[Federal Register Volume 88, Number 161 (Tuesday, August 22, 2023)]
[Proposed Rules]
[Pages 57046-57060]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-17667]



[[Page 57046]]

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R2-ES-2023-0069; FF09E21000 FXES1111090FEDR 234]
RIN 1018-BE77


Endangered and Threatened Wildlife and Plants; Endangered Species 
Status for Toothless Blindcat and Widemouth Blindcat

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Proposed rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), propose to 
list the toothless blindcat (Trogloglanis pattersoni) and widemouth 
blindcat (Satan eurystomus), two cavefish species from the Edwards 
Aquifer in Bexar County, Texas, as endangered species under the 
Endangered Species Act of 1973, as amended (Act). This determination 
also serves as our 12-month finding on a petition to list the toothless 
blindcat and widemouth blindcat. After a review of the best available 
scientific and commercial information, we find that listing both 
species is warranted. If we finalize this rule as proposed, it would 
extend the Act's protections to these species. We have determined that 
designation of critical habitat is not prudent.

DATES: We will accept comments received or postmarked on or before 
October 23, 2023. Comments submitted electronically using the Federal 
eRulemaking Portal (see ADDRESSES, below) must be received by 11:59 
p.m. eastern time on the closing date. We must receive requests for a 
public hearing, in writing, at the address shown in FOR FURTHER 
INFORMATION CONTACT by October 6, 2023.

ADDRESSES: You may submit comments by one of the following methods:
    (1) Electronically: Go to the Federal eRulemaking Portal: https://www.regulations.gov. In the Search box, enter FWS-R2-ES-2023-0069, 
which is the docket number for this rulemaking. Then, click on the 
Search button. On the resulting page, in the panel on the left side of 
the screen, under the Document Type heading, check the Proposed Rule 
box to locate this document. You may submit a comment by clicking on 
``Comment.''
    (2) By hard copy: Submit by U.S. mail to: Public Comments 
Processing, Attn: FWS-R2-ES-2023-0069, U.S. Fish and Wildlife Service, 
MS: PRB/3W, 5275 Leesburg Pike, Falls Church, VA 22041-3803.
    We request that you send comments only by the methods described 
above. We will post all comments on https://www.regulations.gov. This 
generally means that we will post any personal information you provide 
us (see Information Requested, below, for more information).
    Availability of supporting materials: Supporting materials, such as 
the species status assessment report, are available at https://www.regulations.gov at Docket No. FWS-R2-ES-2023-0069.

FOR FURTHER INFORMATION CONTACT: Karen Myers, Field Supervisor, U.S. 
Fish and Wildlife Service, Austin Ecological Services Field Office, 
1505 Ferguson Lane, Austin, TX 78754; telephone 512-937-7371. 
Individuals in the United States who are deaf, deafblind, hard of 
hearing, or have a speech disability may dial 711 (TTY, TDD, or 
TeleBraille) to access telecommunications relay services. Individuals 
outside the United States should use the relay services offered within 
their country to make international calls to the point-of-contact in 
the United States.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. Under the Act, a species warrants 
listing if it meets the definition of an endangered species (in danger 
of extinction throughout all or a significant portion of its range) or 
a threatened species (likely to become an endangered species within the 
foreseeable future throughout all or a significant portion of its 
range). If we determine that a species warrants listing, we must list 
the species promptly and designate the species' critical habitat to the 
maximum extent prudent and determinable. We have determined that the 
toothless blindcat and widemouth blindcat both meet the definition of 
an endangered species; therefore, we are proposing to list both as 
such. Listing a species as an endangered or threatened species can be 
completed only by issuing a rule through the Administrative Procedure 
Act rulemaking process (5 U.S.C. 551 et seq.).
    What this document does. We propose to list the toothless blindcat 
and the widemouth blindcat as endangered species under the Act.
    The basis for our action. Under the Act, we may determine that a 
species is an endangered or threatened species because of any of five 
factors: (A) The present or threatened destruction, modification, or 
curtailment of its habitat or range; (B) overutilization for 
commercial, recreational, scientific, or educational purposes; (C) 
disease or predation; (D) the inadequacy of existing regulatory 
mechanisms; or (E) other natural or manmade factors affecting its 
continued existence. We have determined that the toothless blindcat and 
widemouth blindcat are endangered due to the threat of mortality from 
groundwater well pumping (Factor E).
    The toothless blindcat and the widemouth blindcat occupy a limited 
range, and populations of both species have likely been severely 
reduced since the introduction of groundwater wells in the late 19th to 
early 20th centuries. The lethal discharge of the species through 
groundwater wells could potentially impact the populations directly, 
with an estimated cumulative loss of thousands of individuals. 
Additionally, the assumed life history traits (such as increased age at 
first reproduction, lower numbers of reproductively active females, 
reduced numbers of eggs, slower growth rates, and longer life spans) of 
both species make them more susceptible to long-term impacts on 
demographic structure in the form of lower numbers of sexually mature 
fish, reduced reproductive output, and diminished recruitment of 
younger individuals.
    Section 4(a)(3) of the Act requires the Secretary of the Interior 
(Secretary), to the maximum extent prudent and determinable, to 
designate critical habitat concurrent with listing. We have determined 
that designating critical habitat for the toothless blindcat and 
widemouth blindcat is not prudent because the main driver of both 
species' status is direct mortality resulting from groundwater well 
pumping (Factor E). The wells constructed in blindcat habitat are not 
affecting the species through habitat destruction or modification; 
instead, it is the capture, entrainment, and death of individuals due 
to uptake from groundwater well pumping that threatens the species. 
Since we have determined that the present or threatened destruction, 
modification, or curtailment of both species' habitats or range is not 
a threat to the toothless blindcat or the widemouth blindcat, we 
determine that designation of critical habitat is not prudent for the 
species.

Information Requested

    We intend that any final action resulting from this proposed rule 
will be based on the best scientific and commercial data available and 
be as accurate and as effective as possible. Therefore, we request 
comments or

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information from other governmental agencies, Native American Tribes, 
the scientific community, industry, or any other interested parties 
concerning this proposed rule. We particularly seek comments 
concerning:
    (1) The species' biology, ranges, and population trends, including:
    (a) Biological or ecological requirements of the species, including 
habitat requirements for feeding, breeding, and sheltering;
    (b) Genetics and taxonomy;
    (c) Historical and current ranges, including distribution patterns 
and the locations of any additional populations of these species;
    (d) Historical and current population levels, and current and 
projected trends; and
    (e) Past and ongoing conservation measures for these species, their 
habitats, or both.
    (2) Threats and conservation actions affecting these species, 
including:
    (a) Factors that may be affecting the continued existence of the 
species, which may include habitat modification or destruction, 
overutilization, disease, predation, the inadequacy of existing 
regulatory mechanisms, or other natural or manmade factors.
    (b) Biological, commercial trade, or other relevant data concerning 
any threats (or lack thereof) to these species.
    (c) Existing regulations or conservation actions that may be 
addressing threats to these species.
    (3) Additional information concerning the historical and current 
status of these species.
    (4) Information regarding our determination that designating 
critical habitat for the toothless blindcat and widemouth blindcat is 
not prudent.
    Please include sufficient information with your submission (such as 
scientific journal articles or other publications) to allow us to 
verify any scientific or commercial information you include.
    Please note that submissions merely stating support for, or 
opposition to, the action under consideration without providing 
supporting information, although noted, do not provide substantial 
information necessary to support a determination. Section 4(b)(1)(A) of 
the Act directs that determinations as to whether any species is an 
endangered or a threatened species must be made solely on the basis of 
the best scientific and commercial data available, and section 4(b)(2) 
of the Act directs that the Secretary shall designate critical habitat 
on the basis of the best scientific data available.
    You may submit your comments and materials concerning this proposed 
rule by one of the methods listed in ADDRESSES. We request that you 
send comments only by the methods described in ADDRESSES.
    If you submit information via https://www.regulations.gov, your 
entire submission--including any personal identifying information--will 
be posted on the website. If your submission is made via a hardcopy 
that includes personal identifying information, 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. We 
will post all hardcopy submissions on https://www.regulations.gov.
    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.
    Our final determinations may differ from this proposal because we 
will consider all comments we receive during the comment period as well 
as any information that may become available after this proposal. Based 
on the new information we receive (and, if relevant, any comments on 
that new information), we may conclude that one or both of these 
species is threatened instead of endangered, or we may conclude that 
one or both of these species does not warrant listing as either an 
endangered species or a threatened species. In our final rule, we will 
clearly explain our rationale and the basis for our final decisions, 
including why we made changes, if any, that differ from this proposal.

Public Hearing

    Section 4(b)(5) of the Act provides for a public hearing on this 
proposal, if requested. Requests must be received by the date specified 
in DATES. Such requests must be sent to the address shown in FOR 
FURTHER INFORMATION CONTACT. We will schedule a public hearing on this 
proposal, if requested, and announce the date, time, and place of the 
hearing, as well as how to obtain reasonable accommodations, in the 
Federal Register and local newspapers at least 15 days before the 
hearing. We may hold the public hearing in person or virtually via 
webinar. We will announce any public hearing on our website, in 
addition to the Federal Register. The use of virtual public hearings is 
consistent with our regulations at 50 CFR 424.16(c)(3).

Previous Federal Actions

    We identified the toothless blindcat and widemouth blindcat as 
category 2 candidates in our December 30, 1982, candidate notice of 
review (CNOR) (47 FR 58454). Category 2 candidates were defined as taxa 
for which we had information indicating that proposing to list the 
species was possibly appropriate, but for which substantial data were 
not available to biologically support a proposed rule. Both species 
remained so designated in subsequent CNORs (50 FR 37958, September 18, 
1985; 54 FR 554, January 6, 1989; 56 FR 58804, November 21, 1991; 59 FR 
58982, November 15, 1994). In our February 28, 1996, CNOR (61 FR 7596), 
we discontinued the designation of category 2 species as candidates; 
therefore, the toothless blindcat and widemouth blindcat were no longer 
candidate species.
    In August 1995, we received a petition from the American Society of 
Ichthyologists and Herpetologists (ASIH) and the Desert Fishes Council. 
The petition was to list three species, including the toothless 
blindcat and widemouth blindcat (ASIH 1995, entire). Subsequently, in 
1998, we published a 90-day finding that the petition did not present 
substantial information indicating that these species warranted listing 
(63 FR 48166; September 9, 1998).
    On June 25, 2007, we received a petition dated June 18, 2007, from 
Forest Guardians (now WildEarth Guardians) to list 475 species, 
including the toothless blindcat and widemouth blindcat, in the 
southwestern United States as endangered or threatened species and to 
designate critical habitat under the Act (Forest Guardians 2007, 
entire). On December 16, 2009, we published a partial 90-day finding 
(74 FR 66866) on 192 species from that petition; in that document, we 
announced that the petition presented substantial information that 
listing the toothless blindcat and widemouth blindcat may be warranted.

