Endangered and Threatened Wildlife and Plants; 12-Month Finding on a Petition To List the Nueces River and Plateau Shiners as Threatened or Endangered, 48777-48788 [2011-20054]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 76, Number 153 (Tuesday, August 9, 2011)]
[Proposed Rules]
[Pages 48777-48788]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-20054]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2011-0057; MO 92210-0-0008 B2]


Endangered and Threatened Wildlife and Plants; 12-Month Finding 
on a Petition To List the Nueces River and Plateau Shiners as 
Threatened or Endangered

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 list the Nueces River shiner 
(Cyprinella sp.) and plateau shiner (Cyprinella lepida) as threatened 
or endangered and to designate critical habitat under the Endangered 
Species Act of 1973, as amended (Act). After review of all available 
scientific and commercial information, we find that listing the Nueces 
River and plateau shiners is not warranted at this time. However, we 
ask the public to submit to us any new information that becomes 
available concerning the threats to the Nueces River and plateau 
shiners or their habitats at any time.

DATES: The finding announced in this document was made on August 9, 
2011.

ADDRESSES: This finding is available on the Internet at https://

[[Page 48778]]

www.regulations.gov at Docket Number [FWS-R2-ES-2011-0057]. Supporting 
documentation we used in preparing this finding is available for public 
inspection, by appointment, during normal business hours at the U.S. 
Fish and Wildlife Service, Austin Ecological Services Field Office, 
10711 Burnet Road, Suite 200, Austin, TX 78758. Please submit any new 
information, materials, comments, or questions concerning this finding 
to the above address.

FOR FURTHER INFORMATION CONTACT: Adam Zerrenner, Field Supervisor, 
Austin Ecological Services Field Office (see ADDRESSES); by telephone 
at 512-490-0057, extension 248; or by facsimile at 512-490-0974. If you 
use a telecommunications device for the deaf (TDD), please call the 
Federal Information Relay Service (FIRS) at 800-877-8339.

SUPPLEMENTARY INFORMATION:

Background

    Section 4(b)(3)(B) of the Endangered Species Act of 1973, as 
amended (Act) (16 U.S.C. 1531 et seq.), requires that, for any petition 
to revise the Federal Lists of Endangered and Threatened Wildlife and 
Plants that contains substantial scientific or commercial information 
that listing the species may be warranted, we make a finding within 12 
months of the date of receipt of the petition. In this finding, we will 
determine that the petitioned action is: (1) Not warranted, (2) 
warranted, or (3) warranted, but the immediate proposal of a regulation 
implementing the petitioned action is precluded by other pending 
proposals to determine whether species are threatened or endangered, 
and expeditious progress is being made to add or remove qualified 
species from the Federal Lists of Endangered and Threatened Wildlife 
and Plants. Section 4(b)(3)(C) of the Act requires that we treat a 
petition for which the requested action is found to be warranted but 
precluded as though resubmitted on the date of such finding, that is, 
requiring a subsequent finding to be made within 12 months. We must 
publish these 12-month findings in the Federal Register.

Previous Federal Actions

    On June 25, 2007, we received a petition dated June 18, 2007, from 
Forest Guardians (now WildEarth Guardians), requesting that 475 species 
in the southwestern United States, including the Nueces River and 
plateau shiners, be listed under the Act and critical habitat be 
designated. We acknowledged the receipt of the petition in a letter to 
the petitioner, dated July 11, 2007. In that letter we also stated that 
the petition was under review by staff in our Southwest Regional 
Office.
    On March 19, 2008, WildEarth Guardians filed a complaint alleging 
that the Service failed to comply with its mandatory duty to make a 
preliminary 90-day finding on the June 18, 2007, petition to list 475 
southwest species. We subsequently published an initial 90-day finding 
for 270 of the 475 petitioned species on January 6, 2009 (74 FR 419), 
concluding that the petition did not present substantial information 
that listing of those 270 species may be warranted. This initial 90-day 
finding did not include the Nueces River and plateau shiners. 
Subsequently, on March 13, 2009, the Service and WildEarth Guardians 
filed a stipulated settlement agreement, agreeing that the Service 
would submit to the Federal Register a finding as to whether their 
petition presented substantial information indicating that the 
petitioned action may be warranted for the remaining 192 southwestern 
species by December 9, 2009. On December 16, 2009 (74 FR 66866), we 
published a second 90-day finding for the remaining 192 southwestern 
species, which included a determination that listing the Nueces River 
and plateau shiners may be warranted, and initiated a status review. 
This notice constitutes the 12-month finding on the June 18, 2007, 
petition to list the Nueces River and plateau Shiners as threatened or 
endangered with critical habitat.

Species Information

Taxonomy and Species Description
    There has been some confusion and inconsistency regarding the 
taxonomy of the Nueces River and plateau shiners. Currently, there are 
approximately 30 species that belong to the genus Cyprinella, of which 
both species of shiners are members (Nelson et al. 2004, p. 69; 
Schonhuth and Mayden 2010, p. 77). The taxonomy within this genus has 
been associated with extensive confusion because similarities in body 
characteristics have made it difficult to differentiate between species 
(Schonhuth and Mayden 2010, p. 77). Fortunately, much of this confusion 
is being resolved with advances in genetic analysis (Schonhuth and 
Mayden 2010, pp. 77-98). However, there are still outstanding taxonomic 
issues that need to be resolved to clarify any potential confusion 
between the Nueces River and plateau shiners.
    When first described, the Nueces River and plateau shiners were not 
considered separate species. They were both originally described as the 
plateau shiner, Cyprinella lepida, by Girard in 1856 (Richardson and 
Gold 1995, p. 29). Nearly 100 years later, both species were still 
thought to be one species. For example, Hubbs (1954, pp. 277-291) 
recognized only one species as distinct, the plateau shiner, Notropis 
(=Cyprinella) lepidus, occurring in the Nueces, Frio, and upper 
Guadalupe Rivers. However, Mayden (1989, p. 60) later pointed out that 
the shiner Hubbs (1954, pp. 277-291) referred to in the upper Guadalupe 
River was actually a red shiner species, Notropis (=Cyprinella) 
lutrensis, and not the plateau shiner.
    Morphological studies conducted by Matthews (1987, pp. 616-637) and 
Mayden (1989, pp. 58-60) provided support that Cyprinella lepida was a 
distinct and valid species occurring in the Nueces, Frio, and Sabinal 
Rivers of the Nueces River basin (Figure 1). However, Matthews (1987, 
p. 269) noted that there were morphological differences between 
specimens collected in the Nueces and Frio Rivers, but did not suggest 
that there were two separate taxonomic entities. One of the main 
differences was breeding coloration in male specimens collected in the 
Frio River; these male specimens had red on the tip of their snouts 
(Matthews 1987, pp. 632-634). The male specimens collected in the 
Nueces River exhibited no breeding coloration (Matthews 1987, pp. 632-
634).

