30888 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

DEPARTMENT OF THE INTERIOR 

Fish and Wildlife Service 

50 CFR Part 17 

[Docket No. FWS–R2–ES–2018–0021; 

FF09E21000 FXES11110900000 212] 

RIN 1018–BD55 

Endangered and Threatened Wildlife 

and Plants; Designating Texas 

Hornshell Critical Habitat 

AGENCY: Fish and Wildlife Service, 

Interior. 

ACTION: Proposed rule. 

SUMMARY: We, the U.S. Fish and 

Wildlife Service (Service), propose to 

designate critical habitat for the Texas 

hornshell (Popenaias popeii), a 

freshwater mussel, under the 

Endangered Species Act (Act). In total, 

the proposed critical habitat designation 

includes approximately 463.6 river 

miles (745.9 kilometers) in Eddy 

County, New Mexico, and in Culberson, 

Brewster, Terrell, Val Verde, Kinney, 

Maverick, and Webb Counties, Texas. If 

we finalize this rule as proposed, it 

would extend the Act’s protections to 

this species’ critical habitat. The effect 

of this regulation is to designate critical 

habitat for the Texas hornshell under 

the Act. We also announce the 

availability of a draft economic analysis 

of the proposed designation of critical 

habitat. We also are notifying the public 

that we have scheduled an 

informational meeting followed by a 

public hearing on the proposed rule. 

DATES: 

Comment submission: We will accept 

comments on this proposed rule or draft 

economic analysis that are received or 

postmarked on or before August 9, 2021. 

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. 

Public informational meeting and 

public hearing: We will hold a public 

informational session from 5:00 p.m. to 

6:00 p.m., Mountain Time, followed by 

a public hearing from 6:30 p.m. to 8:30 

p.m., Mountain Time, on June 29, 2021. 

ADDRESSES: 

Comment submission: You may 

submit comments on the proposed rule 

or draft economic analysis by one of the 

following methods: 

(1) Electronically: Go to the Federal 

eRulemaking Portal: http://

www.regulations.gov. In the Search box, 

enter FWS–R2–ES–2018–0021 to find 

this proposed rule. You may submit a 

comment by clicking on ‘‘Comment 

Now!’’ 

(2) By hard copy: Submit by U.S. mail 

to: Public Comments Processing, Attn: 

FWS–R2–ES–2018–0021; U.S. Fish and 

Wildlife Service Headquarters, MS: 

BPHC, 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 http://

www.regulations.gov. This generally 

means that we will post any personal 

information you provide us (see the 

Information Requested section below for 

more information). 

Public informational meeting and 

public hearing: The public 

informational meeting and the public 

hearing will be held virtually using the 

Zoom platform. See Public Hearing, 

below, for more information. 

Document availability: The draft 

economic analysis is available at https:// 

www.fws.gov/southwest/es/ 

TexasCoastal/, at http://

www.regulations.gov in Docket No. 

FWS–R2–ES–2018–0021, and at the 

Texas Coastal Ecological Services Field 

Office (see FOR FURTHER INFORMATION

CONTACT). 

The coordinates or plot points or both 

from which the maps are generated are 

included in the administrative record 

for this critical habitat designation and 

are available at https://www.fws.gov/ 

southwest/es/TexasCoastal/, at http://

www.regulations.gov in Docket No. 

FWS–R2–ES–2018–0021, and at the 

Texas Coastal Ecological Services Field 

Office (see FOR FURTHER INFORMATION

CONTACT). Any additional tools or 

supporting information that we may 

develop for this critical habitat 

designation will also be available at the 

Service website and field office set out 

above, and may also be included in the 

preamble of the final rule and/or at 

http://www.regulations.gov. 

FOR FURTHER INFORMATION CONTACT: 

Chuck Ardizzone, U.S. Fish and 

Wildlife Service, Texas Coastal 

Ecological Services Field Office, 17629 

El Camino Real #211, Houston, TX 

77058; by telephone 281–286–8282; or 

by facsimile 281–488–5882. Persons 

who use a telecommunications device 

for the deaf (TDD) may call the Federal 

Relay Service at 800–877–8339. 

SUPPLEMENTARY INFORMATION: 

Executive Summary 

Why we need to publish a rule. Under 

the Endangered Species Act, critical 

habitat must be designated, to the 

maximum extent prudent and 

determinable, for all species determined 

to be endangered or threatened. The 

Lists of Endangered and Threatened 

Wildlife and Plants are in title 50 of the 

Code of Federal Regulations (CFR) in 

part 17 (50 CFR 17.11(h) for wildlife and 

50 CFR 17.12(h) for plants). 

Designations and revisions of critical 

habitat can only be completed by 

issuing a rule. 

What this document does. This 

document proposes the designation of 

critical habitat for the Texas hornshell 

and announces the availability of the 

draft economic analysis. The Texas 

hornshell has been listed as an 

endangered species under the Act. This 

rule proposes designation of critical 

habitat necessary for the conservation of 

the species. 

The basis for our action. Under the 

Endangered Species Act, any species 

that is determined to be a threatened or 

endangered species shall, to the 

maximum extent prudent and 

determinable, have habitat designated 

that is considered to be critical habitat. 

Section 4(b)(2) of the Endangered 

Species Act states that the Secretary 

shall designate and make revisions to 

critical habitat on the basis of the best 

available scientific data after taking into 

consideration the economic impact, the 

impact on national security, and any 

other relevant impact of specifying any 

particular area as critical habitat. The 

Secretary may exclude an area from 

critical habitat if he determines that the 

benefits of such exclusion outweigh the 

benefits of specifying such area as part 

of the critical habitat, unless he 

determines, based on the best scientific 

data available, that the failure to 

designate such area as critical habitat 

will result in the extinction of the 

species. 

Supporting analyses. We prepared an 

analysis of the economic impacts of the 

proposed critical habitat designation 

and hereby announce the availability of 

the draft economic analysis for public 

review and comment. 

Our species status assessment report 

(SSA report) documents the results of 

the comprehensive biological status 

review for the Texas hornshell and 

provides an account of the species’ 

overall viability through forecasting of 

the species’ condition in the future 

(Service 2018, entire). Additionally, the 

SSA report contains our analysis of 

required habitat and the existing 

conditions of that habitat. 

Peer review. We sought comments 

from independent specialists on the 

SSA report to ensure that our critical 

habitat proposal is based on 

scientifically sound data and analyses. 

We received feedback from four 

scientists with expertise in freshwater 

mussel biology, ecology, and genetics as 

peer review of the SSA report. The 

reviewers were generally supportive of 


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our approach and made suggestions and 

comments that strengthened our 

analysis. We incorporated these 

comments into the SSA report, which 

can be found at http://

www.regulations.gov under Docket No. 

FWS–R2–ES–2018–0021. 

Information Requested 

We intend that any final action 

resulting from this proposed rule will be 

based on the best scientific data 

available and be as accurate and as 

effective as possible. Therefore, we 

request comments or information from 

other concerned government agencies, 

the scientific community, industry, or 

any other interested party concerning 

this proposed rule. Because we will 

consider all comments and information 

received during the comment period, 

our final determinations may differ from 

this proposal. 

We particularly seek comments 

concerning: 

(1) The reasons why we should or 

should not designate habitat as ‘‘critical 

habitat’’ under section 4 of the Act (16 

U.S.C. 1531 et seq.) including 

information to inform the following 

factors such that a designation of critical 

habitat may be determined to be not 

prudent: 

(a) 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; 

(b) 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; 

(c) 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; 

(d) No areas meet the definition of 

critical habitat. 

(2) Specific information on: 

(a) The amount and distribution of 

Texas hornshell habitat; 

(b) What areas that were occupied at 

the time of listing and that contain the 

physical or biological features essential 

to the conservation of the species 

should be included in the designation 

and why; 

(c) Special management 

considerations or protection that may be 

needed in critical habitat areas we are 

proposing, including managing for the 

potential effects of climate change; and 

(d) What areas not occupied at the 

time of listing are essential for the 

conservation of the species. We 

particularly seek comments regarding: 

(i) Whether occupied areas are 

inadequate for the conservation of the 

species; and, 

(ii) Specific information that supports 

the determination that unoccupied areas 

will, with reasonable certainty, 

contribute to the conservation of the 

species and, contain at least one 

physical or biological feature essential 

to the conservation of the species. 

(3) Land use designations and current 

or planned activities in the subject areas 

and their possible impacts on proposed 

critical habitat. 

(4) Information on the projected and 

reasonably likely impacts of climate 

change on the Texas hornshell and 

proposed critical habitat. 

(5) Any probable economic, national 

security, or other relevant impacts of 

designating any area that may be 

included in the final designation, and 

the benefits of including or excluding 

areas that may be impacted. 

(6) Information on the extent to which 

the description of probable economic 

impacts in the draft economic analysis 

is a reasonable estimate of the likely 

economic impacts. 

(7) Whether any specific areas we are 

proposing for critical habitat 

designation should be considered for 

exclusion under section 4(b)(2) of the 

Act, and whether the benefits of 

potentially excluding any specific area 

outweigh the benefits of including that 

area under section 4(b)(2) of the Act, in 

particular for those covered by the 

Candidate Conservation Agreement 

(CCA) and Candidate Conservation 

Agreement with Assurances (CCAA) for 

the Texas hornshell in the Black and 

Delaware Rivers in New Mexico and 

Texas. 

(8) Whether any lands should be 

considered for exclusion under section 

4(b)(2) of the Act for national security 

reasons, whether such exclusion is or is 

not appropriate, and whether the 

benefits of excluding any specific area 

outweigh the benefits of including that 

area as critical habitat and why. 

(9) Whether lands owned by the 

Kickapoo Indian Reservation of Texas 

should be considered for exclusion 

under section 4(b)(2) of the Act, whether 

such exclusion is or is not appropriate, 

and whether the benefits of excluding 

any specific area outweigh the benefits 

of including that area as critical habitat 

and why. 

(10) The likelihood of adverse social 

reactions to the designation of critical 

habitat, as discussed in the associated 

documents of the draft economic 

analysis, and how the consequences of 

such reactions, if likely to occur, would 

relate to the conservation and regulatory 

benefits of the proposed critical habitat 

designation. 

(11) Whether we could improve or 

modify our approach to designating 

critical habitat in any way to provide for 

greater public participation and 

understanding, or to better 

accommodate public concerns and 

comments. 

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. 

All comments submitted 

electronically via http://

www.regulations.gov will be presented 

on the website in their entirety as 

submitted. For comments submitted via 

hard copy, we will post your entire 

comment—including your personal 

identifying information—on http://

www.regulations.gov. You may request 

at the top of your document that we 

withhold personal information such as 

your street address, phone number, or 

email address from public review; 

however, we cannot guarantee that we 

will be able to do so. 

Comments and materials we receive, 

as well as supporting documentation we 

used in preparing this proposed rule, 

will be available for public inspection 

on http://www.regulations.gov. 

Previous Federal Actions 

All previous Federal actions are 

described in the final rule listing the 

Texas hornshell as an endangered 

species under the Act published in the 

Federal Register on February 9, 2018 

(83 FR 5720). 

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 

(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. 


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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 Federal agencies 

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 

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 

does not allow the government or public 

to access private lands. Such 

designation does not require 

implementation of restoration, recovery, 

or enhancement measures by nonFederal landowners. Where a landowner 

requests Federal agency funding or 

authorization for an action that may 

affect a listed species or critical habitat, 

the consultation requirements of section 

7(a)(2) of the Act would apply, but even 

in the event of a destruction or adverse 

modification finding, the obligation of 

the Federal action agency and the 

landowner is not to restore or recover 

the species, but to 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 

and commercial data available, those 

physical or biological features that are 

essential to the conservation of the 

species (such as space, food, cover, and 

protected habitat). In identifying those 

physical or biological features that occur 

in specific areas, we focus on the 

specific features that are essential to 

support the life-history needs of the 

species, including but not limited to, 

water characteristics, soil type, 

geological features, prey, vegetation, 

symbiotic species, or other features. A 

feature may be a single habitat 

characteristic, or a more complex 

combination of habitat characteristics. 

