[Federal Register Volume 86, Number 160 (Monday, August 23, 2021)]
[Notices]
[Pages 47065-47087]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-18070]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB239]


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 4)

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

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

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SUMMARY: NMFS has received a request from Office of Naval Research 
(ONR) for authorization to take marine mammals incidental to Arctic 
Research Activities in the Beaufort Sea and eastern Chukchi Sea. 
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting 
comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-time, 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 authorizations and agency responses will be 
summarized in the final notice of our decision. ONR's activities are 
considered military readiness activities pursuant to the MMPA, as 
amended by the National

[[Page 47066]]

Defense Authorization Act for Fiscal Year 2004 (NDAA).

DATES: Comments and information must be received no later than 
September 22, 2021.

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: Kelsey Potlock, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the 2021-2022 IHA 
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 United States (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 issued or, if the taking is limited to harassment, a 
notice of a proposed incidental take authorization may be 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 NDAA (Pub. L. 108-136) removed the ``small numbers'' and 
``specified geographical region'' limitations indicated above and 
amended the definition of ``harassment'' as it applies 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, 
we 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 our own 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, we 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 our own 
FONSI in support of the issuance of an IHA (84 FR 50007; September 24, 
2019).
    In 2020, the Navy submitted a request for a renewal of the 2019 
IHA. Prior to issuing the renewal IHA, NMFS reviewed ONR's application 
and determined that the proposed action was identical to that 
considered in the previous IHA. Because no significantly new 
circumstances or information relevant to any environmental concerns had 
been identified, NMFS determined that the preparation of a new or 
supplemental NEPA document was not necessary and relied on the 
supplement EA and FONSI from 2019 when issuing the renewal IHA in 2020 
(85 FR 41560; July 10, 2020).
    For this proposed action, NMFS plans to adopt the Navy's 2021 
supplemental EA provided our independent evaluation of the document 
finds that it includes adequate information analyzing the effects on 
the human environment of issuing the IHA. The Navy's supplemental EA is 
available at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.
    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 June 4, 2021, NMFS received a request from ONR for an IHA to 
take marine mammals incidental to Arctic Research Activities in the 
Beaufort and eastern Chukchi Seas. ONR's 2021-2022 IHA application was 
deemed adequate and complete on August 4, 2021. ONR's request is for 
take of beluga whales (Delphinapterus leucas; two stocks) and ringed 
seals (Pusa hispida hispida) by Level B harassment only. Neither ONR 
nor NMFS expects serious injury or mortality to result from this 
activity and, therefore, an IHA is appropriate.
    This proposed IHA would cover the fourth 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) 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 (early October 2021 to early October 2022). The larger 
project involves several scientific objectives that support the Arctic 
and Global Prediction Program, as well as the Ocean Acoustic Program 
and the Naval Research Laboratory, for which ONR is the parent command. 
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).

[[Page 47067]]

Description of Proposed Activity

Overview

    ONR's Arctic Research Activities include scientific experiments to 
be conducted in support of the programs named above. Specifically, the 
project includes the Arctic Mobile Observing System (AMOS), Ocean 
Acoustics field work, and Naval Research Laboratory (NRL) experiments 
in the Beaufort and Chukchi Seas. Project activities involve acoustic 
testing during cruises (two planned) 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 as well as a towed 
source (see details below on the Shallow Water Integrate Mapping 
System) from the Research Vessel (R/V) Sikuliaq and another vessel, 
most likely the U.S. Coast Guard Cutter (CGC) HEALY. Underwater sound 
from the acoustic sources may result in behavioral harassment of marine 
mammals.

Dates and Duration

    This proposed action would occur from early October 2021 through 
early October 2022. The activities analyzed in this proposed IHA would 
begin in early October 2021, with a tentative sail date of October 3, 
2021 using the R/V Sikuliaq for the first cruise. During this first 
cruise, several acoustic sources would be deployed from the ship. 
Limited at-sea testing of sources would occur. Around the same time, 
some of the sources previously deployed during past projects would be 
reactivated. These sources would stay active for around two months and 
then would be deactivated via satellite. In the spring of 2022, new NRL 
acoustic sources would be deployed by aircraft (likely a fixed-wing 
Twin Otter or another single-engine aircraft) and subsequently 
activated. These would remain active for approximately five months and 
then would be deactivated via satellite. During the fall of 2022, 
another research cruise would begin (likely using the CGC HEALY). The 
most likely months for this cruise would be September or October 2022.
    The cruise utilizing the R/V Sikuliaq is estimated to consist of 
approximately 30 days (October 2021--October 2021) at sea. The second 
vessel (likely the CGC HEALY) would operate in the fall of 2022 for 
approximately six weeks within a two-month period (September or October 
2022). However, this proposed action, if finalized, would only be valid 
for a period of one year, from approximately October 2021-October 2022.
    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 2021-
2022 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 coring of bottom sediments within the project area, the 
deployment of weather balloons, the deployment of on-ice measurement 
systems to collect weather data, the deployment and use of unmanned 
aerial systems (UAS), the mooring and use of fixed receiving arrays 
(passive acoustic arrays) and oceanographic sensors, and the use and 
deployment of drifting oceanographic sensors.

Specific 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). This proposed project area is further north from the project 
area that was previously considered in the first IHA (83 FR 48799, 
September 27, 2018), the second IHA (84 FR 50007, September 24, 2019), 
and the subsequent renewal to the second IHA (85 FR 53333, August 28, 
2020). The proposed action would occur primarily in the Beaufort Sea; 
however, the Navy has included the Chukchi Sea in their 2021-2022 IHA 
application and analysis to account for any drifting of buoys with 
active sources.
    The study area consists of a deep-water area approximately 110 
nautical miles (nm; 204 kilometers (km)) north of the Alaska coastline. 
The total area of the proposed project site is 294,975 square miles 
(mi\2\; 763,981 square kilometers (km\2\)). The closest distance of any 
leave-behind source (where a majority of the take associated with this 
proposed action could occur) is 240 mi (386 km) or more from the Alaska 
coastline. This is exclusive to any de minimis sources described below 
in the Detailed Description of Specific Activity. Some other 
activities, such as the use of gliders, unmanned undersea vehicles 
(UUVs), or some on-site activities could occur closer to Alaska, around 
110 mi (177 km) from the coastline; however, little take and impacts 
are attributed to these as they are primarily de minimis acoustic 
sources. A map of the proposed project area and the locations of the 
moored and deployed buoys is shown in Figure 1.
BILLING CODE 3510-22-P

[[Page 47068]]

[GRAPHIC] [TIFF OMITTED] TN23AU21.003

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 (see 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.

