[Federal Register Volume 89, Number 208 (Monday, October 28, 2024)]
[Proposed Rules]
[Pages 85686-85747]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-24580]



[[Page 85685]]

Vol. 89

Monday,

No. 208

October 28, 2024

Part III





Department of Commerce





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National Oceanic and Atmospheric Administration





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50 CFR Part 217





Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to the Port of Alaska Modernization Program 
Phase 2B: Cargo Terminals Replacement Project in Anchorage, Alaska; 
Proposed Rule

Federal Register / Vol. 89, No. 208 / Monday, October 28, 2024 / 
Proposed Rules

[[Page 85686]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

50 CFR Part 217

[Docket No. 241018-0276]
RIN 0648-BM30


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Port of Alaska Modernization 
Program Phase 2B: Cargo Terminals Replacement Project in Anchorage, 
Alaska

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

ACTION: Proposed rule; request for comments.

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SUMMARY: NMFS received a request from the Don Young Port of Alaska 
(POA) for authorization to take marine mammals incidental to the Cargo 
Terminals Replacement Project at the existing port facility in 
Anchorage, Alaska over the course of 5 construction seasons (2026 
through 2030). Pursuant to the Marine Mammal Protection Act (MMPA), 
NMFS is proposing regulations setting forth permissible methods of 
taking, other means of effecting the least practicable adverse impact 
on such marine mammal stocks (i.e., mitigation measures), and 
requirements pertaining to monitoring and reporting such takes and 
requests comments on the proposed regulations. NMFS will consider 
public comments prior to making any final decision on the promulgation 
of the requested MMPA regulations, and NMFS's responses to public 
comments will be summarized in the final notification of our decision.

DATES: Comments and information must be received no later than November 
27, 2024.

ADDRESSES: A plain language summary of this proposed rule is available 
at https://www.regulations.gov/docket/NOAA-NMFS-2024-0030. You may 
submit comments on this document, identified by NOAA-NMFS-2024-0030, by 
the following method:
    <bullet> Electronic Submission: Submit all electronic public 
comments via the Federal e-Rulemaking Portal. Visit https://www.regulations.gov and type NOAA-NMFS-2024-0030 in the Search box. 
Click on the ``Comment'' icon, complete the required fields, and enter 
or attach your comments.
    Instructions: Comments sent by any other method, to any other 
address or individual, or received after the end of the comment period, 
may not be considered by NMFS. All comments received are a part of the 
public record and will generally be posted for public viewing on 
https://www.regulations.gov without change. All personal identifying 
information (e.g., name, address, etc.), confidential business 
information, or otherwise sensitive information submitted voluntarily 
by the sender will be publicly accessible. NMFS will accept anonymous 
comments (enter ``N/A'' in the required fields if you wish to remain 
anonymous).
    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/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization. In case of problems accessing these documents, please 
call the contact listed below.

FOR FURTHER INFORMATION CONTACT: Cara Hotchkin, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION: 

Purpose of Regulatory Action

    These proposed regulations, promulgated under the authority of the 
MMPA (16 U.S.C. 1361 et seq.), would provide a framework for 
authorizing the take of marine mammals incidental to construction 
activities associated with the POA's Modernization Program, including 
impact and vibratory pile driving.
    NMFS received an application from the POA requesting 5-year 
regulations and a letter of authorization issued thereunder to take 
individuals of seven species, comprising nine stocks of marine mammals 
by Level A harassment and Level B harassment incidental to the POA's 
activities. No serious injury or mortality is anticipated or proposed 
for authorization. Please see Background below for definitions of 
harassment.

Legal Authority for the Proposed Action

    Section 101(a)(5)(A) of the MMPA (16 U.S.C. 1371(a)(5)(A)) directs 
the Secretary of Commerce 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 for up to 5 years if, 
after notice and public comment, the agency makes certain findings and 
promulgates regulations that set forth permissible methods of taking 
pursuant to that activity and other means of effecting the ``least 
practicable adverse impact'' on the affected species or stocks and 
their habitat (see the discussion below in the Proposed Mitigation 
section), as well as monitoring and reporting requirements. Section 
101(a)(5)(A) of the MMPA and the implementing regulations at 50 CFR 
part 216, subpart I provide the legal basis for issuing this proposed 
rule containing 5-year regulations and for any subsequent Letters of 
Authorization (LOAs).

Summary of Major Provisions Within the Proposed Rule

    Following is a summary of the major provisions of this proposed 
rule regarding POA's activities. These measures include:
    <bullet> Prescribing permissible methods of taking of small numbers 
of marine mammals by Level A harassment and/or Level B harassment 
incidental to the Cargo Terminals Replacement Project;
    <bullet> Required monitoring of the construction areas to detect 
the presence of marine mammals before beginning construction 
activities;
    <bullet> Establishment of shutdown zones equivalent to the 
estimated Level B harassment zone for beluga whales;
    <bullet> Establishment of shutdown zones equivalent to or greater 
than the estimated Level A harassment zones for other species;
    <bullet> Bubble curtains required for all impact and vibratory 
driving of permanent (72-inch (in) (1.83 meter (m))) piles in more than 
3 m of water depth in all months and for vibratory driving of all 
temporary (24-in (0.61 m) or 36-in (0.91 m)) and permanent (72-in) 
piles between August and October;
    <bullet> Soft start for impact pile driving to allow marine mammals 
the opportunity to leave the area prior to beginning impact pile 
driving at full power; and
    <bullet> Submittal of monitoring reports including a summary of 
marine mammal species and behavioral observations, construction 
shutdowns or delays, and construction work completed.
    Through adaptive management, the proposed regulations would allow 
NMFS Office of Protected Resources to modify (e.g., remove, revise, or 
add to) the existing mitigation, monitoring, or reporting measures 
summarized above and required by the LOA.

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

[[Page 85687]]

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 promulgated or 
an incidental harassment authorization is issued.
    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). If such findings are made, NMFS must prescribe the 
permissible methods of taking and other ``means of effecting the least 
practicable adverse impact'' on the affected species or stocks and 
their habitat, paying particular attention to rookeries, mating 
grounds, and areas of similar significance, and on the availability of 
the species or stocks for taking for certain subsistence uses (referred 
to in shorthand as ``mitigation''); and requirements pertaining to the 
monitoring and reporting of the takings 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 evaluate our proposed action's (i.e., promulgation of 
regulations and subsequent issuance of a LOA thereunder) and 
alternatives to that action's potential impacts on the human 
environment.
    Accordingly, NMFS has prepared an Environmental Assessment (EA) to 
evaluate the environmental impacts associated with the issuance of the 
proposed regulations and LOA. NMFS' EA is available at https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization. We will 
review all comments submitted in response to this notice prior to 
concluding our NEPA process or making a final decision on this request.

Summary of Request

    On January 3, 2023, NMFS received a request from the POA for 
regulations and a subsequent LOA to take marine mammals incidental to 
construction activities related to the POA Modernization Program (PAMP) 
Phase 2B: Cargo Terminals Replacement (CTR) at the POA in Anchorage, 
Alaska. NMFS provided comments on the application on March 3, 2023, 
April 20, 2023, and May 18, 2023. After POA submitted a revised 
application on October 13, 2023, and responded to additional questions 
sent on December 20, 2023, we determined the application was adequate 
and complete on February 12, 2024.
    On March 4, 2024, we published a notice of receipt (NOR) of 
application in the Federal Register (89 FR 15548), requesting comments 
and information during a 30-day public comment period related to the 
POA's request. We received one comment letter from the Center for 
Biological Diversity. NMFS has reviewed all submitted material and 
taken the information into consideration during the drafting of this 
proposed rule.
    The POA's request is for take of seven species of marine mammals by 
Level B harassment and for a subset of these species, Level A 
harassment. Neither POA nor NMFS expect serious injury or mortality to 
result from the specified activities. If promulgated, the regulations 
would be effective for the first 5 construction seasons (2026-2030).
    NMFS previously issued IHAs to the POA for similar work (85 FR 
19294, April 6, 2020; 86 FR 50057, September 7, 2021; 89 FR 2832, 
January 14, 2024). The POA complied with all the requirements (e.g., 
mitigation, monitoring, and reporting) of the 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 of Marine Mammals sections of this proposed rule and 
online at https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

Description of the Specified Activities

Overview

    The POA, located on Knik Arm in upper Cook Inlet, provides critical 
infrastructure for the citizens of Anchorage and a majority of the 
citizens of Alaska. The POA was constructed primarily in the 1960s and 
is currently in poor condition and substantially past its initial 
design life. The existing cargo terminals T1, T2, and T3 are 
deteriorating and in poor structural condition and present safety and 
security concerns for human health and the economic stability of the 
state of Alaska. The PAMP is designed to replace the existing 
facilities with new infrastructure incorporating modern seismic codes 
over a 75-year design life. PAMP Phase 2B includes the demolition and 
replacement of terminals T1 and T2 and the partial demolition of T3. 
This phase is expected to take approximately 6 years of in-water work 
to complete. If promulgated, the regulations would be effective for the 
first 5 construction seasons (2026-2030).
    In-water pile installation will include both temporary (24-in (0.61 
m) or 36-in (0.91 m)) and permanent (72-in (1.83 m)) steel pipe piles 
by impact and vibratory hammers. Removal of temporary piles (24- or 35-
in) and existing structures (16-in (0.41 m) to 42-in (1.07 m) steel 
pipe piles) would be primarily by cutting; dead-pull and vibratory 
extraction methods may also be used. Existing piles may also be left 
standing in their current positions. In-water work associated with the 
project would include installation of approximately 275 permanent piles 
and 450 temporary piles and vibratory extraction of approximately 46 
temporary piles over the 5-year period.

Dates and Duration

    The POA anticipates that in-water construction activities 
associated with this proposed rule would begin on April 1, 2026 and 
extend through November 30, 2030. In-water pile installation and 
removal associated with the CTR project is anticipated to take place 
over approximately 689 hours on approximately 337 nonconsecutive days 
between the months of April and November over the 5 year period (see 
table 1 for estimated production rates and durations). While the exact 
sequence of demolition and construction is uncertain, an estimated 
schedule is shown in table 2. This schedule is based on best available 
information and is not intended to be a limitation on the number of 
pile installation or removal hours that may occur in any given month.
    The POA has presented the schedule shown in table 2 using the best 
available information derived from what is known of the existing Cargo 
Terminals site and the POA's experience with similar construction and 
demolition projects. A typical construction season at the POA extends 
from approximately mid-April to mid-October (6 months) and may include 
November. Exact dates of ice-out in the spring and formation of new ice 
in the fall vary from year to year and cannot be predicted with 
accuracy. In-water pile installation and removal cannot occur during 
the winter months when ice is present because of the hazards associated 
with moving ice floes that change directions four times a day, 
preventing the use of tugs, barges, workboats, and other vessels. Ice

[[Page 85688]]

movement also prevents accurate placement of piles.
    While the POA plans to conduct as much work as possible between 
April and July, when there is lower Cook Inlet beluga whale (CIBW; 
Delphinapterus leucas) abundance (see the Description of Marine Mammals 
in the Area of Specified Activities section for details on CIBW 
presence at the POA), front-loading of work is dependent on 
construction sequencing. Construction sequencing requires that 
temporary piles are installed as a template, then larger permanent 
piles are installed, and then the temporary piles are removed. This 
required sequence plays out many times, in this order, during the open 
water construction season. It is not possible to install all of the 
larger permanent piles during the early season and install temporary 
piles later in the season; the larger and smaller piles must be 
alternated. Exact project sequencing and installation and extraction 
methods are at the discretion of the construction crew. Construction 
dates may change because of unexpected project delays, ongoing 
construction activities in other areas of the POA, timing of ice-out 
and spring breakup, and other factors. Therefore, the estimated 
schedule (table 2) reflects a realistic scenario for the proposed 
project, but conditions on the ground may result in slight changes to 
this estimated schedule.

[[Page 85689]]



                                            Table 1--Pile Installation and Removal Methods, Estimated Amounts, and Estimated Durations for Years 1-5
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                                                                                                                    Average                                     Average
                                                                   Total      Estimated number  Average vibratory    impact    Estimated   Total duration of   production
            Activity type                 Pile size and type     estimated    of piles in the   duration per pile   duration     impact        removal or     rate, piles   Estimated number of
                                                                 number of       water \1\          (minutes)       per pile  strikes per   installation in     per day      days over 5 years
                                                                   piles                                           (minutes)      pile       water (hours)      (range)
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Temporary pile installation..........  24- or 36-in (61- or 91-         565                450                 30  .........  ...........          225 hours          2-4  144.
                                        cm) Steel pipe.
Temporary pile removal...............  24- or 36-in (61- or 91-         161                 46                 45  .........  ...........           35 hours          2-4  15.
                                        cm) Steel pipe.
Permanent pile installation..........  72-in (182-cm) Steel             310                275                 10         86        5,743          440 hours        0.5-3  159.
                                        pipe.
                                                               ---------------------------------------------------------------------------------------------------------------------------------
    Total............................  .......................        1,036                771  .................  .........  ...........          700 hours  ...........  337 days.
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Note: cm = centimeter(s); 1--Piles installed above the mean lower low water line are considered ``in the dry'' (i.e., not in-water). It is anticipated that the permanent and temporary piles in
  the three bents nearest the shore for all five trestles would be installed in the dry at low tide levels. An additional bent would be installed in the dry for the northernmost trestle of T1
  and for the three trestles of T2. These piles are not considered to have the potential for impact to marine mammals and are thus excluded from the following analyses.


                                           Table 2--Estimated Timing and Duration (in Hours per Month) of Pile Installation and Removal Activities \1\
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                                                                                                  Duration (hours of activity by month and year)
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                    Activity                             Apr               May               Jun               Jul               Aug               Sep               Oct               Nov
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
                                                  Imp \2\  Vib \3\    Imp      Vib      Imp      Vip      Imp      Vib      Imp      Vib      Imp      Vib      Imp      Vib      Imp      Vib
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                                                                                          Year 1--2026
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24- or 36-in Temporary Pile Installation........  .......      2.5  .......      6.0  .......      6.0  .......      6.0  .......      6.0  .......      6.0  .......      3.0  .......        2
24- or 36-in Temporary Pile Removal.............  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8
72-in Permanent Pile Installation \4\...........      7.2      0.8     15.8      1.8     15.8      1.8     15.8      1.8     12.9      1.5     12.9      1.5     12.9      1.5      5.7      0.7
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
    Year 1 total hours..........................      7.2      4.1     15.8      8.6     15.8      8.6     15.8      8.6     12.9      8.3     12.9      8.3     12.9      5.3      5.7      3.4
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                                                                                          Year 2--2027
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24- or 36-in Temporary Pile Installation........  .......      3.0  .......      5.0  .......      5.0  .......      5.0  .......      5.0  .......      5.0  .......      2.5  .......        2
24- or 36-in Temporary Pile Removal.............  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......  .......
72-in Permanent Pile Installation \4\...........      7.2      0.8     12.9      1.5     12.9      1.5     12.9      1.5     12.9      1.5     11.5      1.3     11.5      1.3      5.7      0.7
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
    Year 2 total hours..........................      7.2      4.6     12.9      7.3     12.9      7.3     12.9      7.3     12.9      7.3     11.5      7.1     11.5      4.6      5.7      2.7
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                                                                                          Year 3--2028
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24- or 36-in Temporary Pile Installation........  .......      6.5  .......     13.0  .......     13.0  .......     13.0  .......     13.0  .......     13.0  .......      6.5  .......        2
24- or 36-in Temporary Pile Removal.............  .......      0.8  .......      2.3  .......      2.3  .......      2.3  .......      1.5  .......      1.5  .......      0.8  .......      0.8
72-in Permanent Pile Installation \4\...........      5.7      0.7      5.7      0.7      5.7      0.7      4.3      0.5      4.3      0.5      4.3      0.5      4.3      0.5      4.3      0.5
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
    Year 3 total hours..........................      5.7      7.9      5.7     15.9      5.7     15.9      4.3     15.8      4.3     15.0      4.3     15.0      4.3      7.8      4.3      3.3
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                                                                                          Year 4--2029
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24- or 36-in Temporary Pile Installation........  .......      2.5  .......      5.5  .......      5.5  .......      6.0  .......      5.5  .......      5.5  .......      2.5  .......        2
24- or 36-in Temporary Pile Removal.............  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......      0.8  .......  .......
72-in Permanent Pile Installation \4\...........      7.2      0.8     12.9      1.5     12.9      1.5     12.9      1.5     12.9      1.5     11.5      1.3     11.5      1.3      5.7      0.7
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
    Year 4 total hours..........................      7.2      4.1     12.9      7.8     12.9      7.8     12.9      8.3     12.9      7.8     11.5      7.6     11.5      4.6      5.7      2.7
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                                                                                          Year 5--2030
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24- or 36-in Temporary Pile Installation........  .......      2.5  .......      6.0  .......      6.0  .......      6.0  .......      6.0  .......      5.5  .......      5.5  .......      2.5
24- or 36-in Temporary Pile Removal.............  .......      0.8  .......      0.8  .......      1.5  .......      1.5  .......      0.8  .......      0.8  .......      0.8  .......      0.8
72-in Permanent Pile Installation \4\...........      4.3      0.5     12.9      1.5     12.9      1.5     12.9      1.5     11.5      1.3     11.5      1.3     11.5      1.3      4.3      0.5
                                                 -----------------------------------------------------------------------------------------------------------------------------------------------
Year 5 total hours..............................      4.3      3.8     12.9      8.3     12.9      8.3     12.9      8.3     11.5      8.1     11.5      7.6     11.5      7.6      4.3      3.8
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\1\ Duration estimates assume a single hammer active at any time and therefore likely overestimates of actual time needed due to simultaneous pile installation and removal;
\2\ Impact pile installation;

[[Page 85690]]

 
\3\ Vibratory pile installation or extraction;
\4\ To account for piles driven in water less than 3m deep, NMFS has estimated approximately 0.5 unattenuated 72-in piles will be driven (approximately 43 minutes of impact driving and 5
  minutes of vibratory driving) each month. Numbers may not add exactly due to rounding.


[[Page 85691]]

Specific Geographic Region

    The specific geographic region for this action encompasses the land 
occupied by the POA, as well as the shoreline and waters extending from 
the POA across Knik Arm, northeast towards Wasilla, and southwest 
towards Fire Island and the Little Susitna River delta (figure 1).
    Northern Cook Inlet bifurcates into Knik Arm to the north and 
Turnagain Arm to the east. Knik Arm is generally considered to begin at 
Point Woronzof, 7.4 km southwest of the POA. From Point Woronzof, Knik 
Arm extends about 48 km 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 before widening to as much 
as 8 km at the tidal flats northwest of Eagle Bay at the mouth of Eagle 
River.
    Knik Arm comprises narrow channels flanked by large tidal flats 
composed of sand, mud, or gravel, depending upon location. 
Approximately 60 percent of Knik Arm is exposed at Mean Lower Low Water 
(MLLW). The intertidal (tidally influenced) areas of Knik Arm are 
mudflats, both vegetated and unvegetated, which consist primarily of 
fine, silt-sized glacial flour. Freshwater sources often are glacially 
born waters, which carry high suspended sediment loads as well as a 
variety of metals such as zinc, barium, mercury, and cadmium. Surface 
waters in Cook Inlet typically carry high silt and sediment loads, 
particularly during summer, making Knik Arm an extremely silty, turbid 
waterbody with low visibility through the water column. The Matanuska 
and Knik Rivers contribute the majority of freshwater and suspended 
sediment into Knik Arm during summer. Smaller rivers and creeks also 
enter along the sides of Knik Arm (U.S. Department of Transportation 
and Port of Anchorage, 2008). During winter, sea, beach, and river ice 
are dominant physical forces within Cook Inlet and Knik Arm. In upper 
Cook Inlet, sea ice generally forms in October to November and 
continues to develop through February or March (Moore et al., 2000).
    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 m, and the maximum water 
level has been measured at more than 12.5 m at the Anchorage station 
(NMFS, 2015). Currents throughout Cook Inlet are strong and tidally 
periodic, with average velocities ranging from 3 to 6 knots (5.6 to 
11.1 kilometers (km)/hour (h)) (Sharma and Burrell, 1970). Maximum 
current speeds in Knik Arm, observed during spring ebb tide, exceed 7 
knots (13 km/h). These tides result in strong currents in alternating 
directions through Knik Arm and a well-mixed water column. The 
navigation harbor at the POA is a dredged basin in the natural tidal 
flat. Sediment loads in upper Cook Inlet can be high; spring thaws 
occur, and accompanying river discharges introduce considerable amounts 
of sediment into the system (Ebersole and Raad, 2004). Natural 
sedimentation processes act to continuously infill the dredged basin 
each spring and summer.
    The Municipality of Anchorage is located in the lower reaches of 
Knik Arm of upper Cook Inlet (see figure 2-1 in the POA's application). 
The POA sits on the industrial waterfront of Anchorage, just south of 
Cairn Point and north of Ship Creek (lat. 61[deg]15' N, long. 
149[deg]52' W; Seward Meridian) (figure 1). The POA's boundaries 
currently occupy an area of approximately 0.52 km\2\ (figure 2). Other 
commercial and industrial activities related to secured maritime 
operations are located near the POA on Alaska Railroad Corporation 
property immediately south of the POA, on approximately 0.45 km\2\ at a 
similar elevation. The POA is located north of Ship Creek, an area that 
experiences concentrated marine mammal activity during seasonal runs of 
several salmon species. Ship Creek serves as an important recreational 
fishing resource and is stocked twice each summer. Ship Creek flows 
into Knik Arm through the Municipality of Anchorage industrial area. 
Joint Base Elmendorf-Richardson (JBER) is located east of the POA, 
approximately 30.5 m higher in elevation. The U.S. Army Defense Fuel 
Support Point-Anchorage site is located east of the POA, south of JBER, 
and north of Alaska Railroad Corporation property. The perpendicular 
distance to the west bank directly across Knik Arm from the POA is 
approximately 4.2 km. The distance from the POA (east side) to nearby 
Port MacKenzie (west side) is approximately 4.9 km.
BILLING CODE 3510-22-P

[[Page 85692]]

[GRAPHIC] [TIFF OMITTED] TP28OC24.002


[[Page 85693]]


[GRAPHIC] [TIFF OMITTED] TP28OC24.003

BILLING CODE 3510-22-C

Detailed Description of the Specified Activities

    As discussed previously, marine-side infrastructure and facilities 
at the POA are in need of replacement because they are substantially 
past their design life and in poor and deteriorating structural 
condition. Those facilities include three general cargo terminals, two 
petroleum terminals, a dry barge landing, and an upland sheet-pile-
supported storage and work area. To address deficiencies, the POA is 
modernizing its marine terminals through the PAMP to enable safe, 
reliable, and cost-effective Port operations. The PAMP will support 
infrastructure resilience in the event of

[[Page 85694]]

a catastrophic natural disaster over a 75-year design life.
    The PAMP is critical to maintaining food and fuel security for the 
state. At the completion of the PAMP, the POA will have modern, safe, 
resilient, and efficient facilities through which more than 90 percent 
of Alaskans will continue to obtain food, supplies, tools, vehicles, 
and fuel. The PAMP is divided into five separate phases; these phases 
are designed to include projects that have independent utility yet 
streamline agency permitting. The projects associated with the PAMP 
include:
    <bullet> Phase 1: Petroleum and Cement Terminal (PCT Phase 1 and 2) 
and South Floating Dock (SFD) replacement;
    <bullet> Phase 2A: North Extension Stabilization Phase 1 (NES1);
    <bullet> Phase 2B: CTR;
    <bullet> Phase 3: Petroleum, Oil and Lubricants Terminal 2 
Replacement;
    <bullet> Phase 4: North Extension Stabilization part 2; and
    <bullet> Phase 5: Demolition of Terminal 3.
    Phase 1 of the PAMP was completed in 2022. NMFS issued IHAs for 
take incidental to the now completed PCT (Phase 1 and Phase 2; 85 FR 
19294, April 6, 2020) and SFD projects (86 FR 50057, September 7, 
2021). Phase 2A of the PAMP began in 2023; an IHA was issued for phase 
one of the NES project (89 FR 2832, January 14, 2024) and in-water 
construction associated with this project is planned for 2024. The 
project discussed herein, CTR, is Phase 2B of the PAMP and is proposed 
to begin onshore preparation in 2025 and in-water construction work in 
2026.
    The purpose of the CTR project is to replace the existing general 
cargo docks. It would address deteriorating conditions of the existing 
cargo facilities; improve operational safety and efficiency; 
accommodate modern (existing and future) shipping operations; and 
improve the resiliency of the POA to extreme seismic events, all while 
sustaining ongoing cargo operations. This project is urgently needed 
due to severe corrosion of the foundation piles and deteriorating 
structural conditions at Terminals 1, 2, and 3. The existing terminals 
are more than 50 years old and suffer from severe damage to the 
foundation piles caused by corrosion and seismic forces. The piles have 
exceeded their useful service life, and multiple engineering 
investigations have highlighted the probability of wharf and trestle 
structure failure during a future major seismic event. The remaining 
service life of the cargo terminals is unknown. These facilities must 
be replaced with new resilient terminals for the Port to continue to 
meet its critical role serving Alaska's general cargo needs as well as 
supporting national defense and military readiness capabilities.
    The geographical isolation of Alaska and the POA's role as the 
containerized logistic hub and distribution center for much of the 
state make the cargo terminals a critical lifeline for the southcentral 
region and Alaska. There are no other ports with the cargo capacity, 
proximity to Alaska's population centers, and intermodal transportation 
capabilities that can support the logistic missions sustained by the 
POA, including commerce, national defense, and earthquake resiliency/
disaster response and recovery.

CTR Project Activities

    The CTR project includes construction of new terminals T1 and T2, 
which include planned wharves and access trestles. The two new 
terminals would be located 140 feet (ft) (42.7 meters (m)) seaward of 
the existing T1, T2, and T3. It is anticipated that this more seaward 
location of the new terminals will reduce sedimentation, improve room 
for handling of berthing ships, and allow construction of the new 
terminals while the existing terminals remain in use. CTR also includes 
demolition of the existing Petroleum, Oil, and Lubricants Terminal 1 
(POL1) and general cargo terminals (T1, T2, and T3).
    The southernmost end of the new T1 and T2 would be approximately 
1.4 km (0.9 mile (mi)) north of Ship Creek. Construction of the Project 
will include completion of the following components:
    <bullet> Component 1. Onshore ground improvement shoreline 
stabilization (2025)
    <bullet> Component 2. Shoreline expansion and protection (2026)
    <bullet> Component 3. General cargo terminals (new Terminals 1 and 
2) construction (2026-2031)
    <bullet> Component 4. Demolition of existing terminals (POL1 and 
general cargo terminals (existing Terminals 1, 2, and 3)) (2026-2031)
    <bullet> Component 5. Onshore utilities and storm drain outfall 
replacement (2030-2031)
    Of these activities, only Components 3 and 4 include construction 
work that would occur in the water, and therefore, these would be the 
only components of the project expected to potentially impact marine 
mammals.

Landside Activities

    Landside activities include work which takes place ``in the dry,'' 
either above the high tide line or in the intertidal zone but de-
watered. These activities include shoreline stabilization and 
protection as well as placement of onshore utilities and decking 
components.
    Ground Improvement Shoreline Stabilization--A ground improvement 
technique, such as deep soil mixing (DSM), or a similar technique would 
be used to stabilize the shoreline. DSM and similar techniques 
mechanically mix weak soils with a cement binder causing the soils to 
behave more like soft rock. This process is used to create foundations 
for buildings and roads and is used in earthquake-prone areas to 
prevent soil liquefaction. Soil improvements at trestle abutments, and 
potentially between the abutments, will mitigate the potential for 
seismic-induced slope failure that could result in catastrophic 
structural failure.
    The first stage of construction would include installation of soil 
improvements in the five locations where the access trestles meet the 
beach to provide geotechnical stability to the embankment. Centered at 
each of the five trestle abutments, the ground improvement technique 
would create approximately 200- by 96-ft (61- by 29-m) blocks of 
treated soil extending from the surface to the top of the clay layer 
approximately 85-ft (25.9-m) deep (see figure 1-2 of the POA's 
application). The size of the block is designed to create enough 
contact area with the clay layer to restrain and significantly reduce 
the overall ground movements of the liquefiable soils surrounding the 
trestle abutment. If deemed necessary for geotechnical stability, 
ground improvements would extend along the embankment in areas between 
the abutments.
    During construction, a temporary soil work pad would be constructed 
at each of the five trestles to provide a level temporary work surface. 
The ground improvement panels/columns would extend approximately 100 
feet (ft) (30.5-m) seaward and shoreward of the crest of the slope and 
approximately 30 ft (9-m) to either side of the trestle structure. 
Temporary armoring will protect the work pad from water forces while in 
use. After completion of the ground improvement work, the temporary 
construction work pads will be removed and the foreshore graded and 
armored.
    Shoreline Expansion and Protection--The existing shoreline behind 
the existing Terminals 1, 2, and 3 is irregular, with two areas where 
the shoreline is located about 100 ft (30-m) to the east of the typical 
shoreline (see figure 1-3 of the POA's application). These areas would 
be excavated to remove deposited silts before the areas

[[Page 85695]]

are then filled with more dense, stable materials such as clean gravel 
and rock. The filled area would provide a consistent shoreline and 
additional container storage area.
    Excavation for the CTR project would be limited to removal of 
materials that are above the high-water line or below the high-water 
line in a dewatered state. Sea-based dredging of materials under water 
will not take place as part of this project.
    After ground improvement work and shoreline expansion have been 
completed, the slope along the shore would be secured with armor stone 
placed over the clean gravel and rock fill. Placement of armor rock 
requires good visibility of the shore as each rock is placed carefully 
to interlock with surrounding armor rock. It is therefore anticipated 
that placement of most armor rock, filter rock, and granular fill will 
occur in the dry at low tide levels; however, some placement of armor 
rock, filter rock, and granular fill may occur in shallow water (i.e., 
less than 3 m deep). After placement of armor rock, the top of the fill 
will be paved to match the existing backland pavements.
    Onshore utilities and storm drain outfall replacement--The 
replacement of onshore utilities will involve construction on land and 
replacement of utilities above the high tide line, on land. Similarly, 
the storm drain outfall replacement will involve construction on land 
and replacement of four outfall pipes above the high tide line. No in-
water work is proposed as a part of this component.
    Ground improvement shoreline stabilization, shoreline expansion and 
protection, and onshore utilities and storm drain outfall replacement 
activities would take place on land or in the dry. While a minimal 
amount of fill and armor rock placement may occur in water, this 
activity would not be expected to impact marine mammals. Therefore, 
take of marine mammals related to these activities is not anticipated 
or proposed to be authorized, and it will not be considered further in 
this proposed rulemaking.

In-Water Construction

    New terminals T1 and T2 would be constructed as seismically 
resilient adjoining terminals on a continuous berthline with mooring 
features and appurtenances as required to support safe ship mooring for 
lift-on/lift-off and roll-on/roll-off related cargo handling 
operations. The new T1 wharf would be 870 ft x 120 ft (265- x 37-m) 
with two 36-ft-wide (11-m) trestles of varying length. The new T2 wharf 
would be 932 ft x 120 ft (284- x 37-m) with two 259-ft- long x 54-ft-
wide (79- x 16.5-m) trestles and one 259-ft-long x 76-ft-wide (79- x 
23-m) trestle. Both T1 and T2 would be constructed using 48- and 72-in-
diameter (121- and 183-centimeter (cm), respectively) steel piles. The 
48-in-diameter piles will be installed in the dry.
    Both new terminals would be designed to accommodate lift-on/lift-
off container operations serviced by rail-mounted ship-to-shore cranes. 
Structural, in-deck, and surface features to support operational 
interface for three 100-gauge rail mounted gantry cranes, and 
associated appurtenances along with an on-terminal combination 
stevedore-operations building, would be included on the wharf. 
Additionally, T2 would be designed to support roll-on/roll-off 
container operations and other multi-purpose cargo functions. The 
reinforced concrete deck structure for both new terminals and all new 
access trestles would be designed to 1,000 pound per square foot load 
capacity. Construction would also include installation of power, 
lighting, communications, and signal infrastructure to terminal and 
onshore electrically powered features; potable water service including 
ship's water; and fire-flow water for terminal-related operations. The 
on-terminal stevedore-operations building would also be constructed 
with a connection to the onshore, existing public utility 
infrastructure.
    In addition to these permanent structures, temporary work including 
temporary pile installation and removal would be required to support 
construction. Temporary piles would likely be 36-in-diameter (91-cm) 
steel; however, 24-in (61-cm) steel piles may be used in place of some 
of the larger temporary piles. Various work boats and barges would be 
utilized and would be moored at or in the immediate vicinity of the 
project, but these vessels are not expected to increase overall noise 
levels at the POA above existing operational levels. No thrusters or 
other dynamic positioning methods will be used during pile driving 
activities.
    Construction of each terminal would require installation and 
removal of temporary steel pipe piles, including template piles, and 
installation of permanent steel pipe piles. Pile installation would 
occur in water depths that range from a few feet or dry (dewatered) 
conditions nearest the shore to approximately 20 meters (70 ft) at the 
outer face of the wharves, depending on tidal stage; the mean diurnal 
tide range at the POA is approximately 8.0 meters (26 ft; NOAA 2015).
    Concurrent Activities--In-water construction activities would occur 
at multiple locations across the project site simultaneously; the POA 
anticipates that two ``spreads'' (a construction crew with crane and 
pile driving hammer) would be on site and working throughout the 
construction season, with a third ``spread'' present on some days. Of 
the two regular spreads, one would be designated for permanent (72-in) 
piles and one for temporary (24-in or 36-in) piles. Each spread would 
operate a single hammer at a time (impact or vibratory), with no more 
than two vibratory hammers simultaneously active in-water at any given 
time. It is not expected that three piles would be driven concurrently, 
and this scenario is not addressed further in this analysis. The only 
combinations of vibratory hammers that could be used simultaneously 
would be for installation of an attenuated (through use of a bubble 
curtain; see Proposed Mitigation later in this notice) 72-in pile and 
an attenuated temporary pile, an attenuated 72-in pile and an 
unattenuated temporary pile, or two temporary piles. There would be no 
simultaneous driving of unattenuated 72-in piles in water. Simultaneous 
use of two hammers would increase production rates.
    Duration of active hammer use is anticipated to be brief each day 
(see table 1), and it is, therefore, anticipated that overlap in use of 
hammers would be uncommon. Pile installation and removal would occur 
intermittently over the work period, for durations of minutes to hours 
at a time. Use of two simultaneous hammers would serve to reduce the 
overall duration of in-water pile installation and removal during each 
construction season. One construction crane would likely be based on a 
floating work barge, and one would likely be based on land or on an 
access trestle. Table 3 provides a summary of concurrent pile driving 
scenarios.

[[Page 85696]]



            Table 3--Potential Concurrent Driving Scenarios That Could Occur During CTR Construction
----------------------------------------------------------------------------------------------------------------
       Equipment type and quantity                    Pile type and size                  Construction months
----------------------------------------------------------------------------------------------------------------
Vibratory x 2...........................  2 x 36-in steel pipe \1\..................  April-July.
Vibratory, Impact.......................  2 x 72-in steel pipe \2\ OR 1 x 72-in       April-November.
                                           steel pipe \2\ (impact) and
                                          1 x 36-in steel pipe (vibratory)..........
----------------------------------------------------------------------------------------------------------------
\1\ POA may elect to use either 36-in or 24-in temporary piles; as 36-in piles are more likely and estimated to
  have larger ensonified areas, we have used these piles in our analyses of concurrent activities;
\2\ All 72-in piles driven concurrently will be attenuated.

