[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 [www.gpo.gov]
[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 https://www.regulations.gov under the 
following docket numbers:

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               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"><span class="__cf_email__" data-cfemail="09636c6f6f7b6c70566d6065656667496f7e7a276e667f">[email protected]</span></a>, 503-231-
                                     6179.
Plains spotted skunk..............  John Weber, Field Supervisor,
                                     Missouri Field Office,
                                     <a href="/cdn-cgi/l/email-protection#672d080f0938343830020502152701101449000811"><span class="__cf_email__" data-cfemail="602a0f080e3f333f3705020512200617134e070f16">[email protected]</span></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"><span class="__cf_email__" data-cfemail="0d6c60647974526f6c7e7e4d6b7a7e236a627b">[email protected]</span></a>, 605-
                                     222-0228.
Southern sea otter................  Steve Henry, Field Supervisor,
                                     Ventura Fish and Wildlife Office,
                                     <a href="/cdn-cgi/l/email-protection#3e4d4a5b485b61565b504c477e58494d10595148"><span class="__cf_email__" data-cfemail="691a1d0c1f0c36010c071b10290f1e1a470e061f">[email protected]</span></a>, 805-644-1766.
Tennessee cave salamander.........  Dan Elbert, Field Supervisor,
                                     Tennessee FO,
                                     <a href="/cdn-cgi/l/email-protection#e98d8887808c85b68c858b8c9b9da98f9e9ac78e869f"><span class="__cf_email__" data-cfemail="f591949b9c9099aa909997908781b5938286db929a83">[email protected]</span></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"><span class="__cf_email__" data-cfemail="80eae1ede5f3dfe1f5f3f4e9eec0e6f7f3aee7eff6">[email protected]</span></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 https://www.regulations.gov 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 https://www.regulations.gov 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 https://www.regulations.gov. 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 
https://www.regulations.gov 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 https://www.regulations.gov. 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 https://www.regulations.gov 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 https://www.regulations.gov 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 https://www.regulations.gov 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 https://www.regulations.gov. 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 
https://www.regulations.gov 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 https://www.regulations.gov. 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 https://www.regulations.gov 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 https://www.regulations.gov. 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 https://www.regulations.gov 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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