[Federal Register Volume 87, Number 142 (Tuesday, July 26, 2022)]
[Notices]
[Pages 44339-44364]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-15937]


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

DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XC070]


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 5)

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.

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

SUMMARY: NMFS has received a request from 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

[[Page 44340]]

activities. NMFS is also requesting comments on a possible one-time, 
one-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 August 
25, 2022.

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].
    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 
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: Jessica Taylor, Office of Protected 
Resources, NMFS, (301) 427-8401. 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 above.

SUPPLEMENTARY INFORMATION:

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 mitigation, 
monitoring and reporting of the takings are set forth.
    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 addressed here qualifies as a military 
readiness activity. The definitions of all applicable MMPA statutory 
terms cited above are included in the relevant sections below.

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; referred to as an EA in this document) 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 U.S. Navy prepared a supplemental EA. Prior to issuing 
the IHA in 2019, NMFS reviewed the supplemental EA 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 U.S. 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 
supplement EA and FONSI from 2019 when issuing the renewal IHA in 2020 
(85 FR 41560; July 10, 2020).
    In 2021, the U.S. Navy submitted a request for an IHA for 
incidental take of marine mammals during continuation of ARA. NMFS 
reviewed the U.S. Navy's EA 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 EA and signed a Finding of No Significant 
Impact (FONSI) (86 FR 54931, October 5, 2021).
    Accordingly, NMFS preliminarily has determined to adopt the U.S. 
Navy's OEA for Office of Naval Research Arctic Research Activities 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 21, 2022, NMFS received a request from ONR for an IHA to 
take marine mammals incidental to ARA in the Beaufort and eastern 
Chukchi Seas. The application was deemed adequate and complete on June 
30, 2022. ONR's request is for take of beluga whales (Delphinapterus 
leucas; two stocks) and ringed seals (Pusa hispida hispida) by Level B 
harassment. Neither ONR nor NMFS expect serious injury or mortality

[[Page 44341]]

to result from this activity and, therefore, an IHA is appropriate.
    This proposed IHA would cover the fifth year of a larger project 
for which ONR obtained prior 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) and may request take authorization for 
subsequent facets of the overall project. This IHA would be valid for a 
period of one year from the date of issuance (mid-September 2022 to 
mid- September 2023). The larger project supports the development of an 
under-ice navigation system under the ONR Arctic Mobile Observing 
System (AMOS) project. ONR has complied with all the requirements 
(e.g., mitigation, monitoring, and reporting) of the previous 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).

Description of Proposed Activity

Overview

    ONR's ARA include scientific experiments to be conducted in support 
of the programs named above. Specifically, the project includes the 
Arctic Mobile Observing System (AMOS) experiments in the Beaufort and 
Chukchi Seas. Project activities involve acoustic testing and a multi-
frequency navigation system concept test using left-behind active 
acoustic sources. More specifically, these experiments involve the 
deployment of moored, drifting, and ice-tethered active acoustic 
sources from the Research Vessel (R/V) Sikuliaq. Another vessel will be 
used to retrieve the acoustic sources. Underwater sound from the 
acoustic sources may result in Level B harassment of marine mammals.

Dates and Duration

    This proposed action would occur from mid-September 2022 through 
mid-September 2023. The 2022 cruise would leave from Nome, Alaska on 
September 14, 2022 using the R/V Sikuliaq and involve 120 hours of 
active source testing. During this first cruise, several acoustic 
sources would be deployed from the ship. Some acoustic sources will be 
left behind to provide year-round observation of the Arctic 
environment. Gliders deployed during the September 2022 cruise may be 
recovered before the research vessel departs the study area or during a 
September 2023 cruise. Up to seven fixed acoustic navigation sources 
transmitting at 900 Hertz (Hz) would remain in place for a year. 
Drifting and moored oceanographic sensors would record environmental 
parameters throughout the year. Autonomous weather stations and ice 
mass balance buoys would also be deployed to record environmental 
measurements throughout the year (Table 1). The research vessel is 
planned to return to Nome, Alaska on October 28, 2022. ONR will apply 
for a renewal or separate IHA, as appropriate, for activities conducted 
during the planned September 2023 cruise.
    During the scope of this proposed project, other activities may 
occur at different intervals that would assist ONR in meeting the 
scientific objectives of the various projects discussed above. However, 
these activities are designated as de minimis sources in ONR's 2022-
2023 IHA application (consistent with analyses presented in support of 
previous Navy ONR IHAs), or would not produce sounds detectable by 
marine mammals (see discussion on de minimis sources below). These 
include the deployment of a Woods Hole Oceanographic Institution (WHOI) 
micromodem, acoustic Doppler current profilers (ADCP), and ice 
profilers (Table 2).

Geographic Region

    This proposed action would occur across the U.S. Exclusive Economic 
Zone (EEZ) in both 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 110 nm (204 km). The proposed 
study area is approximately 639,267 km\2\.
BILLING CODE 3510-22-P

[[Page 44342]]

[GRAPHIC] [TIFF OMITTED] TN26JY22.156

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    The ONR Arctic and Global Prediction Program supports two major 
projects: Stratified Ocean Dynamics of the Arctic (SODA) and 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 AMOS project constitutes the development of a new system 
involving very low (35 Hz)), low (900 Hz), and mid-frequency 
transmissions (10 kilohertz (kHz)). The AMOS project would utilize 
acoustic sources and receivers to provide a means of performing under-
ice navigation for

[[Page 44343]]

gliders and unmanned underwater 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 effects of this changing 
environment for military readiness, as well as the implications of 
environmental change to humans and animals. Very-low frequency 
technology is important in extending the range of navigation systems. 
The technology also 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.
    Active acoustic sources would be lowered from the cruise vessel 
while stationary, deployed on gliders and UUVs, or deployed on fixed 
AMOS moorings. This project would use groups of drifting buoys with 
sources and receivers communicating oceanographic information to a 
satellite in near real time. These sources would employ low-frequency 
transmissions only (900 Hz).
    The proposed action would utilize non-impulsive acoustic sources, 
although not all sources will cause take of marine mammals. Any marine 
mammal takes would only arise from the operation of non-impulsive 
active sources. Although not currently planned, ice breaking 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, ice breaking could result 
in potential Level B harassment takes.
    Below are descriptions of the equipment and platforms that would be 
deployed at different times during the proposed action.

Research Vessels

    The R/V Sikuliaq would perform the research cruise in September 
2022 and conduct testing of acoustic sources during the cruise, as well 
as leave sources behind to operate as a year-round navigation system 
observation. R/V Sikuliaq has a maximum speed of approximately 12 knots 
(6.2 m/s) with a cruising speed of 11 knots (5.7 m/s) (University of 
Alaska Fairbanks 2014). The R/V Sikuliaq is not an ice breaking 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.
    The ship to be used in September 2023 to retrieve any acoustic 
sources could potentially be the CGC Healy. CGC Healy travels at a 
maximum speed of 17 knots (8.7 m/s) with a cruising speed of 12 knots 
(6.2 m/s) (United States Coast Guard 2013), and a maximum speed of 3 
knots (1.5 m/s) when traveling through 4.5 feet (1.07 m) of sea ice 
(United States Coast Guard 2013). 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.

