[Federal Register Volume 89, Number 157 (Wednesday, August 14, 2024)]
[Notices]
[Pages 66068-66091]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-18130]
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DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric Administration
[RTID 0648-XE173]
Takes of Marine Mammals Incidental to Specified Activities;
Taking Marine Mammals Incidental to the Office of Naval Research's
Arctic Research Activities in the Beaufort and Chukchi Seas (Year 7)
AGENCY: National Marine Fisheries Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA), Commerce.
ACTION: Notice; proposed incidental harassment authorization; request
for comments on proposed authorization and possible renewal.
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SUMMARY: NMFS has received a request from the Office of Naval Research
(ONR) for authorization to take marine mammals incidental to Arctic
Research Activities (ARA) in the Beaufort Sea and eastern Chukchi Sea.
Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is requesting
comments on its proposal to issue an incidental harassment
authorization (IHA) to incidentally take marine mammals during the
specified activities. NMFS is also requesting comments on a possible
one-time, 1-year renewal that could be issued under certain
circumstances and if all requirements are met, as described in Request
for Public Comments at the end of this notice. NMFS will consider
public comments prior to making any final decision on the issuance of
the requested MMPA authorization and agency responses will be
summarized in the final notice of our decision. The ONR's activities
are considered military readiness activities pursuant to the MMPA, as
amended by the National Defense Authorization Act for Fiscal Year 2004
(2004 NDAA).
DATES: Comments and information must be received no later than
September 13, 2024.
ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,
Permits and Conservation Division, Office of Protected Resources,
National Marine Fisheries Service and should be submitted via email to
[email protected]. Electronic copies of the application and
supporting documents, as well as a list of the references cited in this
document, may be obtained online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities. In case of problems accessing these
documents, please call the contact listed below.
Instructions: NMFS is not responsible for comments sent by any
other method, to any other address or individual, or received after the
end of the comment period. Comments, including all attachments, must
not exceed a 25-megabyte file size. All comments received are a part of
the public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying
information (e.g., name, address) voluntarily submitted by the
commenter may be publicly accessible. Do not submit confidential
business information or otherwise sensitive or protected information.
FOR FURTHER INFORMATION CONTACT: Alyssa Clevenstine, Office of
Protected Resources, NMFS, (301) 427-8401.
SUPPLEMENTARY INFORMATION:
[[Page 66069]]
Background
The MMPA prohibits the ``take'' of marine mammals, with certain
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361
et seq.) direct the Secretary of Commerce (as delegated to NMFS) to
allow, upon request, the incidental, but not intentional, taking of
small numbers of marine mammals by U.S. citizens who engage in a
specified activity (other than commercial fishing) within a specified
geographical region if certain findings are made and either regulations
are proposed or, if the taking is limited to harassment, a notice of a
proposed IHA is provided to the public for review.
Authorization for incidental takings shall be granted if NMFS finds
that the taking will have a negligible impact on the species or
stock(s) and will not have an unmitigable adverse impact on the
availability of the species or stock(s) for taking for subsistence uses
(where relevant). Further, NMFS must prescribe the permissible methods
of taking and other ``means of effecting the least practicable adverse
impact'' on the affected species or stocks and their habitat, paying
particular attention to rookeries, mating grounds, and areas of similar
significance, and on the availability of the species or stocks for
taking for certain subsistence uses (referred to in shorthand as
``mitigation''); and requirements pertaining to the monitoring and
reporting of the takings. The definitions of all applicable MMPA
statutory terms cited above are included in the relevant sections
below.
The 2004 NDAA (Pub. L. 108-136) removed the ``small numbers'' and
``specified geographical region'' limitations indicated above and
amended the definition of ``harassment'' as applied to a ``military
readiness activity.'' The activity for which incidental take of marine
mammals is being requested qualifies as a military readiness activity.
National Environmental Policy Act
To comply with the National Environmental Policy Act of 1969 (NEPA;
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A,
NMFS must review our proposed action (i.e., the issuance of an IHA)
with respect to potential impacts on the human environment.
In 2018, the U.S. Navy prepared an Overseas Environmental
Assessment (OEA) analyzing the project. Prior to issuing the IHA for
the first year of this project, NMFS reviewed the 2018 EA and the
public comments received, determined that a separate NEPA analysis was
not necessary, and subsequently adopted the document and issued a NMFS
Finding of No Significant Impact (FONSI) in support of the issuance of
an IHA (83 FR 48799, September 27, 2018).
In 2019, the Navy prepared a supplemental OEA. Prior to issuing the
IHA in 2019, NMFS reviewed the supplemental OEA and the public comments
received, determined that a separate NEPA analysis was not necessary,
and subsequently adopted the document and issued a NMFS FONSI in
support of the issuance of an IHA (84 FR 50007, September 24, 2019).
In 2020, the Navy submitted a request for a renewal of the 2019
IHA. Prior to issuing the renewal IHA, NMFS reviewed ONR's application
and determined that the proposed action was identical to that
considered in the previous IHA. Because no significantly new
circumstances or information relevant to any environmental concerns had
been identified, NMFS determined that the preparation of a new or
supplemental NEPA document was not necessary and relied on the
supplemental OEA and FONSI from 2019 when issuing the renewal IHA in
2020 (85 FR 41560, July 10, 2020).
In 2021, the Navy submitted a request for an IHA for incidental
take of marine mammals during continuation of ARA. NMFS reviewed the
Navy's OEA and determined it to be sufficient for taking into
consideration the direct, indirect, and cumulative effects to the human
environment resulting from continuation of the ARA. NMFS subsequently
adopted that OEA and signed a FONSI (86 FR 54931, October 5, 2021).
In 2022, the Navy submitted a request for an IHA for incidental
take of marine mammals during continuation of ARA and prepared an OEA
analyzing the project. Prior to issuing the IHA for the project, we
reviewed the 2022-2025 OEA and the public comments received, determined
that a separate NEPA analysis was not necessary, and subsequently
adopted the document and issued our own FONSI in support of the
issuance of an IHA (87 FR 57458, September 20, 2022).
In 2023, the ONR requested a renewal of the 2022 IHA for ongoing
ARA from September 2023 to September 2024, and the 2022 IHA monitoring
report. Prior to issuing the renewal IHA, NMFS reviewed ONR's
application and determined that the proposed action was identical to
that considered in the previous IHA. Because no significantly new
circumstances or information relevant to any environmental concerns
were identified, NMFS determined that the preparation of a new or
supplemental NEPA document was not necessary and relied on the
supplemental OEA and FONSI from 2022 when issuing the renewal IHA in
2023 (88 FR 65657, September 18, 2023).
Accordingly, NMFS preliminarily has determined to adopt the Navy's
OEA for ONR ARA in the Beaufort and Chukchi Seas 2022-2025, provided
our independent evaluation of the document finds that it includes
adequate information analyzing the effects on the human environment of
issuing the IHA. NMFS is a not cooperating agency on the U.S. Navy's
OEA.
We will review all comments submitted in response to this notice
prior to concluding our NEPA process or making a final decision on the
IHA request.
Summary of Request
On March 29, 2024, NMFS received a request from the ONR for an IHA
to take marine mammals incidental to ARA in the Beaufort and Chukchi
Seas. Following NMFS' review of the application, the ONR submitted a
revised version on July 23, 2024. The application was deemed adequate
and complete on August 5, 2024. The ONR's request is for take of beluga
whales and ringed seals by Level B harassment only. Neither the ONR nor
NMFS expect serious injury or mortality to result from this activity
and, therefore, an IHA is appropriate.
This proposed IHA would cover the seventh year of a larger project
for which ONR obtained prior IHAs and renewal IHAs (83 FR 48799,
September 27, 2018; 84 FR 50007, September 24, 2019; 85 FR 53333,
August 28, 2020; 86 FR 54931, October 5, 2021; 87 FR 57458, September
20, 2022; 88 FR 65657, September 18, 2023). ONR has complied with all
the requirements (e.g., mitigation, monitoring, and reporting) of the
previous IHAs.
Description of Proposed Activity
Overview
The ONR proposes to conduct scientific experiments in support of
ARA using active acoustic sources within the Beaufort and Chukchi Seas.
Project activities involve acoustic testing and a multi-frequency
navigation system concept test using left-behind active acoustic
sources. The proposed experiments involve the deployment of moored,
drifting, and ice-tethered active acoustic sources from the Research
Vessel (R/V) Sikuliaq. Recovery of equipment may be from R/V Sikuliaq,
[[Page 66070]]
U.S. Coast Guard Cutter (CGC) HEALY, or another vessel, and icebreaking
may be required. Underwater sound from the active acoustic sources and
noise from icebreaking may result in Level B harassment of marine
mammals.
Dates and Duration
The proposed action would occur from September 2024 through
September 2025 and include up to two research cruises. Acoustic testing
would take place during the cruises, with the first cruise beginning
September 2, 2024, and a potential second cruise occurring in summer or
fall 2025, which may include up to 8 days of icebreaking activities.
Geographic Region
The proposed action would occur across the U.S. Exclusive Economic
Zone (EEZ) in the Beaufort and Chukchi Seas, partially in the high seas
north of Alaska, the Global Commons, and within a part of the Canadian
EEZ (in which the appropriate permits would be obtained by the Navy)
(figure 1). The proposed action would primarily occur in the Beaufort
Sea but the analysis considers the drifting of active sources on buoys
into the eastern portion of the Chukchi Sea. The closest point of the
study area to the Alaska coast is 204 kilometers (km; 110 nautical
miles (nm)). The proposed study area is approximately 639,267 square
kilometers (km\2\).
[[Page 66071]]
[GRAPHIC] [TIFF OMITTED] TN14AU24.000
Detailed Description of the Specified Activity
The ONR ARA Global Prediction Program supports two major projects:
Stratified Ocean Dynamics of the Arctic (SODA) and Arctic Mobile
Observing System (AMOS). The SODA and AMOS projects have been
previously discussed in association with previously issued IHAs (83 FR
40234, August 14, 2018; 84 FR 37240, July 31, 2019). However, only
activities relating to the AMOS project will occur during the period
covered by this proposed action.
The proposed action constitutes the development of a modified
system under the ONR AMOS involving very-low-, low-, and mid-frequency
(VLF, LF, MF) transmissions (35 Hertz (Hz), 900 Hz, and 10 kilohertz
(kHz), respectively). The AMOS project utilizes acoustic sources and
receivers to provide a means of performing under-ice navigation for
gliders and unmanned undersea vehicles (UUVs). This would allow for the
possibility of year-round scientific observations of the environment in
the Arctic. As an environment that is particularly affected by climate
change, year-round observations under a variety of ice conditions are
required to study the
[[Page 66072]]
effects of this changing environment for military readiness, as well as
the implications of environmental change to humans and animals. VLF
technology is important in extending the range of navigation systems
and has the potential to allow for development and use of navigational
systems that would not be heard by some marine mammal species and,
therefore, would be less impactful overall.
Up to six moorings (four fixed acoustic navigation sources
transmitting at 900 Hz, two fixed VLF sources transmitting at 35 Hz)
and two drifting ice gateway buoys (IGBs) would be configured with
active acoustic sources and would operate for a period of up to 1 year.
Four gliders with passive acoustics would be used to support drifting
IGBs. No UUV use is planned during the September 2024 research cruise;
however, there is the potential for one UUV (without active acoustic
sources) to be deployed and up to 8 days of icebreaking activities to
occur on a potential research cruise in summer/fall 2025, which would
require the use of a vessel with ice-breaking capabilities (e.g., CGC
HEALY).
During the research cruise, acoustic sources would be deployed from
the vessel for intermittent testing of the system components, which
would take place in the vicinity of the source locations (figure 1).
During this testing, 35 Hz, 900 Hz, 10 kHz, and acoustic modems would
be employed. The six fixed moorings would be anchored on the seabed and
held in the water column with subsurface buoys.
Autonomous vehicles would be able to navigate by receiving acoustic
signals from multiple locations and triangulating. This is needed for
vehicles that are under ice and cannot communicate with satellites.
Source transmits would be offset by 15 minutes from each other (i.e.,
sources would not be transmitting at the same time). All navigation
sources would be recovered. The purpose of the navigation sources is to
orient UUVs and gliders in situations when they are under ice and
cannot communicate with satellites.
The proposed action would utilize non-impulsive acoustic sources,
although not all sources will cause take of marine mammals (tables 1,
2). Marine mammal takes would arise from the operation of non-impulsive
active sources. Although not currently planned, icebreaking could occur
as part of this proposed action if a research vessel needs to return to
the study area before the end of the IHA period to ensure scientific
objectives are met. In this case, icebreaking could result in Level B
harassment.
Below are descriptions of the platforms and equipment that would be
deployed at different times during the proposed activity.
Research Vessels
The R/V Sikuliaq would perform the research cruise in September
2024 and conduct testing of acoustic sources during the cruise, as well
as leave sources behind to operate as a year-round navigation system
observation. The vessel to be used in a potential 2025 cruise is yet to
be determined but the most probable option would be the CGC HEALY.
The R/V Sikuliaq has a maximum speed of approximately 12 knots
(22.2 km per hour (km/hr)) with a cruising speed of 11 knots (20.4 km/
hr). The R/V Sikuliaq is not an icebreaking ship but an ice
strengthened ship. It would not be icebreaking and therefore acoustic
signatures of icebreaking for the R/V Sikuliaq are not relevant. CGC
HEALY travels at a maximum speed of 17 knots (31.5 km/hr) with a
cruising speed of 12 knots (22.2 km/hr) and a maximum speed of 3 knots
(5.6 km/hr) when traveling through 1.07 m (3.5 ft) of sea ice. While no
icebreaking cruise on the CGC HEALY is scheduled during the IHA period,
need may arise. Therefore, for the purposes of this IHA application, an
icebreaking cruise is considered.
The R/V Sikuliaq, CGC HEALY, or any other vessel operating a
research cruise associated with the Proposed Action may perform the
following activities during their research cruises:
Deployment of moored and/or ice-tethered passive sensors
(oceanographic measurement devices, acoustic receivers);
Deployment of moored and/or ice-tethered active acoustic
sources to transmit acoustic signals;
Deployment of UUVs;
Deployment of drifting buoys, with or without acoustic
sources; or,
Recovery of equipment.
Glider Surveys
Glider surveys are proposed for the research cruise. All gliders
would be recovered; some may be recovered during the cruise, but the
remainder would be recovered at a later date. Up to four gliders would
be deployed during the research cruise as part of on-ice operations
(one to two gliders would be associated with each on-ice station).
Long-endurance, autonomous sea gliders are intended for use in
extended missions in ice-covered waters. Gliders are buoyancy-driven,
equipped with satellite modems providing two-way communication, and are
capable of transiting to depths of up to 1,000 m (3,280 ft). Gliders
would collect data in the area of the shallow water sources and moored
sources, moving at a speed of 0.25 meters per second (m/s; 23
kilometers per day (km/day)). A combination of recent advances in sea
glider technology would provide full-year endurance. When operating in
ice-covered waters, gliders navigate by trilateration (the process of
determining location by measurement of distances, using the geometry of
circles, spheres or triangles) from moored acoustic sound sources (or
dead reckoning should navigation signals be unavailable); they do not
contain any active acoustic sources. Hibernating gliders would continue
to track their position, waking to reposition should they drift too far
from their target region. Gliders would measure temperature, salinity,
dissolved oxygen, rates of dissipation of temperature variance (and
vertical turbulent diffusivity), and multi-spectral down welling
irradiance.
Moored and Drifting Acoustic Sources
During the September 2024 cruise, active acoustic sources would be
lowered from the cruise vessel while stationary, deployed on gliders
and UUVs, or deployed on fixed AMOS and VLF moorings for intermittent
testing of the system components. The testing would take place in the
vicinity of the source locations in figure 1. During this testing, 35
Hz, 900 Hz, 10 kHz, and acoustic modems would be employed. No UUV use
is planned during the September 2024 research cruise but UUV use may be
included in future test plans covered by this IHA.
