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Proposed Rule2023-20296

Endangered and Threatened Wildlife and Plants; One Species Not Warranted for Delisting and Six Species Not Warranted for Listing as Endangered or Threatened Species

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Published

September 20, 2023

Issuing agencies

Interior DepartmentFish and Wildlife Service

Abstract

We, the U.S. Fish and Wildlife Service (Service), announce findings that one species is not warranted for delisting and six species are not warranted for listing as endangered or threatened species under the Endangered Species Act of 1973, as amended (Act). After a thorough review of the best available scientific and commercial information, we find that it is not warranted at this time to delist the southern sea otter (Enhydra lutris nereis). We also find that is not warranted at this time to list the Cascades frog (Rana cascadae), plains spotted skunk (Spilogale interrupta, formerly recognized as one of three subspecies of eastern spotted skunk (Spilogale putorius interrupta)), sicklefin chub (Macrhybopsis meeki), sturgeon chub (Macrhybopsis gelida), Tennessee cave salamander (Gyrinophilus palleucus), and Yazoo crayfish (Faxonius hartfieldi, formerly Orconectes hartfieldi). However, we ask the public to submit to us at any time any new information relevant to the status of any of the species mentioned above or their habitats.

Full Text

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<title>Federal Register, Volume 88 Issue 181 (Wednesday, September 20, 2023)</title>
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[Federal Register Volume 88, Number 181 (Wednesday, September 20, 2023)]
[Proposed Rules]
[Pages 64870-64880]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-20296]

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DEPARTMENT OF THE INTERIOR

Fish and Wildlife Service

50 CFR Part 17

[FF09E21000 FXES1111090FEDR 234]

Endangered and Threatened Wildlife and Plants; One Species Not
Warranted for Delisting and Six Species Not Warranted for Listing as
Endangered or Threatened Species

AGENCY: Fish and Wildlife Service, Interior.

ACTION: Notification of findings.

-----------------------------------------------------------------------

SUMMARY: We, the U.S. Fish and Wildlife Service (Service), announce
findings that one species is not warranted for delisting and six
species are not warranted for listing as endangered or threatened
species under the Endangered Species Act of 1973, as amended (Act).
After a thorough review of the best available scientific and commercial
information, we find that it is not warranted at this time to delist
the southern sea otter (Enhydra lutris nereis). We also find that is
not warranted at this time to list the Cascades frog (Rana cascadae),
plains spotted skunk (Spilogale interrupta, formerly recognized as one
of three subspecies of eastern spotted skunk (Spilogale putorius
interrupta)), sicklefin chub (Macrhybopsis meeki), sturgeon chub
(Macrhybopsis gelida), Tennessee cave salamander (Gyrinophilus
palleucus), and Yazoo crayfish (Faxonius hartfieldi, formerly
Orconectes hartfieldi). However, we ask the public to submit to us at
any time any new information relevant to the status of any of the
species mentioned above or their habitats.

DATES: The findings in this document were made on September 20, 2023.

ADDRESSES: Detailed descriptions of the bases for these findings are
available on the internet at <a href="https://www.regulations.gov">https://www.regulations.gov</a> under the
following docket numbers:

------------------------------------------------------------------------
Species Docket No.
------------------------------------------------------------------------
Cascades frog....................... FWS-R1-ES-2023-0127.
Plains spotted skunk................ FWS-R3-ES-2023-0128.
Sicklefin chub...................... FWS-R6-ES-2023-0130.
Southern sea otter.................. FWS-R8-ES-2023-0132.
Sturgeon chub....................... FWS-R6-ES-2023-0131.
Tennessee cave salamander........... FWS-R4-ES-2023-0133.
Yazoo crayfish...................... FWS-R4-ES-2023-0134.
------------------------------------------------------------------------

Those descriptions are also available by contacting the appropriate
person as specified under FOR FURTHER INFORMATION CONTACT. Please
submit any new information, materials, comments, or questions
concerning this finding to the appropriate person, as specified under
FOR FURTHER INFORMATION CONTACT.

FOR FURTHER INFORMATION CONTACT:

------------------------------------------------------------------------
Species Contact information
------------------------------------------------------------------------
Cascades frog..................... Jeff Dillon, Endangered Species
Division Manager, Oregon Fish and
Wildlife Office,
<a href="/cdn-cgi/l/email-protection#0a606f6c6c786f73556e63666665644a6c7d79246d657c">[email&#160;protected]</a>, 503-231-
6179.
Plains spotted skunk.............. John Weber, Field Supervisor,
Missouri Field Office,
<a href="/cdn-cgi/l/email-protection#672d080f0938343830020502152701101449000811">[email&#160;protected]</a>, 573-825-6048.

[[Page 64871]]

Sicklefin chub and sturgeon chub.. Amity Bass, Field Supervisor, North
and South Dakota Ecological
Services, <a href="/cdn-cgi/l/email-protection#5435393d202d0b36352727143223277a333b22">[email&#160;protected]</a>, 605-
222-0228.
Southern sea otter................ Steve Henry, Field Supervisor,
Ventura Fish and Wildlife Office,
<a href="/cdn-cgi/l/email-protection#3e4d4a5b485b61565b504c477e58494d10595148">[email&#160;protected]</a>, 805-644-1766.
Tennessee cave salamander......... Dan Elbert, Field Supervisor,
Tennessee FO,
<a href="/cdn-cgi/l/email-protection#e98d8887808c85b68c858b8c9b9da98f9e9ac78e869f">[email&#160;protected]</a>, 571-461-
8964.
Yazoo crayfish.................... James Austin, Field Supervisor,
Mississippi Ecological Field
Office, 601-321-1129,
<a href="/cdn-cgi/l/email-protection#c4aea5a9a1b79ba5b1b7b0adaa84a2b3b7eaa3abb2">[email&#160;protected]</a>.
------------------------------------------------------------------------

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

SUPPLEMENTARY INFORMATION:

Background

Under section 4(b)(3)(B) of the Act (16 U.S.C. 1531 et seq.), we
are required to make a finding on whether or not a petitioned action is
warranted within 12 months after receiving any petition that we have
determined contains substantial scientific or commercial information
indicating that the petitioned action may be warranted (hereafter a
``12-month finding''). We must make a finding that the petitioned
action is: (1) Not warranted; (2) warranted; or (3) warranted but
precluded by other listing activity. We must publish a notification of
these 12-month findings in the Federal Register.