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[GRAPHIC] [TIFF OMITTED] TP09AU11.013

    These morphological differences between the Nueces and Frio Rivers' 
shiners were validated by genetic investigations that revealed two 
distinct lineages within populations of Cyprinella lepida. In 1987 and 
1988, Richardson and Gold (1995, p. 29) conducted a genetic study on 
Cyprinella lepida, in which they (Richardson and Gold 1995, p. 29) 
collected individuals from the Nueces, Frio, and Sabinal Rivers. The 
results of their genetic analysis showed that Cyprinella lepida in the 
Frio and Sabinal Rivers was a distinct species from Cyprinella lepida 
collected in the Nueces River (Richardson and Gold 1995, pp. 31-33). 
Specimens collected in the Frio River were very similar genetically to 
specimens collected in the Sabinal River (Richardson and Gold 1995, p. 
31). However, specimens collected from the Frio and Sabinal Rivers were 
quite different genetically from specimens collected in the Nueces 
River (Richardson and Gold 1995, p. 31). The genetic differences, along 
with the observed morphological differences, led Richardson and Gold 
(1995, pp. 31-33) to conclude that Cyprinella in the Frio and Sabinal 
Rivers was a distinct species from those in the Nueces River. Since 
1995, the population in the Nueces River has been referred to as the 
Nueces River shiner, an unnamed species within Cyprinella, while 
populations in the Frio and Sabinal Rivers have kept the kept the name 
plateau shiner, Cyprinella lepida. Formal naming of the Nueces River 
shiner, Cyprinella sp., is still pending.
    Further genetic investigations by Richardson and Gold (1999) 
supported their previous conclusion that Cyprinella in the Frio and 
Sabinal Rivers is a distinct species from those in the Nueces River. In 
this study, Richardson and Gold (1999, p. 50) focused on variation in 
mitochondrial genes in the five species of the shiner group inhabiting 
the southwestern United States, which included specimens of Cyprinella 
lepida from the Frio River and Cyprinella sp. from the Nueces River. 
Based on results of this study, Richardson and Gold (1999, p. 55) were 
hesitant to promote a sister relationship between the Nueces River 
shiner, Cyprinella sp., and the plateau shiner, Cyprinella lepida, 
meaning that the two lineages were not closely related. Instead, they 
concluded that the Nueces River shiner and plateau shiner were not as 
closely related to each other as they were to other species within the 
Cyprinella genus (Richardson and Gold 1999, p. 55).
    Another genetic study agreed that the Nueces River shiner and 
plateau shiner are distinct species. In 2000, Broughton and Gold (pp. 
1-10) conducted a genetic analysis of all Cyprinella species found

[[Page 48780]]

in the United States. As part of their methodology, Broughton and Gold 
(2000, p. 5) grouped the Nueces and Plateau shiners into the same 
species, Cyprinella lepida, but did make the distinction that 
``Cyprinella lepida-a'' from the Frio River were not closely related to 
``Cyprinella lepida-b'' from the Nueces River.
    In an effort to clarify some of the genus' taxonomic confusion, 
Schonhuth and Mayden (2010, pp. 77-98) conducted a genetic study of all 
species within the Cyprinella genus, with a more exhaustive focus on 
the problematic taxa. Results from Schonhuth and Mayden's (2010, p. 91) 
genetic analysis were consistent with previous genetic studies: 
Cyprinella lepida in the Sabinal and Frio Rivers are genetically 
separate and distinct from the Cyprinella sp. found in the Nueces 
River. Genetic differences between specimens from the Sabinal and Frio 
Rivers were very different from those collected in the Nueces River, 
enough so that Schonhuth and Mayden (2010, p. 91) recommended leaving 
them as separate species.
    Despite the morphological and genetic studies of the Nueces River 
and plateau shiners, the scientific community has been inconsistent in 
recognizing these shiners as separate species. The Texas Parks and 
Wildlife Department (TPWD) recognizes the plateau shiner (Cyprinella 
lepida) and Nueces River shiner (Cyprinella sp.) as separate species 
(Norris et al. 2005, p. 10). However, Phillips et al. (2010, p. 130) 
failed to recognize the Nueces River shiner as a separate species 
during a study on sound production and spawning behavior. In fact, 
Phillips et al. (2010, p. 130) stated that they collected Cyprinella 
lepida with seines from the Nueces River 0.5 mi (0.8 km) west of Camp 
Wood, Real County, Texas, during December 2002 and March 2003, and 
transferred them to a lab to do an acoustic study on spawning behavior. 
It is not clear whether Phillips et al. (2010) collected actual plateau 
shiners from the Nueces River, or whether they collected Nueces River 
shiners but mistakenly called them plateau shiners. Phillips et al. 
(2010) did not mention the name Nueces River shiner, Cyprinella sp., 
nor did they mention how they determined that the fish were Cyprinella 
lepida. To add further confusion, acceptance of the Nueces River 
shiner, Cyprinella sp., as a separate species from the plateau shiner, 
Cyprinella lepida, by the American Fisheries Society (2004, p. 69) is 
still pending. On the other hand, Hubbs et al. (2008, p. 19) recognized 
the Nueces River and plateau shiners as separate species in their 
annotated checklist of the freshwater fishes of Texas. Because there is 
still inconsistency, a formal systematic description by the scientific 
community of the Nueces River shiner, Cyprinella sp., is needed.
    Based on the best available science, we accept the characterization 
of the Nueces River shiner, Cyprinella sp., and the plateau shiner, 
Cyprinella lepida, as separate species. We base this distinction on the 
morphological and genetic research conducted by Richardson and Gold 
(1995, pp. 28-37), Edwards et al. (2008, pp. 1-30), and Schonhuth and 
Mayden (2010, pp. 77-98), and due to the fact that this research has 
been accepted by much of the scientific community (Hubbs et al. 2008, 
p. 19). However, we recognize there is a need for more extensive 
morphological, genetic, and life history research with more thorough 
species characterizations and formal descriptions of these two shiners, 
especially for the Nueces River shiner. Because we recognize these two 
shiners as separate species, we conduct separate five-factor analyses 
below under section 4(a)(1) of the Act to determine whether either 
species meets the definition of threatened or endangered. However, we 
address both species in this finding because they occur in nearby 
watersheds and could be subject to the similar threats.
Distribution
    Because of the inconsistencies in taxonomy and species descriptions 
of the Nueces River and plateau shiners, there has been similar 
confusion and inconsistencies regarding these shiners' distribution. 
However, one thing that has been clearly understood is that both the 
historic and current range of both shiners is the uppermost headwaters 
of the Nueces, Frio, and Sabinal Rivers of the Nueces River basin 
(Figure 1). The Nueces River basin covers approximately 17,000 square 
miles (44,030 square kilometers), encompassing all or part of 23 
counties in south-central Texas (Nueces River Authority 2010, p. 1). 
Rivers within the basin include Nueces, Frio, Leona, Sabinal, and 
Atascosa Rivers (Nueces River Authority 2010, p. 1). Because the Nueces 
River basin is so large, running from the Edwards Plateau region of 
Texas to the Gulf Coast of Mexico, there are large physical and 
chemical differences between streams in the upper and lower parts of 
the basin (Norris et al. 2005, p. 1; Nueces River Authority 2010, p. 
1). The differences between the upper and lower parts may be why the 
Nueces River and plateau shiners are only found in the upper, cooler 
headwaters.
    The upper Nueces River basin, where the Nueces River and plateau 
shiners are found, is composed of three main tributary systems: The 
Nueces, Frio, and Sabinal Rivers (Edwards et al. 2008, p. 2). The 
plateau shiner is an endemic (native to and generally confined to a 
particular region) minnow that inhabits clear, spring-fed streams over 
gravel limestone substrates in the uppermost headwaters of the Frio and 
Sabinal Rivers on the Edwards Plateau (Edwards et al. 2004, p. 261; 
Edwards et al. 2008, p. 2; Hubbs et al. 2008, p. 19). Meanwhile, the 
Nueces River shiner is an endemic minnow that is only found in the 
uppermost headwaters of the Nueces River, which is also on the Edwards 
Plateau (Edwards et al. 2004, p. 261; Hubbs et al. 2008, p. 19).
    An example of the inconsistency in the species' distribution 
occurred when TPWD associated the plateau and Nueces River shiners with 
the wrong stream segments in their 2005 designation of ecologically 
significant stream segments, which are stream segments designated based 
on factors related to biological function, hydrologic function, 
presence of riparian conservation areas, high water quality, 
exceptional aquatic life, high aesthetic value, threatened or 
endangered species, and uniqueness (Norris et al. 2005, pp. 16-19). 
Norris et al. (2005, pp. 16-19) stated that the Nueces River shiner 
occurred in the Frio and Sabinal River, and the plateau shiner occurred 
in the Nueces River (p. 17). However, this inconsistency may have 
occurred because of the confusion associated with the species' 
taxonomy, even though TPWD recognized the Nueces River and plateau 
shiners as two separate species (Norris et al. 2005, p. 10).
    In a recent study, Edwards et al. (2008, p. 3) attempted to 
estimate the current distributional range of plateau shiner in the Frio 
and Sabinal Rivers, and Nueces River shiner in the Nueces River. During 
their seasonal sampling from 2007 to 2008, Edwards et al. (2008, p. 5) 
captured over 11,700 individuals of 24 species, including the Nueces 
River and plateau shiners. They noted that the Frio, Sabinal, and 
Nueces Rivers were all dominated by fishes that are typical of spring-
fed headwater central Texas streams, but added that there is still 
incomplete knowledge of the current range of the plateau shiner in the 
Frio and Sabinal Rivers, and of the Nueces River shiner in the upper 
Nueces River (Edwards et al. 2008, p. 3). Based on the best available 
information, we believe that the Nueces River and