    Pile Installation and Removal--Vibratory and impact hammers would 
be used for the installation of 72-in (182-cm) permanent piles. 
Vibratory hammers would be used for installation and removal of 24- 
(61-cm) and or 36-in (91-cm) temporary piles; however, if obstructions 
are encountered during installation, impact driving may be necessary. 
Installation and removal of piles in the dry would be maximized as much 
as feasible, depending on construction sequencing and tide heights. 
However, the exact number of piles that may be installed and removed in 
the dry is unknown (see table 1 for estimates and numbers of piles 
analyzed for in-water construction activities). Impact and vibratory 
pile driving activities conducted in the dry are not expected to impact 
marine mammals and therefore, are not discussed further in this rule.
    Pile Cutting--A majority of in-water temporary piles (approximately 
90 percent) would be cut off at the mudline and remain in place, 
removed via direct pulling, or would remain in place intact (without 
cutting). Temporary piles that conflict with construction or operations 
or that can be removed in the dry would be removed. Leaving piles in 
place below the mudline supports stability of the soil. Also, many of 
the existing T1 and T2 piles are corroded and may break during removal, 
with the lower part remaining in place. The existing structure is 
closer to shore than new construction, and many piles can be cut or 
removed in the dry when their location is dewatered.
    The number of piles that would be cut or remain in place would be 
maximized as feasible; however, the exact number of piles that may be 
cut or can remain in place is unknown (see table 1 for best estimates 
of piles to be removed). While the exact method of pile cutting is at 
the discretion of the construction contractor, any methodology 
considered for cutting and removing the piles would account for worker 
safety, constructability, and minimization of potential acoustic 
impacts that the operation may have on marine mammals. Potential 
methods of underwater cutting include ultrathermic cutting, pile 
clippers or wire-saws.
    Underwater ultrathermic cutting is performed by commercial divers 
using hand-held equipment to cut or melt through ferrous and non-
ferrous metals. These systems operate through a torch-like process, 
initiated by applying a melting amperage to a steel tube packed with 
alloy steel rods, sometimes mixed with aluminum rods to increase the 
heat output. In the hands of skilled commercial divers, underwater 
ultrathermic cutting is reputed to be relatively fast and efficient, 
cutting through approximately 2 to 4 inches (5 to 10 cm) per minute, 
depending upon the number of divers deployed. This efficacy may be 
constrained by the requirement to secure the severed piles from falling 
into the inlet to prevent an extreme hazard to the diver cutting the 
piles. Tidally driven currents in Cook Inlet may limit dive times to 
approximately 2 to 3 hours per high- and low-tide event, depending upon 
the tide cycle and the ability of divers to efficiently perform the 
cutting task while holding position during high current periods. This 
activity is not considered to produce sound.
    Pile clipping and underwater sawing generate noise that is 
typically non-impulsive, low-level, and short duration (typically less 
than 15 seconds per pile) (NAVFAC SW, 2020). Potential pile cutting 
methodologies are not anticipated to result in incidental take of 
marine mammals because they are either above water, do not last for 
sufficient duration to present the reasonable potential for disruption 
of behavioral patterns, do not produce sound levels likely to result in 
marine mammal harassment, or some combination of the above. Impacts on 
marine mammals from pile cutting are therefore considered de minimis 
and NMFS is not proposing to authorize incidental take from this 
activity.
    Demolition of Existing Terminals--Once the new T1, T2, and 
petroleum products transfer system are complete and operational, any 
remaining existing T1, T2, and POL1 platforms, wharves, and trestles 
would be dismantled (see figure 1-5 of the POA's application). Existing 
and most temporary piles would be cut and removed, removed via 
vibratory extraction or direct pull, or left in place. The selection of 
construction equipment by the contractor, including cranes and barges, 
would determine the plans and sequencing for demolition. Portions of 
the existing terminals may be used for construction phasing and as 
support platforms for ongoing new construction, as feasible.
    T3 may be partially demolished during Phase 2B construction of T1 
and T2, especially where the existing infrastructure may interfere with 
new construction. Elements of T3 that remain after Phase 2B is complete 
would remain in place until Phase 5, when they would be removed at that 
time.
    Demolition would take place above the water, and demolished 
decking, pipes, and other superstructure materials would be contained 
before they fall into the water following best management practices. 
Demolished materials would be removed by barge or truck. Because work 
would take place out of water with best management practices in place 
to limit any release of material into Cook Inlet, in addition to 
cutting off or leaving existing piles in place, impacts on marine 
mammals from demolition of the existing terminals are considered de 
minimis and NMFS is not proposing to authorize incidental take from 
this activity.
    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 Specified Geographical Region

    There are seven species, comprising 9 stocks, of marine mammals 
that may be found in upper Cook Inlet during the proposed construction 
and demolition activities. Sections 3 and 4 of the POA's application 
and request for regulations summarize available information regarding 
status and trends, distribution and habitat preferences, and behavior 
and life history of the potentially affected species. NMFS fully 
considered all of this information, and we refer the

[[Page 85697]]

reader to these descriptions, instead of reprinting the information. 
Additional information regarding population trends and threats may be 
found in NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments) and more general information about these species 
(e.g., physical and behavioral descriptions) may be found on NMFS' 
website (https://www.fisheries.noaa.gov/find-species).
    Table 4 lists all species or stocks for which take is likely and 
proposed to be authorized for the specified activities and summarizes 
information related to the population or stock, including regulatory 
status under the MMPA and Endangered Species Act (ESA) and potential 
biological removal (PBR), where known. PBR is defined by the MMPA as 
``the maximum number of animals, not including natural mortalities, 
that may be removed from a marine mammal stock while allowing that 
stock to reach or maintain its optimum sustainable population'' (16 
U.S.C. 1362(20)). While no serious injury or mortality is anticipated 
or proposed to be authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species or stocks and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Alaska and Pacific SARs (e.g., Carretta, et al., 2023; Young 
et al., 2023, 2024). Values presented in table 4 are the most recent 
available at the time of publication (including from the draft 2023 
SARs) and are available online at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports. The most recent abundance estimate for CIBWs is available from 
Goetz et al. (2023) and available online at https://www.fisheries.noaa.gov/feature-story/new-abundance-estimate-endangered-cook-inlet-beluga-whales.

                                              Table 4--Species Likely Impacted by the Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                Stock abundance
                                                                                        ESA/ MMPA status;      Nbest, (CV, Nmin,               Annual M/
            Common name                  Scientific name           MMPA stock         strategic  (Y/N) \1\   most recent abundance     PBR       SI \3\
                                                                                                                  survey) \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Eschrichtiidae:
    Gray whale.....................  Eschrichtius robustus.  Eastern N Pacific.....  -/-; N                  26,960 (0.05, 25,849,        801        131
                                                                                                              2016).
Family Balaenopteridae (rorquals):
    Humpback whale.................  Megaptera novaeangliae  Hawaii................  -, -, N                 11,278 (0.56, 7,265,         127      27.09
                                                                                                              2020).
                                                             Mexico-North Pacific..  T, D, Y                 N/A (N/A, N/A, 2006).    UND \5\       0.57
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                 Order Cetartiodactyla--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer whale...................  Orcinus orca..........  Eastern North Pacific   -/-; N                  1,920 (N/A, 1,920,            19        1.3
                                                              Alaska Resident.                                2019).
                                                             Eastern North Pacific   -/-; N                  587 (N/A, 587, 2012).        5.9        0.8
                                                              Gulf of Alaska,
                                                              Aleutian Islands and
                                                              Bering Sea Transient.
Family Monodontidae:
    Beluga whale...................  Delphinapterus leucas.  Cook Inlet............  E/D; Y                  331 (0.076, 290,            0.53          0
                                                                                                              2022) \4\.
Family Phocoenidae (porpoises):
    Harbor porpoise................  Phocoena phocoena.....  Gulf of Alaska........  -/-; Y                  31,046 (0.214, N/A,      UND \5\         72
                                                                                                              1998).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion...............  Eumetopias jubatus....  Western...............  E/D; Y                  49,837 (N/A, 49,837          299        267
                                                                                                              2022).
Family Phocidae (earless seals):
    Harbor seal....................  Phoca vitulina........  Cook Inlet/Shelikof     -/-; N                  28,411 (N/A, 26,907,         807        107
                                                              Strait.                                         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: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments assessments. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable (N.A.).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range.
\4\ This abundance estimate is from Goetz et al. (2023); which was published after the most recent CIBW SAR (Young et al., 2023).
\5\ UND means undetermined.


[[Page 85698]]

    As indicated above, all seven species (nine managed stocks) in 
table 4 temporally and spatially co-occur with the activity to the 
degree that take is reasonably likely to occur. Minke whales 
(Balaenoptera acutorostrata) and Dall's porpoises (Phocoenoides dalli) 
also occur in Cook Inlet; however, the spatial occurrence of these 
species is such that take is not likely to occur, and they are not 
discussed further beyond the explanation provided here. Data from the 
Alaska Marine Mammal Stranding Network database (NMFS, unpublished 
data) provide additional support for these determinations. From 2011 to 
2020, only one minke whale and one Dall's porpoise were 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. 
With very few exceptions, minke whales and Dall's porpoises do not 
occur in upper Cook Inlet, and therefore, take of these species is 
considered unlikely.
    In addition to what is included in sections 3 and 4 of the POA's 
application (https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization), the SARs (https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessments), and NMFS' 
website, we provide further detail below informing the baseline for 
species likely to be found in the project area (e.g., information 
regarding current UMEs and known important habitat areas, such as 
Biologically Important Areas (BIAs; https://oceannoise.noaa.gov/biologically-important-areas) (Van Parijs et al., 2015)).

Gray Whale

    Gray whales are infrequent visitors to Cook Inlet but can be 
seasonally present during spring and fall in the lower inlet (Bureau of 
Ocean Energy Management (BOEM), 2021). Migrating gray whales pass 
through the lower inlet during their spring and fall migrations to and 
from their primary summer feeding areas in the Bering, Chukchi, and 
Beaufort seas (Swartz, 2018; Silber et al., 2021; BOEM, 2021). There 
are no BIAs for gray whales in Cook Inlet.
    Gray whales are rarely documented in upper Cook Inlet and in the 
project area. Gray whales were not documented during POA construction 
or scientific monitoring from 2005 to 2011 or during 2016 (Prevel-Ramos 
et al., 2006; Markowitz and McGuire, 2007; Cornick and Saxon-Kendall, 
2008, 2009; Cornick et al., 2010, 2011; Integrated Concepts and 
Research Corporation (ICRC), 2009, 2010, 2011, 2012; Cornick and 
Pinney, 2011; Cornick and Seagars, 2016); however, one gray whale was 
observed near Port MacKenzie during 2020 PCT construction (61 North 
(61N) Environmental, 2021) and a second whale was observed off of Ship 
Creek during 2021 PCT construction monitoring (61N Environmental, 
2022a, Easley-Appleyard and Leonard, 2022). The whale observed in 2020 
is believed to be the same whale that later stranded in the Twentymile 
River, at the eastern end of Turnagain Arm, approximately 80 km 
southeast of Knik Arm. There was no indication that work at the PCT had 
any effect on the animal, which was reported to be in ``fair to poor'' 
condition during evaluation (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). No gray 
whales were observed during POA's transitional dredging or SFD 
construction monitoring from May to August, 2022 (61N Environmental, 
2022b, 2022c).
    Under the MMPA, a UME is defined as ``a stranding that is 
unexpected; involves a significant die-off of any marine mammal 
population; and demands immediate response'' (16 U.S.C. 1421h(6)). A 
recently closed UME for gray whales along the West Coast and in Alaska 
occurred from December 17, 2018 through November 9, 2023. During that 
time, 146 gray whales stranded off the coast of Alaska. The 
investigative team concluded that the preliminary cause of the UME was 
localized ecosystem changes in the whale's Subarctic and Arctic feeding 
areas that led to changes in food, malnutrition, decreased birth rates, 
and increased mortality (see https://www.fisheries.noaa.gov/national/marine-life-distress/2019-2023-gray-whale-unusual-mortality-event-along-west-coast-and for more information). Given the changing 
environment in the polar regions due to climate change, there is 
potential for changes to gray whale behavior and distribution in the 
near future.

Humpback Whale

    The 2022 Alaska and Pacific SARs described a revised stock 
structure for humpback whales, which modifies the previous stocks 
designated under the MMPA to align more closely with the ESA-designated 
distinct population segments (DPSs) (Carretta et al., 2023; Young et 
al., 2023). Specifically, the three previous North Pacific humpback 
whale stocks (Central and Western North Pacific stocks and a CA/OR/WA 
stock) were replaced by five stocks, largely corresponding with the 
ESA-designated DPSs. These include Western North Pacific and Hawaii 
stocks and a Central America/Southern Mexico-CA/OR/WA stock (which 
corresponds with the Central America DPS). The remaining two stocks, 
corresponding with the Mexico DPS, are the Mainland Mexico-CA/OR/WA and 
Mexico-North Pacific stocks (Carretta et al., 2023; Young et al., 
2023). The former stock is expected to occur along the west coast from 
California to southern British Columbia, while the latter stock may 
occur across the Pacific, from northern British Columbia through the 
Gulf of Alaska and Aleutian Islands/Bering Sea region to Russia.
    The Hawaii stock consists of one demographically independent 
population (DIP) (Hawaii--Southeast Alaska/Northern British Columbia 
DIP) and the Hawaii--North Pacific unit, which may or may not be 
composed of multiple DIPs (Wade et al., 2021). The DIP and unit are 
managed as a single stock at this time, due to the lack of data 
available to separately assess them and lack of compelling conservation 
benefit to managing them separately (NMFS, 2019, 2022b, 2023). The DIP 
is delineated based on two strong lines of evidence: genetics and 
movement data (Wade et al., 2021). Whales in the Hawaii--Southeast 
Alaska/Northern British Columbia DIP winter off Hawaii and largely 
summer in Southeast Alaska and Northern British Columbia (Wade et al., 
2021). The group of whales that migrate from Russia, western Alaska 
(Bering Sea and Aleutian Islands), and central Alaska (Gulf of Alaska 
excluding Southeast Alaska) to Hawaii have been delineated as the 
Hawaii-North Pacific unit (Wade et al., 2021). There are a small number 
of whales that migrate between Hawaii and southern British Columbia/
Washington, but current data and analyses do not provide a clear 
understanding of which unit these whales belong to (Wade et al., 2021; 
Carretta et al., 2023; Young et al., 2023).
    The Mexico-North Pacific stock is likely composed of multiple DIPs, 
based on movement data (Martien et al., 2021; Wade, 2021; Wade et al., 
2021). However, because currently available data and analyses are not 
sufficient to delineate or assess DIPs within the unit, it was 
designated as a single stock (NMFS, 2019, 2022c, 2023). Whales in this 
stock winter off Mexico and the Revillagigedo Archipelago and summer 
primarily in Alaska waters (Martien et al., 2021; Carretta et al., 
2023; Young et al., 2023).

[[Page 85699]]

    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 stock, 11 percent are from the Mexico-
North Pacific stock, and less than 1 percent are from the Western North 
Pacific stock (Wade, 2021). Members of different stocks are known to 
intermix in feeding grounds.
    On October 9, 2019, NMFS proposed to designate critical habitat for 
the Western North Pacific, Mexico, and Central America DPSs of humpback 
whales (84 FR 54354). NMFS issued a final rule on April 21, 2021 to 
designate critical habitat for ESA-listed humpback whales pursuant to 
section 4 of the ESA (86 FR 21082). There is no designated critical 
habitat for humpback whales in or near the Project area (86 FR 21082, 
April 21, 2021), nor does the project overlap with any known BIAs.
    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). During aerial surveys 
conducted in summers between 2005 and 2012, Shelden et al. (2013) 
reported dozens of sightings in lower Cook Inlet, a handful of 
sightings in the vicinity of Anchor Point and in lower Cook Inlet, and 
no sightings north of 60[deg] N latitude. 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). No survey took place in 
2020. Instead, consecutive surveys took place in 2021 and 2022 (Shelden 
et al., 2022). During the 2014-2022 aerial surveys, sightings of 
humpback whales were recorded in lower Cook Inlet and mid-Cook Inlet, 
but none were observed in upper Cook Inlet (Shelden et al., 2015b, 
2017, 2019, 2022). Vessel-based observers participating in the Apache 
Corporation's 2014 survey operations recorded three humpback whale 
sightings near Moose Point in upper Cook Inlet and two sightings near 
Anchor Point, while aerial and land-based observers recorded no 
humpback whale sightings, including in the upper inlet (Lomac-MacNair 
et al., 2014). Observers monitoring waters between Point Campbell and 
Fire Island during summer and fall 2011 and spring and summer 2012 
recorded no humpback whale sightings (Brueggeman et al., 2013). 
Monitoring of Turnagain Arm during ice-free months between 2006 and 
2014 yielded one humpback whale sighting (McGuire, unpublished data, 
cited in LGL Alaska Research Associates, Inc., and DOWL, 2015).
    There have been few sightings of humpback whales in the vicinity of 
the proposed project area. Humpback whales were not documented during 
POA construction or scientific monitoring from 2005 to 2011, in 2016, 
or during 2020 (Prevel-Ramos et al., 2006; Markowitz and McGuire, 2007; 
Cornick and Saxon-Kendall, 2008, 2009; Cornick et al., 2010, 2011; 
ICRC, 2009, 2010, 2011, 2012; Cornick and Pinney, 2011; Cornick and 
Seagars, 2016; 61N Environmental, 2021). 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 (POA, 2017). 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. Another juvenile humpback 
stranded in Turnagain Arm in April 2019 near mile 86 of the Seward 
Highway. One additional humpback whale was observed in July during 2022 
transitional dredging monitoring (61N Environmental, 2022c). No 
humpback whales were observed during the 2020 to 2021 PCT construction 
monitoring, the NMFS marine mammal monitoring, or the 2022 SFD 
construction monitoring from April to June (61N Environmental, 2021, 
2022a, 2022b, 2022c; Easley-Appleyard and Leonard, 2022).

Killer Whale

    Killer whales are rare in Cook Inlet, and there are no known BIAs 
for this species in Cook Inlet. Most sightings of killer whales in the 
area are in lower Cook Inlet (Shelden et al., 2013). 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 beluga whales for transient killer whales) are also in the 
area (Shelden et al., 2003). During CIBW aerial surveys between 1993 
and 2012, killer whales were sighted in lower Cook Inlet 17 times, with 
a total of 70 animals (Shelden et al., 2013); no killer whales were 
observed in upper Cook Inlet during this time. Surveys over 20 years by 
Shelden et al. (2003) documented an increase in CIBW sightings and 
strandings in upper Cook Inlet beginning in the early 1990s. Several of 
these sightings and strandings reported evidence of killer whale 
predation on CIBWs. The pod sizes of killer whales preying on CIBWs 
ranged from one to six individuals (Shelden et al., 2003). Passive 
acoustic monitoring efforts throughout Cook Inlet documented killer 
whales at the Beluga River, Kenai River, and Homer Spit, although they 
were not encountered within Knik Arm (Castellote et al., 2016). These 
detections were likely resident killer whales. Transient killer whales 
likely have not been acoustically detected due to their propensity to 
move quietly through waters to track prey (Small, 2010; Lammers et al., 
2013).
    Few killer whales, if any, are expected to approach or be in the 
vicinity of the proposed project area. No killer whales were spotted in 
the vicinity of the POA during surveys by Funk et al. (2005), Ireland 
et al. (2005), or Brueggeman et al. (2007, 2008a, 2008b). Killer whales 
have also not been documented during any POA construction or scientific 
monitoring from 2005 to 2011, in 2016, or in 2020 (Prevel-Ramos et al., 
2006; Markowitz and McGuire, 2007; Cornick and Saxon-Kendall, 2008; 
ICRC, 2009, 2010, 2011, 2012; Cornick et al., 2010, 2011; Cornick and 
Pinney, 2011; Cornick and Seagars, 2016; 61N Environmental, 2021). Two 
killer whales, one male and one juvenile of unknown sex, were sighted 
offshore of Point Woronzof in September 2021 during PCT Phase 2 
construction monitoring (61N Environmental, 2022a). The pair of killer 
whales moved up Knik Arm, reversed direction near Cairn Point, and 
moved southwest out of Knik Arm toward the open water of Upper Cook 
Inlet. No killer whales were sighted during the 2021 NMFS marine mammal 
monitoring or the 2022 transitional dredging and SFD construction 
monitoring that occurred between May and June 2022 (61N Environmental, 
2022b, 2022c; Easley-Appleyard and Leonard, 2022).

Beluga Whale

    Five stocks of beluga whales are recognized in Alaska: the Beaufort 
Sea stock, eastern Chukchi Sea stock, eastern Bering Sea stock, Bristol 
Bay stock, and Cook Inlet stock (Young et al., 2023). The Cook Inlet 
stock is geographically and genetically isolated from the other stocks 
(O'Corry-Crowe et al., 1997; Laidre et al., 2000) and resides year-
round in Cook Inlet (Laidre et al., 2000; Castellote et al., 2020). 
Only the CIBW stock inhabits the proposed project area. CIBWs were 
designated as a DPS and listed as endangered under the ESA in October 
2008 (73 FR 62919, October 10, 2008).

[[Page 85700]]

    On June 15, 2023, NMFS released an updated abundance estimate for 
CIBWs (Goetz et al., 2023) that incorporates aerial survey data from 
June 2021 and 2022, which represents an update from the most recent SAR 
(Young et al., 2023) and suggest that the CIBW population is stable or 
may be slightly increasing. The methodology in the 2023 report is the 
same as that used for NMFS's SARs (Young et al. 2023) and incorporates 
the same time-series of data from previous years. The only change was 
the inclusion of more recent data from 2021 and 2022 surveys; the 2021 
data collection efforts were delayed from 2020 due to COVID-19. Goetz 
et al. (2023) estimated that the population size is currently between 
290 and 386, with a median best estimate of 331. We have determined 
that Goetz et al. (2023) represents the most recent and best available 
science.
    Goetz et al. (2023) also present an analysis of population trends 
for the most recent 10-year period (2012-2022). The addition of data 
from the 2021 and 2022 survey years in the analysis resulted in a 65.1 
percent probability that the CIBW population is now increasing at 0.9 
percent per year (95 percent prediction interval of -3 to 5.7 percent). 
This increase drops slightly to 0.2 percent per year (95 percent 
prediction interval of -1.8 to 2.6 percent) with a 60 percent 
probability that the CIBW population is increasing more than 1 percent 
per year when data from 2021, which had limited survey coverage due to 
poor weather, are excluded from the analysis. Median group size 
estimates in 2021 and 2022 were 34 and 15, respectively (Goetz et al., 
2023). NMFS has determined that the carrying capacity of Cook Inlet is 
1,300 CIBWs (65 FR 34590, May 31, 2000) based on historical CIBW 
abundance estimated by Calkins (1989). Additional information may be 
found in NMFS' 2023 report on the abundance and trend of CIBWs in Cook 
Inlet in June 2021 and June 2022, available online at https://www.fisheries.noaa.gov/resource/document/abundance-and-trend-belugas-delphinapterus-leucas-cook-inlet-alaska-june-2021-and.
    Live stranding events of CIBWs have been regularly observed in 
upper Cook Inlet. This can occur when an individual or group of 
individuals strands as the tide recedes. Most live strandings have 
occurred in Knik Arm and Turnagain Arm, which are shallow and have 
large tidal ranges, strong currents, and extensive mudflats. 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 3 known live stranding events plus 1 
suspected live stranding event with two associated deaths reported 
(NMFS, 2016b; NMFS, unpublished data; Muto et al., 2020). 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.
    Another source of CIBW mortality in Cook Inlet is predation by 
transient-type (mammal-eating) killer whales (NMFS, 2016b; Shelden et 
al., 2003). No human-caused mortality or serious injury of CIBWs 
through interactions with commercial, recreational, and subsistence 
fisheries or because of other human-caused events (e.g., entanglement 
in marine debris, ship strikes) has been recently documented, and 
subsistence harvesting of CIBWs has not occurred since 2008 (NMFS, 
2008b).
    Recovery Plan. The Final Recovery Plan for CIBW was published in 
the Federal Register on January 5, 2017 (82 FR 1325), available online 
at https://www.fisheries.noaa.gov/resource/document/recovery-plan-cook-inlet-beluga-whale-delphinapterus-leucas.
    In its Recovery Plan (82 FR 1325, January 5, 2017), NMFS identified 
several potential threats to CIBWs, including: (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 prohibited 
take (e.g., entanglements, strikes, poaching or intentional harassment, 
and close approaches by private vessels); 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 vessel strikes.
    Critical Habitat. On April 11, 2011, NMFS designated two areas of 
critical habitat for CIBW (76 FR 20179). The designation includes 7,800 
km\2\ of marine and estuarine habitat within Cook Inlet, encompassing 
approximately 1,909 km\2\ in Area 1 and 5,891 km\2\ in Area 2 (see 
figure 1 in 76 FR 20179). Area 1 of the CIBW critical habitat 
encompasses all marine waters of Cook Inlet north of a line connecting 
Point Possession (lat. 61.04[deg] N, long. 150.37[deg] W) and the mouth 
of Three Mile Creek (lat. 61.08.55[deg] N, long. 151.04.40[deg] W), 
including waters of the Susitna, Little Susitna, and Chickaloon Rivers 
below mean higher high water. From spring through fall, Area 1 critical 
habitat has the highest concentration of CIBWs due to its important 
foraging and calving habitat. Area 2 critical habitat has a lower 
concentration of CIBWs in spring and summer but is used by CIBWs in 
fall and winter. Critical habitat does not include two areas of 
military usage: the Eagle River Flats Range on Fort Richardson and 
military lands of JBER between Mean Higher High Water and MHW. 
Additionally, the POA, adjacent navigation channel, and turning basin 
(approximately 6.84 km\2\) were excluded from the critical habitat 
designation due to national security reasons (76 FR 20180, April 11, 
2011). The POA exclusion area is within Area 1, however, marine mammal 
monitoring results from the POA suggest that this exclusion area is not 
a particularly important feeding or calving area. CIBWs have been 
occasionally documented to forage around Ship Creek (south of the POA) 
but are typically transiting through the area to other, potentially 
richer, foraging areas to the north (e.g., Six Mile Creek, Eagle River, 
Eklutna River) (e.g., 61N Environmental, 2021, 2022a, 2022b, 2022c, 
Easley-Appleyard and Leonard, 2022). These locations contain 
predictable salmon runs, 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). More information on CIBW 
critical habitat can be found at https://www.fisheries.noaa.gov/action/critical-habitat-cook-inlet-beluga-whale.
    The designation identified the following Primary Constituent 
Elements (PCE), essential features important to the conservation of the 
CIBW:
    (1) Intertidal and subtidal waters of Cook Inlet with depths of 
less than 9 m (MLLW) and within 8 km of high- and medium-flow 
anadromous fish streams;
    (2) Primary prey species, including four of the five species of 
Pacific salmon (chum (Oncorhynchus keta), sockeye (Oncorhynchus nerka), 
Chinook (Oncorhynchus tshawytscha), and coho (Oncorhynchus kisutch)), 
Pacific eulachon (Thaleichthys pacificus), Pacific cod (Gadus 
macrocephalus), walleye pollock (Gadus chalcogrammus), saffron cod 
(Eleginus

[[Page 85701]]

gracilis), and yellowfin sole (Limanda aspera);
    (3) The absence of toxins or other agents of a type or amount 
harmful to CIBWs;
    (4) Unrestricted passage within or between the critical habitat 
areas; and
    (5) The absence of in-water noise at levels resulting in the 
abandonment of habitat by CIBWs.
    The area around the POA, while exempted from the Critical Habitat 
designation due to national security issues, does contain the requisite 
bathymetric features in the first PCE, as well as the presence of 
primary prey species. However, given the industrialized nature of the 
POA and the historical use of the site from the early 1900s, the other 
physical features are more difficult to confirm. Sediment contamination 
was examined during a 2008 U.S. Army Corps of Engineers dredging 
project near the Port, and contaminant levels of volatile and semi-
volatile organic compounds, total recoverable petroleum hydrocarbons, 
PCBs, pesticides, cadmium, mercury, selenium, silver, arsenic, barium, 
chromium, and lead were found to be suitable for in-water discharge 
(USACE 2008). Ambient and background noise levels at the POA have been 
measured and are addressed quantitatively later in this document; 
briefly, noise levels are elevated due to both anthropogenic activities 
(i.e., commercial shipping, dredging, and construction) and normal 
environmental factors (e.g., high current velocity, ice movement, 
seismic activity). While neither contaminants nor noise have been shown 
to approach the ``harmful'' and ``habitat abandonment'' thresholds 
described in the PCEs, the concentration of both stressors is highest 
closer to the POA facilities, within the exemption area, ultimately 
degrading the habitat at POA relative to the surrounding areas. In 
total, the exempted area surrounding the POA represents approximately 
0.35 percent of the designated Critical Habitat Area 1.
    Biologically Important Areas. Wild et al. (2023) delineated 
portions of Cook Inlet, including near the proposed project area, as a 
BIA for the small and resident population of CIBWs based on scoring 
methods outlined by Harrison et al. (2023) (see https://oceannoise.noaa.gov/biologically-important-areas for more information). 
The BIA is used year-round by CIBWs for feeding and breeding, and there 
are limits on food supply such as salmon runs and seasonal movement of 
other fish species (Wild et al., 2023). The boundary of the CIBW BIA is 
consistent with NMFS' critical habitat designation and does not include 
the aforementioned exclusion areas (e.g., the POA and surrounding 
waters) (Wild et al., 2023).
    Foraging Ecology. CIBWs feed on a wide variety of prey species, 
particularly those that are seasonally abundant. From late spring 
through summer, most CIBW stomachs sampled contained salmon, which 
corresponded to the timing of fish runs in the area. Anadromous smolt 
and adult fish aggregate at river mouths and adjacent intertidal 
mudflats (Calkins, 1989). All five Pacific salmon species (i.e., 
Chinook, pink (Oncorhynchus gorbuscha), coho, sockeye, and chum) spawn 
in rivers throughout Cook Inlet (Moulton, 1997; Moore et al., 2000). 
Overall, Pacific salmon represent the highest percent frequency of 
occurrence of prey species in CIBW stomachs. This suggests that their 
spring feeding in upper Cook Inlet, principally on fat-rich fish, such 
as salmon and eulachon, is important to the energetics of these animals 
(NMFS, 2016b).
    The nutritional quality of Chinook salmon in particular is 
unparalleled, with an energy content four times greater than that of a 
Coho salmon. It is suggested the decline of the Chinook salmon 
population has left a nutritional void in the diet of the CIBWs that no 
other prey species can fill in terms of quality or quantity (Norman et 
al., 2020, 2022).
    In fall, as anadromous fish runs begin to decline, CIBWs consume 
fish species (cod and bottom fish) found in nearshore bays and 
estuaries. Stomach samples from CIBWs are not available for winter 
(December through March), although dive data from CIBWs tagged with 
satellite transmitters suggest that they feed in deeper waters during 
winter (Hobbs et al., 2005), possibly on such prey species as flatfish, 
cod, sculpin, and pollock.
    Fish runs in the Anchorage and Matanuska-Susitna area include 
Chinook (May-August), sockeye (June-September), coho (July-September), 
pin (July-August), and chum (July-September) salmon, as well as dolly 
varden, rainbow and lake trout, northern pike, burbot, grayling, smelt, 
and whitefish. In proximity to the POA, anadromous fish runs occur at 
Ship Creek, which is heavily used by recreational anglers. On June 26, 
2024, the Alaska Department of Fish and Game (ADF&G) issued an 
emergency closure of recreational fishing on Ship Creek until July 13, 
2024, and limited Chinook catching to catch-and-release for the 
remainder of the season due to low returns of Chinook in the creek. 
ADF&G anticipates a poor return of this species throughout Knik Arm for 
2024, in keeping with a trend of declining Chinook Runs throughout Cook 
Inlet since 2008 (ADF&G 2019). The Gulf of Alaska Chinook salmon is 
currently under review for listing under the ESA (89 FR 45815, May 24, 
2024).
    Distribution in Cook Inlet. 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). During 
spring and summer, CIBWs generally aggregate near the warmer waters of 
river mouths where prey availability is high and predator occurrence is 
low (Moore et al., 2000; Shelden and Wade, 2019; McGuire et al., 2020). 
In particular, CIBW groups are seen in the Susitna River Delta 
approximately 36 km (23 mi) to the west of the POA across the mouth of 
Knik arm in Upper Cook Inlet, the Beluga River (approximately 55 km (34 
mi) west) and along the shore to the Little Susitna River (21 km (13 
mi) west), within all of Knik Arm, and along the shores of Chickaloon 
Bay to the south of Anchorage, across Turnagain Arm (figure 3). Small 
groups were recorded farther south in Kachemak Bay, Redoubt Bay (Big 
River), and Trading Bay (McArthur River) prior to 1996 but rarely 
thereafter. Since the mid-1990s, most CIBWs (96 to 100 percent) 
aggregate in shallow areas near river mouths in upper Cook Inlet, and 
they are only occasionally sighted in the central or southern portions 
of Cook Inlet during summer (Hobbs et al., 2008). Almost the entire 
population can be found in northern Cook Inlet from late spring through 
the summer and into the fall (Muto et al., 2020).

[[Page 85702]]

[GRAPHIC] [TIFF OMITTED] TP28OC24.004

    Data from tagged whales (14 tags deployed July 2000 through March 
2003) show that CIBWs use upper Cook Inlet intensively between summer 
and late autumn (Hobbs et al., 2005). CIBWs tagged with satellite 
transmitters continue to use Knik Arm, Turnagain Arm, and Chickaloon 
Bay as late as October, but some range into lower Cook Inlet to 
Chinitna Bay, Tuxedni Bay, and Trading Bay (McArthur River) in fall 
(Hobbs et al., 2005, 2012). From September through November, CIBWs move 
between Knik Arm, Turnagain Arm, and Chickaloon Bay (Hobbs et al., 
2005; Goetz et al., 2012b). By December, CIBWs are distributed 
throughout the upper to mid-inlet. From January into March, they move 
as far south as Kalgin Island and slightly beyond in central offshore 
waters. CIBWs make occasional excursions into Knik Arm and Turnagain 
Arm in February and March in spite of ice cover (Hobbs et al., 2005). 
Although tagged CIBWs move widely around Cook Inlet throughout the 
year, there is no indication of seasonal migration in and out of Cook 
Inlet (Hobbs et al., 2005). Data from NMFS aerial surveys, 
opportunistic sighting reports, and corrected satellite-tagged CIBWs 
confirm that they are more widely dispersed throughout Cook Inlet 
during winter (November-April), with animals found between Kalgin 
Island and Point Possession. Generally fewer observations of CIBWs are 
reported from the Anchorage and Knik Arm area from November through 
April as documented

[[Page 85703]]

in the designation of Critical Habitat (76 FR 20179, April 11, 2011; 
Rugh et al., 2000, 2004).
    The NMFS 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 6 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, particularly in Tuxedni Bay in the months of September 
through March (Castellote et al., 2015, 2018, 2024; Castellote et al. 
2024).
    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 groups. CIBW presence and 
acoustic foraging behavior also increased closer to rivers with Chinook 
salmon runs, such as the Susitna River (e.g., Castellote et al., 2021). 
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[hyphen]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 are believed to mostly calve in the summer and concurrently 
breed between late spring and early summer (NMFS, 2016b), primarily in 
upper Cook Inlet. McGuire et al. (2020) documented three suspected 
calving events between July and September with no neonates observed 
during surveys conducted from April to June. The first neonates 
encountered during each field season from 2005 through 2015 were always 
seen in the Susitna River Delta in July. Important calving grounds are 
thought to be located near the river mouths of upper Cook Inlet--both 
potential births documented in July were at the Susitna River Delta; 
the third was in Turnagain Arm in September (McGuire et al., 2020). 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 during all months of the aerial surveys (McGuire et al., 
2020). Young CIBWs are nursed for 2 years and may continue to associate 
with their mothers for a considerable time thereafter (Colbeck et al., 
2013). Demographic rates were modeled for this population, indicating 
that low survival of non-breeding (i.e., subadult, male, and non-
breeding adult female) CIBWs and general low reproductive rates are 
likely contributing to the non-recovery of the population (Himes Boor 
et al., 2022).
    Presence in Project Area. Knik Arm is one of three areas in upper 
Cook Inlet where CIBWs are concentrated during spring, summer, and 
early fall. Most CIBWs observed in or near the POA are transiting 
between upper Knik Arm and other portions of Cook Inlet, and the POA 
itself is not considered high-quality foraging habitat. CIBWs tend to 
follow their anadromous prey and travel in and out of Knik Arm with the 
tides. The predictive habitat model derived by Goetz et al. (2012a) 
indicated that the highest predicted densities of CIBWs are in Knik Arm 
near the mouth of the Susitna River and in Chickaloon Bay. The model 
suggests that the density of CIBWs ranges from 0 to 1.12 whales per 
km\2\ in Cook Inlet but is lower at the mouth of Knik Arm, near the 
POA, ranging between approximately 0.013 and 0.062 whales per km\2\. 
The distribution presented by Goetz et al. (2012a) is generally 
consistent with CIBW distribution documented in upper Cook Inlet 
throughout ice-free months (NMFS, 2016b).
    Several marine mammal monitoring programs and studies have been 
conducted at or near the POA during the last 17 years. These studies 
offer some of the best available information on the presence of CIBWs 
in the proposed project area. Studies that occurred prior to 2020 are 
summarized in Section 4.5.5 of the POA's application. More recent 
programs, which most accurately portray current information regarding 
CIBW presence in the proposed project area, are summarized here.
    PCT Construction Monitoring (2020-2021). A marine mammal monitoring 
program was implemented during construction of the PCT in 2020 (Phase 
1) and 2021 (Phase 2), as required by the NMFS IHAs (85 FR 19294, April 
6, 2020). PCT Phase 1 construction included impact installation of 48-
in (122-cm) attenuated piles; impact installation of 36-in (91-cm) and 
48-in (122-cm) unattenuated piles; vibratory installation of 24-in (61-
cm), 36-in (91-cm), and 48-in (122 cm) attenuated and unattenuated 
piles; and vibratory installation of an unattenuated 72-in (183-cm) 
casing for a confined bubble curtain across 95 days. PCT Phase 2 
construction included vibratory installation of 36-in (91-cm) 
attenuated piles and impact and vibratory installation of 144-in (366-
cm) attenuated breasting and mooring dolphins across 38 days. Marine 
mammal monitoring in 2020 occurred during 128 non-consecutive days with 
a total of 1,238.7 hours of monitoring from April 27 to November 24, 
2020 (61N Environmental, 2021). Marine mammal monitoring in 2021 
occurred during 74 non-consecutive days with a total of 734.9 hours of 
monitoring from April 26 to June 24 and September 7 to 29, 2021 (61N 
Environmental, 2022a). A total of 1,504 individual CIBWs across 377 
groups were sighted during PCT construction monitoring. Sixty-five and 
67 percent of CIBW observations occurred on non-pile driving days or 
before pile driving occurred on a given day during PCT Phase 1 and PCT 
Phase 2 construction, respectively.
    The monitoring effort and data collection were conducted before, 
during, and after pile driving activities from four locations as 
stipulated by the PCT IHAs (85 FR 19294, April 6, 2020): (1) the 
Anchorage Public Boat Dock by Ship Creek, (2) the Anchorage Downtown 
Viewpoint near Point Woronzof, (3) the PCT construction site, and (4) 
the North End (North Extension) at the north end of the POA, near Cairn 
Point. Marine mammal sighting data from April to September both before, 
during, and after pile driving indicate that CIBWs swam near the POA 
and lingered there for periods of time ranging from a few minutes to a 
few hours. CIBWs were most often seen traveling at a slow or moderate 
pace, either from the north near Cairn Point or from the south or 
milling at the

[[Page 85704]]

mouth of Ship Creek. Groups of CIBWs were also observed swimming north 
and south in front of the PCT construction and did not appear to 
exhibit avoidance behaviors either before, during, or after pile 
driving activities (61N Environmental, 2021, 2022a). CIBW sightings in 
June were concentrated on the west side of Knik Arm from the Little 
Susitna River Delta to Port MacKenzie. From July through September, 
CIBWs were most often seen milling and traveling on the east side of 
Knik Arm from Point Woronzof to Cairn Point (61N Environmental, 2021, 
2022a).
    SFD Construction Monitoring and Transitional Dredging (2022). In 
2022, a marine mammal monitoring program almost identical to that used 
during PCT construction was implemented during construction of the SFD, 
as required by the NMFS IHA (86 FR 50057, September 7, 2021). SFD 
construction included the vibratory installation of ten 36-in (91-cm) 
attenuated plumb piles and two unattenuated battered piles (61N 
Environmental, 2022b). Marine mammal monitoring was conducted during 13 
non-consecutive days with a total of 108.2 hours of monitoring 
observation from May 20 through June 11, 2022 (61N Environmental, 
2022b). Forty-one individual CIBWs across 9 groups were sighted (61N 
Environmental, 2022b). One group was observed on a day with no pile-
driving, three groups were seen on days before pile driving activities 
started, and five groups were seen during vibratory pile driving 
activities (61N Environmental, 2022b).
    During SFD construction, the position of the Ship Creek monitoring 
station was adjusted to allow monitoring of a portion of the shoreline 
north of Cairn Point that could not be seen by the station at the 
northern end of the POA (61N Environmental, 2022b). Eleven protected 
species observers (PSOs) worked from four monitoring stations located 
along a 9-km (6-mi) stretch of coastline surrounding the POA. The 
monitoring effort and data collection were conducted at the following 
four locations: (1) Point Woronzof approximately 6.5 km (4 mi) 
southwest of the SFD, (2) the promontory near the boat launch at Ship 
Creek, (3) the SFD project site, and (4) the northern end of the POA 
(61N Environmental, 2022b).
    Ninety groups comprised of 529 CIBWs were also sighted during the 
transitional dredging monitoring that occurred from May 3 to 15, 2022 
and June 27 to August 24, 2022 (61N Environmental, 2022b). Of the nine 
groups of CIBWs sighted during SFD construction, traveling was recorded 
as the primary behavior for each group (61N Environmental, 2022b). 
CIBWs traveled and milled between the SFD construction area, Ship 
Creek, and areas to the south of the POA for more than an hour at a 
time, delaying some construction activities.

