[Federal Register Volume 86, Number 149 (Friday, August 6, 2021)]
[Notices]
[Pages 43190-43204]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-16861]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RTID 0648-XB234]


Taking of Marine Mammals Incidental to Specific Activities; 
Taking of Marine Mammals Incidental to Pile Driving and Removal 
Activities During the Metlakatla Seaplane Facility Refurbishment 
Project, Metlakatla, Alaska

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

ACTION: Notice; issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an incidental harassment authorization (IHA) to 
the Alaska Department of Transportation and Public Facilities 
(AKDOT&PF) to incidentally harass, by Level B harassment only, marine 
mammals during pile driving/removal and down-the-hole drilling (DTH) 
activities for maintenance improvements to the existing Metlakatla 
Seaplane Facility (MSF) in Southeast Alaska.

DATES: This Authorization is effective for one year from issuance.

FOR FURTHER INFORMATION CONTACT: Stephanie Egger, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online at: https://www.fisheries.noaa.gov/action/incidental-take-authorization-alaska-department-transportation-metlakatla-seaplane-facility. In case of 
problems accessing these documents, or for anyone who is unable to 
comment via electronic mail, please call the contact listed above.

SUPPLEMENTARY INFORMATION:

Background

    The MMPA prohibits the ``take'' of marine mammals, with certain 
exceptions. Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 
et

[[Page 43191]]

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

Summary of Request

    On August 10, 2020, NMFS received a request from the AKDOT&PF for 
an IHA to take marine mammals incidental to pile driving/removal and 
DTH activities during maintenance improvements to the existing MSF in 
Southeast Alaska. The application was deemed adequate and complete on 
November 23, 2020. The applicant also provided an addendum to their 
application on February 23, 2021 for the addition of eight piles, some 
changes to their shutdown zones, and minor changes to their take 
estimates due to the increase of in-water work days from the eight 
additional piles. The applicant's request is for take of eight species 
of marine mammals by Level B harassment only. Neither the AKDOT&PF nor 
NMFS expects serious injury or mortality to result from this activity 
and, therefore, an IHA is appropriate.

Description of Planned Activity

    The purpose of this project is to make repairs to the MSF. The 
existing facility has experienced deterioration in recent years and 
AKDOT&PF has conducted several repair projects. The facility is near 
the end of its useful life, and replacement of all the existing float 
structures is required to continue safe operation in the future. The 
planned project in Metlakatla is located approximately 24 kilometers 
(km) (15 miles (mi)) south of Ketchikan, in Southeast Alaska. 
Metlakatla, is on Annette Island, in the Prince of Whales-Hyder Census 
Area of Southeast Alaska. The Metlakatla Seaplane Facility is centrally 
located in the village of Metlakatla on the south shore of Port 
Chester.
    The planned project includes pile driving/removal and DTH over 2 
months (approximately 26 working days) beginning in August 2021. Pile 
installation and removal will be intermittent during this period, 
depending on weather, construction and mechanical delays, protected 
species shutdowns, and other potential delays and logistical 
constraints. Pile installation will occur intermittently during the 
work period, for durations of minutes to hours at a time. Approximately 
18 days of pile installation and 8 days of pile removal will occur 
using vibratory and impact pile driving and some DTH to stabilize the 
piles. These are discussed in further detail below. The total 
construction duration accounts for the time required to mobilize 
materials and resources and construct the project.
    Planned activities included as part of the project with potential 
to affect marine mammals include the noise generated by vibratory 
removal of steel pipe piles, vibratory and impact installation of steel 
pipe piles, and DTH to stabilize piles. Pile removal will be conducted 
using a vibratory hammer. Pile installation will be conducted using 
both a vibratory and impact hammer and DTH pile installation methods. 
Piles will be advanced to refusal using a vibratory hammer. After DTH 
pile installation, the final approximate 3.048 m (10 ft) of driving 
will be conducted using an impact hammer so that the structural 
capacity of the pile embedment can be verified. The pile installation 
methods used will depend on sediment depth and conditions at each pile 
location. Pile installation and removal will occur in waters 
approximately 6-7 m (20-23 ft) in depth.
    The project will involve the removal of 11 existing steel pipe 
piles (16-inch (in) diameter) that support the existing multiple-float 
structure. The multiple-float timber structure, which covers 8,600 
square ft, will also be removed. A new 4,800-square-ft single-float 
timber structure will be installed in the same general location. Six 
24-in diameter steel pipe piles will be installed to act as restraints 
for the new seaplane float. In addition, 12 temporary 24-in steel piles 
will be installed to support pile installation and removed following 
completion of construction.
    DTH pile installation involves drilling rock sockets into the 
bedrock to support installation of the 6 permanent piles and 12 
temporary piles. Rock sockets consist of inserting the pile in a 
drilled hole into the underlying bedrock after the pile has been driven 
through the overlying softer sediments to refusal by vibratory or 
impact methods. The pile is advanced farther into this drilled hole to 
properly secure the bottom portion of the pile into the rock. The depth 
of the rock socket varies, but 3.048-4.572 m (10-15 ft) is commonly 
required. The diameter of the rock socket is slightly larger than the 
pile being driven. Rock sockets are constructed using a DTH device with 
both rotary and percussion-type actions. Each device consists of a 
drill bit that drills through the bedrock using both rotary and pulse 
impact mechanisms. This breaks up the rock to allow removal of the 
fragments and insertion of the pile. The pile is usually advanced at 
the same time that drilling occurs. Drill cuttings are expelled from 
the top of the pile using compressed air. It is estimated that drilling 
rock sockets into the bedrock will take about 1-3 hours (hrs) per pile.
    Tension anchors will be installed in each of the six permanent 
piles. Tension anchors are installed within piles that are drilled into 
the bedrock below the elevation of the pile tip after the pile has been 
driven through the sediment layer to refusal. A 6- or 8-in diameter 
steel pipe casing will be inserted inside the larger diameter 
production pile. A rock drill will be inserted into the casing, and a 
6- to 8-in diameter hole will be drilled into bedrock with rotary and 
percussion drilling methods. The drilling work is contained within the 
steel pile casing and the steel pipe pile. The typical depth of the 
drilled hole varies, but 20-30 ft is common. Rock fragments will be 
removed through the top of the casing with compressed air. A steel rod 
will then be grouted into the drilled hole and affixed to the top of 
the pile. The purpose of a tension anchor is to secure the pile to the 
bedrock to withstand uplift forces. It is estimated that tension anchor 
installation will take about 1-2 hrs per pile.
    No concurrent pile driving is anticipated for this project.
    Please see Table 1 below for the specific amount of time required 
to install and remove piles.

[[Page 43192]]



                                                      Table 1--Pile Driving and Removal Activities
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                                                                  Impact                                  DTH pile
                                                                  strikes   Vibratory     DTH pile      installation      Total
                               Number of     Rock     Tension    per pile    duration   installation      (tension     duration of  Piles per    Total
    Pile diameter and type       piles     sockets    anchors    (duration   per pile   (rock socket)      anchor)       activity      day        days
                                                                    in      (minutes)   duration per    duration per     per pile    (range)
                                                                 minutes)              pile (minutes)  pile (minutes)    (hours)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Pile Installation
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Plumb Piles                4          4          4     20 (15)         15             180             120          5.5  0.5 (0-1)          8
 (Permanent).................
24-in Steel Batter Piles               2          2          2     20 (15)         15              90             120            4  0.5 (0-1)          4
 (Permanent).................
24-in Steel Piles (Temporary)         12         12          0     20 (15)         15              60             N/A          1.5    2 (1-3)          6
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Pile Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
16-in Steel Piles............         11        N/A        N/A         N/A         30             N/A             N/A          0.5    3 (2-4)          4
24-in Steel Piles (Temporary)         12        N/A        N/A         N/A         30             N/A             N/A          0.5    3 (2-4)          4
                              --------------------------------------------------------------------------------------------------------------------------
    Totals...................         29         18          6         N/A        N/A             N/A             N/A          N/A        N/A         26
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: DTH = down-the-hole; N/A = not applicable.