Peer Review

    A species status assessment (SSA) team prepared an SSA report for 
the toothless blindcat and widemouth blindcat. The SSA team was 
composed of Service biologists, in consultation with other species 
experts. The SSA report represents a compilation of the best scientific 
and commercial data available concerning the status of the species, 
including the impacts of past, present, and future factors (both 
negative and beneficial) affecting the species.
    In accordance with our joint policy on peer review published in the 
Federal Register on July 1, 1994 (59 FR 34270), and our August 22, 
2016, memorandum updating and clarifying the role of peer review of 
listing actions under the Act,

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we solicited independent scientific review of the information contained 
in the toothless blindcat and widemouth blindcat SSA report (Service 
2022, entire). We sent the SSA report to six independent peer reviewers 
and received four responses. Results of this structured peer review 
process can be found at https://www.regulations.gov under Docket No. 
FWS-R2-ES-2023-0069. In preparing this proposed rule, we incorporated 
the results of these reviews, as appropriate, into the SSA report, 
which is the foundation for this proposed rule.

Summary of Peer Reviewer Comments

    As discussed in Peer Review, above, we received comments from four 
peer reviewers on the draft SSA report. We reviewed all comments we 
received from the peer reviewers for substantive issues and new 
information regarding the content of the SSA report. The peer reviewers 
generally concurred with our methods and conclusions, and provided 
additional information, clarifications, and suggestions to improve the 
SSA. One peer reviewer questioned assumptions related to groundwater 
well mortality and habitat connectivity. Our review of the best 
available information regarding the impact of anthropogenic mortality 
(such as well mortality) on fish species similar to the toothless and 
widemouth blindcats (that is, fish species that are subterranean, are 
long-lived, and have reduced reproductive capacity) supports the 
findings of the SSA.

I. Proposed Listing Determination

Background

    A thorough review of the taxonomy, life history, and ecology of the 
toothless blindcat (Trogloglanis pattersoni) and widemouth blindcat 
(Satan eurystomus) is presented in the SSA report (Service 2022, 
entire).
    The toothless blindcat and widemouth blindcat are cavefish endemic 
to the San Antonio segment of the Edwards Aquifer in Bexar County, 
Texas. They inhabit a deep, inaccessible subterranean region of the 
aquifer, with all known specimens of both species having been collected 
from groundwater wells at depths at or greater than 308 meters (m) 
(1,010 feet (ft)). The toothless blindcat and the widemouth blindcat 
are members of the catfish (Siluriformes) family Ictaluridae, and are 
the only members of their respective genera, Trogloglanis and Satan 
(Arce-H et al. 2017, pp. 406-407, 415).
    The toothless blindcat and widemouth blindcat occur in a very deep 
portion of the San Antonio segment of the Edwards Aquifer, where they 
can likely move through the groundwater flowing through a system of 
interconnected subterranean conduits (Ford and Williams 2007, pp. 103-
106, 112-114; Culver and Pipan 2009, pp. 5-8; Veni 2012, pp. 603-608; 
White 2012, pp. 383-386). These caves and conduits are formed in the 
rock layers of the Edwards Aquifer through dissolution by groundwater 
(Livingston et al. 1936, pp. 72-73; Petitt and George 1956, p. 16; 
Maclay and Small 1986, p. 61).
    Due to their deep subterranean habitat, the toothless blindcat and 
widemouth blindcat exhibit several stygomorphic (adaptations to 
subterranean conditions) characteristics, including depigmentation, 
absence of fully developed eyes, and short lateral line canals 
(Lundberg 1982, pp. 77-78; Langecker and Longley 1993, pp. 978-980; 
Lundberg et al. 2017, pp. 163-164). Blindcats lack scales and possess 
eight barbels (whisker-like sensory organs) arranged around the snout 
and mouth (Eigenmann 1919, p. 398; Hubbs and Bailey 1947, pp. 5, 10; 
Lundberg 1982, p. 16; Burr et al. 2020, p. 42). The toothless blindcat 
and widemouth blindcat appear to be among the smallest known catfishes, 
reaching total lengths of up to 103.8 millimeters (mm) (4.1 inches 
(in)) and 136.9 mm (5.4 in), respectively (Hubbs and Bailey 1947, pp. 
8-10, 12-14; Suttkus 1961, pp. 62-63; Lundberg 1982, pp. 10-11; 
Langecker and Longley 1993, p. 977; Burr et al. 2020, p. 26).
    The toothless blindcat lacks teeth, and its jaw is thin and papery 
with a funnel-like mouth positioned ventrally below the snout (Hubbs 
and Bailey 1947, pp. 5, 11-12; Lundberg 1982, pp. 15-16). The widemouth 
blindcat possesses well-developed teeth, a robust jaw, and a larger 
mouth positioned transversely at the depressed and flat snout (Hubbs 
and Bailey 1947, p. 5). From their jaw and mouth morphology, as well as 
specimen stomach contents, we infer that the toothless blindcat is a 
detrivore that feeds on biofilm and other organic material, whereas the 
widemouth blindcat is likely an opportunistic predator capable of 
taking sizeable prey (Longley and Karnei 1978a, pp. 31, 34; Lundberg et 
al. 2017, pp. 160, 162).
    There is documentation of toothless blindcat individuals being 
expelled from eight wells and widemouth blindcat individuals from five 
wells, with overlapping expulsions at two wells (Zara Environmental 
2020, pp. 11-12; Diaz 2021, p. 30). Wells that have produced the 
species are relatively close, with an average distance between wells of 
4.5 kilometers (km) (2.8 miles (mi)) for the toothless blindcat and 6.3 
km (4.0 mi) for the widemouth blindcat (Service 2022, p. 45). Given the 
potential for hydrogeological connectivity, the species likely exist as 
single sympatric subterranean populations. Well depth ranges from 308 m 
(1,010 ft) to 582 m (1,909 ft) (Zara Environmental 2020, pp. 14-23), 
making these species some of the deepest known cavefish (Trajano 2001, 
p. 140; Fi[scaron]er et al. 2014, p. 976). These wells are distributed 
along a southwest to northeast trending line through Bexar County, 
roughly paralleling the southeastern boundary of the aquifer's artesian 
zone. The artesian zone of the Edwards Aquifer is where hydraulic 
pressure of groundwater forces water to the surface, where the water 
escapes through springs, seeps, or wells drilled into the aquifer 
(Lindgren et al. 2004, pp. 35, 39-40).
    The southeastern extent of the artesian zone represents the limit 
of freshwater in the Edwards Aquifer (Hovorka et al. 1995, p. 3; Sharp 
and Smith 2019, pp. 151-152). Groundwater from the aquifer's artesian 
zone is considered high-quality with low dissolved solids ranging from 
300 to 500 milligrams/liter (mg/l) (Petitt and George 1956, p. 76; 
Maclay et al. 1980, p. 8). To the southeast of the artesian zone, 
dissolved solids increase and the groundwater becomes progressively 
more saline (Groschen 1993, pp. 2, 7; Groschen and Buszka 1997, pp. 1-
3). The contact point where freshwater (i.e., <1,000 mg/l dissolved 
solids) generally meets saline water (i.e., >1,000 mg/l) is termed the 
``freshwater/saline-water interface'' (Arnow 1959, p. 40; Maclay et al. 
1980, p. 10; Groschen 1993, p. 2; Groschen and Buszka 1997, pp. 1, 3). 
All wells where blindcats have been expelled occur just to the 
northwest of the freshwater/saline-water interface on the freshwater 
side.
    Neither blindcat species has ever been directly observed in its 
natural subterranean habitat, but we can infer the species' needs from 
their location and from the life-history of other cavefish species. 
Subterranean habitat for the toothless blindcat and widemouth blindcat 
appears to be centered in an area of greater aquifer permeability in 
Bexar County (Maclay 1995, pp. 26-27; Hovorka et al. 1996, pp. 50, 54-
57; Hovorka et al. 2004, p. 19). Concentrated groundwater flow in this 
area has likely resulted in the formation of enlarged faults, 
fractures, and cavernous openings that provide suitable physical 
habitat for the blindcats (Lindgren et al. 2004, pp. 16).
    The area along the freshwater/saline-water interface is likely an 
area of focused groundwater movement due to

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greater porosity and permeability in that area (Maclay and Small 1986, 
p. 66; Hovorka et al. 1996, pp. 50, 54-57; Worthington 2003, pp. 16, 
20, 23-24; Hovorka et al. 2004, pp. 19, 42; Lindgren et al. 2004, pp. 
11, 15, 17-21, 26). We infer the importance of this location for these 
species from the hydraulic connectivity and the existence of aquifer 
food resources at great depth near this interface (Birdwell and Engel 
2009, pp. 153-155; Engel and Randall 2011, pp. 313-314, 318; Hutchins 
et al. 2013, pp. 254-255; Bishop et al. 2014, pp. 90-91; Hutchins et 
al. 2016, pp. 1535-1539). Due to the historical absence of human-
related contamination, we also infer that the toothless blindcat and 
widemouth blindcat are adapted to and require groundwater of a certain 
quality from the Edwards Aquifer that is relatively free of 
anthropogenic contaminants.
    Longevity and reproduction of the toothless blindcat and widemouth 
blindcat is not known but can be inferred from other cavefish species. 
Cavefishes are generally characterized by life history traits such as 
increased age at first reproduction, lower numbers of reproductively 
active females, reduced numbers of eggs, slower growth rates, and 
longer life spans (Poulson 1963, pp. 266, 268, 275; Trajano 1997, p. 
367; Trajano 2001, pp. 152-153; Trajano and Bichuette 2007, p. 114; 
Niemiller and Poulson 2010, pp. 220-227, 232-235; Secutti and Trajano 
2021, p. 103). Estimated lifespans of other cavefish range from 8 to 45 
years (Niemiller and Poulson 2010, p. 226; Trajano 1997, p. 367; 
Trajano 2001, pp. 151-152; Trajano and Bichuette 2007, p. 114; Secutti 
and Trajano 2021, p. 103).
    Because the blindcats are cavefish, we assume that age at first 
reproduction for the toothless blindcat and widemouth blindcat is 
likely older than 2 years of age, and the age at reproductive maturity 
is likely 6 years of age or older; this is older than the age at first 
reproduction for surface catfish species and similar to or older than 
the age of reproductive maturity for the northern cavefish (Niemiller 
and Poulson 2010, p. 221). Also, like other cavefishes (Niemiller and 
Poulson 2010, pp. 221-222), we assume that only a fraction (3 percent 
to 13 percent) of female toothless blindcats and widemouth blindcats 
produce offspring on an annual basis. Clutch size is likely comparable 
to the small clutches produced by Noturus species (fewer than 200 
eggs). Adult toothless blindcats and widemouth blindcats probably reach 
significant ages for catfishes, with maximum ages of multiple decades 
(more than 25 years). The toothless blindcat and widemouth blindcat 
inhabit a subterranean system that is well-buffered from immediate 
seasonal changes. However, seasonality of reproduction cannot be 
dismissed, as these fish may respond to periods of high or low 
groundwater flow in relation to aquifer recharge.