Summary of Information Pertaining to the Five Factors

Section 4 of the Act (16 U.S.C. 1533) and the implementing
regulations at part 424 of title 50 of the Code of Federal Regulations
(50 CFR part 424) set forth procedures for adding species to, removing
species from, or reclassifying species on the Lists of Endangered and
Threatened Wildlife and Plants (Lists). The Act defines ``species'' as
including any subspecies of fish or wildlife or plants, and any
distinct population segment of any species of vertebrate fish or
wildlife which interbreeds when mature (16 U.S.C. 1532(16)). The Act
defines ``endangered species'' as any species that is in danger of
extinction throughout all or a significant portion of its range (16
U.S.C. 1532(6)), and ``threatened species'' as any species that is
likely to become an endangered species within the foreseeable future
throughout all or a significant portion of its range (16 U.S.C.
1532(20)). Under section 4(a)(1) of the Act, a species may be
determined to be an endangered species or a threatened species because
of any of the following five factors:
(A) The present or threatened destruction, modification, or
curtailment of its habitat or range;
(B) Overutilization for commercial, recreational, scientific, or
educational purposes;
(C) Disease or predation;
(D) The inadequacy of existing regulatory mechanisms; or
(E) Other natural or manmade factors affecting its continued
existence.
These factors represent broad categories of natural or human-caused
actions or conditions that could have an effect on a species' continued
existence. In evaluating these actions and conditions, we look for
those that may have a negative effect on individuals of the species, as
well as other actions or conditions that may ameliorate any negative
effects or may have positive effects.
We use the term ``threat'' to refer in general to actions or
conditions that are known to or are reasonably likely to negatively
affect individuals of a species. The term ``threat'' includes actions
or conditions that have a direct impact on individuals (direct
impacts), as well as those that affect individuals through alteration
of their habitat or required resources (stressors). The term ``threat''
may encompass--either together or separately--the source of the action
or condition or the action or condition itself. However, the mere
identification of any threat(s) does not necessarily mean that the
species meets the statutory definition of an ``endangered species'' or
a ``threatened species.'' In determining whether a species meets either
definition, we must evaluate all identified threats by considering the
expected response by the species, and the effects of the threats--in
light of those actions and conditions that will ameliorate the
threats--on an individual, population, and species level. We evaluate
each threat and its expected effects on the species, then analyze the
cumulative effect of all of the threats on the species as a whole. We
also consider the cumulative effect of the threats in light of those
actions and conditions that will have positive effects on the species,
such as any existing regulatory mechanisms or conservation efforts. The
Secretary determines whether the species meets the Act's definition of
an ``endangered species'' or a ``threatened species'' only after
conducting this cumulative analysis and describing the expected effect
on the species now and in the foreseeable future.
The Act does not define the term ``foreseeable future,'' which
appears in the statutory definition of ``threatened species.'' Our
implementing regulations at 50 CFR 424.11(d) set forth a framework for
evaluating the foreseeable future on a case-by-case basis. The term
``foreseeable future'' extends only so far into the future as we can
reasonably determine that both the future threats and the species'
responses to those threats are likely. In other words, the foreseeable
future is the period of time in which we can make reliable predictions.
``Reliable'' does not mean ``certain''; it means sufficient to provide
a reasonable degree of confidence in the prediction. Thus, a prediction
is reliable if it is reasonable to depend on it when making decisions.
It is not always possible or necessary to define foreseeable future
as a particular number of years. Analysis of the foreseeable future
uses the best scientific and commercial data available and should
consider the timeframes applicable to the relevant threats and to the
species' responses to those threats in view of its life-history
characteristics. Data that are typically relevant to assessing the
species' biological response include species-specific factors such as
lifespan, reproductive rates or productivity, certain behaviors, and
other demographic factors.
In conducting our evaluation of the five factors provided in
section 4(a)(1) of the Act to determine whether the Cascades frog,
plains spotted skunk, sicklefin chub, southern sea otter, sturgeon
chub, Tennessee cave salamander, and Yazoo crayfish meet the Act's
definition of ``endangered species'' or ``threatened species,'' we
considered and thoroughly evaluated the best scientific and commercial
information available regarding the past, present, and future stressors
and threats. We reviewed the petitions, information available in our
files, and other available published and unpublished

[[Page 64872]]

information for all these species. Our evaluation may include
information from recognized experts; Federal, State, and Tribal
governments; academic institutions; foreign governments; private
entities; and other members of the public.
In accordance with the regulations at 50 CFR 424.14(h)(2)(i), this
document announces the not-warranted findings on petitions to delist
one species and list six species. We have also elected to include brief
summaries of the analyses on which these findings are based. We provide
the full analyses, including the reasons and data on which the findings
are based, in the decisional file for each of the seven actions
included in this document. The following is a description of the
documents containing these analyses:
The species assessment forms for Cascades frog, plains spotted
skunk, sicklefin chub, sturgeon chub, Tennessee cave salamander, and
Yazoo crayfish contain more detailed biological information, a thorough
analysis of the listing factors, a list of literature cited, and an
explanation of why we determined that each species does not meet the
Act's definition of an ``endangered species'' or a ``threatened
species.'' The species assessment form for the southern sea otter
contains more detailed biological information, a thorough analysis of
the listing factors, a list of literature cited, and an explanation of
why we determined that the species continues to meet the Act's
definition of a ``threatened'' species. To inform our status reviews,
we completed species status assessment (SSA) reports for the Cascades
frog, plains spotted skunk, sicklefin chub, southern sea otter,
sturgeon chub, Tennessee cave salamander, and Yazoo crayfish. Each SSA
report contains a thorough review of the taxonomy, life history,
ecology, current status, and projected future status for each species.
This supporting information can be found on the internet at <a href="https://www.regulations.gov">https://www.regulations.gov</a> under the appropriate docket number (see ADDRESSES,
above).

Cascades Frog

Previous Federal Actions
On July 11, 2012, we received a petition from the Center for
Biological Diversity to list 53 amphibian and reptile species,
including Cascades frog (Rana cascadae), as an endangered or threatened
species under the Act. On July 1, 2015, we published a 90-day finding
(80 FR 37568) that the petition contained substantial information
indicating listing may be warranted for the species. This document
constitutes our 12-month finding on the July 11, 2012, petition to list
Cascades frog under the Act.
Summary of Findings
The Cascades frog is a medium-sized frog typically less than 71
millimeters (mm) (2.8 inches (in)) in length; males are smaller than
females. The Cascades frog is greenish brown with variation among frogs
in spot appearance. The species is generally associated with middle to
high elevations (approximately 400 to 2,500 meters (m) (1,312 to 8,202
feet (ft)); its current and historical range extends along the Cascade
Mountain Range from near the United States-Canada border south through
Washington and Oregon to California just south of Lassen Peak. The
species can also be found within the Klamath Mountains of California
and the Olympic Mountains in Washington. The species may be extirpated
within Lassen Volcanic National Park.
The Cascades frog is primarily aquatic, using lakes, ponds, wet
meadows, and streams, where they are often found along shorelines or on
emergent rocks or logs. It uses habitats that are maintained by cold
winters with deep snowpack and spring snowmelt. A diversity of aquatic
features is needed to support all life stages, breeding, foraging, and
dispersal, and to provide areas of refuge from predators. Precipitation
is important in supporting aquatic habitats and movement of individuals
across the landscape. The Cascades frog overwinters in aerobic
sediments at the bottom of aquatic features that have stable thermal
conditions and do not completely freeze over.
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the Cascades frog, and we evaluated all relevant factors under the
five listing factors, including any regulatory mechanisms and
conservation measures addressing these threats. The primary threats
affecting the Cascades frog's biological status include climate change,
the chytrid fungus Batrachochytrium dendrobatidis (Bd), and nonnative
trout.
We separated the species' range into five representative units
(Olympics, Washington Cascades, Oregon Cascades, California North, and
California South) to analyze current and future condition. Our current
condition analysis finds that resiliency of the Cascades frog is
variable across the range, with all representative units having
conditions to support healthy populations. However, the California
units are less resilient than those in Oregon and Washington. The
distribution of healthy (i.e., good to fair resiliency) populations of
the species across a broad geographic range ensures that catastrophic
events such as volcanic eruptions, presence of Bd, and wildfire are not
likely to cause risk of Cascades frog extinction. Further, the Cascades
frog continues to occupy historical sites throughout all representative
units, and factors such as habitat, distribution of occurrences,
connectivity, and natural geological and elevational gaps in the range
all contribute to the species' overall adaptive capacity. Therefore, we
conclude that Cascades frog is not currently in danger of extinction
throughout all of its range and does not meet the Act's definition of
an endangered species.
In considering the foreseeable future as it relates to the status
of the Cascades frog, we considered the relevant risk factors (threats/
stressors) acting on the species and whether we could draw reliable
predictions about the species' response to these factors. Our analysis
in the SSA report of future scenarios over a an approximately 50-year
timeframe encompasses the best available information for future
projections of habitat suitability based on maximum temperature,
minimum temperature, precipitation, snow water equivalent, soil
moisture, and potential evapotranspiration under two different climate
change futures (representative concentration pathways (RCP) 4.5 and
8.5). We determined that this approximately 50-year timeframe enabled
us to consider the threats/stressors acting on the species and draw
reliable predictions about the species' response to these factors.
Based on the 3Rs (resiliency, representation, and redundancy)
analyzed in the SSA report, the Cascades frog is projected to maintain
multiple resilient populations, based on adequate suitable habitat
availability, across the landscape for approximately 50 years into the
future. The species is expected to withstand both stochastic and
catastrophic events and have sufficient adaptive capacity to endure
future climate change. Thus, after assessing the best available
information, we conclude that Cascades frog is not likely to become
endangered within the foreseeable future throughout all of its range.
Having determined that the Cascades frog is not in danger of
extinction or likely to become so in the foreseeable future throughout
all of its range, we considered whether it may be in danger of
extinction or likely to become so in the foreseeable future in a
significant