Features may include habitat 

characteristics that support ephemeral 

or dynamic habitat conditions. Features 

may also be expressed in terms relating 

to principles of conservation biology, 

such as patch size, distribution 

distances, and connectivity. 

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. When designating critical 

habitat, the Secretary will first evaluate 

areas occupied by the species. The 

Secretary will only consider unoccupied 

areas to be essential where a critical 

habitat designation limited to 

geographical areas occupied by the 

species would be inadequate to ensure 

the conservation of the species. In 

addition, for an unoccupied area to be 

considered essential, the Secretary must 

determine that there is a reasonable 

certainty both that the area will 

contribute to the conservation of the 

species and that the area contains one 

or more of those physical or biological 

features essential to 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) section 9 

of the Act’s prohibitions on taking any 

individual of the species, including 

taking caused by actions that affect 

habitat. Federally funded or permitted 

projects affecting listed species outside 

their designated critical habitat areas 

may still result in findings that the 

action jeopardizes the continued 

existence of the species in some cases. 

These protections and conservation 

tools will continue to contribute to 

recovery of this 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 


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available at the time of these planning 

efforts calls for a different outcome. 

Habitat Outside the United States 

Within the identified geographical 

area occupied at the time of listing (see 

below, Areas Occupied at the Time of 

Listing), the habitat areas used by the 

species are in Texas, New Mexico, and 

Mexico. Because we do not designate as 

critical habitat areas outside the United 

States (50 CFR 424.12(g)), we did not 

examine areas on the Mexican side of 

the Rio Grande; the critical habitat 

extends only as far into the river as the 

United States’ jurisdictional boundary, 

i.e., to the middle of the river. However, 

conservation of habitat that meets the 

conditions described in this designation 

in Mexico may be important to recovery 

of the species. 

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 

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. 

We did not identify any of the factors 

above to apply to the Texas hornshell. 

Therefore, we find designation of 

critical habitat is prudent for the 

species. 

Critical Habitat Determinability 

Having determined that designation is 

prudent, under section 4(a)(3) of the Act 

we must find whether critical habitat for 

the Texas hornshell is determinable. 

Our regulations at 50 CFR 424.12(a)(2) 

state that critical habitat is not 

determinable when one or both of the 

following situations exist: 

(i) Data sufficient to perform required 

analyses are lacking, or 

(ii) The biological needs of the species 

are not sufficiently well known to 

identify any area that meets the 

definition of ‘‘critical habitat.’’ 

When critical habitat is not 

determinable, the Act allows the Service 

an additional year to publish a critical 

habitat designation (16 U.S.C. 

1533(b)(6)(C)(ii)). 

At the time of our August 10, 2016, 

proposed rule to list the species, we 

found that critical habitat was not 

determinable due to insufficient 

knowledge of the biological needs of the 

species. We have continued to review 

the available information related to the 

Texas hornshell and newly acquired 

information necessary to perform this 

assessment, and we reviewed the 

available information pertaining to the 

biological needs of the species and 

habitat characteristics where this 

species is located. We examined 

collection reports and occupancy 

models for the Texas hornshell 

(Randklev et al. 2017, entire). 

Additionally, we prepared a draft 

economic analysis. This and other 

information represent the best scientific 

data available and led us to conclude 

that the designation of critical habitat is 

determinable for the Texas hornshell. 

Physical or Biological Features 

In accordance with section 3(5)(A)(i) 

of the Act and regulations at 50 CFR 

424.12(b), in determining which areas 

within the geographical area occupied 

by the species at the time of listing to 

designate as critical habitat, we consider 

the physical or biological features that 

are essential to the conservation of the 

species and which may require special 

management considerations or 

protection. The regulations at 50 CFR 

424.02 define ‘‘physical or biological 

features essential to the conservation of 

the species’’ as the features that occur in 

specific areas and that are essential to 

support the life-history needs of the 

species, including but not limited to, 

water characteristics, soil type, 

geological features, sites, prey, 

vegetation, symbiotic species, or other 

features. A feature may be a single 

habitat characteristic, or a more 

complex combination of habitat 

characteristics. Features may include 

habitat characteristics that support 

ephemeral or dynamic habitat 

conditions. Features may also be 

expressed in terms relating to principles 

of conservation biology, such as patch 

size, distribution distances, and 

connectivity. For example, physical 

features might include gravel of a 

particular size required for spawning, 

alkaline soil for seed germination, 

protective cover for migration, or 

susceptibility to flooding or fire that 

maintains necessary early-successional 

habitat characteristics. Biological 

features might include prey species, 

forage grasses, specific kinds or ages of 

trees for roosting or nesting, symbiotic 

fungi, or a particular level of nonnative 

species consistent with conservation 

needs of the listed species. 

The features may also be 

combinations of habitat characteristics 

and may encompass the relationship 

between characteristics or the necessary 

amount of a characteristic needed to 

support the life history of the species. In 

considering whether features are 

essential to the conservation of the 

species, the Service may consider an 

appropriate quality, quantity, and 

spatial and temporal arrangement of 

habitat characteristics in the context of 

the life-history needs, condition, and 

status of the species. These 

characteristics include, but are not 

limited to space for individual and 

population growth and for normal 

behavior; food, water, air, light, 

minerals, or other nutritional or 

physiological requirements; cover or 

shelter; sites for breeding, reproduction, 

or rearing (or development) of offspring; 

and habitats that are protected from 

disturbance. 

Space for Individual and Population 

Growth and for Normal Behavior 

Most freshwater mussels, including 

Texas hornshell, are found in 

aggregations, called mussel beds, that 

vary in size from about 50 to greater 

than 5,000 square meters (m2), separated 

by stream reaches in which mussels are 

absent or rare (Vaughn 2012, p. 983). 

Texas hornshell larvae (called glochidia) 

are parasites that must attach to a host 

fish (generally river carpsucker 

(Carpiodes carpio), grey redhorse 

(Moxostoma congestum), and red shiner 

(Cyprinella lutrensis)). A population of 

Texas hornshell incorporates more than 

one mussel bed; it is the collection of 

mussel beds within a stream reach 

between which infested host fish may 

travel, allowing for ebbs and flows in 

mussel bed density and abundance over 

time throughout the population’s 

occupied reach. Therefore, resilient 


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Texas hornshell populations must 

occupy stream reaches long enough so 

that stochastic events that affect 

individual mussel beds do not eliminate 

the entire population. Repopulation by 

infested host fish from other mussel 

beds within the reach can allow the 

population to recover from these events. 

Longer stream reaches are more likely to 

support populations of Texas hornshell 

into the future than shorter stream 

reaches. Therefore, we determine that 

long stream reaches are an important 

component of a riverine system with 

habitat to support all life stages of Texas 

hornshell. 

Texas hornshell need flowing water 

for survival. They are not found in lakes 

or in pools without flow, or in areas that 

are regularly dewatered. River reaches 

with continuous flow support all life 

stages of Texas hornshell, while those 

with little or no flow do not. Flow rates 

needed by the species will vary 

depending on river size, location, and 

substrate type. 

Additionally, Texas hornshell occur 

in flow refuges such as crevices, 

undercut riverbanks, travertine shelves, 

and large boulders. These refuges must 

have seams of clay or other fine 

sediments within which the mussels 

may anchor, but not so much excess 

sediment that the mussels are 

smothered. Those areas with cleanswept substrate (substrate not covered 

in sediment) with seams of fine 

sediments in crevices are suitable Texas 

hornshell habitat, as well as habitat for 

their host fish. 

Physiological Requirements: Water 

Quality Requirements 

Freshwater mussels, as a group, are 

sensitive to changes in water quality 

parameters such as dissolved oxygen, 

salinity, ammonia, and pollutants. 

Habitats with appropriate levels of these 

parameters are considered suitable, 

while those habitats with levels outside 

of the appropriate ranges are considered 

less suitable. We have used information 

available for other species of freshwater 

mussels to inform the needs of Texas 

hornshell. Juvenile freshwater mussels 

are particularly susceptible to low 

dissolved oxygen levels. Juveniles will 

reduce feeding behavior when dissolved 

oxygen is between 2–4 milligrams per 

liter (mg/L), and mortality has been 

shown to occur at dissolved oxygen 

levels below 1.3 mg/L. Additionally, 

Texas hornshell will die at salinity 

levels of 7 parts per thousand (ppt) for 

more than several weeks (Lang 2001, pp. 

10–11). Juvenile mussels of other 

species have been shown to experience 

complete mortality after 7 days at 

salinity levels greater than 4 ppt 

(Blakeslee et al. 2013, p. 2851) 

The release of pollutants into streams 

from point and nonpoint sources have 

immediate impacts on water quality 

conditions and may make environments 

unsuitable for habitation by mussels. 

Early life stages of freshwater mussels 

are some of the most sensitive 

organisms of all species to ammonia and 

copper (Naimo 1995, pp. 351–352; 

Augsperger et al. 2007, p. 2025). 

Additionally, sublethal effects of 

contaminants over time can result in 

reduced feeding efficiency, reduced 

growth, decreased reproduction, 

changes in enzyme activity, and 

behavioral changes to all mussel life 

stages. Even wastewater discharges with 

low ammonia levels have been shown to 

negatively affect mussel populations. 

Therefore, we determine that stream 

reaches with the following water quality 

parameters are suitable for Texas 

hornshell: 

• Low salinity (less than 0.9 ppt) 

• Low ammonia (less than 0.7 mg/L) 

• Low levels of contaminants 

• Dissolved oxygen levels within 

substrate greater than 1.3 mg/L. 

Sites for Development of Offspring 

As discussed above, Texas hornshell 

larvae are parasites that must attach to 

a host fish to develop into juvenile 

mussels. Texas hornshell primarily use 

river carpsucker, gray redhorse, and red 

shiner as hosts. The river carpsucker 

and red shiner are widespread 

throughout the Texas hornshell’s 

occupied range (Hubbs 1990, pp. 90–91; 

Levine et al. 2012, p. 1857). The 

presence of these fish species, either 

singly or in combination, supports the 

life-history needs of the Texas 

hornshell. 

Summary of Essential Physical or 

Biological Features 

We derive the specific physical or 

biological features essential to the 

conservation of the Texas hornshell 

from studies of this species’ habitat, 

ecology, and life history as described 

below. Additional information can be 

found in the final listing rule published 

in the Federal Register on February 9, 

2018 (83 FR 5720), and the Species 

Status Assessment for the Texas 

Hornshell (Service 2018, entire). We 

have determined that the following 

physical or biological features are 

essential to the conservation of the 

Texas hornshell: 

A riverine system with habitat to 

support all life stages of the Texas 

hornshell, which includes: 

(a) Flowing water at rates high enough 

to support clean-swept substrate but not 

so high as to dislodge individuals; 

(b) Crevices beneath boulders, 

shelves, and within undercut banks 

with seams of fine sediment; 

(c) River carpsucker, red shiner, and 

gray redhorse present; and 

(d) Water quality parameters within 

the following ranges: 

(i) Salinity below 0.9 ppt; 

(ii) Ammonia below 0.7 mg/L; 

(iii) Low levels of contaminants; and 

(iv) Dissolved oxygen levels within 

substrate greater than 1.3mg/L. 

Special Management Considerations or 

Protection 

When designating critical habitat, we 

assess whether the specific areas within 

the geographical area occupied by the 

species at the time of listing contain 

features that are essential to the 

conservation of the species and which 

may require special management 

considerations or protection. The 

features essential to the conservation of 

this species may require special 

management considerations or 

protection to reduce the following 

threats: Increased fine sediment, water 

quality impairment, loss of flowing 

water, and barriers to fish movement. 

Management activities that could 

ameliorate these threats and protect the 

integrity of the stream ecosystem 

include restoring or maintaining the 

natural hydrology of the stream, 

removing livestock from Texas 

hornshell habitats, preventing chemical 

spills, and appropriately maintaining 

bridges and other stream crossings to 

limit sediment input. 