[[Page 47069]]

    The AMOS project constitutes the development of a new system 
involving very low (35 hertz (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 gliders and 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 an important 
method of observing ocean warming, and the continued development of 
these types of acoustic sources would allow for characterization of 
larger areas. 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.
    Additional leave-behind sources would be deployed by aircraft and 
would support the NRL project for rapid environmental characterization. 
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). NRL currently has four active buoys covered under the 
current IHA that is active until September 13, 2021 (85 FR 53333; 
August 28, 2020). The proposed action described herein would allow ONR 
to re-activate these buoys for observation in the far north from 
October to December 2021, as well as a deployment of additional sources 
to be active from March to August 2022.
    ONR is also supporting a project called UpTempO that would use two 
drifting buoys to observe oceanographic conditions in the seasonal ice 
zone. These buoys would not have any active acoustic sources and no 
take is expected to occur in association with the project. They would 
be deployed by ONR during the October 2021 and fall 2022 cruises.
    In contrast to past IHA applications for ONR Arctic Research 
Activities, icebreaking would not occur as part of this proposed 
action. The manner of deployment (by ships, buoys, UUVs, or other 
related methods) as well as the transit of the vessels is not expected 
to contribute to take. ONR's proposed action would only utilize non-
impulsive acoustic sources, although not all sources will cause take of 
marine mammals. Furthermore, any marine mammal takes would only arise 
from the operation of non-impulsive active sources.
    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 October 2021, 
and conduct testing of acoustic sources during the cruise, as well as 
leave sources behind to operate as a year-round navigation system 
observation. The ship to be used in the fall of 2022 is yet to be 
determined. The most probable option would be the CGC HEALY, so that 
ship is described below.
    The R/V Sikuliaq has a maximum speed of approximately 12 knots with 
a cruising speed of 11 knots (University of Alaska Fairbanks, 2014). 
The R/V Sikuliaq is not an ice-breaking ship, but an ice-strengthened 
ship. The CGC HEALY travels at a maximum speed of 17 knots with a 
cruising speed of 12 knots (United States Coast Guard, 2013), and a 
maximum speed of 3 knots when traveling through 3.5 feet (ft; 1.37 
meters (m)) of sea ice (Murphy, 2010). No icebreaking activity is 
anticipated to occur during this proposed action. Both vessels would 
depart from and return to Nome, Alaska.
    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 unmanned surface, underwater, and air 
vehicles;
     Deployment of drifting buoys, with or without acoustic 
sources; or,
     Recovery of equipment.
    Additional oceanographic measurements would be made using ship-
based systems, including the following:
     Modular Microstructure Profiler, a tethered profiler that 
would measure oceanographic parameters within the top 984 ft (300 m) of 
the water column;
     Shallow Water Integrate Mapping System, a winched towed 
body with a Conductivity Temperature Depth sensor, upward and downward 
looking Acoustic Doppler Current Profilers (ADCPs), and a temperature 
sensor within the top 328 ft (100 m) of the water column;
     Three dimensional Sonic Anemometer, which would measure 
wind stress from the foremast of the ship; and,
     Surface Wave Instrument Float with Tracking are freely 
drifting buoys measuring winds, waves, and other parameters with 
deployments spanning from hours to days.
Moored and Drifting Acoustic Sources
    AMOS Project (ONR)--During the October 2021 cruise, acoustic 
sources would be deployed from the ship on UUVs or drifting buoys. 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 and 900 Hz 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. 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. 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 2022 cruise; a subsequent application would be 
provided by ONR depending on the scientific plan associated with that 
cruise.
    Rapid Environmental Characterization (NRL)--NRL deployed six 
drifting sources under the current 2020 IHA for ONR Arctic Research 
Activities (85 FR 53333; August 28, 2020). A maximum of three may still 
be available for reactivation in October 2021 and transmission until 
December 2021. The purpose of these sources is near-real time 
environmental characterization, which is accomplished by communicating 
information from the drifting buoys to a satellite. These buoys were 
deployed in the ice (via fixed-wing aircraft) for purposes of buoy 
stability, but eventually drift in open water. An additional set of 
five buoys would be deployed on the ice in March 2022

[[Page 47070]]

using fixed- or rotary-wing aircraft and transmit until August 2022. 
The sources can be turned on or off remotely in accordance with 
permitting requirements (i.e., outside of periods with an active IHA as 
to not cause potential unauthorized take of marine mammals), or when 
they drift outside of the project location.
    The acoustic parameters of sources for the AMOS and NRL projects 
discussed for this proposed action are given in Table 1. A distinction 
is made between sources that would have limited testing when the ship 
is on-site, and leave behind sources that would transmit for the full 
year.

