[Federal Register Volume 87, Number 89 (Monday, May 9, 2022)]
[Notices]
[Pages 27597-27624]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-09916]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB882]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Tugs Towing Drill Rig in Cook 
Inlet, Alaska

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

ACTION: Notice; proposed incidental harassment authorizations; request 
for comments on proposed authorizations.

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SUMMARY: NMFS has received a request from Hilcorp Alaska LLC (Hilcorp) 
for authorization to take marine mammals incidental to tugboats towing 
a drill rig in Cook Inlet, Alaska. Pursuant to the Marine Mammal 
Protection Act (MMPA), NMFS is requesting comments on its proposal to 
issue two successive incidental harassment authorizations (IHAs) to 
incidentally take marine mammals during the specified activities. NMFS 
is also requesting comments on a possible one-time, one-year renewal 
that could be issued under certain circumstances and if all 
requirements are met, as described in Request for Public Comments at 
the end of this notice. NMFS will consider public comments prior to 
making any final decision on the issuance of the requested MMPA 
authorizations and agency responses will be summarized in the final 
notice of our decision.

DATES: Comments and information must be received no later than June 8, 
2022.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief,

[[Page 27598]]

Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Written comments should be submitted 
via email to <a href="/cdn-cgi/l/email-protection#4f061b1f6116203a21280f21202e2e61282039"><span class="__cf_email__" data-cfemail="f3baa7a3ddaa9c869d94b39d9c9292dd949c85">[email protected]</span></a>.
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at 
www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Sara Young, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. In case of problems accessing these 
documents, please call the contact listed above.

SUPPLEMENTARY INFORMATION: 

Background

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

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review its proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment. 
Accordingly, NMFS is preparing an Environmental Assessment (EA) to 
consider the environmental impacts associated with the issuance of the 
proposed IHAs. NMFS' EA will be made available at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act at the time of publication. 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 requests.

Summary of Request

    On January 13, 2022, NMFS received a request from Hilcorp for two 
IHAs to take marine mammals incidental to tugs towing a drill rig in 
Cook Inlet, Alaska. The application was deemed adequate and complete on 
March 8, 2022. Hilcorp's request is for take of small numbers of eleven 
species of marine mammals by Level B harassment only. Neither Hilcorp 
nor NMFS expects serious injury or mortality to result from this 
activity and, therefore, an IHA is appropriate.
    NMFS previously issued Incidental Take Regulations (ITRs) to 
Hilcorp for a suite of oil and gas activities in Cook Inlet, Alaska (84 
FR 37442; July 31, 2019) and issued three letters of authorization 
(LOAs) under those ITRs. The ITRs covered activities including: Two-
dimensional (2D) and three-dimensional (3D) seismic surveys, geohazard 
surveys, vibratory sheet pile driving, and drilling of exploratory 
wells. On September 17, 2019, Cook Inletkeeper and the Center for 
Biological Diversity filed suit in the District of Alaska challenging 
NMFS's issuance of the ITRs and LOAs and supporting documents (the EA 
and Endangered Species Act (ESA) Biological Opinion). In a decision 
issued on March 30, 2021, the court ruled largely in NMFS's favor, but 
found a lack of adequate support in NMFS's record for the agency's 
determination that tug towing of drill rigs in connection with 
production activity will not cause take of beluga whales and remanded 
back to NMFS for further analysis of tug use under the MMPA, ESA, and 
NEPA. Hilcorp notified NMFS that all activities described in their 
initial ITR application (2018) and for which incidental take was 
authorized have already been completed or will not be completed in the 
remaining effective period of the ITRs. As a result, the only remaining 
activity to be analyzed is the use of tugs towing a jack-up rig. NMFS 
proposes to authorize incidental take from the tugs towing a jack-up 
rig through two sequential IHAs as the appropriate mechanism, given 
that there are no more activities occurring under the ITRs, no serious 
injury or mortality is expected, and Hilcorp's timing needs.

Description of Proposed Activity

Overview

    Hilcorp Alaska, LLC (Hilcorp) plans to carry out activities that 
will occur over two separate one-year periods--from April 1, 2022 to 
March 31, 2023 (Year 1) and from April 1, 2023 to March 31, 2024 (Year 
2). Hilcorp plans to use three ocean-going tugs to tow a jack-up rig in 
support of plugging and abandonment (P&A) of an existing well and to 
support production drilling at other locations in middle Cook Inlet and 
Trading Bay over the course of two years.

Dates and Duration

    The schedule for Hilcorp's P&A and production drilling activities 
is provided in Table 1 below. The noise-producing rig-towing activities 
for which take is proposed would occur in between those activities, for 
approximately 16 days per year for Year 1 and Year 2.

[[Page 27599]]



                        Table 1--Dates and Durations of Planned Activities in Cook Inlet
----------------------------------------------------------------------------------------------------------------
                                                                                                    Duration of
             Project type                 Cook inlet region                  Timing                 activity *
                                                                                                      (days)
----------------------------------------------------------------------------------------------------------------
Year 1:
    Plug and Abandonment of Well       Middle Cook Inlet......  April-November..................              30
     17589.
    Production Drilling..............  Middle Cook Inlet        April-November..................             180
                                        Trading Bay.
Year 2:
    Production Drilling..............  Middle Cook Inlet        April-November..................             180
                                        Trading Bay.
----------------------------------------------------------------------------------------------------------------
* Duration is in reference to the supported activity that requires the jack-up rig to be in a specific location.
  It is not reflective of the duration or the number of days the jack-up rig is towed.

Specific Geographic Region

    Hilcorp's proposed activities would take place in Cook Inlet, 
Alaska. For the purposes of this project, lower Cook Inlet refers to 
waters south of the East and West Forelands; middle Cook Inlet refers 
to waters north of the East and West Forelands and south of Threemile 
River on the west and Point Possession on the east; Trading Bay refers 
to waters from approximately the Granite Point Tank Farm on the north 
to the West Foreland on the south; and upper Cook Inlet refers to 
waters north and east of Beluga River on the west and Point Possession 
on the east. A map of the specific area in which Hilcorp plans to 
operate is provided in Figure 1 below.
BILLING CODE 3510-22-P

[[Page 27600]]

[GRAPHIC] [TIFF OMITTED] TN09MY22.030

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    Hilcorp proposes to use three tugs to pull and position a jack-up 
rig in support of well plugging and abandonment (P&A) and support of 
production drilling by using the rig as a temporary drilling platform. 
Hilcorp proposes to use the jack-up rig Spartan 151, or similar. A 
jack-up rig is a type of mobile offshore drill unit used in offshore 
oil and gas drilling activities. It is comprised of a buoyant mobile 
platform or hull with moveable legs that are adjusted to raise and 
lower the hull over the surface of the water. The Spartan 151 (or 
similar) will be towed via three ocean-going tugs. The horsepower (hp) 
of each of the three tugs used to tow the jack-up rig may range between 
4,000 and 8,000. Three tugs are needed to safely and effectively pull 
the jack-up rig into the correct position where it can be temporarily 
secured to the seafloor. Specifications of the tugs anticipated for use 
are provided in Table 2 below. If these specific tugs are not 
available, the tugs contracted would be of similar size and power to 
those listed in Table 2.

[[Page 27601]]



           Table 2--Description of Tugs Towing the Jack-Up Rig
------------------------------------------------------------------------
                Vessel name                        Specifications
------------------------------------------------------------------------
M/V Bering Wind...........................  22-m length x 10-m breadth,
                                             144 gross tonnage
M/V Anna T................................  32-m length x 11-m breadth,
                                             160 gross tonnage
M/V Bob Franco............................  37-m length x 11-m breadth,
                                             196 gross tonnage
------------------------------------------------------------------------

    The amount of time the tugs are under load transiting, holding, and 
positioning the jack-up rig in Cook Inlet is tide-dependent. The power 
output of the tugs depends on whether the tugs are towing with or 
against the tide and can vary across a tide cycle as the current 
increases or decreases in speed over time. Hilcorp proposes to make 
every effort to transit with the tide (which requires lower power 
output) and minimize transit against the tide (which requires higher 
power output).
    The jack-up rig will be mobilized and demobilized via towing by 
three ocean-going tugs from and to the Rig Tenders Dock in Nikiski, 
Alaska. A high slack tide is necessary for the tugs to approach close 
enough to shore to attach and mobilize the jack-up rig from the Rig 
Tenders Dock. Because Hilcorp's production platforms/well sites are 
north of the initial mobilization site, the tugs will begin their 
transit from Nikiski against an outgoing tide. To minimize transit time 
against the outgoing tide and reduce power output, the tugs will first 
tow the jack-up rig to a location near the Offshore Systems Kenai dock 
for approximately three hours, which provides protection from the fast 
outgoing tidal current. Protection from the outgoing tidal current will 
allow the tugs to expend less power holding the jack-up rig in position 
than they would if they continued to transit against the tide. The tugs 
will begin transiting north again when the tide changes to an incoming 
tide, which is about six hours after the high slack tide. Towing the 
jack-up rig northward with an incoming tide requires less than half 
power, generally only 20 to 30 percent of total power output (Durham 
2021, pers. comm.).
    A high slack tide is preferred to position the jack-up rig on an 
existing platform or well site. The relatively slow current and calm 
conditions at a slack tide enables the tugs to perform the fine 
movements necessary to safely position the jack-up rig within several 
feet of the platform. Positioning and securing the jack-up rig is 
generally performed at high slack tide rather than low slack tide to 
pin the legs down at an adequate height to ensure the hull of the jack-
up rig remains above the water level of the subsequent incoming high 
tide. Because 12 hours elapse between each high slack tide, tugs are 
generally under load for those 12 hours, even if the towed distance is 
small, as high slack tides are preferred to both attach and detach the 
jack-up rig from the tugs. Once the tugs are on location with the jack-
up rig at high slack tide (12 hours from the previous departure), there 
is a 1 to 2-hour window when the tide is slow enough for the tugs to 
initiate positioning the jack-up rig and pin the legs to the seafloor 
on location. The tugs are estimated to be under load, generally at 
half-power conditions or less, for up to 14 hours from the time of 
departure through the initial positioning attempt of the jack-up rig. 
If the first positioning attempt takes longer than anticipated, the 
increasing current speed prevents the tugs from safely positioning the 
jack-up rig on location. If the first positioning attempt is not 
successful, the jack-up rig will be pinned down at a nearby location 
and the tugs will be released from the jack-up rig and no longer under 
load. The tugs will remain nearby, generally floating with the current. 
Approximately an hour before the next high slack tide, the tugs will 
re-attach to the jack-up rig and reattempt positioning over a period of 
2 to 3 hours. Positioning activities are generally at half power. If a 
third attempt is needed, the tugs would be under load holding or 
positioning the jack-up rig on a second day for up to 5 hours. The vast 
majority of the time, the jack-up rig can be successfully positioned 
over the platform in one or two attempts.
    A location-to-location transport (e.g., platform-to-platform) of a 
jack-up rig is conducted similarly to the mobilization from the Rig 
Tenders Dock described above with one main difference. In a location-
to-location transport in middle Cook Inlet or Trading Bay, there is no 
harbor available for temporary staging to avoid transiting against the 
tide. Maintaining position of the jack-up rig against the tidal current 
can require more than half power (up to 90 percent power at the peak 
tidal outflow). However, greater than half power effort is only needed 
for short periods of time during the maximum tidal current, expected to 
be no more than three hours maximum. During a location-to-location 
transport, the tugs will transport the jack-up rig traveling with the 
tide in nearly all circumstances except in situations that threaten the 
safety of humans and/or infrastructure integrity. There may be a 
situation wherein the tugs pulling the jack-up rig begin transiting 
with the tide to their next location, miss the tide window to safely 
set the jack-up rig on the platform or pin it nearby, and so have to 
transport the jack-up rig against the tide to a safe harbor. Tugs may 
also need to transport the jack-up rig against the tide if large pieces 
of ice or extreme wind events threaten the stability of the jack-up rig 
on the platform.
    Although the variability in power output from the tugs can range 
from an estimated 20 percent to 90 percent throughout the hours under 
load with the jack-up rig, as described above, the majority of the 
hours (spent transiting, holding, and positioning) occur at half power 
or less. See the Estimated Take section below for more detail on 
assumptions related to power output.
    Year 1--For the first year of activity, Hilcorp proposes use of 
three tugs to pull the jack-up rig for plugging and abandonment (P&A) 
of Well 17589, which began in 2021 but was not completed due to 
equipment sourcing issues. Prior to pinning the jack-up rig legs to the 
seafloor, a multi-beam sonar may be used to ensure the seafloor is 
clear of debris that may impact the ability to pin down the legs of the 
platform. The multibeam echosounder emits high frequency (240 kilohertz 
[kHz]) energy in a fan-shaped pattern of equidistant or equiangular 
beam spacing. The multi-beam sonar operates at a frequency outside of 
marine mammal hearing range and is not addressed further in our 
analysis. After the rig is secure, divers enter the water and use hand 
tools to complete the P&A process. In addition to the hand tools, the 
divers will also use water jets to wash away debris and marine growth 
on the structure (e.g., a CaviDyne CaviBlaster). Based on measurements 
conducted by Hilcorp during 2017 use of water jets, the source level 
for the CaviBlaster[supreg] was estimated as 176 decibels (dB) re 1 
micropascal ([mu]Pa) root mean square (rms) with a Level B harassment 
threshold of 860 m, with most energy concentrated above 500 Hz with a 
dominant tone near 2 kHz. Hilcorp plans to put a protected species 
observer (PSO) on watch to monitor the full extent of the harassment 
zone and shutdown when an animal approaches the zone during water jet 
use. Because of this, Hilcorp is not requesting take associated with 
water jet use and it is not considered further in our analysis.
    Hilcorp also plans to tug the jack-up rig to existing platforms in 
middle Cook Inlet and Trading Bay in support of production drilling 
activities from existing platforms and wellbores. Production drilling 
itself creates some small level of noise due to the use of

[[Page 27602]]

generators and other potentially noise-generating equipment. Furie 
Operating Alaska, LLC, performed detailed underwater acoustic 
measurements in the vicinity of the Spartan 151 in 2011 (Marine 
Acoustics Inc. 2011) northeast of Nikiski Bay in water depths of 24.4 
to 27.4 m (80 to 90 ft). Primary sources of rig-based acoustic energy 
were identified as coming from the D399/D398 diesel engines, the PZ-10 
mud pump, ventilation fans, and electrical generators. The source level 
of one of the loudest acoustic sources, the diesel engines, was 
estimated to be 137 dB re 1 [mu]Pa rms at 1 m in the 141 to 178 Hz 
frequency range. Based on this measured level, the 120 dB rms acoustic 
received level isopleth would be approximately 50 m away from where the 
energy enters the water (jack-up leg or drill riser). This small radius 
would overlap substantially with the physical footprint of the platform 
and other equipment, so Hilcorp is not requesting take for this 
activity and it is not considered further in our analysis. In support 
of these activities, helicopters and support vessels transit from the 
mainland to the production sites to mobilize personnel and supplies. 
Helicopters will fly at 1,500 ft or higher unless human safety is at 
risk or it is operationally impossible (e.g., takeoff and landing 
points are so close together the aircraft cannot reach 1,500 ft). 
Vessel trips to and from the location of the jack-up rig are expected 
to increase by two trips per day above normal activity levels.
    Year 2--For the second year of activity, Hilcorp does not plan to 
conduct P&A activities with the jack-up rig and will only be tugging 
the jack-up rig in support of production drilling activities.
    The specific configuration of tugs towing the jack-up-rig as 
proposed by Hilcorp has not been analyzed previously. Hilcorp 
contracted JASCO Applied Sciences to conduct a sound source 
verification (SSV) of their tugs in operation in Cook Inlet during 
October 2021. This SSC measured tugs pulling the jack-up-rig at various 
power outputs. This SSV returned a source level of a source level of 
167.3 dB re 1 [mu]Pa for the 20 percent power scenario and a source 
level of 205.9 dB re 1 [mu]Pa for the 85 percent power scenario. 
Assuming a linear scaling of tug power, a source level of 185 dB re 1 
[mu]Pa was then calculated as a single point source level for three 
tugs operating at 50% power output. This is approximately five dB 
higher than the literature summary described below.
    Hilcorp conducted a literature review of available source level 
data for tugs under load in varying power output scenarios. Table 3 
below provides values of measured source levels for tugs varying from 
2,000 to 8,2000 horsepower. For the purposes of this table, berthing 
activities could include tugs either pushing or pulling a load. The 
sound source levels appear correlated to speed and power output, with 
full power output and higher speeds generating more propeller 
cavitation and greater sound source levels than lower power output and 
lower speeds. Additional tug source levels are available from the 
literature but they are not specific to tugs under load but rather 
measured values for tugs during activities such as transiting, docking, 
and anchor pulling. For a summary of these additional tug values, see 
Table 7 in Hilcorp's application.