Up to four fixed acoustic navigation sources transmitting at 900 Hz
would remain in place for a year. These moorings would be anchored on
the seabed and held in the water column with subsurface buoys. All
sources would be deployed by shipboard winches, which would lower
sources and receivers in a controlled manner. Anchors would be steel
``wagon wheels'' typically used for this type of deployment. Two VLF
sources transmitting at 35 Hz would be deployed in a similar manner.
Two drifting IGBs would also be configured with active acoustic
sources.
[[Page 66073]]
Table 1--Characteristics of Modeled Acoustic Sources
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Signal strength (dB Pulse width/duty
Platform (total number deployed) Acoustic source Purpose/ function Frequency re 1 [mu]Pa at 1 m) cycle
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REMUS 600 UUV \a\ (up to 1)........ WHOI Micro-modem...... Acoustic 900-950 Hz............ NTE 180 dB by sys 5 pings/hour with 30
communications. design limits. sec pulse length.
REMUS 600 UUV \a\ (up to 1)........ UUV/WHOI Micro-modem.. Acoustic 8-14 kHz.............. NTE 185 dB by sys 10% average duty
communications. design limits. cycle, with 4 sec
pulse length.
IGB (drifting) (2)................. WHOI Micro-modem...... Acoustic 900-950 Hz............ NTE 180 dB by sys Transmit every 4
communications. design limits. hours, 30 sec pulse
length.
IGB (drifting) (2)................. WHOI Micro-modem...... Acoustic 8-14 kHz.............. NTE 185 dB by sys Typically receive
communications. design limits. only. Transmit is
very intermittent.
Mooring (6)........................ WHOI Micro-modem (4).. Acoustic Navigation.. 900-950 Hz............ NTE 180 dB by sys Transmit every 4
design limits. hours, 30 sec pulse
length.
Mooring (6)........................ VLF (2)............... Acoustic Navigation.. 35 Hz................. NTE 190 dB........... Up to 4 times per
day, 10 minutes
each.
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Note: dB re 1 [mu]Pa at 1 m = decibels referenced to 1 microPascal at 1 meter; Hz = Hertz; IGB = Ice Gateway Buoy; kHz = kilohertz; NTE = not to exceed;
VLF = very low frequency; WHOI = Woods Hole Oceanographic Institution.
\a\ REMUS use is not anticipated during the September 2024 cruise but is included in case of future use during the proposed IHA period.
Activities Not Likely To Result in Take
The following activities have been determined to be unlikely to
result in take of marine mammals. These activities are described here
but they are not discussed further in this notice.
De minimis Sources--The ONR characterizes de minimis sources as
those with the following parameters: low source levels (SLs), narrow
beams, downward directed transmission, short pulse lengths, frequencies
outside known marine mammal hearing ranges, or some combination of
these factors (Navy, 2013). NMFS concurs with the ONR's determination
that the sources they have identified here as de minimis are unlikely
to result in take of marine mammals. The following are some of the
planned de minimis sources which would be used during the proposed
action: Woods Hole Oceanographic Institution (WHOI) micromodem,
Acoustic Doppler Current Profilers (ADCPs), ice profilers, and
additional sources below 160 decibels referenced to 1 microPascal (dB
re 1 [mu]Pa) used during towing operations. ADCPs may be used on
moorings. Ice-profilers measure ice properties and roughness. The ADCPs
and ice-profilers would all be above 200 kHz and therefore out of
marine mammal hearing ranges, with the exception of the 75 kHz ADCP
which has the characteristics and de minimis justification listed in
table 2. They may be employed on moorings or UUVs.
A WHOI micromodem will also be employed during the leave behind
period. In contrast with the WHOI micromodem usage described in table
1, which covers the use of the micromodem during research cruises, the
use of the source during the leave behind period differs in nature.
During this period, it is being used for very intermittent
communication with vehicles to communicate vehicle status for safety of
navigation purposes, and is treated as de minimis while employed in
this manner.
Table 2--Parameters for De Minimis Non-Impulsive Acoustic Sources
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Sound pressure
Source name Frequency level (dB re 1 Pulse length Duty cycle De minimis
range (kHz) [mu]Pa at 1 m) (seconds) (percent) justification
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ADCP.......................... >200, 150, or 190 <0.001 <0.1 Very low pulse
75 length, narrow
beam, moderate
source level.
Nortek Signature 500 kHz 500 214 <0.1 <13 Very high
Doppler Velocity Log. frequency.
CTD Attached Echosounder...... 5-20 160 0.004 2 Very low source
level.
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Note: dB re 1 [mu]Pa at 1 m = decibels referenced to 1 microPascal at 1 meter; kHz = kilohertz; ADCP = acoustic
Doppler current profiler; CTD = conductivity temperature depth.
Drifting Oceanographic Sensors--Observations of ocean-ice
interactions require the use of sensors that are moored and embedded in
the ice. For the proposed action, it will not be required to break ice
to do this, as deployments can be performed in areas of low ice-
coverage or free floating ice. Sensors are deployed within a few dozen
meters of each other on the same ice floe. Three types of sensors would
be used: autonomous ocean flux buoys, Integrated Autonomous Drifters,
and ice-tethered profilers. The autonomous ocean flux buoys measure
oceanographic properties just below the ocean-ice interface. The
autonomous ocean flux buoys would have ADCPs and temperature chains
attached, to measure temperature, salinity, and other ocean parameters
the top 6 m (20 ft) of the water column. Integrated Autonomous Drifters
would have a long temperate string extending down to 200 m (656 ft)
depth and would incorporate meteorological sensors, and a temperature
spring to estimate ice thickness. The ice-tethered profilers would
collect information on ocean temperature, salinity, and velocity down
to 250 m (820 ft) depth.
Up to 20 Argo-type autonomous profiling floats may be deployed in
the central Beaufort Sea. Argo float drift at 1,500 m (4,921 ft) depth,
profiling from 2,000 m (6,562 ft) to the sea surface once every 10 days
to collect profiles of
[[Page 66074]]
temperature and salinity. Moored Oceanographic Sensors--Moored sensors
would capture a range of ice, ocean, and atmospheric conditions on a
year-round basis. These would be bottom anchored, sub-surface moorings
measuring velocity, temperature, and salinity in the upper 500 m (1,640
ft) of the water column. The moorings also collect high-resolution
acoustic measurements of the ice using the ice profilers described
above. Ice velocity and surface waves would be measured by 500 kHz
multibeam sonars from Nortek Signatures. The moored oceanographic
sensors described above use only de minimis sources and are therefore
not anticipated to have the potential for impacts on marine mammals or
their habitat. On-ice Measurements--On-ice measurement systems would be
used to collect weather data. These would include an Autonomous Weather
Station and an Ice Mass Balance Buoy. The Autonomous Weather Station
would be deployed on a tripod; the tripod has insulated foot platforms
that are frozen into the ice. The system would consist of an
anemometer, humidity sensor, and pressure sensor. The Autonomous
Weather Station also includes an altimeter that is de minimis due to
its very high frequency (200 kHz). The Ice Mass Balance Buoy is a 6 m
(20 ft) sensor string, which is deployed through a 5 centimeter (cm; 2
inch (in)) hole drilled into the ice. The string is weighted by a 1
kilogram (kg; 2.2 pound (lb)) lead weight and is supported by a tripod.
The buoy contains a de minimis 200 kHz altimeter and snow depth sensor.
Autonomous Weather Stations and Ice Mass Balance Buoys will be deployed
and will drift with the ice, making measurements until their host ice
floes melt, thus destroying the instruments (likely in summer, roughly
1 year after deployment). After the on-ice instruments are destroyed
they cannot be recovered and would sink to the seafloor as their host
ice floes melted.
Proposed mitigation, monitoring, and reporting measures are
described in detail later in this document (please see Proposed
Mitigation and Proposed Monitoring and Reporting).
Description of Marine Mammals in the Area of Specified Activities
Sections 3 and 4 of the application summarize available information
regarding status and trends, distribution and habitat preferences, and
behavior and life history of the potentially affected species. NMFS
fully considered all of this information, and we refer the reader to
these descriptions, instead of reprinting the information. Additional
information regarding population trends and threats may be found in
NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and
more general information about these species (e.g., physical and
behavioral descriptions) may be found on NMFS' website (https://www.fisheries.noaa.gov/find-species).
Table 3 lists all species or stocks for which take is expected and
proposed to be authorized for this activity and summarizes information
related to the population or stock, including regulatory status under
the MMPA and Endangered Species Act (ESA) and potential biological
removal (PBR), where known. PBR is defined by the MMPA as the maximum
number of animals, not including natural mortalities, that may be
removed from a marine mammal stock while allowing that stock to reach
or maintain its optimum sustainable population (as described in NMFS'
SARs). While no serious injury or mortality is anticipated or proposed
to be authorized here, PBR and annual serious injury and mortality from
anthropogenic sources are included here as gross indicators of the
status of the species or stocks and other threats.
Marine mammal abundance estimates presented in this document
represent the total number of individuals that make up a given stock or
the total number estimated within a particular study or survey area.
NMFS' stock abundance estimates for most species represent the total
estimate of individuals within the geographic area, if known, that
comprises that stock. For some species, this geographic area may extend
beyond U.S. waters. All managed stocks in this region are assessed in
NMFS' U.S. Alaska SARs (Young et al., 2023). All values presented in
table 3 are the most recent available at the time of publication and
are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments.
Table 3--Species Likely Impacted by the Specified Activities \1\
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ESA/MMPA status; Stock abundance (CV,
Common name Scientific name Stock strategic (Y/N) Nmin, most recent PBR Annual M/
\2\ abundance survey) \3\ SI \4\
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Beluga Whale........................ Delphinapterus leucas.. Beaufort Sea........... -, -, N 39,258 (0.229, N/A, UND 104
1992).
Beluga Whale........................ Delphinapterus leucas.. Eastern Chukchi........ -, -, N 13,305 (0.51, 8,875, 178 56
2017).
Ringed Seal......................... Pusa hispida........... Arctic................. T, D, Y UND \5\ (UND, UND, UND 6,459
2013).
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\1\ Information on the classification of marine mammal species can be found on the web page for The Society for Marine Mammalogy's Committee on Taxonomy
(https://marinemammalscience.org/science-and-publications/list-marine-mammal-species-subspecies/).
\2\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR or
which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed under the ESA is
automatically designated under the MMPA as depleted and as a strategic stock.
\3\ NMFS marine mammal stock assessment reports online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
commercial fisheries, vessel strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A
CV associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ A reliable population estimate for the entire stock is not available. Using a sub-sample of data collected from the U.S. portion of the Bering Sea,
an abundance estimate of 171,418 ringed seals has been calculated, but this estimate does not account for availability bias due to seals in the water
or in the shore-fast ice zone at the time of the survey. The actual number of ringed seals in the U.S. portion of the Bering Sea is likely much
higher. Using the Nmin based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a
negatively biased estimate.
As indicated above, both species (with three managed stocks) in
table 3 temporally and spatially co-occur with the activity to the
degree that take is reasonably likely to occur. While bowhead whales
(Balaena mysticetus), gray whales (Eschrichtius robustus), bearded
seals (Erignathus barbatus), spotted seals (Phoca largha), and ribbon
seals (Histriophoca fasciata) have been documented in the area, the
temporal and/or spatial occurrence of these
[[Page 66075]]
species is such that take is not expected to occur, and they are not
discussed further beyond the explanation provided below.
Due to the location of the study area (i.e., northern offshore,
deep water), there were no calculated exposures for the bowhead whale,
gray whale, bearded seal, spotted seal, and ribbon seal from
quantitative modeling of acoustic sources. Bowhead and gray whales are
closely associated with the shallow waters of the continental shelf in
the Beaufort Sea and are unlikely to be exposed to acoustic harassment
from this activity (Young et al., 2023). Gray whales feed primarily in
the Beaufort Sea, Chukchi Sea, and Northwestern Bering Sea during the
summer and fall, but migrate south to winter in Baja California lagoons
(Young et al., 2023). Gray whales are primarily bottom feeders (Swartz
et al., 2006) in water depths of less than 60 m (196.9 ft) (Pike,
1962). Therefore, on the rare occasion that a gray whale does
overwinter in the Beaufort Sea (Stafford et al., 2007), we would expect
an overwintering individual to remain in shallow water over the
continental shelf where it could feed. Spotted seals tend to prefer
pack ice areas with water depths less than 200 m (656.2 ft) during the
spring and move to coastal habitats in the summer and fall, found as
far north as 69-72 degrees N (Muto et al., 2021). Although the study
area includes some waters south of 72 degrees N, the acoustic sources
with the potential to result in take of marine mammals are not found
below that latitude and spotted seals are not expected to be exposed.
Ribbon seals are found year-round in the Bering Sea but may seasonally
range into the Chukchi Sea (Muto et al., 2021). The proposed action
occurs primarily in the Beaufort Sea, outside of the core range of
ribbon seals, thus ribbon seals are not expected to be behaviorally
harassed. Narwhals (Monodon monoceros) are considered extralimital in
the project area and are not expected to be encountered. As no
harassment is expected of the bowhead whale, gray whale, spotted seal,
bearded seal, ribbon seal, and narwhal, these species will not be
discussed further in this proposed notice.
The ONR utilized Conn et al. (2014) in their IHA application as an
abundance estimate for ringed seals, which is based upon aerial
abundance and distribution surveys conducted in the U.S. portion Bering
Sea in 2012 (171,418 ringed seals) (Muto et al., 2021). This value is
likely an underestimate due to the lack of accounting for availability
bias for seals that were in the water at the time of the surveys as
well as not including seals located within the shore-fast ice zone
(Muto et al., 2021). Muto et al. (2021) notes that an accurate
population estimate is likely larger by a factor of two or more.
However, no accepted population estimate is present for Arctic ringed
seals. Therefore, NMFS will also adopt the Conn et al. (2014) abundance
estimate (171,418) for further analyses and discussions on this
proposed action by ONR.
In addition, the polar bear (Ursus maritimus) and Pacific walrus
(Odobenus rosmarus) may be found both on sea ice and/or in the water
within the Beaufort Sea and Chukchi Sea. These species are managed by
the U.S. Fish and Wildlife Service rather than NMFS and, therefore,
they are not considered further in this document.
Beluga Whale
Beluga whales are distributed throughout seasonally ice-covered
arctic and subarctic waters of the Northern Hemisphere (Gurevich,
1980), and are closely associated with open leads and polynyas in ice-
covered regions (Hazard, 1988). Belugas may be either migratory or
residential (non-migratory), depending on the population. Seasonal
distribution is affected by ice cover, tidal conditions, access to
prey, temperature, and human interaction (Frost et al., 1985; Hauser et
al., 2014).
There are five beluga whale stocks recognized within U.S. waters:
Cook Inlet, Bristol Bay, eastern Bering Sea, eastern Chukchi Sea, and
Beaufort Sea. Two stocks, the Beaufort Sea and eastern Chukchi Sea
stocks, have the potential to occur in the location of this proposed
action.
Migratory Biologically Important Areas (BIAs) for belugas in the
eastern Chukchi and Alaskan Beaufort Sea overlap the southern and
western portion of the Study Area (Clarke et al., 2023). A migration
corridor for both stocks of beluga whale includes the eastern Chukchi
Sea through the Beaufort Sea, with the Beaufort Sea stock utilizing the
migratory BIA in April-May and the Eastern Chukchi Sea stock utilizing
portions of the area in November. There are also feeding BIAs for both
stocks throughout the Arctic region (Clarke et al., 2023). During the
winter, they can be found foraging in offshore waters associated with
pack ice. When the sea ice melts in summer, they move to warmer river
estuaries and coastal areas for molting and calving (Muto et al.,
2021). Annual migrations can span over thousands of kilometers. The
residential Beaufort Sea populations participate in short distance
movements within their range throughout the year. Based on satellite
tags (Suydam et al., 2001; Hauser et al., 2014), there is some overlap
in distribution with the eastern Chukchi Sea beluga whale stock.