Harbor Porpoise

    Harbor porpoises occur throughout Cook Inlet with passive acoustic 
detections being more prevalent in lower Cook Inlet. 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 are no known BIAs for 
harbor porpoise in Cook Inlet.
    An increase in harbor porpoise sightings in upper Cook Inlet has 
been observed over recent decades (e.g., 61N Environmental, 2021, 
2022a; 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). The overall increase in the number 
of harbor porpoise sightings in upper Cook Inlet is unknown, although 
it may be an artifact from increased studies and marine mammal 
monitoring programs in upper Cook Inlet. It is also possible that the 
apparent contraction in the CIBW's range has opened up previously 
occupied CIBW range to harbor porpoises (Shelden et al., 2014).
    Harbor porpoises have been observed within Knik Arm during 
monitoring efforts from 2005 to 2016. Between April 27 and November 24, 
2020, 18 harbor porpoises were observed near the POA during the PCT 
Phase 1 construction monitoring (61N Environmental, 2021). Twenty-seven 
harbor porpoises were observed near the POA during the PCT Phase 2 
construction monitoring conducted between April 26 and September 29, 
2021 (61N Environmental, 2022a). During NMFS marine mammal monitoring 
conducted in 2021, one harbor porpoise was observed in August and six 
harbor porpoises were observed in October (Easley-Appleyard and 
Leonard, 2022). During 2022, five harbor porpoises were sighted during 
transitional dredging monitoring (61N Environmental, 2022c). No harbor 
porpoises were sighted at the POA during the 2022 SFD construction 
monitoring that occurred between May and June 2022 (61N Environmental, 
2022b).

Steller Sea Lion

    Two DPSs of Steller sea lion occur in Alaska: the western DPS and 
the eastern DPS. The western DPS includes animals that occur west of 
Cape Suckling, Alaska and therefore, includes individuals within the 
Project area. The western DPS was listed under the ESA as threatened in 
1990 (55 FR 49204, November 26, 1990), and its continued population 
decline resulted in a change in listing status to endangered in 1997 
(62 FR 24345, May 5, 1997). Since 2000, studies indicate that the 
population east of Samalga Pass (i.e., east of the Aleutian Islands) 
has increased and is potentially stable (Young et al., 2023).
    NMFS designated critical habitat for Steller sea lions on August 
27, 1993 (58 FR 45269). The critical habitat designation for the 
Western DPS of was determined to include a 37-km (20-nautical mile) 
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. There are no 
known BIAs for Steller sea lions in Cook Inlet.
    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 not been documented in upper Cook Inlet during CIBW aerial 
surveys conducted annually in June from 1994 through 2012 and in 2014 
(Shelden et al., 2013, 2015b, 2017; Shelden and Wade, 2019); however, 
there has been an increase in individual Steller sea lion sightings 
near the POA in recent years.
    Steller sea lions were observed near the POA in 2009, 2016, and 
2019 through 2022 (ICRC, 2009; Cornick and Seagars, 2016; POA, 2019; 
61N Environmental, 2021, 2022a, 2022b, 2022c). In 2009, there were 
three Steller sea lion sightings that were believed to be the same 
individual (ICRC, 2009). In 2016, Steller sea lions were observed on 2 
separate days. On May 2, 2016, one individual was sighted, while 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 (Cornick and Seagars, 2016). Given the proximity in time and 
space, it is believed these five sightings were of the same individual 
sea lion. In 2019, one Steller sea lion was observed in June at the POA 
during transitional dredging (POA,

[[Page 85705]]

2019). There were six sightings of individual Steller sea lions near 
the POA during PCT Phase 1 construction monitoring (61N 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 (61N 
Environmental, 2021). In 2021, there were a total of eight sightings of 
individual Steller sea lions observed near the POA during PCT Phase 2 
construction monitoring (61N Environmental, 2022a). During NMFS marine 
mammal monitoring, one Steller sea lion was observed in August 2021 in 
the middle of the inlet (Easley-Appleyard and Leonard, 2022). In 2022, 
there were three Steller sea lion sightings during the transitional 
dredging monitoring and three during SFD construction monitoring (61N 
Environmental, 2022b, 2022c). All sightings occurred during summer, 
when the sea lions were likely attracted to ongoing salmon runs. Sea 
lion observations near the POA may be increasing due to more consistent 
observation effort or due to increased presence; observations continue 
to be occasional.

Harbor Seal

    Harbor seals 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), though there are 
no known BIAs for this species in this area. Recent research on 
satellite-tagged harbor seals 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 Shumagin Islands. During summer months, movements and 
distribution were 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). In the fall, a portion 
of the harbor seals appeared to move out of Cook Inlet and into 
Shelikof Strait, northern Kodiak Island, and coastal habitats of the 
Alaska Peninsula. The western coast of Cook Inlet had higher usage by 
harbor seals than eastern coast habitats, and seals captured in lower 
Cook Inlet generally exhibited site fidelity by remaining south of the 
Forelands in lower Cook Inlet after release (south of Nikiski; 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 
in lower Cook Inlet; however, there are a few haulout sites in upper 
Cook Inlet, including near the Little and Big Susitna rivers, Beluga 
River, Theodore River, and Ivan River (Barbara Mahoney, personal 
communication, November 16, 2020; Montgomery et al., 2007). During CIBW 
aerial surveys of upper Cook Inlet from 1993 to 2012, harbor seals were 
observed 24 to 96 km south-southwest of Anchorage at the Chickaloon, 
Little Susitna, Susitna, Ivan, McArthur, and Beluga rivers (Shelden et 
al., 2013). Harbor seals have been observed in Knik Arm and in the 
vicinity of the POA (Shelden et al., 2013), but they are not known to 
haul out within the proposed project area.
    Harbor seals were observed during construction monitoring at the 
POA from 2005 through 2011 and in 2016, in groups of one to seven 
individuals (Prevel-Ramos et al., 2006; Markowitz and McGuire, 2007; 
Cornick and Saxon-Kendall, 2008, 2009; Cornick et al., 2010, 2011; 
Cornick and Seagars, 2016). Harbor seals were also observed near the 
POA during construction monitoring for PCT Phase 1 in 2020 and PCT 
Phase 2 in 2021, NMFS marine mammal monitoring in 2021, and 
transitional dredging monitoring and SFD construction monitoring in 
2022 (61N Environmental, 2021, 2022a, 2022b, 2022c, Easley-Appleyard 
and Leonard, 2022). During the 2020 PCT Phase 1 and 2021 PCT Phase 2 
construction monitoring, harbor seals were regularly observed in the 
vicinity of the POA with frequent observations near the mouth of Ship 
Creek, located approximately 1,500 m southeast of the CTR location. 
Harbor seals were observed almost daily during 2020 PCT Phase 1 
construction, with 54 individuals documented in July, 66 documented in 
August, and 44 sighted in September (61N Environmental, 2021). During 
the 2021 PCT Phase 2 construction, harbor seals were observed with the 
highest numbers of sightings in June (87 individuals) and in September 
(124 individuals) (61 N Environmental, 2022a). Over the 13 days of SFD 
construction monitoring in May and June 2022, 27 harbor seals were 
observed (61N Environmental, 2022b). Seventy-two groups of 75 total 
harbor seals (3 groups of 2 individuals) were observed during 
transitional dredging monitoring in 2022 (61N Environmental, 2022c). 
Sighting rates of harbor seals have been highly variable and may have 
increased since 2005. It is unknown whether any potential increase was 
due to local population increases or habituation to ongoing 
construction activities. It is possible that increased sighting rates 
are correlated with more intensive monitoring efforts in 2020 and 2021, 
when the POA used 11 PSOs spread among four monitoring stations.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Not all marine mammal species have equal 
hearing capabilities (e.g., Richardson et al., 1995; Wartzok and 
Ketten, 1999; Au and Hastings, 2008). To reflect this, Southall et al. 
(2007, 2019) recommended that marine mammals be divided into hearing 
groups based on directly measured (behavioral or auditory evoked 
potential techniques) or estimated hearing ranges (behavioral response 
data, anatomical modeling, etc.). Note that no direct measurements of 
hearing ability have been successfully completed for mysticetes (i.e., 
low-frequency cetaceans). Subsequently, NMFS (2018, 2024) 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.
    On May 3, 2024, NMFS published and solicited public comment on its 
draft Updated Technical Guidance (89 FR 36762), which includes updated 
hearing ranges and names for the marine mammal hearing groups and is 
intended to replace the 2018 Technical Guidance once finalized. The 
public comment period ended on June 17th, 2024. Because NMFS may 
finalize the Guidance prior to taking a final agency action on this 
proposed rulemaking, we considered both the 2018 and 2024 Technical 
Guidance in our effects and estimated take analysis below. Marine 
mammal hearing groups and their associated hearing ranges from NMFS 
(2018) and NMFS (2024) are provided in tables 5 and 6. In the draft 
Updated

[[Page 85706]]

Technical Guidance, mid-frequency cetaceans have been re-classified as 
high-frequency cetaceans, and high-frequency cetaceans have been 
updated to very-high-frequency (VHF) cetaceans. Additionally, the draft 
Updated Technical Guidance includes in-air data for phocid (PA) and 
otariid (OA) pinnipeds.

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


                  Table 6--Marine Mammal Hearing Groups
                               [NMFS 2024]
------------------------------------------------------------------------
            Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Underwater:
    Low-frequency (LF) cetaceans       7 Hz to 36 kHz.
     (baleen whales).
    High-frequency (HF) cetaceans      150 Hz to 160 kHz.
     (dolphins, toothed whales,
     beaked whales, bottlenose
     whales).
    Very High-frequency (VHF)          200 Hz to 165 kHz.
     cetaceans (true porpoises,
     Kogia, river dolphins,
     Cephalorhynchid, Lagenorhynchus
     cruciger & L. australis).
    Phocid pinnipeds (PW)              40 Hz to 90 kHz.
     (underwater) (true seals).
    Otariid pinnipeds (OW)             60 Hz to 68 kHz.
     (underwater) (sea lions and fur
     seals).
In-air:
    Phocid pinnipeds (PA) (true        42 Hz to 52 kHz.
     seals).
    Otariid pinnipeds (OA) (sea lions  90 Hz to 40 kHz.
     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 may not be as broad. Generalized hearing range
  chosen based on ~65 dB threshold from composite audiogram, previous
  analysis in NMFS 2018, and/or data from Southall et al. 2007; Southall
  et al. 2019. Additionally, animals are able to detect very loud sounds
  above and below that ``generalized'' hearing range

    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2018, 2024) for a review of available 
information.

Potential Effects of the Specified Activity on Marine Mammals and Their 
Habitat

    This section provides a discussion of the ways in which components 
of the specified activity may impact marine mammals and their habitat. 
The Estimated Take of Marine Mammals section later in this document 
includes a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The Negligible Impact Analysis 
and Determination section considers the content of this section, the 
Estimated Take of Marine Mammals section, and the Proposed Mitigation 
section, to draw conclusions regarding the likely impacts of these 
activities on the reproductive success or survivorship of individuals 
and whether those impacts are reasonably likely to, adversely affect 
the species or stock through effects on annual rates of recruitment or 
survival.
    Acoustic effects on marine mammals during the specified activities 
are expected to potentially occur from vibratory pile installation and 
removal and impact pile installation. The effects of underwater noise 
from the POA's proposed activities have the potential to result in 
Level B harassment of marine mammals in the project area and, for some 
species as a result of certain activities, Level A harassment.

Background on Sound

    This section contains a brief technical background on sound, on the 
characteristics of certain sound types and on metrics used relevant to 
the specified activity and to a discussion of the potential effects of 
the specified activities on marine mammals found later in this 
document. For general information on sound and its interaction with the 
marine environment, please see: Erbe and Thomas (2022); Au and Hastings 
(2008); Richardson et al. (1995); Urick (1983); as well as the 
Discovery of Sound in the Sea website at https://dosits.org/.
    Sound is a vibration that travels as an acoustic wave through a 
medium such as a gas, liquid or solid. Sound waves alternately compress 
and decompress the medium as the wave travels. In water, sound waves 
radiate in a manner similar to ripples on the surface of a pond and may 
be either directed in a beam (narrow beam or directional sources) or 
sound may radiate in all directions (omnidirectional sources), as is 
the case for sound produced by the construction activities considered 
here. The compressions and decompressions associated with sound waves 
are detected as changes in pressure by marine mammals and human-made 
sound receptors such as hydrophones.
    Sound travels more efficiently in water than almost any other form 
of energy, making the use of sound as a primary sensory modality ideal 
for inhabitants of the aquatic environment. In seawater, sound travels 
at roughly 1,500 meters per second (m/s). In air, sound waves travel 
much more slowly at about 340 m/s. However, the speed of sound in water 
can vary by a small amount based on characteristics of the

[[Page 85707]]

transmission medium such as temperature and salinity.
    The basic characteristics of a sound wave are frequency, 
wavelength, velocity, and amplitude. Frequency is the number of 
pressure waves that pass by a reference point per unit of time and is 
measured in hertz (Hz) or cycles per second. Wavelength is the distance 
between two peaks or corresponding points of a sound wave (length of 
one cycle). Higher frequency sounds have shorter wavelengths than lower 
frequency sounds, and typically attenuate (decrease) more rapidly with 
distance. The amplitude of a sound pressure wave is related to the 
subjective ``loudness'' of a sound and is typically expressed in dB, 
which are a relative unit of measurement that is used to express the 
ratio of one value of a power or pressure to another. A sound pressure 
level (SPL) in dB is described as the ratio between a measured pressure 
and a reference pressure, and is a logarithmic unit that accounts for 
large variations in amplitude; therefore, a relatively small change in 
dB corresponds to large changes in sound pressure. For example, a 10-dB 
increase is a ten-fold increase in acoustic power. A 20-dB increase is 
then a 100-fold increase in power and a 30-dB increase is a 1,000-fold 
increase in power. However, a ten-fold increase in acoustic power does 
not mean that the sound is perceived as being 10 times louder due to 
the anatomy of mammalian ears. A 10-dB increase in sound is perceived 
as a doubling of loudness to the human ear, and marine mammal studies 
of loudness perception are ongoing (Houser et al. 2017).
    The dB is a relative unit comparing two pressures; therefore, a 
reference pressure must always be indicated. For underwater sound, this 
is 1 microPascal ([mu]Pa). For in-air sound, the reference pressure is 
20 microPascal ([mu]Pa). The amplitude of a sound can be presented in 
various ways; however, NMFS typically considers three metrics: sound 
exposure level (SEL), root-mean-square (RMS) SPL, and peak SPL (defined 
below). The source level represents the SPL referenced at a standard 
distance from the source, typically 1 m (Richardson et al., 1995; 
American National Standards Institute (ANSI, 2013), while the received 
level is the SPL at the receiver's position. For pile driving 
activities, the SPL is typically referenced at 10 m.
    SEL (represented as dB referenced to 1 micropascal squared second 
(re 1 [mu]Pa\2\-s)) represents the total energy in a stated frequency 
band over a stated time interval or event, and considers both intensity 
and duration of exposure. The per-pulse SEL (e.g., single strike or 
single shot SEL) is calculated over the time window containing the 
entire pulse (i.e., 100 percent of the acoustic energy). SEL can also 
be a cumulative metric; it can be accumulated over a single pulse (for 
pile driving this is the same as single-strike SEL, above; 
SEL<INF>ss</INF>), or calculated over periods containing multiple 
pulses (SEL<INF>cum</INF>). Cumulative SEL (SEL<INF>cum</INF>) 
represents the total energy accumulated by a receiver over a defined 
time window or during an event. The SEL metric is useful because it 
allows sound exposures of different durations to be related to one 
another in terms of total acoustic energy. The duration of a sound 
event and the number of pulses, however, should be specified as there 
is no accepted standard duration over which the summation of energy is 
measured.
    RMS SPL is equal to 10 times the logarithm (base 10) of the ratio 
of the mean-square sound pressure to the specified reference value, and 
given in units of dB (International Organization for Standardization 
(ISO), 2017). RMS is calculated by squaring all of the sound 
amplitudes, averaging the squares, and then taking the square root of 
the average (Urick, 1983). RMS accounts for both positive and negative 
values; squaring the pressures makes all values positive so that they 
may be accounted for in the summation of pressure levels (Hastings and 
Popper, 2005). This measurement is often used in the context of 
discussing behavioral effects, in part because behavioral effects, 
which often result from auditory cues, may be better expressed through 
averaged units than by peak SPL. For impulsive sounds, RMS is 
calculated by the portion of the waveform containing 90 percent of the 
sound energy from the impulsive event (Madsen, 2005).
    Peak SPL (also referred to as zero-to-peak sound pressure or 0-pk) 
is the maximum instantaneous sound pressure measurable in the water, 
which can arise from a positive or negative sound pressure, during a 
specified time, for a specific frequency range at a specified distance 
from the source, and is represented in the same units as the RMS sound 
pressure (ISO, 2017). Along with SEL, this metric is used in evaluating 
the potential for permanent threshold shift (PTS) and temporary 
threshold shift (TTS) associated with impulsive sound sources.
    Sounds are also characterized by their temporal components. 
Continuous sounds are those whose sound pressure level remains above 
that of the ambient or background sound with negligibly small 
fluctuations in level (ANSI, 2005) while intermittent sounds are 
defined as sounds with interrupted levels of low or no sound (National 
Institute for Occupational Safety and Health (NIOSH), 1998). A key 
distinction between continuous and intermittent sound sources is that 
intermittent sounds have a more regular (predictable) pattern of bursts 
of sounds and silent periods (i.e., duty cycle), which continuous 
sounds do not.
    Sounds may be either impulsive or non-impulsive (defined below). 
The distinction between these two sound types is important because they 
have differing potential to cause physical effects, particularly with 
regard to noise-induced hearing loss (e.g., Ward, 1997 in Southall et 
al., 2007). Please see NMFS (2018) and Southall et al. (2007, 2019) for 
an in-depth discussion of these concepts.
    Impulsive sound sources (e.g., explosions, gunshots, sonic booms, 
seismic airgun shots, impact pile driving) produce signals that are 
brief (typically considered to be less than 1 second), broadband, 
atonal transients (ANSI, 1986, 2005; NIOSH, 1998) and occur either as 
isolated events or repeated in some succession. Impulsive sounds are 
all characterized by a relatively rapid rise from ambient pressure to a 
maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features. Impulsive 
sounds are intermittent in nature. The duration of such sounds, as 
received at a distance, can be greatly extended in a highly reverberant 
environment.
    Non-impulsive sounds can be tonal, narrowband, or broadband, brief 
or prolonged, and may be either continuous or non-continuous (i.e., 
intermittent) (ANSI, 1995; NIOSH, 1998). Some of these non-impulsive 
sounds can be transient signals of short duration but without the 
essential properties of impulses (e.g., rapid rise time). Examples of 
non-impulsive sounds include those produced by vessels, aircraft, 
machinery operations such as drilling or dredging, vibratory pile 
driving, and active sonar systems.
    Even in the absence of sound from the specified activity, the 
underwater environment is characterized by sounds from both natural and 
anthropogenic sound sources. Ambient sound is defined as a composite of 
naturally-occurring (i.e., non-anthropogenic) sound from many sources 
both near and far (ANSI, 1995). Background sound is similar but 
includes all sounds, including anthropogenic sounds minus

[[Page 85708]]

the sound produced by the proposed activities (NMFS, 2012, 2016a). The 
sound level of a region is defined by the total acoustical energy being 
generated by known and unknown sources. These sources may include 
physical (e.g., wind and waves, earthquakes, ice, atmospheric sound), 
biological (e.g., sounds produced by marine mammals, fish, and 
invertebrates), and anthropogenic (e.g., vessels, dredging, 
construction) sound. A number of sources contribute to background and 
ambient sound, including wind and waves, which are a main source of 
naturally occurring ambient sound for frequencies between 200 Hz and 50 
kilohertz (kHz) (Mitson, 1995). In general, background and ambient 
sound levels tend to increase with increasing wind speed and wave 
height. Precipitation can become an important component of total sound 
at frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times. Marine mammals can contribute significantly to background and 
ambient sound levels, as can some fish and snapping shrimp. The 
frequency band for biological contributions is from approximately 12 Hz 
to over 100 kHz. Sources of background sound related to human activity 
include transportation (surface vessels), dredging and construction, 
oil and gas drilling and production, geophysical surveys, sonar, and 
explosions. Vessel noise typically dominates the total background sound 
for frequencies between 20 and 300 Hz. In general, the frequencies of 
many anthropogenic sounds, particularly those produced by construction 
activities, are below 1 kHz (Richardson et al., 1995). When sounds at 
frequencies greater than 1 kHz are produced, they generally attenuate 
relatively rapidly (Richardson et al., 1995), particularly above 20 kHz 
due to propagation losses and absorption (Urick, 1983).
    Transmission loss (TL) defines the degree to which underwater sound 
has spread in space and lost energy after having moved through the 
environment and reached a receiver. It is defined by the ISO as the 
reduction in a specified level between two specified points that are 
within an underwater acoustic field (ISO, 2017). Careful consideration 
of transmission loss and appropriate propagation modeling is a crucial 
step in determining the impacts of underwater sound, as it helps to 
define the ranges (isopleths) to which impacts are expected and depends 
significantly on local environmental parameters such as seabed type, 
water depth (bathymetry), and the local speed of sound. Geometric 
spreading laws are powerful tools which provide a simple means of 
estimating TL, based on the shape of the sound wave front in the water 
column. For a sound source that is equally loud in all directions and 
in deep water, the sound field takes the form of a sphere, as the sound 
extends in every direction uniformly. In this case, the intensity of 
the sound is spread across the surface of the sphere, and thus we can 
relate intensity loss to the square of the range (as area = 4*pi*r\2\). 
This can be expressed logarithmically, where TL = 
20*Log<INF>10</INF>(range). This situation is known as spherical 
spreading. In shallow water, the sea surface and seafloor will bound 
the shape of the sound wave, leading to a more cylindrical shape, as 
the top and bottom of the sphere is truncated by the largely reflective 
boundaries. This situation is termed cylindrical spreading, and is 
given by TL = 10*Log<INF>10</INF>(range) (Urick, 1983). An intermediate 
scenario may be defined by the equation TL = 
15*Log<INF>10</INF>(range), and is referred to as practical spreading. 
Though these geometric spreading scenarios do not capture many often 
important details (scattering, absorption, etc.), they offer a 
reasonable and simple approximation of how sound decreases in intensity 
as it is transmitted. In the absence of measured data indicating the 
level of transmission loss at a given site for a specific activity, 
NMFS recommends practical spreading (i.e., TL = 
15*Log<INF>10</INF>(range)) to model acoustic propagation for 
construction activities in most nearshore environments.
    The sum of the various natural and anthropogenic sound sources at 
any given location and time depends not only on the source levels, but 
also on the propagation of sound through the environment. Sound 
propagation is dependent on the spatially and temporally varying 
properties of the water column and sea floor, and is frequency-
dependent. As a result of the dependence on a large number of varying 
factors, background and ambient sound levels can be expected to vary 
widely over both coarse and fine spatial and temporal scales. Sound 
levels at a given frequency and location can vary by 10 to 20 dB from 
day to day (Richardson et al., 1995). The result is that, depending on 
the source type and its intensity, sound from the specified activity 
may be a negligible addition to the local environment or could form a 
distinctive signal that may affect marine mammals.
    Background underwater noise levels in the CTR Project area are both 
variable and relatively high, primarily because of extreme tidal 
activity, elevated sediment loads in the water column, periodic high 
winds, the seasonal presence of ice, and anthropogenic activities. 
Sources of anthropogenic noise in the CTR Project area consist of 
dredging operations, boats, ships, oil and gas operations, construction 
noise, and aircraft overflights from JBER and Ted Stevens International 
Airport, all of which contribute to high underwater noise levels in 
upper Cook Inlet (e.g., Blackwell and Greene, 2002; (Knik Arm Bridge 
and Toll Authority (KABATA), 2011; Castellote et al., 2018).
    Background sound levels were measured at the POA during the PAMP 
2016 Test Pile Program (TPP) in the absence of pile driving at two 
locations during a 3[hyphen]day break in pile installation. Median 
background noise levels, measured at a location just offshore of the 
POA SFD and at a second location about 1 km offshore, were 117 and 
122.2 dB RMS, respectively (Austin et al., 2016). NMFS considers the 
median sound levels to be most appropriate when considering background 
noise levels for purposes of evaluating the potential impacts of the 
proposed project on marine mammals (NMFS, 2012). By using the median 
value, which is the 50th percentile of the measurements, for background 
noise levels, 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 2 of the 4 days (50 percent) 
when background measurement data were being collected, the USACE 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 2 days of data collection, no dredging occurred. 
Therefore, the median provides a better representation of background 
noise levels when the CTR project would be occurring. During the 
measurements, some typical sound signals were noted, such as noise from 
current flow and the passage of vessels.
    With regard to spatial considerations of the measurements, the 
offshore location is most applicable to assessing background sound 
during the CTR project (NMFS, 2012). The median background noise level 
measured at the offshore hydrophone was 122.2 dB RMS. The measurement 
location closer to the POA was quieter, with a median of 117 dB; 
however, that hydrophone was placed very close to a dock. During PCT 
acoustic monitoring, noise levels in Knik Arm absent pile driving were 
also collected (Illingworth & Rodkin (I&R), 2021a, 2022b)); however, 
the PCT IHAs did not require background noise

[[Page 85709]]

measurements to be collected in adherence with NMFS (2012) 
methodological recommendations. Despite this, the noise levels measured 
during the PCT project were not significantly different from 122.2 dB 
(I&R, 2021a, 2022b). If additional background data are collected in the 
future in this region, NMFS may re-evaluate the data to appropriately 
characterize background sound levels in Knik Arm.

Description of Sound Sources for the Specified Activities

    In-water construction activities associated with the project that 
have the potential to incidentally take marine mammals through exposure 
to sound would include impact pile installation and vibratory pile 
installation and removal. Impact hammers typically operate by 
repeatedly dropping and/or pushing a heavy piston onto a pile to drive 
the pile into the substrate. Sound generated by impact hammers is 
impulsive, characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper, 2005). 
Vibratory hammers install piles by vibrating them and allowing the 
weight of the hammer to push them into the sediment. Vibratory hammers 
typically produce less sound (i.e., lower levels) than impact hammers. 
Peak SPLs may be 180 dB or greater but are generally 10 to 20 dB lower 
than SPLs generated during impact pile driving of the same-sized pile 
(Oestman et al., 2009; California Department of Transportation 
(CALTRANS), 2015, 2020). Sounds produced by vibratory hammers are non-
impulsive; the rise time is slower, reducing the probability and 
severity of injury, and the sound energy is distributed over a greater 
amount of time (Nedwell and Edwards, 2002; Carlson et al., 2005).
    The likely or possible impacts of the POA's proposed activities on 
marine mammals could involve both non-acoustic and acoustic stressors. 
Potential non-acoustic stressors could result from the physical 
presence of the equipment and personnel; however, given there are no 
known pinniped haul-out sites in the vicinity of the CTR project site, 
visual and other non-acoustic stressors would be limited, and any 
impacts to marine mammals are expected to primarily be acoustic in 
nature.

Acoustic Impacts

    The introduction of anthropogenic noise into the aquatic 
environment from pile driving is the primary means by which marine 
mammals may be harassed from the POA's specified activity. In general, 
animals exposed to natural or anthropogenic sound may experience 
physical and psychological effects, ranging in magnitude from none to 
severe (Southall et al., 2007, 2019). Exposure to pile driving noise 
has the potential to result in auditory threshold shifts and behavioral 
reactions (e.g., avoidance, temporary cessation of foraging and 
vocalizing, changes in dive behavior). Exposure to anthropogenic noise 
can also lead to non-observable physiological responses, such as an 
increase in stress hormones. Additional noise in a marine mammal's 
habitat can mask acoustic cues used by marine mammals to carry out 
daily functions, such as communication and predator and prey detection. 
The effects of pile driving noise on marine mammals are dependent on 
several factors, including, but not limited to, sound type (e.g., 
impulsive vs. non-impulsive), the species, age and sex class (e.g., 
adult male vs. mom with calf), duration of exposure, the distance 
between the pile and the animal, received levels, behavior at time of 
exposure, and previous history with exposure (Wartzok et al., 2004; 
Southall et al., 2007). Here, we discuss physical auditory effects 
(threshold shifts) followed by behavioral effects and potential impacts 
on habitat.
    NMFS defines a noise-induced threshold shift (TS) as a change, 
usually an increase, in the threshold of audibility at a specified 
frequency or portion of an individual's hearing range above a 
previously established reference level (NMFS, 2018). The amount of 
threshold shift is customarily expressed in dB. A TS can be permanent 
or temporary. As described in NMFS (2018, 2024) 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 
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).
    Auditory Injury and Permanent Threshold Shift (PTS). NMFS defines 
auditory injury as ``damage to the inner ear that can result in 
destruction of tissue . . . which may or may not result in PTS'' (NMFS, 
2024). 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, 2024). PTS does not generally affect more than a limited 
frequency range, and an animal that has incurred PTS has incurred some 
level of hearing loss at the relevant frequencies; typically, animals 
with PTS are not functionally deaf (Au and Hastings, 2008; Finneran, 
2016). Available data from humans and other terrestrial mammals 
indicate that a 40-dB threshold shift approximates PTS onset (see Ward 
et al., 1958, 1959, 1960; Kryter et al., 1966; Miller, 1974; Ahroon et 
al., 1996; Henderson et al., 2008). PTS levels for marine mammals are 
estimates, as with the exception of a single study unintentionally 
inducing PTS in a harbor seal (Kastak et al., 2008), there are no 
empirical data measuring PTS in marine mammals largely due to the fact 
that, for various ethical reasons, experiments involving anthropogenic 
noise exposure at levels inducing PTS are not typically pursued or 
authorized (NMFS, 2018).
    Temporary Threshold Shift (TTS). 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 marine mammal TTS measurements 
(see Southall et al., 2007, 2019), 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 (Finneran et 
al., 2000, 2002; Schlundt et al., 2000). As described in Finneran 
(2015), marine mammal studies have shown the amount of TTS increases 
with SEL<INF>cum</INF> in an accelerating fashion: at low exposures 
with lower SEL<INF>cum</INF>, the amount of TTS is typically small and 
the growth curves have shallow slopes. At exposures with higher 
SEL<INF>cum</INF>, the growth curves become steeper and approach linear 
relationships with the noise SEL.
    Depending on the degree (elevation of threshold in dB), duration 
(i.e., recovery time), and frequency range of TTS, and the context in 
which it is experienced, TTS can have effects on marine mammals ranging 
from discountable to serious (similar to those discussed in auditory 
masking, below). For example, a marine mammal may be able to readily 
compensate for a brief, relatively small amount of TTS in a non-
critical frequency range that takes place during