[[Page 64873]]

portion of its range--that is, whether there is any portion of the
species' range for which it is true that both (1) the portion is
significant; and (2) the species is in danger of extinction now or
likely to become so in the foreseeable future in that portion.
Depending on the case, it might be more efficient for us to address the
``significance'' question or the ``status'' question first. We can
choose to address either question first. Regardless of which question
we address first, if we reach a negative answer with respect to the
first question that we address, we do not need to evaluate the other
question for that portion of the species' range.
We identified the Olympics and California South representative
units as portions that might have a different status than the species
rangewide. We examined the following threats: climate change, Bd, and
nonnative trout, including cumulative effects.
The Olympics representative unit has fewer analysis units (AUs) (6)
than most of the other representative units. However, the largest AU
(unit 15) comprises nearly the entire Olympics representative unit and
contains the majority of the Cascades frogs in that unit. Currently,
this representative unit has populations with sufficient resiliency to
withstand stochastic events, and the well-distributed largest
population, which can be found across nearly the entire representation
unit with good resiliency, is likely to withstand catastrophic events.
We, therefore, determine that the Cascades frog is not in danger of
extinction in the Olympics part of the range.
The Olympics have more snow-fed aquatic systems, indicating that
they could be more sensitive to climate change impacts than habitat in
other parts of the Cascades frog's range. However, these climate
effects depend on the kind of wetland habitat affected, the
distribution of wetland types, and the degree of change in hydrologic
patterns under different future climates. We do not know explicit
linkages of climate effects to specific Cascades frog habitat. Despite
this caveat, our future conditions analysis indicates that the largest
AU (unit 15), which covers the majority of the representation unit,
will maintain fair habitat suitability across all future scenarios.
Further, there does not appear to be widespread adult mortality
consistent with Bd in the Olympics. While nonnative trout are in
wetlands of the Washington Olympics and will likely continue to be a
stressor, there are areas within the Olympics range (e.g., national
parks) where this stressor is not likely to exacerbate any projected
declines. Based on the projected future conditions, we conclude that
the Cascades frog is not in danger of extinction within the foreseeable
future in the Olympics portion of its range.
Populations within the California South representative unit have
experienced declines, local extirpations, and low population viability
due in part to Bd, droughts, nonnative trout stocking, and lack of
connectivity to other habitat. Despite declines in the California South
part of the range, 75 percent of the AUs are currently in fair
condition, indicative of relatively healthy populations. These fair
condition AUs are distributed throughout the representative unit, thus
providing redundancy to both stochastic and catastrophic events. We,
therefore, determine that the Cascades frog is not in danger of
extinction in the California South part of the range.
Our future conditions analysis shows that all AUs within the
California South representation unit either maintain fair habitat
condition or improve to good habitat condition approximately 50 years
into the future. Although habitat suitability is predicted to increase,
the potential for the Cascades frog to colonize suitable habitat is
dependent on the health of source populations, connectivity, and
habitat features to support the species across all life stages, and
there is some uncertainty as to the extent that this could happen in
the future. The projected future distribution of fair/good condition
AUs throughout the California South unit provide redundancy to
stochastic and catastrophic events. Based on this assessment, we
conclude that the Cascades frog is not in danger of extinction within
the foreseeable future in the California South portion of its range.
Because we determined that there are no portions within the species
range that are currently in danger of extinction or likely to become so
in the foreseeable future, we do not need to consider whether any
portion of the range is significant. Nonetheless, we did undertake this
further step for California South as a part of our evaluation of
significant portion of the range. Considerations for significance can
include whether the portion constitutes a large geographic area
relative to the rest of the range, whether the portion constitutes
habitat of high quality relative to the remaining portions of the
range, or whether the portion constitutes high or unique value habitat
for the species. California South is not a large representative unit
relative to the rest of the range. It does not have unique or high
value habitat nor high quality habitat relative to any other habitat
throughout the range, and while the Lassen Mountains are different from
other mountains in the range, they provide similar habitat features for
the frogs, and thus they do not result in a meaningful difference in
the ecology of the species. For these reasons, the California South
portion is not considered significant. Therefore, the California South
portion is not a significant portion of the range.
Thus, after assessing the best available information, we conclude
that the Cascades frog is not in danger of extinction or likely to
become in danger of extinction within the foreseeable future throughout
all of its range or in any significant portion of its range. Therefore,
we find that listing the Cascades frog as an endangered species or
threatened species under the Act is not warranted.
A detailed discussion of the basis for this finding can be found in
the Cascades frog species assessment form and other supporting
documents on <a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket No. FWS-R1-ES-
2023-0127 (see ADDRESSES, above).

Peer Review

In accordance with our July 1, 1994, peer review policy (59 FR
34270; July 1, 1994) and the Service's August 22, 2016, Director's Memo
on the Peer Review Process, we solicited independent scientific reviews
of the information contained in the Cascades frog SSA report. The
Service sent the SSA report to three independent peer reviewers and
received two responses. Results of this structured peer review process
can be found at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. We incorporated the
results of these reviews, as appropriate, into the SSA report, which is
the foundation for this finding.

Plains Spotted Skunk

Previous Federal Actions
On July 18, 2011, we received a petition from Mr. David Wade and
Dr. Thomas Alton, requesting that multiple grassland thicket species or
subspecies be listed as endangered or threatened under the Act,
including the plains spotted skunk (Spilogale interrupta, formerly
recognized as one of three subspecies of eastern spotted skunk
(Spilogale putorius interrupta)). On December 4, 2012, we published a
90-day finding in the Federal Register (77 FR 71759) concluding that
the petition presented substantial scientific or commercial information
indicating that listing the plains spotted skunk may be warranted. This
document constitutes our 12-month finding on the July 18,

[[Page 64874]]