Regulatory and Analytical Framework

Regulatory Framework

    Section 4 of the Act (16 U.S.C. 1533) and the implementing 
regulations in title 50 of the Code of Federal Regulations set forth 
the procedures for determining whether a species is an endangered 
species or a threatened species, issuing protective regulations for 
threatened species, and designating critical habitat for endangered and 
threatened species. In 2019, jointly with the National Marine Fisheries 
Service, the Service issued a final rule that revised the regulations 
in 50 CFR part 424 regarding how we add, remove, and reclassify 
endangered and threatened species and the criteria for designating 
listed species' critical habitat (84 FR 45020; August 27, 2019). On the 
same day, the Service also issued final regulations that, for species 
listed as threatened species after September 26, 2019, eliminated the 
Service's general protective regulations automatically applying to 
threatened species the prohibitions that section 9 of the Act applies 
to endangered species (84 FR 44753; August 27, 2019).
    The Act defines an ``endangered species'' as a species that is in 
danger of extinction throughout all or a significant portion of its 
range, and a ``threatened species'' as a species that is likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. The Act requires that we 
determine whether any species is an endangered species or a threatened 
species because of any of the following 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.
    These factors represent broad categories of natural or human-caused 
actions or conditions that could have an effect on a species' continued 
existence. In evaluating these actions and conditions, we look for 
those that may have a negative effect on individuals of the species, as 
well as other actions or conditions that may ameliorate any negative 
effects or may have positive effects.
    We use the term ``threat'' to refer in general to actions or 
conditions that are known to or are reasonably likely to negatively 
affect individuals of a species. The term ``threat'' includes actions 
or conditions that have a direct impact on individuals (direct 
impacts), as well as those that affect individuals through alteration 
of their habitat or required resources (stressors). The term ``threat'' 
may encompass--either together or separately--the source of the action 
or condition or the action or condition itself.
    However, the mere identification of any threat(s) does not 
necessarily mean that the species meets the statutory definition of an 
``endangered species'' or a ``threatened species.'' In determining 
whether a species meets either definition, we must evaluate all 
identified threats by considering the species' expected response and 
the effects of the threats--in light of those actions and conditions 
that will ameliorate the threats--on an individual, population, and 
species level. We evaluate each threat and its expected effects on the 
species, then analyze the cumulative effect of all of the threats on 
the species as a whole. We also consider the cumulative effect of the 
threats in light of those actions and conditions that will have 
positive effects on the species, such as any existing regulatory 
mechanisms or conservation efforts. The Secretary determines whether 
the species meets the definition of an ``endangered species'' or a 
``threatened species'' only after conducting this cumulative analysis 
and describing the expected effect on the species now and in the 
foreseeable future.
    The Act does not define the term ``foreseeable future,'' which 
appears in the statutory definition of ``threatened species.'' Our 
implementing regulations at 50 CFR 424.11(d) set forth a framework for 
evaluating the foreseeable future on a case-by-case basis. The term 
``foreseeable future'' extends only so far into the future as we can 
reasonably determine that both the future threats and the species' 
responses to those threats are likely. In other words, the foreseeable 
future is the period of time in which we can make reliable predictions. 
``Reliable'' does not mean ``certain''; it means sufficient to provide 
a reasonable degree of confidence in the prediction. Thus, a prediction 
is reliable if it is reasonable to depend on it when making decisions.

[[Page 57050]]

    It is not always possible or necessary to define the foreseeable 
future as a particular number of years. Analysis of the foreseeable 
future uses the best scientific and commercial data available and 
should consider the timeframes applicable to the relevant threats and 
to the species' likely responses to those threats in view of its life-
history characteristics. Data that are typically relevant to assessing 
the species' biological response include species-specific factors such 
as lifespan, reproductive rates or productivity, certain behaviors, and 
other demographic factors.

Analytical Framework

    The SSA report documents the results of our comprehensive 
biological review of the best scientific and commercial data regarding 
the status of these species, including an assessment of the potential 
threats to the species. The SSA report does not represent our decision 
on whether the species should be proposed for listing as endangered or 
threatened species under the Act. However, it does provide the 
scientific basis that informs our regulatory decisions, which involve 
the further application of standards within the Act and its 
implementing regulations and policies.
    To assess the viability of the toothless blindcat and the widemouth 
blindcat, we used the three conservation biology principles of 
resiliency, redundancy, and representation (Shaffer and Stein 2000, pp. 
306-310). Briefly, resiliency is the ability of the species to 
withstand environmental and demographic stochasticity (for example, wet 
or dry, warm or cold years), redundancy is the ability of the species 
to withstand catastrophic events (for example, droughts, large 
pollution events), and representation is the ability of the species to 
adapt to both near-term and long-term changes in its physical and 
biological environment (for example, climate conditions, pathogens). In 
general, species viability will increase with increases in resiliency, 
redundancy, and representation (Smith et al. 2018, p. 306). Using these 
principles, we identified these species' ecological requirements for 
survival and reproduction at the individual, population, and species 
levels, and described the beneficial and risk factors influencing the 
species' viability.
    The SSA process can be categorized into three sequential stages. 
During the first stage, we evaluated both individual species' life-
history needs. The next stage involved an assessment of the historical 
and current condition of each species' demographics and habitat 
characteristics, including an explanation of how the species arrived at 
its current condition. The final stage of the SSA involved making 
predictions about the species' responses to positive and negative 
environmental and anthropogenic influences. Throughout all of these 
stages, we used the best available information to characterize 
viability as the ability of a species to sustain populations in the 
wild over time which we then used to inform our regulatory decision.
    The following is a summary of the key results and conclusions from 
the SSA report; the full SSA report can be found at Docket No. FWS-R2-
ES-2023-0069 on https://www.regulations.gov.

Summary of Biological Status and Threats

    In this discussion, we review the biological condition of the 
toothless blindcat and the widemouth blindcat and their resources, and 
the threats that influence these species' current and future condition, 
in order to assess these species' overall viability and the risks to 
that viability.

Species Needs

Adequate Population Size
    Both species of blindcats are assumed to have potentially numbered 
in the tens of thousands of individuals historically (Trajano 2001, pp. 
145-146; Service 2022, pp. 43-44). Due to the toothless blindcat being 
in a lower trophic level as a detrivore and the widemouth blindcat 
being in a higher trophic level as a predator, we assume the population 
of the widemouth blindcat is smaller than that of the toothless 
blindcat (Trajano 2001, p. 145). Adequate population size at sufficient 
density is needed for both species to access mates for reproduction and 
withstand stochastic events. Mortality events in long-lived, 
reproductively constrained fish populations can have prolonged impacts 
on population demographics, including reduced numbers of sexually 
mature fish, reduced reproductive output, and diminished recruitment of 
younger individuals (Adams 1980, p. 7; Heppell et al. 2005, pp. 213-
214, 217; Graening et al. 2010, pp. 74-75; Whiterod et al. 2018, pp. 
622-626). Representation among various age-classes is needed to support 
recruitment of sexually mature adults to maintain adequate population 
sizes (Adams 1980, pp. 2-7; Poulson 2001, pp. 354-357; Hsieh et al. 
2010, pp. 167-176).
Intact and Interconnected Subterranean Void Space
    The toothless blindcat and widemouth blindcat inhabit subterranean 
voids of sufficient size and connectivity within the Edwards Aquifer. 
The species' occurrence from multiple wells along a southwest to 
northeast trending line in Bexar County suggests that the ranges of 
both species might be relatively continuous. Subterranean networks of 
water-filled conduits can facilitate gene flow through the water-filled 
voids of aquifers (Chippindale 2009, pp. 8-9; V[ouml]r[ouml]s et al. 
2018, p. 217; Corbin 2020, p. 75; Falniowski et al. 2021, pp. 4979-
4980, 4985-4986; Grego and Pe[scaron]i[cacute] 2021, pp. 68, 73-74). 
Both fish species use these connected areas for dispersal, foraging, 
and reproduction (Service 2022, pp. 29-37, 44-45).
Adequate Groundwater Quantity
    Sufficient volumes of groundwater are needed to fill subterranean 
void space and provide dispersal corridors for the species within a 
narrow band of the Edwards Aquifer. The region of the aquifer these 
species inhabit is an area of significant groundwater flow (Maclay and 
Small 1986, p. 66; Hovorka et al. 1996, pp. 50, 54-57; Worthington 
2003, pp. 16, 20, 23-24, 31-32; Hovorka et al. 2004, pp. 19, 42; 
Lindgren et al. 2004, pp. 11, 15, 17-21, 26).
Suitable Water Quality
    Over millions of years, both the toothless blindcat and widemouth 
blindcat have evolved to very deep aquifer conditions, including the 
water quality at these depths. Thus, they likely need water quality 
that matches natural aquifer conditions, including a pH of 7-8, a 
consistent temperature around 28 degrees Celsius ([deg]C) (82 degrees 
Fahrenheit ([deg]F)), specific conductivity between 465-482 
microsiemens per centimeter ([micro]S/cm), and relatively free of 
contaminants (Karnei 1978, pp. 115-116; Service 2022, pp. 37-41).
Chemolithoautotrophic Food Web
    Subterranean systems at great depths and without direct connections 
to the surface are often isolated from surface sources of organic 
matter (Akob and K[uuml]sel 2011, p. 3534; Hubalek et al. 2016, pp. 
2447-2448; It[auml]vaara et al. 2016, pp. 4, 6-8). Instead, food webs 
in these settings may be based on microbial production of organic 
carbon from inorganic materials in a process termed 
chemolithoautotrophy (Engel 2007, pp. 187-188). Microbes involved in 
chemolithoautotrophy include a wide range of bacteria and fungi adapted 
to

[[Page 57051]]

the extreme conditions (such as high pressure and high salinity) of the 
deep subsurface (Amend and Teske 2005, pp. 145-147; Engel 2007, p. 188; 
Akob and K[uuml]sel 2011, pp. 3534, 3236; It[auml]vaara et al. 2016, 
pp. 3-4, 20-22). The toothless blindcat is believed to be a detrivore 
that feeds on bacterial biofilms. The widemouth blindcat is 
hypothesized to be a predator that feeds on groundwater invertebrates 
and potentially suitably sized toothless blindcats. For both species to 
persist, they need a functional chemolithoautotrophic food web in an 
undegraded condition. Because groundwater in the Edwards Aquifer 
originates from precipitation and stream runoff, infusion of surface-
borne nutrients to toothless blindcat and widemouth blindcat habitat 
cannot be discounted and may play some role in the deep aquifer food 
web. However, no accounts detailing surface-borne nutrient presence at 
great aquifer depth have been published to date.

