[Federal Register Volume 85, Number 137 (Thursday, July 16, 2020)]
[Notices]
[Pages 43382-43412]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-15389]



[[Page 43381]]

Vol. 85

Thursday,

No. 137

July 16, 2020

Part IV





Department of Commerce





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National Oceanic and Atmospheric Administration





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Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to Construction of the Alaska LNG Project in 
Prudhoe Bay, Alaska; Notice

  Federal Register / Vol. 85, No. 137 / Thursday, July 16, 2020 / 
Notices  

[[Page 43382]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XA210]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Construction of the Alaska LNG 
Project in Prudhoe Bay, Alaska

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

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

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SUMMARY: NMFS has received a request from the Alaska Gasline 
Development Corporation (AGDC) for authorization to take marine mammals 
incidental to construction of the Alaska LNG Project in Prudhoe Bay, 
Alaska. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS is 
requesting comments on its proposal to issue an incidental harassment 
authorization (IHA) to incidentally take marine mammals during the 
specified activities. NMFS is also requesting comments on a possible 
one-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 August 
17, 2020.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Written comments should be sent to 
[email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Leah Davis, 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 issued or, if the taking is limited to harassment, a notice of a 
proposed incidental take authorization may be provided to the public 
for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for taking for subsistence uses 
(where relevant). Further, NMFS must prescribe the permissible methods 
of taking and other ``means of effecting the least practicable adverse 
impact'' on the affected species or stocks and their habitat, paying 
particular attention to rookeries, mating grounds, and areas of similar 
significance, and on the availability of the species or stocks for 
taking for certain subsistence uses (referred to in shorthand as 
``mitigation''); and requirements pertaining to the mitigation, 
monitoring and reporting of the takings are set forth.
    The definitions of all applicable MMPA statutory terms cited above 
are included in the relevant sections below.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to potential impacts 
on the human environment. Accordingly, NMFS plans to adopt the Federal 
Energy Regulatory Commission's (FERC) EIS, provided our independent 
evaluation of the document finds that it includes adequate information 
analyzing the effects on the human environment of issuing the IHA. NMFS 
is a cooperating agency on FERC's EIS.
    The FERC's EIS was made available for public comment from June 28, 
2019 to October 3, 2019. The FERC's Final EIS is available at https://www.ferc.gov/industries/gas/enviro/eis/2020/03-06-20-FEIS.asp.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On March 28, 2019, NMFS received a request from AGDC for an IHA to 
take marine mammals incidental to construction activities in Prudhoe 
Bay, Alaska. AGDC submitted revised applications on May 29, 2019; 
September 16, 2019; October 31, 2019, February 7, 2020; and February 
25, 2020. The application was deemed adequate and complete on May 21, 
2020. AGDC's request is for take of a small number of six species of 
marine mammals by harassment. Neither AGDC nor NMFS expects serious 
injury or mortality to result from this activity and, therefore, an IHA 
is appropriate.
    This proposed IHA would authorize incidental take during one year 
of the larger AK LNG project for which AGDC has also requested a five-
year Letter of Authorization (LOA) (84 FR 30991, June 28, 2019) for 
incidental take associated with project activities in Cook Inlet, 
Alaska. The larger project involves a pipeline that will span 
approximately 807 miles (mi) (1,290 kilometers [km]) from a gas 
treatment facility on Alaska's North Slope, which holds 35 trillion 
cubic feet (ft\3\) of proven gas reserves, to a liquefaction and export 
facility in southcentral Alaska.

Description of Proposed Activity

Overview

    AGDC plans to construct an integrated liquefied natural gas (LNG) 
project with interdependent facilities to liquefy supplies of natural 
gas from Alaska, in particular from the Point Thomson Unit (PTU) and 
Prudhoe Bay Unit (PBU)

[[Page 43383]]

production fields on the Alaska North Slope (North Slope), for export 
in foreign commerce and for in-state deliveries of natural gas. AGDC 
plans to construct an Alaska LNG Gas Treatment Plant (GTP), which they 
would construct with large, pre-fabricated modules that that can only 
be transported to the North Slope with barges (sealifts).
    AGDC is proposing to modify the existing West Dock causeway and 
associated dock heads in Prudhoe Bay, Alaska in order to facilitate 
offloading modular construction components and transporting them to the 
GTP construction site. Vibratory and impact pile driving associated 
with the work at West Dock would introduce underwater sound that may 
result in take by Level A and Level B harassment of marine mammals in 
Prudhoe Bay, Alaska. AGDC proposes to conduct pile driving up to 24 
hours per day on approximately 123 days from July through October 
during the open water (i.e., ice-free) season.

Dates and Duration

    The proposed IHA would be effective from July 1, 2022 to June 30, 
2023. Work that may result in the take of marine mammals is expected to 
take place during the open water season, between July and October, and 
would be conducted up to 24 hours per day, six days per week.
    Several communities on the North Slope of Alaska engage in 
subsistence hunting activities at varying times and in varying 
locations. These subsistence hunts are further described below in the 
Effects of Specified Activities on Subsistence Uses of Marine Mammals 
section. The proposed construction activities would occur closest to 
the marine subsistence use area used by the Native Village of Nuiqsut, 
which typically occurs August 25th to September 15th, or earlier if 
whaling is complete. AGDC will cease pile driving during the Nuiqsut 
whaling season.
    AGDC conservatively calculated that in-water construction would 
last 164 days. However, they expect that different pile types would be 
installed on the same day, which was not accounted for in the 164-day 
estimate. Therefore, given the information AGDC has provided NMFS, we 
expect that construction will require approximately 123 days of in-
water work considering the open water period, and the break in 
construction during the whaling season. If AGDC is not able to complete 
the work during the open water season construction period as planned, 
they will complete the work during a contingency period from late 
February to April 2023.

Specific Geographic Region

    The AK LNG construction activities at issue in this IHA will occur 
at West Dock in Prudhoe Bay, Alaska, on Alaska's North Slope. West Dock 
is a multipurpose facility, commonly used to offload marine cargo to 
support Prudhoe Bay oilfield development. West Dock extends out from 
the shoreline 2.7 miles (mi) (4.3 kilometers [km]) and is within 
shallow waters less than 14.2 feet (ft.) (4.3 meters [m]) deep. Please 
see Figure 1 in AGDC's application for a map of the West Dock area.

Detailed Description of Specific Activity

    Below, we discuss the proposed activities in Prudhoe Bay, a portion 
of the larger AK LNG project (which extends from the North Slope to 
Cook Inlet). For information on other AK LNG project components, please 
refer to Volume I, Chapter 2 of the Alaska LNG Final EIS.
    AGDC is proposing to further develop the West Dock facility in 
Prudhoe Bay, AK. West Dock is a multipurpose facility, commonly used to 
offload marine cargo to support Prudhoe Bay oilfield development. The 
West Dock causeway, which extends approximately 2.5 mi (4 km) into 
Prudhoe Bay from the shoreline, is a solid-fill gravel causeway 
structure. There are two existing loading docks along the causeway, 
referred to as Dock Head 2 (DH2) and Dock Head 3 (DH3), and a seawater 
treatment plant (STP) at the seaward terminus of the structure. A 650-
ft (198-m) breach with a single lane bridge was installed in the 
causeway between DH2 and DH3 during 1995 and 1996 due to concerns that 
the solid causeway was affecting coastal circulation and marine 
resources.
    Development of the dock facility would require constructing a new 
dock head referred to as Dock Head 4 (DH4), widening the gravel 
causeway between the proposed DH4 site and the onshore road system, and 
installation of a temporary barge bridge parallel to the existing 
bridge over the aforementioned breach to accommodate transport of the 
modules over the breach. The following describes these activities in 
detail.
    Causeway Widening--AGDC will build a parallel causeway 
approximately 100-125 ft (30.5-38.1 m) wide and 5,000 ft. long (1,524 
m) on the east side of the existing causeway from DH3 to DH4. AGDC will 
upgrade the other two existing segments of West Dock causeway to a 
width of approximately 100-125 ft (30.5-38.1 m) from the current width 
of 40-80 ft. (12.2-24.4 m). AGDC will conduct the widening on the east 
side of the causeway because there is a pipeline along the west side. 
The widening would occur along approximately 4,500 ft. (1,372 m) from 
DH3 to DH2, and 3,800 ft. (1,158 m) from DH2 to land. This causeway 
widening work would be conducted during the summer (July-August). 
Gravel would be hauled in by truck and deposited in place by shore-
based heavy equipment. Expected gravel requirements are indicated in 
Table 2 of AGDC's application. NMFS does not expect gravel deposition 
to result in take, and therefore, we do not discuss it further in this 
notice.
    DH4 Work Area and Bulkhead--AGDC will construct a new dock head 
(DH4). DH4 would be a gravity-based structure, with a combi-wall (sheet 
piles connected by H-piles) bulkhead or dock face back-filled with 
gravel. The gravel dock head would provide a working area of 
approximately 31 acres (0.13 km\2\) and would have five cargo berths. 
Gravel would be hauled in by truck and deposited in place by shore-
based heavy equipment. Hauling and placement of gravel for construction 
of DH4 would occur from June-September. Gravel requirements are 
quantified in Table 3 of AGDC's application.
    Construction of DH4 would require the installation of over 1,080 
linear ft. (329 m) of combi-wall forming a bulkhead at the dock face, 
and will require vibratory and impact pile driving. Other margins of 
the dock head would be sloped and armored with sand bags. Table 1 
indicates the planned numbers and types of piles proposed for 
installation, and proposed installation method for DH4 work, including 
the work area and bulkhead.

             Table 1--Piles Planned for Installation at DH4
------------------------------------------------------------------------
                                                             Number of
          Pile type/size             Installation method       piles
------------------------------------------------------------------------
11.5-inch Steel H-Pile............  Impact..............             212
48-inch Steel Pipe Pile...........  Impact..............              12

[[Page 43384]]

 
25-inch Steel Sheet Pile..........  Vibratory...........             422
14-inch Steel H-Pile (temporary)..  Vibratory...........              48
------------------------------------------------------------------------

    AGDC plans to construct DH4 from June-October (open water season). 
Hauling and placing of the gravel will take place first. AGDC plans to 
install the combi-wall mid-September-October (after the whaling season 
and before ice). If AGDC is not able to complete the DH4 construction 
during the open water season, they plan to complete construction during 
a contingency period from February to April 2023, working off the ice.
    DH4 Mooring Dolphins--AGDC plans to install twelve mooring dolphins 
in the cargo berths at the proposed DH4 to hold the ballasted barges in 
place. Figure 5 of AGDC's application shows the locations of the 
proposed mooring dolphins. AGDC plans to install four temporary spuds 
(14-inch steel H piles) for support prior to the construction of each 
mooring dolphin using a vibratory hammer. AGDC would extract these 
piles immediately after completion of the dolphin. Table 1 lists the 
proposed pile types, numbers, and driving methods for DH4 work, 
including the mooring dolphins.
    AGDC plans to install the mooring dolphins from September-October 
(after the Nuiqsut whaling season and before ice cover). If AGDC is not 
able to complete mooring dolphin construction during this time, they 
plan to complete construction during a contingency period from late 
February to April of the following year.
    Berthing Basin--The proposed location of the DH4 bulkhead is 
approximately 1,000 ft. (305 m) beyond the end of the existing causeway 
at the STP. This location was selected as it provides an existing 
nominal water depth of -12 ft. (-3.7 m) mean lower low water (MLLW) 
across the length of the bulkhead, allowing for berthing of cargo 
barges at their intended transit draft of 10 ft. (3.05 m) without the 
exchange of ballast water.
    AGDC plans to conduct screeding over the seafloor within the 
berthing area to a depth of -12 ft. (-3.7 m) MLLW. Screeding would 
redistribute the seabed materials to provide a flat and even surface on 
which the module cargo barges can be grounded. The berthing area 
encompasses approximately 13.7 acres (0.06 km\2\). In the screeding 
process, a tug and/or barge pushes or drags a beam or blade across the 
seafloor, removing high spots and filling local depressions. The 
screeding operation is not intended to increase or decrease overall 
seabed elevation so there would be no excavated materials requiring 
disposal.
    AGDC would conduct screeding in the summer immediately prior to 
arrival of each sealift and as soon as sea ice conditions allow 
mobilization of the screeding barge. Based on historical ice data, AGDC 
anticipates screeding during July for a period of up to 14 days. AGDC 
would conduct a multi-beam hydrographic survey to identify high and low 
spots in the seabed prior to each season with equipment emitting sound 
at frequencies above 200 kilohertz (kHz). We do not expect the survey 
to result in take, and we do not discuss it further in this notice. 
Additionally, we do not expect screeding to result in take of marine 
mammals, given that it is a continuous noise source comparable to other 
general construction activities. The Biological Opinion issued by NMFS' 
Alaska Regional Office conservatively requires AGDC to shut down at 215 
m during screeding operations. AGDC has not requested, and NMFS does 
not propose to authorize take incidental to the proposed screeding.
    Barge Bridge--The existing bridge over the aforementioned 650 ft. 
(198 m) breach in the causeway is too narrow for module transport and 
incapable of supporting the weight of the project modules. Therefore, 
AGDC plans to construct a temporary barge bridge to accommodate 
transport of the modules over the breach and to the onshore road 
system. AGDC plans to construct new sheet pile and gravel abutments 
along the east side of the existing bridge and plans to install four 
mooring dolphins. Two barges would then be placed along these mooring 
dolphins and between the abutments to form a temporary bridge for 
module transport.
    Sealifts and barge bridge installation and removal (not including 
pile driving) would occur each of six consecutive years to accommodate 
the modules required for the project. AGDC would construct the approach 
abutments and mooring dolphins (each further described below) in the 
first season, and would prepare the seabed before installation of the 
barge bridge for the first sealift. The barge bridge would be installed 
annually each sealift year at the beginning of the open-water season, 
and would be removed each fall prior to freeze-up. This installation 
and removal does not include installation and removal of the mooring 
dolphins. AGDC expects to conduct some seabed preparation prior to 
installation and use of the barge bridge in each subsequent sealift 
year. NMFS does not expect annual placement, use, or removal of the 
barge bridge or the seabed preparation to result in marine mammal 
harassment, and therefore we do not discuss it further in this notice.
    Barge Bridge Abutments--AGDC plans to construct approach abutments 
(gravel filled open-cell sheet pile bulkheads) along the east side of 
the existing causeway on both ends of the barge bridge. AGDC would 
place gravel bags for erosion control in locations where there is no 
bulkhead. The bulkheads would be approximately 420 ft. (128 m) long 
(along the causeway) and 120 ft. (36.6 m) across.
    Much of the abutment sheet pile is for the tail walls that run from 
the bulkhead into the gravel fill and terminate at an anchor pile (H-
pile). A large portion of this tail wall piling and many of the tail 
wall anchor piles would be driven into dry ground and are not included 
in the analysis for assessing in-water noise impacts on marine mammals. 
Table 2 lists the numbers and types of pilings planned for in-water 
installation for the barge bridge abutments.

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 Table 2--Piles Planned for In-Water Installation at the North and South
                     Barge Bridge Abutment Bulkheads
------------------------------------------------------------------------
                                      Pile type and          Number of
                                   installation method         piles
------------------------------------------------------------------------
South Abutment.................  19.69-inch Steel Sheet              695
                                  Pile (Vibratory).
                                 14-inch Steel H-Pile                  4
                                  (Impact).
North Abutment.................  19.69-inch Steel Sheet              609
                                  Pile (Vibratory).
                                 14-inch Steel H-Pile                  4
                                  (Impact).
------------------------------------------------------------------------

    AGDC plans to install the sheet piles from land or barges on open 
water, and potentially from the ice if the contingency period is 
necessary.
    Construction of the barge bridge abutments is scheduled for July-
August with a break in pile driving during the Nuiqsut whaling season 
(approximately August 25-September 15) if activities overlap. If AGDC 
is unable to complete construction during the open water period, they 
plan to complete the work during the contingency period from February 
to April of 2023.
    Barge Bridge Mooring Dolphins--AGDC plans to install four mooring 
dolphins at the barge bridge site to protect the current bridge from 
the barges and hold the ballasted barges in place. Each mooring dolphin 
consists of one 48-inch diameter (1.2 m), 100 ft. (30.5 m) long steel 
pipe pile that AGDC will drive with an impact hammer to a minimum of 65 
ft. (19.8 m) into the seabed. As described above for the DH4 mooring 
dolphins, AGDC plans to install four temporary spuds (14.5-inch steel 
H-piles) with a vibratory hammer for support prior to the construction 
of each barge bridge mooring dolphin. AGDC would extract these 
temporary spuds immediately after completion of the dolphin.
    AGDC plans to construct the barge bridge abutments, including the 
mooring dolphins, in July and August, with a break in pile driving 
during the Nuiqsut whaling season (approximately August 25-September 
15). If AGDC is not able to complete the work during that period, they 
will complete the dolphin installation during the contingency period 
from February to April of 2023.

  Table 3--Piles Planned for Mooring Dolphin Installation at the Barge
                            Bridge Abutments
------------------------------------------------------------------------
                                                             Number of
             Pile type               Installation method       piles
------------------------------------------------------------------------
48-inch Steel Pipe Pile...........  Impact..............               4
14-inch Steel H-Pile (Temporary)..  Vibratory...........          \a\ 16
------------------------------------------------------------------------
\a\ Each of these piles will be installed and later removed after
  installation of mooring dolphin.