During the winter, eastern Chukchi Sea belugas occur in offshore
waters associated with pack ice. In the spring, they migrate to warmer
coastal estuaries, bays, and rivers where they may molt (Finley, 1982;
Suydam, 2009), give birth to, and care for their calves (Sergeant and
Brodie, 1969). Eastern Chukchi Sea belugas move into coastal areas,
including Kasegaluk Lagoon (outside of the proposed project site), in
late June and animals are sighted in the area until about mid-July
(Frost and Lowry, 1990; Frost et al., 1993). Satellite tags attached to
eastern Chukchi Sea belugas captured in Kasegaluk Lagoon during the
summer showed these whales traveled 1,100 km (593 nm) north of the
Alaska coastline, into the Canadian Beaufort Sea within three months
(Suydam et al., 2001). Satellite telemetry data from 23 whales tagged
during 1998-2007 suggest variation in movement patterns for different
age and/or sex classes during July-September (Suydam et al., 2005).
Adult males used deeper waters and remained there for the duration of
the summer; all belugas that moved into the Arctic Ocean (north of 75
degrees N) were males, and males traveled through 90 percent pack ice
cover to reach deeper waters in the Beaufort Sea and Arctic Ocean (79-
80 degrees N) by late July/early August. Adult and immature female
belugas remained at or near the shelf break in the south through the
eastern Bering Strait into the northern Bering Sea, remaining north of
Saint Lawrence Island over the winter.
Ringed Seal
Ringed seals are the most common pinniped in the Study Area and
have wide distribution in seasonally and permanently ice-covered waters
of the Northern Hemisphere (North Atlantic Marine Mammal Commission,
2004). Throughout their range, ringed seals have an affinity for ice-
covered waters and are well adapted to occupying both shore-fast and
pack ice (Kelly, 1988). Ringed seals can be found further offshore than
other pinnipeds since they can maintain breathing holes in ice
thickness greater than 2 m (6.6 ft) (Smith and Stirling, 1975). The
breathing holes are maintained by ringed seals using their sharp teeth
and claws found on their fore flippers. They remain in contact with ice
most of the year and use it as a platform for molting in late spring to
early summer, for pupping and nursing in late winter to
[[Page 66076]]
early spring, and for resting at other times of the year (Muto et al.,
2018).
Ringed seals have at least two distinct types of subnivean lairs:
Haulout lairs and birthing lairs (Smith and Stirling, 1975). Haul-out
lairs are typically single-chambered and offer protection from
predators and cold weather. Birthing lairs are larger, multi-chambered
areas that are used for pupping in addition to protection from
predators. Ringed seals pup on both shore-fast ice as well as stable
pack ice. Lentfer (1972) found that ringed seals north of
Utqia[gdot]vik, Alaska, build their subnivean lairs on the pack ice
near pressure ridges. Since subnivean lairs were found north of
Utqia[gdot]vik, Alaska, in pack ice, they are also assumed to be found
within the sea ice in the proposed project site. Ringed seals excavate
subnivean lairs in drifts over their breathing holes in the ice, in
which they rest, give birth, and nurse their pups for 5-9 weeks during
late winter and spring (Chapskii, 1940; McLaren, 1958; Smith and
Stirling, 1975). Ringed seals are born beginning in March but the
majority of births occur in early April. About a month after
parturition, mating begins in late April and early May.
In Alaskan waters, during winter and early spring when sea ice is
at its maximum extent, ringed seals are abundant in the northern Bering
Sea, Norton and Kotzebue Sounds, and throughout the Chukchi and
Beaufort seas (Frost, 1985; Kelly, 1988). Passive acoustic monitoring
of ringed seals from a high frequency recording package deployed at a
depth of 240 m (787 ft) in the Chukchi Sea 120 km (65 nm) north-
northwest of Utqia[gdot]vik, Alaska detected ringed seals in the area
between mid-December and late May over the 4 year study (Jones et al.,
2014). In addition, ringed seals have been observed near and beyond the
outer boundary of the U.S. EEZ (Beland and Ireland, 2010). During the
spring and early summer, ringed seals may migrate north as the ice edge
recedes and spend their summers in the open water period of the
northern Beaufort and Chukchi Seas (Frost, 1985). Foraging-type
movements have been recorded over the continental shelf and north of
the continental shelf waters (Von Duyke et al., 2020). During this
time, sub-adult ringed seals may also occur in the Arctic Ocean Basin
(Hamilton et al., 2015; Hamilton et al., 2017).
With the onset of fall freeze, ringed seal movements become
increasingly restricted and seals will either move west and south with
the advancing ice pack with many seals dispersing throughout the
Chukchi and Bering Seas, or remaining in the Beaufort Sea (Crawford et
al., 2012; Frost and Lowry, 1984; Harwood et al., 2012). Kelly et al.
(2010a) tracked home ranges for ringed seals in the subnivean period
(using shore-fast ice); the size of the home ranges varied from less
than 1 up to 279 km\2\ (median = 0.62 km\2\ for adult males, 0.65 km\2\
for adult females). Most (94 percent) of the home ranges were less than
3 km\2\ during the subnivean period (Kelly et al., 2010a). Near large
polynyas, ringed seals maintain ranges, up to 7,000 km\2\ during winter
and 2,100 km\2\ during spring (Born et al., 2004). Some adult ringed
seals return to the same small home ranges they occupied during the
previous winter (Kelly et al., 2010a). The size of winter home ranges
can vary by up to a factor of 10 depending on the amount of fast ice;
seal movements were more restricted during winters with extensive fast
ice, and were much less restricted where fast ice did not form at high
levels (Harwood et al., 2015).
Of the five recognized subspecies of ringed seals, the Arctic
ringed seal occurs in the Arctic Ocean and Bering Sea and is the only
stock that occurs in U.S. waters. NMFS listed the Arctic ringed seal
subspecies as threatened under the ESA on December 28, 2012 (77 FR
76706), primarily due to anticipated loss of sea ice through the end of
the 21st century. Climate change presents a major concern for the
conservation of ringed seals due to the potential for long-term habitat
loss and modification (Muto et al., 2021). Based upon an analysis of
various life history features and the rapid changes that may occur in
ringed seal habitat, ringed seals are expected to be highly sensitive
to climate change (Laidre et al., 2008; Kelly et al., 2010b).
Critical Habitat
Critical habitat for the ringed seal was designated in May 2022 and
includes marine waters within one specific area in the Bering, Chukchi,
and Beaufort Seas (87 FR 19232, April 1, 2022). Essential features
established by NMFS for conservation of ringed seals are (1) snow-
covered sea ice habitat suitable for the formation and maintenance of
subnivean birth lairs used for sheltering pups during whelping and
nursing, which is defined as waters 3 m (9.8 ft) or more in depth
(relative to Mean Lower Low Water (MLLW)) containing areas of seasonal
land-fast (shore-fast) ice or dense, stable pack ice, that have
undergone deformation and contain snowdrifts of sufficient depth to
form and maintain birth lairs (typically at least 54 cm (21.3 in)
deep); (2) sea ice habitat suitable as a platform for basking and
molting, which is defined as areas containing sea ice of 15 percent or
more concentration in waters 3 m (9.8 ft) or more in depth (relative to
MLLW); and (3) primary prey resources to support Arctic ringed seals,
which are defined to be small, often schooling, fishes, in particular
Arctic cod (Boreogadus saida), saffron cod (Eleginus gracilis), and
rainbow smelt (Osmerus dentex); and small crustaceans, in particular,
shrimps and amphipods.
The Study Area does not overlap with ringed seal critical habitat
(87 FR 19232, April 1, 2022). However, as stated in NMFS' final rule
for the Designation of Critical Habitat for the Arctic Subspecies of
the Ringed Seal (87 FR 19232, April 1, 2022), the area excluded from
the critical habitat contains one or more of the essential features of
the Arctic ringed seal's critical habitat, therefore, even though this
area is excluded from critical habitat designation, habitat with the
physical and biological features essential for ringed seal conservation
is still available to the species, although data are limited to inform
NMFS' assessment of the relative value of this area to the conservation
of the species. As described later and in more detail in the Potential
Effects of Specified Activities on Marine Mammals and Their Habitat
section, we expect minimal impacts to marine mammal habitat as a result
of the ONR's ARA, including impacts to ringed seal sea ice habitat
suitable as a platform for basking and molting and impacts on prey
availability.
Marine Mammal Hearing
Hearing is the most important sensory modality for marine mammals
underwater, and exposure to anthropogenic sound can have deleterious
effects. To appropriately assess the potential effects of exposure to
sound, it is necessary to understand the frequency ranges marine
mammals are able to hear. Not all marine mammal species have equal
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al.
(2007) and Southall et al. (2019) recommended that marine mammals be
divided into hearing groups based on directly measured (behavioral or
auditory evoked potential techniques) or estimated hearing ranges
(behavioral response data, anatomical modeling, etc.). Subsequently,
NMFS (2018) described generalized hearing ranges for these marine
mammal hearing groups. Generalized hearing ranges were chosen based on
the approximately 65 dB threshold from the normalized composite
audiograms, with the exception for lower limits for low-
[[Page 66077]]
frequency cetaceans where the lower bound was deemed to be biologically
implausible and the lower bound from Southall et al. (2007) retained.
Marine mammal hearing groups and their associated hearing ranges are
provided in table 4.
Table 4--Marine Mammal Hearing Groups
[NMFS, 2018]
------------------------------------------------------------------------
Hearing group Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen 7 Hz to 35 kHz.
whales).
Mid-frequency (MF) cetaceans (dolphins, 150 Hz to 160 kHz.
toothed whales, beaked whales, bottlenose
whales).
High-frequency (HF) cetaceans (true 275 Hz to 160 kHz.
porpoises, Kogia, river dolphins,
Cephalorhynchid, Lagenorhynchus cruciger
& L. australis).
Phocid pinnipeds (PW) (underwater) (true 50 Hz to 86 kHz.
seals).
Otariid pinnipeds (OW) (underwater) (sea 60 Hz to 39 kHz.
lions and fur seals).
------------------------------------------------------------------------
\*\ Represents the generalized hearing range for the entire group as a
composite (i.e., all species within the group), where individual
species' hearing ranges are typically not as broad. Generalized
hearing range chosen based on approximately 65 dB threshold from
normalized composite audiogram, with the exception for lower limits
for LF cetaceans (Southall et al., 2007) and PW pinniped
(approximation).
The pinniped functional hearing group was modified from Southall et
al. (2007) on the basis of data indicating that phocid species have
consistently demonstrated an extended frequency range of hearing
compared to otariids, especially in the higher frequency range
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al.,
2013). This division between phocid and otariid pinnipeds is now
reflected in the updated hearing groups proposed in Southall et al.
(2019).
For more detail concerning these groups and associated frequency
ranges, please see NMFS (2018) for a review of available information.
Potential Effects of Specified Activities on Marine Mammals and Their
Habitat
This section provides a discussion of the ways in which components
of the specified activity may impact marine mammals and their habitat.
The Estimated Take of Marine Mammals section later in this document
includes a quantitative analysis of the number of individuals that are
expected to be taken by this activity. The Negligible Impact Analysis
and Determination section considers the content of this section, the
Estimated Take of Marine Mammals section, and the Proposed Mitigation
section, to draw conclusions regarding the likely impacts of these
activities on the reproductive success or survivorship of individuals
and whether those impacts are reasonably expected to, or reasonably
likely to, adversely affect the species or stock through effects on
annual rates of recruitment or survival.
Description of Sound Sources
The marine soundscape is comprised of both ambient and
anthropogenic sounds. Ambient sound is defined as the all-encompassing
sound in a given place and is usually a composite of sound from many
sources both near and far (ANSI, 1995). The sound level of an area is
defined by the total acoustical energy being generated by known and
unknown sources. These sources may include physical (e.g., waves, wind,
precipitation, earthquakes, ice, atmospheric sound), biological (e.g.,
sounds produced by marine mammals, fish, and invertebrates), and
anthropogenic sound (e.g., vessels, dredging, aircraft, construction).
The sum of the various natural and anthropogenic sound sources at
any given location and time--which comprise ``ambient'' or
``background'' sound--depends not only on the source levels (as
determined by current weather conditions and levels of biological and
shipping activity) but also on the ability of sound to propagate
through the environment. In turn, sound propagation is dependent on the
spatially and temporally varying properties of the water column and sea
floor, and is frequency-dependent. As a result of the dependence on a
large number of varying factors, ambient sound levels can be expected
to vary widely over both coarse and fine spatial and temporal scales.
Sound levels at a given frequency and location can vary by 10-20 dB
from day to day (Richardson et al., 1995). The result is that,
depending on the source type and its intensity, sound from the
specified activities may be a negligible addition to the local
environment or could form a distinctive signal that may affect marine
mammals.
Active acoustic sources and icebreaking, if necessary, are proposed
for use in the Study Area. The sounds produced by these activities fall
into one of two general sound types: impulsive and non-impulsive.
Impulsive sounds (e.g., ice explosions, gunshots, sonic booms, impact
pile driving) are typically transient, brief (less than 1 second),
broadband, and consist of high peak sound pressure with rapid rise time
and rapid decay (ANSI, 1986; NIOSH, 1998; NMFS, 2018). Non-impulsive
sounds (e.g., aircraft, machinery operations such as drilling or
dredging, vibratory pile driving, pile cutting, diamond wire sawing,
and active sonar systems) can be broadband, narrowband, or tonal, brief
or prolonged (continuous or intermittent), and typically do not have
the high peak sound pressure with raid rise/decay time that impulsive
sounds do (ANSI, 1986; NIOSH, 1998; NMFS, 2018). The distinction
between these two sound types is important because they have differing
potential to cause physical effects, particularly with regard to
hearing (e.g., Ward, 1997; Southall et al., 2007).
The likely or possible impacts of the ONR's proposed action on
marine mammals involve both non-acoustic and acoustic stressors.
Potential non-acoustic stressors could result from the physical
presence of vessels, equipment, and personnel (e.g., icebreaking
impacts, vessel and in-water vehicle strike, and bottom disturbance);
however, any impacts to marine mammals are expected to primarily be
acoustic in nature (e.g., non-impulsive acoustic sources, noise from
icebreaking vessel (``icebreaking noise''), and vessel noise).
Acoustic Impacts
The introduction of anthropogenic noise into the aquatic
environment from active acoustic sources and noise from icebreaking is
the means by which marine mammals may be harassed from the ONR's
specified activity. In general, animals exposed to natural or
anthropogenic sound may experience behavioral, physiological, and/or
physical effects, ranging in magnitude from none to severe (Southall et
al., 2007). In general, exposure to pile driving noise has the
potential to result in behavioral reactions (e.g., avoidance, temporary
cessation of foraging and vocalizing, changes in dive behavior) and, in
limited cases, an auditory threshold shift (TS). Exposure to
anthropogenic noise can also lead to non-observable physiological
responses such an increase in stress hormones. Additional noise in a
marine mammal's habitat can mask acoustic cues used by marine mammals
to carry out daily functions such as communication and predator and
prey detection. The effects
[[Page 66078]]
of pile driving noise on marine mammals are dependent on several
factors, including, but not limited to, sound type (e.g., impulsive
versus non-impulsive), the species, age and sex class (e.g., adult male
versus mother with calf), duration of exposure, the distance between
the pile and the animal, received levels, behavior at time of exposure,
and previous history with exposure (Wartzok et al., 2004; Southall et
al., 2007). Here we discuss physical auditory effects (i.e., TS)
followed by behavioral effects and potential impacts on habitat.
NMFS defines a noise-induced TS as a change, usually an increase,
in the threshold of audibility at a specified frequency or portion of
an individual's hearing range above a previously established reference
level (NMFS, 2018). The amount of TS is customarily expressed in dB and
TS can be permanent or temporary. As described in NMFS (2018), there
are numerous factors to consider when examining the consequence of TS,
including, but not limited to, the signal temporal pattern (e.g.,
impulsive or non-impulsive), likelihood an individual would be exposed
for a long enough duration or to a high enough level to induce a TS,
the magnitude of the TS, time to recovery (seconds to minutes or hours
to days), the frequency range of the exposure (i.e., spectral content),
the hearing and vocalization frequency range of the exposed species
relative to the signal's frequency spectrum (i.e., how animal uses
sound within the frequency band of the signal) (Kastelein et al.,
2014), and the overlap between the animal and the source (e.g.,
spatial, temporal, and spectral).
Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,
irreversible increase in the threshold of audibility at a specified
frequency or portion of an individual's hearing range above a
previously established reference level (NMFS, 2018). Available data
from humans and other terrestrial mammals indicate that a 40 dB TS
approximates PTS onset (see Ward et al., 1958; Ward et al., 1959; Ward,
1960; Kryter et al., 1966; Miller, 1974; Ahroon et al., 1996; Henderson
et al., 2008). PTS levels for marine mammals are estimates as, with the
exception of a single study unintentionally inducing PTS in a harbor
seal (e.g., Kastak et al., 2008), there are no empirical data measuring
PTS in marine mammals largely due to the fact that, for various ethical
reasons, experiments involving anthropogenic noise exposure at levels
inducing PTS are not typically pursued or authorized (NMFS, 2018).
Temporary Threshold Shift (TTS)--TTS is a temporary, reversible
increase in the threshold of audibility at a specified frequency or
portion of an individual's hearing range above a previously established
reference level (NMFS, 2018). Based on data from cetacean TTS
measurements (see Southall et al., 2007), a TTS of 6 dB is considered
the minimum TS clearly larger than any day-to-day or session-to-session
variation in a subject's normal hearing ability (Finneran et al., 2000;
Schlundt et al., 2000; Finneran et al., 2002). As described in Finneran
(2016), marine mammal studies have shown the amount of TTS increases
with cumulative sound exposure level (SELcum) in an
accelerating fashion: At low exposures with lower SELcum,
the amount of TTS is typically small and the growth curves have shallow
slopes. At exposures with higher SELcum, the growth curves
become steeper and approach linear relationships with the noise SEL.
Depending on the degree (elevation of threshold in dB), duration
(i.e., recovery time), and frequency range of TTS, and the context in
which it is experienced, TTS can have effects on marine mammals ranging
from discountable to serious (similar to those discussed in the
Auditory Masking section). For example, a marine mammal may be able to
readily compensate for a brief, relatively small amount of TTS in a
non-critical frequency range that takes place during a time when the
animal is traveling through the open ocean, where ambient noise is
lower and there are not as many competing sounds present.
Alternatively, a larger amount and longer duration of TTS sustained
during time when communication is critical for successful mother/calf
interactions could have more serious impacts. We note that reduced
hearing sensitivity as a simple function of aging has been observed in
marine mammals, as well as humans and other taxa (Southall et al.,
2007), so we can infer that strategies exist for coping with this
condition to some degree, though likely not without cost.
Many studies have examined noise-induced hearing loss in marine
mammals (see Finneran, 2015; Southall et al., 2019 for summaries). TTS
is the mildest form of hearing impairment that can occur during
exposure to sound (Kryter et al., 1966). While experiencing TTS, the
hearing threshold rises, and a sound must be at a higher level in order
to be heard. In terrestrial and marine mammals, TTS can last from
minutes or hours to days (in cases of strong TTS). In many cases,
hearing sensitivity recovers rapidly after exposure to the sound ends.
For cetaceans, published data on the onset of TTS are limited to
captive bottlenose dolphin (Tursiops truncatus), beluga whale, harbor
porpoise (Phocoena phocoena), and Yangtze finless porpoise (Neophocoena
asiaeorientalis) (Southall et al., 2019). For pinnipeds in water,
measurements of TTS are limited to harbor seals (Phoca vitulina),
elephant seals (Mirounga angustirostris), bearded seals, and California
sea lions (Zalophus californianus) (Kastak et al., 1999; Kastak et al.,
2008; Kastelein et al., 2020b; Reichmuth et al., 2013; Sills et al.,
2020). TTS was not observed in spotted and ringed seals exposed to
single airgun impulse sounds at levels matching previous predictions of
TTS onset (Reichmuth et al., 2016). These studies examine hearing
thresholds measured in marine mammals before and after exposure to
intense or long-duration sound exposure. The difference between the
pre-exposure and post-exposure thresholds can be used to determine the
amount of threshold shift at various post-exposure times.
The amount and onset of TTS depends on the exposure frequency.
Sounds at low frequencies, well below the region of best sensitivity
for a species or hearing group, are less hazardous than those at higher
frequencies, near the region of best sensitivity (Finneran and
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are
higher compared to those in the region of best sensitivity (i.e., a low
frequency noise would need to be louder to cause TTS onset when TTS
exposure level is higher), as shown for harbor porpoises and harbor
seals (Kastelein et al., 2019a; Kastelein et al., 2019b; Kastelein et
al., 2020a; Kastelein et al., 2020b). Note that in general, harbor
seals and harbor porpoises have a lower TTS onset than other measured
pinniped or cetacean species (Finneran, 2015). In addition, TTS can
accumulate across multiple exposures but the resulting TTS will be less
than the TTS from a single, continuous exposure with the same SEL
(Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014;
Kastelein et al., 2015). This means that TTS predictions based on the
total SELcum will overestimate the amount of TTS from
intermittent exposures, such as sonars and impulsive sources.
Nachtigall et al. (2018) describe measurements of hearing sensitivity
of multiple odontocete species (bottlenose dolphin, harbor porpoise,
beluga whale, and false killer whale (Pseudorca crassidens)) when a
relatively loud sound was preceded by a warning
[[Page 66079]]
sound. These captive animals were shown to reduce hearing sensitivity
when warned of an impending intense sound. Based on these experimental
observations of captive animals, the authors suggest that wild animals
may dampen their hearing during prolonged exposures or if conditioned
to anticipate intense sounds. Another study showed that echolocating
animals (including odontocetes) might have anatomical specializations
that might allow for conditioned hearing reduction and filtering of
low-frequency ambient noise, including increased stiffness and control
of middle ear structures and placement of inner ear structures (Ketten
et al., 2021). Data available on noise-induced hearing loss for
mysticetes are currently lacking (NMFS, 2018). Additionally, the
existing marine mammal TTS data come from a limited number of
individuals within these species.
Relationships between TTS and PTS thresholds have not been studied
in marine mammals and there is no PTS data for cetaceans, but such
relationships are assumed to be similar to those in humans and other
terrestrial mammals. PTS typically occurs at exposure levels at least
several decibels above that inducing mild TTS (e.g., a 40-dB threshold
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007;
Southall et al., 2019). Based on data from terrestrial mammals, a
precautionary assumption is that the PTS thresholds for impulsive
sounds (such as impact pile driving pulses as received close to the
source) are at least 6 dB higher than the TTS threshold on a peak-
pressure basis and PTS cumulative sound exposure level thresholds are
15 to 20 dB higher than TTS cumulative sound exposure level thresholds
(Southall et al., 2007; Southall et al., 2019). Given the higher level
of sound or longer exposure duration necessary to cause PTS as compared
with TTS, it is considerably less likely that PTS could occur.
Activities for this project include active acoustics, equipment
deployment and recovery, and, potentially, icebreaking. For the
proposed action, these activities would not occur at the same time and
there would likely be pauses in activities producing the sound during
each day. Given these pauses and that many marine mammals are likely
moving through the Study Area and not remaining for extended periods of
time, the potential for TS declines.
Behavioral Harassment--Exposure to noise from pile driving and
drilling also has the potential to behaviorally disturb marine mammals.
Generally speaking, NMFS considers a behavioral disturbance that rises
to the level of harassment under the MMPA a non-minor response--in
other words, not every response qualifies as behavioral disturbance,
and for responses that do, those of a higher level, or accrued across a
longer duration, have the potential to affect foraging, reproduction,
or survival. Behavioral disturbance may include a variety of effects,
including subtle changes in behavior (e.g., minor or brief avoidance of
an area or changes in vocalizations), more conspicuous changes in
similar behavioral activities, and more sustained and/or potentially
severe reactions, such as displacement from or abandonment of high-
quality habitat. Behavioral responses may include changing durations of
surfacing and dives, changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral
activities (such as socializing or feeding); eliciting a visible
startle response or aggressive behavior (such as tail/fin slapping or
jaw clapping); avoidance of areas where sound sources are located.
Pinnipeds may increase their haul out time, possibly to avoid in-water
disturbance (Thorson and Reyff, 2006). Behavioral responses to sound
are highly variable and context-specific and any reactions depend on
numerous intrinsic and extrinsic factors (e.g., species, state of
maturity, experience, current activity, reproductive state, auditory
sensitivity, time of day), as well as the interplay between factors
(e.g., Richardson et al., 1995; Wartzok et al., 2004; Southall et al.,
2007; Southall et al., 2019; Weilgart, 2007; Archer et al., 2010).
Behavioral reactions can vary not only among individuals but also
within an individual, depending on previous experience with a sound
source, context, and numerous other factors (Ellison et al., 2012), and
can vary depending on characteristics associated with the sound source
(e.g., whether it is moving or stationary, number of sources, distance
from the source). In general, pinnipeds seem more tolerant of, or at
least habituate more quickly to, potentially disturbing underwater
sound than do cetaceans, and generally seem to be less responsive to
exposure to industrial sound than most cetaceans. Please see Appendices
B and C of Southall et al. (2007) and Gomez et al. (2016) for reviews
of studies involving marine mammal behavioral responses to sound.
Habituation can occur when an animal's response to a stimulus wanes
with repeated exposure, usually in the absence of unpleasant associated
events (Wartzok et al., 2004). Animals are most likely to habituate to
sounds that are predictable and unvarying. It is important to note that
habituation is appropriately considered as a ``progressive reduction in
response to stimuli that are perceived as neither aversive nor
beneficial,'' rather than as, more generally, moderation in response to
human disturbance (Bejder et al., 2009). The opposite process is
sensitization, when an unpleasant experience leads to subsequent
responses, often in the form of avoidance, at a lower level of
exposure.
As noted above, behavioral state may affect the type of response.
For example, animals that are resting may show greater behavioral
change in response to disturbing sound levels than animals that are
highly motivated to remain in an area for feeding (Richardson et al.,
1995; Wartzok et al., 2004; NRC, 2005). Controlled experiments with
captive marine mammals have showed pronounced behavioral reactions,
including avoidance of loud sound sources (Ridgway et al., 1997;
Finneran et al., 2003). Observed responses of wild marine mammals to
loud pulsed sound sources (e.g., seismic airguns) have been varied but
often consist of avoidance behavior or other behavioral changes
(Richardson et al., 1995; Morton and Symonds, 2002; Nowacek et al.,
2007).
Available studies show wide variation in response to underwater
sound; therefore, it is difficult to predict specifically how any given
sound in a particular instance might affect marine mammals perceiving
the signal. If a marine mammal does react briefly to an underwater
sound by changing its behavior or moving a small distance, the impacts
of the change are unlikely to be significant to the individual, let
alone the stock or population. However, if a sound source displaces
marine mammals from an important feeding or breeding area for a
prolonged period, impacts on individuals and populations could be
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC,
2005). However, there are broad categories of potential response, which
we describe in greater detail here, that include alteration of dive
behavior, alteration of foraging behavior, effects to breathing,
interference with or alteration of vocalization, avoidance, and flight.
Changes in dive behavior can vary widely and may consist of
increased or decreased dive times and surface intervals as well as
changes in the rates of ascent and descent during a dive (e.g., Frankel
and Clark, 2000; Nowacek et al., 2004; Goldbogen et al., 2013a;
Goldbogen et al., 2013b). Variations in dive behavior may reflect
interruptions
[[Page 66080]]
in biologically significant activities (e.g., foraging) or they may be
of little biological significance. The impact of an alteration to dive
behavior resulting from an acoustic exposure depends on what the animal
is doing at the time of the exposure and the type and magnitude of the
response.
Disruption of feeding behavior can be difficult to correlate with
anthropogenic sound exposure, so it is usually inferred by observed
displacement from known foraging areas, the appearance of secondary
indicators (e.g., bubble nets or sediment plumes), or changes in dive
behavior. As for other types of behavioral response, the frequency,
duration, and temporal pattern of signal presentation, as well as
differences in species sensitivity, are likely contributing factors to
differences in response in any given circumstance (e.g., Croll et al.,
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al.,
2007). A determination of whether foraging disruptions incur fitness
consequences would require information on or estimates of the energetic
requirements of the affected individuals and the relationship between
prey availability, foraging effort and success, and the life history
stage of the animal.
Variations in respiration naturally vary with different behaviors
and alterations to breathing rate as a function of acoustic exposure
can be expected to co-occur with other behavioral reactions, such as a
flight response or an alteration in diving. However, respiration rates
in and of themselves may be representative of annoyance or an acute
stress response. Various studies have shown that respiration rates may
either be unaffected or could increase, depending on the species and
signal characteristics, again highlighting the importance in
understanding species differences in the tolerance of underwater noise
when determining the potential for impacts resulting from anthropogenic
sound exposure (e.g., Kastelein et al., 2005; Kastelein et al., 2006).
For example, harbor porpoise' respiration rate increased in response to
pile driving sounds at and above a received broadband SPL of 136 dB
(zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike: 127 dB re 1
[mu]Pa\2\-s) (Kastelein et al., 2013).
Marine mammals vocalize for different purposes and across multiple
modes, such as whistling, echolocation click production, calling, and
singing. Changes in vocalization behavior in response to anthropogenic
noise can occur for any of these modes and may result from a need to
compete with an increase in background noise or may reflect increased
vigilance or a startle response. For example, in the presence of
potentially masking signals, humpback whales and killer whales have
been observed to increase the length of their songs (Miller et al.,
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004),
respectively, while North Atlantic right whales (Eubalaena glacialis)
have been observed to shift the frequency content of their calls upward
while reducing the rate of calling in areas of increased anthropogenic
noise (Parks et al., 2007). In some cases, animals may cease sound
production during production of aversive signals (Bowles et al., 1994).
Avoidance is the displacement of an individual from an area or
migration path as a result of the presence of a sound or other
stressors, and is one of the most obvious manifestations of disturbance
in marine mammals (Richardson et al., 1995). Avoidance may be short-
term, with animals returning to the area once the noise has ceased
(e.g., Bowles et al., 1994; Morton and Symonds, 2002). Longer-term
displacement is possible, however, which may lead to changes in
abundance or distribution patterns of the affected species in the
affected region if habituation to the presence of the sound does not
occur (e.g., Blackwell et al., 2004; Bejder et al., 2006).
A flight response is a dramatic change in normal movement to a
directed and rapid movement away from the perceived location of a sound
source. The flight response differs from other avoidance responses in
the intensity of the response (e.g., directed movement, rate of
travel). Relatively little information on flight responses of marine
mammals to anthropogenic signals exist, although observations of flight
responses to the presence of predators have occurred (Connor and
Heithaus, 1996; Bowers et al., 2018). The result of a flight response
could range from brief, temporary exertion and displacement from the
area where the signal provokes flight to, in extreme cases, marine
mammal strandings (Evans and England, 2001). However, it should be
noted that response to a perceived predator does not necessarily invoke
flight (Ford and Reeves, 2008), and whether individuals are solitary or
in groups may influence the response.
Behavioral disturbance can also impact marine mammals in more
subtle ways. Increased vigilance may result in costs related to
diversion of focus and attention (i.e., when a response consists of
increased vigilance, it may come at the cost of decreased attention to
other critical behaviors such as foraging or resting). These effects
have generally not been demonstrated for marine mammals, but studies
involving fishes and terrestrial animals have shown that increased
vigilance may substantially reduce feeding rates (e.g., Beauchamp and
Livoreil, 1997; Purser and Radford, 2011; Fritz et al., 2002). In
addition, chronic disturbance can cause population declines through
reduction of fitness (e.g., decline in body condition) and subsequent
reduction in reproductive success, survival, or both (e.g., Daan et
al., 1996; Bradshaw et al., 1998). However, Ridgway et al. (2006)
reported that increased vigilance in bottlenose dolphins exposed to
sound over a 5-day period did not cause any sleep deprivation or stress
effects.