Moored and Drifting Acoustic Sources

    During the September 2022 cruise, active acoustic sources would be 
lowered from the cruise vessel while stationary, deployed on gliders 
and UUVs, or deployed on fixed AMOS moorings. This would be done for 
intermittent testing of the system components. The total amount of 
active source testing for ship-deployed sources used during the cruise 
would be 120 hours. The testing would take place near the seven source 
locations on Figure 1, with UUVs running tracks within the designated 
box. During this testing, 35 Hz, 900 Hz, and 10 kHz acoustic signals, 
as well as acoustic modems would be employed.
    Up to seven fixed acoustic navigation sources transmitting at 900 
Hz would remain in place for a year and continue transmitting during 
this time. 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 very low frequency (VLF) sources 
transmitting at 35 Hz would be deployed in a similar manner. Two Ice 
Gateway Buoys (IGB) would also be configured with active acoustic 
sources. 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. For the purposes of this 
proposed action, activities potentially resulting in take would not be 
included in the fall 2023 cruise; a subsequent application would be 
provided by ONR depending on the scientific plan associated with that 
cruise.

                                    Table 1--Characteristics for the Modeled Acoustic Sources for the Proposed Action
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                           Signal strength  (dB
             Platform                  Acoustic source        Purpose/function           Frequency            re1uPa @1m) \1\           Band width
--------------------------------------------------------------------------------------------------------------------------------------------------------
REMUS 600 UUV (1).................  WHOI \2\/Micro-modem.  Acoustic               900-950 Hz \3\.........  NTE \3\ 180 dB by     50 Hz.
                                                            communication.                                  sys design limits.
                                    UUV/WHOI Micro-modem.  Acoustic               8-14 kHz \3\...........  NTE 185 dB by sys     5 kHz.
                                                            communication.                                  design limits.
IGB \3\ (drifting) (2)............  WHOI Micro-modem.....  Acoustic               900-950 Hz.............  NTE 180 dB by sys     50 Hz.
                                                            communication.                                  design limits.
                                    WHOI Micro-modem.....  Acoustic               8-14 kHz...............  NTE 185 dB by sys     5 kHz.
                                                            communication.                                  design limits.
Mooring (9).......................  WHOI Micro-modem (7).  Acoustic navigation..  900-950 Hz.............  NTE 180 dB by sys     50 Hz.
                                                                                                            design limits.

[[Page 44344]]

 
                                    VLF \3\ (2)..........  Acoustic navigation..  35 Hz..................  NTE 190 dB..........  6 Hz.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ dB re 1 [mu]Pa at 1 m = decibels referenced to 1 micropascal at 1 meter.
\2\ WHOI = Woods Hole Oceanographic Institution.
\3\ Hz = Hertz; IGB = Ice Gateway Buoy; kHz = 1 kilohertz; NTE = not to exceed; VLF = very low frequency

Activities Not Likely To Result in Take

    The following in-water 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 document.
    De minimis Sources--The Navy characterizes de minimis sources as 
those with the following parameters: Low source levels, narrow beams, 
downward directed transmission, short pulse lengths, frequencies 
outside known marine mammal hearing ranges, or some combination of 
these factors (Department of the Navy, 2013b). NMFS concurs with the 
Navy'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, ADCPs, ice profilers, and additional sources below 160 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. Descriptions of some 
de minimis sources are discussed below and in Table 2. More detailed 
descriptions of these de minimis sources can be found in ONR's IHA 
application under Section 1.1.1.2.

                         Table 2--Parameters for De Minimis Non-Impulsive Active Sources
----------------------------------------------------------------------------------------------------------------
                                                 Sound pressure
                                Frequency range   level  (dB re   Pulse length     Duty cycle       De minimis
         Source name                 (kHz)        1 [mu]Pa at 1        (s)          (percent)     justification
                                                       m)
----------------------------------------------------------------------------------------------------------------
ADCP.........................  >200, 150, or 75             190          <0.001            <0.1  Very low pulse
                                                                                                  length, narrow
                                                                                                  beam, moderate
                                                                                                  source level.
Nortek Signature 500 kHz       500.............             214            <0.1             <13  Very high
 Doppler Velocity Log.                                                                            frequency.
CTD \1\ Attached Echosounder.  5-20............             160           0.004               2  Very low source
                                                                                                  level.
----------------------------------------------------------------------------------------------------------------
\1\ 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 in the top 20 ft (6 m) of the 
water column. Integrated Autonomous Drifters would have a long 
temperate string extending down to 656 ft (200 m) 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 820 ft 
(250 m) depth.
    Up to 20 Argo-type autonomous profiling floats may be deployed in 
the central Beaufort Sea. Argo floats drift at 4,921 ft (1,500 m) 
depth, profiling from 6,562 ft (2,000 m) to the sea surface once every 
10 days to collect profiles of 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 1,640 ft (500 m) 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 with a sound source that is de minimis due to its very high 
frequency (200 kHz). The Ice Mass Balance Buoy is a 20 ft (6 m) sensor 
string, which is deployed through a 2 inch (5 cm) hole drilled into the 
ice. The string is weighted by a 2.2 lb (1 kg) 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,

[[Page 44345]]

and will drift with the ice, making measurements. The instruments are 
destroyed as their host ice floes melt (likely in summer, roughly one 
year after deployment). After the instruments are deployed 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, incorporated here by reference, instead of 
reprinting the information. Additional information regarding population 
trends and threats may be found in NMFS' Stock Assessment Reports 
(SARs; 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 action, 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 
authorized here, PBR and annual serious injury and mortality from 
anthropogenic sources are included here as gross indicators of the 
status of the species 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. 2020 SARs (e.g., Muto et al. 2021), with the exception of 
Beaufort Sea beluga whales. The 2020 SAR for the Beaufort Sea stock of 
beluga whales has temporarily been withdrawn for further review, 
therefore, the NMFS' U.S. 2021 draft SAR represents the most recent 
stock assessment for this stock. All values presented in Table 3 are 
the most recent available at the time of publication (including from 
the draft 2021 SARs) online at: www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                              Table 3--Species Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Monodontidae:
    Beluga Whale....................  Delphinapterus leucas..  Beaufort Sea...........  -, -, N             39,258 (0.229, N/A,       \4\ UND        104
                                                                                                             1992).
    Beluga Whale....................  Delphinapterus leucas..  Eastern Chukchi Sea....  -, -, N             13,305 (0.51, 8,875,          178         55
                                                                                                             2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Ringed Seal \5\.................  Pusa hispida hispida...  Arctic.................  T, D, Y             171,418 (N/A, 158,507,      5,100      6,459
                                                                                                             171,418.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (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.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is the coefficient of variation; Nmin is the minimum estimate
  of stock abundance. In some cases, CV is not applicable [explain if this is the case].
\3\ 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, ship 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.
\4\ The 2016 guidelines for preparing SARs state that abundance estimates older than 8 years should not be used to calculate PBR due to a decline in the
  reliability of an aged estimate. Therefore, the PBR for this stock is considered undetermined.
\5\ Abundance and associated values for ringed seals are for the U.S. population in the Bering Sea only.