                                                Table 3--Literature Values of Measured Tug Source Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                          Source level
              Vessel                Vessel length  Speed  (knots)        Activity         @1 m  (re: 1     Horsepower               Reference
                                         (m)                                               [micro]Pa)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Eagle............................              32             9.6  Towing barge........             173           6,770  Bassett et al. 2012.
Valor............................              30             8.4  Towing barge........             168           2,400
Lela Joy.........................              24             4.9  Towing barge........             172           2,000
Pacific Eagle....................              28             8.2  Towing barge........             165           2,000
Shannon..........................              30             9.3  Towing barge........             171           2,000
James T Quigg....................              30             7.9  Towing barge........             167           2,000
Island Scout.....................              30             5.8  Towing barge........             174           4,800
Chief............................              34            11.4  Towing barge........             174           8,200
Lauren Foss......................              45             N/A  Berthing barge......             167           8,200  Austin et al. 2013.
Seaspan Resolution...............              30             N/A  Berthing at half                 180           6,000  Roberts Bank Terminal 2
                                                                    power.                                                Technical Report 2014.
Seaspan Resolution...............              30             N/A  Berthing at full                 200           6,000
                                                                    power.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The Roberts Bank Terminal 2 Technical Report (2014), although not 
in Cook Inlet, includes repeated measurements of the same tug operating 
under different speeds and loads. This allows for a comparison of 
source levels from the same vessel at half power versus full power, 
which is an important distinction for Hilcorp's activities, as a small 
fraction of the total time spent by tugs under load will be at greater 
than 50 percent power. The Seaspan Resolution's half-power berthing 
scenario has a sound source level of 180 dB re 1 [mu]Pa at 1 m. In 
addition, the Roberts Bank Report (2014) analyzed 650 tug transits 
under varying load and speed conditions and reported mean tug source 
levels of 179.3 dB re 1 [mu]Pa at 1 m, the 25th percentile was 179.0 dB 
re 1 [mu]Pa at 1 m, and 5th percentile source levels were 184.9 dB re 1 
[mu]Pa at 1 m.
    Based solely on the literature review, a source level of 180 dB for 
a tug under load would be appropriate. However, Hilcorp's use of a 
three tug configuration would increase the literature source level to 
approximately 185dB. As one or two tugs are primarily under load, the 
third tug sits off to the side. NMFS still considers these tugs to be 
simultaneous sources. When considered in conjunction with the 
additional tugs present in the configuration as well as the SSV 
conducted by JASCO for Hilcorp's specific configuration, a source level 
of 185 dB for tugs towing a jack-up rig was carried forward for 
analysis.
    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. 
Additional information

[[Page 27603]]

regarding population trends and threats may be found in NMFS's Stock 
Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more 
general information about these species (e.g., physical and behavioral 
descriptions) may be found on NMFS's website (https://www.fisheries.noaa.gov/find-species).
    Table 4 lists all species or stocks for which take is expected and 
proposed to be authorized for this action, and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. For taxonomy, we follow the Committee on 
Taxonomy (2021). PBR is defined by the MMPA as the maximum number of 
animals, not including natural mortalities, that may be removed from a 
marine mammal stock while allowing that stock to reach or maintain its 
optimum sustainable population (as described in NMFS's SARs). While no 
mortality is anticipated or authorized here, PBR and annual serious 
injury and mortality from anthropogenic sources are included here as 
gross indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. 2020 SARs (e.g., Muto et al. 2021). All values presented in 
Table 4 are the most recent available at the time of publication and 
are available in the 2020 SARs (Muto et al. 2021) and draft 2021 SARs 
(available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                            Table 4--Marine Mammal Species or Stocks for Which Take Is Expected and Proposed To Be Authorized
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        ESA/MMPA  status;    Stock abundance  (CV,
             Common name                  Scientific name               Stock            strategic  (Y/N)      Nmin, most recent       PBR     Annual  M/
                                                                                               \1\           abundance survey) \2\               SI \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray whale......................  Eschrichtius robustus..  Eastern Pacific.......  -, -, N              26,960 (0.05, 25,849,         801        131
                                                                                                             2016).
Family Balaenidae:
    Humpback whale..................  Megaptera novaeangliae.  Western North Pacific.  E, D, Y              1,107 (0.3, 865, 2006)          3        2.8
    Minke whale.....................  Balaenoptera             Alaska................  -, -, N              N/A (see SAR, N/A, see        UND          0
                                       acutorostrata.                                                        SAR).
Family Balaenopteridae (rorquals):
    Fin whale.......................  Balaenoptera physalus..  Northeastern Pacific..  E, D, Y              see SAR (see SAR, see     see SAR        0.6
                                                                                                             SAR, 2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Beluga whale....................  Delphinapterus leucas..  Cook Inlet............  E, D, Y              279 (0.061, 267, 2018)    see SAR          0
    Killer whale....................  Orcinus orca...........  Alaska Resident.......  -, -, N              2,347 c (N/A, 2347,            24          1
                                                                                                             2012).
    Killer whale....................  Orcinus orca...........  Gulf of Alaska,         -, -, N              587 c (N/A, 587, 2012)       5.87        0.8
                                                                Aleutian Islands, and
                                                                Bering Sea Transient.
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena phocoena......  Gulf of Alaska........  -, -, Y              31,046 (0.21, N/A,            UND         72
                                                                                                             1998).
    Dall's porpoise.................  Phocoenoides dalli.....  Alaska................  -, -, N              see SAR (0.097, see       see SAR         37
                                                                                                             SAR, 2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion................  Eumetopias jubatus.....  Western...............  E, D, Y              52,932 a (see SAR,            318        254
                                                                                                             52,932, 2019).
    California sea lion.............  Zalophus californianus.  U.S...................  -, -, N              257,606 (N/A,233,515,       14011       >320
                                                                                                             2014).
Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina.........  Cook Inlet/Shelikof...  -, -, N              28,411 (see SAR,              807        107
                                                                                                             26,907, 2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable depending on the methodology described in the stock assessment report (SAR) and the date of last
  available survey data. Where necessary, NMFS refers reader to the SAR for more detail.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual mortality and serious injury often cannot be determined precisely and is in some cases presented as a
  minimum value or range.


[[Page 27604]]

    As indicated above, all 11 species (with 12 managed stocks) in 
Table 4 temporally and spatially co-occur with the activity to the 
degree that take could reasonably occur, and we have proposed 
authorizing it. In addition, the northern sea otter may be found in 
Cook Inlet, Alaska. However, sea otters are managed by the U.S. Fish 
and Wildlife Service and are not considered further in this document.

Gray Whale

    The eastern North Pacific stock of gray whales occurring in Cook 
Inlet are likely migrating to summer feeding grounds in the Bering, 
Chukchi, and Beaufort seas, although some whales are known to feed near 
Kodiak Island (Carretta et al. 2014). Gray whales generally breed every 
two years during November and December while undertaking the southern 
migration (Jones and Swartz 2009). Gray whales have been reported 
feeding near Kodiak Island, in southeastern Alaska, and south along the 
Pacific Northwest (Allen and Angliss 2013). Most gray whales migrating 
through the Gulf of Alaska region are thought to take a coastal route 
and (Ferguson et al. 2015) delineated the migratory corridor 
biologically important area (BIA) boundaries based on the extent of the 
continental shelf.
    Most gray whales calve and breed from late December to early 
February in protected waters along the western coast of Baja 
California, Mexico. In spring, the Eastern North Pacific stock of gray 
whales migrates ~8,000 km (5,000 mi) to feeding grounds in the Bering 
and Chukchi seas before returning to their wintering areas in the fall 
(Rice and Wolman 1971). Northward migration, primarily of individuals 
without calves, begins in February; some cow/calf pairs delay their 
departure from the calving area until well into April (Jones and Swartz 
1984). Gray whales approach the lower Cook Inlet in late March, April, 
May, and June, and leave again in November and December (Consiglieri et 
al. 1982; Rice and Wolman 1971) but migrate past the mouth of Cook 
Inlet to and from northern feeding grounds. Some gray whales do not 
migrate completely from Baja to the Chukchi Sea but instead feed in 
select coastal areas in the Pacific Northwest, including lower Cook 
Inlet (Moore et al. 2007).
    Most of the population follows the outer coast of the Kodiak 
Archipelago from the Kenai Peninsula in spring or the Alaska Peninsula 
in fall (Consiglieri et al. 1982; Rice and Wolman 1971). Though most 
gray whales migrate past Cook Inlet, small numbers have been noted by 
fishers near Kachemak Bay, and north of Anchor Point (BOEM 2015). 
During the NMFS aerial surveys, gray whales were observed in the month 
of June in 1994, 2000, 2001, 2005 and 2009 on the east side of Cook 
Inlet near Port Graham and Elizabeth Island but also on the west side 
near Kamishak Bay (Shelden et al. 2013). One gray whale was sighted as 
far north at the Beluga River. Additionally, summering gray whales were 
seen offshore of Cape Starichkof by marine mammal observers monitoring 
Buccaneer's Cosmopolitan drilling program in 2013 (Owl Ridge 2014). 
During Apache's 2012 seismic program, nine gray whales were observed in 
June and July (Lomac-MacNair et al. 2013). During Apache's seismic 
program in 2014, one gray whale was observed (Lomac-MacNair et al. 
2014). During SAExploration's seismic survey in 2015, no gray whales 
were observed (Kendall et al. 2015). No gray whales were observed 
during the 2019 Hilcorp seismic survey in lower Cook Inlet (Fairweather 
Science 2020) or during the 2018 Cook Inlet Pipeline (CIPL) project 
(Sitkiewicz et al. 2018).

Humpback Whale

    Humpback whales are found throughout southern Alaska in a variety 
of marine environments, including open-ocean, near-shore waters, and 
areas with strong tidal currents (Dahlheim et al. 2009). Most humpback 
whales are migratory and spend winters in the breeding grounds off 
either Hawaii or Mexico. Humpback whales are regularly present and 
feeding in Cook Inlet in the summer. Current threats to humpback whales 
include vessel strikes, spills, climate change, and commercial fishing 
operations (Muto et al. 2021).
    Humpback whales worldwide were designated as ``endangered'' under 
the Endangered Species Conservation Act in 1970, and were listed under 
the ESA at its inception in 1973. However, on September 8, 2016, NMFS 
published a final decision that changed the status of humpback whales 
under the ESA (81 FR 62259), effective October 11, 2016. The decision 
recognized the existence of 14 distinct population segments (DPSs) 
based on distinct breeding areas in tropical and temperate waters. Five 
of the 14 DPSs were classified under the ESA (4 endangered and 1 
threatened), while the other 9 DPSs were delisted. Humpback whales 
found in the project area are predominantly members of the Hawaii DPS, 
which is not listed under the ESA. However, based on analyses of photo-
identification studies in Alaska, members of the Mexico DPS and the 
Western North Pacific DPS, which are listed as threatened and 
endangered respectively, are thought to occur in Cook Inlet. 
Approximately one percent of all humpback whales in Cook Inlet are 
thought to belong to the endangered Western North Pacific DPS and 11 
percent are thought to belong to the threatened Mexico DPS. All other 
humpback whales present are thought to belong to the non-listed Hawaii 
DPS (Wade et al. 2021). Members of different DPSs are known to intermix 
on feeding grounds; therefore, all waters off the coast of Alaska 
should be considered to have ESA-listed humpback whales. Critical 
habitat was recently designated near the entrance of lower Cook Inlet 
for Western North Pacific DPS and Mexico DPS humpback whales (86 FR 
21082; April 21, 2021); however, Hilcorp's action area does not 
spatially overlap with any critical habitat designated for humpback 
whale DPS.
    The DPSs of humpback whales that were identified through the ESA 
listing process do not necessarily equate to the existing MMPA stocks. 
The stock delineations of humpback whales under the MMPA are currently 
under review. Until this review is complete, NMFS considers humpback 
whales in Cook Inlet to be part of the Central North Pacific stock, 
with a status of endangered under the ESA and designations of strategic 
and depleted under the MMPA (Muto et al. 2021).
    In the summer, humpback whales are regularly present and feeding in 
the Cook Inlet region, including Shelikof Strait, Kodiak Island bays, 
and the Barren Islands, in addition to Gulf of Alaska regions adjacent 
to the southeast side of Kodiak Island (especially Albatross Banks), 
the Kenai and Alaska peninsulas, Elizabeth Island, as well as south of 
the Aleutian Islands. Humpbacks also may be present in some of these 
areas throughout autumn (Muto et al. 2017).
    Humpback whales have been observed during marine mammal surveys 
conducted in Cook Inlet; however, their presence is largely confined to 
lower Cook Inlet. During SAExploration's 2015 seismic program, three 
humpback whales were observed in Cook Inlet; two near the Forelands and 
one in Kachemak Bay (Kendall et al. 2015). During NMFS Cook Inlet 
beluga whale aerial surveys from 2000 to 2018, there were 88 sightings 
of 191 estimated individual humpback whales in lower Cook Inlet 
(Shelden et al. 2017). They have been regularly seen near Kachemak Bay 
during the summer months (Rugh et al. 2005). There are observations of 
humpback whales as far north as Anchor Point, with recent summer 
observations extending to Cape Starichkof (Owl Ridge 2014). Several

[[Page 27605]]

humpback whale sightings occurred lower Cook Inlet between Iniskin 
Peninsula and Kachemak Bay near Augustine, Barren, and Elizabeth 
Islands (Shelden et al. 2013, 2015, 2017). There were two sightings of 
three humpback whales observed near Ladd Landing north of the Forelands 
on the recent Harvest Alaska Cook Inlet Pipeline Extension (CIPL) 
project (Sitkiewicz et al. 2018). There were 14 sightings of 38 
humpback whales observed in the 2019 Hilcorp lower Cook Inlet seismic 
survey in the fall (Fairweather Science 2020). This higher number of 
humpback whales was expected in the lower Cook Inlet region than 
Hilcorp's proposed work in the late summer/fall period.
    Ferguson et al. (2015) identified a biologically important area 
(BIA), in which humpback whales are known to concentrate for feeding, 
in the Gulf of Alaska region. The BIA encompasses the waters east of 
Kodiak Island (the Albatross and Portlock Banks), a target for 
historical commercial whalers based out of Port Hobron, Alaska 
(Ferguson et al. 2015; Reeves et al. 1985; Witteveen et al. 2007). This 
BIA also includes waters along the southeastern side of Shelikof Strait 
and in the bays along the northwestern shore of Kodiak Island. The 
highest densities of humpback whales around the Kodiak Island BIA occur 
from July-August (Ferguson et al. 2015). This BIA lies directly south 
but does not spatially overlap with Hilcorp's proposed action area.