Many animals perform vital functions, such as feeding, resting,
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption
of such functions resulting from reactions to stressors such as sound
exposure are more likely to be significant if they last more than one
diel cycle or recur on subsequent days (Southall et al., 2007).
Consequently, a behavioral response lasting less than 1 day and not
recurring on subsequent days is not considered particularly severe
unless it could directly affect reproduction or survival (Southall et
al., 2007). Note that there is a difference between multi-day
substantive (i.e., meaningful) behavioral reactions and multi-day
anthropogenic activities. For example, just because an activity lasts
for multiple days does not necessarily mean that individual animals are
either exposed to activity-related stressors for multiple days or,
further, exposed in a manner resulting in sustained multi-day
substantive behavioral responses.
Behavioral Responses to Icebreaking Noise--Ringed seals on pack ice
showed various behaviors when approached by an icebreaking vessel. A
majority of seals dove underwater when the ship was within 0.93 km (0.5
nm) while others remained on the ice. However, as icebreaking vessels
came closer to the seals, most dove underwater. Ringed seals have also
been observed foraging in the wake of an icebreaking vessel (Richardson
et al., 1995) and may have preferentially established breathing holes
in the ship tracks after the ice-breaker moved through the area.
Previous observations and studies using icebreaking ships provide a
greater understanding in how seal behavior may be affected by a vessel
transiting through the area.
Adult ringed seals spend up to 20 percent of the time in subnivean
lairs during the winter season (Kelly et al.,
[[Page 66081]]
2010a). Ringed seal pups spend about 50 percent of their time in the
lair during the nursing period (Lydersen and Hammill, 1993). During the
warm season ringed seals haul out on the ice. In a study of ringed seal
haul out activity by Born et al. (2002), ringed seals spent 25-57
percent of their time hauled out in June, which is during their molting
season. Ringed seal lairs are typically used by individual seals
(haulout lairs) or by a mother with a pup (birthing lairs); large lairs
used by many seals for hauling out are rare (Smith and Stirling, 1975).
If the non-impulsive acoustic transmissions are heard and are perceived
as a threat, ringed seals within subnivean lairs could react to the
sound in a similar fashion to their reaction to other threats, such as
polar bears (their primary predators), although the type of sound would
be novel to them. Responses of ringed seals to a variety of human-
induced sounds (e.g., helicopter noise, snowmobiles, dogs, people, and
seismic activity) have been variable; some seals entered the water and
some seals remained in the lair. However, in all instances in which
observed seals departed lairs in response to noise disturbance, they
subsequently reoccupied the lair (Kelly et al., 1988).
Ringed seal mothers have a strong bond with their pups and may
physically move their pups from the birth lair to an alternate lair to
avoid predation, sometimes risking their lives to defend their pups
from potential predators. If a ringed seal mother perceives the
proposed acoustic sources as a threat, the network of multiple birth
and haulout lairs allows the mother and pup to move to a new lair
(Smith and Stirling, 1975; Smith and Hammill, 1981). The acoustic
sources from this proposed action are not likely to impede a ringed
seal from finding a breathing hole or lair, as captive seals have been
found to primarily use vision to locate breathing holes and no effect
to ringed seal vision would occur from the acoustic disturbance (Elsner
et al., 1989; Wartzok et al., 1992). It is anticipated that a ringed
seal would be able to relocate to a different breathing hole relatively
easily without impacting their normal behavior patterns.
Stress responses--An animal's perception of a threat may be
sufficient to trigger stress responses consisting of some combination
of behavioral responses, autonomic nervous system responses,
neuroendocrine responses, or immune responses (e.g., Selye, 1950;
Moberg, 2000). In many cases, an animal's first and sometimes most
economical (in terms of energetic costs) response is behavioral
avoidance of the potential stressor. Autonomic nervous system responses
to stress typically involve changes in heart rate, blood pressure, and
gastrointestinal activity. These responses have a relatively short
duration and may or may not have a significant long-term effect on an
animal's fitness.
Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that
are affected by stress--including immune competence, reproduction,
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been
implicated in failed reproduction, altered metabolism, reduced immune
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha,
2000). Increases in the circulation of glucocorticoids are also equated
with stress (Romano et al., 2004).
The primary distinction between stress (which is adaptive and does
not normally place an animal at risk) and ``distress'' is the cost of
the response. During a stress response, an animal uses glycogen stores
that can be quickly replenished once the stress is alleviated. In such
circumstances, the cost of the stress response would not pose serious
fitness consequences. However, when an animal does not have sufficient
energy reserves to satisfy the energetic costs of a stress response,
energy resources must be diverted from other functions. This state of
distress will last until the animal replenishes its energetic reserves
sufficient to restore normal function.
Relationships between these physiological mechanisms, animal
behavior, and the costs of stress responses are well-studied through
controlled experiments for both laboratory and free-ranging animals
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003;
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to
exposure to anthropogenic sounds or other stressors and their effects
on marine mammals have also been reviewed (Fair and Becker, 2000;
Romano et al., 2002b) and, more rarely, studied in wild populations
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found
that noise reduction from reduced vessel traffic in the Bay of Fundy
was associated with decreased stress in North Atlantic right whales.
These and other studies lead to a reasonable expectation that some
marine mammals will experience physiological stress responses upon
exposure to acoustic stressors and that it is possible that some of
these would be classified as ``distress.'' In addition, any animal
experiencing TTS would likely also experience stress responses (NRC,
2003), however, distress is an unlikely result of the proposed project
based on observations of marine mammals during previous, similar
projects in the region.
Auditory Masking--Since many marine mammals rely on sound to find
prey, moderate social interactions, and facilitate mating (Tyack,
2008), noise from anthropogenic sound sources can interfere with these
functions, but only if the noise spectrum overlaps with the hearing
sensitivity of the receiving marine mammal (Southall et al., 2007;
Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive,
though not high-intensity, noise could cause masking at particular
frequencies for marine mammals that utilize sound for vital biological
functions (Clark et al., 2009). Acoustic masking is when other noises
such as from human sources interfere with an animal's ability to
detect, recognize, or discriminate between acoustic signals of interest
(e.g., those used for intraspecific communication and social
interactions, prey detection, predator avoidance, navigation)
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain
circumstances, marine mammals whose acoustical sensors or environment
are being severely masked could also be impaired from maximizing their
performance fitness in survival and reproduction. The ability of a
noise source to mask biologically important sounds depends on the
characteristics of both the noise source and the signal of interest
(e.g., signal-to-noise ratio, temporal variability, direction), in
relation to each other and to an animal's hearing abilities (e.g.,
sensitivity, frequency range, critical ratios, frequency
discrimination, directional discrimination, age or TTS hearing loss),
and existing ambient noise and propagation conditions (Hotchkin and
Parks, 2013).
Under certain circumstances, marine mammals experiencing
significant masking could also be impaired from maximizing their
performance fitness in survival and reproduction. Therefore, when the
coincident (masking) sound is human-made, it may be considered
harassment when disrupting or altering critical behaviors. It is
important to distinguish TTS and PTS, which persist after the sound
exposure, from masking, which occurs during the sound exposure. Because
masking (without resulting in TS) is not associated with abnormal
physiological function, it is not considered a physiological effect,
but rather a potential behavioral effect
[[Page 66082]]
(though not necessarily one that would be associated with harassment).
The frequency range of the potentially masking sound is important
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation
sounds produced by odontocetes but are more likely to affect detection
of mysticete communication calls and other potentially important
natural sounds such as those produced by surf and some prey species.
The masking of communication signals by anthropogenic noise may be
considered as a reduction in the communication space of animals (e.g.,
Clark et al., 2009) and may result in energetic or other costs as
animals change their vocalization behavior (e.g., Miller et al., 2000;
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt
et al., 2009). Masking can be reduced in situations where the signal
and noise come from different directions (Richardson et al., 1995),
through amplitude modulation of the signal, or through other
compensatory behaviors (Hotchkin and Parks, 2013). Masking can be
tested directly in captive species (e.g., Erbe, 2008), but in wild
populations it must be either modeled or inferred from evidence of
masking compensation. There are few studies addressing real-world
masking sounds likely to be experienced by marine mammals in the wild
(e.g., Branstetter et al., 2013).
Marine mammals at or near the proposed project site may be exposed
to anthropogenic noise which may be a source of masking. Vocalization
changes may result from a need to compete with an increase in
background noise and include increasing the source level, modifying the
frequency, increasing the call repetition rate of vocalizations, or
ceasing to vocalize in the presence of increased noise (Hotchkin and
Parks, 2013). For example, in response to loud noise, beluga whales may
shift the frequency of their echolocation clicks to prevent masking by
anthropogenic noise (Eickmeier and Vallarta, 2023).
Masking is more likely to occur in the presence of broadband,
relatively continuous noise sources such as vibratory pile driving.
Energy distribution of pile driving covers a broad frequency spectrum,
and sound from pile driving would be within the audible range of
pinnipeds and cetaceans present in the proposed action area. While
icebreaking during the ONR's proposed action may mask some acoustic
signals that are relevant to the daily behavior of marine mammals, the
short-term duration (up to 8 days) and limited areas affected make it
very unlikely that the fitness of individual marine mammals would be
impacted.
Potential Effects on Prey--The marine mammal species in the Study
Area feed on marine invertebrates and fish. Studies of sound energy
effects on invertebrates are few, and primarily identify behavioral
responses. It is expected that most marine invertebrates would not
sense the frequencies of the acoustic transmissions from the acoustic
sources associated with the proposed action. Although acoustic sources
used during the proposed action may briefly impact individuals,
intermittent exposures to non-impulsive acoustic sources are not
expected to impact survival, growth, recruitment, or reproduction of
widespread marine invertebrate populations.
The fish species residing in the study area include those that are
closely associated with the deep ocean habitat of the Beaufort Sea.
Nearly 250 marine fish species have been described in the Arctic,
excluding the larger parts of the sub-Arctic Bering, Barents, and
Norwegian Seas (Mecklenburg et al., 2011). However, only about 30 are
known to occur in the Arctic waters of the Beaufort Sea (Christiansen
and Reist, 2013). Although hearing capability data only exist for fewer
than 100 of the 32,000 named fish species, current data suggest that
most species of fish detect sounds from 50 to 100 Hz, with few fish
hearing sounds above 4 kHz (Popper, 2008). It is believed that most
fish have the best hearing sensitivity from 100 to 400 Hz (Popper,
2003). Fish species in the study area are expected to hear the low-
frequency sources associated with the proposed action, but most are not
expected to detect sound from the mid-frequency sources. Human
generated sound could alter the behavior of a fish in a manner than
would affect its way of living, such as where it tries to locate food
or how well it could find a mate. Behavioral responses to loud noise
could include a startle response, such as the fish swimming away from
the source, the fish ``freezing'' and staying in place, or scattering
(Popper, 2003). Misund (1997) found that fish ahead of a ship showed
avoidance reactions at ranges of 49-149 m (160-489 ft). Avoidance
behavior of vessels, vertically or horizontally in the water column,
has been reported for cod and herring, and was attributed to vessel
noise. While acoustic sources associated with the proposed action may
influence the behavior of some fish species, other fish species may be
equally unresponsive. Overall effects to fish from the proposed action
would be localized, temporary, and infrequent.
Effects to Physical and Foraging Habitat--Ringed seals haul out on
pack ice during the spring and summer to molt (Reeves et al., 2002;
Born et al., 2002). Additionally, some studies suggested that ringed
seals might preferentially establish breathing holes in ship tracks
after vessels move through the area (Alliston, 1980; Alliston, 1981).
The amount of ice habitat disturbed by activities is small relative to
the amount of overall habitat available and there will be no permanent
or longer-term loss or modification of physical ice habitat used by
ringed seals. Vessel movement would have minimal effect on physical
beluga habitat as beluga habitat is solely within the water column.
Furthermore, the deployed sources that would remain in use after the
vessels have left the survey area have low duty cycles and lower source
levels, and any impacts to the acoustic habitat of marine mammals would
be minimal.
Estimated Take of Marine Mammals
This section provides an estimate of the number of incidental takes
proposed for authorization through the IHA, which will inform NMFS'
consideration of the negligible impact determinations and impacts on
subsistence uses.
Harassment is the only type of take expected to result from these
activities. For this military readiness activity, the MMPA defines
``harassment'' as (i) Any act that injures or has the significant
potential to injure a marine mammal or marine mammal stock in the wild
(Level A harassment); or (ii) Any act that disturbs or is likely to
disturb a marine mammal or marine mammal stock in the wild by causing
disruption of natural behavioral patterns, including, but not limited
to, migration, surfacing, nursing, breeding, feeding, or sheltering, to
a point where the behavioral patterns are abandoned or significantly
altered (Level B harassment).
Authorized takes would be by Level B harassment only, in the form
of direct behavioral disturbances and/or TTS for individual marine
mammals resulting from exposure to active acoustic transmissions and
icebreaking. Based on the nature of the activity, Level A harassment is
neither anticipated nor proposed to be authorized.
As described previously, no serious injury or mortality is
anticipated or proposed to be authorized for this activity. Below we
describe how the proposed take numbers are estimated.
For acoustic impacts, generally speaking, we estimate take by
considering: (1) acoustic thresholds
[[Page 66083]]
above which NMFS believes the best available science indicates marine
mammals will be behaviorally harassed or incur some degree of permanent
hearing impairment; (2) the area or volume of water that will be
ensonified above these levels in a day; (3) the density or occurrence
of marine mammals within these ensonified areas; and, (4) the number of
days of activities. We note that while these factors can contribute to
a basic calculation to provide an initial prediction of potential
takes, additional information that can qualitatively inform take
estimates is also sometimes available (e.g., previous monitoring
results or average group size). Below, we describe the factors
considered here in more detail and present the proposed take estimates.
Acoustic Thresholds
NMFS recommends the use of acoustic thresholds that identify the
received level of underwater sound above which exposed marine mammals
would be reasonably expected to be behaviorally harassed (equated to
Level B harassment) or to incur PTS of some degree (equated to Level A
harassment). Thresholds have also been developed identifying the
received level of in-air sound above which exposed pinnipeds would
likely be behaviorally harassed.
Level B Harassment
Though significantly driven by received level, the onset of
behavioral disturbance from anthropogenic noise exposure is also
informed to varying degrees by other factors related to the source or
exposure context (e.g., frequency, predictability, duty cycle, duration
of the exposure, signal-to-noise ratio, distance to the source), the
environment (e.g., bathymetry, other noises in the area, predators in
the area), and the receiving animals (hearing, motivation, experience,
demography, life stage, depth) and can be difficult to predict (e.g.,
Southall et al., 2007; Southall et al., 2021; Ellison et al., 2012).
Based on what the available science indicates and the practical need to
use a threshold based on a metric that is both predictable and
measurable for most activities, NMFS typically uses a generalized
acoustic threshold based on received level to estimate the onset of
behavioral harassment. NMFS generally predicts that marine mammals are
likely to be behaviorally harassed in a manner considered to be Level B
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB re 1 [mu]Pa
for continuous (e.g., vibratory pile driving, drilling) and above RMS
SPL 160 dB re 1 [mu]Pa for non-explosive impulsive (e.g., seismic
airguns) or intermittent (e.g., scientific sonar) sources. Generally
speaking, Level B harassment estimates based on these behavioral
harassment thresholds are expected to include any likely takes by TTS
as, in most cases, the likelihood of TTS occurs at distances from the
source less than those at which behavioral harassment is likely. TTS of
a sufficient degree can manifest as behavioral harassment, as reduced
hearing sensitivity and the potential reduced opportunities to detect
important signals (conspecific communication, predators, prey) may
result in changes in behavior patterns that would not otherwise occur.