[[Page 85710]]

a time when the animal is traveling through the open ocean, where 
ambient noise is lower and there are not as many competing sounds 
present. Alternatively, a larger amount and longer duration of TTS 
sustained during time when communication is critical for successful 
mother/calf interactions could have more serious impacts. We note that 
reduced hearing sensitivity as a simple function of aging has been 
observed in marine mammals, as well as humans and other taxa (Southall 
et al., 2007), so we can infer that strategies exist for coping with 
this condition to some degree, though likely not without cost.
    Many studies have examined noise-induced hearing loss in marine 
mammals (see Finneran (2015) and Southall et al. (2019) for summaries). 
TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 2013). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. For 
cetaceans, published data on the onset of TTS are limited to captive 
bottlenose dolphin (Tursiops truncatus), beluga whale, harbor porpoise, 
and Yangtze finless porpoise (Neophocoena asiaeorientalis) (Southall et 
al., 2019). For pinnipeds in water, measurements of TTS are limited to 
harbor seals, elephant seals (Mirounga angustirostris), bearded seals 
(Erignathus barbatus) and California sea lions (Zalophus californianus) 
(Kastak et al., 1999, 2007; Kastelein et al., 2019b, 2019c, 2021, 
2022a, 2022b; Reichmuth et al., 2019; Sills et al., 2020). TTS was not 
observed in spotted (Phoca largha) and ringed (Pusa hispida) seals 
exposed to single airgun impulse sounds at levels matching previous 
predictions of TTS onset (Reichmuth et al., 2016). These studies 
examine hearing thresholds measured in marine mammals before and after 
exposure to intense or long-duration sound exposures. The difference 
between the pre-exposure and post-exposure thresholds can be used to 
determine the amount of threshold shift at various post-exposure times.
    The amount and onset of TTS depends on the exposure frequency. 
Sounds at low frequencies, well below the region of best sensitivity 
for a species or hearing group, are less hazardous than those at higher 
frequencies, near the region of best sensitivity (Finneran and 
Schlundt, 2013). At low frequencies, onset-TTS exposure levels are 
higher compared to those in the region of best sensitivity (i.e., a low 
frequency noise would need to be louder to cause TTS onset when TTS 
exposure level is higher), as shown for harbor porpoises and harbor 
seals (Kastelein et al., 2019a, 2019c). Note that in general, harbor 
seals and harbor porpoises have a lower TTS onset than other measured 
pinniped or cetacean species (Finneran, 2015). In addition, TTS can 
accumulate across multiple exposures, but the resulting TTS will be 
less than the TTS from a single, continuous exposure with the same SEL 
(Mooney et al., 2009; Finneran et al., 2010; Kastelein et al., 2014, 
2015). This means that TTS predictions based on the total, cumulative 
SEL will overestimate the amount of TTS from intermittent exposures, 
such as sonars and impulsive sources. Nachtigall et al. (2018) describe 
measurements of hearing sensitivity of multiple odontocete species 
(bottlenose dolphin, harbor porpoise, beluga, and false killer whale 
(Pseudorca crassidens)) when a relatively loud sound was preceded by a 
warning sound. These captive animals were shown to reduce hearing 
sensitivity when warned of an impending intense sound. Based on these 
experimental observations of captive animals, the authors suggest that 
wild animals may dampen their hearing during prolonged exposures or if 
conditioned to anticipate intense sounds. Another study showed that 
echolocating animals (including odontocetes) might have anatomical 
specializations that might allow for conditioned hearing reduction and 
filtering of low-frequency ambient noise, including increased stiffness 
and control of middle ear structures and placement of inner ear 
structures (Ketten et al., 2021). Data available on noise-induced 
hearing loss for mysticetes are currently lacking (NMFS, 2018). 
Additionally, the existing marine mammal TTS data come from a limited 
number of individuals within these species.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans. However, 
such relationships are assumed to be similar to those in humans and 
other terrestrial mammals. PTS typically occurs at exposure levels at 
least several dB above that inducing mild TTS (e.g., a 40-dB threshold 
shift approximates PTS onset (Kryter et al., 1966; Miller, 1974), while 
a 6-dB threshold shift approximates TTS onset (Southall et al., 2007, 
2019). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulsive sounds (such as 
impact pile driving pulses as received close to the source) are at 
least 6 dB higher than the TTS threshold on a peak-pressure basis, and 
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level thresholds (Southall et al., 
2007, 2019). Given the higher level of sound or longer exposure 
duration necessary to cause PTS as compared with TTS, it is 
considerably less likely that PTS could occur.
    Behavioral Harassment. Exposure to noise also has the potential to 
behaviorally disturb marine mammals to a level that rises to the 
definition of harassment under the MMPA. Generally speaking, NMFS 
considers a behavioral disturbance that rises to the level of 
harassment under the MMPA a non-minor response--in other words, not 
every response qualifies as behavioral disturbance, and for responses 
that do, those of a higher level, or accrued across a longer duration, 
have the potential to affect foraging, reproduction, or survival. 
Behavioral disturbance may include a variety of effects, including 
subtle changes in behavior (e.g., minor or brief avoidance of an area 
or changes in vocalizations), more conspicuous changes in similar 
behavioral activities, and more sustained and/or potentially severe 
reactions, such as displacement from or abandonment of high-quality 
habitat. Behavioral responses may include changing durations of 
surfacing and dives; changing direction and/or speed; reducing/
increasing vocal activities; changing/cessation of certain behavioral 
activities (such as socializing or feeding); eliciting a visible 
startle response or aggressive behavior (such as tail/fin slapping or 
jaw clapping); avoidance of areas where sound sources are located. 
Pinnipeds may increase their haul out time, possibly to avoid in-water 
disturbance (Thorson and Reyff, 2006).
    Behavioral responses to sound are highly variable and context-
specific and any reactions depend on numerous intrinsic and extrinsic 
factors (e.g., species, state of maturity, experience, current 
activity, reproductive state, auditory sensitivity, time of day), as 
well as the interplay between factors (e.g., Richardson et al., 1995; 
Wartzok et al., 2004; Southall et al., 2007, 2019; Weilgart, 2007; 
Archer et al., 2010, Erbe et al., 2019). 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

[[Page 85711]]

vary depending on characteristics associated with the sound source 
(e.g., whether it is moving or stationary, number of sources, distance 
from the source). In general, pinnipeds seem more tolerant of, or at 
least habituate more quickly to, potentially disturbing underwater 
sound than do cetaceans and generally seem to be less responsive to 
exposure to industrial sound than most cetaceans. Please see appendices 
B and C of Southall et al. (2007) and Gomez et al. (2016) for reviews 
of studies involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2004). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure.
    As noted above, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; Wartzok et al., 2004; National Research Council (NRC), 2005). 
Controlled experiments with captive marine mammals have showed 
pronounced behavioral reactions, including avoidance of loud sound 
sources (Ridgway et al., 1997; Finneran et al., 2003). Observed 
responses of wild marine mammals to loud pulsed sound sources (e.g., 
seismic airguns) have been varied but often consist of avoidance 
behavior or other behavioral changes (Richardson et al., 1995; Morton 
and Symonds, 2002; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal (e.g., Erbe et al., 2019). 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, 2013b, Blair et al., 2016). 
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. However, acoustic and movement bio-logging tools have been 
used in some cases, to infer responses of feeding to anthropogenic 
noise. For example, Blair et al. (2016) reported significant effects on 
humpback whale foraging behavior in Stellwagen Bank in response to ship 
noise including slower descent rates, and fewer side-rolling events per 
dive with increasing ship nose. In addition, Wisniewska et al. (2018) 
reported that tagged harbor porpoises demonstrated fewer prey capture 
attempts when encountering occasional high-noise levels resulting from 
vessel noise as well as more vigorous fluking, interrupted foraging, 
and cessation of echolocation signals observed in response to some 
high-noise vessel passes.
    In response to playbacks of vibratory pile driving sounds, captive 
bottlenose dolphins showed changes in target detection and number of 
clicks used for a trained echolocation task (Branstetter et al. 2018). 
Similarly, harbor porpoises trained to collect fish during playback of 
impact pile driving sounds also showed potential changes in behavior 
and task success, though individual differences were prevalent 
(Kastelein et al. 2019d). 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 
relationships among prey availability, foraging effort and success, and 
the life history stage(s) of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et 
al., 2007). For example, harbor porpoise' respiration rate increased in 
response to pile driving sounds at and above a received broadband SPL 
of 136 dB (zero-peak SPL: 151 dB re 1 [mu]Pa; SEL of a single strike: 
127 dB re 1 [mu]Pa\2\-s) (Kastelein et al., 2013).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). In response to construction noise from offshore wind farms, 
harbor porpoises and harbor seals have demonstrated avoidance on the 
scale of hours to weeks (Brandt et al., 2018; Russell et al., 2016). 
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

[[Page 85712]]

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; Bowers et al., 2018). The result of a flight response 
could range from brief, temporary exertion and displacement from the 
area where the signal provokes flight to, in extreme cases, marine 
mammal strandings (England et al., 2001). However, it should be noted 
that response to a perceived predator does not necessarily invoke 
flight (Ford and Reeves, 2008), and whether individuals are solitary or 
in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fishes and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; 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 5-day period did not cause any sleep 
deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than 1 day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive (i.e., meaningful) behavioral reactions and multi-day 
anthropogenic activities. For example, just because an activity lasts 
for multiple days does not necessarily mean that individual animals are 
either exposed to activity-related stressors for multiple days or, 
further, exposed in a manner resulting in sustained multi-day 
substantive behavioral responses.
    Behavioral Reactions Observed at the POA. Specific to recent 
construction at the POA, behavioral reactions to pile driving have not 
been reported in non-CIBW species. During POA's PCT construction, 81 
harbor seals were observed within estimated Level B harassment zones 
associated with vibratory and impact installation and removal of 36-in 
(61-cm) and 144-in (366-cm) piles, and 5 harbor seals were observed 
within estimated Level A harassment zones during the installation of 
144-in (366-cm) piles. No observable behavioral reactions were observed 
in any of these seals (61N Environmental, 2021, 2022a). One harbor 
porpoise was observed within the estimated Level B harassment zone 
during vibratory driving of a 36-in (61-cm) pile in May 2021. The 
animal was traveling at a moderate pace. No observable reactions to 
pile driving were noted by the PSOs. Another harbor porpoise near the 
border of (and may have been within) the estimated Level B harassment 
zone during the impact installation of 36-in (61-cm) piles in June 
2021, but PSOs did not record any behavioral responses of this 
individual to the pile driving activities. Similarly 13 harbor seals 
observed within estimated Level B harassment zones associated with pile 
driving 36-in (61-cm) piles during POA's SFD construction did not 
exhibit observable behavioral reactions (61N Environmental, 2022b).
    Specific to CIBWs, several years of marine mammal monitoring data 
demonstrate behavioral responses to pile driving at the POA. Previous 
pile driving activities at the POA include the installation and removal 
of sheet piles, the vibratory and impact installation of 24-in (61-cm), 
36-in (91-cm), 48-in (122-cm), and 144-in (366-cm) pipe piles, and the 
vibratory installation of 72-in (182-cm) air bubble casings.
    Kendall and Cornick (2015) provide a comprehensive overview of 4 
years of scientific marine mammal monitoring conducted before (2005-
2006) and during the POA's MTRP (2008-2009). These were observations 
made by biologists at Alaska Pacific University, funded by the POA and 
other groups but independent of the POA's required monitoring for pile 
driving activities (i.e., not construction based PSOs). The authors 
investigated CIBW 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 hours of sampling effort was 
completed across 349 days 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 <plus-minus> 0.01) and during (n = 
13; 0.01 <plus-minus> 0.03) pile driving were not significantly 
different. However, sighting duration of CIBWs decreased significantly 
during pile driving (39 <plus-minus> 6 min before and 18 <plus-minus> 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. Documentation of 
milling was observed on 21 occasions during pile driving. Mean group 
size decreased during pile driving; however, this difference was not 
statistically significant. In addition, group composition was 
significantly different before and during pile driving, with more white 
(i.e., likely older) animals being present during pile driving (Kendall 
and Cornick, 2015). CIBWs were primarily observed densely packed before 
and during pile driving; however, the number of densely packed groups 
increased by approximately 67 percent during pile driving. There were 
also significant increases in the number of dispersed groups 
(approximately 81 percent) and lone white whales (approximately 60 
percent) present during pile driving than before pile driving (Kendall 
and Cornick, 2015).
    During PCT and SFD construction monitoring, behaviors of CIBWs 
groups were compared by month and by construction activity (61N 
Environmental, 2021, 2022a, 2022b). Little variability was evident in 
the behaviors recorded from month to month or among sightings that 
coincided with in-water pile installation and removal and those that 
did not (61N Environmental, 2021, 2022a). Definitive behavioral 
reactions to in-water pile

[[Page 85713]]

driving or avoidance behaviors were not documented; however, potential 
reactions (where a group reversed its trajectory shortly after the 
start of in-water pile driving occurred; a group reversed its 
trajectory as it got closer to the sound source during active in-water 
pile driving; or upon an initial sighting, a group was already moving 
away from in-water pile driving, raising the possibility that it had 
been moving towards, but was only sighted after they turned away) and 
instances where CIBWs moved toward active in-water pile driving were 
recorded. During these instances, impact driving appeared to cause 
potential behavioral reactions more readily than vibratory hammering 
(61N Environmental, 2021, 2022a, 2022b). One minor difference 
documented during PCT construction was a slightly higher incidence of 
milling behavior and diving during the periods of no pile driving and 
slightly higher rates of traveling behavior during periods when 
potential CIBW behavioral reactions to pile driving, as described 
above, were recorded (61N Environmental, 2021, 2022a). Note, narratives 
of each CIBW reaction can be found in the appendices of the POA's final 
monitoring reports (61N Environmental, 2021, 2022a, 2022b).
    Acoustically, Saxon-Kendall et al. (2013) recorded echolocation 
clicks (which can be indicative of feeding behavior) during the MTR 
Project at the POA both while pile driving was occurring and when it 
was not. This indicates that while feeding is not a predominant 
behavior that PSOs visually observed in CIBWs sighted near the POA (61N 
Environmental, 2021, 2022a, 2022b, 2022c; Easley-Appleyard and Leonard, 
2022) CIBWs can and still exhibit feeding behaviors during pile driving 
activities. In addition, Castellote et al. (2020) found low 
echolocation detection rates in lower Knik Arm (i.e., Six Mile, Port 
MacKenzie, and Cairn Point) and suggested that CIBWs moved through that 
area relatively quickly when entering or exiting the Arm. No whistles 
or noisy vocalizations were recorded during the MTRP construction 
activities; however, it is possible that persistent noise associated 
with construction activity at the MTR project masked beluga 
vocalizations and or that CIBWs did not use these communicative signals 
when they were near the MTR Project (Saxon-Kendall et al., 2013).
    Recently, McHuron et al. (2023) developed a model to predict 
general patterns related to the movement and foraging decisions of 
pregnant CIBWs in Cook Inlet. They found that the effects of 
disturbance from human activities, such as pile driving activities 
occurring at the POA assuming no mitigation measures, are inextricably 
linked with prey availability. If prey are abundant during the summer 
and early fall and prey during winter is above some critical threshold, 
pregnant CIBWs can likely cope with intermittent disruptions, such as 
those produced by pile driving at the POA (McHuron et al., 2023). 
However, they stress that more information needs to be acquired 
regarding CIBW prey and CIBW body condition, specifically in their 
critical habitat, to better understand possible behavioral responses to 
disturbance.
    Stress responses. An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Selye, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. In 
addition, Lemos et al. (2022) observed a correlation between higher 
levels of fecal glucocorticoid metabolite concentrations (indicative of 
a stress response) and vessel traffic in gray 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, 2005), however 
distress is an unlikely result of this project based on observations of 
marine mammals during previous, similar construction projects.
    Norman (2011) reviewed environmental and anthropogenic stressors 
for CIBWs. Lyamin et al. (2011) determined that the heart rate of a 
beluga whale increases in response to noise, depending on the frequency 
and intensity. Acceleration of heart rate in the beluga whale is the 
first component of the ``acoustic startle response.'' Romano et al. 
(2004) demonstrated that captive beluga whales exposed to high-level 
impulsive sounds (i.e., seismic airgun and/or single pure tones up to 
201 dB RMS) resembling sonar pings showed increased stress hormone 
levels of norepinephrine, epinephrine, and dopamine when TTS was 
reached. Thomas et al. (1990) exposed beluga whales to playbacks of an 
oil-drilling platform in operation (``Sedco 708,'' 40 Hz-20 kHz; source 
level 153 dB). Ambient SPL at ambient conditions in the pool before 
playbacks was 106 dB and 134 to 137 dB RMS during playbacks at the 
monitoring hydrophone across the pool. All cell and platelet counts and 
21 different blood chemicals, including epinephrine and norepinephrine, 
were within normal

[[Page 85714]]

limits throughout baseline and playback periods, and stress response 
hormone levels did not increase immediately after playbacks. The 
difference between the Romano et al. (2004) and Thomas et al. (1990) 
studies could be the differences in the type of sound (seismic airgun 
and/or tone versus oil drilling), the intensity and duration of the 
sound, the individual's response, and the surrounding circumstances of 
the individual's environment. The construction sounds in the Thomas et 
al. (1990) study would be more similar to those of pile installation 
than those in the study investigating stress response to water guns and 
pure tones. Therefore, no more than short-term, low-level hormonal 
stress responses, if any, of beluga whales or other marine mammals are 
expected as a result of exposure to in-water pile installation and 
removal during the CTR project.
    Auditory Masking. Since many marine mammals rely on sound to find 
prey, moderate social interactions, and facilitate mating (Tyack, 
2008), noise from anthropogenic sound sources can interfere with these 
functions but only if the noise spectrum overlaps with the hearing 
sensitivity of the receiving marine mammal (Southall et al., 2007; 
Clark et al., 2009; Hatch et al., 2012). Chronic exposure to excessive, 
though not high-intensity, noise could cause masking at particular 
frequencies for marine mammals that utilize sound for vital biological 
functions (Clark et al., 2009). Acoustic masking is when other noises 
such as from human sources interfere with an animal's ability to 
detect, recognize, or discriminate between acoustic signals of interest 
(e.g., those used for intraspecific communication and social 
interactions, prey detection, predator avoidance, navigation) 
(Richardson et al., 1995; Erbe et al., 2016). Therefore, under certain 
circumstances, marine mammals whose acoustical sensors or environment 
are being severely masked could also be impaired from maximizing their 
performance fitness in survival and reproduction. The ability of a 
noise source to mask biologically important sounds depends on the 
characteristics of both the noise source and the signal of interest 
(e.g., signal-to-noise ratio, temporal variability, direction), in 
relation to each other and to an animal's hearing abilities (e.g., 
sensitivity, frequency range, critical ratios, frequency 
discrimination, directional discrimination, age or TTS hearing loss), 
and existing ambient noise and propagation conditions (Hotchkin and 
Parks, 2013).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003) or vocalizations (Foote et al., 2004), 
respectively, while North Atlantic right whales (Eubalaena glacialis) 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007). Fin whales have also been documented 
lowering the bandwidth, peak frequency, and center frequency of their 
vocalizations under increased levels of background noise from large 
vessels (Castellote et al. 2012). Other alterations to communication 
signals have also been observed. For example, gray whales, in response 
to playback experiments exposing them to vessel noise, have been 
observed increasing their vocalization rate and producing louder 
signals at times of increased outboard engine noise (Dahlheim and 
Castellote, 2016). Alternatively, animals may cease sound production 
during production of aversive signals (Bowles et al., 1994).
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is human-made, it may be considered 
harassment when disrupting or altering critical behaviors. It is 
important to distinguish TTS and PTS, which persist after the sound 
exposure, from masking, which occurs during the sound exposure. Because 
masking (without resulting in TS) is not associated with abnormal 
physiological function, it is not considered a physiological effect but 
rather, a potential behavioral effect (though not necessarily one that 
would be associated with harassment).
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007; Di Iorio and Clark, 2010; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Hotchkin and Parks, 2013). Masking can be 
tested directly in captive species (e.g., Erbe, 2008), but in wild 
populations, it must be either modeled or inferred from evidence of 
masking compensation. There are few studies addressing real-world 
masking sounds likely to be experienced by marine mammals in the wild 
(e.g., Branstetter et al., 2013).
    Marine mammals at or near the proposed CTR project site may be 
exposed to anthropogenic noise, which may be a source of masking. 
Vocalization changes may result from a need to compete with an increase 
in background noise and include increasing the source level, modifying 
the frequency, increasing the call repetition rate of vocalizations, or 
ceasing to vocalize in the presence of increased noise (Hotchkin and 
Parks, 2013). For example, in response to loud noise, beluga whales may 
shift the frequency of their echolocation clicks and communication 
signals, reduce their overall calling rates, and or increase the 
emission of certain call signals to prevent masking by anthropogenic 
noise (Lessage et al., 1999; Tyack, 2000; Eickmeier and Vallarta, 
2022).
    Masking occurs in the frequency band or bands that animals utilize 
and is more likely to occur in the presence of broadband, relatively 
continuous noise sources such as vibratory pile driving. Energy 
distribution of pile driving covers a broad frequency spectrum, and 
sound from pile driving would be within the audible range of pinnipeds 
and cetaceans present in the proposed action area. While some 
construction during the POA's activities may mask some acoustic signals 
that are relevant to the daily behavior of marine mammals, the short-
term duration and limited areas affected make it very unlikely that the 
fitness of individual marine mammals would be impacted.
    Airborne Acoustic Effects. Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with construction 
activities that have

[[Page 85715]]

the potential to cause behavioral harassment, depending on their 
distance from these activities. Airborne noise would primarily be an 
issue for pinnipeds that are swimming or hauled out near the project 
site within the range of noise levels elevated above airborne acoustic 
harassment criteria. Although pinnipeds are known to haul-out regularly 
on man-made objects, we believe that incidents of take resulting solely 
from airborne sound are unlikely given there are no known pinniped 
haulout or pupping sites within the vicinity of the proposed project 
area; the nearest known pinniped haulout is located a minimum of 24 km 
south-southwest of Anchorage for harbor seals. Cetaceans are not 
expected to be exposed to airborne sounds that would result in 
harassment as defined under the MMPA.
    We recognize that pinnipeds in the water could be exposed to 
airborne sound that may result in behavioral harassment when looking 
with their heads above water. Most likely, airborne sound would cause 
behavioral responses similar to those discussed above in relation to 
underwater sound. For instance, anthropogenic sound could cause hauled-
out pinnipeds to exhibit changes in their normal behavior, such as 
reduction in vocalizations or cause them to temporarily abandon the 
area and move further from the source. However, these animals would 
previously have been `taken' because of exposure to underwater sound 
above the behavioral harassment thresholds, which are in all cases 
larger than those associated with airborne sound. Thus, the behavioral 
harassment of these animals is already accounted for in these estimates 
of potential take. Therefore, we do not believe that authorization of 
incidental take resulting from airborne sound for pinnipeds is 
warranted, and airborne sound is not discussed further here.

Potential Effects on Marine Mammal Habitat

    The proposed project would occur mostly within the same footprint 
as existing marine infrastructure; the new T1 and T2 would extend 
approximately 140 ft (47-m) seaward of the existing terminals. The 
nearshore and intertidal habitat where the proposed project will occur 
is an area of relatively high marine vessel traffic. Temporary, 
intermittent habitat alteration may result from increased noise levels 
during the proposed construction activities. Noise from impact and 
vibratory pile driving may extend across Knik Arm, and affect areas 
outside of the area around POA excluded from designated CIBW Critical 
Habitat. However, increased noise levels will only be present during 
construction activities and will cease when pile driving ends. Pile 
driving is not expected on all days during the construction season 
(April-November) and is not expected at all during the months of 
December-March. Noise exposure is, therefore, expected to be temporary 
and intermittent with long periods of typical background noise levels 
on a daily and seasonal scale. Effects to CIBW critical habitat are, 
therefore, considered to be non-significant. Effects on prey species 
will be limited in time and space. The long-term impact on marine 
mammal habitat associated with CTR would be a small permanent decrease 
in low-quality potential habitat because of the expanded footprint of 
the new cargo terminals T1 and T2. Installation and removal of in-water 
piles would be temporary and intermittent, and the increased footprint 
of the facilities would destroy only a small amount of low-quality 
habitat, which currently experiences high levels of anthropogenic 
activity.
    Water quality--Temporary and localized reduction in water quality 
would occur as a result of in-water construction activities. Most of 
this effect would occur during the installation and removal of piles 
when bottom sediments are disturbed. The installation and removal of 
piles would disturb bottom sediments and may cause a temporary increase 
in suspended sediment in the project area. During pile removal, 
sediment attached to the pile moves vertically through the water column 
until gravitational forces cause it to slough off under its own weight. 
The small resulting sediment plume is expected to settle out of the 
water column within a few hours. Studies of the effects of turbid water 
on fish (marine mammal prey) suggest that concentrations of suspended 
sediment can reach thousands of milligrams per liter before an acute 
toxic reaction is expected (Burton, 1993).
    Effects to turbidity and sedimentation are expected to be short-
term, minor, and localized. Since the currents are so strong in the 
area, following the completion of sediment-disturbing activities, 
suspended sediments in the water column should dissipate and quickly 
return to background levels in all construction scenarios. Turbidity 
within the water column has the potential to reduce the level of oxygen 
in the water and irritate the gills of prey fish species in the 
proposed project area. However, turbidity plumes associated with the 
project would be temporary and localized, and fish in the proposed 
project area would be able to move away from and avoid the areas where 
plumes may occur. Thus, it is expected that the impacts on prey fish 
species from turbidity and therefore, on marine mammals, would be 
minimal and temporary. In general, the area likely impacted by the 
proposed construction activities is relatively small compared to the 
available marine mammal habitat in Knik Arm, and does not include any 
areas of particular importance.
    Potential Effects on Prey. Sound may affect marine mammals through 
impacts on the abundance, behavior, or distribution of prey species 
(e.g., crustaceans, cephalopods, fishes, zooplankton). Marine mammal 
prey varies by species, season, and location and, for some, is not well 
documented. Studies regarding the effects of noise on known marine 
mammal prey are described here.
    Fishes utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fishes hear sounds using pressure and 
particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds that are especially high amplitude and/or 
intermittent at low frequencies. Short duration, sharp sounds can cause 
overt or subtle changes in fish behavior and local distribution. The 
reaction of fish to noise depends on the physiological state of the 
fish, past exposures, motivation (e.g., feeding, spawning, migration), 
and other environmental factors. 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 fishes (e.g. Scholik and Yan, 2001, 2002; Popper and 
Hastings, 2009). Several studies have demonstrated that impulsive 
sounds might affect the distribution and behavior of some fishes, 
potentially impacting foraging opportunities or increasing energetic 
costs (e.g., Fewtrell

[[Page 85716]]

and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992; 
Santulli et al., 1999; Paxton et al., 2017). However, some studies have 
shown no or slight reaction to impulse sounds (e.g., Pe[ntilde]a et 
al., 2013; Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott et 
al., 2012). More commonly, though, the impacts of noise on fishes are 
temporary.
    During the POA's MTRP, the effects of impact and vibratory 
installation of 30-in (76-cm) steel sheet piles at the POA on 133 caged 
juvenile coho salmon in Knik Arm were studied (Hart Crowser 
Incorporated et al., 2009; Houghton et al., 2010). Acute or delayed 
mortalities or behavioral abnormalities were not observed in any of the 
coho salmon. Furthermore, results indicated that the pile driving had 
no adverse effect on feeding ability or the ability of the fish to 
respond normally to threatening stimuli (Hart Crowser Incorporated et 
al., 2009; Houghton et al., 2010).
    SPLs of sufficient strength have been known to cause injury to 
fishes and fish mortality (summarized in Popper et al., 2014). However, 
in most fish species, hair cells in the ear continuously regenerate and 
loss of auditory function likely is restored when damaged cells are 
replaced with new cells. Halvorsen et al. (2012b) showed that a TTS of 
4 to 6 dB was recoverable within 24 hours for one species. Impacts 
would be most severe when the individual fish is close to the source 
and when the duration of exposure is long. Injury caused by barotrauma 
can range from slight to severe, can cause death, and is most likely 
for fish with swim bladders. Barotrauma injuries have been documented 
during controlled exposure to impact pile driving (Halvorsen et al., 
2012a; Casper et al., 2013, 2017).
    Fish populations in the proposed project area that serve as marine 
mammal prey could be temporarily affected by noise from pile 
installation and removal. The frequency range in which fishes generally 
perceive underwater sounds is 50 to 2,000 Hz, with peak sensitivities 
below 800 Hz (Popper and Hastings, 2009). Fish behavior or distribution 
may change, especially with strong and/or intermittent sounds that 
could harm fishes. High underwater SPLs have been documented to alter 
behavior, cause hearing loss, and injure or kill individual fish by 
causing serious internal injury (Hastings and Popper, 2005).
    Essential Fish Habitat (EFH) has been designated in the estuarine 
and marine waters in the vicinity of the proposed project area for all 
five species of salmon (i.e., chum salmon, pink salmon, coho salmon, 
sockeye salmon, and Chinook salmon; North Pacific Fishery Management 
Council (NPFMC), 2020, 2021), which are common prey of marine mammals, 
as well as for other species. (NPFMC, 2020). However, there are no 
designated habitat areas of particular concern in the vicinity of the 
Port, and therefore, adverse effects on EFH in this area are not 
expected.
    The greatest potential impact to fishes during construction would 
occur during impact pile installation. Impact piling would occur over 1 
to 3 hours on any given day across the construction season, with 
significant breaks between piles due to repositioning of the crane, 
installation and removal of temporary piles, and other construction 
sequencing. Additionally, impact driving of 72-in permanent piles would 
be mitigated with the use of a bubble curtain (see Proposed Mitigation 
section for full details) in all months of construction for piles 
driven in water greater than 3-m deep. Unattenuated impact driving in 
shallow water would be minimized as much as feasible by timing 
installation to occur during periods of low tide, when the pilings are 
out of water (``in the dry''). In-water construction activities would 
only occur during daylight hours, allowing fish to forage and transit 
the project area in the evening. Vibratory pile driving would possibly 
elicit behavioral reactions from fishes, such as temporary avoidance of 
the area, but is unlikely to cause injuries to fishes or have 
persistent effects on local fish populations. Construction also would 
have minimal permanent and temporary impacts on benthic invertebrate 
species, a marine mammal prey source. In addition, it should be noted 
that the area in question is low-quality habitat since it is already 
highly developed and experiences a high level of anthropogenic noise 
from normal operations and other vessel traffic at the POA. In general, 
any negative impacts on marine mammal prey species are expected to be 
minor and temporary.

In-Water Construction Effects on Potential Foraging Habitat

    The CTR project area is not considered to be high-quality habitat 
for marine mammals or marine mammal prey, such as fish, and it is 
anticipated that the long-term impact on marine mammals associated with 
CTR would be a small permanent decrease in low-quality potential 
habitat because of the expanded footprint of the new cargo terminals T1 
and T2. The CTR project is not expected to result in any habitat 
related effects that could cause significant negative consequences for 
individual marine mammals or their populations since installation and 
removal of in-water piles would be temporary and intermittent and the 
increased footprint of the facilities would destroy only a small amount 
of low-quality habitat, which currently experiences high levels of 
anthropogenic activity. Therefore, impacts of the project are not 
likely to have adverse effects on marine mammal foraging habitat in the 
proposed project area.

Estimated Take of Marine Mammals

    This section provides an estimate of the number of incidental takes 
proposed for authorization through promulgation of regulations and 
issuance of a LOA, which will inform NMFS' consideration of ``small 
numbers,'' the negligible impact determinations, and impacts on 
subsistence uses.
    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 use 
of the acoustic sources (i.e., vibratory and impact pile driving) has 
the potential to result in disruption of behavioral patterns for 
individual marine mammals. There is also some potential for auditory 
injury (Level A harassment) to result, primarily for high frequency 
cetaceans and phocids because predicted auditory injury zones are 
larger than for mid-frequency cetaceans and otariids. Auditory injury 
is unlikely to occur for mysticetes, mid-frequency cetaceans, and 
otariids due to measures described in the Proposed Mitigation section. 
The proposed mitigation and monitoring measures are expected to 
minimize the severity of the taking to the extent practicable. As 
described previously, no serious injury or mortality is anticipated or 
proposed to be authorized for this activity. Below, we describe how the 
proposed take numbers are estimated.
    For acoustic impacts, generally speaking, we estimate take by 
considering: (1) acoustic thresholds above which NMFS believes the best 
available science indicates marine mammals will be behaviorally 
harassed or incur some degree of permanent

[[Page 85717]]

hearing impairment; (2) the area or volume of water that will be 
ensonified above these levels in a day; (3) the density or occurrence 
of marine mammals within these ensonified areas; and, (4) the number of 
days of activities. We note that while these factors can contribute to 
a basic calculation to provide an initial prediction of potential 
takes, additional information that can qualitatively inform take 
estimates is also sometimes available (e.g., previous monitoring 
results or average group size). Below, we describe the factors 
considered here in more detail and present the proposed take estimates.

Acoustic Thresholds

    NMFS recommends the use of acoustic thresholds that identify the 
received level of underwater sound above which exposed marine mammals 
would be reasonably likely to be behaviorally harassed (equated to 
Level B harassment) or to incur PTS of some degree (equated to Level A 
harassment).
    Level B Harassment--Though significantly driven by received level, 
the onset of behavioral disturbance from anthropogenic noise exposure 
is also informed to varying degrees by other factors related to the 
source or exposure context (e.g., frequency, predictability, duty 
cycle, duration of the exposure, signal-to-noise ratio, distance to the 
source), the environment (e.g., bathymetry, other noises in the area, 
predators in the area), and the receiving animals (hearing, motivation, 
experience, demography, life stage, depth) and can be difficult to 
predict (e.g., Southall et al., 2007, 2021; Ellison et al., 2012). 
Based on the best scientific information available and the practical 
need to use a threshold based on a metric that is both predictable and 
measurable for most activities, NMFS typically uses a generalized 
acoustic threshold based on received level to estimate the onset of 
behavioral harassment. NMFS generally predicts that marine mammals are 
likely to be behaviorally harassed in a manner considered to be Level B 
harassment when exposed to underwater anthropogenic noise above root-
mean-squared pressure received levels (RMS SPL) of 120 dB re 1 [mu]Pa 
for continuous (e.g., vibratory pile driving, drilling) and above RMS 
SPL 160 dB re 1 [mu]Pa for non-explosive impulsive (e.g., seismic 
airguns) or intermittent (e.g., scientific sonar) sources. Generally 
speaking, Level B harassment estimates based on these behavioral 
harassment thresholds are expected to include any likely takes by TTS 
as, in most cases, the likelihood of TTS occurs at distances from the 
source less than those at which behavioral harassment is likely. TTS of 
a sufficient degree can manifest as behavioral harassment, as reduced 
hearing sensitivity and the potential reduced opportunities to detect 
important signals (conspecific communication, predators, prey) may 
result in changes in behavior patterns that would not otherwise occur.
    The POA's proposed activity includes the use of continuous 
(vibratory pile driving) and intermittent (impact pile driving) noise 
sources, and therefore, the RMS SPL thresholds of 120 and 160 dB re 1 
[mu]Pa are applicable.
    Level A harassment. NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0; 
NMFS, 2018) and the draft Updated Technical Guidance (NMFS, 2024) 
identify 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). This proposed rule estimates Level A 
harassment using the existing Technical Guidance (NMFS, 2018) as well 
as the draft Updated Technical Guidance (NMFS, 2024) because at the 
time of the final agency decision on this request for incidental take, 
it's possible NMFS may have made a final agency decision on the draft 
Guidance.
    These thresholds are provided in the tables below. The references, 
analysis, and methodology used in the development of the thresholds are 
described in NMFS' 2018 Technical Guidance and NMFS' 2024 draft Updated 
Technical Guidance, both of which may be accessed at: https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
    The POA's proposed activity includes the use of impulsive (impact 
pile driving) and non-impulsive (vibratory driving) sources.

             Table 7--NMFS' 2018 Thresholds Identifying the Onset of Permanent Threshold Shift (PTS)
----------------------------------------------------------------------------------------------------------------
                                                     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 NMFS' 2018 Technical Guidance. Hence, the
  subscript ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted
  within the generalized hearing range. The subscript associated with cumulative sound exposure level thresholds
  indicates the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW
  pinnipeds) and that the recommended accumulation period is 24 hours. The cumulative sound exposure level
  thresholds could be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle).
  When possible, it is valuable for action proponents to indicate the conditions under which these acoustic
  thresholds will be exceeded.