Criteria Used To Identify Critical 

Habitat 

As required by section 4(b)(2) of the 

Act, we use the best scientific data 

available to designate critical habitat. In 

accordance with the Act and our 

implementing regulations at 50 CFR 

424.12(b), we review available 

information pertaining to the habitat 

requirements of the species and identify 

specific areas within the geographical 

area occupied by the species at the time 

of listing and any specific areas outside 

the geographical area occupied by the 

species to be considered for designation 

as critical habitat. We are not currently 

proposing to designate any areas outside 

the geographical area occupied by the 

species at the time of listing in February 

2018. 

The SSA report contains much of the 

information used to identify critical 

habitat for Texas hornshell, which 

includes existing State recovery plans, 

numerous survey reports on streams 


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throughout the species’ range, and 

museum records of historical locations 

(Service 2018). 

Areas Occupied at the Time of Listing 

The proposed critical habitat 

designation does not include all streams 

known to have been occupied by the 

species historically; instead, it focuses 

on occupied streams within the 

historical range that have retained the 

necessary physical and biological 

features (PBFs) that will allow for the 

maintenance and expansion of existing 

populations. The following streams 

meet the definition of areas occupied by 

the species at the time of listing: Black 

River, Delaware River, Pecos River, 

Devils River, and Rio Grande. No 

developed areas occur within the 

proposed designation except for road 

crossings of streams, which do not 

remove the suitability of these areas for 

this species, because habitat is still 

present. 

In summary, for areas proposed as 

critical habitat, we delineated critical 

habitat unit boundaries using the 

following criterion: Evaluate habitat 

suitability of stream segments within 

the geographic area occupied at the time 

of listing, and delineate those segments 

that contain some or all of the PBFs to 

support life-history functions essential 

for conservation of the species. 

As a final step, we evaluated those 

occupied stream segments identified 

through the above analysis and refined 

the starting and ending points by 

evaluating the presence or absence of 

appropriate PBFs. We selected upstream 

and downstream cutoff points to omit 

areas that are highly degraded and are 

not likely to support the Texas 

hornshell. For example, permanently 

dewatered areas or areas in which there 

was a change to unsuitable parameters 

(e.g., water quality, bedrock substrate) 

were used to mark the start or endpoint 

of a stream segment proposed for 

designation. Critical habitat stream 

segments were then mapped using 

ArcMap version 10 (Environmental 

Systems Research Institute, Inc.), a 

Geographic Information Systems 

program. 

The areas proposed for designation as 

critical habitat provide sufficient stream 

habitat for adult Texas hornshell, as 

well as for the habitat needs for 

juveniles and the fish species that serve 

as hosts for the Texas hornshell’s 

parasitic larvae. In general, the PBFs of 

critical habitat are contained within the 

riverine ecosystem formed by the 

channel at bankfull stage. Texas 

hornshell use the riverine ecosystem for 

feeding, breeding, and sheltering. 

When determining proposed critical 

habitat boundaries, we made every 

effort to avoid including developed 

areas such as lands covered by 

buildings, pavement, and other 

structures because such lands lack 

physical or biological features necessary 

for the Texas hornshell. The scale of the 

maps we prepared under the parameters 

for publication within the Code of 

Federal Regulations may not reflect the 

exclusion of such developed lands. Any 

such lands inadvertently left inside 

critical habitat boundaries shown on the 

maps of this proposed rule have been 

excluded by text in the proposed rule 

and are not proposed for designation as 

critical habitat. Therefore, if the critical 

habitat is finalized as proposed, a 

Federal action involving these lands 

would not trigger section 7 consultation 

with respect to critical habitat and the 

requirement of no adverse modification 

unless the specific action would affect 

the physical or biological features in the 

adjacent critical habitat. 

We are proposing for designation of 

critical habitat river miles that we have 

determined were occupied at the time of 

listing and contain one or more of the 

physical or biological features that are 

essential to support life-history 

processes of the species. 

The critical habitat designation is 

defined by the maps, as modified by any 

accompanying regulatory text, presented 

at the end of this document in the rule 

portion. We include more detailed 

information on the boundaries of the 

critical habitat designation in the 

preamble of this document. We will 

make the coordinates or plot points or 

both on which each map is based 

available to the public on http://

www.regulations.gov at Docket No. 

FWS–R2–ES–2017–0030, on our 

internet site (https://www.fws.gov/ 

southwest/es/TexasCoastal/), and at the 

field office responsible for the 

designation (see FOR FURTHER

INFORMATION CONTACT above). 

Proposed Critical Habitat Designation 

We are proposing to designate 463.6 

mi (745.9 km) in five units as critical 

habitat for Texas hornshell. The critical 

habitat areas we describe below 

constitute our current best assessment of 

areas that meet the definition of critical 

habitat for Texas hornshell. The five 

areas we propose as critical habitat are: 

(1) Pecos Tributary Unit; (2) Pecos River 

Unit; (3) Devils River Unit; (4) Rio 

Grande—Lower Canyons Unit; and (5) 

Rio Grande—Laredo Unit. Table 1 

shows the occupancy of the units, the 

land ownership, and approximate areas 

of the proposed designated areas for the 

Texas hornshell. 

TABLE 1—OCCUPANCY, LAND OWNERSHIP, AND SIZE OF TEXAS HORNSHELL PROPOSED CRITICAL HABITAT UNITS AND

SUBUNITS

[BLM = Bureau of Land Management; NGO = non-governmental organization] 

Unit Subunit Occupancy at time of 

listing Current occupancy Riparian ownership Area 

1—Pecos Tributary .... 1a—Black River ........ Occupied ................... Occupied ................... Private ....................... 9.7 mi (15.6 km). 

1b—Delaware River .. Occupied ................... Occupied ................... BLM, Private ............. 31.1 mi (50.0 km). 

2—Pecos River .......... ................................... Occupied ................... Occupied ................... Private, Federal, 

NGO.

85.7 mi (137.9 km). 

3—Devils River ........... ................................... Occupied ................... Occupied ................... Federal, Private, 

NGO, State.

33.0 mi (53.1 km). 

4—Rio Grande— 

Lower Canyons.

4a—Lower Canyons 

Reach.

Occupied ................... Occupied ................... Federal, State ........... 66.7 mi (107.3 km). 

4b—Langtry Reach ... Occupied ................... Occupied ................... Private, Federal ........ 46.5 mi (74.8 km). 

5—Rio Grande—Laredo.5a—Eagle Pass 

Reach.

Occupied ................... Occupied ................... Private, City, Tribal ... 138.7 mi (223.2 km). 

5b—Laredo Reach .... Occupied ................... Occupied ................... Private, City .............. 52.2 mi (84.0 km). 


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We present brief descriptions of all 

units, and reasons why they meet the 

definition of critical habitat for Texas 

hornshell, below. 

Unit 1: Pecos Tributary Unit 

Subunit 1a: Black River: Subunit 1a 

consists of 15.6 km (9.7 mi) in private 

ownership in Eddy County, New 

Mexico. The Texas hornshell occupies 

the entire stream in this subunit, and 

the subunit contains all of the PBFs 

essential to the conservation of Texas 

hornshell. The watershed of the Black 

River is characterized by rural ranching 

and farming, as well as oil and gas 

development. Diverted river water and 

groundwater are used for irrigation of 

farms and ranches as well as hydraulic 

fracturing by oil and gas development 

operations (Bren School of 

Environmental Management 2014, pp. 

32, 130). Additionally, only a few roads 

cross the Black River at low-water 

crossings; therefore, traffic, including 

local and industrial, is concentrated in 

these areas. The relatively short length 

of this reach renders the population 

more susceptible to stochastic events. 

Consequently, special management may 

be necessary to ensure perennial flow in 

the river, prevent contaminant spills, 

and reduce livestock access to the river. 

The Service has collaborated with 

water users, oil and gas developers, 

landowners, and other partners to 

develop a Candidate Conservation 

Agreement (CCA) and Candidate 

Conservation Agreements with 

Assurances (CCAAs) for the species on 

State, Federal, and private lands. The 

purpose of these agreements is to 

provide voluntary conservation that 

would reduce threats to the species 

while improving physical habitat and 

water quality. The key conservation 

measures in the agreements are 

designed to limit oil and gas 

development to areas outside of the 

Black and Delaware River floodplains, 

minimize erosion, and maintain 

minimum water flows in the rivers. 

Along with these measures, the partners 

to the agreement are evaluating 

alternatives to the multiple low water 

crossings on the Black River. Partners 

are considering alternate crossing 

locations that could include bridges 

designed to allow host fishes to pass 

through in addition to decreasing 

potential contamination events. We are 

considering excluding the subunit 

under section 4(b)(2) of the Act if these 

agreements are implemented in a 

manner sufficient to defray the need for 

additional special management. 

Subunit 1b: Delaware River: Subunit 

1b consists of 50.0 km (31.1 mi) of 

occupied habitat in the Delaware River 

in Culberson County, Texas, and Eddy 

County, New Mexico. Texas hornshell 

were historically known from dead 

shells found within this subunit; the 

species was likely extirpated due to lack 

of water. Habitat improvements 

undertaken by the Bureau of Land 

Management (BLM) resulted in 

perennial flow through the rehabilitated 

section of the Delaware River (BLM 

2005, p. 1). A total of 126 adult Texas 

hornshell were reintroduced to the river 

in New Mexico in 2014 and 2015. The 

reintroduced adults were recaptured 

alive and the females were gravid 

(brooding larvae) in 2016, indicating 

preliminary success. A spill of 11 

barrels of oil and 18,000 barrels of water 

that has been collected as a byproduct 

of oil and gas production occurred 

upstream of the reintroduced 

individuals in August 2017; the effects 

of this spill and the subsequent flooding 

has resulted in only two of the 

reintroduced individuals still remaining 

in the Delaware River. The New Mexico 

Department of Game and Fish plan to 

continue their reintroduction efforts to 

ensure a diverse, reproducing 

population persists in the river; 

successful freshwater mussel 

reintroductions typically require 

multiple years of effort. Riparian 

ownership consists of the BLM and 

private landowners. The BLM helped 

restore perennial flow to the river 

through riparian management, and now 

the reach contains all of the PBFs 

essential to the conservation of Texas 

hornshell. 

The Delaware River is included in the 

CCA/CCAA described in Subunit 1a; 

therefore, we are considering it for 

exclusion under section 4(b)(2) of the 

Act. 

Unit 2: Pecos River Unit 

This unit consists of 137.9 km (85.7 

mi) in private, non-governmental 

organization (NGO), and Federal 

ownership of the Pecos River in Val 

Verde and Terrell Counties, Texas. This 

unit is occupied. Three live Texas 

hornshell were collected from the Pecos 

River Unit in 2016, which, based on 

species survey efforts, indicates several 

other living Texas hornshell were likely 

in the unit at that time. In addition, the 

2016 collection resulted in numerous 

shells of the Texas hornshell (Bosman et 

al. 2016, p. 6; Randklev et al. 2016, p. 

9), which is further evidence that 

additional members of the species were 

in the Pecos River. The live specimens 

collected in 2016 were very old, but we 

have no indication that they were no 

longer occupying the Pecos River at the 

time of listing. The direct evidence of 

multiple living specimens of Texas 

hornshell in the Pecos River as recently 

as 2016, along with the conclusion that 

other members of the species were 

likely present at that time, allows us to 

conclude that the Pecos River Unit was 

occupied at the time of listing. This unit 

contains some of the PBFs essential to 

the conservation of Texas hornshell, 

such as flowing water and adequate 

crevices, but salinity is relatively high 

in this unit, compromising water 

quality. Special management may be 

necessary to improve water quality in 

this reach. 

Unit 3: Devils River Unit 

This unit consists of 53.1 km (33.0 mi) 

of the Devils River in Val Verde County, 

Texas. Riparian lands are primarily in 

private ownership, including The 

Nature Conservancy (TNC), and both the 

Texas Parks and Wildlife Department 

(TPWD) and the Federal Government 

owns portions of these lands. Texas 

hornshell are historically known from 

the Devils River and currently occupy 

the unit. The Devils River represents a 

relatively intact watershed, with no 

dams, little development, and much of 

it under conservation management. 

