Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Pearl Darter, 20410-20430 [2023-07081]

Agencies

• Fish and Wildlife Service
• DEPARTMENT OF THE INTERIOR

[Federal Register Volume 88, Number 66 (Thursday, April 6, 2023)]
[Rules and Regulations]
[Pages 20410-20430]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-07081]


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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[Docket No. FWS-R4-ES-2020-0062; FF09E21000 FXES1111090FEDR 234]
RIN 1018-BE55


Endangered and Threatened Wildlife and Plants; Designation of 
Critical Habitat for Pearl Darter

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Final rule.

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SUMMARY: We, the U.S. Fish and Wildlife Service (Service), designate 
critical habitat for the pearl darter (Percina aurora) under the 
Endangered Species Act of 1973 (Act), as amended. In total, 
approximately 524 river miles (843 river kilometers) in Clarke, 
Covington, Forrest, George, Green, Lauderdale, Jackson, Jones, Newton, 
Perry, Simpson, Stone, and Wayne Counties, Mississippi, fall within the 
boundaries of the critical habitat designation. The effect of this 
regulation is to designate critical habitat for the pearl darter under 
the Act.

DATES: This rule is effective May 8, 2023.

ADDRESSES: This final rule is available on the internet at https://www.regulations.gov and on the Mississippi Ecological Services Field 
Office website at https://fws.gov/office/mississippi-ecological-services. Comments and materials we received, as well as supporting 
documentation we used in preparing this rule, are available for public 
inspection at https://www.regulations.gov at Docket No. FWS-R4-ES-2020-
0062.
    For the critical habitat designation, the coordinates or plot 
points or both from which the maps are generated are included in the 
decision file and are available at https://www.regulations.gov at 
Docket No. FWS-R4-ES-2020-0062 and on the Mississippi Ecological 
Services Field Office website at https://fws.gov/office/mississippi-ecological-services. Any additional tools or supporting information 
that we developed for this critical habitat designation will also be 
available on the Service's website set out above or at https://www.regulations.gov.

FOR FURTHER INFORMATION CONTACT: James Austin, Field Supervisor, U.S. 
Fish and Wildlife Service, Mississippi Ecological Services Field 
Office, 6578 Dogwood View Parkway, Jackson, MS 39213; telephone 601-
321-1129. Individuals in the United States who are deaf, deafblind, 
hard of hearing, or have

[[Page 20411]]

a speech disability may dial 711 (TTY, TDD, or TeleBraille) to access 
telecommunications relay services. Individuals outside the United 
States should use the relay services offered within their country to 
make international calls to the point-of-contact in the United States.

SUPPLEMENTARY INFORMATION:

Executive Summary

    Why we need to publish a rule. To the maximum extent prudent and 
determinable, we must designate critical habitat for any species that 
we determine to be an endangered or threatened species under the Act. 
Designations of critical habitat can be completed only by issuing a 
rule through the Administrative Procedure Act rulemaking process (5 
U.S.C. 551 et seq.).
    What this document does. This rule designates a total of 524 river 
miles (843 river kilometers) of critical habitat for the pearl darter 
in the Pascagoula River and Pearl River basins in Mississippi. We 
listed the pearl darter as a threatened species under the Act on 
October 20, 2017 (82 FR 43885, September 20, 2017).
    The basis for our action. Section 4(a)(3) of the Act requires the 
Secretary of the Interior (Secretary) to designate critical habitat 
concurrent with listing to the maximum extent prudent and determinable. 
Section 3(5)(A) of the Act defines critical habitat as (i) the specific 
areas within the geographical area occupied by the species, at the time 
it is listed, on which are found those physical or biological features 
(I) essential to the conservation of the species and (II) which may 
require special management considerations or protections; and (ii) 
specific areas outside the geographical area occupied by the species at 
the time it is listed, upon a determination by the Secretary that such 
areas are essential for the conservation of the species. Section 
4(b)(2) of the Act states that the Secretary must make the designation 
on the basis of the best scientific data available and after taking 
into consideration the economic impact, the impact on national 
security, and any other relevant impacts of specifying any particular 
area as critical habitat.
    Economic impacts. In accordance with section 4(d)(2) of the Act, we 
prepared an economic analysis of the impacts of designating critical 
habitat for the pearl darter. When we published the proposed rule to 
designate critical habitat, we announced, and solicited public comments 
on, the draft economic analysis (86 FR 36678, July 13, 2021).

Previous Federal Actions

    Please refer to the final listing rule for the pearl darter, which 
published in the Federal Register on September 20, 2017 (82 FR 43885), 
for a detailed description of previous Federal actions. Subsequent to 
the final listing, we proposed to designate critical habitat for the 
pearl darter on July 13, 2021 (86 FR 36678).

Peer Review

    In accordance with our peer review policy published in the Federal 
Register on July 1, 1994 (59 FR 34270) and our August 22, 2016, 
memorandum updating and clarifying the role of peer review of actions 
under the Act, we solicited independent scientific review from four 
knowledgeable individuals with scientific expertise that included 
familiarity with the pearl darter or related species, the geographic 
region in which the species occurs, the species' biological needs, 
threats to the species, and conservation biology principles. We 
received responses from two peer reviewers on the proposed critical 
habitat rule.
    We reviewed all comments we received from the peer reviewers for 
substantive issues and new information regarding critical habitat for 
the pearl darter. The peer reviewers generally concurred with our 
methods and conclusions and provided additional information and 
suggestions for clarifying and improving the accuracy of the 
information in several sections of the preamble to the proposed rule. 
Peer reviewer comments are addressed below in Summary of Changes From 
the Proposed Rule and incorporated into this final rule as appropriate.
    In addition, some of the peer reviewer comments also contained 
suggestions that were applicable to general recovery issues for the 
pearl darter, but not directly related to the critical habitat 
designation (i.e., meaning these comments are outside the scope of the 
critical habitat rule). These general comments included topics such as 
the use of reintroductions and the number of areas used as 
reintroduction sites. While these comments may not be directly 
incorporated into the critical habitat rule, we have noted the 
suggestions and look forward to working with our partners on these 
topics during recovery planning for the pearl darter.

Summary of Comments and Recommendations

    On July 13, 2021, we published in the Federal Register (86 FR 
36678) a proposed rule to designate critical habitat for the pearl 
darter and to make available the associated draft economic analysis; 
the public comment period for that proposed rule was open for 60 days, 
ending September 13, 2021. We also contacted and invited appropriate 
Federal, State, and local agencies, scientific organizations, and other 
interested parties to comment on the proposed critical habitat 
designation and draft economic analysis during the comment period. 
Notices of the availability of these documents for review and inviting 
public comment were published by The Clarion Ledger on July 17, 2021. 
We did not receive any requests for a public hearing.
    During the comment period, we received seven public comment letters 
on the proposed rule; a majority of the comments supported the 
designation, two comments opposed the designation in two separate 
areas, and most comments included suggestions on how we could refine or 
improve the designation. All substantive information provided to us 
during the comment period has been incorporated directly into this 
final rule or is addressed below.

Peer Reviewer Comments

    (1) Comment: Both peer reviewers provided comments questioning why 
Unit 2 included only the Strong River and not any of the historical 
range within the mainstem Pearl River, as doing so would increase 
redundancy within the Pearl River drainage.
    Our Response: We recognize the importance of redundancy within the 
Pearl River drainage. Based on the best available science, we 
determined that the Strong River is the only area within the Pearl 
River drainage that currently meets the criteria for unoccupied 
critical habitat (see Areas Unoccupied at the Time of Listing 
subsection below). This does not mean that areas within the mainstem 
Pearl River do not contain some or all of the physical or biological 
features essential to the conservation of the species, but rather that 
we do not have information that areas in the mainstem Pearl River meet 
the criteria for unoccupied critical habitat. The lower Strong River 
also represents the stream reach within the Pearl River drainage with 
the best potential for recovery of the species due to current 
conditions, suitability for reintroductions, and access for monitoring. 
Further evidence of the presence of physical or biological features 
within this reach of the Strong River is demonstrated by recent 
increases in other benthic fish species (e.g., frecklebelly madtom 
(Noturus munitus), crystal darter (Crystallaria asprella)) that 
declined concurrent with the extirpation of the pearl darter (Piller

[[Page 20412]]

et al. 2004, pp. 1007-1011; Wagner et al. 2018, pp. 4-5).
    As described in the proposed rule, this unit currently provides 
some of the physical or biological features essential to the 
conservation of the pearl darter, including a stable channel with 
bottom substrates of fine and coarse sand, silt, loose clay, coarse 
gravel, fine and coarse particulate organic matter, and woody debris; a 
natural hydrograph with flows to support the normal life stages of the 
pearl darter; and the species' prey sources. Successful conservation of 
the pearl darter will require the reintroduction of pearl darter within 
the species' historical range; the lower Strong River unoccupied unit 
advances this goal. Reestablishing a population in the Strong River 
will provide for increased redundancy within the historical range and 
increase the species' ecological representation. Lastly, this river 
reach also provides the potential for the pearl darter to expand its 
range into other historically occupied areas, including the mainstem 
Pearl River, which currently may be or may later become suitable, to 
ensure that the species has an adequate level of redundancy within the 
Pearl River drainage and guard against future catastrophic events.