                                Table 1--Characteristics of the Modeled Acoustic Sources Used During the Proposed Action
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Sound
                                                     pressure level
            Source name              Frequency (Hz)      (dB re 1     Pulse length     Duty cycle             Source type                  Usage
                                                     [micro]Pa at 1     (seconds)       (percent)
                                                         m) \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
AMOS Navigation Sources (LF) [leave         900-950             180              30              <1  Moored......................  7 sources
 behind].                                                                                                                           transmitting 30
                                                                                                                                    seconds every 4
                                                                                                                                    hours.
AMOS Navigation sources (LF) [on-           900-950             180              30               4  Moving......................  2 sources,
 site; UUV and ship].                                                                                                               transmitting 5 times
                                                                                                                                    an hour with 30 sec
                                                                                                                                    pulse length.
AMOS Navigation sources (LF)                900-950             180              30              <1  Drifting....................  1 source,
 [onsite; buoy].                                                                                                                    transmitting every 4
                                                                                                                                    hours.
AMOS VLF Navigation Sources........              35             190             600               1  Ship-deployed...............  2 times per day.
NRL Real-Time Sensing Sources             900-1,000             184              30              <1  Drifting....................  3 sources
 (2021).                                                                                                                            transmitting 30
                                                                                                                                    seconds every 6
                                                                                                                                    hours.
NRL Real-Time Sensing Sources             850-1,050             184              60              <1  Drifting....................  5 sources
 (2022).                                                                                                                            transmitting 1
                                                                                                                                    minute every 8
                                                                                                                                    hours.
WHOI \2\ micromodem (on-site; UUV).        8-14 kHz             185               4              10  Moving......................  Medium duty cycle
                                                                                                                                    acoustic
                                                                                                                                    communications.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ dB re 1 [micro]Pa at 1 m= decibels referenced to 1 micropascal at 1 meter.
\2\ WHOI = Woods Hole Oceanographic Institution.

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--De minimis sources have 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). The drifting oceanographic sensors described below 
use only de minimis sources and are not anticipated to have the 
potential for impacts on marine mammals or their habitat. 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 Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                Sound pressure
                                                                level (dB re 1   Pulse length     Duty cycle                                De minimis
         Source name                Frequency  range (kHz)      [micro]Pa at 1     (seconds)       (percent)           Beamwidth          Justification
                                                                      m)
--------------------------------------------------------------------------------------------------------------------------------------------------------
PIES.........................  12.............................         170-180           0.006           <0.01  45.....................  Extremely low
                                                                                                                                          duty cycle,
                                                                                                                                          low source
                                                                                                                                          level, very
                                                                                                                                          short pulse
                                                                                                                                          length.
ADCP.........................  >200, 150, or 75...............             190          <0.001            <0.1  2.2....................  Very low pulse
                                                                                                                                          length, narrow
                                                                                                                                          beam, moderate
                                                                                                                                          source level.
Chirp sonar..................  2-16...........................             200            0.02              <1  narrow.................  Very short
                                                                                                                                          pulse length,
                                                                                                                                          low duty
                                                                                                                                          cycle, narrow
                                                                                                                                          beam width.
EMATT........................  700-1,100 Hz and 1100-4,000 Hz.            <150             N/A          25-100  Omni...................  Very low source
                                                                                                                                          level.
Coring system................  25-200.........................         158-162          <0.001              16  Omni...................  Very low source
                                                                                                                                          level.\2\
CTD \1\ attached Echosounder.  5-20...........................             160           0.004               2  Omni...................  Very low source
                                                                                                                                          level.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ CTD = Conductivity Temperature Depth.
\2\ Within sediment; not within the water column.


[[Page 47071]]

    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. The 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.
    Fifteen autonomous floats (Air-Launched Autonomous Micro Observer) 
would be deployed during the proposed action to measure seasonal 
evolution of the ocean temperature and salinity, as well as currents. 
They would be deployed on the eastern edge of the Chukchi Sea in water 
less than 3,280 ft (1,000 m) deep. Three autonomous floats would act as 
virtual moorings by originating on the seafloor, then moving up the 
water column to the surface and returning to the seafloor. The other 12 
autonomous floats would sit on the seafloor and at intervals begin to 
move towards the surface. At programmed intervals, a subset of the 
floats would release anchors and begin their profiling mission. Up to 
15 additional floats may be deployed by ships of opportunity in the 
Beaufort Gyre.
    The UpTempO project would deploy two surface buoys. There is a 
conductivity-temperature sensor pair attached to the hull to measure 
sea surface temperature and sea surface salinity.
    The drifting 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.
    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 multi-beam sonars.
    Additionally, Beaufort Gyre Exploration Project moorings BGOS-A and 
BGOS-B would be augmented with McLane Moored Profilers. BGOS-A and 
BGOS-B would be placed on existing Woods Hole Oceanographic Institute 
(WHOI) moorings. The two BGOS moorings would provide measurements near 
the Northwind Ridge, with considerable latitudinal distribution. 
Existing deployments of Nortek Acoustic Wave and Current Profilers on 
BGOS-A and BGOS-B would also be continued as part of the proposed 
action.
    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.
    Fixed Receiving Arrays--Horizontal and vertical arrays may be used 
to receive acoustic signals, if they are available. Examples are the 
Single Hydrophone Recording Units and Autonomous Multichannel Acoustic 
Recorder. Such arrays would be moored to the seafloor and remain in 
place throughout the activity.
    These are passive acoustic sensors and therefore are not 
anticipated to have the potential for impacts on marine mammals or 
their habitat.
    Activities Involving Aircraft and Unmanned Air Vehicles--The 
deployment of the NRL sources in 2022 would be accomplished by using 
aircraft that would land on the ice. Flights would be conducted with a 
Twin Otter aircraft or a single engine alternative that would be 
quieter. Flights would transit at 1,500 ft or 10,000 ft (457 m or 3,048 
m) above sea level. Twin Otters have flight speeds of 80 to 160 knots 
(148 to 296 kilometers per hour (kph)), a typical survey speed of 90 to 
110 knots (167 to 204 kph), 66 ft (20 m) wingspan, and a total length 
of 26 ft (8 m) (U.S. Department of Commerce and National Oceanographic 
and Atmospheric Administration, 2015). At a distance of 2,152 ft (656 
m) away, the received pressure levels of a Twin Otter range from 80 to 
98.5 A[hyphen]weighted decibels (expression of the relative loudness in 
the air as perceived by the human ear) and frequency levels ranging 
from 20 Hz to 10 kHz, though they are more typically in the 500 Hz 
range (Metzger, 1995). Once on the floating ice, the team would drill 
holes with up to a 10-inch (in; 25.4 centimeters (cm)) diameter to 
deploy scientific equipment (e.g., source, hydrophone array, EMATT) 
into the water column.
    The proposed action includes the use of an Unmanned Aerial System 
(UAS). The UAS would be utilized for aid of navigation and to confirm 
and study ice cover. The UAS would be deployed ahead of the ship to 
ensure a clear passage for the vessel and would have a maximum flight 
time of 20 minutes. The UAS would not be used for marine mammal 
observations or hover close to the ice near marine mammals. There would 
be no videotaping or picture taking of marine mammals as part of this 
proposed action. The UAS that would be used during the proposed action 
is a small commercially available system that generates low sound 
levels and is smaller than military grade systems. The dimensions of 
the proposed UAS are, 11.4 in, (29 cm) by 11.4 in (29 cm) by 7.1 in (18 
cm) and weighs only 2.5 pounds (lbs.; 1.13 kilograms (kg)). The UAS can 
operate up to 984 ft (300 m) away, which would keep the device in close 
proximity to the ship. The planned operation of the UAS is to fly it 
vertically above the ship to examine the ice conditions in the path of 
the ship and around the area (i.e., not flown at low altitudes around 
the vessel). Currently acoustic parameters are not available for the 
proposed models of UASs to be utilized in the proposed action. As 
stated above these systems are very small and are similar to a remote 
control helicopter. It is likely marine mammals would not hear the 
device since the noise generated would likely not be audible from 
greater than 5 ft (1.5 m) away (Christiansen et al., 2016).
    All aircraft (manned and unmanned) would be required to maintain a 
minimum separation distance of 1,000 ft (305 m) from any pinnipeds 
hauled out on the ice. Therefore, no take of marine mammals is 
anticipated from these activities.
    On-Ice Measurement Systems--On-ice measurement systems would be 
used to collect weather data. These would include an Autonomous Weather 
Station and an Ice Mass Balance Buoy. The Autonomous Weather Station 
would be deployed on a tripod; the tripod has insulated foot platforms 
that are frozen into the ice. The system would consist of an 
anemometer, humidity sensor, and pressure sensor. The Autonomous 
Weather Station also includes an altimeter that is de minimis due to 
its very high frequency (200 kHz). The Ice Mass Balance Buoy is a 20