 Table 4--Total Number of Piles Among All Prudhoe Bay Project Components
------------------------------------------------------------------------
                                                             Number of
        Pile size and type               Hammer type           piles
------------------------------------------------------------------------
11.5-inch H-Pile..................  Impact..............             212
14.5-inch H-Pile..................  Impact..............               8
                                    Vibratory...........              64
48-inch Pipe Pile.................  Impact..............              16
Sheet Piles (19.69-inch and 25-     Vibratory...........           1,726
 inch).
------------------------------------------------------------------------

    AGDC will only operate one hammer at a time during all pile 
driving.
    Seabed Preparation at the Barge Bridge--AGDC will construct a level 
and stable barge pad to support the ballasted barge at the proper 
horizontal and vertical location for successful transit of modules 
across the breach. The pad would be designed to support the fully 
loaded weight of the barge and the heaviest modules.
    Pad construction would include an initial through-ice bathymetric 
survey within the breach. AGDC would conduct the through-ice survey by 
drilling or augering holes through the ice and measuring the bottom 
elevations by a survey rod tied to the local Global Positioning 
System--Real Time Kinematic (GPS-RTK) system to provide the needed 
level of accuracy of horizontal positions and vertical elevations. A 
grid of survey holes would be established over the 710 ft. (216 m) by 
160 ft. (48.8 m) dimensions (2.6 acres; 0.01 km\2\) of the breach barge 
pad to allow for determination of the bottom bathymetry such that a 
plan can be developed accordingly to prepare the barge pad surface. 
NMFS expects drilling and augering holes to produce continuous noise 
similar to other standard construction noise. We do not expect drilling 
or augering holes to result in take of marine mammals and drilling and 
auguring holes through the sea ice is not discussed further.
    Seabed preparation would consist of smoothing the seabed within the 
pad area as necessary to level the seabed across the pad at an 
elevation grade of approximately -7 ft. (-2.1 m) MLLW. Some gravel fill 
may be required at scour holes. Rock filled marine mattresses or 
gabions approximately 1 ft. (0.3 m) thick would then be placed across 
the graded pad to provide a stable and low maintenance surface at -6 
ft. (- 1.8 m) MLLW on which the barges would be grounded. These 
mattresses are gravel-filled containers constructed of high-strength 
geogrid, with the geogrid panels laced together to form mattress-shaped 
baskets.
    AGDC would conduct the seabed preparations through the ice during 
winter using excavation equipment and ice excavation methods. Equipment 
required for the grading work includes ice trenchers, excavators, 
front-end

[[Page 43386]]

loaders, man-lifts, haul trucks, survey equipment, and other ancillary 
equipment necessary to support the operation. An equipment spread 
includes a trencher for cutting ice, an excavator for removing ice, a 
second excavator, and haul units. AGDC would initiate through-ice 
grading efforts by cutting through the ice with trenchers. Excavators 
would then proceed to remove the ice to expose the seafloor bottom. 
Once a section has been exposed to the seafloor, the bottom will be 
graded to -7 ft. (-2.1 m) MLLW using the excavation equipment. AGDC 
would then install marine mattresses on the graded pad, likely 
requiring use of a crane. Grounded ice conditions are expected to occur 
at the breach on or before February 1st of each year at the latest. 
AGDC expects to conduct through-ice surveying and grading work 
immediately after, if not sooner. AGDC expects the total construction 
duration will be 45 to 60 days with construction complete by the end of 
March and demobilization from the breach area in early April. NMFS 
expects these activities to produce continuous noise similar to other 
standard construction noise. Ringed seals could be present during this 
time, particularly in subnivean lairs (Frost and Burns, 1989; Kelly et 
al., 1986; Williams et al., 2001). It is likely that few, if any, 
spotted or bearded seals would be present during that time (Bengston et 
al., 2005; Lowry et al., 1998; Simpkins et al., 2003). Additionally, we 
do not expect cetaceans to be present in the area during this time 
(Quakenbush et al., 2018, Citta et al., 2016). We do not expect these 
seabed preparation activities to result in take of marine mammals and 
do not discuss them further.
    AGDC may conduct some screeding right before the barges are placed 
in summer in an effort to achieve a surface that is near flush with 
adjacent subsurface elevations. Any screeding at the barge bridge site 
would be expected to take 14 days or less. As discussed previously, 
NMFS does not expect screeding to result in marine mammal harassment, 
therefore, screeding is not discussed further in this document.
    Barge Bridge Installation--The first two barges to offload 
materials would be used to form the temporary bridge, paralleling the 
existing weight-limited bridge, and spanning the breach. AGDC would 
move these barges into place against the mooring dolphins with tugs 
where they would be ballasted and fastened to the causeway abutments 
and each other. The two ballasted barges would be placed bow-to-bow 
when resting on the seafloor. The barge rakes would angle upward and 
touch at their adjoining point, leaving an approximately 52.5-ft (16-m) 
gap at the seafloor between the barges. The stern of each barge would 
angle sharply upward at each end of the bridge, leaving an additional 
10-ft (3.1-m) gap at the seafloor at each end.
    Ramps would be installed to accommodate smooth transit of the self-
propelled module transporters (SPMTs) over the bridge. Modules would be 
transported by SPMTs down the causeway and over the temporary bridge to 
a staging pad at the base of West Dock. From there, they would be moved 
southward over approximately 6 mi (9.7 km) of new and existing roads to 
the GTP construction site.
    AGDC expects construction of the temporary barge bridge will last 3 
days. The temporary bridge would be held in place by the mooring 
dolphins. AGDC expects the temporary bridge to be in place for 21 to 39 
days, depending on weather conditions and logistics. At the conclusion 
of each year's sealift, AGDC would de-ballast the barges and remove 
them from the breach. Upon the subsequent summer season and the next 
sealift, AGDC would position the barges back in the breach and re-
ballast them onto the barge pad for module transport operations. NMFS 
does not expect placement or removal of the barge bridges to result in 
take of marine mammals, and we do not discuss it further.
    AGDC plans to leave West Dock modifications in place after modules 
are offloaded, as their removal would result in greater disturbance to 
the surrounding environment. AGDC also plans to leave the piling and 
infrastructure forming the offshoot and ramp to the temporary barge 
bridge in place, as removing it may result in erosion or weakening of 
the existing causeway. AGDC would cut the mooring pilings below the 
sediment surface, remove them, and cover the area with surrounding 
sediment.
    Sealifts--AGDC has proposed six sealifts, consisting of two 
preliminary sealifts (NEG1 and NEG2) transporting materials (smaller 
modules, equipment, and supplies) and four primary sealifts (Sealifts 
1-4) carrying the GTP modules. AGDC identified the timing, numbers of 
vessels, and numbers of modules associated with each of these six 
sealifts in their application (See Tables 8 and 9 of AGDC's 
application).
    The barges will transport the modules from the manufacturing site 
(likely in Asia) with first call being Dutch Harbor to clear customs. 
The barges would then proceed to a designated Marine Transit Staging 
Area (MTSA), with Port Clarence being the preferred location for the 
MTSA at this time. The tug and barge will wait in a secure anchorage 
there until sea ice conditions have improved to 3/10 ice cover or 
better. The tow spread would be accompanied by a light aircraft which 
would repeatedly fly along the tow route to give a detailed report on 
sea and ice conditions. When such conditions are favorable, the tug and 
barge would proceed to the Prudhoe Bay Offshore Staging Area (PBOSA) 
located south (shoreward) of Reindeer Island and approximately 5 mi (8 
km) north of DH4 to await berthing at DH4.
    The sealift barges would be moved from the PBOSA to DH4 with the 
shallow draft assist tugs. Offloading operations at DH4 would occur 24 
hours a day during periods of favorable metocean and weather 
conditions. Current North Slope sealift practices limit operations to 
wind speed below 20 knots. The barges would be butted up against the 
dock face and then ballasted down until they rest on the prepared barge 
bearing pad. Ramps would be placed to connect the barge deck with the 
dock so that the SPMTs are able to roll under the modules, lift them, 
then roll out and transport them to the onshore module staging area.
    The barges would be demobilized from the PBOSA by ocean-going tugs 
using standard marine shipping routes. The barges would transit 
individually through the Beaufort and Chukchi seas rather than in 
groups, as occurred during their arrival into Prudhoe Bay. They would 
be demobilized from Prudhoe Bay on or about mid-September. NMFS does 
not expect take to occur associated with ordinary vessel transit, and 
therefore the use of sealifts is not discussed further.
    NMFS is carrying forward impact and vibratory pile driving and 
removal (piles indicated in Table 4) for further analysis regarding 
potential take of marine mammals. 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 regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://
www.fisheries.noaa.gov/national/

[[Page 43387]]

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). Additional information may be 
found in the Aerial Survey of Arctic Marine Mammals (ASAMM) reports, 
which are available online at https://www.fisheries.noaa.gov/alaska/marine-mammal-protection/aerial-surveys-arctic-marine-mammals.
    Table 5 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 ESA and potential biological removal (PBR), where known. 
For taxonomy, we follow Committee on Taxonomy (2019). 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' 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. Pacific and Alaska SARs (e.g., Muto et al., 2019). All 
values presented in Table 5 are the most recent available at the time 
of publication and are available in the 2018 Pacific and Alaska SARs 
(Carretta et al., 2019; Muto et al., 2019) and draft 2019 Alaska SARs 
(available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                                              Table 5--Species for Which Take is Reasonably Likely to Occur
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                      ESA/MMPA     Stock abundance (CV,
                                                                                      status;        Nmin, most recent                         Annual M/
            Common name                Scientific name             Stock          strategic (Y/N)    abundance survey)            PBR            SI \3\
                                                                                        \1\                 \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray whale....................  Eschrichtius robustus  Eastern North Pacific  -/-; N           26,960 (0.05,         801.................        139
                                                                                                    25,849, 2016).
Family Balaenidae:
    Bowhead whale.................  Balaena mysticetus...  Western Arctic.......  E/D; Y           16,820 (0.052,        161.................         53
                                                                                                    16,100, 2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Beluga whale..................  Delphinapterus leucas  Beaufort Sea.........  -/-; N           39,258 (0.229, NA,    UND.................        139
                                                                                                    1992).
                                                           Eastern Chukchi Sea..  -/-; N           20,752 (0.7, 12,194,  244.................         67
                                                                                                    2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Ringed seal...................  Phoca (pusa) hispida.  Alaska...............  T/D; Y           see SAR (see SAR,     5,100...............        863
                                                                                                    see SAR, 2013.
    Spotted seal..................  Phoca largha.........  Alaska...............  -/-; N           461,625 (see SAR,     12,697..............        329
                                                                                                    423,237, 2013).
    Bearded seal..................  Erignathus barbatus..  Beringia.............  T/D; Y           see SAR (see SAR,     See SAR.............        557
                                                                                                    see SAR, 2013.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance.
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike).

    As indicated above, all six species (with seven managed stocks) in 
Table 5 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur, and we have proposed 
authorizing take. While a harbor porpoise was sighted in the 2017 ASAMM 
survey (Clarke et al., 2018), the spatial occurrence of harbor porpoise 
is such that take is not expected to occur, and they are not discussed 
further beyond the explanation provided here. Harbor porpoise (Phocoena 
phocoena) are considered to be extremely rare in the Beaufort Sea, 
particularly in the project area (Megan Ferguson, pers. comm., November 
2019).
    In addition, the polar bear may be found in Prudhoe Bay. However, 
polar bears are managed by the U.S. Fish and Wildlife Service and are 
not considered further in this document.

Bowhead Whale

    Of the five stocks of bowhead whale, only the Western Arctic stock 
is found within U.S. waters. This stock is listed as endangered under 
the ESA and depleted under the MMPA. The stock is classified as a 
strategic stock and an Alaska Species of Special Concern (Muto et al. 
2018). From 1978 to 2011, the Western Arctic stock increased at a rate 
of 3.7 percent (95 percent Confidence Interval [CI] = 2.9-4.6 percent), 
and abundance tripled from approximately 5,000 to approximately 16,820 
whales (Givens et al. 2016).

[[Page 43388]]

    Bowhead whales belonging to the Western Arctic stock are 
distributed seasonally in ice-covered waters of the Arctic and near-
Arctic, generally between 60 degrees and 75 degrees North latitude in 
the Western Arctic Basin (Moore and Reeves 1993; Muto et al. 2018). The 
majority of the stock migrates annually from wintering areas (December 
to March) in the central and northwestern Bering Sea, north through the 
Chukchi Sea in the spring (April through May) following offshore ice 
leads around the coast of Alaska, and into the eastern Beaufort Sea 
where they spend most of the summer (June through early to mid-
October). Most animals from the stock return to the Bering Sea in the 
fall (September through December) where they overwinter (Braham et al. 
1980; Moore and Reeves 1993; Citta et al. 2015; Muto et al. 2018).
    Critical habitat has not been designated for the bowhead whale. 
NMFS was petitioned in 2000 to consider designating the nearshore areas 
from Utqia[gdot]vik east to the U.S.-Canada border as critical habitat 
for the Western Arctic stock. In 2002, NMFS determined that a critical 
habitat designation was not necessary as the population was increasing 
and approaching the pre-commercial whaling size, there were no known 
habitat issues slowing the population growth, and activities that 
occurred in the petitioned area were already being managed to minimize 
impacts to the population (67 FR 55767).
    The annual migration of the Western Arctic stock to and from the 
summer feeding grounds in the Beaufort Sea has been monitored by the 
Bureau of Ocean Energy Management (BOEM) (and predecessor agencies), 
NMFS, and/or industry since 1982 (Treacy et al. 2006; Blackwell et al. 
2007; Ireland et al. 2009; Reiser et al. 2011; Bisson et al. 2013; 
Clarke et al. 2014). Survey data indicate that the fall migration off 
northern Alaska occurs primarily over the continental shelf, generally 
12-37 mi (19-60 km) offshore, in waters 66-197 ft (11-60 m deep (Moore 
et al. 1989; Moore and Reeves 1993; Treacy 2002; Monnett and Treacy 
2005; Treacy et al. 2006). Waters less than 15 ft. (4.5 m) deep are 
considered too shallow to support these whales, and in three decades of 
aerial surveys by BOEM (ASAMM), no bowhead whale has been recorded in 
waters less than 16.4 ft (5 m) deep (Clarke and Ferguson 2010).
    Monitoring surveys have been conducted annually since 2001 at the 
Northstar offshore oil and gas facility located just offshore of West 
Dock. Over 95 percent of the bowheads observed during these fall 
surveys occurred more than 13.9 mi (22.3 km) offshore in 2001, 14.2 mi 
(22.9 km) in 2002, 8.4 mi (13.5 km) in 2003, and 10.1 mi (16.3 km) in 
2004 (Blackwell et al. 2007). West Dock extends out from the shoreline 
2.7 mi (4.3 km) and is within shallow waters less than 14.2 ft (4.3 m) 
deep. The proposed project activities would occur primarily along the 
West Dock causeway in an area developed for oil and gas with existing 
vessel traffic. While a small number of bowhead whales have been seen 
or heard offshore near Prudhoe Bay in late August (LGL and Greenridge 
1996; Greene et al. 1999; Blackwell et al. 2007; Goetz et al. 2008), 
bowheads are not likely to occur in the immediate vicinity of the 
proposed activities.
    Clarke et al. (2015) identified nine biologically important areas 
(BIAs) for bowheads in the U.S. Arctic region. The spring (April-May) 
migratory corridor BIA for bowheads is far offshore from the behavioral 
disturbance zones for the project, while the fall (September-October) 
migratory corridor BIA (western Beaufort Sea on and north of the shelf) 
for bowheads is further inshore and closer to the project site. Clarke 
et al. (2015) also identified four BIAs for bowheads that are important 
for reproduction and encompassed areas where the majority of bowhead 
whales identified as calves were observed each season; none of these 
reproductive BIAs overlap directly with the behavioral disturbance 
zones for the AK LNG project. Finally, three bowhead feeding BIAs were 
identified. Again, there is no spatial overlap of the activity with 
these BIAs. In summary, we expect that bowhead whales may occur within 
the project area during the open water season. We would not expect 
bowheads to be present during AGDC's winter/spring contingency pile 
driving period.

Gray Whale

    The Eastern North Pacific (ENP) stock of gray whales utilize U.S. 
waters from the southern coast of California north into Alaska. In 
1994, the ENP stock was delisted from the ESA due to recovery (59 FR 
31094). Punt and Wade (2012) estimated the stock was at 85 percent of 
carrying capacity and is, therefore, within range of its optimum 
sustainable population (OSP).
    The majority of the ENP stock of gray whales spend the summer and 
fall feeding in the Chukchi, Beaufort, and northwestern Bering seas 
before migrating south to the warmer water lagoons of coastal Baja 
California and Mexico. Prior to 1997, reports of gray whales in the 
Beaufort Sea were very rare. A single gray whale was killed at Cross 
Island in 1933 (Maher 1960), and small numbers were observed in the 
Canadian Beaufort Sea approximately 700 coastal mi (1,100 coastal km) 
east of Point Barrow in 1980 (Rugh and Fraker 1981). Gray whale 
sightings became more common from 1998 to 2004, although still 
infrequent (Miller et al. 1999; Treacy 2000; Williams and Coltrane 
2002), and, after 2005, the species has been regularly observed in the 
Beaufort Sea (Green and Negri 2005; Green et al. 2007; Jankowski et al. 
2008; Lyons et al. 2009). Feeding gray whales were observed near Elson 
Lagoon (immediately east of Point Barrow) in 2005 (Green and Negri 
2005) and in Smith Bay (approximately 62 mi [100 km] east of Point 
Barrow) in 2007 (Green et al. 2007). Few gray whales have been 
documented as far east as Cape Halkett (approximately 99 mi [160 km] 
east of Point Barrow) in the Beaufort Sea, and their occurrence within 
the project area is not likely.
    Clarke et al. (2015) identified biologically important areas (BIAs) 
for gray whale feeding and reproduction in the U.S. Arctic region, 
however, both are far west of the project area in the Chukchi Sea.
    In summary, we expect that gray whales could occur within the 
project area during the open water season, though occurrence is not 
likely. We would not expect gray whales to be present during AGDC's 
winter/spring contingency pile driving period.

Beluga Whale

    Of the five stocks of beluga whales occurring in Alaska waters, two 
inhabit the Beaufort Sea: The Beaufort Sea stock and the Eastern 
Chukchi Sea stock. Beluga whales from the two stocks migrate between 
the Bering and Beaufort seas and are closely associated with open leads 
and polynyas. The Beaufort Sea stock departs the Bering Sea in early 
spring, migrating through the Chukchi Sea and into the Canadian 
Beaufort Sea where they spend the summer and most of the fall, 
returning to the Bering Sea in the late fall. The Eastern Chukchi stock 
remains in the Bering Sea slightly longer, departing in the late spring 
and early summer for the Chukchi Sea and western Beaufort Sea where 
they spend the summer before returning to the Bering Sea in the fall 
(Muto et al. 2018).
    O'Corry et al. (2018) studied genetic marker sets in 1,647 beluga 
whales. The data set was from over 20 years and encompassed all of the 
whales' major coastal summering regions in the Pacific Ocean. The 
genetic marker analysis of the migrating whales revealed that while 
both the wintering and

[[Page 43389]]

summering areas of the eastern Chukchi Sea and eastern Beaufort Sea 
subpopulations may overlap, the timing of spring migration differs such 
that the whales hunted at coastal sites in Chukotka, the Bering Strait 
(i.e., Diomede), and northwest Alaska (i.e., Point Hope) in the spring 
and off of Alaska's Beaufort Sea coast in summer were predominantly 
from the eastern Beaufort Sea population. Earlier genetic 
investigations and recent telemetry studies show that the spring 
migration of eastern Beaufort whales occurs earlier and through denser 
sea ice than eastern Chukchi Sea belugas. The discovery that a few 
individual whales found at some of these spring locations had a higher 
likelihood of having eastern Chukchi Sea ancestry or being of mixed-
ancestry, indicates that the Bering Strait region is also an area where 
the stock mix in spring. Citta et al. (2016) also observed that tagged 
eastern Beaufort Sea whales migrated north in the spring through the 
Bering Strait earlier than the eastern Chukchi belugas, so they had to 
pass through the latter's primary wintering area. Therefore, the 
eastern Chukchi stock is unlikely to be present in the action area at 
any time in general, particularly during summer and fall, when most 
beluga exposures would be anticipated for this project. However, we 
conservatively assume that beluga whale takes during AGDC's project 
could occur to either stock.
    Most belugas recorded during aerial surveys conducted in the 
Alaskan Beaufort Sea in the last two decades were found over 40 mi (65 
km) from shore (Miller et al. 1999; Funk et al. 2008; Christie et al. 
2010; Clarke and Ferguson 2010; Brandon et al. 2011). ASAMM 2016 
surveys reported belugas along the continental slope with few sightings 
nearshore in the western Beaufort Sea, and Clarke et al. (2017) 
reported that distribution was similar to that documented in previous 
years with light sea ice cover.
    Surveys have recorded belugas close to shore and in the vicinity of 
the activity area. Green and Negri (2005) reported small beluga groups 
nearshore Cape Lonely (August 26) and in Smith Bay (September 4). Funk 
et al. (2008) reported a group just offshore of the barrier islands 
near Simpson Lagoon. Aerts et al. (2008) reported summer sightings of 
three groups of eight animals inside the barrier islands near Prudhoe 
Bay; and Lomac-MacNair (2014) recorded 15 beluga whales offshore of 
Prudhoe Bay between July and August. While it is possible for belugas 
to occur in the project area, nearshore sightings are unlikely.
    Whales from both the Beaufort Sea and eastern Chukchi Sea stocks 
overwinter in the Bering Sea. Belugas of the eastern Chukchi may winter 
in offshore, although relatively shallow, waters of the western Bering 
Sea (Richard et al., 2001), and the Beaufort Sea stock may winter in 
more nearshore waters of the northern Bering Sea (R. Suydam, pers. 
comm. 2012c).
    Clarke et al., (2015) identified two biologically important areas 
(BIAs) for beluga whales in the U.S. Arctic region. Both the spring 
(April-May) and fall (September-October) migratory corridor BIAs for 
belugas are far offshore from the behavioral disturbance zones for the 
project.
    In summary, we expect that beluga whales from either the Beaufort 
Sea or Chukchi Sea stock may occur within the project area during the 
open water season. We would not expect belugas to be present during 
AGDC's winter/spring contingency pile driving period.