Summary of Threats

    We reviewed the potential threats that could be currently affecting 
the toothless blindcat and the widemouth blindcat. In this proposed 
rule, we will discuss only those threats in detail that could 
meaningfully impact the status of either species (a more in-depth 
analysis of all potential threats can be found in the SSA report 
(Service 2022, pp. 54-61, 87-95). We conducted a thorough analysis of 
threats to groundwater quality in terms of degradation due to 
pollutants and other contaminants and threats to groundwater quantity 
in the form of pumping and climate change. We found that while these 
threats may impact the species, they are not likely to have effects at 
the population or species level. For example, groundwater contamination 
has the potential to impact the toothless blindcat and widemouth 
blindcat (Service 2022, pp. 60-61). However, because of the depth of 
the species' habitat and the thick impermeable rock layer covering it, 
groundwater contamination is not a primary threat for the status of the 
toothless blindcat or the widemouth blindcat. Similarly, because of the 
depth of the species' habitat, groundwater quantity to support habitat 
for the fishes has not experienced change from historical conditions. 
Aquifer water levels where the blindcats reside show no evidence of 
long-term decline, even at times of prolonged drought and unregulated 
pumping (Maclay 1995, pp. 48, 52; Lindgren et al. 2004, 40-41, 45). In 
addition, management of groundwater withdrawals from the San Antonio 
segment has been in place since the late 1990s (National Research 
Council 2015, pp. 24-27, 29, 32-36; National Academies of Sciences, 
Engineering, and Medicine 2018, pp. 7-8, 109, 152; Hardberger 2019, pp. 
193-194; Payne et al. 2019, p. 199) and pumped volumes have decreased 
since 2008 (Service 2022, pp. 80-81). Flow protection measures are in 
place that principally protect the two largest spring systems in the 
region (Comal Spring and San Marcos Spring systems), but those measures 
also benefit water levels deeper in the aquifer. We also note that, 
while competition with exotic species was identified in our 90-day 
finding (74 FR 66866; December 16, 2009) as a potential threat, a 
thorough review of the literature and consultation with experts 
revealed no evidence of exotic species competing with or otherwise 
impacting either species. The primary threat affecting the status of 
the toothless blindcat and the widemouth blindcat is mortality through 
groundwater well uptake (Factor E).
Groundwater Wells
    Prior to well drilling and extraction of groundwater from the 
Edwards Aquifer in the late 19th century, the toothless blindcat and 
widemouth blindcat were unaffected by anthropogenic surface activities 
given the substantial depth of their habitat and the layers of 
impermeable rock that separated that habitat from the surface. 
Extraction of groundwater from wells represented a new and nearly 
constant stressor impacting both species' populations. Well mortality 
is currently the most direct and observable anthropogenic agent of 
mortality for both species. No toothless blindcat or widemouth blindcat 
expelled from groundwater wells has survived for any extended period, 
and many specimens are ejected mangled and dead due to battering as 
they are forced to the surface.
    In Bexar County, the drilling of wells to meet public supply and 
irrigation demands began in the late 1880s (Livingston et al. 1936, p. 
87; Petitt and George 1956, p. 44). The existence of the toothless 
blindcat and widemouth blindcat was only documented through individual 
fish expelled from groundwater wells in the early 20th century 
(Eigenmann 1919, pp. 397, 399-400; Hubbs and Bailey 1947, pp. 1, 4-11). 
More than 1,500 wells were drilled in Bexar County by 1953, with 250 
wells being large capacity (i.e., 25-76 centimeters (cm) (10-30 in) in 
diameter) (Petitt and George 1956, p. 44; Maclay 1995, p. 43), with 
additional large capacity wells drilled during the 1950s across the 
City of San Antonio and Bexar County (Petitt and George 1956, p. 47; 
Arnow 1959, pp. 24, 29). Until 1996, groundwater extraction in Bexar 
County was completely unregulated, with no restrictions on well 
capacity, volumes of water discharged, or groundwater waste (Miller 
2005, pp. 172-173; Gulley 2015, p. 2; Mace 2019, p. 208). From 1939 to 
2000, annual groundwater withdrawals increased by an average of 
5,550,660 cubic meters (m\3\) (4,500 acre-feet (ac-ft)) per year 
(Lindgren et al. 2004, pp. 35-36). As of September 28, 2022, the Texas 
Water Development Board (2022, unpaginated) lists 307 active wells, at 
depths of more than 300 m (984 ft), that access the artesian zone of 
the Edwards Aquifer in Bexar County.
    The additive effect of anthropogenic mortality on cavefishes has 
been studied for only a few taxa. Cavefish exhibit delayed maturity, 
reduced fecundity, low mortality, and longer lifespans (Pianka 1970, p. 
592; Bichuette and Trajano 2021, p. 2). Because cavefish have few 
offspring, the loss of individuals can have a substantial effect on the 
population; any fish that is killed does not survive to reproduce and 
contribute individuals to the population in the future. The Ozark 
cavefish (Amblyopsis rosae) is one example of the long-lasting impact 
of anthropogenic mortality. After the impact of human threats, 
populations of this species skewed towards older individuals with few 
younger fish present (Service 1989, p. 7; Graening et al. 2010, pp. 74-
75). It was not until the 2000s, after a multi-decade period of 
recovery following the legal prohibition against collection, that a 
larger proportion of younger Ozark cavefish began to appear in 
populations, indicating the cessation of adult capture and the 
successful recruitment of juvenile fish (Graening et al. 2010, pp. 74-
75).
    Several deep-sea fishes also have similar life-history traits as 
cavefishes, including production of fewer and larger eggs, delayed 
sexual maturity, extended longevities, and roles as top predators in 
their respective systems (Poulson 2001, pp. 350, 357). Deep-sea fishes 
have been better studied regarding their response to anthropogenic 
mortality in the form of fishing (Adams 1980, pp. 1-2). Taxa such as 
orange roughy (Hoplostethus atlanticus), Patagonian toothfish 
(Dissostichus eleginoides), and other deep-sea species are very 
sensitive to overfishing (Adams 1980, pp. 4-5; Heppell et al. 2005, pp. 
211-212). Fishing operations often target adult size classes that are 
slow to recruit into populations, which can lead to decreased egg 
production (Heppell et al. 2005, pp. 213-214, 217). As a result, deep-
sea fish populations are slow to recover (i.e., multiple decades) from

[[Page 57052]]

harvesting pressure due to reduced reproductive capacity (Adams 1980, 
p. 7; Whiterod et al. 2018, pp. 622-626).
    The toothless blindcat and widemouth blindcat are among the oldest 
cavefishes in North America (Arce-H et al. 2017, pp. 421, 425). Both 
species, which are some of the deepest dwelling among known cavefishes, 
evolved over millions of years to inhabit very deep aquifer conditions 
(Trajano 2001, p. 140; Fi[scaron]er et al. 2014, p. 976). The 
environmental stressors that typically affect and influence shallow 
subterranean systems (such as flooding, drying of cave passages/
streams, and reduced surface nutrient input) are presumed to not 
operate, or are muted, at the depths where the blindcats occur. The 
deep artesian zone of the Edwards Aquifer provides a stable nutrient 
source (chemolithoautotrophy), consistent water quality (decades old 
groundwater), and very attenuated responses to climatic changes 
(temperature changes) on the surface. Given their long evolutionary 
history, the toothless blindcat and widemouth blindcat have life 
history traits that make them comparable to, if not more sensitive 
than, most other cavefishes in their response to increased loss of 
individuals from their populations.
    While cavefish collection and deep-sea fishing removes larger size-
class fish, loss of toothless blindcats and widemouth blindcats to 
groundwater pumping is plausibly size-indiscriminate. Wells extracting 
groundwater have the potential to remove blindcats at all life stages 
given that motile life stages move through water-saturated voids and 
are thus likely pelagic. Blindcats observed or collected from 
groundwater wells have been juveniles to adults. No eggs or smaller 
size classes (e.g., larvae or fry) of either species have been reported 
to date. It is unlikely that eggs or larvae are not expelled from wells 
along with juveniles and adults. Rather, as larger individuals of both 
species are often severely mangled as they are forced up wells, it is 
probable that similarly transported eggs and larvae are physically 
destroyed and not visually discernable.
    Additionally, unlike discrete collection and fishing events, 
groundwater pumping operates over much longer and sustained time frames 
given demands for groundwater. On an annual basis, wells may operate 
for several continuous months during the growing season for 
agricultural irrigation or nearly year-round for industrial and public 
water supply. The operational lifespan of many Bexar County wells is 
several decades long (e.g., more than 60 years; Service 2022, pp. 70-
80). Consequently, there has likely been very limited opportunity for 
cessation of this stressor where wells intercept toothless blindcat and 
widemouth blindcat habitat. In essence, groundwater wells may 
constitute near-permanent population sinks that can result in the 
mortality of most blindcats at all life stages. Loss of immature and 
adult individuals would constrain population growth through reductions 
in egg production and recruitment of mature adults. The impact of 
groundwater well mortality on toothless blindcat and widemouth blindcat 
populations could be substantial, with the potential to expel 
substantial numbers of toothless blindcats and widemouth blindcats over 
their operational lifespans (see Current Condition, below; Longley and 
Karnei 1978a, p. 36; Longley and Karnei 1978b, p. 39; Service 2022, pp. 
74-79).
    We note that, by using the SSA framework to guide our analysis of 
the scientific information documented in the SSA report, we have 
analyzed the cumulative effects of identified threats and conservation 
actions on these species. To assess the current and future condition of 
these species, we evaluate the effects of all the relevant factors that 
may be influencing the species, including threats and conservation 
efforts. Because the SSA framework considers not just the presence of 
the factors, but to what degree they collectively influence risk to the 
entire species, our assessment integrates the cumulative effects of the 
factors and replaces a standalone cumulative effects analysis.