Texas hornshell sites are located on 

Dolan Falls Preserve, which is 4,800 

acres (ac) (1,943 hectares (ha)) owned by 

TNC, as well as an additional 13,722 ac 

(5,553 ha) managed under a 

conservation easement. TNC also owns 

Nix 2 Ranch (87,000 ac (35,209 ha)), and 

TPWD owns the Devils River State 

Natural Area (37,000 ac (15,000 ha)), 

resulting in conservation management 

of much of the land along the river (TNC 

2004, p. 9; TPWD 2016, p. 1). The PBFs 

essential to the conservation of Texas 

hornshell are present in the Devils 

River. Special management may be 

necessary to maintain instream flows in 

the river. 

Unit 4: Rio Grande—Lower Canyons 

Subunit 4a: Lower Canyons Reach: 

This subunit consists of 107.3 km (66.7 

mi) of occupied habitat on the U.S. side 

of the Rio Grande in Terrell and 

Brewster Counties, Texas. Most of this 

reach is part of the Rio Grande Wild and 

Scenic River, owned by the United 

States and managed by the National 

Park Service. A small portion of the 

subunit is owned by the State of Texas. 

The PBFs essential to the conservation 

of Texas hornshell are present in this 

subunit. It was designated a National 

Wild and Scenic River in 1978 (Garrett 

and Edwards 2004, p. 396), which 

affords some protection from Federal 

development projects, but does not limit 

State, local, or private development 

(National Wild and Scenic Rivers 

System 2016, p. 1). Special management 


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may be necessary to maintain instream 

flows in the river. 

Subunit 4b: Langtry Reach: This 

subunit consists of 74.8 km (46.5 mi) of 

the U.S. side of the Rio Grande in 

Terrell and Val Verde Counties, Texas, 

most of which is also owned and 

managed by the National Park Service. 

A small portion of this subunit is in 

private ownership. This unit contains 

all of the PBFs and is connected to the 

known population of Texas hornshell in 

Subunit 4a, but the remote nature of this 

reach has prevented surveys. There are 

no instream structures in Subunit 4b 

that would impede water flow; the flow 

regime is the same as in Subunit 4a; and 

the host fish may move between the 

subunits freely. Based on this 

information, it is reasonable to conclude 

that that the population in Subunit 4a 

is unlikely to stop at the most 

downstream survey location; therefore, 

we conclude this subunit is occupied. 

However, due to the lack of recent 

surveys, we are analyzing this subunit 

against the second prong of the 

definition of critical habitat for 

unoccupied habitat out of an abundance 

of caution. If Subunit 4b is not, in fact, 

occupied, it would provide for needed 

growth and expansion of the species in 

this portion of its historical range. The 

longer the occupied reach, the more 

likely it is that the Texas hornshell 

population can withstand stochastic 

events such as extreme flooding, 

dewatering, or water contamination. 

Therefore, Subunit 4b is essential for the 

conservation of the species. 

Like Subunit 4a, this subunit is part 

of the Rio Grande Wild and Scenic 

River, which affords some protection 

from Federal development projects, but 

does not limit State, local, or private 

development (National Wild and Scenic 

Rivers System 2016, p. 1). Special 

management may be necessary to 

maintain instream flows in the river. 

Unit 5: Rio Grande—Laredo 

Subunit 5a: Eagle Pass Reach: This 

subunit consists of 223.2 km (138.7 mi) 

of the U.S. side of the Rio Grande from 

Del Rio, Texas, to upstream of the 

Laredo population of Texas hornshell in 

Kinney and Maverick Counties, Texas. 

This subunit is primarily privately 

owned, with small portions owned by 

the City of Eagle Pass and the Kickapoo 

Tribe of Texas. We conclude that this 

reach was occupied at the time of 

listing. This conclusion is based on the 

collection of two live individuals near 

Del Rio between 2008 and 2011 

(Karatayev et al. 2015, p. 8). The 

immobility of Texas hornshell and the 

continued presence of suitable habitat 

indicates the species remained in the 

area at the time of listing. This reach 

includes all of the PBFs necessary to 

support the continued existence of the 

species. Additionally, the hydrological 

connection with Subunit 5b, which 

contains the largest known population 

of Texas hornshell, allows for host fish 

movement between the subunits. 

However, due to the lack of recent 

records, we are analyzing this subunit 

against the second prong of the 

definition of critical habitat for 

unoccupied habitat out of an abundance 

of caution. If Subunit 5a is not 

occupied, it would provide for needed 

growth and expansion of the species in 

this portion of its historical range. The 

longer the occupied reach, the more 

likely it is that the Texas hornshell 

population can withstand stochastic 

events such as extreme flooding, 

dewatering, or water contamination. 

Therefore, Subunit 5a is essential for the 

conservation of the species. 

The Rio Grande in this subunit is 

heavily influenced by development 

along the Texas-Mexico border, and the 

river has a high sediment load in this 

reach (Texas Clean Rivers Program 

2013, p. 9). Flows are regulated by 

releases from Amistad Reservoir based 

on hydropower generation and water 

deliveries for downstream irrigation 

needs (Texas Water Development Board 

2016, p. 1). Special management may be 

necessary to improve water quality and 

reduce sedimentation. 

Subunit 5b: Laredo Reach: This 

subunit consists of 84.0 km (52.2 mi) of 

the U.S. side of the Rio Grande 

upstream of Laredo in Webb County, 

Texas, in private and city ownership. 

This subunit is occupied and contains 

the largest known Texas hornshell 

population (Randklev et al. 2015, p. 7). 

Like subunit 5a, this subunit is heavily 

influenced by development along the 

Texas-Mexico border, and rapid human 

population growth as well as 

industrialization on the Mexican side of 

the river has stressed the existing 

wastewater treatment facilities, and Rio 

Grande water quality is impaired as a 

result (Texas Clean Rivers Program 

2013, p. 7). All of the PBFs essential to 

the conservation of Texas hornshell are 

found in this reach, although special 

management to improve water quality 

may be necessary. 

Effects of Critical Habitat Designation 

Section 7 Consultation 

Section 7(a)(2) of the Act requires 

Federal agencies, including the Service, 

to ensure that any action they fund, 

authorize, or carry out is not likely to 

jeopardize the continued existence of 

any endangered species or threatened 

species or result in the destruction or 

adverse modification of designated 

critical habitat of such species. In 

addition, section 7(a)(4) of the Act 

requires Federal agencies to confer with 

the Service on any agency action that 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 

proposed critical habitat. 

We published a final regulation with 

a revised definition of destruction or 

adverse modification on August 27, 

2019 (84 FR 44976). Destruction or 

adverse modification means a direct or 

indirect alteration that appreciably 

diminishes the value of critical habitat 

as a whole for the conservation of a 

listed species. 

If a Federal action may affect a listed 

species or its critical habitat, the 

responsible Federal agency (action 

agency) must enter into consultation 

with us. Examples of actions that are 

subject to the section 7 consultation 

process are 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. 

As a result of section 7 consultation, 

we document compliance with the 

requirements of section 7(a)(2) through 

our issuance of: 

(1) A concurrence letter for Federal 

actions that may affect, but are not 

likely to adversely affect, listed species 

or critical habitat; or 

(2) A biological opinion for Federal 

actions that may affect and are likely to 

adversely affect, listed species or critical 

habitat. 

When we issue a biological opinion 

concluding that a project is likely to 

jeopardize the continued existence of a 

listed species and/or destroy or 

adversely modify critical habitat, we 

provide reasonable and prudent 

alternatives to the project, if any are 

identifiable, that would avoid the 

likelihood of jeopardy and/or 

destruction or adverse modification of 

critical habitat. We define ‘‘reasonable 

and prudent alternatives’’ (at 50 CFR 


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402.02) as alternative actions identified 

during consultation that: 

(1) Can be implemented in a manner 

consistent with the intended purpose of 

the action, 

(2) Can be implemented consistent 

with the scope of the Federal agency’s 

legal authority and jurisdiction, 

(3) Are economically and 

technologically feasible, and 

(4) Would, in the Director’s opinion, 

avoid the likelihood of jeopardizing the 

continued existence of the listed species 

and/or avoid the likelihood of 

destroying or adversely modifying 

critical habitat. 

Reasonable and prudent alternatives 

can vary from slight project 

modifications to extensive redesign or 

relocation of the project. Costs 

associated with implementing a 

reasonable and prudent alternative are 

similarly variable. 

Regulations at 50 CFR 402.16 require 

Federal agencies to reinitiate formal 

consultation on previously reviewed 

actions. These requirements apply when 

the Federal agency has retained 

discretionary involvement or control 

over the action (or the agency’s 

discretionary involvement or control is 

authorized by law) and, subsequent to 

the previous consultation, we have 

listed a new species or designated 

critical habitat that may be affected by 

the Federal action, or the action has 

been modified in a manner that affects 

the species or critical habitat in a way 

not considered in the previous 

consultation. In such situations, Federal 

agencies sometimes may need to request 

reinitiation of consultation with us, but 

the regulations also specify some 

exceptions to the requirement to 

reinitiate consultation on specific land 

management plans after subsequently 

listing a new species or designating new 

critical habitat. See the regulations for a 

description of those exceptions. 

Application of the ‘‘Adverse 

Modification’’ Standard 

The key factor related to the 

destruction or adverse modification 

determination is whether 

implementation of the proposed Federal 

action directly or indirectly alters the 

designated critical habitat in a way that 

appreciably diminishes the value of the 

critical habitat as a whole for the 

conservation of the listed species. As 

discussed above, the role of critical 

habitat is to support physical or 

biological features essential to the 

conservation of a listed species and 

provide for the conservation of the 

species. Section 4(b)(8) of the Act 

requires us to briefly evaluate and 

describe, in any proposed or final 

regulation that designates critical 

habitat, activities involving a Federal 

action that may violate 7(a)(2) of the Act 

by destroying or adversely modifying 

such designation. 

Activities that the Services may, 

during a consultation under section 

7(a)(2) of the Act, find are likely to 

destroy or adversely modify critical 

habitat include, but are not limited to: 

(1) Actions that would alter the 

existing flow regime. Such activities 

could include, but are not limited to, 

impoundment, water diversion, and 

water withdrawal. These activities 

could eliminate or reduce the habitat 

necessary for the growth and 

reproduction of these mussels. 

(2) Actions that would significantly 

alter water chemistry or temperature. 

Such activities could include, but are 

not limited to, release of chemicals, 

biological pollutants, or heated effluents 

into the surface water or connected 

groundwater at a point source or by 

dispersed release (non-point source). 

These activities could alter water 

conditions to levels that are beyond the 

tolerances of the mussels or their fish 

host and result in direct or cumulative 

adverse effects to these individuals and 

their life cycles. 

(3) Actions that would significantly 

increase sediment deposition within the 

stream channel. Such activities could 

include, but are not limited to, excessive 

sedimentation from livestock grazing, 

road construction, channel alteration, 

and other watershed and floodplain 

disturbances. These activities could 

eliminate or reduce the habitat 

necessary for the growth and 

reproduction of these mussels and their 

fish host by increasing the sediment 

deposition to levels that would 

adversely affect their ability to complete 

their life cycles. 

Exemptions 

Application of Section 4(a)(3) of the Act 

Section 4(a)(3)(B)(i) of the Act (16 

U.S.C. 1533(a)(3)(B)(i)) provides that: 

‘‘The Secretary shall not designate as 

critical habitat any lands or other 

geographic areas owned or controlled by 

the Department of Defense, or 

designated for its use, that are subject to 

an integrated natural resources 

management plan (INRMP) prepared 

under section 101 of the Sikes Act (16 

U.S.C. 670a), if the Secretary determines 

in writing that such plan provides a 

benefit to the species for which critical 

habitat is proposed for designation.’’ 

There are no Department of Defense 

lands within the proposed critical 

habitat designation. 

Consideration of Impacts Under Section 

4(b)(2) of the Act 

Section 4(b)(2) of the Act states that 

the Secretary shall designate and make 

revisions to critical habitat on the basis 

of the best available scientific data after 

taking into consideration the economic 

impact, national security impact, and 

any other relevant impact of specifying 

any particular area as critical habitat. 