Ringed Seal

    Ringed seals are one of the most common marine mammals in the 
Beaufort, Chukchi, and Bering Seas, with the Alaska stock estimated at 
a minimum of 249,000 animals (Allen and Angliss 2011). Ringed seals 
rely on the sea ice for key life history functions and remain 
associated with the ice most of the year. They are well adapted to 
inhabiting both shorefast and pack ice, and diminishing sea ice and 
snow resulting from climate change is the primary concern for this 
population. The ice provides a platform for pupping and nursing in late 
winter and early spring, for molting in late spring to early summer, 
and for resting during other times of the year. When sea ice is at its 
maximal extent during the winter and early spring in Alaska waters, 
ringed seal numbers are high in the northern Bering Sea, and throughout 
the Chukchi and Beaufort Seas. The species is generally not abundant 
south of Norton Sound, but animals have occurred as far south as 
Bristol Bay in years of extensive ice coverage (Muto et al. 2018).
    Seasonal movements have not been thoroughly documented; however, 
most ringed seals that overwinter in the Bering and Chukchi seas are 
thought to migrate north as the ice retreats in the spring. During the 
summer, ringed seals feed in the pack ice of the northern Chukchi and 
Beaufort seas, and in nearshore ice remnants of the Beaufort Sea. As 
the ice advances with freeze-up in the fall, many seals move west and 
south and disperse throughout the Chukchi and Bering seas while some 
remain in the Beaufort Sea (Muto et al. 2018).
    Frost et al. (2004) conducted aerial surveys over the Beaufort Sea 
coast from Utqia[gdot]vik to Kaktovik and determined that ringed seal 
density was greatest in water depths between 16 and 115 ft. (5 and 35 
m), and in relatively flat ice close to the fast ice edge. Aerial 
surveys conducted in association with construction near the Northstar 
facility found ringed seal densities ranged from 0.39 to 0.83 seals per 
km\2\ (Moulton et al. 2005).
    Historically, ringed seal occurrence in or near the activity area 
has been minimal, and large concentrations of seals are not expected 
near West Dock during project operations. However, ringed seals may 
occur in the project area during the open-water season or during AGDC's 
winter/spring contingency period.

Spotted Seal

    The Alaska stock of spotted seals are found along the continental 
shelf of the Bering, Chukchi, and Beaufort Seas. During the late fall 
through spring, when seals are hauled out on sea ice, whelping, 
nursing, breeding, and molting occurs. After the sea ice has melted, 
most spotted seals haul out on land in the summer and fall (Boveng et 
al. 2009). Pupping occurs along the Bering Sea ice front during March 
and April, followed by mating and molting in May and June (Quakenbush 
1988). During the summer, the seals follow the retreating ice north 
into the Chukchi and Beaufort seas, and haul out on lagoon and river 
delta beaches during the open water period. The migration back to the 
Bering Sea wintering grounds begins with sea ice advancement, usually 
in October (Lowry et al. 1998).
    Spotted seals were recorded during barging activities between 
Prudhoe Bay and Cape Simpson from 2005-2007 (Green and Negri 2005, 
2006; Green et al. 2007). Between 23 and 54 seals were observed 
annually, with the peak distributions found off the Colville and Piasuk 
rivers. Savarese et al. (2010) surveyed the central Beaufort Sea from 
2006 to 2008 and recorded greater numbers of animals, with 59 to 125 
spotted seals observed annually. Lomac-MacNair et al. (2014) observed 
37 spotted seals in Prudhoe Bay (and another 39 that were either 
spotted or ringed seals), including several in the immediate vicinity 
of West Dock, while monitoring July-August seismic activity.
    Sighting data indicate that spotted seals could be present in the 
project area during the summer months, however,

[[Page 43390]]

we do not expect spotted seals to occur in the project area during 
AGDC's contingency period.

Bearded Seal

    The Alaska stock of bearded seals occur seasonally in the shallow 
shelf waters of the Beaufort, Chukchi, and Bering Seas (Cameron et al. 
2010). Bearded seals are closely associated with ice and their 
migration coincides with the sea ice retreat and advancement. Some 
seals are found in the Beaufort Sea year-round; however, most prefer to 
winter in the Bering Sea and summer in areas with high ice coverage 
(70-90 percent) in the Chukchi and Beaufort seas (Simpkins et al. 2003; 
Bengston et al. 2005). The stock feeds primarily on benthic organisms 
and demersal fishes, and is therefore, closely linked to shallow waters 
that are less than 656 ft. (200 m) where they can reach the seafloor to 
forage (Muto et al. 2018).
    Aerial surveys conducted in the Beaufort Sea indicated that bearded 
seals preferred water depths between 82-246 ft (25-75 m) and areas of 
open ice cover (Cameron et al. 2010). ASAMM commonly observe bearded 
seals offshore in the Beaufort Sea; however, no sightings have been 
observed in the West Dock activity area. Based on bearded seal water 
depth and ice coverage preferences, survey observations in the Prudhoe 
Bay region, and the normal level of ongoing industrial activity in the 
project area, only very small numbers of bearded seals are expected 
near the project area.
    Critical habitat has not been designated for the bearded seal (Muto 
et al. 2018).
    In summary, bearded seals may occur in the project area during the 
open water season. Bearded seals could potentially occur in the project 
area during AGDC's winter/spring contingency period, however, we would 
expect very few, if any, bearded seals to be present during this time.

Unusual Mortality Events (UME)

    A UME is defined under the MMPA as a stranding that is unexpected; 
involves a significant die-off of any marine mammal population; and 
demands immediate response. Currently, there are ongoing UME 
investigations in Alaska involving gray whales and ice seals.
    Since January 1, 2019, elevated gray whale strandings have occurred 
along the west coast of North America from Mexico through Alaska. This 
event has been declared an Unusual Mortality Event (UME), though a 
cause has not yet been determined. More information is available at 
https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2020-gray-whale-unusual-mortality-event-along-west-coast.
    Since June 1, 2018, elevated ice seal strandings have occurred in 
the Bering and Chukchi seas in Alaska. This event has been declared an 
Unusual Mortality Event (UME), though a cause has not yet been 
determined. More information is available at https://www.fisheries.noaa.gov/national/marine-life-distress/2018-2020-ice-seal-unusual-mortality-event-alaska.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 6.

                  Table 6--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 (which 
include ringed, spotted, and bearded seals) 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. 
As noted above, six marine mammal species (three cetacean and three 
phocid pinniped species) have the reasonable potential to co-occur with 
the proposed survey activities. Please refer to Table 5. Of the 
cetacean species that may be present, two are classified as low-
frequency cetaceans (i.e., gray whale and bowhead whale) and one is 
classified as a mid-frequency cetacean (i.e., beluga whale).

[[Page 43391]]

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The Estimated Take section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take section, and the Proposed Mitigation section, to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species or 
stocks.

Description of Sound Sources

    The marine soundscape is comprised of both ambient and 
anthropogenic sounds. Ambient sound is defined as the all-encompassing 
sound in a given place and is usually a composite of sound from many 
sources both near and far. The sound level of an area is defined by the 
total acoustical energy being generated by known and unknown sources. 
These sources may include physical (e.g., waves, wind, precipitation, 
earthquakes, ice, atmospheric sound), biological (e.g., sounds produced 
by marine mammals, fish, and invertebrates), and anthropogenic sound 
(e.g., vessels, dredging, aircraft, construction). The sum of the 
various natural and anthropogenic sound sources at any given location 
and time--which comprise ``ambient'' or ``background'' sound--depends 
not only on the source levels (as determined by current weather 
conditions and levels of biological and shipping activity) but also on 
the ability of sound to propagate through the environment. In turn, 
sound propagation is dependent on the spatially and temporally varying 
properties of the water column and sea floor, and is frequency-
dependent. As a result of the dependence on a large number of varying 
factors, ambient sound levels can be expected to vary widely over both 
coarse and fine spatial and temporal scales. Sound levels at a given 
frequency and location can vary by 10-20 dB from day to day (Richardson 
et al., 1995). The result is that, depending on the source type and its 
intensity, sound from the specified activity may be a negligible 
addition to the local environment or could form a distinctive signal 
that may affect marine mammals. In-water construction activities 
associated with the project would include vibratory pile driving and 
removal and impact pile driving. The sounds produced by these 
activities fall into one of two general sound types: Impulsive and non-
impulsive. Impulsive sounds (e.g., explosions, gunshots, sonic booms, 
impact pile driving) are typically transient, brief (less than one 
second), broadband, and consist of high peak sound pressure with rapid 
rise time and rapid decay (ANSI 1986; NIOSH 1998; ANSI 2005; NMFS, 
2018). Non-impulsive sounds (e.g., aircraft, machinery operations such 
as drilling or dredging, vibratory pile driving, and active sonar 
systems) can be broadband, narrowband or tonal, brief or prolonged 
(continuous or intermittent), and typically do not have the high peak 
sound pressure with raid rise/decay time that impulsive sounds do (ANSI 
1995; NIOSH 1998; NMFS 2018). The distinction between these two sound 
types is important because they have differing potential to cause 
physical effects, particularly with regard to hearing (e.g., Ward 1997 
in Southall et al., 2007).
    Two types of pile hammers would be used on this project: Impact and 
vibratory. Impact hammers operate by repeatedly dropping a heavy piston 
onto a pile to drive the pile into the substrate. Sound generated by 
impact hammers is characterized by rapid rise times and high peak 
levels, a potentially injurious combination (Hastings and Popper, 
2005). Vibratory hammers install piles by vibrating them and allowing 
the weight of the hammer to push them into the sediment. Vibratory 
hammers produce significantly less sound than impact hammers. Peak 
sound pressure levels (SPLs) may be 180 dB or greater, but are 
generally 10 to 20 dB lower than SPLs generated during impact pile 
driving of the same-sized pile (Oestman et al., 2009). Rise time is 
slower, reducing the probability and severity of injury, and sound 
energy is distributed over a greater amount of time (Nedwell and 
Edwards 2002; Carlson et al., 2005).
    The likely or possible impacts of AGDC's proposed activity on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of the equipment and personnel; however, any impacts to marine 
mammals are expected to primarily be acoustic in nature. Acoustic 
stressors include effects of heavy equipment operation during pile 
installation and removal.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving and removal is the primary means by which 
marine mammals may be harassed from AGDC's specified activity. Animals 
exposed to natural or anthropogenic sound may experience physical and 
psychological effects, ranging in magnitude from none to severe 
(Southall et al., 2007). In general, exposure to pile driving and 
removal noise has the potential to result in auditory threshold shifts 
and behavioral reactions (e.g., avoidance, temporary cessation of 
foraging and vocalizing, changes in dive behavior). Exposure to 
anthropogenic noise can also lead to non-observable physiological 
responses such as an increase in stress hormones. Additional noise in a 
marine mammal's habitat can mask acoustic cues used by marine mammals 
to carry out daily functions such as communication and predator and 
prey detection. The effects of pile driving and removal noise on marine 
mammals are dependent on several factors, including, but not limited 
to, sound type (e.g., impulsive vs. non-impulsive), the species, age 
and sex class (e.g., adult male vs. mom with calf), duration of 
exposure, the distance between the pile and the animal, received 
levels, behavior at time of exposure, and previous history with 
exposure (Wartzok et al., 2004; Southall et al., 2007). Here we discuss 
physical auditory effects (threshold shifts) followed by behavioral 
effects and potential impacts on habitat. 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. A 
TS can be permanent or temporary. As described in NMFS (2018), there 
are numerous factors to consider when examining the consequence of TS, 
including, but not limited to, the signal temporal pattern (e.g., 
impulsive or non-impulsive), likelihood an individual would be exposed 
for a long enough duration or to a high enough level to induce a TS, 
the magnitude of the TS, time to recovery (seconds to minutes or hours 
to days), the frequency range of the exposure (i.e., spectral content), 
the hearing and vocalization frequency range of the exposed species 
relative to the signal's frequency spectrum (i.e., how an 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).
    Permanent Threshold Shift (PTS)--NMFS defines PTS as a permanent,

[[Page 43392]]

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 Ward et al., 1958, 1959; 
Ward 1960; Kryter et al., 1966; Miller 1974; Ahroon et al., 1996; 
Henderson et al., 2008). PTS levels for marine mammals are estimates; 
with the exception of a single study unintentionally inducing PTS in a 
harbor seal (Phoca vitulina) (Kastak et al., 2008), there are no 
empirical data measuring PTS in marine mammals largely due to the fact 
that, for various ethical reasons, experiments involving anthropogenic 
noise exposure at levels inducing PTS are not typically pursued or 
authorized (NMFS 2018).
    Temporary Threshold Shift (TTS)--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 Southall et al., 2007), 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., 2000, 2002). As 
described in Finneran (2015), marine mammal studies have shown the 
amount of TTS increases with cumulative sound exposure level (SELcum) 
in an accelerating fashion: At low exposures with lower SELcum, the 
amount of TTS is typically small and the growth curves have shallow 
slopes. At exposures with higher SELcum, the growth curves become 
steeper and approach linear relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in 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 time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts. We note that reduced hearing sensitivity as 
a simple function of aging has been observed in marine mammals, as well 
as humans and other taxa (Southall et al., 2007), so we can infer that 
strategies exist for coping with this condition to some degree, though 
likely not without cost.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale, harbor 
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis)) 
and five species of pinnipeds exposed to a limited number of sound 
sources (i.e., mostly tones and octave-band noise) in laboratory 
settings (Finneran 2015). TTS was not observed in trained spotted and 
ringed seals exposed to impulsive noise at levels matching previous 
predictions of TTS onset (Reichmuth et al., 2016). In general, harbor 
seals and harbor porpoises have a lower TTS onset than other measured 
pinniped or cetacean species (Finneran 2015). Additionally, the 
existing marine mammal TTS data come from a limited number of 
individuals within these species. No data are available on noise-
induced hearing loss for mysticetes. For summaries of data on TTS in 
marine mammals or for further discussion of TTS onset thresholds, 
please see Southall et al., (2007), Finneran and Jenkins (2012), 
Finneran (2015), and Table 5 in NMFS (2018). Installing piles requires 
vibratory and impact pile driving in this project. There would likely 
be pauses in activities producing the sound during each day. Given 
these pauses and that many marine mammals are likely moving through the 
ensonified area and not remaining for extended periods of time, the 
potential for TS declines.
    Behavioral Harassment--Exposure to noise from pile driving and 
removal also has the potential to behaviorally disturb marine mammals. 
Available studies show wide variation in response to underwater sound; 
therefore, it is difficult to predict specifically how any given sound 
in a particular instance might affect marine mammals perceiving the 
signal. If a marine mammal does react briefly to an underwater sound by 
changing its behavior or moving a small distance, the impacts of the 
change are unlikely to be significant to the individual, let alone the 
stock or population. However, if a sound source displaces marine 
mammals from an important feeding or breeding area for a prolonged 
period, impacts on individuals and populations could be significant 
(e.g., Lusseau and Bejder 2007; Weilgart 2007; NRC 2005).
    Disturbance may result in changing durations of surfacing and 
dives, number of blows per surfacing, or moving 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. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff 2006). Behavioral responses to sound are 
highly variable and context-specific and any reactions depend on 
numerous intrinsic and extrinsic factors (e.g., species, state of 
maturity, experience, current activity, reproductive state, auditory 
sensitivity, time of day), as well as the interplay between factors 
(e.g., Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 
2007; Weilgart 2007; Archer et al., 2010). Behavioral reactions can 
vary not only among individuals but also within an individual, 
depending on previous experience with a sound source, context, and 
numerous other factors (Ellison et al., 2012), and can vary depending 
on characteristics associated with the sound source (e.g., whether it 
is moving or stationary, number of sources, distance from the source). 
In general, pinnipeds seem more tolerant of, or at least habituate more 
quickly to, potentially disturbing underwater sound than do cetaceans, 
and generally seem to be less responsive to exposure to industrial 
sound than most cetaceans. Please see Appendices B-C of Southall et 
al., (2007) for a review of studies involving marine mammal behavioral 
responses to sound. Disruption of feeding behavior can be difficult to 
correlate with anthropogenic sound exposure, so it is usually inferred 
by observed displacement from known foraging areas, the appearance of 
secondary indicators (e.g., bubble nets or sediment plumes), or changes 
in dive behavior. As for other types of behavioral response, the 
frequency, duration, and temporal pattern of signal presentation, as 
well as differences in species sensitivity, are likely contributing 
factors to differences in response in any given circumstance (e.g., 
Croll et al., 2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko 
et al., 2007). A determination of whether foraging disruptions incur 
fitness consequences would require information on or estimates of the 
energetic requirements of the affected individuals and the relationship 
between prey availability, foraging effort and success, and the life 
history stage of the animal.