Conservation Efforts and Regulatory Mechanisms

    In the early 1990s, federal litigation (Sierra Club v. Secretary of 
the Interior, No. MO-91-CA-069, U.S. District Court for the Western 
District of Texas) directed the Service to make determinations 
regarding minimum spring flows and aquifer levels necessary to support 
listed species occurring in the Comal Spring and San Marcos Spring 
systems. The Service produced a recovery plan with that guidance in 
1996 (Service 1996, entire). Another outcome of litigation was the 
creation, in 1993, of the Edwards Aquifer Authority by the State of 
Texas to manage groundwater withdrawals (by nonexempt wells) from the 
San Antonio segment of the Edwards Aquifer (National Research Council 
2015, pp. 24-26; Hardberger 2019, pp. 193-194; Payne et al. 2019, p. 
199). The regulatory area of the Edwards Aquifer Authority includes all 
or a portion of Bexar, Comal, Hays, Medina, and Uvalde Counties.
    The Edwards Aquifer Authority developed a habitat conservation 
plan, approved by the Service in 2013, which provides measures to 
minimize and mitigate take of the nine listed species related to 
covered activities (National Research Council 2015, pp. 27, 29, 32-36; 
RECON Environmental, Inc. 2021, pp. 3-55-3-67). Covered activities 
include groundwater withdrawals for drinking water supplies and 
irrigation as well as recreational activities (National Research 
Council 2015, pp. 32-36; RECON Environmental, Inc. 2021, pp. 2-1-2-16).
    The voluntary minimization and mitigation measures of the plan are 
based on maintaining sufficient minimum flows at Comal Spring and San 
Marcos Spring to sustain listed species during a reoccurrence of 
prolonged drought conditions (National Research Council 2015, pp. 32-
36; National Academies of Sciences, Engineering, and Medicine 2018, pp. 
67-68; Service 2022, p. 64). A review of the Edwards Aquifer Habitat 
Conservation Plan suggests that flow protection measures, including 
groundwater modeling efforts, appear to be effective in meeting flow 
requirements of covered species (National Academies of Sciences, 
Engineering, and Medicine 2018, pp. 7-8, 109, 152). Additionally, 
volumes of groundwater pumped from the San Antonio segment of the 
Edwards Aquifer have decreased since 2008 (Service 2022, pp. 64-65).
    The toothless blindcat and widemouth blindcat are not included in 
the habitat conservation plan because the plan's actions are most 
applicable to spring-dwelling species that inhabit upper portions of 
the Edwards Aquifer (RECON Environmental, Inc., pp. 1-9). However, 
protection of sustained flow at the Comal Spring and San Marcos Spring 
systems does provide overarching protection for species that inhabit 
deep portions of the San Antonio segment. Persistence of surface 
discharge at those spring systems suggests that deeper levels of the 
aquifer have not been appreciably reduced and remain water-saturated 
(Maclay 1995, pp. 48, 52; Lindgren et al. 2004, 40-41, 45).
    An additional conservation measure is land protection efforts by 
the City of San Antonio's Edwards Aquifer Protection Program (Stone and 
Schindel 2002, pp. 38-39; Carnett 2022, unpaginated). In 2000, San 
Antonio passed Proposition 3, an initiative to fund the acquisition 
(fee-simple and conservation easements) of open space

[[Page 57053]]

to protect the contributing and recharge zones of the aquifer in Bexar 
County (Romero 2018, p. 2). That program was reapproved in 2005, 2010, 
and 2015, with additional funds to acquire open space (Reilly and 
Carter 2018, pp. 1-3-1-5). The effort was later expanded to acquire 
lands in Medina and Uvalde Counties that contain larger portions of the 
Edwards Aquifer's contributing and recharge zones (Romero 2018, pp. 5-
6, 8). The dedicated sales tax expired in 2021, with 97,124 hectares 
(240,000 acres) acquired under the Edwards Aquifer Protection Program 
(Carnett 2022, unpaginated). The City of San Antonio recently approved 
an alternative funding stream to support land acquisitions through the 
commitment of $100 million over 10 years (Carnett 2022, unpaginated). 
Protection of open space has the potential to reduce the impacts of 
development (for example, run-off from impervious cover, fertilizer 
applications, and wastewater) and maintain aquifer recharge (Reilly and 
Carter 2018, pp. 3-2, 3-6; Romero 2018, pp. 5-6).
    Several other entities also have measures to protect groundwater 
from contamination. These entities include the Edwards Aquifer 
Authority's Aboveground Storage Tank Program, Agricultural Secondary 
Containment Assistance Program, and Abandoned Well Program, among 
others (Edwards Aquifer Authority 2022, unpaginated). The San Antonio 
Water System implemented several water quality protection measures 
including development regulations (City of San Antonio Code of 
Ordinances, chapter 34, article VI, division 6, Aquifer Protection 
Ordinance No. 81491) for properties over the contributing and recharge 
zones, review of building permits and master development plans, 
regulation of underground storage tanks, and commercial/industrial 
compliance (San Antonio Water System 2022, unpaginated).

Current Condition

    To assess the current conditions of the toothless blindcat and 
widemouth blindcat, we established analysis units immediately around 
well sites with documented records of the toothless blindcat or 
widemouth blindcat (``immediate area analysis units''), as well as a 
larger area encompassing these smaller units (``potential area of 
occurrence'') in order to assess threats to the fishes in a more 
spatially extensive area with a potentially contiguous subterranean 
system of voids within the aquifer. Neither of these units define 
populations but rather geographic areas we presume are areas of 
potential occupancy or areas that are important to or could influence 
both species' survival. The SSA report further details the methodology 
and rationale for creating these units (Service 2022, pp. 67-68).
    Eight wells that historically produced toothless blindcat (six 
wells) and widemouth blindcat (four wells; two of which overlap with 
the toothless blindcat wells) have either been capped, plugged, or 
destroyed. Three wells that produced toothless blindcats (one of which 
also produced widemouth blindcats) are presumed to still operate, as we 
do not have access to the wells to confirm, nor do we have evidence to 
the contrary. Including these three wells, the immediate area analysis 
units contain a combined total of 27 active groundwater wells. Most of 
these wells are for agricultural irrigation or public water supply. The 
average age of these wells is 68 years, with the oldest well drilled in 
1933 and the latest in 1985. Seventeen wells in the analysis units have 
been abandoned, plugged, or destroyed, including historical blindcat 
wells. Besides the documented blindcat wells in the analysis units, 
only 1 of the 24 active wells has ever been sampled for blindcats due 
to lack of access.
    In the larger potential area of occurrence, a total of 82 active 
groundwater wells are established, including the active blindcat wells. 
Most of these wells are used for irrigation, public water supply, and 
industrial purposes. Primary water uses of the remaining wells are for 
aquaculture, domestic purposes, and livestock. Average age of active 
wells is 66 years, with the earliest wells drilled in 1915 and most 
recent in 2020. There are 36 abandoned, plugged, or destroyed wells in 
the potential area of occurrence. The four wells that have been sampled 
in this area showed no evidence of either blindcat species (Karnei 
1978, pp. 68-70; Zara Environmental 2010, p. 68; 2020, p. 10).
Well Mortality Estimates
    Researchers who have sampled groundwater wells for the toothless 
blindcat and widemouth blindcat have developed catch-per-unit-effort 
estimates for their sampling efforts (Longley and Karnei 1978a, pp. 35-
36; 1978b, pp. 36, 38-40; Zara Environmental 2020, pp. 23-27). Catch 
per unit effort was expressed as volume of groundwater exiting a well 
to produce one individual of either species. Available estimates were 
based on surveys of toothless blindcat and widemouth blindcat 
populations that had already been subjected to several decades of 
unregulated groundwater extraction. The status of both blindcat 
species' populations prior to groundwater pumping is unknown, although 
it is known that both species experienced mortality once wells were 
established. It is plausible that, at the time of survey efforts (late 
1970s and 2008 to 2014), toothless blindcat and widemouth blindcat 
population resiliency had already been diminished to some extent from 
past well mortality.
    We assume that a higher catch per unit effort at a well, or lower 
volume of groundwater required to produce a single individual, may 
reflect larger blindcat populations. The highest catch per unit effort 
for both the toothless blindcat and widemouth blindcat comes from 
estimates for the Artesia Pump Station Well, with one toothless 
blindcat caught with every 65,000 m\3\ (53 ac-ft) of groundwater and 
one widemouth blindcat caught with every 129,515 m\3\ (105 ac-ft) of 
groundwater (see Table 1 below; Longley and Karnei 1978a, pp. 35-36; 
1978b, pp. 36, 38-40).
    We apply those estimates of catch per unit effort to estimate 
blindcat well mortality. These estimates of blindcat well mortality do 
not account for variability in distribution and extent of suitable 
blindcat habitat, fish abundances by site, well size and discharge 
capacity, periods of discharge (intermittent or constant), location of 
well casing relative to potential habitat, and reporting of discharged 
volumes. Complete data on those and other variables are not available.
    Estimates of well mortality also only apply to assumed losses of 
larger juvenile and adult fishes. Catch per unit effort has never been 
developed for larvae and very small juveniles. The following estimates 
of well mortality will therefore be underestimates, as no data exist on 
loss of those life stages. Research on other cavefishes and deep-sea 
fishes with similar life history traits suggests that sustained loss of 
individuals, especially sexually mature fish, can result in reduced 
population sizes and changes in demographic structure.
    To estimate average annual mortality, we examined pumped 
groundwater volume data available for 51 wells in the potential area of 
occurrence between the years of 2010 to 2017 (Edwards Aquifer Authority 
2021, unpaginated). Using the annual average volume of groundwater 
pumped from all 51 wells, 10,401,411 m\3\ (8,433 ac-ft), multiplied by 
the estimated catch per unit effort, 159 toothless blindcats and 80 
widemouth blindcats may have been expelled from wells annually. This is 
likely an underestimate of losses, as it does not

[[Page 57054]]

include losses of other immature stages, such as larvae or fry. These 
numbers could be higher still considering the remaining active wells 
for which pumped data are not available. Abandoned and plugged wells 
would have also contributed to past mortality during their operational 
lifespans.
    Most wells in the potential area of occurrence have been in 
operation for multiple decades (average age of 66 years). To illustrate 
the potential total loss of blindcats to wells operated over several 
decades, we assigned the average annual volume discharged (calculated 
from three wells from 2010 to 2017) to all wells for all years between 
the completion of a well to 2021 (the latest year for which data were 
available). As we assume the blindcats have long lifespans, the 
likelihood that individuals will encounter the capture zone of an 
active groundwater well increases over time. Wells operating over 
several decades, and discharging relatively moderate volumes of 
groundwater, could result in the loss of over a thousand toothless 
blindcats and several hundred widemouth blindcats per individual well 
(see Table 1 below, Service 2022, p. 77).

      Table 1--Estimated Potential Loss of Toothless Blindcats and Widemouth Blindcats to Groundwater Wells
----------------------------------------------------------------------------------------------------------------
                                                                                                       Total
                                                                                                     estimated
                                                                                                     number of
                                                                                    Individuals     individuals
                    Species                     Volume to produce one individual   lost per year    lost in 51
                                                                                     per well      wells within
                                                                                                  potential area
                                                                                                   of occurrence
----------------------------------------------------------------------------------------------------------------
Toothless blindcat............................  65,000 m \3\....................             159         535,194
                                                (53 ac-ft)......................
Widemouth blindcat............................  129,515 m \3\...................              80         269,280
                                                (105 ac-ft).....................
----------------------------------------------------------------------------------------------------------------
Estimates are for the wells within the potential area of occurrence with water volume data (n = 51), given
  operational lifespan (average age of 66 years), and catch per unit effort reported for Artesia Pump Station
  Well (Longley and Karnei 1978a, pp. 35-36; 1978b, pp. 36, 38-40).