Minke Whale

    Minke whales are a non-ESA listed cetacean not commonly found in 
the Cook Inlet region. Minke whales are not designated as depleted 
under the MMPA or listed as threatened or endangered under the ESA. 
Presumably, minke whales breed in warm, low latitude waters during 
winter, give birth every other year to one calf, and reach sexual 
maturity at 7 to 9 m (23 to 30 ft) in length (Perrin and Brownell 
2009). Potential threats to and vulnerabilities of minke whales include 
anthropogenic sound emissions underwater, impacts on prey distribution, 
climate change, fishing operations, vessel strikes, and oil and gas 
operations (Muto et al. 2018).
    Minke whales are most abundant in the Gulf of Alaska during summer 
and occupy localized feeding areas (Zerbini et al. 2006). 
Concentrations of minke whales have occurred along the north coast of 
Kodiak Island and along the south coast of the Alaska Peninsula 
(Zerbini et al. 2006). The most recent estimate for minke whales 
specifically between Kenai Fjords and the Aleutian Islands is 1,233 
individuals (Zerbini et al. 2006). No population estimate for minke 
whales in the entirety of the north Pacific exists (Muto et al, 2019). 
During shipboard surveys conducted in 2003, three minke whale sightings 
were made, all near the eastern extent of the survey from nearshore 
Prince William Sound to the shelf break (MML, 2003). Minke whales 
become scarce in the Gulf of Alaska in fall; most whales are thought to 
leave the region by October (Consiglieri et al. 1982). Minke whales are 
migratory in Alaska, but recently have been observed off Cape 
Starichkof and Anchor Point year-round (Muto et al. 2017).
    During Cook Inlet-wide aerial surveys conducted from 1993 to 2004, 
minke whales were encountered three times (1998, 1999, and 2006), both 
times off Anchor Point 26 km (16 miles [mi]) northwest of Homer 
(Shelden et al. 2013, 2015, 2017; Shelden and Wade 2019). A minke whale 
was also reported off Cape Starichkof in 2011 and 2013, suggesting this 
location is regularly used by minke whales, including during the 
winter. Several minke whales were recorded off Cape Starichkof in early 
summer 2013 during exploratory drilling (Owl Ridge 2014), suggesting 
this location may be used by minke whales year-round. During Apache's 
2014 survey, a total of two minke whale groups (totaling three 
individuals) were observed during this time period, one sighting to the 
southeast of Kalgin Island and another sighting near Homer (Lomac-
MacNair et al. 2014). SAExploration noted one minke whale near Tuxedni 
Bay in 2015 (Kendall et al. 2015). There were eight sightings of eight 
minke whales observed in the 2019 Hilcorp lower Cook Inlet seismic 
survey in the fall (Fairweather Science 2020). This higher number of 
minke whales suggests these offshore waters of lower Cook Inlet may be 
utilized by minke whales in greater numbers than previously estimated, 
particularly during the fall period. No minke whales were observed 
during the 2018 CIPL project (Sitkiewicz et al. 2018).

Fin Whale

    Fin whales are listed as endangered under the ESA in 1990 and 
depleted under the MMPA. For management purposes, three stocks of fin 
whales are currently recognized in United States (U.S.) Pacific waters: 
Alaska (Northeast Pacific), California/Washington/Oregon, and Hawaii. 
Recent analyses provide evidence that the population structure should 
be reviewed and possibly updated, however substantially new data on the 
stock structure is lacking (Muto et al. 2019).The Northeast Pacific 
stock is categorized as a strategic stock. No critical habitat has been 
designated or proposed for fin whales in the North Pacific.
    Fin whales are usually observed as individuals traveling alone, 
although they are sometimes observed in small groups. Rarely, large 
groups of 50 to 300 fin whales can travel together during migrations 
(NMFS 2010a). Fin whales in the Cook Inlet have only been observed as 
individuals or in small groups. Fin whales are vulnerable to natural 
and anthropogenic variables. Impacts on prey quality and distribution 
could affect distribution and energetics. The natural range of fin 
whales could be expanded due to sea ice melting and expanded available 
habitat. This could also result in increased exposure to shipping and 
other commercial activities. Toxicity and resulting deaths, as seen in 
recent years, from harmful algal blooms producing biotoxins could 
result from warming waters (Muto et al. 2021).
    In the U.S. Pacific waters, fin whales are found seasonally in the 
Gulf of Alaska, Bering Sea, and as far north as the northern Chukchi 
Sea (Muto et al. 2019). Surveys conducted in coastal waters of the 
Aleutians and the Alaska Peninsula found fin whales occurred primarily 
from the Kenai Peninsula to the Shumagin Islands and were abundant near 
the Semidi Islands and Kodiak Island (Zerbini et al. 2006). An 
opportunistic survey conducted on the shelf of the Gulf of Alaska found 
fin whales concentrated west of Kodiak Island in Shelikof Strait, and 
in the southern Cook Inlet region. In the northeastern Chukchi Sea, 
visual sightings and acoustic detections have been increasing, which 
suggests the stock may be re-occupying habitat used prior to large-
scale commercial whaling (Muto et al. 2019). Most of these areas are 
feeding habitat for fin whales. Watkins et al. (2000), and Stafford et 
al. (2007) documented high rates of calling along the Alaska coast 
beginning in August/September and lasting through February. Fin whales 
are regularly observed in the Gulf of Alaska during the summer months, 
even though calls are seldom detected during this period (Stafford et 
al. 2007). Instruments moored in the southeast Bering Sea detected 
calls over the course of a year and found peaks from September to 
November as well as in February and March (Stafford et al. 2010). 
Delarue et al. (2013) detected calls in the northeastern Chukchi Sea 
from instruments moored from July through October from 2007 through 
2010.
    Fin whales are rarely observed in Cook Inlet and most sightings 
occur near the entrance of the inlet. During the

[[Page 27606]]

NMFS aerial surveys in Cook Inlet from 2000 to 2018, 10 sightings of 26 
estimated individual fin whales in lower Cook Inlet were observed 
(Shelden et al. 2013, 2015, 2017; Shelden and Wade 2019). There were 
eight sightings of 23 fin whales observed in the 2019 Hilcorp lower 
Cook Inlet seismic survey in the fall (Fairweather Science 2020). This 
higher number of fin whale sightings suggests these offshore waters of 
lower Cook Inlet may be utilized by fin whales in greater numbers than 
previously estimated, particularly during the fall period.

Beluga Whale

    The Cook Inlet beluga whale stock is a small geographically 
isolated population that is separated from other beluga populations by 
the Alaska Peninsula. The population is genetically distinct from other 
Alaska populations suggesting the Peninsula is an effective barrier to 
genetic exchange (O'Corry-Crowe et al. 1997). The Cook Inlet beluga 
whale population is estimated to have declined from 1,300 animals in 
the 1970s (Calkins 1989) to about 340 animals in 2014 (Shelden et al. 
2015). The current population estimate is 279 animals (Shelden and Wade 
2019). In 1999, beluga hunters agreed to a moratorium on hunting to 
protect the species, from 2000 through 2005 one strike per year was 
allowed and taken in all but 2004, and since 2006 no Cook Inlet belugas 
have been harvested by subsistence users (Muto et al. 2021).
    NMFS designated the population as depleted under the MMPA in 2000 
and listed it as endangered under the ESA in 2008 when the population 
failed to recover following a moratorium on subsistence harvest (65 FR 
34590; May 31, 2000). In April 2011, NMFS designated critical habitat 
for the beluga under the ESA (76 FR 20180; April 11, 2011). NMFS 
finalized the Conservation Plan for the Cook Inlet beluga in 2008 (NMFS 
2008a) and the Recovery Plan for Cook Inlet beluga whales in 2016 (NMFS 
2016a). During the most recent 10-year time period (2008 to 2018), the 
population of Cook Inlet belugas experienced a decline of about 2.3 
percent per year (Wade et al. 2019). Threats that have the potential to 
impact this stock and its habitat include the following: Changes in 
prey availability due to natural environmental variability, ocean 
acidification, and commercial fisheries; climatic changes affecting 
habitat; predation by killer whales; contaminants; noise; ship strikes; 
waste management; urban runoff; construction projects; and physical 
habitat modifications that may occur as Cook Inlet becomes increasingly 
urbanized (Moore et al., 2000, Lowry et al., 2006, Hobbs et al., 2015, 
NMFS, 2106). Planned projects that may alter the physical habitat of 
Cook Inlet include highway improvements; mine construction and 
operation; oil and gas exploration and development; and expansion and 
improvements to ports.
    Generally, female beluga whales reach sexual maturity at 9 to 12 
years old, while males reach maturity later (O'Corry-Crowe 2009); 
however, this can vary between populations. For example, in Greenland, 
males in a population of beluga whales were found to reach sexual 
maturity at 6 to 7 years of age and females at 4 to 7 years. (Heide-
Joregensen and Teilmann 1994). Suydam (2009) estimated that 50 percent 
of females were sexually mature at age 8.25 and the average age at 
first birth was 8.27 years for belugas sampled near Point Lay. Mating 
behavior in beluga whales typically occurs between February and June, 
peaking in March (Burns and Seaman 1986; Suydam 2009). In the Chukchi 
Sea, the gestation period of beluga whales was determined to be 14.9 
months, with a calving interval of two to three years and a pregnancy 
rate of 0.41, declining after 25 years of age (Suydam 2009). Calves are 
born between mid-June and mid-July and typically remain with the mother 
for up to 2 years of age (Suydam 2009).
    Several studies (Johnson et al. 1989; Klishin et al. 2000; Finneran 
et al. 2002; Erbe 2008; white et al. 1978; Awbrey et al. 1988; Ridgway 
et al. 2001; Finneran et al. 2005; Castellote et al. 2019) describe 
beluga whale hearing capabilities. One study on beluga whales captured 
and released in Bristol Bay, Alaska measured hearing ranges at 4 to 150 
kHz with greatest variation between individuals at the high end of the 
auditory range in combination with frequencies near the maximum 
sensitivity (Castellote et al. 2014). All animals tested heard well up 
to 128 kHz, with two individuals hearing up to 150 kHz (Castellote et 
al. 2014). Beluga whales are included in the NMFS-identified mid-
frequency functional hearing group.
    The Cook Inlet beluga stock remains within Cook Inlet throughout 
the year (Goetz et al. 2012a). Two areas, consisting of 7,809 square 
kilometers (km\2\) of marine and estuarine environments considered 
essential for the species' survival and recovery, were designated 
critical habitat. However, in recent years the range of the beluga 
whale has contracted to the upper reaches of Cook Inlet (Rugh et al. 
2010). Area 1 of the Cook Inlet beluga whale critical habitat 
encompasses all marine waters of Cook Inlet north of a line connecting 
Point Possession (61.04[deg] N, 150.37[deg] W) and the mouth of 
Threemile Creek (61.08.55[deg] N, 151.04.40[deg] W), including waters 
of the Susitna, Little Susitna, and Chickaloon Rivers below the mean 
higher high water line (MHHW). This area provides important habitat 
during ice-free months and is used intensively by Cook Inlet beluga 
between April and November for feeding and other biological functions 
(NMFS 2016a).
    Since 1993, NMFS has conducted annual aerial surveys in June, July, 
or August to document the distribution and abundance of beluga whales 
in Cook Inlet. The collective survey results show that beluga whales 
have been consistently found near or in river mouths along the northern 
shores of middle and upper Cook Inlet. In particular, beluga whale 
groups are seen in the Susitna River Delta, Knik Arm, and along the 
shores of Chickaloon Bay. Small groups had also been recorded farther 
south in Kachemak Bay, Redoubt Bay (Big River), and Trading Bay 
(McArthur River) prior to 1996, but very rarely thereafter. Since the 
mid-1990s, most beluga whales have been concentrated in shallow areas 
near river mouths north and east of Beluga River and Point Possession 
(Hobbs et al. 2008). Based on these aerial surveys, there is a 
consistent pattern of beluga whale presence in the northernmost portion 
of Cook Inlet from June to October (Rugh et al. 2000, 2004a, 2004b, 
2005, 2006, 2007).
    Though Cook Inlet beluga whales can be found throughout the inlet 
at any time of year, generally they spend the ice-free months in the 
upper Cook Inlet, shifting into deeper waters in middle Cook Inlet in 
winter (Hobbs et al. 2008). In 1999, one beluga whale was tagged with a 
satellite transmitter, and its movements were recorded from June 
through September of that year. Since 1999, 18 beluga whales in upper 
Cook Inlet have been captured and fitted with satellite tags to provide 
information on their movements during late summer, fall, winter, and 
spring. Using location data from satellite-tagged Cook Inlet belugas, 
Ezer et al. (2013) found most tagged whales were in the lower to middle 
inlet during January through March, near the Susitna River Delta from 
April to July) and in the Knik and Turnagain Arms from August to 
December.
    During the spring and summer, beluga whales are generally 
concentrated near the warmer waters of river mouths where prey 
availability is high and predator occurrence is low (Moore et al. 
2000). Beluga whales in Cook Inlet are

[[Page 27607]]

believed to mostly calve between mid-May and mid-July, and concurrently 
breed between late spring and early summer (NMFS 2016a), primarily in 
upper Cook Inlet. Beluga movement was correlated with the peak 
discharge of seven major rivers emptying into Cook Inlet. Boat-based 
surveys from 2005 to the present (McGuire and Stephens 2017), and 
initial results from passive acoustic monitoring across the entire 
inlet (Castellote et al. 2016) also support seasonal patterns observed 
with other methods, and other surveys confirm Cook Inlet belugas near 
the Kenai River during summer months (McGuire and Stephens 2017).
    During the summer and fall, beluga whales are concentrated near the 
Susitna River mouth, Knik Arm, Turnagain Arm, and Chickaloon Bay 
(Nemeth et al. 2007) where they feed on migrating eulachon 
(Thaleichthys pacificus) and salmon (Onchorhyncus spp.) (Moore et al. 
2000). Data from tagged whales (14 tags between July and March 2000 
through 2003) show beluga whales use upper Cook Inlet intensively 
between summer and late autumn (Hobbs et al. 2005). Critical Habitat 
Area 1 encompasses this summer distribution.
    As late as October, beluga whales tagged with satellite 
transmitters continued to use Knik Arm and Turnagain Arm and Chickaloon 
Bay, but some ranged into lower Cook Inlet south to Chinitna Bay, 
Tuxedni Bay, and Trading Bay (McArthur River) in the fall (Hobbs et al. 
2005). Data from NMFS aerial surveys, opportunistic sighting reports, 
and satellite-tagged beluga whales confirm they are more widely 
dispersed throughout Cook Inlet during the winter months (November to 
April), with animals found between Kalgin Island and Point Possession. 
In November, beluga whales moved between Knik Arm, Turnagain Arm, and 
Chickaloon Bay, similar to patterns observed in September (Hobbs et al. 
2005). By December, beluga whales were distributed throughout the upper 
to middle Cook Inlet. From January into March, they moved as far south 
as Kalgin Island and slightly beyond in central offshore waters. Beluga 
whales also made occasional excursions into Knik Arm and Turnagain Arm 
in February and March despite ice cover greater than 90 percent (Hobbs 
et al. 2005). Critical Habitat Area 2 encompasses some of the fall and 
winter feeding grounds in middle Cook Inlet.
    Ferguson et al. (2015) delineated one `Small' and `Resident' BIA 
for Cook Inlet beluga whales. Small and Resident BIAs are defined as 
``areas and time within which small and resident populations occupy a 
limited geographic extent'' (Ferguson et al. 2015). The Cook Inlet 
beluga whale BIA was delineated using the habitat model results of 
Goetz et al. 2012 and the critical habitat boundaries and overlaps with 
both Critical Habitat Areas 1 and 2.
    During Apache's seismic test program in 2011 along the west coast 
of Redoubt Bay, lower Cook Inlet, a total of 33 beluga whales were 
sighted during the survey (Lomac-MacNair et al. 2013). During Apache's 
2012 seismic program in mid-inlet, a total of 151 sightings consisting 
of an estimated 1,463 beluga whales were observed (Lomac-MacNair et al. 
2014). During SAExploration's 2015 seismic program, a total of eight 
sightings of 33 estimated individual beluga whales were visually 
observed during this time period and there were two acoustic detections 
of beluga whales (Kendall et al. 2015). During Harvest Alaska's recent 
CIPL project on the west side of Cook Inlet in between Ladd Landing and 
Tyonek Platform, a total of 143 beluga whale sightings (814 
individuals) were observed almost daily from May 31 to July 11, even 
though observations spanned from May 9 through September 15 (Sitkiewicz 
et al. 2018). There were two beluga whale carcasses observed by the 
project vessels in the 2019 Hilcorp lower Cook Inlet seismic survey in 
the fall which were reported to the NMFS Marine Mammal Stranding 
Network (Fairweather Science 2020). Both carcasses were moderately 
decomposed when they were sighted by the PSOs. Daily aerial surveys 
specifically for beluga whales were flown over the lower Cook Inlet 
region, but no beluga whales were observed.