[[Page 43393]]

    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle 1950; Moberg 
2000). In many cases, an animal's first and sometimes most economical 
(in terms of energetic costs) response is behavioral avoidance of the 
potential stressor. Autonomic nervous system responses to stress 
typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness. Neuroendocrine stress responses often involve the 
hypothalamus-pituitary-adrenal system. Virtually all neuroendocrine 
functions that are affected by stress--including immune competence, 
reproduction, metabolism, and behavior--are regulated by pituitary 
hormones. Stress-induced changes in the secretion of pituitary hormones 
have been implicated in failed reproduction, altered metabolism, 
reduced immune competence, and behavioral disturbance (e.g., Moberg, 
1987; Blecha, 2000). Increases in the circulation of glucocorticoids 
are also equated with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales 
(Eubalaena glacialis). These and other studies lead to a reasonable 
expectation that some marine mammals will experience physiological 
stress responses upon exposure to acoustic stressors and that it is 
possible that some of these would be classified as ``distress.'' In 
addition, any animal experiencing TTS would likely also experience 
stress responses (NRC, 2003); however, distress is an unlikely result 
of this project based on observations of marine mammals during 
previous, similar projects in the area.
    Masking--Sound can disrupt behavior through masking, or interfering 
with, an animal's ability to detect, recognize, or discriminate between 
acoustic signals of interest (e.g., those used for intraspecific 
communication and social interactions, prey detection, predator 
avoidance, navigation) (Richardson et al., 1995). Masking occurs when 
the receipt of a sound is interfered with by another coincident sound 
at similar frequencies and at similar or higher intensity, and may 
occur whether the sound is natural (e.g., snapping shrimp, wind, waves, 
precipitation) or anthropogenic (e.g., pile driving, shipping, sonar, 
seismic exploration) in origin. The ability of a noise source to mask 
biologically important sounds depends on the characteristics of both 
the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions. Masking of natural sounds can result when human activities 
produce high levels of background sound at frequencies important to 
marine mammals. Conversely, if the background level of underwater sound 
is high (e.g. on a day with strong wind and high waves), an 
anthropogenic sound source would not be detectable as far away as would 
be possible under quieter conditions and would itself be masked.
    Airborne Acoustic Effects--We do not expect harassment as a result 
of airborne sound, as there are no haul out sites near West Dock during 
the open water season. If AGDC must work during their contingency 
period, they will begin pile driving prior to March 1 (see Proposed 
Mitigation), so we would not expect ringed seals to build their lairs 
close enough to the project site to be taken by in-air sound during the 
contingency period. Therefore, we do not believe that authorization of 
incidental take resulting from airborne sound is warranted, and 
airborne sound is not discussed further here.

Marine Mammal Habitat Effects

    AGDC's construction activities could have localized, temporary 
impacts on marine mammal habitat by increasing in-water sound pressure 
levels, disturbing benthic habitat, and increased turbidity. 
Construction activities are of short duration and would likely have 
temporary impacts on marine mammal habitat through increases in 
underwater sound. Increased noise levels may affect acoustic habitat 
(see masking discussion above) and adversely affect marine mammal prey 
in the vicinity of the project area (see discussion below). During 
vibratory pile driving, elevated levels of underwater noise would 
ensonify the area where both fish and mammals may occur and could 
affect foraging success. Additionally, marine mammals may avoid the 
area during construction; any displacement due to noise is expected to 
be temporary and is not expected to result in long-term effects to the 
individuals or populations.
    Additionally, winter construction activities, including through-ice 
surveying and through-ice grading could potentially disturb ice 
habitat, as ice will be cut and removed to facilitate grading the 
seafloor. Work is expected to begin immediately after the ice becomes 
grounded, which typically occurs in the work area on or before February 
1. These activities could affect available ringed seal habitat, 
however, ringed seal density is low in areas with water depths less 
than 10 feet (3 meters; Moulton et al. 2005), and the grounded ice 
conditions suitable for construction activities are not preferred 
habitat for ringed seals. Additionally, winter construction activities 
would begin prior to March 1, further reducing the potential for 
disturbance to ringed seal birth lairs.
In-Water Construction Effects on Potential Foraging Habitat
    Potential prey (i.e., fish) may avoid the immediate area due to the 
temporary loss of this foraging habitat during pile driving activities. 
The duration of fish avoidance of this area after pile driving stops is 
unknown, but we anticipate a rapid return to normal recruitment, 
distribution and behavior. Any behavioral avoidance by fish of the 
disturbed area would still leave large areas of fish and marine mammal 
foraging habitat in the nearby vicinity.

[[Page 43394]]

    Additionally, a small amount of seafloor habitat will be disturbed 
as a result of pile driving, gravel deposition, screeding, and other 
seabed preparation. Benthic infauna abundance and diversity are very 
low in this area, likely due to the shallow water depth (<16 feet [5 
meter]), run-off from adjacent rivers, and ice related stress (Carey et 
al. 1984). Freezing and thawing sea ice and river runoff during the 
summer melting season significantly affect the coastal water mass 
characteristics and decrease the salinity. River outflow and coastal 
erosion also transport significant amounts of suspended sediments (BPXA 
2009). Sea ice pressure ridges scour and gouge the seafloor and move 
sediments, creating natural, seasonal disruptions of the seafloor. 
These factors result in a less than favorable habitat for benthic 
organisms in the activity area. Bottom disturbance is a natural and 
frequent occurrence in this nearshore region resulting in benthic 
communities with patchy distributions (Carey et al. 1984). Given the 
low nearshore densities of benthic prey items, we do not expect 
screeding, pile driving, or related construction activities to have 
significant impacts on marine mammal foraging habitat. Additionally, 
installation of the new DH4 and barge bridge abutments will cover the 
associated seafloor; however, the total seafloor area affected from 
installing the structures is a very small area compared to the vast 
foraging area available to marine mammals in the Beaufort Sea, 
particularly given the limited prey expected to be in the West Dock 
area.
    In addition to ensonification and seafloor disturbance, a temporary 
and localized increase in turbidity near the seafloor would occur in 
the immediate area surrounding the area where piles are installed and 
removed, and where screeding and seabed preparation will take place. 
The screeding process redistributes seabed materials to create a flat 
even seafloor surface without the need for excavation or disposal of 
materials. Screeding would occur each summer immediately prior to the 
arrival of the first cargo barge, and would likely increase turbidity 
in the immediate area around West Dock. Turbidity and sedimentation 
rates are naturally high in this region due to ice scouring and gouging 
of the seafloor and significant amounts of suspended sediments from 
river outflow and coastal erosion. Therefore, the additional turbidity 
resulting from screeding activities is not anticipated to have a 
significant impact. The sediments on the sea floor will also be 
disturbed during pile driving; however, like during screeding, sediment 
suspension will be brief and localized and is unlikely to measurably 
affect marine mammals or their prey in the area. In general, turbidity 
associated with pile installation is localized to about a 25-ft radius 
around the pile (Everitt et al., 1980). Cetaceans are not expected to 
be close enough to the project pile driving areas to experience effects 
of turbidity, and any pinnipeds are able to easily avoid localized 
areas of turbidity. Therefore, the impact from increased turbidity 
levels is expected to be discountable to marine mammals. Furthermore, 
pile driving and removal at the project site would not obstruct 
movements or migration of marine mammals.
    Impacts to potential foraging habitat are expected to be temporary 
and minimal based on the short duration of activities.
In-Water Construction Effects on Potential Prey
    Numerous fish and invertebrate species occur in Prudhoe Bay and the 
Beaufort Sea, and could be affected by the construction activities that 
would produce continuous (i.e., vibratory pile driving) and impulsive 
(i.e., impact pile driving) sounds. Fish react to sounds that are 
especially strong and/or intermittent low-frequency sounds. Short 
duration, sharp sounds can cause overt or subtle changes in fish 
behavior and local distribution. Hastings and Popper (2005) identified 
several studies that suggest fish may relocate to avoid certain areas 
of sound energy. Additional studies have documented effects of pile 
driving on fish, although several are based on studies in support of 
large, multiyear bridge construction projects (e.g., Scholik and Yan 
2001, 2002; Popper and Hastings 2009). Sound pulses at received levels 
of 160 dB may cause subtle changes in fish behavior. SPLs of 180 dB may 
cause noticeable changes in behavior (Pearson et al., 1992; Skalski et 
al., 1992). SPLs of sufficient strength have been known to cause injury 
to fish and fish mortality.
    The most likely impact to fish from pile driving activities at the 
project site would be temporary behavioral avoidance of the area. The 
duration of fish avoidance of this area after pile driving stops is 
unknown, but as noted above, a rapid return to normal recruitment, 
distribution and behavior is anticipated.
    Popper and Hastings (2009) reviewed information on the effects of 
pile driving and concluded that there are no substantive data on 
whether the high sound levels from pile driving or any man-made sound 
would have physiological effects on invertebrates. Any such effects 
would presumably be limited to the area very near (3-16 ft. [1-5 m]) 
the sound source and would result in no population effects due to the 
relatively small area affected at any one time and the reproductive 
strategy of most zooplankton species (short generation, high fecundity, 
and very high natural mortality). No adverse impact on zooplankton 
populations would be expected to occur from these activities, due in 
part to large reproductive capacities and naturally high levels of 
predation and mortality of these populations. Any mortalities or 
impacts that might occur would be expected to be negligible compared to 
the naturally occurring high reproductive and mortality rates.
    As noted above, due to the limited presence of benthic 
invertebrates in the West Dock area, we do not expect screeding and 
seafloor preparation activities to result in a significant loss of 
benthic prey availability, particularly in comparison to the vast 
foraging area available to marine mammals in the Beaufort Sea.
    In summary, given the short daily duration of sound associated with 
individual pile driving events and the relatively small areas being 
affected, pile driving activities associated with the proposed action 
are not likely to have a permanent, adverse effect on any fish or 
invertebrate habitat, or populations of fish or invertebrate species. 
Thus, we conclude that impacts of the specified activity are not likely 
to have more than short-term adverse effects on any prey habitat or 
populations of prey species. Further, any impacts to marine mammal 
habitat are not expected to result in significant or long-term 
consequences for individual marine mammals, or to contribute to adverse 
impacts on their populations.

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 
determination.
    Harassment is the only type of take 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

[[Page 43395]]

not limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of the acoustic source (i.e., vibratory and impact pile driving) has 
the potential to result in disruption of behavioral patterns for 
individual marine mammals. There is also some potential for auditory 
injury (Level A harassment) to result, primarily for phocids, due to 
their lack of visibility and the size of the Level A harassment zones. 
Auditory injury is unlikely to occur to cetaceans. The proposed 
mitigation and monitoring measures are expected to minimize the 
severity of the taking to the extent practicable.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed or incur some 
degree of permanent hearing impairment; (2) the area or volume of water 
that will be ensonified above these levels in a day; (3) the density or 
occurrence of marine mammals within these ensonified areas; and, (4) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of takes, additional information that can qualitatively 
inform take estimates is also sometimes available (e.g., previous 
monitoring results or average group size). Below, we describe the 
factors considered here in more detail and present the proposed take 
estimate.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably expected to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2012). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g., 
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms) 
for non-explosive impulsive (e.g., seismic airguns) or intermittent 
(e.g., scientific sonar) sources.
    AGDC's construction activity includes the use of continuous 
(vibratory pile driving) and impulsive (impact pile driving) sources, 
and therefore the 120 and 160 dB re 1 [mu]Pa (rms) are 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). AGDC's construction activity includes the 
use of impulsive (impact pile driving) and non-impulsive (vibratory 
pile driving) 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 7--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.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., vibratory pile driving and 
removal). The maximum (underwater) area ensonified above the

[[Page 43396]]

thresholds for behavioral harassment referenced above is 67.7km\2\ 
(26.1mi\2\), and the calculated distance to the farthest behavioral 
isopleth is approximately 4.6km (2.9mi).
    The project includes vibratory pile installation and removal and 
impact pile installation. Source levels for these activities are based 
on reviews of measurements of the same or similar types and dimensions 
of piles available in the literature. Source levels for each pile size 
and activity are presented in Table 8. Source levels for vibratory 
installation and removal of piles of the same diameter are assumed to 
be the same.

                                  Table 8--Sound Source Levels for Pile Driving
----------------------------------------------------------------------------------------------------------------
                                                              Source level (at 10m)
      Pile size and type          Hammer type   ------------------------------------------------    Literature
                                                     SPLrms           Peak             SEL            source
----------------------------------------------------------------------------------------------------------------
11.5-inch H-Pile.............  Impact..........             183             200             170  Caltrans 2015
                                                                                                  (12-in H-
                                                                                                  Pile).
14-inch H-Pile...............  Impact..........             187             208             177  Caltrans 2015
                                                                                                  (14-in H-
                                                                                                  Pile).
                               Vibratory.......             150             160             150  Caltrans 2015
                                                                                                  (12-in H-
                                                                                                  Pile).
48-inch Pipe Pile............  Impact..........             195             210             185  Caltrans 2015
                                                                                                  (60-in CISS
                                                                                                  Pile).
Sheet Piles (19.69-inch and    Vibratory.......             160             175             160  Caltrans 2015
 25-inch).                                                                                        (AZ Sheet
                                                                                                  Pile).
----------------------------------------------------------------------------------------------------------------

    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B * Log10 (R1/R2),

where

TL = transmission loss in dB
B = transmission loss coefficient
R1 = the distance of the modeled SPL from the driven pile, and
R2 = the distance from the driven pile of the initial measurement

    Absent site-specific acoustical monitoring with differing measured 
transmission loss, a practical spreading value of 15 is used as the 
transmission loss coefficient in the above formula. Project and site-
specific transmission loss data for the Prudhoe Bay portion of AGDC's 
AK LNG project are not available; therefore, the default coefficient of 
15 is used to determine the distances to the Level A and Level B 
harassment thresholds.
    When the NMFS Technical Guidance (2016) was published, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of Level A harassment take. However, these tools offer the 
best way to predict appropriate isopleths when more sophisticated 3D 
modeling methods are not available, and NMFS continues to develop ways 
to quantitatively refine these tools, and will qualitatively address 
the output where appropriate. For stationary sources such as pile 
driving, NMFS User Spreadsheet predicts the distance at which, if a 
marine mammal remained at that distance the whole duration of the 
activity, it would incur PTS. Inputs used in the User Spreadsheet, and 
the resulting isopleths are reported below.

                              Table 9--User Spreadsheet Input Parameters Used for Calculating Level A Harassment Isopleths
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                   19.69-inch sheet      25-inch sheet
                                   11.5-inch H-pile     14-inch H-pile      14-inch H-pile     48-inch pipe pile         piles               piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............  E.1) Impact pile    E.1) Impact pile    A.1) Vibratory      E.1) Impact pile    A.1) Vibratory      A.1) Vibratory
                                   driving.            driving.            pile driving.       driving.            pile driving.       pile driving
Weighting Factor Adjustment       2.................  2.................  2.5...............  2.................  2.5...............  2.5
 (kHz).
Source Level....................  170 dB SEL........  177 dB SEL........  150 SPLrms........  185 dB SEL........  160 SPLrms........  160 SPLrms
Number of piles within 24-h       26.09 \b\.........  4.................  8.................  1.25..............  15.24 \b\.........  12
 period \a\.
Duration to drive a single pile   ..................  ..................  15................  ..................  18.9..............  24
 (minutes).
Number of strikes per pile......  1,000.............  1,000.............  ..................  1,000.............  ..................  ..................
Propagation (xLogR).............  15................  15................  15................  15................  15................  15
Distance from source level        10................  10................  10................  10................  10................  10
 measurement (meters).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ These estimates include contingencies for weather, equipment, work flow, and other factors that affect the number of piles per day, and are assumed
  to be a maximum anticipated per day. Given that AGDC plans to pile drive up to 24 hours per day, it is appropriate to assume that the number of piles
  installed within the 24-hour period may not be a whole number.
\b\ These averages assume that AGDC will drive 11.5-inch H-piles and sheet piles at a rate of 25 feet per day.


[[Page 43397]]


                   Table 10--Calculated Distances to Level A and Level B Harassment Isopleths
----------------------------------------------------------------------------------------------------------------
                                                            Level A harassment zone (m)               Level B
           Activity                Hammer type   ------------------------------------------------   harassment
                                                   LF cetaceans    MF cetaceans       Phocids        zone (m)
----------------------------------------------------------------------------------------------------------------
11.5-inch H-Pile..............  Impact..........           1,194              43             639             341
14-inch H-Pile................  Impact..........           1,002              36             536             631
                                Vibratory.......               2              <1               1           1,000
48-inch Pipe Pile.............  Impact..........           1,575              56             843           2,154
19.69-inch Sheet Piles........  Vibratory.......              17               2              10           4,642
25-inch Sheet Piles...........  Vibratory.......              17               2              10           4,642
----------------------------------------------------------------------------------------------------------------

    Level A harassment zones are typically smaller than Level B 
harassment zones. However, in rare cases such as the impact pile 
driving of the 11.5-inch and 14-inch H-piles in AGDC's project, the 
calculated Level A harassment isopleth is greater than the calculated 
Level B harassment isopleth. Calculation of Level A harassment 
isopleths include a duration component, which in the case of impact 
pile driving, is estimated through the total number of daily strikes 
and the associated pulse duration. For a stationary sound source such 
as impact pile driving, we assume here that an animal is exposed to all 
of the strikes expected within a 24-hour period. Calculation of a Level 
B harassment zone does not include a duration component. Depending on 
the duration included in the calculation, the calculated Level A 
harassment isopleths can be larger than the calculated Level B 
harassment isopleth for the same activity.

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.
    Each fall and summer, NMFS and BOEM conduct an aerial survey in the 
Arctic, the ASAMM surveys (Clarke et al., 2012, 2013a, 2014, 2015, 
2017a, 2017b, 2018, 2019). The goal of these surveys is to document the 
distribution and relative abundance of bowhead, gray, right, fin and 
beluga whales and other marine mammals in areas of potential oil and 
natural gas exploration, development, and production activities in the 
Alaskan Beaufort and northeastern Chukchi Seas. Traditionally, only 
fall surveys were conducted but, in 2011, the first dedicated summer 
survey effort began in the ASAMM Beaufort Sea study area. AGDC used 
these ASAMM surveys as the data source to estimate seasonal densities 
of cetaceans (bowhead, gray and beluga whales) in the project area. The 
ASAMM surveys are conducted within blocks that overlay the Beaufort and 
Chukchi Seas oil and gas lease sale areas offshore of Alaska (Figure 16 
in AGDC's application), and provide sighting data for bowhead, gray, 
and beluga whales during summer and fall months. During the summer and 
fall, NMFS observed for marine mammals on effort for 13,484 km and 
12,846 km, respectively, from 2011 through 2018. Data from those 
surveys are used for this analysis. We note that the proposed Prudhoe 
Bay portion of the AK LNG project is in ASAMM survey block 1; the 
inshore boundary of this block terminates at the McClure Island group. 
It was not until 2016 that on-effort surveys began inside the McClure 
Island group (including Prudhoe Bay) since bowhead whales, the focus of 
the surveys, are not likely to enter this area, given its shallow 
depth. However, no bowheads and only one beluga whale have been 
observed in block 1a (including Prudhoe Bay). Therefore, the density 
estimates provided here are an overestimate because they rely on 
offshore surveys where marine mammals are more likely to be present.
Bowhead Whale
    AGDC calculated density estimates for bowhead whale by dividing the 
average number of whales observed per km of transect effort in ASAMM 
Block 1 (whales/km in Table 11) by two times the effective strip width 
(ESW) to encompass both sides of the transect line (whales per km/(2 x 
ESW). The ESW for bowhead whales from the Aero Commander aircraft is 
1.15 km (0.71 mi) (Ferguson and Clarke 2013). Therefore, the summer 
density estimate is 0.005 bowhead whales/km\2\, and the fall density 
estimate is 0.017 bowhead whales/km\2\. The resulting densities are 
expected to be overestimates for the AK LNG analysis because the data 
is based on sighting effort outside of the barrier islands, and bowhead 
whales rarely occur within the barrier islands. However, AGDC 
conservatively used the higher fall density to estimate potential Level 
B harassment takes.
    As noted in the Description of Marine Mammals in the Area of 
Specified Activities section, we do not expect bowhead whales to be 
present during AGDC's winter/spring contingency pile driving period.