Comments From States

    Section 4(b)(5)(A)(ii) of the Act requires the Service to give 
actual notice of any designation of lands that are considered to be 
critical habitat to the appropriate agency of each State in which the 
species is believed to occur and invite each such agency to comment on 
the proposed designation.
    (2) Comment: The Mississippi Department of Wildlife, Fisheries, and 
Parks (MDWFP) provided a comment letter in support of the designation 
of critical habitat and recommended an extension of proposed Unit 1 in 
the Chunky River. Specifically, the MDWFP provided a publication with 
survey data for pearl darter in the Chunky River (Ellwanger et al. 
2021, entire) collected after the proposed rule was published, which 
included records of adult pearl darter upstream of the previously known 
records in the Chunky River. The MDWFP requested an upstream increase 
of the critical habitat designation within the Chunky River system of 
approximately 6.5 river miles (mi) (10.5 river kilometers (km)) to the 
uppermost Highway 80 crossing in Newton County, Mississippi (32.324 
[deg]N, 88.976 [deg]W).
    Our response: We incorporated this new information and minor 
extension of critical habitat into the rule and associated economic 
analysis based on the received information. At the time of listing in 
2017, the pearl darter was known from 19 river mi (31 river km) within 
the Chunky River (82 FR 43885; September 20, 2017, p. 43888). The 2021 
detection provided by MDWFP was a result of targeted sampling within 
suitable habitat of the Chunky River (Ellwanger et al. 2021, entire), 
where targeted sampling had not previously been completed. This 
detection resulted in an expansion of the known range of the species 
within the Chunky River to 28 river mi (45 river km) of occupied 
habitat. We consider this additional mileage of stream reach to be 
occupied at the time of listing because the newly discovered segment 
upstream has the physical or biological features essential to the 
conservation of the species and there are no impediments to 
connectivity between the new occurrence record and the areas occupied 
at the time of listing. Thus, the additional mileage was likely unknown 
to be occupied at the time of listing due to a lack of targeted surveys 
for the species rather than absence of the species from this segment. 
Although previous fish surveys had been completed in this segment, they 
were not targeting the pearl darter or its habitat and may not have 
detected the species, which is difficult to detect during surveys due 
to the species' small size and rarity. As such, surveys within a 
particular reach of an occupied stream are not always definitive of the 
species' absence, which lends support for considering the 6.5 river mi 
(10.5 river km) segment as occupied at the time of listing.

Public Comments

    (3) Comment: One public commenter noted that it is not necessary 
for the Service to designate the Leaf River as critical habitat for the 
pearl darter as the existing stream management practices are adequate 
to protect the habitat used by the pearl darter and, based on data 
collected over the last 20 years, the Leaf River is a healthy habitat 
for fish and macroinvertebrates. They also note that the pearl darter 
has increased in abundance over the past 20 or more years in the Leaf 
River.
    Our Response: As directed by the Act, we proposed as critical 
habitat those specific areas occupied by the species at the time of 
listing on which are found those physical or biological features 
essential to the conservation of the species and which may require 
special management considerations or protection. Although the commenter 
suggested that abundance is increasing within the Leaf River and 
existing stream management practices are adequate to protect the 
habitat, the designation of critical habitat within the Leaf River is 
appropriate given that the segment was occupied at the time of listing 
and meets the definition of critical habitat as it has all of the 
physical or biological features essential to the conservation of the 
species. These features include: unobstructed and stable river channels 
with connected sequences of runs and bends associated with pools and 
scour holes, required substrates, a natural flow regime, adequate water 
quality conditions, and presence of a prey base.
    (4) Comment: One commenter noted that the Service should develop a 
habitat suitability index, to assess the habitat impacts on the pearl 
darter, before designation of any critical habitat.
    Our Response: As discussed above in our response to comment 3, we 
proposed as critical habitat those specific areas at the time of 
listing on which are found those physical or biological features 
essential to the conservation of the species. Further, Section 4(b)(2) 
of the Act states that the Secretary must make the designation based on 
the best scientific data available. We have used the best available 
information to determine areas that contain the physical or biological 
features essential to the conservation of the species, which are 
reflected in our proposed rule and this final designation.
    We appreciate the suggestion to develop a habitat suitability index 
for the pearl darter. Subsequent to our proposed designation of 
critical habitat, we developed a habitat suitability index following 
standard modeling approaches (Elith et al. 2006, entire; Cutler et al. 
2007, entire) using the best available science to inform the recovery 
efforts. This analysis identified areas throughout the Pascagoula River 
drainage that are considered suitable habitat and are aligned with our 
critical habitat designation (Service 2020, unpublished data).
    (5) Comment: One commenter offered information about forestry best 
management practices and the conservation benefits they provide to 
aquatic species on private, working forests and requested that the 
Service include several references supporting these benefits.
    Our Response: We recognize that silvicultural operations are widely 
implemented in accordance with State-approved best management practices 
(BMPs; as reviewed by Cristan et al. 2018, entire). We also recognize 
that the adherence to these BMPs broadly protects water quality, 
particularly related to sedimentation (as reviewed by

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Cristan et al. 2016, entire; Warrington et al. 2017, entire; and 
Schilling et al. 2021, entire) to an extent that these operations do 
not impair the species' conservation. We have included some of these 
references here in our response. In addition, in our proposed rule, we 
included the use of BMPs for forestry activities as an example of 
special management actions that would minimize or ameliorate threats to 
water quality.
    (6) Comment: One commenter stated the designation of critical 
habitat in Unit 2 is not based on the best scientific data available, 
particularly that the water quality in Unit 2 does not meet the current 
State of Mississippi criteria, and that there is not scientific support 
for the statement that there is a high potential for successful 
reintroduction into the Pearl River drainage.
    Our Response: We have identified that some of the physical or 
biological features essential to the conservation of the species can be 
found within Unit 2 in the Pearl River drainage (see Summary of 
Essential Physical or Biological Features, below). We have revised our 
description of the physical or biological features present in Unit 2 to 
reflect that the water quality physical or biological feature currently 
is not met during all portions of the year. However, Unit 2 in the 
Strong River provides some of the physical or biological features 
essential to the conservation of the pearl darter, including a stable 
channel with bottom substrates of sand, silt, loose clay and gravel, 
bedrock, fine and coarse particles of organic matter, woody debris, and 
a natural hydrograph with flows to support the normal life stages of 
the pearl darter and the species' prey sources. In addition, channel 
integrity is controlled and protected by natural bedrock outcrops, and 
improvement in water quality is indicated by the resurgence of other 
benthic fish species (e.g., frecklebelly madtom and crystal darter) 
that historically co-occurred with the pearl darter and experienced 
declines when the pearl darter disappeared from the drainage (Piller et 
al. 2004, pp. 1007-1011; Tipton et al. 2004, pp. 57-60; Wagner et al. 
2018, entire). We also acknowledge observations from a biologist that 
has worked in the Strong River since the 1970s (Hartfield 2021, pers. 
comm.) and a local landowner (Gillespie 2021, pers. comm.). Both have 
noted improvements in water quality due to a reduction in pollutants 
from chicken farming and other sources since the 1970s, presumably due 
to enactment and enforcement of the Clean Water Act of 1972, which has 
greatly improved water quality monitoring.
    The assessment that this species has high potential for successful 
reintroduction is based on the fact that the species has been 
successfully propagated in captivity (Campbell and Schwarz 2019, 
entire) and suitable habitats are still found at the type locality on 
the Strong River (Wagner 2022, pers. comm.). Suttkus et al. (1994, p. 
19) note habitat for the pearl darter in the Strong River, which is 
consistent with habitat descriptions from recent surveys in the 
Pascagoula (Slack et al. 2005, pp. 9-11; Clark et al. 2018, pp. 104-
105) and observations of the habitat currently found at the type 
locality within the Strong River (Wagner 2022, pers. comm.).
    Moreover, recent and ongoing studies have filled many of the 
previously identified knowledge gaps for the species that will inform 
successful reintroduction planning. Habitat associations have been 
studied (Clark et al. 2018, p. 103). Completed genetic work is being 
used to inform propagation and serve as a reference for reintroduction 
(Schaefer et al. 2020, entire). We are currently working with the 
University of Southern Mississippi to study the life history of the 
species through an ongoing project. Data collected through this project 
have been used to help inform the Service on the timing of spawning for 
the species, which will help to better monitor existing populations and 
any newly introduced populations. Additionally, a preliminary study of 
the diet of pearl darter has found the species not to be a specialist 
as it was noted to consume larval mayflies, caddisflies, black flies, 
and ostracods (Service 2022, unpublished data). We recognize that 
additional studies and information will help improve the reintroduction 
planning for the species although recent and ongoing studies have 
addressed many of the knowledge gaps that previously existed.
    (7) Comment: One commenter notes that the economic analysis fails 
to consider costs to projects related to mitigation measures, water 
quality issues, project modifications, and project relocations.
    Our Response: 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. In our incremental 
effects memorandum (IEM), we clarified the distinction between the 
recommendations 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 pearl darter's critical habitat. As discussed in section 3 of the 
screening analysis (Industrial Economics, Incorporated (IEc) 2020, pp. 
9-19), the Service does not anticipate making any additional project 
modification recommendations to avoid adverse modification of pearl 
darter critical habitat beyond what we already recommend to avoid 
impacts to other listed species with similar habitat requirements, 
including the Gulf sturgeon (listed as Atlantic sturgeon (Gulf 
subspecies); Acipenser oxyrinchus desotoi), ringed map turtle 
(Graptemys oculifera), and yellow blotched map turtle (Graptemys 
flavimaculata). This statement is true for both Unit 1, which is 
occupied such that the species already would be considered for 
consultation since it is listed, and Unit 2, which is unoccupied. The 
screening analysis also highlights the project recommendations 
contained in the Standard Local Operations Procedures for Endangered 
Species (SLOPES) agreement for Mississippi between the Service and the 
U.S. Army Corps of Engineers. In making this determination in our 
economic analysis, the Service considered the potential for 
recommendations that include mitigation measures, are specific to water 
quality issues, or may result in project relocations.
    (8) Comment: One commenter asserts that the economic analysis 
should consider the potential for losses in value among properties 
adjacent to the proposed river miles.
    Our Response: Existing economics literature suggests that critical 
habitat may affect property values (List et al. 2006, entire; 
Auffhammer et al. 2020, entire). This literature references particular 
species and geographic contexts, and the transferability of the results 
to other species and regions is uncertain. As described in section 4 of 
the screening analysis (IEc 2020, pp. 19-20), this literature has not 
evaluated the effects of riverine critical habitat on adjacent property 
values. While perceptional effects on land values are possible, the 
likelihood and magnitude of such effects for this rule are uncertain. 
Although the screening analysis acknowledges this uncertainty, it does 
not conclude that these effects are likely, and we did not consider 
potential impacts to property values given the lack of support in the 
available literature (IEc 2020, p. 20). Lastly, the commenter did not 
provide information or literature on potential loss in property value 
that would lead us to change our evaluation in the screening analysis.
    (9) Comment: One commenter suggests that the economic analysis