    As indicated above, the two 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), ribbon seals 
(Histiophoca fasciata), have been documented in the area, the temporal 
and/or spatial occurrence of these 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, spotted seal, bearded 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 (Carretta et al., 2018; Muto et al., 2018). 
Similarly, spotted seals tend to prefer pack ice areas with water 
depths less than 200 m during the spring and move to coastal habitats 
in the summer and fall, found as far north

[[Page 44346]]

as 69-72[deg] N (Muto et al., 2018). Although the study area includes 
some waters south of 72[deg] 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., 2018). 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, narwhal, and 
ribbon seal, these species will not be discussed further in this 
proposed notice.
    The Navy has 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., 2021b). 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 shorefast ice zone (Muto 
et al., 2021b). Muto et al., (2021b) 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, in the interest in making conservative decisions, 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 (USFWS) and 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 are both migratory and 
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 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.
    A migratory Biologically Important Area (BIA) for belugas in the 
Eastern Chukchi and Alaskan Beaufort Sea overlaps the southern and 
western portion of the proposed project site. One migration corridor is 
in use from April to May. The second corridor, located in the Alaskan 
Beaufort Sea, is used by migrating belugas from September to October 
(Calambokidis et al., 2015). 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., 2017). 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 593 nm (1,100 km) 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[deg] 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[deg] 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 Seals

    Ringed seals are the most common pinniped in the proposed project 
site 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, 1988c). Ringed seals can be found 
further offshore than other pinnipeds since they can maintain breathing 
holes in ice thickness greater than 6.6 ft (2 m) (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 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 land-fast ice as well as stable 
pack ice. Lentfer (1972) found that ringed seals north of 
Utqia[gdot]vik, Alaska (formally known as Barrow, 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

[[Page 44347]]

seas (Frost, 1985; Kelly, 1988c). Passive acoustic monitoring of ringed 
seals from a high frequency recording package deployed at a depth of 
787 ft (240 m) in the Chukchi Sea 65 nautical miles (120 km) 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., 
(2010b) 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 is 0.62 km\2\ for adult males and 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., 2010b). 
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., 2010b). 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., 2010a).

Critical Habitat

    On January 8, 2021, NMFS published a revised proposed rule for the 
Designation of Critical Habitat for the Arctic Subspecies of the Ringed 
Seal (86 FR 1452). This proposed rule revises NMFS' December 9, 2014, 
proposed designation of critical habitat for the Arctic subspecies of 
the ringed seal under the ESA. NMFS identified the physical and 
biological features essential to the conservation of the species: (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 areas of seasonal landfast (shorefast) ice 
and dense, stable pack ice, excluding any bottom-fast ice extending 
seaward from the coastline (typically in waters less than 2 m deep), 
that have undergone deformation and contain snowdrifts of sufficient 
depth, typically at least 54 cm 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, excluding any bottom-fast 
ice extending seaward from the coastline (typically in waters less than 
2 m deep); and (3) Primary prey resources to support Arctic ringed 
seals, which are defined to be Arctic cod, saffron cod, shrimps, and 
amphipods. The revised proposed critical habitat designation comprises 
a specific area of marine habitat in the Bering, Chukchi, and Beaufort 
seas, extending from mean lower low water to an offshore limit within 
the U.S. Exclusive Economic Zone, including a portion of the ONR ARA 
Study Area (86 FR 1452; January 8, 2021). See the proposed ESA critical 
habitat rule for additional detail and a map of the proposed area.
    The majority of the proposed study area was excluded from the 
proposed ringed seal critical habitat because the benefits of exclusion 
due to national security impacts outweighed the benefits of inclusion 
of this area (86 FR 1452; March 9, 2021). However, as stated in NMFS' 
second revised proposed rule for the Designation of Critical Habitat 
for the Arctic Subspecies of the Ringed Seal (86 FR 1452; March 9, 
2021), the excluded area contains one or more of the essential features 
of the Arctic ringed seal's critical habitat. However, the excluded 
area contains features that are found throughout the specific area 
designated as critical habitat (87 FR 19232, April 1, 2022), 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. A small portion of 
the study area overlaps with ringed seal critical habitat as shown in 
Figure 2. 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 activities, including impacts on prey availability.

[[Page 44348]]

[GRAPHIC] [TIFF OMITTED] TN26JY22.157

BILLING CODE 3510-22-C

Ice Seal Unusual Mortality Event

    Since June 1, 2018, elevated strandings of ringed seals, bearded 
seals, spotted seals, and several unidentified seals have occurred in 
the Bering and Chukchi Seas. The National Oceanic and Atmospheric 
Administration (NOAA), as of September 2019, have declared this event 
an Unusual Mortality Event (UME). A UME is defined under the MMPA as a 
stranding that is unexpected, involves a significant die-off of any 
marine mammal population, and demands immediate response. From June 1, 
2018 to January 7, 2022, there have been 368 dead seals reported, with 
111 stranding in 2018, 164 in 2019, and 38 in 2020, and 55 in 2021, 
which is much greater than the average number of strandings

[[Page 44349]]

of about 29 seals annually. All age classes of seals have been reported 
stranded, and a subset of seals have been sampled for genetics and 
harmful algal bloom/exposure, with a few having histopathology 
collected. Results are pending and investigation into the cause of the 
UME is ongoing, yet currently unknown. No ice seals have stranded in 
2022, at the time of this publication, yet the UME is still considered 
ongoing.
    There was a previous UME involving ice seals from 2011 to 2016, 
which was most active in 2011-2012. A minimum of 657 seals were 
affected. The UME investigation determined that some of the clinical 
signs were due to an abnormal molt, but a definitive cause of death for 
the UME was never determined. The number of stranded ice seals involved 
in this UME, and their physical characteristics, is not at all similar 
to the 2011-2016 UME, as the seals in 2018-2020 have not been 
exhibiting hair loss or skin lesions, which were a primary finding in 
the 2011-2016 UME. More detailed information is available at: https://www.fisheries.noaa.gov/alaska/marine-life-distress/2018-2022-ice-seal-unusual-mortality-event-alaska.

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, 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.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-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 ~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 and Holt, 
2013).
    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 includes a discussion of the ways that components of 
the specified activity may impact marine mammals and their habitat. The 
Estimated Take 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 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 how those impacts on individuals may or 
may not impact marine mammal species or stocks.