                                  Table 11--Bowhead Whale Sighting Data From 2011 Through 2018 and Resulting Densities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Summer                                               Fall
                                                --------------------------------------------------------------------------------------------------------
                      Year                        Number of                                            Number of
                                                    whales      Transect    Whales/km   Whales/km\2\     whales      Transect    Whales/km     Whales/
                                                   sighted    effort (km)                    \a\        sighted    effort (km)                km\2\ \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011...........................................            1          346        0.003        0.001            24        1,130        0.021        0.009
2012...........................................            5        1,493        0.003        0.001            17        1,696        0.010        0.004
2013...........................................           21        1,582        0.013        0.006            21        1,121        0.019        0.008
2014...........................................           17        1,393        0.012        0.005            79        1,538        0.051        0.022
2015...........................................           15        1,262        0.012        0.005            17        1,663        0.010        0.004
2016...........................................           97        1,914        0.051        0.022            23        2,360        0.010        0.004
2017...........................................            8        3,003        0.003        0.001           255        1,803        0.141        0.061
2018...........................................            2        2,491        0.001       0.0004            69        1,535        0.045        0.020
                                                --------------------------------------------------------------------------------------------------------

[[Page 43398]]

 
    Total......................................          166       13,484    \b\ 0.012    \b\ 0.005           505       12,846    \b\ 0.039    \b\ 0.017
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Calculated using an effective strip width of 1.15 km.
\b\ Value represents average, not total, across all years.

Gray Whale
    Gray whale sightings in the Beaufort Sea have increased in recent 
years, however, encounters are still infrequent. AGDC calculated 
density estimates for gray whale by dividing the average number of 
whales observed per km of transect effort (whales/km in Table 12) by 
two times the ESW to encompass both sides of the transect line (whales 
per km/(2 x ESW). The ESW for gray whales from the Aero Commander 
aircraft is 1.20 km (0.75 mi) (Ferguson and Clarke 2013). Therefore, 
the summer and fall density estimates are both 0.00003 gray whales/
km\2\. The resulting densities are expected to be overestimates for the 
AK LNG analysis because the data is based on sighting effort outside of 
the barrier islands, and gray whales rarely occur within the barrier 
islands as evidenced by Block 1A ASAMM surveys.
    As noted in the Description of Marine Mammals in the Area of 
Specified Activities section, we do not expect gray whales to be 
present during AGDC's winter/spring contingency pile driving period.

                                    Table 12--Gray Whale Sighting Data From 2011 Through 2018 and Resulting Densities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Summer                                               Fall
                                                --------------------------------------------------------------------------------------------------------
                      Year                        Number of                                            Number of
                                                    whales      Transect    Whales/km   Whales/km\2\     whales      Transect    Whales/km     Whales/
                                                   sighted    effort (km)                    \a\        sighted    effort (km)                km\2\ \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011...........................................            0          346            0            0             0        1,130            0            0
2012...........................................            0        1,493            0            0             0        1,696            0            0
2013...........................................            0        1,582            0            0             0        1,121            0            0
2014...........................................            0        1,393            0            0             1        1,538       0.0007       0.0003
2015...........................................            0        1,262            0            0             0        1,663            0            0
2016...........................................            1        1,914        0.003        0.001             0        2,360            0            0
2017...........................................            0        3,003            0            0             0        1,803            0            0
2018...........................................            0        2,491            0            0             0        1,535            0            0
                                                --------------------------------------------------------------------------------------------------------
    Total......................................            1       13,484  \b\ 0.00007  \b\ 0.00003             1       12,846  \b\ 0.00008  \b\ 0.00003
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Calculated using an effective strip width of 1.20 km.
\b\ Value represents average, not total, across all years.

Beluga Whale
    AGDC calculated beluga densities for survey block 1 (the area 
offshore from the McClure Island group) using ASAMM data collected from 
2014-2018. Beluga sighting data was included in surveys from 2011 to 
2013, however, this data is only summarized by depth zone, rather than 
by survey block. Therefore, the National Marine Mammal Laboratory 
(Megan Ferguson, pers. comm., November 18, 2019), advised NMFS and AGDC 
to calculate beluga whale density using the 2014-2018 ASAMM data, as it 
is more recent and incorporates more years. Density estimates for 
beluga whale were calculated by dividing the average number of whales 
observed per km of transect effort (whales/km in Table 13) by two times 
the effective strip width to encompass both sides of the transect line 
(whales per km/(2 x ESW). The ESW for beluga whales from the Aero 
Commander aircraft is 0.614 km (0.38 mi) (Ferguson and Clarke 2013). 
The resulting summer density estimate is 0.005 beluga whales/km\2\, and 
the fall density estimate is 0.001 beluga whales/km\2\. AGDC 
conservatively used the higher summer density to estimate potential 
Level B harassment takes.
    The resulting densities are expected to be overestimates for the AK 
LNG analysis because the data is based on sighting effort outside of 
the barrier islands, and beluga whales rarely occur within the barrier 
islands, as evidenced by Block 1a ASAMM survey data. Block 1a 
encompasses the area between the shoreline and the barrier islands, 
including Prudhoe Bay. One beluga whale was observed in survey block 1a 
in 2018. However, this sighting was a ``sighting on search'' and 
therefore was not included in the density calculation.
    As noted in the Description of Marine Mammals in the Area of 
Specified Activities section, we do not expect beluga whales to be 
present during AGDC's winter/spring contingency pile driving period.

[[Page 43399]]



                                   Table 13--Beluga Whale Sighting Data From 2011 Through 2018 and Resulting Densities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Summer                                               Fall
                                                --------------------------------------------------------------------------------------------------------
                      Year                        Number of                                            Number of
                                                    whales      Transect    Whales/km   Whales/km\2\     whales      Transect    Whales/km     Whales/
                                                   sighted    effort (km)                    \a\        sighted    effort (km)                km\2\ \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
2014...........................................           13        1,393        0.009        0.008             9        1,538        0.006        0.005
2015...........................................           37        1,262        0.029        0.024             3        1,663        0.002        0.001
2016...........................................            0        1,914            0            0             1        2,360       0.0004       0.0003
2017...........................................            4        3,003        0.001        0.001             0        1,803            0            0
2018...........................................            6        2,491        0.002        0.002             0        1,535            0            0
                                                --------------------------------------------------------------------------------------------------------
    Total......................................           60       10,063    \b\ 0.006    \b\ 0.005            13        8,899    \b\ 0.001    \b\ 0.001
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Calculated using an effective strip width of 0.614 km.
\b\ Value represents average, not total, across all years.

Ringed Seal
    Ringed seals are the most abundant species in the project area. 
They haul out on the ice to molt between late May and early June, and 
spring aerial surveys provide the most comprehensive density estimates 
available. Industry monitoring programs for the construction of the 
Northstar production facility conducted spring aerial surveys in the 
area surrounding West Dock from 1997 to 2002 (Frost et al., 2002; 
Moulten et al., 2002b; Moulton et al., 2005; Richardson and Williams, 
2003). Spring surveys are expected to provide the best ringed seal 
density information, as the greatest percentage of seals have abandoned 
their lairs and are hauled out on the ice (Kelly et al., 2010). 
Densities were consistently very low in areas where the water depth was 
less than 10 ft. (3 m), and only sightings observed in water depths 
greater than 10 ft. (3 m) have been included in the density 
calculations (Moulton et al., 2002a, Moulton et al., 2002b, Richardson 
and Williams, 2003). The average observed spring ringed seal density 
from this monitoring effort was 0.548 seals/km\2\ (Table 14). These 
densities are not corrected for unobserved animals, and therefore may 
result in an underestimated density.

  Table 14--Ringed Seal Densities Estimated From Spring Aerial Surveys
                       Conducted From 1997 to 2002
------------------------------------------------------------------------
                                                          Density (Seals/
                          Year                                km\2\)
------------------------------------------------------------------------
1997....................................................            0.43
1998....................................................            0.39
1999....................................................            0.63
2000....................................................            0.47
2001....................................................            0.54
2002....................................................            0.83
                                                         ---------------
  Average...............................................           0.548
------------------------------------------------------------------------

    In order to generate a summer density, as AGDC expects that the 
majority of their work will occur during the summer, we first begin 
with the spring density. Summer densities in the project area are 
expected to significantly decrease as ringed seals range considerable 
distances during the open water season. Summer density was estimated to 
be 50 percent of the spring density (0.548 seals/km\2\), resulting in a 
summer density estimate of 0.274 ringed seals/km\2\. Like summer 
density estimates, fall density data are limited. Ringed seals remain 
in the water through the fall and into the winter. Given the lack of 
data, fall density is assumed the same as the summer density of 0.274 
ringed seals/km\2\.
    During the winter months, ringed seals create subnivean lairs and 
maintain breathing holes in the landfast ice. Tagging data suggest that 
ringed seals utilize multiple lairs and Kelly et al. (1986) determined 
that, on average, one seal used 2.85 lairs, although the authors 
suggested that this is likely an underestimate. Density estimates for 
the number of ringed seal ice structures have been calculated (Frost 
and Burns 1989; Kelly et al. 1986; Williams et al. 2001), and the 
average density of ice structures from these reports is 1.58/km\2\.
    To estimate ringed seal density in the winter, the average ice 
structure density (1.58/km\2\) was divided by the average number of 
structures used by the seals (2.85 structures). The estimated density 
is 0.509 ringed seals/km\2\ in the winter; however, this is likely an 
overestimate as the average number of ice structures utilized is 
thought to be an underestimate (Kelly et al., 1986).
    While more recent ASAMM surveys have been conducted in the project 
area (2016-2018), these surveys did not identify observed pinnipeds to 
species (Clarke et al., 2019).

                 Table 15--Ringed Seal Ice Structure Density in the Vicinity of the Project Area
----------------------------------------------------------------------------------------------------------------
                                                   Ice structure
                     Year                       density (structures                     Source
                                                    per km\2\)
----------------------------------------------------------------------------------------------------------------
1982.........................................                   3.6  Frost and Burns 1989.
1983.........................................                  0.81  Kelly et al., 1986.
1999.........................................                  0.71  Williams et al., 2001.
2000.........................................                   1.2  Williams et al., 2001.
                                              ------------------------------------------------------------------
    Average Density..........................                  1.58
----------------------------------------------------------------------------------------------------------------

    Given that AGDC will only pile drive during the winter if they are 
unable to complete the work during the summer and fall open water 
season, AGDC estimated ringed seal takes using summer densities, rather 
than winter. NMFS concurs with this approach.
Spotted Seal
    The spotted seal occurs in the Beaufort Sea in small numbers during 
the summer open water period. At the

[[Page 43400]]

onset of freeze-up in the fall, spotted seals return to the Chukchi and 
then Bering Sea to spend the winter and spring. As such, we do not 
expect spotted seals to occur in the project area during AGDC's winter/
spring contingency period.
    Only a few of the studies referenced in calculating the ringed seal 
densities also include data for spotted seals. Given the limited 
spotted seal data, NMFS expects that relying on this data may result in 
an underestimate, and that it is more conservative to calculate the 
spotted seal density as a proportion of the ringed seal density. 
Therefore, summer spotted seal density was estimated as a proportion of 
the ringed seal summer density based on the percentage of pinniped 
sightings observed during monitoring projects in the region (Harris et 
al., 2001; Aerts et al., 2008; Hauser et al., 2008; HDR 2012). Spotted 
seals comprised 20 percent of the pinniped sightings during these 
monitoring efforts. Therefore, summer spotted seal density was 
calculated as 20 percent of the ringed seal density of 0.274 seals/
km\2\. This results in an estimated spotted seal summer density of 
0.055 seals/km\2\.
Bearded Seal
    The majority of bearded seals spend the winter and spring in the 
Chukchi and Bering seas; however, some remain in the Beaufort Sea year-
round. A reliable population estimate for the bearded seal stock is not 
available, and occurrence in the Beaufort Sea is less known than that 
in the Bering Sea. Spring aerial surveys conducted as part of industry 
monitoring for the Northstar production facility provide limited 
sighting numbers from 1999-2002 (Moulton et al., 2000, Moulton et al., 
2001, Moulton et al., 2002a, Moulton et al., 2003). During the 4 years 
of survey, an average of 11.75 bearded seals were observed during 
3,997.5 km\2\ of effort. Using this data, winter and spring density are 
estimated to be 0.003 bearded seals/km\2\.
    Bearded seals occur in the Beaufort Sea more frequently during the 
open water season, rather than other parts of the year. They prefer 
waters farther offshore. Only a few of the studies referenced in 
calculating the ringed seal densities also include data for bearded 
seals. Given the limited bearded seal data, NMFS expects that relying 
on this data may result in an underestimate, and that it is more 
conservative to calculate the bearded seal density as a proportion of 
the ringed seal density. Therefore, summer density was estimated as a 
proportion of the ringed seal summer density based on the percentage of 
pinniped sightings observed during monitoring projects in the region 
(Harris et al., 2001; Aerts et al., 2008; Hauser et al., 2008; HDR 
2012). Bearded seals comprised 17 percent of the pinniped sightings 
during these monitoring efforts. Therefore, summer bearded seal density 
was calculated as 17 percent of the ringed seal density of 0.274 seals/
km\2\. This results in an estimated bearded seal summer density of 
0.047 seals/km\2\. The same estimate is assumed for bearded seal fall 
density.
    As noted in the Description of Marine Mammals in the Area of 
Specified Activities section and in Table 16, bearded seals could 
potentially occur in the project area during AGDC's winter/spring 
contingency period. However, we would expect very few, if any, bearded 
seals to be present during this time. In consideration of this species 
presence information, and AGDC's plan to conduct most construction 
during the open-water season, NMFS used the summer density in the take 
calculation described below.

                      Table 16--Marine Mammal Densities in the Geographic Region by Season
----------------------------------------------------------------------------------------------------------------
                                                   Winter (Nov-    Spring (Apr-    Summer (Jul-
                     Species                           Mar)          Jun) \a\          Aug)         Fall (Sept-
-------------------------------------------------------------------------------------------------------Oct)-----
Bowhead Whale...................................               0               0           0.005           0.017
Gray Whale......................................               0               0         0.00003         0.00003
Beluga Whale....................................               0               0           0.005           0.001
Ringed Seal.....................................           0.507           0.548           0.274           0.274
Spotted Seal....................................               0               0           0.055               0
Bearded Seal....................................           0.003           0.003           0.047           0.047
----------------------------------------------------------------------------------------------------------------
\a\ AGDC's pile driving contingency period extends from late February to April 2023, however, very little if any
  pile driving is likely to occur in April.

Take Calculation and Estimation

    In this section, we describe how the information provided above is 
brought together to produce a quantitative take estimate.
    To calculate estimated Level A and Level B harassment takes, AGDC 
multiplied the area (km\2\) estimated to be ensonified above the Level 
A or Level B harassment thresholds for each species, respectively, for 
pile driving (and removal) of each pile size and hammer type by the 
duration (days) of that activity in that season by the seasonal density 
for each species (number of animals/km\2\).
    AGDC expects that construction will likely be completed during the 
open-water construction season. AGDC calculated that the construction 
will require approximately 164 days of in-water work; however, this 
estimate does not take into account that different pile types would be 
installed on the same day, therefore reducing the total number of pile 
driving days. Therefore, NMFS expects that the take calculation using 
the method described above overestimates take. Taking into 
consideration the number of calendar days, no work occurring on days 
during the whaling season, construction occurring 6 days per week, 
there are 123 days in the months of July through October on which the 
work is expected to occur (75 percent of the 164 days estimated by 
AGDC). As such, NMFS is proposing to authorize 75 percent of the take 
estimate calculated by AGDC for each species (except for Level A 
harassment take of bowhead whales and beluga whales, and Level B 
harassment of gray whales as noted below).
    NMFS recognizes that AGDC may work outside of this period in their 
February to April contingency period; however, we expect that if AGDC 
works during the contingency period, it would be because of 
construction delays (and therefore, days on which they did not work) 
during their planned open water work season. Additionally, we recognize 
that ringed seals may be present in ice lairs during the contingency 
period. However, AGDC must initiate pile driving prior to March 1, as 
described in the Proposed Mitigation section. Initiating pile driving 
before March 1 is expected to discourage seals from establishing 
birthing lairs near pile

[[Page 43401]]

driving. As such, we expect that this measure will eliminate the 
potential for physical injury to ringed seals during this period. 
Therefore, NMFS expects that the take estimate described herein is 
reasonable even if AGDC must pile drive during their contingency 
period.
    NMFS calculated take using summer densities for all species except 
for bowhead whale. For bowhead whales, NMFS conservatively calculated 
take using the fall density.