[[Page 47072]]

ft (6 m) sensor string, which is deployed through a 2 in (5 cm) hole 
drilled into the ice. The string is weighted by a 2.2 lbs. (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, and will drift with the 
ice, making measurements, until their host ice floes melt, thus 
destroying the instruments (likely in summer, roughly one year after 
deployment). After the on-ice instruments are destroyed they cannot be 
recovered, and would sink to the seafloor as their host ice floes 
melted.
    All personnel conducting experiments on the ice would be required 
to maintain a minimum separation distance of 1,000 ft (305 m) from any 
pinnipeds hauled out on the ice. Therefore, no take of marine mammals 
is anticipated from these activities.
    Bottom Interaction Systems--Coring of bottom sediment could occur 
anywhere within the project location to obtain a more complete 
understanding of the Arctic environment. Coring equipment would take up 
to 50 samples of the ocean bottom in the study location annually. The 
samples would be roughly cylindrical, with a 3.1 in (8 cm) diameter 
cross-section area; the corings would be between 10 and 20 ft (3 and 6 
m) long. Coring would only occur during research cruises, during the 
summer or early fall. The coring equipment moves very slowly through 
the muddy bottom, at a speed of approximately 1 m per hour, and would 
not create any detectable acoustic signal within the water column, 
though very low levels of acoustic transmissions may be created in the 
mud (refer back to Table 2). The source levels of the coring equipment 
are so low that take of marine mammals from acoustic exposure is not 
considered a potential outcome of this activity.
    Weather Balloons--To support weather observations, up to forty 
Kevlar or latex balloons would be launched per year for the duration of 
the proposed actions. These balloons and associated radiosondes (a 
sensor package that is suspended below the balloon) are similar to 
those that have been deployed by the National Weather Service since the 
late 1930s. When released, the balloon is approximately 5 to 6 ft (1.5 
to 1.8 m) in diameter and gradually expands as it rises owing to the 
decrease in air pressure. When the balloon reaches a diameter of 13 to 
22 ft (4 to 7 m), it bursts and a parachute is deployed to slow the 
descent of the associated radiosonde. Weather balloons would not be 
recovered.
    The deployment of weather balloons does not include the use of 
active acoustics and therefore, is not anticipated to have the 
potential for impacts on marine mammals or their habitat.
    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 2021-2022 IHA application summarize 
available information regarding status and trends, distribution and 
habitat preferences, and behavior and life history, of the potentially 
affected species. Additional information regarding population trends 
and threats may be found in NMFS's Stock Assessment Reports (SARs; 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about 
these species (e.g., physical and behavioral descriptions) may be found 
on NMFS's 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. For taxonomy, we follow Committee on 
Taxonomy (2021). 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's SARs). While no 
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's 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's 2020 Alaska SARs (Muto et al., 2021). All values presented in 
Table 3 are the most recent available at the time of publication and 
are available in the 2020 SARs (Muto et al., 2021) and available online 
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.

                                                 Table 3--Species Expected To Occur in the Project Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                         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--Cetacean--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Monodontidae:
    Beluga whale....................  Delphinapterus leucas..  Beaufort Sea \4\.......  -,-; N              39,258 (0.229, N/A,       \4\ UND        102
                                                                                                             1992).
    Beluga whale....................  Delphinapterus leucas..  Eastern Chukchi........  -,-; 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...............      5,100      6,459
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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.

[[Page 47073]]

 
\2\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\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.