Description of Sound Sources

    Here, we first provide background information on marine mammal 
hearing before discussing the potential effects of the use of active 
acoustic sources on marine mammals.
    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in Hz or cycles per second. Wavelength is the distance 
between two peaks of a sound wave; lower frequency sounds have longer 
wavelengths than higher frequency sounds and attenuate (decrease) more 
rapidly in shallower water. Amplitude is the height of the sound 
pressure wave or the `loudness' of a sound and is typically measured 
using the dB scale. A dB is the ratio between a measured pressure (with 
sound) and a reference pressure (sound at a constant pressure, 
established by scientific standards). It is a logarithmic unit that 
accounts for large variations in amplitude; therefore, relatively small 
changes in dB ratings correspond to large changes in sound pressure. 
When referring to sound pressure levels (SPLs; the sound force per unit 
area), sound is referenced in the context of underwater sound pressure 
to one micropascal (1 [mu]Pa). One pascal is the pressure resulting 
from a force of one newton exerted over an area of one square meter. 
The source level (SL) represents the sound level at a distance of 1 m 
from the source (referenced to 1 [mu]Pa). The received level is the 
sound level at the listener's position. Note that all underwater sound 
levels in this document are referenced to a pressure of 1 [mu]Pa.
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. RMS is calculated by squaring all of the 
sound amplitudes, averaging the squares, and

[[Page 44350]]

then taking the square root of the average (Urick, 1983). RMS accounts 
for both positive and negative values; squaring the pressures makes all 
values positive so that they may be accounted for in the summation of 
pressure levels (Hastings and Popper, 2005). This measurement is often 
used in the context of discussing behavioral effects, in part because 
behavioral effects, which often result from auditory cues, may be 
better expressed through averaged units than by peak pressures.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. The 
compressions and decompressions associated with sound waves are 
detected as changes in pressure by aquatic life and man-made sound 
receptors such as hydrophones.
    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. Because 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 activity may be 
a negligible addition to the local environment or could form a 
distinctive signal that may affect marine mammals.
    Underwater sounds fall into one of two general sound types: 
impulsive and non-impulsive (defined in the following paragraphs). 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 in Southall et al., 2007). Please 
see Southall et al., (2007) for an in-depth discussion of these 
concepts.
    Impulsive sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986; Harris, 1998; NIOSH, 1998; ISO, 2003; ANSI, 2005) and 
occur either as isolated events or repeated in some succession. 
Impulsive sounds are all characterized by a relatively rapid rise from 
ambient pressure to a maximal pressure value followed by a rapid decay 
period that may include a period of diminishing, oscillating maximal 
and minimal pressures, and generally have an increased capacity to 
induce physical injury as compared with sounds that lack these 
features. However and as previously noted, no impulsive acoustic 
sources will be used during ONR's proposed action.
    Non-impulsive sounds can be tonal, narrowband, or broadband, brief 
or prolonged, and may be either continuous or non-continuous (ANSI, 
1995; NIOSH, 1998). Some of these non-impulsive sounds can be transient 
signals of short duration but without the essential properties of 
pulses (e.g., rapid rise time). Examples of non-impulsive sounds 
include those produced by vessels, aircraft, machinery operations such 
as drilling or dredging, vibratory pile driving, and active sonar 
sources that intentionally direct a sound signal at a target that is 
reflected back in order to discern physical details about the target. 
These active sources are used in navigation, military training and 
testing, and other research activities such as the activities planned 
by ONR as part of the proposed action. The duration of such sounds, as 
received at a distance, can be greatly extended in a highly reverberant 
environment.

Acoustic Impacts

    Please refer to the information given previously regarding sound, 
characteristics of sound types, and metrics used in this document. 
Anthropogenic sounds cover a broad range of frequencies and sound 
levels and can have a range of highly variable impacts on marine life, 
from none or minor to potentially severe responses, depending on 
received levels, duration of exposure, behavioral context, and various 
other factors. The potential effects of underwater sound from active 
acoustic sources can potentially result in one or more of the 
following: temporary or permanent hearing impairment, non-auditory 
physical or physiological effects, behavioral disturbance, stress, and 
masking (Richardson et al., 1995; Gordon et al., 2003; Nowacek et al., 
2007; Southall et al., 2007; Gotz et al., 2009). The degree of effect 
is intrinsically related to the signal characteristics, received level, 
distance from the source, and duration of the sound exposure. In 
general, sudden, high level sounds can cause hearing loss, as can 
longer exposures to lower level sounds. Temporary or permanent loss of 
hearing will occur almost exclusively for noise within an animal's 
hearing range. In this section, we first describe specific 
manifestations of acoustic effects before providing discussion specific 
to the proposed activities in the next section.
    Permanent Threshold Shift--Marine mammals exposed to high-intensity 
sound, or to lower-intensity sound for prolonged periods, can 
experience hearing threshold shift (TS), which is the loss of hearing 
sensitivity at certain frequency ranges (Finneran, 2015). TS can be 
permanent (PTS), in which case the loss of hearing sensitivity is not 
fully recoverable, or temporary (TTS), in which case the animal's 
hearing threshold would recover over time (Southall et al., 2007). 
Repeated sound exposure that leads to TTS could cause PTS. In severe 
cases of PTS, there can be total or partial deafness, while in most 
cases the animal has an impaired ability to hear sounds in specific 
frequency ranges (Kryter, 1985).
    Temporary Threshold Shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to sound (Kryter, 1985). 
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.
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent

[[Page 44351]]

physical injury (e.g., Ward, 1997). Therefore, NMFS does not consider 
TTS to constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several decibels above (a 40-dB threshold shift approximates 
PTS onset; e.g., Kryter et al., 1966; Miller, 1974) that inducing mild 
TTS (a 6-dB threshold shift approximates TTS onset; e.g., Southall et 
al., 2007). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulse sounds (such as 
impact pile driving pulses as received close to the source) are at 
least six dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level (SEL) thresholds are 15 to 20 dB 
higher than TTS cumulative SEL thresholds (Southall et al., 2007).
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. 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. 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 occurs during a time 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.
    Many studies have examined noise-induced hearing loss in marine 
mammals (see Finneran (2015) and Southall et al. (2019) for summaries). 
For cetaceans, published data on the onset of TTS are limited to the 
captive bottlenose dolphin, beluga, harbor porpoise, and Yangtze 
finless porpoise, and for pinnipeds in water, measurements of TTS are 
limited to harbor seals, elephant seals, and California sea lions. 
These studies examine hearing thresholds measured in marine mammals 
before and after exposure to intense sounds. 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, 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, 2019b, 2020a, 
2020b). 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 (Finneran et al., 2010; Kastelein et al., 
2014; Kastelein et al., 2015a; Mooney et al., 2009). This means that 
TTS predictions based on the total, cumulative SEL will overestimate 
the amount of TTS from intermittent exposures such as sonars and 
impulsive sources. Nachtigall et al. (2018) and Finneran (2018) 
describe the measurements of hearing sensitivity of multiple odontocete 
species (bottlenose dolphin, harbor porpoise, beluga, and false killer 
whale) when a relatively loud sound was preceded by a warning 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).
    Behavioral effects--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 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., 2003; Southall et al., 2007; 
Weilgart, 2007; Archer et al., 2010; Southall et al., 2021). 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). A review of marine mammal responses to anthropogenic 
sound was first conducted by Richardson (1995). More recent reviews 
(Nowacek et al., 2007; Ellison et al., 2012; Gomez et al., 2016) 
addressed studies conducted since 1995 and focused on observations 
where the received sound level of the exposed marine mammal(s) was 
known or could be estimated. Gomez et al. (2016) conducted a review of 
the literature considering the contextual information of exposure in 
addition to received level and found that higher received levels were 
not always associated with more severe behavioral responses and vice 
versa. Southall et al. (2016) states that results demonstrate that some 
individuals of different species display clear yet varied responses, 
some of which have negative implications, while others appear to 
tolerate high levels, and that responses may not be fully predictable 
with simple acoustic exposure metrics (e.g., received sound level). 
Rather, the authors state that differences among species and 
individuals along with contextual aspects of exposure (e.g., behavioral 
state) appear to affect response probability.
    The following subsections provide examples of behavioral responses 
that provide an idea of the variability in behavioral responses that 
would be expected given the differential sensitivities of marine mammal 
species to sound and the wide range of potential acoustic sources to 
which a marine mammal may be exposed. Behavioral responses that could 
occur for a given sound exposure should be determined from the 
literature that is available for each species, or extrapolated from 
closely related species when no information exists, along with 
contextual factors. 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