[[Page 85718]]


                Table 8--NMFS' 2024 Thresholds Identifying the Onset of Auditory Injury (AUD INJ)
----------------------------------------------------------------------------------------------------------------
                                                      AUD INJ acoustic thresholds * (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Underwater:
    Low-Frequency (LF) Cetaceans.......  Cell 1: Lp,0-pk,flat: 222   Cell 2: LE,p,LF,24h: 197 dB.
                                          dB; LE,p,LF,24h: 183 dB.
    High-Frequency (HF) Cetaceans......  Cell 3: Lp,0-pk,flat: 230   Cell 4: LE,p,HF,24h: 201 dB.
                                          dB; LE,p,HF,24h: 193 dB.
    Very High-Frequency (VHF) Cetaceans  Cell 5: Lp,0-pk,flat: 202   Cell 6: LE,p,VHF,24h: 181 dB.
                                          dB; LE,p,VHF,24h: 159 dB.
    Phocid Pinnipeds (PW) (Underwater).  Cell 7: Lp,0-pk.flat: 223   Cell 8: LE,p,PW,24h: 195 dB.
                                          dB; LE,p,PW,24h: 183 dB.
    Otariid Pinnipeds (OW) (Underwater)  Cell 9: Lp,0-pk,flat: 230   Cell 10: LE,p,OW,24h: 199 dB.
                                          dB; LE,p,OW,24h: 185 dB.
In-air:
    Phocid Pinnipeds (PA) (In-Air).....  Cell 11: Lp,0-pk.flat: 162  Cell 12: LE,p,PA,24h: 154 dB.
                                          dB; LE,p,PA,24h: 140 dB.
    Otariid Pinnipeds (OA) (In-Air)....  Cell 13: Lp,0-pk,flat: 177  Cell 14: LE,p,OA,24h: 177 dB.
                                          dB; LE,p,OA,24h: 163 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating AUD INJ 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 NMFS' 2018 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 are used in estimating the area ensonified above the 
acoustic thresholds, including source levels and transmission loss 
coefficient.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project (i.e., impact pile removal and 
vibratory pile installation and removal). Calculation of the area 
ensonified by the proposed action is dependent on the background sound 
levels at the project site, the source levels of the proposed 
activities, and the estimated transmission loss coefficients for the 
proposed activities at the site. These factors are addressed in order, 
below.
    Background Sound Levels at the Port of Alaska--As noted in the 
Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat section of this proposed rule, the POA is an industrial 
facility in a location with high levels of commercial vessel traffic, 
port operations (including dredging), and extreme tidal flow. Previous 
measurements of background noise at the POA have recorded a background 
SPL of 122.2 dB RMS (Austin et al., 2016). NMFS concurs that this SPL 
reasonably represents background noise near the proposed project area, 
and therefore, we have used 122.2 dB RMS as the threshold for Level B 
harassment (instead of 120 dB RMS).
    Sound Source Levels of Proposed Activities--The intensity of pile 
driving sounds is greatly influenced by factors such as the type of 
piles (material and diameter), hammer type, and the physical 
environment (e.g., sediment type) in which the activity takes place. In 
order to calculate the distances to the Level A harassment and the 
Level B harassment sound thresholds for the methods and piles being 
used in this project, we used acoustic monitoring data from sound 
source verification studies (both at the POA and elsewhere) to develop 
proxy source levels for the various pile types, sizes and methods 
(tables 9 and 10).
    The POA collected sound measurements during pile installation and 
removal for 3 seasons (Austin et al. 2016; Illingworth & Rodkin [I&R] 
2021a, 2021b); a summary of these data and findings can be found in 
appendix A of the POA's application.
    Vibratory Driving--NMFS concurs that the source levels proposed by 
the POA for vibratory installation and removal of all pile types are 
appropriate to use for calculating harassment isopleths for the POA's 
proposed CTR activities (tables 9 and 10). The proposed sound levels 
for vibratory removal are based on an analysis done for the POA's NES1 
IHA (89 FR 2832, January 14, 2024) and are partially based on sound 
source verification data measured at the POA during the PCT project 
(Illingworth and Rodkin, 2021a). Interestingly, the analyzed RMS SPL 
for the unattenuated vibratory removal of 24-in (61-cm) piles was much 
louder than the unattenuated vibratory removal of 36-in piles (91-cm), 
and even louder than the unattenuated vibratory installation of 24-in 
piles. Illingworth and Rodkin (2023) suggest that at least for data 
recorded at the POA, the higher 24-in (61-cm) removal levels are likely 
due to the piles being removed at rates of 1,600 to 1,700 revolutions 
per minute (rpm), while 36-in (91-cm) piles, which are significantly 
heavier than 24-in (61-cm) piles), were removed at a rate of 1,900 rpm. 
The slower rates combined with the lighter piles would cause the hammer 
to easily ``jerk'' or excite the 24-in (61-cm) piles as they were 
extracted, resulting in a louder rattling sound and louder sound 
levels. This did not occur for the 36-in (91-cm) piles, which were 
considerably heavier due to increased diameter, longer length, and 
greater thickness.
    The TPP found that for vibratory installation of 48-in piles, an 
air bubble curtain provided about a 9-dB reduction at 10 meters. An 8-
dB reduction at close-in positions was estimated for vibratory pile 
driving that occurred during the PCT project in 2021 (I&R 2021b). The 
PCT 2020 measurements indicated 2 to 8 dB reduction for the 48-in piles 
at 10 meters, but no apparent broadband reduction was found in the far-
field at about 2,800 meters (I&R 2021a). Far-field sound levels were 
characterized by very low frequency sound at or below 100 Hz, causing 
broadband measurements to remain above the ambient RMS level at 
approximately 2.8km from the source. However, levels at frequencies 
above 100 Hz were effectively reduced by the bubble curtain system. 
Because CIBW

[[Page 85719]]

are most sensitive to frequencies over 100 Hz, NMFS considers the use 
of bubble curtains during vibratory driving to be an effective and 
important mitigation measure for CIBW.
    Based on the aforementioned measurements conducted at POA, for 
vibratory driving during the CTR Project, it is assumed that a well-
designed and robust bubble curtain system will achieve a mean reduction 
of 7 dB at the source and will also reduce sound levels at frequencies 
over 100 Hz at longer ranges. The POA proposes to use a bubble curtain 
when water depth is greater than 3 meters during vibratory installation 
of all permanent (72-in) piles and during vibratory driving of 
temporary (24-in or 36-in) piles during the months of August through 
October when CIBWs are most likely to be present.
    Impact Driving--NMFS concurs that the source levels proposed by the 
POA for impact installation of all pile types are appropriate to use 
for calculating harassment isopleths for the POA's proposed CTR 
activities (tables 9 and 10). Impact driving of temporary piles (24-in 
and 36-in piles) is not currently proposed; however, in the unlikely 
event that vibratory driving is insufficient to stabilize a temporary 
pile, impact driving may be necessary. Sound source verification 
studies at the POA during the PCT project did not measure unattenuated 
impact driving of 24-in or 36-in piles; therefore, proxy sound levels 
from Navy (2015) are proposed.
    The TPP measured reductions of 9 to 12 dB for a 48-in pile 
installed with an impact hammer using a confined air bubble curtain. 
The PCT 2020 measurements (I&R 2021a) found reductions of about 10 dB 
when comparing the attenuated conditions that occurred with that 
project to unattenuated conditions for the TPP. The TPP did not report 
the reduction in sound levels in the acoustic far field; however, the 
computed distances to 125 dB RMS isopleths were essentially reduced by 
half with the bubble curtain (from 1,291 to 698 meters).
    It is currently unclear whether the POA's proposed bubble curtain 
system for the CTR project will be confined or unconfined; confined 
systems are typically more effective, especially in sites like Knik 
Arm, with high current velocity. Therefore, for impact pile 
installation for the CTR Project, it is assumed that a well-designed 
and robust bubble curtain system will achieve a mean reduction of 7 dB 
from the source. The POA proposes to use a bubble curtain system on all 
permanent piles in all months, which will be installed with both 
vibratory and impact hammers. The bubble curtain by necessity will be 
installed around each permanent pile as it is moved into position, and 
therefore, the bubble curtain will be available as a mitigation measure 
to reduce sound levels throughout each driving event for permanent 72-
in piles when water depth is greater than 3 meters. To account for 
piles driven in water less than 3m deep, NMFS has estimated 
approximately 0.5 unattenuated 72-in piles will be driven 
(approximately 43 minutes of impact driving and 5 minutes of vibratory 
driving) each month.
    Concurrent activities--The POA proposes to concurrently operate up 
to two hammers to install or extract piles at different parts of the 
project site, in order to reduce the need for pile driving during 
months of high beluga presence. When two noise sources have overlapping 
sound fields, the sources are considered additive and combined using 
the rules of dB addition. For addition of two simultaneous sources, the 
difference between the two sound source levels is calculated, and if 
that difference is between 0 and 1 dB, 3 dB are added to the higher 
sound source levels; if the difference is between 2 and 3 dB, 2 dB are 
added to the highest sound source levels; if the difference is between 
4 and 9 dB, 1 dB is added to the highest sound source levels; and with 
differences of 10 or more dB, there is no addition. For two 
simultaneous sources of different type (i.e., impact and vibratory 
driving), there is no sound source addition.
    Possible concurrent scenarios are shown in table 3; the predicted 
source values and transmission loss coefficients for these combinations 
are shown in table 11.
    Transmission Loss. For all piles driven with an active bubble 
curtain (``attenuated'' impact and vibratory driving), and for 
unattenuated impact installation, the POA proposed to use 15 as the TL 
coefficient, meaning they assume practical spreading loss (i.e., the 
POA assumes TL = 15*Log<INF>10</INF>(range)); NMFS concurs with this 
value and has assumed practical spreading loss for all (attenuated 
impact and vibratory) driving and unattenuated impact driving.
    The TL coefficient that the POA proposed for unattenuated vibratory 
installation and removal of piles is 16.5 (i.e., TL = 
16.5*Log<INF>10</INF>(range)). This value is an average of measurements 
obtained from two 48-in (122-cm) piles installed via an unattenuated 
vibratory hammer in 2016 (Austin et al., 2016). To assess the 
appropriateness of this TL coefficient to be used for the proposed 
project, NMFS examined and analyzed additional TL measurements recorded 
at the POA. This includes a TL coefficient of 22 (deep hydrophone 
measurement) from the 2004 unattenuated vibratory installation of one 
36-in (91-cm) pile at Port MacKenzie, across Knik Arm from the POA 
(Blackwell, 2004), as well as TL coefficients ranging from 10.3 to 18.2 
from the unattenuated vibratory removal of 24-in (61 cm) and 36-in (91-
cm) piles and the unattenuated vibratory installation of one 48-in 
(122-cm) pile at the POA in 2021 (I&R 2021, 2023). To account for 
statistical interdependence due to temporal correlations and equipment 
issues across projects, values were averaged first within each 
individual project, and then across projects. The mean and median value 
of the measured TL coefficients for unattenuated vibratory piles in 
Knik Arm by project are equal to 18.9 and 16.5, respectively. NMFS 
proposes to use the project median TL coefficient of 16.5 during 
unattenuated vibratory installation and removal of all piles during the 
CTR project. This value is representative of all unattenuated vibratory 
measurements in the Knik Arm, i.e., including data from POA and Port 
MacKenzie. Further, 16.5 is the mean of the 2016 measurements, which 
were made closer to the CTR proposed project area than other 
measurements and were composed of measurements from multiple directions 
(both north and south/southwest).
    In certain scenarios, the POA may perform concurrent vibratory 
driving of two piles. The POA proposed, and NMFS concurs, that in the 
event that both piles are unattenuated, the TL coefficient would be 
16.5; if both piles are attenuated, the TL coefficient would be 15. In 
the event that one pile is attenuated and one is unattenuated, the POA 
proposed a TL coefficient of 15.75 to be used in the acoustic modeling. 
NMFS evaluated the contributions of one attenuated and one unattenuated 
vibratory-driven pile to the sound field (assuming a 7-dB reduction in 
source level due to the bubble curtain for the attenuated source), and 
determined that the unattenuated source would likely dominate the 
received sound field. Therefore, the POA's proposed TL coefficient is 
conservative, and NMFS concurs with this value.

[[Page 85720]]



                                           Table 9--Summary of Unattenuated In-Water Pile Driving Proxy Levels
                                                                        [at 10 m]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Vibratory hammer
---------------------------------------------------------------------------------------------------------------------------------------------------------
              Method and pile type                                        dB rms                         TL coefficient   Data source for source levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel installation........................  161..................................................            16.5  U.S. Navy 2015.
24-in steel removal.............................  169..................................................                  NMFS average 2023; see 89 FR
                                                                                                                          2832.
36-in steel installation........................  166..................................................                  U.S. Navy 2015.
36-in steel removal.............................  159..................................................                  NMFS average 2023; see 89 FR
                                                                                                                          2832.
72-in steel.....................................  171..................................................                  I&R 2003, unpublished data for
                                                                                                                          Castrol Oil berthing dolphin
                                                                                                                          in Richmond, CA.
--------------------------------------------------------------------------------------------------------------------------------------------------------


 
                                                  Impact hammer
-----------------------------------------------------------------------------------------------------------------
                                                                                          Data source for source
                                           dB rms     dB SEL    dB peak   TL coefficient          levels
----------------------------------------------------------------------------------------------------------------
24-in steel............................        193        181        210            15.0  U.S. Navy 2015.
36-in steel............................        193        184        211                  U.S. Navy 2015.
72-in steel............................        203        191        217                  I&R model. Estimate
                                                                                           based on
                                                                                           interpolation of data
                                                                                           for piles 24 to 144
                                                                                           inches in diameter.
----------------------------------------------------------------------------------------------------------------


                                           Table 10--Summary of Attenuated In-Water Pile Driving Proxy Levels
                                                                        [at 10 m]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Vibratory hammer
---------------------------------------------------------------------------------------------------------------------------------------------------------
              Method and pile type                                        dB rms                         TL coefficient     Reference for proxy levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in steel installation........................  158.5................................................            15.0  I&R 2021a (measured).
24-in steel removal.............................  157..................................................                  I&R 2021a (measured).
36-in steel installation........................  160.5................................................                  I&R 2021a, 2021b (measured).
36-in steel removal.............................  154..................................................                  I&R 2021a (measured).
72-in steel.....................................  164..................................................                  Assumed 7-dB reduction
                                                                                                                          supported by I&R 2021a.
--------------------------------------------------------------------------------------------------------------------------------------------------------


 
                                                  Impact hammer
-----------------------------------------------------------------------------------------------------------------
                                                                                            Reference for proxy
                                           dB rms     dB SEL    dB peak   TL coefficient          levels
----------------------------------------------------------------------------------------------------------------
24-in steel............................        186        174        203            15.0  Assumed 7-dB reduction
                                                                                           supported by I&R
                                                                                           2021a.
36-in steel............................        186        177        204                  Assumed 7-dB reduction
                                                                                           supported by I&R
                                                                                           2021a.
72-in steel............................        196        184        210                  Assumed 7-dB reduction
                                                                                           supported by Caltrans
                                                                                           Compendium (2020).
----------------------------------------------------------------------------------------------------------------


[[Page 85721]]


                                                             Table 11--Source Values for Potential Concurrent Driving Scenarios \1\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                           Proxy source value
            Activity                        Method                  Pile type/size \2\           Attenuated or unattenuated     ---------------------------------------      TL      # Piles per
                                                                                                                                    dB RMS       dB SEL      dB peak    coefficient    day \3\
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Concurrent Driving (2 sources).  Vibratory/Vibratory.........  36-in and 36-in............  Attenuated/Attenuated..............        163.5  ...........  ...........           15            8
                                                                                            Attenuated/Unattenuated............          169  ...........  ...........        15.75            8
                                                                                            Unattenuated/Unattenuated..........          171  ...........  ...........         16.5            8
                                                               36-in and 72-in............  Attenuated/Attenuated..............          166  ...........  ...........           15            7
                                                                                            Unattenuated/Attenuated............          169  ...........  ...........        15.75            7
                                 Vibratory/Impact \1\........  36-in and 72-in............  Attenuated/Attenuated..............    160.5/196       --/184       --/210        15/15            8
                                                                                            Unattenuated/Attenuated............      166/196       --/184       --/210      16.5/15            7
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Concurrent vibratory and impact driving source values and TL coefficients are the same as for the piles driven individually (shown in tables 7 and 8), with no adjustments for concurrent
  driving. The Level A harassment isopleths would be determined by the calculated impact pile driving isopleths, and Level B harassment isopleth would be generated by vibratory pile driving.
\2\ POA may elect to use either 36-in or 24-in temporary piles; as 36-in piles are more likely and estimated to have larger ensonified areas, we have used these piles in our analyses of
  concurrent activities.
\3\ Piles per day were calculated as the maximum daily number of each type of pile (24-in and 36-in = 4 piles per hammer per day; 72-in piles = 3 piles per day) with complete overlap for 45
  minutes of driving with the largest possible combined source value, a scenario that would over-estimate duration of noise production given the estimated time required to drive 72-in piles
  with a vibratory hammer (10 minutes).


[[Page 85722]]

    Estimated Harassment Isopleths. All estimated Level B harassment 
isopleths are reported in tables 15 and 16. At POA, Level B harassment 
isopleths from the proposed project will be limited in some cases to 
less than the estimated value by the coastline along Knik Arm along and 
across from the project site. The maximum predicted isopleth distance 
for a single pile is 9,069 m during vibratory installation of 
unattenuated 72-in (182-cm) steel pipe piles. For concurrent driving 
the maximum isopleth distance is 9,363 m during vibratory driving of 
two unattenuated 24- or 36-in piles or during vibratory driving of one 
attenuated (24-, 36-, or 72-in) and one unattenuated (24- or 36-in) 
pile (tables 15 and 16).
    The ensonified area associated with Level A harassment is more 
technically challenging to predict due to the need to account for a 
duration component. Therefore, NMFS developed an optional User 
Spreadsheet tool to accompany the Technical Guidance that can be used 
to relatively simply predict an isopleth distance for use in 
conjunction with marine mammal density or occurrence to help predict 
potential takes. We note that because of some of the assumptions 
included in the methods underlying this optional tool, we anticipate 
that the resulting isopleth estimates are typically going to be 
overestimates of some degree, which may result in an overestimate of 
potential take by Level A harassment. However, this optional tool 
offers the best way to estimate isopleth distances when more 
sophisticated modeling methods are not available or practical. For 
stationary sources, such as pile driving, the optional User Spreadsheet 
tool predicts the distance at which, if a marine mammal remained at 
that distance for the duration of the activity, it would be expected to 
incur auditory injury. Inputs used in the optional User Spreadsheet 
tool and the resulting estimated isopleths are reported in tables 12 
through 14, below.

                                            Table 12--NMFS User Spreadsheet Inputs for 72-in Permanent Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                        Impact pile driving                                      Vibratory pile driving
                                    --------------------------------------------------------------------------------------------------------------------
                                              Attenuated                 Unattenuated \1\                Attenuated                Unattenuated \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet tab used...............                  (E.1) Impact pile driving
                                                    (A.1) Non-Impul, Stat, Cont.
                                    --------------------------------------------------------------------------------------------------------------------
Source Level.......................  184 dB SEL..................  191 dB SEL.................  164 dB RMS.................  171 dB RMS
Transmission Loss Coefficient......  15..........................  15.........................  15.........................  16.5
                                    --------------------------------------------------------------------------------------------------------------------
Weighting Factor Adjustment (kHz)..                              2
                                                                2.5
                                    --------------------------------------------------------------------------------------------------------------------
Time to install single pile                                      --
 (minutes).
                                                                 10
Number of strikes per pile.........                            5,743
                                                                 --
                                    --------------------------------------------------------------------------------------------------------------------
Piles per day......................  1--3........................  1..........................                              3
                                    --------------------------------------------------------------------------------------------------------------------
Distance of sound pressure level                                                              10
 measurement (m).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ To account for piles driven in water less than 3m deep, NMFS has estimated approximately 0.5 unattenuated 72-in piles will be driven (approximately
  43 minutes of impact driving and 5 minutes of vibratory driving) each month.


                                        Table 13--NMFS User Spreadsheet Inputs for Temporary (24- or 36-in) Piles
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Vibratory pile driving
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               24-in (61-cm) steel pipe                            36-in (91-cm) steel pipe
                                                 -------------------------------------------------------------------------------------------------------
                                                        Installation                 Removal                Installation                 Removal
                                                 -------------------------------------------------------------------------------------------------------
                                                     Atten.      Unatten.      Atten.      Unatten.      Atten.      Unatten.      Atten.      Unatten.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............................                                       (A.1) Non-Impul, Stat, Cont.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Level (dB RMS)...........................        158.5          161          157          169        160.5          166          154          159
Transmission Loss Coefficient...................           15         16.5           15         16.5           15         16.5           15         16.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Weighting Factor Adjustment (kHz)...............                                                    2.5
--------------------------------------------------------------------------------------------------------------------------------------------------------
Time to install or remove single pile (minutes).             30
                                                             45
                                                             30
                                                             45
--------------------------------------------------------------------------------------------------------------------------------------------------------
Number of strikes per pile......................                                                    --
--------------------------------------------------------------------------------------------------------------------------------------------------------
Piles per day...................................                                                     4
Distance of sound pressure level measurement (m)                                                    10
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                               24-in (61-cm) steel pipe
                                                               36-in (91-cm) steel pipe
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Attenuated
                                                        Unattenuated
                                                         Attenuated
                                                        Unattenuated
--------------------------------------------------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used............................                                         (E.1) Impact pile driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Level (dB RMS)...........................         174 dB SEL
                                                         181 dB SEL
                                                         177 dB SEL
                                                         184 dB SEL
--------------------------------------------------------------------------------------------------------------------------------------------------------
Transmission Loss Coefficient...................                                                    15
Weighting Factor Adjustment (kHz)...............                                                     2
Time to install or remove single pile (minutes).                                                    --

[[Page 85723]]

 
Number of strikes per pile......................                                                   1,000
Piles per day...................................                                                     1
Distance of sound pressure level measurement (m)                                                    10
--------------------------------------------------------------------------------------------------------------------------------------------------------


                     Table 14--NMFS User Spreadsheet Inputs for Concurrent Vibratory Driving
----------------------------------------------------------------------------------------------------------------
                                        24- or 36-in AND 24-in or 36-in               24- or 36-in AND 72-in
                               ---------------------------------------------------------------------------------
                                  Attenuated/     Attenuated/    Unattenuated/     Attenuated/    Unattenuated/
                                  attenuated     unattenuated     unattenuated     attenuated       attenuated
----------------------------------------------------------------------------------------------------------------
Spreadsheet Tab Used..........                            (A.1) Non-Impul, Stat, Cont.
                               ---------------------------------------------------------------------------------
Source Level (dB RMS).........           163.5             170              172             166              170
Transmission Loss Coefficient.              15           15.75             16.5              15            15.75
                               ---------------------------------------------------------------------------------
Weighting Factor Adjustment
 (kHz)........................                                         2.5
Time to install or remove a
 single pile (minutes)........                                         45
Number of strikes per pile....                                         --
                               ---------------------------------------------------------------------------------
Piles per day.................                         8
                                               7
                               ---------------------------------------------------------------------------------
Distance of sound pressure
 level measurement (m)........                                         10
----------------------------------------------------------------------------------------------------------------


 Table 15--Calculated Distance of Level A (based on NMFS' 2018 Technical Guidance) and Level B Harassment Isopleths by Pile Type and Pile Driving Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              Level A harassment distance (m)                 Level B
                                                                                  -------------------------------------------------------   harassment
            Activity                     Pile type/size           Attenuated or                                                            distance (m)
                                                                  unattenuated         LF         MF         HF         PW         OW       all hearing
                                                                                                                                            groups \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact..........................  24-in (61-cm)..............  Unattenuated......        735         27        876        394         29           1,585
                                                               Attenuated........        251          9        299        135         10             541
                                  36-in (91-cm)..............  Unattenuated......      1,165         42      1,387        624         46           1,585
                                                               Attenuated........        398         15        474        213         16             541
                                  72-in (182-cm).............  Unattenuated......     10,936        389     13,026      5,853        427           7,356
                                                               Attenuated (1 pile      3,734        133      4,448      1,999        146           2,512
                                                                per day).
                                                               Attenuated (2           5,928        211      7,061      3,173        231  ..............
                                                                piles per day).
                                                               Attenuated (3           7,767        277      9,252      4,157        303  ..............
                                                                piles per day).
Vibratory Installation..........  24-in (61-cm)..............  Unattenuated......         11          2         16          7          1           2,247
                                                               Attenuated........          8          1         11          5          1           2,630
                                  36-in (91-cm)..............  Unattenuated......         22          3         31         14          2           4,514
                                                               Attenuated........         11          1         15          7          1           3,575
                                  72-in (182-cm).............  Unattenuated......         19          3         27         12          2           9,069
                                                               Attenuated........          7          1         11          5          1           6,119
Vibratory Removal...............  24-in (61-cm)..............  Unattenuated......         42        4.6         60         27        2.4           6,861
                                                               Attenuated........         16        1.7         23         11          1           2,583
                                  36-in (91-cm)..............  Unattenuated......         11          2         15          7          1           1,699
                                                               Attenuated........          5          1          8          3          1           1,318
Concurrent Vibratory............  36-in AND 36-in............  Attenuated/                33        2.9         49         20        1.4           5,667
                                                                Attenuated.
                                                               Attenuated/                81        8.0        118         51        4.0           9,363
                                                                Unattenuated.
                                                               Unattenuated/              98         11        139         62        5.5           9,069
                                                                Unattenuated.
                                  36-in AND 72-in............  Attenuated/                45        3.9         66         27        1.9           8,318
                                                                Attenuated.
                                                               Unattenuated/              75        7.4        108         47        3.7           9,363
                                                                Attenuated.
Concurrent Vibratory/Impact.....  36-in AND 72-in............  Attenuated/             3,734        133      4,448      1,999        146           3,575
                                                                Attenuated (1
                                                                pile per day).
                                                               Attenuated/             5,928        211      7,061      3,173        231  ..............
                                                                Attenuated (2
                                                                piles per day).
                                                               Attenuated/             7,767        277      9,252      4,157        303  ..............
                                                                Attenuated (3
                                                                piles per day).
                                                               Unattenuated/           3,734        133      4,448      1,999        146           4,514
                                                                Attenuated (1
                                                                pile per day).
                                                               Unattenuated/           5,928        211      7,061      3,173        231  ..............
                                                                Unattenuated (2
                                                                piles per day).
                                                               Unattenuated/           7,767        277      9,252      4,157        303  ..............
                                                                Attenuated (3
                                                                piles per day).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Distances to thresholds are as modeled; however, interaction with shorelines would truncate zones. See figures 6-1 thorough 6-10 in the POA's
  application for further details.


[[Page 85724]]


Table 16--Calculated Distance and Areas of Level A (based on NMFS' Proposed 2024 Update to the 2018 Technical Guidance) and Level B Harassment Isopleths
                                                          by Pile Type and Pile Driving Method
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                              Level A harassment distance (m)                 Level B
                                                                                  -------------------------------------------------------   harassment
            Activity                     Pile type/size           Attenuated or                                                            distance (m)
                                                                  unattenuated         LF         HF        VHF         PW         OW       all hearing
                                                                                                                                            groups \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact..........................  24-in (61-cm)..............  Unattenuated......        732         94      1,133        651        243           1,585
                                                               Attenuated........        250         32        387        222         83             541
                                  36-in (91-cm)..............  Unattenuated......      1,160        148      1,796      1,031        385           1,585
                                                               Attenuated........        397         51        613        352        132             541
                                  72-in (182-cm).............  Unattenuated......     10,896      1,390     16,861      9,679      3,608           7,356
                                                               Attenuated (1 pile      3,720      474.7      5,757      3,305      1,232           2,512
                                                                per day).
                                                               Attenuated (2           5,906      753.5      9,139      5,246      1,956
                                                                piles per day).
                                                               Attenuated (3           7,739      987.4     11,976      6,875      2,563
                                                                piles per day).
Vibratory Installation..........  24-in (61-cm)..............  Unattenuated......       14.1        5.9       11.8       17.8        6.6           2,247
                                                               Attenuated........         10        3.8        8.1       12.8        4.3           2,630
                                  36-in (91-cm)..............  Unattenuated......       28.4       11.9       23.6       35.7       13.3           4,514
                                                               Attenuated........       13.6        5.2       11.1       17.5        5.9           3,575
                                  72-in (182-cm).............  Unattenuated......       24.6       10.3       20.5         31       11.5           9,069
                                                               Attenuated........        9.2        3.5        7.5       11.9          4           6,119
Vibratory Removal...............  24-in (61-cm)..............  Unattenuated......       55.2       23.1       45.9       69.5       25.8           6,861
                                                               Attenuated........       10.4          4        8.5       13.4        4.5           2,583
                                  36-in (91-cm)..............  Unattenuated......       13.7        5.7       11.4       17.2        6.4           1,699
                                                               Attenuated........        6.6        2.5        5.4        8.4        2.8           1,318
Concurrent Vibratory/Vibratory..  36-in AND 36-in............  Attenuated/              44.7       17.2       36.5       57.5       19.4           5,667
                                                                Attenuated.
                                                               Attenuated/             107.6       43.3       88.8      136.9       48.5           9,363
                                                                Unattenuated.
                                                               Unattenuated/           127.7       53.5      106.3      160.7       59.7           9,069
                                                                Unattenuated.
                                  36-in AND 72-in............  Attenuated/                60       23.1         49       77.3         26           8,318
                                                                Attenuated.
                                                               Unattenuated/            98.9       39.8       81.6      125.8       44.6           9,363
                                                                Attenuated.
Concurrent Vibratory/Impact.....                               Attenuated/             3,720      474.7      5,757      3,305      1,232           3,575
                                                                Attenuated (1
                                                                pile per day).
                                                               Attenuated/             5,906      753.5      9,139      5,246      1,956
                                                                Attenuated (2
                                                                piles per day).
                                                               Attenuated/             7,739      987.4     11,976      6,875      2,563
                                                                Attenuated (3
                                                                piles per day).
                                  36-in AND 72-in............  Unattenuated/           3,720      474.7      5,757      3,305      1,232           4,514
                                                                Attenuated (1
                                                                pile per day).
                                                               Unattenuated/           5,906      753.5      9,139      5,246      1,956
                                                                Attenuated (2
                                                                piles per day).
                                                               Unattenuated/           7,739      987.4     11,976      6,875      2,563
                                                                Attenuated (3
                                                                piles per day).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Distances to thresholds are as modeled; however, interaction with shorelines would truncate zones. See figures 6-1 thorough 6-10 in the POA's
  application for further details.

Marine Mammal Occurrence

    In this section, we provide information about the occurrence of 
marine mammals, including density or other relevant information, which 
will inform the take calculations. Available information regarding 
marine mammal occurrence and abundance in the vicinity of the POA 
includes monitoring data from the PCT and SFD projects. These programs 
produced a unique and comprehensive data set of marine mammal sightings 
and for CIBWs, locations and movements near the POA (61N Environmental, 
2021, 2022a, 2022b; Easley-Appleyard and Leonard, 2022). This is the 
most current data set available for Knik Arm. During the PCT and SFD 
projects, the POA's marine mammal monitoring programs included 11 PSOs 
working from four elevated, specially designed monitoring stations 
located along a 9-km stretch of coastline surrounding the POA. The 
number of days data was collected varied among years and projects, with 
128 days during PCT Phase 1 in 2020, 74 days during PCT Phase 2 in 
2021, and 13 days during SFD in 2022 (see table 6-15 in the POA's 
application for additional information regarding CIBW monitoring data). 
PSOs during these projects used 25-power ``big-eye'' and hand-held 
binoculars to detect and identify marine mammals and theodolites to 
track movements of CIBW groups over time and collect location data 
while they remained in view.
    These POA monitoring programs were supplemented in 2021 with a 
NMFS-funded visual marine mammal monitoring project that collected data 
during non-pile driving days during PCT Phase 2 (Easley-Appleyard and 
Leonard, 2022). NMFS replicated the POA monitoring efforts, as 
feasible, including use of 2 of the POA's monitoring platforms, 
equipment (Big Eye binoculars, theodolite, 7x50 reticle binoculars), 
data collection software, monitoring and data collection protocol, and 
observers; however, the NMFS-funded program utilized only 4 PSOs and 2 
observation stations along with shorter (4- to 8-hour) observation 
periods compared to PCT or SFD data collection, which included 11 PSOs, 
4 observation stations, and most observation days lasting close to 10 
hours. Despite the differences in effort, the NMFS dataset fills in 
gaps during the 2021 season and is thus valuable in this analysis. 
NMFS' PSOs monitored for 231.6 hours on 47 non-consecutive days in 
July, August, September, and October.
    Density data are not available for any of the relevant species in 
this area; therefore, we have used reasonable yearly, monthly, or 
hourly occurrence estimates based on the previous POA monitoring 
datasets for all species. Table 17 shows the estimated occurrence rates 
for non-CIBW species at the POA; descriptions are provided in the text 
below.

[[Page 85725]]



                         Table 17--Estimated Occurrence for Non-CIBW Species at the POA
----------------------------------------------------------------------------------------------------------------
                                                                                     Estimated     Estimated 5-
              Species                     Timeframe         Estimated occurrence      annual           year
                                                                   rates            occurrence      occurrence
----------------------------------------------------------------------------------------------------------------
Gray whale........................  Yearly...............  6/year...............               6              30
Humpback whale....................                         4/year...............               4              20
Killer whale......................                         6/year...............               6              30
Steller sea lion..................                         9/year...............               9              45
Harbor porpoise...................  Hourly...............  0.15/hour............           1,314           6,570
Harbor seal.......................                         1/hour...............           8,760          43,800
----------------------------------------------------------------------------------------------------------------

Gray Whale

    Sightings of gray whales in the proposed project area are rare. 
Few, if any, gray whales are expected to approach the proposed project 
area. However, based on three separate sightings of single gray whales 
near the POA in 2020 and 2021 (61N Environmental, 2021, 2022a; Easley-
Appleyard and Leonard, 2022), the POA anticipates that up to six 
individuals could occur within estimated harassment zones each year 
during CTR project activities.

Humpback Whale

    Sightings of humpback whales in the proposed project area are rare, 
and few, if any, humpback whales are expected to approach the proposed 
project area. However, there have been a few observations of humpback 
whales near the POA. Based on the two sightings in 2017 of what was 
likely a single individual at the Anchorage Public Boat Dock at Ship 
Creek (ABR, Inc., 2017) south of the Project area, the POA requested 
authorization of six takes of humpback whales per year of the CTR 
project. However, given the maximum number of humpback whales observed 
within a single construction season was two (in 2017), NMFS instead 
anticipates that only up to four humpback whales could be exposed to 
project-related underwater noise per year during the CTR project.

Killer Whale

    Few, if any, killer whales are expected to approach the CTR project 
area. No killer whales were sighted during previous monitoring programs 
for POA construction projects, including the 2016 TPP, 2020 PCT, and 
2022 SFD projects (Prevel-Ramos et al., 2006; Markowitz and McGuire, 
2007; Cornick and Saxon-Kendall, 2008, 2009; Cornick et al., 2010, 
2011; ICRC, 2009, 2010, 2011, 2012; Cornick and Pinney, 2011; Cornick 
and Seagars, 2016; 61N Environmental, 2021, 2022b), except during PCT 
construction in 2021, when two killer whales were sighted (61N 
Environmental, 2022a). Previous sightings of transient killer whales 
have documented pod sizes in upper Cook Inlet between one and six 
individuals (Shelden et al., 2003). While unlikely, it is possible that 
killer whales could approach the POA from the northern portion of Knik 
Arm, and immediately enter into a Level A harassment zone before PSOs 
are able to shut down pile driving activities. The POA estimates, and 
NMFS concurs, that one pod (assumed to be six individuals) could be 
taken by Level A harassment over the 5 years of the CTR project. NMFS 
also concurs that no more than one pod (assumed to be six individuals) 
could occur within the Level B harassment zones during CTR project 
activities per year.

Harbor Porpoise

    Monitoring data recorded from 2005 through 2022 were used to 
evaluate hourly sighting rates for harbor porpoises in the proposed CTR 
area (see table 4-3 in the POA's application). During most years of 
monitoring, no harbor porpoises were observed. However, there has been 
an increase in harbor porpoise sightings in upper Cook Inlet in recent 
decades (e.g., 61N Environmental, 2021, 2022a; Shelden et al., 2014). 
The highest sighting rate for any recorded year during in-water pile 
installation and removal was an average of 0.037 harbor porpoises per 
hour during PCT construction in 2021, when observations occurred across 
most months. Given the uncertainty around harbor porpoise occurrence at 
the POA and potential that occurrence is increasing, the POA calculated 
requested takes using a sighting rate of 0.5 harbor porpoises per hour. 
For the recent NES1 project (88 FR 76576, November 6, 2023), NMFS 
estimated that a more realistic sighting rate would be closer to 
approximately 0.07 harbor porpoises per hour (the 2021 rate of 0.037 
harbor porpoises per hour doubled). However, the sizes of the 
ensonified areas for the NES1 project are much smaller than those 
predicted for the proposed CTR project. Based on the larger ensonified 
areas, which more closely resemble the observable area from the PCT 
project, the cryptic nature of the species, and the potential for 
increased occurrence of harbor porpoise in and around upper Cook Inlet, 
NMFS estimates that approximately 0.15 harbor porpoises per hour (four 
times the maximum observed 2021 rate of 0.037 per hour) may be observed 
near the proposed CTR area during the 5 years covered under this 
proposed rulemaking.

Steller Sea Lion

    Steller sea lions are anticipated to occur in low numbers within 
the proposed CTR project area as summarized in the Description of 
Marine Mammals in the Area of Specified Activities section. Similar to 
the approach used above for harbor porpoises, the POA used previously 
recorded sighting rates of Steller sea lions near the POA to estimate 
requested take for this species. During SFD construction in May and 
June of 2022, the hourly sighting rate for Steller sea lions was 0.028. 
The hourly sighting rate for Steller sea lions in 2021, the most recent 
year with observations across most months, was approximately 0.01. The 
highest number of Steller sea lions that have been observed during the 
2020-2022 monitoring efforts at the POA was nine individuals (eight 
during PCT Phase 1 monitoring and one during NMFS' 2021 monitoring).
    Recent counts of sightings of Steller sea lions around the POA may 
include multiple re-sights of single individuals. For instance, in 
2016, Steller sea lions were observed on 2 separate days. On May 2, 
2016, one individual was sighted, while 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 (Cornick 
and Seagars, 2016). Given the proximity in time and space, it is 
believed these five sightings were of the same individual sea lion. The 
POA is concerned that multiple re-sights of a single individual within 
a day may overestimate the true number of individuals exposed to sound

[[Page 85726]]

levels at or above harassment thresholds over the course of the 
proposed project. Therefore, given the uncertainty around Steller sea 
lion occurrence at the POA and potential that occurrence is increasing, 
the POA estimated that approximately 0.14 Steller sea lions per hour 
(the May and June 2022 rate of 0.028 Steller sea lions per hour 
multiplied by a factor of 5) may be observed near the proposed CTR 
project areas per hour of hammer use. However, the highest number of 
Steller sea lion sightings during the 2020-2022 monitoring efforts at 
the POA was nine (eight during PCT Phase 1 monitoring and one during 
NMFS' 2021 monitoring).
    Given the POA's estimate assumes a higher Steller sea lion sighting 
rate (0.14) than has been observed at the POA and results in an 
estimate that is more than double the maximum number of Steller sea 
lions observed in a year, NMFS believes that the sighting rate proposed 
by the POA overestimates potential exposures of this species. Based on 
the ensonified areas, which closely resemble the observable area from 
the PCT project, the potential for re-sightings of individual animals, 
and the uncertainty around increased occurrence of Steller sea lions in 
and around upper Cook Inlet, NMFS instead proposes that nine Steller 
sea lions (the maximum number observed in a single year between 2020 
and 2022 during projects with similar sized harassment isopleths) may 
be taken each year during the 5 years covered under this proposed 
rulemaking, up to a total of 45 individuals over the course of the 
project.

