[Federal Register Volume 89, Number 157 (Wednesday, August 14, 2024)]
[Notices]
[Pages 66068-66091]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-18130]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XE173]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Office of Naval Research's 
Arctic Research Activities in the Beaufort and Chukchi Seas (Year 7)

AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and 
Atmospheric Administration (NOAA), Commerce.

ACTION: Notice; proposed incidental harassment authorization; request 
for comments on proposed authorization and possible renewal.

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SUMMARY: NMFS has received a request from the Office of Naval Research 
(ONR) for authorization to take marine mammals incidental to Arctic 
Research Activities (ARA) in the Beaufort Sea and eastern Chukchi Sea. 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-time, 1-year renewal that could be issued under certain 
circumstances and if all requirements are met, as described in Request 
for Public Comments at the end of this notice. NMFS will consider 
public comments prior to making any final decision on the issuance of 
the requested MMPA authorization and agency responses will be 
summarized in the final notice of our decision. The ONR's activities 
are considered military readiness activities pursuant to the MMPA, as 
amended by the National Defense Authorization Act for Fiscal Year 2004 
(2004 NDAA).

DATES: Comments and information must be received no later than 
September 13, 2024.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be submitted via email to 
[email protected]. Electronic copies of the application and 
supporting documents, as well as a list of the references cited in this 
document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities. In case of problems accessing these 
documents, please call the contact listed below.
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Alyssa Clevenstine, Office of 
Protected Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION:

[[Page 66069]]

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to 
allow, upon request, the incidental, but not intentional, taking of 
small numbers of marine mammals by U.S. citizens who engage in a 
specified activity (other than commercial fishing) within a specified 
geographical region if certain findings are made and either regulations 
are proposed or, if the taking is limited to harassment, a notice of a 
proposed IHA is provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the monitoring and 
reporting of the takings. The definitions of all applicable MMPA 
statutory terms cited above are included in the relevant sections 
below.
    The 2004 NDAA (Pub. L. 108-136) removed the ``small numbers'' and 
``specified geographical region'' limitations indicated above and 
amended the definition of ``harassment'' as applied to a ``military 
readiness activity.'' The activity for which incidental take of marine 
mammals is being requested qualifies as a military readiness activity.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment.
    In 2018, the U.S. Navy prepared an Overseas Environmental 
Assessment (OEA) analyzing the project. Prior to issuing the IHA for 
the first year of this project, NMFS reviewed the 2018 EA and the 
public comments received, determined that a separate NEPA analysis was 
not necessary, and subsequently adopted the document and issued a NMFS 
Finding of No Significant Impact (FONSI) in support of the issuance of 
an IHA (83 FR 48799, September 27, 2018).
    In 2019, the Navy prepared a supplemental OEA. Prior to issuing the 
IHA in 2019, NMFS reviewed the supplemental OEA and the public comments 
received, determined that a separate NEPA analysis was not necessary, 
and subsequently adopted the document and issued a NMFS FONSI in 
support of the issuance of an IHA (84 FR 50007, September 24, 2019).
    In 2020, the Navy submitted a request for a renewal of the 2019 
IHA. Prior to issuing the renewal IHA, NMFS reviewed ONR's application 
and determined that the proposed action was identical to that 
considered in the previous IHA. Because no significantly new 
circumstances or information relevant to any environmental concerns had 
been identified, NMFS determined that the preparation of a new or 
supplemental NEPA document was not necessary and relied on the 
supplemental OEA and FONSI from 2019 when issuing the renewal IHA in 
2020 (85 FR 41560, July 10, 2020).
    In 2021, the Navy submitted a request for an IHA for incidental 
take of marine mammals during continuation of ARA. NMFS reviewed the 
Navy's OEA and determined it to be sufficient for taking into 
consideration the direct, indirect, and cumulative effects to the human 
environment resulting from continuation of the ARA. NMFS subsequently 
adopted that OEA and signed a FONSI (86 FR 54931, October 5, 2021).
    In 2022, the Navy submitted a request for an IHA for incidental 
take of marine mammals during continuation of ARA and prepared an OEA 
analyzing the project. Prior to issuing the IHA for the project, we 
reviewed the 2022-2025 OEA and the public comments received, determined 
that a separate NEPA analysis was not necessary, and subsequently 
adopted the document and issued our own FONSI in support of the 
issuance of an IHA (87 FR 57458, September 20, 2022).
    In 2023, the ONR requested a renewal of the 2022 IHA for ongoing 
ARA from September 2023 to September 2024, and the 2022 IHA monitoring 
report. Prior to issuing the renewal IHA, NMFS reviewed ONR's 
application and determined that the proposed action was identical to 
that considered in the previous IHA. Because no significantly new 
circumstances or information relevant to any environmental concerns 
were identified, NMFS determined that the preparation of a new or 
supplemental NEPA document was not necessary and relied on the 
supplemental OEA and FONSI from 2022 when issuing the renewal IHA in 
2023 (88 FR 65657, September 18, 2023).
    Accordingly, NMFS preliminarily has determined to adopt the Navy's 
OEA for ONR ARA in the Beaufort and Chukchi Seas 2022-2025, provided 
our independent evaluation of the document finds that it includes 
adequate information analyzing the effects on the human environment of 
issuing the IHA. NMFS is a not cooperating agency on the U.S. Navy's 
OEA.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On March 29, 2024, NMFS received a request from the ONR for an IHA 
to take marine mammals incidental to ARA in the Beaufort and Chukchi 
Seas. Following NMFS' review of the application, the ONR submitted a 
revised version on July 23, 2024. The application was deemed adequate 
and complete on August 5, 2024. The ONR's request is for take of beluga 
whales and ringed seals by Level B harassment only. Neither the ONR nor 
NMFS expect serious injury or mortality to result from this activity 
and, therefore, an IHA is appropriate.
    This proposed IHA would cover the seventh year of a larger project 
for which ONR obtained prior IHAs and renewal IHAs (83 FR 48799, 
September 27, 2018; 84 FR 50007, September 24, 2019; 85 FR 53333, 
August 28, 2020; 86 FR 54931, October 5, 2021; 87 FR 57458, September 
20, 2022; 88 FR 65657, September 18, 2023). ONR has complied with all 
the requirements (e.g., mitigation, monitoring, and reporting) of the 
previous IHAs.

Description of Proposed Activity

Overview

    The ONR proposes to conduct scientific experiments in support of 
ARA using active acoustic sources within the Beaufort and Chukchi Seas. 
Project activities involve acoustic testing and a multi-frequency 
navigation system concept test using left-behind active acoustic 
sources. The proposed experiments involve the deployment of moored, 
drifting, and ice-tethered active acoustic sources from the Research 
Vessel (R/V) Sikuliaq. Recovery of equipment may be from R/V Sikuliaq,

[[Page 66070]]

U.S. Coast Guard Cutter (CGC) HEALY, or another vessel, and icebreaking 
may be required. Underwater sound from the active acoustic sources and 
noise from icebreaking may result in Level B harassment of marine 
mammals.

Dates and Duration

    The proposed action would occur from September 2024 through 
September 2025 and include up to two research cruises. Acoustic testing 
would take place during the cruises, with the first cruise beginning 
September 2, 2024, and a potential second cruise occurring in summer or 
fall 2025, which may include up to 8 days of icebreaking activities.

Geographic Region

    The proposed action would occur across the U.S. Exclusive Economic 
Zone (EEZ) in the Beaufort and Chukchi Seas, partially in the high seas 
north of Alaska, the Global Commons, and within a part of the Canadian 
EEZ (in which the appropriate permits would be obtained by the Navy) 
(figure 1). The proposed action would primarily occur in the Beaufort 
Sea but the analysis considers the drifting of active sources on buoys 
into the eastern portion of the Chukchi Sea. The closest point of the 
study area to the Alaska coast is 204 kilometers (km; 110 nautical 
miles (nm)). The proposed study area is approximately 639,267 square 
kilometers (km\2\).

[[Page 66071]]

[GRAPHIC] [TIFF OMITTED] TN14AU24.000

Detailed Description of the Specified Activity

    The ONR ARA Global Prediction Program supports two major projects: 
Stratified Ocean Dynamics of the Arctic (SODA) and Arctic Mobile 
Observing System (AMOS). The SODA and AMOS projects have been 
previously discussed in association with previously issued IHAs (83 FR 
40234, August 14, 2018; 84 FR 37240, July 31, 2019). However, only 
activities relating to the AMOS project will occur during the period 
covered by this proposed action.
    The proposed action constitutes the development of a modified 
system under the ONR AMOS involving very-low-, low-, and mid-frequency 
(VLF, LF, MF) transmissions (35 Hertz (Hz), 900 Hz, and 10 kilohertz 
(kHz), respectively). The AMOS project utilizes acoustic sources and 
receivers to provide a means of performing under-ice navigation for 
gliders and unmanned undersea vehicles (UUVs). This would allow for the 
possibility of year-round scientific observations of the environment in 
the Arctic. As an environment that is particularly affected by climate 
change, year-round observations under a variety of ice conditions are 
required to study the

[[Page 66072]]

effects of this changing environment for military readiness, as well as 
the implications of environmental change to humans and animals. VLF 
technology is important in extending the range of navigation systems 
and has the potential to allow for development and use of navigational 
systems that would not be heard by some marine mammal species and, 
therefore, would be less impactful overall.
    Up to six moorings (four fixed acoustic navigation sources 
transmitting at 900 Hz, two fixed VLF sources transmitting at 35 Hz) 
and two drifting ice gateway buoys (IGBs) would be configured with 
active acoustic sources and would operate for a period of up to 1 year. 
Four gliders with passive acoustics would be used to support drifting 
IGBs. No UUV use is planned during the September 2024 research cruise; 
however, there is the potential for one UUV (without active acoustic 
sources) to be deployed and up to 8 days of icebreaking activities to 
occur on a potential research cruise in summer/fall 2025, which would 
require the use of a vessel with ice-breaking capabilities (e.g., CGC 
HEALY).
    During the research cruise, acoustic sources would be deployed from 
the vessel for intermittent testing of the system components, which 
would take place in the vicinity of the source locations (figure 1). 
During this testing, 35 Hz, 900 Hz, 10 kHz, and acoustic modems would 
be employed. The six fixed moorings would be anchored on the seabed and 
held in the water column with subsurface buoys.
    Autonomous vehicles would be able to navigate by receiving acoustic 
signals from multiple locations and triangulating. This is needed for 
vehicles that are under ice and cannot communicate with satellites. 
Source transmits would be offset by 15 minutes from each other (i.e., 
sources would not be transmitting at the same time). All navigation 
sources would be recovered. The purpose of the navigation sources is to 
orient UUVs and gliders in situations when they are under ice and 
cannot communicate with satellites.
    The proposed action would utilize non-impulsive acoustic sources, 
although not all sources will cause take of marine mammals (tables 1, 
2). Marine mammal takes would arise from the operation of non-impulsive 
active sources. Although not currently planned, icebreaking could occur 
as part of this proposed action if a research vessel needs to return to 
the study area before the end of the IHA period to ensure scientific 
objectives are met. In this case, icebreaking could result in Level B 
harassment.
    Below are descriptions of the platforms and equipment that would be 
deployed at different times during the proposed activity.
Research Vessels
    The R/V Sikuliaq would perform the research cruise in September 
2024 and conduct testing of acoustic sources during the cruise, as well 
as leave sources behind to operate as a year-round navigation system 
observation. The vessel to be used in a potential 2025 cruise is yet to 
be determined but the most probable option would be the CGC HEALY.
    The R/V Sikuliaq has a maximum speed of approximately 12 knots 
(22.2 km per hour (km/hr)) with a cruising speed of 11 knots (20.4 km/
hr). The R/V Sikuliaq is not an icebreaking ship but an ice 
strengthened ship. It would not be icebreaking and therefore acoustic 
signatures of icebreaking for the R/V Sikuliaq are not relevant. CGC 
HEALY travels at a maximum speed of 17 knots (31.5 km/hr) with a 
cruising speed of 12 knots (22.2 km/hr) and a maximum speed of 3 knots 
(5.6 km/hr) when traveling through 1.07 m (3.5 ft) of sea ice. While no 
icebreaking cruise on the CGC HEALY is scheduled during the IHA period, 
need may arise. Therefore, for the purposes of this IHA application, an 
icebreaking cruise is considered.
    The R/V Sikuliaq, CGC HEALY, or any other vessel operating a 
research cruise associated with the Proposed Action may perform the 
following activities during their research cruises:
     Deployment of moored and/or ice-tethered passive sensors 
(oceanographic measurement devices, acoustic receivers);
     Deployment of moored and/or ice-tethered active acoustic 
sources to transmit acoustic signals;
     Deployment of UUVs;
     Deployment of drifting buoys, with or without acoustic 
sources; or,
     Recovery of equipment.
Glider Surveys
    Glider surveys are proposed for the research cruise. All gliders 
would be recovered; some may be recovered during the cruise, but the 
remainder would be recovered at a later date. Up to four gliders would 
be deployed during the research cruise as part of on-ice operations 
(one to two gliders would be associated with each on-ice station).
    Long-endurance, autonomous sea gliders are intended for use in 
extended missions in ice-covered waters. Gliders are buoyancy-driven, 
equipped with satellite modems providing two-way communication, and are 
capable of transiting to depths of up to 1,000 m (3,280 ft). Gliders 
would collect data in the area of the shallow water sources and moored 
sources, moving at a speed of 0.25 meters per second (m/s; 23 
kilometers per day (km/day)). A combination of recent advances in sea 
glider technology would provide full-year endurance. When operating in 
ice-covered waters, gliders navigate by trilateration (the process of 
determining location by measurement of distances, using the geometry of 
circles, spheres or triangles) from moored acoustic sound sources (or 
dead reckoning should navigation signals be unavailable); they do not 
contain any active acoustic sources. Hibernating gliders would continue 
to track their position, waking to reposition should they drift too far 
from their target region. Gliders would measure temperature, salinity, 
dissolved oxygen, rates of dissipation of temperature variance (and 
vertical turbulent diffusivity), and multi-spectral down welling 
irradiance.
Moored and Drifting Acoustic Sources
    During the September 2024 cruise, active acoustic sources would be 
lowered from the cruise vessel while stationary, deployed on gliders 
and UUVs, or deployed on fixed AMOS and VLF moorings for intermittent 
testing of the system components. The testing would take place in the 
vicinity of the source locations in figure 1. During this testing, 35 
Hz, 900 Hz, 10 kHz, and acoustic modems would be employed. No UUV use 
is planned during the September 2024 research cruise but UUV use may be 
included in future test plans covered by this IHA.
    Up to four fixed acoustic navigation sources transmitting at 900 Hz 
would remain in place for a year. These moorings would be anchored on 
the seabed and held in the water column with subsurface buoys. All 
sources would be deployed by shipboard winches, which would lower 
sources and receivers in a controlled manner. Anchors would be steel 
``wagon wheels'' typically used for this type of deployment. Two VLF 
sources transmitting at 35 Hz would be deployed in a similar manner. 
Two drifting IGBs would also be configured with active acoustic 
sources.

