Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Relocation of the Port of Alaska's South Floating Dock, Anchorage, Alaska, 31870-31901 [2021-12551]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 86, Number 113 (Tuesday, June 15, 2021)]
[Notices]
[Pages 31870-31901]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-12551]



[[Page 31869]]

Vol. 86

Tuesday,

No. 113

June 15, 2021

Part III





Department of Commerce





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 National Oceanic and Atmospheric Administration





Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to the Relocation of the Port of Alaska's 
South Floating Dock, Anchorage, Alaska; Notice

Federal Register / Vol. 86 , No. 113 / Tuesday, June 15, 2021 / 
Notices

[[Page 31870]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XA660]


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Relocation of the Port of 
Alaska's South Floating Dock, Anchorage, 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 Port of Alaska (POA) for 
authorization to take marine mammals incidental to pile driving 
associated with the relocation of the POA's South Floating Dock (SFD) 
in Knik Arm, 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-time, one-year renewal that could be issued 
under certain circumstances and if all requirements are met, as 
described in Request for Public Comments at the end of this notice. 
NMFS will consider public comments prior to making any final decision 
on the issuance of the requested MMPA authorizations and agency 
responses will be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than July 15, 
2021.

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 submitted 
via email to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments, including all attachments, must 
not exceed a 25-megabyte file size. All comments received are a part of 
the public record and will generally be posted online at 
www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Reny Tyson Moore, 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 IHA) 
with respect to potential impacts on the human environment.
    Accordingly, NMFS is preparing an Environmental Assessment (EA) to 
consider the environmental impacts associated with the issuance of the 
proposed IHA. NMFS' EA will be made available at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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 October 2, 2020, NMFS received a request from the POA for an IHA 
to take marine mammals incidental to pile driving associated with the 
relocation of the SFD in Knik Arm, Alaska. Revised applications were 
submitted by POA on December 15, 2020, January 29, 2021, February 5, 
2021, and March 5, 2021 that addressed comments provided by NMFS. The 
application was deemed adequate and complete on March 17, 2021. 
Additional revised applications were submitted on March 26, 2021 and 
May 14, 2021. The POA's request is for take of a small number of six 
species of marine mammals by Level B harassment and Level A harassment. 
Neither the POA nor NMFS expects serious injury or mortality to result 
from this activity and, therefore, an IHA is appropriate.
    NMFS previously issued IHAs to the POA for pile driving (73 FR 
41318, July 18, 2008; 74 FR 35136, July 20, 2009; 81 FR 15048, March 
21, 2016; and 85 FR 19294, April 06, 2020). The POA has complied with 
the requirements (e.g., mitigation, monitoring, and reporting) of all 
previous IHAs and information regarding their monitoring results may be 
found in the Effects of the Specified Activity on Marine Mammals and 
their Habitat and Estimated Take sections.

Description of Proposed Activity

Overview

    The POA is modernizing its marine terminals through the Port of 
Alaska Modernization Program (PAMP). One of the first priorities of the 
PAMP is to replace the existing Petroleum Oil Lubricants Terminal with 
a new Petroleum Cement Terminal (PCT). Phase 1 of the PCT project is 
complete, but for Phase 2 of the project to advance, the existing SFD, 
a small multipurpose floating dock constructed in 2004, must be 
relocated south of the PCT near the southern portion of the South 
Backlands Stabilization project. The existing location of SFD will not 
allow docking

[[Page 31871]]

operations at SFD once the PCT is constructed due to the close 
proximity of one of the PCT mooring dolphins (a structure for berthing 
and mooring of vessels). Therefore, it must be relocated.
    Relocation of the SFD will include the removal of the existing 
structure, including the access trestle and gangway, and installation 
of twelve permanent 36-inch steel pipe piles: Ten vertical and two 
battered. Construction of the SFD will also require the installation 
and vibratory removal of up to six 24- or 36-inch template piles. All 
pile installation will take place from a floating work barge and crane 
with a vibratory hammer to the greatest extent possible. An impact 
hammer may be used if a pile encounters refusal and cannot be advanced 
to the necessary tip elevation with the vibratory hammer. An unconfined 
bubble curtain system will be used to reduce in-water noise levels for 
the installation of the sixteen vertical piles and removal of the six 
temporary piles but will not be used during installation of the two 
battered piles due to the angle of these piles.

Dates and Duration

    The POA has requested that the IHA be valid for one year upon 
issuance. In-water pile installation and removal associated with SFD 
removal and construction is anticipated to take place on up to 24 
nonconsecutive days between the date of issuance and November 2021. 
Installation of permanent and temporary piles is anticipated to take 45 
minutes per pile with 1-3 piles being installed per day over 7-18 days. 
Removal of six temporary piles is anticipated to take 75 minutes per 
pile with 1-3 piles being removed per day over 2-6 days. All pile-
driving will occur during daylight hours.

Specific Geographic Region

    Cook Inlet is a large tidal estuary that exchanges waters at its 
mouth with the Gulf of Alaska. The inlet is roughly 20,000 square 
kilometers (km\2\; 7,700 square miles (mi\2\)) in area, with 
approximately 1,350 linear km (840 mi) of coastline (Rugh et al., 2000) 
and an average depth of approximately 100 meters (m) (330 feet (ft)). 
Cook Inlet is generally divided into upper and lower regions by the 
East and West Forelands. Freshwater input to Cook Inlet comes from 
snowmelt and rivers, many of which are glacially fed and carry high 
sediment loads. Currents throughout Cook Inlet are strong and tidally 
periodic, with average velocities ranging from three to six knots 
(Sharma and Burrell, 1970). Extensive tidal mudflats occur throughout 
Cook Inlet, especially in the upper reaches, and are exposed at low 
tides.
    Cook Inlet is a seismically active region susceptible to 
earthquakes and has some of the highest tides in North America (NOAA, 
2015) that drive surface circulation. Tides in Cook Inlet are 
semidiurnal, with two unequal high and low tides per tidal day (tidal 
day = 24 hours, 50 minutes). Due to Knik Arm's predominantly shallow 
depths and narrow widths, tides near Anchorage are greater than those 
in the main body of Cook Inlet. The tides at the POA have a mean range 
of about 8.0 m (26 ft), and the maximum water level has been measured 
at more than 12.5 m (41 ft) at the Anchorage station (NOAA, 2015). 
Maximum current speeds in Knik Arm, observed during spring ebb tide, 
exceed 7 knots (12 feet/second). These tides result in strong currents 
in alternating directions through Knik Arm and a well-mixed water 
column. Cook Inlet contains substantial quantities of mineral 
resources, including coal, oil, and natural gas. During winter, sea, 
beach, and river ice are dominant physical forces within Cook Inlet. In 
upper Cook Inlet, sea ice generally forms in October to November and 
continues to develop through February or March (Moore et al., 2000).
    Northern Cook Inlet bifurcates into Knik Arm to the north and 
Turnagain Arm to the east. The POA is located in the southeastern 
shoreline of Knik Arm in Anchorage, Alaska (Latitude 61[deg]15' N, 
Longitude 149[deg]52' W; Seward Meridian) (Figure 1). Knik Arm is 
generally considered to begin at Point Woronzof, 7.4 km (4.6 mi) 
southwest of the POA. From Point Woronzof, Knik Arm extends about 48 km 
(30 mi) in a north-northeasterly direction to the mouths of the 
Matanuska and Knik rivers. At Cairn Point, just northeast of the POA, 
Knik Arm narrows to about 2.4 km (1.5 mi) before widening to as much as 
8 km (5 mi) at the tidal flats northwest of Eagle Bay at the mouth of 
Eagle River, which are heavily utilized by Cook Inlet Beluga Whales 
(CIBWs). Approximately 60 percent of Knik Arm is exposed at mean lower 
low water (MLLW). The intertidal (tidally influenced) areas of Knik 
Arm, including those at the POA, are mudflats, both vegetated and 
unvegetated, which consist primarily of fine, silt-sized glacial flour.
    The POA's boundaries currently occupy an area of approximately 129 
acres. Other commercial and industrial activities related to secure 
maritime operations are located near the POA on Alaska Railroad 
Corporation (ARRC) property immediately south of the POA, on 
approximately 111 acres. The PCT footprint spans approximately 0.87 
acre and is approximately 0.74 km (0.46 m) north of Ship Creek, a 
location of concentrated marine mammal activity during seasonal runs of 
several salmon species. Ship Creek flows into Knik Arm through the 
Municipality of Anchorage industrial area. The perpendicular distance 
to the west bank directly across Knik Arm from the POA is approximately 
4.2 km (2.6 mi).
BILLING CODE 3510-22-P

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[GRAPHIC] [TIFF OMITTED] TN15JN21.013

BILLING CODE 3510-22-C

Detailed Description of Specific Activity

    Located within the Municipality of Anchorage on Knik Arm in upper 
Cook Inlet, the POA (Figure 1) provides critical infrastructure for the 
citizens of Anchorage and a majority of the citizens of Alaska. The 
POA's existing infrastructure and support facilities were constructed 
largely in the 1960s. Port facilities are substantially past their 
design life, have degraded to levels of

[[Page 31873]]

marginal safety, and are in many cases functionally obsolete, 
especially in regard to seismic design criteria and condition. To 
address these deficiencies, the POA is modernizing its marine terminals 
through the PAMP. Plans for modernization include replacing 
deteriorated pile-supported infrastructure with new pile-supported 
infrastructure. One of the first priorities of the PAMP is to replace 
the existing Petroleum Oil Lubricants Terminal with a new structure 
that exceeds current seismic standards. For the new PCT Project to 
advance, the existing SFD, a small multipurpose floating dock 
constructed in 2004, must be relocated south of the PCT near the 
southern portion of the South Backlands Stabilization project (Figure 
1). The existing location of SFD will not allow docking operations at 
SFD once the PCT is constructed due to close proximity of one of the 
PCT mooring dolphins.
    The purpose of the SFD is to provide staging, mooring, and docking 
of small vessels, such as first responder (e.g., Anchorage Fire 
Department, U.S. Coast Guard) rescue craft, small work skiffs, and 
occasionally tug boats, in an area close to the daily operations at the 
Port. Upper Cook Inlet near Anchorage exhibits the largest tide range 
in the United States and one of the largest tide ranges in the world, 
with an average daily difference between high and low tide of 26.2 feet 
and an extreme difference of up to 41 feet (NOAA, 2015). The ability of 
first responders to conduct response operations during low tide stages 
requires access to the SFD, as the waterline is inaccessible for 
vessels at the Anchorage public boat launch at Ship Creek during low 
tide stages. The planned relocation of the SFD south of the new PCT 
structure will provide continuous access to the water, and relocation 
is needed to continue to provide timely, safe access for rescue 
personnel and vessels in the northern portion of Cook Inlet.
    Relocation of the SFD will include the removal of the existing 
structure, including the float and gangway, and installation of twelve 
permanent 36-inch steel piles: Four for the gangway and eight for the 
floating dock (Table 1). Ten of the permanent piles will be plumb 
(i.e., vertical) piles; but two of these piles, located at the south 
corner of the floating dock, will be battered piles due to lateral ice 
flow conditions. Two of the permanent 36-inch gangway piles at Bent B, 
the bent closest to shore, may be installed when the area is de-
watered, but will likely be installed in water. Temporary template 
piles may be required to assist with permanent pile placement and would 
consist of up to six 24- or 36-inch steel pipe piles (Table 1): 4 For 
the gangway and 2 for the float. To allow for flexibility in design, 
temporary piles may be all of one size or a combination of 24- and 36-
inch steel pipe piles. The piles from the existing SFD piles will be 
left in place and will not be removed.
    All piles will be installed with a vibratory hammer to the greatest 
extent possible, with each pile requiring approximately 45 minutes to 
install (Table 1), based on an analysis of PCT Phase 1 data. An impact 
hammer may be required if a pile encounters refusal and cannot be 
advanced to the necessary tip elevation with the vibratory hammer. 
Refusal criteria for a vibratory hammer is defined by the hammer 
manufacturer and is described as the pile not advancing one foot within 
30 seconds of vibratory hammer operation at full speed. Three piles 
have deeper embedment depth than others and may reach refusal before 
the specified minimum tip elevation. In such a situation, an impact 
hammer would be needed to drive these piles to their required depth. A 
small number of total piles, estimated up to five piles, may reach 
refusal before the tip elevation is reached, requiring up to 20 minutes 
of impact installation each at one pile per day. POA estimates that 
each of these piles could require up to 1,000 strikes, which was the 
mean number of strikes measured for 48-inch production piles during the 
PCT Phase 1 construction sound source verification (SSV) study (Reyff 
et al., 2021). It is likely that the number of strikes will be less due 
to the smaller pile sizes associated with SFD. To be conservative, 
1,000 strikes were used to calculate Level A harassment zone sizes. It 
is assumed that if a pile does require impact installation, the 
vibratory installation time would be reduced by a commensurate amount 
(i.e., 15 minutes of impact installation would replace 15 minutes of 
vibratory installation), and the overall duration of installation would 
remain the same.
    Temporary template piles (n = 6) will be removed with a vibratory 
hammer (Table 1). Based on an analysis of PCT Phase 1 data, each 
temporary pile will require approximately 75 minutes of vibratory 
hammer removal. Knik Arm soils have demonstrated a strong set up and 
resistance condition on temporary piles due to dense clay composition, 
making removal lengthier and more difficult than installation. The 
temporary piles for the SFD will be in place for only approximately 
three weeks and will not be load-bearing, in contrast to the piles used 
for the PCT temporary trestle that were in place for approximately five 
months and subject to loads from the construction crane. The temporary 
SFD piles will likely require less time for removal than PCT piles at 
approximately two-thirds duration. Based on this, the estimated removal 
time is approximately two-thirds of the duration required for vibratory 
removal of 36-inch temporary trestle piles during PCT Phase 1 
construction. All of the existing SFD float and gangway piles will 
remain in place; a vibratory hammer will not be required for their 
removal.

                                                      Table 1--Pile Details and Estimated Effort Required for Pile Installation and Removal
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                                                                                                                            Potential   Production rate (piles/day)
                                                                                                                              impact   -----------------------------
                                                                                      Vibratory                            strikes per
                                                        Number of    Number of       installation      Vibratory removal     pile, if                                    Days of       Days of
       Pipe pile diameter               Feature        plumb piles    battered    duration per pile    duration per pile    needed (up                                installation     removal
                                                                       piles          (minutes)            (minutes)       to 5 piles;   Installation     Removal
                                                                                                                             one pile
                                                                                                                             per day)
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36-inch.........................  Floating Dock......            6            2  45.................  n/a................        1,000             1-3          n/a            4-12          n/a
                                  Gangway............            4            0                       n/a................        1,000             1-3          n/a                          n/a
24- or 36-inch..................  Temporary Template             6            0  45.................  75.................        1,000             1-2          1-3             3-6          2-6
                                   Piles.
                                                      ------------------------------------------------------------------------------------------------------------------------------------------
                    Project Totals                              16            2  13.5 hours.........  7.5 hours..........  ...........  ..............  ...........            7-18          2-6
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    The POA will use an unconfined bubble curtain noise attenuation 
system to mitigate noise propagation during vibratory installation and 
potential impact installation of the ten permanent plumb piles and six 
temporary plumb piles and vibratory removal of the six temporary piles 
when water depth is deep enough to deploy a bubble curtain 
(approximately 3 m). Pile installation or removal in the dry, which is 
a completely de-watered state, is unlikely but, if it occurs, will be 
conducted without a bubble curtain. A bubble curtain will not be used 
with the two battered piles due to the angle of installation. Use of an 
unconfined bubble curtain is proposed instead of a confined bubble 
curtain in order to reduce the need for additional template piles that 
would be required to stabilize a confined bubble curtain.
    All pile installation will take place from a floating work barge 
and crane. A marine-based operation is required because of the extreme 
tidal range, which precludes use of a land-based crane in the absence 
of a temporary support trestle. The floating work barge will require 
sufficient water depth for support. Opportunities to install piles when 
the project site is dewatered will be limited. Piles will be installed 
in water and multiple piles will likely not be driven concurrently.
    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

    There are six species of marine mammals that may be found in upper 
Cook Inlet during the proposed pile driving activities. Sections 3 and 
4 of the POA's 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' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments), and 
more general information about these species (e.g., physical and 
behavioral descriptions) may be found on NMFS's website (https://www.fisheries.noaa.gov/find-species). Additional information on CIBWs 
may be found in NMFS' 2016 Recovery Plan for the CIBW (Delphinapterus 
leucas), available online at https://www.fisheries.noaa.gov/resource/document/recovery-plan-cook-inlet-beluga-whale-delphinapterus-leucas.
    Table 2 lists all species or stocks for which take is expected and 
proposed to be authorized for this action and summarizes information 
related to the population or stock, including regulatory status under 
the MMPA and Endangered Species Act (ESA) and potential biological 
removal (PBR), where known. For taxonomy, we follow Committee on 
Taxonomy (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' U.S. 2019 SARs (e.g., Muto et al., 2020a) and 2020 draft SARs 
(Muto et al., 2020b). All values presented in Table 2 are the most 
recent available at the time of publication and are available in the 
2019 SARs (Muto et al., 2020a) and 2020 draft SARs (Muto et al., 2020b) 
(available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                                    Table 2--Marine Mammal Species Potentially Occurring in Upper Cook Inlet, Alaska
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                                                                                         ESA/MMPA status;    Stock  abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenopteridae (rorquals):
    Humpback whale..................  Megaptera novaeangliae.  Western North Pacific..  E/D; Y              1,107 (0.3, 865, 2006)          3        2.8
                                                               Central North Pacific..  -/-; Y              10,103 (0.3, 7890,             83         26
                                                                                                             2006).
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                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
    Beluga whale....................  Delphinapterus leucas..  Cook Inlet.............  E/D; Y              279 (0.06, 267, 2018).       0.53          0
    Killer whale....................  Orcinus orca...........  Alaska Resident........  -/-; N              2,347 (N/A, 1102,347,          24          1
                                                                                                             2012).
                                                               Alaska Transient.......  -/-; N              587 (N/A, 587, 2012)..       5.87        0.8
Family Phocoenidae (porpoises):
    Harbor porpoise.................  Phocoena...............  Gulf of Alaska.........  -/-; Y              31,046 (0.214, N/A,         Undet         72
                                                                                                             1998).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion................  Eumetopias jubatus.....  Western................  E/D; Y              53,932 (N/A, 52,932           318        255
                                                                                                             2013).
Family Phocidae (earless seals):

[[Page 31875]]

 
    Harbor seal.....................  Phoca vitulina.........  Cook Inlet/Shelikof....  -/-; N              28,411 (N/A, 26,907,          807        107
                                                                                                             2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable because it has not been calculated.
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
  fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated
  with estimated mortality due to commercial fisheries is presented in some cases.

