under section 7 of the Act in the event that activities they 
authorize, fun