Harbor Seal

    No known harbor seal haulout or pupping sites occur in the vicinity 
of the POA. In addition, harbor seals are not known to reside in the 
proposed CTR project area, but they are seen regularly near the 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 CTR project area. Harbor seals often appear curious 
about onshore activities and may approach closely. The mouth of Ship 
Creek, where harbor seals linger, is about 1,500 m from the southern 
end of the CTR.
    The POA evaluated marine mammal monitoring data to calculate hourly 
sighting rates for harbor seals in the CTR project area (see table 4-1 
in the POA's application). Of the 524 harbor seal sightings in 2020 and 
2021, 93.7 percent of the sightings were of single individuals; only 
5.7 percent of sightings were of two individual harbor seals, and only 
0.6 percent of sightings reported three harbor seals. Sighting rates of 
harbor seals were highly variable and appeared to have increased during 
monitoring between 2005 and 2022. It is unknown whether any potential 
increase was due to local population increases or habituation to 
ongoing construction activities. The highest individual hourly sighting 
rate recorded for a previous year was used to quantify take of harbor 
seals for in-water pile installation and removal associated with CTR. 
This occurred in 2021 during PCT Phase 2 construction, when harbor 
seals were observed from May through September. A total of 220 harbor 
seal sightings were observed over 734.9 hours of monitoring, at an 
average rate of 0.30 harbor seal sightings per hour. The maximum 
monthly sighting rate occurred in September 2020 and was 0.51 harbor 
seal sightings per hour. Based on these data, the POA estimated, and 
NMFS concurs, that approximately one harbor seal (the maximum monthly 
sighting rate (0.51) rounded up) may be observed near the CTR project 
per hour of hammer use.

Beluga Whale

    CIBWs are regular and frequent visitors to Knik Arm, sometimes 
passing by the POA multiple times a day, as documented by the previous 
PAMP monitoring projects (61N Environmental, 2021, 2022a, 2022b). 
Distances from CIBW sightings to the CTR project site from the POA and 
NMFS-funded monitoring programs ranged from less than 10 m up to nearly 
15 km. The robust marine mammal monitoring programs in place at the POA 
from 2020 through 2022 located, identified, and tracked CIBWs at 
greater distances from the proposed project site than previous 
monitoring programs (i.e., Kendall and Cornick, 2015) and has 
contributed to a better understanding of CIBW movements in upper Cook 
Inlet (e.g., Easley-Appleyard and Leonard, 2022).
    For the NES1 project, NMFS and the POA collaboratively developed a 
new sighting rate methodology that incorporates a spatial component for 
CIBW observations, which allows for more accurate estimation of 
potential take of CIBWs (89 FR 2832, January 14, 2024). We have used 
this same methodology in the analysis of estimated CIBW incidental take 
during the CTR project. A detailed description of the differences from 
the sighting-rate methods used in the PCT and SFD projects can be found 
in the notice of proposed IHA for the NES1 project (88 FR 76576, 
November 6, 2023).
    During the POA's and NMFS' marine mammal monitoring programs for 
the PCT and SFD projects (table 18), PSOs had an increased ability to 
detect, identify, and track CIBWs groups at greater distances from the 
project work site when compared with previous years because of the 
POA's expanded monitoring program as described above. This meant that 
observations of CIBWs in the 2020-2022 dataset (table 18) include 
sightings of individuals at distances far outside some of the 
ensonified areas estimated for the CTR project and at ranges close to 
the extent of the larger ensonified areas (tables 15 and 16). 
Therefore, it would not be appropriate to group all CIBW observations 
from these datasets into a single sighting rate as was done for the PCT 
and SFD projects. Rather, we propose that CIBW observations should be 
considered in relation to their distance to the CTR project site when 
determining appropriate sighting rates to use when estimating take for 
this project. This would help to ensure that the sighting rates used to 
estimate take are representative of CIBW presence in the proposed 
ensonified areas.

                Table 18--Marine Mammal Monitoring Data Used for CIBW Sighting Rate Calculations
----------------------------------------------------------------------------------------------------------------
                                      Monitoring type and data    Number of CIBW  Number of CIBW     Number of
               Year                            source               group fixes       groups           CIBWs
----------------------------------------------------------------------------------------------------------------
2020.............................  PCT: POA Construction                   2,653             245             987
                                    Monitoring 61N
                                    Environmental, 2021.
2021.............................  PCT: NMFS Monitoring Easley-              694         \1\ 109             575
                                    Appleyard and Leonard, 2022.
2021.............................  PCT: POA Construction                   1,339             132             517
                                    Monitoring 61N
                                    Environmental, 2021, 2022a.
2022.............................  SFD: POA Construction                     151               9              41
                                    Monitoring 61N
                                    Environmental, 2022b.
----------------------------------------------------------------------------------------------------------------
\1\ This number differs slightly from Table 6-8 in the POA's application due to our removal of a few duplicate
  data points in the NMFS data set.


[[Page 85727]]

    To incorporate a spatial component into the sighting rate 
methodology, the POA calculated each CIBW group's closest point of 
approach (CPOA) relative to the CTR proposed project site. The 2020-
2022 marine mammal monitoring programs (table 18) enabled the 
collection, in many cases, of multiple locations of CIBW groups as they 
transited through Knik Arm, which allowed for track lines to be 
interpolated for many groups. The POA used these track lines, or single 
recorded locations in instances where only one sighting location was 
available, to calculate each group's CPOA. CPOAs were calculated in 
ArcGIS software using the Geographic Positioning System (GPS) 
coordinates provided for documented sightings of each group (for 
details on data collection methods, see 61N Environmental, 2021, 2022a, 
2022b; Easley-Appleyard and Leonard, 2022) and the CTR location 
midpoint, centered on the proposed project site. A CIBW group was 
defined as a sighting of one or more CIBWs as determined during data 
collection. The most distant CPOA location to CTR was 11,138 m and the 
closest CPOA location was 6 m.
    The cumulative density distribution of CPOA values represents the 
percentage of CIBW observations that were within various distances to 
the CTR action site (figure 4). This distribution shows how CIBW 
observations differed with distances to the CTR site and was used to 
infer appropriate distances within which to estimate spatially-derived 
CIBW sighting rates (figure 4). The POA implemented a piecewise 
regression model that detected breakpoints (i.e., points within the 
CPOA data at which statistical properties of the sequence of 
observational distances changed) in the cumulative density distribution 
of the CPOA locations, which they proposed to represent spatially-based 
sighting rate bins for use in calculating CIBW sighting rates. The POA 
used the ``Segmented'' package (Muggeo, 2020) in the R Statistical 
Software Package (R Core Team, 2022) to determine statistically 
significant breakpoints in the linear distances of the CIBW data using 
this regression method (see section 6.5.5.3 of the POA's application 
for more details regarding this statistical analysis). This analysis 
identified breakpoints in the CPOA locations at 195.7, 2,337.0, 
3,154.7, and 6,973.9 m (figure 4).
[GRAPHIC] [TIFF OMITTED] TP28OC24.005

    Piecewise regression is a common tool for modeling ecological 
thresholds (Lopez et al., 2020; Whitehead et al., 2016; Atwood et al., 
2016). In a similar scenario to the one outlined above, Mayette et al. 
(2022) used piecewise regression methods to model the distances between 
two individual CIBWs in a group in a nearshore and a far shore 
environment. For the POA's analysis, the breakpoints (i.e., 195.7, 
2,337.0, 3,154.7, and 6,973.9 m) detect a change in the frequency of 
CIBW groups sighted and the slope of the line between two points 
indicates the magnitude of change. A greater positive slope indicates a 
greater accumulation of sightings over the linear distance (x-axis) 
between the defining breakpoints, whereas a more level slope (i.e., 
closer to zero) indicates a lower accumulation of sightings over that 
linear distance (x-axis) between those defining breakpoints (figure 4; 
see table 6-16 in the POA's application for the slope estimates for the 
empirical cumulative distribution function).
    The breakpoints identified by the piecewise regression analysis are 
in agreement with what is known about CIBW behavior in Knik Arm based 
on recent monitoring efforts (61N Environmental, 2021, 2022a, 2022b;

[[Page 85728]]

Easley-Appleyard and Leonard, 2022). Observation location data 
collected during POA monitoring programs indicate that CIBWs were 
consistently found in higher numbers in the nearshore areas, along both 
shorelines, and were found in lower numbers in the center of the Arm. 
Tracklines of CIBW group movements collected from 2020 to 2022 show 
that CIBWs displayed a variety of movement patterns that included 
swimming close to shore past the POA on the east side of Knik Arm 
(defined by breakpoint 1 at 195.7 m), with fewer CIBWs swimming in the 
center of Knik Arm (breakpoints 1 to 2, at 195.7 to 2,337 m). CIBWs 
commonly swam past the POA close to shore on the west side of Knik Arm, 
with no CIBWs able to swim farther from the POA in that area than the 
far shore (breakpoints 2 to 3, at 2,337 to 3,154.7 m). Behaviors and 
locations beyond breakpoint 4 (6,973.9 m) include swimming past the 
mouth of Knik Arm between the Susitna River area and Turnagain Arm; 
milling at the mouth of Knik Arm but not entering the Arm; and milling 
to the northwest of the POA without exiting Knik Arm. The shallowness 
of slope 5, at distances greater than 6,973.9 m, could be due to 
detection falloff from a proximity (distance) bias, which would occur 
when PSOs are less likely to detect CIBW groups that are farther away 
than groups that are closer.
    The POA, in collaboration with NMFS, used the distances detected by 
the breakpoint analysis to define five sighting rate distance bins for 
CIBWs in the NES1 project area. Each breakpoint (196, 2,337, 3,155, and 
6,974 m, and the complete data set of observations [>6,974 m]) was 
rounded up to the nearest meter and considered the outermost limit of 
each sighting rate bin, resulting in five identified bins (table 19). 
All CIBW observations less than each bin's breakpoint distance were 
used to calculated that bin's respective monthly sighting rates (e.g., 
all sightings from 0 to 196 m are included in the sighting rates 
calculated for bin number 1, all sightings from 0 to 2,337 m are 
included in the sighting rates calculated for bin number 2, and so on). 
CTR construction is anticipated to take place in the months of April 
through November over the 5-year timeframe of the proposed rulemaking; 
therefore, monthly sighting rates were only derived for these months 
(table 19).

                                      Table 19--CIBW Monthly Sighting Rates for Different Spatially-Based Bin Sizes
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                    CIBW/Hour \1\
                   Bin number                     Distance ---------------------------------------------------------------------------------------------
                                                    (m)       April       May        June       July      August    September     October      November
--------------------------------------------------------------------------------------------------------------------------------------------------------
1..............................................        196       0.05       0.06       0.10       0.04       0.82         0.59         0.51         0.10
2..............................................      2,338       0.34       0.16       0.15       0.09       1.55         1.42         1.09         0.65
3..............................................      3,155       0.36       0.22       0.21       0.09       2.02         1.89         1.98         0.72
4..............................................      6,974       0.67       0.33       0.29       0.13       2.24         2.18         2.42         0.73
5..............................................     >6,974       0.71       0.39       0.30       0.13       2.29         2.23         2.56         0.73
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Observation hours have been totaled from the PCT 2020 and 2021 programs, the NMFS 2021 data collection effort, and the SFD 2022 program (61N
  Environmental 2021, 2022a, 2022b; Easley-Appleyard and Leonard, 2022).

Take Estimation

    In this section, we describe how the information provided above is 
synthesized to produce a quantitative estimate of the take that is 
reasonably likely to occur and proposed for authorization.
    To quantitatively assess exposure of marine mammals to noise from 
pile driving activities, we used the occurrence estimate (number/unit 
of time; tables 17 and 19) and the estimated work hours per year (table 
20) to determine the number of animals potentially exposed to an 
activity. Because the size of the Level A harassment zones may exceed 
the shutdown zones (see the Proposed Mitigation section) and the limits 
of PSO visibility during impact driving activities, the number of takes 
by Level A harassment was estimated based on the proportion of work 
hours allocated to impact pile driving (table 20) for all species 
except killer whales, which have smaller predicted Level A harassment 
zones, and CIBWs, which have larger proposed shutdown zones, described 
in further detail below.

   Table 20--Estimated Predicted Number of Hours of Impact and Vibratory Hammer Use for Each Construction Year
----------------------------------------------------------------------------------------------------------------
                                                                                                   Proportion of
                      Year                            Impact         Vibratory    Total duration   impact hammer
                                                  duration (hrs)  duration (hrs)       (hrs)            use
----------------------------------------------------------------------------------------------------------------
1...............................................           98.90           55.00          153.90            0.64
2...............................................           87.43           47.92          135.35            0.65
3...............................................           38.70           96.50          135.20            0.29
4...............................................           87.43           50.42          137.85            0.63
5...............................................           81.70           55.50          137.20            0.60
----------------------------------------------------------------------------------------------------------------

    The equation used to calculate estimated take by Level A harassment 
for species with yearly occurrence estimates is:

Level A harassment estimate = occurrence x proportion of impact hammer 
use

where occurrence per year is taken from table 17, and proportion of 
impact hammer use per year from table 20. For species with hourly 
occurrence estimates, the equation is:

Level A harassment estimate = (hourly occurrence x total duration in 
hours) x proportion of impact hammer use

    Estimates of take by Level A and Level B harassment for all species 
are based on the best available data. NMFS proposes to authorize total 
takes for each species by Level A and Level B harassment over the 5-
year period of the proposed ITR as calculated and shown in the relevant 
tables, with annual take by Level A and Level B harassment for

[[Page 85729]]

each species not to exceed the maximum annual values shown in tables 
21, 22, and 24.

  Table 21--Estimated Take by Level A Harassment in Each of the 5 Years and in Total for Non-CIBW Marine Mammal
                                  Species in the Proposed CTR Project Area \1\
----------------------------------------------------------------------------------------------------------------
                                                        Potential level A harassment by year
              Species              -----------------------------------------------------------------------------
                                         1            2            3            4            5          Total
----------------------------------------------------------------------------------------------------------------
Gray whale........................            4            4            2            4            4           18
Humpback whale....................            3            3            1            3            2           12
                                   -----------------------------------------------------------------
Killer whale......................                                 6                                           6
                                   -----------------------------------------------------------------
Harbor porpoise...................           15           13            6           13           12           59
Steller sea lion..................            6            6            3            6            5           26
Harbor seal.......................           98           88           39           87           82          394
----------------------------------------------------------------------------------------------------------------
\1\ Annual take may not be distributed exactly as shown; NMFS proposes to authorize total take over the 5 year
  construction period, with annual take by Level A harassment for each species not to exceed the maximum annual
  value shown in years 1-5.

    Proposed estimates of take by Level B harassment for non-CIBW 
species were calculated as the difference between the estimated Level A 
harassment exposures and total estimated yearly occurrence (either the 
estimated yearly occurrence from table 17 or calculated as the hourly 
occurrence from table 17 multiplied by the total yearly duration in 
table 20) for each stock.

  Table 22--Estimated Take by Level B Harassment in Each of the 5 Years and in Total for Non-CIBW Marine Mammal
                                  Species in the Proposed CTR Project Area \1\
----------------------------------------------------------------------------------------------------------------
                                                        Potential level B harassment by year
               Stock               -----------------------------------------------------------------------------
                                         1            2            3            4            5          Total
----------------------------------------------------------------------------------------------------------------
Gray whale........................            2            2            4            2            2           12
Humpback whale....................            1            1            3            1            2            8
Killer whale......................            6            6            6            6            6           30
Harbor porpoise...................            8            7           14            8            8           45
Steller sea lion..................            3            3            6            3            4           20
Harbor seal.......................           55           47           96           51           55          304
----------------------------------------------------------------------------------------------------------------
\1\ Annual take may not be distributed exactly as shown; NMFS proposes to authorize total take over the 5 year
  construction period, not to exceed the sum of the maximum annual values shown in years 1-5 in Tables 21 and
  22.

Beluga Whale

    Potential exposures above harassment thresholds of CIBWs, which we 
equate with takes, were calculated by multiplying the total number of 
vibratory installation or removal hours per month for each sized/shaped 
pile based on the anticipated construction schedule (table 2) with the 
corresponding sighting rate month and sighting rate distance bin (table 
19). For example, the Level B harassment isopleth distance for the 
vibratory installation of 36-in (91-cm) piles is 4,514 m, which falls 
within bin number 4 (table 19). Therefore, take for this activity is 
calculated by multiplying the total number of hours estimated each 
month to install 36-in piles via a vibratory hammer by the monthly CIBW 
sighting rates calculated for bin number 4 (table 19). The resulting 
estimated CIBW exposures were totaled for all activities in each month 
(table 23).
    In their calculation of CIBW take, the POA assumed that only 36-in 
template piles would be installed (rather than 24-in) and removed 
during the project. If 24-in piles are used for temporary stability 
template piles, it would be assumed that the potential impacts of this 
alternate construction scenario and method on marine mammals are 
fungible (i.e., that potential impacts of installation and removal of 
24-in steel pipe piles would be similar to the potential impacts of 
installation and removal of 36-in steel pipe piles). While removal of 
24-in piles may be louder than removal of 36-in piles (tables 9 and 
10), installation would be significantly quieter. Given the number of 
piles to be installed and extracted using vibratory methods, overall 
impacts from 36-in piles are expected to be greater than those from 24-
in piles. Using the monthly activity estimates in hours (table 2) and 
monthly calculated sighting rates (CIBWs/hour) for the spatially 
derived distance bins (table 23), we estimated take by Level B 
harassment for each of the 5 years of the CTR project (table 24).

[[Page 85730]]



   Table 23--Allocation of Each Level B Harassment Isopleth to a Sighting Rate Bin and CIBW Monthly Sighting Rates for Different Pile Sizes and Hammer
                                                                          Types
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Level B                                                             Belugas/Hour
                                           isopleth    Sighting rate bin number  -----------------------------------------------------------------------
                Activity                   distance          and distance
                                             (m)                                    Apr      May      Jun      Jul    Aug \1\  Sep \1\  Oct \1\    Nov
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                Unattenuated Values (without the use of a bubble curtain)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in Vibratory Removal \1\ \2\........        1,699  2 (2,338 m)...............     0.34     0.16     0.15     0.09     1.55     1.42     1.09     0.65
36-in Vibratory Installation \1\ \2\...        4,514  4 (6,974 m)...............     0.67     0.33     0.29     0.13     2.24     2.18     2.42     0.73
72-in Vibratory Installation \3\.......        9,069  5 (>6,974)................     0.71     0.39     0.30     0.13     2.29     2.23     2.56     0.73
Concurrent 36-in AND 36-in Vibratory           9,069
 Installation.
Concurrent 36-in AND 36-in OR 72-in            9,363
 Vibratory Installation \4\.
36-in Impact Installation \1\ \2\......        1,585  2 (2,338 m)...............     0.34     0.16     0.15     0.09     1.55     1.42     1.09     0.65
72-in Impact Installation \3\..........        7,356  5 (>6,974)................     0.71     0.39     0.30     0.13     2.29     2.23     2.56     0.73
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                  Attenuated Values (with the use of a bubble curtain)
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in Vibratory Removal \2\............        1,318  2 (2,338).................     0.34     0.16     0.15     0.09     1.55     1.42     1.09     0.65
36-in Vibratory Installation \2\.......        3,575  4 (6,974 m)...............     0.67     0.33     0.29     0.13     2.24     2.18     2.42     0.73
72-in Vibratory Installation \3\.......        6,119
Concurrent 36-in AND 36-in Vibratory           5,667
 Installation.
Concurrent 36-in AND 72-in Vibratory           8,318  5 (>6,974)................     0.71     0.39     0.30     0.13     2.29     2.23     2.56     0.73
 Installation.
36-in Impact Installation \1\ \2\......          541  2 (2,338).................     0.34     0.16     0.15     0.09     1.55     1.42     1.09     0.65
72-in Impact Installation..............        2,512  3 (3,155 m)...............     0.36     0.22     0.21     0.09     2.02     1.89     1.98     0.72
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Unattenuated vibratory and impact driving of temporary and permanent piles during the months of August through October would be limited to the
  minimum possible number of piles that must be driven in-water in depths <3 m.
\2\ Unattenuated and attenuated vibratory installation of 36-in temporary piles both result in bin 4; vibratory removal of this pile type results in bin
  2 in both attenuated and unattenuated conditions. Unattenuated and attenuated impact pile driving of 36-in piles results in bin 2 in both conditions.
\3\ Unattenuated vibratory and impact installation of permanent (72-in) piles will be minimized to the extent possible by driving as many piles as
  possible in the dry for all months of the construction seasons. To account for piles driven in water less than 3 m deep, NMFS has estimated
  approximately 0.5 unattenuated 72-in piles will be driven (approximately 43 minutes of impact driving and 5 minutes of vibratory driving) each month.
  Impact driving (attenuated and unattenuated) results in Bin 2; vibratory driving (attenuated and unattenuated) results in Bin 5.
\4\ Both concurrent driving of 2 temporary piles (1 attenuated, 1 unattenuated) and 1 temporary (unattenuated) and 1 permanent (attenuated) piles result
  in a Level B harassment isopleth of 9,363 m.

    For the PCT (85 FR 19294, April 6, 2020), SFD (86 FR 50057, 
September 7, 2021), and NES1 (89 FR 2832, January 14, 2024) projects, 
NMFS accounted for the implementation of mitigation measures (e.g., 
shutdown procedures implemented when CIBWs entered or approached the 
estimated Level B harassment zone) by applying an adjustment factor to 
CIBW take estimates. This was based on the assumption that some Level B 
harassment takes would likely be avoided based on required shutdowns 
for CIBWs at the Level B harassment zone isopleths (see the Proposed 
Mitigation section for more information). For the PCT project, NMFS 
compared the number of observations of CIBW within estimated harassment 
zones at the POA to the number of authorized takes for previous 
projects from 2008 to 2017 and found the percentage ranged from 12 to 
59 percent with an average of 36 percent (85 FR 19294, April 6, 2020). 
NMFS then applied the highest percentage of previous potentially 
realized takes (i.e., number of CIBWs observed within estimated Level B 
harassment zones; 59 percent during the 2009-2010 season) to ensure 
potential takes of CIBWs were fully evaluated. In doing so, NMFS 
assumed that approximately 59 percent of the takes calculated could be 
realized during PCT and SFD construction (85 FR 19294, April 6, 2020; 
86 FR 50057, September 7, 2021) and that 41 percent of the calculated 
CIBW Level B harassment takes would be avoided by successful 
implementation of required mitigation measures.
    The POA calculated the adjustment for successful implementation of 
mitigation measures for CTR using the percentage of realized takes for 
the PCT project (see table 6-20 in the POA's application). The data 
from PCT Phase 1 and PCT Phase 2 most accurately reflect the current 
marine mammal monitoring program, the current program's effectiveness, 
and CIBW occurrence in the proposed project area. Between the two 
phases of the PCT project, 90 total Level B harassment takes were 
authorized and 53 were potentially realized, equating to an overall 
percentage of 59 percent. The SFD Project, during which only 7 percent 
of authorized take was potentially realized, represents installation of 
only 12 piles during a limited time period and does not represent the 
much higher number of piles and longer construction timeframe 
anticipated for CTR.
    NMFS proposes that the 59-percent adjustment accurately accounts 
for the efficacy of the POA's marine mammal monitoring program and 
required shutdown protocols, based on past performance. NMFS, 
therefore, assumes that approximately 59 percent of the takes 
calculated for CTR may actually be realized (table 24). Take by Level A 
harassment is not anticipated or proposed to be authorized for CIBWs 
because the POA will be required to shut down activities when CIBWs 
approach and or enter the Level B harassment zone, which in all cases 
is larger than the estimated Level A harassment zones (see the Proposed 
Mitigation section for more information).

                                 Table 24--Calculated Level B harassment Takes of CIBWs by Month, Year, and Activity \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Apr        May        Jun        Jul      Aug \2\    Sep \2\    Oct \2\      Nov
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Year 1 \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
36'' vibratory installation \3\.................................       1.68       2.01       1.76       0.78      13.44      13.10       7.26       1.47
36'' vibratory removal \3\......................................       0.26       0.12       0.11       0.07       1.16       1.06       0.82       0.49

[[Page 85731]]

 
72'' vibratory installation (attenuated)........................       0.50       0.59       0.51       0.23       3.17       3.09       3.43       0.06
72'' vibratory installation (unattenuated) \4\..................       0.06       0.03       0.03       0.01       0.19       0.19       0.21       0.06
72'' impact installation (attenuated)...........................       2.35       3.36       3.19       1.40      24.67      23.08      24.18       3.62
72'' impact installation (unattenuated) \4\.....................       0.49       0.27       0.21       0.09       1.60       1.56       1.79       0.51
                                                                 ---------------------------------------------------------------------------------------
    Year 1 total................................................  .........  .........  .........  .........  .........  .........  .........        151
    With 59% Correction Factor \5\..............................  .........  .........  .........  .........  .........  .........  .........         90
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Year 2 \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
36'' vibratory installation \3\.................................       2.01       1.67       1.47       0.65      11.20      10.91       6.05       1.47
36'' vibratory removal \3\......................................       0.26       0.12       0.11       0.07       1.16       1.06       0.82       0.00
72'' vibratory installation (attenuated)........................       0.50       0.47       0.42       0.18       3.17       2.73       3.03       0.43
72'' vibratory installation (unattenuated) \4\..................       0.06       0.03       0.03       0.01       0.19       0.19       0.21       0.06
72'' impact installation (attenuated)...........................       2.35       2.72       2.58       1.14      24.67      20.36      21.34       3.62
72'' impact installation (unattenuated) \4\.....................       0.49       0.27       0.21       0.09       1.60       1.56       1.79       0.51
                                                                 ---------------------------------------------------------------------------------------
    Year 2 total................................................  .........  .........  .........  .........  .........  .........  .........        137
    With 59% Correction Factor \5\..............................  .........  .........  .........  .........  .........  .........  .........         81
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Year 3 \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
36'' vibratory installation \3\.................................       4.36       4.35       3.82       1.68      29.13      28.38      15.73       1.47
36'' vibratory removal \3\......................................       0.26       0.37       0.34       0.21       2.33       2.12       0.82       0.49
72'' vibratory installation (attenuated)........................       0.39       0.20       0.17       0.05       0.93       0.91       1.01       0.31
72'' vibratory installation (unattenuated) \4\..................       0.06       0.03       0.03       0.01       0.19       0.19       0.21       0.06
72'' impact installation (attenuated)...........................       1.83       1.12       1.07       0.34       7.28       6.81       7.13       2.59
72'' impact installation (unattenuated) \4\.....................       0.49       0.27       0.21       0.09       1.60       1.56       1.79       0.51
                                                                 ---------------------------------------------------------------------------------------
    Year 3 total................................................  .........  .........  .........  .........  .........  .........  .........        136
    With 59% Correction Factor \5\..............................  .........  .........  .........  .........  .........  .........  .........         81
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Year 4 \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
36'' vibratory installation \3\.................................       4.36       4.35       3.82       1.68      29.13      28.38      15.73       1.47
36'' vibratory removal \3\......................................       0.26       0.37       0.34       0.21       2.33       2.12       0.82       0.49
72'' vibratory installation (attenuated)........................       0.39       0.20       0.17       0.05       0.93       0.91       1.01       0.31
72'' vibratory installation (unattenuated) \4\..................       0.06       0.03       0.03       0.01       0.19       0.19       0.21       0.06
72'' impact installation (attenuated)...........................       1.83       1.12       1.07       0.34       7.28       6.81       7.13       2.59
72'' impact installation (unattenuated) \4\.....................       0.49       0.27       0.21       0.09       1.60       1.56       1.79       0.51
                                                                 ---------------------------------------------------------------------------------------
    Year 4 total................................................  .........  .........  .........  .........  .........  .........  .........        138
    With 59% Correction Factor \5\..............................  .........  .........  .........  .........  .........  .........  .........         82
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                       Year 5 \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
36'' vibratory installation \3\.................................       1.68       2.01       1.76       0.78      13.44      12.00      13.31       1.84
36'' vibratory removal \3\......................................       0.26       0.12       0.11       0.07       1.16       1.06       0.82       0.49
72'' vibratory installation (attenuated)........................       0.28       0.47       0.42       0.18       2.80       2.73       3.03       0.31
72'' vibratory installation (unattenuated) \4\..................       0.06       0.03       0.03       0.01       0.19       0.19       0.21       0.06
72'' impact installation (attenuated)...........................       1.31       2.72       2.58       1.14      21.77      20.36      21.34       2.59
72'' impact installation (unattenuated) \4\.....................       0.49       0.27       0.21       0.09       1.60       1.56       1.79       0.51
    Year 5 total................................................  .........  .........  .........  .........  .........  .........  .........        143
    With 59% Correction Factor \5\..............................  .........  .........  .........  .........  .........  .........  .........         85
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Years 1-5 Total
--------------------------------------------------------------------------------------------------------------------------------------------------------
    Project Total Estimated Exposures...........................  .........  .........  .........  .........  .........  .........  .........        705
    With 59% Correction Factor \5\..............................  .........  .........  .........  .........  .........  .........  .........        419
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Concurrent driving scenarios that would improve the production efficiency in the months of April through July have been conservatively excluded from
  this analysis.
\2\ Unattenuated vibratory driving of temporary and permanent piles during the months of August through October would be limited to the minimum possible
  number of piles that must be driven in-water in depths <3m.
\3\ Attenuated and unattenuated bins for this activity are the same.
\4\ Unattenuated vibratory and impact installation of permanent (72-in) piles will be minimized to the extent possible by driving as many piles as
  possible in the dry for all months of the construction seasons. This calculation assumes 0.5 72-in piles per month may be driven in water depths <3m
  and thus be unattenuated.
\5\ Corrected exposure estimates have been rounded up for each year (e.g., Year 1 = 0.59 * 151 = 89.1, which has been rounded up to 90).

    In summary, the maximum annual amount of Level A harassment and 
Level B harassment proposed to be authorized for each marine mammal 
stock is presented in table 25.

[[Page 85732]]



   Table 25--Number of Proposed Takes as a Percentage of Stock Abundance, by Stock and Harassment Type for the
                                  Maximum Annual Estimated Takes of the Project
----------------------------------------------------------------------------------------------------------------
                                                Proposed take
              Species              ---------------------------------------         Stock            Percent of
                                      Level A      Level B       Total                                 stock
----------------------------------------------------------------------------------------------------------------
Gray whale........................            4            2            6  Eastern North Pacific            0.02
Humpback whale \1\................            3            1            4  Hawai[revaps]i.......            0.04
                                                                           Mexico-North Pacific.         \2\ UNK
Beluga whale......................            0           90           90  Cook Inlet \3\.......            27.2
Killer whale \1\..................            6            6           12  Eastern North Pacific             0.6
                                                                            Alaska Resident.
                                                                           Eastern North Pacific            2.04
                                                                            Gulf of Alaska,
                                                                            Aleutian Islands and
                                                                            Bering Sea Transient.
Harbor porpoise...................           16            8           24  Gulf of Alaska.......            0.08
Steller sea lion..................            6            3            9  Western..............           0.015
Harbor seal.......................           99           55          154  Cook Inlet/Shelikof              0.54
                                                                            Strait.
----------------------------------------------------------------------------------------------------------------
\1\ NMFS conservatively assumes that all takes occur to each stock
\2\ NMFS does not have an official abundance estimate for this stock and the minimum population estimate is
  considered to be unknown (Young et al., 2023). See Small Numbers for additional discussion.
\3\ This abundance estimate is from Goetz et al. (2023); which was published after the most recent CIBW SAR
  (Young et al., 2023).

Proposed Mitigation

    In order to promulgate a rulemaking under section 101(a)(5)(A) of 
the MMPA, NMFS must set forth the permissible methods of taking 
pursuant to the activity and other means of effecting the least 
practicable adverse 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, NMFS 
considers two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
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 factors such as cost and impact on 
operations.
    The POA presented mitigation measures in section 11 of their 
application that were modeled after the requirements included in the 
IHAs issued for Phase 1 and Phase 2 PCT construction (85 FR 19294, 
April 6, 2020) and for SFD construction (86 FR 50057, September 7, 
2021), which were designed to minimize the total number, intensity, and 
duration of harassment events for CIBWs and other marine mammal species 
during those projects (61N Environmental, 2021, 2022a, 2022b). NMFS 
concurs that these proposed measures reduce the potential for CIBWs and 
other marine mammals to be adversely impacted by the proposed activity.
    Noise Mitigation for Pile Installation and Removal--The POA has 
previously utilized and assessed the effectiveness of bubble curtains 
for noise mitigation at the project site (Austin et al. 2016; 
Illingworth and Rodkin, LLC (I&R) 2021a, 2021b, 2023). In all previous 
years of the PAMP, bubble curtains were not used on piles installed or 
removed in shallow water less than 3 meters deep or piles installed or 
removed ``in the dry'' (e.g., at times when the tide is low and the 
pile's location is dewatered) because low water levels prevent proper 
deployment and function of a bubble curtain system. When a pile was 
installed or removed in the dry, it was assumed that no exposure to 
received sound levels equated with potential incidental harassment 
occurred and, therefore, that no take of marine mammals occurred. The 
same assumptions and approach to mitigation associated with use of a 
bubble curtain have been used in the analyses for this project.
    NMFS is proposing that the POA must employ the following mitigation 
measures:
    <bullet> Ensure that construction supervisors and crews, the 
monitoring team and relevant POA staff are trained prior to the start 
of all pile driving, so that responsibilities, communication 
procedures, monitoring protocols, and operational procedures are 
clearly understood. New personnel joining during the project must be 
trained prior to commencing work;
    <bullet> Employ PSOs and establish monitoring locations as 
described in the POA's Marine Mammal Monitoring and Mitigation Plan 
(see appendix B of the POA's application). The POA must monitor the 
project area to the maximum extent possible based on the required 
number of PSOs, required monitoring locations, and environmental 
conditions;
    <bullet> Monitoring must take place from 30 minutes prior to 
initiation of pile driving (i.e., pre-clearance monitoring) through 30 
minutes post-completion of pile driving;
    <bullet> Pre-start clearance monitoring must be conducted during 
periods of visibility sufficient for the lead PSO to determine that the 
shutdown zones indicated in table 26 are clear of marine mammals. Pile 
driving may commence following 30 minutes of observation when the 
determination is made that the shutdown zones are clear of marine 
mammals or when the mitigation measures proposed specifically for CIBWs 
(below) are satisfied;
    <bullet> If work ceases for more than 30 minutes, PSOs must observe 
a 30-minute pre-start clearance period (i.e.,

[[Page 85733]]

the shutdown zones must be observed for 30 minutes and confirmed clear 
of marine mammals) prior to reinitiating pile driving. A determination 
that the shutdown zone is clear must be made during a period of good 
visibility.
    <bullet> For all construction activities, shutdown zones must be 
established following table 26. The purpose of a shutdown zone is 
generally to define an area within which shutdown of activity would 
occur upon sighting of a marine mammal entering or within the defined 
area. The shutdown zones (table 26) were calculated based on the 
minimum 100-m shutdown zone proposed by the POA for all pile 
installation and vibratory extraction activities, as well as the 
calculated Level A (non-CIBW species) and Level B (CIBWs) harassment 
isopleths shown in table 16. In most cases, the shutdown zones exceed 
the calculated Level A isopleths; exceptions occur during impact pile 
driving, when the calculated Level A harassment isopleths exceed 
practicable shutdown zones for non-CIBW species, and during concurrent 
vibratory driving (the largest Level A isopleth is 161 m during this 
activity). For CIBWs, the shutdown zones exceed the calculated Level B 
harassment isopleths in all scenarios.