    As indicated above, all six species (with six managed stocks) in 
Table 2 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur, and we have proposed 
authorizing it. Marine mammals occurring in Cook Inlet that are not 
expected to be observed in the project area and for which take is not 
proposed include gray whales (Eschrichtius robustus), minke whales 
(Balaenoptera acutorostrata), and Dall's porpoise (Phocoenoides dalli). 
Data from the Alaska Marine Mammal Stranding Network database (NMFS, 
unpublished data) provide additional support for the determination that 
these species rarely occur in upper Cook Inlet. Since 2011, only one 
minke whale and one Dall's porpoise have been documented as stranded in 
the portion of Cook Inlet north of Point Possession. Both were dead 
upon discovery; it is unknown if they were alive upon their entry into 
upper Cook Inlet or drifted into the area with the tides. No gray 
whales were reported as stranded in upper Cook Inlet during this time 
period; however, one juvenile gray whale was observed on May 24, 2020 
during PCT Phase 1 construction monitoring (61 North Environmental, 
2021). This whale was first observed mid-inlet off Port MacKenzie then 
travelled along the southeastern shore of Knik Arm until it was last 
sighted near Point Woronzof. On May 27, 2020, there were reports that a 
juvenile gray whale, believed to be the same whale, was stranded in the 
Twentymile River, at the eastern end of Turnagain Arm, approximately 50 
mi southeast of Knik Arm. The animal remained in the river for a week, 
before swimming out of the river. The whale later stranded and died 
about 25 mi away at the mouth of the Theodore River on June 12, 2020. 
No in water pile installation occurred on 23 to 25 May, and there is no 
indication that work at the PCT had any effect on the animal. Based on 
photos and video NMFS collected of the whale, veterinarians determined 
the whale was in fair to poor condition (see https://www.fisheries.noaa.gov/feature-story/alaska-gray-whale-ume-update-twentymile-river-whale-likely-one-twelve-dead-gray-whales for more 
information). With very few exceptions, minke whales, gray whales, and 
Dall's porpoises do not occur in upper Cook Inlet; and, therefore, take 
of these species is not requested in this application.
    In addition, sea otters (Enhydra lutris) may be found in Cook 
Inlet. However, sea otters are managed by the U.S. Fish and Wildlife 
Service (USFWS) and are not considered further in this document.

Humpback Whale

    Currently, three stocks of humpback whales are recognized in the 
North Pacific, migrating between their respective summer/fall feeding 
areas and winter/spring calving and mating areas (Baker et al., 1998; 
Calambokidis et al., 1997): (1) The California/Oregon/Washington and 
Mexico stock, (2) the Central North Pacific stock, and (3) the Western 
North Pacific stock. Humpback whales from the Western North Pacific 
breeding stock overlap broadly on summer feeding grounds with whales 
from the Central North Pacific breeding stock, as well as with whales 
that winter in the Revillagigedo Islands in Mexico (Muto et al., 2020a, 
2020b). Despite this overlap, the whales seasonally found in Cook Inlet 
are probably of the Central North Pacific stock (Muto et al., 2020a, 
2020b). The Central North Pacific stock winters in Hawaii (Baker et 
al., 1986) and summers from British Columbia to the Aleutian Islands 
(Calambokidis et al., 1997), including Cook Inlet.
    The humpback whale ESA listing final rule (81 FR 62259, September 
8, 2016) delineated 14 Distinct Population Segments (DPSs) with 
different listing statuses. The most comprehensive photo-identification 
data available suggest that approximately 89 percent of all humpback 
whales in the Gulf of Alaska are members of the Hawaii DPS, 11 percent 
are from the Mexico DPS, and less than 1 percent are from the western 
North Pacific DPS (Wade et al., 2016). The Hawaii DPS is not listed 
under the ESA, the Mexico DPS is listed as threatened, and the Western 
North Pacific DPS is listed as endangered under the ESA. Members of 
different DPSs are known to intermix in feeding grounds; therefore, all 
waters off the coast of Alaska should be considered to have ESA-listed 
humpback whales. NMFS is in the process of reviewing humpback whale 
stock structure under the MMPA in light of the 14 DPSs established 
under the ESA.
    Humpback whales are encountered regularly in lower Cook Inlet and 
occasionally in mid-Cook Inlet; however, sightings are rare in upper 
Cook Inlet (e.g., Witteveen et al., 2011). There have been few 
sightings of humpback whales near the project area. Humpback whales 
were not documented during POA construction or scientific monitoring 
from 2005 to 2011 or during 2016 (Cornick and Pinney, 2011; Cornick and 
Saxon-Kendall, 2008, 2009; Cornick and Seagars, 2016; Cornick et al., 
2010, 2011; ICRC, 2009, 2010a, 2011a, 2012; Markowitz and McGuire, 
2007; Prevel-Ramos et al., 2006). Observers monitoring the Ship Creek 
Small Boat Launch from August 23 to September 11, 2017, recorded two 
sightings, each of a single humpback whale, which was presumed to be 
the same individual. One other humpback whale sighting has been 
recorded for the immediate vicinity of the project area. This event 
involved a stranded whale that was sighted near a number of locations 
in upper Cook Inlet before washing ashore at Kincaid Park in 2017; it 
is unclear as to whether the humpback whale was alive or deceased upon 
entering Cook Inlet waters. No humpbacks were observed from April-
November 2020 during Phase 1 PCT construction

[[Page 31876]]

monitoring (61 North Environmental, 2021).
    The Central North Pacific stock is the focus of a large whale-
watching industry in its wintering grounds (Hawaii) and summering 
grounds (Alaska). The growth of the whale-watching industry is an 
ongoing concern as preferred habitats may be abandoned if disturbance 
levels are too high (Muto et al., 2020a, 2020b). Other potential 
impacts include elevated levels of sound from anthropogenic sources 
(e.g., shipping, military sonars), harmful algal blooms (Geraci et al., 
1989), possible changes in prey distribution with climate change, 
entanglement in fishing gear, ship strikes due to increased vessel 
traffic (e.g., from increased shipping in higher latitudes and through 
the Bering Sea with changes in sea-ice coverage), and oil and gas 
activities. An intentional unauthorized take of a humpback whale by 
Alaska Natives in Toksook Bay was documented in 2016 (Muto et al., 
2020a, 2020b); however, no subsistence use of humpback whales occurs in 
Cook Inlet.
    Humpback whale populations were considerably reduced as a result of 
intensive commercial exploitation during the 20th century. Currently, 
the overall trend for most humpback whale populations found in U. S. 
waters is positive and points toward recovery (81 FR 62259; September 
8, 2016); however, this may not be uniform for all breeding areas. A 
sharp decline in observed reproduction and encounter rates of humpback 
whales from the Central North Pacific stock between 2013 and 2018 has 
been related to oceanographic anomalies and consequent impacts on prey 
resources (Cartwright et al., 2019), suggesting that humpback whales 
are vulnerable to major environmental changes.

Beluga Whale

    The CIBW stock is a small, geographically isolated population 
separated from other beluga whale populations by the Alaska Peninsula. 
The population is genetically distinct from other Alaska populations, 
suggesting the peninsula is an effective barrier to genetic exchange 
(O'Corry-Crowe et al., 1997). The CIBW population is estimated to have 
declined from 1,300 animals in the 1970s (Calkins, 1989) to about 340 
animals in 2014 (Shelden et al., 2015), and to 279 animals in 2018 
(Wade et al., 2019). The precipitous decline documented in the mid-
1990s was attributed to unsustainable subsistence practices by Alaska 
Native hunters (harvest of >50 whales per year) (Mahoney and Shelden, 
2000). Harvesting of CIBWs has not occurred since 2008 (NMFS, 2008).
    Despite protection from hunting and other threats, this stock has 
not rebounded and continues to decline (Wade et al., 2019, Muto et al., 
2020b). The population was declining at the end of the period of 
unregulated harvest, with the relatively steep decline ending in 1999, 
coincident with harvest removals dropping from an estimated 42 in 1998 
to just 0 to 2 whales per year in 2000 to 2006 (and with no removals 
after 2006). From 1999 to 2016, the rate of decline of the population 
was estimated to be 0.4 percent (SE = 0.6 percent) per year, with a 73 
percent probability of a population decline. This rate increased from 
2006 to 2016 to 0.5 percent per year, (with a 70 percent probability of 
a population decline) (Shelden et al., 2017). The latest estimates 
suggest that this rate has further increased to 2.3 percent decline per 
year from 2008 to 2018, with a 99.7 percent probability of population 
decline in the future (Wade et al., 2019, Muto et al., 2020b). No 
human-caused mortality or serious injury of CIBWs has been recently 
documented.
    The current best abundance estimate of the CIBW population from the 
aerial survey data is 279 (95 percent probability interval 250 to 317). 
This is based on the estimate of smoothed abundance for 2018, as 
described in Sheldon and Wade (2019). A comparison of the population 
estimates over time is presented in Figure 2. While Sheldon and Wade 
(2019) provides explanations for the differences between model results, 
including inadequacies and biases, the authors do not postulate on the 
reason for population decline in general (which was evident using both 
models); however, recent literature suggests prey reductions may be a 
critical contributing factor (Norman et al., 2019). This is not 
unexpected as reduced prey availability has been directly linked to 
increased mortality and reduced health and survival of other marine 
mammals populations such as the Southern Resident killer whale (e.g., 
Ward et al., 2009, Wasser et al., 2017) and California sea lion (e.g., 
McClatchie et al., 2016). The CIBW stock was designated as depleted 
under the MMPA in 2000 (65 FR 34590; May 21, 2000) and listed as 
endangered under the ESA in 2008 (73 FR 62919; October 22, 2008). 
Therefore, the CIBW stock is considered a strategic stock.

[[Page 31877]]

[GRAPHIC] [TIFF OMITTED] TN15JN21.014

    Mortality related to live stranding events, where a CIBW group 
strands as the tide recedes, has been regularly observed in upper Cook 
Inlet. Most whales involved in a live stranding event survive, although 
some associated deaths may not be observed if the whales die later from 
live-stranding-related injuries (Vos and Shelden, 2005, Burek-
Huntington et al., 2015). Between 2014 and 2018, there were reports of 
approximately 79 CIBWs involved in three known live stranding events, 
plus one suspected live stranding event with two associated deaths 
reported (NMFS, 2016a; NMFS, unpubl. Data, Muto et al., 2020b). In 
2014, necropsy results from two whales found in Turnagain Arm suggested 
that a live stranding event contributed to their deaths as both had 
aspirated mud and water. No live stranding events were reported prior 
to the discovery of these dead whales, suggesting that not all live 
stranding events are observed. A CIBW calf that stranded alive in 2017 
was sent to the Alaska SeaLife Center for rehabilitation and then 
transferred to SeaWorld in San Antonio, Texas, in 2018. Most live 
strandings occur in Knik Arm and Turnagain Arm, which are shallow and 
have large tidal ranges, strong currents, and extensive mudflats. 
Another source of CIBW mortality in Cook Inlet is predation by 
transient-type (mammal-eating) killer whales (NMFS, 2016a; Sheldon et 
al., 2003).
    In its Recovery Plan (NMFS, 2016a), NMFS identified several threats 
to CIBWs. Potential threats include: (1) High concern: Catastrophic 
events (e.g., natural disasters, spills, mass strandings), cumulative 
effects of multiple stressors, and noise; (2) medium concern: Disease 
agents (e.g., pathogens, parasites, and harmful algal blooms), habitat 
loss or degradation, reduction in prey, and unauthorized take; and (3) 
low concern: Pollution, predation, and subsistence harvest. The 
recovery plan did not treat climate change as a distinct threat but 
rather as a consideration in the threats of high and medium concern. 
Other potential threats most likely to result in direct human-caused 
mortality or serious injury of this stock include ship strikes.
    The CIBW stock remains within Cook Inlet throughout the year, 
showing only small seasonal shifts in distribution (Goetz et al., 
2012a, Lammers et al., 2013, Castallotte et al., 2015; Shelden et al., 
2015a, 2018; Lowery et al., 2019). NMFS designated two areas, 
consisting of 7,809 km\2\ (3,016 mi\2\) of marine and estuarine 
environments, considered essential for the species' survival and 
recovery as critical habitat (76 FR 20180; April 11, 2011). However, in 
recent years the range of the CIBW whale has contracted to the upper 
reaches of Cook Inlet because of the decline in the population (Rugh et 
al., 2010), and almost the entire population can be found in northern 
Cook Inlet from late spring through the summer and into the fall (Muto 
et al., 2020b). Area 1 of the CIBW critical habitat encompasses all 
marine waters of Cook Inlet north of a line connecting Point Possession 
(61.04[deg] N, 150.37[deg] W) and the mouth of Three Mile Creek 
(61.08.55[deg] N, 151.04.40[deg] W), including waters of the Susitna, 
Little Susitna, and Chickaloon Rivers below mean higher high water. 
This area provides important habitat during ice-free months and is used 
intensively by CIBWs between April and November (NMFS, 2016a). The POA, 
the adjacent navigation channel, and the turning basin were excluded 
from critical habitat designation due to national

[[Page 31878]]

security reasons (76 FR 20180; April 11, 2011). More information on 
CIBW critical habitat can be found at https://www.fisheries.noaa.gov/action/critical-habitat-cook-inlet-beluga-whale.
    Aerial surveys were conducted by NMFS each year during from 1994 to 
2012 (Rugh et al., 2000, 2005; Shelden et al., 2013, 2019) to document 
distribution and abundance of CIBWs. NMFS changed to a biennial survey 
schedule starting in 2014 after analysis showed there would be little 
reduction in the ability to detect a trend given the current growth 
rate of the population (Hobbs, 2013). The collective survey results 
show that CIBWs have been consistently found near or in river mouths 
along the northern shores of upper Cook Inlet (i.e., north of East and 
West Foreland). In particular, CIBW groups are seen in the Susitna 
River Delta, Knik Arm, and along the shores of Chickaloon Bay. Small 
groups have also been recorded farther south in Kachemak Bay, Redoubt 
Bay (Big River), and Trading Bay (McArthur River) prior to 1996 but 
very rarely thereafter. Since the mid-1990s, most (96 to 100 percent) 
CIBWs in upper Cook Inlet have been concentrated in shallow areas near 
river mouths (Sheldon et al., 2015), no longer occurring in the central 
or southern portions of Cook Inlet (Hobbs et al., 2008). Based on these 
aerial surveys, the concentration of CIBWs in the northernmost portion 
of Cook Inlet appears to be consistent from June to October (Rugh et 
al., 2000, 2004a, 2004b, 2005, 2006, 2007). Research reports generated 
from the surveys can be found at https://www.fisheries.noaa.gov/alaska/endangered-species-conservation/research-reports-and-publications-cook-inlet-beluga-whales.
    Though CIBWs can be found throughout the inlet at any time of year, 
they spend the ice-free months generally in the upper Cook Inlet, 
shifting into the middle and lower Inlet in winter (Hobbs et al., 
2005). In 1999, one CIBW was tagged with a satellite transmitter, and 
its movements were recorded from June through September of that year. 
Since 1999, 18 CIBWs in upper Cook Inlet have been captured and fitted 
with satellite tags to provide information on their movements during 
late summer, fall, winter, and spring (Goetz et al., 2012a; Shelden et 
al., 2015a, 2018). All tagged CIBWs remained in Cook Inlet (Shelden et 
al., 2015a, 2018). Most tagged whales were in the lower to middle inlet 
(70 to 100 percent of tagged whales) during January through March, near 
the Susitna River Delta from April to July (60 to 90 percent of tagged 
whales) and in the Knik and Turnagain Arms from August to December 
(Ezer et al., 2013). More recently, the Marine Mammal Lab has conducted 
long-term passive acoustic monitoring demonstrating seasonal shifts in 
CIBW concentrations throughout Cook Inlet. Castellote et al. (2015) 
conducted long-term acoustic monitoring at 13 locations throughout Cook 
Inlet between 2008 and 2015: North Eagle Bay, Eagle River Mouth, South 
Eagle Bay, Six Mile, Point MacKenzie, Cairn Point, Fire Island, Little 
Susitna, Beluga River, Trading Bay, Kenai River, Tuxedni Bay, and Homer 
Spit; the former six stations being located within Knik Arm. In 
general, the observed seasonal distribution is in accordance with 
descriptions based on aerial surveys and satellite telemetry: CIBW 
detections are higher in the upper inlet during summer, peaking at 
Little Susitna, Beluga River, and Eagle Bay, followed by fewer 
detections at those locations during winter. Higher detections in 
winter at Trading Bay, Kenai River, and Tuxedni Bay suggest a broader 
CIBW distribution in the lower inlet during winter.
    CIBWs are generally concentrated near the warmer waters of river 
mouths during the spring and summer because that is where prey 
availability is high and predator occurrence is low (Moore et al., 
2000). Goetz et al. (2012b) modeled habitat preferences using NMFS' 
1994-2008 June abundance survey data. In large areas, such as the 
Susitna Delta (Beluga to Little Susitna Rivers) and Knik Arm, there was 
a high probability that CIBWs were in larger group sizes. CIBW presence 
also increased closer to rivers with Chinook salmon (Oncorhynchus 
tshawytscha) runs, such as the Susitna River. Movement has been 
correlated with the peak discharge of seven major rivers emptying into 
Cook Inlet. Boat-based surveys from 2005 to the present (McGuire and 
Stephens, 2017) and results from passive acoustic monitoring across the 
entire inlet (Castellote et al., 2015) also support seasonal patterns 
observed with other methods. Based on long-term passive acoustic 
monitoring, seasonally, foraging behavior was more prevalent during 
summer, particularly at upper inlet rivers, than during winter. 
Foraging index was highest at Little Susitna, with a peak in July-
August and a secondary peak in May, followed by Beluga River and then 
Eagle Bay; monthly variation in the foraging index indicates CIBWs 
shift their foraging behavior among these three locations from April 
through September.
    CIBWs in Cook Inlet are believed to mostly calve between mid-May 
and mid-July, and concurrently breed between late spring and early 
summer (NMFS, 2016a), primarily in upper Cook Inlet. The only known 
observed occurrence of calving occurred on July 20, 2015, in the 
Susitna Delta area (T. McGuire, pers. comm. March 27, 2017). The first 
neonates encountered during each field season from 2005 through 2015 
were always seen in the Susitna River Delta in July. The photographic 
identification team's documentation of the dates of the first neonate 
of each year indicate that calving begins in mid-late July/early 
August, generally coinciding with the observed timing of annual maximum 
group size. Probable mating behavior of CIBWs was observed in April and 
May of 2014, in Trading Bay. Young CIBWs are nursed for two years and 
may continue to associate with their mothers for a considerable time 
thereafter (Colbeck et al., 2013).
    The POA conducted dedicated monitoring during PCT Phase 1 
construction between April and November 2020 (61 North Environmental, 
2021). In total, protected species observers (PSOs) observed 245 groups 
of approximately 987 CIBWs near the POA (group sizes ranged from 1 to 
53 individuals), with the most number of individuals and groups being 
seen in August (N = 56 groups of 274 individuals) and September (N = 73 
groups of 276 individuals). CIBWs were observed in every month of the 
project (except during October, which only included three project and 
monitoring days) with the highest sightings per unit effort, measured 
as CIBWs per hour of observation, occurring at the end of August and 
beginning of September.