[[Page 44352]]

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, 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, 2003). 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; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al., 2004; Goldbogen et al., 2013). Seals exposed to non-impulsive 
sources with a received sound pressure level within the range of 
calculated exposures (142-193 dB re 1 [mu]Pa), have been shown to 
change their behavior by modifying diving activity and avoidance of the 
sound source (G[ouml]tz et al., 2010; Kvadsheim et al., 2010). 
Variations in dive behavior may reflect interruptions 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; 
Melc[oacute]n et al., 2012). In addition, behavioral state of the 
animal plays a role in the type and severity of a behavioral response, 
such as disruption to foraging (e.g., Silve et al., 2016; Wensveen et 
al., 2017). 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. Goldbogen et al. (2013) indicate that 
disruption of feeding and displacement could impact individual fitness 
and health. However, for this to be true, we would have to assume that 
an individual could not compensate for this lost feeding opportunity by 
either immediately feeding at another location, by feeding shortly 
after cessation of acoustic exposure, or by feeding at a later time. 
There is no indication this is the case, particularly since unconsumed 
prey would likely still be available in the environment in most cases 
following the cessation of acoustic exposure. Information on or 
estimates of the energetic requirements of the individuals and the 
relationship between prey availability, foraging effort and success, 
and the life history stage of the animal will help better inform a 
determination of whether foraging disruptions incur fitness 
consequences.
    Respiration naturally varies with different behaviors, and 
variations in respiration 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. Studies with captive harbor porpoises showed increased 
respiration rates upon introduction of acoustic alarms (Kastelein et 
al., 2001; Kastelein et al., 2006) and emissions for underwater data 
transmission (Kastelein et al., 2005). Various studies also have shown 
that species and signal characteristics are important factors in 
whether respiration rates are unaffected or change, 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, 2006, 
2018; Gailey et al., 2007; Isojunno et al., 2018).
    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; Foote et al., 2004), while right whales 
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; Rolland et al., 2012). Killer whales off the 
northwestern coast of the United States have been observed to increase 
the duration of primary calls once a threshold in observing vessel 
density (e.g., whale watching) was reached, which has been suggested as 
a response to increased masking noise produced by the vessels (Foote et 
al., 2004; NOAA, 2014). In some cases, however, animals may cease or 
alter sound production in response to underwater sound (e.g., Bowles et 
al., 1994; Castellote et al., 2012; Cerchio et al., 2014). Studies also 
demonstrate that even low levels of noise received far from the noise 
source can induce changes in vocalization and/or behavioral responses 
(Blackwell et al., 2013, 2015).
    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 is qualitatively 
different from the flight response, but also differs in the magnitude 
of the response (i.e., directed movement, rate of travel, etc.). 
Oftentimes avoidance is temporary, and animals return to the area once 
the noise has ceased. Acute avoidance responses have been observed in 
captive porpoises and pinnipeds exposed to a number of different sound 
sources (Kastelein et al., 2001; Finneran et al., 2003; Kastelein et 
al., 2006a; Kastelein et al., 2006b; Kastelein et al., 2015b; Kastelein 
et al., 2015c; Kastelein et al., 2018). Short-term avoidance of seismic 
surveys, low frequency emissions, and acoustic deterrents have also 
been noted in wild populations of odontocetes (Bowles et al., 1994; 
Goold, 1996; Goold and Fish, 1998; Stone et al., 2000; Morton and 
Symonds, 2002; Hiley et al., 2021) and to some extent in mysticetes 
(Malme et al., 1984; McCauley et al., 2000; Gailey et al., 2007). 
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; Teilmann 
et al., 2006).
    Forney et al. (2017) described the potential effects of noise on 
marine mammal populations with high site

[[Page 44353]]

fidelity, including displacement and auditory masking. In cases of 
Western gray whales (Weller et al., 2006) and beaked whales, 
anthropogenic effects in areas where they are resident or exhibit site 
fidelity could cause severe biological consequences, in part because 
displacement may adversely affect foraging rates, reproduction, or 
health, while an overriding instinct to remain in the area could lead 
to more severe acute effects. Avoidance of overlap between disturbing 
noise and areas and/or times of particular importance for sensitive 
species may be critical to avoiding population-level impacts because 
(particularly for animals with high site fidelity) there may be a 
strong motivation to remain in the area despite negative impacts.
    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). 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). There are limited data on flight response 
for marine mammals in water; however, there are examples of this 
response in species on land. For instance, the probability of flight 
responses in Dall's sheep Ovis dalli dalli (Frid, 2003), hauled-out 
ringed seals Phoca hispida (Born et al., 1999), Pacific brant (Branta 
bernicl nigricans), and Canada geese (B. canadensis) increased as a 
helicopter or fixed-wing aircraft more directly approached groups of 
these animals (Ward et al., 1999). 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.
    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., 2003). 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, 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; NRC, 2003; Wartzok et al., 2003). 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 impulsive sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Data on hooded seals (Cystophora cristata) indicate avoidance 
responses to signals above 160-170 dB re 1 [mu]Pa (Kvadsheim et al., 
2010), and data on grey (Halichoerus grypus) and harbor seals indicate 
avoidance response at received levels of 135-144 dB re 1 [mu]Pa 
(G[ouml]tz et al., 2010). In each instance where food was available, 
which provided the seals motivation to remain near the source, 
habituation to the signals occurred rapidly. In the same study, it was 
noted that habituation was not apparent in wild seals where no food 
source was available (G[ouml]tz et al., 2010). This implies that the 
motivation of the animal is necessary to consider in determining the 
potential for a reaction. In one study to investigate the under-ice 
movements and sensory cues associated with under-ice navigation of ice 
seals, acoustic transmitters (60-69 kHz at 159 dB re 1 [mu]Pa at 1 m) 
were attached to ringed seals (Wartzok et al., 1992a, Wartzok et al., 
1992b). An acoustic tracking system then was installed in the ice to 
receive the acoustic signals and provide real-time tracking of ice seal 
movements. Although the frequencies used in this study are at the upper 
limit of ringed seal hearing, the ringed seals appeared unaffected by 
the acoustic transmissions, as they were able to maintain normal 
behaviors (e.g., finding breathing holes).
    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 observed in marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates and efficiency (e.g., 
Beauchamp and Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 
2011). 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., 
Harrington and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998).
    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 one 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 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 response studies have been conducted on odontocete 
responses to sonar. Sperm whales were exposed to pulsed active sonar 
(1-2 kHz) at moderate source levels and high source levels, as well as 
continuously active sonar at moderate levels for which the summed 
energy (SEL) equaled the summed energy of the high source level pulsed 
sonar (Isojunno et al., 2020). Foraging behavior did not change during 
exposures to moderate source level sonar, but non-foraging behavior 
increased during exposures to high source level sonar and to the 
continuous sonar, indicating that the energy of the sound (the SEL) was 
a better predictor of response than SPL. Time of day of the exposure 
was also an important covariate in determining the amount of non-
foraging behavior, as were order effects (e.g. the SEL of the previous 
exposure); Isojunno et al. (2021) found that higher SELs reduced sperm 
whale buzzing (i.e., foraging).