                                              Table 26--Proposed Shutdown Zones During Specified Activities
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                           Shutdown zone (m)
                                                              Attenuated or   --------------------------------------------------------------------------
           Activity                   Pile type/size           unattenuated         LF       Non-CIBW MF \1\                  HF \1\
                                                                                cetaceans       cetaceans        CIBWs      cetaceans      PW       OW
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Installation........  24-in.....................  Unattenuated.....          100               100        2,250          100      100      100
                                36-in.....................                                                          4,520
                                72-in.....................  .................
                                72-in.....................                                                          9,100
                                24-in.....................  Attenuated.......                                       2,630
                                36-in.....................                                                          3,580
                                72-in.....................                                                          6,120
Vibratory Removal.............  24-in.....................  Unattenuated.....                                       5,970
                                36-in.....................                                                          1,700
                                24-in.....................  Attenuated.......                                       2,100
                                36-in.....................                                                          1,320
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation--1 pile     24-in.....................  Unattenuated.....          500               500        1,600          500      100      100
 per day.                       36-in.....................
                                24-in.....................  Attenuated.......          100               100          550          100      100      100
                                36-in.....................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation--1 pile     72-in.....................  Unattenuated.....          500               500        7,360          500      100      100
 per day.
                                                            Attenuated.......                                       2,520
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact Installation--2 piles
 per day.
Impact Installation--3 piles
 per day.
Concurrent--2 Vibratory         36-in.....................  Attenuated/                100               100        5,670          100      100      100
 sources.                       AND.......................   Attenuated.                                            9,370
                                36-in.....................  Attenuated/                                             9,070
                                                             Unattenuated.
                                                            Unattenuated/
                                                             Unattenuated.
                                36-in.....................  Attenuated/                                             8,320
                                AND.......................   Attenuated.                                            9,370
                                72-in.....................  Unattenuated/
                                                             Attenuated.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Concurrent Vibratory/Impact...  36-in.....................  Attenuated/                500               500        3,580          500      100      100
                                AND.......................   Attenuated (1
                                72-in.....................   pile per day).
                                                            Attenuated/
                                                             Attenuated (2
                                                             piles per day).
                                                            Attenuated/
                                                             Attenuated (3
                                                             piles per day).
                                                            Unattenuated/                                           4,520
                                                             Attenuated (1
                                                             pile per day).
                                                            Unattenuated/
                                                             Attenuated (2
                                                             piles per day).
                                                            Unattenuated/
                                                             Attenuated (3
                                                             piles per day).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes: cm = centimeter(s), m = meter(s); POA may elect to use either 36-in or 24-in temporary piles; as 36-in piles are more likely and estimated to
  have larger ensonified areas, we have used these piles in our analyses of concurrent activities.
\1\ In the Updated Technical Guidance (NMFS, 2024), the MF Cetacean hearing group has been re-named the HF Cetacean group; HF Cetaceans from the 2018
  Technical Guidance have been re-named VHF Cetaceans.

    <bullet> Marine mammals observed anywhere within visual range of 
the PSO must be tracked relative to construction activities. If a 
marine mammal is observed entering or within the shutdown zones 
indicated in table 26, pile driving must be delayed or halted. If pile 
driving is delayed or halted due to the presence of a marine mammal, 
the activity may not commence or resume until either the animal has 
voluntarily exited and been visually confirmed beyond the shutdown zone 
(table 26), or 15 minutes (non-CIBWs) or 30 minutes (CIBWs) have passed 
without re-detection of the animal;
    <bullet> The POA must use bubble curtains for all piles during both 
vibratory and impact pile driving in water depths greater than 3 m 
during the months of August through October. No bubble curtain is 
required for vibratory pile driving of temporary (24-in or 36-in) piles 
in the months of April-July (see discussion below). Bubble curtains 
must

[[Page 85734]]

be used for all permanent (72-in) piles during both vibratory and 
impact pile driving in waters deeper than 3 m in the months of April-
November. The bubble curtain must be operated as necessary to achieve 
optimal performance. At a minimum, the bubble curtain must distribute 
air bubbles around 100 percent of the piling circumference for the full 
depth of the water column; the lowest bubble ring must be in contact 
with the substrate for the full circumference of the ring; and air flow 
to the bubblers must be balanced around the circumference of the pile.
    <bullet> The 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 30-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 
30 minutes or longer. PSOs shall begin observing for marine mammals 30 
minutes before ``soft start'' or in-water pile installation or removal 
begins;
    <bullet> Pile driving activity must be halted upon observation of 
either a species for which incidental take is not authorized or a 
species for which incidental take has been authorized but the 
authorized number of takes has been met, entering or within the 
harassment zone; and
    <bullet> The POA must avoid direct physical interaction with marine 
mammals during non-pile-driving construction activities, including 
barge positioning and pile cutting. If a marine mammal comes within 10 
m of such activity, operations shall cease. Should a marine mammal come 
within 10 m of a vessel in transit, the boat operator will reduce 
vessel speed to the minimum level required to maintain steerage and 
safe working conditions. If human safety is at risk, based on the best 
judgment of the vessel captain or project engineer, the in-water 
activity is allowed to continue until it is safe to stop.
    The following additional mitigation measures are proposed by NMFS 
for CIBWs:
    <bullet> Prior to the onset of pile driving, should a CIBW be 
observed approaching the estimated shutdown zone (table 26) (i.e. the 
CIBWs Level B harassment zone column in tables 15 and 16), pile driving 
must not commence until the whale(s) moves at least 100 m past the 
estimated shutdown zone and on a path away from the zone, or the whale 
has not been re-sighted within 30 minutes;
    <bullet> If pile installation or removal has commenced and a 
CIBW(s) is observed within or likely to enter the shutdown zone, pile 
installation or removal must shut down and not re-commence until the 
whale has traveled at least 100 m beyond the shutdown zone and is on a 
path away from such zone or until no CIBW has been observed in the 
shutdown zone for 30 minutes; and
    <bullet> If during installation and removal of piles, PSOs can no 
longer effectively monitor the entirety of the CIBW shutdown zone due 
to environmental conditions (e.g., fog, rain, wind), pile driving may 
continue only until the current segment of the pile is driven; no 
additional sections of pile or additional piles may be driven until 
conditions improve such that the shutdown zone can be effectively 
monitored. If the shutdown zone cannot be monitored for more than 15 
minutes, the entire shutdown zone will be cleared again for 30 minutes 
prior to pile driving.
    In addition to these mitigation measures being proposed by NMFS, 
NMFS requested that the POA restrict all pile driving and removal work 
to April to July, when CIBWs are typically found in lower numbers. 
However, the POA stated that given the scale of the project, 
construction sequencing requirements, critical nature of the CTR 
infrastructure and overall PAMP, and vulnerability of the existing 
cargo terminals to seismic events, it cannot commit to restricting pile 
driving and removal to April to July. Instead, the POA would complete 
as much work as is practicable in April to July to reduce the amount of 
pile driving and removal activities in August through November. The POA 
is aware that August through October are months with high CIBW 
abundance and plans to complete in-water work as early in the 
construction season as possible. The POA also recognizes that more work 
shutdowns for CIBW are likely to take place in high abundance months, 
which provides incentive to complete work earlier in the season.
    Due to the deterioration of the current facilities and complexity 
of the PAMP, it is important that the POA attempt to complete the CTR 
project as currently proposed (6 years in total), which requires the 
POA to make full use of the available annual construction window 
(August through October/November). Potential consequences of pausing 
the construction season (e.g., stopping work from August through 
October) include de-rating of the structural capacity of the existing 
cargo terminals, a shutdown of dock operations due to deteriorated 
conditions, or an actual collapse of one or more dock structures. The 
potential for collapse increases with schedule delays due to both 
worsening deterioration and the higher probability of a significant 
seismic event occurring before T1 and T2 replacement.
    For previous IHAs issued to the POA (PCT: 85 FR 19294, April 6, 
2020; SFD: 86 FR 50057, September 7, 2021), the use of a bubble curtain 
to reduce noise has been required as a mitigation measure for certain 
pile driving scenarios. The POA has concerns about effectiveness of 
bubble curtains in the far-field during vibratory pile driving (see 
Appendix A of the POA's application for further details). NMFS 
disagrees with the POA's assertion of effectiveness but acknowledges 
the use of bubble curtains on all piles has the potential to drive the 
in-water construction schedule further into the late summer months, 
which are known for higher CIBW abundance in the project area, thus 
lengthening the duration of potential interactions between CIBW and in-
water work. Therefore, NMFS is concerned that use of a bubble curtain 
for all piles in all months may ultimately result in increased impacts 
to CIBW. Given the extensive proposed visual monitoring and mitigation 
measures in place, and in order to facilitate increased production when 
CIBW abundance at POA is expected to be lowest, NMFS concurs that the 
POA's proposal to use vibratory hammers to install and extract 
temporary piles with no bubble curtain during the months of April 
through July affects the least practicable adverse impact on marine 
mammals. A bubble curtain would be required during all installation of 
permanent piles in all months, and for vibratory driving of temporary 
piles in August through October.
    NMFS considered additional mitigation and monitoring requirements 
for the CTR project, including sound-source verification measurements 
and passive acoustic monitoring of marine mammals near the POA. Sound 
source verification is time-intensive and expensive, and the POA has 
previously collected data on most of the pile types proposed for the 
CTR project (Illingworth and Rodkin, 2021a, b). Following discussion 
with the POA, NMFS determined that conducting additional sound source 
verification measurements would not be practicable or provide support 
for additional mitigation value due to schedule concerns and the volume 
of data already collected and, therefore, this measure was eliminated 
from the suite of proposed mitigation requirements. However, depending 
on future project conditions, the POA may choose to conduct sound 
source verification measurements and work with NMFS to

[[Page 85735]]

revise the estimated harassment zones as indicated by the data 
collected.
    With respect to passive acoustic monitoring, available technologies 
to detect marine mammals in near real-time require a surface buoy for 
the device, and mooring locations would be limited by ongoing port 
operations, construction activities, and dredging. The high noise 
environment at the POA (from both anthropogenic and natural sources) 
would add additional limitations to the detection range of such 
devices. Therefore, NMFS believes that the POA's extensive and 
successful visual monitoring program represents the best possible 
method of minimizing effects to marine mammals, including CIBWs to pile 
driving noise, and that passive acoustic monitoring would not provide 
additional benefits to marine mammals in this case.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
affecting 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 promulgate a rulemaking for an activity, section 
101(a)(5)(A) 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 specified geographical region. Effective reporting is 
critical both to compliance as well as ensuring that the most value is 
obtained from the required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
    <bullet> Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
    <bullet> Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the activity; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
    <bullet> Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
    <bullet> How anticipated responses to stressors impact either: (1) 
long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
    <bullet> Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and,
    <bullet> Mitigation and monitoring effectiveness.
    The POA's draft Marine Mammal Monitoring and Mitigation Plan is 
Appendix B of the LOA application, and is available on regulations.gov 
and at https://www.fisheries.noaa.gov/action/incidental-take-authorization-port-alaskas-construction-activities-port-alaska-modernization. The POA proposes to implement a marine mammal monitoring 
and mitigation strategy intended to avoid and minimize impacts to 
marine mammals. Marine mammal monitoring would be conducted at all 
times when in-water pile installation and removal is taking place. 
Prior to the beginning of construction, POA would submit a revised 
Marine Mammal Mitigation and Monitoring Plan containing additional 
details of monitoring locations and methodology for NMFS concurrence.
    The marine mammal monitoring and mitigation program that is planned 
for CTR construction would be modeled after the successful monitoring 
and mitigation programs outlined in the IHAs for Phase 1 and Phase 2 
PCT construction (85 FR 19294, April 6, 2020) and the IHAs for SFD (86 
FR 50057, September 7, 2021) and NES1 (89 FR 2832, January 14, 2024) 
construction. These monitoring programs have provided the best 
available data on CIBW and other marine mammal presence at the POA and 
continue to be used successfully as of July 2024 at the NES1 project.

Visual Monitoring

    Monitoring must be conducted by qualified, NMFS-approved PSOs, in 
accordance with the following:
    <bullet> PSOs must be independent of the activity contractor (e.g., 
employed by a subcontractor) and have no other assigned tasks during 
monitoring periods. At least one PSO at each monitoring station must 
have prior experience performing the duties of a PSO during 
construction activity pursuant to a NMFS-issued ITA or Letter of 
Concurrence. Other PSOs may substitute other relevant experience 
(including relevant Alaska Native traditional knowledge), education 
(degree in biological science or related field), or training for prior 
experience performing the duties of a PSO. PSOs must be approved by 
NMFS prior to beginning any activity subject to this ITA;
    <bullet> The POA must employ PSO stations at a minimum of four 
locations from which PSOs can effectively monitor the shutdown zones 
(table 24). PSO stations must be positioned at the best practical 
vantage points that are determined to be safe. Likely locations include 
the Anchorage Downtown Viewpoint near Point Woronzof, the Anchorage 
Public Boat Dock at Ship Creek, the CTR Project site, and the North End 
of POA property (see figure 13-1 in the POA's application for potential 
locations of PSO stations). Areas near Cairn Point or Port MacKenzie 
have safety, security, and logistical issues, which would need to be 
considered. Cairn Point proper is located on military land and has bear 
presence, and restricted access does not allow for the location of an 
observation station at this site. Tidelands along Cairn Point are 
accessible only during low tide conditions and have inherent safety 
concerns of being trapped by rising tides. Port MacKenzie is a secure 
port that is relatively remote, creating safety, logistical, and 
physical staffing limitations due to lack of nearby lodging and other 
facilities. The roadway travel time between port sites is approximately 
2-3 hours. An additional possible monitoring location is proposed north 
of the proposed project site, pending selection of the Construction 
Contractor and more detailed discussions before the start of 
construction. Temporary staffing of a northerly monitoring station 
during peak marine mammal presence time periods and/or when shutdown 
zones are large would be considered by the POA, NMFS, and the 
construction contractor based on evaluation of CIBW occurrence reported 
in the required weekly monitoring reports. At least one PSO station 
must be able to fully observe the non-CIBW shutdown zones; multiple PSO 
stations will be necessary to fully observe the CIBW shutdown zones 
(table 24);
    <bullet> PSO stations must be elevated platforms constructed on top 
of shipping containers or a similar base

[[Page 85736]]

that is at least 8'6'' high (i.e., the standard height of a shipping 
container) that can support at least three PSOs and their equipment. 
The platforms must be stable enough to support use of a theodolite and 
must be located to optimize the PSO's ability to observe marine mammals 
and the harassment zones;
    <bullet> Each PSO station must have at least two PSOs on watch at 
any given time; one PSO must be observing and one PSO would be 
recording data (and observing when there are no data to record). Teams 
of three PSOs would include one PSO who would be observing, and one PSO 
who would be recording data (and observing when there are no data to 
record). The third PSO may help to observe, record data, or rest. In 
addition, if POA is conducting in-water work on other projects that 
includes PSOs, the CTR 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;
    <bullet> A designated lead PSO must always be on site. The lead 
observer must have prior experience performing the duties of a PSO 
during in-water construction activities pursuant to a NMFS-issued ITA 
or Letter of Concurrence. Each PSO station must also have a designated 
Station Lead PSO specific to that station and shift. These Station Lead 
PSOs must have prior experience working as a PSO during in-water 
construction activities;
    <bullet> PSOs would use a combination of equipment to perform 
marine mammal observations and to verify the required monitoring 
distance from the project site, which may include 7 by 50 binoculars, 
20x/40x tripod mounted binoculars, 25 by 150 ``big eye'' tripod mounted 
binoculars, and theodolites;
    <bullet> PSOs must record all observations of marine mammals, 
regardless of distance from the pile being driven. PSOs shall document 
any behavioral reactions in concert with distance from piles being 
driven or removed;
    PSOs must have the following additional qualifications:
    <bullet> Ability to conduct field observations and collect data 
according to assigned protocols;
    <bullet> Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
    <bullet> Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    <bullet> Writing skills sufficient to record required information 
including but not limited to the number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates, times, and reason for implementation of mitigation 
(or why mitigation was not implemented when required); and marine 
mammal behavior; and
    <bullet> Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.

Reporting

    NMFS would require the POA to submit interim weekly monitoring 
reports within 14 calendar days after the conclusion of each calendar 
week (that include raw electronic data sheets) during the CTR 
construction seasons, including for weeks during which no in-water work 
occurred (an email notification for weeks with no in-water work would 
be sufficient). These reports must include a summary of marine mammal 
species observed and behavioral observations, mitigation actions 
implemented, construction delays, and construction work completed. They 
also must include an assessment of the amount of construction remaining 
to be completed (i.e., the number of estimated hours of work 
remaining), in addition to the number of CIBWs observed within 
estimated harassment zones to date for the current construction year.
    NMFS would also require the POA to submit annual reports after the 
end of each construction season and a comprehensive final report 
following the conclusion of year 5 construction activities. Draft 
annual marine mammal monitoring reports must be submitted to NMFS 
within 90 days after the completion of each construction season or 60 
days prior to a requested date of issuance of any future incidental 
take authorization for projects at the same location, whichever comes 
first. Annual reports must detail the monitoring protocol and summarize 
the data recorded during monitoring, and associated PSO data sheets in 
electronic tabular format. Specifically, the reports must include:
    <bullet> Dates and times (begin and end) of all marine mammal 
monitoring;
    <bullet> Construction activities occurring during each daily 
observation period, including the number and type of piles driven or 
removed and by what method (i.e., impact or vibratory, the total 
equipment duration for vibratory installation and removal, and the 
total number of strikes for each pile during impact driving);
    <bullet> PSO locations during marine mammal monitoring;
    <bullet> Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), including Beaufort sea state and any other relevant 
weather conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance;
    <bullet> Upon observation of a marine mammal, the following 
information: name of PSO who sighted the animal(s) and PSO location and 
activity at time of sighting; time of sighting; identification of the 
animal(s) (e.g., genus/species, lowest possible taxonomic level, or 
unidentified), PSO confidence in identification, and the composition of 
the group if there is a mix of species; distance and bearing of each 
marine mammal observed relative to the pile being driven for each 
sighting (if pile driving was occurring at time of sighting); estimated 
number of animals (minimum, maximum, and best estimate); estimated 
number of animals by cohort (adults, juveniles, neonates, group 
composition, sex class, etc.); animal's closest point of approach and 
estimated time spent within the harassment zone; group spread and 
formation (for CIBWs only; see ethogram in Appendix B of the POA's 
application); description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses that may have resulted from the 
activity (e.g., no response or changes in behavioral state such as 
ceasing feeding, changing direction, flushing, or breaching);
    <bullet> Number of marine mammals detected within the harassment 
zones, by species;
    <bullet> Detailed information about any implementation of 
mitigation action (e.g., shutdowns and delays), a description of 
specific actions that ensued, and resulting changes in behavior of the 
animal(s), if any;
    If no comments are received from NMFS within 30 days, the draft 
annual or comprehensive reports would constitute the final reports. If 
comments are received, a final report addressing NMFS comments must be 
submitted within 30 days after receipt of comments.

Reporting Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the POA must immediately 
cease the specified activities and report the incident to the Office of 
Protected Resources, NMFS

[[Page 85737]]

(<a href="/cdn-cgi/l/email-protection#78282a56312c2856351716110c170a11161f2a1d08170a0c0b3816171919561f170e"><span class="__cf_email__" data-cfemail="3c6c6e1275686c127153525548534e55525b6e594c534e484f7c52535d5d125b534a">[email protected]</span></a>, <a href="/cdn-cgi/l/email-protection#fbb2afabd593948f9893909295bb95949a9ad59c948d"><span class="__cf_email__" data-cfemail="317865611f595e4552595a585f715f5e50501f565e47">[email protected]</span></a>) and to the 
Alaska Regional Stranding Coordinator as soon as feasible. If the death 
or injury was clearly caused by the specified activity, the POA must 
immediately cease the specified activities until NMFS is able to review 
the circumstances of the incident and determine what, if any, 
additional measures are appropriate to ensure compliance with the terms 
of the IHA. The POA must not resume their activities until notified by 
NMFS. The report must include the following information:
    <bullet> Time, date, and location (latitude and longitude) of the 
first discovery (and updated location information if known and 
applicable);
    <bullet> Species identification (if known) or description of the 
animal(s) involved;
    <bullet> Condition of the animal(s) (including carcass condition if 
the animal is dead);
    <bullet> Observed behaviors of the animal(s), if alive;
    <bullet> If available, photographs or video footage of the 
animal(s); and
    <bullet> General circumstances under which the animal was 
discovered.

Adaptive Management

    These proposed regulations governing the take of marine mammals 
incidental to POA's CTR construction activities contain an adaptive 
management component. Our understanding of the effects of pile driving 
and other coastal construction activities (e.g., acoustic stressors) on 
marine mammals continues to evolve, which makes the inclusion of an 
adaptive management component both valuable and necessary within the 
context of 5-year regulations.
    The monitoring and reporting requirements are associated with 
information that helps us to better understand the impacts of the 
project's activities on marine mammals and informs our consideration of 
whether any changes to mitigation and monitoring are appropriate. The 
use of adaptive management allows NMFS to consider new information from 
different sources to determine (with input from the POA regarding 
practicability) if such modifications will have a reasonable likelihood 
of more effectively accomplishing the goals of the measures.
    The following are some of the possible sources of applicable data 
to be considered through the adaptive management process: (1) results 
from monitoring reports, including the weekly, situational, and annual 
reports required; (2) results from research on marine mammals, noise 
impacts, or other related topics; and (3) any information which reveals 
that marine mammals may have been taken in a manner, extent, or number 
not authorized by these regulations or LOAs issued pursuant to these 
regulations. Adaptive management decisions may be made at any time, as 
new information warrants it.

Negligible Impact Analysis and Determination

    NMFS has defined negligible impact as an impact resulting from the 
specified activity that cannot be reasonably expected to, and is not 
reasonably likely to, adversely affect the species or stock through 
effects on annual rates of recruitment or survival (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of takes alone is not enough 
information on which to base an impact determination. In addition to 
considering estimates of the number of marine mammals that might be 
``taken'' through harassment, NMFS considers other factors, such as the 
likely nature of any impacts or responses (e.g., intensity, duration), 
the context of any impacts or responses (e.g., critical reproductive 
time or location, foraging impacts affecting energetics), as well as 
effects on habitat, and the likely effectiveness of the mitigation. We 
also assess the number, intensity, and context of estimated takes by 
evaluating this information relative to population status. Consistent 
with the 1989 preamble for NMFS' implementing regulations (54 FR 40338, 
September 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the baseline (e.g., as reflected in the regulatory status of 
the species, population size and growth rate where known, ongoing 
sources of human-caused mortality, or ambient noise levels).
    To avoid repetition, this introductory discussion of our analysis 
applies to all the species listed in table 25 except CIBWs given that 
many of the anticipated effects of this project on different marine 
mammal stocks 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 the population, or 
impacts on habitat; therefore, we provide a separate detailed analysis 
for CIBWs following the analysis for other species for which we propose 
to authorize incidental 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 potential effects of the specified activities on gray whales, 
humpback whales, killer whales, harbor porpoises, Steller sea lions, 
and harbor seals are discussed below. Some of these factors also apply 
to CIBWs; however, a more detailed analysis for CIBWs is provided in a 
separate subsection below.
    Species Other than CIBW. Pile driving associated with the project, 
as outlined previously, has the potential to disturb or displace marine 
mammals. Specifically, the specified activities may result in take, in 
the form of Level B harassment and, for some species, Level A 
harassment, from underwater sounds generated by pile driving. Potential 
takes could occur if marine mammals are present in zones ensonified 
above the thresholds for Level B harassment or Level A harassment, 
identified above, while activities are underway.
    The POA's proposed activities and associated impacts would occur 
within a limited, confined area of the stocks' range (other than CIBW). 
The work would occur in the vicinity of the CTR site, and sound from 
the proposed activities would be blocked by the coastline along Knik 
Arm along the eastern boundaries of the site and for those harassment 
isopleths that extend more than 3,000 m, directly across the Arm along 
the western shoreline (see figures 6-10 and 6-11 in the POA's 
application)). The intensity and duration of take by Level A and Level 
B harassment would be minimized through use of mitigation measures 
described herein. Further, the number of takes proposed to be 
authorized is small when compared to stock abundance (see table 25). In 
addition, NMFS does not anticipate that serious injury or mortality 
will occur as a result of the POA's planned activity given the nature 
of the activity, even in the absence of required mitigation.
    Exposures to elevated sound levels produced during pile driving may 
cause behavioral disturbance of some individuals. Behavioral responses 
of marine mammals to pile driving at the proposed project site are 
expected to be mild, short term, and temporary. Effects on individuals 
that are taken by Level

[[Page 85738]]

B harassment, as enumerated in the Estimated Take section, on the basis 
of reports in the literature as well as monitoring from other similar 
activities at the POA and elsewhere, will likely be limited to 
reactions such as increased swimming speeds, increased surfacing time, 
or decreased foraging if such activity were occurring (e.g., Ridgway et 
al., 1997; Nowacek et al., 2007; Thorson and Reyff, 2006; Kendall and 
Cornick, 2015; Goldbogen et al., 2013b; Blair et al., 2016; Wisniewska 
et al., 2018; Piwetz et al., 2021). Marine mammals within the Level B 
harassment zones may not show any visual cues they are disturbed by 
activities or they could become alert, avoid the area, leave the area, 
or display other mild responses that are not visually observable such 
as exhibiting increased stress levels (e.g., Rolland et al. 2012; 
Lusseau, 2005; Bejder et al., 2006; Rako et al., 2013; Pirotta et al., 
2015b; P[eacute]rez-Jorge et al., 2016). They may also exhibit 
increased vocalization rates, louder vocalizations, alterations in the 
spectral features of vocalizations, or a cessation of communication 
signals (Hotchkin and Parks 2013). However, as described in the 
Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat section of this proposed rule, marine mammals, except CIBWs, 
observed within Level A and Level B harassment zones related to recent 
POA construction activities have not shown any acute, visually 
observable reactions to pile driving activities that have occurred 
during the PCT and SFD projects (61N Environmental, 2021, 2022a, 
2022b).
    Some of the species present in the region will only be present 
temporarily based on seasonal patterns or during transit between other 
habitats. These temporarily present species will be exposed to even 
smaller periods of noise-generating activity, further decreasing the 
impacts. Most likely, individual animals will simply move away from the 
sound source and be temporarily displaced from the area. Takes may also 
occur during important feeding times. The project area though 
represents a small portion of available foraging habitat and impacts on 
marine mammal feeding for all species is expected to be minimal.
    The activities analyzed here are similar to numerous other 
construction activities conducted in Southern Alaska (e.g., 86 FR 
43190, August 6, 2021; 87 FR 15387, March 18, 2022), including the PCT 
and SFD projects within Upper Knik Arm (85 FR 19294, April 6, 2020; 86 
FR 50057, September 7, 2021, respectively) which have taken place with 
no known long-term adverse consequences from behavioral harassment. Any 
potential reactions and behavioral changes are expected to subside 
quickly when the exposures cease, and therefore, no long-term adverse 
consequences are expected (e.g., Graham et al., 2017). While there are 
no long-term peer-reviewed studies of marine mammal habitat use at the 
POA, studies from other areas indicate that most marine mammals would 
be expected to have responses on the order of hours to days. For 
example, harbor porpoises returned to a construction area between pile-
driving events within several days during the construction of offshore 
wind turbines near Denmark (Carstensen et al., 2006). The intensity of 
Level B harassment events would be minimized through use of mitigation 
measures described herein, which were not quantitatively factored into 
the take estimates. The POA would use PSOs stationed strategically to 
increase detectability of marine mammals during in-water construction 
activities, enabling a high rate of success in implementation of 
shutdowns to avoid or minimize injury for most species. Further, given 
the absence of any major rookeries and haulouts within the estimated 
harassment zones, we assume that potential takes by Level B harassment 
would have an inconsequential short-term effect on individuals and 
would not result in population-level impacts.
    As stated in the mitigation section, the POA will implement 
shutdown zones (table 26) that equal or exceed the Level A harassment 
isopleths (table 16) for most vibratory pile driving and maximize 
practicability for shutdowns during impact pile driving. Take by Level 
A harassment is proposed for authorization for some species (gray 
whales, humpback whales, killer whales, harbor seals, Steller sea 
lions, and harbor porpoises) to account for the large Level A 
harassment zones from impact driving and the potential that an animal 
could enter and remain unobserved within the estimated Level A 
harassment zone for a duration long enough to incur auditory injury. 
Any take by Level A harassment is expected to arise from, at most, a 
small degree of auditory injury because animals would need to be 
exposed to higher levels and/or longer duration than are expected to 
occur here in order to incur any more than a small degree of auditory 
injury.
    Due to the levels and durations of likely exposure, animals that 
experience auditory injury will likely only receive slight injury 
(i.e., minor degradation of hearing capabilities within regions of 
hearing that align most completely with the frequency range of the 
energy produced by POA's proposed in-water construction activities 
(i.e., the low-frequency region below 2 kHz)), not severe hearing 
impairment or impairment in the ranges of greatest hearing sensitivity. 
If hearing impairment does occur, it is most likely that the affected 
animal will lose a few dBs in its hearing sensitivity, which, in most 
cases, is not likely to meaningfully affect its ability to forage and 
communicate with conspecifics. There are no data to suggest that a 
single instance in which an animal incurs auditory injury (or TTS) 
would result in impacts to reproduction or survival. If auditory injury 
were to occur, it would be minor and unlikely to affect more than a few 
individuals. Additionally, and as noted previously, some subset of the 
individuals that are behaviorally harassed could also simultaneously 
incur some small degree of TTS for a short duration of time. Because of 
the small degree anticipated, though, any auditory injury or TTS 
potentially incurred here is not expected to adversely impact 
individual fitness, let alone annual rates of recruitment or survival 
for the affected species or stocks.
    Repeated, sequential exposure to pile driving noise over a long 
duration could result in more severe impacts to individuals that could 
affect a population (via sustained or repeated disruption of important 
behaviors such as feeding, resting, traveling, and socializing; 
Southall et al., 2007). Alternatively, marine mammals exposed to 
repetitious construction sounds may become habituated, desensitized, or 
tolerant after initial exposure to these sounds (reviewed by Richardson 
et al., 1995; Southall et al., 2007). However, given the relatively low 
abundance of marine mammals other than CIBWs in Knik Arm compared to 
the stock sizes (table 25), population-level impacts are not 
anticipated. The absence of any pinniped haulouts or other known non-
CIBW home-ranges in the proposed action area further decreases the 
likelihood of population-level impacts.
    The CTR project is also not expected to have significant adverse 
effects on any marine mammal habitat. The project activities would 
occur mostly within the same footprint as existing marine 
infrastructure; the new T1 and T2 would extend approximately 140 ft 
(47-m) seaward of the existing terminals. The long-term impact on 
marine mammals associated with CTR would be a small permanent decrease 
in low-quality potential habitat because of the expanded footprint of 
the new cargo terminals T1 and T2. Installation and removal of in-water 
piles would be

[[Page 85739]]

temporary and intermittent, and the increased footprint of the 
facilities would destroy only a small amount of low-quality habitat, 
which currently experiences high levels of anthropogenic activity. 
Impacts to the immediate substrate are anticipated, but these would be 
limited to minor, temporary suspension of sediments, which could impact 
water quality and visibility for a short amount of time but which would 
not be expected to have any effects on individual marine mammals. 
Further, there are no known BIAs near the project zone, except for 
CIBWs, that will be impacted by the POA's planned activities.
    Impacts to marine mammal prey species are also expected to be minor 
and temporary and to have, at most, short-term effects on foraging of 
individual marine mammals and likely no effect on the populations of 
marine mammals as a whole. Overall, the area impacted by the CTR 
project is very small compared to the available surrounding habitat and 
does not include habitat of particular importance. The most likely 
impact to prey would be temporary behavioral avoidance of the immediate 
area. During construction activities, it is expected that some fish and 
marine mammals would temporarily leave the area of disturbance, thus 
impacting marine mammals' foraging opportunities in a limited portion 
of their foraging range. But, because of the relatively small area of 
the habitat that may be affected and lack of any habitat of particular 
importance, the impacts to marine mammal habitat are not expected to 
cause significant or long-term negative consequences.
    In summary, the following factors primarily support our preliminary 
negligible impact determinations for the affected stocks of gray 
whales, humpback whales, killer whales, harbor porpoises, Steller sea 
lions, and harbor seals:
    <bullet> No takes by mortality or serious injury are anticipated or 
proposed for authorization;
    <bullet> Any acoustic impacts to marine mammal habitat from pile 
driving are expected to be temporary and minimal;
    <bullet> 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, BIAs, or 
other habitats critical to recruitment or survival (e.g., rookery);
    <bullet> The project area represents a very small portion of the 
available foraging area for all potentially impacted marine mammal 
species and does not contain any habitat of particular importance;
    <bullet> Take will only occur within upper Cook Inlet--a limited, 
confined area of any given stock's home range;
    <bullet> Monitoring reports from similar work in Knik Arm have 
documented little to no observable effect on individuals of the same 
species impacted by the specified activities;
    <bullet> The required mitigation measures (i.e., soft starts, pre-
clearance monitoring, shutdown zones, bubble curtains) are expected to 
be effective in reducing the effects of the specified activity by 
minimizing the numbers of marine mammals exposed to injurious levels of 
sound and by ensuring that any take by Level A harassment is, at most, 
a small degree of AUD INJ and of a lower degree that would not impact 
the fitness of any animals; and
    <bullet> The intensity of anticipated takes by Level B harassment 
is low for all stocks consisting of, at worst, temporary modifications 
in behavior, and would not be of a duration or intensity expected to 
result in impacts on reproduction or survival.
    Cook Inlet Beluga Whales. For CIBWs, we further discuss our 
negligible impact findings in the context of potential impacts to this 
endangered stock based on our evaluation of the take proposed for 
authorization (table 25).
    As described in the Recovery Plan for the CIBW (NMFS, 2016b), 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 9 m mean lower low water and within 
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 CTR project will not impact essential 
features 1-3 listed above. All construction will be done in a manner 
implementing best management practices to preserve water quality, and 
no work will occur around creek mouths or river systems leading to prey 
abundance reductions. In addition, no physical structures will restrict 
passage; however, impacts to the acoustic habitat are relevant and 
discussed here.
    Monitoring data from the POA suggest pile driving does not 
discourage CIBWs from entering Knik Arm and traveling to critical 
foraging grounds such as those around Eagle Bay (e.g., 61N 
Environmental, 2021, 2022a, 2022b; Easley-Appleyard and Leonard, 2022). 
As described in greater detail in the Potential Effects of Specified 
Activities on Marine Mammals and Their Habitat section of this notice, 
sighting rates were not different in the presence or absence of pile 
driving (Kendall and Cornick, 2015). In addition, large numbers of 
CIBWs have continued to forage in portions of Knik Arm and pass through 
the area near the POA during pile driving projects over the past two 
decades (Funk et al., 2005; Prevel-Ramos et al., 2006; Markowitz and 
McGuire, 2007; Cornick and Saxon-Kendall, 2008, 2009; ICRC, 2009, 2010, 
2011, 2012; Cornick et al., 2010, 2011; Cornick and Pinney, 2011; 
Cornick and Seagars, 2016; POA, 2019), including during the recent PCT 
and SFD construction projects (61N Environmental, 2021, 2022a, 2022b; 
Easley-Appleyard and Leonard, 2022). These findings are not surprising 
as food is a strong motivation for marine mammals, and preying on 
seasonal anadromous fish runs in Eagle and Knik Rivers necessitates 
CIBWs passing the POA. 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 may be responding to pile 
driving noise but not through abandonment of primary foraging areas 
north of the port. Instead, they may travel faster past the POA, more 
quietly, and in smaller, tighter groups (Kendall and Cornick, 2015; 61N 
Environmental, 2021, 2022a, 2022b). CIBW presence at the POA has been 
extensively monitored during pile driving projects over the last 
several years, with data gathered during active driving activities and 
during periods of no construction noise. CIBWs are regularly observed 
at the POA even during active pile driving as discussed below.
    During PCT and SFD construction monitoring, 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 (61N Environmental, 2021, 2022a, 2022b; Easley-
Appleyard and Leonard, 2022). Of the 386 CIBWs groups sighted during

[[Page 85740]]