In this case, NMFS is proposing to adopt the ONR's approach to
estimating incidental take by Level B harassment from the active
acoustic sources for this action, which includes use of dose response
functions. The ONR's dose response functions were developed to estimate
take from sonar and similar transducers, but are not applicable to
icebreaking. Multi-year research efforts have conducted sonar exposure
studies for odontocetes and mysticetes (Miller et al., 2012; Sivle et
al., 2012). Several studies with captive animals have provided data
under controlled circumstances for odontocetes and pinnipeds (Houser et
al., 2013b; Houser et al., 2013a). Moretti et al. (2014) published a
beaked whale dose-response curve based on passive acoustic monitoring
of beaked whales during U.S. Navy training activity at Atlantic
Underwater Test and Evaluation Center during actual Anti-Submarine
Warfare exercises. This information necessitated the update of the
behavioral response criteria for the U.S. Navy's environmental
analyses.
Southall et al. (2007), and more recently (Southall et al., 2019),
synthesized data from many past behavioral studies and observations to
determine the likelihood of behavioral reactions at specific sound
levels. While in general, the louder the sound source the more intense
the behavioral response, it was clear that the proximity of a sound
source and the animal's experience, motivation, and conditioning were
also critical factors influencing the response (Southall et al., 2007;
Southall et al., 2019). After examining all of the available data, the
authors felt that the derivation of thresholds for behavioral response
based solely on exposure level was not supported because context of the
animal at the time of sound exposure was an important factor in
estimating response. Nonetheless, in some conditions, consistent
avoidance reactions were noted at higher sound levels depending on the
marine mammal species or group allowing conclusions to be drawn. Phocid
seals showed avoidance reactions at or below 190 dB re 1 [mu]Pa at 1 m;
thus, seals may actually receive levels adequate to produce TTS before
avoiding the source.
Odontocete behavioral criteria for non-impulsive sources were
updated based on controlled exposure studies for dolphins and sea
mammals, sonar, and safety (3S) studies where odontocete behavioral
responses were reported after exposure to sonar (Miller et al., 2011;
Miller et al., 2012; Antunes et al., 2014; Miller et al., 2014; Houser
et al., 2013b). For the 3S study, the sonar outputs included 1-2 kHz
up- and down-sweeps and 6-7 kHz up-sweeps; source levels were ramped up
from 152-158 dB re 1 [mu]Pa to a maximum of 198-214 re 1 [mu]Pa at 1 m.
Sonar signals were ramped up over several pings while the vessel
approached the mammals. The study did include some control passes of
ships with the sonar off to discern the behavioral responses of the
mammals to vessel presence alone versus active sonar.
The controlled exposure studies included exposing the Navy's
trained bottlenose dolphins to mid-frequency sonar while they were in a
pen. Mid-frequency sonar was played at six different exposure levels
from 125-185 dB re 1 [mu]Pa (RMS). The behavioral response function for
odontocetes resulting from the studies described above has a 50 percent
probability of response at 157 dB re 1 [mu]Pa. Additionally, distance
cutoffs (20 km for MF cetaceans) were applied to exclude exposures
beyond which the potential of significant behavioral responses is
considered to be unlikely.
The pinniped behavioral threshold was updated based on controlled
exposure experiments on the following captive animals: hooded seal
(Cystophora cristata), gray seal (Halichoerus grypus), and California
sea lion (G[ouml]tz et al., 2010; Houser et al., 2013a; Kvadsheim et
al., 2010). Hooded seals were exposed to increasing levels of sonar
until an avoidance response was observed, while the grey seals were
exposed first to a single received level multiple times, then an
increasing received level. Each individual California sea lion was
exposed to the same received level ten times. These exposure sessions
were combined into a single response value, with an overall response
assumed if an animal responded in any single session. The resulting
behavioral response function for pinnipeds has a 50 percent probability
of response at 166 dB re 1
[[Page 66084]]
[mu]Pa. Additionally, distance cutoffs (10 km for pinnipeds) were
applied to exclude exposures beyond which the potential of significant
behavioral responses is considered unlikely. For additional information
regarding marine mammal thresholds for PTS and TTS onset, please see
NMFS (2018) and table 6.
Empirical evidence has not shown responses to non-impulsive
acoustic sources that would constitute take beyond a few km from a non-
impulsive acoustic source, which is why NMFS and the Navy
conservatively set distance cutoffs for pinnipeds and mid-frequency
cetaceans (U.S. Department of the Navy, 2017a). The cutoff distances
for fixed sources are different from those for moving sources, as they
are treated as individual sources in ONR's modeling given that the
distance between them is significantly greater than the range to which
environmental effects can occur. Fixed source cutoff distances used
were 5 km (2.7 nm) for pinnipeds and 10 km (5.4 nm) for beluga whales
(table 5). As some of the on-site drifting sources could come closer
together, the drifting source cutoffs applied were 10 km (5.4 nm) for
pinnipeds and 20 km (10.8 nm) for beluga whales (table 5). Regardless
of the received level at that distance, take is not estimated to occur
beyond these cutoff distances. Range to thresholds were calculated for
the noise associated with icebreaking in the study area. These all fall
within the same cutoff distances as non-impulsive acoustic sources;
range to behavioral threshold for both beluga whales and ringed seal
were under 5 km (2.7 nm), and range to TTS threshold for both under 15
m (49.2 ft) (table 5).
Table 5--Cutoff Distances and Acoustic Thresholds Identifying the Onset of Behavioral Disturbance, TTS, and PTS for Non-Impulsive Sound Sources
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Fixed source Drifting source Behavioral Icebreaking source Behavioral
behavioral behavioral criteria: Non- behavioral criteria: Physiological Physiological
Hearing group Species threshold cutoff threshold cutoff impulsive acoustic threshold cutoff icebreaking criteria: onset criteria: onset
distance \a\ distance \a\ sources distance \a b\ sources TTS PTS
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-frequency cetaceans......... Beluga whale...... 10 km (5.4 nm).... 20 km (10.8 nm)... Mid-frequency BRF 5 km (2.7 nm)..... 120 dB re 1 178 dB SELcum..... 198 dB SELcum.
dose-response [micro]Pa step
function *. function.
Phocidae (in water)............. Ringed seal....... 5 km (2.7 nm)..... 10 km (5.4 nm).... Pinniped dose- 5 km (2.7 nm)..... 120 dB re 1 181 dB SELcum..... 201 dB SELcum.
response function [micro]Pa step
*. function.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Note: The threshold values provided are assumed for when the source is within the animal's best hearing sensitivity. The exact threshold varies based on the overlap of the source and the
frequency weighting (see figure 6-1 in IHA application).
\a\ Take is not estimated to occur beyond these cutoff distances, regardless of the received level.
\b\ Range to TTS threshold for both hearing groups for the noise associated with icebreaking in the Study Area is under 15 m (49.2 ft).
Level A Harassment
NMFS' Technical Guidance for Assessing the Effects of Anthropogenic
Sound on Marine Mammal Hearing (Version 2.0) (Technical Guidance, 2018)
identifies dual criteria to assess auditory injury (Level A harassment)
to five different marine mammal groups (based on hearing sensitivity)
as a result of exposure to noise from two different types of sources
(impulsive or non-impulsive). The ONR's proposed action includes the
use of non-impulsive (active sonar and icebreaking) sources; however,
Level A harassment is not expected as a result of the proposed
activities based on modeling, as described below, nor is it proposed to
be authorized by NMFS.
These thresholds are provided in the table below. The references,
analysis, and methodology used in the development of the thresholds are
described in NMFS' 2018 Technical Guidance, which may be accessed at:
https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
Table 6--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
PTS onset acoustic thresholds * (received level)
Hearing group ------------------------------------------------------------------------
Impulsive Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans........... Cell 1: Lpk,flat: 219 dB; Cell 2: LE,LF,24h: 199 dB.
LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans........... Cell 3: Lpk,flat: 230 dB; Cell 4: LE,MF,24h: 198 dB.
LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans.......... Cell 5: Lpk,flat: 202 dB; Cell 6: LE,HF,24h: 173 dB.
LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater)..... Cell 7: Lpk,flat: 218 dB; Cell 8: LE,PW,24h: 201 dB.
LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater).... Cell 9: Lpk,flat: 232 dB; Cell 10: LE,OW,24h: 219 dB.
LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
a reference value of 1 [mu]Pa\2\s. In this table, thresholds are abbreviated to reflect American National
Standards Institute (ANSI) standards. However, peak sound pressure is defined by ANSI as incorporating
frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is
being included to indicate peak sound pressure should be flat weighted or unweighted within the generalized
hearing range. The subscript associated with cumulative sound exposure level thresholds indicates the
designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and
that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be
exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it
is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
exceeded.
[[Page 66085]]
Quantitative Modeling
The Navy performed a quantitative analysis to estimate the number
of marine mammals likely to be exposed to underwater acoustic
transmissions above the previously described threshold criteria during
the proposed action. Inputs to the quantitative analysis included
marine mammal density estimates obtained from the Kaschner et al.
(2006) habitat suitability model and (Ca[ntilde]adas et al., 2020),
marine mammal depth occurrence (U.S. Department of the Navy, 2017b),
oceanographic and mammal hearing data, and criteria and thresholds for
levels of potential effects. The quantitative analysis consists of
computer modeled estimates and a post-model analysis to determine the
number of potential animal exposures. The model calculates sound energy
propagation from the proposed non-impulsive acoustic sources, the sound
received by animat (virtual animal) dosimeters representing marine
mammals distributed in the area around the modeled activity, and
whether the sound received by animats exceeds the thresholds for
effects.
The Navy developed a set of software tools and compiled data for
estimating acoustic effects on marine mammals without consideration of
behavioral avoidance or mitigation. These tools and data sets serve as
integral components of the Navy Acoustic Effects Model (NAEMO). In
NAEMO, animats are distributed non-uniformly based on species-specific
density, depth distribution, and group size information and animats
record energy received at their location in the water column. A fully
three-dimensional environment is used for calculating sound propagation
and animat exposure in NAEMO. Site-specific bathymetry, sound speed
profiles, wind speed, and bottom properties are incorporated into the
propagation modeling process. NAEMO calculates the likely propagation
for various levels of energy (sound or pressure) resulting from each
source used during the training event.
NAEMO then records the energy received by each animat within the
energy footprint of the event and calculates the number of animats
having received levels of energy exposures that fall within defined
impact thresholds. Predicted effects on the animats within a scenario
are then tallied and the highest order effect (based on severity of
criteria; e.g., PTS over TTS) predicted for a given animat is assumed.
Each scenario, or each 24-hour period for scenarios lasting greater
than 24 hours is independent of all others, and therefore, the same
individual marine mammal (as represented by an animat in the model
environment) could be impacted during each independent scenario or 24-
hour period. In few instances, although the activities themselves all
occur within the proposed study location, sound may propagate beyond
the boundary of the study area. Any exposures occurring outside the
boundary of the study area are counted as if they occurred within the
study area boundary. NAEMO provides the initial estimated impacts on
marine species with a static horizontal distribution (i.e., animats in
the model environment do not move horizontally).
There are limitations to the data used in the acoustic effects
model, and the results must be interpreted within this context. While
the best available data and appropriate input assumptions have been
used in the modeling, when there is a lack of definitive data to
support an aspect of the modeling, conservative modeling assumptions
have been chosen (i.e., assumptions that may result in an overestimate
of acoustic exposures):
Animats are modeled as being underwater, stationary, and
facing the source and therefore always predicted to receive the maximum
potential sound level at a given location (i.e., no porpoising or
pinnipeds' heads above water);
Animats do not move horizontally (but change their
position vertically within the water column), which may overestimate
physiological effects such as hearing loss, especially for slow moving
or stationary sound sources in the model;
Animats are stationary horizontally and therefore do not
avoid the sound source, unlike in the wild where animals would most
often avoid exposures at higher sound levels, especially those
exposures that may result in PTS;
Multiple exposures within any 24-hour period are
considered one continuous exposure for the purposes of calculating
potential threshold shift, because there are not sufficient data to
estimate a hearing recovery function for the time between exposures;
and
Mitigation measures were not considered in the model. In
reality, sound-producing activities would be reduced, stopped, or
delayed if marine mammals are detected by visual monitoring.
Due to these inherent model limitations and simplifications, model-
estimated results should be further analyzed, considering such factors
as the range to specific effects, avoidance, and the likelihood of
successfully implementing mitigation measures. This analysis uses a
number of factors in addition to the acoustic model results to predict
acoustic effects on marine mammals, as described below in the Marine
Mammal Occurrence and Take Estimation section.
The underwater radiated noise signature for icebreaking in the
central Arctic Ocean by CGC HEALY during different types of ice-cover
was characterized in Roth et al. (2013). The radiated noise signatures
were characterized for various fractions of ice cover. For modeling,
the 8/10 and 3/10 ice cover were used. Each modeled day of icebreaking
consisted of 16 hours of 8/10 ice cover and 8 hours of 3/10 ice cover.
The sound signature of the 5/10 icebreaking activities, which would
correspond to half-power icebreaking, was not reported in Roth et al.
(2013); therefore, the full-power signature was used as a conservative
proxy for the half-power signature. Icebreaking was modeled for 8 days
total. Since ice forecasting cannot be predicted more than a few weeks
in advance, it is unknown if icebreaking would be needed to deploy or
retrieve the sources after 1 year of transmitting. Therefore, the
potential for an icebreaking cruise on CGC HEALY was conservatively
analyzed within the ONR's request for an IHA. As the R/V Sikuliaq is
not capable of icebreaking, acoustic noise created by icebreaking is
only modeled for the CGC HEALY. Figures 5a and 5b in Roth et al. (2013)
depict the source spectrum level versus frequency for 8/10 and 3/10 ice
cover, respectively. The sound signature of each of the ice coverage
levels was broken into 1-octave bins (table 7). In the model, each bin
was included as a separate source on the modeled vessel. When these
independent sources go active concurrently, they simulate the sound
signature of CGC HEALY. The modeled source level summed across these
bins was 196.2 dB for the 8/10 signature and 189.3 dB for the 3/10 ice
signature. These source levels are a good approximation of the
icebreaker's observed source level (provided in figure 4b of Roth et
al. (2013). Each frequency and source level was modeled as an
independent source, and applied simultaneously to all of the animats
within NAEMO. Each second was summed across frequency to estimate
SPLRMS. Any animat exposed to sound levels greater than 120
dB was considered a take by Level B harassment. For PTS and TTS,
determinations, sound exposure levels were summed over the duration of
the
[[Page 66086]]
test and the transit to the deep water deployment area. The method of
quantitative modeling for icebreaking is considered to be a
conservative approach; therefore, the number of takes estimated for
icebreaking are likely an overestimate and would not be expected to
reach that level.
Table 7--Modeled Bins for 8/10 Ice Coverage (Full Power) and 3/10 Ice
Coverage (Quarter Power) Icebreaking on CGC HEALY
------------------------------------------------------------------------
8/10 source 3/10 source
Frequency (Hz) level (dB) level (dB)
------------------------------------------------------------------------
25............................................ 189 187
50............................................ 188 182
100........................................... 189 179
200........................................... 190 177
400........................................... 188 175
800........................................... 183 170
1,600......................................... 177 166
3,200......................................... 176 171
6,400......................................... 172 168
12,800........................................ 167 164
------------------------------------------------------------------------
Non-Impulsive Acoustic Analysis
Most likely, individuals affected by acoustic transmission would
move away from the sound source. Ringed seals may be temporarily
displaced from their subnivean lairs in the winter, but a pinniped
would have to be within 5 km (2.7 nm) of a moored source or within 10
km (5.4 nm) of a drifting source for any behavioral reaction. Any
effects experienced by individual pinnipeds are anticipated to be
short-term disturbance of normal behavior, or temporary displacement or
disruption of animals that may be near elements of the proposed action.