Killer Whale

    Based on data regarding association patterns, acoustics, movements, 
and genetic differences, eight killer whale stocks are now recognized 
within the Pacific U.S. Exclusive Economic Zone. Two different stocks 
of killer whales inhabit the Cook Inlet region of Alaska: The Alaska 
Resident Stock and the Gulf of Alaska, Aleutian Islands, Bering Sea 
Transient Stock (Muto et al. 2021). The Alaska Resident Stock and the 
Gulf of Alaska, Aleutian Islands, Bering Sea Transient Stock of killer 
whales are not designated as depleted under the MMPA or listed as 
threatened or endangered under the ESA. Reliable data on population 
trends for these killer whale stocks are unavailable (Muto et al. 
2021).
    Resident and transient killer whales from the Alaska Resident Stock 
and the Gulf of Alaska, Aleutian Islands, and Bering Sea Transient 
Stock occur in Cook Inlet (Allen and Angliss 2015), though rarely in 
middle and upper Cook Inlet. Transient killer whales feed on beluga 
whales and other marine mammals, and resident populations feed on 
anadromous fish (Shelden et al. 2003). The likelihood of killer whale 
occurrence depends on prey availability (NOAA 2019). Threats to and 
vulnerabilities of killer whales include natural causes, such as 
predation, and anthropogenic factors such as climate change, fishing 
operations and vessel strikes (Muto et al. 2016).
    Killer whales are occasionally observed in lower Cook Inlet, 
especially near Homer and Port Graham (Shelden et al. 2003; Rugh et al. 
2005). The few whales that have been photographically identified in 
lower Cook Inlet belong to resident groups more commonly found in 
nearby Kenai Fjords and Prince William Sound (Shelden et al. 2003). The 
availability of prey species largely determines the likeliest times for 
killer whales to be in the area. During aerial surveys conducted 
between 1993 and 2004, killer whales were observed on only three 
flights, all in the Kachemak and English Bay area (Rugh et al. 2005). 
However, anecdotal reports of killer whales feeding on belugas in 
middle and upper Cook Inlet began increasing in the 1990s, possibly in 
response to declines in sea lion and harbor seal prey elsewhere 
(Shelden et al. 2003).
    One killer whale group of two individuals was observed during the 
2015 SAExploration seismic program near the North Foreland (Kendall et 
al. 2015). During NMFS aerial surveys, killer whales were observed in 
1994 (Kamishak Bay), 1997 (Kachemak Bay), 2001 (Port Graham), 2005 
(Iniskin Bay), 2010 (Elizabeth and Augustine Islands), and 2012 
(Kachemak Bay; Shelden et al. 2013). Eleven killer whale strandings 
have been reported in Turnagain Arm, six in May 1991, and five in 
August 1993. There were six sightings of 21 killer whales observed in 
the 2019 Hilcorp lower Cook Inlet seismic survey in the fall 
(Fairweather Science 2020). This species is expected to be rarely seen 
in upper Cook Inlet but may be encountered in the middle and lower 
Inlet. However, no killer whales were observed during the 4-month CIPL 
project in middle Cook Inlet in 2018 (Sitkiewicz et al. 2018).

Harbor Porpoise

    In Alaskan waters, three stocks of harbor porpoises are currently 
recognized for management purposes: Southeast Alaska, Gulf of Alaska, 
and Bering Sea Stocks (Muto et al. 2019). Porpoises found in Cook Inlet 
belong to the Gulf of Alaska Stock which is distributed from Cape 
Suckling to

[[Page 27608]]

Unimak Pass and most recently was estimated to number 31,046 
individuals (Muto et al. 2019). Harbor porpoises are regularly seen 
throughout Cook Inlet (Nemeth et al. 2007), especially during spring 
eulachon and summer salmon runs. Harbor porpoises are not designated as 
depleted under the MMPA or listed as threatened or endangered under the 
ESA.
    Harbor porpoises primarily frequent the coastal waters of the Gulf 
of Alaska and Southeast Alaska (Dahlheim et al. 2000, 2008), typically 
occurring in waters less than 100 m deep (Hobbs and Waite 2010). The 
range of the Gulf of Alaska stock includes the entire Cook Inlet, 
Shelikof Strait, and the Gulf of Alaska. Harbor porpoises have been 
reported in lower Cook Inlet from Cape Douglas to the West Foreland, 
Kachemak Bay, and offshore (Rugh et al. 2005). Although they have been 
frequently observed during aerial surveys in Cook Inlet (Shelden et al. 
2014), most sightings are of single animals, and are concentrated at 
Chinitna and Tuxedni bays on the west side of lower Cook Inlet (Rugh et 
al. 2005) and in the upper inlet. The occurrence of larger numbers of 
porpoise in the lower Cook Inlet may be driven by greater availability 
of preferred prey and possibly less competition with beluga whales, as 
belugas move into upper inlet waters to forage on Pacific salmon 
(Oncorhynchus spp.) during the summer months (Shelden et al. 2014). 
Recent passive acoustic research in Cook Inlet by Alaska Department of 
Fish and Game (ADF&G) and MML have indicated that harbor porpoises 
occur more frequently than expected, particularly in the West Foreland 
area in the spring (Castellote et al. 2016).
    The harbor porpoise frequently has been observed during summer 
aerial surveys of Cook Inlet, with most sightings of individuals 
concentrated at Chinitna and Tuxedni Bays on the west side of lower 
Cook Inlet (Rugh et al. 2005). Mating likely occurs from June or July 
to October, with peak calving in May and June (Consiglieri et al. 
1982). Small numbers of harbor porpoises have been consistently 
reported in the upper Cook Inlet between April and October, except for 
a recent survey that recorded higher numbers than typical. NMFS aerial 
surveys have routinely identified many harbor porpoise sightings 
throughout Cook Inle. During Apache's 2012 seismic program, 137 
sightings (190 individuals) were observed between May and August 
(Lomac-MacNair et al. 2013). Lomac-MacNair et al. 2014 identified 77 
groups of harbor porpoise totaling 13 individuals during Apache's 2014 
seismic survey, both from vessels and aircraft, during the month of 
May. During SAExploration's 2015 seismic survey, 52 sightings (65 
individuals) were observed north of the Forelands (Kendall et al. 
2015). There were 2 sightings of 3 harbor porpoises observed during the 
2019 Hilcorp lower Cook Inlet seismic survey in the fall (Fairweather 
Science 2020). A total of 29 sightings (44 individuals) were observed 
north of the Forelands from May to September during the Harvest Alaska 
CIPL project (Sitkiewicz et al. 2018). During jack-up rig moves in 
2021, a Protected Species Observer (PSO) observed two individual harbor 
porpoises in middle Cook Inlet, one in July and one in October.

Dall's Porpoise

    Dall's porpoises are widely distributed across the North Pacific, 
but they are infrequently sighted in upper Cook Inlet (Muto et al. 
2020). Dall's porpoises have been observed in lower Cook Inlet, around 
Kachemak Bay, and rarely near Anchor Point (BOEM 2015). Dall's 
porpoises are not designated as depleted under the MMPA or listed as 
threatened or endangered under the ESA (Muto et al. 2019). Threats to 
and vulnerabilities of Dall's porpoises include natural and 
anthropogenic factors such as habitat modifications and climate change. 
The nearshore areas, bays, channels, and inlets where Dall's porpoises 
frequent are of particular concern. These areas are subject to 
substantial changes with urbanization and industrialization, including 
waste management and nonpoint source runoff (Linnenschmidt et al. 
2013).
    Throughout most of the eastern North Pacific they are present 
during all months of the year, although there may be seasonal onshore-
offshore movements along the west coast of the continental U.S. and 
winter movements of populations out of areas with ice such as Prince 
William Sound (Muto et al. 2019). No Dall's porpoises were observed 
during the CIPL project monitoring program in middle Cook Inlet in 2018 
(Sitkiewicz et al. 2018). Dall's porpoises were observed (two groups of 
three individuals) during Apache's 2014 seismic survey which occurred 
in the summer months (Lomac-MacNair et al. 2014). Dall's porpoises were 
observed during the month of June in 1997 (Iniskin Bay), 199 (Barren 
Island), and 2000 (Elizabeth Island, Kamishak Bay and Barren Island) 
(Shelden et al. 2013). Dall's porpoises have been observed in lower 
Cook Inlet, including Kachemak Bay and near Anchor Point (Owl Ridge 
2014). One Dall's porpoise was observed in August north of Nikiski in 
the middle of the Inlet during SAExploration's 2015 seismic program 
(Kendall et al. 2015). There were 10 sightings of 30 Dall's porpoises 
observed during the 2019 Hilcorp lower Cook Inlet seismic survey in the 
fall (Fairweather Science 2020).

Steller Sea Lion

    The Western DPS of Steller sea lions is currently listed as 
endangered under the ESA (55 FR 49204; November 26, 1990) and 
designated as depleted under the MMPA. Critical habitat was designated 
on August 27, 1993 (58 FR 45269; August 27, 1993) south of the proposed 
action area in the Cook Inlet region. The critical habitat designation 
for the Western DPS of Steller sea lions includes a 37 km buffer around 
all major haul outs and rookeries, and associated terrestrial, 
atmospheric, and aquatic zones, plus three large offshore foraging 
areas, as well as designated no entry zones around rookeries (50 CFR 
223.202). Designated critical habitat is located outside Cook Inlet at 
Gore Point, Elizabeth Island, Perl Island, and Chugach Island (NMFS 
2008b). The Western DPS of the Steller sea lion is defined as all 
populations west of longitude 144[deg] W to the western end of the 
Aleutian Islands.
    Steller sea lions are not migratory animals but exhibit wide 
dispersion in the non-breeding season (Loughlin 1997). They are 
polygynous in nature, with one male typically breeding with large 
numbers of females. Steller sea lions tend to haul out in large groups.
    Underwater vocalizations of Steller sea lions have been noted to 
include belches, barks, and clicks (Kastelein et al. 2005). Audiograms 
have revealed a maximum underwater hearing sensitivity at 77 dB RL at 
1kHz for a male Steller sea lion, with a range of best hearing at 10 dB 
from the maximum sensitivity, of between 1 and 16 kHz. His average pre-
stimulus responses occurred at low frequency signals. Similar 
audiograms of a female Steller sea lion revealed a maximum hearing 
sensitivity of 73 dB received level, occurring at 25 kHz, indicating 
that low frequency sounds are audible to Steller sea lions (Kastelein 
et al. 2005).
    Steller sea lions feed largely on walleye pollock (Theragra 
chalcogramma), salmon (Onchorhyncus spp.), and arrowtooth flounder 
(Atheresthes stomias) during the summer, and walleye pollock and 
Pacific cod (Gadus macrocephalus) during the winter (Sinclair and 
Zeppelin 2002). Except for salmon, these species are not found in

[[Page 27609]]

abundance in upper Cook Inlet (Nemeth et al. 2007). Threats to and 
vulnerabilities of Steller sea lions include natural and anthropogenic 
factors, including depletion of prey availability from fishing 
activities, climate change, disease, contaminants, predation by killer 
whales, incidental take, and illegal and legal shooting (Atkinson et 
al. 2008, NMFS 2008), harmful algal blooms (Lefebvre et al. 2016), 
disease proliferation from warming waters (VanWormer et al. 2019), and 
potentially metal and contaminant exposure (Rea et al. 2013; Beckmen et 
al. 2016, Keogh et al. 2020).
    Steller sea lions inhabit lower Cook Inlet, especially near Shaw 
Island and Elizabeth Island (Nagahut Rocks) haul out sites (Rugh et al. 
2005) but are rarely seen in upper Cook Inlet (Nemeth et al. 2007). 
Steller sea lions occur in Cook Inlet but south of Anchor Point around 
the offshore islands and along the west coast of the upper inlet in the 
bays (Chinitna Bay, Iniskin Bay, etc.) (Rugh et al. 2005). Portions of 
the southern reaches of the lower inlet are designated as critical 
habitat, including a 37 km (20 nautical mile) buffer around all major 
haul out sites and rookeries. Rookeries and haul out sites in lower 
Cook Inlet include those near the mouth of the inlet, which are far 
south of the Action Area.
    Steller sea lions have been observed during marine mammal surveys 
conducted in Cook Inlet. In 2012, during Apache's 3D Seismic surveys, 
there were three sightings of approximately four individuals in upper 
Cook Inlet (Lomac-MacNair et al. 2013). Marine mammal observers 
associated with Buccaneer's drilling project off Cape Starichkof 
observed seven Steller sea lions during the summer of 2013 (Owl Ridge 
2014). During SAExploration's 3D Seismic Program in 2015, four Steller 
sea lions were observed in Cook Inlet. One sighting occurred between 
the West and East Forelands, one near Nikiski and one northeast of the 
North Foreland in the center of Cook Inlet (Kendall et al. 2015). There 
were five sightings of five Steller sea lions observed during the 2019 
Hilcorp lower Cook Inlet seismic survey in the fall (Fairweather 
Science 2020). One sighting of two individuals occurred during the CIPL 
project in 2018 in middle Cook Inlet (Sitkiewicz et al. 2018). During 
NMFS Cook Inlet beluga whale aerial surveys from 2000 to 2016, there 
were 39 sightings of 769 estimated individual Steller sea lions in 
lower Cook Inlet (Shelden et al. 2017). Sightings of large 
congregations of Steller sea lions during NMFS aerial surveys occurred 
outside the Action Area, on land in the mouth of Cook Inlet (e.g., 
Elizabeth and Shaw Islands).