PCT and SFD construction monitoring, 10 groups were observed during or 
within minutes of in-water impact pile installation and 56 groups were 
observed during or within minutes of vibratory pile installation or 
removal (61N Environmental, 2021, 2022a, 2022b). In general, CIBWs were 
more likely to display no reaction or to continue to move towards the 
PCT or SFD during pile installation and removal. In the situations 
during which CIBWs showed a possible reaction (6 groups during impact 
driving and 13 groups during vibratory driving), CIBWs were observed 
either moving away immediately after the pile driving activities 
started or were observed increasing their rate of travel.
    NMFS funded a visual marine mammal monitoring project in 2021 
(described in the Potential Effects of Specified Activities on Marine 
Mammals and Their Habitat) to supplement sighting data collected by the 
POA monitoring program during non-pile driving days in order to further 
evaluate the impacts of anthropogenic activities on CIBWs (Easley-
Appleyard and Leonard, 2022). Preliminary results suggest that group 
size ranged from 1 to 34 whales, with an average of 3 to 5.6, depending 
on the month. September had the highest sighting rate with 4.08 whales 
per hour, followed by October and August (3.46 and 3.41, respectively). 
Traveling was recorded as the primary behavior for 80 percent of the 
group sightings and milling was the secondary behavior most often 
recorded. Sighting duration varied from a single surfacing lasting less 
than 1 minute to 380 minutes. Preliminary findings suggest these 
results are consistent with the results from the POA's PCT and SFD 
monitoring efforts. For example, group sizes ranged from 2.38 to 4.32 
depending on the month and the highest sighting rate was observed in 
September (1.75). In addition, traveling was the predominant behavior 
observed for all months and categories of construction activity (i.e., 
no pile driving, before pile driving, during pile driving, between pile 
driving, or after pile driving), being recorded as the primary behavior 
for 86 percent of all sightings, and either the primary or secondary 
behavior for 95 percent of sightings.
    Easley-Appleyard and Leonard (2022) also asked PSOs to complete a 
questionnaire post-monitoring that provided NMFS with qualitative data 
regarding CIBW behavior during observations. Specifically during pile 
driving events, the PSOs noted that CIBW behaviors varied; however, 
multiple PSOs noted seeing behavioral changes specifically during 
impact pile driving and not during vibratory pile driving. CIBWs were 
observed sometimes changing direction, turning around, or changing 
speed during impact pile driving, whereas there were numerous instances 
where CIBWs were seen traveling directly towards the POA during 
vibratory pile driving before entering the Level B harassment zone (61N 
Environmental, 2021, 2022a, 2022b). The PSOs also reported that it 
seemed more likely for CIBWs to show more cryptic behavior during 
active impact and vibratory pile driving (e.g., surfacing infrequently 
and without clear direction), though this seemed to vary across months 
(Easley-Appleyard and Leonard, 2022).
    We anticipate that disturbance to CIBWs will manifest in the same 
manner when they are exposed to noise during the CTR project: whales 
would move quickly and silently through the area in more cohesive 
groups. Exposure to elevated noise levels during transit past the POA 
is not expected to have adverse effects on reproduction or survival as 
the whales continue to access critical foraging grounds north of the 
POA. Potential behavioral reactions that have been observed, including 
changes in group distribution and speed, may help to mitigate the 
potential for any contraction of communication space for a group. CIBWs 
are not expected to abandon entering or exiting Knik Arm as this is not 
evident based on monitoring data from the past two decades of work at 
POA (e.g., Funk et al., 2005; Prevel-Ramos et al., 2006; Markowitz and 
McGuire, 2007; Cornick and Saxon-Kendall, 2008, 2009; ICRC, 2009, 2010, 
2011, 2012; Cornick et al., 2010, 2011; Cornick and Pinney, 2011; 
Cornick and Seagars, 2016; POA, 2019; Kendall and Cornick, 2015; 61N 
Environmental, 2021, 2022a, 2022b; Easley-Appleyard and Leonard, 2022). 
Finally, as described previously, both telemetry (tagging) and acoustic 
data suggest CIBWs likely stay in upper Knik Arm (i.e., north of the 
CTR project site) 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 18, 1999 and remained in Eagle Bay 
until September 12, 1999 (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 will avoid repetitive exposures from pile driving noise.
    It is possible 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 
thus, impacting essential feature number five of the designated 
Critical Habitat. The data previously presented demonstrate CIBWs are 
not abandoning the area (i.e., continue to access the waters of 
northern Knik Arm during construction activities). Additionally, 
results of an 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 
(2016b) 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 EE, the experts 
provided a set of parameters and values that determined the forms of a 
relationship between the number of ``days of disturbance'' (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)) a female CIBW experiences in a particular period and the 
effect of that disturbance on her energy reserves. Examples included 
the number of disturbed days during the months of 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 disturbed days of from 
April to September required to reduce the energy reserves of a 
lactating CIBW to a level where she is certain to abandon her calf; and 
the threshold

[[Page 85741]]

disturbed days 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, a ``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 to be comprised predominantly of temporary modifications in 
the behavior of individual CIBWs (e.g., faster swim speeds, more 
cohesive group structure, decreased sighting durations, cessation of 
vocalizations) based on the large body of observational data available 
from previous monitoring efforts at the Port. Also, NMFS proposes to 
authorize an annual maximum of 90 instances of takes, with the 
instances representing disturbance events within a day. This means that 
either 90 different individual CIBWs are disturbed on no more than 1 
day each per year or some lesser number of individuals may be disturbed 
on more than 1 day but with the product of individuals and days not 
exceeding 90. Given the overall estimated take, it is unlikely that any 
one CIBW will be disturbed on more than a few days. Further, the 
mitigation measures NMFS has proposed for the CTR project are designed 
to avoid the potential that any animal will lose the ability to forage 
for one or more tidal cycles should they be foraging in the proposed 
action area, which is not known to be a particularly important feeding 
area for CIBWs.
    While Level B harassment (behavioral disturbance) is proposed to be 
authorized, the POA's mitigation measures will 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. Given 
that individuals in potentially vulnerable life stages, such as 
pregnancy, cannot be identified by visual observers, pile driving would 
be shut down for all CIBWs to be protective of potentially vulnerable 
individuals, and to avoid more severe behavioral reactions.
    NMFS proposes required mitigation measures to minimize exposure to 
CIBWs, specifically, shutting down pile driving should a CIBW approach 
or enter the Level B harassment zone. These measures are designed to 
reduce the intensity and duration of potential harassment CIBWs 
experience during the POA's construction activities. Additionally, the 
proposed mitigation measures would help to ensure CIBWs will not 
experience degradation of acoustic habitat approaching the threshold 
set in the Critical Habitat designation (i.e., in-water noise at levels 
resulting in the abandonment of habitat by CIBWs). The location of the 
PSOs would allow for detection of CIBWs and behavioral observations 
prior to CIBWs entering the Level B harassment zone.
    Additionally, NMFS proposes to require use of a bubble curtain for 
all permanent piles in waters deeper than 3 m in all months and for all 
piles (permanent or temporary) installed or extracted in waters deeper 
than 3 m during the months of August-October when CIBWs are present in 
higher numbers in Knik Arm. This measure is designed to reduce the 
amount of noise exposure at frequencies to which CIBWs are more 
sensitive (<100 Hz) during vibratory pile driving and to reduce overall 
sound levels during impact driving. During impact driving, the POA must 
implement soft starts, which ideally allows animals to leave a 
disturbed area before the full-power driving commences (Tougaard et 
al., 2012). Although NMFS does not anticipate CIBWs will abandon 
entering Knik Arm in the presence of pile driving, 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 proposed to be authorized.
    In summary, 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:
    <bullet> No mortality, serious injury, or Level A harassment is 
anticipated or proposed to be authorized;
    <bullet> Any acoustic impacts to marine mammal habitat from pile 
driving are expected to be temporary and minimal;
    <bullet> The required mitigation measures (i.e., soft starts, pre-
clearance monitoring, shutdown zones, bubble curtains) are expected to 
be effective in reducing the effects of the specified activity by 
ensuring that no CIBWs are exposed to noise at injurious levels (i.e., 
Level A harassment);
    <bullet> The intensity of anticipated takes by Level B harassment 
is low, consisting of, at worst, temporary modifications in behavior, 
and would not be of a duration or intensity expected to result in 
impacts on reproduction or survival.
    <bullet> The area of exposure would be limited to habitat primarily 
used as a travel corridor. Data demonstrates Level B harassment of 
CIBWs typically manifests as increased swim speeds past the POA, 
tighter group formations, and cessation of vocalizations, rather than 
through habitat abandonment;
    <bullet> No critical foraging grounds (e.g., Eagle Bay, Eagle 
River, Susitna Delta) would be affected by pile driving; and
    <bullet> 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 potential severity and interaction between harassment 
events for affected individuals.
    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 required monitoring and 
mitigation measures, NMFS preliminarily finds that the proposed marine 
mammal take from the specified activity will have a negligible impact 
on all affected marine mammal species or stocks.

Small Numbers

    As noted previously, only incidental take of small numbers of 
marine mammals 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 maximum 
estimated number of individuals annually 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 maximum annual 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, except for the Mexico-North Pacific stock of 
humpback whales whose abundance estimate is unknown, the proposed 
number of takes is less than one-third of the best available population 
abundance estimate (i.e., less than 1 percent for 6 stocks; less than 2 
percent for 1 stock; and less than 27.2 percent for CIBWs; see table 
25). The maximum annual number of animals proposed for authorization to 
be

[[Page 85742]]

taken from these stocks would be considered small relative to the 
relevant stock's abundances even if each estimated take occurred to a 
new individual. The number of takes authorized likely represents 
smaller numbers of individual harbor seals and Steller sea lions. 
Harbor seals tend to concentrate near Ship Creek and have small home 
ranges. It is possible that a single individual harbor seal may linger 
near the POA, especially near Ship Creek and be counted multiple times 
each day as it moves around and resurfaces in different locations. 
Previous Steller sea lion sightings identified that if a Steller sea 
lion is within Knik Arm, it is likely lingering to forage on salmon or 
eulachon runs and may be present for several days. Therefore, the 
number of takes authorized likely represents repeat exposures to the 
same animals in certain circumstances. For all species, PSOs would 
count individuals as separate unless they can be individually 
identified.
    Abundance estimates for the Mexico-North Pacific stock of humpback 
whales are based upon data collected more than 8 years ago, and 
therefore, current estimates are considered unknown (Young et al., 
2023). The most recent minimum population estimates (N<INF>MIN</INF>) 
for this population include an estimate of 2,241 individuals between 
2003 and 2006 (Martinez-Aguilar, 2011) and 766 individuals between 2004 
and 2006 (Wade, 2021). NMFS' Guidelines for Assessing Marine Mammal 
Stocks suggest that the N<INF>MIN</INF> estimate of the stock should be 
adjusted to account for potential abundance changes that may have 
occurred since the last survey and provide reasonable assurance that 
the stock size is at least as large as the estimate (NMFS, 2023). The 
abundance trend for this stock is unclear; therefore, there is no basis 
for adjusting these estimates (Young et al., 2023). Assuming the 
population has been stable, the maximum annual 4 takes of this stock 
proposed for authorization represents small numbers of this stock (0.18 
percent of the stock assuming a N<INF>MIN</INF> of 2,241 individuals 
and 0.52 percent of the stock assuming an N<INF>MIN</INF> of 766 
individuals).
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
estimated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals would be taken relative to the population 
size of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to promulgate regulations, NMFS must find that the takings 
authorized will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    While no significant subsistence activity currently occurs within 
or near the POA, Alaska Natives have traditionally harvested 
subsistence resources, including marine mammals, in upper Cook Inlet 
for millennia. CIBWs are more than a food source; they are important to 
the cultural and spiritual practices of Cook Inlet Native communities 
(NMFS, 2008b). Dena'ina Athabascans, currently living in the 
communities of Eklutna, Knik, Tyonek, and elsewhere, occupied 
settlements in Cook Inlet for the last 1,500 years and have been the 
primary traditional users of this area into the present.
    NMFS estimated that 65 CIBWs per year (range 21-123) were killed 
between 1994 and 1998, including those successfully harvested and those 
struck and lost. NMFS concluded that this number was high enough to 
account for the estimated 14 percent annual decline in population 
during this time (Hobbs et al., 2008); however, given the difficulty of 
estimating the number of whales struck and lost during the hunts, 
actual mortality may have been higher. During this same period, 
population abundance surveys indicated a population decline of 47 
percent, although the reason for this decline should not be associated 
solely with subsistence hunting and likely began well before 1994 (Rugh 
et al., 2000).
    In 1999, a moratorium was enacted (Pub. L. 106-31) prohibiting the 
subsistence harvest of CIBWs except through a cooperative agreement 
between NMFS and the affected Alaska Native organizations. NMFS began 
working cooperatively with the Cook Inlet Marine Mammal Council 
(CIMMC), a group of tribes that traditionally hunted CIBWs, to 
establish sustainable harvests. CIMMC voluntarily curtailed its 
harvests in 1999. In 2000, NMFS designated the Cook Inlet stock of 
beluga whales as depleted under the MMPA (65 FR 34590, May 31, 2000). 
NMFS and CIMMC signed Co-Management of the Cook Inlet Stock of Beluga 
Whales agreements in 2000, 2001, 2002, 2003, 2005, and 2006. CIBW 
harvests between 1999 and 2006 resulted in the strike and harvest of 
five whales, including one whale each in 2001, 2002, and 2003, and two 
whales in 2005 (NMFS, 2008b). No hunt occurred in 2004 due to higher-
than-normal mortality of CIBWs in 2003, and the Native Village of 
Tyonek agreed to not hunt in 2007. Since 2008, NMFS has examined how 
many CIBWs could be harvested during 5-year intervals based on 
estimates of population size and growth rate and determined that no 
harvests would occur between 2008 and 2012 and between 2013 and 2017 
(NMFS, 2008b). The CIMMC was disbanded by unanimous vote of the CIMMC 
member Tribes' representatives in June 2012, and a replacement group of 
Tribal members has not been formed to date. There has been no 
subsistence harvest of CIBWs since 2005 (NMFS, 2022d).
    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. Residents of the Native Village of Tyonek are the primary 
subsistence users in the upper Cook Inlet area. While harbor seals are 
hunted for subsistence purposes, harvests of this species for 
traditional and subsistence uses by Native peoples have been low in 
upper Cook Inlet (e.g., 33 harbor seals were harvested in Tyonek 
between 1983 and 2013; see table 8-1 in the POA's application), 
although these data are not currently being collected and summarized. 
As the POA's proposed project activities will take place within the 
immediate vicinity of the POA, no activities will occur in or near 
Tyonek's identified traditional subsistence hunting areas. As the 
harvest of marine mammals in upper Cook Inlet is historically a small 
portion of the total subsistence harvest and the number of marine 
mammals using upper Cook Inlet is proportionately small, the number of 
marine mammals harvested in upper Cook Inlet is expected to remain low.
    The potential impacts from harassment on stocks that are harvested 
in Cook Inlet would be limited to minor

[[Page 85743]]

behavioral changes (e.g., increased swim speeds, changes in dive time, 
temporary avoidance near the POA) 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, pre-
clearance monitoring, bubble curtains, soft starts) 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.
    The POA will communicate with representative Alaska Native 
subsistence users and Tribal members to identify and explain the 
measures that have been taken or will be taken to minimize any adverse 
effects of CTR on the availability of marine mammals for subsistence 
uses. In addition, the POA will adhere to the following communication 
procedures regarding marine mammal subsistence use within the Project 
area:
    (1) Send letters to the Kenaitze, Tyonek, Knik, Eklutna, Ninilchik, 
Salamatof, and Chickaloon Tribes informing them of the proposed project 
(i.e., timing, location, and features). Include a map of the proposed 
project area; identify potential impacts to marine mammals and 
mitigation efforts, if needed, to avoid or minimize impacts; and 
inquire about possible marine mammal subsistence concerns they have.
    (2) Follow up with a phone call to the environmental departments of 
the seven Tribal entities to ensure that they received the letter, 
understand the proposed project, and have a chance to ask questions. 
Inquire about any concerns they might have about potential impacts to 
subsistence hunting of marine mammals.
    (3) Document all communication between the POA and Tribes.
    (4) If any Tribes express concerns regarding proposed project 
impacts to subsistence hunting of marine mammals, propose a Plan of 
Cooperation between the POA and the concerned Tribe(s).
    The proposed project features and activities, in combination with a 
number of actions to be taken by the POA during project implementation, 
should avoid or mitigate any potential adverse effects on the 
availability of marine mammals for subsistence uses. Furthermore, 
although construction will occur within the traditional area for 
hunting marine mammals, the proposed project area is not currently used 
for subsistence activities. In-water pile installation and removal will 
follow mitigation procedures to minimize effects on the behavior of 
marine mammals and impacts will be temporary.
    For the NES1 project, the POA expressed that, if desired, regional 
subsistence representatives may support project marine mammal 
biologists during the monitoring program by assisting with collection 
of marine mammal observations and may request copies of marine mammal 
monitoring reports. The POA proposes the same option for the CTR 
project.
    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 promulgation of 
regulations, NMFS consults internally whenever we propose to authorize 
take for endangered or threatened species, in this case with the NMFS 
Alaska Regional Office.
    NMFS Office of Protected Resources (OPR) is proposing to authorize 
take of Mexico-North Pacific humpback whales (including individuals 
from the Mexico DPS), CIBWs, and western DPS Steller sea lions, which 
are listed under the ESA. NMFS OPR has requested initiation of section 
7 consultation on the promulgation of regulations and issuance of a 
subsequent LOA. NMFS will conclude the ESA consultation prior to 
reaching a determination regarding the proposed issuance of the 
authorization.

Proposed Promulgation

    As a result of these preliminary determinations, NMFS proposes to 
promulgate regulations that allow for the authorization of take, by 
Level A harassment and Level B harassment, incidental to construction 
activities associated with the Cargo Terminals Replacement Project at 
the Don Young Port of Alaska in Anchorage, Alaska for a 5-year period 
from March 1, 2026, through February 28, 2031, provided the previously 
mentioned mitigation, monitoring, and reporting requirements are 
incorporated.

Request for Information

    NMFS requests interested persons to submit comments, information, 
and suggestions concerning the POA's request and the proposed 
regulations (see ADDRESSES). All comments will be reviewed and 
evaluated as we prepare a final rule and make final determinations on 
whether to issue the requested authorization. This proposed rule and 
referenced documents provide all environmental information relating to 
our proposed action for public review.

Classification

    The Office of Management and Budget has determined that this 
proposed rule is not significant for purposes of Executive Order 12866.
    Pursuant to section 605(b) of the Regulatory Flexibility Act (RFA) 
(5 U.S.C. 601 et seq.), the Chief Counsel for Regulation of the 
Department of Commerce has certified to the Chief Counsel for Advocacy 
of the Small Business Administration that this proposed rule, if 
adopted, would not have a significant economic impact on a substantial 
number of small entities. The POA is an enterprise activity of the 
Municipality of Anchorage, Alaska, meaning that it is a department of 
the Municipality which generates adequate revenue to support its 
operational costs and annual payments to the Municipality. The POA is 
the sole entity that would be subject to the requirements in these 
proposed regulations, and the POA is not a small governmental 
jurisdiction, small organization, or small business, as defined by the 
RFA, because it is a department of the local government. Because of 
this certification, a regulatory flexibility analysis is not required 
and none has been prepared.
    This proposed rule contains a collection-of-information requirement 
subject to the provisions of the Paperwork Reduction Act (PRA). 
Notwithstanding any other provision of law, no person is required to 
respond to nor shall a person be subject to a penalty for failure to 
comply with a collection of information subject to the requirements of 
the PRA unless that collection of information displays a currently 
valid OMB control number. These requirements have been approved by OMB 
under control number 0648-

[[Page 85744]]

0151 and include applications for regulations, subsequent LOAs, and 
reports.

List of Subjects in 50 CFR Part 217

    Acoustics, Administrative practice and procedure, Construction, 
Endangered and threatened species, Marine mammals, Mitigation and 
monitoring requirements, Reporting requirements, Wildlife.

    Dated: October 18, 2024.
Samuel D. Rauch III,
Deputy Assistant Administrator for Regulatory Programs, National Marine 
Fisheries Service.

    For reasons set forth in the preamble, NMFS proposes to amend 50 
CFR part 217 to read as follows:

PART 217--REGULATIONS GOVERNING THE TAKING AND IMPORTING OF MARINE 
MAMMALS

0
1. The authority citation for part 217 continues to read as follows:

    Authority:  16 U.S.C. 1361 et seq.

0
2. Add subpart B, consisting of Sec. Sec.  217.11 through 217.19, to 
read as follows:
Subpart B--Taking Marine Mammals Incidental to the Port of Alaska 
Modernization Program Phase 2B: Cargo Terminals Replacement Project in 
Anchorage, Alaska
Sec.
217.11 Specified activity and specified geographical region.
217.12 Effective dates.
217.13 Permissible methods of taking.
217.14 Prohibitions.
217.15 Mitigation requirements.
217.16 Requirements for monitoring and reporting.
217.17 Letters of Authorization.
217.18 Modifications of Letters of Authorization.
217.19 [Reserved]

Subpart B--Taking Marine Mammals Incidental to the Port of Alaska 
Modernization Program Phase 2B: Cargo Terminals Replacement Project 
in Anchorage, Alaska


Sec.  217.11  Specified activity and specified geographical region.

    (a) The incidental taking of marine mammals by the Port of Alaska 
(POA) may be authorized in a Letter of Authorization (LOA) only if it 
occurs at or around the Port of Alaska, including waters of Knik Arm 
and Upper Cook Inlet near Anchorage, Alaska incidental to the specified 
activities outlined in paragraph (b) of this section.
    (b) The specified activities are construction and demolition 
activities associated with the Cargo Terminals Replacement Project 
under the Port of Alaska Modernization Program at the Don Young Port of 
Alaska in Anchorage, Alaska.


Sec.  217.12  Effective dates.

    Regulations in this subpart are effective from March 1, 2026, until 
February 28, 2031.


Sec.  217.13  Permissible methods of taking.

    Under a LOA issued pursuant to Sec.  216.106 of this chapter and 
Sec.  217.17, the POA and those persons it authorizes or funds to 
conduct activities on its behalf may incidentally, but not 
intentionally, take marine mammals within the specified geographical 
region by harassment associated with the specified activities provided 
they are in compliance with all terms, conditions, and requirements of 
the regulations in this subpart and the applicable LOA.


Sec.  217.14  Prohibitions.

    (a) Except for the takings permitted in Sec.  217.13 and authorized 
by a LOA issued under Sec.  216.106 of this chapter and Sec.  217.17, 
it is unlawful for any person to do any of the following in connection 
with the specified activities:
    (1) Violate or fail to comply with the terms, conditions, and 
requirements of this subpart or a LOA issued under this subpart;
    (2) Take any marine mammal not specified in such LOA;
    (3) Take any marine mammal specified in such LOA in any manner 
other than specified;
    (4) Take a marine mammal specified in such LOA if NMFS determines 
such taking results in more than a negligible impact on the species or 
stocks of such marine mammal; or
    (5) Take a marine mammal specified in such LOA after NMFS 
determines such taking results in an unmitigable adverse impact on the 
species or stock of such marine mammal for taking for subsistence uses.
    (b) [Reserved]


Sec.  217.15  Mitigation requirements.

    (a) When conducting the specified activities identified in Sec.  
217.11(b), POA must implement the mitigation measures contained in this 
section and any LOA issued under Sec. Sec.  216.106 of this chapter and 
217.17. These mitigation measures include, but are not limited to:
    (1) A copy of any issued LOA must be in the possession of the POA, 
its designees, and work crew personnel operating under the authority of 
the issued LOA.
    (2) The POA must ensure that construction supervisors and crews, 
the monitoring team and relevant POA staff are trained prior to the 
start of all pile driving so that responsibilities, communication 
procedures, monitoring protocols, and operational procedures are 
clearly understood. New personnel joining during the project must be 
trained prior to commencing work.
    (3) The POA must employ Protected Species Observers (PSOs) and 
establish monitoring locations pursuant to Sec.  217.16 and as 
described in a NMFS-approved Marine Mammal Monitoring and Mitigation 
Plan.
    (i) For all pile driving activities, land-based PSOs must be 
stationed at the best vantage points practicable to monitor for marine 
mammals and implement shutdown/delay procedures. A minimum of 4 
locations must be used to monitor the designated harassment zones to 
the maximum extent possible based on daily visibility conditions. 
Additional PSOs must be added if warranted by site conditions and/or 
the level of marine mammal activity in the area. PSOs must be able 
implement shutdown or delay procedures when applicable through 
communication with the equipment operator.
    (ii) If during pile driving activities, PSOs can no longer 
effectively monitor the entirety of the Cook Inlet beluga whale (CIBW) 
shutdown zone due to environmental conditions (e.g., fog, rain, wind), 
pile driving may continue only until the current segment of the pile is 
driven; no additional sections of pile or additional piles may be 
driven until conditions improve such that the shutdown zone can be 
effectively monitored. If the shutdown zone cannot be monitored for 
more than 15 minutes, the entire zone must be cleared again for 30 
minutes prior to reinitiating pile driving.
    (4) Pre-start Clearance Monitoring must take place from 30 minutes 
prior to initiation of pile driving activity (i.e., pre-start clearance 
monitoring) through 30 minutes post-completion of pile driving 
activity.
    (i) Pre-start clearance monitoring must be conducted during periods 
of visibility sufficient for the Lead PSO to determine that the 
shutdown zones are clear of marine mammals.
    (ii) Pile driving may commence if, following 30 minutes of 
observation, it is determined by the Lead PSO that the shutdown zones 
are clear of marine mammals and for CIBW, any observed whale(s) is at 
least 100 meters past the shutdown zone and on a path away from the 
zone or the whale has not been re-sighted for 30 minutes.
    (5) For all pile driving activity, the POA must implement shutdown 
zones with radial distances as identified in a

[[Page 85745]]

LOA issued under Sec.  216.106 of this chapter and Sec.  217.17.
    (i) If a marine mammal is observed entering or within the shutdown 
zone, all pile driving activities, including soft starts, at that 
location must be halted. If pile driving is halted or delayed due to 
the presence of a marine mammal, the activity may not commence or 
resume until either the animal has voluntarily left and is been 
visually confirmed beyond the shutdown zone or 15 minutes (non-CIBWs) 
or 30 minutes (CIBWs) have passed without re-detection of the animal. 
Specific to CIBW, if a CIBW(s) is observed within or on a path towards 
the shutdown zone, pile driving activities, including soft starts, must 
shut down and not re-commence until the whale has traveled at least 100 
m beyond the shutdown zone and is on a path away from such zone or 
until no CIBW has been observed in the shutdown zone for 30 minutes.
    (ii) In the event of a delay or shutdown of activity resulting from 
marine mammals in the shutdown zone, animal behavior must be monitored 
and documented.
    (iii) If work ceases for more than 30 minutes, the shutdown zones 
must be cleared again for 30 minutes prior to reinitiating pile 
driving. A determination that the shutdown zone is clear must be made 
during a period of good visibility.
    (iv) If a shutdown procedure should be initiated but human safety 
is at risk, as determined by the best professional judgment of the 
vessel operator or project engineer, the in-water activity, including 
pile driving, is allowed to continue until the risk to human safety has 
dissipated. In this scenario, pile driving may continue only until the 
current segment of the pile is driven; no additional sections of pile 
or additional piles may be driven until the Lead PSO has determined 
that the shutdown zones are clear of marine mammals and for Cook Inlet 
beluga whales (CIBW), any observed whale(s) is at least 100 meters past 
the shutdown zone and on a path away from the zone.
    (v) For in-water construction activities other than pile driving 
(e.g., barge positioning; use of barge-mounted excavators; dredging), 
if a marine mammal comes within 10 m, POA must cease operations and 
reduce vessel speed to the minimum level required to maintain steerage 
and safe working conditions. If human safety is at risk, as determined 
by the best professional judgment of the vessel operator or project 
engineer, the in-water activity is allowed to continue until the risk 
to human safety has dissipated.
    (6) The POA must use soft start techniques when impact pile 
driving. Soft start requires contractors to conduct three sets of 
strikes (three strikes per set) at reduced hammer energy with a 30-
second waiting period between each set. 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 30 
minutes or longer.
    (7) The POA must use bubble curtains for all temporary (36- or 24-
in diameter) piles during both vibratory and impact pile driving in 
water depths greater than 3 meters (9.8 ft) between August 1 and 
October 31. Bubble curtains must be used for all permanent piles (72-in 
diameter) during both vibratory and impact pile driving in waters 
deeper than 3 meters (9.8 feet). The bubble curtain must be operated to 
achieve optimal performance. At a minimum, the bubble curtain must:
    (i) The bubble curtain must distribute air bubbles around 100 
percent of the piling perimeter for the full depth of the water column.
    (ii) The lowest bubble ring must be in contact with the mudline 
and/or rock bottom for the full circumference of the ring, and the 
weights attached to the bottom ring shall ensure 100 percent mudline 
and/or rock bottom contact. No parts of the ring or other objects shall 
prevent full mudline and/or rock bottom contact.
    (iii) Air flow to the bubblers must be balanced around the 
circumference of the pile.
    (8) Pile driving activity must be halted upon observation of a 
species entering or within the harassment zone for either a species for 
which incidental take is not authorized or a species for which 
incidental take has been authorized but the authorized number of takes 
has been met.
    (b) [Reserved]


Sec.  217.16  Requirements for monitoring and reporting.

    (a) The POA must submit a Marine Mammal Monitoring and Mitigation 
Plan to NMFS for approval at least 90 days before the start of 
construction and abide by the Plan, if approved.
    (b) Monitoring must be conducted by qualified, NMFS-approved PSOs, 
in accordance with the following conditions:
    (1) PSOs must be independent of the activity contractor (e.g., 
employed by a subcontractor) and have no other assigned tasks during 
monitoring duties.
    (2) PSOs must be approved by NMFS prior to beginning work on the 
specified activities.
    (3) PSOs must be trained in marine mammal identification and 
behavior.
    (i) A designated Project Lead PSO must always be on site. The 
Project Lead PSO must have prior experience performing the duties of a 
PSO during in-water construction activities pursuant to a NMFS-issued 
ITA or Letter of Concurrence.
    (ii) Each PSO station must also have a designated Station Lead PSO 
specific to that station and shift. These Station Lead PSOs must have 
prior experience working as a PSO during in-water construction 
activities;
    (iii) Other PSOs may substitute other relevant experience 
(including relevant Alaska Native traditional knowledge), education 
(degree in biological science or related field), or training for prior 
experience performing the duties of a PSO during construction activity 
pursuant to a NMFS-issued incidental take authorization.
    (4) PSO stations must be elevated platforms constructed on top of 
shipping containers or a similar base that is at least 8'6'' high 
(i.e., the standard height of a shipping container) that can support at 
least three PSOs and their equipment. The platforms must be stable 
enough to support use of a theodolite and must be located to optimize 
the PSO's ability to observe marine mammals and the shutdown zones. 
Each PSO station must have at least two PSOs on watch at any given 
time, including the Station Lead PSO.
    (5) If the POA is conducting in-water work for other projects that 
includes PSOs, the PSOs for the Cargo Terminals Replacement Project 
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.
    (c) The POA must submit weekly monitoring reports within 14 days 
after the conclusion of each calendar week during each Cargo Terminals 
Replacement Project construction season. These reports must include a 
summary of marine mammal species and behavioral observations, 
construction shutdowns or delays, and construction work completed 
during the reporting period. The weekly reports also must include an 
assessment of the amount of construction remaining to be completed 
(i.e., the number of estimated hours of work remaining), in addition to 
the number of beluga whales observed within estimated harassment zones 
to date.
    (d) The POA must submit a draft annual summary monitoring report on 
all monitoring conducted during each construction season which includes 
final electronic data sheets within 90

[[Page 85746]]

calendar days after the completion of each construction season or 60 
days prior to a requested date of issuance of any future incidental 
take authorization for projects at the same location, whichever comes 
first. A draft comprehensive 5-year summary report must also be 
submitted to NMFS within 90 days of the end of year 5 of the project. 
The reports must detail the monitoring protocol and summarize the data 
recorded during monitoring. If no comments are received from NMFS 
within 30 days of receipt of the draft report, the report may be 
considered final. If comments are received, a final report addressing 
NMFS comments must be submitted within 30 days after receipt of 
comments. At a minimum, the reports must contain:
    (1) Dates and times (begin and end) of all marine mammal 
monitoring;
    (2) Construction activities occurring during each daily observation 
period, including how many and what type of piles were driven or 
removed, by what method (i.e., impact or vibratory), the total duration 
of driving time for each pile (vibratory driving), and number of 
strikes for each pile (impact driving);
    (3) Environmental conditions during monitoring periods (at 
beginning and end of PSO shift and whenever conditions change 
significantly), Beaufort sea state, and any other relevant weather 
conditions including cloud cover, fog, sun glare, and overall 
visibility to the horizon, and estimated observable distance (if less 
than the harassment zone distance);
    (4) Upon observation of a marine mammal, the following information 
should be collected:
    (i) Name of the PSO who sighted the animal, observer location, and 
activity at time of sighting:
    (ii) Time of sighting;
    (iii) Identification of the animal (e.g., genus/species, lowest 
possible taxonomic level, or unidentified), PSO confidence in 
identification, and the composition of the group if there is a mix of 
species;
    (iv) Distances and bearings of each marine mammal observed in 
relation to the pile being driven for each sighting (if pile driving 
was occurring at time of sighting);
    (v) Estimated number of animals (min/max/best);
    (vi) Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition, etc.);
    (vii) Animal's closest point of approach and estimated time spent 
within the harassment zone;
    (viii) Description of any marine mammal behavioral observations 
(e.g., observed behaviors such as feeding or traveling), including an 
assessment of behavioral responses to the activity (e.g., no response 
or changes in behavioral state such as ceasing feeding, changing 
direction, flushing, or breaching);
    (ix) Detailed information about any implementation of any 
mitigation (e.g., shutdowns and delays), a description of specific 
actions that ensued, and resulting changes in the behavior of the 
animal, if any; and
    (x) All PSO datasheets and raw sightings data in electronic 
spreadsheet format.
    (e) In the event that personnel involved in the construction 
activities discover an injured or dead marine mammal, the POA must 
report the incident to NMFS Office of Protected Resources (OPR) and to 
the Alaska Regional Stranding Coordinator no later than 24 hours after 
the initial observation. If the death or injury was caused by the 
specified activity, the POA must immediately cease the specified 
activities until NMFS OPR is able to review the circumstances of the 
incident. The POA must not resume their activities until notified by 
NMFS. The report must include the following information:
    (1) Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    (2) Species identification (if known) or description of the 
animal(s) involved;
    (3) Condition of the animal(s) (including carcass condition if the 
animal is dead);
    (4) Observed behaviors of the animal(s), if alive;
    (5) If available, photographs or video footage of the animal(s); 
and
    (6) General circumstances under which the animal was discovered.


Sec.  217.17  Letters of Authorization.

    (a) To incidentally take marine mammals pursuant to these 
regulations, the POA must apply for and obtain an LOA.
    (b) An LOA, unless suspended or revoked, may be effective for a 
period of time not to exceed the effective dates of this subpart.
    (c) If an LOA expires prior to the end of the effective dates of 
this subpart, the POA may apply for and obtain a renewal of the LOA.
    (d) In the event of projected changes to the activity or to 
mitigation and monitoring measures required by an LOA, the POA must 
apply for and obtain a modification of the LOA as described in Sec.  
217.18.
    (e) The LOA must set forth the following information:
    (1) Permissible methods of incidental taking;
    (2) Means of effecting the least practicable adverse impact (i.e., 
mitigation) on the species, its habitat, and on the availability of the 
species for subsistence uses; and
    (3) Requirements for monitoring and reporting.
    (f) Issuance of the LOA must be based on a determination that the 
level of taking will be consistent with the findings made for the total 
taking allowable under this subpart.
    (g) Notice of issuance or denial of an LOA must be published in the 
Federal Register within 30 days of a determination.


Sec.  217.18  Modifications of Letters of Authorization.

    (a) A LOA issued under Sec. Sec.  216.106 of this chapter and 
217.17 for the specified activities may be modified upon request by the 
POA, provided that:
    (1) The specified activity and mitigation, monitoring, and 
reporting measures, as well as the anticipated impacts, are the same as 
those described and analyzed for this subpart; and
    (2) NMFS determines that the mitigation, monitoring, and reporting 
measures required by the previous LOA were implemented.
    (b) For LOA modification by the POA that includes changes to the 
specified activity or the mitigation, monitoring, or reporting measures 
that do not change the findings made for the regulations in this 
subpart or result in no more than a minor change in the total estimated 
number of takes (or distribution by species or years), NMFS may publish 
a notice of proposed LOA in the Federal Register, including the 
associated analysis of the change and solicit public comment before 
issuing the LOA.
    (c) A LOA issued under Sec.  216.106 of this chapter and Sec.  
217.17 for the specified activity may be modified by NMFS under the 
following circumstances:
    (1) NMFS may modify the existing mitigation, monitoring, or 
reporting measures, after consulting with the POA regarding the 
practicability of the modifications, if doing so creates a reasonable 
likelihood of more effectively accomplishing the goals of the 
mitigation and monitoring measures;
    (i) Possible sources of data that could contribute to the decision 
to modify the mitigation, monitoring, or reporting measures in an LOA 
include, but are not limited to:
    (A) Results from the POA's monitoring;
    (B) Results from other marine mammal and/or sound research or 
studies; and
    (C) Any information that reveals marine mammals may have been taken

[[Page 85747]]

in a manner, extent or number not authorized by this subpart or 
subsequent LOAs; and
    (ii) If, through adaptive management, the modifications to the 
mitigation, monitoring, or reporting measures are substantial, NMFS 
shall publish a notice of proposed LOA in the Federal Register and 
solicit public comment;
    (2) If NMFS determines that an emergency exists that poses a 
significant risk to the well-being of the species or stocks of marine 
mammals specified in a LOA issued pursuant to Sec.  216.106 of this 
chapter and Sec.  217.17, a LOA may be modified without prior notice or 
opportunity for public comment. Notification will be published in the 
Federal Register within 30 days of the action.


Sec.  217.19  [Reserved]

[FR Doc. 2024-24580 Filed 10-25-24; 8:45 am]
BILLING CODE 3510-22-P


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