2011, petition to list the plains spotted skunk under the Act.
Summary of Finding
The plains spotted skunk is a small mammal in the weasel family,
most notable for its vivid black and white fur markings, that occurs in
a wide range of habitat types across the Great Plains region of the
contiguous United States. States with current occurrences (observed
from 2000 to the present) include Arkansas, Iowa, Kansas, Minnesota,
Missouri, Nebraska, North Dakota, Oklahoma, South Dakota, Texas, and
Wyoming.
This generalist species exhibits relatively high adaptability
related to its diet and foraging, habitat use, and activity patterns.
The habitat elements that we identified as important to plains spotted
skunk individuals at each life stage include freshwater of sufficient
quantity, food availability, den availability, and habitat complexity
that provides protective cover. Plains spotted skunks are opportunistic
omnivores, whose diet varies across seasons and habitats along with the
availability and abundance of food items. Adult plains spotted skunks
are typically solitary with the exception of mating pairs, females with
dependent young, and adults denning during cold weather for
thermoregulation. Despite their solitary nature, plains spotted skunks
show no signs of territoriality.
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the plains spotted skunk, and we evaluated all relevant factors
under the five listing factors, including any regulatory mechanisms and
conservation measures addressing these threats. The primary threats
affecting the plains spotted skunk's biological status include habitat
loss and fragmentation due to agricultural and urban development, and
climate change. Impacts from climate change include exacerbation of
drought conditions and a decrease of available habitat along the Gulf
Coast due to sea level rise. We also examined a number of other
factors, including infectious pathogens, pesticides, invasive species,
predation, competition, overexploitation, human-wildlife conflict, and
direct mortality from other sources, but these factors did not rise to
such a level that affected the species as a whole.
To assess the current condition of plains spotted skunks we
analyzed one demographic factor (percent of counties with current
location) and two habitat factors (habitat availability and freshwater
availability) across six population analysis units that cover the
current range of the species. The analysis units cover an extensive
range with a wide diversity of habitats distributed across diverse
environmental conditions. All analysis units had high habitat
availability and at least moderate freshwater availability. The
demographic factor scores ranged from low (two units) to moderate (four
units). Largely due to their extensive range, plains spotted skunks
have a high redundancy and are at a low risk for experiencing rangewide
negative impacts from a catastrophic event at a given point in time.
Similarly, the species demonstrates great adaptive capacity to adjust
to environmental change and, thus, currently exhibits high
representation.
We evaluated two scenarios to characterize the full range of
uncertainty regarding plausible futures for the plains spotted skunk
within a 30-year timeframe. Resiliency of the six analysis units was
assessed under each scenario. Scenario 1 assumes intermediate to low
sea level rise, RCP 4.5 emissions, and land use changes at 2050 from
urbanization and agriculture. Scenario 2 assumes high sea level rise,
RCP 8.5 emissions, and the same land use change projections as scenario
1. Considering both scenarios, we projected the effect of the scenarios
on two habitat factors important to resiliency in the future: habitat
availability and freshwater availability. Under both future scenarios,
we projected some reduction in freshwater availability across the
range. Under scenario 1, we projected one unit scoring low (unit 1) for
freshwater availability, four scoring moderate (units 2-5), and one
unit remaining high (unit 6). Under scenario 2, we projected two units
scoring low for freshwater availability (units 1 and 3), one scoring
moderate (unit 2), and three units remaining high (units 4-6). Under
both scenarios, we projected only minimal reduction in current habitat
availability across the range. Under both scenarios, we project
climate-induced expansion of plains spotted skunks into new habitats
and regions, especially for analysis units 1, 2, and 3. For habitat
availability under both scenarios, we project five units (units 1-5) to
retain high habitat availability and one unit (unit 6) to have moderate
habitat availability. This reduction from currently high habitat
availability in unit 6 to moderate in the future is attributed to sea
level rise on the Gulf Coast of Texas. In either future scenario, we
expect most analysis units to have high to moderate resiliency in terms
of the habitat factors important to the viability of the plains spotted
skunk. Based on an evaluation of the plausible catastrophes likely to
adversely impact plains spotted skunk populations in 2050, we predict
the species will maintain high redundancy in both future scenarios.
Similarly, our analyses of the species' adaptative capacity based on
scenarios 1 and 2 support the likelihood that the species will continue
to exhibit high representation 30 years into the future.
The plains spotted skunk is a generalist species that eats a wide
variety of foods and lives in a wide variety of habitats across six
analysis units that extend across many U.S. States. Current resiliency,
redundancy, and representation are all ranked as moderate to high.
Although there is low distribution in two analysis units, the species'
resiliency overall is moderate to high. The species exhibits high
redundancy, greatly reducing the potential for catastrophic events to
impact the species at the population level, and the species' high
representation indicates a high capacity to adapt to changing
environments. There are no identified threats currently affecting the
species' viability across its range. Based on this information, the
plains spotted skunk is not in danger of extinction throughout all of
its range.
The 3Rs analysis in the SSA report provides evidence that the 30-
year outlook for the species' projected condition under two future
scenarios is still moderate to high. For resiliency, there is almost no
change in habitat availability except for analysis unit 6 (the smallest
unit) due to sea level rise. Freshwater availability drops under both
scenarios, but only two analysis units are projected to be in low
condition, although one of those is analysis unit 3, the largest unit.
No units ranked ``extremely low'' under any future scenarios.
Redundancy and representation are projected to be in the moderate to
high range under both future scenarios. Based on this analysis, the
species is not likely to become endangered in the foreseeable future.
We also evaluated the range of the plains spotted skunk to
determine if the species is in danger of extinction now or likely to
become so within the foreseeable future in any significant portion of
its range. Although there is currently low distribution in two analysis
units, the habitat and freshwater availability in those units is high
to moderate, and there are no barriers to movement or distribution
(other than the Mississippi River on the eastern border of its range).
No threats have been identified that are currently

[[Page 64875]]

affecting any portion of the species' range. Two units are projected to
be in low condition for freshwater availability in the future, and sea
level rise is predicted to decrease habitat availability in another
unit. However, we do not expect freshwater availability to be low
enough to be limiting, and given the retention of high habitat
availability, we expect these units to support the species in the
foreseeable future, especially in light of the plains spotted skunk's
high adaptive capacity. There are no geographic portions of the range
in which the species is potentially endangered or threatened.
After assessing the best available information, we concluded that
the plains spotted skunk is not in danger of extinction or likely to
become in danger of extinction within the foreseeable future throughout
all of its range or in any significant portion of its range. Therefore,
we find that listing the plains spotted skunk as an endangered species
or threatened species under the Act is not warranted. A detailed
discussion of the basis for this finding can be found in the plains
spotted skunk species assessment form and other supporting documents on
<a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket No. FWS-R3-ES-2023-0128 (see
ADDRESSES, above).
Peer Review
In accordance with our July 1, 1994, peer review policy (59 FR
34270; July 1, 1994) and the Service's August 22, 2016, Director's Memo
on the Peer Review Process, we solicited independent scientific reviews
of the information contained in the plains spotted skunk SSA report.
The Service sent the SSA report to four independent peer reviewers and
received two responses. Results of this structured peer review process
can be found at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. We incorporated the
results of these reviews, as appropriate, into the SSA report, which is
the foundation for this finding.