[[Page 48781]]

plateau shiners' historical and current ranges are the uppermost 
headwaters of the Sabinal, Frio, and Nueces Rivers in the Edwards 
Plateau region of Texas, but the extent of their ranges remains to be 
determined.
Habitat
    There is limited information in the literature regarding the Nueces 
River and plateau shiners' habitat. Edwards et al. (2004, p. 261) noted 
that the plateau shiner inhabited clear, spring-fed streams over gravel 
limestone substrates. Phillips et al. (2010, p. 133) noted that 
Cyprinella collected out of the Nueces River in 2002 and 2004 were 
crevice spawners (females release their eggs in crevices), like the 
majority of other Cyprinella species. Also, Phillips et al. (2010, p. 
133) noted that the specimens they collected relied on spring or 
spring-fed water. Although not specified to species, we assume that the 
Cyprinella Phillips et al. (2010, p. 133) referred to were Nueces River 
shiners based on where the specimens were collected. In any case, it is 
apparent that both shiners' habitat is spring-fed streams, which are 
typically found in the headwaters. Furthermore, the headwater streams 
where both Nueces River and plateau shiners occur are characterized by 
limestone bedrock with significant gravel and cobble bottoms, clear 
evidence of spring-flows with emergent vegetation and relatively 
shallow depths, relatively high pH values typical of limestone bedrock 
streams of the Edwards Plateau, relatively stable water temperatures, 
and dissolved oxygen levels generally around 10 parts per million 
(Edwards et al. 2008, p. 21). Though limited, this information is 
consistent with what is known about the shiners' habitat.
Population Abundance
    There has been much speculation and very little research actually 
surveying and documenting the abundance of the Nueces River and plateau 
shiners. A genetic study by Richardson and Gold (1995, p. 35) noted 
that the plateau shiner's abundance appeared to have decreased 
considerably over the previous 20 years prior to their study. However, 
their note of plateau shiner abundance was not based on actual surveys 
or data collection (Richardson and Gold 1995, p. 35). Also, we could 
not find any evidence or documentation that either of these shiners' 
abundance actually declined over this time period. Therefore, we cannot 
conclude that there was a decline in the Nueces River or plateau 
shiners over the 20 years prior to Richardson and Gold's (1995) study.
    Because of Richardson and Gold's (1995, p. 35) statement regarding 
the presumed decline of the two shiners, other researchers cited 
Richardson and Gold while making the same conjecture. For example, 
Hoagstrom et al. (2011, p. 24) claimed that 41 endemic fishes, 
including plateau and Nueces River shiners, were declining in the 
plains of North America because of dewatering, low flows, habitat 
fragmentation, nonnative species, and pollution. However, this 
presumption was based on the Richardson and Gold (1995) genetic study 
discussed above rather than on actual abundance data or surveys.
    There has been a noted decline throughout Texas for many of the 
State's native fishes (Hubbs et al. 2008, p. 2). Nonnative species, as 
well as degradation of water and habitat quality, are thought to be 
major components of the native fishes' decline (Hubbs et al. 2008, p. 
5). As part of the annotated checklist of the freshwater fishes of 
Texas, Hubbs et al. (2008, p. 19) identified both the Nueces River and 
plateau shiners as species of special concern. Hubbs et al. (2008, p. 
5) defined a species of ``special concern'' as a taxon whose abundance 
or range has been reduced to the degree that it may be threatened with 
extinction or whose range is only peripherally in Texas and could be 
easily extirpated. Some species were included in this category of 
special concern because up-to-date information concerning their status 
was unavailable or fragmentary (Hubbs et al. 2008, p. 5). In any case, 
Hubbs et al. (2008) provided no evidence for categorizing the Nueces 
River and plateau shiners as species of special concern. There was no 
supporting information on abundance, range reduction, or any other 
reason for classifying these two fishes as species of special concern. 
Therefore, it is reasonable to assume that Hubbs et al. (2008) 
classified the Nueces River and plateau shiners as a species of special 
concern because there was no up-to-date information concerning their 
status.
    Contrary to the information above, other studies have noted that 
the Nueces River and plateau shiners were abundant within the past 
decade in the headwaters of the Sabinal, Frio, and Nueces Rivers 
(Figure 1). In fact, Edwards et al. (2004, p. 261) stated that the 
plateau shiner was moderately abundant in the Edwards Plateau region. 
To obtain a more thorough assessment on the status of the Nueces River 
and plateau shiners, Edwards et al. (2008, p. 6) conducted a sampling 
study from 2007 to 2008 in the Nueces, Frio, and Sabinal Rivers and 
found that the Nueces River and plateau shiners were two of the most 
abundant fishes in each of these rivers out of 21 different species 
collected.
    Even though there have been claims in the scientific literature 
that the Nueces River and plateau shiners were declining, these claims 
appear to be unsubstantiated by actual survey data. On the other hand, 
a recent study conducted by Edwards et al. (2008, pp. 1-30) that 
surveyed abundance of the Nueces River and plateau shiners found large 
numbers of these species. In conclusion, there is insufficient evidence 
to determine population trends for either species.