    A detailed description of the planned MSF project is provided in 
the Federal Register notice for the proposed IHA (86 FR 34203; June 29, 
2021).

Comments and Responses

    A notice of NMFS' proposal to issue and IHA to AKDOT&PF was 
published in the Federal Register on June 29, 2021 (86 FR 34203). That 
notice described, in detail, AKDOT&PF's activity, the marine mammal 
species that may be affected by the activity, and the anticipated 
effects on marine mammals. During the 30-day public comment period, 
NMFS received no public comments on this action.

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS' Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-stock-assessment-reports) 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 2 lists all species or stocks for which take is expected and 
authorized for this action, and summarizes information related to the 
population or stock, including regulatory status under the MMPA and 
Endangered Species Act (ESA) and potential biological removal (PBR), 
where known. For taxonomy, we follow Committee on Taxonomy (2020). PBR 
is defined by the MMPA as the maximum number of animals, not including 
natural mortalities, that may be removed from a marine mammal stock 
while allowing that stock to reach or maintain its optimum sustainable 
population (as described in NMFS' SARs). While no mortality is 
anticipated or authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS' stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS' U.S. Pacific and Alaska SARs (Carretta et al., 2020; Muto et al., 
2020). All MMPA stock information presented in Table 2 is the most 
recent available at the time of publication and is available in the 
2019 SARs (Caretta et al., 2020; Muto et al., 2020) and draft 2020 SARs 
(available online at: www.fisheries.noaa.gov/national/marine-mammal-protection/draft-marine-mammal-stock-assessment-reports).

                                                  Table 2--Marine Mammal Occurrence in the Project Area
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                     ESA/ MMPA status;   Stock abundance  (CV,
            Common name                  Scientific name              Stock           strategic (Y/N)      Nmin, most recent        PBR      Annual M/SI
                                                                                            \1\          abundance survey) \2\                   \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Balaenopteridae (rorquals):
    Minke Whale....................  Balaenoptera            Alaska................  -, -, N            N/A (see SAR, N/A, see          UND            0
                                      acutorostrata.                                                     SAR).
    Humpback Whale.................  Megaptera novaeangliae  Central N Pacific.....  -, -, Y            10,103 (0.3, 7,891,              83           26
                                                                                                         2006).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                            Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Delphinidae:
    Killer Whale...................  Orcinus orca..........  Alaska Resident.......  -, -, N            2,347 (N/A, 2347,                24            1
                                                                                                         2012).
                                                             Northern Resident.....  -, -, N            302 (N/A, 302, 2018)..          2.2          0.2

[[Page 43193]]

 
                                                             West Coast Transient..  -, -, N            349 (N/A, 349; 2018)..          3.5          0.4
    Pacific White-Sided Dolphin....  Lagenorhynchus          N Pacific.............  -, -, N            26,880 (N/A, N/A,               UND            0
                                      obliquidens.                                                       1990).
Family Phocoenidae (porpoises):
    Dall's Porpoise................  Phocoenoides dalli....  AK....................  -, -, N            83,400 (0.097, N/A,             UND           38
                                                                                                         1991).
    Harbor Porpoise................  Phocoena phocoena.....  Southeast Alaska        -, -, Y            see SAR (see SAR, see       see SAR           34
                                                              Inland waters.                             SAR, 2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion...............  Eumetopias jubatus....  Eastern DPS...........  T, D, Y            43,201 a (see SAR,             2592          112
                                                                                                         43,201, 2017).
Family Phocidae (earless seals):
    Harbor Seal....................  Phoca vitulina........  Clarence Strait.......  -, -, N            27,659 (see SAR,                746           40
                                                                                                         24,854, 2015).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\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-assessment-reports-region. CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable
  [explain if this is the case].
\3\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
  fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV associated
  with estimated mortality due to commercial fisheries is presented in some cases.

    A detailed description of the of the species likely to be affected 
by the project, including brief introductions to the species and 
relevant stocks as well as available information regarding population 
trends and threats, and information regarding local occurrence, were 
provided in the Federal Register notice for the proposed IHA (86 FR 
34203; June 29, 2021) since that time, we are not aware of any changes 
in the status of these species and stocks; therefore, detailed 
descriptions are not provided here. Please refer to that Federal 
Register notice for these descriptions. Please also refer to NMFS' 
website (https://www.fisheries.noaa.gov/find-species) for generalized 
species accounts.

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    Acoustic effects on marine mammals during the specified activity 
can occur from vibratory and impact pile driving as well as during DTH 
of the piles. The effects of underwater noise from the AKDOT&PF's 
planned activities have the potential to result in Level B behavioral 
harassment of marine mammals in the vicinity of the action area. The 
effects of pile driving on marine mammals are dependent on several 
factors, including the size, type, and depth of the animal; the depth, 
intensity, and duration of the pile driving sound; the depth of the 
water column; the substrate of the habitat; the standoff distance 
between the pile and the animal; and the sound propagation properties 
of the environment. With both types, it is likely that the pile driving 
could result in temporary, short-term changes in an animal's typical 
behavioral patterns and/or avoidance of the affected area. The Federal 
Register notice for the proposed IHA (86 FR 34203; June 29, 2021) 
included a discussion of the effects of anthropogenic noise on marine 
mammals, therefore that information is not repeated here; please refer 
to the Federal Register notice (86 FR 34203; June 29, 2021).

Anticipated Effects on Marine Mammal Habitat

    The main impact issue associated with the planned activity would be 
temporarily elevated sound levels and the associated direct effects on 
marine mammals. The most likely impact to marine mammal habitat occurs 
from pile driving effects on likely marine mammal prey (i.e., fish) 
near where the piles are installed. Impacts to the immediate substrate 
during installation and removal of piles 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. Impacts to substrate are therefore not discussed 
further. These potential effects are discussed in detail in the Federal 
Register notice for the proposed IHA (86 FR 34203; June 29, 2021) 
therefore that information is not repeated here; please refer to that 
Federal Register notice for that information.