Sturgeon Chub and Sicklefin Chub

Previous Federal Actions
On August 15, 2016, we received a petition dated August 11, 2016,
from WildEarth Guardians requesting that the sturgeon chub
(Macrhybopsis gelida) and sicklefin chub (M. meeki) be listed as
endangered or threatened and that critical habitat be designated for
these species under the Act. On December 20, 2017, we published a 90-
day finding (82 FR 60362) that the petition contained substantial
information indicating that listing may be warranted for these species.
We were later challenged by WildEarth Guardians for our failure to
complete a 12-month finding for these species. Based on this
litigation, we are now required by a September 30, 2021, court order to
submit our 12-month finding for these species to the Federal Register
by September 30, 2023. This document constitutes our 12-month finding
on the August 11, 2016, petition to list sturgeon chub and sicklefin
chub under the Act.
Summary of Finding
The sturgeon chub is a small minnow adapted to benthic riverine
habitats with a slender streamlined body that inhabits turbid mainstem
sections of the Missouri River and Mississippi River and some of their
tributaries. The species has a widespread distribution and currently
occupies 53 percent of its historical range across 12 U.S. States.
The sicklefin chub is a small minnow that inhabits large, turbid
rivers, including the mainstem Missouri and Mississippi Rivers. Like
sturgeon chub, sicklefin chub have also evolved specific adaptations to
turbid, riverine habitats. It is distinguished from the sturgeon chub
by long, sickle-shaped pectoral fins and the absence of ridge-like
projections on its scales. This species also has a widespread
distribution and currently occupies 75 percent of its historical range
across 13 U.S. States.
Sicklefin chub primarily utilize mainstem river habitats, whereas
sturgeon chub utilize both mainstem river and tributary habitat in both
the Missouri and Mississippi River basins. Populations of both species
need large enough areas of connected riverine habitat to fulfill their
life-history needs (e.g., spawning, egg/larval drift distances,
suitable water temperatures, feeding/sheltering habitat) and provide
refugia from habitat-altering stochastic events (e.g., extreme flows
from intense, sustained drought or increased variability in
precipitation). Eggs are spawned in the water column during the summer
months and develop (mediated by water temperature) into larva. Larval
chubs continue to drift in river currents and swim vertically in the
water column with energy provided by the egg yolk sac. Length of
unfragmented reaches needed for larval development varies and is
dependent on water temperature, flow velocity, and habitat complexity,
among other variables. If larvae drift into a reservoir or still water
habitat before they become a horizontal swimmer, it is presumed they
settle to the bottom and experience high mortality. Neither species
occupies the large stretches of reservoir habitat produced by dams
along the Missouri River system.
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the sturgeon chub and sicklefin chub, and we evaluated all relevant
factors under the five listing factors, including any regulatory
mechanisms and conservation measures addressing these threats. The past
construction of mainstem Missouri River dams and associated reservoirs
is the main threat that led to the largest reduction in habitat for
both species. In the future, changes in stream discharge from climate
change is the only threat identified that could potentially lead to
population-level impacts. We also evaluated the effects of channel
modification, water quality, tributary barriers, pollutants,
impingement and entrainment, predation, and hybridization. These
threats are likely impacting both species at an individual level and
not occurring at a scope or scale that would impact entire populations
of these species.
Both sturgeon and sicklefin chubs have high effective population
sizes. Given the amount of habitat fragmentation that occurred
historically, the presence of robust genetics and effective population
estimates, despite the level of fragmentation, is indicative of highly
resilient populations. Current occupancy and abundance information
indicates that populations are in moderate to high condition.
Furthermore, populations of both species currently occupy habitats with
one or more stream fragments meeting or exceeding the minimum
thresholds to meet life-history needs. Sturgeon and sicklefin chubs
currently exhibit high resiliency in multiple populations spread
throughout a large portion of their historical ranges, providing
redundancy against potential catastrophic events. There are no
identified threats currently affecting these species' viability across
their ranges at a population level. Thus, after assessing the best
available information, we conclude that the sturgeon and sicklefin chub
are not in danger of extinction throughout all of their ranges.
When looking to the future, we have no indication that the
construction of additional dams, the demolition of existing dams, or
major differences in dam operations are likely to occur. Similarly, we
have no information to indicate that any of the other potential
stressors identified are going to change in the future at levels that
would impact sturgeon and sicklefin chub populations. The primary
stressor to these species in the future is the

[[Page 64876]]

potential for habitat loss and degradation from climate change. In the
future, we project populations of both species to be relatively
unchanged from their highly resilient current condition. These
populations largely occupy mainstem river habitat, which is not likely
to experience significant impacts from the effects of climate change on
stream discharge. Here, we predict effective population size, occupancy
and abundance, and unfragmented stream length to remain largely stable
in light of potential changes to stream discharge. After assessing the
best available information, we conclude that the sturgeon and sicklefin
chub are not likely to become endangered within the foreseeable future
throughout all of their ranges.
We also evaluated the range of the sturgeon and sicklefin chub to
determine if these species are in danger of extinction now or likely to
become so within the foreseeable future in any portion of their ranges.
For the sturgeon chub, we examined the following threats: Missouri
River mainstem dams and reservoir operations, tributary barriers and
habitat fragmentation, channel modifications, water quality, climate
change, pollutants, impingement/entrainment, predation, and
hybridization, including cumulative effects of the stressors. Except
for climate change, these threats are ubiquitous across the range of
the species and acting on the sturgeon chub more or less equally
rangewide. Although the effect of climate change will impact the entire
range of the species as well, the future impact of climate change on
stream discharge may be more pronounced in the upper reaches of
secondary tributary habitat in two sturgeon chub populations. These
stream reaches are much smaller and as a result less buffered from
future changes in stream discharge resulting from climate change than
the much larger and more stable mainstem river reaches that this
species inhabits. These are the only portions we identified as
potentially having a difference in status than the rangewide status,
and therefore worth considering further for the purposes of this
analysis.
The secondary tributary habitats in the two sturgeon chub
populations mentioned above that may be subject to higher impacts from
climate change constitute approximately 348 stream km (216 mi) out of
5,455 km (3,390 mi) of currently occupied stream km, or approximately 6
percent of the occupied range. These areas are smaller in wetted area
and overall stream discharge than the mainstem river sections occupied
by this species, and as a result may experience larger climate related
swings in stream discharge which could negatively impact chubs living
in those sections. These areas may be used opportunistically by the
species when conditions allow, but these areas offer nothing
ecologically unique and are not required by the sturgeon chub for any
particular point of their life history. The mainstem river sections in
these populations contain more sturgeon chub individuals and contain
all of the same habitat features needed to meet the species' needs,
including sufficient unfragmented stream length for the sturgeon chub
to complete their life cycle and maintain resilient populations into
the future. Based on the small size of this portion relative to the
rest of the range, and the lack of unique habitat features, we do not
consider secondary tributary habitats to be significant for the
purposes of this analysis.
For the sicklefin chub, we examined the following threats: Missouri
River mainstem dams and reservoir operations, tributary barriers and
habitat fragmentation, channel modifications, water quality, climate
change, pollutants, impingement/entrainment, predation, and
hybridization, including cumulative effects. These threats are
ubiquitous across the range of the species and acting on the sicklefin
chub more or less equally rangewide. There are no areas with
disproportionate impacts on sicklefin chub from these threats. Both
sicklefin chub populations are currently high in resiliency and
expected to continue to be so into the future despite the potential
impact of the threats considered. Neither of the two populations
considered as portions on their own meets the definition of an
endangered or threatened species. We found no biologically meaningful
portion of the sicklefin chub's range where threats are impacting
individuals differently from how they are affecting the species
elsewhere in its range, or where the biological condition of the
species differs from its condition elsewhere in its range such that the
status of the species in that portion differs from its status in any
other portion of the species' range. We found no portion of either
species' range that was both significant and in danger of extinction
now or likely to become so within the foreseeable future in that
portion. Therefore, we find that these species are not in danger of
extinction now or likely to become so within the foreseeable future in
any significant portion of their ranges.
After assessing the best available information, we concluded that
sturgeon chub and sicklefin chub are not in danger of extinction or
likely to become in danger of extinction within the foreseeable future
throughout all of their ranges or in any significant portion of their
ranges. Therefore, we find that listing the sturgeon chub and sicklefin
chub as endangered species or threatened species under the Act is not
warranted. A detailed discussion of the basis for this finding can be
found in the sturgeon chub and sicklefin chub species assessment form
and other supporting documents on <a href="https://www.regulations.gov">https://www.regulations.gov</a> under
Docket No. FWS-R6-ES-2023-0131 for the sturgeon chub and Docket No.
FWS-R6-ES-2023-0130 for the sicklefin chub (see ADDRESSES, above).
Peer Review
In accordance with our July 1, 1994, peer review policy (59 FR
34270; July 1, 1994) and the Service's August 22, 2016, Director's Memo
on the Peer Review Process, we solicited appropriate and independent
scientific reviews of the information contained in the sturgeon chub
and sicklefin chub SSA report. The Service sent the SSA report to five
independent peer reviewers and received three responses. Results of
this structured peer review process can be found at <a href="https://www.regulations.gov">https://www.regulations.gov</a> gov. We incorporated the results of these reviews,
as appropriate, into the SSA report, which is the foundation for these
findings.