The Secretary may exclude an area from 

critical habitat if he determines that the 

benefits of such exclusion outweigh the 

benefits of specifying such area as part 

of the critical habitat, unless he 

determines, based on the best scientific 

data available, that the failure to 

designate such area as critical habitat 

will result in the extinction of the 

species. In making that determination, 

the statute on its face, as well as the 

legislative history, are clear that the 

Secretary has broad discretion regarding 

which factor(s) to use and how much 

weight to give to any factor. 

When identifying the benefits of 

inclusion for an area, we consider the 

additional regulatory benefits that area 

would receive due to the protection 

from destruction of adverse 

modification as a result of actions with 

a Federal nexus; the educational 

benefits of mapping essential habitat for 

recovery of the listed species; and any 

benefits that may result from a 

designation due to State or Federal laws 

that may apply to critical habitat. In the 

case of the Texas hornshell, the benefits 

of critical habitat include public 

awareness of the presence of the Texas 

hornshell and the importance of habitat 

protection, and, where a Federal nexus 

exists, increased habitat protection for 

the Texas hornshell due to protection 

from destruction or adverse 

modification of critical habitat. 

When considering the benefits of 

exclusion, we consider, among other 

things, whether exclusion of a specific 

area is likely to result in conservation or 

the continuation, strengthening, or 

encouragement of partnerships. 

Continued implementation of an 

ongoing management plan that provides 

equal to or more conservation than a 

critical habitat designation would 

reduce the benefits of including that 

specific area in the critical habitat 

designation. 

We evaluate the existence of a 

conservation plan when considering the 

benefits of inclusion. We consider a 

variety of factors, including but not 

limited to, whether the plan is finalized; 

how it provides for the conservation of 

the essential physical or biological 

features; whether there is a reasonable 

expectation that the conservation 


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management strategies and actions 

contained in a management plan will be 

implemented into the future; whether 

the conservation strategies in the plan 

are likely to be effective; and whether 

the plan contains a monitoring program 

or adaptive management to ensure that 

the conservation measures are effective 

and can be adapted in the future in 

response to new information. 

After identifying the benefits of 

inclusion and the benefits of exclusion, 

we carefully weigh the two sides to 

evaluate whether the benefits of 

exclusion outweigh those of inclusion. 

If our analysis indicates that the benefits 

of exclusion outweigh the benefits of 

inclusion, we then determine whether 

exclusion would result in extinction of 

the species. If exclusion of an area from 

critical habitat will result in extinction, 

we will not exclude it from the 

designation. 

The final decision on whether to 

exclude any areas will be based on the 

best scientific data available at the time 

of the final designation, including 

information obtained during the 

comment period and information about 

the economic impact of designation. 

Accordingly, we have prepared a draft 

economic analysis concerning the 

proposed critical habitat designation, 

which is available for review and 

comment (see ADDRESSES). 

Consideration of Economic Impacts 

Section 4(b)(2) of the Act and its 

implementing regulations require that 

we consider the economic impact that 

may result from a designation of critical 

habitat. To assess the probable 

economic impacts of a designation, we 

must first evaluate specific land uses or 

activities and projects that may occur in 

the area of the critical habitat. We then 

must evaluate the impacts that a specific 

critical habitat designation may have on 

restricting or modifying specific land 

uses or activities for the benefit of the 

species and its habitat within the areas 

proposed. We then identify which 

conservation efforts may be the result of 

the species being listed under the Act 

versus those attributed solely to the 

designation of critical habitat for this 

particular species. 

The probable economic impact of a 

proposed critical habitat designation is 

analyzed by comparing scenarios both 

‘‘with critical habitat’’ and ‘‘without 

critical habitat.’’ The ‘‘without critical 

habitat’’ scenario represents the baseline 

for the analysis, which includes the 

existing regulatory and socio-economic 

burden imposed on landowners, 

managers, or other resource users 

potentially affected by the designation 

of critical habitat (e.g., under the 

Federal listing as well as other Federal, 

State, and local regulations). The 

baseline, therefore, represents the costs 

of all efforts attributable to the listing of 

the species under the Act (i.e., 

conservation of the species and its 

habitat incurred regardless of whether 

critical habitat is designated). The ‘‘with 

critical habitat’’ scenario describes the 

incremental impacts associated 

specifically with the designation of 

critical habitat for the species. The 

incremental conservation efforts and 

associated impacts would not be 

expected without the designation of 

critical habitat for the species. In other 

words, the incremental costs are those 

attributable solely to the designation of 

critical habitat, above and beyond the 

baseline costs. These are the costs we 

use when evaluating the benefits of 

inclusion and exclusion of particular 

areas from the final designation of 

critical habitat should we choose to 

conduct a discretionary section 4(b)(2) 

exclusion analysis. 

For this particular designation, we 

developed an Incremental Effects 

Memorandum (IEM) considering the 

probable incremental economic impacts 

that may result from this proposed 

designation of critical habitat. The 

information contained in our IEM was 

then used to develop a screening 

analysis of the probable effects of the 

designation of critical habitat for the 

Texas hornshell (Industrial Economics, 

Inc. 2019). 

We began by conducting a screening 

analysis of the proposed designation of 

critical habitat in order to focus our 

analysis on the key factors that are 

likely to result in incremental economic 

impacts. The purpose of the screening 

analysis is to filter out the geographic 

areas in which the critical habitat 

designation is unlikely to result in 

probable incremental economic impacts. 

In particular, the screening analysis 

considers baseline costs (i.e., absent 

critical habitat designation) and 

includes probable economic impacts 

where land and water use may be 

subject to conservation plans, land 

management plans, best management 

practices, or regulations that protect the 

habitat area as a result of the Federal 

listing status of the species. The 

screening analysis filters out particular 

areas of critical habitat that are already 

subject to such protections and are, 

therefore, unlikely to incur incremental 

economic impacts. Ultimately, the 

screening analysis allows us to focus 

our analysis on evaluating the specific 

areas or sectors that may incur probable 

incremental economic impacts as a 

result of the designation. The screening 

analysis also assesses whether units that 

are unoccupied by the species may 

require additional management or 

conservation efforts as a result of the 

critical habitat designation, thereby 

possibly incurring incremental 

economic impacts. This screening 

analysis combined with the information 

contained in our IEM are what we 

consider our draft economic analysis of 

the proposed critical habitat designation 

for the Texas hornshell, and this 

analysis is summarized in the narrative 

below. 

Executive Orders 12866 and 13563 

direct Federal agencies to assess the 

costs and benefits of available regulatory 

alternatives in quantitative (to the extent 

feasible) and qualitative terms. 

Consistent with the E.O. regulatory 

analysis requirements, our effects 

analysis under the Act may take into 

consideration impacts to both directly 

and indirectly affected entities, where 

practicable and reasonable. If sufficient 

data are available, we assess to the 

extent practicable the probable impacts 

to both directly and indirectly affected 

entities. As part of our screening 

analysis, we considered the types of 

economic activities that are likely to 

occur within the areas likely affected by 

the critical habitat designation. 

In our evaluation of the probable 

incremental economic impacts that may 

result from the proposed designation of 

critical habitat for the Texas hornshell, 

first we identified, in the IEM dated 

December 5, 2016, probable incremental 

economic impacts associated with the 

following categories of activities: (1) 

Federal lands management (National 

Park Service, Bureau of Land 

Management); (2) roadway and bridge 

construction; (3) agriculture; (4) grazing; 

(5) groundwater pumping; (6) in-stream 

dams and diversions; (7) oil and gas 

production; and (8) border protection. 

We considered each industry or 

category individually. Additionally, we 

considered whether their activities have 

any Federal involvement. Critical 

habitat designation generally will not 

affect activities that do not have any 

Federal involvement; under the ESA, 

designation of critical habitat affects 

only activities conducted, funded, 

permitted, or authorized by Federal 

agencies. In areas where the Texas 

hornshell is present, Federal agencies 

already are required to consult with the 

Service under section 7 of the Act on 

activities they fund, permit, or 

implement that may affect the species. 

If we finalize this proposed critical 

habitat designation, consultations to 

avoid the destruction or adverse 

modification of critical habitat would be 

incorporated into the existing 

consultation process. 


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In our IEM, we attempted to clarify 

the distinction between the effects that 

will result from the species being listed 

and those attributable to the critical 

habitat designation (i.e., difference 

between the jeopardy and adverse 

modification standards) for the Texas 

hornshell’s critical habitat. The Texas 

hornshell has not been listed long 

enough for us to have conducted any 

section 7 consultations. It has been our 

experience that, for such species, it is 

more difficult to discern which 

conservation efforts are attributable to 

the species being listed and which will 

result solely from the designation of 

critical habitat. However, the following 

specific circumstances in this case help 

to inform our evaluation: (1) The 

essential physical or biological features 

identified for critical habitat are the 

same features essential for the life 

requisites of the species and (2) any 

actions that would result in sufficient 

harm or harassment to constitute 

jeopardy to the Texas hornshell would 

also likely adversely affect the essential 

physical or biological features of critical 

habitat. The IEM outlines our rationale 

concerning this limited distinction 

between baseline conservation efforts 

and incremental impacts of the 

designation of critical habitat for this 

species. This evaluation of the 

incremental effects has been used as the 

basis to evaluate the probable 

incremental economic impacts of this 

proposed designation of critical habitat. 

The proposed critical habitat 

designation for the Texas hornshell 

totals 463.6 mi (745.9 km) in five units, 

all of which were occupied at the time 

of listing. However, two subunits—4b 

and 5a (comprising 40 percent of the 

proposed critical habitat designation)— 

have few records of Texas hornshell and 

are so remote that we do not believe 

listing the species made the public 

aware of its presence in these areas. As 

a result, we do not expect section 7 

consultations to be initiated in these 

areas until additional awareness is 

brought to these areas when they are 

designated as critical habitat. Therefore, 

while all units of the proposed critical 

habitat were occupied at the time of 

listing, we conducted an economic 

analysis that modeled Subunits 4b and 

5a as unoccupied so that we could more 

accurately represent the anticipated 

increase in public awareness and cost of 

project modifications when these areas 

are designated as critical habitat. As a 

result, our economic effects analysis 

demonstrates the maximum economic 

effects of the critical habitat designation. 

All other subunits (besides the two 

modeled as unoccupied) comprise 60 

percent of the designation and were 

modeled as occupied in the economic 

analysis. In these areas, any actions that 

may affect the species or its habitat 

would also affect designated critical 

habitat and it is unlikely that any 

additional conservation efforts would be 

recommended to address the adverse 

modification standard over and above 

those recommended as necessary to 

avoid jeopardizing the continued 

existence of the Texas hornshell. 

Therefore, only administrative costs are 

expected in approximately 60 percent of 

the proposed critical habitat 

designation. While this additional 

analysis will require time and resources 

by both the Federal action agency and 

the Service, we believe that in most 

circumstances these costs would 

predominantly be administrative in 

nature and would not exceed $89,000 in 

a single year. 

The remaining subunits (185.2 mi 

(298.0) km, or 40 percent of the total 

proposed critical habitat designation) 

that were analyzed as unoccupied by 

the species for the purposes of the 

economic analysis are essential for the 

conservation of the species. In these 

areas, any conservation efforts or 

associated probable impacts would be 

considered incremental effects 

attributed to the critical habitat 

designation. Subunit 4b (Rio Grande– 

Lower Canyons, Langtry Reach) is very 

remote with little to no development, 

and activities that could affect the Texas 

hornshell or its habitat are not expected 

to occur in these areas. We do not 

anticipate any projects because of how 

remote Subunit 4b is, as well as the lack 

of historical, current, or planned 

activities in this area. Subunit 5a (Rio 

Grande–Laredo, Eagle Pass Reach) has 

potential for projects to occur; however, 

because this reach is upstream of 

occupied habitat, for large projects, 

project modifications requested to avoid 

adverse modification are likely to be the 

same as those that would be needed to 

avoid jeopardizing the species in 

downstream, occupied critical habitat. 