California Sea Lion

    California sea lions in the U.S. are not listed as endangered or 
threatened under the ESA or as depleted or strategic under the MMPA. 
The growth rate of the species is approximately seven percent annually 
(Carretta et al. 2020). There is limited information on the presence of 
California sea lions in Alaska. California sea lion presence in Alaska 
was correlated with increasing population numbers within their southern 
breeding range (Maniscalco et al. 2004). California sea lions are not 
commonly observed in Alaska. When they are observed, they are often 
alone or, less commonly, in groups of two or more. They are most often 
associated with Steller sea lions at their haulouts and rookeries 
(Maniscalco et al. 2004). Threats to and vulnerabilities of California 
sea lions include natural and anthropogenic factors including climate 
change, exposure to harmful algal neurotoxins (Scholin et al. 2000, 
Brodie et al. 2006, Ramsdell and Zabka 2008), shootings, entrainment in 
industrial facilities, fishing gear interactions, vessel strikes, and 
human disturbance (Muto et al. 2019).
    California sea lions are not typically observed farther north than 
southeast Alaska, and sightings are very rare in Cook Inlet. California 
sea lions have not been observed during the annual NMFS aerial surveys 
in Cook Inlet. However, a sighting of two California sea lions was 
documented during the Apache 2012 seismic survey (Lomac-MacNair et al. 
2013). Additionally, NMFS' anecdotal sighting database has four 
sightings in Seward and Kachemak Bay. There were no California sea 
lions observed during the 2019 Hilcorp lower Cook Inlet seismic survey 
(Fairweather Science 2020) or the CIPL project in 2018 (Sitkiewicz et 
al. 2018).

Harbor Seal

    In 2010, NMFS and their co-management partners, the Alaska Native 
Harbor Seal Commission, defined 12 separate stocks of harbor seals 
based largely on genetics. The harbor seal stocks present in the action 
area are from the Cook Inlet/Shelikof stock. No harbor seal stocks in 
Alaska are designated as depleted under the MMPA or listed as 
threatened or endangered under the ESA (Muto et al. 2019).
    In Cook Inlet, large harbor seal haulout areas are located in lower 
Cook Inlet, with occurrence in upper inlet coinciding with prey 
availability. Harbor seals frequent the Susitna River and other rivers 
feeding into upper Cook Inlet when eulachon and salmon are migrating in 
those areas (NMFS, 2003). Harbor seals haul out on rocks, reefs, 
beaches, and drifting glacial ice. Prey species include capelin, 
eulachon, cod, pollock, flatfish, shrimp, octopus, and squid. Threats 
to and vulnerabilities of harbor seals include natural and 
anthropogenic factors including climate change, shipping, and tour 
vessel traffic (Muto et al. 2021).
    The major haul out sites for harbor seals are located in lower Cook 
Inlet and their presence in middle and upper Cook Inlet is seasonal. In 
Cook Inlet, seal use of western habitats is greater than use of the 
eastern coastline (Boveng et al. 2012). NMFS has documented a strong 
seasonal pattern of more coastal and restricted spatial use during the 
spring and summer for breeding, pupping, and molting, and more wide-
ranging seal movements within and outside of Cook Inlet during the 
winter months (Boveng et al. 2012). Large-scale movement patterns 
indicate a portion of harbor seals captured in Cook Inlet move out of 
the area in the fall, and into habitats within Shelikof Strait, 
Northern Kodiak Island, and coastal habitats of the Alaska Peninsula, 
and are most concentrated in Kachemak Bay, across Cook Inlet toward 
Iniskin and Iliamna Bays, and south through the Kamishak Bay, Cape 
Douglas, and Shelikof Strait regions (Boveng et al. 2012).
    The Cook Inlet/Shelikof Stock is distributed from Anchorage into 
lower Cook Inlet during summer and from lower Cook Inlet through 
Shelikof Strait to Unimak Pass during winter (Boveng et al. 2012). 
Large numbers concentrate at the river mouths and embayments of lower 
Cook Inlet, including the Fox River mouth in Kachemak Bay, and several 
haul outs have been identified on the southern end of Kalgin Island in 
lower Cook Inlet (Rugh et al. 2005; Boveng et al. 2012). Montgomery et 
al. (2007) recorded over 200 haul-out sites in lower Cook Inlet alone.
    NMFS aerial surveys have routinely identified many harbor seal 
sightings throughout Cook Inlet over the past 20 years of survey 
effort. During Apache's 2012 seismic program, harbor seals were 
observed in the project area from early May until the end of the 
seismic operations in late September (Lomac-MacNair et al. 2013). Up to 
100 harbor seals were observed hauled out at the mouths of the Theodore 
and Lewis rivers during monitoring activity. During Apache's 2014 
seismic program, 492 groups of harbor seals (613 individuals) were 
observed; this highest sighting rate of any marine mammal

[[Page 27610]]

observed during the summer of 2014 (Lomac-MacNair et al. 2014). During 
SAExploration's 2015 seismic survey, 823 sightings (1,680 individuals) 
were observed north and between the Forelands (Kendall et al. 2015). 
Recently, a total of 313 sightings (316 individuals) were observed near 
Ladd Landing for the Harvest Alaska CIPL project during the summer 
(Sitkiewicz et al. 2018). There were 10 sightings of 10 harbor seals 
observed during the 2019 Hilcorp lower Cook Inlet seismic survey in the 
fall (Fairweather Science 2020). During a Hilcorp jack-up rig move in 
2021, one pinniped of an unidentified species was observed in July in 
middle Cook Inlet.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 5.

                  Table 5--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

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

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species or 
stocks.
    The proposed project includes the use of three tugs towing a jack-
up rig, which would emit consistent, low levels of noise into a small 
portion of Cook Inlet for an extended period of time. Hilcorp's tugging 
and positioning activities would occur for approximately 16 days in 
Year 1 and 16 days in Year 2 to support overall production and well 
plug and abandonment operations that would occur across 210 days in 
Year 1 and 180 days in Year 2. Unlike projects that involve discrete 
noise sources with known potential to harass marine mammals (e.g., pile 
driving, seismic surveys), both the noise sources and impacts from the 
tugs towing the jack-up rig are less well documented. In light of the 
aforementioned court decision we have re-examined the available 
information. The various scenarios that may occur during this project 
extend from tugs in a stationary mode, positioning the drill rig to 
pulling the jack-up rig at nearly full power against strong tides. Our 
assessments of the potential for harassment of marine mammals 
incidental to Hilcorp's tug activities specified here are conservative 
in light of the general Level B harassment exposure thresholds, the 
fact that NMFS is still in the process of developing analyses of the 
impact that non-quantitative contextual factors have on the likelihood 
of Level B harassment occurring, and the nature and duration of the 
particular tug activities analyzed here.
    The proposed project has the potential to harass marine mammals 
from exposure to noise and the physical presence of working vessels 
(e.g., three tug configuration) as well as associated noise with the 
positioning of the jack-up rig. In this case, NMFS considers potential 
for harassment from the collective use of these technologies working in 
a concentrated area (relative to the entire Cook Inlet) for an extended 
period of time (when making multiple positioning attempts) and noise 
created when moving the jack-up rig using three tugs. Essentially, the 
project area will become a concentrated work area in an otherwise non-
industrial setting for a period of several days. Accordingly the 
Estimated Take section proposes to authorize take, by Level B 
harassment,

[[Page 27611]]

from tug towing activities over the course of 16 days of activity each 
year.

Auditory Effects

    NMFS defines a noise-induced threshold shift (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 
threshold shift is customarily expressed in dB (ANSI 1995, Yost 2007). 
A TS can be permanent (PTS) or temporary (TTS). As described in NMFS 
(2016), 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; e.g., 
Kastelein et al., 2014), and the overlap between the animal and the 
source (e.g., spatial, temporal, and spectral). When analyzing the 
auditory effects of noise exposure, it is often helpful to broadly 
categorize sound as either impulsive--noise with high peak sound 
pressure, short duration, fast rise-time, and broad frequency content--
or non-impulsive. For example, when considering auditory effects, 
vibratory pile driving is considered a non-impulsive source while 
impact pile driving is treated as an impulsive source. The sounds 
produced by tugs towing and positioning the jack-up rig are 
characterized as non-impulsive sounds.
    Permanent Threshold Shift--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 threshold 
shift approximates PTS onset (see NMFS 2018 for review).
    Temporary Threshold Shift--NMFS defines TTS as 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 Finneran 2015 for a review), a TTS of 6 
dB is considered the minimum threshold shift clearly larger than any 
day-to-day or session-to-session variation in a subject's normal 
hearing ability (Schlundt et al., 2000; Finneran et al., 2002; 
Finneran, 2015).
    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 auditory 
masking, below). 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 times when hearing 
is critical, such as 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.

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 
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 animal detection and/or interpretation of acoustic 
signals such as communication calls, echolocation sounds, and 
environmental sounds important to marine mammals. 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.
    Masking occurs in the frequency band that the animals utilize. 
Since noises generated from tugs towing and positioning are mostly 
concentrated at low frequency ranges, with a small concentration in 
high frequencies as well, these activities likely have less effect on 
mid-frequency echolocation sounds by odontocetes (toothed whales) such 
as Cook Inlet beluga whales. However, lower frequency noises are more 
likely to affect detection of communication calls and other potentially 
important natural sounds such as surf and prey noise. Low-frequency 
noise may also affect communication signals when they occur near the 
noise band and thus reduce the communication space of animals (e.g., 
Clark et al., 2009) and cause increased stress levels (e.g., Holt et 
al., 2009). Unlike TS, masking, which can occur over large temporal and 
spatial scales, can potentially affect the species at population, 
community, or even ecosystem levels, in addition to individual levels. 
Masking affects both senders and receivers of the signals and at higher 
levels for longer durations could have long-term chronic effects on 
marine mammal species and populations. However, the noise generated by 
the tugs will not be concentrated in one location or for more than five 
hours per day and in the same geographic location for only two days per 
well site.

Behavioral Disturbance

    Finally, exposure of marine mammals to certain sounds could result 
in behavioral disturbance (Richardson et al., 1995), not all of which 
constitutes harassment under the MMPA. The onset of behavioral 
disturbance from anthropogenic noise depends on both external factors 
(e.g., characteristics of noise sources and their paths) and the 
receiving animals (e.g., hearing, behavioral state, experience, 
demography) and is difficult to predict (Southall et al., 2007, 2021). 
Currently NMFS uses a received level of 160 dB re 1 micro Pascal 
([mu]Pa) root mean square (rms) to predict the onset of behavioral 
harassment from impulse noises (such as impact pile driving), and 120 
dB re 1 [mu]Pa (rms) for continuous noises (such as operating dynamic 
positioning (DP) thrusters), although in certain circumstances there 
may be contextual factors that alter our assessment of the onset of 
behavioral harassment. No impulsive noise within the hearing range of 
marine mammals is expected from Hilcorp's proposed activities. For the 
tug towing and positioning activities, only the 120 dB re 1 [mu]Pa 
(rms) threshold is considered because only continuous noise sources 
would be generated.
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, moving

[[Page 27612]]

direction and/or speed, reduced/increased vocal activities; changing/
cessation of certain behavioral activities (such as socializing or 
feeding), visible startle response or aggressive behavior (such as 
tail/fluke slapping or jaw clapping), avoidance of areas where sound 
sources are located, and/or flight responses. Pinnipeds may increase 
their haul-out time, possibly to avoid in-water disturbance (Thorson 
and Reyff 2006). These potential behavioral responses to sound are 
highly variable and context-specific and reactions, if any, depend on 
species, state of maturity, experience, current activity, reproductive 
state, auditory sensitivity, time of day, and many other factors 
regarding the source eliciting the response (Richardson et al., 1995; 
Wartzok et al., 2004; Southall et al., 2007). For example, animals that 
are resting may show greater behavioral change in response to 
disturbing sound levels than animals that are highly motivated to 
remain in an area for feeding (Richardson et al., 1995; NRC 2003; 
Wartzok et al., 2004). The biological significance of many of these 
behavioral disturbances is difficult to predict, especially if the 
detected disturbances appear minor. However, the consequences of 
behavioral modification could be biologically significant if the change 
affects growth, survival, and/or reproduction, which depends on the 
severity, duration, and context of the effects.
    In consideration of the range of potential effects (PTS to 
behavioral disturbance), we consider the potential exposure scenarios 
and context in which species would be exposed to tug-related activity. 
Cook Inlet beluga whales may be present in low numbers during the work; 
therefore, some individuals may be reasonably expected to be exposed to 
elevated sound levels, including briefly those that exceed the Level B 
harassment threshold for continuous noise. However, beluga whales are 
expected to be transiting through the area, given this work is proposed 
primarily in middle Cook Inlet (as described in the Description of 
Marine Mammals in the Area of Specified Activities section), thereby 
limiting exposure duration, as belugas in the area are expected to be 
headed to or from the concentrated foraging areas farther north near 
the Beluga River, Susitna Delta, and Knik and Turnigan Arms. Similarly, 
humpback whales, fin whales, minke whales, killer whales, California 
sea lion, and Steller sea lions are not expected to remain in the area 
of the tugs. Dall's porpoise, harbor porpoise, and harbor seal have 
been sighted with more regularity than many other species during oil 
and gas activities in Cook Inlet but due to the transitory nature of 
porpoises, they are unlikely to remain at any particular well site for 
the full duration of the noise-producing activity. Because of this and 
the relatively low-level sources, the likelihood of PTS and TTS over 
the course of the tug activities is discountable. Harbor seals may 
linger or haul-out in the area but they are not known to do so in any 
large number or for extended periods of time (there are no known major 
haul-outs or rookeries coinciding with the well sites). Here we find 
there is small potential for TTS over the course of tug activities but 
again, PTS is not likely due to the types of sources involved in the 
project.
    Given most marine mammals are likely transiting through the area, 
exposure is expected to be brief but, in combination with the actual 
presence of the tug and jack-up rig configuration, may result in 
animals shifting pathways around the work site (e.g., avoidance), 
increasing speed or dive times, or cessation of vocalizations. The 
likelihood of no more than a short-term, localized disturbance response 
is supported by data indicating belugas regularly pass by 
industrialized areas such as the Port of Anchorage; therefore, we do 
not expect abandonment of their transiting route or other disruptions 
of their behavioral patterns. We also anticipate some animals may 
respond with such mild reactions to the project that the response would 
not be detectable. For example, during low levels of power output 
(e.g., while tugs may be operating at low power because of favorable 
conditions), the animals may be able to hear the work but any resulting 
reactions, if any, are not expected to rise to the level of take.
    While in some cases marine mammals have exhibited little to no 
obviously detectable response to certain common or routine 
industrialized activity (Cornick et al, 2011), it is possible some 
animals may at times be exposed to received levels of sound above the 
Level B harassment threshold. This potential exposure in combination 
with the nature of the tug and jack-up rig configuration (e.g. 
difficult to maneuver, potential need to operate at night) means it is 
possible that take could occur over the total estimated period of tug 
activities; therefore, NMFS in response to Hilcorp's IHA application 
proposes to authorize take by Level B harassment from Hilcorp's use of 
tugs towing a jack-up rig for both positioning and straight-line tug 
activities.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determinations.
    Harassment is the only type of take reasonably expected to result 
from these activities. Except with respect to certain activities not 
pertinent here, section 3(18) of the MMPA defines ``harassment'' as any 
act of pursuit, torment, or annoyance, which (i) has the potential to 
injure a marine mammal or marine mammal stock in the wild (Level A 
harassment); or (ii) has the potential to disturb a marine mammal or 
marine mammal stock in the wild by causing disruption of behavioral 
patterns, including, but not limited to, migration, breathing, nursing, 
breeding, feeding, or sheltering (Level B harassment).
    Authorized takes would be by Level B harassment only, in the form 
of disruption of behavioral patterns for individual marine mammals 
resulting from exposure to the tugs towing and positioning the jack-up 
rig. Based on the nature of the activity, Level A harassment is neither 
anticipated nor proposed to be authorized.
    As described previously, no serious injury or mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) Acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent hearing impairment; (2) the 
area or volume of water that will be ensonified above these levels in a 
day; (3) the density or occurrence of marine mammals within these 
ensonified areas; and, (4) the number of days of activities. We note 
that while these factors can contribute to a basic calculation to 
provide an initial prediction of potential takes, additional 
information that can qualitatively inform take estimates is also 
sometimes available (e.g., previous monitoring results or average group 
size). 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