[[Page 44354]]

Duration of continuous sonar activity also appears to impact sperm 
whale displacement and foraging activity (Stanistreet et al., 2022). 
During long bouts of sonar lasting up to 13 consecutive hours, 
occurring repeatedly over an 8 day naval exercise (median and maximum 
SPL = 120 dB and 164 dB), sperm whales substantially reduced how often 
they produced clicks during sonar, indicating a decrease or cessation 
in foraging behavior. Cur[eacute] et al. (2021) also found that sperm 
whales exposed to continuous and pulsed active sonar were more likely 
to produce low or medium severity responses with higher cumulative SEL. 
Specifically, the probability of observing a low severity response 
increased to 0.5 at approximately 173 dB SEL and observing a medium 
severity response reached a probability of 0.35 at cumulative SELs 
between 179 and 189 dB. These results again demonstrate that the 
behavioral state and environment of the animal mediates the likelihood 
of a behavioral response, as do the characteristics (e.g., frequency, 
energy level) of the sound source itself.
    Many of the contextual factors resulting from the behavioral 
response studies (e.g., close approaches by multiple vessels or 
tagging) would not occur during the proposed action. Odontocete 
behavioral responses to acoustic transmissions from non-impulsive 
sources used during the proposed action would likely be a result of the 
animal's behavioral state and prior experience rather than external 
variables such as ship proximity; thus, any behavioral responses are 
expected to be minimal and short term.
    To assess the strength of behavioral changes and responses to 
external sounds and SPLs associated with changes in behavior, Southall 
et al., (2007) developed and utilized a severity scale, which is a 10 
point scale ranging from no effect (labeled 0), effects not likely to 
influence vital rates (low; labeled from 1 to 3), effects that could 
affect vital rates (moderate; labeled 4 to 6), to effects that were 
thought likely to influence vital rates (high; labeled 7 to 9). 
Southall et al., (2021) updated the severity scale by integrating 
behavioral context (i.e., survival, reproduction, and foraging) into 
severity assessment. For non-impulsive sounds (i.e., similar to the 
sources used during the proposed action), data suggest that exposures 
of pinnipeds to sources between 90 and 140 dB re 1 [mu]Pa do not elicit 
strong behavioral responses; no data were available for exposures at 
higher received levels for Southall et al., (2007) to include in the 
severity scale analysis. Reactions of harbor seals were the only 
available data for which the responses could be ranked on the severity 
scale. For reactions that were recorded, the majority (17 of 18 
individuals/groups) were ranked on the severity scale as a 4 (defined 
as moderate change in movement, brief shift in group distribution, or 
moderate change in vocal behavior) or lower; the remaining response was 
ranked as a 6 (defined as minor or moderate avoidance of the sound 
source).
    Behavioral Responses to Ice Breaking 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 0.5 nm 
(0.93 km) 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). In studies by Alliston (1980; 1981), there 
was no observed change in the density of ringed seals in areas that had 
been subject to icebreaking. Alternatively, ringed seals may have 
preferentially established breathing holes in the ship tracks after the 
icebreaker 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., 2010b). 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., 1988d).
    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 (Smith, 1987). 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 Hammill, 1981; Smith and Stirling, 1975). 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., 1992a). 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., Seyle, 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).
    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

[[Page 44355]]

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 and 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). 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).
    Auditory masking-- Sound can disrupt behavior through masking, or 
interfering 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). Masking 
occurs when the receipt of a sound is interfered with by another 
coincident sound at similar frequencies and at similar or higher 
intensity, and may occur whether the sound is natural (e.g., snapping 
shrimp, wind, waves, precipitation) or anthropogenic (e.g., shipping, 
sonar, seismic exploration) in origin. 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.
    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 anthropogenic, it may be considered 
harassment when disrupting or significantly altering behavior patterns. 
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.
    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, 2009; 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 (Houser and Moore, 2014). 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).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand, 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking. 
Due to the transient nature of marine mammals to move and avoid 
disturbance, masking is not likely to have long-term impacts on marine 
mammal species within the proposed study area.
    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 160 to 489 ft (49 to 149 m). 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

[[Page 44356]]

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 (Alliston, 1980; 1981) 
suggested that ringed seals might preferentially establish breathing 
holes in ship tracks after vessels move through the area. 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

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determinations.
    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 disruption of behavioral patterns and/or TTS for individual marine 
mammals resulting from exposure to ONR's acoustic sources. 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 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). For the proposed IHA, ONR employed an advanced model known as 
the Navy Acoustic Effects Model (NAEMO) for assessing the impacts of 
underwater sound. 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).
    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, 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 (referenced 
to 1 micropascal (re 1 [mu]Pa)) for continuous (e.g., vibratory pile-
driving, drilling) and above RMS SPL 160 dB re 1 [mu]Pa (rms) for non-
explosive impulsive (e.g., seismic airguns) or intermittent (e.g., 
scientific sonar) sources.
    In this case, NMFS is proposing to adopt the Navy'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 Navy's dose response functions were developed to 
estimate take from sonar and similar transducers, but are not 
applicable to ice breaking. 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., 2013a; Houser et al., 2013b). 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 1m; 
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

[[Page 44357]]

exposure to sonar (Antunes et al., 2014; Houser et al., 2013b; Miller 
et al., 2011; Miller et al., 2014; Miller et al., 2012). 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 6 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, 
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 
[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 Navy 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 2.7 nm (5 km) for pinnipeds and 5.4 nm (10 km) for beluga whales 
(Table 5). As some of the on-site drifting sources could come closer 
together, the drifting source cutoffs applied were 5.4 nm (10 km) for 
pinnipeds and 10.8 nm (20 km) 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 2.7 nm (5 km), and range to TTS threshold for both under 15 
m (Table 5).