                      Table 17--Estimated Level B Harassment Takes by Species, Pile Size and Type, and Installation/Removal Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Calculated level B harassment takes
                                                                Estimated  -----------------------------------------------------------------------------
                           Activity                              duration     Bowhead                    Beluga                   Spotted      Bearded
                                                                  (days)       whale      Gray whale     whale     Ringed seal      seal         seal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           DH4
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sheet Pile...................................................           36        41.65         0.08        11.83       668.04       133.61       113.57
Anchor Pile (11.5-inch H-pile)...............................            9         0.06            0         0.02         0.90         0.18         0.15
Mooring Dolphins (48-inch Pipe Pile).........................           10         2.49            0         0.71        39.98         8.00         6.80
Spud Piles (14-inch H-pile)..................................           12         0.64            0         0.18        10.34         2.07         1.76
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  South Bridge Abutment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock Face (Sheet Pile).......................................           23        26.61         0.05         7.56       426.80        85.36        72.56
Tailwall (Sheet Pile)........................................           23        26.61         0.05         7.56       426.80        85.36        72.56
Anchor Pile (14-inch H-pile).................................            1         0.02            0         0.01         0.34         0.07         0.06
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  North Bridge Abutment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock Face (Sheet Pile).......................................           24        27.76         0.05         7.89       445.36        89.07        75.71
Tailwall (Sheet Pile)........................................           17        19.67         0.04         5.59       315.46        63.09        53.63
Anchor Pile (14-inch H-pile).................................            1         0.02            0         0.01         0.34         0.07         0.06
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Barge Bridge
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mooring Dolphins (48-inch Pipe Piles)........................            4         1.00            0         0.28        15.99         3.20         2.72
Spud Piles (14-inch H-piles).................................            4         0.21            0         0.06         3.45         0.69         0.59
                                                              ------------------------------------------------------------------------------------------
    Total....................................................          164       146.74         0.27        41.69      2,353.8       470.76       400.15
                                                              ------------------------------------------------------------------------------------------
        Level B Harassment Take Proposed for Authorization             123          110        \a\ 2           31        1,765          353          300
         (75% of Total)......................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ 75 percent of the calculated total is 0.2 takes, however, to account for group size (Clarke et al., 2017), NMFS is proposing to authorize two Level
  B harassment takes of gray whale.


                      Table 18--Calculated Level A Harassment Takes by Species, Pile Size and Type, and Installation/Removal Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Calculated level B harassment takes
                                                                Estimated  -----------------------------------------------------------------------------
                           Activity                              duration     Bowhead                    Beluga                   Spotted      Bearded
                                                                  (days)       whale      Gray whale     whale     Ringed seal      seal         seal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           DH4
--------------------------------------------------------------------------------------------------------------------------------------------------------
Sheet Pile...................................................           36            0            0            0         0.01            0            0
Anchor Pile (11.5-inch H-pile)...............................            9         0.69            0         0.20        11.05         2.21         1.88
Mooring Dolphins (48-inch Pipe Pile).........................           10         1.33            0         0.38        21.37         4.27         3.63
Spud Piles (14-inch H-pile)..................................           12            0            0            0            0            0            0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  South Bridge Abutment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock Face (Sheet Pile).......................................           23            0            0            0         0.01            0            0
Tailwall (Sheet Pile)........................................           23            0            0            0         0.01            0            0
Anchor Pile (14-inch H-pile).................................            1         0.05            0         0.02         0.86         0.17         0.15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  North Bridge Abutment
--------------------------------------------------------------------------------------------------------------------------------------------------------
Dock Face (Sheet Pile).......................................           24            0            0            0         0.01            0            0
Tailwall (Sheet Pile)........................................           17            0            0            0            0            0            0
Anchor Pile (14-inch H-pile).................................            1          0.5            0         0.02         0.86         0.17         0.15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Barge Bridge
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mooring Dolphins (48-inch Pipe Piles)........................            4         0.53            0         0.15         8.55         1.71         1.45

[[Page 43402]]

 
Spud Piles (14-inch H-piles).................................            4            0            0            0            0            0            0
                                                              ------------------------------------------------------------------------------------------
    Total....................................................          164         2.65            0         0.77        42.73         8.53         7.26
                                                              ------------------------------------------------------------------------------------------
        Level A Harassment Take Proposed for Authorization             123        \a\ 0            0            0           32            6            5
         (75% of Total)......................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ 75 percent of the calculated total is 1.99 takes, however, we do not expect bowheads to occur within the Level A harassment zone, and we do not
  propose to authorize Level A harassment take of bowhead whale.

    We do not expect bowheads to occur within the Level A harassment 
zones due to the shallow waters (approximately 19 ft. in depth at the 
isopleth). As previously noted, waters less than 15 ft. (4.5 m) deep 
are considered too shallow to support these whales, and in three 
decades of aerial surveys by BOEM (ASAMM), no bowhead whale has been 
recorded in waters less than 16.4 ft (5 m) deep (Clarke and Ferguson 
2010). Therefore, we do not expect Level A harassment of bowhead whales 
to occur, and we do not propose to authorize Level A harassment take of 
bowheads.
    Given the extremely low likelihood of gray whales occurring in the 
Level A harassment zone (as evidenced by the estimated values in Table 
20), we do not expect Level A harassment of gray whales to occur, and 
do not propose to issue any Level A harassment takes of gray whale.
    The largest Level A harassment zone for mid-frequency cetaceans 
(including the beluga whale) extends 56m from the source during impact 
driving of the 48-inch pipe piles (Table 10). Considering the small 
size of the Level A harassment zones, and the low likelihood that a 
beluga will occur in this area, Level A harassment take is unlikely to 
occur. Additionally, AGDC is planning to implement a 50m shutdown zone 
during this activity, which includes the <1 m peak PTS isopleth. We 
expect shutdown zones will eliminate the potential for Level A 
harassment take of beluga whale. Therefore, we are not proposing to 
authorize takes of beluga whale by Level A harassment.

                                    Table 19--Estimated Take by Level A and Level B Harassment, by Species and Stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                              Level A         Level B
                Common name                             Stock               harassment      harassment      Total take         Stock        Percent of
                                                                               take            take                          abundance         stock
--------------------------------------------------------------------------------------------------------------------------------------------------------
Bowhead Whale.............................  Western Arctic..............               0             110             110          16,820            0.65
Gray Whale................................  Eastern North Pacific.......               0               2               2          26,960           0.007
Beluga Whale \a\..........................  Beaufort Sea................               0              31              31          39,258            0.08
                                            Chukchi Sea.................  ..............  ..............  ..............          20,752            0.15
Ringed Seal...............................  Alaska......................              32           1,765           1,797             N/A             N/A
Spotted Seal..............................  Alaska......................               6             353             359         461,625            0.08
Bearded Seal..............................  Alaska......................               5             300             305             N/A             N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ As noted in the Description of Marine Mammals in the Area of Specified Activities section, beluga whales in the project area are likely to be from
  the Beaufort Sea stock. However, we have conservatively attributed all takes to each stock in our analysis.

Effects of Specified Activities on Subsistence Uses of Marine Mammals

    The availability of the affected marine mammal stocks or species 
for subsistence uses may be impacted by this activity. The subsistence 
uses that may be affected and the potential impacts of the activity on 
those uses are described below. Measures included in this IHA to reduce 
the impacts of the activity on subsistence uses are described in the 
Proposed Mitigation section. Last, the information from this section 
and the Proposed Mitigation section is analyzed to determine whether 
the necessary findings may be made in the Unmitigable Adverse Impact 
Analysis and Determination section.
    The communities of Nuiqsut, Utqia[gdot]vik and Kaktovik engage in 
subsistence harvests off the North Slope of Alaska. Alaska Native 
communities have harvested bowhead whales for subsistence and cultural 
purposes with oversight and quotas regulated by the International 
Whaling Commission (IWC). The North Slope Borough (NSB) Department of 
Wildlife Management has been conducting bowhead whale subsistence 
harvest research since the early 1980's to collect the data needed by 
the IWC to set harvest quotas. Bowhead whale harvest (percent of total 
marine mammal harvest), harvest weight, and percent of households using 
bowhead whale are presented in Table 25 of AGDC's application.
    Most of the Beaufort Sea population of beluga whales migrate from 
the Bering Sea into the Beaufort Sea in April or May. The spring 
migration routes through ice leads are similar to those of the bowhead 
whale. Fall migration through the western Beaufort Sea is in September 
or October. Surveys of the fall distribution strongly indicate that 
most belugas migrate offshore along the pack ice front beyond the reach 
of subsistence harvesters. Beluga whales are harvested 
opportunistically during the bowhead harvest and throughout ice-free 
months. No beluga whale harvests were reported in 2006 survey 
interviews conducted by SRBA in any community (SRBA 2010). Beluga 
harvests were also not reported in Nuiqsut and Kaktovik, although

[[Page 43403]]

households did report using beluga whale, likely through sharing from 
other communities (Brown et al., 2016). We do not expect the proposed 
activities at the Alaska LNG project site to affect beluga whale 
subsistence harvests, as none are expected.
    Gray whale harvests were not reported by any of the communities 
surveyed by Alaska Department of Fish and Game (ADF&G) in any of the 
survey years, and therefore are not included as an important 
subsistence species and are not further discussed.
    The community of Utqia[gdot]vik's subsistence activities occur 
outside of the area impacted by activities considered in this 
authorization, and are not discussed further. Please refer to AGDC's 
application for additional information on Utqia[gdot]vik's subsistence 
activities.

Kaktovik

    Kaktovik is the easternmost village in the NSB. Kaktovik is located 
on the north shore of Barter Island, situated between the Okpilak and 
Jago rivers on the Beaufort Sea coast. Kaktovik's subsistence-harvest 
areas are to the east of the project area and target marine mammal 
species migrating eastward during spring and summer occur seaward of 
the project area and westward in the fall.
    Kaktovik bowhead whale hunters reported traveling between Camden 
Bay to the west and Nuvagapak Lagoon to the east (SRBA 2010). This 
range does not include the project area impacted by the activities 
analyzed for this proposed IHA, therefore, Kaktovik bowhead whale 
hunting is not discussed further. Please refer to AGDC's application 
for additional information.
    Ringed, spotted and bearded seals are harvested by the community of 
Kaktovik. Residents hunt seals in rivers during ice-free months, 
primarily July-August. Ringed seals are an important subsistence 
resource for Native Alaskans living in communities along the Beaufort 
Sea coast. Kaktovik hunters travel by boat to look for ringed seals on 
floating ice (often while also hunting for bearded seal) or sometimes 
along the ice edge by snow machine before break-up, during the spring 
(SRBA 2010). In 2006, 7 people (18 percent of survey respondents) 
indicated that they had recently hunted for ringed seals in Kaktovik 
(SRBA 2010). Residents reported looking for ringed seal, usually while 
also searching for bearded seal, offshore between Prudhoe Bay to the 
west and Demarcation Bay to the east (SRBA 2010). Ringed seal hunting 
typically peaks between March and August but continues into September, 
as well (SRBA 2010). Although residents reported hunting ringed seals 
up to approximately 30 mi (48 km) from shore, the highest numbers of 
overlapping use areas generally occur within a few miles from shore 
(SRBA 2010). The total use area for ringed seal from 1995-2006 
encompassed approximately 2,139 mi\2\. Harvest of ringed seals by 
Kaktovik hunters does not typically occur to the west of Camden Bay and 
therefore is not expected to be affected by Alaska LNG project 
activities.
    Kaktovik hunters harvested 126 pounds of spotted seals in 1992 
(ADF&G CSIS; retrieved and analyzed August 15, 2018). Spotted seals 
were not reported harvested in 2006 survey interviews conducted in 
Nuiqsut (SRBA 2010).
    Kaktovik bearded seal hunting occurs along the coast as far west as 
Prudhoe Bay and as far east as the United States/Canada border (SRBA 
2010). Residents reported looking for bearded seal as far as 
approximately 30 mi (48 km) from shore, but generally hunt them closer 
to shore, up to 5 mi (8 km; SRBA 2010). Between 1994-2003, 29 bearded 
seals were taken in Kaktovik. In 2006, 7 people (18 percent of survey 
respondents) indicated that they had recently hunted for bearded seals 
in Kaktovik (SRBA 2010). Bearded seal hunting activities, like ringed 
seal, begin in March, peaking in July and August, and then conclude in 
September (SRBA 2010).
    The community of Kaktovik is approximately 100 (direct) mi (160 km) 
from the proposed project at Prudhoe Bay; subsistence activities for 
these communities primarily occur outside of the project construction 
area and associated Level A and Level B harassment zones. The planned 
construction and use of improvements to West Dock would occur in 
Prudhoe Bay, adjacent to existing oil and gas infrastructures, and in 
an area that is not typically used for subsistence other than extremely 
limited bearded seal hunting by residents of Kaktovik.
    Because of the distance from Kaktovik and Kaktovik's very limited 
use of waters offshore of Prudhoe Bay, and because the proposed 
activities would occur in an already-developed area, it is unlikely 
that the proposed activities would have any effects on the use of 
marine mammals for subsistence by residents of Kaktovik. Therefore, we 
do not discuss Kaktovik's subsistence activities further.

Nuiqsut

    The proposed construction activities would occur closest to the 
marine subsistence use area used by the Native Village of Nuiqsut. 
Nuiqsut is located on the west bank of the Nechelik Channel on the 
lower Colville River, about 25 mi (40 km) from the Arctic Ocean and 
approximately 150 mi (242 km) southeast of Utqia[gdot]vik. Nuiqsut 
subsistence hunters utilize an extensive search area, spanning 16,322 
mi\2\ (km\2\) across the central Arctic Slope (see Figure 19 of AGDC's 
application, Brown et al., 2016). Marine mammal hunting is primarily 
concentrated in two areas: (1) Harrison Bay, between Atigaru Point and 
Oliktok Point, including a northward extent of approximately 50 mi (80 
km) beyond the Colville River Delta (Brown et al., 2016); and (2) east 
of the Colville River Delta between Prudhoe and Foggy Island bays, 
which includes an area of approximately 100 square mi surrounding the 
Midway Islands, McClure Island and Cross Island (Brown et al., 2016). 
The community of Nuiqsut uses subsistence-harvest areas adjacent to the 
proposed construction area; however, West Dock is not a common hunting 
area, nor is it visited regularly by Nuiqsut subsistence hunters 
primarily because of its industrial history.
    Ringed, spotted and bearded seals are also harvested by the 
community of Nuiqsut. Seal hunting typically begins in April and May 
with the onset of warmer temperatures. Many residents continue to hunt 
seals after spring breakup as well (Brown et al., 2016).
    The most important seal hunting area for Nuiqsut hunters is off the 
Colville Delta, an area extending as far west as Fish Creek and as far 
east as Pingok Island. Seal hunting search areas by Nuiqsut hunters 
also included Harrison Bay, and a 30-mi (48-km) stretch northeast of 
Nuiqsut between the Colville and Kuparuk rivers, near Simpson Lagoon 
and Jones Islands (Brown et al., 2016). Cross Island is a productive 
area for seals, but is too far from Nuiqsut to be used on a regular 
basis. Seal subsistence use areas of Nuiqsut from 1995 through 2006 are 
depicted in Figure 21 of AGDC's application.
    Ringed seals are an important subsistence resource for Native 
Alaskans living in communities along the Beaufort Sea coast. Nuiqsut 
residents commonly harvest ringed seal in the Beaufort Sea during the 
summer months (SRBA 2010). There are a higher number of use areas 
extending east and west of the Colville River delta. Residents reported 
traveling as far as Cape Halkett to the west and Camden Bay to the east 
in search of ringed seal. Survey respondents reported traveling 
offshore up to 30 mi (48 km; SRBA 2010). Residents reported hunting

[[Page 43404]]

ringed seals throughout the late spring, summer, and early fall with a 
higher number of use areas reported in June, July, and August (SRBA 
2010). In 2006, 12 people (36 percent of survey respondents) indicated 
that they had recently hunted for ringed seals in Nuiqsut (SRBA 2010).
    Nuiqsut bearded seal use areas extend as far west as Cape Halkett, 
as far east as Camden Bay, and offshore up to 40 mi (64 km). In 2006, 
12 people (69 percent of survey respondents) indicated that they had 
recently hunted for bearded seals in Nuiqsut (SRBA 2010). Nuiqsut 
hunters reported hunting bearded seal during the summer season in open 
water as the seals are following the ice pack. Residents reported 
hunting bearded seal between June and September, although a small 
number of use areas were reportedly used in May and October (SRBA 
2010). The number of reported bearded seal use areas peak in July and 
August, when the majority of seals are available along the ice pack 
(SRBA 2010).
    Nuiqsut's bowhead whale hunt occurs in the fall at Cross Island, a 
barrier island located approximately 12 mi (19 km) northwest of West 
Dock. Nuiqsut whalers base their activities from Cross Island 
(Galginaitis 2014), and the whaling search and the harvest areas 
typically are concentrated north of the island. Hunting activities 
between 1997 and 2006 occurred almost as far west as Thetis Island, as 
far east as Barter Island (Kaktovik), and up to approximately 50 mi (80 
km) offshore (SRBA 2010). Harvest locations in 1973-2011 and GPS tracks 
of 2001-2011 whaling efforts are shown in Figure 19 of AGDC's 
application.
    Bowhead whales are harvested by Nuiqsut whalers during the fall 
whaling season. Nuiqsut residents typically hunt bowhead whales in 
September, although a small number of use areas were reported in August 
and extending into October (Stephen R. Braund & Associates [SRBA] 
2010). Pile driving will not occur during Nuiqsut whaling.
    Nuiqsut subsistence hunting crews operating from Cross Island have 
harvested three to four bowhead whales per year (Bacon et al., 2009; 
Galginaitis 2014). In 2014, the Alaska Eskimo Whaling Commission (AEWC) 
allocated Nuiqsut a quota of four bowhead whales each year; however, 
through transfers of quota from other communities, in 2015 Nuiqsut was 
able to harvest five whales (Brown et al., 2016). In 2006, 10 people 
(30 percent of survey respondents) in Nuiqsut indicated that they had 
recently hunted for bowhead whales (SRBA 2010). In 2016, Nuiqsut 
whaling crews harvested four bowhead whales (Suydam et al., 2017).
    Nuiqsut is 70 mi (112 km) away from the proposed project, and is 
likely to be the community that has the greatest potential to 
experience any impacts to subsistence practices. The primary potential 
for AK LNG project impacts to Nuiqsut's subsistence use of marine 
mammals is associated with barge activity, which could interfere with 
summer seal and fall bowhead whale hunting (Alaska LNG 2016). Barge 
activity is beyond the scope of this IHA, but noise associated with 
barging could deflect bowhead whales as they migrate through Nuiqsut's 
fall whaling grounds or cause temporary disturbances of seals, making 
successful harvests more difficult. Barge traffic would occur from July 
through September. Although barging activities would not cease during 
Nuiqsut's fall bowhead whale hunting activities, the potential for 
impact would be greatly reduced by keeping project vessels landward of 
Cross Island during the August 25-September 15 period, avoiding the 
high use areas offshore of the island during the entire whaling season 
in most years (Alaska LNG 2016, 2017).
    Pile driving associated with construction at West Dock could also 
affect subsistence hunting of bowhead whales, as the Level B harassment 
zones extend up to 4.6 km from the pile driving site for some pile and 
hammer type combinations. As such, AGDC will not pile drive during the 
Nuiqsut whaling season (see Proposed Mitigation). AGDC has consulted 
with AEWC and NSB on mitigation measures to limit impacts (Alaska LNG 
2016), and has continued to provide formal and informal project updates 
to these groups, as recently as February 2020 and May 2020.
    The planned activities are not expected to impact marine mammals in 
numbers or locations sufficient to render them unavailable for 
subsistence harvest given the short-term, temporary, and localized 
nature of construction activities, and the proposed mitigation 
measures. Impacts to marine mammals would mostly include limited, 
temporary behavioral disturbances of seals, however, some PTS is 
possible. Serious injury or mortality of marine mammals is not 
anticipated from the proposed activities, and the activities are not 
expected to have any impacts on reproductive or survival rates of any 
marine mammal species.
    In summary, impacts to subsistence hunting are not expected due to 
the distance between West Dock construction and primary seal hunting 
areas, and proposed mitigation during the Nuiqsut bowhead whale hunt.