Estimated Take

    This section provides an estimate of the number of incidental takes 
authorization through this IHA, which will inform both NMFS' 
consideration of ``small numbers'' and the negligible impact 
determination.
    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).
    Take of marine mammals incidental to the AKDOT&PF's pile driving 
and removal activities (as well as during DTH) could occur as a result 
of Level B harassment only. Below we describe how the potential take is 
estimated. As described previously, no mortality is anticipated or 
authorized for this

[[Page 43194]]

activity. Below we describe how the take is estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed or incur some 
degree of permanent hearing impairment; (2) the area or volume of water 
that will be ensonified above these levels in a day; (3) the density or 
occurrence of marine mammals within these ensonified areas; and, (4) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of takes, additional information that can qualitatively 
inform take estimates is also sometimes available (e.g., previous 
monitoring results or average group size). Below, we describe the 
factors considered here in more detail and present the planned take 
estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B harassment) or to incur 
permanent threshold shift (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 (e.g., frequency, predictability, duty cycle), the environment 
(e.g., bathymetry), and the receiving animals (hearing, motivation, 
experience, demography, behavioral context) and can be difficult to 
predict (Southall et al., 2007, Ellison et al., 2012). Based on what 
the available science indicates and the practical need to use a 
threshold based on a factor that is both predictable and measurable for 
most activities, NMFS uses a generalized acoustic threshold based on 
received level to estimate the onset of behavioral harassment. NMFS 
predicts that marine mammals are likely to be behaviorally harassed in 
a manner we consider Level B harassment when exposed to underwater 
anthropogenic noise above received levels of 120 dB reference pressure 
micro Pascal (re 1 [mu]Pa (rms)) for continuous (e.g., vibratory pile 
driving and DTH) and above 160 dB re 1 [mu]Pa (rms) for impulsive 
sources (e.g., impact pile driving). The AKDOT&PF's planned activity 
includes the use of continuous (vibratory pile driving, DTH) and 
impulsive (impact pile driving) sources, and therefore the 120 and 160 
dB re 1 [mu]Pa (rms) are applicable.
    Level A Harassment--NMFS' Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0) 
(Technical Guidance, 2018) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise. The 
technical guidance identifies the received levels, or thresholds, above 
which individual marine mammals are predicted to experience changes in 
their hearing sensitivity for all underwater anthropogenic sound 
sources, and reflects the best available science on the potential for 
noise to affect auditory sensitivity by:
    [ssquf] Dividing sound sources into two groups (i.e., impulsive and 
non-impulsive) based on their potential to affect hearing sensitivity;
    [ssquf] Choosing metrics that best address the impacts of noise on 
hearing sensitivity, i.e., sound pressure level (peak SPL) and sound 
exposure level (SEL) (also accounts for duration of exposure); and
    [ssquf] Dividing marine mammals into hearing groups and developing 
auditory weighting functions based on the science supporting that not 
all marine mammals hear and use sound in the same manner.
    These thresholds were developed by compiling and synthesizing the 
best available science, and are provided in Table 3 below. The 
references, analysis, and methodology used in the development of the 
thresholds are described in NMFS 2018 Technical Guidance, which may be 
accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
    DTH pile installation includes drilling (non-impulsive sound) and 
hammering (impulsive sound) to penetrate rocky substrates (Denes et al. 
2016; Denes et al. 2019; Reyff and Heyvaert 2019). DTH pile 
installation was initially thought be a primarily non-impulsive noise 
source. However, Denes et al. (2019) concluded from a study conducted 
in Virginia, nearby the location for this project, that DTH should be 
characterized as impulsive based on Southall et al. (2007), who stated 
that signals with a >3 dB difference in sound pressure level in a 
0.035-second window compared to a 1-second window can be considered 
impulsive. Therefore, DTH pile installation is treated as both an 
impulsive and non-impulsive noise source. In order to evaluate Level A 
harassment, DTH pile installation activities are evaluated according to 
the impulsive criteria and using 160 dB rms. Level B harassment 
isopleths are determined by applying non-impulsive criteria and using 
the 120 dB rms threshold which is also used for vibratory driving. This 
approach ensures that the largest ranges to effect for both Level A and 
Level B harassment are accounted for in the take estimation process.

                     Table 3--Thresholds Identifying the Onset of Permanent Threshold Shift
                                                [Auditory injury]
----------------------------------------------------------------------------------------------------------------
                                                     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.

[[Page 43195]]

 
Note: Peak sound pressure (Lpk) has a reference value of 1 [micro]Pa, and cumulative sound exposure level (LE)
  has a reference value of 1[micro]Pa\2\s. In this Table, thresholds are abbreviated to reflect American
  National Standards Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as
  incorporating frequency weighting, which is not the intent for this Technical Guidance. Hence, the subscript
  ``flat'' is being included to indicate peak sound pressure should be flat weighted or unweighted within the
  generalized hearing range. The subscript associated with cumulative sound exposure level thresholds indicates
  the designated marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds)
  and that the recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could
  be exceeded in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible,
  it is valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds, which include source levels and transmission loss 
coefficient.
Sound Propagation
    Transmission loss (TL) is the decrease in acoustic intensity as an 
acoustic pressure wave propagates out from a source. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. The general formula for underwater TL is:

TL = B * log<INF>10</INF>(R<INF>1</INF>/R<INF>2</INF>), where

B = transmission loss coefficient (assumed to be 15)
R<INF>1</INF> = the distance of the modeled SPL from the driven 
pile, and
R<INF>2</INF> = the distance from the driven pile of the initial 
measurement.

    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive conditions including in-water structures and 
sediments. Spherical spreading occurs in a perfectly unobstructed 
(free-field) environment not limited by depth or water surface, 
resulting in a 6 dB reduction in sound level for each doubling of 
distance from the source (20*log(range)). Cylindrical spreading occurs 
in an environment in which sound propagation is bounded by the water 
surface and sea bottom, resulting in a reduction of 3 dB in sound level 
for each doubling of distance from the source (10*log(range)). As is 
common practice in coastal waters, here we assume practical spreading 
loss (4.5 dB reduction in sound level for each doubling of distance). 
Practical spreading is a compromise that is often used under conditions 
where water depth increases as the receiver moves away from the 
shoreline, resulting in an expected propagation environment that would 
lie between spherical and cylindrical spreading loss conditions. 
Practical spreading was used to determine sound propagation for this 
project.
Sound Source Levels
    The intensity of pile driving sounds is greatly influenced by 
factors such as the type of piles, hammers, and the physical 
environment in which the activity takes place. There are source level 
measurements available for certain pile types and sizes from the 
similar environments recorded from underwater pile driving projects in 
Alaska that were evaluated and used as proxy sound source levels to 
determine reasonable sound source levels likely result from the 
AKDOT&PF's pile driving and removal activities (Table 4). Many source 
levels used were more conservative as the values were from larger pile 
sizes.

                                                              Table 4--Sound Source Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
Method and pile type                                      SSL at 10 meters                 Literature source              Federal Register sources \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Continuous (Vibratory Pile Driving and                         dB rms
 DTH).
16-in Steel Piles........................                        161                       Navy 2012, 2015............  A, B, C, H.
24-in Steel Piles........................                        161                       Navy 2012, 2015............  C, D, E, H, I.
24-in DTH \b\............................                        166                       Denes et al. 2016 (Table     B, C, F, G.
                                                                                            72) \b\.
8-in DTH \c\.............................                        166                       NMFS \c\...................
--------------------------------------------------------------------------------------------------------------------------------------------------------
 Impulsive (Impact Pile Driving and DTH)       dB rms          dB SEL          dB Peak
--------------------------------------------------------------------------------------------------------------------------------------------------------
24-in Steel Piles........................             193             181             210  Navy 2015..................  D, H, I.
24-in DTH \b\............................  ..............             154  ..............  Denes et al. 2016 \b\......
8-in DTH \c\.............................  ..............             144             170  Reyff 2020.................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Federal Register sources:
A: 84 FR 24490; May 28, 2019, City of Juneau Waterfront Improvement Project, Juneau, Alaska.
B: 85 FR 4278; January 24, 2020, Statter Harbor Improvement Project, Auke Bay, Alaska.
C: 85 FR 673; January 7, 2020, Tongass Narrows Ferry Berth Improvements, Ketchikan, Alaska.
D: 85 FR 19294; April 6, 2020, Port of Alaska's Petroleum and Cement Terminal, Anchorage, Alaska.
E: 84 FR 56767; October 23, 2019, Auke Bay Ferry Terminal Modifications and Improvements Project, Juneau, Alaska.
F: 85 FR 18196; April 1, 2020, Gastineau Channel Historical Society Sentinel Island Moorage Float Project, Juneau, Alaska.
G: 85 FR 12523; March 3, 2020, Ward Cove Cruise Ship Dock Project, Juneau, Alaska.
H: 83 FR 29749; June 26, 2018, City Dock and Ferry Terminal, Tenakee Springs, Alaska.
I: 82 FR 48987; October 23, 2017, Sand Point City Dock Replacement Project, Sand Point, Alaska.
\b\ DTH pile installation is treated as a continuous sound for Level B calculations and impulsive for Level A calculations.
\c\ Tension anchor installation (8-in DTH) is currently treated as DTH pile installation.
Notes: DTH = down-the-hole pile installation; SSL = sound source = level; dB = decibel; rms = root mean square; SEL = sound exposure level.