Summary of Information Pertaining to the Five Factors

    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 Lists of 
Endangered and Threatened Wildlife and Plants. Under section 4(a)(1) of 
the Act, a species may be determined to be endangered or threatened 
based on any of the following five factors:
    (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range;
    (B) Overutilization for commercial, recreational, scientific, or 
educational purposes;
    (C) Disease or predation;
    (D) The inadequacy of existing regulatory mechanisms; or
    (E) Other natural or manmade factors affecting its continued 
existence.
    In making this finding, information pertaining to the Nueces River 
and plateau shiners in relation to the five factors provided in section 
4(a)(1) of the Act is discussed below. In making our 12-month finding 
on the petition, we considered and evaluated the best available 
scientific and commercial information. We reviewed the petition, 
information available in our files, and other available published and 
unpublished information. We also consulted with recognized fish experts 
and biologists with TPWD and The Nature Conservancy.

Summary of Information Pertaining to the Five Factors for Nueces River 
Shiner

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

    The following factors have the potential to affect the habitat or 
range of the Nueces River shiner: Livestock grazing, water quantity, 
water quality,

[[Page 48782]]

and land use. Below, we discuss in detail each of these factors and 
determine whether or not they constitute a threat to the species.
Livestock Grazing
    While we know that livestock grazing occurs within the range of the 
species, we could find no information on the extent or intensity of 
historical or current livestock grazing practices or the impact grazing 
might have on the Nueces River shiner and its habitat. In areas where 
livestock are grazed inappropriately, impacts could include, but are 
not limited to, runoff from disturbed stream banks, livestock urine and 
manure deposited into streams, disturbance and erosion from trampled 
banks, and increased solar exposure due to reduced shade from 
streamside vegetation and loss of undercut streambanks. Any of these 
impacts could affect the Nueces River shiner by degrading water quality 
and negatively impacting the species. Richardson and Gold (1995, p. 35) 
concluded that much of the land in the Nueces River basin is used for 
agriculture, and that overgrazing by cattle posed serious problems for 
aquatic fauna. However, we found no monitoring data indicating that 
water quality degradation associated with livestock grazing is 
occurring within the range of the Nueces River shiner. Based on the 
best available information, we could find no evidence that overgrazing 
is posing a threat to the Nueces River shiner or is likely to in the 
future. Therefore, because the best available information does not 
indicate that livestock grazing is negatively impacting the species, we 
find that the Nueces River shiner is not in danger of extinction now or 
in the foreseeable future as a result of livestock grazing.
Water Quantity
    Diminished water flows can cause losses in habitat diversity, 
reduce stream productivity, and degrade water quality for many fish 
species (Norris et al. 2005, p. 1). Richardson and Gold (1995, p. 35) 
suggested that groundwater (underground aquifer) levels for much of 
south-central Texas had decreased substantially over the decade 
preceding their study (1980s), resulting in significantly reduced water 
flow in spring-fed rivers, including the habitat of the Nueces River 
shiner. Although there is evidence of stream flow fluctuations that 
most likely relate to annual rainfall events, the best available 
information does not indicate that reduced stream flows are occurring 
within the range of the Nueces River shiner at a level that may 
adversely impact the species. As we have noted previously, the Nueces 
River shiner is an endemic minnow that is only found in the uppermost 
headwaters of the Nueces River within the Edwards Plateau (Edwards et 
al. 2004, p. 261; Hubbs et al. 2008, p. 19). Over the past century in 
the Edwards Plateau region of Texas, there has been evidence of some 
loss of natural spring and headwater stream flows (Edwards et al. 2004, 
p. 253). Yet, water users in the Edwards Plateau are altering their 
usage of waters from the aquifers of the Edwards Plateau. Reduced water 
usage has allowed for the conservation of regional spring flows 
(Edwards et al. 2004, p. 263). Additionally, stream flow monitoring is 
occurring at various sites within the Nueces River shiner's range by 
the United States Geological Survey (Edwards et al. 2008, p. 25), and 
Edwards et al. (2008, p. 25) analyzed these stream flow measurements in 
the Frio, Sabinal, and Nueces Rivers for the last decade. Results of 
Edward's et al. (2008, p. 25) analysis showed that there was a normal 
range of flow variation in each of the streams due to natural rainfall 
events. Edwards et al. (2008, p. 6) also noted that the Nueces River 
shiner was one of the most abundant fishes in the upper stream segments 
of the Nueces River. Thus, the stream flow variation was occurring at a 
level that had no known impact on the species. While there may be 
fluctuations in stream flow, there is no evidence indicating that 
reduced water flow is a threat to the species either now or in the 
foreseeable future. Therefore, we find that the Nueces River shiner is 
not in danger of extinction now or in the foreseeable future as a 
result of reduced water flow.
Water Quality
    Within the last 12 years, there has been cause for concern along 
certain stream segments of the Nueces River. In 1999, a 91-mile (mi) 
(147-kilometers (km)) stream segment of Nueces River that flows from 
Holland Dam in La Salle County to its confluence with the Frio River at 
the Choke Canyon Reservoir in Live Oak County was included in the State 
of Texas' Clean Water Act 303(d) list as impaired due to concentrations 
of dissolved oxygen below the minimum standards criteria in the lower 
25-mi (40-km) portion of the stream (Bonner et al. 2005, p. 1; Nueces 
River Authority 2010, p. 13). Adequate dissolved oxygen is necessary 
for respiration and other essential processes of aquatic organisms; 
thus, low levels may be detrimental to the health of aquatic organisms. 
The majority of this lower 25-mi (40-km) portion of the stream occurs 
in McMullen County, which lies in the South Texas Brush Country region 
of Texas, well outside the historical and current range of the Nueces 
River shiner. As noted above in the Species Information section, the 
Nueces River shiner's range occurs in the uppermost headwaters in the 
Edwards Plateau region of Texas. Therefore, the concerns about low 
dissolved oxygen content associated with this segment of Nueces River 
do not relate to the Nueces River shiner or its range.
    Based on the best available scientific and commercial information, 
there is no evidence that pollution causing diminished water quality 
may be having an impact on the Nueces River shiner or its habitat. In 
2005, the TPWD reported the Nueces River as having high water quality 
and exceptional aquatic life (Norris et al. 2005, p. 17). Also, the 
TPWD designated stream segments in the upper Nueces River as 
ecologically significant based on low levels of development in the 
watershed, no point sources of pollution, no channelization, and no 
atypical nonpoint sources of pollution (Norris et al. 2005, p. 5). 
Furthermore, water quality monitoring has been conducted in the 
uppermost reaches of the Nueces River where the majority of Nueces 
River shiners occur, and no problems have been found (Nueces River 
Authority 2010, p. 17). Therefore, we find that the Nueces River shiner 
is not in danger of extinction now or in the foreseeable future as a 
result of diminished water quality caused by pollution.
Land Use
    The decline of native fishes in the southern United States 
generally is attributable to pervasive, complex habitat degradation 
across the landscape that both reduces and fragments habitat and 
increases isolation of fish populations (Warren et al. 2000, p. 8). 
Often, physical habitat alteration in the form of channelization, 
impoundment, sedimentation, and flow modification are frequently 
associated with fish declines (Warren et al. 2000, p. 8).
    Edwards et al. (2008, p. 3) mentioned potential impacts to the 
Nueces River from existing agricultural practices, land use changes, 
and groundwater pumping, and stated that these have combined to create 
stream segments identified as impaired under section 303(d) of the 
Clean Water Act. One of the main purposes of the Edwards et al. (2008, 
p. 3) study was to find out if these potential impacts may actually be 
a factor in population and range declines among native fishes, 
including the Nueces River shiner. In order to determine the extent of 
these potential