[[Page 66073]]



                                                  Table 1--Characteristics of Modeled Acoustic Sources
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                                                                                                             Signal strength (dB      Pulse width/duty
  Platform (total number deployed)       Acoustic source       Purpose/ function           Frequency         re 1 [mu]Pa at 1 m)           cycle
--------------------------------------------------------------------------------------------------------------------------------------------------------
REMUS 600 UUV \a\ (up to 1)........  WHOI Micro-modem......  Acoustic               900-950 Hz............  NTE 180 dB by sys      5 pings/hour with 30
                                                              communications.                                design limits.         sec pulse length.
REMUS 600 UUV \a\ (up to 1)........  UUV/WHOI Micro-modem..  Acoustic               8-14 kHz..............  NTE 185 dB by sys      10% average duty
                                                              communications.                                design limits.         cycle, with 4 sec
                                                                                                                                    pulse length.
IGB (drifting) (2).................  WHOI Micro-modem......  Acoustic               900-950 Hz............  NTE 180 dB by sys      Transmit every 4
                                                              communications.                                design limits.         hours, 30 sec pulse
                                                                                                                                    length.
IGB (drifting) (2).................  WHOI Micro-modem......  Acoustic               8-14 kHz..............  NTE 185 dB by sys      Typically receive
                                                              communications.                                design limits.         only. Transmit is
                                                                                                                                    very intermittent.
Mooring (6)........................  WHOI Micro-modem (4)..  Acoustic Navigation..  900-950 Hz............  NTE 180 dB by sys      Transmit every 4
                                                                                                             design limits.         hours, 30 sec pulse
                                                                                                                                    length.
Mooring (6)........................  VLF (2)...............  Acoustic Navigation..  35 Hz.................  NTE 190 dB...........  Up to 4 times per
                                                                                                                                    day, 10 minutes
                                                                                                                                    each.
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Note: dB re 1 [mu]Pa at 1 m = decibels referenced to 1 microPascal at 1 meter; Hz = Hertz; IGB = Ice Gateway Buoy; kHz = kilohertz; NTE = not to exceed;
  VLF = very low frequency; WHOI = Woods Hole Oceanographic Institution.
\a\ REMUS use is not anticipated during the September 2024 cruise but is included in case of future use during the proposed IHA period.

Activities Not Likely To Result in Take
    The following activities have been determined to be unlikely to 
result in take of marine mammals. These activities are described here 
but they are not discussed further in this notice.
    De minimis Sources--The ONR characterizes de minimis sources as 
those with the following parameters: low source levels (SLs), narrow 
beams, downward directed transmission, short pulse lengths, frequencies 
outside known marine mammal hearing ranges, or some combination of 
these factors (Navy, 2013). NMFS concurs with the ONR's determination 
that the sources they have identified here as de minimis are unlikely 
to result in take of marine mammals. The following are some of the 
planned de minimis sources which would be used during the proposed 
action: Woods Hole Oceanographic Institution (WHOI) micromodem, 
Acoustic Doppler Current Profilers (ADCPs), ice profilers, and 
additional sources below 160 decibels referenced to 1 microPascal (dB 
re 1 [mu]Pa) used during towing operations. ADCPs may be used on 
moorings. Ice-profilers measure ice properties and roughness. The ADCPs 
and ice-profilers would all be above 200 kHz and therefore out of 
marine mammal hearing ranges, with the exception of the 75 kHz ADCP 
which has the characteristics and de minimis justification listed in 
table 2. They may be employed on moorings or UUVs.
    A WHOI micromodem will also be employed during the leave behind 
period. In contrast with the WHOI micromodem usage described in table 
1, which covers the use of the micromodem during research cruises, the 
use of the source during the leave behind period differs in nature. 
During this period, it is being used for very intermittent 
communication with vehicles to communicate vehicle status for safety of 
navigation purposes, and is treated as de minimis while employed in 
this manner.

                        Table 2--Parameters for De Minimis Non-Impulsive Acoustic Sources
----------------------------------------------------------------------------------------------------------------
                                                Sound pressure
          Source name              Frequency    level (dB re 1   Pulse length     Duty cycle       De minimis
                                  range (kHz)   [mu]Pa at 1 m)     (seconds)       (percent)      justification
----------------------------------------------------------------------------------------------------------------
ADCP..........................   >200, 150, or             190          <0.001            <0.1  Very low pulse
                                            75                                                   length, narrow
                                                                                                 beam, moderate
                                                                                                 source level.
Nortek Signature 500 kHz                   500             214            <0.1             <13  Very high
 Doppler Velocity Log.                                                                           frequency.
CTD Attached Echosounder......            5-20             160           0.004               2  Very low source
                                                                                                 level.
----------------------------------------------------------------------------------------------------------------
Note: dB re 1 [mu]Pa at 1 m = decibels referenced to 1 microPascal at 1 meter; kHz = kilohertz; ADCP = acoustic
  Doppler current profiler; CTD = conductivity temperature depth.

    Drifting Oceanographic Sensors--Observations of ocean-ice 
interactions require the use of sensors that are moored and embedded in 
the ice. For the proposed action, it will not be required to break ice 
to do this, as deployments can be performed in areas of low ice-
coverage or free floating ice. Sensors are deployed within a few dozen 
meters of each other on the same ice floe. Three types of sensors would 
be used: autonomous ocean flux buoys, Integrated Autonomous Drifters, 
and ice-tethered profilers. The autonomous ocean flux buoys measure 
oceanographic properties just below the ocean-ice interface. The 
autonomous ocean flux buoys would have ADCPs and temperature chains 
attached, to measure temperature, salinity, and other ocean parameters 
the top 6 m (20 ft) of the water column. Integrated Autonomous Drifters 
would have a long temperate string extending down to 200 m (656 ft) 
depth and would incorporate meteorological sensors, and a temperature 
spring to estimate ice thickness. The ice-tethered profilers would 
collect information on ocean temperature, salinity, and velocity down 
to 250 m (820 ft) depth.
    Up to 20 Argo-type autonomous profiling floats may be deployed in 
the central Beaufort Sea. Argo float drift at 1,500 m (4,921 ft) depth, 
profiling from 2,000 m (6,562 ft) to the sea surface once every 10 days 
to collect profiles of

[[Page 66074]]

temperature and salinity. Moored Oceanographic Sensors--Moored sensors 
would capture a range of ice, ocean, and atmospheric conditions on a 
year-round basis. These would be bottom anchored, sub-surface moorings 
measuring velocity, temperature, and salinity in the upper 500 m (1,640 
ft) of the water column. The moorings also collect high-resolution 
acoustic measurements of the ice using the ice profilers described 
above. Ice velocity and surface waves would be measured by 500 kHz 
multibeam sonars from Nortek Signatures. The moored oceanographic 
sensors described above use only de minimis sources and are therefore 
not anticipated to have the potential for impacts on marine mammals or 
their habitat. On-ice Measurements--On-ice measurement systems would be 
used to collect weather data. These would include an Autonomous Weather 
Station and an Ice Mass Balance Buoy. The Autonomous Weather Station 
would be deployed on a tripod; the tripod has insulated foot platforms 
that are frozen into the ice. The system would consist of an 
anemometer, humidity sensor, and pressure sensor. The Autonomous 
Weather Station also includes an altimeter that is de minimis due to 
its very high frequency (200 kHz). The Ice Mass Balance Buoy is a 6 m 
(20 ft) sensor string, which is deployed through a 5 centimeter (cm; 2 
inch (in)) hole drilled into the ice. The string is weighted by a 1 
kilogram (kg; 2.2 pound (lb)) lead weight and is supported by a tripod. 
The buoy contains a de minimis 200 kHz altimeter and snow depth sensor. 
Autonomous Weather Stations and Ice Mass Balance Buoys will be deployed 
and will drift with the ice, making measurements until their host ice 
floes melt, thus destroying the instruments (likely in summer, roughly 
1 year after deployment). After the on-ice instruments are destroyed 
they cannot be recovered and would sink to the seafloor as their host 
ice floes melted.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history of the potentially affected species. NMFS 
fully considered all of this information, and we refer the reader to 
these descriptions, instead of reprinting the information. Additional 
information regarding population trends and threats may be found in 
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and 
more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
    Table 3 lists all species or stocks for which take is expected and 
proposed to be authorized for this activity and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. PBR is defined by the MMPA as the maximum 
number of animals, not including natural mortalities, that may be 
removed from a marine mammal stock while allowing that stock to reach 
or maintain its optimum sustainable population (as described in NMFS' 
SARs). While no serious injury or mortality is anticipated or proposed 
to be authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Alaska SARs (Young et al., 2023). All values presented in 
table 3 are the most recent available at the time of publication and 
are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                            Table 3--Species Likely Impacted by the Specified Activities \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/MMPA status;    Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \2\          abundance survey) \3\               SI \4\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga Whale........................  Delphinapterus leucas..  Beaufort Sea...........  -, -, N             39,258 (0.229, N/A,           UND        104
                                                                                                             1992).
Beluga Whale........................  Delphinapterus leucas..  Eastern Chukchi........  -, -, N             13,305 (0.51, 8,875,          178         56
                                                                                                             2017).
Ringed Seal.........................  Pusa hispida...........  Arctic.................  T, D, Y             UND \5\ (UND, UND,            UND      6,459
                                                                                                             2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
  (https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
\2\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
  designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
  which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
  automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, vessel strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A
  CV associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ A reliable population estimate for the entire stock is not available. Using a sub-sample of data collected from the U.S. portion of the Bering Sea,
  an abundance estimate of 171,418 ringed seals has been calculated, but this estimate does not account for availability bias due to seals in the water
  or in the shore-fast ice zone at the time of the survey. The actual number of ringed seals in the U.S. portion of the Bering Sea is likely much
  higher. Using the Nmin based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a
  negatively biased estimate.

    As indicated above, both species (with three managed stocks) in 
table 3 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. While bowhead whales 
(Balaena mysticetus), gray whales (Eschrichtius robustus), bearded 
seals (Erignathus barbatus), spotted seals (Phoca largha), and ribbon 
seals (Histriophoca fasciata) have been documented in the area, the 
temporal and/or spatial occurrence of these

[[Page 66075]]

species is such that take is not expected to occur, and they are not 
discussed further beyond the explanation provided below.
    Due to the location of the study area (i.e., northern offshore, 
deep water), there were no calculated exposures for the bowhead whale, 
gray whale, bearded seal, spotted seal, and ribbon seal from 
quantitative modeling of acoustic sources. Bowhead and gray whales are 
closely associated with the shallow waters of the continental shelf in 
the Beaufort Sea and are unlikely to be exposed to acoustic harassment 
from this activity (Young et al., 2023). Gray whales feed primarily in 
the Beaufort Sea, Chukchi Sea, and Northwestern Bering Sea during the 
summer and fall, but migrate south to winter in Baja California lagoons 
(Young et al., 2023). Gray whales are primarily bottom feeders (Swartz 
et al., 2006) in water depths of less than 60 m (196.9 ft) (Pike, 
1962). Therefore, on the rare occasion that a gray whale does 
overwinter in the Beaufort Sea (Stafford et al., 2007), we would expect 
an overwintering individual to remain in shallow water over the 
continental shelf where it could feed. Spotted seals tend to prefer 
pack ice areas with water depths less than 200 m (656.2 ft) during the 
spring and move to coastal habitats in the summer and fall, found as 
far north as 69-72 degrees N (Muto et al., 2021). Although the study 
area includes some waters south of 72 degrees N, the acoustic sources 
with the potential to result in take of marine mammals are not found 
below that latitude and spotted seals are not expected to be exposed. 
Ribbon seals are found year-round in the Bering Sea but may seasonally 
range into the Chukchi Sea (Muto et al., 2021). The proposed action 
occurs primarily in the Beaufort Sea, outside of the core range of 
ribbon seals, thus ribbon seals are not expected to be behaviorally 
harassed. Narwhals (Monodon monoceros) are considered extralimital in 
the project area and are not expected to be encountered. As no 
harassment is expected of the bowhead whale, gray whale, spotted seal, 
bearded seal, ribbon seal, and narwhal, these species will not be 
discussed further in this proposed notice.
    The ONR utilized Conn et al. (2014) in their IHA application as an 
abundance estimate for ringed seals, which is based upon aerial 
abundance and distribution surveys conducted in the U.S. portion Bering 
Sea in 2012 (171,418 ringed seals) (Muto et al., 2021). This value is 
likely an underestimate due to the lack of accounting for availability 
bias for seals that were in the water at the time of the surveys as 
well as not including seals located within the shore-fast ice zone 
(Muto et al., 2021). Muto et al. (2021) notes that an accurate 
population estimate is likely larger by a factor of two or more. 
However, no accepted population estimate is present for Arctic ringed 
seals. Therefore, NMFS will also adopt the Conn et al. (2014) abundance 
estimate (171,418) for further analyses and discussions on this 
proposed action by ONR.
    In addition, the polar bear (Ursus maritimus) and Pacific walrus 
(Odobenus rosmarus) may be found both on sea ice and/or in the water 
within the Beaufort Sea and Chukchi Sea. These species are managed by 
the U.S. Fish and Wildlife Service rather than NMFS and, therefore, 
they are not considered further in this document.