Tennessee Cave Salamander

Previous Federal Actions
On April 20, 2010, we received a petition from the Center for
Biological Diversity, Alabama Rivers Alliance, Clinch Coalition,
Dogwood Alliance, Gulf Restoration Network, Tennessee Forests Council,
and West Virginia Highlands Conservancy to list 404 aquatic, riparian,
and wetland species, including the Tennessee cave salamander
(Gyrinophilus palleucus), as an endangered or threatened species under
the Act. On September 27, 2011, we published a 90-day finding in the
Federal Register (76 FR 59836) concluding that the petition presented
substantial scientific or commercial information indicating that
listing may be warranted. This document constitutes our 12-month
finding on the April 20, 2010, petition to list the Tennessee cave
salamander under the Act.
Summary of Finding
The Tennessee cave salamander is a large, obligate subterranean
aquatic salamander that currently occurs in 89 caves in central and
southern middle Tennessee, northern Alabama, and

[[Page 64877]]

northwestern Georgia and one spring in Tennessee. Distribution of the
Tennessee cave salamander has not changed significantly since its
discovery in the mid-1940s and extirpation is only known from one site.
Two historical sites were rediscovered with increased survey efforts in
2018.
Little information is available on many aspects of the Tennessee
cave salamander's life history, including egg deposition sites,
incubation, larval habitat and diet, and breeding behavior. The
Tennessee cave salamander requires sufficient water quality and
availability, low sediment load, suitable substrate and cover, and
adequate food sources in a cave ecosystem. The extent of suitable
habitat in occupied cave systems is not mapped, but the three-
dimensional nature of the habitat includes extensive areas that cannot
be accessed and surveyed.
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the Tennessee cave salamander and evaluated all relevant factors
under the five listing factors, including any regulatory mechanisms and
conservation measures addressing these threats. The primary threats
affecting the Tennessee cave salamander's biological status include
habitat destruction or modification (e.g., groundwater pollution from a
variety of sources, sedimentation, mining and quarrying, groundwater
extraction, and cave disturbance), disease, and climate change as well
as the cumulative effects of the various threats on the landscape. Of
the known threats, habitat destruction or modification currently is the
primary threat rangewide to the species' current and future viability.
Impacts to the species' habitat rangewide are caused by groundwater
pollution from contaminants, and sedimentation associated with
urbanization, agriculture, and silviculture. Impacts to individuals and
populations may occur as a result of mining and quarrying, human
visitation, and disease. The best available information does not
indicate that the influence of climate change alone on the species'
current condition is significant, but the effects of climate change may
act synergistically with other threats to exacerbate the effects of
urbanization, drought, and water withdrawal, particularly in the
future.
Although the Tennessee cave salamander is a cryptic species that
occurs in relatively inaccessible subterranean habitat, the best
available information indicates that the species is present in all 12
historically occupied AUs. The Tennessee cave salamander currently
exhibits high resiliency in two AUs and moderate resiliency in eight
AUs. The two AUs in high resiliency make up the stronghold of the
species' range. The two low resiliency AUs occur on the periphery of
the species' range, and each is characterized by relatively few sites
with species occurrence. Approximately 33 percent of known sites and
over 50 percent of sites in the two AUs that make up the stronghold of
the range occur on protected lands that confer some degree of
protection to the species from threats caused by land use.
Representation and redundancy have not declined from historical levels
and are sufficient to support current Tennessee cave salamander
viability. Overall, no threat is acting to an extent or severity such
that the Tennessee cave salamander is at risk of extinction throughout
its range.
The Tennessee cave salamander is expected to remain extant in all
12 AUs in all future scenarios. Our future condition analysis projected
slight declines or declines in resiliency in one to nine AUs depending
on the scenario and time step. There are minor projected increases in
some threats that may affect the availability of suitable habitat
across the species' range. We expect the loss of forest cover to have a
negative impact on the habitat conditions for the species, but there is
limited information quantitatively linking changes in forest cover
surface condition and cave environments in the species' range. The
species' response to projected changes also has not been observed or
quantified.
In the future, the impacts under scenario 1 (status quo minimum)
projected very minor changes to resiliency with only a slight decrease
in one unit in 2040 and three units in 2060. Under scenario 2 (status
quo maximum), with incorporation of a greater magnitude of forest loss,
nine AUs are projected to exhibit no change in resiliency while only
two units are projected to decrease by 2060 (only one unit by 2040).
Under scenario 3 (increased impacts scenario), the magnitude of impact
is greatest, with 5 of 12 AUs projected to exhibit decreased resiliency
in both 2040 and 2060. Nevertheless, even in the greatest impact
scenario, 6 of 12 AUs are projected to exhibit moderate or high
resiliency. The resiliency of the two AUs that make up the stronghold
of the range is not projected to change under any scenario and time
step. No analysis unit-level extirpations are projected. Although
representation and redundancy are projected to decline as a function of
resiliency decreases under some scenarios and time steps, the species
maintains sufficient adaptive capacity and ability to withstand
catastrophic events to support future viability.
Although threats are similar throughout the range of the species,
some local sites may be more affected by specific threats. For example,
the species' response to threats is more pronounced in the Lower
Tennessee and Lower Elk AUs. These AUs currently exhibit low resiliency
driven primarily by low abundance, a lower degree of forest, and a
higher degree of agricultural land use surrounding the low number of
known sites in each AU (three sites in the Lower Tennessee and one site
in the Lower Elk). Given the species' condition within the Lower
Tennessee and Lower Elk AUs, we have identified the two units on the
periphery of the species' range as areas that may be in danger of
extinction now or within the foreseeable future due to the low current
resiliency. Both AUs are projected to decline in resiliency in the
future.
We then proceeded to the question of significance, asking whether
the Lower Tennessee or Lower Elk AU meets the current understanding of
significance. Although the Lower Tennessee and Lower Elk AUs contribute
to the overall species-level representation and redundancy, the two AUs
do not contain any high quality or high value habitat or any habitat or
resources unique to the area and necessary to the Tennessee cave
salamander's life history. In addition, the AUs encompass a low number
of known sites with species' occurrences and do not make up a large
geographic area of the species' range or contain a high proportion of
its habitat or populations. Accordingly, we do not find the Lower
Tennessee or Lower Elk AU, singly or collectively, to be a significant
portion of the range.
After assessing the best available information, we conclude that
the Tennessee cave salamander is not in danger of extinction or likely
to become in danger of extinction within the foreseeable future
throughout all of its range or in any significant portion of its range.
Therefore, we find that listing the Tennessee cave salamander as an
endangered species or threatened species under the Act is not
warranted. A detailed discussion of the basis for this finding can be
found in the Tennessee cave salamander species assessment form and
other supporting documents on <a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket
No. FWS-R4-ES-2023-0133 (see ADDRESSES, above).