    In addition to the estimated loss from moderate capacity wells, 
greater capacity wells have been drilled in or near the potential area 
of occurrence, but data are lacking regarding their historical 
discharge volumes. The following mortality estimates for larger 
capacity wells further illustrate the potential impact high volume 
wells could have on blindcat numbers over decades of operation.
    In 1941, San Antonio Public Service Company Well 4 was drilled to a 
depth of 314 m (1,032 ft) (Livingston 1942, p. 1; Petitt and George 
1956, p. 47). That well is approximately 2.4 km (1.5 mi) to the 
northeast of Bexar Metropolitan Water District Well (a widemouth 
blindcat locality) and 7.5 km (4.7 mi) to the southwest of the Artesia 
Pump Station Well (a toothless blindcat and widemouth blindcat 
locality). It is conceivable that blindcat habitat extended to that 
location, although the well has never been sampled for either fish 
species.
    Flow at San Antonio Public Service Company Well 4 has been recorded 
at 1.05 m \3\ per second (m \3\/sec) (37 cubic feet per second (ft \3\/
sec)) (Livingston 1942, pp. 3-4). Flow at that rate over 12 months 
would result in discharge of 33,134,800 m \3\ (26,863 ac-ft) of 
groundwater and potentially 507 toothless and/or 266 widemouth 
blindcats per year. If that well operated at that capacity over its 81-
year operational lifespan, 41,055 toothless blindcats and 20,723 
widemouth blindcats could have potentially been expelled from the well. 
Well 4 is still in operation based on Texas Water Development Board 
records.
    In 1891, the first of a series of 20 to 30 cm (8 to 12 in) diameter 
wells were drilled in what would become the Market Street Pump Station 
(Ewing 2000, pp. 13, 15, 22; Eckhardt 2016, unpaginated). The 1891 well 
was 271 m (890 ft) deep and produced 4,144,499 m \3\ (3,360 ac-ft) of 
groundwater per year (Ewing 2000, pp. 13, 22). Three additional wells 
were drilled in 1894, one well with an annual pumped capacity of 
7,598,248 m \3\ (6,160 ac-ft) and two wells at 4,144,499 m \3\ (3,360 
ac-ft) (Ewing 2000, p. 22). The total annual pumping capacity of these 
four wells would have been 20,031,745 m \3\ (16,240 ac-ft). If 
blindcats entered the capture zones of these wells, 305 toothless 
blindcats and 155 widemouth blindcats could have been discharged per 
year.
    By 1924, the Market Street pump station had 12 wells with a 
combined capacity of pumping 59,404,485 m \3\ (48,160 ac-ft) per year 
(Ewing 2000, p. 15). The pump station's 1924 capacity of 59,404,485 m 
\3\ (48,160 ac-ft) could have resulted in the discharge of 9,086 
toothless blindcats and 4,587 widemouth blindcats over a 10-year 
period. At that same rate, from 1924 to 2022, 89,051 toothless 
blindcats and 44,491 widemouth blindcats would have been expelled from 
wells over that 98-year period. The Market Street pump station is still 
in operation today with several large capacity wells (Eckhardt 2016, 
unpaginated).
    While these scenarios of blindcat losses due to wells are 
hypothetical estimates, they provide insight into the scale of well 
mortality for the toothless blindcat and widemouth blindcat. We know 
that both species are ejected by groundwater wells and die. It is 
evident that wells extracting water from the artesian zone remove 
blindcats and that large capacity wells have the potential to expel 
thousands of individuals over a well's operational lifespan. However, 
the location and depth of wells influence their ability to affect 
blindcat populations; only certain wells will intercept areas occupied 
by toothless and/or widemouth blindcats. That said, very productive 
groundwater wells likely intercept larger water-filled voids that would 
serve as blindcat habitat (Maclay 1995, p. 43).
Conclusions
    The most significant stressor to populations of the toothless and 
widemouth blindcats is mortality due to groundwater pumping. 
Individuals of both species are forced up artesian and pumped wells 
where they are physically damaged and killed. Wells with long 
operational lifespans could have resulted in the deaths of thousands to 
tens of thousands of individuals. All life stages of the blindcats are 
expected to experience mortality due to the action of groundwater 
wells. The greatest loss of

[[Page 57055]]

blindcats potentially occurred from the early 1940s into the early 
1960s, when the largest number of groundwater wells were drilled in the 
potential area of occurrence within the Edwards Aquifer.
    The widemouth blindcat has not been observed from any well since 
1984. Due to groundwater pumping, the species may have declined to 
undetectable numbers (Ferretti et al. 2008, pp. 960-962) or become 
functionally extinct (i.e., permanent reproductive failure prior to 
true extinction; Ricciardi et al. 1998, p. 617; Delord 2007, p. 659; 
Bull et al. 2009, p. 419; Roberts et al. 2017, p. 1193). Toothless 
blindcats, however, have been taken from the Aldridge 209 Well most 
years between 2008 and 2013 and from 2020 to 2022. The species appears 
to be persisting in this area but seemingly in low numbers. Between 
2008 and 2013, material potentially representing 13 individual 
toothless blindcats was taken from the Aldridge 209 Well (Zara 
Environmental 2020, pp. 11, 18-20). Between 2021 and 2022, material 
potentially comprising four toothless blindcats was taken from the same 
well (Diaz 2021, p. 29). Whether abundance of the species at that site 
has declined over the well's 67-year operational lifespan is unknown. 
We assume that numbers of the toothless blindcats at the Aldridge 209 
Well are likely lower than prior to 1955, when the well was first 
drilled. The next most recent records for the toothless blindcat are at 
Tschirhart Well in 2010. The status of both species at other wells is 
unknown, as they remain unsampled since the late 1970s to 1980s due to 
lack of sampling access.
    While pumping has resulted in the directly mortality of both 
species, groundwater quantity to support habitat for the fishes has not 
experienced change from historical conditions. In contrast to surface 
aquifer levels, which occasionally decline, the exceedingly deep 
aquifer water levels where the fishes reside show no evidence of long-
term decline, even at times of prolonged drought and unregulated 
pumping (Maclay 1995, pp. 48, 52; Lindgren et al. 2004, 40-41, 45). In 
addition, management of groundwater withdrawals from the San Antonio 
segment has been in place since the late 1990s (Service 2022, pp. 62-
66) and pumped volumes have decreased since 2008 (Service 2022, pp. 64-
65). Flow protection measures are in place that principally protect the 
Comal Spring and San Marcos Spring systems, but those measures also 
benefit water levels deeper in the aquifer. Groundwater contamination 
does not appear to have been a widespread or prevalent stressor for 
either species. In terms of drinking water standards, contaminants in 
the San Antonio segment occur in relatively low concentrations. The 
presence of contaminants also decreases with depth in the aquifer where 
older water is less affected by contamination. Complete analyses of the 
impact of the threats of groundwater quantity, climate change, and 
contamination on the toothless blindcat and the widemouth blindcat can 
be found in the SSA report (Service 2022, pp. 81-85).
    Based on available information, we expect that the resiliency of 
both species' populations has been reduced from pre-1950 levels, the 
period of new groundwater well establishment in the analysis unit. 
Although populations of the toothless blindcat and widemouth blindcat 
have been postulated as large (Longley and Karnei 1978a, p. 36; 1978b, 
p. 39; Trajano 2001, pp. 145-146), the extensive estimated mortality 
from groundwater wells has likely taken a toll on those potential 
numbers. Additionally, because the toothless blindcat and the widemouth 
blindcat exist as single sympatric subterranean populations, both 
species effectively lack redundancy and have limited representation. 
This places the toothless and widemouth blindcats at greater risk from 
stochastic events and anthropogenic stressors, such as groundwater well 
mortality. Well mortality has likely reduced the abundance of both 
blindcats. Furthermore, the life history traits of both species suggest 
that sustained loss of individuals, especially sexually mature fish, 
can result in reduced population sizes and changes in demographic 
structure in the form of lower numbers of sexually mature fish, reduced 
reproductive output, and diminished recruitment of younger individuals.

Future Condition

    As part of the SSA, we evaluated the future conditions of the 
toothless blindcat and widemouth blindcat by examining the most 
plausible future projections for human population growth, groundwater 
demands, and climate change. Our projections show ongoing well 
mortality through groundwater pumping, but no significant change to 
toothless blindcat and widemouth blindcat habitat due to groundwater 
quality and quantity (Service 2022, pp. 81-86). Because we determined 
that the current conditions of both species are consistent with an 
endangered species (see Determination of the Toothless Blindcat's and 
Widemouth Blindcat's Status, below), we are not presenting the results 
of the future scenarios in this proposed rule. Please refer to the SSA 
report (Service 2022, pp. 86-95) for the full analysis of future 
scenarios.

Determination of the Toothless Blindcat's and Widemouth Blindcat's 
Status

    Section 4 of the Act (16 U.S.C. 1533) and its implementing 
regulations (50 CFR part 424) set forth the procedures for determining 
whether a species meets the definition of an endangered species or a 
threatened species. The Act defines an ``endangered species'' as a 
species in danger of extinction throughout all or a significant portion 
of its range, and a ``threatened species'' as a species likely to 
become an endangered species within the foreseeable future throughout 
all or a significant portion of its range. The Act requires that we 
determine whether a species meets the definition of an endangered 
species or a threatened species because of any of the following 
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.

Status Throughout All of Their Ranges

    We find that mortality resulting from the pumping of groundwater 
wells (Factor E) is the primary threat to both species. The species 
occupy a limited range, and populations of both species have likely 
been severely reduced since the introduction of groundwater wells in 
the late 19th to early 20th century. There are currently 82 active 
groundwater wells in the potential area of occurrence (Service 2022, p. 
72). No toothless blindcat or widemouth blindcat expelled from 
groundwater wells has survived for any extended period, and many 
specimens are ejected mangled and dead due to battering as they are 
forced to the surface. Discharge and sampling data indicate an 
individual well operating over several decades (that is, since the 
1950s), and discharging relatively moderate volumes of groundwater 
could conservatively result in losses of over a thousand toothless 
blindcats and several hundred widemouth blindcats.
    These losses of individual fish to groundwater wells over time 
suggest that both species were, and will continue to be, impacted from 
actively pumped wells. Although population sizes for the toothless 
blindcat and widemouth blindcat may have historically been large, we 
project that

[[Page 57056]]

thousands to tens of thousands of fish have been lost to groundwater 
wells since the early 1900s, and that the resiliency of both species' 
populations has been reduced. Both the toothless blindcat and the 
widemouth blindcat are long-lived and pelagic, and thus more likely to 
encounter a well over their lifespan and be captured by well uptake. 
These species have life-history traits that limit reproductive capacity 
and recruitment, as documented in other cavefish species. These same 
traits make the blindcats more susceptible to long-lasting population 
impacts from well mortality losses.
    The widemouth blindcat has not been observed at a well since the 
mid-1980s, and toothless blindcat has only been expelled from a single 
groundwater well multiple times between 2008 and 2013 and from 2020 to 
2022. The toothless blindcat thus appears to be persisting at this 
location in low numbers. Well mortality has likely reduced the 
abundances of both blindcats along with effects on demographic 
structure in the form of lower numbers of sexually mature fish, reduced 
reproductive output, and diminished recruitment of younger individuals. 
Given these impacts and the limited range of both species, it is 
unlikely that even relatively robust populations of the toothless 
blindcat and widemouth blindcat could indefinitely sustain continued 
losses from well mortality. Both species have limited redundancy and 
representation, making the loss of resiliency from well mortality 
particularly detrimental.
    After evaluating threats to the species and assessing the 
cumulative effect of the threats under the Act's section 4(a)(1) 
factors, we conclude that both species have experienced and continue to 
experience the deleterious impacts of well mortality to such an extent 
that both species are currently in danger of extinction, rather than at 
some point in the foreseeable future. Therefore, both species meet the 
Act's definition of an endangered species rather than that of a 
threatened species. Thus, after assessing the best available 
information, we determine that both the toothless blindcat and the 
widemouth blindcat are in danger of extinction throughout all of their 
ranges.