    Activities conducted during this proposed action are expected to 
cause harassment, as defined by the MMPA as it applies to military 
readiness, to the beluga whale (Delphinapterus leucas; of the Beaufort 
and eastern Chukchi Sea stocks) and the ringed seal (Pusa hispida 
hispida). As indicated above in Table 3, both species (with three 
managed stocks) temporally and spatially co-occur with the activity to 
the degree that take is reasonably likely to occur, and we have 
proposed authorizing it. While bowhead whales (Balaena mysticetus), 
gray whales (Eschrichtius robustus), bearded seals (Erignathus 
barbatus), spotted seals (Phoca largha), and ribbon seals (Histiophoca 
fasciata) have been documented in the area, the temporal and spatial 
occurrence of these species is such that take is not expected to occur, 
and they are not discussed further beyond the explanation provided 
here.
    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 
(Carretta et al., 2017; 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 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.
    Ringed seals lack a reliable population estimate for the entire 
stock. Conn et al., (2014) calculated an abundance estimate of 171,418 
ringed seals (95 percent CI: 141,588-201,090) using a sub-sample of 
data collected from the U.S. portion of the Bering Sea in 2012. 
Researchers plan to combine these results with those from spring 
surveys of the Chukchi and Beaufort Seas once complete. During the 
summer months, ringed seals forage along ice edges or in open water 
areas of high productivity and have been observed in the northern 
Beaufort Sea during summer months (Harwood and Stirling, 1992; Freitas 
et al., 2008; Kelly et al., 2010a; Harwood et al., 2015). This open 
water movement becomes limited with the onset of ice in the fall 
forcing the seals to move west and south as ice packs advance, 
dispersing the animals throughout the Chukchi and Bering Seas, with 
only a portion remaining in the Beaufort Sea (Frost and Lowry, 1984; 
Crawford et al., 2012; Harwood et al., 2012). In a telemetry study, 
ringed seals tagged showed preference for Continental Shelf waters over 
96 percent of tracking days, where near-continuous foraging activities 
were noted (Von Duyke et al., 2020).
    The Navy has utilized Kelly et al., (2010a) in their IHA 
application to determine the abundance estimate for ringed seals, which 
is based on surveys conducted by Bengtson et al., (2005) and Frost et 
al., (2004) in the 1990s and 2000 (300,000 ringed seals). NMFS 2013 
Alaska SAR (Allen & Angliss, 2013) has noted that this value is likely 
an underestimate as it is based on surveys that are older than eight 
years and that make up a portion of the known range of the ringed seal. 
Conn et al., (2014) determined a different abundance estimate from 
Kelly et al., 2010a (171,418), which is noted in NMFS's 2020 Alaska SAR 
(Muto et al., 2021) to also be inaccurate 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., (2021) notes that an accurate population 
estimate is likely larger by a factor of two or more. However, no 
accepted population estimate is present for Arctic ringed seals. 
Therefore, in the interest in making conservative decisions, NMFS will 
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).
    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.
    There are two migration areas used by Beaufort Sea belugas that 
overlap the proposed project site. One, located in the Eastern Chukchi 
and Alaskan Beaufort Sea, is a migration area in use from April to May. 
The second, 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) there is some overlap in distribution with 
the eastern Chukchi Sea beluga whale stock.

[[Page 47074]]

    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. A whale tagged in the eastern Chukchi 
Sea in 2007 overwintered in the waters north of Saint Lawrence Island 
during 2007/2008 and moved to near King Island in April and May before 
moving north through the Bering Strait in late May and early June 
(Suydam, 2009).

Ringed Seal

    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., 2017).
    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 require snow 
depths of at least 20-26 in (50-65 cm) for functional birth lairs 
(Kelly, 1988b; Lydersen, 1998; Lydersen and Gjertz, 1986; Smith and 
Stirling, 1975). Such depths typically are found only where 8-12 in 
(20-30 cm) or more of snow has accumulated on flat ice and then drifted 
along pressure ridges or ice hummocks (Hammill, 2008; Lydersen et al., 
1990; Lydersen and Ryg, 1991; Smith and Lydersen, 1991). Ringed seals 
are born beginning in March, but the majority of births occur in early 
April. About a month after parturition, mating begins in late April and 
early May.
    In Alaskan waters, during winter and early spring when sea ice is 
at its maximum extent, ringed seals are abundant in the northern Bering 
Sea, Norton and Kotzebue Sounds, and throughout the Chukchi and 
Beaufort seas (Frost, 1985; Kelly, 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 nmi (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). With the onset of fall freeze, ringed seal movements become 
increasingly restricted and seals will either move west and south with 
the advancing ice pack with many seals dispersing throughout the 
Chukchi and Bering Seas, or remaining in the Beaufort Sea (Crawford et 
al., 2012; Frost and Lowry, 1984; Harwood et al., 2012). Kelly et al., 
(2010a) tracked home ranges for ringed seals in the subnivean period 
(using shore-fast ice); the size of the home ranges varied from less 
than 1 up to 279 km\2\ (median 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., 2010a). 
Near large polynyas, ringed seals maintain ranges, up to 7,000 km\2\ 
during winter and 2,100 km\2\ during spring (Born et al., 2004). Some 
adult ringed seals return to the same small home ranges they occupied 
during the previous winter (Kelly et al., 2010a). The size of winter 
home ranges can vary by up to a factor of 10 depending on the amount of 
fast ice; seal movements were more restricted during winters with 
extensive fast ice, and were much less restricted where fast ice did 
not form at high levels (Harwood et al., 2015).
    Most taxonomists recognize five subspecies of ringed seals. The 
Arctic ringed seal subspecies occurs in the Arctic Ocean and Bering Sea 
and is the only stock that occurs in U.S. waters (referred to as the 
Arctic stock). 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.