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should consider the costs associated with unrealized future development 
and lost tax revenues associated with activities in Unit 2.
    Our Response: As described in response to comment 7 above and in 
section 3 of the screening analysis (IEc 2020, pp. 9-19), the Service 
does not anticipate making project modification recommendations to 
avoid adverse modification of pearl darter critical habitat beyond what 
has already been recommended to avoid impacts to other listed species 
with similar habitat requirements, including the Gulf sturgeon and 
ringed map turtle. The costs associated with changes in development 
activity would be incurred regardless of whether critical habitat for 
the pearl darter is designated along the Strong River because of the 
presence of other listed species. Therefore, the critical habitat 
designation for the pearl darter is unlikely to affect future 
development or tax revenues in the region.
    (10) Comment: One commenter noted that the Service incorrectly 
states in the discussion of administrative costs of section 7 
consultations in the draft economic analysis that the critical habitat 
designation will not result in any additional consultations on the 
Strong River.
    Our Response: As Unit 2 overlaps with the listed range of the Gulf 
sturgeon and ringed map turtle, all activities with a Federal nexus 
that may affect pearl darter critical habitat would in fact require 
consultation even absent the critical habitat designation for the pearl 
darter in order to consider potential effects on the Gulf sturgeon and 
ringed map turtle. It is also important to note that activities 
potentially affecting critical habitat can occur outside of the area 
designated as critical habitat. Activities occurring upstream of the 
area designated as critical habitat for the Gulf sturgeon, which would 
include Unit 2, that could negatively impact water quality and then 
Gulf sturgeon critical habitat would require consultation under section 
7(a)(2) of the Act where there is a Federal nexus. For example, in 
2019, the Service consulted on a bridge replacement project situated 
along the Strong River in Simpson County and specifically considered 
the Gulf sturgeon critical habitat as well as the ringed map turtle. 
Similarly, in 2006, the Service considered both the Gulf sturgeon 
critical habitat and ringed map turtle during a consultation regarding 
a new pipeline crossing within the Strong River drainage. The proposed 
Unit 2, therefore, does benefit from the baseline protections afforded 
to other species with similar habitat needs given the connectivity of 
the Strong River with existing critical habitats on the Pearl River.

Summary of Changes From the Proposed Rule

    After consideration of the comments we received during the public 
comment period (refer to Summary of Comments and Recommendations, 
above) and new information published or obtained since the proposed 
rule was published, we made changes to the final critical habitat rule. 
Many small, non-substantive changes and corrections that do not affect 
the determination (e.g., updating the Background section of the 
preamble in response to comments, minor clarifications) were made 
throughout the document. Below is a summary of changes made to the 
final rule.

Economic Analysis

    (1) The draft economic analysis incorrectly displayed that the 
unoccupied habitat in proposed Unit 2 overlaps with the designated 
critical habitat for other species. Specifically, in Exhibit 1, Summary 
of Proposed Critical Habitat Units for the Pearl Darter, of the 
screening memo (IEc 2020, p. 6), incorrect information was displayed in 
the column Overlaps With Existing Critical Habitat For Other Aquatic or 
Riparian Listed Species under Unit 2. The ``Yes'' should have been a 
``No'' as the proposed critical habitat does not overlap with critical 
habitat for other species. This error was corrected and is addressed in 
the updated memorandum from IEc (IEc 2021, p. 1).
    (2) Updated the economic analysis to include consideration of the 
additional 6.5 river mi (10.5 river km) within Unit 1. Despite the 
increase in size of Unit 1, the total incremental costs are not 
expected to change relative to the screening analysis (IEc 2020, 
entire; IEc 2021, entire).

Preambles to the Rulemaking Documents

    The following items describe changes made between statements in the 
preamble of the proposed rule and those in the preamble of this final 
rule.
    (3) In Criteria Used To Identify Critical Habitat, based on 
feedback from a peer reviewer, we removed a statement that indicated 
the pearl darter's representation would increase from current levels by 
allowing for local environmental adaptation and increasing genetic 
representation. The Service had not provided adequate information to 
support that statement, and the species currently has low levels of 
genetic diversity within its occupied range.
    (4) In Application of the ``Adverse Modification'' Standard, we 
included a statement that, during a consultation under section 7(a)(2) 
of the Act, the Services may find that activities likely to destroy or 
adversely modify critical habitat include activities that occur within 
critical habitat or affect the critical habitat.
    (5) In Habitats Representative of the Historical, Geographical, and 
Ecological Distributions of the Species, we:
    (a) Changed a statement that the pearl darter is definitively 
extirpated to it being considered extirpated within the Pearl River 
basin, based on information from peer reviewers. Given the species' 
cryptic nature, lack of targeted surveys within the Pearl River basin, 
and the fact that extirpation is a high bar to definitively prove, 
researchers do not consider the pearl darter to be definitively 
extirpated from this system despite a lack of detections over the past 
several decades.
    (b) Added information from a habitat suitability model that was 
developed for recovery efforts (Service 2021, unpublished data), which 
confirmed that our proposed designation of critical habitat contains 
areas indicated as suitable for the species.
    (c) Incorporated additional citations--provided through the public 
comment and peer review process--to support our discussion of physical 
and biological features, species needs, and species occurrence.
    (d) Updated the calculation of the proportion of habitat lost from 
``roughly half'' to 36 percent. The updated total better accounts for 
the proportion of occupied habitat lost with the extirpation of the 
species within the Pearl River basin.
    (6) In Space for Individual and Population Growth and for Normal 
Behavior, we removed the description of the habitat for the prey of 
pearl darter and described only habitat as found in recent literature 
(Slack et al. 2005, pp. 9, 11).
    (7) In Food, Water, Air, Light, Minerals, or Other Nutritional or 
Physiological Requirements section and Summary of Essential Physical or 
Biological Features, we incorporated information from a recent 
preliminary diet study (Service, unpublished data) of specimens from 
the Chunky River and Chickasawhay River. This study confirmed that the 
pearl darter is a dietary generalist.
    (8) In Sites for Breeding, Reproduction, or Rearing (or 
Development) of Offspring, we incorporated information that indicates

[[Page 20415]]

that spawning has not been observed in the wild, but rather individuals 
in spawning condition have been collected.
    (9) In Areas Occupied at the Time of Listing, we have incorporated 
information from two additional citations (Clark et al. 2018, entire; 
Ellwanger et al. 2021, entire) that add known distribution information 
for the species.
    (10) In Final Critical Habitat Designation, we have revised our 
description of the physical or biological features present in Unit 2 to 
reflect our recognition that the physical or biological feature 
pertaining to water quality is not currently met during all portions of 
the year.

Rule Text

    (11) In the rule portion of this document we have made the 
following changes:
    (a) In the list of the physical or biological features required for 
the pearl darter, we adjusted the descriptions of the bottom substrates 
and prey base, based on information received during the comment period; 
and,
    (b) In the designation of critical habitat for Unit 1, we expanded 
the designation in the Chunky River based on information submitted by 
the Mississippi Department of Wildlife, Fisheries, and Parks as 
described above in the response to comment 2.

I. 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.
    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).
    This critical habitat designation was proposed when the regulations 
defining ``habitat'' (85 FR 81411; December 16, 2020) and governing the 
4(b)(2) exclusion process for the Service (85 FR 82376; December 18, 
2020) were in place and in effect. However, those two regulations have 
been rescinded (87 FR 37757; June 24, 2022, and 87 FR 43433; July 21, 
2022) and no longer apply to any designations of critical habitat. 
Therefore, for this final rule designating critical habitat for the 
pearl darter, we apply the regulations at 50 CFR 424.19 and the 2016 
Joint Policy on 4(b)(2) exclusions (81 FR 7226; February 11, 2016).
    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 
non-Federal landowners. Where a landowner requests Federal agency 
funding or authorization for an action that may affect a listed species 
or critical habitat, the Federal agency would be required to consult 
with the Service under section 7(a)(2) of the Act. However, even if the 
Service were to conclude that the proposed activity would likely result 
in destruction or adverse modification of the critical habitat, the 
Federal action agency and the landowner are not required to abandon the 
proposed activity, or to restore or recover the species; instead, they 
must implement ``reasonable and prudent alternatives'' to avoid 
destruction or adverse modification of critical habitat.
    Under the first prong of the Act's definition of critical habitat, 
areas within the geographical area occupied by the species at the time 
it was listed are included in a critical habitat designation if they 
contain physical or biological features (1) which are essential to the 
conservation of the species and (2) which may require special 
management considerations or protection. For these areas, critical 
habitat designations identify, to the extent known using the best 
scientific 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).
    Under the second prong of the Act's definition of critical habitat, 
we can designate critical habitat in areas outside the geographical 
area occupied by the species at the time it is listed, upon a 
determination that such areas are essential for the conservation of the 
species.
    Section 4 of the Act requires that we designate critical habitat on 
the basis of the best scientific data available. Further, our Policy on 
Information Standards Under the Endangered Species Act (published in 
the Federal Register on July 1, 1994 (59 FR 34271)), the Information 
Quality Act (section 515 of the Treasury and General Government 
Appropriations Act for Fiscal Year 2001 (Pub. L. 106-554; H.R. 5658)), 
and our associated Information Quality Guidelines provide criteria, 
establish procedures, and provide guidance to ensure that our decisions 
are based on the best scientific data available. They require our 
biologists, to the extent consistent with the Act and with the use of 
the best scientific data available, to use primary and original sources 
of information as the basis for recommendations to designate critical 
habitat.
    When we are determining which areas should be designated as 
critical habitat, our primary source of information is generally the 
information 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

[[Page 20416]]

materials; or experts' opinions or personal knowledge.
    Habitat is dynamic, and species may move from one area to another 
over time. We recognize that critical habitat designated at a 
particular point in time may not include all of the habitat areas that 
we may later determine are necessary for the recovery of the species. 
For these reasons, a critical habitat designation does not signal that 
habitat outside the designated area is unimportant or may not be needed 
for recovery of the species. Areas that are important to the 
conservation of the species, both inside and outside the critical 
habitat designation, will continue to be subject to: (1) Conservation 
actions implemented under section 7(a)(1) of the Act; (2) regulatory 
protections afforded by the requirement in section 7(a)(2) of the Act 
for Federal agencies to ensure their actions are not likely to 
jeopardize the continued existence of any endangered or threatened 
species; and (3) the prohibitions found in section 9 of the Act. 
Federally funded or permitted projects affecting listed species outside 
their designated critical habitat areas may still result in jeopardy 
findings in some cases. These protections and conservation tools will 
continue to contribute to recovery of the species. Similarly, critical 
habitat designations made on the basis of the best available 
information at the time of designation will not control the direction 
and substance of future recovery plans, habitat conservation plans 
(HCPs), or other species conservation planning efforts if new 
information available at the time of those planning efforts calls for a 
different outcome.