Killer Whale

    Killer whales are found throughout the North Pacific Ocean. Along 
the west coast of North America, seasonal and year-round occurrence of 
killer whales occur has been noted along the entire Alaska coast 
(Braham and Dahlheim, 1982), in British Columbia and Washington inland 
waterways (Bigg et al., 1990), and along the outer coasts of 
Washington, Oregon, and California (Green et al., 1992; Barlow 1995, 
1997; Forney et al., 1995). Killer whales from these areas have been 
labeled as ``resident,'' ``transient,'' and ``offshore'' type killer 
whales (Bigg et al., 1990, Ford et al., 2000, Dahlheim et al., 2008) 
based on aspects of morphology, ecology, genetics, and behavior (Ford 
and Fisher, 1982; Baird and Stacey, 1988; Baird et al., 1992; Hoelzel 
et al., 1998, 2002; Barrett Lennard, 2000; Dahlheim et al., 2008). Two 
stocks of killer whales may be present in upper Cook Inlet: The Eastern 
North Pacific Alaska Resident stock and the Gulf of Alaska, Aleutian 
Islands, and Bering Sea

[[Page 31879]]

Transient stock. Both ecotypes overlap in the same geographic area; 
however, they maintain social and reproductive isolation and feed on 
different prey species.
    While there have been some anecdotal reports of killer whales 
feeding on CIBWs in upper Cook Inlet, sightings in this region and near 
the POA are rare (e.g., NMFS, 2016a; Sheldon et al., 2003). During 
aerial surveys conducted between 1993 and 2004 in Cook Inlet, killer 
whales were only observed on three flights, and all sightings were 
located in the Kachemak and English Bay area, south of the POA (Rugh et 
al., 2005). Acoustic monitoring carried out by Castellote et al. (2016) 
between 2008 and 2013 only detected one transient killer whale at 
Beluga River, located along the western shore of Cook Inlet, west of 
the POA. Surveys conducted by Funk et al., (2005), Ireland et al., 
(2005), Brueggeman et al., (2007, 2008a, 2008b), and McGuire et al., 
(2020) did not observe killer whales in the vicinity of or north of the 
POA. Lastly, killer whales were not observed during POA construction or 
scientific monitoring from 2005 to 2011, during the 2016 Test Pile 
Program (TPP), or during Phase 1 of the PCT project carried out between 
April-November 2020 (61 North Environmental, 2021). Therefore, very few 
killer whales, if any, are expected to approach or be near the project 
area during construction of the SFD.
    Killer whales are not harvested for subsistence in Alaska. 
Potential threats most likely to result in direct human-caused 
mortality or serious injury of killer whales in this region include oil 
spills, vessel strikes, and interactions with fisheries. Based on 
currently available data, a minimum estimate of the mean annual 
mortality and serious injury rate for both the Alaska Residents and 
Gulf of Alaska, Aleutian Islands, and Bering Sea Transient stocks due 
to U.S. commercial fisheries is less than 10 percent of the PBR and, 
therefore, is considered to be insignificant and approaching zero 
mortality and serious injury rate. Therefore, neither stock is 
classified as a strategic stock (Muto et al., 2020b).

Harbor Porpoise

    Harbor porpoises primarily frequent the coastal waters of the Gulf 
of Alaska and Southeast Alaska (Dahlheim et al., 2000, 2009), typically 
occurring in waters less than 100 m deep (Hobbs and Waite, 2010). 
Harbor porpoise prefer nearshore areas, bays, tidal areas, and river 
mouths (Dahlheim et al., 2000, 2009, 2015; Hobbs and Waite, 2010). In 
Alaskan waters, NMFS has designated three stocks of harbor porpoises 
for management purposes: Southeast Alaska, Gulf of Alaska, and Bering 
Sea Stocks (Muto et al., 2020b). Porpoises found in Cook Inlet belong 
to the Gulf of Alaska Stock, which is distributed from Cape Suckling to 
Unimak Pass.
    Although harbor porpoises have been frequently observed during 
aerial surveys in Cook Inlet (Shelden et al., 2014), most sightings are 
of single animals and are concentrated at Chinitna and Tuxedni bays on 
the west side of lower Cook Inlet (Rugh et al., 2005). The occurrence 
of larger numbers of porpoise in the lower Cook Inlet may be driven by 
greater availability of preferred prey and possibly less competition 
with CIBWs, as CIBWs move into upper inlet waters to forage on Pacific 
salmon during the summer months (Shelden et al., 2014).
    There has been an increase in harbor porpoise sightings in upper 
Cook Inlet over the past two decades (Shelden et al., 2014). Small 
numbers of harbor porpoises have been consistently reported in upper 
Cook Inlet between April and October (Prevel-Ramos et al., 2008). 
Harbor porpoises have been observed within Knik Arm during monitoring 
efforts since 2005. During POA construction from 2005 through 2011 and 
in 2016, harbor porpoises were reported in 2009, 2010, and 2011 
(Cornick and Saxon-Kendall, 2008, 2009; Cornick and Seagars, 2016; 
Cornick et al., 2010, 2011; Markowitz and McGuire, 2007; Prevel-Ramos 
et al., 2006). In 2009, 20 harbor porpoises were observed during 
construction monitoring, with sightings in June, July, August, October, 
and November. Harbor porpoises were observed twice in 2010, once in 
July and again in August. In 2011, POA monitoring efforts documented 
harbor porpoises five times, with a total of six individuals, in 
August, October, and November at the POA (Cornick et al., 2011). During 
other monitoring efforts conducted in Knik Arm, there were four 
sightings of harbor porpoises in 2005 (Shelden et al., 2014), and a 
single harbor porpoise was observed within the vicinity of the POA in 
October 2007. More recent monitoring conducted during Phase 1 PCT 
construction documented 15 groups (18 individuals) of harbor porpoises 
near the POA between April and November 2020 (group sizes ranged 1-2 
individuals) (61 North Environmental, 2021).
    Estimates of human-caused mortality and serious injury from 
stranding data and fisherman self-reports are underestimates because 
not all animals strand or are self-reported nor are all stranded 
animals found, reported, or have the cause of death determined. In 
addition, the trend of this stock is unknown given existing data is 
more than eight years old. NMFS considers this stock strategic because 
the level of mortality and serious injury would likely exceed the PBR 
level if we had accurate information on stock structure, a newer 
abundance estimate, and complete fisheries observer coverage. Given 
their shallow water distribution, harbor porpoise are vulnerable to 
physical modifications of nearshore habitats resulting from urban and 
industrial development (including waste management and nonpoint source 
runoff) and activities such as construction of docks and other over-
water structures, filling of shallow areas, dredging, and noise 
(Linnenschmidt et al., 2013). Subsistence users have not reported any 
harvest from the Gulf of Alaska harbor porpoise stock since the early 
1900s (Shelden et al., 2014).

Steller Sea Lion

    Steller sea lions inhabiting Cook Inlet belong to the Western 
distinct population segment (WDPS), and this is the stock considered in 
this analysis. NMFS defines the Steller sea lion WDPS as all 
populations west of longitude 144[deg] W to the western end of the 
Aleutian Islands. The most recent comprehensive aerial photographic and 
land-based surveys of WDPS Steller sea lions in Alaska were conducted 
during the 2018 (Aleutian Islands west of Shumagin Islands) and 2019 
(Southeast Alaska and Gulf of Alaska east of Shumagin Islands) breeding 
seasons (Sweeney et al., 2018, 2019). The WDPS of Steller sea lions is 
currently listed as endangered under the ESA (55 FR 49204, November 26, 
1990) and designated as depleted under the MMPA. NMFS designated 
critical habitat on August 27, 1993 (58 FR 45269). The critical habitat 
designation for the WDPS of Steller sea lions was determined to include 
a 37 km (20 nm) buffer around all major haul-outs and rookeries, and 
associated terrestrial, atmospheric, and aquatic zones, plus three 
large offshore foraging areas, none of which occurs in the project 
area. Steller sea lions feed largely on walleye pollock, salmon, and 
arrowtooth flounder during the summer, and walleye pollock and Pacific 
cod during the winter (Sinclair and Zeppelin, 2002). Except for salmon, 
none of these are found in abundance in upper Cook Inlet (Nemeth et 
al., 2007).
    Within Cook Inlet, Steller sea lions primarily inhabit lower Cook 
Inlet. However, they occasionally venture to upper Cook Inlet and Knik 
Arm and may be attracted to salmon runs in the region. Steller sea 
lions have been

[[Page 31880]]

observed near the POA in 2009 (ICRC 2009), 2016 (Cornick and Seagars, 
2016), and in 2020 during Phase 1 PCT construction monitoring (61 North 
Environmental, 2021). During POA construction monitoring in June of 
2009, a Steller sea lion was documented three times (within the same 
day) in Knik Arm and was believed to be the same individual (ICRC, 
2009). In 2016, Steller sea lions were observed on two separate days. 
On May 2, 2016, one individual was sighted. On May 25, 2016, there were 
five Steller sea lion sightings within a 50-minute period, and these 
sightings occurred in areas relatively close to one another suggesting 
they were likely the same animal (Cornick and Seagars, 2016). Most 
recently, up to six Steller sea lions were sighted across four days 
between May 29 and June 24, 2020 during Phase PCT 1 construction 
monitoring (61 North Environmental, 2021). At least two of these 
sightings may have been re-sights on the same individual. An additional 
seven unidentified pinnipeds were observed that could have been Steller 
sea lions or harbor seals (61 North Environmental, 2021).
    The minimum estimated mean annual level of human-caused mortality 
and serious injury for Western U.S. Steller sea lions between 2014 and 
2018 is 255 sea lions: 38 in U.S. commercial fisheries, 0.8 in unknown 
(commercial, recreational, or subsistence) fisheries, 3.2 in marine 
debris, 3.6 due to other causes (arrow strike, entangled in hatchery 
net, illegal shooting, mortality incidental to Marine Mammal Protection 
Act (MMPA) authorized research), and 209 in the Alaska Native 
subsistence harvest (Muto et al., 2020b). However, there are multiple 
nearshore commercial fisheries which are not observed; thus, there is 
likely to be unreported fishery-related mortality and serious injury of 
Steller sea lions.
    Several factors may have been important drivers of the decline of 
the stock. However, there is uncertainty about threats currently 
impeding their recovery, particularly in the Aleutian Islands. Many 
factors have been suggested as causes of the steep decline in abundance 
of western Steller sea lions observed in the 1980s, including 
competitive effects of fishing, environmental change, disease, 
contaminants, killer whale predation, incidental take, and illegal and 
legal shooting (Atkinson et al., 2008; NMFS, 2008a). A number of 
management actions have been implemented since 1990 to promote the 
recovery of the Western U.S. stock of Steller sea lions, including 3-
nmi no-entry zones around rookeries, prohibition of shooting at or near 
sea lions, and regulation of fisheries for sea lion prey species (e.g., 
walleye pollock, Pacific cod, and Atka mackerel) (Sinclair et al., 
2013, Tollit et al., 2017). Additionally, potentially deleterious 
events, such as harmful algal blooms (Lefebvre et al., 2016) and 
disease transmission across the Arctic (VanWormer et al., 2019) that 
have been associated with warming waters, could lead to potentially 
negative population-level impacts on Steller sea lions.

Harbor Seal

    Harbor seals inhabit coastal and estuarine waters off Baja 
California, north along the western coasts of the United States, 
British Columbia, and Southeast Alaska, west through the Gulf of Alaska 
and Aleutian Islands, and in the Bering Sea north to Cape Newenham and 
the Pribilof Islands. They haul out on rocks, reefs, beaches, and 
drifting glacial ice and feed in marine, estuarine, and occasionally 
fresh waters. Harbor seals generally are non-migratory, with local 
movements associated with such factors as tides, weather, season, food 
availability, and reproduction (Scheffer and Slipp, 1944; Fisher, 1952; 
Bigg, 1969, 1981; Hastings et al., 2004). NMFS currently identifies 
twelve stocks of harbor seals based largely on genetic structure (Muto 
et al., 2020a). Harbor seals from the Cook Inlet/Shelikof Strait stock, 
which ranges from the southwest tip of Unimak Island east along the 
southern coast of the Alaska Peninsula to Elizabeth Island off the 
southwest tip of the Kenai Peninsula, including Cook Inlet, Knik Arm, 
and Turnagain Arm, are considered in this analysis.
    Harbor seals belonging to this stock inhabit the coastal and 
estuarine waters of Cook Inlet and are observed in both upper and lower 
Cook Inlet throughout most of the year (Boveng et al., 2012; Shelden et 
al., 2013). Research on satellite-tagged harbor seals conducted between 
2004 and 2006 observed several movement patterns within Cook Inlet 
(Boveng et al., 2012), including a strong seasonal pattern of more 
coastal and restricted spatial use during the spring and summer 
(breeding, pupping, molting) and more wide-ranging movements within and 
outside of Cook Inlet during the winter months, with some seals ranging 
as far as Shumigan Islands. During summer months, movements and 
distribution was mostly confined to the west side of Cook Inlet and 
Kachemak Bay, and seals captured in lower Cook Inlet generally 
exhibited site fidelity by remaining south of the Forelands in lower 
Cook Inlet after release (Boveng et al., 2012).
    The presence of harbor seals in upper Cook Inlet is seasonal. 
Harbor seals are commonly observed along the Susitna River and other 
tributaries within upper Cook Inlet during eulachon and salmon 
migrations (NMFS, 2003). The major haulout sites for harbor seals are 
located in lower Cook Inlet with fewer sites in upper Cook Inlet 
(Montgomery et al., 2007). In the project area (Knik Arm), harbor seals 
tend to congregate near the mouth of Ship Creek (Cornick et al., 2011; 
Shelden et al., 2013), likely foraging on salmon and eulachon runs. 
Approximately 138 harbor seals were observed during POA monitoring 
prior to 2020, with sightings ranging from three individuals in 2008 to 
59 individuals in 2011. During 2020 PCT Phase 1 construction 
monitoring, harbor seals were regularly observed in the vicinity of the 
POA with frequent observations near the mouth of Ship Creek, located 
approximately 700 m southeast of the SFD location. From 27 April 
through 24 November 2020, a total of 340 individual harbor seals were 
observed (61 North Environmental, 2021). An additional seven 
unidentified pinnipeds were observed that could have been Steller sea 
lions or harbor seals. Harbor seals were observed almost daily during 
construction, with 54 individuals documented in July, 66 documented in 
August, and 44 sighted in September (61North Environmental, 2021).
    The most current population trend estimate of the Cook Inlet/
Shelikof Strait stock is approximately -111 seals per year, with a 
probability that the stock is decreasing of 0.609 (Muto et al., 2020a). 
The estimated level of human-caused mortality and serious injury for 
this stock is 234 seals, of which 233 seals are taken for subsistence 
uses. Between 2013 and 2017, there were two reports of Cook Inlet/
Shelikof Strait harbor seal mortality and serious injury due to 
entanglements in fishing gear, including one in a Cook Inlet salmon set 
gillnet in 2014 and one in an unidentified net in 2017, resulting in a 
mean annual mortality and serious injury rate of 0.4 harbor seals from 
this stock due to interactions with unknown (commercial, recreational, 
or subsistence) fisheries (Muto et al., 2020a). Additional potential 
threats most likely to result in direct human-caused mortality or 
serious injury for all stocks of harbor seals in Alaska include 
unmonitored subsistence harvests, incidental takes in commercial 
fisheries, illegal shooting, and entanglements in marine debris (Delean 
et al., 2020, Muto et al., 2020a). Disturbance by cruise vessels is an 
additional threat for harbor seal stocks that occur in glacial fjords 
(Jansen et al., 2010, 2015; Matthews et

[[Page 31881]]

al., 2016). The average annual harvest of this stock of harbor seals 
between 2004 and 2008 was 233 seals per year. The annual harvest in 
2014 was 104 seals (Muto et al., 2020a). This stock is not designated 
as depleted under the MMPA or listed as threatened or endangered under 
the ESA, and the minimum estimate of the mean annual level of human-
caused mortality and serious injury does not exceed PBR; therefore, the 
Cook Inlet/Shelikof Strait stock of harbor seals is not classified as a 
strategic stock (Muto et al., 2020a).

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 3.

                  Table 3--Marine Mammal Hearing Groups
                              [NMFS, 2018]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen   7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans           150 Hz to 160 kHz.
 (dolphins, toothed whales, beaked
 whales, bottlenose whales).
High-frequency (HF) cetaceans (true    275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus
 cruciger & L. australis).
Phocid pinnipeds (PW) (underwater)     50 Hz to 86 kHz.
 (true seals).
Otariid pinnipeds (OW) (underwater)    60 Hz to 39 kHz.
 (sea lions and fur seals).
------------------------------------------------------------------------
* Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al., 2007) and PW pinniped (approximation).

    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018) for a review of available information. 
Six marine mammal species (four cetacean and two pinniped (one otariid 
and one phocid) species) have the reasonable potential to co-occur with 
the proposed construction activities. Please refer to Table 2. Of the 
cetacean species that may be present, one is classified as low-
frequency cetaceans (i.e., all mysticete species), two are classified 
as mid-frequency cetaceans (i.e., all delphinid and ziphiid species and 
the sperm whale), and one is classified as high-frequency cetaceans 
(i.e., harbor porpoise and Kogia spp.).