Status Throughout a Significant Portion of Their Ranges

    Under the Act and our implementing regulations, a species may 
warrant listing if it is in danger of extinction or likely to become so 
in the foreseeable future throughout all or a significant portion of 
its range. We have determined that the toothless blindcat and widemouth 
blindcat are in danger of extinction throughout all of their ranges and 
accordingly did not undertake an analysis of any significant portion of 
their ranges. Because the toothless blindcat and widemouth blindcat 
warrant listing as endangered throughout all of their ranges, our 
determination does not conflict with the decision in Center for 
Biological Diversity v. Everson, 435 F. Supp. 3d 69 (D.D.C. 2020), 
which vacated the provision of the Final Policy on Interpretation of 
the Phrase ``Significant Portion of Its Range'' in the Endangered 
Species Act's Definitions of ``Endangered Species'' and ``Threatened 
Species'' (79 FR 37578; July 1, 2014) providing that if the Service 
determines that a species is threatened throughout all of its range, 
the Service will not analyze whether the species is endangered in a 
significant portion of its range.

Determination of Status

    Our review of the best available scientific and commercial 
information indicates that both the toothless blindcat and widemouth 
blindcat meet the Act's definition of an endangered species. Therefore, 
we propose to list both the toothless blindcat and the widemouth 
blindcat as endangered species in accordance with sections 3(6) and 
4(a)(1) of the Act.

Available Conservation Measures

    Conservation measures provided to species listed as endangered or 
threatened species under the Act include recognition as a listed 
species, planning and implementation of recovery actions, requirements 
for Federal protection, and prohibitions against certain practices. 
Recognition through listing results in public awareness, and 
conservation by Federal, State, Tribal, and local agencies, private 
organizations, and individuals. The Act encourages cooperation with the 
States and other countries and calls for recovery actions to be carried 
out for listed species. The protection required by Federal agencies, 
including the Service, and the prohibitions against certain activities 
are discussed, in part, below.
    The primary purpose of the Act is the conservation of endangered 
and threatened species and the ecosystems upon which they depend. The 
ultimate goal of such conservation efforts is the recovery of these 
listed species, so that they no longer need the protective measures of 
the Act. Section 4(f) of the Act calls for the Service to develop and 
implement recovery plans for the conservation of endangered and 
threatened species. The goal of this process is to restore listed 
species to a point where they are secure, self-sustaining, and 
functioning components of their ecosystems.
    The recovery planning process begins with development of a recovery 
outline made available to the public soon after a final listing 
determination. The recovery outline guides the immediate implementation 
of urgent recovery actions while a recovery plan is being developed. 
Recovery teams (composed of species experts, Federal and State 
agencies, nongovernmental organizations, and stakeholders) may be 
established to develop and implement recovery plans. The recovery 
planning process involves the identification of actions that are 
necessary to halt and reverse the species' decline by addressing the 
threats to its survival and recovery. The recovery plan identifies 
recovery criteria for review of when a species may be ready for 
reclassification from endangered to threatened (``downlisting'') or 
removal from protected status (``delisting''), and methods for 
monitoring recovery progress. Recovery plans also establish a framework 
for agencies to coordinate their recovery efforts and provide estimates 
of the cost of implementing recovery tasks. Revisions of the plan may 
be done to address continuing or new threats to the species, as new 
substantive information becomes available. The recovery outline, draft 
recovery plan, final recovery plan, and any revisions will be available 
on our website as they are completed (https://www.fws.gov/program/endangered-species), or from our Austin Ecological Services Field 
Office (see FOR FURTHER INFORMATION CONTACT).
    Implementation of recovery actions generally requires the 
participation of a broad range of partners, including other Federal 
agencies, States, Tribes, nongovernmental organizations, businesses, 
and private landowners. Examples of recovery actions include habitat 
restoration (e.g., restoration of native vegetation), research, captive 
propagation and reintroduction, and outreach and education. The 
recovery of many listed species cannot be accomplished solely on 
Federal lands because their ranges may occur primarily or solely on 
non-Federal lands. To achieve recovery of these species requires 
cooperative conservation efforts on private, State, and Tribal lands.
    If these species are listed, funding for recovery actions will be 
available from a variety of sources, including Federal budgets, State 
programs, and cost-share grants for non-Federal landowners, the

[[Page 57057]]

academic community, and nongovernmental organizations. In addition, 
pursuant to section 6 of the Act, the State of Texas would be eligible 
for Federal funds to implement management actions that promote the 
protection or recovery of the toothless blindcat and widemouth 
blindcat. Information on our grant programs that are available to aid 
species recovery can be found at: https://www.fws.gov/service/financial-assistance.
    Although the toothless blindcat and widemouth blindcat are only 
proposed for listing under the Act at this time, please let us know if 
you are interested in participating in recovery efforts for these 
species. Additionally, we invite you to submit any new information on 
these species whenever it becomes available and any information you may 
have for recovery planning purposes (see FOR FURTHER INFORMATION 
CONTACT).
    Section 7 of the Act is titled Interagency Cooperation and mandates 
all Federal action agencies to use their existing authorities to 
further the conservation purposes of the Act and to ensure that their 
actions are not likely to jeopardize the continued existence of listed 
species or adversely modify critical habitat. Regulations implementing 
section 7 are codified at 50 CFR part 402.
    Section 7(a)(2) states that each Federal action agency shall, in 
consultation with the Secretary, ensure that any action they authorize, 
fund, or carry out is not likely to jeopardize the continued existence 
of a listed species or result in the destruction or adverse 
modification of designated critical habitat. Each Federal agency shall 
review its action at the earliest possible time to determine whether it 
may affect listed species or critical habitat. If a determination is 
made that the action may affect listed species or critical habitat, 
formal consultation is required (see 50 CFR 402.14(a)), unless the 
Service concurs in writing that the action is not likely to adversely 
affect listed species or critical habitat. At the end of a formal 
consultation, the Service issues a biological opinion, containing its 
determination of whether the Federal action is likely to result in 
jeopardy or adverse modification.
    In contrast, section 7(a)(4) of the Act requires Federal agencies 
to confer with the Service on any action which is likely to jeopardize 
the continued existence of any species proposed to be listed under the 
Act or result in the destruction or adverse modification of critical 
habitat proposed to be designated for such species. Although the 
conference procedures are required only when an action is likely to 
result in jeopardy or adverse modification, action agencies may 
voluntarily confer with the Service on actions that may affect species 
proposed for listing or critical habitat proposed to be designated. In 
the event that the subject species is listed or the relevant critical 
habitat is designated, a conference opinion may be adopted as a 
biological opinion and serve as compliance with section 7(a)(2) of the 
Act.
    Examples of discretionary actions for the toothless blindcat and 
the widemouth blindcat that may be subject to conference and 
consultation procedures under section 7 are land management or other 
landscape-altering activities on Federal lands administered by the U.S. 
Department of Agriculture as well as actions on State, Tribal, local, 
or private lands that require a Federal permit (such as a permit from 
the U.S. Army Corps of Engineers under section 404 of the Clean Water 
Act (33 U.S.C. 1251 et seq.) or a permit from the Service under section 
10 of the Act) or that involve some other Federal action (such as 
funding from the Federal Highway Administration, Federal Aviation 
Administration, or the Federal Emergency Management Agency). Federal 
actions not affecting listed species or critical habitat--and actions 
on State, Tribal, local, or private lands that are not federally 
funded, authorized, or carried out by a Federal agency--do not require 
section 7 consultation. Federal agencies should coordinate with the 
local Service field office (see FOR FURTHER INFORMATION CONTACT, above) 
with any specific questions on section 7 consultation and conference 
requirements.
    The Act and its implementing regulations set forth a series of 
general prohibitions and exceptions that apply to endangered wildlife. 
The prohibitions of section 9(a)(1) of the Act, codified at 50 CFR 
17.21, make it illegal for any person subject to the jurisdiction of 
the United States to commit, to attempt to commit, to solicit another 
to commit, or to cause to be committed any of the following: (1) Import 
endangered wildlife into, or export from, the United States; (2) take 
(which includes harass, harm, pursue, hunt, shoot, wound, kill, trap, 
capture, or collect, or to attempt to engage in any such conduct) 
endangered wildlife within the United States or on the high seas; (3) 
possess, sell, deliver, carry, transport, or ship, by any means 
whatsoever, any such wildlife that has been taken illegally; (4) 
deliver, receive, carry, transport, or ship in interstate or foreign 
commerce in the course of commercial activity; or (5) sell or offer for 
sale in interstate or foreign commerce. Certain exceptions to these 
prohibitions apply to employees or agents of the Service, the National 
Marine Fisheries Service, other Federal land management agencies, and 
State conservation agencies.
    We may issue permits to carry out otherwise prohibited activities 
involving endangered wildlife under certain circumstances. Regulations 
governing permits for endangered wildlife are codified at 50 CFR 17.22. 
With regard to endangered wildlife, a permit may be issued for 
scientific purposes, for enhancing the propagation or survival of the 
species, or for take incidental to otherwise lawful activities. The 
statute also contains certain exemptions from the prohibitions, which 
are found in sections 9 and 10 of the Act.
    It is the policy of the Services, as published in the Federal 
Register on July 1, 1994 (59 FR 34272), to identify, to the extent 
known at the time a species is listed, specific activities that will 
not be considered likely to result in violation of section 9 of the 
Act. To the extent possible, activities that will be considered likely 
to result in violation will also be identified in as specific a manner 
as possible. The intent of this policy is to increase public awareness 
of the effect of a proposed listing on proposed and ongoing activities 
within the range of the species proposed for listing.
    At this time, we are unable to identify specific activities that 
would or would not be likely to result in a violation of section 9 of 
the Act beyond what is already clear from the descriptions of 
prohibitions or already excepted through our regulations at 50 CFR 
17.21 (e.g., any person may take endangered wildlife in defense of his 
own life or the lives of others). As discussed above, certain 
activities that are prohibited under section 9 may be permitted under 
section 10 of the Act. Questions regarding whether specific activities 
would constitute a violation of section 9 of the Act should be directed 
to the Austin Ecological Services Field Office (see FOR FURTHER 
INFORMATION CONTACT).