[[Page 48783]]

impacts, Edwards et al. (2008, p. 27) looked at the biological 
integrity of streams in the upper Nueces River and found that the 
Nueces River had high water quality within the range of the Nueces 
River shiner. Also, Edwards et al. (2008, p. 29) noted that the fish 
fauna sampled are typically associated with high-quality spring-fed 
streams within the southern Edwards Plateau. On the other hand, Edwards 
et al. (2008, p. 27) noted some impacts along the upper Nueces River, 
such as development along the watercourse and recreational pressures 
during the summer months. Even with these impacts, the headwater 
streams of the Nueces River basin maintained much of their integrity as 
evidenced by such fish as the Nueces River shiner (Edwards et al. 2008, 
p. 27). In fact, Edwards et al. (2008, p. 6) stated that the Nueces 
River shiner was one of the most abundant fishes in the upper stream 
segments of the Nueces River. Further, The Nature Conservancy of Texas 
is currently engaged in watershed protection in the upper Nueces River 
basin, mainly as a participant in the City of San Antonio's Aquifer 
Protection Program (Edwards et al. 2008, p. 3). The Nature Conservancy 
holds several conservation easements and is exploring ways to increase 
conservation efforts in this part of the river basin (Edwards et al. 
2008, p. 3). Therefore, we find no evidence indicating that land uses 
are negatively impacting the Nueces River shiner now or in the 
foreseeable future.
Summary of Factor A
    We relied on the best available scientific and commercial 
information, which does not indicate that these or any factors are 
impacting the Nueces River shiner at a level that may impact the 
species. Therefore, we find that the Nueces River shiner is not in 
danger of extinction now or in the foreseeable future as a result of 
destruction, modification, or curtailment of its habitat or range.

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

    Based on the best available scientific and commercial information, 
there is no evidence that impacts are occurring to the Nueces River 
shiner or its habitat under this factor. Other than the scientific 
studies referenced in this finding, this shiner is not used for any 
commercial, recreational, or educational purposes. Therefore, we find 
that the Nueces River shiner is not in danger of extinction now or in 
the foreseeable future as a result of overutilization for commercial, 
recreational, scientific, or educational purposes.

Factor C. Disease or Predation

    We are not aware of any research that has been conducted to examine 
disease or predation in the Nueces River shiner. Also, we are not aware 
of any nonnative species that may prey on the Nueces River shiner. 
Therefore, based on the best available scientific and commercial 
information, we find that the Nueces River shiner is not in danger of 
extinction now or in the foreseeable future as a result of disease or 
predation.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    To determine if existing regulatory mechanisms are adequate to 
protect the Nueces River shiner, we evaluated agreements and laws in 
effect within the range of the species. One regulatory mechanism is the 
Clean Water Act (CWA), which was established in 1972. The CWA is the 
primary Federal law addressing water pollution in the United States. 
The purpose of the CWA is to stop pollutants from being discharged into 
waterways and to maintain water quality to provide a safe environment 
for fishing, swimming, and drinking. All navigable waters in the United 
States are covered under the CWA. The CWA provides guidelines and 
offers Federal financial assistance for identifying the causes of 
pollution. There are standards and regulations that must be adhered to 
by industries that discharge into waterways. The CWA sets forth water 
quality standards that are site-specific allowable pollutant levels for 
individual water bodies, such as rivers, lakes, streams, and wetlands. 
State agencies are required by the CWA to set water quality standards 
by designating uses for the water body (e.g., recreation, water supply, 
aquatic life, and agriculture) and applying water quality criteria to 
protect the designated uses.
    In Texas, the Texas Commission on Environmental Quality (TCEQ), 
formerly known as Texas Natural Resource Conservation Commission, is 
the environmental agency that oversees water quality standards as 
required by the CWA (TCEQ 2010b, p. 19). The TCEQ strives to protect 
Texas' human and natural resources consistent with sustainable economic 
development, by providing clean air, clean water, and the safe 
management of waste (TCEQ 2010b, p. 4). The TCEQ key operations 
include, but are not limited to, issuing, administering, renewing, and 
modifying permits, water rights, licenses, or certifications for 
organizations and individuals whose activities have some potential or 
actual environmental impact that must be formally authorized by the 
agency; monitoring the current condition of a geographic area or 
natural resource, often through sampling or surveys; and identifying, 
verifying, and tracking violations of regulations and initiating 
enforcement actions in response to violations (TCEQ 2010b, p. 21). The 
TCEQ developed the Clean Rivers Program to implement the goals of the 
Texas Clean Rivers Act (TCRA), described below.
    The TCRA, which was passed in 1991 by the Texas legislature, 
requires that basinwide water quality assessments be conducted for each 
river basin in Texas (Nueces River Authority 2010, p. 1). The goal of 
the TCRA is to provide waterways in the State with coordinated 
monitoring and protection, to identify the locations of water quality 
problems, and develop solutions on a river basin by river basin basis. 
The Clean Rivers Program is a partnership involving the TCEQ, other 
State agencies, river authorities, local governments, industry, and 
citizens (Nueces River Authority 2010, p. 1). Also, the Nueces River 
Authority was created in 1935 by special act of the 44th Texas 
Legislature codified as Article 8280-115 (Texas Water Code Auxiliary 
Laws, as amended). Under supervision of the TCEQ, the Nueces River 
Authority has broad authority to preserve, protect, and develop surface 
water resources, including flood control, irrigation, navigation, water 
supply, wastewater treatment, and water quality control. The Nueces 
River Authority serves all or parts of 22 counties in Texas, covering 
over 17,000 square miles (44,030 square kilometers), including the 
drainage area of the Nueces River and its tributaries and the adjoining 
coastal basins.
    Under the Clean Rivers Program and using a watershed management 
approach, the Nueces River Authority and TCEQ work together to identify 
and evaluate surface water quality issues and to establish priorities 
for corrective action within the Nueces River basin (Nueces River 
Authority 2010, p. 1). The Nueces River Authority and TCEQ conduct 
quarterly water quality monitoring at routine monitoring sites, testing 
for such things as wastewater discharge, runoff from quarry operations, 
accidental spills, ammonia excreted by animals or from fertilizers, and 
agricultural runoff, among many other things (Nueces River Authority 
2010, pp. 2-3). If water quality issues are detected, the Nueces River 
Authority and TCEQ may take appropriate corrective actions.
    Lastly, the TPWD recognized the upper reaches of the West Nueces, 
Nueces, Frio, and Sabinal Rivers as ecologically significant river and 
stream