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 primary relevant stressor to marine mammals from the proposed 
activity is the introduction of noise into the aquatic environment; 
therefore, we focus our impact analysis on the effects of anthropogenic 
noise on marine mammals. To better understand the potential impacts of 
exposure to pile driving noise, we describe sound source 
characteristics below. Specifically, we look at the following two ways 
to characterize sound: by its temporal (i.e., continuous or 
intermittent) and its pulse (i.e., impulsive or non-impulsive) 
properties. Continuous sounds are those whose sound pressure level 
remains above that of the ambient sound, with negligibly small 
fluctuations in level (NIOSH, 1998; ANSI, 2005), while intermittent 
sounds are defined as sounds with interrupted levels of low or no sound 
(NIOSH, 1998). Impulsive sounds, such as those generated by impact pile 
driving, are typically transient, brief (<1 sec), broadband, and 
consist of a high peak pressure with rapid rise time and rapid decay 
(ANSI, 1986; NIOSH, 1998). The majority of energy in pile impact pulses 
is at frequencies below 500 hertz (Hz). Impulsive sounds, by 
definition, are intermittent. Non-impulsive sounds, such as those 
generated by vibratory pile driving, can be broadband, narrowband or 
tonal, brief or prolonged, and typically do not have a high peak sound 
pressure with rapid rise/decay time that impulsive sounds do (ANSI, 
1995; NIOSH, 1998). Non-impulsive sounds can be intermittent or 
continuous. Similar to impact pile driving, vibratory pile driving 
generates low frequency sounds. Vibratory pile driving is considered a 
non-impulsive, continuous source. Discussion on the appropriate 
harassment threshold associated with these types of sources

[[Page 31882]]

based on these characteristics can be found in the Estimated Take 
section.
    Potential Effects of Pile Driving--In general, the effects of 
sounds from pile driving to marine mammals might result in one or more 
of the following: Temporary or permanent hearing impairment, non-
auditory physical or physiological effects, behavioral disturbance, and 
masking (Richardson et al., 1995; Nowacek et al., 2007; Southall et 
al., 2007). The potential for and magnitude of these effects are 
dependent on several factors, including receiver characteristics (e.g., 
age, size, depth of the marine mammal receiving the sound during 
exposure); the energy needed to drive the pile (usually related to pile 
size, depth driven, and substrate), the standoff distance between the 
pile and receiver; and the sound propagation properties of the 
environment.
    Impacts to marine mammals from pile driving activities are expected 
to result primarily from acoustic pathways. As such, the degree of 
effect is intrinsically related to the received level and duration of 
the sound exposure, which are in turn influenced by the distance 
between the animal and the source. The further away from the source, 
the less intense the exposure should be. The type of pile driving also 
influences the type of impacts, for example, exposure to impact pile 
driving may result in temporary or permanent hearing impairment, while 
auditory impacts are unlikely to result from exposure to vibratory pile 
driving. The substrate and depth of the habitat affect the sound 
propagation properties of the environment. Shallow environments are 
typically more structurally complex, which leads to rapid sound 
attenuation. In addition, substrates that are soft (e.g., sand) absorb 
or attenuate the sound more readily than hard substrates (e.g., rock) 
which may reflect the acoustic wave. Soft porous substrates also likely 
require less time to drive the pile, and possibly less forceful 
equipment, which ultimately decrease the intensity of the acoustic 
source.
    Richardson et al., (1995) described zones of increasing intensity 
of effect that might be expected to occur, in relation to distance from 
a source and assuming that the signal is within an animal's hearing 
range. First is the area within which the acoustic signal would be 
audible (potentially perceived) to the animal, but not strong enough to 
elicit any overt behavioral or physiological response. The next zone 
corresponds with the area where the signal is audible to the animal and 
of sufficient intensity to elicit behavioral or physiological 
responsiveness. Third is a zone within which, for signals of high 
intensity, the received level is sufficient to potentially cause 
discomfort or tissue damage to auditory or other systems. Overlaying 
these zones to a certain extent is the area within which masking (i.e., 
when a sound interferes with or masks the ability of an animal to 
detect a signal of interest that is above the absolute hearing 
threshold) may occur; the masking zone may be highly variable in size.
    We describe the more severe effects (i.e., permanent hearing 
impairment, certain non-auditory physical or physiological effects) 
only briefly as we do not expect that there is a reasonable likelihood 
that POA's activities would result in such effects (see below for 
further discussion).
    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, 2016b). The amount of 
threshold shift is customarily expressed in dB (ANSI 1995, Yost 2007). 
A TS can be permanent (PTS) or temporary (TTS). As described in NMFS 
(2018), there are numerous factors to consider when examining the 
consequence of TS, including, but not limited to, the signal temporal 
pattern (e.g., impulsive or non-impulsive), likelihood an individual 
would be exposed for a long enough duration or to a high enough level 
to induce a TS, the magnitude of the TS, time to recovery (seconds to 
minutes or hours to days), the frequency range of the exposure (i.e., 
spectral content), the hearing and vocalization frequency range of the 
exposed species relative to the signal's frequency spectrum (i.e., how 
animal uses sound within the frequency band of the signal; e.g., 
Kastelein et al., 2014), and the overlap between the animal and the 
source (e.g., spatial, temporal, and spectral). When analyzing the 
auditory effects of noise exposure, it is often helpful to broadly 
categorize sound as either impulsive--noise with high peak sound 
pressure, short duration, fast rise-time, and broad frequency content--
or non-impulsive. When considering auditory effects, vibratory pile 
driving is considered a non-impulsive source while impact pile driving 
is treated as an impulsive source.
    Permanent Threshold Shift--NMFS defines PTS as a permanent, 
irreversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Available data 
from humans and other terrestrial mammals indicate that a 40 dB 
threshold shift approximates PTS onset (see NMFS 2018 for review).
    Temporary Threshold Shift--NMFS defines TTS as a temporary, 
reversible increase in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). Based on data from 
cetacean TTS measurements (see Finneran 2015 for a review), a TTS of 6 
dB is considered the minimum threshold shift clearly larger than any 
day-to-day or session-to-session variation in a subject's normal 
hearing ability (Schlundt et al., 2000; Finneran et al., 2000; Finneran 
et al., 2002).
    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.
    Schlundt et al. (2000) performed a study exposing five bottlenose 
dolphins and two beluga whales (same individuals as Finneran's studies) 
to intense one second tones at different frequencies. The resulting 
levels of fatiguing stimuli necessary to induce 6 dB or larger masked 
TTSs were generally between 192 and 201 dB re: 1 microPascal ([mu]Pa). 
Dolphins began to exhibit altered behavior at levels of 178-193 dB re: 
1[mu]Pa and above; beluga whales displayed altered behavior at 180-196 
dB re: 1 [mu]Pa and above. At the conclusion of the study, all 
thresholds were at baseline values.
    There are a limited number of studies investigating the potential 
for cetacean TTS from pile driving and only one has elicited a small 
amount of TTS in a single harbor porpoise individual (Kastelein et al., 
2015). However,

[[Page 31883]]

captive bottlenose dolphins and beluga whales have exhibited changes in 
behavior when exposed to pulsed sounds (Finneran et al., 2000, 2002, 
2005). The animals tolerated high received levels of sound before 
exhibiting aversive behaviors. Experiments on a beluga whale showed 
that exposure to a single watergun impulse at a received level of 207 
kiloPascal (kPa) (30 psi) p-p, which is equivalent to 228 dB p-p, 
resulted in a 7 and 6 dB TTS in the beluga whale at 0.4 and 30 kHz, 
respectively. Thresholds returned to within 2 dB of the pre-exposure 
level within four minutes of the exposure (Finneran et al., 2002). 
Although the source level of pile driving from one hammer strike is 
expected to be lower than the single watergun impulse cited here, 
animals being exposed for a prolonged period to repeated hammer strikes 
could receive more sound exposure in terms of SEL than from the single 
watergun impulse (estimated at 188 dB re 1 [mu]Pa\2\-s) in the 
aforementioned experiment (Finneran et al., 2002). Results of these 
studies suggest odontocetes are susceptible to TTS from pile driving, 
but that they seem to recover quickly from at least small amounts of 
TTS.
    Behavioral Responses--Behavioral disturbance may include a variety 
of effects, including subtle changes in behavior (e.g., minor or brief 
avoidance of an area or changes in vocalizations), more conspicuous 
changes in similar behavioral activities, and more sustained and/or 
potentially severe reactions, such as displacement from or abandonment 
of high-quality habitat. 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.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al., 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al., 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that

[[Page 31884]]

respiration rates may either be unaffected or could increase, depending 
on the species and signal characteristics, again highlighting the 
importance in understanding species differences in the tolerance of 
underwater noise when determining the potential for impacts resulting 
from anthropogenic sound exposure (e.g., Kastelein et al., 2001, 2005b, 
2006; Gailey et al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
(Eubalaena glacialis) have been observed to shift the frequency content 
of their calls upward while reducing the rate of calling in areas of 
increased anthropogenic noise (Parks et al., 2007). In some cases, 
animals may cease sound production during production of aversive 
signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
(Eschrictius robustus) are known to change direction--deflecting from 
customary migratory paths--in order to avoid noise from seismic surveys 
(Malme et al., 1984). Avoidance may be short-term, with animals 
returning to the area once the noise has ceased (e.g., Bowles et al., 
1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey 
et al., 2007). Longer-term displacement is possible, however, which may 
lead to changes in abundance or distribution patterns of the affected 
species in the affected region if habituation to the presence of the 
sound does not occur (e.g., Blackwell et al., 2004; Bejder et al., 
2006; Teilmann et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996). The result of a flight response could range from 
brief, temporary exertion and displacement from the area where the 
signal provokes flight to, in extreme cases, marine mammal strandings 
(Evans and England, 2001). However, it should be noted that response to 
a perceived predator does not necessarily invoke flight (Ford and 
Reeves, 2008), and whether individuals are solitary or in groups may 
influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil 1997; Fritz et al, 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    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, Wright et al., 2007) and, more rarely, studied in 
wild populations (e.g.,

[[Page 31885]]

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. 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).
    Specific to CIBWs, we have several years of marine mammal 
monitoring data demonstrating the behavioral responses to pile driving 
at the POA. Previous pile driving activities range from the 
installation and removal of sheet pile driving to installation of 48-in 
pipe piles with both vibratory and impact hammers, and vibratory 
installation of 72-inch air bubble casings. Kendall and Cornick (2015) 
provide a comprehensive overview of four years of scientific marine 
mammal monitoring conducted during the POA's Expansion Project. These 
were observations made independent of pile driving activities (i.e., 
not construction based PSOs). The authors investigated CIBWs behavior 
before and during pile driving activity at the POA. Sighting rates, 
mean sighting duration, behavior, mean group size, group composition, 
and group formation were compared between the two periods. A total of 
about 2,329 h of sampling effort was completed across 349 d from 2005 
to 2009. Overall, 687 whales in 177 groups were documented during the 
69 days that whales were sighted. A total of 353 and 1,663 hours of 
pile driving took place in 2008 and 2009, respectively. There was no 
relationship between monthly CIBW sighting rates and monthly pile 
driving rates (r = 0.19, p = 0.37). Sighting rates before (n = 12; 0.06 
 0.01) and during (n = 13; 0.01  0.03) pile 
driving were not significantly different. However, sighting duration of 
CIBWs decreased significantly during pile driving (39  6 
min before and 18  3 min during). There were also 
significant differences in behavior before versus during pile driving. 
CIBWs primarily traveled through the study area both before and during 
pile driving; however, traveling increased relative to other behaviors 
during pile driving. Suspected feeding decreased during pile driving 
although the sample size was low as feeding was observed on only two 
occasions before pile driving and on zero occasions during pile 
driving. Documentation of milling began in 2008 and was observed on 21 
occasions. No acute behavioral responses were documented. Mean group 
size decreased during pile driving; however, this difference was not 
statistically significant. There were significant differences in group 
composition before and during pile driving between monthly CIBW 
sighting rates and monthly pile driving rates with more white (i.e., 
older) animals being present during pile driving.
    During PCT construction monitoring, behaviors of CIBWs groups were 
compared by month and by construction activity (61 North Environmental, 
2021). Little variability was evident in the behaviors recorded from 
month to month, or between sightings that coincided with in-water pile 
installation and removal and those that did not. One minor difference 
was a slightly higher incidence of milling behavior during the periods 
of no pile driving and slightly higher rates of traveling behavior 
during periods when CIBWs were potential disturbed by pile driving.
    Acoustically, Kendall et al. (2013) only recorded echolocation 
clicks and no whistles or noisy vocalizations near construction 
activity at the POA. CIBWs have been occasionally documented to forage 
around Ship Creek (south of the POA) but, during pile driving, may 
choose to move past the POA to other, potentially richer, feeding areas 
further into Knik Arm (e.g., Six Mile Creek, Eagle River, Eklutna 
River). These locations contain predictable salmon runs (ADF&G, 2010), 
an important food source for CIBWs, and the timing of these runs has 
been correlated with CIBW movements into the upper reaches of Knik Arm 
(Ezer et al., 2013).

Auditory Masking

    Since many marine mammals rely on sound to find prey, moderate 
social interactions, and facilitate mating (Tyack, 2008), noise from 
anthropogenic sound sources can interfere with these functions, but 
only if the noise spectrum overlaps with the hearing sensitivity of the 
marine mammal (Southall et al., 2007; Clark et al., 2009; Hatch et al., 
2012). Chronic exposure to excessive, though not high-intensity, noise 
could cause masking at particular frequencies for marine mammals that 
utilize sound for vital biological functions (Clark et al., 2009). 
Acoustic masking is when other noises such as from human sources 
interfere with animal detection of acoustic signals such as 
communication calls, echolocation sounds, and environmental sounds 
important to marine mammals. Therefore, under certain circumstances, 
marine mammals whose acoustical sensors or environment are being 
severely masked could also be impaired from maximizing their 
performance fitness in survival and reproduction.
    Masking, which can occur over large temporal and spatial scales, 
can potentially affect the species at population, community, or even 
ecosystem levels, as well as individual levels. Masking affects both 
senders and receivers of the signals and could have long-term chronic 
effects on marine mammal species and populations. Masking occurs at the 
frequency band which the animals utilize so the frequency range of the 
potentially masking sound is important in determining any potential 
behavioral impacts. Pile driving generates low frequency sounds; 
therefore, mysticete foraging is likely more affected than odontocetes 
given very high frequency echolocation clicks (typically associated 
with odontocete foraging) are likely unmasked to any significant 
degree. However, lower frequency man-made sounds may affect 
communication signals when they occur near the sound band and thus 
reduce the communication space of animals (e.g., Clark et al., 2009) 
and cause increased stress levels (e.g., Foote et al., 2004; Holt et 
al., 2009).
    Moreover, even within a given species, different types of man-made 
noises may results in varying degrees of masking. For example, Erbe 
(1997) and Erbe and Farmer (1998) analyzed the effect of masking of 
beluga calls by exposing a trained beluga to icebreaker propeller 
noise, an icebreaker's bubbler system, and ambient Arctic ice cracking 
noise, and found that the latter was the least problematic for the 
whale detecting the calls. Sheifele et al. (2005) studied a population 
of belugas in the St. Lawrence River Estuary to determine whether 
beluga vocalizations showed intensity changes in response to shipping 
noise. This type of behavior has been observed in humans and is known 
as the Lombard vocal response (Lombard, 1911). Sheifele et al. (2005) 
demonstrated that shipping noise did cause belugas to vocalize louder. 
The acoustic behavior of this same population of belugas was studied in 
the presence of ferry and small boat noise. Lesage et al. (1999) 
described more persistent vocal responses when whales were exposed to 
the ferry than to the small-boat noise. These included a progressive 
reduction in calling rate while vessels were approaching, an increase 
in the repetition of specific calls, and a shift to higher frequency 
bands used by vocalizing animals when vessels were close to the whales. 
The authors concluded that these changes,

[[Page 31886]]

and the reduction in calling rate to almost silence, may reduce 
communication efficiency which is critical for a species of a 
gregarious nature. However, the authors also stated that because of the 
gregarious nature of belugas, this ``would not pose a serious problem 
for intraherd communication'' of belugas given the short distance 
between group members, and concluded a noise source would have to be 
very close to potentially limit any communication within the beluga 
group (Lesage et al., 1999). However, increasing the intensity or 
repetition rate, or shifting to higher frequencies when exposed to 
shipping noise (from merchant, whale watching, ferry and small boats), 
is indicative of an increase of energy costs (Bradbury and Vehrencamp, 
1998).
    Marine mammals in Cook Inlet are continuously exposed to 
anthropogenic noise which may lead to some habituation but is also a 
source of masking (Castellote et al., 2019, Mooney et al., 2020). A 
subsample (8756 hours) of the acoustic recordings collected by the Cook 
Inlet Beluga Acoustics research program in Cook Inlet, Alaska, from 
July 2008 to May 2013, were analyzed to describe anthropogenic sources 
of underwater noise, acoustic characteristics, and frequency of 
occurrence and evaluate the potential for acoustic impact to CIBWs. As 
described in Castellote et al., (2016), a total of 13 sources of noise 
were identified: commercial ship, dredging, helicopter, jet aircraft 
(commercial or non-fighter), jet aircraft (military fighter), outboard 
engine (small skiffs, rafts), pile driving, propeller aircraft, sub-
bottom profiler, unclassified machinery (continuous mechanical sound; 
e.g., engine), unidentified `clank' or `bang' (impulsive mechanical 
sound; e.g., barge dumping), unidentified (unclassifiable anthropogenic 
sound), unknown up- or down-sweep (modulated tone of mechanical origin; 
e.g., hydraulics). A total of 6263 anthropogenic acoustic events were 
detected and classified, which had a total duration of 1025 hours and 
represented 11.7 percent of the sound recordings analyzed. There was 
strong variability in source diversity, loudness, distribution, and 
seasonal occurrence of noise, which reflects the many different 
activities within the Cook Inlet. Cairn Point was the location where 
the loudness and duration of commercial ship noise events were most 
concentrated, due to activities at the POA. This specific source of 
anthropogenic noise was present in the recordings from all months 
analyzed, with highest levels in August. In addition to the 
concentrated shipping noise at Cairn Point, a combination of unknown 
noise classes occurred in this area, particularly during summer. 
Specifically, unknown up or down sweeps, unidentified, unclassed 
machinery, and unidentified clank or bang noise classes were all 
documented. In contrast, Eagle River (north of the POA and where CIBWs 
concentrate to forage) was the quietest of all sampled locations.
    Sensitivity in CIBW hearing may make them more susceptible to 
masking. The first empirical hearing data of a CIBW was recently 
obtained by Mooney et al., (2020), who used auditory evoked potentials 
to measure the hearing of a wild, stranded CIBW as part of its 
rehabilitation assessment. The CIBW exhibited broadband (4-128 kHz) and 
sensitive hearing (<80 dB) for a wide range of frequencies (16-80 kHz), 
with the audiogram shape and waveforms generally reflective of a 
sensitive odontocete's auditory system without substantial hearing loss 
(Mooney et al., 2020). This sensitivity suggests that CIBWs are 
susceptible to masking from a variety of anthropogenic sources in Cook 
Inlet.
    Potential Pile Driving Effects on Prey--Pile driving produces 
continuous, non-impulsive (i.e., vibratory pile driving) sounds and 
intermittent, pulsed (i.e., impact 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 pressure 
levels (SPLs) of sufficient strength have been known to cause injury to 
fish and fish mortality (summarized in Popper et al., 2014). The most 
likely impact to fish from pile driving activities at the project area 
would be temporary behavioral avoidance of the area. The duration of 
fish avoidance of this area after pile driving stops is unknown, but a 
rapid return to normal recruitment, distribution and behavior is 
anticipated.
    As discussed in the Marine Mammal section above, NMFS designated 
CIBW critical habitat in Knik Arm. Knik Arm is Type 1 habitat for the 
CIBWs, which means it is the most valuable, used intensively by CIBWs 
from spring through fall for foraging and nursery habitat. However, the 
POA, the adjacent navigation channel, and the turning basin were 
excluded from critical habitat designation due to national security 
concerns (76 FR 20180; April 11, 2011). Foraging primarily occurs at 
river mouths (e.g., Susitna Delta, Eagle River flats) which are 
unlikely to be influenced by pile driving activities. The Susitna Delta 
is more than 20 km from the POA and Cairn Point is likely to impede any 
pile driving noise from propagating into northern Knik Arm. Of the 245 
CIBW groups observed during PCT construction monitoring, only two 
groups were suspected to be feeding (61 North Environmental, 2021). One 
of these groups (n = 4 CIBWs) was observed on May 7, 2020, a non-pile 
driving day, approximately 142 m away from the PCT. The other group (n 
= 3 CIBWs) was observed on July 14, 2020 during impact installation of 
an attenuated 48-inch pile. These CIBWs were suspected to be foraging 
in Bootleggers Cove, approximately 1,399 m way from the PCT and outside 
the respective Level B harassment zone (824 m). It was unclear whether 
or not feeding occurred during pile driving activities (61 North 
Environmental, 2021).
    Acoustic habitat is the soundscape which encompasses all of the 
sound present in a particular location and time, as a whole, when 
considered from the perspective of the animals experiencing it. Animals 
produce sound for, or listen for sounds produced by, conspecifics 
(communication during feeding, mating, and other social activities), 
other animals (finding prey or avoiding predators) and the physical 
environment (finding suitable habitats, navigating). Together, sounds 
made by animals and the geophysical environment (e.g., produced by 
earthquakes, lightning, wind, rain, waves) make up the natural 
contributions to the total acoustics of a place. These acoustic 
conditions, termed acoustic habitat, are one attribute of an animal's 
total habitat. Soundscapes are also defined by, and acoustic habitat 
influenced by, the total contribution of anthropogenic sound. This may 
include incidental emissions from sources such as vessel traffic or may 
be intentionally introduced to the marine environment for data 
acquisition purposes (as in the use of airgun arrays or other sources). 
Anthropogenic noise varies widely in its frequency content, duration, 
and loudness and these characteristics greatly influence the potential 
habitat-mediated effects to marine mammals (please see also the