[[Page 64878]]

Peer Review
In accordance with our July 1, 1994, peer review policy (59 FR
34270; July 1, 1994) and the Service's August 22, 2016, Director's
Memorandum on the Peer Review Process, we solicited independent
scientific reviews of the information contained in the Tennessee cave
salamander SSA report. The Service sent the SSA report to five
independent peer reviewers and received four responses. Results of this
structured peer review process can be found at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. We incorporated the results of these reviews, as
appropriate, into the SSA report, which is the foundation for this
finding.

Yazoo Crayfish

Previous Federal Actions
The Yazoo crayfish (Faxonius hartfieldi, formerly Orconectes
hartfieldi) was included in a listing petition from the Center for
Biological Diversity et al. (CBD 2010, pp. 792-793) in April 2010. The
petition requested that the Service list 404 aquatic, riparian, and
wetland species as endangered or threatened under the Act. In 2011, the
Service found that this petition presented substantial scientific or
commercial information indicating that listing may be warranted for the
Yazoo crayfish (76 FR 59836; September 27, 2011). This document
constitutes our 12-month finding on the April 2010 petition to list the
Yazoo crayfish under the Act.
Summary of Finding
The Yazoo crayfish is a stream-dwelling species distributed among
scattered locations in the Yazoo and Big Black River drainages in
Mississippi. The species is small growing to 50 to 70 mm (2 to 3 in) in
total length. Historically, the Yazoo crayfish was known from the Yazoo
to the Big Black River drainage in Mississippi. The Yazoo crayfish
currently occupies a wide range of stream sizes from small headwater
streams such as the first order Little Mouse Creek (watershed area: 11
square kilometers (km\2\) (4.25 square miles (m\2\))) to large streams
such as Fourteen mile Creek (watershed area: 644 km\2\ (249 m\2\)).
Occupied streams have moderate gradients and are located in the Lower
and Upper Gulf Coastal Plain ecoregions.
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the Yazoo crayfish and evaluated all relevant factors under the five
listing factors, including any regulatory mechanisms and conservation
measures addressing these threats. The primary threat identified for
the Yazoo crayfish is habitat fragmentation resulting from a number of
factors such as stream channelization, sedimentation, road crossings,
impoundments, and development. Other primary stressors affecting the
species' biological status include regulated river flows, pollution,
and climate change. Sedimentation in streams is often a result of
within channel erosion of banks, head cutting, and stream incisement,
which are usually the result of past land cover and land use practices
(e.g., channelization). Increased sedimentation from a variety of
sources (e.g., timber harvest that does not use best management
practices, row crop agriculture, and urbanization) is detrimental to
stream habitats for a variety of reasons.
Currently, the Yazoo crayfish occupies 12 analytical units across
20 hydrologic unit code (HUC)-12 watersheds in four HUC 8 watersheds
and three level IV ecoregions. Five analytical units are considered to
be high resiliency, three to be moderate resiliency, and four to be low
resiliency. The highest resiliency analytical units are those with a
higher number of occupied watersheds, lower channelization, lower
fragmentation, and higher forest cover. In general, current land use
practices do not appear to have an appreciable negative impact on the
resiliency, redundancy, and representation. Moreover, habitat
conditions for the species have been improving over the past 10-20
years (reduction in agriculture, increase in forested habitat within
occupied watersheds, developed landcover has decreased). Lingering
effects of prior land uses and management practices continue to impact
the species, but there is evidence that streams are recovering from
these land uses and habitat may be improving. Although threats are
present on the landscape, the Yazoo crayfish has multiple moderate and
high resilient populations distributed across the landscape, providing
the species with adequate redundancy and representation. Therefore, the
threats appear to have low imminence and magnitude such that they
currently are not significantly affecting the species' viability. The
SSA report describes some of the uncertainties in the species'
occurrence, populations, and response to threats; however, considering
the available data, the risk of extinction is low due to the
distribution of multiple high and moderate resiliency units across the
species' range. Thus, after assessing the best available information,
we conclude that the Yazoo crayfish is not in danger of extinction
throughout all of its range.
Land use patterns are projected to continue over the next 30 years.
Human population density is low in most of the range, so impacts
related to urbanization and development are generally low and show
minimal change under future scenarios B1 and A2 in 2040. Future
scenarios in 2060 demonstrate an increase of urbanization in some
analytical units, resulting in a decrease in resiliency of four
analytical units under scenario B1 and five analytical units under
scenario A2; however, seven analytical units remain in moderate or high
condition in scenario B1, while eight units remain in moderate or high
condition in scenario A2. Although change is predicted to occur due to
threats on the landscape, our analysis indicates that the magnitude of
change under both scenarios and timesteps does not indicate a
significant risk to future viability of the Yazoo crayfish. The species
is expected to experience slight reductions in resiliency by 2060, but
moderate and high resiliency populations are expected to remain across
the species' range. In addition, recent increases in sampling efforts
have resulted in significant expansion of the species' current range,
and it is predicted that future increases in sampling efforts will
produce similar results. After assessing the best available
information, we conclude that the Yazoo crayfish is not likely to
become endangered within the foreseeable future throughout all of its
range.
We evaluated the range of the Yazoo crayfish to determine if it is
in danger of extinction now or likely to become so within the
foreseeable future in any portion of its range. The species is a range-
limited, stream-dwelling species that occurs within a very small area
distributed among scattered locations in the Yazoo and Big Black River
drainages of Mississippi. The range of a species theoretically can be
divided into portions in an infinite number of ways. We focused our
analysis on portions of the species' range that may meet the Act's
definition of an ``endangered species'' or a ``threatened species.'' We
considered whether the threats or their effects on the Yazoo crayfish
are greater in any biologically meaningful portion of the species'
range than in other portions such that the species is in danger of
extinction now or likely to become so within the foreseeable future in
that portion. Based on the best available science, these factors are
not concentrated within a specific portion

[[Page 64879]]

of the species' range but spread throughout its range.
Currently, there are moderate and high resiliency populations
occurring in each ecoregion. In Northern Hilly Gulf Coastal Plain,
there are two moderate resiliency populations and one low resiliency
population. In Southern Hilly Gulf Coastal Plain, there are two low
resiliency populations and one high resiliency population. In Loess
Plain, there are two moderate resiliency populations and four high
resiliency populations. We project in the future at least one moderate
and/or high resiliency population occurring in each ecoregion: In
Northern Hilly Gulf Coastal Plain, there are projected to be two low
resiliency populations and one moderate resiliency population; in
Southern Hilly Gulf Coastal Plain, there are projected to be two very
low resiliency populations and one moderate resiliency population; and
in Loess Plain, there are projected to be three moderate resiliency
populations and three high resiliency populations. The current and
future condition analyses of the Yazoo crayfish indicate sufficient
resiliency, representation, and redundancy in each ecoregion. As a
result, there are no portions of the species' range where the species
has a different biological status from its rangewide biological status.
Therefore, we conclude that there are no portions of the species' range
that warrant further consideration, and the species is not in danger of
extinction or likely to become so within the foreseeable future in any
significant portion of its range.
After assessing the best available information, we conclude that
the Yazoo crayfish is not in danger of extinction or likely to become
in danger of extinction within the foreseeable future throughout all of
its range or in any significant portion of its range. Therefore, we
find that listing the Yazoo crayfish as an ``endangered species'' or
``threatened species'' under the Act is not warranted. A detailed
discussion of the basis for this finding can be found in the Yazoo
crayfish species assessment form and other supporting documents on
<a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket No. FWS-R4-ES-2023-0134 (see
ADDRESSES, above).
Peer Review
In accordance with our July 1, 1994, peer review policy (59 FR
34270; July 1, 1994) and the Service's August 22, 2016, Director's Memo
on the Peer Review Process, we solicited independent scientific reviews
of the information contained in the Yazoo crayfish SSA report. The
Service sent the SSA report to five independent peer reviewers and
received two responses. Results of this structured peer review process
can be found at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. We incorporated the
results of these reviews, as appropriate, in the SSA report, which is
the foundation for this finding.