Beluga Whale

    Beluga whales are distributed throughout seasonally ice-covered 
arctic and subarctic waters of the Northern Hemisphere (Gurevich, 
1980), and are closely associated with open leads and polynyas in ice-
covered regions (Hazard, 1988). Belugas may be either migratory or 
residential (non-migratory), depending on the population. Seasonal 
distribution is affected by ice cover, tidal conditions, access to 
prey, temperature, and human interaction (Frost et al., 1985; Hauser et 
al., 2014).
    There are five beluga whale stocks recognized within U.S. waters: 
Cook Inlet, Bristol Bay, eastern Bering Sea, eastern Chukchi Sea, and 
Beaufort Sea. Two stocks, the Beaufort Sea and eastern Chukchi Sea 
stocks, have the potential to occur in the location of this proposed 
action.
    Migratory Biologically Important Areas (BIAs) for belugas in the 
eastern Chukchi and Alaskan Beaufort Sea overlap the southern and 
western portion of the Study Area (Clarke et al., 2023). A migration 
corridor for both stocks of beluga whale includes the eastern Chukchi 
Sea through the Beaufort Sea, with the Beaufort Sea stock utilizing the 
migratory BIA in April-May and the Eastern Chukchi Sea stock utilizing 
portions of the area in November. There are also feeding BIAs for both 
stocks throughout the Arctic region (Clarke et al., 2023). During the 
winter, they can be found foraging in offshore waters associated with 
pack ice. When the sea ice melts in summer, they move to warmer river 
estuaries and coastal areas for molting and calving (Muto et al., 
2021). Annual migrations can span over thousands of kilometers. The 
residential Beaufort Sea populations participate in short distance 
movements within their range throughout the year. Based on satellite 
tags (Suydam et al., 2001; Hauser et al., 2014), there is some overlap 
in distribution with the eastern Chukchi Sea beluga whale stock.
    During the winter, eastern Chukchi Sea belugas occur in offshore 
waters associated with pack ice. In the spring, they migrate to warmer 
coastal estuaries, bays, and rivers where they may molt (Finley, 1982; 
Suydam, 2009), give birth to, and care for their calves (Sergeant and 
Brodie, 1969). Eastern Chukchi Sea belugas move into coastal areas, 
including Kasegaluk Lagoon (outside of the proposed project site), in 
late June and animals are sighted in the area until about mid-July 
(Frost and Lowry, 1990; Frost et al., 1993). Satellite tags attached to 
eastern Chukchi Sea belugas captured in Kasegaluk Lagoon during the 
summer showed these whales traveled 1,100 km (593 nm) north of the 
Alaska coastline, into the Canadian Beaufort Sea within three months 
(Suydam et al., 2001). Satellite telemetry data from 23 whales tagged 
during 1998-2007 suggest variation in movement patterns for different 
age and/or sex classes during July-September (Suydam et al., 2005). 
Adult males used deeper waters and remained there for the duration of 
the summer; all belugas that moved into the Arctic Ocean (north of 75 
degrees N) were males, and males traveled through 90 percent pack ice 
cover to reach deeper waters in the Beaufort Sea and Arctic Ocean (79-
80 degrees N) by late July/early August. Adult and immature female 
belugas remained at or near the shelf break in the south through the 
eastern Bering Strait into the northern Bering Sea, remaining north of 
Saint Lawrence Island over the winter.

Ringed Seal

    Ringed seals are the most common pinniped in the Study Area and 
have wide distribution in seasonally and permanently ice-covered waters 
of the Northern Hemisphere (North Atlantic Marine Mammal Commission, 
2004). Throughout their range, ringed seals have an affinity for ice-
covered waters and are well adapted to occupying both shore-fast and 
pack ice (Kelly, 1988). Ringed seals can be found further offshore than 
other pinnipeds since they can maintain breathing holes in ice 
thickness greater than 2 m (6.6 ft) (Smith and Stirling, 1975). The 
breathing holes are maintained by ringed seals using their sharp teeth 
and claws found on their fore flippers. They remain in contact with ice 
most of the year and use it as a platform for molting in late spring to 
early summer, for pupping and nursing in late winter to

[[Page 66076]]

early spring, and for resting at other times of the year (Muto et al., 
2018).
    Ringed seals have at least two distinct types of subnivean lairs: 
Haulout lairs and birthing lairs (Smith and Stirling, 1975). Haul-out 
lairs are typically single-chambered and offer protection from 
predators and cold weather. Birthing lairs are larger, multi-chambered 
areas that are used for pupping in addition to protection from 
predators. Ringed seals pup on both shore-fast ice as well as stable 
pack ice. Lentfer (1972) found that ringed seals north of 
Utqia[gdot]vik, Alaska, build their subnivean lairs on the pack ice 
near pressure ridges. Since subnivean lairs were found north of 
Utqia[gdot]vik, Alaska, in pack ice, they are also assumed to be found 
within the sea ice in the proposed project site. Ringed seals excavate 
subnivean lairs in drifts over their breathing holes in the ice, in 
which they rest, give birth, and nurse their pups for 5-9 weeks during 
late winter and spring (Chapskii, 1940; McLaren, 1958; Smith and 
Stirling, 1975). Ringed seals are born beginning in March but the 
majority of births occur in early April. About a month after 
parturition, mating begins in late April and early May.
    In Alaskan waters, during winter and early spring when sea ice is 
at its maximum extent, ringed seals are abundant in the northern Bering 
Sea, Norton and Kotzebue Sounds, and throughout the Chukchi and 
Beaufort seas (Frost, 1985; Kelly, 1988). Passive acoustic monitoring 
of ringed seals from a high frequency recording package deployed at a 
depth of 240 m (787 ft) in the Chukchi Sea 120 km (65 nm) north-
northwest of Utqia[gdot]vik, Alaska detected ringed seals in the area 
between mid-December and late May over the 4 year study (Jones et al., 
2014). In addition, ringed seals have been observed near and beyond the 
outer boundary of the U.S. EEZ (Beland and Ireland, 2010). During the 
spring and early summer, ringed seals may migrate north as the ice edge 
recedes and spend their summers in the open water period of the 
northern Beaufort and Chukchi Seas (Frost, 1985). Foraging-type 
movements have been recorded over the continental shelf and north of 
the continental shelf waters (Von Duyke et al., 2020). During this 
time, sub-adult ringed seals may also occur in the Arctic Ocean Basin 
(Hamilton et al., 2015; Hamilton et al., 2017).
    With the onset of fall freeze, ringed seal movements become 
increasingly restricted and seals will either move west and south with 
the advancing ice pack with many seals dispersing throughout the 
Chukchi and Bering Seas, or remaining in the Beaufort Sea (Crawford et 
al., 2012; Frost and Lowry, 1984; Harwood et al., 2012). Kelly et al. 
(2010a) tracked home ranges for ringed seals in the subnivean period 
(using shore-fast ice); the size of the home ranges varied from less 
than 1 up to 279 km\2\ (median = 0.62 km\2\ for adult males, 0.65 km\2\ 
for adult females). Most (94 percent) of the home ranges were less than 
3 km\2\ during the subnivean period (Kelly et al., 2010a). Near large 
polynyas, ringed seals maintain ranges, up to 7,000 km\2\ during winter 
and 2,100 km\2\ during spring (Born et al., 2004). Some adult ringed 
seals return to the same small home ranges they occupied during the 
previous winter (Kelly et al., 2010a). The size of winter home ranges 
can vary by up to a factor of 10 depending on the amount of fast ice; 
seal movements were more restricted during winters with extensive fast 
ice, and were much less restricted where fast ice did not form at high 
levels (Harwood et al., 2015).
    Of the five recognized subspecies of ringed seals, the Arctic 
ringed seal occurs in the Arctic Ocean and Bering Sea and is the only 
stock that occurs in U.S. waters. NMFS listed the Arctic ringed seal 
subspecies as threatened under the ESA on December 28, 2012 (77 FR 
76706), primarily due to anticipated loss of sea ice through the end of 
the 21st century. Climate change presents a major concern for the 
conservation of ringed seals due to the potential for long-term habitat 
loss and modification (Muto et al., 2021). Based upon an analysis of 
various life history features and the rapid changes that may occur in 
ringed seal habitat, ringed seals are expected to be highly sensitive 
to climate change (Laidre et al., 2008; Kelly et al., 2010b).

Critical Habitat

    Critical habitat for the ringed seal was designated in May 2022 and 
includes marine waters within one specific area in the Bering, Chukchi, 
and Beaufort Seas (87 FR 19232, April 1, 2022). Essential features 
established by NMFS for conservation of ringed seals are (1) snow-
covered sea ice habitat suitable for the formation and maintenance of 
subnivean birth lairs used for sheltering pups during whelping and 
nursing, which is defined as waters 3 m (9.8 ft) or more in depth 
(relative to Mean Lower Low Water (MLLW)) containing areas of seasonal 
land-fast (shore-fast) ice or dense, stable pack ice, that have 
undergone deformation and contain snowdrifts of sufficient depth to 
form and maintain birth lairs (typically at least 54 cm (21.3 in) 
deep); (2) sea ice habitat suitable as a platform for basking and 
molting, which is defined as areas containing sea ice of 15 percent or 
more concentration in waters 3 m (9.8 ft) or more in depth (relative to 
MLLW); and (3) primary prey resources to support Arctic ringed seals, 
which are defined to be small, often schooling, fishes, in particular 
Arctic cod (Boreogadus saida), saffron cod (Eleginus gracilis), and 
rainbow smelt (Osmerus dentex); and small crustaceans, in particular, 
shrimps and amphipods.
    The Study Area does not overlap with ringed seal critical habitat 
(87 FR 19232, April 1, 2022). However, as stated in NMFS' final rule 
for the Designation of Critical Habitat for the Arctic Subspecies of 
the Ringed Seal (87 FR 19232, April 1, 2022), the area excluded from 
the critical habitat contains one or more of the essential features of 
the Arctic ringed seal's critical habitat, therefore, even though this 
area is excluded from critical habitat designation, habitat with the 
physical and biological features essential for ringed seal conservation 
is still available to the species, although data are limited to inform 
NMFS' assessment of the relative value of this area to the conservation 
of the species. As described later and in more detail in the Potential 
Effects of Specified Activities on Marine Mammals and Their Habitat 
section, we expect minimal impacts to marine mammal habitat as a result 
of the ONR's ARA, including impacts to ringed seal sea ice habitat 
suitable as a platform for basking and molting and impacts on prey 
availability.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007) and Southall et al. (2019) recommended that marine mammals be 
divided into hearing groups based on directly measured (behavioral or 
auditory evoked potential techniques) or estimated hearing ranges 
(behavioral response data, anatomical modeling, etc.). Subsequently, 
NMFS (2018) described generalized hearing ranges for these marine 
mammal hearing groups. Generalized hearing ranges were chosen based on 
the approximately 65 dB threshold from the normalized composite 
audiograms, with the exception for lower limits for low-

[[Page 66077]]

frequency cetaceans where the lower bound was deemed to be biologically 
implausible and the lower bound from Southall et al. (2007) retained. 
Marine mammal hearing groups and their associated hearing ranges are 
provided in table 4.

                  Table 4--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
               Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen        7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,     150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true         275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 Cephalorhynchid, Lagenorhynchus cruciger
 & L. australis).
Phocid pinnipeds (PW) (underwater) (true    50 Hz to 86 kHz.
 seals).
Otariid pinnipeds (OW) (underwater) (sea    60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
\*\ Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on approximately 65 dB threshold from
  normalized composite audiogram, with the exception for lower limits
  for LF cetaceans (Southall et al., 2007) and PW pinniped
  (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al., 
2013). This division between phocid and otariid pinnipeds is now 
reflected in the updated hearing groups proposed in Southall et al. 
(2019).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take of Marine Mammals section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take of Marine Mammals section, and the Proposed Mitigation 
section, to draw conclusions regarding the likely impacts of these 
activities on the reproductive success or survivorship of individuals 
and whether those impacts are reasonably expected to, or reasonably 
likely to, adversely affect the species or stock through effects on 
annual rates of recruitment or survival.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far (ANSI, 1995). The sound level of an area is 
defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., waves, wind, 
precipitation, earthquakes, ice, atmospheric sound), biological (e.g., 
sounds produced by marine mammals, fish, and invertebrates), and 
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activities may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    Active acoustic sources and icebreaking, if necessary, are proposed 
for use in the Study Area. The sounds produced by these activities fall 
into one of two general sound types: impulsive and non-impulsive. 
Impulsive sounds (e.g., ice explosions, gunshots, sonic booms, impact 
pile driving) are typically transient, brief (less than 1 second), 
broadband, and consist of high peak sound pressure with rapid rise time 
and rapid decay (ANSI, 1986; NIOSH, 1998; NMFS, 2018). Non-impulsive 
sounds (e.g., aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, pile cutting, diamond wire sawing, 
and active sonar systems) can be broadband, narrowband, or tonal, brief 
or prolonged (continuous or intermittent), and typically do not have 
the high peak sound pressure with raid rise/decay time that impulsive 
sounds do (ANSI, 1986; NIOSH, 1998; NMFS, 2018). The distinction 
between these two sound types is important because they have differing 
potential to cause physical effects, particularly with regard to 
hearing (e.g., Ward, 1997; Southall et al., 2007).
    The likely or possible impacts of the ONR's proposed action on 
marine mammals involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of vessels, equipment, and personnel (e.g., icebreaking 
impacts, vessel and in-water vehicle strike, and bottom disturbance); 
however, any impacts to marine mammals are expected to primarily be 
acoustic in nature (e.g., non-impulsive acoustic sources, noise from 
icebreaking vessel (``icebreaking noise''), and vessel noise).