[[Page 31887]]

previous discussion on masking under ``Acoustic Effects''), which may 
range from local effects for brief periods of time to chronic effects 
over large areas and for long durations. Depending on the extent of 
effects to habitat, animals may alter their communications signals 
(thereby potentially expending additional energy) or miss acoustic cues 
(either conspecific or adventitious). For more detail on these concepts 
see, e.g., Barber et al., 2010; Pijanowski et al., 2011; Francis and 
Barber, 2013; Lillis et al., 2014.
    CIBW foraging habitat is limited at the POA given the highly 
industrialized area. However, foraging habitat exists near the POA, 
including Ship Creek and to the north of Cairn Point. Potential impacts 
to foraging habitat include increased turbidity and elevation in noise 
levels during pile driving. While the POA is building a new dock, it is 
removing the float and gangway of the existing dock and permanent 
impacts from the presence of the new dock are negligible. Here, we 
focus on construction impacts such as increased turbidity and reference 
the section on acoustic habitat impacts above.
    Pile installation may temporarily increase turbidity resulting from 
suspended sediments. Any increases would be temporary, localized, and 
minimal. POA must comply with state water quality standards during 
these operations by limiting the extent of turbidity to the immediate 
project area. In general, turbidity associated with pile installation 
is localized to about a 25-foot (7.6 m) radius around the pile (Everitt 
et al., 1980). Cetaceans are not expected to be close enough to the 
project activity areas to experience effects of turbidity, and any 
small cetaceans and pinnipeds could avoid localized areas of turbidity. 
Therefore, the impact from increased turbidity levels is expected to be 
discountable to marine mammals. No turbidity impacts to Ship Creek or 
critical CIBW foraging habitats are anticipated.
    In summary, activities associated with the proposed SFD project are 
not likely to have a permanent, adverse effect on marine mammal habitat 
or populations of fish species or on the quality of acoustic habitat. 
Marine mammals may choose to not forage in close proximity to the SFD 
site during pile driving; however, the POA is not a critical foraging 
location for any marine mammal species. As discussed above, harbor 
seals primarily use Ship Creek as foraging habitat within Knik Arm. 
CIBWs utilize Eagle Bay and rivers north of the POA which are not 
expected to be ensonified by the SFD project. Therefore, no impacts to 
critical foraging grounds are anticipated.

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 not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as pile 
driving has the potential to result in disruption of behavioral 
patterns for individual marine mammals, either directly or as a result 
of TTS. There is also some potential for auditory injury (Level A 
harassment) to result, primarily for mysticetes, high frequency 
species, and phocids because predicted auditory injury zones are larger 
than for mid-frequency species and otariids. Auditory injury is 
unlikely to occur for mid-frequency species and otariids. 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 (root mean square; 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. This take estimation 
includes disruption of behavioral patterns resulting directly in 
response to noise exposure (e.g., avoidance), as well as that resulting 
indirectly from associated impacts such as TTS or masking. However, 
ambient noise levels within Knik Arm are above the 120-dB threshold, 
and therefore, for purposes of this analysis, NMFS considers received 
levels above those of the measured ambient noise (122.2 dB) to 
constitute Level B harassment of marine mammals incidental to 
continuous noise, including vibratory pile driving.
    Results from recent acoustic monitoring conducted at the port are 
presented in Austin et al. (2016) and Denes et al. (2016) wherein noise 
levels were measured in absence of pile driving from May 27 through May 
30, 2016 at two locations: Ambient-Dock and Ambient-Offshore. NMFS 
considers the median sound levels to be most appropriate when 
considering background noise levels for purposes of

[[Page 31888]]

evaluating the potential impacts of the POA's SFD Project on marine 
mammals (NMFS, 2012). By using the median value, which is the 50th 
percentile of the measurements, for ambient noise level, one will be 
able to eliminate the few transient loud identifiable events that do 
not represent the true ambient condition of the area. This is relevant 
because during two of the four days (50 percent) when background 
measurement data were being collected, the U.S. Army Corps of Engineers 
was dredging Terminal 3 (located just north of the Ambient-Offshore 
hydrophone) for 24 hours per day with two 1-hour breaks for crew 
change. On the last two days of data collection, no dredging was 
occurring. Therefore, the median provides a better representation of 
background noise levels when the SFD project would be occurring. With 
regard to spatial considerations of the measurements, the Ambient-
Offshore location is most applicable to this discussion (NMFS, 2012). 
The median ambient noise level collected over four days at the end of 
May at the Ambient-Offshore hydrophone was 122.2 dB. We note the 
Ambient-Dock location was quieter, with a median of 117 dB; however, 
that hydrophone was placed very close to the dock and not where we 
would expect Level B harassment to occur given mitigation measures 
(e.g., shut downs). We also recognize that during Phase 1 PCT acoustic 
monitoring, noise levels in Knik Arm absent pile driving were collected 
(Reyff et al., 2021); however, the Phase 1 PCT IHA did not require 
ambient noise measurements to be collected. These measurements were not 
collected in accordance to NMFS (2012) guidance for measuring ambient 
noise and thus cannot be used here for that purpose. If additional data 
collected in the future warrant revisiting this issue, NMFS may adjust 
the 122.2 dB rms Level B harassment threshold.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Version 2.0) (NMFS, 2018) identifies dual criteria to 
assess auditory injury (Level A harassment) to five different marine 
mammal groups (based on hearing sensitivity) as a result of exposure to 
noise from two different types of sources (impulsive or non-impulsive). 
The POA's proposed activity includes the use of non-impulsive 
(vibratory pile driving) sources.
    These thresholds are provided in Table 4 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 4--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 estimated sound source levels (SSL) proposed by the POA and 
used in this assessment for vibratory installation of attenuated piles 
are based on sound levels of 24-inch and 36-inch piles measured during 
a sound source verification (SSV) study conducted during Phase 1 of the 
POA's 2020 PCT project (Reyff et al., 2021). For the 24-inch template 
piles, SSLs measured for 24-inch PCT template piles by Reyff et al. 
(2021) were selected for use as a proxy for 24-inch SFD template piles 
based on anticipated pile function (Table 5). These piles were driven 
for 19.2 to 25.6 minutes, using an APE 200-6 vibratory hammer and a 
confined bubble curtain (Reyff et al., 2021). For the 36-inch template 
piles, SSLs are assumed to be similar to the SSLs measured for 36-inch 
trestle piles installed during PCT construction (note no 36-inch 
template piles were measured in Reyffe et al., 2021) (Table 5). These 
piles were installed with a confined bubble curtain using an APE 300-6 
vibratory hammer; driving times ranged from 22.1 to 36.4 minutes. It is 
assumed that SLLs during pile installation and removal for both pile 
sizes will be similar.
    No unattenuated 24-inch or 36-inch piles were installed during 
either the TPP (Austin et al., 2016) or PCT SSV projects (Reyeff et 
al., 2021). Instead, SSL measurements collected during marine 
construction projects conducted by the U.S. Navy for the Naval Base 
Kitsap at Bangor EHW-2 Project (U.S. Navy, 2015), which were installed 
at similar depths and in a similar marine environment, were used as 
proxies for vibratory and impact installation of unattenuated piles for 
the SFD project (Table 5). It is assumed that SSLs during vibratory 
pile installation and removal will be similar.
    SSLs measurements for attenuated 24-inch and 36-inch piles driven 
with an impact hammer also were not measured during either the TPP 
(Austin et al., 2016) or PCT SSV projects (Reyeff et al., 2021). SSL 
measurements for impact

[[Page 31889]]

installation made by Ryeff et al. (2021) were on piles using a confined 
bubble curtain system with 48-inch piles; whereas, an unconfined system 
is proposed with smaller piles for the SFD. In a confined bubble 
curtain system, the bubbles are confined to the area around the pile 
with a flexible material or rigid pipe; however, in an unconfined 
bubble curtain system, there is no such system for restraining the 
bubbles (NAVFAC SW, 2020). Unconfined bubble curtain performance is 
highly variable and effectiveness depends on the system design and on-
site conditions such as water depth, water current velocity, substrate 
and underlying geology. The unconfined systems typically consist of 
vertically stacked bubble rings, while the confined systems are a 
single ring at the bottom placed inside a casing that encompasses the 
pile. The U.S. Navy (2015) summarized several studies which 
demonstrated that unconfined bubble curtains performance can be 
effective in attenuating underwater noise from impact pile 
installation. They found bubble curtain performance to be highly 
variable, but based on information from the Bangor Naval Base Test Pile 
Program, found an average peak SPL reduction of 8 dB to 10 dB at 10 m 
would be an achievable level of attenuation for steel pipe piles of 36- 
and 48-inches in diameter. The efficiency of bubble curtains with 24-
inch piles was not examined by the U.S. Navy (2015). Based on these 
analyses, and the effect that local currents may have on the 
distribution of bubbles and thus effectiveness of an unconfined bubble 
curtain, NMFS conservatively applies a 7 dB reduction to the U.S. Navy 
(2015) unattenuated SSLs (Table 5) for attenuated 24-inch and 36-inch 
piles during impact pile driving (Table 5). These SSLs are consistent 
with SSLs previously proposed and authorized by NMFS for POA impact 
pile driving of 24-inch and 36-inch piles (e.g., PCT Final IHA [85 FR 
19294]). Rationale for using a 7 dB reduction has further been provided 
on June 19, 2019, in 84 FR 28474 and on November 25, 2019, in 84 FR 
64833. This reduction is more conservative than the confined bubble 
curtain efficacy reported by Reyff et al. (2021), which ranged from 9 
to 11 dB for peak, rms, and SEL single strike measurements.
    The TL coefficients reported in the PCT SSV are highly variable and 
are generally lower than values previously reported and used in the 
region. For example, Reyff et al. (2021) reported unweighted 
transmission loss coefficients ranging from 8.9 to 16.3 dB SEL and 7.0 
to 16.7 dB rms for impact driving 48-inch attenuated piles. In the PCT 
Final IHA (85 FR 19294), the POA proposed, and NMFS applied, a TL rate 
of 16.85 dB SEL for assessing potential for Level A harassment from 
impact pile driving and a TL rate of 18.35 dB rms when assessing 
potential for Level B harassment from impact pile driving for based on 
Austin et al. (2016) measurements recorded during the TPP on 48-in 
piles. Higher TL rates in Knik Arm are supported by additional studies, 
such as by [Scaron]irovi[cacute] and Kendall (2009), who reported a TL 
of 16.4 dB during impact hammer driving during passive acoustic 
monitoring of the POA Marine Terminal Redevelopment Project, and by 
Blackwell (2005) who reported TLs ranging from 16--18 dB SEL and 21.8 
dB rms for impact and vibratory installation of 36-inch piles, 
respectively, during modifications made to the Port MacKenzie dock. 
After careful inspection of the data presented in the Reyff et al., 
study (including relevant spectrograms), NMFS is concerned that flow 
noise in the far field measurements is negatively biasing the 
regressions derived to infer TL rates. While Reyff et al. (2021) 
discuss attempts they made to remove flow noise from their 
calculations, NMFS could not conclude that these attempts adequately 
removed flow noise from their measurements. Relevant to the SFD, the TL 
calculations of individual vibratory installation of 24-inch template 
piles and 36-inch trestle piles reported by Reyff et al. (2021) were 
also highly variable ranging from 12.5 to 16.6 dB rms and 14.4 to 17.2 
dB rms, respectively. Given this variability and previous data 
suggesting higher TL rates, NMFS has preliminarily determined that 
applying a practical spreading loss model (15logR) to ensonified area 
calculations is most likely the representative scenario in Knik Arm 
(Table 5). The 15 TL coefficient also falls within the range of TL 
coefficients reported in Reyff et al. (2021). We note the POA will 
conduct additional acoustic monitoring during Phase II of the PCT in 
2021 (prior to when the SFD project will commence) and, if warranted, 
these assumptions may be adjusted and resulting harassment isopleths 
modified.

                       Table 5--Estimated Sound Source Levels and Transmission Loss Coefficients With and Without a Bubble Curtain
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
           Method and pile size                                  Unattenuated
                                                                Bubble curtain
--------------------------------------------------------------------------------------------------------------------------------------------------------
                 Vibratory                        Sound level at 10 m
                                               TL coefficient
                                                  Sound level at 10 m
                                               TL coefficient
                                                        (dB rms)
                                                  (dB rms)
                                                        (dB rms)
                                                  (dB rms)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch...................................             \a\ 166.0
                                                  \c\ 15.0
                                                       \b\ 161.4
                                                  \c\ 15.0
24-inch...................................             \a\ 161.0
                                                  \c\ 15.0
                                                       \b\ 158.5
                                                  \c\ 15.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                  Impact                                         Unattenuated
                                                                Bubble curtain
                                           -------------------------------------------------------------------------------------------------------------
                                                  Sound level at 10 m
                                               TL coefficient
                                                  Sound level at 10 m
                                               TL coefficient
                                           -------------------------------------------------------------------------------------------------------------
                                              dB rms     dB SEL    dB Peak     dB rms     dB SEL     dB rms     dB SEL    dB peak     dB rms     dB SEL
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch...................................  \a\ 194.0  \a\ 184.0  \a\ 211.0   \c\ 15.0   \c\ 15.0  \a\ 187.0  \a\ 177.0  \a\ 204.0   \c\ 15.0   \c\ 15.0
24-inch...................................  \a\ 193.0  \a\ 181.0  \a\ 210.0   \c\ 15.0   \c\ 15.0  \a\ 186.0  \a\ 174.0  \a\ 203.0   \c\ 15.0   \c\ 15.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ U.S. Navy 2015.
\b\ Reyff et al., 2021.
\c\ Practical spreading loss model.

    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

[[Page 31890]]

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 in Table 6.

                                      Table 6--NMFS User Spreadsheet Inputs
----------------------------------------------------------------------------------------------------------------
                                        24-Inch         24-Inch (bubble         36-Inch         36-Inch (bubble
                                    (unattenuated)         curtain)         (unattenuated)         curtain)
----------------------------------------------------------------------------------------------------------------
                                 User Spreadsheet Input: Vibratory Pile Driving
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............  A.1) Non-Impul,     A.1) Non-Impul,     A.1) Non-Impul,     A.1) Non-Impul,
                                   Stat, Cont.         Stat, Cont.         Stat, Cont.         Stat, Cont.
Source Level (SPL RMS)..........  161...............  158.5.............  166...............  161.4.
Transmission Loss Coefficient...  15................  15................  15................  15.
Weighting Factor Adjustment       2.5...............  2.5...............  2.5...............  2.5.
 (kHz).
Time to install/remove single     45/75.............  45/75.............  45/75.............  45/75.
 pile (minutes).
Piles to install/remove per day.  1/1...............  1-2/1-3...........  1/1...............  1-3/1-3.
----------------------------------------------------------------------------------------------------------------
                                   User Spreadsheet Input: Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............  E.1) Impact pile    E.1) Impact pile    E.1) Impact pile    E.1) Impact pile
                                   driving.            driving.            driving.            driving.
Source Level (Single Strike/shot  181...............  174...............  184...............  177.
 SEL).
Transmission Loss Coefficient...  15................  15................  15................  15.
Weighting Factor Adjustment       2.................  2.................  2.................  2.
 (kHz).
Number of strikes pile..........  1000..............  1000..............  1000..............  1000.
Piles per day...................  1.................  1.................  1.................  1.
----------------------------------------------------------------------------------------------------------------

    To calculate the Level B harassment isopleths, NMFS considered 
SPLrms source levels and the corresponding TL coefficients (dB rms; 
Table 5) for impact and vibratory pile driving, respectively. The 
resulting Level A harassment and Level B harassment isopleths are 
presented in Table 7.