Level A Harassment
    In conjunction with the NMFS Technical Guidance (2018), in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we

[[Page 43196]]

anticipate that isopleths produced are typically going to be 
overestimates of some degree, which may result in some degree of 
overestimate of Level A harassment take. However, these tools offer the 
best way to predict appropriate isopleths when more sophisticated 3D 
modeling methods are not available, and NMFS continues to develop ways 
to quantitatively refine these tools, and will qualitatively address 
the output where appropriate. For stationary sources (such as from 
impact and vibratory pile driving and DTH), NMFS User Spreadsheet 
(2020) predicts the closest distance at which, if a marine mammal 
remained at that distance the whole duration of the activity, it would 
not incur PTS. Inputs used in the User Spreadsheet (Tables 5 and 6), 
and the resulting isopleths are reported below (Table 7).

  Table 5--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Vibratory Pile
                                                     Driving
----------------------------------------------------------------------------------------------------------------
         User spreadsheet input--vibratory pile driving spreadsheet Tab A.1 vibratory pile driving used
-----------------------------------------------------------------------------------------------------------------
                                                                                    24-in piles    24-in plumb/
                                                                    16-in piles      temporary     batter piles
                                                                     (removal)       (install/       permanent
                                                                                     removal)        (install)
----------------------------------------------------------------------------------------------------------------
Source Level (RMS SPL)..........................................             161             161             161
Weighting Factor Adjustment (kHz)...............................             2.5             2.5             2.5
Number of piles within 24-hr period.............................               4               4               4
Duration to drive a single pile (min)...........................              30              30              30
Propagation (xLogR).............................................              15              15              15
Distance of source level measurement (meters)...................              10              10              10
----------------------------------------------------------------------------------------------------------------


                    Table 6--NMFS Technical Guidance (2020) User Spreadsheet Input To Calculate PTS Isopleths for Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                User spreadsheet input--impact pile driving spreadsheet tab E.1 impact pile driving used
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                            24-in piles      8-in pile       8-in pile       8-in pile      24-in pile      24-in pile      24-in pile
                                            (permanent)        (DTH)           (DTH)           (DTH)           (DTH)           (DTH)           (DTH)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Level (Single Strike/shot SEL)...             181             144             144             144             154             154             154
Weighting Factor Adjustment (kHz).......               2               2               2               2               2               2               2
Number of strikes per pile..............              20          54,000         108,000         162,000          54,000          81,000         162,000
Minutes per pile........................  ..............              60             120             180              60              90             180
Number of piles per day.................               3               1               1               1               1               1               1
Propagation (xLogR).....................              15              15              15              15              15              15              15
Distance of source level measurement                  10              10              10              10              10              10              10
 (meters)...............................
--------------------------------------------------------------------------------------------------------------------------------------------------------


 Table 7--NMFS Technical Guidance (2020) User Spreadsheet Outputs To Calculate Level A Harassment PTS Isopleths
----------------------------------------------------------------------------------------------------------------
            User spreadsheet output                                   PTS isopleths (meters)
----------------------------------------------------------------------------------------------------------------
                                                                        Level A harassment
                                                ----------------------------------------------------------------
           Activity              Sound source        Low-         Mid-        High-
                                 level at 10 m    frequency    frequency    frequency      Phocid      Otariid
                                                  cetaceans    cetaceans    cetaceans
----------------------------------------------------------------------------------------------------------------
                                         Vibratory Pile Driving/Removal
----------------------------------------------------------------------------------------------------------------
16-in steel pile removal.....  161 SPL.........         10.8          1.0         16.0          6.6          0.5
24-in steel pile temporary     161 SPL.........         10.8          1.0         16.0          6.6          0.5
 installation and removal.
24-in steel pile permanent...  161 SPL.........         10.8          1.0         16.0          6.6          0.5
----------------------------------------------------------------------------------------------------------------
                                               Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
24-in steel permanent          181 SEL/193 SPL.        112.6          4.0        134.1         60.3          4.4
 installation (3 piles a day).
24-in steel permanent          181 SEL/193 SPL.         85.9          3.1        102.3         46.0          3.3
 installation (2 piles a day).
24-in steel permanent          181 SEL/193 SPL.         54.1          1.9         64.5         29.0          2.1
 installation (1 piles a day).
----------------------------------------------------------------------------------------------------------------
                                                       DTH
----------------------------------------------------------------------------------------------------------------
8-in steel (60 min)..........  144 SEL/166 SPL.         35.8          1.3         42.7         19.2          1.4
8-in steel (120 min).........  144 SEL/166 SPL.         56.9          2.0         67.8         30.4          2.2
8-in steel (180 min).........  144 SEL/166 SPL.         74.5          2.7         88.8         39.9          2.9
24-in steel (60 min).........  154 SEL/166 SPL.        166.3          5.9        198.1         89.0          6.5

[[Page 43197]]

 
24-in steel (90 min).........  154 SEL/166 SPL.        218.0          7.8        259.6        116.6          8.5
24-in steel (180 min)........  154 SEL/166 SPL.        346.0         12.3        412.1        185.2         13.5
----------------------------------------------------------------------------------------------------------------

Level B Harassment
    Utilizing the practical spreading loss model, the AKDOT&PF 
determined underwater noise will fall below the behavioral effects 
threshold of 120 dB rms for marine mammals at the distances shown in 
Table 8 for vibratory pile driving/removal, and DTH. With these radial 
distances, the largest Level B harassment zone calculated was for DTH 
at 11,659 m. For calculating the Level B harassment zone for impact 
driving, the practical spreading loss model was used with a behavioral 
threshold of 160 dB rms. The maximum radial distance of the Level B 
harassment zone for impact piling equaled 1,585 m for 24-in piles. 
Table 8 below provides all Level B harassment radial distances (m) 
during the AKDOT&PF's planned activities.

   Table 8--Radial Distances (Meters) to Relevant Behavioral Isopleths
------------------------------------------------------------------------
                                   Received level at  Level B harassment
            Activity                 10 meters (m)        zone (m) *
------------------------------------------------------------------------
                 Vibratory Pile Driving/Removal and DTH
------------------------------------------------------------------------
16-in steel piles...............  161 SPL...........  5,415 (calculated
                                                       5,412).
24-in steel piles...............  161 SPL...........  5,415 (calculated
                                                       5,412).
8-in and 24-in DTH..............  166 SPL...........  11,660 (calculated
                                                       11,659).
------------------------------------------------------------------------
                           Impact Pile Driving
------------------------------------------------------------------------
24-in steel piles...............  181 SEL/193 SPL...  1,585.
------------------------------------------------------------------------
* Numbers rounded up to nearest 5 meters. These specific rounded
  distances are for monitoring purposes rather than take estimation.