Prudency and Determinability

    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. In our proposed critical habitat rule (86 FR 36678; July 13, 
2021), we found that designating critical habitat is both prudent and 
determinable for the pearl darter. In this final rule, we reaffirm 
those determinations.

Physical or Biological Features Essential to the Conservation of the 
Species

    In accordance with section 3(5)(A)(i) of the Act and regulations at 
50 CFR 424.12(b), in determining which areas we will designate as 
critical habitat from within the geographical area occupied by the 
species at the time of listing, 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 essential to the conservation of the species 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 absence of 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 essential 
to support the life history of the species.
    In considering whether features are essential to the conservation 
of the species, we 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.

Habitats Representative of the Historical, Geographical, and Ecological 
Distributions of the Species

    The pearl darter is historically known from rivers and streams 
within the Pearl River and Pascagoula River drainages in Mississippi 
and Louisiana, and the species was described from the lower Strong 
River within the Pearl River drainage of Mississippi (Suttkus et al. 
1994, pp. 15-20). The darter has been considered extirpated from the 
Pearl River drainage for several decades apparently due to system-wide 
channel and water quality degradation occurring in the late 1960s to 
early 1970s (Kuhajda 2009, pp. 17-18; Wagner et al. 2017, entire). With 
this presumed extirpation, 36 percent of the historical, geographical, 
and ecological habitats of the pearl darter are no longer occupied. 
Channel integrity and water quality within the Pearl River drainage 
have since improved due to the enactment of State and Federal laws and 
regulations addressing water pollution and in-channel sand and gravel 
mining. In the lower Strong River, channel integrity is controlled and 
protected by natural bedrock outcrops, and water quality has improved 
as indicated by the resurgence of other benthic fish species that 
historically co-occurred with the pearl darter (Piller et al. 2004, pp. 
1007-1011; Tipton et al. 2004, pp. 57-60; Wagner et al. 2018, entire).
    Within the Pascagoula River drainage, the pearl darter is known to 
occur within the Pascagoula, Chickasawhay, Leaf, Chunky, and Bouie 
Rivers and the Okatoma and Black Creeks (Suttkus et al. 1994, pp. 15-
20; Wagner et al. 2017, pp. 3-10, 12; Clark et al. 2018, pp. 100-103; 
Schaefer et al. 2020, pp. 26-27, 43-44). This area was reaffirmed as 
suitable habitat throughout a contiguous distribution based on a 
habitat suitability model developed for the species (Service 2021, 
unpublished data).
    The lower Strong River within the Pearl River drainage and the 
rivers and streams identified above within the Pascagoula River 
drainage are representative of the historical, geographical, and 
ecological distribution of the species.

Space for Individual and Population Growth and for Normal Behavior

    The pearl darter is found in free-flowing, low-gradient streams and 
rivers with pools and scour holes associated with channel bends and 
runs (Slack et al. 2002, p. 10; Bart et al. 2001, p. 13). Presence of 
the darter is associated with bottom substrates including fine and 
coarse sand, silt, loose clay, coarse gravel, fine and coarse 
particulate organic matter, and woody debris (Slack et al. 2005, pp. 9, 
11). Pearl darter occurrence within these habitats may be seasonal with 
spawning occurring in upstream reaches and growth and

[[Page 20417]]

recruitment in downstream reaches (Bart et al. 2001, pp. 13, 15). 
Therefore, a continuum of perennial, uninterrupted, and interconnected 
natural small stream-to-river channel habitat is required for 
downstream drift of larvae or movement of juveniles and upstream 
migration of spawning adults.

Food, Water, Air, Light, Minerals, or Other Nutritional or 
Physiological Requirements

    The pearl darter requires unimpeded and interconnected stretches of 
perennial and flowing streams and rivers with adequate water quality. 
Water temperatures at pearl darter collection sites have ranged from 8 
to 30 degrees Celsius ([deg]C) (46.4 to 86.0 degrees Fahrenheit 
([deg]F)) (Suttkus et al. 1994, pp. 17-19; Bart et al. 2001, p. 13, 
Slack et al. 2002, p. 10), with dissolved oxygen of 5.8 to 9.3 
milligrams per liter (mg/1) (Suttkus et al. 1994, pp. 17-19; Bart et 
al. 2001, pp. 7, 13-14; Slack et al. 2002, p. 10). The species is 
apparently sensitive to warmer water temperatures and may seasonally 
require tributaries with canopy shading and/or cool spring flows as 
seasonal refugia from warmer, unshaded river channels (Bart et al. 
2001, p. 14).
    Preliminary analysis of diets of specimens from the Chunky River 
and Chickasawhay River show the species feeds on larval mayflies, 
larval caddisflies, larval black flies, ostracods (crustaceans), 
chironomids (midges), and gastropods (snails). Food availability is 
likely affected by adequate flow, channel stability, water quality, and 
local habitat conditions, which may vary throughout or between the 
rivers and streams occupied or historically occupied by the species. 
Pearl darter have been maintained in captivity for at least 2 years on 
a diet of bloodworms (Campbell and Schwarz 2019, entire).

Sites for Breeding, Reproduction, or Rearing (or Development) of 
Offspring

    Pearl darter have been collected at sites with cool to warm water 
temperatures (8 to 30 [deg]C (46.4 to 86.0 [deg]F)), high dissolved 
oxygen (5.8 to 9.3 mg/l), slightly acidic to basic pH values (6.3 to 
7.6), and low levels of pollution (Suttkus et al. 1994, pp. 17-19; Bart 
et al. 2001, pp. 7, 13-14; Slack et al. 2002, p. 10). Spawning has not 
been observed in the wild for pearl darter. However, adult pearl darter 
have been collected in spawning condition in the Strong River where 
they were associated with bedrock and broken rubble (Suttkus et al. 
1994, p. 19) and in three probable spawning sites in the Pascagoula 
River system that were characterized by extensive outcrops of limestone 
or sandstone (Bart and Piller 1997, p. 8). Pearl darter in spawning 
condition in the Pascagoula River drainage have also been collected 
over firm gravel in relatively shallow, flowing water from April to 
early May (Bart et al. 2001, p. 13). Ideal conditions for spawning have 
been described as channel reaches with good canopy shading, an 
extensive buffer of mature forest, and good water quality (Bart et al. 
2001, p. 15).
    Adults collected in spawning condition in the Pearl and Strong 
Rivers (Mississippi) were documented during March through May (Suttkus 
et al. 1994, pp. 19-20), and young of year were collected in June 
(Suttkus et al. 1994, p. 19). Based on collection occurrence patterns, 
some researchers have postulated that adult pearl darter migrate 
upstream during the fall and winter to spawn in suitable upstream 
gravel reaches with elevated river discharge during the spring 
dispersing the larvae and juveniles into downstream reaches (Bart et 
al. 2001, p. 14; Ross et al. 2000, p. 11). Other studies have 
hypothesized that the species disperses locally from shallow spawning 
habitats into nearby deeper habitats where their presence is more 
difficult to detect (Slack et al. 2002, p. 18). The pattern of the 
disappearance of the pearl darter from all stream orders in the Pearl 
River drainage over a relatively short period of time suggests that 
some degree of seasonal interchange between tributary and river channel 
subpopulations may have been a factor in the species' presumed 
extirpation from that drainage. Therefore, until more is known relative 
to seasonal dispersal, connectivity between instream habitats should be 
considered essential for successful breeding and rearing of the pearl 
darter.

Summary of Essential Physical or Biological Features

    We derive the specific physical or biological features essential to 
the conservation of pearl darter from studies of the species' habitat, 
ecology, and life history as described below. Additional information 
can be found in the proposed critical habitat (86 FR 36678; July 13, 
2021) and final listing rule (82 FR 43885; September 20, 2017) for the 
pearl darter. We have determined that the following physical or 
biological features are essential to the conservation of the pearl 
darter:
    (1) Unobstructed and stable stream and river channels with:
    (a) Connected sequences of channel runs and bends associated with 
pools and scour holes; and
    (b) Bottom substrates consisting of fine and coarse sand, silt, 
loose clay, coarse gravel, fine and coarse particulate organic matter, 
or woody debris.
    (2) A natural flow regime necessary to maintain instream habitats 
and their connectivity.
    (3) Water quality conditions, including cool to warm water 
temperatures (8 to 30 [deg]C (46.4 to 86.0 [deg]F)), high dissolved 
oxygen (5.8 to 9.3 mg/l), slightly acidic to basic pH (6.3 to 7.6), and 
low levels of pollutants and nutrients meeting the current State of 
Mississippi criteria as necessary to maintain natural physiological 
processes for normal behavior, growth, and viability of all life stages 
of the species.
    (4) Presence of a prey base of small aquatic macroinvertebrates, 
including larval mayflies, larval caddisflies, larval black flies, 
ostracods (crustaceans), chironomids (midges), and gastropods (snails).

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 which are essential to the conservation of 
the species and which may require special management considerations or 
protection. The pearl darter faces threats from water quality 
degradation from point and non-point source pollution, discharges from 
municipalities, and geomorphological changes to its channel habitats 
(82 FR 43885, September 20, 2017, pp. 43888-43893). The features 
essential to the conservation of this species may require special 
management considerations or protection to reduce the following 
threats: (1) Actions that alter the minimum or existing flow regime, 
including impoundment, channelization, or water diversion; (2) actions 
that significantly alter water chemistry or temperature by the release 
of chemicals, biological pollutants, or heated effluents into the 
surface water or connected groundwater at a point or non-point source; 
and (3) actions that significantly alter channel morphology or 
geometry, including channelization, impoundment, road and bridge 
construction, or instream mining.
    Examples of special management actions that would minimize or 
ameliorate threats to the pearl darter include: (a) Restoration and 
protection of riparian corridors; (b) implementation of best management 
practices to minimize erosion (such as State and industry best 
management practices for road construction, forest management,

[[Page 20418]]

or mining activities); (c) stream bank restoration projects; (d) 
private landowner programs to promote watershed and soil conservation 
(such as the U.S. Department of Agriculture's Farm Bill and the 
Service's Private Lands programs); (e) implementation of best 
management practices for storm water; and (f) upgrades to industrial 
and municipal treatment facilities to improve water quality in 
effluents.