           Table 7--Distances to Level A Harassment, by Hearing Group, and Level B Harassment Thresholds per Pile Type and Installation Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              Level A harassment (m)              Level A
                                                                                  ---------------------------------------------  harassment
                                                          Hammer type      Piles                                                   areas       Level B
            Pile size                 Attenuation       (installation/    per day                                               (km\2\) all   harassment
                                                           removal)                   LF       MF       HF       PW       OW      hearing        (m)
                                                                                                                                   groups
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-inch.........................  Bubble Curtain....  Vibratory                 1        4        1        6        3        1        <0.01        2,631
                                                       (Installation).
                                                                                2        7        1        9        4        1
                                                      Vibratory                 1        6        1        8        4        1
                                                       (Removal).
                                                                                3       12        1       17        7        1
                                                      Impact                    1      251        9      299      135       10        <0.19          542
                                                       (Installation).
                                  Unattenuated......  Vibratory                 1        6        1        9        4        1        <0.01        3,861
                                                       (Installation).
                                                      Vibratory                 1        8        1       12        5        1
                                                       (Removal).
                                                      Impact                    1      735       27      876      394       29        <1.34        1,585
                                                       (Installation).
36-inch.........................  Bubble Curtain....  Vibratory                 1        6        1        9        4        1        <0.01        4,106
                                                       (Installation).
                                                                                2       10        1       15        6        1
                                                                                3       13        2       19        8        1
                                                      Vibratory                 1        9        1       13        6        1
                                                       (Removal).
                                                                                3       18        2       26       11        1
                                                      Impact                    1      398       15      474      213       16        <0.76          631
                                                       (Installation).
                                  Unattenuated......  Vibratory                 1       13        2       18        8        1        <0.01        8,318
                                                       (Installation).
                                                      Vibratory                 1       18        2       26       11        1
                                                       (Removal).
                                                      Impact                    1    1,165       42    1,387      624       46        <3.14        1,848
                                                       (Installation).
--------------------------------------------------------------------------------------------------------------------------------------------------------

Marine Mammal Occurrence and Take Estimation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    For all species of cetaceans other than CIBWs, density data is not 
available for upper Cook Inlet. Therefore, the POA relied on marine 
mammal monitoring data collected during past POA projects. These data 
cover the POAs construction season (April through November) across 
multiple years. Calculations used to estimate exposure from pile 
installation for all marine mammals is described below.

Humpback Whales

    Sightings of humpback whales in the project area are rare, and the 
potential risk of exposure of a humpback whale to sounds exceeding the 
Level B harassment threshold is low. Few, if any, humpback whales are 
expected to approach the project area. However, there were two 
sightings in 2017 of what

[[Page 31891]]

was likely a single individual at the Ship Creek Boat Launch (ABR Inc., 
2017) which is located south of the project area. Based on these data, 
the POA conservatively estimates that up to two individuals could be 
behaviorally harassed during the 24 days of pile driving for the SFD. 
This could include sighting a cow-calf pair on multiple days or 
multiple sightings of single humpback whales. No Level A harassment 
take of humpback whales is anticipated or proposed to be authorized.

Killer Whales

    Few, if any, killer whales are expected to approach the project 
area. No killer whales were sighted during previous monitoring programs 
for the Knik Arm Crossing and POA construction projects, including the 
2016 TPP or during Phase 1 of the PCT project in 20202. The infrequent 
sightings of killer whales that are reported in upper Cook Inlet tend 
to occur when their primary prey (anadromous fish for resident killer 
whales and CIBWs for transient killer whales) are also in the area 
(Shelden et al., 2003). Previous sightings of transient killer whales 
have documented pod sizes in upper Cook Inlet between one and six 
individuals (Shelden et al., 2003). The potential for exposure of 
killer whales within the Level B harassment isopleths is anticipated to 
be extremely low. Level B harassment take is conservatively estimated 
at no more than one small pod (6 individuals). No Level A harassment 
take for killer whales is anticipated or proposed to be authorized due 
to the small Level A harassment zones (Table 7) and implementation of a 
100 m shutdown which is larger than Level A harassment isopleths, and 
described below in the Proposed Mitigation section.

Harbor Porpoise

    Previous monitoring data at the POA were used to evaluate daily 
sighting rates for harbor porpoises in the project area. During most 
years of monitoring, no harbor porpoises were observed; however, during 
Phase 1 of the PCT project (2020), 18 individuals (15 groups) were 
observed near the POA, with group sizes ranging from 1-2 individuals. 
The highest daily sighting rate for any recorded year during pile 
installation and removal associated with the PCT was an average of 0.09 
harbor porpoise per day during 2009 construction monitoring, but this 
value may not account for increased sightings in Upper Cook Inlet or 
range extensions (Shelden et al., 2014). Therefore, the POA estimates 
that one harbor porpoise could be observed every 2 days of pile 
driving. Based on this assumption, the POA has requested, and NMFS is 
proposing to authorize, twelve Level B harassment exposures during the 
24 days of pile driving.
    Harbor porpoises are relatively small cetaceans that move at high 
velocities, which can make their detection and identification at great 
distances difficult. Despite this, PSOs during Phase 1 PCT construction 
monitoring (2020) were able to detect harbor porpoises as far as 6,486 
m from the PCT, indicating that the monitoring methods detailed in the 
Final IHAs for Phase 1 and Phase 2 PCT construction (85 FR 19294), (and 
described below in the Proposed Mitigation section for the SFD) allowed 
for harbor porpoises to be detected at great distances. Therefore, no 
Level A harassment take for harbor porpoises is anticipated or proposed 
to be authorized for the SFD. The POA anticipates that the majority of 
piles will be driven using vibratory methods. Using the NMFS User 
Spreadsheet, vibratory driving 24-inch and 36-inch piles results in 
Level A harassment isopleths that are smaller than the proposed 100 m 
shutdown zone, described below in the Proposed Mitigation section (<=26 
m; Table 7). The Level A harassment isopleths calculated using the NMFS 
User Spreadsheet for impact driving 24-inch and 36-inch piles are 
larger than this 100-m shutdown zone (<=1,387 m; Table 7); however, 
Level A harassment isopleths consider long durations and harbor 
porpoise are likely moving through the area, if present, not lingering. 
Further few harbor porpoises are expected to approach the project area 
and are likely to be sighted prior to entering the Level A harassment 
zone. During Phase 1 PCT construction monitoring (2020) only five 
harbor porpoises were observed near the PCT and within the largest 
Level A harassment zone for SFD (1,387 m; Table 7). Given that the POA 
anticipates that only a small number of piles (up to five), may be 
driven with an impact hammer (requiring up to 20 minutes of impact 
installation each at 1 pile per day), the likelihood that harbor 
porpoises will be in these larger zones is minimized. Accounting for 
measures described below in the Proposed Mitigation section below and 
the low likelihood that individual harbor porpoises would appear 
undetected within the Level A harassment zones, we agree with the POA 
and do not authorize any Level A harassment takes of harbor porpoises 
during the construction of the SFD.

Steller Sea Lion

    Steller sea lions are anticipated to be encountered in low numbers, 
if at all, within the project area. Three sightings of what was likely 
a single individual occurred in the project area in 2009, two sightings 
occurred in 2016, one occurred in 2019, and up to six individuals were 
observed in 2020 (4 in May and 2 in June). Based on observations in 
2016, the POA anticipates an exposure rate of two individuals every 19 
days during SFD pile installation and removal. Based on this rate, the 
POA anticipates that there could be up to four harassment exposures of 
Steller sea lions during the 24 days of SFD pile installation and 
removal.
    Sea lions are known to travel at high speeds, in rapidly changing 
directions, and have the potential to be counted multiple times. 
Because of this the POA anticipates that, despite all precautions, sea 
lions could enter the Level A harassment zone before a shutdown could 
be fully implemented. For example, in 2016 during the POA Test Pile 
Program, a Steller sea lion was first sighted next to a work boat and 
within the Level A harassment zone. Nine PSOs had been monitoring for 
the presence of marine mammals near the construction activities at this 
time, but they did not observe the approaching sea lion. Sea lions are 
known to be curious and willing to approach human activity closely, and 
they can swim with a low profile. The incident was recorded as a Level 
A harassment take and raises concern for the POA that a sighting of a 
Steller sea lion within the Level A harassment zones, while unlikely, 
could occur. While Level A harassment takes are unlikely given the low 
likelihood of sea lions in the project area, the small Level A 
harassment isopleths (<46 m; Table 7), and the proposed mitigation 
measures, including the implementation of shutdown zones and the use of 
PSOs, we propose to authorize the POA's request that a small number of 
Steller sea lions could be exposed to Level A harassment levels. 
Therefore, we propose that two Steller sea lions could be exposed to 
Level A harassment levels and 2 Steller sea lions could be exposed to 
Level B harassment levels.

Harbor Seals

    No known harbor seal haulout or pupping sites occur in the vicinity 
of the POA; therefore, exposure of harbor seals to in-air noise is not 
considered in this application, and no take for in-air exposure is 
requested. Harbor seals are not known to reside in the project area, 
but they are seen regularly near the

[[Page 31892]]

mouth of Ship Creek when salmon are running, from July through 
September. With the exception of newborn pups, all ages and sexes of 
harbor seals could occur in the project area during construction of the 
SFD. Any harassment of harbor seals during pile installation would 
involve a limited number of individuals that may potentially swim 
through the project area or linger near Ship Creek.
    Marine mammal monitoring data were used to examine hourly sighting 
rates for harbor seals in the project area. Sighting rates of harbor 
seals were highly variable and appeared to have increased during 
monitoring between 2005 and 2020 (See Table 4-1 in POA's application). 
It is unknown whether any potential increase was due to local 
population increases or habituation to ongoing construction activities. 
The highest monthly hourly sighting rate (rounded) observed during 
previous monitoring at the POA was used to quantify take of harbor 
seals for pile installation associated with the SFD. This occurred in 
2020 during Phase 1 PCT construction monitoring, when harbor seals were 
observed from May through September. A total of 340 harbor seals were 
observed over 1,237.7 hours of monitoring, at a rate of 0.3 harbor 
seals per hour. The maximum monthly hourly sighting rate occurred in 
September and was 0.51 harbor seals per hour. Based on these data, the 
POA estimates that approximately 1 harbor seal may be observed near the 
project per hour of hammer use. During the 21 hours of anticipated pile 
installation and removal, the POA estimates that up 21 harbor seals 
will be exposed to in-water noise levels exceeding harassment 
thresholds for pile installation and removal during SFD construction.
    All efforts will be taken to shut down prior to a harbor seal 
entering the 100-m shutdown zone and prior to a harbor seal entering 
the Level A harassment zones. However, harbor seals often are curious 
of onshore activities, and previous monitoring suggests that this 
species may mill at the mouth of Ship Creek. It is important to note 
that the mouth of Ship Creek is about 700 m from the southern end of 
the SFD and is outside the Level A harassment zones for harbor seals 
during both unattenuated and attenuated vibratory and impact pile 
installation and removal (Table 7). While exposure is anticipated to be 
minimized because pile installation and removal will occur 
intermittently over the short construction period, the POA is 
requesting Level A harassment take for a small number of harbor seals, 
given the potential difficulty of detecting harbor seals and their 
consistent use of the area. Given that 30 harbor seals (8.6 percent) of 
all harbor seals and unidentified pinnipeds were detected within 624 m, 
the largest Level A harassment zone for SFD, during PCT Phase 1 
construction monitoring (61 North Environmental, 2021), POA requests 
and NMFS proposes to authorize that two harbor seals (8.6 percent of 21 
exposures rounded up) could be exposed to Level A harassment levels and 
19 harbor seals could be exposed to Level B harassment levels.

Beluga Whales

    For CIBWs, we looked at several sources of information on marine 
mammal occurrence in upper Cook Inlet to determine how best to estimate 
the potential for exposure to pile driving noise from the SFD Project. 
In their application, the POA estimated Level B harassment take 
following methods outlined in the PCT final IHA (85 FR 19294), which 
relies on monitoring data of CIBWs published in Kendall and Cornick 
(2015). For the SFD application, POA also considered monitoring data of 
CIBWs collected during Phase 1 of the PCT project (61 North 
Environmental, 2021). These data sets (Kendall and Cornick, 2015, and 
61 North Environmental, 2021) cover all months the POA may be 
conducting pile driving for the SFD and they are based on all animals 
observed during scientific monitoring within the proximity of the SFD 
regardless of distance. Hourly sighting rates for CIBWs for each 
calendar month were calculated using documented hours of observation 
and CIBW sightings from April through November for 2005, 2006, 2008 and 
2009 (Kendall and Cornick, 2015) and 2020 (61 North Environmental, 
2021) (Table 8). The highest calculated monthly hourly sighting rate of 
0.94 whales per hour was used to calculate potential CIBW exposures (21 
hours of pile installation and removal multiplied by 0.94 whales/hour). 
Using this method, the POA estimated that 20 CIBWs (rounded from 19.75) 
could be exposed to the Level B harassment level during pile 
installation and removal associated with the construction of the SFD. 
These calculations assume no mitigation and that all animals observed 
would enter a given Level B harassment zone during pile driving.

          Table 8--Summary of CIBWs Sighting Data From April-November 2005-2009 and April-November 2020
----------------------------------------------------------------------------------------------------------------
                      Month                         Total hours    Total groups    Total whales     Whales/hour
----------------------------------------------------------------------------------------------------------------
April...........................................           52.50              13              35            0.67
May.............................................          457.40              53             208            0.45
June............................................          597.77              37             122            0.20
July............................................          552.67              14              27            0.05
August..........................................          577.30             120             543            0.94
September.......................................          533.03             124             445            0.83
October.........................................          450.70               9              22            0.05
November........................................          346.63              52             272            0.78
----------------------------------------------------------------------------------------------------------------
Data compiled from Kendall and Cornick (2015) and (61 North Environmental, 2021).

    To more accurately estimate potential exposures than simply using 
the monthly sighting rate data, which does not account for any 
mitigation, POA followed methods described by NMFS for the PCT Final 
IHA (85 FR 19294), which looked at previous monitoring results at the 
POA in relation to authorized take numbers. Between 2008 and 2012, NMFS 
authorized 34 CIBW takes per year to POA, with mitigation measures 
similar to the measures proposed here. The percent of the authorized 
takes documented during this time period ranged from 12 to 59 percent 
with an average of 36 percent (Table 9). In 2020, NMFS authorized 55 
CIBW takes in Phase 1 of the PCT project, with mitigation and 
monitoring measures that are consistent with those proposed for the SFD 
and described below in the Proposed Mitigation section. The percent of 
the authorized takes that were documented was 47 percent (26 out of 55 
exposures; 61 North Environmental, 2021; Table 9). Given that there was 
extensive monitoring occurring across all IHAs (with effort intensified 
in 2020), we

[[Page 31893]]

believe there is little potential that animals were taken but not 
observed.

            Table 9--Authorized and Reported CIBW Takes During POA Activities From 2009-2012 and 2020
----------------------------------------------------------------------------------------------------------------
                                                                                                    Percent of
                       ITA effective dates                        Reported takes    Authorized      authorized
                                                                                       takes           takes
----------------------------------------------------------------------------------------------------------------
15 July 2008-14 July 2009.......................................              12              34              35
15 July 2009-14 July 2010.......................................              20              34              59
15 July 2010-14 July 2011.......................................              13              34              38
15 July 2011-14 July 2012.......................................               4              34              12
1 April 2020-31 March 2021......................................              26              55              47
----------------------------------------------------------------------------------------------------------------

    As described in the POA's application and in more detail in the 
Proposed Mitigation section, mitigation measures have been designed to 
reduce Level B harassment take as well avoid Level A harassment take. 
We recognize that in certain situations, pile driving may not be able 
to be shut down prior to whales entering the Level B harassment zone 
due to safety concerns. During previous monitoring, sometimes CIBWs 
were initially sighted outside of the harassment zone and shutdown was 
called, but the CIBWs swam into the harassment zone before activities 
could be halted, and exposure within the harassment zone occurred. For 
example, on September 14, 2009, a construction observer sighted a CIBW 
just outside the harassment zone, moving quickly towards the 1,300 m 
Level B harassment zone during vibratory pile driving. The animal 
entered the harassment zone before construction activity could be shut 
down (ICRC, 2010). On other occasions, CIBWs were initially observed 
when they surfaced within the harassment zone. For example, on November 
4, 2009, 15 CIBWs were initially sighted approximately 950 m north of 
the project site near the shore, and then they surfaced in the Level B 
harassment zone during vibratory pile driving (ICRC, 2010). 
Construction activities were immediately shut down, but the 15 CIBWs 
were nevertheless exposed within the Level B harassment zone. During 
Phase 1 of the PCT project all of the recorded takes (n = 26) were 
instances where the whales were first sighted within the Level B 
harassment zone, prompting shutdown procedures. Most of these exposures 
(21 of 26) occurred when the CIBWs first appeared near the northern 
station, just south of Cairn Point (61 North Environmental, 2021). For 
example, on November 21, 2020 one CIBW was sighted in front of the 
north PSO station, located just south of Cairn Point, traveling south 
during vibratory removal of an attenuated 36-inch pile and a shutdown 
was called immediately (61 North Environmental, 2021). In 2020, the 
northern station did not have visibility of the near shoreline north of 
Cairn Point. As a result, CIBWs traveling south during ebb tides around 
Cairn Point were often inside of the Level B harassment zone upon first 
sighting (61 North Environmental, 2021). As described below in the 
Proposed Monitoring and Reporting section, mitigation and monitoring 
approaches for the SFD project are modeled after the stipulations 
outlined in the Final IHAs for Phase 1 and Phase 2 PCT construction (85 
FR 19294), but one of the PSO stations will be moved to enhance 
visibility to the north, especially near Cairn point. Therefore, we 
believe the ability to detect whales and shut down prior to them 
entering the Level B harassment zones will be better or consistent with 
previous years.
    To account for these mitigation measures, the POA then applied the 
highest percentage of previous takes (59 percent) to ensure potential 
impacts to CIBWs are adequately evaluated. After applying this 
adjustment to account for potential exposures of CIBWs that would be 
avoided by shutting down, the POA estimated that 12 CIBWs (20 whales * 
0.59 = 11.80 whales; 12 rounded up) may be exposed to Level B 
harassment during pile installation and removal. The POA and NMFS are 
concerned, however, that this approach does not accurately reflect the 
reality that CIBWs can travel in large groups. Large groups of CIBWs 
have been seen swimming through the POA vicinity during POA monitoring 
efforts. For example, during Phase 1 of the PCT, the mean group size 
was 4.34 whales; however, 52 percent of observations were of groups 
greater than the mean group size, with 5 percent of those 119 groups 
being larger than 12 individuals, the number of exposures proposed by 
POA (61 North Environmental, 2021).
    To ensure that a large group of CIBWs would not result in the POA 
using the majority or all of their take in one or two sightings, POA 
buffered the exposure estimate detailed in the preceding by adding the 
estimated size of a notional large group of CIBWs. The 95th percentile 
is commonly used in statistics to evaluate risk. Therefore, to 
determine the most appropriate size of a large group, the POA 
calculated the 95 percentile group size of CIBWs observed during 
Kendall and Cornick (2015) and 2020 Phase 1 PCT construction monitoring 
(61 North Environmental, 2021); the same data used above to derive 
hourly sighting rates (Table 8 and Figure 3). In this case, the 95th 
percentile provides a conservative value that reduces the risk to the 
POA of taking a large group of CIBWs and exceeding authorized take 
levels. The 95th percentile of group size for the Kendall and Cornick 
(2015) and the PCT Phase 1 monitoring data (61 North Environmental, 
2021) is 12.0. This means that, of the 422 documented CIBW groups in 
these data sets, 95 percent consisted of fewer than 12.0 whales; 5 
percent of the groups consisted of more than 12.0. Considering large 
group size, the POA requests and we propose to authorize 24 takes 
(accounting for the 12 takes calculated following the methods outlined 
for the PCT project that accounts for mitigation plus a group size of 
12) of CIBWs incidental to pile driving for the SFD. Incorporation of 
large groups into the CIBW exposure estimate is intended to reduce risk 
to the POA of the unintentional take of a larger number of belugas than 
would be authorized by using the proposed methods alone and thus 
improve our estimate of exposure. No Level A harassment is expected or 
proposed given the small Level A harassment zones for CIBWs (Table 7) 
and the additional mitigation measures described in the Proposed 
Mitigation section below specific to CIBWs, including the measure that 
pile driving activities must shut down when any CIBW enters the 
relevant Level B harassment zone.