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

    In addition to the measures described later in this section, AGDC 
will employ the following mitigation measures:
     Conduct briefings between construction supervisors and 
crews and the marine mammal monitoring team prior to the start of all 
pile driving

[[Page 43405]]

activity and when new personnel join the work, to explain 
responsibilities, communication procedures, marine mammal monitoring 
protocol, and operational procedures;
     For in-water heavy machinery work other than pile driving, 
if a marine mammal comes within 10 m, operations shall cease and 
vessels shall reduce speed to the minimum level required to maintain 
steerage and safe working conditions;
     For those marine mammals for which Level B harassment take 
has not been requested, in-water pile installation/removal will shut 
down immediately when it is safe to do so if such species are observed 
within or entering the Level B harassment zone; and
     If take reaches the authorized limit for an authorized 
species, pile installation will be stopped as these species approach 
the Level B harassment zone to avoid additional take.

                          Table 20--Shutdown Zones During Pile Installation and Removal
----------------------------------------------------------------------------------------------------------------
                                                                             Shutdown zone (m)
             Activity                    Hammer type      ------------------------------------------------------
                                                                LF cetaceans       MF cetaceans       Phocids
----------------------------------------------------------------------------------------------------------------
11.5-inch H-Pile..................  Impact...............  1,200................              50             500
14-inch H-Pile....................  Impact...............  1,200................              50             500
                                    Vibratory............  10...................              10              10
48-inch Pipe Pile.................  Impact...............  1,600................              50             500
Sheet Piles.......................  Vibratory............  20...................              10              10
----------------------------------------------------------------------------------------------------------------

    AGDC is required to implement all mitigation measures described in 
the biological opinion (issued on June 3, 2020).
    The following mitigation measures would apply to AGDC's in-water 
construction activities.
    Establishment of Shutdown Zones--AGDC will establish shutdown zones 
for all pile driving and removal activities. The purpose of a shutdown 
zone is generally to define an area within which shutdown of the 
activity would occur upon sighting of a marine mammal (or in 
anticipation of an animal entering the defined area). Shutdown zones 
will vary based on the activity type and marine mammal hearing group 
(see Table 20). The largest shutdown zones are generally for low 
frequency cetaceans as shown in Table 20. In this instance, the largest 
shutdown zone for low frequency cetaceans is 1,600 m. AGDC expects that 
they will be able to effectively observe phocids at distances up to 500 
m, large cetaceans at 2-4 km, and belugas at 2-3 km.
    The placement of protected species observers (PSOs) during all pile 
driving and removal activities (described in detail in the Proposed 
Monitoring and Reporting section) will ensure that the entire shutdown 
zone is visible during pile installation. If visibility degrades to 
where the PSO determines that they cannot effectively monitor the 
entire shutdown zone during pile driving, the applicant may continue to 
drive the pile section that was being driven to its target depth when 
visibility degraded to unobservable conditions, but will not drive 
additional sections of pile. Pile driving may continue during low light 
conditions to allow for the evaluation of night vision and infrared 
sensing devices.
    Monitoring for Level A and Level B Harassment--AGDC will monitor 
the Level B harassment zones (areas where SPLs are equal to or exceed 
the 160 dB rms threshold for impact driving and the 120 dB rms 
threshold during vibratory driving) and Level A harassment zones, to 
the extent practicable. Monitoring zones provide utility for observing 
by establishing monitoring protocols for areas adjacent to the shutdown 
zones. Monitoring zones enable observers to be aware of and communicate 
the presence of marine mammals in the project area outside the shutdown 
zone and thus prepare for a potential shutdown of activity should the 
animal enter the shutdown zone. Placement of PSOs on elevated 
structures on West Dock will allow PSOs to observe phocids within the 
Level A and Level B harassment zones, to an estimated distance of 500 
m. However, due to the large Level A and Level B harassment zones 
(Table 10), PSOs will not be able to effectively observe the entire 
zones during all activities. Therefore, marine mammal exposures will be 
recorded and extrapolated based upon the number of observed exposures 
and the percentage of the Level A or Level B harassment zone that was 
not visible.
    Pre-activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving or removal 
of 30 minutes or longer occurs, PSOs will observe the shutdown and 
monitoring zones for a period of 30 minutes. If a marine mammal is 
observed within the shutdown zone, a soft-start cannot proceed until 
the animal has left the zone or has not been observed for 15 minutes 
(pinnipeds) or 30 minutes (cetaceans). When a marine mammal for which 
Level B harassment take is authorized is present in the Level B 
harassment zone, activities may begin and Level B harassment take will 
be recorded. If the entire Level B harassment zone is not visible at 
the start of construction pile driving or removal activities can begin. 
If work ceases for more than 30 minutes, the pre-activity monitoring of 
both the Level B harassment zone and shutdown zones will commence.
    Nighttime Monitoring--PSOs will use night vision devices (NVDs) and 
infrared (IR) for nighttime and low visibility monitoring. AGDC will 
select devices for monitoring, and will test the devices to determine 
the efficacy of the monitoring equipment and technique. For a detailed 
explanation of AGDC's plan to test the NVDs and IR equipment, please 
see AGDC's 4MP, available online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable (Please note that AGDC will not assess 
object detection at distance intervals using buoys as stated in the 
4MP. Rather, they will test object detection on land using existing 
landmarks at known distances from PSOs, such as road signs.)
    Soft Start--Soft-start procedures are believed to provide 
additional protection to marine mammals by providing warning and/or 
giving marine mammals a chance to leave the area prior to the hammer 
operating at full capacity. For impact pile driving, contractors will 
be required to provide an initial set of three strikes from the hammer 
at reduced energy, followed by a 30-second waiting period. This 
procedure will be conducted three times before impact pile driving 
begins. Soft

[[Page 43406]]

start will be implemented at the start of each day's impact pile 
driving and at any time following cessation of impact pile driving for 
a period of thirty minutes or longer.
    Pile Driving During Contingency Period--In the event that AGDC must 
continue pile driving or removal during their contingency period 
(February-April 2023), AGDC must begin pile driving before March 1, the 
known onset of ice seal lairing season. Initiating pile driving before 
March 1 is expected to discourage seals from establishing birthing 
lairs near pile driving. Additionally, a subsistence advisor would 
survey areas within a buffer zone of DH4 where water depth is greater 
than 10 ft. (3 m) to identify potential ringed seal structures before 
activity begins. Construction crews would avoid identified ice seal 
structures by a minimum of 500 ft. (150 m).
    AGDC does not plan to use a bubble curtain or other sound 
attenuation device. Given the shallow water in the project area, bubble 
curtains would be very difficult to deploy, and may not result in 
significant sound reduction.

Mitigation for Subsistence Uses of Marine Mammals or Plan of 
Cooperation

    Regulations at 50 CFR 216.104(a)(12) further require IHA applicants 
conducting activities in or near a traditional Arctic subsistence 
hunting area and/or that may affect the availability of a species or 
stock of marine mammals for Arctic subsistence uses to provide a Plan 
of Cooperation or information that identifies what measures have been 
taken and/or will be taken to minimize adverse effects on the 
availability of marine mammals for subsistence purposes. A plan must 
include the following:
     A statement that the applicant has notified and provided 
the affected subsistence community with a draft plan of cooperation;
     A schedule for meeting with the affected subsistence 
communities to discuss proposed activities and to resolve potential 
conflicts regarding any aspects of either the operation or the plan of 
cooperation;
     A description of what measures the applicant has taken 
and/or will take to ensure that proposed activities will not interfere 
with subsistence whaling or sealing; and
     What plans the applicant has to continue to meet with the 
affected communities, both prior to and while conducting the activity, 
to resolve conflicts and to notify the communities of any changes in 
the operation.
    AGDC provided a draft Plan of Cooperation (POC) to NMFS on March 
27, 2019. The POC outlines AGDC's extensive coordination with 
subsistence communities that may be affected by the AK LNG project. It 
includes a description of the project, community outreach that has 
already been conducted, and project mitigation measures. AGDC will 
continue coordination with subsistence communities throughout the 
project duration. The POC is a live document and will be updated 
throughout the project review and permitting process. AGDC's draft POC 
is available on our website at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
    AGDC continues to document its communications with the North Slope 
subsistence communities, as well as the substance of its communications 
with subsistence stakeholder groups, and has developed mitigation 
measures that include measures suggested by community members as well 
as industry standard measures. AGDC will continue to routinely engage 
with local communities and subsistence groups. Multiple user groups are 
often consulted simultaneously as part of larger coalition meetings 
such as the Arctic Safety Waterways Committee meetings. Local 
communities and subsistence groups identified by AGDC are listed in the 
POC. AGDC will develop a Communication Plan and will implement this 
plan before initiating construction operations to coordinate activities 
with local subsistence users, as well as Village Whaling Captains' 
Associations, to minimize the risk of interfering with subsistence 
hunting activities, and keep current as to the timing and status of the 
bowhead whale hunt and other subsistence hunts. A project informational 
mailer with a request for community feedback (traditional mail, email, 
phone) will be sent to community members prior to construction. 
Following the construction season, AGDC intends to have a post-season 
co-management meeting with the commissioners and committee heads to 
discuss results of mitigation measures and outcomes of the preceding 
season. The goal of the post-season meeting is to build upon the 
knowledge base, discuss successful or unsuccessful outcomes of 
mitigation measures, and possibly refine plans or mitigation measures 
if necessary.
    The AEWC works annually with industry partners to develop a 
Conflict Avoidance Agreement (CAA). This agreement implements 
mitigation measures that allow industry to conduct their work in or 
transiting the vicinity of active subsistence hunters, in areas where 
subsistence hunters anticipate hunting, or in areas that are in 
sufficient proximity to areas expected to be used for subsistence 
hunting where the planned activities could potentially adversely affect 
the subsistence bowhead whale hunt through effects on bowhead whales, 
while maintaining the availability of bowheads for subsistence hunters. 
One key aspect of the CAA is the inclusion of time and area closures. 
AGDC is considering whether it would enter into a CAA or similar 
agreement with the AEWC and will discuss and evaluate a CAA in the 
aforementioned meetings.
    AGDC will not conduct pile driving during the Nuiqsut whaling 
season in an effort to eliminate effects on the availability of bowhead 
whales for subsistence hunting that could occur as a result of project 
noise. Nuiqsut whaling is approximately August 25-September 15, though 
the exact dates may change.
    Barging activities could potentially impact Nuiqsut's fall bowhead 
whale hunt and possibly other marine mammal harvest activities in the 
Beaufort Sea. As mentioned previously, barging activities are beyond 
the scope of this IHA, and no take is expected to occur as a result of 
barging activities. However, NMFS notes that AGDC will limit barges to 
waters shoreward of Cross Island during the Nuiqsut whaling season 
(approximately August 25-September 15) in an effort to avoid any 
potential impacts on subsistence uses. AGDC has consulted with AEWC and 
NSB on mitigation measures to limit impacts (Alaska LNG 2016), and has 
continued to provide formal and informal project updates to these 
groups, as recently as February 2020 and May 2020. As noted previously, 
AGDC's construction activities at West Dock do not overlap with the 
areas where subsistence hunters typically harvest ice seals, therefore, 
these activities are not expected to impact subsistence hunts of ice 
seals.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means 
effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance, and on the 
availability of such species or stock for subsistence uses.

[[Page 43407]]

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:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    Marine mammal monitoring must be conducted in accordance with the 
Marine Mammal Monitoring Plan, available online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-other-energy-activities-renewable. Marine mammal 
monitoring during pile driving and removal must be conducted by NMFS-
approved PSOs in a manner consistent with the following:
     Independent PSOs (i.e., not construction personnel) who 
have no other assigned tasks during monitoring periods must be used;
     Where a team of three or more PSOs are required, a lead 
observer or monitoring coordinator must be designated. The lead 
observer must have prior experience working as a marine mammal observer 
during construction;
     Other PSOs may substitute education (degree in biological 
science or related field) or training for experience. PSOs may also 
substitute Alaska native traditional knowledge for experience. (NMFS 
recognizes that PSOs with traditional knowledge may also have prior 
experience, and therefore be eligible to serve as the lead PSO.); and
     AGDC must submit PSO CVs for approval by NMFS prior to the 
onset of pile driving.
    PSOs should have the following additional qualifications:
     Ability to conduct field observations and collect data 
according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     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, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
     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.
    At least two PSOs will be present during all pile driving/removal 
activities. PSOs will have an unobstructed view of all water within the 
shutdown zone. PSOs will observe as much of the Level A and Level B 
harassment zone as possible. PSO locations are as follows:
    i. Dock Head 4--During impact pile driving at DH4, two PSOs must be 
stationed to view toward the east, north, and west of the seawater 
treatment plant. During vibratory pile driving at DH4, two PSOs must 
monitor from each PSO location (four PSOs); and
    ii. Barge Bridge--During work at the barge bridge, two PSOs must be 
stationed at the north end of the bridge.
    PSOs will be stationed on elevated platforms at DH4, and on the 
elevated bridge during work at the barge bridge. They will possess the 
equipment described in the 4MP, including NVDs during nighttime 
monitoring. However, during the primary construction season, nighttime 
on the North Slope will be brief. Given the elevated PSO sites and 
equipment, AGDC expects that they will be able to effectively observe 
phocids at distances up to 500 m, large cetaceans at 2-4 km, and 
belugas at 2-3 km, however, PSOs will not be able to effectively 
observe the entire area of the Level A (seals only) or Level B 
harassment zones during all pile driving activities.
    PSOs will begin monitoring three days prior to the onset of pile 
driving and removal activities and continue through three days after 
completion of the pile driving and removal activities. PSOs will 
monitor 24 hours per day, even during periods when construction is not 
occurring. In addition, observers shall record all incidents of marine 
mammal occurrence, regardless of distance from activity, and shall 
document any behavioral reactions in concert with distance from piles 
being driven or removed. Pile driving activities include the time to 
install or remove a single pile or series of piles, as long as the time 
elapsed between uses of the pile driving equipment is no more than 30 
minutes.

Acoustic Monitoring

    AGDC will deploy a single, archival passive acoustic monitoring 
(PAM) receiver in the far field to collect data that indicates the 
gross presence of marine mammals and the received sound source level at 
distance during construction.
Reporting
    A draft marine mammal monitoring report will be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. The report will include an overall description of work 
completed, a narrative regarding marine mammal sightings, and 
associated PSO data sheets. Specifically, the report must include:
     Dates and times (begin and end) of all marine mammal 
monitoring;
     Construction activities occurring during each daily 
observation period, including precise start and stop time of

[[Page 43408]]

each type of construction operation mode, how many and what type of 
piles were driven or removed and by what method (i.e., impact or 
vibratory);
     Total number of hours during which each construction 
activity type occurred.
     Total number of hours that PSOs were on duty during each 
construction activity, and total number of hours that PSOs were on duty 
during periods of no construction activity;
     Weather parameters and water conditions during each 
monitoring period (e.g., wind speed, percent cover, visibility, sea 
state), and number of hours of observation that occurred during various 
visibility and sea state conditions.
     The number of marine mammals observed, by species and 
operation mode, relative to the pile location;
     The number of marine mammals observed (including periods 
with no construction).
     Distances and bearings of each marine mammal observed to 
the pile being driven or removed for each sighting (if pile driving or 
removal was occurring at time of sighting).
     Age and sex class, if possible, of all marine mammals 
observed;
     PSO locations during marine mammal monitoring, including 
elevation above sea level;
     Distances and bearings of each marine mammal observed to 
the pile being driven or removed for each sighting (if pile driving or 
removal was occurring at time of sighting);
     Description of any marine mammal behavior patterns during 
observation, including direction of travel and estimated time spent 
within the Level A and Level B harassment zones while the source was 
active;
     Number of individuals of each species (differentiated by 
month as appropriate) detected within the monitoring zone, and 
estimates of number of marine mammals taken, by species (a correction 
factor may be applied to total take numbers, as appropriate);
     Histograms of perpendicular distances to PSO sightings, by 
species (or species group if sample sizes are small);
     Sighting rates summarized into daily or weekly periods for 
the before, during, and after construction periods;
     Maps showing visual and acoustic detections by species and 
construction activity type.
     Detailed information about any implementation of any 
mitigation triggered (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting behavior of the animal, if 
any;
     Description of attempts to distinguish between the number 
of individual animals taken and the number of incidences of take, such 
as ability to track groups or individuals;
     An extrapolation of the estimated takes by Level A and 
Level B harassment based on the number of observed exposures within the 
Level A and Level B harassment zone and the percentages of the Level A 
and Level B harassment zones that were not visible; and
     Submit all PSO datasheets and/or raw sighting data (in a 
separate file from the Final Report referenced immediately above).
    If no comments are received from NMFS within 30 days, the draft 
report will constitute the final report. If comments are received, a 
final report addressing NMFS comments must be submitted within 30 days 
after receipt of comments.
    AGDC's acoustic monitoring report must include the number of marine 
mammal detections (including species, date and time of detection, and 
type of pile driving underway, if applicable), the received sound 
levels from pile driving activity, and the following hydrophone 
equipment and method information: Recording devices, sampling rate, 
sensitivity of the PAM equipment, locations of the hydrophones, duty 
cycle, distance (m) from the pile where recordings were made, depth of 
recording devices, depth of water in area of recording devices.
    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the IHA-holder shall report 
the incident to the Office of Protected Resources (OPR) (301-427-8401), 
NMFS and to the Alaska regional stranding coordinator (907-586-7209) as 
soon as feasible. If the death or injury was clearly caused by the 
specified activity, the IHA-holder must immediately cease the specified 
activities until NMFS is able to review the circumstances of the 
incident and determine what, if any, additional measures are 
appropriate to ensure compliance with the terms of the IHA. The IHA-
holder must not resume their activities until notified by NMFS.
    The report must include the following information:
     Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
     Species identification (if known) or description of the 
animal(s) involved;
     Condition of the animal(s) (including carcass condition if 
the animal is dead);
     Observed behaviors of the animal(s), if alive;
     If available, photographs or video footage of the 
animal(s); and
     General circumstances under which the animal was 
discovered.