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 designating critical 
habitat in areas within the geographical area occupied by the species 
at the time of listing. We also are designating specific areas outside 
the geographical area occupied by the species because we have 
determined that a designation limited to occupied areas would be 
inadequate--and therefore designation of unoccupied area is essential--
to ensure the conservation of the species.
    The current distribution of the pearl darter is reduced from its 
historical distribution, and we anticipate that recovery will require 
continued protection of the existing population and habitat, as well as 
establishing a population within its historical range (i.e., unoccupied 
critical habitat), to ensure there are adequate numbers of pearl darter 
occurring in stable populations for the species' continued 
conservation. Furthermore, rangewide recovery considerations, such as 
maintaining existing genetic diversity and striving for representation 
of all major portions of the species' historical range, were considered 
in formulating the proposed critical habitat designation.
    We are designating critical habitat in areas within the 
geographical area occupied by the species at the time of listing. We 
identified areas with current occurrence records that we deemed 
suitable habitat (see delineation steps, below) and that had one or 
more of the physical or biological features identified for the pearl 
darter that may require special management considerations or 
protection. We also are designating specific areas outside of the 
geographical area occupied by the species at the time of listing 
because we have determined that those areas are essential for the 
conservation of the species. For those unoccupied areas, we have 
determined that it is reasonably certain that the unoccupied areas will 
contribute to the conservation of the species and contain one or more 
of the physical or biological features that are essential to the 
conservation of the species.
    Threats to pearl darter occurring in the Pascagoula River drainage 
are compounded by the species' naturally low numbers and short life 
span, but the species' conservation potential is primarily limited by 
its extirpation from the Pearl River drainage and, therefore, its lack 
of redundancy. The documented Pearl River drainage extirpation was 
rapid and system-wide, including all mainstem and tributary collection 
sites seemingly simultaneously. As such, we consider pearl darter 
occurring within the Pascagoula River and its tributaries as a single 
population. The loss of the species' redundancy with its extirpation 
from the Pearl River drainage has also diminished its genetic and 
ecological representation and, therefore, increased the species' 
vulnerability to catastrophic events and population changes. A 
successful reintroduction into the Pearl River drainage would restore 
the species' redundancy within its historical range. Thus, 
reintroducing the species into the Pearl River drainage would 
contribute to the resilience and conservation of the pearl darter.
    Factors implicated in the Pearl River extirpation include 
geomorphic instability (i.e., channel erosion and degradation), 
sedimentation, and point source pollution from municipalities and 
industries (e.g., Bart and Suttkus 1995, p. 14; Tipton et al. 2004, pp. 
59-60). One or all of these factors may have been responsible for the 
diminishment or loss of some or all of the physical or biological 
features essential to the conservation of the pearl darter within the 
drainage (e.g., channel stability, substrate, water quality, prey 
base). We now find that these factors have been reduced to a degree 
that the pearl darter may be successfully reintroduced into the Pearl 
River.
    For example, active channel erosion and degradation that may have 
been precipitated by the 1956 construction of the Pearl River 
navigation system in the lower basin and aggravated by the 1963 
construction of the Ross Barnett Reservoir in the upper basin have 
diminished. Moreover, instream mining is now prohibited by the States 
of Mississippi and Louisiana, thus resulting in more stable channel 
habitats within the basin. In addition, point-source pollution from 
untreated municipal and industrial discharge into the Pearl River has 
been significantly reduced by enactment and enforcement of the Clean 
Water Act of 1972 (33 U.S.C. 1251 et seq.). The improvement of the 
physical or biological features within the Pearl River drainage is also 
demonstrated by recent observed increases in other benthic fish species 
(e.g., crystal darter, frecklebelly madtom), which experienced declines 
concurrent with the extirpation of the pearl darter (Piller et al. 
2004, pp. 1007-1011; Tipton et al. 2004, pp. 57-60; Wagner et al. 2018, 
p. 13). These improvements indicate that one or more of the physical or 
biological features essential to the conservation of the pearl darter 
are now present within the Pearl River drainage. Because the Pearl 
River drainage habitat contains the physical or biological features for 
the pearl darter and supports other benthic fish species with similar 
life processes, we conclude that the drainage contains the resources 
and conditions necessary to support the life processes for the pearl 
darter and is essential for the conservation of the species.
    We completed the following steps to delineate critical habitat:
    (1) Compiled all available current and historical occurrence data 
records for the pearl darter in both the Pascagoula and Pearl River 
drainages.
    (2) Used confirmed presence from 1994-2021 as the foundation for 
identifying areas currently occupied in the Pascagoula River drainage.
    (3) Evaluated habitat suitability of stream segments that contain 
the identified physical or biological features and that are currently 
occupied by the species and retained all occupied stream segments.
    (4) Evaluated unoccupied segments of the Pearl River drainage for 
suitability of spawning and recruitment, darter reintroduction, and 
monitoring and management of a reintroduced population.
    (5) Evaluated unoccupied segments of the Pearl River drainage for 
connectivity with reaches that were historically occupied and 
identified areas containing the physical or biological features 
essential to the conservation of the species that may require special 
management considerations or protection.
    Sources of data for this critical habitat designation include the 
proposed and final listing rules (81 FR 64857, September 21, 2016; 82 
FR 43885, September 20, 2017), fish collection databases provided by 
the MDWFP,

[[Page 20419]]

survey reports and observations, and peer-reviewed publications.

Areas Occupied at the Time of Listing

    We used reports and collection data to map species site collections 
and occurrences between 1994 and 2021, to determine areas occupied at 
the time of listing. Based on the best available scientific data, we 
determined that all currently known occupied habitat for the pearl 
darter was also occupied by the species at the time of listing and that 
these areas contain all of the physical or biological features 
essential to the conservation of the species although they may require 
special management considerations or protection.
    As stated above, we delineated units based on documented 
occurrences and the existing physical or biological features essential 
to the conservation of the species. Collection occurrence patterns 
suggest that adult pearl darter migrate upstream to spawn in suitable 
gravel or bedrock reaches with elevated spring river discharge 
dispersing larvae and juveniles into downstream reaches; an alternative 
hypothesis considers that the pearl darter moves from shallow, easily 
collected spawning habitats into deeper habitats where it is more 
difficult to detect the fish (see Sites for Breeding, Reproduction, or 
Rearing (or Development) of Offspring, above). While both hypotheses 
are partially supported by data, we note that the disappearance of the 
species from the Pearl River drainage occurred fairly rapidly and 
simultaneously in all stream orders, suggesting some element of 
migration may be involved in the darter's life history. To allow for 
potential seasonal movement between stream reaches, we are designating 
one continuous unit of occupied critical habitat within the Pascagoula 
River drainage. This unit includes portions of the Chunky, Bouie, Leaf, 
Chickasawhay, and Pascagoula Rivers as well as reaches of Okatoma and 
Big Black Creeks as described below under Final Critical Habitat 
Designation.
    Clark et al. (2018, entire) provides a thorough review of the 
distribution of the species from 1950 through 2016, throughout both the 
Pearl River and Pascagoula River drainages prior to the listing of the 
species in 2017. Since the 2017 listing of the species, there have been 
86 site collections of pearl darter in the Pascagoula River drainage 
(Wagner et al. 2019, pp. 8-18; Schaefer et al. 2020, pp. 26-27, 43-44; 
Ellwanger et al. 2021, p. 5). One of these collections in 2018 extended 
the known range approximately 60 mi (97 km) in Black Creek, above its 
confluence with the occupied reach of Big Black Creek (Schaefer et al. 
2020, pp. 26-27). An additional collection in 2021 extended the known 
historical range approximately 4.0 river mi (6.4 river km) upstream in 
the Chunky River, which is upstream of the second-most upstream State 
Highway 80 and Chunky River crossing (Ellwanger et al. 2021, p. 10). We 
consider this additional mileage of stream reach to be occupied at the 
time of listing because the reaches between the previously identified 
populations in Big Black Creek or Chunky River and the newly discovered 
populations upstream both have the physical or biological features 
essential to the conservation of the species and its potential seasonal 
migration. Further, there are no impediments to connectivity between 
the new occurrence records and the areas that were known to be occupied 
when the species was listed in 2017. The potential for seasonal 
migration, the species' small size and rarity, and the fact that 
surveys for the pearl darter are difficult and not always definitive of 
the species' absence within a particular reach of an occupied stream 
also support considering this area occupied at the time of listing.
    In making these determinations, we recognize that collection sites 
for the pearl darter occur at areas generally accessible to fish 
biologists and that occupied habitats within a river reach may vary 
depending upon life stage, stream size, and season. Additionally, 
stream habitats are highly dependent upon upstream and downstream 
channel habitat conditions for their maintenance. Therefore, we 
considered the areas occupied at the time of listing to extend from an 
identifiable landmark (e.g., bridge crossing, tributary confluence, 
etc.) nearest the uppermost records within second or third order 
streams through their confluence with third and fourth order streams 
downstream to an identifiable landmark near the lowermost areas of 
collection in the Pascagoula River (i.e., forks of the East and West 
Pascagoula River). Within the current range of the pearl darter within 
the Pascagoula River drainage, some habitats may or may not be actively 
used at all times by individuals; however, these areas are necessary 
for maintaining population connectivity as well as other physical or 
biological features essential to the conservation of the species and, 
therefore, are considered the geographic area occupied at the time of 
listing for the pearl darter. This area (referred to below as Unit 1: 
Pascagoula River Unit) contains all of the physical or biological 
features essential to the conservation of the pearl darter but may 
require special management conditions or protections.