Marine Mammal Occurrence and Take Calculation and Estimation

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations. Potential exposures to impact pile driving, vibratory 
pile driving/removal and DTH noises for each acoustic threshold were 
estimated using group size estimates and local observational data. As 
shown above, distances to Level A harassment thresholds for project 
activities are relatively small in most cases and mitigation (i.e., 
shutdown zones) is expected to avoid Level A harassment from these 
activities. Accordingly, take by Level B harassment only will be 
considered for this action. Take by Level B harassment are calculated 
differently for some species based on monthly or daily sightings data 
and average group sizes within the action area using the best available 
data.
Minke Whales
    There are no density estimates of minke whales available in the 
project area. These whales are usually sighted individually or in small 
groups of two or three, but there are reports of loose aggregations of 
hundreds of animals (NMFS 2018). Dedicated surveys for cetaceans in 
Southeast Alaska found that minke whales were scattered throughout 
inland waters from Glacier Bay and Icy Strait to Clarence Strait 
(Dahlheim et al. 2009). All sightings were of single minke whales, 
except for a single sighting of multiple minke whales. Anecdotal 
observations suggest that minke whales do not enter Port Chester, and 
may be more rare in the project area (L. Bethel, personal 
communication, June 11, 2020 2020 as cited in the application). Based 
on the potential for one group of a group size of three whales entering 
the Level B harassment zone during the project, similar to what is 
observed in Tongass Narrows, NMFS authorizes, take of three minke 
whales over the 4-month project period by Level B harassment. No take 
by Level A harassment is authorized or anticipated to occur due to 
their rarer occurrence in the project area. In addition, the shutdown 
zones are larger than all the calculated Level A harassment isopleths 
for all pile driving/removal and DTH activities for cetaceans.
Humpback Whales
    There are no density estimates for humpback whales available in the 
project area. Use of Nichols Passage and Port Chester by humpback 
whales is common but intermittent and dependent on the presence of prey 
fish. No systematic studies have documented humpback whale abundance 
near Metlakatla. Anecdotal information from Metlakatla and Ketchikan 
suggest that humpback whales' utilization of the area is intermittent 
year-round and local mariners estimate that one to two humpback whales 
may be present in the Port Chester area on a daily basis during summer 
months (L. Bethel, personal communication, June 11, 2020 2020 as cited 
in the application). This is consistent with reports from Ketchikan, 
which suggest that humpback whales occur alone or in groups of two or 
three individuals and abundance is highest in August and September (84 
FR 34134; July 17, 2019). However, anecdotal reports suggest that 
humpback whale abundance is higher and occurrence is more regular in 
Metlakatla. Therefore,

[[Page 43198]]

NMFS authorizes two groups of two whales, up to four individuals per 
day, may be taken by Level B harassment for a total of 104 humpback 
whales (4 whales per day * 26 days = 104 humpback whales).
    Under the MMPA, humpback whales are considered a single stock 
(Central North Pacific); however, we have divided them here to account 
for distinct population segments (DPSs) listed under the ESA. Using the 
stock assessment from Muto et al. 2020 for the Central North Pacific 
stock (10,103 whales) and calculations in Wade et al. 2016; 9,487 
whales are expected to be from the Hawaii DPS and 606 from the Mexico 
DPS. Therefore, for purposes of consultation under the ESA, we 
anticipate that 7 whales of the total takes would be individuals from 
the Mexico DPS (104 x 0.061 = 6.3 rounded to 7). No take by Level A 
harassment is authorized or anticipated to occur due to their large 
size and ability to be visibly detected in the project area if an 
animal should approach the Level A harassment zone as well as the size 
of the Level A harassment zones, which are expected to be manageable 
for the protected species observers (PSOs). The calculated Level A 
isopleths for low-frequency cetaceans are 113 m or less with the 
exception of DTH of limited duration of 24-in piles where they range 
from 166.3-346.0 m. The shutdown zones (Table 10) are larger for all 
calculated Level A harassment isopleths during all pile driving 
activities (vibratory, impact and DTH) for all cetaceans.
Killer Whales
    There are no density estimates of killer whales available in the 
project area. Three distinct eco-types occur in Southeast Alaska 
(resident, transient and offshore whales; Ford et al., 1994; Dahlheim 
et al., 1997, 2008). Dahlheim et al. (2009) observed transient killer 
whales within Lynn Canal, Icy Strait, Stephens Passage, Frederick 
Sound, and upper Chatham Strait. As determined during a line-transect 
survey by Dalheim et al. (2008), the greatest number of transient 
killer whale observed in Southeast Alaska occurred in 1993 with 32 
animals seen over 2 months for an average of 16 sightings per month. 
Resident pods were also observed in Icy Strait, Lynn Canal, Stephens 
Passage, Frederick Sound and upper Chatham Straight (Dalheim et al. 
2008). Transient killer whales are often found in long-term stable 
social units (pods) of 1 to 16 whales. Average pod sizes in Southeast 
Alaska were 6 in spring, 5 in summer, and 4 in fall. Pod sizes of 
transient whales are generally smaller than those of resident social 
groups. Resident killer whales occur in pods ranging from 7 to 70 
whales that are seen in association with one another more than 50 
percent of the time (Dahlheim et al. 2009; NMFS 2016b). In Southeast 
Alaska, resident killer whale mean pod size was approximately 21.5 in 
spring, 32.3 in summer, and 19.3 in fall (Dahlheim et al. 2009). Killer 
whales are observed occasionally during summer throughout Nichols 
Passage, but their presence in Port Chester is unlikely. Anecdotal 
local information suggests that killer whales are rarely seen within 
the Port Chester area, but may be present more frequently in Nichols 
Passage and other areas around Gravina Island (L. Bethel, personal 
communication, June 11, 2020 2020 as cited in the application). To be 
conservative NMFS authorizes one killer whale pod of up to 15 
individuals once during the project could be taken by Level B 
harassment based on a pod of 12 killer whales that may be present each 
month similar to Tongass Narrows near Ketchikan. Additionally, a recent 
monitoring report for Tongass Narrows reported 10 individuals sighted 
and 10 Level B harassment takes of killer whales during May 2021. No 
take by Level A harassment is authorized or anticipated to occur to the 
ability to visibly detect these large whales and the small size of the 
Level A harassment zones. In addition, the shutdown zones are larger 
than all the calculated Level A harassment isopleths for all pile 
driving/removal and DTH activities for cetaceans.
Pacific White-Sided Dolphin
    There are no density estimates of Pacific white-sided dolphins 
available in the project area. Most observations of Pacific white-sided 
dolphins occur off the outer coast or in inland waterways near 
entrances to the open ocean. Pacific white-sided dolphins have been 
observed in Alaska waters in groups ranging from 20 to 164 animals, 
with the sighting of 164 animals occurring in Southeast Alaska near 
Dixon Entrance to the south of Metlakatla (Muto et al., 2018). In 
nearby Tongass Narrows, NMFS estimated that one group of 92 Pacific 
white-sided dolphin (median between 20 and 164) may occur over a period 
of 1 year (85 FR 673; January 7, 2020). There are no records of this 
species occurring in Port Chester, and it is uncommon for individuals 
to occur in the project area. Therefore, NMFS authorizes one large 
group of 92 dolphins may be taken by Level B harassment during the 
project. No take by Level A harassment authorized or anticipated as the 
Level A harassment isopleths are so small.
Dall's Porpoise
    There are no density estimates of Dall's porpoise available in the 
project area. Little information is available on the abundance of 
Dall's porpoise in the inland waters of Southeast Alaska. Dall's 
porpoise are most abundant in spring, observed with lower numbers in 
the summer, and lowest numbers in fall. Jefferson et al., 2019 presents 
abundance estimates for Dall's porpoise in these waters and found the 
abundance in summer (N = 2,680, CV = 19.6 percent), and lowest in fall 
(N = 1,637, CV = 23.3 percent). No systematic studies of Dall's 
porpoise abundance or distribution have occurred in Port Chester or 
Nichols Passage; however, Dall's porpoises have been consistently 
observed in Lynn Canal, Stephens Passage, upper Chatham Strait, 
Frederick Sound, and Clarence Strait (Dahlheim et al. 2009). The 
species is generally found in waters in excess of 600 ft (183 m) deep, 
which do not occur in Port Chester. If Dall's porpoises occur in the 
project area, they will likely be present in March or April, given the 
strong seasonal patterns observed in nearby areas of Southeast Alaska 
(Dahlheim et al. 2009). Dall's porpoises are seen once a month or less 
within Port Chester and Nichols Passage in groups of less than 10 
animals (L. Bethel, personal communication, June 11, 2020 as cited in 
the application).
    Dall's porpoises are not expected to occur in Port Chester because 
the shallow water habitat of the bay is atypical of areas where Dall's 
porpoises usually occur. Therefore, NMFS authorizes one group of Dall's 
porpoise (15 individuals) per month, similar to what was estimated in 
nearby Tongass Narrows, may be taken by Level B harassment for a total 
of 30 Dall's porpoises during the 26 days of in-water construction (2 
months * 15 porpoises per month = 30). No take by Level A harassment is 
authorized or anticipated to occur due to their rarer occurrence in the 
project area and the unlikelihood that they would enter the Level A 
harassment zone and remain long enough to incur PTS in the rare event 
that they are encountered. No take by Level A harassment is authorized 
or anticipated to occur, as the calculated isopleths for high-frequency 
cetaceans are 134 m or less during all activities except during DTH for 
24-in piles of limited duration where they are 198 m-412 m. The 
shutdown zones (Table 10) are larger for all calculated Level A 
harassment isopleths during all pile