[[Page 48784]]

segments (Norris et al. 2005, p. 3). Designation of a stream segment as 
ecologically unique offers a certain degree of protection from 
activities such as reservoir construction (Norris et al. 2005, p. 5). 
This designation does not impart protection from degradation, but 
rather prohibits a State agency or political subdivision of the State 
from financing the actual construction of a reservoir in a specific 
river or stream segment designated as ecologically significant by the 
legislature under section 16.051(f) of the Texas Water Code (Norris et 
al. 2005, p. 4).
Summary of Factor D
    In conclusion, there are Federal and State regulatory protections 
currently in place offering some levels of protection for the Nueces 
River shiner from such factors as degraded water quality, pollution, 
and reservoir construction. However, as discussed in other Factors of 
the Nueces River shiner, we have not identified any threats to the 
species that are likely to negatively affect the status of the species 
such that an inadequacy of existing regulatory mechanisms is likely to 
be a threat to the species. Therefore, we find that the Nueces River 
shiner is not in danger of extinction now or in the foreseeable future 
as a result of inadequacy of existing regulatory mechanisms.

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

    Global climate change, and associated effects on regional climatic 
regimes, is not well understood, but model predictions are that 
temperatures in the southwestern United States will continue to 
increase, with extreme weather events (such as heat waves, drought, and 
flooding) occurring with more frequency (Archer and Predick 2008, p. 
24). Also, there is some scientific information suggesting that fish in 
streams in southwestern North America may be vulnerable to extirpation 
or extinction due to global climate change because many fish species 
are already living near their lethal thermal limits (Mathews and 
Zimmerman 1990, p. 26). Endemic species, like the Nueces River shiner, 
which only inhabits the spring-fed headwaters of the Nueces River, 
could be more vulnerable to rising stream temperatures because they may 
not be able to move to more suitable areas. On the other hand, spring-
fed streams have nearly constant environmental conditions, such as 
temperature, due to the constancy of groundwater chemistry and 
discharge (Hoagstrom et al. 2011, p. 22). Thus, areas with substantial 
connections to aquifers may sustain endemic fishes because groundwater 
responds slowly to climate change, buffering against fluctuations in 
climate conditions (Hoagstrom et al. 2011, p. 22). Additionally, we are 
not aware of any research that has been conducted on water temperature 
tolerance of the Nueces River shiner. Because the Nueces River shiner's 
water temperature tolerance is unknown, the point at which rising 
stream temperatures may impact the species is also unknown.
    Likewise, recent models on climate change have indicated that 
annual mean precipitation in the southwestern United States is likely 
to decrease (Intergovernmental Panel on Climate Change (IPCC) 2007, p. 
887). Decreased precipitation could result in diminished water flows, 
which may cause losses in habitat diversity, reduce stream 
productivity, and degrade water quality (Norris et al. 2005, p. 1). 
While it appears reasonable to assume that climate change could affect 
the Nueces River shiner by reduced water flows, we lack sufficient 
certainty to know specifically how climate change will affect the 
species. We have not identified, nor are we aware of, any data on an 
appropriate scale to evaluate habitat or population trends for the 
Nueces River shiner within its range, or to make predictions on future 
trends and whether the species will actually be impacted.
    There are multiple hypothetical outcomes associated with climate 
change that could potentially affect the Nueces River shiner, but we 
lack predictive local or regional models on how climate change will 
specifically affect the Nueces River shiner or its habitat. Currently, 
we have no certainty regarding the timing, magnitude, or effects of 
impacts. Therefore, we find at this time that it is not possible to 
make reliable predictions of climate change effects on the status of 
the Nueces River shiner due to current limitations in available data 
and climate models. Based on the best available information and our 
current knowledge and understanding, we find that the Nueces River 
shiner is not in danger of extinction now or in the foreseeable future 
as a result of natural or other manmade threats affecting its continued 
existence.

Finding for the Nueces River Shiner

    As required by the Act, we considered the five factors in assessing 
whether the Nueces River shiner is threatened or endangered throughout 
all or a significant portion of its range. We examined the best 
scientific and commercial information available regarding the past, 
present, and future threats faced by the species. We reviewed the 
petition, information available in our files, other available published 
and unpublished information, and we consulted with recognized species 
experts and State agencies.
    In considering what factors might constitute threats, we must look 
beyond the mere exposure of the species to the factor to determine 
whether the species responds to the factor in a way that causes actual 
impacts to the species. If there is exposure to a factor, but no 
response, or only a positive response, that factor is not a threat. If 
there is exposure and the species responds negatively, the factor may 
be a threat and we then attempt to determine how significant a threat 
it is. If the threat is significant, it may drive or contribute to the 
risk of extinction of the species such that the species warrants 
listing as threatened or endangered as those terms are defined by the 
Act. This does not necessarily require empirical proof of a threat. The 
combination of exposure and some corroborating evidence of how the 
species is likely impacted could suffice. The mere identification of 
factors that could impact a species negatively is not sufficient to 
compel a finding that listing is appropriate; we require evidence that 
these factors are operative threats that act on the species to the 
point that the species meets the definition of threatened or endangered 
under the Act.
    Our review of all the available information does not support a 
determination that any current activities or activities in the 
foreseeable future threaten the Nueces River shiner or its habitat to 
the point that the species meets the definition of threatened or 
endangered under the Act. There is no evidence indicating that reduced 
water flow, improper grazing of livestock, pollution, and land use are 
affecting the species or its habitat. Overutilization, disease, and 
predation are not known concerns for this species. We find that no 
existing regulatory mechanisms are inadequate to limit or prevent 
possible negative impacts from human activities. Climate change could 
affect the habitat of the Nueces River shiner in the future, but we 
have no certainty regarding the timing, magnitude, or effects of 
impacts to the species.
    Based on our review of the best available scientific and commercial 
information pertaining to the five factors, we find that there are no 
threats to indicate that the Nueces River shiner is in danger of 
extinction (endangered) or likely to become endangered within the 
foreseeable future (threatened)

[[Page 48785]]

throughout its range. Therefore, we find that listing the Nueces River 
shiner as endangered or threatened is not warranted throughout its 
range at this time.