                                           Table 5--Thresholds\1\ and Cutoff Distances for Sources by Species
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Drifting
                                                  Fixed source       source
                                  Behavioral       behavioral      behavioral       Behavioral     Ice breaking
           Species               threshold for      threshold       threshold     threshold for    source cutoff     TTS threshold       PTS threshold
                                 non-impulsive       cutoff          cutoff        ice breaking    distance \3\
                               acoustic sources   distance \3\    distance \3\       sources           (km)
                                                      (km)            (km)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ringed Seal..................  Pinniped Dose                  5              10  120 dB re 1                  <5  181 dB SEL          201 dB SEL
                                Response                                          [mu]Pa step                      cumulative.         cumulative.
                                Function \2\.                                     function.
Beluga Whale.................  Mid-Frequency                 10              20  120 dB re 1                 <15  178 dB SEL          198 dB SEL
                                BRF dose                                          [mu]Pa step                      cumulative.         cumulative.
                                Response                                          function.
                                Function \2\.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ 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.
\2\ See Figure 6-1 in application.
\3\ Take is not estimated to occur beyond these cutoff distances, regardless of the received level.

    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). ONR's 
proposed activity includes the use of non-impulsive acoustic sources; 
however, Level A harassment is not expected as a result of the proposed 
activities 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: 
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 thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: L0-pk,flat: 219     Cell 2: LE, LF,24h: 199 dB
                                          dB; LE, LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: L0-pk,flat: 230     Cell 4: LE, MF,24h: 198 dB
                                          dB; LE, MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: L0-pk,flat: 202     Cell 6: LE, HF,24h: 173 dB
                                          dB; LE, HF,24h: 155 dB.

[[Page 44358]]

 
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: L0-pk,flat: 218     Cell 8: LE, PW,24h: 201 dB
                                          dB; LE, PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: L0-pk,flat: 232     Cell 10: LE, OW,24h: 219 dB
                                          dB; LE, OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric 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 are recommended for consideration.
Note: Peak sound pressure level (L0-pk) has a reference value of 1 [micro]Pa, and weighted cumulative sound
  exposure level (LE,) has a reference value of 1[mu]Pa\2\s. In this Table, thresholds are abbreviated to be
  more reflective of International Organization for Standardization standards (ISO 2017). The subscript ``flat''
  is being included to indicate peak sound pressure are flat weighted or unweighted within the generalized
  hearing range of marine mammals (i.e., 7 Hz to 160 kHz). 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 weighted
  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 thresholds will be exceeded.

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

[[Page 44359]]

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 eight 
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 one year of transmitting. 
Therefore, the potential for an icebreaking cruise on CGC Healy was 
conservatively analyzed within this request for an IHA. As the R/V 
Sikuliaq is not expected to be ice breaking, acoustic noise created by 
ice breaking 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 sound pressure level (root mean square [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 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 (Full Power) and 3/10 (Quarter Power) Ice
                 Coverage Ice Breaking on the CGC Healy
------------------------------------------------------------------------
     Frequency (Hz)       8/10 source level (dB)  3/10 source level (dB)
------------------------------------------------------------------------
                   25                      189                      187
                   50                      188                      182
                  100                      189                      179
                  200                      190                      177
                  400                      188                      175
                  800                      183                      170
                 1600                      177                      166
                 3200                      176                      171
                 6400                      172                      168
                12800                      167                      164
------------------------------------------------------------------------

    For non-impulsive sources, NAEMO calculates the SPL and SEL for 
each active emission during an event. This is done by taking the 
following factors into account over the propagation paths: bathymetric 
relief and bottom types, sound speed, and attenuation contributors such 
as absorption, bottom loss, and surface loss. Platforms such as a ship 
using one or more sound sources are modeled in accordance with relevant 
vehicle dynamics and time durations by moving them across an area whose 
size is representative of the testing event's operational area.

Marine Mammal Occurrence and Take Estimation

    In this section we provide information about the occurrence of 
marine mammals, including density or other relevant information that 
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 et al. (2006) 
and Kaschner (2004). Density for beluga whales was not distinguished by 
stock and varied throughout the project area geographically and 
monthly; the range of densities in the project area during September I 
shown in Table 8. The density estimates for ringed seals are based on 
the habitat suitability modeling by Kaschner et al., (2006) and 
Kaschner (2004) and shown in Table 8 as well.

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


[[Page 44360]]

    Take of all species would occur by Level B harassment only. NAEMO 
estimated for potential TTS exposure and predicted one exposure of 
ringed seals may occur as a result of the proposed activities. 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.
    Density estimates for beluga whales are equal as estimates were not 
distinguished by stock (Kaschner et al., 2006; Kaschner, 2004). 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--Requested Take by Level B harassment
----------------------------------------------------------------------------------------------------------------
                                                                                 Total proposed    Percentage of
                                Non-impulsive     Icebreaking     Icebreaking    authorized take       stock
           Species            active acoustics   (behavioral)        (TTS)     ------------------  requested for
                                (behavioral)                                     Behavioral/TTS      take \1\
----------------------------------------------------------------------------------------------------------------
Beluga whale--Beaufort Sea                 134              11               0             145/0           0.369
 Stock......................
Beluga whale--Eastern                      134              11               0             145/0            1.09
 Chukchi Sea Stock..........
Ringed seal.................             2,839             538               1           3,377/1            1.97
----------------------------------------------------------------------------------------------------------------
\1\ Percentage of stock taken calculated based on proportion of number of Level B takes per the stock population
  estimate provided in Table 3-1 in the application.

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 NDAA for FY 2004 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.

Mitigation for Marine Mammals and Their Habitat

    The Navy would be required to abide by the mitigation measures 
below. These measures are expected to: further minimize the likelihood 
of ship strikes; reduce the likelihood that marine mammals are exposed 
to sound levels during acoustic source deployment that would be 
expected to result in TTS or more severe behavioral responses and also 
to ensure that there are no other interactions between the deployed 
gear and marine mammals, and; further ensure that there are no impacts 
to subsistence uses.
    Ships operated by or for the Navy have at least one personnel 
assigned to stand watch at all times, day and night, when moving 
through the water. Watch personnel must be trained through the U.S. 
Navy Marine Species Awareness Training Program, which standardizes 
watch protocols and trains personnel in marine species detection to 
prevent adverse impacts to marine mammal species. While in transit, 
ships must be alert at all times, use extreme caution and proceed at a 
safe speed such that the ship can take proper and effective action to 
avoid a collision with any marine mammals.
    During mooring or UUV deployment, visual observation would start 15 
minutes prior to and continue throughout the deployment within the 
mitigation zone of 180 ft (55 m, roughly one ship length) around the 
deployed mooring. Deployment will stop if a marine mammal is visually 
detected within the exclusion zone. Deployment will re-commence if any 
one of the following conditions are met: (1) The animal is observed 
exiting the exclusion zone, (2) the animal is thought to have exited 
the exclusion zone based on its course and speed, or (3) the exclusion 
zone has been clear from any additional sightings for a period of 15 
minutes for pinnipeds and 30 minutes for cetaceans.
    Ships would avoid approaching marine mammals head-on and would 
maneuver to maintain a mitigation zone of 500 yards (yd; 457 m) around 
observed cetaceans, and 200 yd (183 m) around all other marine mammals, 
provided it is safe to do so in ice-free waters. Ships captains and 
subsistence whalers would also maintain at-sea communication to avoid 
conflict of ship transit with hunting activity.
    If a marine mammal species for which take is not authorized is 
encountered or observed within the mitigation zone, or a species for 
which authorization was granted but the authorized number of takes have 
been met, activities must cease. Activities may not resume until