Ice Seal Unusual Mortality Event (UME)

    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 February 9, 2020, there have been 278 dead seals reported, with 
112 stranding in 2018, 165 in 2019, and one in 2020, which is nearly 
five times the average number of strandings 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 
the cause of the UME remains unknown.
    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

[[Page 47075]]

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. The 
investigation into the cause of the most recent UME is ongoing.
    As of July 2021, the current number of animals counted as part of 
the UME is 316. However, while no ice seals have stranded in 2021, at 
the time of this publication, the UME is still considered ongoing. More 
detailed information is available at: https://www.fisheries.noaa.gov/national/marine-life-distress/2018-2019-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. Current data indicate that 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) recommended that marine mammals be 
divided into functional hearing groups based on directly measured or 
estimated hearing ranges on the basis of available behavioral response 
data, audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. 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           150 Hz to 160 kHz.
 (dolphins, 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)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (sea 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. 
Two marine mammal species (one cetacean (odontocete species) and one 
pinniped (phocid species)) have the reasonable potential to co-occur 
with the proposed survey activities. Beluga whales are classified as 
mid-frequency odontocete cetaceans. Please refer back to Table 3.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and 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 are likely to 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 [micro]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 then taking the square 
root of the average (Urick, 1983). RMS accounts for both positive and 
negative values;

[[Page 47076]]

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).
    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 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

[[Page 47077]]

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).
    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.
    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.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale, harbor porpoise 
(Phocoeona phocoena), and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and three species of pinnipeds (northern elephant 
seal (Mirounga angustirostris), harbor seal (Phoca vitulina), and 
California sea lion (Zalophus californianus)) exposed to a limited 
number of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (Finneran, 2015). TTS was not observed in trained 
spotted and ringed seals exposed to impulsive noise at levels matching 
previous predictions of TTS onset (Reichmuth et al., 2016). In general, 
harbor seals and harbor porpoises have a lower TTS onset than other 
measured pinniped or cetacean species. Additionally, the existing 
marine mammal TTS data come from a limited number of individuals within 
these species. For example, there are no data available on noise-
induced hearing loss for mysticetes. For summaries of data on TTS in 
marine mammals or for further discussion of TTS onset thresholds, 
please see Southall et al., (2007), Finneran and Jenkins (2012), and 
Finneran (2015).
    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). 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). 
Please see Appendices B-C of Southall et al., (2007) for a review of 
studies involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 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).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2003). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely, and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al., 2004; Goldbogen et al., 2013). 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

[[Page 47078]]

presentation, as well as differences in species sensitivity, are likely 
contributing factors to differences in response in any given 
circumstance (e.g., Croll et al., 2001; Nowacek et al.; 2004; Madsen et 
al., 2006; Yazvenko et al., 2007). A determination of whether foraging 
disruptions incur fitness consequences would require information on or 
estimates of the energetic requirements of the affected individuals and 
the relationship between prey availability, foraging effort and 
success, and the life history stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et 
al., 2007).
    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). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Morton and Symonds, 2002; 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).
    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). However, it should be noted that response to 
a perceived predator does not necessarily invoke flight (Ford and 
Reeves, 2008), and whether individuals are solitary or in groups may 
influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been observed in marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (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). However, 
Ridgway et al., (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than 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.
    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 (labeled from 1 to 3), effects that could affect 
vital rates (labeled 4 to 6), to effects that were thought likely to 
influence vital rates (labeled 7 to 9). 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). Additional 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

[[Page 47079]]

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).
    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). Although a minor change to a behavior may 
occur as a result of exposure to the sources in the proposed action, 
these changes would be within the normal range of behaviors for the 
animal (e.g., the use of a breathing hole further from the source, 
rather than one closer to the source, would be within the normal range 
of behavior) (Kelly et al., 1988d).
    Some behavioral response studies have been conducted on odontocete 
responses to sonar. In studies that examined sperm whales (Physeter 
macrocephalus) and false killer whales (Pseudorca crassidens) (both in 
the mid-frequency cetacean hearing group), the marine mammals showed 
temporary cessation of calling and avoidance of sonar sources (Akamatsu 
et al., 1993; Watkins and Schevill, 1975). Sperm whales resumed calling 
and communication approximately two minutes after the pings stopped 
(Watkins and Schevill, 1975). False killer whales moved away from the 
sound source but returned to the area between 0 and 10 minutes after 
the end of transmissions (Akamatsu et al., 1993). 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, if significant behavioral responses occur they would likely be 
short term. In fact, no significant behavioral responses such as panic, 
stranding, or other severe reactions have been observed during 
monitoring of actual training exercises (Department of the Navy 2011, 
2014; Smultea and Mobley, 2009; Watwood et al., 2012).
    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. Although icebreaking will not be occurring during this 
proposed action, 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). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response.

[[Page 47080]]

During a stress response, an animal uses glycogen stores that can be 
quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments 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 altering critical behaviors. It is 
important to distinguish TTS and PTS, which persist after the sound 
exposure, from masking, which occurs during the sound exposure. Because 
masking (without resulting in TS) is not associated with abnormal 
physiological function, it is not considered a physiological effect, 
but rather a potential behavioral effect.
    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.
    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 47081]]

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. There will be no permanent loss or 
modification of physical ice habitat used by ringed seals. Vessel 
movement would have no effect on physical beluga habitat as beluga 
habitat is solely within the water column. Furthermore, any testing of 
towed sources would be limited in duration and the deployed sources 
that would remain in use after the vessels have left the survey area 
have low duty cycles and lower source levels. There would not be an 
expected habitat-related effects from acoustic sources that could 
impact the in-water habitat of ringed seals or beluga whale foraging 
habitat.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through the IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    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 for individual marine mammals 
resulting from exposure to acoustic transmissions. No Level A 
harassment is estimated to occur. Therefore, Level A harassment is 
neither anticipated nor proposed to be authorized.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    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) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of 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 estimate.

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 for non-explosive sources--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 (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (e.g., hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor 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 typical generalized 
acoustic thresholds are received levels of 120 dB re 1 [mu]Pa (rms) for 
continuous (e.g., vibratory pile-driving, drilling) and above 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 these dose response functions.
    The Navy's dose response functions were developed to estimate take 
from sonar and similar transducers. 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 new 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 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 [micro]Pa to a maximum of 198-214 re 1 [micro]Pa 
at 1 m. Sonar signals were ramped up

[[Page 47082]]

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 [micro]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 [micro]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 to be unlikely.
    Level A harassment for non-explosive sources--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 activities involve only 
non-impulsive sources.
    These thresholds are provided in Table 5 below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS 2018 Technical Guidance, which may be accessed at 
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.