For small projects that may affect 

critical habitat in this reach, project 

modifications would be the same as 

conservation measures currently 

included in best management practices 

under Clean Water Act section 404 

permits issued by the U.S. Army Corps 

of Engineers. Therefore, costs are 

unlikely to exceed $100 million in any 

single year and would not be significant, 

based on the definition of significance 

in E.O. 12866. 

The entities most likely to incur 

incremental costs are parties to section 

7 consultations, including Federal 

action agencies and, in some cases, third 

parties, most frequently State agencies 

or municipalities. Activities we expect 

will be subject to consultations that may 

involve private entities as third parties 

are residential and commercial 

development that may occur on private 

lands. However, based on coordination 

efforts with State and local agencies, the 

cost to private entities within these 

sectors is expected to be relatively 

minor (administrative costs of less than 

$10,000 per consultation effort) and 

would not be significant (exceed $100 

million in a single year). 

The probable incremental economic 

impacts of the Texas hornshell critical 

habitat designation are expected to be 

limited to additional administrative 

effort as well as minor costs of 

conservation efforts resulting from a 

small number of future section 7 

consultations. This is due to two factors: 

(1) In proposed critical habitat stream 

reaches that were analyzed as occupied 

by the species (60 percent), incremental 

economic impacts of critical habitat 

designation, other than administrative 

costs, are unlikely; and (2) in proposed 

areas that were analyzed as if they were 

unoccupied by the Texas hornshell (40 

percent), few actions are anticipated 

that will result in section 7 consultation 

or associated project modifications. At 

approximately $10,000 or less per 

consultation, in order to reach the 

threshold of $100 million of incremental 

administrative impacts in a single year, 

critical habitat designation would have 

to result in more than 11,000 

consultations in a single year. Thus, the 

annual administrative burden is 

unlikely to reach $100 million. 

As we stated earlier, we are soliciting 

data and comments from the public on 

the draft economic analysis, as well as 

all aspects of the proposed rule and our 

amended required determinations. We 

may revise the proposed rule or 

supporting documents to incorporate or 

address information we receive during 

the public comment period. In 

particular, we may exclude an area from 

critical habitat if we determine that the 

benefits of excluding the area outweigh 

the benefits of including the area, 

provided the exclusion will not result in 

the extinction of this species. 

Exclusions 

Based on the information provided by 

entities seeking exclusion, as well as 

any additional public comments 

received, we will evaluate whether 

certain lands are appropriate for 

exclusion from the final designation 

under section 4(b)(2) of the Act. If the 

analysis indicates that the benefits of 

excluding lands from the final 

designation outweigh the benefits of 

designating those lands as critical 


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habitat, then the Secretary may exercise 

his discretion to exclude the lands from 

the final designation. 

We are considering whether to 

exclude Unit 1: Pecos Tributary Unit 

under section 4(b)(2) of the Act from the 

final critical habitat designation for the 

Texas hornshell because of the 

conservation agreements discussed 

earlier in this document. The Service 

has collaborated with water users, oil 

and gas developers, landowners, and 

other partners to implement a CCA and 

CCAA for the Texas hornshell on State, 

Federal, and private lands in the Black 

and Delaware River watersheds. The key 

conservation measures in the 

agreements are designed to limit oil and 

gas development to areas outside of the 

Black and Delaware River floodplains, 

minimize erosion in order to maintain 

suitable substrate, and maintain 

minimum water flows in the rivers. 

Along with these measures, the partners 

to the agreement are evaluating 

alternatives to the multiple low water 

crossings on the Black River to reduce 

the potential for river contamination. 

Partners are considering alternate 

crossing locations that could include 

bridges designed to allow host fishes to 

pass through in addition to decreasing 

the risk of contamination events. 

The Pecos Tributary Unit consists of 

two subunits, the Black River Subunit 

(9.7 mi (15.6 km)) and the Delaware 

River Subunit (31.1 mi (50.0 km)). A 

CCA and CCAA between the Service, 

BLM, New Mexico State Land Office, 

and Center of Excellence has been 

completed for the Black and Delaware 

Rivers in New Mexico and Texas. We 

are considering the exclusion of nonFederal lands covered by this plan that 

provide for the conservation of the 

Texas hornshell. We are requesting 

comments on the benefit to the Texas 

hornshell from the CCA/CCAA; 

however, at this time, we are not 

proposing to exclude any area within 

the proposed critical habitat for the 

Texas hornshell. 

However, we specifically solicit 

comments on the inclusion or exclusion 

of the Pecos Tributary Unit. 

Any other plans in development that 

are submitted to us will be evaluated 

and could result in the exclusion of 

additional proposed critical habitat 

units from the final designation. 

Exclusions Based on Economic Impacts 

Under section 4(b)(2) of the Act, we 

consider the economic impacts of 

specifying any particular area as critical 

habitat. In order to consider economic 

impacts, we prepared an analysis of the 

economic impacts of the proposed 

critical habitat designation and related 

factors. Potential land use sectors that 

may be affected by the Texas hornshell 

critical habitat designation include 

water diversion, impoundment repairs, 

bridge and highway maintenance, oil 

and gas development, border protection, 

grazing, groundwater withdrawals, and 

agriculture. 

During the development of a final 

designation, we will consider any 

additional economic impact information 

received through the public comment 

period, and as such areas may be 

excluded from the final critical habitat 

designation under section 4(b)(2) of the 

Act and our implementing regulations at 

50 CFR 424.19. 

Impacts on National Security and 

Homeland Security 

Section 4(a)(3)(B)(i) of the Act may 

not cover all Department of Defense 

(DoD) lands or areas that pose potential 

national-security concerns (e.g., a DoD 

installation that is in the process of 

revising its INRMP for a newly listed 

species or a species previously not 

covered). If a particular area is not 

covered under section 4(a)(3)(B)(i), 

national-security or homeland-security 

concerns are not a factor in the process 

of determining what areas meet the 

definition of ‘‘critical habitat.’’ 

Nevertheless, when designating critical 

habitat under section 4(b)(2), the Service 

must consider impacts on national 

security, including homeland security, 

on lands or areas not covered by section 

4(a)(3)(B)(i). Accordingly, we will 

always consider for exclusion from the 

designation areas for which DoD, 

Department of Homeland Security 

(DHS), or another Federal agency has 

requested exclusion based on an 

assertion of national-security or 

homeland-security concerns. 

We cannot, however, automatically 

exclude requested areas. When DoD, 

DHS, or another Federal agency requests 

exclusion from critical habitat on the 

basis of national-security or homelandsecurity impacts, it must provide a 

reasonably specific justification of an 

incremental impact on national security 

that would result from the designation 

of that specific area as critical habitat. 

That justification could include 

demonstration of probable impacts, 

such as impacts to ongoing bordersecurity patrols and surveillance 

activities, or a delay in training or 

facility construction, as a result of 

compliance with section 7(a)(2) of the 

Act. If the agency requesting the 

exclusion does not provide us with a 

reasonably specific justification, we will 

contact the agency to recommend that it 

provide a specific justification or 

clarification of its concerns relative to 

the probable incremental impact that 

could result from the designation. If the 

agency provides a reasonably specific 

justification, we will defer to the expert 

judgment of DoD, DHS, or another 

Federal agency as to: (1) Whether 

activities on its lands or waters, or its 

activities on other lands or waters, have 

national-security or homeland-security 

implications; (2) the importance of those 

implications; and (3) the degree to 

which the cited implications would be 

adversely affected in the absence of an 

exclusion. In that circumstance, in 

conducting a discretionary section 

4(b)(2) exclusion analysis, we will give 

great weight to national-security and 

homeland-security concerns in 

analyzing the benefits of exclusion. 

We are not considering or proposing 

any lands for exclusions based on 

national security impacts under section 

4(b)(2) of the Act in this proposed 

critical habitat rule. We have 

coordinated with the DHS and will 

continue to do so during the 

development of the final rule. U.S. 

Customs and Border Protection 

indicated that construction and 

maintenance of boat ramps, sediment 

removal, and dam construction may be 

affected by the designation of critical 

habitat for the Texas hornshell. We note 

that Congress has provided to the 

Secretary of Homeland Security a 

number of authorities necessary to carry 

out the Department’s border security 

mission. One of those authorities is 

found at section 102 of the Illegal 

Immigration Reform and Immigrant 

Responsibility Act of 1996, as amended 

(‘‘IIRIRA’’). In section 102(a) of IIRIRA, 

Congress provided that the Secretary of 

Homeland Security shall take such 

actions as may be necessary to install 

additional physical barriers and roads 

(including the removal of obstacles to 

detection of illegal entrants) in the 

vicinity of the United States border to 

deter illegal crossings in areas of high 

illegal entry into the United States. In 

section 102(b) of IIRIRA, Congress 

mandated the installation of additional 

fencing, barriers, roads, lighting, 

cameras, and sensors on the southwest 

border. Finally, in section 102(c) of 

IIRIRA, Congress granted to the 

Secretary of Homeland Security the 

authority to waive all legal requirements 

that he determines are necessary to 

ensure the expeditious construction of 

barriers and roads authorized by section 

102 of IIRIRA. On February 20, 2020, 

the Secretary of Homeland Security 

issued waivers for legal requirements 

covering border barrier activities 

directly in the vicinity of the Texas 

hornshell’s known range (85 FR 9794). 


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Exclusions Based on Other Relevant 

Impacts 

Under section 4(b)(2) of the Act, we 

consider any other relevant impacts, in 

addition to economic impacts and 

impacts on national security. We 

consider a number of factors including 

whether there are permitted 

conservation plans covering the species 

in the area such as habitat conservation 

plans, safe harbor agreements, or 

CCAAs, or whether there are nonpermitted conservation agreements and 

partnerships that would be encouraged 

by designation of, or exclusion from, 

critical habitat. In addition, we look at 

the existence of tribal conservation 

plans and partnerships and consider the 

government-to-government relationship 

of the United States with tribal entities. 

We have been in contact with the 

Kickapoo Traditional Tribe of Texas 

during the development of this 

proposed rule and will continue to do 

so during the development of final 

critical habitat. We also consider any 

social impacts that might occur because 

of the designation. 

Public Hearings 

We have scheduled a public 

informational meeting and public 

hearing on this proposed rule to 

designate critical habitat for the Texas 

hornshell. We will hold the public 

informational meeting and public 

hearing on the date and at the times 

listed above under Public informational 

meeting and public hearing in DATES. 

We are holding the public informational 

meeting and public hearing via the 

Zoom online video platform and via 

teleconference so that participants can 

attend remotely. For security purposes, 

registration is required. To listen and 

view the meeting and hearing via Zoom, 

listen to the meeting and hearing by 

telephone, or provide oral public 

comments at the public hearing by 

Zoom or telephone, you must register. 

For information on how to register, or if 

you encounter problems joining Zoom 

the day of the meeting, visit https://

www.fws.gov/southwest/. Registrants 

will receive the Zoom link and the 

telephone number for the public 

informational meeting and public 

hearing. If applicable, interested 

members of the public not familiar with 

the Zoom platform should view the 

Zoom video tutorials (https://

support.zoom.us/hc/en-us/articles/ 

206618765-Zoom-video-tutorials) prior 

to the public informational meeting and 

public hearing. 

The public hearing will provide 

interested parties an opportunity to 

present verbal testimony (formal, oral 

comments) regarding this proposed rule. 

While the public informational meeting 

will be an opportunity for dialogue with 

the Service, the public hearing is not: It 

is a forum for accepting formal verbal 

testimony. In the event there is a large 

attendance, the time allotted for oral 

statements may be limited. Therefore, 

anyone wishing to make an oral 

statement at the public hearing for the 

record is encouraged to provide a 

prepared written copy of their statement 

to us through the Federal eRulemaking 

Portal, or U.S. mail (see ADDRESSES, 

above). There are no limits on the length 

of written comments submitted to us. 

Anyone wishing to make an oral 

statement at the public hearing must 

register before the hearing (https://

www.fws.gov/southwest/). The use of a 

virtual public hearing is consistent with 

our regulations at 50 CFR 424.16(c)(3). 