Areas Unoccupied at the Time of Listing

    To consider areas not occupied by the species at the time of 
listing for designation, we must demonstrate that these areas are 
essential for the conservation of the pearl darter. The occupied 
critical habitat designation does not include geographic areas within 
the Pearl River drainage--the only other area in which the pearl darter 
historically occurred--as it is considered extirpated in that drainage. 
In addition, because the Pascagoula River drainage population is the 
only extant population, that population provides no redundancy for the 
species. Based upon the species' rapid and system-wide extirpation from 
the Pearl River drainage, a series of back-to-back stochastic events or 
a single catastrophic event could similarly significantly reduce 
resiliency or extirpate the Pascagoula River population. For these 
reasons, we determined that we cannot conserve the species by 
designating only occupied habitat as it includes only a single 
population in a single drainage. Thus, we determined that habitat in 
another historical drainage is needed for the long-term survival and 
recovery of the species. Therefore, because we determined that the one 
occupied area alone is not adequate for the conservation of the 
species, we have identified and are designating as critical habitat 
specific areas outside the geographical area occupied by the species at 
the time of listing that are essential for the conservation of the 
species. We used historical occurrence data and the physical or 
biological features described earlier to identify unoccupied habitat 
essential for the conservation of the pearl darter.
    Based on our review, we determined that the lower Strong River, a 
major tributary of the Pearl River, has the potential for future 
reintroduction and reoccupation by the pearl darter provided that 
stressors are managed and mitigated. Reestablishing a population in the 
Strong River will restore the species' redundancy within the historical 
range and increase the species' ecological representation. The specific 
area of the lower Strong River encompasses the minimum area of the 
species' historical range within the Pearl River drainage while still 
providing ecological diversity so that the species can evolve and adapt 
over time. This river reach also provides the potential for the pearl 
darter to expand its range into other historically occupied areas that 
currently may be or may later become suitable to ensure that the

[[Page 20420]]

species has an adequate level of redundancy within the Pearl River 
drainage and guard against future catastrophic events. The lower Strong 
River also represents the stream reach within the historical range with 
the best potential for reestablishment of a population in the Pearl 
River due to current conditions, suitability for reintroductions, and 
access for monitoring.
    Accordingly, we are designating one unoccupied unit in the lower 
Strong River within the Pearl River drainage. As described below in the 
individual unit descriptions (see description for Unit 2: Strong River 
Unit below), this unit contains some of the physical or biological 
features essential to the conservation of the species and is reasonably 
certain to contribute to the conservation of the species.

General Information on the Maps of the Critical Habitat Designation

    The areas designated as critical habitat include only stream 
channels within the ordinary high-water line. There are no developed 
areas within the critical habitat boundaries except for transportation 
and pipeline crossings, which do not remove the suitability of these 
areas for the pearl darter. When determining 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 
pearl darter. 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 rule 
have been excluded by text in the rule and are not designated as 
critical habitat. Therefore, a Federal action involving these lands 
will 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 designating as critical habitat areas that we have 
determined are occupied at the time of listing (i.e., currently 
occupied) and that contain one or more of the physical or biological 
features that are essential to support life-history processes of the 
species. We have determined that occupied areas are inadequate to 
ensure the conservation of the species. Therefore, we are designating 
additional areas as unoccupied critical habitat. We have determined 
that these units are habitat for the species and will both contribute 
to the conservation of the species and contain at least one physical or 
biological features essential to the conservation of the species (see 
description for Unit 2: Strong River Unit below for explanation).
    The two units are designated based on one or more of the physical 
or biological features being present to support pearl darter's life-
history processes. One unit contains all of the identified physical or 
biological features and supports multiple life-history processes. The 
other unit contains only some of the physical or biological features 
necessary to support the pearl darter's particular use of that habitat.
    The critical habitat designation is defined by the map or maps, as 
modified by any accompanying regulatory text, presented at the end of 
this document under Regulation Promulgation. 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 
https://www.regulations.gov at Docket No. FWS-R4-ES-2020-0062, on our 
internet site https://fws.gov/office/mississippi-ecological-services, 
and at the field office responsible for the designation (see FOR 
FURTHER INFORMATION CONTACT).

Final Critical Habitat Designation

    We are designating approximately 524 river mi (843 river km) in two 
units as critical habitat for pearl darter. The critical habitat areas 
we describe below constitute our current best assessment of areas that 
meet the definition of critical habitat for pearl darter. The two areas 
designated as critical habitat are: (1) Pascagoula River Unit and (2) 
Strong River Unit. Table 1 shows the critical habitat units and the 
approximate area of each unit.

                                Table of Critical Habitat Units for Pearl Darter
            [Unit length estimates include only stream channels within the ordinary high-water line]
----------------------------------------------------------------------------------------------------------------
                                                            Riparian land ownership
                              ----------------------------------------------------------------------------------
             Unit                                Federal mi    State mi    County mi   Private mi     Total mi
                                   Occupancy        (km)         (km)        (km)         (km)          (km)
----------------------------------------------------------------------------------------------------------------
1. Pascagoula River..........  Occupied........   * 45 (72)   * 76 (122)  ..........     380 (611)   * 494 (794)
2. Strong River..............  Unoccupied......  ..........  ...........   0.4 (0.6)     30 (48.4)       30 (49)
                                                ----------------------------------------------------------------
    Total mi (km)............  ................   * 45 (72)   * 76 (122)   0.4 (0.6)   410 (659.4)   * 524 (843)
----------------------------------------------------------------------------------------------------------------
* 7 mi (11 km) of pearl darter critical habitat stream miles shared between State and Federal lands.
Note: Area sizes may not sum due to rounding.

    We present brief descriptions of all units, and reasons why they 
meet the definition of critical habitat for pearl darter, below.

Unit 1: Pascagoula River Unit

    Unit 1 consists of 494 river mi (794 river km) of occupied 
connected river and stream channels within the Pascagoula River 
drainage in Mississippi, including:
     63 mi (102 km) of the Pascagoula River channel from its 
confluence with the West Pascagoula River in Jackson County, upstream 
to the confluence of the Leaf and Chickasawhay Rivers in George County;
     80 mi (129 km) of Big Black Creek/Black Creek channel from 
its confluence with the Pascagoula River in Jackson County, upstream to 
U.S. Highway 49 Bridge in Forrest County;
     160 mi (257 km) of Chickasawhay River channel from its 
confluence with the Leaf River just north of Enterprise, Clarke County, 
upstream to the confluence of Okatibbee Creek and Chunky River in 
Clarke County;
     28 mi (45 km) of Chunky River channel from its confluence 
with Okatibbee Creek in Clarke County, upstream to the third (most 
upstream)

[[Page 20421]]

Highway 80 Crossing in Newton County;
     119 mi (192 km) of Leaf River channel from its confluence 
with the Chickasawhay River in George County, upstream to the bridge 
crossing at U.S. Highway 84 in Covington County;
     15 mi (24 km) of Bouie River channel from its confluence 
with the Leaf River, upstream to the confluence of Okatoma Creek in 
Forrest County; and
     28 mi (45 km) of Okatoma Creek from its confluence with 
the Bouie River in Forrest County, upstream to the bridge crossing at 
U.S. Highway 84 in Covington County.
    The riparian lands (channel borders) in this unit are generally 
privately owned agricultural or silvicultural lands with short reaches 
owned and managed by the U.S. Forest Service or the State (see table 
above). All channel segments in Unit 1 are occupied by the pearl 
darter, and the unit contains all the physical or biological features 
essential to the conservation of the species, including deep pools, 
runs, and bends and scour holes; mixtures of bottom substrates of fine 
and coarse sand, silt, loose clay, coarse gravel, fine and coarse 
particulate organic matter, and woody debris; a natural hydrograph with 
flows and water quality that currently support the normal life stages 
of the pearl darter; and the species' prey sources.
    Special management considerations and protections that may be 
required to address threats within the unit include minimizing surface 
water withdrawals or other actions that alter stream flow; reducing 
excessive use of manures, fertilizers, and pesticides near stream 
channels; improving treatment of wastewater discharged from permitted 
facilities; and implementing practices that protect or restore riparian 
buffer areas along stream corridors.

Unit 2: Strong River Unit

    Unit 2 consists of 30 river mi (49 river km) of unoccupied habitat 
in the Strong River channel from its confluence with the Pearl River, 
upstream to U.S. Highway 49, in Simpson County, Mississippi. The 
riparian lands in this unit are generally privately owned agricultural 
or silvicultural lands with a short channel reach (0.39 mi (0.63 km)) 
owned and operated by the Simpson County Park Commission (see table 
above). Unit 2 is not within the geographic range occupied by the pearl 
darter at the time of listing, but this area was historically known to 
provide spawning and recruitment habitat prior to the species' 
extirpation from the Pearl River drainage. This unit currently provides 
some of the physical or biological features essential to the 
conservation of the pearl darter, including a stable channel with 
bottom substrates of fine and coarse sand, silt, loose clay, coarse 
gravel, fine and coarse particulate organic matter, and woody debris; a 
natural hydrograph with flows to support the normal life stages of the 
pearl darter; and the species' prey sources. Further evidence of the 
presence of physical or biological features within this reach of the 
Strong River is demonstrated by recent increases in other benthic fish 
species (e.g., frecklebelly madtom) that declined concurrent with the 
extirpation of the pearl darter (Piller et al. 2004, pp. 1007-1011; 
Wagner et al. 2018, pp. 4-5).
    As described above, the best available information demonstrates 
that the pearl darter disappeared from the entire Pearl River and all 
known tributary segments virtually simultaneously. Therefore, it is 
possible that a series of back-to-back stochastic events or a single 
catastrophic event could significantly reduce or extirpate the 
surviving pearl darter population within the Pascagoula River drainage. 
Due to the species' lack of redundancy, its naturally small numbers 
within the Pascagoula River drainage, and its short life span, the 
pearl darter is more vulnerable to existing and future threats, 
including habitat degradation and loss, catastrophic weather events, 
and introduced species. This unit would serve to protect habitat needed 
to reestablish a wild population within the historical range in the 
Pearl River drainage and recover the species. Reestablishing a 
population of the pearl darter within Unit 2 also would increase the 
species' redundancy and restore ecological representation, better 
ensuring its survival if a stochastic event were to impact the 
Pascagoula River population. This unit is essential for the 
conservation of the species because it will provide habitat for range 
expansion in known historical habitat that is necessary to increase 
viability of the pearl darter by increasing its resiliency, redundancy, 
and representation.
    The need for reintroduction of the pearl darter into the Pearl 
River drainage has been recognized and is being discussed by our 
conservation partners. The landowner of the type locality (location 
where the species was described) within the Strong River unit has been 
working with the Service and MDWFP to regularly monitor for the 
presence of the pearl darter and other benthic fish and expressed 
interest in reestablishing the species on the property. Methods and 
facilities for propagating the species have been developed, tested, and 
proven at a Service fish hatchery. Accordingly, we are reasonably 
certain this unit will contribute to the conservation of the pearl 
darter.