[[Page 27613]]

B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance or harassment from anthropogenic 
noise exposure is also informed to varying degrees by other factors 
related to the source or exposure context (e.g., frequency, 
predictability, duty cycle, duration of the exposure, signal-to-noise 
ratio, distance to the source), the environment (e.g., bathymetry, 
other noises in the area, predators in the area), and the receiving 
animals (hearing, motivation, experience, demography, life stage, 
depth) and can be difficult to predict (e.g., Southall et al., 2007, 
2021, Ellison et al., 2012). Accordingly, 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 reasonably estimate the onset of behavioral harassment. NMFS 
generally predicts that marine mammals are likely to be behaviorally 
harassed in a manner considered to be Level B harassment when exposed 
to underwater anthropogenic noise above root-mean-squared pressure 
received levels (RMS SPL) of 120 dB (referenced to 1 micropascal (re 1 
[mu]Pa)) for continuous (e.g., vibratory pile-driving, drilling) and 
above RMS SPL, 160 dB re 1 [mu]Pa (rms) for non-explosive impulsive 
(e.g., seismic airguns) or intermittent (e.g., scientific sonar) 
sources.
    Hilcorp's activity includes the use of continuous (tug towing and 
positioning the rig) sources, and therefore the RMS SPL 120 dB re 1 
[mu]Pa is applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (Technical Guidance, 2018) identifies dual 
criteria to assess auditory injury (Level A harassment) to five 
different marine mammal groups (based on hearing sensitivity) as a 
result of exposure to noise from two different types of sources 
(impulsive or non-impulsive). Hilcorp's proposed activity includes the 
use of non-impulsive (tugs towing rig) sources.
    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 [micro]Pa, and cumulative sound exposure level (LE)
  has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
  National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
  incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
  ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
  generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
  the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
  be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
  it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
    As described above in the Detailed Description of the Specific 
Activity, based on in situ measurements of Hilcorp's tug and a review 
of the available literature of tugs under load, a source level of 185 
dB re 1 [micro]Pa was used for Hilcorp's three tug configuration for 
towing the jack-up-rig. Hilcorp contracted SLR Consulting to model the 
extent of the Level B harassment isopleth as well as the extent of the 
PTS isopleth for their proposed activity.
    Rather than applying practical spreading loss, SLR created a more 
detailed propagation loss model in an effort to improve the accuracy of 
the results by considering the influence of environmental variables 
(e.g. bathymetry) at the specific well sites, as Hilcorp's operational 
locations are known in advance. Modeling was conducted using dBSea 
software. The fluid parabolic equation modeling algorithm was used with 
5 Pad[eacute] terms (see pg. 57 in Hilcorp's application for more 
detail) to calculate the transmission loss between the source and the 
receiver at low frequencies (1/3-octave bands, 31.5 Hz up to 1 kHz). 
For higher frequencies (1 kHz up to 8 kHz) the ray tracing model was 
used with 1,000 reflections for each ray. Sound sources were assumed to 
be omnidirectional and modeled as points. The received sound levels for 
the project were calculated as follows: (1) One-third octave source 
spectral levels were obtained via reference spectral curves with 
subsequent corrections based on their corresponding overall source 
levels; (2) Transmission loss was modeled at one-third octave band 
central frequencies along 100 radial paths at regular increments around 
each source location, out to the maximum range of the bathymetry data 
set or until constrained by land; (3) The bathymetry variation of the 
vertical plane along each modeling path was obtained via interpolation 
of the bathymetry dataset which has 83 m grid resolution; (4) The one-
third octave source levels and transmission loss were combined to 
obtain the received levels as a function of range, depth, and 
frequency; and (5) The overall received levels were calculated at a 1-m 
depth resolution along each propagation path by

[[Page 27614]]

summing all frequency band spectral levels.
    Model Inputs--Bathymetry data used in the model was collected from 
the NOAA National Centers for Environmental Information (AFSC 2019). 
Using NOAA's temperature and salinity data, sound speed profiles were 
computed for depths from 0 to 100 meters for May, July, and October to 
capture the range of possible sound speed depending on the time of year 
Hilcorp's work could be conducted. These sound speed profiles were 
compiled using the Mackenzie Equation (1981) and are presented in Table 
8 of Hilcorp's application. Geoacoustic parameters were also 
incorporated into the model. The parameters were based on substrate 
type and their relation to depth. These parameters are presented in 
Table 9 of Hilcorp's application.
    Detailed broadband sound transmission loss modeling in dBSea used 
the source level of 185 dB re 1 [mu]Pa at 1 m calculated in one-third 
octave band levels (31.5 Hz to 64,000 Hz) for frequency dependent 
solutions. The frequencies associated with tug sound sources occur 
within the hearing range of marine mammals in Cook Inlet. Received 
levels for each hearing marine mammal group based on one-third octave 
auditory weighting functions were also calculated and integrated into 
the modeling scenarios of dBSea. For modeling the distances to relevant 
PTS thresholds, a weighting factor adjustment was not used; instead, 
the data on the spectrum associated with their source was used and 
incorporated the full auditory weighting function for each marine 
mammal hearing group.
    Because Hilcorp plans to use the tugs towing the jack-up-rig for 
essentially two functions (positioning and towing), the activity was 
divided into two parts (stationary and mobile) and two approaches were 
taken for modeling the relevant isopleths.
    Stationary--For stationary activity, two locations representative 
of where tugs will be stationary positioning the jack-up rig were 
selected for the model. These locations are in middle Cook Inlet near 
the Tyonek platform, and in lower Trading Bay where the production 
platforms are located, with water depths of 40 m and 20 m respectively. 
The modeling at these locations assumed a stationary five-hour exposure 
to a broadband spectrum of 185 dB as described above. A five-hour 
exposure duration was chosen to account for the up to five-hour 
positioning attempts on individual days as well as events where the 
tugs need to hold the jack-up rig while waiting for a following tide. 
Stationary model results are presented in Table 7.
    Mobile--For the mobile portion of the activity, a representative 
route was used from the Rig Tender's dock in Nikiski to the Tyonek 
platform, the northernmost platform in Cook Inlet (representing Middle 
Cook Inlet), as well as from the Tyonek Platform to the Dolly Varden 
platform in lower Trading Bay and then from the Dolly Varden platform 
back to the Rig Tender's Dock in Nikiski. This route is representative 
of a typical route the tugs may take; the specific route is not yet 
known because the order in which platforms will be drilled with the 
jack-up rig is not yet known. The lowest threshold for the onset of PTS 
is for high frequency cetaceans at 173 dB. Based on a source level of 
185 dB, and assuming practical spreading, the high frequency cetacean 
PTS threshold of 173 dB would be reached at 6.3 meters away from the 
source. The mobile source modeling assumed a transit speed of 2.06 m/s 
for the tug configuration. With an assumed vessel speed of 2.06 m/s, it 
would take the vessel 6.11 seconds to traverse a distance of two times 
the radius, with two times the radius used because the source is 
omnidirectional and the ship is moving in a straight line. Although a 
source level of 185 dB incorporates the use of three tugs 
simultaneously, because the three tugs will likely not be perfectly 
aligned in space (e.g. one could lag slightly behind the forward two), 
three separate six second exposures were summed (one for each tug 
passing in space) to arrive at a total duration of exposure of 18 
seconds. While it is possible the duration of exposure could be as 
short as six seconds if all tugs were perfectly aligned, separate 
exposures for each tug were considered as the exact formation of the 
tugging vessels at any given time is unknown. Mobile source model 
results are presented in Table 8.
    Because there is no temporal component associated with NMFS' 
current Level B threshold, making it a potentially conservative 
assumption given the transitory nature of the rig towing activity, the 
results of the modeled distance to the 120 dB threshold for both 
stationary and mobile tug use are presented in Table 9 below. The 
average of these distances was used for calculation of estimated 
exposure to Level B harassment (3,850 m).
    The locations used in the stationary and mobile source models are 
depicted in Figure 2 below.

[[Page 27615]]

[GRAPHIC] [TIFF OMITTED] TN09MY22.031

    The outputs of the mobile and stationary models as distances to the 
relevant threshold (in meters) are presented below in Tables 7-9.

[[Page 27616]]



                                          Table 7--Average Distances to PTS Thresholds for Stationary Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Average distances (m) to PTS threshold by functional hearing group
                 Location                              Season            -------------------------------------------------------------------------------
                                                                                LF              MF              HF              PW              OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Trading Bay...............................  May.........................             100              72             716              59  ..............
Trading Bay...............................  July........................             122              73             697              63  ..............
Trading Bay...............................  October.....................              98              72             694              59  ..............
Middle Cook Inlet.........................  May.........................              83              83             643              77  ..............
Middle Cook Inlet.........................  July........................              89              85             664              78  ..............
Middle Cook Inlet.........................  October.....................              80              84             661              78  ..............
                                                                         -------------------------------------------------------------------------------
    Average...............................  ............................              95              78             679              69               0
--------------------------------------------------------------------------------------------------------------------------------------------------------


                                            Table 8--Average Distances to PTS Thresholds for Mobile Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Average distances (m) to PTS threshold by functional hearing group
                 Location                              Season            -------------------------------------------------------------------------------
                                                                                LF              MF              HF              PW              OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
M2........................................  May.........................  ..............  ..............              10  ..............  ..............
M2........................................  July........................  ..............  ..............               5  ..............  ..............
M2........................................  October.....................  ..............  ..............              10  ..............  ..............
M11.......................................  May.........................  ..............  ..............              10  ..............  ..............
M11.......................................  July........................  ..............  ..............               5  ..............  ..............
M11.......................................  October.....................  ..............  ..............              10  ..............  ..............
M22.......................................  May.........................  ..............  ..............              10  ..............  ..............
M22.......................................  July........................  ..............  ..............               5  ..............  ..............
M22.......................................  October.....................  ..............  ..............              10  ..............  ..............
                                                                         -------------------------------------------------------------------------------
    Average...............................  ............................               0               0               8               0               0
--------------------------------------------------------------------------------------------------------------------------------------------------------


                     Table 9--Average Distances to Level B Threshold (stationary and mobile)
                                                    [120 dB]
----------------------------------------------------------------------------------------------------------------
                                                         Average distance to 120 dB threshold
                                                                         (m)                     Season average
                       Waypoint                        ---------------------------------------    distance to
                                                            May          July       October      threshold  (m)
----------------------------------------------------------------------------------------------------------------
M1....................................................        4,215        3,911        4,352              4,159
M2....................................................        3,946        3,841        4,350              4,046
M3....................................................        4,156        3,971        4,458              4,195
M4....................................................        4,040        3,844        4,364              4,083
M5....................................................        4,053        3,676        4,304              4,011
M6....................................................        3,716        3,445        3,554              3,572
M7....................................................        2,947        2,753        2,898              2,866
M8....................................................        3,270        3,008        3,247              3,175
M9....................................................        3,567        3,359        3,727              3,551
M10...................................................        3,600        3,487        3,691              3,593
M11...................................................        3,746        3,579        4,214              3,846
M12...................................................        3,815        3,600        3,995              3,803
M13...................................................        4,010        3,831        4,338              4,060
M14...................................................        3,837        3,647        4,217              3,900
M15...................................................        3,966        3,798        4,455              4,073
M16...................................................        3,873        3,676        4,504              4,018
M18...................................................        5,562        3,893        4,626              4,694
M20...................................................        5,044        3,692        4,320              4,352
M22...................................................        4,717        3,553        4,067              4,112
M24...................................................        4,456        3,384        4,182              4,007
M25...................................................        3,842        3,686        4,218              3,915
M26...................................................        3,690        3,400        3,801              3,630
M27...................................................        3,707        3,497        3,711              3,638
M28...................................................        3,546        3,271        3,480              3,432
M29...................................................        3,618        3,279        3,646              3,514
                                                       ---------------------------------------------------------
    Average...........................................        3,958        3,563        4,029              3,850
----------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    Densities for marine mammals in Cook Inlet were derived from MML 
aerial surveys, typically flown in June,

[[Page 27617]]

from 2000 to 2018 (Rugh et al. 2005; Shelden et al. 2013, 2015, 2017, 
2019). A survey was also conducted in 2021 but density information is 
not yet available. While the surveys are concentrated for a few days in 
June annually, which may skew densities for seasonally present species, 
they are still the best available long-term dataset of marine mammal 
sightings available in Cook Inlet. Density was calculated by summing 
the total number of animals observed and dividing the number sighted by 
the area surveyed. The total number of animals observed accounts for 
both lower and upper Cook Inlet. There are no density estimates 
available for California sea lions in Cook Inlet, as they are so 
infrequently sighted. Densities are presented in Table 10 below.

           Table 10--Densities of Marine Mammals in Cook Inlet
------------------------------------------------------------------------
                                                               Density
                          Species                              (indiv/
                                                                km\2\)
------------------------------------------------------------------------
Humpback whale.............................................     0.001770
Minke whale................................................     0.000009
Gray whale.................................................     0.000075
Fin whale..................................................     0.000311
Killer whale...............................................     0.000601
Beluga whale (MML lower CI)................................     0.000023
Beluga whale (MML middle CI)...............................     0.001110
Goetz beluga--LCI..........................................     0.011106
Goetz beluga--NCI..........................................     0.001664
Goetz beluga--TB...........................................     0.015053
Dall's porpoise............................................     0.000154
Harbor porpoise............................................     0.004386
Harbor seal................................................     0.241401
Steller sea lion...........................................     0.007609
California sea lion........................................     0.000000
------------------------------------------------------------------------

    For beluga whales, two densities were considered as a comparison of 
available data. The first source considered was directly from the MML 
aerial surveys, as described above. Sighting data collected during 
aerial surveys is collected and then several correction factors are 
applied to address perception, availability, and proximity bias. These 
corrected sightings totals are then divided by the total area covered 
during the survey to arrive at a density value. Densities were derived 
for the entirety of Cook Inlet as well as for middle and lower Cook 
Inlet. Densities across all three regions are low and there is a known 
effect of seasonality on the distribution of the whales. Thus, 
densities derived directly from surveys flown in June might 
underestimate the density of beluga whales in lower Cook Inlet at other 
ice-free times of the year.
    The other mechanism for arriving at beluga whale density considered 
here is the Goetz et al. (2012) habitat-based model. This model is 
derived from sightings and incorporates depth soundings, coastal 
substrate type, environmental sensitivity index, anthropogenic 
disturbance, and anadromous fish streams to predict densities 
throughout Cook Inlet. The output of this model is a beluga density map 
of Cook Inlet, which predicts spatially explicit density estimates for 
Cook Inlet belugas. Using the resulting grid densities, average 
densities were calculated for two regions applicable to Hilcorp's 
operations. The densities applicable to the area of activity (i.e., the 
North Cook Inlet Unit density for middle Cook Inlet activities and the 
Trading Bay density for activities in Trading Bay) are provided in 
Table 11 below and were carried forward to the exposure estimates. 
Likewise, when a range is given, the higher end of the range was used 
out of caution to calculate exposure estimates (i.e., Trading Bay in 
the Goetz model has a range of 0.004453 to 0.015053; 0.015053 was used 
for the exposure estimates).