Required Determinations 

Regulatory Planning and Review 

(Executive Orders 12866 and 13563) 

Executive Order 12866 provides that 

the Office of Information and Regulatory 

Affairs (OIRA) in the Office of 

Management and Budget will review all 

significant rules. OIRA has determined 

that this rule is not significant. 

Executive Order 13563 reaffirms the 

principles of E.O. 12866 while calling 

for improvements in the nation’s 

regulatory system to promote 

predictability, to reduce uncertainty, 

and to use the best, most innovative, 

and least burdensome tools for 

achieving regulatory ends. The 

executive order directs agencies to 

consider regulatory approaches that 

reduce burdens and maintain flexibility 

and freedom of choice for the public 

where these approaches are relevant, 

feasible, and consistent with regulatory 

objectives. E.O. 13563 emphasizes 

further that regulations must be based 

on the best available science and that 

the rulemaking process must allow for 

public participation and an open 

exchange of ideas. We have developed 

this rule in a manner consistent with 

these requirements. 

Regulatory Flexibility Act (5 U.S.C. 601 

et seq.) 

Under the Regulatory Flexibility Act 

(RFA; 5 U.S.C. 601 et seq.), as amended 

by the Small Business Regulatory 

Enforcement Fairness Act of 1996 

(SBREFA; 5 U.S.C. 801 et seq.), 

whenever an agency is required to 

publish a notice of rulemaking for any 

proposed or final rule, it must prepare 

and make available for public comment 

a regulatory flexibility analysis that 

describes the effects of the rule on small 

entities (i.e., small businesses, small 

organizations, and small government 

jurisdictions). However, no regulatory 

flexibility analysis is required if the 

head of the agency certifies the rule will 

not have a significant economic impact 

on a substantial number of small 

entities. The SBREFA amended the RFA 

to require Federal agencies to provide a 

certification statement of the factual 

basis for certifying that the rule will not 

have a significant economic impact on 

a substantial number of small entities. 

According to the Small Business 

Administration, small entities include 

small organizations such as 

independent nonprofit organizations; 

small governmental jurisdictions, 

including school boards and city and 

town governments that serve fewer than 

50,000 residents; and small businesses 

(13 CFR 121.201). Small businesses 

include manufacturing and mining 

concerns with fewer than 500 

employees, wholesale trade entities 

with fewer than 100 employees, retail 

and service businesses with less than $5 

million in annual sales, general and 

heavy construction businesses with less 

than $27.5 million in annual business, 

special trade contractors doing less than 

$11.5 million in annual business, and 

agricultural businesses with annual 

sales less than $750,000. To determine 

if potential economic impacts to these 

small entities are significant, we 

considered the types of activities that 

might trigger regulatory impacts under 

this designation as well as types of 

project modifications that may result. In 

general, the term ‘‘significant economic 

impact’’ is meant to apply to a typical 

small business firm’s business 

operations. 

The Service’s current understanding 

of the requirements under the RFA, as 

amended, and following recent court 

decisions, is that Federal agencies are 

required to evaluate the potential 

incremental impacts of rulemaking only 

on those entities directly regulated by 

the rulemaking itself, and therefore, not 

required to evaluate the potential 

impacts to indirectly regulated entities. 

The regulatory mechanism through 

which critical habitat protections are 

realized is section 7 of the Act, which 

requires Federal agencies, in 

consultation with the Service, to ensure 

that any action authorized, funded, or 

carried out by the Agency is not likely 

to destroy or adversely modify critical 

habitat. Therefore, under section 7, only 

Federal action agencies are directly 

subject to the specific regulatory 

requirement (avoiding destruction and 

adverse modification) imposed by 

critical habitat designation. 

Consequently, it is our position that 


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Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30901 

only Federal action agencies will be 

directly regulated by this designation. 

There is no requirement under the RFA 

to evaluate the potential impacts to 

entities not directly regulated. 

Moreover, Federal agencies are not 

small entities. Therefore, because no 

small entities are directly regulated by 

this rulemaking, the Service certifies 

that, if promulgated, the proposed 

critical habitat designation will not have 

a significant economic impact on a 

substantial number of small entities. 

In summary, we have considered 

whether the proposed designation 

would result in a significant economic 

impact on a substantial number of small 

entities. For the above reasons and 

based on currently available 

information, we certify that, if 

promulgated, the proposed critical 

habitat designation would not have a 

significant economic impact on a 

substantial number of small business 

entities. Therefore, an initial regulatory 

flexibility analysis is not required. 

Energy Supply, Distribution, or Use— 

Executive Order 13211 

Executive Order 13211 (Actions 

Concerning Regulations That 

Significantly Affect Energy Supply, 

Distribution, or Use) requires agencies 

to prepare Statements of Energy Effects 

when undertaking certain actions. Oil 

and gas leases occur within the 

watershed of both subunits in Unit 1: 

Pecos Tributary Unit. We do not expect 

designation of critical habitat for the 

Texas hornshell to significantly affect 

the production under these leases 

because we anticipate most companies 

will participate in the voluntary 

conservation measures provided in the 

CCAA. Further, in our economic 

analysis, we did not find that the 

designation of this proposed critical 

habitat will significantly affect energy 

supplies, distribution, or use. Therefore, 

this action is not a significant energy 

action, and no Statement of Energy 

Effects is required. 

Unfunded Mandates Reform Act (2 

U.S.C. 1501 et seq.) 

In accordance with the Unfunded 

Mandates Reform Act (2 U.S.C. 1501 et 

seq.), we make the following findings: 

(1) This rule will not produce a 

Federal mandate. In general, a Federal 

mandate is a provision in legislation, 

statute, or regulation that would impose 

an enforceable duty upon State, local, or 

tribal governments, or the private sector, 

and includes both ‘‘Federal 

intergovernmental mandates’’ and 

‘‘Federal private sector mandates.’’ 

These terms are defined in 2 U.S.C. 

658(5)–(7). ‘‘Federal intergovernmental 

mandate’’ includes a regulation that 

‘‘would impose an enforceable duty 

upon State, local, or tribal governments’’ 

with two exceptions. It excludes ‘‘a 

condition of Federal assistance.’’ It also 

excludes ‘‘a duty arising from 

participation in a voluntary Federal 

program,’’ unless the regulation ‘‘relates 

to a then-existing Federal program 

under which $500,000,000 or more is 

provided annually to State, local, and 

tribal governments under entitlement 

authority,’’ if the provision would 

‘‘increase the stringency of conditions of 

assistance’’ or ‘‘place caps upon, or 

otherwise decrease, the Federal 

Government’s responsibility to provide 

funding,’’ and the State, local, or tribal 

governments ‘‘lack authority’’ to adjust 

accordingly. At the time of enactment, 

these entitlement programs were: 

Medicaid; Aid to Families with 

Dependent Children work programs; 

Child Nutrition; Food Stamps; Social 

Services Block Grants; Vocational 

Rehabilitation State Grants; Foster Care, 

Adoption Assistance, and Independent 

Living; Family Support Welfare 

Services; and Child Support 

Enforcement. ‘‘Federal private sector 

mandate’’ includes a regulation that 

‘‘would impose an enforceable duty 

upon the private sector, except (i) a 

condition of Federal assistance or (ii) a 

duty arising from participation in a 

voluntary Federal program.’’ 

The designation of critical habitat 

does not impose a legally binding duty 

on non-Federal government entities or 

private parties. Under the Act, the only 

regulatory effect is that Federal agencies 

must ensure that their actions do not 

destroy or adversely modify critical 

habitat under section 7. While nonFederal entities that receive Federal 

funding, assistance, or permits, or that 

otherwise require approval or 

authorization from a Federal agency for 

an action, may be indirectly impacted 

by the designation of critical habitat, the 

legally binding duty to avoid 

destruction or adverse modification of 

critical habitat rests squarely on the 

Federal agency. Furthermore, to the 

extent that non-Federal entities are 

indirectly impacted because they 

receive Federal assistance or participate 

in a voluntary Federal aid program, the 

Unfunded Mandates Reform Act would 

not apply, nor would critical habitat 

shift the costs of the large entitlement 

programs listed above onto State 

governments. 

(2) We do not believe that this rule 

will significantly or uniquely affect 

small governments because small 

governments will be affected only to the 

extent that any programs having Federal 

funds, permits, or other authorized 

activities must ensure that their actions 

will not adversely affect the critical 

habitat. Therefore, a Small Government 

Agency Plan is not required. 

Takings—Executive Order 12630 

In accordance with E.O. 12630 

(Government Actions and Interference 

with Constitutionally Protected Private 

Property Rights), we have analyzed the 

potential takings implications of 

designating critical habitat for the Texas 

hornshell in a takings implications 

assessment. The Act does not authorize 

the Service to regulate private actions 

on private lands or confiscate private 

property as a result of critical habitat 

designation. Designation of critical 

habitat does not affect land ownership, 

or establish any closures, or restrictions 

on use of or access to the designated 

areas. Furthermore, the designation of 

critical habitat does not affect 

landowner actions that do not require 

Federal funding or permits, nor does it 

preclude development of habitat 

conservation programs or issuance of 

incidental take permits to permit actions 

that do require Federal funding or 

permits to go forward. However, Federal 

agencies are prohibited from carrying 

out, funding, or authorizing actions that 

would destroy or adversely modify 

critical habitat. A takings implications 

assessment has been completed and 

concludes that this designation of 

critical habitat for Texas hornshell does 

not pose significant takings implications 

for lands within or affected by the 

designation. 

Federalism—Executive Order 13132 

In accordance with E.O. 13132 

(Federalism), this proposed rule does 

not have significant Federalism effects. 

A Federalism assessment is not 

required. In keeping with Department of 

the Interior and Department of 

Commerce policy, we request 

information from, and coordinated 

development of this proposed critical 

habitat designation with, appropriate 

State resource agencies in New Mexico 

and Texas. From a federalism 

perspective, the designation of critical 

habitat directly affects only the 

responsibilities of Federal agencies. The 

Act imposes no other duties with 

respect to critical habitat, either for 

States and local governments, or for 

anyone else. As a result, the rule does 

not have substantial direct effects either 

on the States, or on the relationship 

between the national government and 

the States, or on the distribution of 

powers and responsibilities among the 

various levels of government. The 

designation may have some benefit to 

these governments because the areas 


khammond on DSKJM1Z7X2PROD with PROPOSALS
30902 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

that contain the features essential to the 

conservation of the species are more 

clearly defined, and the physical or 

biological features of the habitat 

necessary to the conservation of the 

species are specifically identified. This 

information does not alter where and 

what federally sponsored activities may 

occur. However, it may assist these local 

governments in long-range planning 

(because these local governments no 

longer have to wait for case-by-case 

section 7 consultations to occur). 

Where State and local governments 

require approval or authorization from a 

Federal agency for actions that may 

affect critical habitat, consultation 

under section 7(a)(2) would be required. 

While non-Federal entities that receive 

Federal funding, assistance, or permits, 

or that otherwise require approval or 

authorization from a Federal agency for 

an action, may be indirectly impacted 

by the designation of critical habitat, the 

legally binding duty to avoid 

destruction or adverse modification of 

critical habitat rests squarely on the 

Federal agency. 

Civil Justice Reform—Executive Order 

12988 

In accordance with Executive Order 

12988 (Civil Justice Reform), the Office 

of the Solicitor has determined that the 

rule does not unduly burden the judicial 

system and that it meets the 

requirements of sections 3(a) and 3(b)(2) 

of the Order. We have proposed 

designating critical habitat in 

accordance with the provisions of the 

Act. To assist the public in 

understanding the habitat needs of the 

species, the rule identifies the elements 

of physical or biological features 

essential to the conservation of the 

species. The designated areas of critical 

habitat are presented on maps, and the 

rule provides several options for the 

interested public to obtain more 

detailed location information, if desired. 

Paperwork Reduction Act of 1995 (44 

U.S.C. 3501 et seq.) 