[[Page 43199]]

driving activities (vibratory, impact and DTH) for all cetaceans.
Harbor Porpoise
    There are no density estimates of harbor porpoise available in the 
project area. Although there have been no systematic studies or 
observations of harbor porpoises specific to Port Chester or Nichols 
Passage, there is potential for them to occur within the project area.
    Abundance data for harbor porpoises in Southeast Alaska were 
collected during 18 seasonal surveys spanning 22 years, from 1991 to 
2012 (Dahlheim et al. 2015). During that study, a total of 81 harbor 
porpoises were observed in the southern inland waters of Southeast 
Alaska, including Clarence Strait. The average density estimate for all 
survey years in Clarence Strait was 0.02 harbor porpoises per square 
kilometer. There does not appear to be any seasonal variation in harbor 
porpoise density for the inland waters of Southeast Alaska (Dahlheim et 
al. 2015). Approximately one to two groups of harbor porpoises are 
observed each week in group sizes of up to 10 animals around Driest 
Point, located 5 km (3.1 mi) north of the project location (L. Bethel, 
personal communication, June 11, 2020 as cited in the application). 
Therefore, NMFS authorizes that 2 groups of 5 harbor porpoises (average 
group size of local sightings) per 5 days of in-water work may be taken 
by Level B harassment. Expressed in another way, this is an average of 
2 harbor porpoise per day of in-water work. Therefore, we estimate 52 
exposures over the course of the project (26 days * 2 porpoises per day 
= 52). No take by Level A harassment is authorized or anticipated to 
occur, as the calculated isopleths for high-frequency cetaceans are 134 
m or less during all activities except during DTH for 24-in piles of 
limited duration where they are 198 m-412 m. The shutdown zones (Table 
10) are larger for all calculated Level A harassment isopleths during 
all pile driving activities (vibratory, impact and DTH) for all 
cetaceans.
Harbor Seal
    There are no density estimates of harbor seals available in the 
project area. Harbor seals are commonly sighted in the waters of the 
inside passages throughout Southeast Alaska. Surveys in 2015 estimated 
429 (95 percent Confidence Interval [CI]: 102-1,203) harbor seals on 
the northwest coast of Annettte Island, between Metlakatla and Walden 
Point. An additional 90 (95 percent CI: 18-292) were observed along the 
southwest coast of Annette Island, between Metlakatla and Tamgas Harbor 
(NOAA 2019). The Alaska Fisheries Science Center identifies three 
haulouts in Port Chester (less than a mile from the project area) and 
three additional haulouts north of Driest Point (3.7 mi from the 
project are). Abundance estimates for these haulouts are not available, 
but they are all denoted as having had more than 50 harbor seals at one 
point in time (NOAA 2020). However, local biologists report only small 
numbers (fewer than 10) of harbor seals are regularly observed in Port 
Chester. As many as 10 to 15 harbor seals may utilize Sylburn Harbor, 
north of Metlakatla across Driest Point (R. Cook, personal 
communication, June 5, 2020 as cited in the application), as a haulout 
location. Therefore, NMFS authorizes 15 harbor seals may be taken by 
Level B harassment each day, for a total of 390 exposures (26 days * 15 
seals per day = 390). No take by Level A harassment is authorized or 
anticipated to occur, as the calculated isopleths are 60 m or less 
during all activities except during DTH for 24-in piles of limited 
duration where they are 89-186 m. In addition, the shutdown zones 
(Table 10) are larger for all calculated Level A harassment isopleths 
during all pile driving activities (vibratory, impact and DTH) for all 
pinnipeds.
Steller Sea Lion
    There are no density estimates of Steller sea lions available in 
the project area. Steller sea lions are common within the project area; 
however, systematic counts or surveys have not been completed in the 
area directly surrounding Metlakatla. Three haulouts are located within 
150 km (93 mi) of the project area (Fritz et al. 2016a); the nearest 
documented haulout is West Rock, about 45 km (28 mi) south of 
Metlakatla. West Rock had a count of 703 individuals during a June 2017 
survey and 1,101 individuals during a June 2019 survey (Sweeney et al. 
2017, 2019). Aerial surveys occurred intermittently between 1994 and 
2015, and averaged 982 adult Steller sea lions (Fritz et al., 2016b). 
Anecdotal evidence indicate that 3 to 4 Steller sea lions utilize a 
buoy as a haulout near the entrance of Port Chester, about 3.2 km (2 
mi) from the project location (L. Bethel, personal communication, June 
11, 2020 as cited in the application). Steller sea lions are not known 
to congregate near the cannery in Metlakatla. Anecdotal evidence 
suggests that the species assemblages and abundance in Metlakatla are 
similar to Tongass Narrows where 20 sea lions are estimated each day 
during July through September. A recent monitoring report for Tongass 
Narrows reported 41 individual sightings of Steller sea lions with 9 
takes by Level B harassment in May 2021. Therefore to be conservative, 
NMFS authorizes two groups of 10 Steller sea lions (20 Steller sea 
lions) may be taken by Level B harassment for a total of 520 Steller 
sea lions (26 days * 20 sea lions per day = 520). No take by Level A 
harassment is authorized or anticipated to occur as the largest Level A 
isopleth calculated was 13.5 m during DTH of 24-in piles and the 
remaining isopleths were less than 10 m. In addition, the shutdown 
zones (Table 10) are larger for all calculated Level A harassment 
isopleths during all pile driving activities (vibratory, impact and 
DTH) for all pinnipeds.
    Table 9 below summarizes the authorized take for all the species 
described above as a percentage of stock abundance.