Of historical sightings registered in the Ocean Biodiversity
Information System Spatial Ecological Analysis of Megavertebrate
Populations (OBIS-SEAMAP database) (Halpin et al., 2009) in the ARA
Study Area, nearly all (99 percent) occurred in summer and fall
seasons. However, there is no documentation to prove that this is
because ringed seals would all move out of the Study Area during the
cold season, or if the lack of sightings is due to the harsh
environment and ringed seal behavior being prohibitive factors for cold
season surveying. OBIS-SEAMAP reports 542 animals sighted over 150
records in the ARA Study Area across all years and seasons. Taking the
average of 542 animals in 150 records aligns with survey data from
previous ARA cruises that show up to three ringed seals (or small,
unidentified pinnipeds assumed to be ringed seals) per day sighted in
the Study Area. To account for any unsighted animals, that number was
rounded up to 4. Assuming that four animals would be present in the
Study Area, a rough estimate of density can be calculated using the
overall Study Area size:
4 ringed seals / 48,725 km\2\ = 0.00008209 ringed seals/km\2\
The area of influence surrounding each moored source would be 78.5
km\2\, and the area of influence surrounding each drifting source would
be 314 km\2\. The total area of influence on any given day from non-
impulsive acoustic sources would be 942 km\2\. The number of ringed
seals that could be taken daily can be calculated:
0.00008209 ringed seals/km\2\ x 942 km\2\ = 0.077 ringed seals/day
To be conservative, the ONR has assumed that one ringed seal would
be exposed to acoustic transmissions above the threshold for Level B
harassment, and that each would be exposed each day of the proposed
action (365 days total). Unlike the NAEMO modeling approach used to
estimate ringed seal takes in previous ARA IHAs, the occurrence method
used in this ARA IHA request does not support the differentiation
between behavioral or TTS exposures. Therefore, all takes are
classified as Level B harassment and not further distinguished.
Modeling for all previous years of ARA activities did not result in any
estimated Level A harassment. NMFS has no reason to expect that the ARA
activities during the effective dates of this IHA would be more likely
to result in Level A harassment. Therefore, no Level A harassment is
anticipated due to the proposed action.
Marine Mammal Occurrence and Take Estimation
In this section we provide information about the occurrence of
marine mammals, including density or other relevant information which
will inform the take calculations. We also describe how the marine
mammal occurrence information is synthesized to produce a quantitative
estimate of the take that is reasonably likely to occur and proposed
for authorization.
The beluga whale density numbers utilized for quantitative acoustic
modeling are from the Navy Marine Species Density Database (U.S.
Department of the Navy, 2014). Where available (i.e., June through 15
October over the continental shelf primarily), density estimates used
were from Duke density modeling based upon line-transect surveys
(Ca[ntilde]adas et al., 2020). The remaining seasons and geographic
area were based on the habitat-based modeling by Kaschner (2004) and
Kaschner et al. (2006). Density for beluga whales was not distinguished
by stock and varied throughout the project area geographically and
monthly; the range of densities in the Study Area is shown in table 8.
The density estimates for ringed seals are based on the habitat
suitability modeling by Kaschner (2004) and Kaschner et al. (2006) and
shown in table 8.
Table 8--Density Estimates of Impacted Species
------------------------------------------------------------------------
Common name Stock Density (animals/km\2\)
------------------------------------------------------------------------
Beluga whale................. Beaufort Sea.... 0.000506 to 0.5176
Beluga whale................. Eastern Chukchi 0.000506 to 0.5176
Sea.
Ringed seal.................. Arctic.......... 0.1108 to 0.3562
------------------------------------------------------------------------
Take of all species would occur by Level B harassment only. NAEMO
was previously used to produce a qualitative estimate of PTS, TTS, and
behavioral exposures for ringed seals. For this proposed action, a new
approach that utilizes sighting data from previous surveys conducted
within the Study Area was used to estimate Level B harassment
associated with non-impulsive acoustic sources (see section 6.4.3 of
the IHA application). NAEMO modeling is still used to provide estimated
takes of beluga whales associated with non-impulsive acoustic sources,
as well as provide take estimations associated with icebreaking for
both species. Table 9 shows the total number of requested takes by
Level B harassment that NMFS proposes to authorize for both beluga
whale stocks and the Arctic ringed seal stock based upon NAEMO modeled
results.
[[Page 66087]]
Density estimates for beluga whales are equal as estimates were not
distinguished by stock (Kaschner, 2004; Kaschner et al., 2006). The
ranges of the Beaufort Sea and Eastern Chukchi Sea beluga whales vary
within the study area throughout the year (Hauser et al., 2014). Based
upon the limited information available regarding the expected spatial
distributions of each stock within the study area, take has been
apportioned equally to each stock (table 9). In addition, in NAEMO,
animats do not move horizontally or react in any way to avoid sound,
therefore, the current model may overestimate non-impulsive acoustic
impacts.
Table 9--Proposed Take by Level B Harassment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Active Icebreaking Icebreaking Total proposed Percentage of
Species Stock acoustics (behavioral) (TTS) take SAR abundance population
--------------------------------------------------------------------------------------------------------------------------------------------------------
Beluga whale...................... Beaufort Sea........ \a\ 177 \a\ 21 0 99 39,258 <1
Beluga whale...................... Chukchi Sea......... \a\ 177 \a\ 21 0 99 13,305 <1
Ringed seal....................... Arctic.............. 365 538 1 904 \b\ UND (171, <1
418)
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Acoustic and icebreaking exposures to beluga whales were not modeled at the stock level as the density value is not distinguished by stock in the
Arctic for beluga whales (U.S. Department of the Navy, 2014). Estimated take of beluga whales due to active acoustics is 177 and 21 due to icebreaking
activities, totaling 198 takes of beluga whales. The total take was evenly distributed among the two stocks.
\b\ A reliable population estimate for the entire Arctic stock of ringed seals is not available and NMFS SAR lists it as Undetermined (UND). Using a sub-
sample of data collected from the U.S. portion of the Bering Sea (Conn et al., 2014), an abundance estimate of 171,418 ringed seals has been
calculated but this estimate does not account for availability bias due to seals in the water or in the shore-fast ice zone at the time of the survey.
The actual number of ringed seals in the U.S. portion of the Bering Sea is likely much higher. Using the minimum population size (Nmin = 158,507)
based upon this negatively biased population estimate, the PBR is calculated to be 4,755 seals, although this is also a negatively biased estimate.
Proposed Mitigation
In order to issue an IHA under section 101(a)(5)(D) of the MMPA,
NMFS must set forth the permissible methods of taking pursuant to the
activity, and other means of effecting the least practicable impact on
the species or stock and its habitat, paying particular attention to
rookeries, mating grounds, and areas of similar significance, and on
the availability of the species or stock for taking for certain
subsistence uses. NMFS regulations require applicants for incidental
take authorizations to include information about the availability and
feasibility (economic and technological) of equipment, methods, and
manner of conducting the activity or other means of effecting the least
practicable adverse impact upon the affected species or stocks, and
their habitat (50 CFR 216.104(a)(11)). The 2004 NDAA amended the MMPA
as it relates to military readiness activities and the incidental take
authorization process such that ``least practicable impact'' shall
include consideration of personnel safety, practicality of
implementation, and impact on the effectiveness of the military
readiness activity.
In evaluating how mitigation may or may not be appropriate to
ensure the least practicable adverse impact on species or stocks and
their habitat, as well as subsistence uses where applicable, NMFS
considers two primary factors:
(1) The manner in which, and the degree to which, the successful
implementation of the measure(s) is expected to reduce impacts to
marine mammals, marine mammal species or stocks, and their habitat, as
well as subsistence uses. This considers the nature of the potential
adverse impact being mitigated (likelihood, scope, range). It further
considers the likelihood that the measure will be effective if
implemented (probability of accomplishing the mitigating result if
implemented as planned), the likelihood of effective implementation
(probability implemented as planned), and;
(2) The practicability of the measures for applicant
implementation, which may consider such things as cost, impact on
operations, and, in the case of a military readiness activity,
personnel safety, practicality of implementation, and impact on the
effectiveness of the military readiness activity.
The following measures are proposed for this IHA:
All vessels operated by or for the Navy must have
personnel assigned to stand watch at all times while underway. Watch
personnel must employ visual search techniques using binoculars. While
underway and while using active acoustic sources/towed in-water
devices, at least one person with access to binoculars is required to
be on watch at all times.
Vessel captains and vessel personnel must remain alert at
all times, proceed with extreme caution, and operate at a safe speed so
that the vessel can take proper and effective action to avoid any
collisions with marine mammals.
During moored and drifting acoustic source deployment and
recovery, ONR must implement a mitigation zone of 55 m (180 ft) around
the deployed source. Deployment and recovery must cease if a marine
mammal is visually deterred within the mitigation zone. Deployment and
recovery may recommence if any one of the following conditions are met:
[cir] The animal is observed exiting the mitigation zone;
[cir] The animal is thought to have exited the mitigation zone
based on a determination of its course, speed, and movement relative to
the sound source;
[cir] The mitigation zone has been clear from any additional
sightings for a period of 15 minutes for pinnipeds and 30 minutes for
cetaceans.
Vessels must avoid approaching marine mammals head-on and
must maneuver to maintain a mitigation zone of 457 m (500 yards) around
all observed cetaceans and 183 m (200 yards) around all other observed
marine mammals, provided it is safe to do so.
Activities must cease if a marine mammal species for which
take was not authorized, or a species for which authorization was
granted but the authorized number of takes have been met, is observed
approaching or within the mitigation zone (table 10). Activities must
not resume until the animal is confirmed to have left the area.
Vessel captains must maintain at-sea communication with
subsistence hunters to avoid conflict of vessel transit with hunting
activity.
Table 10--Proposed Mitigation Zones
------------------------------------------------------------------------
Activity and/or effort type Species Mitigation zone
------------------------------------------------------------------------
Acoustic source deployment and Beluga whale...... 55 m (180 ft).
recovery, stationary.
[[Page 66088]]
Acoustic source deployment and Ringed seal....... 55 m (180 ft).
recovery, stationary.
Transit......................... Beluga whale...... 457 m (500 yards).
Transit......................... Ringed seal....... 183 m (200 yards).
------------------------------------------------------------------------
Based on our evaluation of the applicant's proposed measures, NMFS
has preliminarily determined that the proposed mitigation measures
provide the means of effecting the least practicable impact on the
affected species or stocks and their habitat, paying particular
attention to rookeries, mating grounds, areas of similar significance,
and on the availability of such species or stock for subsistence uses.
Proposed Monitoring and Reporting
In order to issue an IHA for an activity, section 101(a)(5)(D) of
the MMPA states that NMFS must set forth requirements pertaining to the
monitoring and reporting of such taking. The MMPA implementing
regulations at 50 CFR 216.104(a)(13) indicate that requests for
authorizations must include the suggested means of accomplishing the
necessary monitoring and reporting that will result in increased
knowledge of the species and of the level of taking or impacts on
populations of marine mammals that are expected to be present while
conducting the activities. Effective reporting is critical both to
compliance as well as ensuring that the most value is obtained from the
required monitoring.
Monitoring and reporting requirements prescribed by NMFS should
contribute to improved understanding of one or more of the following:
Occurrence of marine mammal species or stocks in the area
in which take is anticipated (e.g., presence, abundance, distribution,
density);
Nature, scope, or context of likely marine mammal exposure
to potential stressors/impacts (individual or cumulative, acute or
chronic), through better understanding of: (1) action or environment
(e.g., source characterization, propagation, ambient noise); (2)
affected species (e.g., life history, dive patterns); (3) co-occurrence
of marine mammal species with the activity; or (4) biological or
behavioral context of exposure (e.g., age, calving or feeding areas);
Individual marine mammal responses (behavioral or
physiological) to acoustic stressors (acute, chronic, or cumulative),
other stressors, or cumulative impacts from multiple stressors;
How anticipated responses to stressors impact either: (1)
long-term fitness and survival of individual marine mammals; or (2)
populations, species, or stocks;
Effects on marine mammal habitat (e.g., marine mammal prey
species, acoustic habitat, or other important physical components of
marine mammal habitat); and,
Mitigation and monitoring effectiveness.
The Navy has coordinated with NMFS to develop an overarching
program plan in which specific monitoring would occur. This plan is
called the Integrated Comprehensive Monitoring Program (ICMP) (U.S.
Department of the Navy, 2011). The ICMP has been developed in direct
response to Navy permitting requirements established through various
environmental compliance efforts. As a framework document, the ICMP
applies by regulation to those activities on ranges and operating areas
for which the Navy is seeking or has sought incidental take
authorizations. The ICMP is intended to coordinate monitoring efforts
across all regions and to allocate the most appropriate level and type
of effort based on a set of standardized research goals, and in
acknowledgement of regional scientific value and resource availability.
The ICMP is focused on Navy training and testing ranges where the
majority of Navy activities occur regularly as those areas have the
greatest potential for being impacted. ONR's ARA in comparison is a
less intensive test with little human activity present in the Arctic.
Human presence is limited to the deployment of sources that would take
place over several weeks. Additionally, due to the location and nature
of the testing, vessels and personnel would not be within the study
area for an extended period of time. As such, more extensive monitoring
requirements beyond the basic information being collected would not be
feasible as it would require additional personnel and equipment to
locate seals and a presence in the Arctic during a period of time other
then what is planned for source deployment. However, ONR will record
all observations of marine mammals, including the marine mammal's
species identification, location (latitude/longitude), behavior, and
distance from project activities. ONR will also record date and time of
sighting. This information is valuable in an area with few recorded
observations.
Marine mammal monitoring must be conducted in accordance with the
Navy's ICMP and the proposed IHA:
While underway, all vessels must have at least one person
trained through the U.S. Navy Marine Species Awareness Training Program
on watch during all activities;
Watch personnel must use standardized data collection
forms, whether hard copy or electronic. Watch personnel must
distinguish between sightings that occur during transit or during
deployment or recovery of acoustic sources. Data must be recorded on
all days of activities, even if marine mammals are not sighted;
At minimum, the following information must be recorded:
[cir] Vessel name;
[cir] Watch personnel names and affiliation;
[cir] Effort type (i.e., transit, deployment, recovery); and
[cir] Environmental conditions (at the beginning of watch stander
shift and whenever conditions change significantly), including Beaufort
Sea State (BSS) and any other relevant weather conditions, including
cloud cover, fog, sun glare, and overall visibility to the horizon.
Upon visual observation of any marine mammal, the
following information must be recorded:
[cir] Date/time of sighting;
[cir] Identification of animal (e.g., genus/species, lowest
possible taxonomic level, or unidentified) and the composition of the
group if there is a mix of species;
[cir] Location (latitude/longitude) of sighting;
[cir] Estimated number of animals (high/low/best);
[cir] Description (as many distinguishing features as possible of
each individual seen, including length, shape, color, pattern, scars or
markings, shape and size of dorsal fin, shape of head, and blow
characteristics);
[cir] Detailed behavior observations (e.g., number of blows/
breaths, number of surfaces, breaching, spyhopping,
[[Page 66089]]
diving, feeding, traveling; as explicit and detailed as possible;
length of time observed in the mitigation zone, note any observed
changes in behavior);
[cir] Distance from vessel to animal;
[cir] Direction of animal's travel relative to the vessel;
[cir] Platform activity at time of sighting (i.e., transit,
deployment, recovery); and
[cir] Weather conditions (i.e., BSS, cloud cover).
[cir] During icebreaking, the following information must be
recorded:
[cir] Start and end time of icebreaking; and
[cir] Ice cover conditions.
During deployment and recovery of acoustic sources or
UUVs, visual observation must begin 30 minutes prior to deployment or
recovery and continue through 30 minutes following the source
deployment or recovery.
The ONR must submit its draft report(s) on all monitoring
conducted under the IHA within 90 calendar days of the completion of
monitoring or 60 calendar days prior to the requested issuance of any
subsequent IHA for research activities at the same location, whichever
comes first. A final report must be prepared and submitted within 30
calendar days following receipt of any NMFS comments on the draft
report. If no comments are received from NMFS within 30 calendar days
of receipt of the draft report, the report shall be considered final.
All draft and final monitoring reports must be submitted
to [email protected] and [email protected].