Summary of Information Pertaining to the Five Factors for Plateau 
Shiner

    The plateau shiner's range is in close proximity to the Nueces 
River shiner's range. Subsequently, many of the factors that may affect 
the Nueces River shiner also may affect the plateau shiner. Therefore, 
much of the information presented in this section is similar to that 
presented above for the Nueces River shiner. However, the plateau 
shiner does inhabit separate headwaters of the Sabinal and Frio Rivers 
in the Edwards Plateau region of Texas, whereas the Nueces River shiner 
inhabits the headwaters of the Nueces River. The Sabinal and Frio 
Rivers are part of the Nueces River basin because they flow into and 
become part of the Nueces River in south-central Texas. Because the 
plateau shiner occupies separate headwaters than the Nueces River 
shiner, we will discuss any potential threats that might uniquely 
affect the plateau shiner, but because these two shiner species occupy 
nearby headwaters and are very similar species, we will refer to the 
information above, where appropriate.

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

    The following factors have the potential to affect the habitat or 
range of the plateau shiner: Livestock grazing, reduced water quantity, 
impaired water quality, and land use. Below, we discuss each of these 
factors and determine whether or not they constitute a threat to the 
plateau shiner.
Livestock Grazing
    While we know that livestock grazing occurs within the range of the 
species, we could find no information on the extent or intensity of 
historical, current, or future livestock grazing practices or impacts 
that grazing may be having on the species. As previously mentioned, 
Richardson and Gold (1995, p. 35) cited a personal communication in 
their study to conclude that much of the land in the Nueces River basin 
was used for agriculture, and that overgrazing by cattle posed serious 
problems for aquatic fauna. However, based on the best available 
information, we could find no evidence or data to indicate that 
improper livestock grazing affects the plateau shiner or its habitat. 
Therefore, we find that the plateau shiner is not in danger of 
extinction now or in the foreseeable future as a result of livestock 
grazing.
Water Quantity
    Please see Factor A discussion of the Nueces River shiner for a 
more thorough discussion of the potential impacts of reduced water flow 
on these fish. As stated above and based on the best available 
information, we have no evidence to indicate that reduced stream flow 
is occurring within the range of the plateau shiner at a level that may 
be impacting the species. As we have noted previously, Edwards et al. 
(2008, p. 25) analyzed stream flow measurements in the Frio, Sabinal, 
and Nueces Rivers for the last decade and showed that there was a 
normal range of flow variation in each of the streams. Therefore, based 
on the best available information, we find that the plateau shiner is 
not in danger of extinction now or in the foreseeable future as a 
result of reduced water flows.
Water Quality
    Based on the best available information, there is no evidence that 
diminished water quality caused by pollution may be occurring within 
the range of the plateau shiner at a level that affects the species or 
its habitat. In 2005, the TPWD noted the Frio and Sabinal Rivers as 
having high water quality and exceptional aquatic life (Norris et al. 
2005, pp. 16, 19). However, water quality tests have been conducted on 
other areas where plateau shiners are known to occur, such as the 
uppermost reaches of the Sabinal River, and water quality impairment 
has been detected (Nueces River Authority 2010, p. 16). Even though a 
stream segment in the upper Frio River remains on the State of Texas' 
Clean Water Act 303(d) list as impaired and is within the range of the 
species, there does not appear to be adverse impacts to the plateau 
shiner or its habitat.
    In 2000, a 47-mi (76-km) stream segment from where the West Frio 
River and the East Frio River flow together in Real County, at a point 
110 yards (yd) (100 meters (m)) upstream of Highway 90 in Uvalde 
County, was included on the State of Texas' Clean Water Act 303(d) list 
as impaired due to concentrations of dissolved oxygen below criteria 
associated with exceptional aquatic life (Bonner et al. 2004, pp. 1-3). 
The dissolved oxygen criteria was established based on the fact that 
organisms that live in water need oxygen to live, and in waters with 
depressed dissolved oxygen levels, organisms may not have sufficient 
oxygen to survive (Nueces River Authority 2010, p. 3). Following this 
designation as impaired in 2000, TCEQ initiated a project to verify the 
impairment through the collection of additional physical, chemical, and 
biological data (Bonner et al. 2004, p. 3). As a result, Bonner et al. 
(2004, p. 1) conducted a 3-year monitoring study of water quality at 
several stations along the upper Frio River from 2002 through 2004. 
Based upon the 24-hour dissolved oxygen data collected for this study, 
Bonner et al. (2004, p. 20) found no impairment due to depressed levels 
of dissolved oxygen in the water and concluded that the upper Frio 
River was meeting the exceptional aquatic life use standard. Routine 
water samples yielded no significant levels of nutrient impairment 
(Bonner et al. 2004, p. 20). Therefore, Bonner et al. (2004, p. 1) 
recommended removing the upper Frio River from the State's list of 
impaired waters.
    As part of the impairment verification monitoring project on this 
47-mi (76-km) stream segment in the upper Frio River, Ecological 
Communications Corporation conducted biological data collection and 
analysis in September 2002, August 2003, and October 2003 (Walther and 
Palma 2004, p. 3). Based on the biological and habitat data collected 
by Ecological Communications Corporation, it appeared that the number 
and diversity of aquatic organisms were lower than the established 
standards set forth in the Texas Clean Water Act (Walther and Palma 
2004, p. 8).
    In 2008 and 2010, this same stream segment of the Frio River 
continued to remain on the 303(d) list because of concerns for impaired 
habitat, fish community, and organisms living at the bottom of the 
water (Nueces River Authority 2008, pp. 56-58; Nueces River Authority 
2010, p. 17; TCEQ 2010a, p. 86). However, all testing resulted in data 
that were within TCEQ's normal range, which included dissolved oxygen, 
pH, total phosphorus, nitrates, ammonia, chlorophyll-a, nutrients, and 
bacteria (Nueces River Authority 2008, pp. 56-58; Nueces River 
Authority 2010, p. 17). Also, no hypotheses were given for the reasons 
this stream segment had aquatic life uses that were lower than 
established standards (Nueces River Authority 2008, 2010). Edwards et 
al. (2008, p. 29) analyzed the biological integrity of streams in the 
upper headwaters of the Nueces River basin, and noted that the water 
quality was generally high and the fish fauna present were typical of 
high-quality spring-fed streams. Also, Edwards et al. (2008, p. 6) 
stated that the plateau shiner was one of the most abundant fishes 
surveyed.