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from active acoustic sources and noise from icebreaking is 
the means by which marine mammals may be harassed from the ONR's 
specified activity. In general, animals exposed to natural or 
anthropogenic sound may experience behavioral, physiological, and/or 
physical effects, ranging in magnitude from none to severe (Southall et 
al., 2007). In general, exposure to pile driving noise has the 
potential to result in behavioral reactions (e.g., avoidance, temporary 
cessation of foraging and vocalizing, changes in dive behavior) and, in 
limited cases, an auditory threshold shift (TS). Exposure to 
anthropogenic noise can also lead to non-observable physiological 
responses such an increase in stress hormones. Additional noise in a 
marine mammal's habitat can mask acoustic cues used by marine mammals 
to carry out daily functions such as communication and predator and 
prey detection. The effects

[[Page 66078]]

of pile driving noise on marine mammals are dependent on several 
factors, including, but not limited to, sound type (e.g., impulsive 
versus non-impulsive), the species, age and sex class (e.g., adult male 
versus mother with calf), duration of exposure, the distance between 
the pile and the animal, received levels, behavior at time of exposure, 
and previous history with exposure (Wartzok et al., 2004; Southall et 
al., 2007). Here we discuss physical auditory effects (i.e., TS) 
followed by behavioral effects and potential impacts on habitat.
    NMFS defines a noise-induced TS as a change, usually an increase, 
in the threshold of audibility at a specified frequency or portion of 
an individual's hearing range above a previously established reference 
level (NMFS, 2018). The amount of TS is customarily expressed in dB and 
TS can be permanent or temporary. As described in NMFS (2018), there 
are numerous factors to consider when examining the consequence of TS, 
including, but not limited to, the signal temporal pattern (e.g., 
impulsive or non-impulsive), likelihood an individual would be exposed 
for a long enough duration or to a high enough level to induce a TS, 
the magnitude of the TS, time to recovery (seconds to minutes or hours 
to days), the frequency range of the exposure (i.e., spectral content), 
the hearing and vocalization frequency range of the exposed species 
relative to the signal's frequency spectrum (i.e., how animal uses 
sound within the frequency band of the signal) (Kastelein et al., 
2014), and the overlap between the animal and the source (e.g., 
spatial, temporal, and spectral).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Available data 
from humans and other terrestrial mammals indicate that a 40 dB TS 
approximates PTS onset (see Ward et al., 1958; Ward et al., 1959; Ward, 
1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson 
et al., 2008). PTS levels for marine mammals are estimates as, with the 
exception of a single study unintentionally inducing PTS in a harbor 
seal (e.g., Kastak et al., 2008), there are no empirical data measuring 
PTS in marine mammals largely due to the fact that, for various ethical 
reasons, experiments involving anthropogenic noise exposure at levels 
inducing PTS are not typically pursued or authorized (NMFS, 2018).
    Temporary Threshold Shift (TTS)--TTS is a temporary, reversible 
increase in the threshold of audibility at a specified frequency or 
portion of an individual's hearing range above a previously established 
reference level (NMFS, 2018). Based on data from cetacean TTS 
measurements (see Southall et al., 2007), a TTS of 6 dB is considered 
the minimum TS clearly larger than any day-to-day or session-to-session 
variation in a subject's normal hearing ability (Finneran et al., 2000; 
Schlundt et al., 2000; Finneran et al., 2002). As described in Finneran 
(2016), marine mammal studies have shown the amount of TTS increases 
with cumulative sound exposure level (SELcum) in an 
accelerating fashion: At low exposures with lower SELcum, 
the amount of TTS is typically small and the growth curves have shallow 
slopes. At exposures with higher SELcum, the growth curves 
become steeper and approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in the 
Auditory Masking section). For example, a marine mammal may be able to 
readily compensate for a brief, relatively small amount of TTS in a 
non-critical frequency range that takes place during a time when the 
animal is traveling through the open ocean, where ambient noise is 
lower and there are not as many competing sounds present. 
Alternatively, a larger amount and longer duration of TTS sustained 
during time when communication is critical for successful mother/calf 
interactions could have more serious impacts. We note that reduced 
hearing sensitivity as a simple function of aging has been observed in 
marine mammals, as well as humans and other taxa (Southall et al., 
2007), so we can infer that strategies exist for coping with this 
condition to some degree, though likely not without cost.
    Many studies have examined noise-induced hearing loss in marine 
mammals (see Finneran, 2015; Southall et al., 2019 for summaries). TTS 
is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter et al., 1966). While experiencing TTS, the 
hearing threshold rises, and a sound must be at a higher level in order 
to be heard. In terrestrial and marine mammals, TTS can last from 
minutes or hours to days (in cases of strong TTS). In many cases, 
hearing sensitivity recovers rapidly after exposure to the sound ends. 
For cetaceans, published data on the onset of TTS are limited to 
captive bottlenose dolphin (Tursiops truncatus), beluga whale, harbor 
porpoise (Phocoena phocoena), and Yangtze finless porpoise (Neophocoena 
asiaeorientalis) (Southall et al., 2019). For pinnipeds in water, 
measurements of TTS are limited to harbor seals (Phoca vitulina), 
elephant seals (Mirounga angustirostris), bearded seals, and California 
sea lions (Zalophus californianus) (Kastak et al., 1999; Kastak et al., 
2008; Kastelein et al., 2020b; Reichmuth et al., 2013; Sills et al., 
2020). TTS was not observed in spotted and ringed seals exposed to 
single airgun impulse sounds at levels matching previous predictions of 
TTS onset (Reichmuth et al., 2016). These studies examine hearing 
thresholds measured in marine mammals before and after exposure to 
intense or long-duration sound exposure. The difference between the 
pre-exposure and post-exposure thresholds can be used to determine the 
amount of threshold shift at various post-exposure times.
    The amount and onset of TTS depends on the exposure frequency. 
Sounds at low frequencies, well below the region of best sensitivity 
for a species or hearing group, are less hazardous than those at higher 
frequencies, near the region of best sensitivity (Finneran and 
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al., 2019a; Kastelein et al., 2019b; Kastelein et 
al., 2020a; Kastelein et al., 2020b). Note that in general, harbor 
seals and harbor porpoises have a lower TTS onset than other measured 
pinniped or cetacean species (Finneran, 2015). In addition, TTS can 
accumulate across multiple exposures but the resulting TTS will be less 
than the TTS from a single, continuous exposure with the same SEL 
(Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014; 
Kastelein et al., 2015). This means that TTS predictions based on the 
total SELcum will overestimate the amount of TTS from 
intermittent exposures, such as sonars and impulsive sources. 
Nachtigall et al. (2018) describe measurements of hearing sensitivity 
of multiple odontocete species (bottlenose dolphin, harbor porpoise, 
beluga whale, and false killer whale (Pseudorca crassidens)) when a 
relatively loud sound was preceded by a warning

[[Page 66079]]

sound. These captive animals were shown to reduce hearing sensitivity 
when warned of an impending intense sound. Based on these experimental 
observations of captive animals, the authors suggest that wild animals 
may dampen their hearing during prolonged exposures or if conditioned 
to anticipate intense sounds. Another study showed that echolocating 
animals (including odontocetes) might have anatomical specializations 
that might allow for conditioned hearing reduction and filtering of 
low-frequency ambient noise, including increased stiffness and control 
of middle ear structures and placement of inner ear structures (Ketten 
et al., 2021). Data available on noise-induced hearing loss for 
mysticetes are currently lacking (NMFS, 2018). Additionally, the 
existing marine mammal TTS data come from a limited number of 
individuals within these species.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several decibels above that inducing mild TTS (e.g., a 40-dB threshold 
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while 
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007; 
Southall et al., 2019). Based on data from terrestrial mammals, a 
precautionary assumption is that the PTS thresholds for impulsive 
sounds (such as impact pile driving pulses as received close to the 
source) are at least 6 dB higher than the TTS threshold on a peak-
pressure basis and PTS cumulative sound exposure level thresholds are 
15 to 20 dB higher than TTS cumulative sound exposure level thresholds 
(Southall et al., 2007; Southall et al., 2019). Given the higher level 
of sound or longer exposure duration necessary to cause PTS as compared 
with TTS, it is considerably less likely that PTS could occur.
    Activities for this project include active acoustics, equipment 
deployment and recovery, and, potentially, icebreaking. For the 
proposed action, these activities would not occur at the same time and 
there would likely be pauses in activities producing the sound during 
each day. Given these pauses and that many marine mammals are likely 
moving through the Study Area and not remaining for extended periods of 
time, the potential for TS declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
drilling also has the potential to behaviorally disturb marine mammals. 
Generally speaking, NMFS considers a behavioral disturbance that rises 
to the level of harassment under the MMPA a non-minor response--in 
other words, not every response qualifies as behavioral disturbance, 
and for responses that do, those of a higher level, or accrued across a 
longer duration, have the potential to affect foraging, reproduction, 
or survival. Behavioral disturbance may include a variety of effects, 
including subtle changes in behavior (e.g., minor or brief avoidance of 
an area or changes in vocalizations), more conspicuous changes in 
similar behavioral activities, and more sustained and/or potentially 
severe reactions, such as displacement from or abandonment of high-
quality habitat. Behavioral responses may include changing durations of 
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral 
activities (such as socializing or feeding); eliciting a visible 
startle response or aggressive behavior (such as tail/fin slapping or 
jaw clapping); avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound 
are highly variable and context-specific and any reactions depend on 
numerous intrinsic and extrinsic factors (e.g., species, state of 
maturity, experience, current activity, reproductive state, auditory 
sensitivity, time of day), as well as the interplay between factors 
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al., 
2007; Southall et al., 2019; Weilgart, 2007; Archer et al., 2010). 
Behavioral reactions can vary not only among individuals but also 
within an individual, depending on previous experience with a sound 
source, context, and numerous other factors (Ellison et al., 2012), and 
can vary depending on characteristics associated with the sound source 
(e.g., whether it is moving or stationary, number of sources, distance 
from the source). In general, pinnipeds seem more tolerant of, or at 
least habituate more quickly to, potentially disturbing underwater 
sound than do cetaceans, and generally seem to be less responsive to 
exposure to industrial sound than most cetaceans. Please see Appendices 
B and C of Southall et al. (2007) and Gomez et al. (2016) for reviews 
of studies involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2004). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; Wartzok et al., 2004; NRC, 2005). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (e.g., seismic airguns) have been varied but 
often consist of avoidance behavior or other behavioral changes 
(Richardson et al., 1995; Morton and Symonds, 2002; Nowacek et al., 
2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Nowacek et al., 2004; Goldbogen et al., 2013a; 
Goldbogen et al., 2013b). Variations in dive behavior may reflect 
interruptions

[[Page 66080]]

in biologically significant activities (e.g., foraging) or they may be 
of little biological significance. The impact of an alteration to dive 
behavior resulting from an acoustic exposure depends on what the animal 
is doing at the time of the exposure and the type and magnitude of the 
response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2005; Kastelein et al., 2006). 
For example, harbor porpoise' respiration rate increased in response to 
pile driving sounds at and above a received broadband SPL of 136 dB 
(zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike: 127 dB re 1 
[mu]Pa\2\-s) (Kastelein et al., 2013).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004), 
respectively, while North Atlantic right whales (Eubalaena glacialis) 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). Avoidance may be short-
term, with animals returning to the area once the noise has ceased 
(e.g., Bowles et al., 1994; Morton and Symonds, 2002). Longer-term 
displacement is possible, however, which may lead to changes in 
abundance or distribution patterns of the affected species in the 
affected region if habituation to the presence of the sound does not 
occur (e.g., Blackwell et al., 2004; Bejder et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996; Bowers et al., 2018). The result of a flight response 
could range from brief, temporary exertion and displacement from the 
area where the signal provokes flight to, in extreme cases, marine 
mammal strandings (Evans and England, 2001). However, it should be 
noted that response to a perceived predator does not necessarily invoke 
flight (Ford and Reeves, 2008), and whether individuals are solitary or 
in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fishes and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Purser and Radford, 2011; Fritz et al., 2002). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Daan et 
al., 1996; Bradshaw et al., 1998). However, Ridgway et al. (2006) 
reported that increased vigilance in bottlenose dolphins exposed to 
sound over a 5-day period did not cause any sleep deprivation or stress 
effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than 1 day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive (i.e., meaningful) behavioral reactions and multi-day 
anthropogenic activities. For example, just because an activity lasts 
for multiple days does not necessarily mean that individual animals are 
either exposed to activity-related stressors for multiple days or, 
further, exposed in a manner resulting in sustained multi-day 
substantive behavioral responses.
    Behavioral Responses to Icebreaking Noise--Ringed seals on pack ice 
showed various behaviors when approached by an icebreaking vessel. A 
majority of seals dove underwater when the ship was within 0.93 km (0.5 
nm) while others remained on the ice. However, as icebreaking vessels 
came closer to the seals, most dove underwater. Ringed seals have also 
been observed foraging in the wake of an icebreaking vessel (Richardson 
et al., 1995) and may have preferentially established breathing holes 
in the ship tracks after the ice-breaker moved through the area. 
Previous observations and studies using icebreaking ships provide a 
greater understanding in how seal behavior may be affected by a vessel 
transiting through the area.
    Adult ringed seals spend up to 20 percent of the time in subnivean 
lairs during the winter season (Kelly et al.,