[[Page 44361]]

the animal is confirmed to have left the area.
    These requirements do not apply if a vessel's safety is at risk, 
such as when a change of course would create an imminent and serious 
threat to safety, person, or vessel, and to the extent that vessels are 
restricted in their ability to maneuver. No further action is necessary 
if a marine mammal other than a cetacean continues to approach the 
vessel after there has already been one maneuver and/or speed change to 
avoid the animal. Avoidance measures should continue for any observed 
cetacean in order to maintain a mitigation zone of 500 yd (457 m).
    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, and 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 action; 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.
    While underway, the ships (including non-Navy ships operating on 
behalf of the Navy) utilizing active acoustics will have at least one 
watch person during activities. Watch personnel must undertake 
extensive training through the Navy's Marine Species Awareness 
Training. Their duties may be performed in conjunction with other job 
responsibilities, such as navigating the ship or supervising other 
personnel. While on watch, personnel employ visual search techniques, 
including the use of binoculars, using a scanning method in accordance 
with the U.S. Navy Marine Species Awareness Training or civilian 
equivalent. A primary duty of watch personnel is to detect and report 
all objects and disturbances sighted in the water that may be 
indicative of a threat to the ship and its crew, such as debris, or 
surface disturbance. Per safety requirements, watch personnel also 
report any marine mammals sighted that have the potential to be in the 
direct path of the ship as a standard collision avoidance procedure.
    While underway, the ships (including non-Navy ships operating on 
behalf of the Navy) utilizing active acoustics and towed in-water 
devices will have at least one watch person during activities. While 
underway, watch personnel must be alert at all times and have access to 
binoculars. Each day, the following information should be recorded:
     Vessel name;
     Watch personnel names and affiliations;
     Effort type (i.e., transit or deployment); and
     Environmental conditions (at the beginning of watch 
personnel shift and whenever conditions changed significantly), 
including Beaufort Sea State and any other relevant weather conditions 
including cloud cover, fog, sun glare, and overall visibility to the 
horizon.
    Watch personnel must use standardized data collection forms, 
whether electronic or hard copy, as well as distinguish between marine 
mammal sightings that occur during ship transit or acoustic source 
deployment. Upon visual observation of a marine mammal, the following 
information would be recorded:
     Date/time of sighting;
     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;
     Location (latitude/longitude) of sighting;
     Estimated number of animals (high/low/best)
     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);
     Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping, diving, feeding, 
traveling; as explicit and detailed as possible; length of time the 
animal was observed within the harassment zone; note any observed 
changes in behavior);
     Distance from ship to animal;
     Direction of animal's travel relative to the vessel
     Platform activity at time of sighting (i.e., transit, 
deployment); and
     Weather conditions (i.e., Beaufort Sea State, cloud 
cover).
    The U.S. 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) 
(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

[[Page 44362]]

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 and 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.
    If any injury or death of a marine mammal is observed during the 
2022-2023 ARA, the Navy will immediately halt the activity and report 
the incident to the Office of Protected Resources, NMFS, and the Alaska 
Regional Stranding Coordinator, NMFS. The following information must be 
provided:
     Time, date, and location of the discovery;
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal(s) was 
discovered (e.g., deployment of moored or drifting sources or by 
transiting vessel).
    ONR will provide NMFS OPR and AKR with a draft monitoring report 
within 90 days of the conclusion of each research cruise, or sixty days 
prior to the issuance of any subsequent IHA for this project, whichever 
comes first. The draft monitoring report will include data regarding 
acoustic source use and any mammal sightings or detection documented. 
The report will include the estimated number of marine mammals taken 
during the activity. The report will also include information on the 
number of shutdowns recorded. If no comments are received from NMFS 
within 30 days of submission of the draft final report, the draft final 
report will constitute the final report. If comments are received, a 
final report must be submitted within 30 days after receipt of 
comments.

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 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. However, 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 affect annual rates of ringed seal survival and 
recruitment that may threaten population recovery or exacerbate the 
ongoing UME.
    A small portion of the proposed ARA 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. 
Displacement of ringed seals from the proposed ARA study area would 
likely not interfere with their ability to access necessary habitat 
features. Therefore, we expect minimal impacts to any displaced ringed 
seals as similar necessary habitat features would still be available 
nearby.
    The proposed ARA study area also overlaps with a beluga whale 
migratory BIA. Due to the small amount of overlap between the BIA 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 belugas. Shutdown zones will reduce 
the potential for Level A harassment of belugas and ringed seals, as 
well as the severity of any Level B

[[Page 44363]]

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 ARA 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 behavioral modifications are expected to 
result from these proposed activities;
     Impacts to marine mammal prey or habitat will be minimal 
and short term.
    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 (formally Barrow) identified the primary resources 
used for subsistence and the locations for harvest (Stephen R. Braund & 
Associates, 2010), including terrestrial mammals (caribou, moose, wolf, 
and wolverine), birds (geese and eider), fish (Arctic cisco, Arctic 
char/Dolly Varden trout, and broad whitefish), and marine mammals 
(bowhead whale, ringed seal, 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 100km 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 take is approximately 110 nm (204 
km) from land. This ensures a significant standoff distance from any 
subsistence hunting area. The closest distance to subsistence hunting 
(70 nm, or 130 km) is well the largest distance from the sound sources 
in use at which behavioral harassment would be expected to occur (20 
km) 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 chief scientist for AMOS gave a 
virtual briefing on ONR research planned for 2022-2023 Alaska Eskimo 
Whaling Commission (AEWC) meeting in February 2022. This briefing 
communicated the lack of effect on subsistence hunting due to the 
distance of the sources from hunting areas. ONR scientists also attend 
Arctic Waterways Safety Committee (AWSC) and AEWC meetings regularly to 
discuss past, present, and future ARA. While no take is anticipated to 
result during transit, points of contact for at-sea communication will 
also be established between ship captains and whalers 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 Endangered Species Act of 1973 (ESA: 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 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 ONR for conducting their fifth year of ARA in the 
Beaufort and eastern Chukchi Seas from September 2022--September 2023, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. A draft of the proposed IHA can be found 
at: www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

[[Page 44364]]

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, one-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 
Activities section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activities 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 one 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: July 20, 2022.
Shannon Bettridge,
Chief, Marine Mammal and Sea Turtle Conservation Division,Office of 
Protected Resources, National Marine Fisheries Service.
[FR Doc. 2022-15937 Filed 7-25-22; 8:45 am]
BILLING CODE 3510-22-P