[[Page 48786]]

    Another stretch of the Frio River, a segment 158 mi (254 km) long, 
from 110 yds (100 m) upstream of Highway 90 in Uvalde County to the 
confluence with Choke Canyon Reservoir in McMullen County, was placed 
on the 303(d) list as impaired for bacteria in 2008 and 2010 (Nueces 
River Authority 2008, pp. 66-71; Nueces River Authority 2010, p. 20; 
TCEQ 2010a, p. 86). However, this stretch of the Frio River is further 
downstream in south-central Texas, outside of the plateau shiner's 
range. Therefore, factors affecting this stream segment are not likely 
to affect the plateau shiner or its habitat.
    As previously noted above under Factor A analysis for the Nueces 
River shiner, Edwards et al. (2008, p. 3) conducted a study to find out 
if there were potential impacts that may be factors in population and 
range declines among native fishes, including the plateau shiner, in 
the upper headwaters of the Nueces River basin. Edwards et al. (2008, 
p. 27) analyzed the biological integrity of streams in the upper Nueces 
River basin, including the Sabinal and Frio Rivers where the plateau 
shiner is found. Edwards et al. (2008, p. 27) found that the Sabinal 
and Frio Rivers had exceptional water quality within the range of the 
plateau shiners. Also, Edwards et al. (2008, p. 29) noted that the 
water quality was generally high and the fish fauna present were 
typical of high-quality spring-fed streams within the southern Edwards 
Plateau. On the other hand, Edwards et al. (2008, p. 29) noted a number 
of significant impacts, such as development along the watercourse, low-
head dams along the Sabinal River, and at times intense recreational 
pressures during the summer months, especially along the Frio River. 
Even with these impacts to the streams, the headwaters of the Sabinal 
and Frio Rivers maintained much of their integrity as evidenced by the 
numerous indicator fishes (fishes thought to be sensitive to, and serve 
as an early warning indicator of, environmental changes), such as the 
plateau shiner (Edwards et al. 2008, p. 27). In fact, Edwards et al. 
(2008, p. 6) stated that the plateau shiner was one of the most 
abundant fishes. Because the plateau shiner was one of the most 
abundant species surveyed, it does not appear that factors related to 
development along the watercourse, low-head dams, and recreational use 
are negatively impacting the plateau shiner.
    In conclusion, even though a portion of the Frio River is listed as 
impaired by the State of Texas under the Clean Water Act 303(d) because 
of concerns for impaired habitat, fish community, and organisms living 
at the bottom of the water, a study conducted by Edwards et al. (2008) 
found no evidence of actual impacts on the plateau shiner. Likewise, 
Bonner et al. (2004, p. 20) previously found no impairment due to 
depressed levels of dissolved oxygen in the water and concluded that 
the upper Frio River was meeting the exceptional aquatic life use 
standard. In addition, all water quality monitoring in the impaired 
stream segment resulted in water parameters within the normal range 
(Nueces River Authority 2008, pp. 56-58; Nueces River Authority 2010, 
p. 17). Based on the best available information, we find that the 
plateau shiner is not in danger of extinction now or in the foreseeable 
future as a result of degraded water quality.
Land Use
    The primary land use factors that could affect the plateau shiner 
are recreation, agricultural activities, and land development. The 
upper Frio River is used extensively for recreation, and the extensive 
recreational usage is expected to continue in the future (Walther and 
Palma 2004, p. 1; Nueces River Authority 1998, p. 2). Although we could 
find no evidence to indicate that recreational usage may be impacting 
plateau shiner in the Sabinal River, it is reasonable to assume that 
recreational use does occur in this river. The Frio River is very 
popular for recreational activities such as canoeing, tubing, fishing, 
and wildlife viewing (Norris et al. 2005, p. 15). A study was conducted 
on the upper Frio River to evaluate the impact of recreational use and 
land development on water quality and the aquatic biological community 
(Nueces River Authority 1998, p. 2). Impacts were evaluated through the 
collection and interpretation of information on land uses and historic 
utilization, and by conducting biological assessments, toxicity 
testing, and water quality analysis (Nueces River Authority, p. 2). The 
Nueces River Authority (1998, p. 3) noted that the upper Frio River was 
primarily forest and rangeland with some agricultural activities, 
mainly orchards and nurseries, and very limited urban land development, 
primarily related to tourist and camping accommodations. Overall, the 
chemical and physical water quality of the upper Frio River was found 
to be very good, and recreational use had little impact on river 
quality during the spring and summer visitation period (Nueces River 
Authority 1998, p. 10). This is further supported by an Edwards et al. 
(2008, p. 27) study, which found that the Sabinal and Frio Rivers had 
exceptional water quality. Based on our review of the best available 
information, we find that the plateau shiner is not in danger of 
extinction now or in the foreseeable future as a result of recreational 
use or any other type of land use.
Summary of Factor A
    We relied on the best available scientific and commercial 
information, which does not indicate that any of the factors discussed 
above are impacting the plateau shiner at a level that constitutes a 
threat to the species. Therefore, we find that the plateau shiner is 
not in danger of extinction now or in the foreseeable future as a 
result of the present or foreseeable destruction, modification, or 
curtailment of its habitat or range.

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

    Based on the best available scientific and commercial information, 
there is no evidence that impacts are occurring to the plateau shiner 
or its habitat under this factor. Other than the scientific studies 
referenced in this finding, the plateau shiner is not used for any 
commercial, recreational, or educational purposes. Therefore, we find 
that the plateau shiner is not in danger of extinction now or in the 
foreseeable future as a result of overutilization for commercial, 
recreational, scientific, or educational purposes.

Factor C. Disease or Predation

    As with the Nueces River shiner, we are not aware of any research 
that has been conducted to specifically examine disease or predation in 
the plateau shiner. There was no mention of disease or predation in our 
review of the best available information. Also, we are not aware of any 
nonnative species that may prey on the plateau shiner. Therefore, we 
find that the plateau shiner is not in danger of extinction now or in 
the foreseeable future as a result of disease or predation.

Factor D. The Inadequacy of Existing Regulatory Mechanisms

    As we discussed in more detail above under Factor D analysis for 
the Nueces River shiner, there are Federal and State regulatory 
protections currently in place offering some levels of protection for 
the plateau shiner, particularly from such factors as degraded water 
quality, pollution, and reservoir construction. The Factor D analysis 
for the Nueces River shiner presented above also pertains to the 
plateau shiner's habitat and range. However, as discussed in other 
Factors for the plateau shiner, we have not identified any threats to 
the

[[Page 48787]]

species that are negatively affecting the status of the species, such 
that an inadequacy of regulatory mechanisms is likely to be a threat to 
the species. Therefore, we find that the plateau shiner is not in 
danger of extinction now or in the foreseeable future as a result of 
inadequacy of regulatory mechanisms.

Factor E. Other Natural or Manmade Factors Affecting Its Continued 
Existence

    The same impacts discussed above under the Factor E analysis for 
the Nueces River shiner also apply to the plateau shiner. As with the 
Nueces River shiner, there are multiple hypothetical outcomes 
associated with climate change that could potentially affect the 
plateau shiner, but we lack predictive local or regional models on how 
climate change will specifically affect the plateau shiner or its 
habitat. Currently, we have no certainty regarding the timing, 
magnitude, or effects of impacts from climate change. Therefore, we 
conclude that at this time it is not possible to make reliable 
predictions of climate change effects on the status of the plateau 
shiner due to current limitations in available data and climate models. 
Based on the best available information, we find that the plateau 
shiner is not in danger of extinction now or in the foreseeable future 
as a result other natural or manmade factors affecting its continued 
existence.

Finding for the Plateau Shiner

    As required by the Act, we considered the five factors in assessing 
whether the plateau shiner is threatened or endangered throughout all 
or a significant portion of its range. We examined the best scientific 
and commercial informa