                           Table 9--Take Estimates as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
                                                                          Level B
                 Species                         Stock (nEST)           harassment         Percent of stock
----------------------------------------------------------------------------------------------------------------
Minke Whale.............................  Alaska (N/A)..............              12  N/A.
Humpback Whale..........................  Central North Pacific                  104  Less than 1 percent.
                                           (10,103).
Killer Whale............................  Alaska Resident (2,347)...              15  0.6.a
                                          Northern Resident (302)...                  5.0.a
                                          West Coast Transient (349)                  4.3.a
Pacific White-Sided Dolphin.............  North Pacific (26,880)....              92  Less than 1 percent.
Dall's Porpoise.........................  Alaska (83,400) b.........              30  Less than 1 percent.
Harbor Porpoise.........................  Southeast Alaska (NA).....              52  NA.
Harbor Seal.............................  Clarence Strait (27,659)..             390  1.4.

[[Page 43200]]

 
Steller Sea Lion........................  Eastern U.S. (43,201).....             520  1.2.
----------------------------------------------------------------------------------------------------------------
a Take estimates are weighted based on calculated percentages of population for each distinct stock, assuming
  animals present would follow same probability of presence in project area.
b Jefferson et al. 2019 presents the first abundance estimates for Dall's porpoise in the waters of Southeast
  Alaska with highest abundance recorded in spring (N = 5,381, CV = 25.4 percent), lower numbers in summer (N =
  2,680, CV = 19.6 percent), and lowest in fall (N = 1,637, CV = 23.3 percent). However, NMFS currently
  recognizes a single stock of Dall's porpoise in Alaskan waters and an estimate of 83,400 Dall's porpoises is
  used by NMFS for the entire stock (Muto et al., 2020).

Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable impact on 
such species or stock and its habitat, paying particular attention to 
rookeries, mating grounds, and areas of similar significance, and on 
the availability of such 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 such 
activity or other means of effecting the least practicable adverse 
impact upon the affected species or stocks and their habitat (50 CFR 
216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully consider two primary factors:
    (1) The manner in which, and the degree to which, the successful 
implementation of the measure(s) is expected to reduce impacts to 
marine mammals, marine mammal species or stocks, and their habitat. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned) the likelihood of effective implementation (probability 
implemented as planned); and
    (2) The practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.

General

    The AKDOT&PF will follow mitigation procedures as outlined in their 
Marine Mammal Monitoring Plan and as described below. In general, if 
poor environmental conditions restrict visibility full visibility of 
the shutdown zone, pile driving installation and removal as well as DTH 
would be delayed.

Training

    The AKDOT&PF must ensure that construction supervisors and crews, 
the monitoring team, and relevant AKDOT&PF staff are trained prior to 
the start of construction activity subject to this IHA, 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.

Avoiding Direct Physical Interaction

    The AKDOT&PF must avoid direct physical interaction with marine 
mammals during construction activity. If a marine mammal comes within 
10 m of such activity, operations will cease and vessels will reduce 
speed to the minimum level required to maintain steerage and safe 
working conditions, as necessary to avoid direct physical interaction.

Shutdown Zones

    For all pile driving/removal and DTH activities, the AKDOT&PF will 
establish a shutdown zone for a marine mammal species that is greater 
than its corresponding Level A harassment zone (Table 10). The purpose 
of a shutdown zone is generally to define an area within which shutdown 
of the activity would occur upon sighting of a marine mammal (or in 
anticipation of an animal entering the defined area). The shutdown 
zones are larger than all the calculated Level A harassment isopleths 
for all pile driving/removal and DTH activities for cetaceans and 
pinnipeds.

                         Table 10--Pile Driving Shutdown Zones During Project Activities
----------------------------------------------------------------------------------------------------------------
                                                                                    Shutdown distance (meters)
             Activity                   Pile diameter       Pile type or number  -------------------------------
                                                                  of piles           Cetaceans       Pinnipeds
----------------------------------------------------------------------------------------------------------------
Vibratory Installation/Removal....  16- and 24-in........  Battered and Plumb...              50              50
DTH...............................  24-in................  Temporary............             200             200
                                                           Battered, Permanent..             260             120
                                                           Plumb, Permanent.....             415             200
DTH...............................  8-in.................  Permanent............             100              50
Impact............................  24-in................  3 piles..............             135             100
                                                           2 piles..............
                                                           1 pile...............             100
----------------------------------------------------------------------------------------------------------------


[[Page 43201]]

Soft Start

    The AKDOT&PF must use soft start techniques when impact pile 
driving. Soft start requires contractors to provide an initial set of 
three strikes from the hammer at reduced energy, followed by a 30-
second waiting period. Then two subsequent reduced-energy strike sets 
would occur. A soft start will be implemented at the start of each 
day's impact pile driving and at any time following cessation of impact 
pile driving for a period of 30 minutes or longer. Soft start is not 
required during vibratory pile driving and removal activities.
    Based on our evaluation of the applicant's planned measures, NMFS 
has determined that the planned mitigation measures provide the means 
of effecting the least practicable impact on the affected species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Monitoring and Reporting

    In order to issue an IHA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth, requirements pertaining to 
the monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
action area. Effective reporting is critical both to compliance as well 
as ensuring that the most value is obtained from the required 
monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
    [ssquf] Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, distribution, 
density);
    [ssquf] Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving or feeding areas);
    [ssquf] Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors;
    [ssquf] How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine mammals; or (2) 
populations, species, or stocks;
    [ssquf] Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
    [ssquf] Mitigation and monitoring effectiveness.

Monitoring Zones

    The AKDOT&PF will conduct monitoring to include the area within the 
Level B harassment presented in Table 8. Monitoring will include all 
areas where SPLs are equal to or exceed 120 dB rms (for vibratory pile 
driving/removal and DTH) and 160 dB rms (for impact pile driving). 
These zones provide utility for monitoring conducted for mitigation 
purposes (i.e., shutdown zone monitoring) by establishing monitoring 
protocols for areas adjacent to the shutdown zones. Monitoring of the 
Level B harassment zones enables observers to be aware of and 
communicate the presence of marine mammals in the project area, but 
outside the shutdown zone, and thus prepare for potential shutdowns of 
activity.

Pre-Start Clearance Monitoring

    Pre-start clearance monitoring must be conducted during periods of 
visibility sufficient for the lead PSO to determine the shutdown zones 
clear of marine mammals. Pile driving and DTH may commence when the 
determination is made.

Visual Monitoring

    Monitoring must take place from 30 minutes (min) prior to 
initiation of pile driving and DTH activity (i.e., pre-start clearance 
monitoring) through 30 min post-completion of pile driving and DTH 
activity. If a marine mammal is observed entering or within the 
shutdown zones, pile driving and DTH activity will be delayed or 
halted. If pile driving or DTH 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 or 15 min have passed without re-detection of 
the animal. Pile driving and DTH activity will 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.