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.
    We published a final rule revising the 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.
    Compliance with the requirements of section 7(a)(2) is documented 
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

[[Page 20422]]

likelihood of jeopardy and/or destruction or adverse modification of 
critical habitat. We define ``reasonable and prudent alternatives'' (at 
50 CFR 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 Service 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 set forth requirements for 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: (a) if the amount or extent of 
taking specified in the incidental take statement is exceeded; (b) if 
new information reveals effects of the action that may affect listed 
species or critical habitat in a manner or to an extent not previously 
considered; (c) if the identified action is subsequently modified in a 
manner that causes an effect to the listed species or critical habitat 
that was not considered in the biological opinion; or (d) if a new 
species is listed or critical habitat designated that may be affected 
by the identified action.
    In such situations, Federal agencies sometimes may need to request 
reinitiation of consultation with us, but Congress also enacted some 
exceptions in 2018 to the requirement to reinitiate consultation on 
certain land management plans on the basis of a new species listing or 
new designation of critical habitat that may be affected by the subject 
Federal action. See 2018 Consolidated Appropriations Act, Public Law 
115-141, Div, O, 132 Stat. 1059 (2018).

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 section 
7(a)(2) of the Act by destroying or adversely modifying such habitat, 
or that may be affected by such designation.
    Activities that we may, during a consultation under section 7(a)(2) 
of the Act, consider likely to destroy or adversely modify critical 
habitat include, but are not limited to:
    (1) Actions that would block or disconnect stream and river 
channels. Such activities could include, but are not limited to, the 
construction of dams or weirs, channelization, and mining. These 
activities could result in destruction of habitat, block movements 
between seasonal habitats, fragment and isolate subpopulations within 
critical habitat units, and/or affect flows within or into critical 
habitat.
    (2) Actions that would affect channel substrates and stability. 
Such activities include channelization, impoundment, mining, road and 
bridge construction, removal of riparian vegetation, and land clearing 
within or into critical habitat. These activities may lead to changes 
in channel substrates, erosion of the streambed and banks, and 
excessive sedimentation that could degrade pearl darter habitat.
    (3) Actions that would reduce flow levels or alter flow regimes 
within or into critical habitat. These could include, but are not 
limited to, activities that block or lower surface flow or groundwater 
levels, including channelization, impoundment, groundwater pumping, and 
surface water withdrawal or diversion. Such activities can result in 
long-term changes in stream flows that affect habitat quality and 
quantity for the darter and its prey.
    (4) Actions that would affect water chemistry or temperature or 
introduce pollutants and nutrients at levels above State of Mississippi 
criteria. Such activities include, but are not limited to, the release 
of chemical pollutants, 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 quality conditions to levels that are beyond the tolerances of 
the pearl darter or its prey species.
    (5) Actions that would result in the introduction, spread, or 
augmentation of nonnative aquatic species in occupied stream segments 
or in stream segments that are hydrologically connected to occupied 
stream segments, even if those segments are occasionally intermittent, 
or in the introduction of other species that compete with or prey on 
the pearl darter. Possible actions could include, but are not limited 
to, stocking of non-native fishes or other related actions. These 
activities also can introduce parasites or disease or affect the 
growth, reproduction, and survival of the pearl darter.

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 geographical areas owned or controlled by the Department 
of Defense (DoD), or designated for its use, that are subject to an 
integrated natural resources management plan (INRMP) prepared under 
section 101 of the Sikes Act Improvement Act of 1997 (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 DoD lands with a completed INRMP within the 
final 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 based on economic 
impacts, impacts on national security, or any other relevant impacts. 
Exclusion decisions are governed by the regulations at 50 CFR 424.19 
and the Policy Regarding Implementation of Section 4(b)(2) of the 
Endangered

[[Page 20423]]

Species Act, 81 FR 7226 (Feb. 11, 2016) (2016 Policy)--both of which 
were developed jointly with the National Marine Fisheries Service 
(NMFS). We also refer to a 2008 Department of the Interior Solicitor's 
opinion entitled ``The Secretary's Authority to Exclude Areas from a 
Critical Habitat Designation under Section 4(b)(2) of the Endangered 
Species Act'' (M-37016). We explain each decision to exclude areas, as 
well as decisions not to exclude, to demonstrate that the decision is 
reasonable.
    The Secretary may exclude any particular area if she determines 
that the benefits of such exclusion outweigh the benefits of including 
such area as part of the critical habitat, unless she 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 the determination to exclude a particular area, 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.

Exclusions Based on 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. In order to consider economic impacts, we prepared 
an incremental effects memorandum (IEM) and screening analysis which, 
together with our narrative and interpretation of effects, we consider 
our economic analysis of the critical habitat designation and related 
factors (IEc 2020, entire; IEc 2021, entire). The analysis, dated July 
13, 2020, was made available for public review from July 13, 2021, 
through September 13, 2021 (IEc 2020, entire). The economic analysis 
addressed probable economic impacts of critical habitat designation for 
the pearl darter. Following the close of the comment period, we 
reviewed and evaluated all information submitted during the comment 
period that may pertain to our consideration of the probable 
incremental economic impacts of this critical habitat designation. 
Additional information relevant to the probable incremental economic 
impacts of the critical habitat designation for the pearl darter is 
summarized below and available in the screening analysis for the pearl 
darter (IEc 2020, entire; IEc 2021, entire), available at https://www.regulations.gov.
    We received public comment on our draft economic analysis during 
the public comment period and updated the analysis based on public 
comments. The economic analysis now considers the addition of 6.5 river 
mi (10.5 river km) of critical habitat in the Chunky River. Because the 
initial assessment considered economic impacts across the entire 
Pascagoula River basin and the additional river segment falls within 
the boundary of this watershed, the updates made to the economic 
analysis did not change the overall conclusions of the analysis.
    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 pearl darter, first we 
identified in the IEM dated April 21, 2020, probable incremental 
economic impacts associated with the following categories of 
activities: (1) roadway and bridge construction and repair; (2) 
commercial or residential development; (3) dredging; (4) groundwater 
pumping; (5) instream dams and diversions; (6) storage, distribution, 
or discharge of chemical pollutants; (7) oil and gas; (8) utilities; 
(9) water quantity and supply; and (10) water quality. 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 Act, designation of critical habitat 
only affects activities conducted, funded, permitted, or authorized by 
Federal agencies. In areas where the pearl darter 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.
    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 pearl 
darter's critical habitat. 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 pearl darter also would 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 designation 
of critical habitat.
    The critical habitat designation for the pearl darter totals 
approximately 524 mi (843 km) of river and stream channels in two 
units. Riparian lands bordering the critical habitat are under private 
(78 percent), county (0.1 percent), State (15 percent), and Federal (9 
percent) ownership. A small portion (1.3 percent) has shared State and 
Federal ownership. Unit 1 is occupied by the pearl darter and 
represents 94 percent of the proposed critical habitat. Within this 
occupied unit, 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 pearl 
darter. Therefore, only administrative costs are expected in actions 
affecting this unit. While this additional analysis will require time 
and resources by both the Federal action agency and the Service, it is 
believed that, in most circumstances, these costs would not be 
significant because they are predominantly administrative in nature.
    Unit 2 is currently unoccupied by the species but is essential for 
the conservation of the species. This unit totals 30 mi (49 km) of 
river and stream channels and comprises 6 percent of the total proposed 
critical habitat designation. In this unoccupied area, any conservation 
efforts or associated probable impacts would be considered incremental 
effects attributed to the critical habitat designation. However, two 
threatened species, Gulf sturgeon and ringed map turtle currently 
occupy this unit. Conservation efforts to protect these species also 
would protect pearl darter critical habitat.
    The economic analysis finds that the total annual incremental costs 
of critical habitat designation for the pearl darter are not 
anticipated to reach $100 million in any given year based on the 
anticipated annual number of consultations and associated 
administrative costs, which are not

[[Page 20424]]

expected to exceed $710,000 in any year.
    In Unit 1, which constitutes 94 percent of the critical habitat 
area, the activities that may affect the critical habitat are already 
subject to section 7 consultation due to the presence of pearl darter. 
We determined that the project modification recommendations made to 
avoid jeopardy to the pearl darter also would result in the avoidance 
of adverse modification. Thus, for projects and activities occurring in 
Unit 1, no additional project modification recommendations are likely 
to result from this critical habitat rule and costs would be limited to 
additional administrative effort.
    A relatively small fraction (6 percent) of the critical habitat 
designation is in Unit 2, which is not currently occupied by the 
species. In these areas, activities that may affect the critical 
habitat for the pearl darter are also already subject to section 7 
consultation due to the presence of other listed species (Gulf sturgeon 
and ringed map turtle) with similar habitat requirements. Additionally, 
activities that may affect pearl darter critical habitat in Unit 2 
generally implement project modification recommendations from a 
standardized set provided in the Mississippi Standard Local Operations 
Procedures for Endangered Species (SLOPES) agreement. Through this 
agreement that was entered into in June 2017, the U.S. Army Corps of 
Engineers (COE) and the Service have established routine procedures for 
jointly implementing section 7 requirements for all projects that 
require COE permits. The agreement requires the COE to consult species-
specific SLOPES documents to determine if a project is expected to 
adversely affect the species or its habitat. As part of the agreement, 
species-specific avoidance and minimization measures have been 
established for COE projects. The measures described for the pearl 
darter are similar to the measures described for overlapping species. 
Because the COE addresses permitting for projects with water impacts, 
all projects with a Federal nexus in the pearl darter critical habitat 
are likely to follow the Mississippi SLOPES procedures and 
recommendations. Therefore, even absent critical habitat designation, 
these activities are likely to avoid adverse effects on the habitat.
    As discussed above, we considered the economic impacts of the 
critical habitat designation, and the Secretary is not exercising her 
discretion to exclude any areas from this designation of critical 
habitat for the pearl darter based on economic impacts.

Exclusions Based on Impacts on National Security and Homeland Security

    In preparing this rule, we have determined that there are no lands 
within the designated critical habitat for pearl darter that are owned 
or managed by the DoD or Department of Homeland Security, and, 
therefore, we anticipate no impact on national security or homeland 
security. We did not receive any additional information during the 
public comment period for the proposed designation regarding impacts of 
the designation on national security or homeland security that would 
support excluding any specific areas from the final critical habitat 
designation under authority of section 4(b)(2) and our implementing 
regulations at 50 CFR 424.19, as well as the 2016 Policy.