                     Table 5--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                     PTS onset acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1 [mu]Pa2s. In this Table, thresholds are abbreviated to reflect American National
  Standards Institute standards (ANSI, 2013). However, peak sound pressure is defined by ANSI as incorporating
  frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
  being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
  hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
  designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
  that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
  exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
  is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Quantitative Modeling

    The Navy performed a quantitative analysis to estimate the number 
of marine mammals that could 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 Navy Marine Species 
Density Database, marine mammal depth occurrence distributions (U.S. 
Department of the Navy, 2017b), oceanographic and environmental data, 
marine 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 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

[[Page 47083]]

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.
    Because of 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.
    For the other 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.
    Table 6 provides range to effects for noise produced through use of 
the proposed sources to mid-frequency cetacean and pinniped-specific 
criteria. Range to effects is important information in predicting non-
impulsive acoustic impacts. Therefore, the ranges in Table 6 provide 
realistic maximum distances over which the specific effects from the 
use of non-impulsive sources during the proposed action would be 
possible.

           Table 6--Range to PTS, TTS, and Behavioral Effects in the Project Area Based on Cutoff Distances for Non-Impulsive Acoustic Sources
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            Range to behavioral effects   Range to TTS effects  (meters)  Range to PTS effects  (meters)
                                                                     (meters)                           \c\                             \c\
                       Source type                       -----------------------------------------------------------------------------------------------
                                                            MF cetacean      pinniped       MF cetacean      pinniped       MF cetacean      pinniped
--------------------------------------------------------------------------------------------------------------------------------------------------------
On-site drifting sources \b\............................      \a\ 10,000      \a\ 10,000               0               0               0               0
Fixed sources...........................................      \a\ 20,000       \a\ 5,000               0               0               0               0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Cutoff distance applied (U.S. Department of the Navy, 2017a).
\b\ Assessed under the assumption that some of the on-site drifting sources would become closer together.
\c\ No effect (and therefore, no distance from source) is anticipated based on the NAEMO modeling.

    A behavioral response study conducted on and around the Navy range 
in Southern California (SOCAL BRS) observed reactions to sonar and 
similar sound sources by several marine mammal species, including 
Risso's dolphins (Grampus griseus), a mid-frequency cetacean (DeRuiter 
et al., 2013; Goldbogen et al., 2013; Southall et al., 2011; Southall 
et al., 2012; Southall et al., 2013). In a preliminary analysis, none 
of the Risso's dolphins exposed to simulated or real mid-frequency 
sonar demonstrated any overt or obvious responses (Southall et al., 
2012, Southall et al., 2013). In general, although the responses to the 
simulated sonar were varied across individuals and species, none of the 
animals exposed to real Navy sonar responded; these exposures occurred 
at distances beyond 10 km, and were up to 100 km away (DeRuiter et al., 
2013). These data suggest that most odontocetes (not including beaked 
whales (Family Ziphiidae) and harbor porpoises) likely do not exhibit 
significant behavioral reactions to sonar and other transducers beyond 
approximately 10 km. Therefore, the Navy uses a cutoff distance for 
odontocetes of 10 km for moderate source level, single platform 
training, and testing events, and 20 km for all other events, including 
this proposed action (U.S. Department of the Navy, 2017a). NMFS 
proposes to adopt this approach in support of this proposed IHA.
    Southall et al., (2007) reported that pinnipeds do not exhibit 
strong reactions to SPLs up to 140 dB re 1 [micro]Pa from non-impulsive 
sources. While there are limited data on pinniped behavioral responses 
beyond about 3 km in the water, the Navy used a distance cutoff of 2.7 
nm (5 km) for moderate source level, single platform training and 
testing events, and 5.4 nm (10 km) for all other events, including the 
proposed Arctic Research Activities (U.S. Department of the Navy, 
2017a).

[[Page 47084]]

NMFS proposes to adopt this approach in support of this proposed IHA.
    Regardless of the received level at the cutoff distances described 
above, take is not estimated to occur beyond 10 and 20 km from the 
source for pinnipeds and cetaceans, respectively. No instances of PTS 
were modeled for any species or stock; as such, no take by Level A 
harassment is anticipated or proposed to be authorized. Further 
information on cutoff distances can be found in Section 6.5.1 in ONR's 
2021-2022 IHA application on NMFS' website: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.
    The marine mammal density numbers utilized for quantitative 
modeling are from the Navy Marine Species Density Database (U.S. 
Department of the Navy, 2014). Density estimates are based on habitat-
based modeling by Kaschner et al., (2006) and Kaschner (2004). While 
density estimates for the two stocks of beluga whales are equal 
(Kaschner et al., 2006; Kaschner 2004), take has been apportioned to 
each stock proportional to the abundance of each stock. Table 7 shows 
the exposures expected for the beluga whale and ringed seal based on 
NAEMO modeled results.

                          Table 7--Quantitative Modeling Results of Potential Exposures
----------------------------------------------------------------------------------------------------------------
                                      Density         Level B         Level B                     Percentage  of
             Species                 (animals/      harassment      harassment    Total proposed    stock taken
                                      km\2\)       (behavioral)        (TTS)            take            \1\
----------------------------------------------------------------------------------------------------------------
                                              Cetacean (odontocete)
----------------------------------------------------------------------------------------------------------------
Beluga Whale (Beaufort Sea                0.0087             375               0             375            0.96
 stock) \1\.....................
Beluga Whale (Chukchi Sea stock)                             125               0             125            0.94
 \1\............................
----------------------------------------------------------------------------------------------------------------
                                                Pinniped (phocid)
----------------------------------------------------------------------------------------------------------------
Ringed Seal.....................          0.3958           6,050               0           6,050            3.53
----------------------------------------------------------------------------------------------------------------
\1\ Acoustic exposures to beluga whales were not modeled at the stock level. Take of beluga whales in each stock
  was based on the proportion of each stock in relation to the total number of beluga whales. Therefore, 75
  percent of the calculated take was apportioned to the Beaufort Sea stock, and 25 percent of the calculated
  take was apportioned to the Eastern Chukchi Sea stock.