II. Critical Habitat

Background

    Critical habitat is defined in section 3 of the Act as:
    (1) The specific areas within the geographical area occupied by the 
species, at the time it is listed in accordance with the Act, on which 
are found those physical or biological features
    (a) Essential to the conservation of the species, and

[[Page 57058]]

    (b) Which may require special management considerations or 
protection; and
    (2) Specific areas outside the geographical area occupied by the 
species at the time it is listed, upon a determination that such areas 
are essential for the conservation of the species.
    Our regulations at 50 CFR 424.02 define the geographical area 
occupied by the species as an area that may generally be delineated 
around species' occurrences, as determined by the Secretary (i.e., 
range). Such areas may include those areas used throughout all or part 
of the species' life cycle, even if not used on a regular basis (e.g., 
migratory corridors, seasonal habitats, and habitats used periodically, 
but not solely by vagrant individuals).
    Conservation, as defined under section 3 of the Act, means to use 
and the use of all methods and procedures that are necessary to bring 
an endangered or threatened species to the point at which the measures 
provided pursuant to the Act are no longer necessary. Such methods and 
procedures include, but are not limited to, all activities associated 
with scientific resources management such as research, census, law 
enforcement, habitat acquisition and maintenance, propagation, live 
trapping, and transplantation, and, in the extraordinary case where 
population pressures within a given ecosystem cannot be otherwise 
relieved, may include regulated taking.
    Critical habitat receives protection under section 7 of the Act 
through the requirement that each Federal action agency ensure, in 
consultation with the Service, that any action they authorize, fund, or 
carry out is not likely to result in the destruction or adverse 
modification of designated critical habitat. The designation of 
critical habitat does not affect land ownership or establish a refuge, 
wilderness, reserve, preserve, or other conservation area. Such 
designation also does not allow the government or public to access 
private lands. Such designation does not require implementation of 
restoration, recovery, or enhancement measures by non-Federal 
landowners. Rather, designation requires that, where a landowner 
requests Federal agency funding or authorization for an action that may 
affect an area designated as critical habitat, the Federal agency 
consult with the Service under section 7(a)(2) of the Act. If the 
action may affect the listed species itself (such as for occupied 
critical habitat), the Federal agency would have already been required 
to consult with the Service even absent the designation because of the 
requirement to ensure that the action is not likely to jeopardize the 
continued existence of the species. Even if the Service were to 
conclude after consultation that the proposed activity is likely to 
result in destruction or adverse modification of the critical habitat, 
the Federal action agency and the landowner are not required to abandon 
the proposed activity, or to restore or recover the species; instead, 
they must implement ``reasonable and prudent alternatives'' to avoid 
destruction or adverse modification of critical habitat.
    Under the first prong of the Act's definition of critical habitat, 
areas within the geographical area occupied by the species at the time 
it was listed are included in a critical habitat designation if they 
contain physical or biological features (1) which are essential to the 
conservation of the species and (2) which may require special 
management considerations or protection. For these areas, critical 
habitat designations identify, to the extent known using the best 
scientific data available, those physical or biological features that 
are essential to the conservation of the species (such as space, food, 
cover, and protected habitat).
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in areas outside the geographical 
area occupied by the species at the time it is listed, upon a 
determination that such areas are essential for the conservation of the 
species.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific data available. Further, our Policy on 
Information Standards Under the Endangered Species Act (published in 
the Federal Register on July 1, 1994 (59 FR 34271)), the Information 
Quality Act (section 515 of the Treasury and General Government 
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), 
and our associated Information Quality Guidelines provide criteria, 
establish procedures, and provide guidance to ensure that our decisions 
are based on the best scientific data available. They require our 
biologists, to the extent consistent with the Act and with the use of 
the best scientific data available, to use primary and original sources 
of information as the basis for recommendations to designate critical 
habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information from the SSA report and information developed during the 
listing process for the species. Additional information sources may 
include any generalized conservation strategy, criteria, or outline 
that may have been developed for the species; the recovery plan for the 
species; articles in peer-reviewed journals; conservation plans 
developed by States and counties; scientific status surveys and 
studies; biological assessments; other unpublished materials; or 
experts' opinions or personal knowledge.
    Habitat is dynamic, and species may move from one area to another 
over time. We recognize that critical habitat designated at a 
particular point in time may not include all of the habitat areas that 
we may later determine are necessary for the recovery of the species. 
For these reasons, a critical habitat designation does not signal that 
habitat outside the designated area is unimportant or may not be needed 
for recovery of the species. Areas that are important to the 
conservation of the species, both inside and outside the critical 
habitat designation, will continue to be subject to: (1) Conservation 
actions implemented under section 7(a)(1) of the Act; (2) regulatory 
protections afforded by the requirement in section 7(a)(2) of the Act 
for Federal agencies to ensure their actions are not likely to 
jeopardize the continued existence of any endangered or threatened 
species; and (3) the prohibitions found in section 9 of the Act. 
Federally funded or permitted projects affecting listed species outside 
their designated critical habitat areas may still result in jeopardy 
findings in some cases. These protections and conservation tools will 
continue to contribute to recovery of the species. Similarly, critical 
habitat designations made on the basis of the best available 
information at the time of designation will not control the direction 
and substance of future recovery plans, habitat conservation plans, or 
other species conservation planning efforts if new information 
available at the time of those planning efforts calls for a different 
outcome.

Prudency Determination

    Section 4(a)(3) of the Act, as amended, and implementing 
regulations (50 CFR 424.12) require that, to the maximum extent prudent 
and determinable, the Secretary shall designate critical habitat at the 
time the species is determined to be an endangered or threatened 
species. Our regulations (50 CFR 424.12(a)(1)) state that the Secretary 
may, but is not required to, determine that a

[[Page 57059]]

designation would not be prudent in the following circumstances:
    (i) The species is threatened by taking or other human activity and 
identification of critical habitat can be expected to increase the 
degree of such threat to the species;
    (ii) The present or threatened destruction, modification, or 
curtailment of a species' habitat or range is not a threat to the 
species, or threats to the species' habitat stem solely from causes 
that cannot be addressed through management actions resulting from 
consultations under section 7(a)(2) of the Act;
    (iii) Areas within the jurisdiction of the United States provide no 
more than negligible conservation value, if any, for a species 
occurring primarily outside the jurisdiction of the United States;
    (iv) No areas meet the definition of critical habitat; or
    (v) The Secretary otherwise determines that designation of critical 
habitat would not be prudent based on the best scientific data 
available.
    As discussed above, there are no significant habitat-based threats 
that currently, or would in the future, limit habitat for the toothless 
blindcat and the widemouth blindcat. The present or threatened 
destruction, modification, or curtailment of the blindcats' habitat or 
range is not a threat to the species. In light of the particular 
circumstances of these two species, we have determined that designation 
of critical habitat is not prudent. We reach this conclusion largely 
because of the nature of the main threat for these species: direct 
mortality resulting from groundwater well pumping (Factor E). The wells 
constructed in these blindcats' habitat are not affecting the species 
through habitat destruction or modification; instead, it is the 
capture, entrainment, and death of individuals due to the pumping of 
groundwater wells that is a threat to the species. Designation of 
critical habitat would not provide any additional protective measures 
or benefits that address this specific threat. In addition, the 
designation of critical habitat would not provide otherwise unavailable 
information to guide conservation efforts for these species. Therefore, 
a designation of critical habitat would not be advantageous for these 
species.
    Since we have determined that the present or threatened 
destruction, modification, or curtailment of both species' habitat or 
range is not a threat to the toothless blindcat and the widemouth 
blindcat, in accordance with 50 CFR 424.12(a)(1), we determine that 
designation of critical habitat is not prudent for the toothless 
blindcat and the widemouth blindcat.

Required Determinations

Clarity of the Rule

    We are required by E.O.s 12866 and 12988 and by the Presidential 
Memorandum of June 1, 1998, to write all rules in plain language. This 
means that each rule we publish must:
    (1) Be logically organized;
    (2) Use the active voice to address readers directly;
    (3) Use clear language rather than jargon;
    (4) Be divided into short sections and sentences; and
    (5) Use lists and tables wherever possible.
    If you feel that we have not met these requirements, send us 
comments by one of the methods listed in ADDRESSES. To better help us 
revise the rule, your comments should be as specific as possible. For 
example, you should tell us the numbers of the sections or paragraphs 
that are unclearly written, which sections or sentences are too long, 
the sections where you feel lists or tables would be useful, etc.

Government-to-Government Relationship With Tribes

    In accordance with the President's memorandum of April 29, 1994 
(Government-to-Government Relations with Native American Tribal 
Governments; 59 FR 22951), E.O. 13175 (Consultation and Coordination 
with Indian Tribal Governments), and the Department of the Interior's 
manual at 512 DM 2, we readily acknowledge our responsibility to 
communicate meaningfully with federally recognized Tribes on a 
government-to-government basis. In accordance with Secretary's Order 
3206 of June 5, 1997 (American Indian Tribal Rights, Federal-Tribal 
Trust Responsibilities, and the Endangered Species Act), we readily 
acknowledge our responsibilities to work directly with Tribes in 
developing programs for healthy ecosystems, to acknowledge that Tribal 
lands are not subject to the same controls as Federal public lands, to 
remain sensitive to Indian culture, and to make information available 
to Tribes. No Tribal lands were identified within the range of the 
toothless blindcat or widemouth blindcat.

References Cited

    A complete list of references cited in this proposed rule is 
available on the internet at https://www.regulations.gov and upon 
request from the Austin Ecological Services Field Office (see FOR 
FURTHER INFORMATION CONTACT).

Authors

    The primary authors of this proposed rule are the staff members of 
the Fish and Wildlife Service's Species Assessment Team and the Austin 
Ecological Services Field Office.

List of Subjects in 50 CFR Part 17

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

Proposed Regulation Promulgation

    Accordingly, we propose to amend part 17, subchapter B of chapter 
I, title 50 of the Code of Federal Regulations, as set forth below:

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

0
1. The authority citation for part 17 continues to read as follows:

    Authority:  16 U.S.C. 1361-1407; 1531-1544; and 4201-4245, 
unless otherwise noted.

0
2. In Sec.  17.11, in paragraph (h), amend the List of Endangered and 
Threatened Wildlife by adding entries for ``Blindcat, toothless'' and 
``Blindcat, widemouth'' in alphabetical order under FISHES to read as 
follows:


Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

----------------------------------------------------------------------------------------------------------------
                                                                                           Listing citations and
          Common name              Scientific name      Where listed          Status         applicable rules
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                                     Fishes
----------------------------------------------------------------------------------------------------------------
 

[[Page 57060]]

 
                                                  * * * * * * *
Blindcat, toothless............  Trogloglanis        Wherever found....  E                [Federal Register
                                  pattersoni.                                              citation when
                                                                                           published as a final
                                                                                           rule].
Blindcat, widemouth............  Satan eurystomus..  Wherever found....  E                [Federal Register
                                                                                           citation when
                                                                                           published as a final
                                                                                           rule].
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


Wendi Weber,
Acting Director, U.S. Fish and Wildlife Service.
[FR Doc. 2023-17667 Filed 8-21-23; 8:45 am]
BILLING CODE 4333-15-P