Monitoring Plan Peer Review

    The MMPA requires that monitoring plans be independently peer 
reviewed where the proposed activity may affect the availability of a 
species or stock for taking for subsistence uses (16 U.S.C. 
1371(a)(5)(D)(ii)(III)). Regarding this requirement, NMFS' implementing 
regulations state that upon receipt of a complete monitoring plan, and 
at its discretion, NMFS will either submit the plan to members of a 
peer review panel for review or within 60 days of receipt of the 
proposed monitoring plan, schedule a workshop to review the plan (50 
CFR 216.108(d)).
    NMFS established an independent peer review panel to review AGDC's 
Monitoring Plan for the proposed project in Prudhoe Bay. NMFS provided 
AGDC's monitoring plan to the Peer Review Panel (PRP) and asked them to 
answer the following questions:
    1. Will the applicant's stated objectives effectively further the 
understanding of the impacts of their activities on marine mammals and 
otherwise accomplish the goals stated below? If not, how should the 
objectives be modified to better accomplish the goals below?
    2. Can the applicant achieve the stated objectives based on the 
methods described in the plan?
    3. Are there technical modifications to the proposed monitoring 
techniques and methodologies proposed by the applicant that should be 
considered to better accomplish the objectives?
    4. Are there techniques not proposed by the applicant (i.e., 
additional monitoring techniques or methodologies) that should be 
considered for inclusion in the applicant's monitoring program to 
better accomplish the objectives?
    5. What is the best way for an applicant to present their data and 
results (formatting, metrics, graphics, etc.) in the required reports 
that are to be submitted to NMFS (i.e., 90-day report)?
    The peer review panel (PRP) met in March 2020 and subsequently 
provided a final report to NMFS containing recommendations that the 
panel members felt were applicable to AGDC's monitoring plan. The panel 
concluded that the objectives are appropriate,

[[Page 43409]]

however they provided some recommendations to improve AGDC's ability to 
achieve their stated objectives. The PRP's primary recommendations and 
comments are summarized and addressed below. The PRP's full report is 
available on our website at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.
    The PRP recommended that AGDC station PSOs on elevated platforms to 
increase sighting distance. NMFS agrees and proposes to require AGDC to 
provide elevated monitoring locations for PSOs. The structures would 
vary depending on the construction location.
    The PRP recommended that PSOs focus on scanning the shoreline and 
water, alternately with visual scans and using binoculars, to detect as 
many animals as possible rather than following individual animals for 
any length of time to collect detailed behavioral information. NMFS 
requires PSOs to document and report the behavior of marine mammals 
observed within the Level A and Level B harassment zones. While NMFS 
agrees that PSOs should not document behavior at the expense of 
detecting other marine mammals, particularly within the shutdown zone, 
we are asking PSOs to record an estimate of the amount of time that an 
animal spends in the harassment zone, which is important to help 
understand the likelihood of incurring PTS (given the duration 
component of the thresholds) and the severity of behavioral 
disturbance.
    The PRP recommended that the PSOs record visibility conditions at 
regular intervals (e.g., every five minutes) and as they change 
throughout the day. The panel recommended using either laser range 
finders or a series of ``landmarks'' at varying distances from each 
observer. The PRP notes that if AGDC uses landmarks, AGDC could measure 
the distance to the landmarks on the ground before pile driving or 
removal begins, and reference these landmarks throughout the season to 
record visibility. The landmarks could be buildings, signs, or other 
stationary objects on land that are located at increasing distances 
from each observation platform. PSOs should record visibility according 
to the farthest landmark the laser range finder can detect or that the 
PSO can clearly see. NMFS will require AGDC to record visibility 
conditions throughout construction; however, NMFS will require PSOs to 
record visibility every 30 minutes, rather than every five minutes, in 
an effort to minimize distraction from observing marine mammals. PSOs 
will be equipped with range finders, and will establish reference 
landmarks on land.
    The PRP recommended that AGDC have a designated person on site 
keeping an activity log that includes the precise start and stop dates 
and times of each type of construction operation mode. AGDC's field 
lead PSO will record this information during construction.
    The PRP commended AGDC's proposed use and experimentation with 
night vision devices (NVD) and infrared technology. The panel noted 
that there are many devices with a broad range of capabilities that 
should be thoroughly understood before the experiment is conducted. 
AGDC will select the most effective devices based on surveys of 
experienced PSOs and literature provided by the panel.
    The PRP expressed concern about the limited effective visual 
detection range of the PSOs in comparison with the estimated size of 
the Level A and Level B harassment zones, including AGDC's ability to 
shut down at the proposed distances, and AGDC's ability to estimate 
actual Level A and Level B harassment takes. The panel noted that 
effective sighting distances are likely 200 m for seals, and 1 km for 
mysticetes, based on ship-based PSO observations in the Chukchi Sea 
(LGL et al., 2011). They noted that the effective sighting distance for 
beluga whales may be greater than 200 m, although visibility would 
likely decrease in windy conditions with white caps (DeMaster et al., 
2001). The panel recommended that AGDC implement real-time PAM to 
verify the harassment zone sizes, and to improve detection of marine 
mammals at distances where visual detection probability is limited or 
not possible. The panel recommended that AGDC begin PAM two to three 
weeks prior to the start of construction and continue through two to 
three weeks after construction activities conclude for the season. They 
recommended archival bottom mounted recorders as an alternative to 
real-time PAM, but noted that these setups are not as easy to relocate 
and that data can only be accessed after recovery.
    In a related comment, the panel recommended that AGDC report total 
estimated Level A and Level B harassment takes using two methods. 
First, the panel recommended that AGDC assume that animal density is 
uniform throughout the Level B harassment zone and use distance 
sampling methods, such as Burt et al., 2014, based only on the shore-
based PSO observations to estimate actual takes by Level B harassment. 
Second, the PRP recommended that AGDC also use real-time PAM to 
estimate takes by Level B harassment only in the far field, assuming 
that each acoustic detection that occurs during pile driving or removal 
is a Level B harassment take.
    In consideration of the effective sighting distances included in 
the PRP report, and estimated effective sighting distances from the 
applicant, NMFS has decreased the planned shutdown zone for phocids 
during impact pile driving to 500 m, as proposed herein. While this 
distance is greater than the 200 m estimated by the PRP, shore-based 
PSOs typically have greater visibility. Additionally, AGDC's PSOs will 
observe from elevated locations.
    NMFS does not propose to require AGDC to report Level A and Level B 
harassment takes using distance sampling methods, as NMFS does not 
believe that it is appropriate to apply precise distance sampling 
methods intended for systematic surveys to estimating take numbers in 
this situation. As noted by the panel, the assumption of uniform 
density throughout the Level A and Level B harassment zone is likely 
violated in this instance, and the pile driving and removal activities 
are likely to further affect the distribution within the zones. 
Therefore, NMFS proposes to require AGDC to include an extrapolation of 
the estimated takes by Level A and Level B harassment based on the 
number of observed exposures within the Level A or Level B harassment 
zone and the percentage of the Level A or Level B harassment zone that 
was not visible in their final report.
    NMFS does not propose to require AGDC to implement real-time PAM. 
However, NMFS proposes to require AGDC to include a single, archival 
PAM receiver in the far field to collect data that indicates the gross 
presence of marine mammals and the received sound source level at 
distance. AGDC will implement the majority, if not all, of the proposed 
pile driving and removal during the open water season. Since AGDC would 
need to deploy the PAM system after ice melt, deploying it two to three 
weeks before and after the construction period would narrow AGDC's open 
water work window by at least one month. Additionally, while AGDC's 
construction is occurring within a limited timeframe, other companies 
have operations in the area also, which may interfere with the ability 
to gather baseline data regarding marine mammal presence without 
interference from other industrial activities. Marine mammals in the 
project area are migratory, so presence within the work area would 
change

[[Page 43410]]

throughout the suggested monitoring period, even if AGDC was not 
conducting the activity. As such, NMFS will require AGDC to deploy the 
archival PAM receiver for the duration of the active construction 
period only.
    We do not expect marine mammals within the project area to be 
particularly vocal, given that the project is primarily during the open 
water season, outside of the breeding period. The operation of real-
time PAM is significantly more costly than collecting PAM data for 
later analyses, as someone would need to monitor the data in real-time, 
and the PAM buoys would need to be relocated for changes in monitoring 
zone sizes between various pile sizes and installation or removal 
methods. Real-time PAM would be helpful if there were a necessity to 
take an action, such as shutting down operations, at the time that a 
detection occurs. However, in this instance, visual monitoring by PSOs 
can adequately minimize Level A harassment take, and the proposed 
authorization includes Level A harassment take of ice seals. Given the 
limitations described above, implementation of real-time PAM is not 
warranted in light of the associated cost and effort.
    The PRP also recommended that PSOs observations begin 2-3 weeks 
prior to construction, continue through the construction season, and 
continue for 2-3 weeks after the construction season ends. Given that 
ice conditions in the weeks leading up to the construction period will 
differ from that during construction (as will ice seal presence), NMFS 
will require PSOs to observe from shore during the three days before 
construction begins, and for three additional days after the 
construction season ends, rather than 2-3 weeks. During the 
construction season, NMFS will require PSOs to monitor 24 hours per 
day, even during periods without construction.
    The PRP also made recommendations regarding how AGDC should present 
their monitoring data and results. Please refer to part V of the report 
for those suggestions. AGDC will implement the reporting 
recommendations that do not require PAM as stated in the 
recommendations. NMFS is still considering whether reporting 
recommendations h-j are appropriate.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), as well as effects on habitat, and the likely effectiveness 
of the mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    To avoid repetition, the majority of our analyses apply to all of 
the species listed in Table 19, 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 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.
    Pile driving and removal activities associated with the project, as 
outlined previously, have the potential to disturb or displace marine 
mammals. Specifically, the specified activities may result in take, in 
the form of Level A and Level B harassment, from underwater sounds 
generated from pile driving and removal. Potential takes could occur if 
individuals of these species are present in zones ensonified above the 
thresholds for Level A or Level B harassment, identified above, when 
these activities are underway. While AGDC may pile drive at any time of 
day (24 hours per day), we do not expect noise-producing pile driving 
will actually occur at all times during a 24-hour period, given the 
general construction process, including time for setting up piles pile 
for installation.
    The takes from Level A and Level B harassment will be due to 
potential behavioral disturbance, TTS and PTS. No mortality or serious 
injury is anticipated given the nature of the activity. Level A 
harassment is only anticipated for ringed seal, spotted seal, and 
bearded seal. The potential for Level A harassment is minimized through 
the construction method and the implementation of the required 
mitigation measures (see Proposed Mitigation section).
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from other 
similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring) (e.g., Thorson and Reyff 
2006; HDR, Inc. 2012; Lerma 2014; ABR 2016). Most likely for pile 
driving, individuals will simply move away from the sound source and be 
temporarily displaced from the areas of pile driving, although even 
this reaction has been observed primarily only in association with 
impact pile driving, which is just a portion of AGDC's construction. 
Level B harassment will be reduced to the level of least practicable 
adverse impact through use of mitigation measures described herein. If 
sound produced by project activities is sufficiently disturbing, 
animals are likely to simply avoid the area while the activity is 
occurring. While vibratory driving associated with the project may 
produce sound at distances of many kilometers from the project site, 
the project site itself is located in an active industrial area, as 
previously described. Therefore, we expect that animals annoyed by 
project sound will simply avoid the area and use more-preferred 
habitats.
    In addition to the expected effects resulting from authorized Level 
B harassment, we anticipate that ringed seals, spotted seals, and 
bearded seals may sustain some limited Level A harassment in the form 
of auditory injury. However, animals that experience PTS will likely 
only receive slight PTS, i.e., minor degradation of hearing 
capabilities within regions of hearing that align most completely with 
the frequency range of the energy produced by pile driving, i.e., the 
low-frequency region below 2 kHz, not severe hearing impairment or 
impairment in the regions of greatest hearing sensitivity. If hearing 
impairment occurs, it is most likely that the affected animal will lose 
a few decibels in its hearing sensitivity, which in most cases is not 
likely to

[[Page 43411]]

meaningfully affect its ability to forage and communicate with 
conspecifics.
    Habitat disturbance and alteration resulting from project 
activities could have a few highly localized, short-term effects for a 
few marine mammals, however, the area of affected habitat would be 
small compared to that available to marine mammal species. The 
activities may cause some fish to leave the area of disturbance, thus 
temporarily impacting marine mammals' foraging opportunities in a 
limited portion of the foraging range. We do not expect pile driving 
activities to have significant, long-term consequences to marine 
invertebrate populations. Given the short duration of the activities 
and the relatively small area of the habitat that may be affected, the 
impacts to marine mammal habitat, including fish and invertebrates, are 
not expected to cause significant or long-term negative consequences.
    AGDC's February to April pile driving contingency period overlaps 
with the period when ringed seals are constructing subnivean lairs, 
giving birth, and nursing pups. As discussed in the Proposed Mitigation 
section, AGDC will be required to begin construction prior to March 1 
when ringed seals are known to begin constructing lairs. As such, we 
expect that ringed seals will construct their lairs away from the pile 
driving operations, therefore minimizing disturbance and avoiding any 
potential for physical injury to seals in lairs. Additionally, we 
expect that AGDC will complete the majority, if not all of the pile 
driving during the open water season, so any pile driving that did 
remain could likely be completed in the earlier portion of the 
contingency period, further reducing the potential for impacts to 
ringed seals while lairing or pupping.
    As previously described, UMEs have been declared for both gray 
whales and ice seals, however, neither UME provides cause for concern 
regarding population-level impacts to any of these stocks. For gray 
whales, the estimated abundance of the Eastern North Pacific stock is 
26,960 (Carretta et al., 2019) and the stock abundance has increased 
approximately 22 percent in comparison with 2010/2011 population levels 
(Durban et al., 2017). For bearded seals, the minimum estimated mean M/
SI (557) is well below the calculated partial PBR (8,210). This PBR is 
only a portion of that of the entire stock, as it does not include 
bearded seals that overwinter and breed in the Beaufort or Chukchi Seas 
(Muto et al., 2019). For the Alaska stock of ringed seals and the 
Alaska stock of spotted seals, the M/SI (863 and 329, respectively) is 
well below the PBR for each stock (5,100 and 12,697, respectively) 
(Muto et al., 2019). No serious injury, or mortality is expected or 
proposed for authorization, and Level B harassment takes of gray whale 
and ice seal species, and Level A harassment takes of ice seals will be 
reduced to the level of least practicable adverse impact through the 
incorporation of the proposed mitigation measures. As such, the 
proposed Level B harassment takes of gray whales and ice seals and 
proposed Level A harassment takes of ice seals is not expected to 
exacerbate or compound upon the ongoing UMEs.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality or serious injury is anticipated or 
authorized;
     The relatively small number of Level A harassment 
exposures, for seals only, are anticipated to result only in slight PTS 
within the lower frequencies associated with pile driving;
     The area impacted by the specified activity is very small 
relative to the overall habitat ranges of all species;
     Impacts to critical behaviors such as lairing and pupping 
by ringed seals would be avoided and minimized through implementation 
of mitigation measures described above; and
     AGDC would cease pile driving and project vessels would 
transit landward of Cross Island during the Nuiqsut whaling season, 
therefore minimizing impacts to critical behavior (i.e., migration).
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

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, 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.
    The number of instances of take for each species or stock proposed 
to be taken as a result of this project is included in Table 19. Our 
analysis shows that less than one-third of the best available 
population abundance estimate of each stock could be taken by 
harassment (in fact, take of individuals is less than two percent of 
the abundance for all affected stocks). The number of animals proposed 
to be taken for each stock would be considered small relative to the 
relevant stock's abundances even if each estimated taking occurred to a 
new individual, which is an unlikely scenario.
    For beluga whale, the percentages in Table 19 conservatively assume 
that all takes of beluga whale will be accrued to each stock, however, 
we expect that most, if not all, beluga whales taken by this project 
will be from the Beaufort Sea stock.
    For the Alaska stock of bearded seals, a complete stock abundance 
value is not available. As noted in the 2019 Draft Alaska SAR (Muto et 
al., 2019), an abundance estimate is currently only available for the 
portion of bearded seals in the Bering Sea (Conn et al., 2012). The 
current abundance estimate for the Bering Sea is 301,836 bearded seals. 
Given the proposed 300 Level B harassment takes and 5 Level A 
harassment takes for the stock, comparison to the Bering Sea estimate, 
which is only a portion of the Alaska Stock (which also includes 
animals in the Chukchi and Beaufort Seas), shows that, at most, less 
than one percent of the stock is expected to be impacted.
    A complete stock abundance value is also not available for the 
Alaska stock of ringed seals. As noted in the 2019 Draft Alaska SAR 
(Muto et al., 2019), the abundance estimate available, 171,418 animals, 
is only a partial estimate of the Bering Sea portion of the population 
(Conn et al., 2014). As noted in the SAR, this estimate does not 
include animals in the shore fast ice zone, and the authors did not 
account for availability bias. Muto et al. (2019) expect that the 
Bering Sea portion of the population is actually much higher. Given the 
proposed 1,765 Level B harassment takes and 32 Level A harassment takes 
for the stock, comparison to the Bering Sea partial estimate, which is 
only a

[[Page 43412]]

portion of the Alaska Stock (also includes animals in the Chukchi and 
Beaufort Seas), shows that, at most, less than two percent of the stock 
is expected to be impacted.
    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.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    Project activities could deter target species from Prudhoe Bay and 
the area ensonified above the relevant harassment thresholds. However, 
as noted in the Effects of Specified Activities on Subsistence Uses of 
Marine Mammals section, subsistence use of seals is extremely limited 
in this area, as it is not within the preferred and frequented hunting 
areas. Bowhead whales typically remain outside of the area between the 
barrier islands and Prudhoe Bay, minimizing the likelihood of impacts 
from AGDC's project. Additionally, AGDC will cease pile driving 
activities during the Nuiqsut whaling season and will continue to 
coordinate with local communities and subsistence groups to minimize 
impacts of the project. AGDC will also be required to abide by the POC.
    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 AGDC's 
proposed activities.

Endangered Species Act (ESA)

    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 
Office.
    NMFS is proposing to authorize take of bowhead whale, bearded seal 
(Beringia DPS) and ringed seal (Arctic subspecies), which are listed 
under the ESA. The NMFS Alaska Regional Office issued a Biological 
Opinion under section 7 of the ESA, on the issuance of an IHA to AGDC 
under section 101(a)(5)(D) of the MMPA by the NMFS Office of Protected 
Resources. The Biological Opinion concluded that the action is not 
likely to jeopardize the continued existence of any of these species.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to AGDC for conducting construction of the Alaska LNG 
Project in Prudhoe Bay, Alaska from July 1, 2022 to June 30, 2023, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. A draft of the proposed IHA can be found 
at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed 
project. 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, or nearly identical, activities as described in the 
Specified Activities section of this notice is planned or (2) the 
activities as described in the Specified Activities section of this 
notice would not be completed by the time the IHA expires and a Renewal 
would allow for completion of the activities beyond that described in 
the Dates and Duration section of this notice, provided all of the 
following conditions are met:
     A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that the 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA).
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take); 
and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for Renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: July 13, 2020.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2020-15389 Filed 7-15-20; 8:45 am]
BILLING CODE 3510-22-P