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, we 
carefully consider 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

    Ships operated by or for the Navy have personnel assigned to stand 
watch at all times, day and night, when moving through the water. While 
in transit, ships must use extreme caution and proceed at a safe speed 
(1-3 knots in ice; <10 knots in open ice-free waters) such that the 
ship can take proper and effective action to avoid a collision with any 
marine mammal and can be stopped within a distance appropriate to the 
prevailing circumstances and conditions.
    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.
    During mooring or UUV deployment, visual observation would start 15 
minutes prior to and continue throughout the deployment within an 
exclusion 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 an exclusion zone of 500 yards (yd; 457 m) around 
observed whales, and 200 ft (183 m) around all other marine mammals, 
provided it is safe to do so in ice-free waters.
    All personnel conducting on-ice experiments, as well as all 
aircraft operating in the study area, are required

[[Page 47085]]

to maintain a separation distance of 1,000 ft (305 m) from any observed 
marine mammal.
    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, vessel, or aircraft, 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 whale 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 whale in order to maintain an exclusion zone of 500 yd 
(457 m).
    Based on our evaluation of the Navy's proposed measures, NMFS has 
preliminarily determined that the proposed mitigation measures provide 
the means 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 in the 
proposed action area. Effective reporting is critical, both to 
compliance as well as to ensure 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).
     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 undertake extensive 
training in accordance with the U.S. Navy Lookout Training Handbook or 
civilian equivalent, including on the job instruction and a formal 
Personal Qualification Standard program (or equivalent program for 
supporting contractors or civilians), to certify that they have 
demonstrated all necessary skills (such as detection and reporting of 
floating or partially submerged objects). Additionally, watch personnel 
have taken 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 
Lookout Training Handbook 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.
    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) (U.S. 
Department of the Navy, 2011). The ICMP has been developed in direct 
response to Navy permitting requirements established through various 
environmental compliance efforts. As a framework document, the ICMP 
applies by regulation to those activities on ranges and operating areas 
for which the Navy is seeking or has sought incidental take 
authorizations. The ICMP is intended to coordinate monitoring efforts 
across all regions and to allocate the most appropriate level and type 
of effort based on a set of standardized research goals, and in 
acknowledgement of regional scientific value and resource availability.
    The ICMP is focused on Navy training and testing ranges where the 
majority of Navy activities occur regularly as those areas have the 
greatest potential for being impacted. ONR's Arctic Research Activities 
in comparison is a less intensive test with little human activity 
present in the Arctic. Human presence is limited to a minimal amount of 
days for source operations and source deployments, in contrast to the 
large majority (greater than 95 percent) of time that the sources will 
be left behind and operate autonomously. Therefore, a dedicated 
monitoring project is not warranted. However, ONR will record all 
observations of marine mammals, including the marine mammal's location 
(latitude and longitude), behavior, and distance from project 
activities.
    The Navy is committed to documenting and reporting relevant aspects 
of research and testing activities to verify implementation of 
mitigation, comply with permits, and improve future environmental 
assessments. If any injury or death of a marine mammal is observed 
during the 2021-2022 Arctic Research Activities, 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, during on-
ice experiments, or by transiting vessel).
    ONR will provide NMFS with a draft exercise monitoring report 
within 90 days of the conclusion of the proposed activity. The draft 
exercise monitoring report will include data regarding acoustic source 
use and any mammal

[[Page 47086]]

sightings or detection will be 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 responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), 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's 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 environmental 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).
    Underwater acoustic transmissions associated with the Arctic 
Research Activities, 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 individuals that are taken by Level B harassment could 
include alteration of dive behavior, alteration of 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. Most likely, individuals will simply be temporarily 
displaced by moving away from the acoustic source. As described 
previously in the behavioral effects section, 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). Although 
a minor change to a behavior may occur as a result of exposure to the 
sound sources associated with the proposed action, these changes would 
be within the normal range of behaviors for the animal (e.g., the use 
of a breathing hole further from the source, rather than one closer to 
the source, would be within the normal range of behavior). Thus, even 
repeated Level B harassment of some small subset of the overall stock 
is unlikely to result in any significant realized decrease in fitness 
for the affected individuals, and would not result in any adverse 
impact to the stock as a whole.
    The project is not expected to have significant 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 cause significant or long-term negative consequences.
    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 the species or stock 
through effects on annual rates of recruitment or survival:
     No injury, serious injury, or mortality is anticipated or 
authorized;
     Impacts would be limited to Level B harassment only;
     TTS is not expected or predicted to occur; only temporary 
behavioral modifications are expected to result from these proposed 
activities; and
     There will be no permanent or significant loss or 
modification of marine mammal prey or habitat.
    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. However, the permitted sources would be placed 
outside of the range for subsistence hunting and ONR has been 
communicating with the Native communities about the proposed action. 
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 and outside of known 
subsistence use areas. However, almost all leave-behind sources that 
would constitute most of the Level B take would be approximately 240 mi 
(386 km) from shore. In comparison with IHAs issued to ONR for their 
previous Arctic Research Activities, this project is further north; 
therefore, there is no spatial overlap between known

[[Page 47087]]

subsistence harvest sites and the proposed activities contained herein. 
Furthermore, and as stated above, the range to effects for non-
impulsive acoustic sources in this experiment is much smaller than the 
distance from shore, with acoustic sources that could constitute take 
being located far away from known subsistence hunting areas. Lastly, 
the proposed action would not remove individuals from the population.
    Based on the description of the specified activity, 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.

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 the NMFS Alaska 
Regional Office (AKR).
    NMFS is proposing to authorize take of ringed seals, which are 
listed under the ESA. The Office of Protected Resources has requested 
initiation of Section 7 consultation with 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 fourth year of Arctic Research 
Activities in the Beaufort and eastern Chukchi Seas from October 2021-
October 2022, provided the previously mentioned mitigation, monitoring, 
and reporting requirements are incorporated. A draft of the proposed 
IHA can be found at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed fourth 
year of Arctic Research Activities. We also request at this time 
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 proposed 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, 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); 
and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    Upon review of the request for renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS determines 
that there are no more than minor changes in the activities, the 
mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: August 18, 2021.
Angela Somma,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-18070 Filed 8-20-21; 8:45 am]
BILLING CODE 3510-22-P