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 as discussed above. To identify other relevant impacts that 
may affect the exclusion analysis, we consider a number of factors, 
including whether there are permitted conservation plans covering the 
species in the area such as HCPs, safe harbor agreements (SHAs), or 
candidate conservation agreements with assurances (CCAAs), or whether 
there are non-permitted conservation agreements and partnerships that 
would be encouraged by designation of, or exclusion from, critical 
habitat. In addition, we look at whether Tribal conservation plans or 
partnerships, Tribal resources, or government-to-government 
relationships of the United States with Tribal entities may be affected 
by the designation. We also consider any State, local, social, or other 
impacts that might occur because of the designation.
    We are not excluding any areas from critical habitat. In preparing 
this final rule, we have determined that there are currently no HCPs or 
other management plans for the pearl darter, and the designation does 
not include any Tribal lands or trust resources. We anticipate no 
impact on Tribal lands, partnerships, or HCPs from this final critical 
habitat designation. We did not receive any information during the 
public comment period for the proposed rule regarding other relevant 
impacts to support excluding any specific areas from the final critical 
habitat designation under the authority of section 4(b)(2) and our 
implementing regulations at 50 CFR 424.19, as well as the 2016 Policy. 
Accordingly, the Secretary is not exercising her discretion to exclude 
any areas from this final designation based on other relevant impacts.

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 proposed 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,

[[Page 20425]]

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.
    Under the RFA, as amended, and following recent court decisions, 
Federal agencies are required to evaluate the potential incremental 
impacts of rulemaking on those entities directly regulated by the 
rulemaking itself; in other words, the RFA does not require agencies 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 
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 
will be directly regulated by this rulemaking, we certify that this 
critical habitat designation will not have a significant economic 
impact on a substantial number of small entities.
    During the development of this final rule, we reviewed and 
evaluated all information submitted during the comment period on the 
July 13, 2021, proposed rule (86 FR 36678) that may pertain to our 
consideration of the probable incremental economic impacts of this 
critical habitat designation. Based on this information, we affirm our 
certification that this critical habitat designation will not have a 
significant economic impact on a substantial number of small entities, 
and a 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. In our economic analysis, we did not find that this 
critical habitat designation 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 finding:
    (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 are not likely to destroy or adversely modify 
critical habitat under section 7. 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. 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 it will not produce a Federal mandate 
of $100 million or greater in any year, that is, it is not a 
``significant regulatory action'' under the Unfunded Mandates Reform 
Act. The designation of critical habitat imposes no obligations on 
State or local governments. 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 pearl darter in a takings implications assessment. The 
Act does not authorize us 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

[[Page 20426]]

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 the pearl darter 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 rule does not have 
significant federalism effects. A federalism summary impact statement 
is not required. In keeping with Department of the Interior and 
Department of Commerce policy, we requested information from, and 
coordinated development of this critical habitat designation with, 
appropriate State resource agencies. 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 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 for 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 
State and local governments in long-range planning because they 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) of the Act will 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 will not 
unduly burden the judicial system and that it meets the requirements of 
sections 3(a) and 3(b)(2) of the Order. We are designating critical 
habitat in accordance with the provisions of the Act. To assist the 
public in understanding the habitat needs of the species, this final 
rule identifies the 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 information collection requirements, and 
a submission to the Office of Management and Budget (OMB) under the 
Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.) is not 
required. We may not conduct or sponsor and you are 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.)

    Regulations adopted pursuant to section 4(a) of the Act are exempt 
from the National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et 
seq.) and do not require an environmental analysis under NEPA. We 
published a notice outlining our reasons for this determination in the 
Federal Register on October 25, 1983 (48 FR 49244). This includes 
listing, delisting, and reclassification rules, as well as critical 
habitat designations and species-specific protective regulations 
promulgated concurrently with a decision to list or reclassify a 
species as threatened. The courts have upheld this position (e.g., 
Douglas County v. Babbitt, 48 F.3d 1495 (9th Cir. 1995) (critical 
habitat); Center for Biological Diversity v. U.S. Fish and Wildlife 
Service., 2005 WL 2000928 (N.D. Cal. Aug. 19, 2005) (concurrent 4(d) 
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 federally recognized 
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. We have determined that no Tribal 
interests fall within the boundaries of the final critical habitat for 
the pearl darter, so no Tribal lands will be affected by the 
designation.

References Cited

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

Authors

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

List of Subjects in 50 CFR Part 17

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

Regulation Promulgation

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

PART 17--ENDANGERED AND THREATENED WILDLIFE AND PLANTS

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

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


0
2. In Sec.  17.11, in paragraph (h), amend the List of Endangered and 
Threatened Wildlife by revising the entry for ``Darter, pearl'' under 
Fishes to read as follows:

[[Page 20427]]

Sec.  17.11  Endangered and threatened wildlife.

* * * * *
    (h) * * *

----------------------------------------------------------------------------------------------------------------
                                                                                              Listing citations
           Common name               Scientific name        Where listed         Status         and applicable
                                                                                                    rules
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                                                     Fishes
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Darter, pearl....................  Percina aurora.....  Wherever found.....  T               82 FR 43885, 9/20/
                                                                                              2017; 50 CFR
                                                                                              17.95(e).\CH\
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------


0
3. In Sec.  17.95, amend paragraph (e) by adding an entry for ``Pearl 
Darter (Percina aurora)'' following the entry for ``Niangua Darter 
(Etheostoma nianguae)'' to read as follows:


Sec.  17.95  Critical habitat--fish and wildlife.

* * * * *
    (e) Fishes.
* * * * *
Pearl Darter (Percina aurora)
    (1) Critical habitat units are depicted for Clark, Covington, 
Forrest, George, Greene, Jackson, Jones, Lauderdale, Newton, Perry, 
Simpson, Stone, and Wayne Counties, Mississippi, on the maps in this 
entry.
    (2) Within these areas, the physical or biological features 
essential to the conservation of pearl darter consist of the following 
components:
    (i) Unobstructed and stable stream and river channels with:
    (A) Connected sequences of channel runs and bends associated with 
pools and scour holes; and
    (B) Bottom substrates consisting of fine and coarse sand, silt, 
loose clay, coarse gravel, fine and coarse particulate organic matter, 
or woody debris.
    (ii) A natural flow regime necessary to maintain instream habitats 
and their connectivity.
    (iii) Water quality conditions, including cool to warm water 
temperatures (8 to 30 [deg]C (46.4 to 86.0 [deg]F)), high dissolved 
oxygen (5.8 to 9.3 mg/l), slightly acidic to basic pH (6.3 to 7.6), and 
low levels of pollutants and nutrients meeting the current State of 
Mississippi criteria, as necessary to maintain natural physiological 
processes for normal behavior, growth, and viability of all life stages 
of the species.
    (iv) Presence of a prey base of small aquatic macroinvertebrates, 
including larval mayflies, larval caddisflies, larval black flies, 
ostracods (crustaceans), chironomids (midges), and gastropods (snails).
    (3) Critical habitat includes only the stream channels within the 
ordinary high water line and 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 
May 8, 2023.
    (4) Data layers defining map units were created using U.S. 
Geological Survey's National Hydrography Dataset flowline data on a 
base map of State and County boundaries from the U.S. Department of 
Agriculture's Natural Resources Conservation Service. Critical habitat 
units were mapped using the Geographic Coordinate System North American 
1983 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 at https://fws.gov/office/mississippi-ecological-services, at 
https://www.regulations.gov at Docket No. FWS-R4-ES-2020-0062, 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) Index map follows:
BILLING CODE 4333-15-P
Figure 1 to Pearl Darter (Percina aurora) paragraph (5)


[[Page 20428]]


[GRAPHIC] [TIFF OMITTED] TR06AP23.007

    (6) Unit 1: Pascagoula River drainage, Clarke, Covington, Forrest, 
George, Greene, Lauderdale, Jackson, Jones, Newton, Perry, Stone, and 
Wayne Counties, Mississippi.
    (i) Unit 1 consists of 494 river miles (mi) (794 river kilometers 
(km)) of connected river and stream channels within the Pascagoula 
River drainage, including:
    (A) The Pascagoula River from its confluence with the West 
Pascagoula River in Jackson County, upstream 63 mi (102 km) to the 
confluence of the Leaf and Chickasawhay Rivers in George County;
    (B) The Big Black/Black Creek from its confluence with the 
Pascagoula River in Jackson County, upstream 80 mi (129 km) to U.S. 
Highway 49 Bridge in Forrest County;
    (C) The Chickasawhay River from its confluence with the Leaf River 
just north of Enterprise, Clarke County, upstream 160 mi (257 km) to 
the confluence of Okatibbee Creek and Chunky River in Clarke County;
    (D) The Chunky River from its confluence with Okatibbee Creek in 
Clarke County, upstream 28 mi (45 km) to the third (most upstream) 
Highway 80 Crossing in Newton County;

[[Page 20429]]

    (E) The Leaf River from its confluence with the Chickasawhay River 
in George County, upstream 119 mi (192 km) to the bridge crossing at 
U.S. Highway 84 in Covington County;
    (F) The Bouie River from its confluence with the Leaf River, 
upstream 15 mi (24 km) to the confluence of Okatoma Creek, in Forrest 
County; and
    (G) The Okatoma Creek from its confluence with the Bouie River in 
Forrest County, upstream 28 mi (45 km) to the bridge crossing at U.S. 
Highway 84 in Covington County.
    (ii) The channel borders (and therefore the stream channel bottoms) 
in Unit 1 are generally privately owned agricultural or silvicultural 
lands with the exception of 76 mi (122 km) of the Pascagoula River 
channel border owned and managed by the Mississippi Department of 
Wildlife, Fisheries, and Parks, and 45 mi (72 km) owned by the U.S. 
Forest Service.
    (iii) Map of Unit 1 follows:

Figure 2 to Pearl Darter (Percina aurora) paragraph (6)(iii)
[GRAPHIC] [TIFF OMITTED] TR06AP23.008


[[Page 20430]]


    (7) Unit 2: Strong River, Simpson County, Mississippi.
    (i) Unit 2 consists of approximately 30 mi (49 km) of the Strong 
River channel from its confluence with the Pearl River, upstream to 
U.S. Highway 49 in Simpson County.
    (ii) The channel borders (and therefore the stream channel bottoms) 
in this unit are generally privately owned agricultural or 
silvicultural lands with the exception of a short channel reach (0.39 
mi (0.63 km)) owned and managed by the Simpson County Park Commission.
    (iii) Map of Unit 2 follows:

Figure 3 to Pearl Darter (Percina aurora) paragraph (7)(iii)
[GRAPHIC] [TIFF OMITTED] TR06AP23.009

* * * * *

Martha Williams,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2023-07081 Filed 4-5-23; 8:45 am]
BILLING CODE 4333-15-C