The marine mammal report, at minimum, must include:
[cir] Dates and times (begin and end) of all marine mammal
monitoring;
[cir] Acoustic source use or icebreaking;
[cir] Watch stander location(s) during marine mammal monitoring;
[cir] Environmental conditions during monitoring periods (at
beginning and end of watch standing shift and whenever conditions
change significantly), including BSS and any other relevant weather
conditions including cloud cover, fog, sun glare, and overall
visibility to the horizon, and estimated observable distance;
[cir] Upon observation of a marine mammal, the following
information:
[ssquf] Name of watch stander who sighted the animal(s), the watch
stander location, and activity at time of sighting;
[ssquf] Time of sighting;
[ssquf] Identification of the animal(s) (e.g., genus/species,
lowest possible taxonomic level, or unidentified), watch stander
confidence in identification, and the composition of the group if there
is a mix of species;
[ssquf] Distance and location of each observed marine mammal
relative to the acoustic source or icebreaking for each sighting;
[ssquf] Estimated number of animals (min/max/best estimate);
[ssquf] Estimated number of animals by cohort (adults, juveniles,
neonates, group composition, etc.);
[ssquf] Animal's closest point of approach and estimated time spent
within the harassment zone; and
[ssquf] Description of any marine mammal behavioral observations
(e.g., observed behaviors such as feeding or traveling), including an
assessment of behavioral responses thought to have resulted from the
activity (e.g., no response or changes in behavioral state such as
ceasing feeding, changing direction, flushing, or breaching.
[cir] Number of shutdowns during monitoring, if any;
[cir] Marine mammal sightings (including the marine mammal's
location (latitude/longitude));
[cir] Number of individuals of each species observed during source
deployment, operation, and recovery; and
[cir] Detailed information about implementation of any mitigation
(e.g., shutdowns, delays), a description of specific actions that
ensued, and resulting changes in behavior of the animal(s), if any.
The ONR must submit all watch stander data electronically
in a format that can be queried, such as a spreadsheet or database
(i.e., digital images of data sheets are not sufficient).
Reporting injured or dead marine mammals:
[cir] In the event that personnel involved in the specified
activities discover an injured or dead marine mammal, the ONR must
report the incident to the Office of Protected Resources (OPR), NMFS
([email protected] and [email protected]) and to
the Alaska regional stranding network (877-925-7773) as soon as
feasible. If the death or injury was clearly caused by the specified
activity, the ONR must immediately cease the activities until NMFS OPR
is able to review the circumstances of the incident and determine what,
if any, additional measures are appropriate to ensure compliance with
the terms of this IHA. The ONR must not resume their activities until
notified by NMFS.
[cir] The report must include the following information:
[ssquf] Time, date, and location (latitude/longitude) of the first
discovery (and updated location information if known and applicable);
[ssquf] Species identification (if known) or description of the
animal(s) involved;
[ssquf] Condition of the animal(s) (including carcass condition if
the animal is dead);
[ssquf] Observed behaviors of the animal(s), if alive;
[ssquf] If available, photographs or video footage of the
animal(s); and
[ssquf] General circumstances under which the animal was
discovered.
Vessel Strike: In the event of a vessel strike of a marine
mammal by any vessel involved in the activities covered by the
authorization, the ONR shall report the incident to OPR, NMFS and to
the Alaska regional stranding coordinator (877-925-7773) as soon as
feasible. The report must include the following information:
[cir] Time, date, and location (latitude/longitude) of the
incident;
[cir] Species identification (if known) or description of the
animal(s) involved;
[cir] Vessel's speed during and leading up to the incident;
[cir] Vessel's course/heading and what operations were being
conducted (if applicable);
[cir] Status of all sound sources in use;
[cir] Description of avoidance measures/requirements that were in
place at the time of the strike and what additional measures were
taken, if any, to avoid strike;
[cir] Environmental conditions (e.g., wind speed and direction,
BSS, cloud cover, visibility) immediately preceding the strike;
[cir] Estimated size and length of animal that was struck;
[cir] Description of the behavior of the marine mammal immediately
preceding and following the strike;
[cir] If available, description of the presence and behavior of any
other marine mammals immediately preceding the strike;
[cir] Estimated fate of the animal (e.g., dead, injured but alive,
injured and moving, blood or tissue observed in the water, status
unknown, disappeared); and
[cir] To the extent practicable, photographs or video footage of
the animal(s).
Negligible Impact Analysis and Determination
NMFS has defined negligible impact as an impact resulting from the
specified activity that cannot be reasonably expected to, and is not
reasonably likely to, adversely affect the species or stock through
effects on annual rates of recruitment or survival (50 CFR 216.103). A
negligible impact finding is based on the lack of likely adverse
effects on annual rates of
[[Page 66090]]
recruitment or survival (i.e., population-level effects). An estimate
of the number of takes alone is not enough information on which to base
an impact determination. In addition to considering estimates of the
number of marine mammals that might be ``taken'' through harassment,
NMFS considers other factors, such as the likely nature of any impacts
or responses (e.g., intensity, duration), the context of any impacts or
responses (e.g., critical reproductive time or location, foraging
impacts affecting energetics), as well as effects on habitat, and the
likely effectiveness of the mitigation. We also assess the number,
intensity, and context of estimated takes by evaluating this
information relative to population status. Consistent with the 1989
preamble for NMFS' implementing regulations (54 FR 40338, September 29,
1989), the impacts from other past and ongoing anthropogenic activities
are incorporated into this analysis via their impacts on the baseline
(e.g., as reflected in the regulatory status of the species, population
size and growth rate where known, ongoing sources of human-caused
mortality, or ambient noise levels).
To avoid repetition, the discussion of our analysis applies to
beluga whales and ringed seals, given that the anticipated effects of
this activity on these different marine mammal stocks are expected to
be similar. Where there are meaningful differences between species or
stocks, or groups of species, in anticipated individual responses to
activities, impact of expected take on the population due to
differences in population status, or impacts on habitat, they are
described independently in the analysis below.
Underwater acoustic transmissions associated with the proposed ARA,
as outlined previously, have the potential to result in Level B
harassment of beluga seals and ringed seals in the form of behavioral
disturbances. No serious injury, mortality, or Level A harassment are
anticipated to result from these described activities. Effects on
individual belugas or ringed seals taken by Level B harassment could
include alteration of dive behavior and/or foraging behavior, effects
to breathing rates, interference with or alteration of vocalization,
avoidance, and flight. More severe behavioral responses are not
anticipated due to the localized, intermittent use of active acoustic
sources. Exposure duration is likely to be short-term and individuals
will, most likely, simply be temporarily displaced by moving away from
the acoustic source. Exposures are, therefore, unlikely to result in
any significant realized decrease in fitness for affected individuals
or adverse impacts to stocks as a whole.
Arctic ringed seals are listed as threatened under the ESA. The
primary concern for Arctic ringed seals is the ongoing and anticipated
loss of sea ice and snow cover resulting from climate change, which is
expected to pose a significant threat to ringed seals in the future
(Muto et al., 2021). In addition, Arctic ringed seals have also been
experiencing a UME since 2019 although the cause of the UME is
currently undetermined. As mentioned earlier, no mortality or serious
injury to ringed seals is anticipated nor proposed to be authorized.
Due to the short-term duration of expected exposures and required
mitigation measures to reduce adverse impacts, we do not expect the
proposed ARA to compound or exacerbate the impacts of the ongoing UME.
A small portion of the Study Area overlaps with ringed seal
critical habitat. Although this habitat contains features necessary for
ringed seal formation and maintenance of subnivean birth lairs, basking
and molting, and foraging, these features are also available throughout
the rest of the designated critical habitat area. Any potential limited
displacement of ringed seals from the proposed ARA study area would not
be expected to interfere with their ability to access necessary habitat
features, given the availability of similar necessary habitat features
nearby.
The Study Area also overlaps with beluga whale migratory and
feeding BIAs. Due to the small amount of overlap between the BIAs and
the proposed ARA study area as well as the low intensity and short-term
duration of acoustic sources and required mitigation measures, we
expect minimal impacts to migrating or feeding belugas. Shutdown zones
are expected to avoid the potential for Level A harassment of belugas
and ringed seals, and to minimize the severity of any Level B
harassment. The requirements of trained dedicated watch personnel and
speed restrictions will also reduce the likelihood of any ship strikes
to migrating belugas.
In all, the proposed activities are expected to have minimal
adverse effects on marine mammal habitat. While the activities may
cause some fish to leave the area of disturbance, temporarily impacting
marine mammals' foraging opportunities, this would encompass a
relatively small area of habitat leaving large areas of existing fish
and marine mammal foraging habitat unaffected. As such, the impacts to
marine mammal habitat are not expected to impact the health or fitness
of any marine mammals.
In summary and as described above, the following factors primarily
support our preliminary determination that the impacts resulting from
this activity are not expected to adversely affect any of the species
or stocks through effects on annual rates of recruitment or survival:
No serious injury or mortality is anticipated or
authorized;
Impacts would be limited to Level B harassment only;
Only temporary and relatively low-level behavioral
disturbances are expected to result from these proposed activities; and
Impacts to marine mammal prey or habitat will be minimal
and short term.
The anticipated and authorized take is not expected to impact the
reproduction or survival of any individual marine mammals, much less
rates of recruitment or survival. Based on the analysis contained
herein of the likely effects of the specified activity on marine
mammals and their habitat, and taking into consideration the
implementation of the proposed monitoring and mitigation measures, NMFS
preliminarily finds that the total marine mammal take from the proposed
activity will have a negligible impact on all affected marine mammal
species or stocks.
Unmitigable Adverse Impact Analysis and Determination
In order to issue an IHA, NMFS must find that the specified
activity will not have an ``unmitigable adverse impact'' on the
subsistence uses of the affected marine mammal species or stocks by
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50
CFR 216.103 as an impact resulting from the specified activity: (1)
That is likely to reduce the availability of the species to a level
insufficient for a harvest to meet subsistence needs by: (i) Causing
the marine mammals to abandon or avoid hunting areas; (ii) Directly
displacing subsistence users; or (iii) Placing physical barriers
between the marine mammals and the subsistence hunters; and (2) That
cannot be sufficiently mitigated by other measures to increase the
availability of marine mammals to allow subsistence needs to be met.
Subsistence hunting is important for many Alaska Native
communities. A study of the North Slope villages of Nuiqsut, Kaktovik,
and Utqia[gdot]vik identified the primary resources used for
subsistence and the locations for harvest (Stephen R. Braund &
Associates, 2010), including terrestrial mammals, birds, fish, and
marine mammals (bowhead whale, ringed seal,
[[Page 66091]]
bearded seal, and walrus). Ringed seals and beluga whales are likely
located within the project area during this proposed action, yet the
proposed action would not remove individuals from the population nor
behaviorally disturb them in a manner that would affect their behavior
more than 100 km farther inshore where subsistence hunting occurs. The
permitted sources would be placed far outside of the range for
subsistence hunting. The closest active acoustic source (fixed or
drifting) within the proposed project site that is likely to cause
Level B harassment is approximately 204 km (110 nm) from land. This
ensures a significant standoff distance from any subsistence hunting
area. The closest distance to subsistence hunting (130 km (70 nm)) is
well beyond the largest distance from the sound sources in use at which
behavioral harassment would be expected to occur (20 km (10.8 nm))
described above. Furthermore, there is no reason to believe that any
behavioral disturbance of beluga whales or ringed seals that occurs far
offshore (we do not anticipate any Level A harassment) would affect
their subsequent behavior in a manner that would interfere with
subsistence uses should those animals later interact with hunters.
In addition, ONR has been communicating with the Native communities
about the proposed action. The ONR-sponsored chief scientist for AMOS
gave a briefing on ONR research planned for 2024-2025 Alaska Eskimo
Whaling Commission (AEWC) meeting on December 15, 2023 in Anchorage,
Alaska. No questions were asked from the commissioners during the brief
or in subsequent weeks afterwards. The AEWC consists of representatives
from 11 whaling villages (Wainwright, Utqia[gdot]vik, Savoonga, Point
Lay, Nuiqut, Kivalina, Kaktovik, Wales, Point Hope, Little Diomede, and
Gambell). These briefings have communicated the lack of any effect on
subsistence hunting due to the distance of the sources from hunting
areas. ONR-supported scientists also attend Arctic Waterways Safety
Committee (AWSC) and AEWC meetings on a regular basis to discuss past,
present, and future research activities. While no take is anticipated
to result during transit, points of contact for at-sea communication
will also be established between vessel captains and subsistence
hunters to avoid any conflict of ship transit with hunting activity.
Based on the description of the specified activity, distance of the
study area from subsistence hunting grounds, the measures described to
minimize adverse effects on the availability of marine mammals for
subsistence purposes, and the proposed mitigation and monitoring
measures, NMFS has preliminarily determined that there will not be an
unmitigable adverse impact on subsistence uses from ONR's proposed
activities.
Peer Review of the Monitoring Plan
The MMPA requires that monitoring plans be independently peer
reviewed where the proposed activity may affect the availability of a
species or stock for taking for subsistence uses (16 U.S.C.
1371(a)(5)(D)(ii)(III)). Given the factors discussed above, NMFS has
also determined that the activity is not likely to affect the
availability of any marine mammal species or stock for taking for
subsistence uses, and therefore, peer review of the monitoring plan is
not warranted for this project.
Endangered Species Act
Section 7(a)(2) of the ESA of 1973 (16 U.S.C. 1531 et seq.)
requires that each Federal agency insure that any action it authorizes,
funds, or carries out is not likely to jeopardize the continued
existence of any endangered or threatened species or result in the
destruction or adverse modification of designated critical habitat. To
ensure ESA compliance for the issuance of IHAs, NMFS consults
internally whenever we propose to authorize take for endangered or
threatened species, in this case with the Alaska Regional Office (AKR).
NMFS is proposing to authorize take of ringed seals, which are
listed under the ESA. The Permits and Conservation Division has
requested initiation of section 7 consultation with the AKR for the
issuance of this IHA. NMFS will conclude the ESA consultation prior to
reaching a determination regarding the proposed issuance of the
authorization.
Proposed Authorization
As a result of these preliminary determinations, NMFS proposes to
issue an IHA to the ONR for conducting a seventh year of ARA in the
Beaufort and Chukchi Seas from September 2024 to September 2025,
provided the previously mentioned mitigation, monitoring, and reporting
requirements are incorporated. A draft of the proposed IHA can be found
at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-military-readiness-activities.
Request for Public Comments
We request comment on our analyses, the proposed authorization, and
any other aspect of this notice of proposed IHA for the proposed ARA.
We also request comment on the potential renewal of this proposed IHA
as described in the paragraph below. Please include with your comments
any supporting data or literature citations to help inform decisions on
the request for this IHA or a subsequent renewal IHA.
On a case-by-case basis, NMFS may issue a one-time, 1-year renewal
IHA following notice to the public providing an additional 15 days for
public comments when (1) up to another year of identical or nearly
identical activities as described in the Description of Proposed
Activity section of this notice is planned or (2) the activities as
described in the Description of Proposed Activity section of this
notice would not be completed by the time the IHA expires and a renewal
would allow for completion of the activities beyond that described in
the Dates and Duration section of this notice, provided all of the
following conditions are met:
A request for renewal is received no later than 60 days
prior to the needed renewal IHA effective date (recognizing that the
renewal IHA expiration date cannot extend beyond 1 year from expiration
of the initial IHA).
The request for renewal must include the following:
(1) An explanation that the activities to be conducted under the
requested renewal IHA are identical to the activities analyzed under
the initial IHA, are a subset of the activities, or include changes so
minor (e.g., reduction in pile size) that the changes do not affect the
previous analyses, mitigation and monitoring requirements, or take
estimates (with the exception of reducing the type or amount of take).
(2) A preliminary monitoring report showing the results of the
required monitoring to date and an explanation showing that the
monitoring results do not indicate impacts of a scale or nature not
previously analyzed or authorized.
Upon review of the request for renewal, the status of the
affected species or stocks, and any other pertinent information, NMFS
determines that there are no more than minor changes in the activities,
the mitigation and monitoring measures will remain the same and
appropriate, and the findings in the initial IHA remain valid.
Dated: August 8, 2024.
Kimberly Damon-Randall,
Director, Office of Protected Resources, National Marine Fisheries
Service.
[FR Doc. 2024-18130 Filed 8-13-24; 8:45 am]
BILLING CODE 3510-22-P