This rule does not contain any new 

collections of information that require 

approval by OMB under the Paperwork 

Reduction Act of 1995 (44 U.S.C. 3501 

et seq.). This rule will not impose 

recordkeeping or reporting requirements 

on State or local governments, 

individuals, businesses, or 

organizations. An agency may not 

conduct or sponsor, and a person is not 

required to respond to, a collection of 

information unless it displays a 

currently valid OMB control number. 

National Environmental Policy Act (42 

U.S.C. 4321 et seq.) 

It is our position that, outside the 

jurisdiction of the U.S. Court of Appeals 

for the Tenth Circuit, we do not need to 

prepare environmental analyses 

pursuant to the National Environmental 

Policy Act (NEPA; 42 U.S.C. 4321 et 

seq.) in connection with designating 

critical habitat under the Act. We 

published a notice outlining our reasons 

for this determination in the Federal 

Register on October 25, 1983 (48 FR 

49244). This position was upheld by the 

U.S. Court of Appeals for the Ninth 

Circuit (Douglas County v. Babbitt, 48 

F.3d 1495 (9th Cir. 1995), cert. denied 

516 U.S. 1042 (1996)).] However, when 

the range of the species includes States 

within the Tenth Circuit, such as that of 

the Texas hornshell, under the Tenth 

Circuit ruling in Catron County Board of 

Commissioners v. U.S. Fish and Wildlife 

Service, 75 F.3d 1429 (10th Cir. 1996), 

we undertake a NEPA analysis for 

critical habitat designation. We invite 

the public to comment on the extent to 

which this proposed regulation may 

have a significant impact on the human 

environment, or fall within one of the 

categorical exclusions for actions that 

have no individual or cumulative effect 

on the quality of the human 

environment. We will complete our 

analysis, in compliance with NEPA, 

before finalizing this proposed rule. 

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), Executive 

Order 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 

recognized Federal Tribes on a 

government-to-government basis. In 

accordance with Secretarial 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. 

There are tribal lands in Texas 

included in this proposed designation of 

critical habitat. The Kickapoo Indian 

Reservation of Texas owns 1.3 km (0.8 

mi) adjacent to the Rio Grande in the 

Rio Grande–Eagle Pass Reach subunit. 

Using the criteria found in the Criteria 

Used To Identify Critical Habitat 

section, we have determined that all of 

the areas proposed for designation on 

tribal lands are essential to the 

conservation of the species. We will 

seek government-to-government 

consultation with these tribes 

throughout the proposal and 

development of the final designation of 

Texas hornshell critical habitat. 

Clarity of the Rule 

We are required by Executive Orders 

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. 

References Cited 

A complete list of references cited in 

this rulemaking is available on the 

internet at http://www.regulations.gov 

and upon request from the Texas 

Coastal Ecological Services Field Office 

(see FOR FURTHER INFORMATION CONTACT). 

Authors 

The primary authors of this proposed 

rulemaking are the staff members of the 

Texas Coastal Ecological Services Field 

Office. 

List of Subjects in 50 CFR Part 17 

Endangered and threatened species, 

Exports, Imports, Reporting and 

recordkeeping requirements, 

Transportation. 

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: 


khammond on DSKJM1Z7X2PROD with PROPOSALS
Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30903 

PART 17—ENDANGERED AND 

THREATENED WILDLIFE AND PLANTS 

■ 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. 

■ 2. Amend § 17.11(h), the List of 

Endangered and Threatened Wildlife, by 

revising the entry for ‘‘Hornshell, 

Texas’’ under CLAMS to read as 

follows: 

§ 17.11 Endangered and threatened 

wildlife. 

* * * * * 

(h) * * * 

Common name Scientific name Where listed Status Listing citations and applicable 

rules 

*******

Clams 

*******

Hornshell, Texas ............... Popenaias popeii .................... Wherever found ...................... E 83 FR 5720, 2/9/2018; 50 

CFR 17.95(f).CH

* * * * * * * 

* * * * * 

■ 3. In § 17.95, amend paragraph (f) by 

adding an entry for ‘‘Texas Hornshell 

Popenaias popeii),’’ after the entry for 

‘‘Carolina Heelsplitter (Lasmigona 

decorata)’’, to read as follows: 

§ 17.95 Critical habitat—fish and wildlife. 

* * * * * 

(f) Clams and snails. 

* * * * * 

Texas Hornshell (Popenaias popeii) 

(1) Critical habitat units are depicted 

for Eddy County, New Mexico, and in 

Brewster, Culberson, Kinney, Maverick, 

Terrell, Val Verde, and Webb Counties, 

Texas, on the maps in this entry. 

(2) Within these areas, the physical or 

biological features essential to the 

conservation of the Texas hornshell 

consist of a riverine system that 

includes: 

(i) Flowing water at rates high enough 

to support clean-swept substrate but not 

so high as to dislodge individuals; 

(ii) Crevices beneath boulders, 

shelves, and within undercut banks 

with seams of fine sediment; 

(iii) River carpsucker (Carpiodes 

carpio), red shiner (Cyprinella 

lutrensis), and gray redhorse 

(Moxostoma congestum) present; and 

(iv) Water quality parameters within 

the following ranges: 

(A) Salinity below 0.9 ppt; 

(B) Ammonia below 0.7 mg/L; 

(C) Low levels of contaminants; and 

(D) Dissolved oxygen levels within 

substrate >1.3mg/L. 

(3) Critical habitat does not include 

manmade structures (such as buildings, 

aqueducts, runways, roads, and other 

paved areas) and the land on which they 

are located existing within the legal 

boundaries on [EFFECTIVE DATE OF 

THE FINAL RULE]. 

(4) Data layers defining map units 

were created using U.S. Geological 

Survey digital ortho-photo quarterquadrangles, and critical habitat units 

were then mapped using Universal 

Transverse Mercator (UTM) Zone 15N 

coordinates. The maps in this entry, as 

modified by any accompanying 

regulatory text, establish the boundaries 

of the critical habitat designation. The 

coordinates or plot points or both on 

which each map is based are available 

to the public at the Service’s internet 

site, https://www.fws.gov/southwest/es/ 

TexasCoastal/, at http://

www.regulations.gov in Docket No. 

FWS–R2–ES–2018–0021, and at the 

field office responsible for this 

designation. You may obtain field office 

location information by contacting one 

of the Service regional offices, the 

addresses of which are listed at 50 CFR 

2.2. 

(5) Note: Index map follows: 

BILLING CODE 4333–15–P 


khammond on DSKJM1Z7X2PROD with PROPOSALS
30904 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

(6) Unit 1: Pecos Tributary Unit, Eddy 

County, New Mexico, and Culberson 

County, Texas. 

(i) Unit 1 consists of two subunits: 

Subunit 1a (Black River Subunit) 

contains 15.6 km (9.7 mi) in Eddy 

County, New Mexico, and is composed 

of lands in private ownership; Subunit 

1b (Delaware River Subunit) contains 

50.0 km (31.1 mi) in Eddy County, New 

Mexico, and Culberson County, Texas, 

and is composed of lands in Federal 

(13.2 km (8.2 mi)) and private (36.8 km 

(22.9 mi)) ownership. 

(ii) Map of Unit 1, Pecos Tributary 

Unit, Eddy County, New Mexico, and 

Culberson County, Texas, follows: 


khammond on DSKJM1Z7X2PROD with PROPOSALSEP10JN21.006</GPH>

0 25 50 75 Miles 

I I I I 

0 25 50 75 l<llometers 

-

Critical Habitat 

c::::::, 

CJ State Boundaries 

Counties 

County Boundaries 
Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30905 

(7) Unit 2: Pecos River Unit, Val 

Verde and Terrell Counties, Texas. 

(i) Unit 2 consists of 137.9 km (85.7 

mi) in Val Verde and Terrell Counties, 

Texas, and is composed of lands in 

Federal (2.7 km (1.7 mi)), nongovernmental organization (7.6 km (4.7 

mi)), and private (127.6 km (79.3 mi)) 

ownership. 

(ii) Map of Unit 2, Pecos River Unit, 

Val Verde and Terrell Counties, Texas, 

follows: 


khammond on DSKJM1Z7X2PROD with PROPOSALSEP10JN21.007</GPH>

-... _.,. __ -

Texas Homshell Cnt1cal Habitat 

Unit 1 - Pecos Tributa1·y 

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ml..akes 

= Selected Roads 

CJ County Boundaries 

CJ Slate Boundaries. 
30906 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

(8) Unit 3: Devils River Unit, Val 

Verde County, Texas. 

(i) Unit 3 consists of 53.1 km (33.0 mi) 

in Val Verde County, Texas, and is 

composed of lands in Federal (2.6 km 

(1.6 mi)), State (1.6 km (1.0 mi)), nongovernmental organization (16.7 km 

(10.4 mi)), and private (32.2 km (20.0 

mi)) ownership. 

(ii) Map of Unit 3, Devils River Unit, 

Val Verde County, Texas, follows: 


khammond on DSKJM1Z7X2PROD with PROPOSALSEP10JN21.008</GPH>

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Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30907 

(9) Unit 4: Rio Grande—Lower 

Canyons Unit, Terrell, Brewster, and Val 

Verde Counties, Texas. 

(i) Unit 4 consists of two subunits: 

Subunit 4a (Lower Canyons Reach 

Subunit) contains 107.3 km (66.7 mi) in 

Terrell and Brewster Counties, Texas, 

and is composed of lands in State (7.1 

km (4.4 mi)), and Federal (100.3 km 

(62.3 mi)) ownership; Subunit 4b 

(Langtry Reach Subunit) contains 74.8 

km (46.5 mi) in Brewster and Val Verde 

Counties, Texas, and is composed of 

lands in Federal (69.8 km (43.4 mi)) and 

private (5.0 km (3.1 mi)) ownership. 

(ii) Map of Unit 4, Rio Grande—Lower 

Canyons Unit, Terrell, Brewster, and Val 

Verde Counties, Texas, follows: 


khammond on DSKJM1Z7X2PROD with PROPOSALSEP10JN21.009</GPH>

I 

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2.5 5 7.5 Miles 

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jTexasl 

Val Verde 

- Critical Habitat 

- - - - Rivecs 

~lakes 

= Roads 

County Boundaries 

CJ state Boundaries 
30908 Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 

(10) Unit 5: Rio Grande—Laredo Unit, 

Kinney, Maverick, and Webb Counties, 

Texas. 

(i) Unit 5 consists of two subunits: 

Subunit 5a (Eagle Pass Reach Subunit) 

contains 223.2 km (138.7 mi) in Kinney 

and Maverick Counties, Texas, and is 

composed of lands in city (0.8 km (0.5 

mi)), Tribal (1.3 km (0.8 mi), and private 

(221.1 km (137.4 mi)) ownership; 

Subunit 5b (Laredo Reach Subunit) 

contains 84.0 km (52.2 mi) in Webb 

County, Texas, and is composed of 

lands in city (0.5 km (0.3 mi)) and 

private (83.5 km (51.9 mi)) ownership. 

(ii) Map of Unit 5, Rio Grande–Laredo 

Unit, Kinney, Maverick, and Webb 

Counties, Texas, follows: 


khammond on DSKJM1Z7X2PROD with PROPOSALSEP10JN21.010</GPH>

90 ,,,,. "\ 

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5 

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'ffi 15 Kilom&t&m 

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= Roads 

J;ig· Cities 

D County Boundaries 

c::J State Boundaries 

, 

' I 

l 

,-

' \ 
Federal Register / Vol. 86, No. 110 / Thursday, June 10, 2021 / Proposed Rules 30909 

* * * * * 

Martha Williams, 

Principal Deputy Director, Exercising the 

Delegated Authority of the Director, U.S. Fish 

and Wildlife Service. 

[FR Doc. 2021–11966 Filed 6–9–21; 8:45 am] 

BILLING CODE 4333–15–C 


khammond on DSKJM1Z7X2PROD with PROPOSALSEP10JN21.011</GPH>

Maverick 

Subunit Sa: 

Eagle Pass Reach Dimmit 

!Nuevo Leon j 

MEXIC 

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0 10 20 30 Miles 

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0 10 20 30 Kilometers 

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Critical Habitat 

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= Roads 

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t::] State Boundaries