Table 11--Cook Inlet Beluga Whale Densities Based on Goetz et al. (2012)
                              Habitat Model
------------------------------------------------------------------------
                                                           Beluga whale
                    Project location                      density  (ind/
                                                              km\2\)
------------------------------------------------------------------------
North Cook Inlet Unit (middle Cook Inlet)...............        0.001664
Trading Bay Area........................................  0.004453-0.015
                                                                     053
------------------------------------------------------------------------

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate for each of the two 
IHAs.
    Year 1 IHA--As described above, Hilcorp's tug towing rig activity 
was divided into two portions for the purpose of take estimation: 
Stationary and mobile activity. For stationary activity, five hours of 
sound production per day was assumed for up to 16 days (eight moves or 
segments consisting of two days each). For the mobile portion of the 
activity, two days of nine hours of mobile activity (assuming a source 
velocity of 2.06 m/s) and six days of six hours of mobile activity were 
assumed, for a total of eight rig moves.
    Year 2 IHA--For stationary activity, 5 hours of sound production 
per day was assumed for up to 16 days. For mobile activity, 9 hours of 
sound production was assumed for 2 days, as well as 6 hours of sound 
production for 6 days, for a total of eight rig moves.
    The ensonified areas calculated per activity type (stationary and 
mobile) for a single day were multiplied by marine mammal densities to 
get an estimate of exposures per day. This was then multiplied by the 
number of days of that type of activity (stationary or mobile) to 
arrive at the number of estimated exposures per year per activity type. 
These exposures by activity type were then summed to result in a number 
of exposures per year for all tug towing rig activity. The estimated 
exposures are provided below in Tables 12 and 13 for Year 1 and Year 2 
of activity, respectively. The calculated exposures for Years 1 and 2 
are identical, as the number of days and hours of expected tug noise is 
ultimately the same despite the different divisions of the activity 
(e.g. Year 1 has tug noise from P&A, Year 2 does not have P&A but has 
more overall tugging trips). There are two estimates for beluga whales 
provided in the tables below to demonstrate the difference in the 
calculations based on the chosen density value. As exposure estimates 
were calculated based on specific potential rig moves or well 
locations, the density value for beluga whales that was carried through 
the estimate was the higher density value for that particular location. 
There are no estimated exposures based on this method of calculation 
for California sea lions because the assumed density is 0.00 animals/
km\2\.

                                 Table 12--Total Calculated Exposures for Year 1
----------------------------------------------------------------------------------------------------------------
                     Group                                   Species                  Level A         Level B
----------------------------------------------------------------------------------------------------------------
LF Cetaceans..................................  Humpback whale..................           0.000           4.058
                                                Minke whale.....................           0.000           0.021
                                                Gray whale......................           0.000           0.171
                                                Fin whale.......................           0.000           0.712
MF Cetaceans..................................  Killer whale....................           0.000           1.379
                                                Beluga whale NMFS...............           0.000           2.545
                                                Beluga whale Goetz..............           0.000          10.345

[[Page 27618]]

 
HF Cetaceans..................................  Dall's porpoise.................           0.001           0.353
                                                Harbor porpoise.................           0.038          10.057
Phocids.......................................  Harbor seal.....................           0.012         553.565
Otariids......................................  Steller sea lion................           0.000          17.448
                                                California sea lion.............           0.000           0.000
----------------------------------------------------------------------------------------------------------------


                                 Table 13--Total Calculated Exposures for Year 2
----------------------------------------------------------------------------------------------------------------
                     Group                                   Species                  Level A         Level B
----------------------------------------------------------------------------------------------------------------
LF Cetaceans..................................  Humpback whale..................           0.000           4.058
                                                Minke whale.....................           0.000           0.021
                                                Gray whale......................           0.000           0.171
                                                Fin whale.......................           0.000           0.712
MF Cetaceans..................................  Killer whale....................           0.000           1.379
                                                Beluga whale NMFS...............           0.000           2.545
                                                Beluga whale Goetz..............           0.000          11.651
HF Cetaceans..................................  Dall's porpoise.................           0.001           0.353
                                                Harbor porpoise.................           0.038          10.057
Phocids.......................................  Harbor seal.....................           0.012         553.565
Otariids......................................  Steller sea lion................           0.000          17.448
                                                California sea lion.............           0.000           0.000
----------------------------------------------------------------------------------------------------------------

    Based on the analysis described above, NMFS does not propose to 
authorize take via Level A harassment related to Hilcorp's tug towing 
drill rig activity. For mobile tugging, the distances to the PTS 
thresholds for high frequency cetaceans (the only functional hearing 
group of concern based on the model results) are smaller than the 
overall size of the tug and rig configuration, making it unlikely a 
cetacean would remain close enough to the tug engines to incur PTS. For 
stationary positioning of the jack up rig, the PTS isopleths are up to 
679 m for high frequency cetaceans, but calculated on the assumption 
that an animal would remain within several hundred meters of the jack-
up rig for the full five hours of noise-producing activity. Given the 
location of the activity is not in an area known to be essential 
habitat for any marine mammal species with extreme site fidelity over 
the course of two days, the occurrence of PTS is unlikely. A table 
indicating the number of takes, by Level B harassment, proposed to be 
authorized is provided below.

 Table 14--Takes (by Level B Harassment) Calculated and Proposed To Be Authorized for Year 1 IHA and Year 2 IHA
----------------------------------------------------------------------------------------------------------------
                                                      Year 1          Year 1          Year 2          Year 2
                                                    calculated      authorized      calculated      authorized
----------------------------------------------------------------------------------------------------------------
Humpback whale..................................           4.058               6           4.058               6
Minke whale.....................................           0.021               6           0.021               6
Gray whale......................................           0.171               2           0.171               2
Fin whale.......................................           0.712               4           0.712               4
Killer whale....................................           1.379              10           1.379              10
Beluga whale....................................     2.545 (MML)              22     2.545 (MML)              22
                                                  10.345 (Goetz)                  11.651 (Goetz)
Dall's porpoise.................................           0.353               6           0.353               6
Harbor porpoise.................................          10.057              44          10.057              44
Harbor seal.....................................         553.565             554         553.565             554
Steller sea lion................................          17.448              17          17.448              17
California sea lion.............................               0               2               0               2
----------------------------------------------------------------------------------------------------------------

    As illustrated by the table above, the estimated exposures for 
several species are less than one. While uncommon, these species have 
been previously sighted in Cook Inlet and some are unlikely to appear 
as solitary individuals when sighted. For humpback whales, the number 
of takes proposed to be authorized is increased from the calculated 
estimate of four to six individuals. There were two sightings of three 
humpback whales observed near Ladd Landing north of the Forelands 
during the Harvest Alaska CIPL project (Sitkiewicz et al. 2018). Based 
on documented observations during the CIPL survey (the survey nearest 
the Action Area), Hilcorp is requesting six takes of humpback whales to 
allow for up to two sightings of three individuals, consistent with 
what was observed during the CIPL project. Minke whale takes proposed 
to be authorized are increased from the calculated less than one 
individual to five. Minke whales are commonly sighted in groups of two 
or three, as well as sightings of individuals. There were eight 
sightings of eight minke whales observed during the 2019 Hilcorp lower 
Cook Inlet seismic survey (Fairweather Science 2020). As the occurrence 
of minke whales is expected to be less in middle Cook Inlet than lower 
Cook Inlet and considering the observed group sizes, Hilcorp is

[[Page 27619]]

requesting six takes of minke whale to allow for the possibility of two 
sightings of a group of three individuals. During Apache's 2012 seismic 
program, nine gray whales were observed in June and July (Lomac-MacNair 
et al. 2013). During Apache's seismic program in 2014, one gray whale 
was observed (Lomac-MacNair et al. 2014). During SAExploration's 
seismic survey in 2015, the 2018 CIPL project, and Hilcorp's 2019 
seismic survey, no gray whales were observed (Kendall et al. 2015; 
Sitkiewicz et al. 2018; Fairweather Science 2020). Considering the 
Action Area is in middle Cook Inlet where sightings of gray whales are 
less common, Hilcorp is requesting two takes of gray whales to allow 
for the potential occurrence of two individual gray whales. The number 
of fin whale takes proposed to be authorized is increased from one to 
four individuals, as they may be seen in groups of two to seven 
individuals. During seismic surveys conducted in 2019 by Hilcorp in the 
lower Cook Inlet, fin whales were recorded in groups ranging in size 
from one to 15 individuals (Fairweather 2020). During the NMFS aerial 
surveys in Cook Inlet from 2000 to 2018, 10 sightings of 26 estimated 
individual fin whales in lower Cook Inlet were observed (Shelden et al. 
2013, 2015, 2016, 2019). A total authorized take of four fin whales 
would account for two sightings of two animals, which is the lower end 
of the range of common group size.
    The number of proposed killer whale takes is increased to ten from 
the calculated exposure of one. Killer whales are typically sighted in 
pods of a few animals to 20 or more (NOAA 2022b). During seismic 
surveys conducted in 2019 by Hilcorp in the lower Cook Inlet, 21 killer 
whales were observed, either as single individuals or in groups ranging 
in size from two to five individuals (Fairweather 2020). Based on 
documented sightings, Hilcorp requests ten takes of killer whales to 
allow for two sightings with a group size of five individuals. 
Depending on the density data used for each activity, the estimated 
annual exposures for beluga whales is three to 10 animals. The proposed 
number of takes to be authorized for beluga whales is 22 animals to 
allow for the possibility that more than one observation of typical 
Cook Inlet beluga groups occurs. The 2018 MML aerial survey (Shelden 
and Wade, 2019) estimated a median group size of approximately 11 
beluga whales, although group sizes were highly variable (two to 147 
whales) as was the case in previous survey years (Boyd et al. 2019). 
Additionally, vessel-based surveys in 2019 observed beluga whale groups 
in the Susitna River Delta (roughly 24 km [15 miles] north of the 
Tyonek Platform) that ranged from 5 to 200 animals (McGuire et al. 
2021). The very large groups seen in the Susitna River Delta are not 
expected near Hilcorp's platforms, however, smaller groups (i.e., 
around the median group size) could be traveling through to access the 
Susitna River Delta and other nearby coastal locations, particularly in 
the shoulder seasons when belugas are more likely to occur in middle 
Cook Inlet. The number of Dall's porpoise takes proposed to be 
authorized is increased from less than one estimated individual to six. 
Dall's porpoises are usually found in groups averaging between two and 
12 individuals (NOAA 2022c). During seismic surveys conducted in 2019 
by Hilcorp in the lower Cook Inlet, Dall's porpoises were recorded in 
groups ranging in size from two to seven individuals (Fairweather 
2020). The 2012 Apache survey recorded two groups of three individual 
Dall's porpoises (Lomac-MacNair 2014). Because occurrence of Dall's 
porpoise is anticipated to be less in middle Cook Inlet than lower Cook 
Inlet, the smaller end of documented group sizes (three individuals) is 
used, and Hilcorp requests six takes of Dall's porpoise to allow for 
two sightings of three individuals similar to the numbers observed 
during the 2012 Apache survey. Harbor porpoise takes are proposed to be 
increased from an estimated 10 takes to 44 takes. Shelden et al. (2014) 
compiled historical sightings of harbor porpoises from lower to upper 
Cook Inlet that spanned from a few animals to 92 individuals. The 2018 
CIPL project that occurred just north of the Action Area in Cook Inlet 
reported 29 sightings of 44 individuals (Sitkiewicz et al. 2018). While 
the duration of days that the tugs are towing a jack-up rig will be 
less than the CIPL project, given the increase in sightings of harbor 
porpoise in recent years and the inability to shut down the tugs, 
Hilcorp request 44 takes of harbor porpoise, commensurate with the 
number observed in the nearby CIPL project.
    Calculated take of California sea lions was zero because the 
assumed density in Cook Inlet is zero. Any potential sightings would 
likely be of lone out of habitat individuals. Two solitary individuals 
were seen during the 2012 Apache seismic survey in Cook Inlet (Lomac-
MacNair et al. 2013). Two takes are requested based on the potential 
that two lone animals could be sighted over a year of work, as was seen 
during Apache's year of work.

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)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat, as 
well as subsistence uses. This considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range). It further 
considers the likelihood that the measure will be effective if 
implemented (probability of accomplishing the mitigating result if 
implemented as planned), the likelihood of effective implementation 
(probability implemented as planned), and;
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.

Mitigation for Marine Mammals and Their Habitat

    NMFS anticipates the project, in both of the two IHAs, will create 
an acoustic footprint above ambient sound levels of approximately 45 
km\2\ around the tugs positioning the jack-up rig or for approximately 
7 km in all directions along a towing trajectory of approximately 37km. 
There is a

[[Page 27620]]

discountable potential for marine mammals to incur PTS from the 
project, as source levels are relatively low, non-impulsive, and 
animals would have to remain at very close distances for multiple hours 
to accumulate acoustic energy at levels that could damage hearing. 
Therefore, we do not believe there is potential for Level A harassment 
and there is no designated shut-down/exclusion zone proposed for this 
project. However, Hilcorp will implement a number of mitigation 
measures designed to reduce the potential for and severity of Level B 
harassment and minimize the acoustic footprint of the project.
    The tugs towing a jack-up rig are not able to shutdown while 
transiting or positioning the rig. Hilcorp will maneuver the tugs 
towing the jack-up rig such that they maintain a consistent speed 
(approximately 4 knots) and avoid multiple changes of speed and 
direction to make the course of the vessels as predictable as possible 
to marine mammals in the surrounding environment, characteristics that 
are expected to be associated with a lower likelihood of disturbance. 
Hilcorp proposes to implement a clearance zone of 1,500 meters around 
the centerpoint of the three tug configuration and will employ two 
NMFS-approved protected species observers (PSOs) to conduct marine 
mammal monitoring for all mobile and stationary activity involving tugs 
towing attached to the jack-up rig. Prior to commencing activities 
during daylight hours or if there is a 30-minute lapse in operational 
activities, the PSOs will monitor the clearance zone for marine mammals 
for 30 minutes. If no marine mammals are observed, operations may 
commence. If a marine mammal(s) is observed within the clearance zone 
during the clearing, the PSOs will continue to watch until either: (1) 
The animal(s) is outside of and on a path away from the clearance zone; 
or (2) 15 minutes have elapsed if the species was a pinniped or small 
cetacean, or 30 minutes for large cetaceans whales. Once the PSOs have 
determined one of those conditions are met, operations may commence.
    Should a marine mammal be observed during towing or positioning, 
the PSOs will monitor and carefully record any reactions observed until 
the jack-up rig has reached its intended position. No new operational 
activities would be started until the animal leaves the area. PSOs will 
also collect behavioral information on marine mammals sighted during 
monitoring efforts.
    Hilcorp will make every effort to operate with the tide, resulting 
in a low power output from the tugs towing the jack-up rig. If human 
safety or equipment integrity is at risk, Hilcorp may necessarily 
operate in an unfavorable tidal state. Due to the nature of tidal 
cycles in Cook Inlet, it is possible the most favorable tide for the 
towing operation will occur during nighttime hours. Hilcorp will 
operate the tugs towing the jack-up rigs at night if the nighttime 
operations result in a lower power output from the tugs by operating 
with a favorable tide.
    In low-light conditions, night-vision devices shown to be effective 
at detecting marine mammals in low-light conditions (e.g., Armasight by 
FLIR Command Pro[supreg], or similar) will be provided to PSOs to aid 
in low-light visibility. Every effort will be made to observe that the 
clearance zone is free of marine mammals by using night-vision devices, 
however it may not always be possible to see and clear the entire 
clearance zone prior to nighttime transport. PSOs will monitor the 
greatest extent feasible for 30 minutes immediately prior to the start 
of load bearing activities. If no marine mammals are observed, 
operations may commence. If a marine mammal is observed within the 
during the clearing, the PSOs will continue to watch until either: (1) 
The animal(s) is outside of and on a path away from the clearance zone; 
or (2) 15 minutes have elapsed if the species was a pinniped or small 
cetacean, or 30 minutes for large cetaceans whales. Once the PSOs have 
determined one of those conditions are met, operations may commence.
    Out of concern for potential disturbance to Cook Inlet beluga 
whales in sensitive and essential habitat, Hilcorp will not conduct 
noise-producing activity within 16 km (10 miles) of the mean high-high 
water line of the Susitna River Delta (Beluga River to the Little 
Susitna River) between April 15 and October 15.
    Based on our evaluation of the applicant's proposed measures, for 
both IHAs, NMFS has preliminarily determined that the proposed 
mitigation measures provide the means of effecting the least 
practicable impact on the affected species or stocks and their habitat, 
paying particular attention to rookeries, mating grounds, and areas of 
similar significance and on the availability of such species or stock 
for subsistence uses.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. 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:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density).
    <bullet> Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas).
    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors.
    <bullet> How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks.
    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat).
    <bullet> Mitigation and monitoring effectiveness.
    Hilcorp will abide by all monitoring and reporting measures 
contained within their Marine Mammal Monitoring and Mitigation Plan, 
dated February 25, 2022. A summary of those measures and additional 
requirements proposed by NMFS is provided below.
    A minimum of two NMFS-approved PSOs will be on-watch during all 
activities wherein the jack-up rig is attached to the tugs for the 
duration of the project. Minimum requirements for a PSO include:
    (a) Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the