[[Page 66081]]

2010a). Ringed seal pups spend about 50 percent of their time in the 
lair during the nursing period (Lydersen and Hammill, 1993). During the 
warm season ringed seals haul out on the ice. In a study of ringed seal 
haul out activity by Born et al. (2002), ringed seals spent 25-57 
percent of their time hauled out in June, which is during their molting 
season. Ringed seal lairs are typically used by individual seals 
(haulout lairs) or by a mother with a pup (birthing lairs); large lairs 
used by many seals for hauling out are rare (Smith and Stirling, 1975). 
If the non-impulsive acoustic transmissions are heard and are perceived 
as a threat, ringed seals within subnivean lairs could react to the 
sound in a similar fashion to their reaction to other threats, such as 
polar bears (their primary predators), although the type of sound would 
be novel to them. Responses of ringed seals to a variety of human-
induced sounds (e.g., helicopter noise, snowmobiles, dogs, people, and 
seismic activity) have been variable; some seals entered the water and 
some seals remained in the lair. However, in all instances in which 
observed seals departed lairs in response to noise disturbance, they 
subsequently reoccupied the lair (Kelly et al., 1988).
    Ringed seal mothers have a strong bond with their pups and may 
physically move their pups from the birth lair to an alternate lair to 
avoid predation, sometimes risking their lives to defend their pups 
from potential predators. If a ringed seal mother perceives the 
proposed acoustic sources as a threat, the network of multiple birth 
and haulout lairs allows the mother and pup to move to a new lair 
(Smith and Stirling, 1975; Smith and Hammill, 1981). The acoustic 
sources from this proposed action are not likely to impede a ringed 
seal from finding a breathing hole or lair, as captive seals have been 
found to primarily use vision to locate breathing holes and no effect 
to ringed seal vision would occur from the acoustic disturbance (Elsner 
et al., 1989; Wartzok et al., 1992). It is anticipated that a ringed 
seal would be able to relocate to a different breathing hole relatively 
easily without impacting their normal behavior patterns.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Selye, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced vessel traffic in the Bay of Fundy 
was associated with decreased stress in North Atlantic right whales. 
These and other studies lead to a reasonable expectation that some 
marine mammals will experience physiological stress responses upon 
exposure to acoustic stressors and that it is possible that some of 
these would be classified as ``distress.'' In addition, any animal 
experiencing TTS would likely also experience stress responses (NRC, 
2003), however, distress is an unlikely result of the proposed project 
based on observations of marine mammals during previous, similar 
projects in the region.
    Auditory Masking--Since many marine mammals rely on sound to find 
prey, moderate social interactions, and facilitate mating (Tyack, 
2008), noise from anthropogenic sound sources can interfere with these 
functions, but only if the noise spectrum overlaps with the hearing 
sensitivity of the receiving marine mammal (Southall et al., 2007; 
Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive, 
though not high-intensity, noise could cause masking at particular 
frequencies for marine mammals that utilize sound for vital biological 
functions (Clark et al., 2009). Acoustic masking is when other noises 
such as from human sources interfere with an animal's ability to 
detect, recognize, or discriminate between acoustic signals of interest 
(e.g., those used for intraspecific communication and social 
interactions, prey detection, predator avoidance, navigation) 
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain 
circumstances, marine mammals whose acoustical sensors or environment 
are being severely masked could also be impaired from maximizing their 
performance fitness in survival and reproduction. The ability of a 
noise source to mask biologically important sounds depends on the 
characteristics of both the noise source and the signal of interest 
(e.g., signal-to-noise ratio, temporal variability, direction), in 
relation to each other and to an animal's hearing abilities (e.g., 
sensitivity, frequency range, critical ratios, frequency 
discrimination, directional discrimination, age or TTS hearing loss), 
and existing ambient noise and propagation conditions (Hotchkin and 
Parks, 2013).
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is human-made, it may be considered 
harassment when disrupting or altering critical behaviors. It is 
important to distinguish TTS and PTS, which persist after the sound 
exposure, from masking, which occurs during the sound exposure. Because 
masking (without resulting in TS) is not associated with abnormal 
physiological function, it is not considered a physiological effect, 
but rather a potential behavioral effect

[[Page 66082]]

(though not necessarily one that would be associated with harassment).
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Hotchkin and Parks, 2013). Masking can be 
tested directly in captive species (e.g., Erbe, 2008), but in wild 
populations it must be either modeled or inferred from evidence of 
masking compensation. There are few studies addressing real-world 
masking sounds likely to be experienced by marine mammals in the wild 
(e.g., Branstetter et al., 2013).
    Marine mammals at or near the proposed project site may be exposed 
to anthropogenic noise which may be a source of masking. Vocalization 
changes may result from a need to compete with an increase in 
background noise and include increasing the source level, modifying the 
frequency, increasing the call repetition rate of vocalizations, or 
ceasing to vocalize in the presence of increased noise (Hotchkin and 
Parks, 2013). For example, in response to loud noise, beluga whales may 
shift the frequency of their echolocation clicks to prevent masking by 
anthropogenic noise (Eickmeier and Vallarta, 2023).
    Masking is more likely to occur in the presence of broadband, 
relatively continuous noise sources such as vibratory pile driving. 
Energy distribution of pile driving covers a broad frequency spectrum, 
and sound from pile driving would be within the audible range of 
pinnipeds and cetaceans present in the proposed action area. While 
icebreaking during the ONR's proposed action may mask some acoustic 
signals that are relevant to the daily behavior of marine mammals, the 
short-term duration (up to 8 days) and limited areas affected make it 
very unlikely that the fitness of individual marine mammals would be 
impacted.
    Potential Effects on Prey--The marine mammal species in the Study 
Area feed on marine invertebrates and fish. Studies of sound energy 
effects on invertebrates are few, and primarily identify behavioral 
responses. It is expected that most marine invertebrates would not 
sense the frequencies of the acoustic transmissions from the acoustic 
sources associated with the proposed action. Although acoustic sources 
used during the proposed action may briefly impact individuals, 
intermittent exposures to non-impulsive acoustic sources are not 
expected to impact survival, growth, recruitment, or reproduction of 
widespread marine invertebrate populations.
    The fish species residing in the study area include those that are 
closely associated with the deep ocean habitat of the Beaufort Sea. 
Nearly 250 marine fish species have been described in the Arctic, 
excluding the larger parts of the sub-Arctic Bering, Barents, and 
Norwegian Seas (Mecklenburg et al., 2011). However, only about 30 are 
known to occur in the Arctic waters of the Beaufort Sea (Christiansen 
and Reist, 2013). Although hearing capability data only exist for fewer 
than 100 of the 32,000 named fish species, current data suggest that 
most species of fish detect sounds from 50 to 100 Hz, with few fish 
hearing sounds above 4 kHz (Popper, 2008). It is believed that most 
fish have the best hearing sensitivity from 100 to 400 Hz (Popper, 
2003). Fish species in the study area are expected to hear the low-
frequency sources associated with the proposed action, but most are not 
expected to detect sound from the mid-frequency sources. Human 
generated sound could alter the behavior of a fish in a manner than 
would affect its way of living, such as where it tries to locate food 
or how well it could find a mate. Behavioral responses to loud noise 
could include a startle response, such as the fish swimming away from 
the source, the fish ``freezing'' and staying in place, or scattering 
(Popper, 2003). Misund (1997) found that fish ahead of a ship showed 
avoidance reactions at ranges of 49-149 m (160-489 ft). Avoidance 
behavior of vessels, vertically or horizontally in the water column, 
has been reported for cod and herring, and was attributed to vessel 
noise. While acoustic sources associated with the proposed action may 
influence the behavior of some fish species, other fish species may be 
equally unresponsive. Overall effects to fish from the proposed action 
would be localized, temporary, and infrequent.
    Effects to Physical and Foraging Habitat--Ringed seals haul out on 
pack ice during the spring and summer to molt (Reeves et al., 2002; 
Born et al., 2002). Additionally, some studies suggested that ringed 
seals might preferentially establish breathing holes in ship tracks 
after vessels move through the area (Alliston, 1980; Alliston, 1981). 
The amount of ice habitat disturbed by activities is small relative to 
the amount of overall habitat available and there will be no permanent 
or longer-term loss or modification of physical ice habitat used by 
ringed seals. Vessel movement would have minimal effect on physical 
beluga habitat as beluga habitat is solely within the water column. 
Furthermore, the deployed sources that would remain in use after the 
vessels have left the survey area have low duty cycles and lower source 
levels, and any impacts to the acoustic habitat of marine mammals would 
be minimal.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through the IHA, which will inform NMFS' 
consideration of the negligible impact determinations and impacts on 
subsistence uses.
    Harassment is the only type of take expected to result from these 
activities. For this military readiness activity, the MMPA defines 
``harassment'' as (i) Any act that injures or has the significant 
potential to injure a marine mammal or marine mammal stock in the wild 
(Level A harassment); or (ii) Any act that disturbs or is likely to 
disturb a marine mammal or marine mammal stock in the wild by causing 
disruption of natural behavioral patterns, including, but not limited 
to, migration, surfacing, nursing, breeding, feeding, or sheltering, to 
a point where the behavioral patterns are abandoned or significantly 
altered (Level B harassment).
    Authorized takes would be by Level B harassment only, in the form 
of direct behavioral disturbances and/or TTS for individual marine 
mammals resulting from exposure to active acoustic transmissions and 
icebreaking. Based on the nature of the activity, Level A harassment is 
neither anticipated nor proposed to be authorized.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds

[[Page 66083]]

above which NMFS believes the best available science indicates marine 
mammals will be behaviorally harassed or incur some degree of permanent 
hearing impairment; (2) the area or volume of water that will be 
ensonified above these levels in a day; (3) the density or occurrence 
of marine mammals within these ensonified areas; and, (4) the number of 
days of activities. We note that while these factors can contribute to 
a basic calculation to provide an initial prediction of potential 
takes, additional information that can qualitatively inform take 
estimates is also sometimes available (e.g., previous monitoring 
results or average group size). Below, we describe the factors 
considered here in more detail and present the proposed take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment). Thresholds have also been developed identifying the 
received level of in-air sound above which exposed pinnipeds would 
likely be behaviorally harassed.
Level B Harassment
    Though significantly driven by received level, the onset of 
behavioral disturbance from anthropogenic noise exposure is also 
informed to varying degrees by other factors related to the source or 
exposure context (e.g., frequency, predictability, duty cycle, duration 
of the exposure, signal-to-noise ratio, distance to the source), the 
environment (e.g., bathymetry, other noises in the area, predators in 
the area), and the receiving animals (hearing, motivation, experience, 
demography, life stage, depth) and can be difficult to predict (e.g., 
Southall et al., 2007; Southall et al., 2021; Ellison et al., 2012). 
Based on what the available science indicates and the practical need to 
use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB re 1 [mu]Pa 
for continuous (e.g., vibratory pile driving, drilling) and above RMS 
SPL 160 dB re 1 [mu]Pa for non-explosive impulsive (e.g., seismic 
airguns) or intermittent (e.g., scientific sonar) sources. Generally 
speaking, Level B harassment estimates based on these behavioral 
harassment thresholds are expected to include any likely takes by TTS 
as, in most cases, the likelihood of TTS occurs at distances from the 
source less than those at which behavioral harassment is likely. TTS of 
a sufficient degree can manifest as behavioral harassment, as reduced 
hearing sensitivity and the potential reduced opportunities to detect 
important signals (conspecific communication, predators, prey) may 
result in changes in behavior patterns that would not otherwise occur.
    In this case, NMFS is proposing to adopt the ONR's approach to 
estimating incidental take by Level B harassment from the active 
acoustic sources for this action, which includes use of dose response 
functions. The ONR's dose response functions were developed to estimate 
take from sonar and similar transducers, but are not applicable to 
icebreaking. Multi-year research efforts have conducted sonar exposure 
studies for odontocetes and mysticetes (Miller et al., 2012; Sivle et 
al., 2012). Several studies with captive animals have provided data 
under controlled circumstances for odontocetes and pinnipeds (Houser et 
al., 2013b; Houser et al., 2013a). Moretti et al. (2014) published a 
beaked whale dose-response curve based on passive acoustic monitoring 
of beaked whales during U.S. Navy training activity at Atlantic 
Underwater Test and Evaluation Center during actual Anti-Submarine 
Warfare exercises. This information necessitated the update of the 
behavioral response criteria for the U.S. Navy's environmental 
analyses.
    Southall et al. (2007), and more recently (Southall et al., 2019), 
synthesized data from many past behavioral studies and observations to 
determine the likelihood of behavioral reactions at specific sound 
levels. While in general, the louder the sound source the more intense 
the behavioral response, it was clear that the proximity of a sound 
source and the animal's experience, motivation, and conditioning were 
also critical factors influencing the response (Southall et al., 2007; 
Southall et al., 2019). After examining all of the available data, the 
authors felt that the derivation of thresholds for behavioral response 
based solely on exposure level was not supported because context of the 
animal at the time of sound exposure was an important factor in 
estimating response. Nonetheless, in some conditions, consistent 
avoidance reactions were noted at higher sound levels depending on the 
marine mammal species or group allowing conclusions to be drawn. Phocid 
seals showed avoidance reactions at or below 190 dB re 1 [mu]Pa at 1 m; 
thus, seals may actually receive levels adequate to produce TTS before 
avoiding the source.
    Odontocete behavioral criteria for non-impulsive sources were 
updated based on controlled exposure studies for dolphins and sea 
mammals, sonar, and safety (3S) studies where odontocete behavioral 
responses were reported after exposure to sonar (Miller et al., 2011; 
Miller et al., 2012; Antunes et al., 2014; Miller et al., 2014; Houser 
et al., 2013b). For the 3S study, the sonar outputs included 1-2 kHz 
up- and down-sweeps and 6-7 kHz up-sweeps; source levels were ramped up 
from 152-158 dB re 1 [mu]Pa to a maximum of 198-214 re 1 [mu]Pa at 1 m. 
Sonar signals were ramped up over several pings while the vessel 
approached the mammals. The study did include some control passes of 
ships with the sonar off to discern the behavioral responses of the 
mammals to vessel presence alone versus active sonar.
    The controlled exposure studies included exposing the Navy's 
trained bottlenose dolphins to mid-frequency sonar while they were in a 
pen. Mid-frequency sonar was played at six different exposure levels 
from 125-185 dB re 1 [mu]Pa (RMS). The behavioral response function for 
odontocetes resulting from the studies described above has a 50 percent 
probability of response at 157 dB re 1 [mu]Pa. Additionally, distance 
cutoffs (20 km for MF cetaceans) were applied to exclude exposures 
beyond which the potential of significant behavioral responses is 
considered to be unlikely.
    The pinniped behavioral threshold was updated based on controlled 
exposure experiments on the following captive animals: hooded seal 
(Cystophora cristata), gray seal (Halichoerus grypus), and California 
sea lion (G[ouml]tz et al., 2010; Houser et al., 2013a; Kvadsheim et 
al., 2010). Hooded seals were exposed to increasing levels of sonar 
until an avoidance response was observed, while the grey seals were 
exposed first to a single received level multiple times, then an 
increasing received level. Each individual California sea lion was 
exposed to the same received level ten times. These exposure sessions 
were combined into a single response value, with an overall response 
assumed if an animal responded in any single session. The resulting 
behavioral response function for pinnipeds has a 50 percent probability 
of response at 166 dB re 1