[[Page 31894]]

[GRAPHIC] [TIFF OMITTED] TN15JN21.015

    In summary, the total amount of Level A harassment and Level B 
harassment proposed to be authorized for each marine mammal stock is 
presented in Table 10.

                         Table 10--Proposed Amount of Take, by Stock and Harassment Type
----------------------------------------------------------------------------------------------------------------
                                                                     Proposed authorized take
                Species                           Stock          --------------------------------   Percent of
                                                                      Level A         Level B          stock
----------------------------------------------------------------------------------------------------------------
Humpback whale........................  Western N Pacific.......               0               2            0.19
Beluga whale..........................  Cook Inlet..............               0              24            8.60
Killer whale..........................  Transient/Alaska                       0               6       1.02/0.26
                                         Resident.
Harbor porpoise.......................  Gulf of Alaska..........               0              12            0.04
Steller sea lion......................  Western.................               2               2           <0.01
Harbor seal...........................  Cook Inlet/Shelikof.....               2              19            0.07
----------------------------------------------------------------------------------------------------------------

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 (latter not applicable for this action). 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. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned), the likelihood of effective implementation (probability 
implemented as planned); and
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.
    The POA presented mitigation measures in Section 11 of their

[[Page 31895]]

application that were modeled after the stipulations outlined in the 
Final IHAs for Phase 1 and Phase 2 PCT construction (85 FR 19294), 
which were successful in minimizing the total number and duration of 
Level B harassment exposures for endangered CIBWs during Phase 1 PCT 
Construction (61 North Environmental, 2021). These measures both reduce 
noise into the aquatic environment and reduce the potential for CIBWs 
to be adversely impacted from any unavoidable noise exposure.
    A key mitigation measure NMFS considered for this project is 
reducing noise levels propagating into the environment. The POA will 
deploy an unconfined bubble curtain system during installation and 
removal of plumb (vertical) 24- and 36-inch piles with a vibratory or 
impact hammer. An unconfined bubble curtain is composed of an air 
compressor(s), supply lines to deliver the air, distribution manifolds 
or headers, perforated aeration pipe, and a frame. The frame 
facilitates transport and placement of the system, keeps the aeration 
pipes stable, and provides ballast to counteract the buoyancy of the 
aeration pipes in operation. The air is released through a series of 
vertically distributed bubble rings that create a cloud of bubbles that 
act to impede and scatter sound, lowering the sound velocity. A 
compressor provides a continuous supply of compressed air, which is 
distributed among the layered bubble rings. Air is released from small 
holes in the bubble rings to create a curtain of air bubbles 
surrounding the pile. The curtain of air bubbles floating to the 
surface inhibits the transmission of pile installation sounds into the 
surrounding water column. The final design of the bubble curtain will 
be determined by the Construction Contractor based on factors such as 
water depth, current velocities, and pile sizes. However, the proposed 
IHA requires the bubble curtain be operated in a manner consistent with 
the following performance standards:
     The aeration pipe system will consist of multiple layers 
of perforated pipe rings, stacked vertically in accordance with the 
following depths: Two layers for water depths <5 m; four layers for 
water depths 5 m to <10 m; seven layers for water depths 10 m to <15 m; 
ten layers for water depths 15 m to <20 m; and thirteen layers for 
water depths 20 m to <25 m;
     The pipes in all layers will be arranged in a geometric 
pattern that will allow for the pile being driven to be completely 
enclosed by bubbles for the full depth of the water column and with a 
radial dimension such that the rings are no more than 0.5 m from the 
outside surface of the pile;
     The lowest layer of perforated aeration pipe will be 
designed to ensure contact with the substrate without burial and will 
accommodate sloped conditions;
     Air holes will be 1.6 millimeters (\1/16\ inch) in 
diameter and will be spaced approximately 20 millimeters (\3/4\ inch) 
apart. Air holes with this size and spacing will be placed in four 
adjacent rows along the pipe to provide uniform bubble flux;
     The system will provide a bubble flux of 3 cubic meters 
(m\3\) per minute per linear meter of pipe in each layer (32.91 cubic 
feet (ft\3\) per minute per linear foot of pipe in each layer). The 
total volume of air per layer is the product of the bubble flux and the 
circumference of the ring using the formula: Vt = 3.0 m\3\/min/m * 
Circumference of the aeration ring in meters or Vt = 32.91 ft\3\/min/ft 
* Circumference of the aeration ring in feet; and
     Meters must be provided as follows:
    [cir] Pressure meters must be installed at all inlets to aeration 
pipelines and at points of lowest pressure in each branch of the 
aeration pipeline;
    [cir] Flow meters must be installed in the main line at each 
compressor and at each branch of the aeration pipelines at each inlet. 
In applications where the feed line from the compressor is continuous 
from the compressor to the aeration pipe inlet, the flow meter at the 
compressor can be eliminated; and
    [cir] Flow meters must be installed according to the manufacturer's 
recommendation based on either laminar flow or non-laminar flow.
    The bubble curtain will be used during installation and removal of 
all plumb piles when water depth is great enough (approximately 3 m) to 
deploy the bubble curtain. A bubble curtain will not be used with the 
two battered piles due to the angle of installation. It is important to 
note that a small number of piles could be installed or removed when 
the pile location is de-watered (no water present) or when the water is 
too shallow (<=3 m) to deploy the bubble curtain. The tides at the POA 
have a mean range of about 8.0 m (26 ft) (NOAA, 2015), and low water 
levels will prevent proper deployment and function of the bubble 
curtain system. Piles that are driven at a location that is de-watered 
will not use a bubble curtain, and marine mammal harassment zones will 
not be monitored. When piles are installed or removed in water without 
a bubble curtain because the pile orientation is battered, or if water 
is too shallow (<=3 m) to deploy the bubble curtain, the unattenuated 
Level A and Level B harassment zones for that hammer type and pile size 
will be implemented.
    In addition to noise attenuation devices, POA and NMFS considered 
practicable work restrictions. Given the extensive Level B harassment 
zone generated from the installation of the two unattenuated battered 
piles, vibratory driving these large piles during peak CIBW season 
poses an amount of risk and uncertainty to the degree that it should be 
minimized. This August and September peak is confirmed through acoustic 
monitoring (Castellote et al., 2020) and Phase 1 PCT construction 
monitoring (61 North Environmental, 2021). Castellote et al. (2020) for 
example indicate CIBWs appeared concentrated in the upper inlet year-
round, but particularly feeding in river mouths from April-December, 
shifting their geographical foraging preferences from the Susitna River 
region towards Knik Arm in mid-August, and dispersing towards the mid 
inlet throughout the winter. Further, hourly sighting rates calculated 
from monitoring data from Kendall and Cornick (2015) and Phase 1 of the 
PCT (61 North Environmental, 2021) were highest in August and September 
(0.94 and 0.83, respectively; Table 8). Therefore, vibratory driving 
unattenuated battered piles (which have, by far, the largest Level B 
harassment zones) will not occur during August or September. Further, 
to minimize the potential for overlapping sound fields from multiple 
stressors, the POA will not simultaneously operate two vibratory 
hammers for either pile installation or removal. This measure is 
designed to reduce simultaneous in-water noise exposure. Because impact 
hammers will not likely be dropping at the same time, and to expedite 
construction of the project to minimize pile driving during peak CIBW 
abundance periods, NMFS is not proposing to restrict the operation of 
two impact hammers at the same time. Given the small size of the 
project and the plan to primarily drive hammers with a vibratory 
hammer, the POA has indicated that it is highly unlikely that an impact 
hammer and vibratory hammer or two impact hammers would operate 
simultaneously during the SFD project.
    Additional mitigation measures include the following, modeled after 
the stipulations outlined in the Final IHAs for Phase 1 and Phase 2 PCT 
construction (85 FR 19294):
    For in-water construction involving heavy machinery activities 
other than pile driving (e.g., use of barge-mounted

[[Page 31896]]

excavators), the POA will cease operations and reduce vessel speed to 
the minimum level required to maintain steerage and safe working 
conditions if a marine mammal approaches within 10 m of the equipment 
or vessel.
    POA must use soft start techniques when impact pile driving. Soft 
start requires contractors to provide an initial set of three strikes 
at reduced energy, followed by a thirty-second waiting period, then two 
subsequent reduced energy strike sets. A soft start must 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. Soft starts will not be used for vibratory pile 
installation and removal. PSOs shall begin observing for marine mammals 
30 minutes before ``soft start'' or in-water pile installation or 
removal begins.
    The POA will conduct briefings for construction supervisors and 
crews, the monitoring team, and POA staff prior to the start of all 
pile installation and removal, and when new personnel join the work in 
order to explain responsibilities, communication procedures, the marine 
mammal monitoring protocol, and operational procedures.
    The POA will employ PSOs per the Marine Mammal Monitoring Plan (see 
Appendix A in the POA's application).
    Marine mammal monitoring will take place from 30 minutes prior to 
initiation of pile installation and removal through 30 minutes post-
completion of pile installation and removal. The Level B harassment 
zone must be fully visible for 30 minutes before the zone can be 
considered clear. Pile driving will commence when observers have 
declared the shutdown zone clear of marine mammals or the mitigation 
measures developed specifically for CIBWs (below) are satisfied. In the 
event of a delay or shutdown of activity, marine mammal behavior will 
be monitored and documented until the marine mammals leave the shutdown 
zone of their own volition, at which point pile installation or removal 
will begin. Further, NMFS requires that if pile driving has ceased for 
more than 30 minutes within a day and monitoring is not occurring 
during this break, another 30-minute pre-pile driving observation 
period is required before pile driving may commence.
    If a marine mammal is entering or is observed within an established 
Level A harassment zone or shutdown zone, pile installation and removal 
will be halted or delayed. Pile driving will not commence or resume 
until either the animal has voluntarily left and been visually 
confirmed 100 m beyond the shutdown zone and on a path away from such 
zone, or 15 minutes (non- CIBWs) or 30 minutes (CIBWs) have passed 
without subsequent detections.
    If a species for which authorization has not been granted, or a 
species for which authorization has been granted but the authorized 
takes are met, is observed approaching or within the Level B harassment 
zone, pile installation and removal will shut down immediately. Pile 
driving will not resume until the animal has been confirmed to have 
left the area or the 30 minute observation period has elapsed.
    In addition to these measures which greatly reduce the potential 
for harassment of all marine mammals and establish shutdown zones that 
realistically reflect non-CIBW whale detectability, the following 
additional mitigation measures have been proposed which would ensure 
valuable protection and conservation of CIBWs:
    Prior to the onset of pile driving, should a CIBW be observed 
approaching the mouth of Knik Arm, pile driving will be delayed. An in-
bound pre-clearance line extends from Point Woronzof to approximately 
2.5 kms west of Point McKenzie. Pile driving may commence once the 
whale(s) moves at least 100 m past the Level B harassment zone or pre-
clearance zone (whichever is larger) and on a path away from the zone. 
A similar pre-pile driving clearance zone will be established to the 
north of the POA (from Cairn Point to the opposite bank), allowing 
whales to leave Knik Arm undisturbed. Similar to the in-bound whale 
clearance zone, pile driving may not commence until a whale(s) moves at 
least 100 m past the Level B harassment zone or pre-clearance zone 
(whichever is larger) and on a path away from the zone. If non-CIBW 
whale species are observed within or likely to enter the Level B 
harassment zone prior to pile driving, the POA may commence pile 
driving but only if those animals are outside the 100 m shutdown zone 
and Level B harassment takes have not been exceeded.
    If pile installation or removal has commenced, and a CIBW(s) is 
observed within or likely to enter the Level B harassment zone, pile 
installation or removal will shut down and not re-commence until the 
whale has traveled at least 100 m beyond the Level B harassment zone 
and is on a path away from such zone or until no CIBW has been observed 
in the Level B harassment zone for 30 minutes.
    There may be situations where it is not possible to monitor the 
entire Level B harassment zone (e.g., during vibratory hammering of two 
unattenuated battered piles). In these cases, the pre-clearance zone 
remains applicable.
    If during installation and removal of piles, PSOs can no longer 
effectively monitor the entirety of the CIBW Level B harassment zone 
due to environmental conditions (e.g., fog, rain, wind), pile driving 
may continue only until the current segment of pile is driven; no 
additional sections of pile or additional piles may be driven until 
conditions improve such that the Level B harassment zone can be 
effectively monitored. If the Level B harassment zone cannot be 
monitored for more than 15 minutes, the entire Level B harassment zone 
will be cleared again for 30 minutes prior to pile driving.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

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

[[Page 31897]]

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.
    The POA will implement a marine mammal monitoring and mitigation 
strategy intended to avoid and minimize impacts to marine mammals (see 
Appendix A in the POA's application). The marine mammal monitoring and 
mitigation program that is planned for SFD construction will be modeled 
after the stipulations outlined in the Final IHAs for Phase 1 and Phase 
2 PCT construction (85 FR 19294). The POA will collect electronic data 
on marine mammal sightings and any behavioral responses to in-water 
pile installation or removal for species observed during pile 
installation and removal associated with the SFD Project. Four PSO 
teams will work concurrently to provide full coverage for marine mammal 
monitoring in rotating shifts during in-water pile installation and 
removal. All PSOs will be trained in marine mammal identification and 
behaviors. NMFS will review submitted PSO CVs and indicate approval as 
warranted.
    All PSOs will also undergo project-specific training, which will 
include training in monitoring, data collection, theodolite operation, 
and mitigation procedures specific to the SFD Project. This training 
will also include site-specific health and safety procedures, 
communication protocols, and supplemental training in marine mammal 
identification and data collection specific to the SFD Project. 
Training will include hands-on use of required field equipment to 
ensure that all equipment is working and PSOs know how to use the 
equipment.
    The POA proposes that eleven PSOs will be distributed at four 
stations: Anchorage Downtown Viewpoint near Point Woronzof, the 
Anchorage Public Boat Dock at Ship Creek, the SFD Project site, and the 
north end of POA property. These locations were chosen to maximize CIBW 
detection outside of Knik Arm and the mouth of Knik Arm. Specifically, 
PSOs at Port Woronzof will have unencumbered views of the entrance to 
Knik Arm and can provide information on CIBW group dynamics (e.g., 
group size, demographics, etc.) and behavior of animals approaching 
Knik Arm in the absence of and during pile driving. During the time 
since the POA submitted their final application, observers for the 2020 
PCT Phase 1 project have recommended, and NMFS has included in the 
proposed IHA, that the Ship Creek station be moved about 40 m to the 
end of the promontory to enhance visibility to the north, especially 
near Cairn point. The POA also considered moving a station from the POA 
property to Port MacKenzie for an improved view of CIBWs moving from 
north to south within Knik Arm. However, Port MacKenzie is not an 
available option due to logistical reasons; therefore, the northern 
station will remain located on POA property.
    Each of the PSO stations will be outfitted with a cargo container 
with an observation platform constructed on top. This additional 
elevation provides better viewing conditions for seeing distant marine 
mammals than from ground level and provides the PSOs with protection 
from weather. At least two PSOs will be on watch at any given time at 
each station; one PSO will be observing, one PSO will be recording data 
(and observing when there are no data to record). The station at the 
SFD site will have at least two PSOs. The northern and southern 
observations stations will have PSOs who will work in three- to four-
person teams. Teams of three will include one PSO who will be 
observing, one PSO who will be recording data (and observing when there 
are no data to record), and one PSO who will be resting. When 
available, a fourth PSO will assist with scanning, increasing scan 
intensity and the likelihood of detecting marine mammals. PSOs will 
work on a 60 minute rotation cycle and may observe for no more than 4 
hours at time and no more than 12 hours per day. In addition, if POA is 
conducting non-PCT-related in-water work that includes PSOs, the PCT 
PSOs must be in real-time contact with those PSOs, and both sets of 
PSOs must share all information regarding marine mammal sightings with 
each other.
    Trained PSOs will have no other construction-related tasks or 
responsibilities while conducting monitoring for marine mammals. 
Observations will be carried out using combinations of equipment that 
include 7 by 50 binoculars, 20x/40x tripod mounted binoculars, 25 by 
150 ``big eye'' tripod mounted binoculars (North End, Ship Creek, and 
Woronzof), and theodolites. PSOs will be responsible for monitoring the 
100 m shutdown zone, the Level A harassment zones, the Level B 
harassment zones, and the pre-clearance zones, as well as effectively 
documenting Level A and Level B harassment take. They will also (1) 
report on the frequency at which marine mammals are present in the 
project area, (2) report on behavior and group composition near the 
POA, (3) record all construction activities, and (4) report on observed 
reactions (changes in behavior or movement) of marine mammals during 
each sighting. Observers will monitor for marine mammals during all in-
water pile installation and removal associated with the SFD Project. 
Once pile installation and removal are completed for the day, marine 
mammal observations will continue for 30 minutes. Observers will work 
in collaboration with the POA to immediately communicate the presence 
of marine mammals prior to or during pile installation or removal.
    A draft report, including all electronic data collected and 
summarized from all monitoring locations, must be submitted to NMFS' 
MMPA program within 90 days of the completion of monitoring efforts. 
The report must include: Dates and times (begin and end) of all marine 
mammal monitoring; a description of daily construction activities, 
weather parameters and water conditions during each monitoring period; 
number of marine mammals observed, by species, distances and bearings 
of each marine mammal observed to the pile being driven or removed, age 
and sex class, if possible; number of individuals of each species 
(differentiated by month as appropriate) detected within the Level A 
harassment zones, the Level B harassment zones, and the shutdown zones, 
and estimates of number of marine mammals taken, by species (a 
correction factor may be applied); description of mitigation 
implemented, and description of attempts to distinguish between the 
number of individual animals taken and the number of incidences of 
take. A final marine mammal monitoring report will be prepared and 
submitted to NMFS within 30 days following receipt of comments on the 
draft report from NMFS.