[[Page 27621]]

water's surface with ability to estimate target size and distance; use 
of binoculars may be necessary to correctly identify the target;
    (b) Advanced education in biological science or related field 
(undergraduate degree or higher required);
    (c) Experience and ability to conduct field observations and 
collect data according to assigned protocols (this may include academic 
experience);
    (d) Experience or training in the field identification of marine 
mammals, including the identification of behaviors;
    (e) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    (f) Writing skills sufficient to prepare a report of observations 
including but not limited to the number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates and times when in-water construction activities were 
suspended to avoid potential incidental injury from construction sound 
of marine mammals observed within a defined shutdown zone; and marine 
mammal behavior; and
    (g) Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    PSOs will be stationed aboard a tug or the jack-up rig, work in 
shifts lasting no more than four hours without a minimum of a one hour 
break, and will not be on-watch for more than 12 hours within a 24-hour 
period.
    Hilcorp will submit monthly reports for all months in which tugs 
towing or positioning the jack-up rig occurs. A draft marine mammal 
monitoring report would be submitted to NMFS within 90 days after the 
completion of the tug towing jack-up rig activities for the year. It 
will include an overall description of work completed, a narrative 
regarding marine mammal sightings, and associated marine mammal 
observation data sheets. Specifically, the report must include:
    <bullet> Date and time that monitored activity begins or ends;
    <bullet> Construction activities occurring during each observation 
period;
    <bullet> Weather parameters (e.g., percent cover, visibility);
    <bullet> Water conditions (e.g., sea state, tide state);
    <bullet> Species, numbers, and, if possible, sex and age class of 
marine mammals;
    <bullet> Description of any observable marine mammal behavior 
patterns, including bearing and direction of travel and distance from 
pile driving activity;
    <bullet> Distance from pile driving activities to marine mammals 
and distance from the marine mammals to the observation point;
    <bullet> Locations of all marine mammal observations; and
    <bullet> Other human activity in the area.
    If no comments are received from NMFS within 30 days, the draft 
final report will constitute the final report. If NMFS submits 
comments, Hilcorp will submit a final report addressing NMFS comments 
within 30 days after receipt of comments.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHAs 
(if issued), such as an injury, serious injury or mortality, Hilcorp 
would immediately cease the specified activities and report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, and the Alaska Regional Stranding 
Coordinator. The report would include the following information:
    <bullet> Description of the incident;
    <bullet> Environmental conditions (e.g., Beaufort sea state, 
visibility);
    <bullet> Description of all marine mammal observations in the 24 
hours preceding the incident;
    <bullet> Species identification or description of the animal(s) 
involved;
    <bullet> Fate of the animal(s); and
    <bullet> Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with Hilcorp to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. Hilcorp would not be able 
to resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that Hilcorp discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition as described in the next paragraph), 
Hilcorp would immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the NMFS Alaska Stranding Hotline and/or by email to the Alaska 
Regional Stranding Coordinator. The report would include the same 
information identified in the paragraph above. Activities would be able 
to continue while NMFS reviews the circumstances of the incident. NMFS 
would work with Hilcorp to determine whether modifications in the 
activities are appropriate.
    In the event that Hilcorp discovers an injured or dead marine 
mammal and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in the IHAs 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), Hilcorp would report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or 
by email to the Alaska Regional Stranding Coordinator, within 24 hours 
of the discovery. Hilcorp would provide photographs or video footage 
(if available) or other documentation of the stranded animal sighting 
to NMFS and the Marine Mammal Stranding Network.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338; 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, the discussion of our analysis applies to all 
the species

[[Page 27622]]

listed in Table 15, given that the anticipated effects of this activity 
on these different marine mammal stocks are expected to be similar. 
There is little information about the nature or severity of the 
impacts, or the size, status, or structure of any of these species or 
stocks that would lead to a different analysis for this activity.
    To avoid repetition, this introductory section of our analysis 
applies to all the species listed in Table 15, given that many of the 
anticipated effects of this project on different marine mammal stocks 
are expected to be relatively similar in nature. 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.
    Potential impacts to marine mammal habitat were discussed 
previously in this document (see Potential Effects of Specified 
Activities on Marine Mammals and their Habitat). Marine mammal habitat 
may be impacted by elevated sound levels, but these impacts would be 
temporary. In addition to being temporary and short in overall 
duration, the acoustic footprint of both years of the proposed activity 
is small relative to the overall distribution of the animals in the 
area and their use of the area. Feeding behavior is not likely to be 
significantly impacted, as no areas of biological significance for 
marine mammal feeding are known to exist in the project area and 
individual marine mammals are not expected to be exposed to the noise 
from the activities repeatedly or in long durations.
    The proposed project would create an acoustic footprint around the 
project area for a total of sixteen days per year from approximately 
April through October. Noise levels within the footprint would reach or 
exceed 120 dB rms. We anticipate the 120 dB footprint to be limited to 
no more than 45km\2\ around the tugs positioning the jackup rig or 
approximately 7 km in all directions along a towing trajectory of 
approximately 37 km. The habitat within the footprint is not heavily 
used by marine mammals during the project time frame (e.g., Cook Inlet 
beluga whale Critical Habitat Area 2, within which the activity 
resulting in the take of marine mammals is anticipated to potentially 
occur, is designated for beluga fall and winter use) and marine mammals 
are not known to engage in critical behaviors associated with this 
portion of Cook Inlet (e.g., no known breeding grounds, foraging 
habitat, etc.). Most animals will likely be transiting through the 
area; therefore, exposure would be brief. Animals may swim around the 
project area but we do not expect them to abandon any intended path. We 
also expect the number of animals exposed to be small relative to 
population sizes. Finally, Hilcorp will minimize potential exposure of 
marine mammals to elevated noise levels by not commencing operational 
activities if marine mammals are observed within the immediate starting 
area. Hilcorp is also able to reduce the impact of their activity by 
conducting tugging operations with favorable tides whenever feasible. 
In summary and as described above, the following factors primarily 
support our preliminary determinations that the impacts resulting from 
the activities described for these two IHAs are not expected to 
adversely affect the species or stock through effects on annual rates 
of recruitment or survival:
    <bullet> No mortality is anticipated or authorized.
    <bullet> The mobile portion of the project does not involve noise 
sources capable of inducing PTS in any species other than high 
frequency cetaceans;
    <bullet> Exposure would likely be brief given transiting behavior 
of marine mammals in the action area;
    <bullet> Marine mammal densities are low in the project area; 
therefore, there will not be substantial numbers of marine mammals 
exposed to the noise from the project compared to the affected 
population sizes; and
    <bullet> Hilcorp would monitor for marine mammals daily and 
minimize exposure to operational activities.
    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 described in the Year 1 IHA will 
have a negligible impact on all affected marine mammal species or 
stocks. Also, separately, NMFS preliminarily finds that the total 
marine mammal take from the proposed activity described in the Year 2 
IHA will have a negligible impact on all affected marine mammal species 
or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under sections 101(a)(5)(A) and (D) of the MMPA for 
specified activities other than military readiness activities. The MMPA 
does not define small numbers and so, in practice, where estimated 
numbers are available, NMFS compares the number of individuals taken to 
the most appropriate estimation of abundance of the relevant species or 
stock in our determination of whether an authorization is limited to 
small numbers of marine mammals. When the predicted number of 
individuals to be taken is fewer than one third of the species or stock 
abundance (as it is for all stocks in both the Year 1 and Year 2 IHAs), 
the take is considered to be of small numbers. Additionally, other 
qualitative factors may be considered in the analysis, such as the 
temporal or spatial scale of the activities.
    Table 15 provides the quantitative analysis informing our small 
numbers determinations for the Year 1 and Year 2 IHAs. For most 
species, the amount of take proposed represents less than approximately 
two percent of the population for each IHA. For beluga whales, the 
amount of take proposed represents slightly under eight percent of the 
population for each IHA.

              Table 15--Percent of Stock Proposed To Be Taken by Level B Harassment Under Each IHA
----------------------------------------------------------------------------------------------------------------
                                                                     Abundance     Proposed take    Percent of
                Species                           Stock               (Nbest)        (Level B)         stock
----------------------------------------------------------------------------------------------------------------
Year 1:
    Humpback whale....................  Western North Pacific...          11,571               6            0.05
    Minke whale.......................  Alaska..................           1,233               6            0.49
    Gray whale........................  Eastern Pacific.........          26,960               2            0.01
    Fin whale.........................  Northeastern Pacific....           2,554               4            0.16
    Killer whale......................  Alaska Resident Gulf of              587              10             1.7
                                         Alaska, Aleutian                  2,347                            0.43
                                         Islands, and Bering Sea
                                         Transient.
    Beluga whale......................  Cook Inlet..............             279              22            7.89

[[Page 27623]]

 
    Dall's porpoise...................  Alaska..................          83,400               6            0.01
    Harbor porpoise...................  Gulf of Alaska..........          31,046              44            0.14
    Harbor seal.......................  Cook Inlet/Shelikof.....          26,907             554            2.06
    Steller sea lion..................  Western.................          53,624              17            0.03
    California sea lion...............  U.S.....................         233,515               5            0.00
Year 2:
    Humpback whale....................  Western North Pacific...          11,571               6            0.05
    Minke whale.......................  Alaska..................           1,233               6            0.49
    Gray whale........................  Eastern Pacific.........          26,960               2            0.01
    Fin whale.........................  Northeastern Pacific....           2,554               4            0.16
    Killer whale......................  Alaska Resident Gulf of              587              10             1.7
                                         Alaska, Aleutian                                                   0.43
                                         Islands, and Bering Sea
                                         Transient.
    Beluga whale......................  Cook Inlet..............             279              22            7.89
    Dall's porpoise...................  Alaska..................          83,400               6            0.01
    Harbor porpoise...................  Gulf of Alaska..........          31,046              44            0.14
    Harbor seal.......................  Cook Inlet/Shelikof.....          26,907             554            2.06
    Steller sea lion..................  Western.................          53,624              17            0.03
    California sea lion...............  U.S.....................         233,515               2            0.00
----------------------------------------------------------------------------------------------------------------

    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks for the Year 1 IHA. Separately, NMFS 
also preliminarily finds that small numbers of marine mammals will be 
taken relative to the population size of the affected species or stocks 
for the Year 2 IHA.

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 
availability of such species or stock for taking for subsistence uses 
by Alaska 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.
    To further minimize any potential effects of their action on 
subsistence activities, Hilcorp has outlined their communication plan 
for engaging with subsistence users in their Stakeholder Engagement 
Plan (Appendix B of Hilcorp's application). Hilcorp will be required to 
abide by this plan and update the plan accordingly.
    Subsistence communities identified as project stakeholders near 
Hilcorp's middle Cook Inlet and Trading Bay activities include the 
Village of Salamatof and the Native Village of Tyonek. The ADF&G 
Community Subsistence Information System does not contain data for 
Salamatof. For the purposes of our analyses for the Year 1 and Year 2 
IHAs, we can assume the subsistence uses are similar to those of nearby 
communities such as Kenai. At 3.5 km away from the closest point of 
approach, Tyonek is the closest subsistence community to Hilcorp's 
proposed tug route. Tyonek, on the western side of lower Cook Inlet, 
has a subsistence harvest area that extends from the Susitna River 
south to Tuxedni Bay (BOEM 2016). In Tyonek, harbor seals were 
harvested between June and September by 6 percent of the households 
(Jones et al. 2015). Seals were harvested in several areas, 
encompassing an area stretching 32.2 km (20 miles) along the Cook Inlet 
coastline from the McArthur Flats north to the Beluga River. Seals were 
searched for or harvested in the Trading Bay areas as well as from the 
beach adjacent to Tyonek (Jones et al. 2015).
    Subsistence hunting of whales is not known to currently occur in 
Cook Inlet. Hilcorp's tug towing jack-up rig activities may overlap 
with subsistence hunting of seals. However, these activities typically 
occur along the shoreline or very close to shore near river mouths, 
whereas most of Hilcorp's tugging is in the middle of the Inlet and 
rarely near the shoreline or river mouths. Any harassment to harbor 
seals is anticipated to be short-term, mild, and not result in any 
abandonment or behaviors that would make the animals unavailable to 
Alaska Natives.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there will 
not be an unmitigable adverse impact on subsistence uses from 
Hilcorp's's proposed activities under the Year 1 IHA. Separately, NMFS 
has also preliminarily determined that there will not be an unmitigable 
adverse impact on subsistence uses from Hilcorp's proposed activities 
under the Year 2 IHA.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA; 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species, in this case with the Alaska Regional 
Protected Resources Division Office.
    NMFS is proposing to authorize take of humpback whales (Mexico DPS, 
Western North Pacific DPS), fin whales (Northeastern Pacific stock), 
beluga whales (Cook Inlet stock), and Steller

[[Page 27624]]

sea lion (Western DPS), which are listed under the ESA.
    The Permit and Conservation Division has requested initiation of 
Section 7 consultation with the NMFS Alaska Region for the issuance of 
these two IHAs. 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 two consecutive IHAs to Hilcorp for its tugs towing a jack-up rig 
in Cook Inlet in 2022-2023 and 2023-2024 open water seasons, provided 
the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. Drafts of the proposed IHAs can be found 
at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorizations, 
and any other aspect of this notice of proposed IHAs for the proposed 
tug towing jack-up rig activity. We also request at this time comment 
on the potential renewal of this proposed IHA as described in the 
paragraph below. Please include with your comments any supporting data 
or literature citations to help inform decisions on the request for 
this IHA or a subsequent Renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, one-year 
Renewal IHA following notice to the public providing an additional 15 
days for public comments when (1) up to another year of identical or 
nearly identical activities as described in the Description of Proposed 
Activities section of this notice is planned or (2) the activities as 
described in the Description of Proposed Activities section of this 
notice would not be completed by the time the IHA expires and a renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
    <bullet> A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that the 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
    <bullet> 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: May 4, 2022.
Kimberly Damon-Randall,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2022-09916 Filed 5-6-22; 8:45 am]
BILLING CODE 3510-22-P


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