[[Page 66084]]

[mu]Pa. Additionally, distance cutoffs (10 km for pinnipeds) were 
applied to exclude exposures beyond which the potential of significant 
behavioral responses is considered unlikely. For additional information 
regarding marine mammal thresholds for PTS and TTS onset, please see 
NMFS (2018) and table 6.
    Empirical evidence has not shown responses to non-impulsive 
acoustic sources that would constitute take beyond a few km from a non-
impulsive acoustic source, which is why NMFS and the Navy 
conservatively set distance cutoffs for pinnipeds and mid-frequency 
cetaceans (U.S. Department of the Navy, 2017a). The cutoff distances 
for fixed sources are different from those for moving sources, as they 
are treated as individual sources in ONR's modeling given that the 
distance between them is significantly greater than the range to which 
environmental effects can occur. Fixed source cutoff distances used 
were 5 km (2.7 nm) for pinnipeds and 10 km (5.4 nm) for beluga whales 
(table 5). As some of the on-site drifting sources could come closer 
together, the drifting source cutoffs applied were 10 km (5.4 nm) for 
pinnipeds and 20 km (10.8 nm) for beluga whales (table 5). Regardless 
of the received level at that distance, take is not estimated to occur 
beyond these cutoff distances. Range to thresholds were calculated for 
the noise associated with icebreaking in the study area. These all fall 
within the same cutoff distances as non-impulsive acoustic sources; 
range to behavioral threshold for both beluga whales and ringed seal 
were under 5 km (2.7 nm), and range to TTS threshold for both under 15 
m (49.2 ft) (table 5).

                         Table 5--Cutoff Distances and Acoustic Thresholds Identifying the Onset of Behavioral Disturbance, TTS, and PTS for Non-Impulsive Sound Sources
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Fixed source       Drifting source       Behavioral      Icebreaking source      Behavioral
                                                          behavioral          behavioral        criteria: Non-        behavioral           criteria:         Physiological       Physiological
          Hearing group                 Species        threshold cutoff    threshold cutoff   impulsive acoustic   threshold cutoff       icebreaking       criteria: onset     criteria: onset
                                                         distance \a\        distance \a\           sources         distance \a b\          sources               TTS                 PTS
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-frequency cetaceans.........  Beluga whale......  10 km (5.4 nm)....  20 km (10.8 nm)...  Mid-frequency BRF   5 km (2.7 nm).....  120 dB re 1         178 dB SELcum.....  198 dB SELcum.
                                                                                               dose-response                           [micro]Pa step
                                                                                               function *.                             function.
Phocidae (in water).............  Ringed seal.......  5 km (2.7 nm).....  10 km (5.4 nm)....  Pinniped dose-      5 km (2.7 nm).....  120 dB re 1         181 dB SELcum.....  201 dB SELcum.
                                                                                               response function                       [micro]Pa step
                                                                                               *.                                      function.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: The threshold values provided are assumed for when the source is within the animal's best hearing sensitivity. The exact threshold varies based on the overlap of the source and the
  frequency weighting (see figure 6-1 in IHA application).
\a\ Take is not estimated to occur beyond these cutoff distances, regardless of the received level.
\b\ Range to TTS threshold for both hearing groups for the noise associated with icebreaking in the Study Area is under 15 m (49.2 ft).

Level A Harassment
    NMFS' Technical Guidance for Assessing the Effects of Anthropogenic 
Sound on Marine Mammal Hearing (Version 2.0) (Technical Guidance, 2018) 
identifies dual criteria to assess auditory injury (Level A harassment) 
to five different marine mammal groups (based on hearing sensitivity) 
as a result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). The ONR's proposed action includes the 
use of non-impulsive (active sonar and icebreaking) sources; however, 
Level A harassment is not expected as a result of the proposed 
activities based on modeling, as described below, nor is it proposed to 
be authorized by NMFS.
    These thresholds are provided in the table below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance, which may be accessed at: 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 6--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1 [mu]Pa\2\s. In this table, thresholds are abbreviated to reflect American National
  Standards Institute (ANSI) standards. However, peak sound pressure is defined by ANSI as incorporating
  frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
  being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
  designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
  that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
  exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
  is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.


[[Page 66085]]

Quantitative Modeling

    The Navy performed a quantitative analysis to estimate the number 
of marine mammals likely to be exposed to underwater acoustic 
transmissions above the previously described threshold criteria during 
the proposed action. Inputs to the quantitative analysis included 
marine mammal density estimates obtained from the Kaschner et al. 
(2006) habitat suitability model and (Ca[ntilde]adas et al., 2020), 
marine mammal depth occurrence (U.S. Department of the Navy, 2017b), 
oceanographic and mammal hearing data, and criteria and thresholds for 
levels of potential effects. The quantitative analysis consists of 
computer modeled estimates and a post-model analysis to determine the 
number of potential animal exposures. The model calculates sound energy 
propagation from the proposed non-impulsive acoustic sources, the sound 
received by animat (virtual animal) dosimeters representing marine 
mammals distributed in the area around the modeled activity, and 
whether the sound received by animats exceeds the thresholds for 
effects.
    The Navy developed a set of software tools and compiled data for 
estimating acoustic effects on marine mammals without consideration of 
behavioral avoidance or mitigation. These tools and data sets serve as 
integral components of the Navy Acoustic Effects Model (NAEMO). In 
NAEMO, animats are distributed non-uniformly based on species-specific 
density, depth distribution, and group size information and animats 
record energy received at their location in the water column. A fully 
three-dimensional environment is used for calculating sound propagation 
and animat exposure in NAEMO. Site-specific bathymetry, sound speed 
profiles, wind speed, and bottom properties are incorporated into the 
propagation modeling process. NAEMO calculates the likely propagation 
for various levels of energy (sound or pressure) resulting from each 
source used during the training event.
    NAEMO then records the energy received by each animat within the 
energy footprint of the event and calculates the number of animats 
having received levels of energy exposures that fall within defined 
impact thresholds. Predicted effects on the animats within a scenario 
are then tallied and the highest order effect (based on severity of 
criteria; e.g., PTS over TTS) predicted for a given animat is assumed. 
Each scenario, or each 24-hour period for scenarios lasting greater 
than 24 hours is independent of all others, and therefore, the same 
individual marine mammal (as represented by an animat in the model 
environment) could be impacted during each independent scenario or 24-
hour period. In few instances, although the activities themselves all 
occur within the proposed study location, sound may propagate beyond 
the boundary of the study area. Any exposures occurring outside the 
boundary of the study area are counted as if they occurred within the 
study area boundary. NAEMO provides the initial estimated impacts on 
marine species with a static horizontal distribution (i.e., animats in 
the model environment do not move horizontally).
    There are limitations to the data used in the acoustic effects 
model, and the results must be interpreted within this context. While 
the best available data and appropriate input assumptions have been 
used in the modeling, when there is a lack of definitive data to 
support an aspect of the modeling, conservative modeling assumptions 
have been chosen (i.e., assumptions that may result in an overestimate 
of acoustic exposures):
     Animats are modeled as being underwater, stationary, and 
facing the source and therefore always predicted to receive the maximum 
potential sound level at a given location (i.e., no porpoising or 
pinnipeds' heads above water);
     Animats do not move horizontally (but change their 
position vertically within the water column), which may overestimate 
physiological effects such as hearing loss, especially for slow moving 
or stationary sound sources in the model;
     Animats are stationary horizontally and therefore do not 
avoid the sound source, unlike in the wild where animals would most 
often avoid exposures at higher sound levels, especially those 
exposures that may result in PTS;
     Multiple exposures within any 24-hour period are 
considered one continuous exposure for the purposes of calculating 
potential threshold shift, because there are not sufficient data to 
estimate a hearing recovery function for the time between exposures; 
and
     Mitigation measures were not considered in the model. In 
reality, sound-producing activities would be reduced, stopped, or 
delayed if marine mammals are detected by visual monitoring.
    Due to these inherent model limitations and simplifications, model-
estimated results should be further analyzed, considering such factors 
as the range to specific effects, avoidance, and the likelihood of 
successfully implementing mitigation measures. This analysis uses a 
number of factors in addition to the acoustic model results to predict 
acoustic effects on marine mammals, as described below in the Marine 
Mammal Occurrence and Take Estimation section.
    The underwater radiated noise signature for icebreaking in the 
central Arctic Ocean by CGC HEALY during different types of ice-cover 
was characterized in Roth et al. (2013). The radiated noise signatures 
were characterized for various fractions of ice cover. For modeling, 
the 8/10 and 3/10 ice cover were used. Each modeled day of icebreaking 
consisted of 16 hours of 8/10 ice cover and 8 hours of 3/10 ice cover. 
The sound signature of the 5/10 icebreaking activities, which would 
correspond to half-power icebreaking, was not reported in Roth et al. 
(2013); therefore, the full-power signature was used as a conservative 
proxy for the half-power signature. Icebreaking was modeled for 8 days 
total. Since ice forecasting cannot be predicted more than a few weeks 
in advance, it is unknown if icebreaking would be needed to deploy or 
retrieve the sources after 1 year of transmitting. Therefore, the 
potential for an icebreaking cruise on CGC HEALY was conservatively 
analyzed within the ONR's request for an IHA. As the R/V Sikuliaq is 
not capable of icebreaking, acoustic noise created by icebreaking is 
only modeled for the CGC HEALY. Figures 5a and 5b in Roth et al. (2013) 
depict the source spectrum level versus frequency for 8/10 and 3/10 ice 
cover, respectively. The sound signature of each of the ice coverage 
levels was broken into 1-octave bins (table 7). In the model, each bin 
was included as a separate source on the modeled vessel. When these 
independent sources go active concurrently, they simulate the sound 
signature of CGC HEALY. The modeled source level summed across these 
bins was 196.2 dB for the 8/10 signature and 189.3 dB for the 3/10 ice 
signature. These source levels are a good approximation of the 
icebreaker's observed source level (provided in figure 4b of Roth et 
al. (2013). Each frequency and source level was modeled as an 
independent source, and applied simultaneously to all of the animats 
within NAEMO. Each second was summed across frequency to estimate 
SPLRMS. Any animat exposed to sound levels greater than 120 
dB was considered a take by Level B harassment. For PTS and TTS, 
determinations, sound exposure levels were summed over the duration of 
the

[[Page 66086]]

test and the transit to the deep water deployment area. The method of 
quantitative modeling for icebreaking is considered to be a 
conservative approach; therefore, the number of takes estimated for 
icebreaking are likely an overestimate and would not be expected to 
reach that level.