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

[[Page 31898]]

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' 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 discussion of our analyses applies to all 
the species listed in Table 10 for which we authorized take, other than 
CIBWs, as the anticipated effects the POAs activities on marine mammals 
are expected to be relatively similar in nature. For CIBWs, there are 
meaningful differences in anticipated individual responses to 
activities, impact of expected take on CIBWs, or impacts on habitat; 
therefore, we provide a supplemental analysis for CIBWs, independent of 
the other species for which we authorize take.
    NMFS has identified key factors which may be employed to assess the 
level of analysis necessary to conclude whether potential impacts 
associated with a specified activity should be considered negligible. 
These include (but are not limited to) the type and magnitude of 
taking, the amount and importance of the available habitat for the 
species or stock that is affected, the duration of the anticipated 
effect to the species or stock, and the status of the species or stock. 
The following factors support negligible impact determinations for the 
affected stocks of humpback whales, killer whales, harbor porpoise, 
harbor seals, and Steller sea lions. The potential effects of the 
proposed actions on these species are discussed above. Some of these 
factors also apply to CIBWs; however, a more detailed analysis for 
CIBWs is provided below.
     No takes by mortality or serious injury are anticipated or 
authorized;
     The number of total takes (by Level A and Level B 
harassment) are less than 2 percent of the best available abundance 
estimates for all stocks;
     Take would not occur in places and/or times where take 
would be more likely to accrue to impacts on reproduction or survival, 
such as within ESA-designated or proposed critical habitat, 
biologically important areas (BIA), or other habitats critical to 
recruitment or survival (e.g., rookery);
     Take would occur over a short timeframe (i.e., up to 21 
total hours spread over nine to 24 non-consecutive days), and would be 
limited to the short duration a marine mammal would likely be present 
within a Level B harassment zone during pile driving. This short 
timeframe minimizes the probability of multiple exposures on 
individuals, and any repeated exposures that do occur are not expected 
to occur on sequential days, decreasing the likelihood of physiological 
impacts caused by chronic stress or sustained energetic impacts that 
might affect survival or reproductive success;
     Any impacts to marine mammal habitat from pile driving 
(including to prey sources as well as acoustic habitat, e.g., from 
masking) are expected to be temporary and minimal; and
     Take would only occur within upper Cook Inlet--a limited, 
confined area of any given stock's home range.
    For CIBWs, we further discuss our negligible impact findings in the 
context of potential impacts to this endangered stock. As described in 
the Recovery Plan for the CIBW (NMFS, 2016a), NMFS determined the 
following physical or biological features are essential to the 
conservation of this species: (1) Intertidal and subtidal waters of 
Cook Inlet with depths less than 30 feet mean lower low water (9.1 m) 
and within 5 mi (8 km) of high and medium flow anadromous fish streams; 
(2) Primary prey species consisting of four species of Pacific salmon 
(Chinook, sockeye, chum, and coho), Pacific eulachon, Pacific cod, 
walleye pollock, saffron cod, and yellowfin sole, (3) Waters free of 
toxins or other agents of a type and amount harmful to CIBWs, (4) 
Unrestricted passage within or between the critical habitat areas, and 
(5) Waters with in-water noise below levels resulting in the 
abandonment of critical habitat areas by CIBWs. The SFD would not 
impact essential features 1-3 listed above. All construction would be 
done in a manner implementing best management practices to preserve 
water quality, and no work would occur around creek mouths or river 
systems leading to prey abundance reductions. In addition, no physical 
structures would restrict passage; however, impacts to the acoustic 
habitat are of concern. Previous marine mammal monitoring data at the 
POA demonstrate CIBWs indeed pass by the POA during pile driving (e.g., 
61 North Environmental, 2021). As described above, there was no 
significant difference in CIBW sighting rate with and in the absence of 
pile driving (Kendall and Cornick, 2015). However, CIBWs do swim faster 
and in tighter formation in the presence of pile driving (Kendall and 
Cornick, 2015).
    Previously there has been concern that exposure to pile driving at 
the POA could result in CIBWs avoiding Knik Arm and thereby not 
accessing the productive foraging grounds north of POA such as Eagle 
River flats based on the proposed project and mitigation measures--
thus, impacting essential feature number 5 above (85 FR 19294). 
Although the data previously presented demonstrate whales are not 
abandoning the area (i.e., no significant difference in sighting rate 
with and without pile driving), results of a recent expert elicitation 
(EE) at a 2016 workshop, which predicted the impacts of noise on CIBW 
survival and reproduction given lost foraging opportunities, helped to 
inform our assessment of impacts on this stock. The 2016 EE workshop 
used conceptual models of an interim population consequences of 
disturbance (PCoD) for marine mammals (NRC, 2005; New et al., 2014, 
Tollit et al., 2016) to help in understanding how noise-related 
stressors might affect vital rates (survival, birth rate and growth) 
for CIBW (King et al., 2015). NMFS (2015, section IX.D--CI Beluga 
Hearing, Vocalization, and Noise Supplement) suggests that the main 
direct effects of noise on CIBW are likely to be through masking of 
vocalizations used for communication and prey location and habitat 
degradation. The 2016 workshop on CIBWs was specifically designed to 
provide regulators with a tool to help understand whether chronic and 
acute anthropogenic noise from various sources and projects are likely 
to be limiting recovery of the CIBW population. The full report can be 
found at https://www.smruconsulting.com/publications/ with a summary of 
the expert elicitation portion of the workshop below.
    For each of the noise effect mechanisms chosen for expert 
elicitation, the experts provided a set of

[[Page 31899]]

parameters and values that determined the forms of a relationship 
between the number of days of disturbance a female CIBW experiences in 
a particular period and the effect of that disturbance on her energy 
reserves. Examples included the number of days of disturbance during 
the period April, May, and June that would be predicted to reduce the 
energy reserves of a pregnant CIBW to such a level that she is certain 
to terminate the pregnancy or abandon the calf soon after birth, the 
number of days of disturbance in the period April-September required to 
reduce the energy reserves of a lactating CIBW to a level where she is 
certain to abandon her calf, and the number of days of disturbance 
where a female fails to gain sufficient energy by the end of summer to 
maintain themselves and their calves during the subsequent winter. 
Overall, median values ranged from 16 to 69 days of disturbance 
depending on the question. However, for this elicitation, a ``day of 
disturbance'' was defined as any day on which an animal loses the 
ability to forage for at least one tidal cycle (i.e., it forgoes 50-100 
percent of its energy intake on that day). The day of disturbance 
considered in the context of the report is notably more severe than the 
Level B harassment expected to result from these activities, which as 
described is expected be comprised predominantly of temporary 
modifications in the behavior of individual CIBWs (e.g., faster swim 
speeds, more cohesive group structure, avoidance, and increased 
foraging). Also, NMFS anticipates and has proposed to authorized 24 
instances of takes, with the instances representing disturbance events 
within a day--this means that either 24 different individual beluga 
whales are disturbed on no more than one day each, or some lesser 
number of individuals may be disturbed on more than one day, but with 
the product of individuals and days not exceeding 24. Given the overall 
anticipated take, it is very unlikely that any one beluga would be 
disturbed on more than a few days. Further, the mitigation measures 
NMFS has prescribed for the SFD project are designed to avoid the 
potential that any animal would lose the ability to forage for one or 
more tidal cycles. While Level B harassment (behavioral disturbance) is 
authorized, our mitigation measures would limit the severity of the 
effects of that Level B harassment to behavioral changes such as 
increased swim speeds, tighter group formations, and cessation of 
vocalizations, not the loss of foraging capabilities. Regardless, this 
elicitation recognized that pregnant or lactating females and calves 
are inherently more at risk than other animals, such as males. NMFS 
first considered proposing the POA shutdown based on more vulnerable 
life stages (e.g., calf presence) but ultimately determined all CIBWs 
warranted pile driving shutdown to be protective of potential 
vulnerable life stages, such as pregnancy, that could not be determined 
from observations, and to avoid more severe behavioral reaction.
    Monitoring data from the POA suggest pile driving does not 
discourage CIBWs from entering Knik Arm and travelling to critical 
foraging grounds such as those around Eagle Bay. As previously 
described, sighting rates were not different in the presence or absence 
of pile driving (Kendall and Cornick, 2015). In addition, CIBWs 
continued to use Knik Arm in 2020 during the duration of the PCT Phase 
1 construction project (61 North Environmental, 2021). These findings 
are not surprising as food is a strong motivation for marine mammals. 
As described in Forney et al. (2017), animals typically favor 
particular areas because of their importance for survival (e.g., 
feeding or breeding), and leaving may have significant costs to fitness 
(reduced foraging success, increased predation risk, increased exposure 
to other anthropogenic threats). Consequently, animals may be highly 
motivated to maintain foraging behavior in historical foraging areas 
despite negative impacts (e.g., Rolland et al., 2012). Previous 
monitoring data indicates CIBWs are responding to pile driving noise, 
but not through abandonment of critical habitat, including primary 
foraging areas north of the port. Instead, they travel faster past the 
POA, more quietly, and in tighter groups (which may be linked to the 
decreased communication patterns). During PCT Phase 1 construction 
monitoring, no definitive behavioral reactions to the in-water activity 
or avoidance behaviors were documented in CIBW. Little variability was 
evident in CIBW behaviors recorded by PSOs from month to month, or 
between sightings that coincided with in-water pile installation or 
removal and those that did not (61 North Environmental, 2021). Of the 
245 CIBWs groups sighted during PCT Phase 1 construction monitoring, 
seven groups were observed during or within minutes of in-water impact 
pile installation and 37 groups were observed during or within minutes 
of vibratory pile installation or removal (61 North Environmental, 
2021). During impact installation, three of these groups of CIBWs 
showed no reaction, three showed a potential reaction, and one group 
continued moving towards impact pile installation. Of the 37 vibratory 
events monitored, nine groups of CIBWs displayed a potential reaction, 
16 displayed no reaction, and 12 continued a trajectory towards the PCT 
(61N Environmental 2021). In general, CIBWs were more likely to display 
no reaction or to continue to move towards the PCT during pile 
installation and removal. In the situations during which CIBWs showed a 
possible reaction (three groups during impact driving and nine groups 
during vibratory driving), CIBWs were observed either moving away 
immediately after the pile driving activities started or observed 
increasing their rate of travel. This traveling behavior past the POA 
has also been verified by acoustic monitoring. Castellote et al. (2020) 
found low echolocation detection rates in lower Knik Arm indicating 
CIBWs moved through that area relatively quickly when entering or 
exiting the Arm. We anticipate that disturbance to CIBWs would manifest 
in the same manner when they are exposed to noise during the SFD 
project: Whales move quickly and silently through the area in more 
cohesive groups. We do not believe exposure to elevated noise levels 
during transit past the POA has adverse effects on reproduction or 
survival as the whales continue to access critical foraging grounds 
north of the POA, and tight associations help to mitigate the potential 
for any contraction of communication space for a group. We also do not 
anticipate that CIBWs will abandon entering or exiting Knik Arm, as 
this is not evident based on previous years of monitoring data (e.g., 
Kendall and Cornick 2015; 61N Environmental 2021), and the pre-pile 
driving clearance mitigation measure is designed to further avoid any 
potential abandonment. Finally, as described previously, both telemetry 
(tagging) and acoustic data suggest CIBWs likely stay in upper Knik Arm 
for several days or weeks before exiting Knik Arm. Specifically, a CIBW 
instrumented with a satellite link time/depth recorder entered Knik Arm 
on August 18th and remained in Eagle Bay until September 12th (Ferrero 
et al., 2000). Further, a recent detailed re-analysis of the satellite 
telemetry data confirms how several tagged whales exhibited this same 
movement pattern: Whales entered Knik Arm and remained there for 
several days before exiting through lower Knik Arm (Shelden et al., 
2018). This longer-term use of upper Knik Arm would avoid repetitive 
exposures from pile driving noise.

[[Page 31900]]

    POA proposed and NMFS has prescribed mitigation measures to 
minimize exposure to CIBWs, specifically, shutting down pile driving if 
CIBWs are observed approaching the mouth of Knik Arm, shutting down 
pile driving should a CIBW approach or enter the Level B harassment 
zone, stationing PSOs at Point Woronzof and Ship Creek, and not 
vibratory pile driving unattenuated battered piles during August or 
September (peak CIBW season). These measures are designed to ensure 
CIBWs will not abandon critical habitat and exposure to pile driving 
noise will not result in adverse impacts on the reproduction or 
survival of any individuals. The location of PSOs at Point Woronzof 
allows for detection of CIBWs and behavioral observations prior to 
CIBWs entering Knik Arm. Although NMFS does not anticipate CIBWs would 
abandon entering Knik Arm in the presence of pile driving with the 
required mitigation measures, these PSOs will be integral to 
identifying if CIBWs are potentially altering pathways they would 
otherwise take in the absence of pile driving. Finally, take by 
mortality, serious injury, or Level A harassment of CIBWs is not 
anticipated or authorized.
    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 CIBWs through 
effects on annual rates of recruitment or survival:
     No mortality is anticipated or authorized;
     Area of exposure would be limited to travel corridors. 
Data demonstrates Level B harassment manifests as increased swim speeds 
past the POA and tight group formations and not through habitat 
abandonment;
     No critical foraging grounds (e.g., Eagle Bay, Eagle 
River, Susitna Delta) would be impacted by pile driving; and
     While animals could be harassed more than once, exposures 
are not likely to exceed more than a few per year for any given 
individual and are not expected to occur on sequential days; thereby, 
decreasing the likelihood of physiological impacts caused by chronic 
stress or masking.
    We also considered our negligible impact analysis with respect to 
NMFS' technical report released in January 2020 regarding the abundance 
and status of CIBWs (Sheldon and Wade, 2019). As described in the 
marine mammal section, new analysis indicates the CIBW stock is smaller 
and declining faster than previously recognized. While this is 
concerning, NMFS continues to believe the taking authorized (allowed 
for in the cases where shutdowns cannot occur in time to avoid Level B 
harassment take) will not impact the reproduction or survival of any 
individuals, much less the stock, and will thereby have a negligible 
impact. The monitoring measures (four stations each equipped with two 
PSOs simultaneously on watch at each station) are extensive, such that 
we find it unlikely whales would go undetected. The mitigation measures 
reduce noise entering the water column (a benefit for all marine 
mammals) through the use of an unconfined bubble curtain. Further, the 
exposure risk to CIBWs is greatly minimized through the incorporation 
of in-bound and out-bound whale pre-pile driving clearance zones. 
Finally, should pile driving be occurring at the same time a whale is 
detected, pile driving would shut down prior to its entering the Level 
B harassment zone. All these measures, as well as other required 
measures such as soft-starts, greatly reduce the risk of animals not 
accessing important foraging areas north of the POA, which could result 
in impacts to individual fitness or annual rates of recruitment or 
survival. For these reasons, the new status of CIBWs does not 
ultimately change our findings with respect to the specified 
activities.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity 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. For all stocks, the 
amount of taking is less than one-third of the best available 
population abundance estimate (in fact it is less than 9 percent for 
all stocks considered here; Table 10).
    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 a specified activity that is 
likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by either causing 
the marine mammals to abandon or avoid hunting areas, directly 
displacing subsistence users, or placing physical barriers between the 
marine mammals and the subsistence hunters. An ``unmitigable adverse 
impact'' can also results from a specified activity that cannot be 
sufficiently mitigated by other measures to increase the availability 
of marine mammals to allow subsistence needs to be met.
    No subsistence use of CIBWs occurs and subsistence harvest of other 
marine mammals in upper Cook Inlet is limited to harbor seals. Steller 
sea lions are rare in upper Cook Inlet; therefore, subsistence use of 
this species is not common. However, Steller sea lions are taken for 
subsistence use in lower Cook Inlet. In 2013 and 2014, the Alaska 
Department of Fish and Game conducted studies to document the harvest 
and use of wild resources by residents of four tribal communities in 
Cook Inlet: Tyonek, Nanwalek, Port Graham, and Seldovia (Jones and 
Kostick, 2016). Tyonek is the community in closest proximity to Knik 
Arm while the other communities are located lower in Cook Inlet. The 
only marine mammal species taken by the Tyonek community was harbor 
seals (from the McArthur River Flats north to the Beluga River (Jones 
et al., 2015) south of Knik Arm) while communities lower in the inlet 
relied on harbor seals, Steller sea lions and sea otters (we note the 
sea otter is under the jurisdiction of the USFWS; therefore, it is not 
a part of our analysis).

[[Page 31901]]

    The potential impacts from harassment on stocks that are harvested 
in Cook Inlet would be limited to minor behavioral changes (e.g., 
increased swim speeds, changes in dive time, temporary avoidance near 
the POA, etc.) within the vicinity of the POA. Some PTS may occur; 
however, the shift is likely to be slight due to the implementation of 
mitigation measures (e.g., shutdown zones) and the shift would be 
limited to lower pile driving frequencies which are on the lower end of 
phocid and otariid hearing ranges. In summary, any impacts to harbor 
seals would be limited to those seals within Knik Arm (outside of any 
hunting area) and the very few takes of Steller sea lions in Knik Arm 
would be far removed in time and space from any hunting in lower Cook 
Inlet.
    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 the POA's 
proposed activities.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species, in this case with the Alaska Region 
Protected Resources Division Office.
    NMFS is proposing to authorize take of CIBWs, humpback whales from 
the Mexico DPS stock or Western North Pacific Stock, and Steller sea 
lions from the western DPS, which are listed under the ESA. The Permit 
and Conservation Division has requested initiation of Section 7 
consultation with the Alaska Region Protected Resources Division Office 
for the issuance of this IHA. NMFS will conclude the ESA consultation 
prior to reaching a determination regarding the proposed issuance of 
the authorization.

Proposed Authorization

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

    Dated: June 10, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-12551 Filed 6-14-21; 8:45 am]
BILLING CODE 3510-22-P