Southern Sea Otter

Previous Federal Actions
On January 14, 1977, we published a final rule (42 FR 2965) to list
the southern sea otter as a threatened species. On March 10, 2021, we
received a November 2020 petition from the Pacific Legal Foundation,
counsel for California Sea Urchin Commission and Commercial Fishermen
of Santa Barbara, requesting that the southern sea otter (Enhydra
lutris nereis) be removed from the Federal List of Endangered and
Threatened Wildlife (i.e., ``delisted'') because the species does not
meet the Act's definition of an endangered or a threatened species. On
August 23, 2022, we published a 90-day finding (87 FR 51635) that the
petition presented substantial scientific or commercial information
indicating that delisting the southern sea otter may be warranted. This
document constitutes our 12-month finding on the March 10, 2021,
petition to delist southern sea otter.
Summary of Finding
The southern sea otter historically ranged from Oregon in the
United States (which is thought to have been a transition zone between
the northern and southern subspecies), to the species' southern range
terminus near Punta Abreojos, Baja California, Mexico. The maritime fur
trade of the 18th and 19th centuries caused the near-extinction of sea
otters throughout their North Pacific range. All present-day southern
sea otters descended from a small remnant population that survived the
fur trade near Bixby Creek in Monterey County, California. Currently,
the subspecies occurs only in portions of California: along roughly 500
km (310 mi) of the mainland coastline from San Mateo County to Santa
Barbara County, and in the waters surrounding San Nicolas Island,
Ventura County, although occasionally individuals are documented in
other areas.
Southern sea otters occupy a variety of coastal marine habitats,
including rocky exposed coastline, sandy embayments, and estuaries. Sea
otter habitat in California is typically defined by the 40 m (131 ft)
or 60 m (197 ft) depth contour. Depending on local bathymetry, most sea
otters in California reside within 2 km (1.2 mi) of shore. At the
individual level, sea otters need benthic invertebrate prey, coastal
marine waters less than 40 m (131 ft) in depth, and sheltered resting
habitat consisting of canopy-forming kelp, shallow protected waters
(e.g., estuaries), or haul out areas. At the population level, sea
otters need sufficient abundance and adequate rates of survival,
recruitment, and dispersal to rebound from disturbance and persist at
the population or metapopulation scale. At the species level, sea
otters need adequate redundancy to spread the risk of large-scale,
high-impact (i.e., catastrophic) events among multiple populations or
areas; they also need adequate genetic and environmental diversity to
be able to adapt to changing environmental conditions.
For additional information on the physical characteristics,
genetics, taxonomy, habitat, life history, and historical and current
distribution, see chapter 3 of the SSA report (Service 2023, pp. 12-26.
For additional information on population and species needs, see chapter
3 of the SSA report (Service 2023, pp. 22-23).
We have carefully assessed the best scientific and commercial
information available regarding the past, present, and future threats
to the southern sea otter, and we evaluated all relevant factors under
the five listing factors including any regulatory mechanisms and
conservation measures addressing these threats. We examined the
following threats: curtailment of its range; harmful algal or
cyanobacterial bloom intoxication; shark bite mortality; end-lactation
syndrome; cardiac disease; protozoal infection; acanthocephalan
peritonitis; infections (other); natural causes (other); human causes
(shootings, boat strikes, and entanglements); human causes (oil
spills); loss of genetic diversity; and climate change, including
synergistic and cumulative effects. Of these threats, the southern sea
otter is currently most imperiled by high shark bite mortality,
curtailment of its range, and changes related to climate.
Due in part to listing under the Act in 1977 and ongoing
conservation efforts, the range-wide population index for southern sea
otters has increased to 2,962 as of 2019 (the most recent year a full
census was completed); the mainland range has increased by
approximately 210 km (130 mi) to encompass roughly 500 km (310 mi) of
linear coastline; and a translocated subpopulation has taken hold at
San Nicolas Island. Although current numbers and range remain
restricted, the southern sea otter is likely to sustain populations in
the wild in the near term. The current abundance of 2,962

[[Page 64880]]

otters is far below estimated carrying capacity of California, but
above the roughly 50 animals that remained in 1914. Seven of 29+
subpopulations are currently extant. However, the results of population
projections based on three plausible future scenarios indicated that
meaningful improvements in resiliency, redundancy, and representation
are unlikely to occur within the foreseeable future.
As noted above, the southern sea otter remains most imperiled by
high shark bite mortality, the curtailment of its range, and climate
change and associated effects. Based on our projections of future
conditions for the species, and the existing and increased threats in
the future on the species from shark bite mortality, range curtailment,
and impacts of climate change, the species will experience continued
and increasing impacts on its abundance and connectivity between
populations that will most likely cause the species to be increasingly
less able to support itself into the future. Additionally, existing
regulatory mechanisms and conservation measures do not appear to be
sufficient to protect the southern sea otter from emerging or
intensifying threats.
After assessing the best available information, we concluded that
southern sea otter is likely to become in danger of extinction within
the foreseeable future throughout all of its range. Therefore, we find
that delisting the southern sea otter under the Act is not warranted. A
detailed discussion of the basis for this finding can be found in the
southern sea otter species assessment form and other supporting
documents on <a href="https://www.regulations.gov">https://www.regulations.gov</a> under Docket No. FWS-R8-ES-
2023-0132 (see ADDRESSES, above).
Peer Review
In accordance with our July 1, 1994, peer review policy (59 FR
34270; July 1, 1994) and the Service's August 22, 2016, Director's Memo
on the Peer Review Process, we solicited independent scientific reviews
of the information contained in the southern sea otter SSA report. The
Service sent the SSA report to three independent peer reviewers and
three partner reviewers. We received responses back from one peer
reviewer and one partner reviewer. Results of this structured peer
review process can be found at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. We
incorporated the results of these reviews, as appropriate, into the SSA
report, which is the foundation for this finding.

New Information

We request that you submit any new information concerning the
taxonomy, biology, ecology, status of, or stressors to the Cascades
frog, plains spotted skunk, sicklefin chub, southern sea otter,
sturgeon chub, Tennessee cave salamander, or Yazoo crayfish to the
appropriate person, as specified under FOR FURTHER INFORMATION CONTACT,
whenever it becomes available. New information will help us monitor
these species and make appropriate decisions about their conservation
and status. We encourage local agencies and stakeholders to continue
cooperative monitoring and conservation efforts.

References Cited

A list of the references cited in each petition finding is
available in the relevant species assessment form, which is available
on the internet at <a href="https://www.regulations.gov">https://www.regulations.gov</a> in the appropriate
docket (see ADDRESSES, above) and upon request from the appropriate
person (see FOR FURTHER INFORMATION CONTACT, above).

Authors

The primary authors of this document are the staff members of the
Species Assessment Team, Ecological Services Program.

Authority

The authority for this action is section 4 of the Endangered
Species Act of 1973, as amended (16 U.S.C. 1531 et seq.).

Martha Williams,
Director, U.S. Fish and Wildlife Service.
[FR Doc. 2023-20296 Filed 9-19-23; 8:45 am]
BILLING CODE 4333-15-P

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