  Table 7--Modeled Bins for 8/10 Ice Coverage (Full Power) and 3/10 Ice
            Coverage (Quarter Power) Icebreaking on CGC HEALY
------------------------------------------------------------------------
                                                8/10 source  3/10 source
                Frequency (Hz)                   level (dB)   level (dB)
------------------------------------------------------------------------
25............................................          189          187
50............................................          188          182
100...........................................          189          179
200...........................................          190          177
400...........................................          188          175
800...........................................          183          170
1,600.........................................          177          166
3,200.........................................          176          171
6,400.........................................          172          168
12,800........................................          167          164
------------------------------------------------------------------------

Non-Impulsive Acoustic Analysis

    Most likely, individuals affected by acoustic transmission would 
move away from the sound source. Ringed seals may be temporarily 
displaced from their subnivean lairs in the winter, but a pinniped 
would have to be within 5 km (2.7 nm) of a moored source or within 10 
km (5.4 nm) of a drifting source for any behavioral reaction. Any 
effects experienced by individual pinnipeds are anticipated to be 
short-term disturbance of normal behavior, or temporary displacement or 
disruption of animals that may be near elements of the proposed action.
    Of historical sightings registered in the Ocean Biodiversity 
Information System Spatial Ecological Analysis of Megavertebrate 
Populations (OBIS-SEAMAP database) (Halpin et al., 2009) in the ARA 
Study Area, nearly all (99 percent) occurred in summer and fall 
seasons. However, there is no documentation to prove that this is 
because ringed seals would all move out of the Study Area during the 
cold season, or if the lack of sightings is due to the harsh 
environment and ringed seal behavior being prohibitive factors for cold 
season surveying. OBIS-SEAMAP reports 542 animals sighted over 150 
records in the ARA Study Area across all years and seasons. Taking the 
average of 542 animals in 150 records aligns with survey data from 
previous ARA cruises that show up to three ringed seals (or small, 
unidentified pinnipeds assumed to be ringed seals) per day sighted in 
the Study Area. To account for any unsighted animals, that number was 
rounded up to 4. Assuming that four animals would be present in the 
Study Area, a rough estimate of density can be calculated using the 
overall Study Area size:

4 ringed seals / 48,725 km\2\ = 0.00008209 ringed seals/km\2\

    The area of influence surrounding each moored source would be 78.5 
km\2\, and the area of influence surrounding each drifting source would 
be 314 km\2\. The total area of influence on any given day from non-
impulsive acoustic sources would be 942 km\2\. The number of ringed 
seals that could be taken daily can be calculated:

0.00008209 ringed seals/km\2\ x 942 km\2\ = 0.077 ringed seals/day

    To be conservative, the ONR has assumed that one ringed seal would 
be exposed to acoustic transmissions above the threshold for Level B 
harassment, and that each would be exposed each day of the proposed 
action (365 days total). Unlike the NAEMO modeling approach used to 
estimate ringed seal takes in previous ARA IHAs, the occurrence method 
used in this ARA IHA request does not support the differentiation 
between behavioral or TTS exposures. Therefore, all takes are 
classified as Level B harassment and not further distinguished. 
Modeling for all previous years of ARA activities did not result in any 
estimated Level A harassment. NMFS has no reason to expect that the ARA 
activities during the effective dates of this IHA would be more likely 
to result in Level A harassment. Therefore, no Level A harassment is 
anticipated due to the proposed action.

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information which 
will inform the take calculations. We also describe how the marine 
mammal occurrence information is synthesized to produce a quantitative 
estimate of the take that is reasonably likely to occur and proposed 
for authorization.
    The beluga whale density numbers utilized for quantitative acoustic 
modeling are from the Navy Marine Species Density Database (U.S. 
Department of the Navy, 2014). Where available (i.e., June through 15 
October over the continental shelf primarily), density estimates used 
were from Duke density modeling based upon line-transect surveys 
(Ca[ntilde]adas et al., 2020). The remaining seasons and geographic 
area were based on the habitat-based modeling by Kaschner (2004) and 
Kaschner et al. (2006). Density for beluga whales was not distinguished 
by stock and varied throughout the project area geographically and 
monthly; the range of densities in the Study Area is shown in table 8. 
The density estimates for ringed seals are based on the habitat 
suitability modeling by Kaschner (2004) and Kaschner et al. (2006) and 
shown in table 8.

             Table 8--Density Estimates of Impacted Species
------------------------------------------------------------------------
         Common name                 Stock       Density (animals/km\2\)
------------------------------------------------------------------------
Beluga whale.................  Beaufort Sea....       0.000506 to 0.5176
Beluga whale.................  Eastern Chukchi        0.000506 to 0.5176
                                Sea.
Ringed seal..................  Arctic..........         0.1108 to 0.3562
------------------------------------------------------------------------

    Take of all species would occur by Level B harassment only. NAEMO 
was previously used to produce a qualitative estimate of PTS, TTS, and 
behavioral exposures for ringed seals. For this proposed action, a new 
approach that utilizes sighting data from previous surveys conducted 
within the Study Area was used to estimate Level B harassment 
associated with non-impulsive acoustic sources (see section 6.4.3 of 
the IHA application). NAEMO modeling is still used to provide estimated 
takes of beluga whales associated with non-impulsive acoustic sources, 
as well as provide take estimations associated with icebreaking for 
both species. Table 9 shows the total number of requested takes by 
Level B harassment that NMFS proposes to authorize for both beluga 
whale stocks and the Arctic ringed seal stock based upon NAEMO modeled 
results.

[[Page 66087]]

    Density estimates for beluga whales are equal as estimates were not 
distinguished by stock (Kaschner, 2004; Kaschner et al., 2006). The 
ranges of the Beaufort Sea and Eastern Chukchi Sea beluga whales vary 
within the study area throughout the year (Hauser et al., 2014). Based 
upon the limited information available regarding the expected spatial 
distributions of each stock within the study area, take has been 
apportioned equally to each stock (table 9). In addition, in NAEMO, 
animats do not move horizontally or react in any way to avoid sound, 
therefore, the current model may overestimate non-impulsive acoustic 
impacts.

                                                      Table 9--Proposed Take by Level B Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Active        Icebreaking     Icebreaking   Total proposed                   Percentage of
              Species                       Stock            acoustics     (behavioral)        (TTS)           take        SAR abundance    population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga whale......................  Beaufort Sea........         \a\ 177          \a\ 21               0              99          39,258              <1
Beluga whale......................  Chukchi Sea.........         \a\ 177          \a\ 21               0              99          13,305              <1
Ringed seal.......................  Arctic..............             365             538               1             904   \b\ UND (171,              <1
                                                                                                                                    418)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Acoustic and icebreaking exposures to beluga whales were not modeled at the stock level as the density value is not distinguished by stock in the
  Arctic for beluga whales (U.S. Department of the Navy, 2014). Estimated take of beluga whales due to active acoustics is 177 and 21 due to icebreaking
  activities, totaling 198 takes of beluga whales. The total take was evenly distributed among the two stocks.
\b\ A reliable population estimate for the entire Arctic stock of ringed seals is not available and NMFS SAR lists it as Undetermined (UND). Using a sub-
  sample of data collected from the U.S. portion of the Bering Sea (Conn et al., 2014), an abundance estimate of 171,418 ringed seals has been
  calculated but this estimate does not account for availability bias due to seals in the water or in the shore-fast ice zone at the time of the survey.
  The actual number of ringed seals in the U.S. portion of the Bering Sea is likely much higher. Using the minimum population size (Nmin = 158,507)
  based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a negatively biased estimate.

Proposed Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to the 
activity, and other means of effecting the least practicable impact on 
the species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of the species or stock for taking for certain 
subsistence uses. NMFS regulations require applicants for incidental 
take authorizations to include information about the availability and 
feasibility (economic and technological) of equipment, methods, and 
manner of conducting the activity or other means of effecting the least 
practicable adverse impact upon the affected species or stocks, and 
their habitat (50 CFR 216.104(a)(11)). The 2004 NDAA amended the MMPA 
as it relates to military readiness activities and the incidental take 
authorization process such that ``least practicable impact'' shall 
include consideration of personnel safety, practicality of 
implementation, and impact on the effectiveness of the military 
readiness activity.
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat, as 
well as subsistence uses. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the likelihood that the measure will be effective if 
implemented (probability of accomplishing the mitigating result if 
implemented as planned), the likelihood of effective implementation 
(probability implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The following measures are proposed for this IHA:
     All vessels operated by or for the Navy must have 
personnel assigned to stand watch at all times while underway. Watch 
personnel must employ visual search techniques using binoculars. While 
underway and while using active acoustic sources/towed in-water 
devices, at least one person with access to binoculars is required to 
be on watch at all times.
     Vessel captains and vessel personnel must remain alert at 
all times, proceed with extreme caution, and operate at a safe speed so 
that the vessel can take proper and effective action to avoid any 
collisions with marine mammals.
     During moored and drifting acoustic source deployment and 
recovery, ONR must implement a mitigation zone of 55 m (180 ft) around 
the deployed source. Deployment and recovery must cease if a marine 
mammal is visually deterred within the mitigation zone. Deployment and 
recovery may recommence if any one of the following conditions are met:
    [cir] The animal is observed exiting the mitigation zone;
    [cir] The animal is thought to have exited the mitigation zone 
based on a determination of its course, speed, and movement relative to 
the sound source;
    [cir] The mitigation zone has been clear from any additional 
sightings for a period of 15 minutes for pinnipeds and 30 minutes for 
cetaceans.
     Vessels must avoid approaching marine mammals head-on and 
must maneuver to maintain a mitigation zone of 457 m (500 yards) around 
all observed cetaceans and 183 m (200 yards) around all other observed 
marine mammals, provided it is safe to do so.
     Activities must cease if a marine mammal species for which 
take was not authorized, or a species for which authorization was 
granted but the authorized number of takes have been met, is observed 
approaching or within the mitigation zone (table 10). Activities must 
not resume until the animal is confirmed to have left the area.
     Vessel captains must maintain at-sea communication with 
subsistence hunters to avoid conflict of vessel transit with hunting 
activity.

                   Table 10--Proposed Mitigation Zones
------------------------------------------------------------------------
   Activity and/or effort type          Species         Mitigation zone
------------------------------------------------------------------------
Acoustic source deployment and    Beluga whale......  55 m (180 ft).
 recovery, stationary.

[[Page 66088]]

 
Acoustic source deployment and    Ringed seal.......  55 m (180 ft).
 recovery, stationary.
Transit.........................  Beluga whale......  457 m (500 yards).
Transit.........................  Ringed seal.......  183 m (200 yards).
------------------------------------------------------------------------

    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, areas of similar significance, 
and on the availability of such species or stock for subsistence uses.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present while 
conducting the activities. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
     Mitigation and monitoring effectiveness.
    The Navy has coordinated with NMFS to develop an overarching 
program plan in which specific monitoring would occur. This plan is 
called the Integrated Comprehensive Monitoring Program (ICMP) (U.S. 
Department of the Navy, 2011). The ICMP has been developed in direct 
response to Navy permitting requirements established through various 
environmental compliance efforts. As a framework document, the ICMP 
applies by regulation to those activities on ranges and operating areas 
for which the Navy is seeking or has sought incidental take 
authorizations. The ICMP is intended to coordinate monitoring efforts 
across all regions and to allocate the most appropriate level and type 
of effort based on a set of standardized research goals, and in 
acknowledgement of regional scientific value and resource availability.
    The ICMP is focused on Navy training and testing ranges where the 
majority of Navy activities occur regularly as those areas have the 
greatest potential for being impacted. ONR's ARA in comparison is a 
less intensive test with little human activity present in the Arctic. 
Human presence is limited to the deployment of sources that would take 
place over several weeks. Additionally, due to the location and nature 
of the testing, vessels and personnel would not be within the study 
area for an extended period of time. As such, more extensive monitoring 
requirements beyond the basic information being collected would not be 
feasible as it would require additional personnel and equipment to 
locate seals and a presence in the Arctic during a period of time other 
then what is planned for source deployment. However, ONR will record 
all observations of marine mammals, including the marine mammal's 
species identification, location (latitude/longitude), behavior, and 
distance from project activities. ONR will also record date and time of 
sighting. This information is valuable in an area with few recorded 
observations.
    Marine mammal monitoring must be conducted in accordance with the 
Navy's ICMP and the proposed IHA:
     While underway, all vessels must have at least one person 
trained through the U.S. Navy Marine Species Awareness Training Program 
on watch during all activities;
     Watch personnel must use standardized data collection 
forms, whether hard copy or electronic. Watch personnel must 
distinguish between sightings that occur during transit or during 
deployment or recovery of acoustic sources. Data must be recorded on 
all days of activities, even if marine mammals are not sighted;
     At minimum, the following information must be recorded:
    [cir] Vessel name;
    [cir] Watch personnel names and affiliation;
    [cir] Effort type (i.e., transit, deployment, recovery); and
    [cir] Environmental conditions (at the beginning of watch stander 
shift and whenever conditions change significantly), including Beaufort 
Sea State (BSS) and any other relevant weather conditions, including 
cloud cover, fog, sun glare, and overall visibility to the horizon.
     Upon visual observation of any marine mammal, the 
following information must be recorded:
    [cir] Date/time of sighting;
    [cir] Identification of animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified) and the composition of the 
group if there is a mix of species;
    [cir] Location (latitude/longitude) of sighting;
    [cir] Estimated number of animals (high/low/best);
    [cir] Description (as many distinguishing features as possible of 
each individual seen, including length, shape, color, pattern, scars or 
markings, shape and size of dorsal fin, shape of head, and blow 
characteristics);
    [cir] Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping,

[[Page 66089]]

diving, feeding, traveling; as explicit and detailed as possible; 
length of time observed in the mitigation zone, note any observed 
changes in behavior);
    [cir] Distance from vessel to animal;
    [cir] Direction of animal's travel relative to the vessel;
    [cir] Platform activity at time of sighting (i.e., transit, 
deployment, recovery); and
    [cir] Weather conditions (i.e., BSS, cloud cover).
    [cir] During icebreaking, the following information must be 
recorded:
    [cir] Start and end time of icebreaking; and
    [cir] Ice cover conditions.
     During deployment and recovery of acoustic sources or 
UUVs, visual observation must begin 30 minutes prior to deployment or 
recovery and continue through 30 minutes following the source 
deployment or recovery.
     The ONR must submit its draft report(s) on all monitoring 
conducted under the IHA within 90 calendar days of the completion of 
monitoring or 60 calendar days prior to the requested issuance of any 
subsequent IHA for research activities at the same location, whichever 
comes first. A final report must be prepared and submitted within 30 
calendar days following receipt of any NMFS comments on the draft 
report. If no comments are received from NMFS within 30 calendar days 
of receipt of the draft report, the report shall be considered final.
     All draft and final monitoring reports must be submitted 
to [email protected] and [email protected].
     The marine mammal report, at minimum, must include:
    [cir] Dates and times (begin and end) of all marine mammal 
monitoring;
    [cir] Acoustic source use or icebreaking;
    [cir] Watch stander location(s) during marine mammal monitoring;
    [cir] Environmental conditions during monitoring periods (at 
beginning and end of watch standing shift and whenever conditions 
change significantly), including BSS and any other relevant weather 
conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
    [cir] Upon observation of a marine mammal, the following 
information:
    [ssquf] Name of watch stander who sighted the animal(s), the watch 
stander location, and activity at time of sighting;
    [ssquf] Time of sighting;
    [ssquf] Identification of the animal(s) (e.g., genus/species, 
lowest possible taxonomic level, or unidentified), watch stander 
confidence in identification, and the composition of the group if there 
is a mix of species;
    [ssquf] Distance and location of each observed marine mammal 
relative to the acoustic source or icebreaking for each sighting;
    [ssquf] Estimated number of animals (min/max/best estimate);
    [ssquf] Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
    [ssquf] Animal's closest point of approach and estimated time spent 
within the harassment zone; and
    [ssquf] Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses thought to have resulted from the 
activity (e.g., no response or changes in behavioral state such as 
ceasing feeding, changing direction, flushing, or breaching.
    [cir] Number of shutdowns during monitoring, if any;
    [cir] Marine mammal sightings (including the marine mammal's 
location (latitude/longitude));
    [cir] Number of individuals of each species observed during source 
deployment, operation, and recovery; and
    [cir] Detailed information about implementation of any mitigation 
(e.g., shutdowns, delays), a description of specific actions that 
ensued, and resulting changes in behavior of the animal(s), if any.
     The ONR must submit all watch stander data electronically 
in a format that can be queried, such as a spreadsheet or database 
(i.e., digital images of data sheets are not sufficient).
     Reporting injured or dead marine mammals:
    [cir] In the event that personnel involved in the specified 
activities discover an injured or dead marine mammal, the ONR must 
report the incident to the Office of Protected Resources (OPR), NMFS 
([email protected] and [email protected]) and to 
the Alaska regional stranding network (877-925-7773) as soon as 
feasible. If the death or injury was clearly caused by the specified 
activity, the ONR must immediately cease the activities until NMFS OPR 
is able to review the circumstances of the incident and determine what, 
if any, additional measures are appropriate to ensure compliance with 
the terms of this IHA. The ONR must not resume their activities until 
notified by NMFS.
    [cir] The report must include the following information:
    [ssquf] Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    [ssquf] Species identification (if known) or description of the 
animal(s) involved;
    [ssquf] Condition of the animal(s) (including carcass condition if 
the animal is dead);
    [ssquf] Observed behaviors of the animal(s), if alive;
    [ssquf] If available, photographs or video footage of the 
animal(s); and
    [ssquf] General circumstances under which the animal was 
discovered.
     Vessel Strike: In the event of a vessel strike of a marine 
mammal by any vessel involved in the activities covered by the 
authorization, the ONR shall report the incident to OPR, NMFS and to 
the Alaska regional stranding coordinator (877-925-7773) as soon as 
feasible. The report must include the following information:
    [cir] Time, date, and location (latitude/longitude) of the 
incident;
    [cir] Species identification (if known) or description of the 
animal(s) involved;
    [cir] Vessel's speed during and leading up to the incident;
    [cir] Vessel's course/heading and what operations were being 
conducted (if applicable);
    [cir] Status of all sound sources in use;
    [cir] Description of avoidance measures/requirements that were in 
place at the time of the strike and what additional measures were 
taken, if any, to avoid strike;
    [cir] Environmental conditions (e.g., wind speed and direction, 
BSS, cloud cover, visibility) immediately preceding the strike;
    [cir] Estimated size and length of animal that was struck;
    [cir] Description of the behavior of the marine mammal immediately 
preceding and following the strike;
    [cir] If available, description of the presence and behavior of any 
other marine mammals immediately preceding the strike;
    [cir] Estimated fate of the animal (e.g., dead, injured but alive, 
injured and moving, blood or tissue observed in the water, status 
unknown, disappeared); and
    [cir] To the extent practicable, photographs or video footage of 
the animal(s).

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of

[[Page 66090]]

recruitment or survival (i.e., population-level effects). An estimate 
of the number of takes alone is not enough information on which to base 
an impact determination. In addition to considering estimates of the 
number of marine mammals that might be ``taken'' through harassment, 
NMFS considers other factors, such as the likely nature of any impacts 
or responses (e.g., intensity, duration), the context of any impacts or 
responses (e.g., critical reproductive time or location, foraging 
impacts affecting energetics), as well as effects on habitat, and the 
likely effectiveness of the mitigation. We also assess the number, 
intensity, and context of estimated takes by evaluating this 
information relative to population status. Consistent with the 1989 
preamble for NMFS' implementing regulations (54 FR 40338, September 29, 
1989), the impacts from other past and ongoing anthropogenic activities 
are incorporated into this analysis via their impacts on the baseline 
(e.g., as reflected in the regulatory status of the species, population 
size and growth rate where known, ongoing sources of human-caused 
mortality, or ambient noise levels).
    To avoid repetition, the discussion of our analysis applies to 
beluga whales and ringed seals, given that the anticipated effects of 
this activity on these different marine mammal stocks are expected to 
be similar. Where there are meaningful differences between species or 
stocks, or groups of species, in anticipated individual responses to 
activities, impact of expected take on the population due to 
differences in population status, or impacts on habitat, they are 
described independently in the analysis below.
    Underwater acoustic transmissions associated with the proposed ARA, 
as outlined previously, have the potential to result in Level B 
harassment of beluga seals and ringed seals in the form of behavioral 
disturbances. No serious injury, mortality, or Level A harassment are 
anticipated to result from these described activities. Effects on 
individual belugas or ringed seals taken by Level B harassment could 
include alteration of dive behavior and/or foraging behavior, effects 
to breathing rates, interference with or alteration of vocalization, 
avoidance, and flight. More severe behavioral responses are not 
anticipated due to the localized, intermittent use of active acoustic 
sources. Exposure duration is likely to be short-term and individuals 
will, most likely, simply be temporarily displaced by moving away from 
the acoustic source. Exposures are, therefore, unlikely to result in 
any significant realized decrease in fitness for affected individuals 
or adverse impacts to stocks as a whole.
    Arctic ringed seals are listed as threatened under the ESA. The 
primary concern for Arctic ringed seals is the ongoing and anticipated 
loss of sea ice and snow cover resulting from climate change, which is 
expected to pose a significant threat to ringed seals in the future 
(Muto et al., 2021). In addition, Arctic ringed seals have also been 
experiencing a UME since 2019 although the cause of the UME is 
currently undetermined. As mentioned earlier, no mortality or serious 
injury to ringed seals is anticipated nor proposed to be authorized. 
Due to the short-term duration of expected exposures and required 
mitigation measures to reduce adverse impacts, we do not expect the 
proposed ARA to compound or exacerbate the impacts of the ongoing UME.
    A small portion of the Study Area overlaps with ringed seal 
critical habitat. Although this habitat contains features necessary for 
ringed seal formation and maintenance of subnivean birth lairs, basking 
and molting, and foraging, these features are also available throughout 
the rest of the designated critical habitat area. Any potential limited 
displacement of ringed seals from the proposed ARA study area would not 
be expected to interfere with their ability to access necessary habitat 
features, given the availability of similar necessary habitat features 
nearby.
    The Study Area also overlaps with beluga whale migratory and 
feeding BIAs. Due to the small amount of overlap between the BIAs and 
the proposed ARA study area as well as the low intensity and short-term 
duration of acoustic sources and required mitigation measures, we 
expect minimal impacts to migrating or feeding belugas. Shutdown zones 
are expected to avoid the potential for Level A harassment of belugas 
and ringed seals, and to minimize the severity of any Level B 
harassment. The requirements of trained dedicated watch personnel and 
speed restrictions will also reduce the likelihood of any ship strikes 
to migrating belugas.
    In all, the proposed activities are expected to have minimal 
adverse effects on marine mammal habitat. While the activities may 
cause some fish to leave the area of disturbance, temporarily impacting 
marine mammals' foraging opportunities, this would encompass a 
relatively small area of habitat leaving large areas of existing fish 
and marine mammal foraging habitat unaffected. As such, the impacts to 
marine mammal habitat are not expected to impact the health or fitness 
of any marine mammals.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect any of the species 
or stocks through effects on annual rates of recruitment or survival:
     No serious injury or mortality is anticipated or 
authorized;
     Impacts would be limited to Level B harassment only;
     Only temporary and relatively low-level behavioral 
disturbances are expected to result from these proposed activities; and
     Impacts to marine mammal prey or habitat will be minimal 
and short term.
    The anticipated and authorized take is not expected to impact the 
reproduction or survival of any individual marine mammals, much less 
rates of recruitment or survival. Based on the analysis contained 
herein of the likely effects of the specified activity on marine 
mammals and their habitat, and taking into consideration the 
implementation of the proposed monitoring and mitigation measures, NMFS 
preliminarily finds that the total marine mammal take from the proposed 
activity will have a negligible impact on all affected marine mammal 
species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    Subsistence hunting is important for many Alaska Native 
communities. A study of the North Slope villages of Nuiqsut, Kaktovik, 
and Utqia[gdot]vik identified the primary resources used for 
subsistence and the locations for harvest (Stephen R. Braund & 
Associates, 2010), including terrestrial mammals, birds, fish, and 
marine mammals (bowhead whale, ringed seal,

[[Page 66091]]

bearded seal, and walrus). Ringed seals and beluga whales are likely 
located within the project area during this proposed action, yet the 
proposed action would not remove individuals from the population nor 
behaviorally disturb them in a manner that would affect their behavior 
more than 100 km farther inshore where subsistence hunting occurs. The 
permitted sources would be placed far outside of the range for 
subsistence hunting. The closest active acoustic source (fixed or 
drifting) within the proposed project site that is likely to cause 
Level B harassment is approximately 204 km (110 nm) from land. This 
ensures a significant standoff distance from any subsistence hunting 
area. The closest distance to subsistence hunting (130 km (70 nm)) is 
well beyond the largest distance from the sound sources in use at which 
behavioral harassment would be expected to occur (20 km (10.8 nm)) 
described above. Furthermore, there is no reason to believe that any 
behavioral disturbance of beluga whales or ringed seals that occurs far 
offshore (we do not anticipate any Level A harassment) would affect 
their subsequent behavior in a manner that would interfere with 
subsistence uses should those animals later interact with hunters.
    In addition, ONR has been communicating with the Native communities 
about the proposed action. The ONR-sponsored chief scientist for AMOS 
gave a briefing on ONR research planned for 2024-2025 Alaska Eskimo 
Whaling Commission (AEWC) meeting on December 15, 2023 in Anchorage, 
Alaska. No questions were asked from the commissioners during the brief 
or in subsequent weeks afterwards. The AEWC consists of representatives 
from 11 whaling villages (Wainwright, Utqia[gdot]vik, Savoonga, Point 
Lay, Nuiqut, Kivalina, Kaktovik, Wales, Point Hope, Little Diomede, and 
Gambell). These briefings have communicated the lack of any effect on 
subsistence hunting due to the distance of the sources from hunting 
areas. ONR-supported scientists also attend Arctic Waterways Safety 
Committee (AWSC) and AEWC meetings on a regular basis to discuss past, 
present, and future research activities. While no take is anticipated 
to result during transit, points of contact for at-sea communication 
will also be established between vessel captains and subsistence 
hunters to avoid any conflict of ship transit with hunting activity.
    Based on the description of the specified activity, distance of the 
study area from subsistence hunting grounds, the measures described to 
minimize adverse effects on the availability of marine mammals for 
subsistence purposes, and the proposed mitigation and monitoring 
measures, NMFS has preliminarily determined that there will not be an 
unmitigable adverse impact on subsistence uses from ONR's proposed 
activities.

Peer Review of the Monitoring Plan

    The MMPA requires that monitoring plans be independently peer 
reviewed where the proposed activity may affect the availability of a 
species or stock for taking for subsistence uses (16 U.S.C. 
1371(a)(5)(D)(ii)(III)). Given the factors discussed above, NMFS has 
also determined that the activity is not likely to affect the 
availability of any marine mammal species or stock for taking for 
subsistence uses, and therefore, peer review of the monitoring plan is 
not warranted for this project.

Endangered Species Act

    Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.) 
requires that each Federal agency insure that any action it authorizes, 
funds, or carries out is not likely to jeopardize the continued 
existence of any endangered or threatened species or result in the 
destruction or adverse modification of designated critical habitat. To 
ensure ESA compliance for the issuance of IHAs, NMFS consults 
internally whenever we propose to authorize take for endangered or 
threatened species, in this case with the Alaska Regional Office (AKR).
    NMFS is proposing to authorize take of ringed seals, which are 
listed under the ESA. The Permits and Conservation Division has 
requested initiation of section 7 consultation with the AKR for the 
issuance of this IHA. NMFS will conclude the ESA consultation prior to 
reaching a determination regarding the proposed issuance of the 
authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the ONR for conducting a seventh year of ARA in the 
Beaufort and Chukchi Seas from September 2024 to September 2025, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. A draft of the proposed IHA can be found 
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed ARA. 
We also request comment on the potential renewal of this proposed IHA 
as described in the paragraph below. Please include with your comments 
any supporting data or literature citations to help inform decisions on 
the request for this IHA or a subsequent renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, 1-year renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical activities as described in the Description of Proposed 
Activity section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activity section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed renewal IHA effective date (recognizing that the 
renewal IHA expiration date cannot extend beyond 1 year from expiration 
of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take).
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: August 8, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2024-18130 Filed 8-13-24; 8:45 am]
BILLING CODE 3510-22-P