PSO Monitoring Requirements and Locations

    The AKDOT&PF will establish monitoring locations as described in 
the Marine Mammal Monitoring Plan. PSOs will be responsible for 
monitoring, the shutdown zones, the Level B harassment zones, and the 
pre-clearance zones, as well as effectively documenting Level B 
harassment take. As described in more detail in the Reporting section 
below, they will also (1) document the frequency at which marine 
mammals are present in the project area, (2) document behavior and 
group composition (3) record all construction activities, and (4) 
document observed reactions (changes in behavior or movement) of marine 
mammals during each sighting. Observers will monitor for marine mammals 
during all in-water pile installation/removal and DTH associated with 
the project. The AKDOT&PF will monitor the project area to the extent 
possible based on the required number of PSOs, required monitoring 
locations, and environmental conditions. Monitoring will be conducted 
by PSOs from land. For all pile driving and DTH activities, a minimum 
of one observer must be assigned to each active pile driving and DTH 
location to monitor the shutdown zones. Two PSOs must be onsite during 
all in-water activities and will monitor from the best vantage point. 
Due to the remote nature of the area, the PSOs will meet with the 
future designated Contractor and AKDOT&PF to determine the most 
appropriate observation location(s) for monitoring during pile 
installation and removal. These observers must record all observations 
of marine mammals, regardless of distance from the pile being driven or 
during DTH.
    In addition, PSOs will work in shifts lasting no longer than 4 hrs 
with at least a 1-hr break between shifts, and will not perform duties 
as a PSO for more than 12 hrs in a 24[hyphen]hr period (to reduce PSO 
fatigue).
    Monitoring of pile driving will be conducted by qualified, NMFS-
approved PSOs. The AKDOT&PF shall adhere to the following conditions 
when selecting PSOs:
    [ssquf] PSOs must be independent (i.e., not construction personnel) 
and have no other assigned tasks during monitoring periods;

[[Page 43202]]

    [ssquf] At least one PSO must have prior experience performing the 
duties of a PSO during construction activities pursuant to a NMFS-
issued incidental take authorization;
    [ssquf] Other PSOs may substitute other relevant experience, 
education (degree in biological science or related field), or training;
    [ssquf] Where a team of three PSOs are required, a lead observer or 
monitoring coordinator shall be designated. The lead observer must have 
prior experience performing the duties of a PSO during construction 
activity pursuant to a NMFS-issued incidental take authorization; and
    [ssquf] PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA.
    The AKDOT&PF will ensure that the PSOs have the following 
additional qualifications:
    [ssquf] Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the water's surface 
with ability to estimate target size and distance; use of binoculars 
may be necessary to correctly identify the target;
    [ssquf] Experience and ability to conduct field observations and 
collect data according to assigned protocols;
    [ssquf] Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
    [ssquf] Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    [ssquf] Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates, times, and reason for implementation 
of mitigation (or why mitigation was not implemented when required); 
and marine mammal behavior; and
    [ssquf] 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.

Final Report

    The AKDOT&PF will submit a draft report to NMFS on all monitoring 
conducted under this IHA within 90 calendar days of the completion of 
monitoring or 60 calendar days prior to the requested issuance of any 
subsequent IHA for construction activity at the same location, 
whichever comes first. A final report must be prepared and submitted 
within 30 days following resolution of any NMFS comments on the draft 
report. If no comments are received from NMFS within 30 days of receipt 
of the draft report, the report shall be considered final. All draft 
and final marine mammal monitoring reports must be submitted to 
<a href="/cdn-cgi/l/email-protection#f4a4a6dabda0a4dab99b9a9d809b869d9a93a691849b868087b49a9b9595da939b82"><span class="__cf_email__" data-cfemail="e2b2b0ccabb6b2ccaf8d8c8b968d908b8c85b087928d909691a28c8d8383cc858d94">[email protected]</span></a> and <a href="/cdn-cgi/l/email-protection#9cd5c8ccb2d9fbfbf9eedcf2f3fdfdb2fbf3ea"><span class="__cf_email__" data-cfemail="28617c78066d4f4f4d5a6846474949064f475e">[email protected]</span></a>. The report 
must contain the informational elements described in the Marine Mammal 
Monitoring Plan and, at minimum, must include:
    [ssquf] Dates and times (begin and end) of all marine mammal 
monitoring;
    [ssquf] Construction activities occurring during each daily 
observation period, including:
    [cir] How many and what type of piles were driven and by what 
method (e.g., impact, vibratory, DTH);
    [cir] Total duration of driving time for each pile (vibratory 
driving) and number of strikes for each pile (impact driving); and
    [cir] For DTH, duration of operation for both impulsive and non-
pulse components.
    [ssquf] PSO locations during marine mammal monitoring;
    [ssquf] 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;
    [ssquf] Upon observation of a marine mammal, the following 
information:
    [cir] PSO who sighted the animal and PSO location and activity at 
time of sighting;
    [cir] Time of sighting;
    [cir] 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;
    [cir] Distance and bearing of each marine mammal observed to the 
pile being driven for each sighting (if pile driving and DTH was 
occurring at time of sighting);
    [cir] Estimated number of animals (min/max/best);
    [cir] Estimated number of animals by cohort (adults, juveniles, 
neonates, group composition etc.;
    [cir] Animal's closest point of approach and estimated time spent 
within the harassment zone; and
    [cir] 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).
    [ssquf] Detailed information about implementation of any mitigation 
(e.g., shutdowns and delays), a description of specific actions that 
ensued, and resulting changes in behavior of the animal, if any; and
    [ssquf] All PSO datasheets and/or raw sightings data.

Reporting of Injured or Dead Marine Mammals

    In the event that personnel involved in the construction activities 
discover an injured or dead marine mammal, the AKDOT&PF must report the 
incident to NMFS Office of Protected Resources (OPR) 
(<a href="/cdn-cgi/l/email-protection#e4b4b6caadb0b4caa98b8a8d908b968d8a83b681948b969097a48a8b8585ca838b92"><span class="__cf_email__" data-cfemail="29797b07607d7907644647405d465b40474e7b4c59465b5d5a6947464848074e465f">[email protected]</span></a>), NMFS (301-427-8401) and to the 
Alaska regional stranding network (877-925-7773) as soon as feasible. 
If the death or injury was clearly caused by the specified activity, 
the AKDOT&PF must immediately cease the specified activities until NMFS 
OPR is able to review the circumstances of the incident and determine 
what, if any, additional measures are appropriate to ensure compliance 
with the terms of this IHA. The AKDOT&PF will not resume their 
activities until notified by NMFS. The report must include the 
following information:
    [ssquf] Time, date, and location (latitude/longitude) of the first 
discovery (and updated location information if known and applicable);
    [ssquf] Species identification (if known) or description of the 
animal(s) involved;
    [ssquf] Condition of the animal(s) (including carcass condition if 
the animal is dead);
    [ssquf] Observed behaviors of the animal(s), if alive;
    [ssquf] If available, photographs or video footage of the 
animal(s); and
    [ssquf] General circumstances under which the animal was 
discovered.

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''

[[Page 43203]]

through harassment, NMFS considers other factors, such as the likely 
nature of any responses (e.g., intensity, duration), the context of any 
responses (e.g., critical reproductive time or location, migration), as 
well as effects on habitat, and the likely effectiveness of the 
mitigation. We also assess the number, intensity, and context of 
estimated takes by evaluating this information relative to population 
status. Consistent with the 1989 preamble for NMFS's implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into this 
analysis via their impacts on the environmental baseline (e.g., as 
reflected in the regulatory status of the species, population size and 
growth rate where known, ongoing sources of human-caused mortality, or 
ambient noise levels).
    As stated in the mitigation section, shutdown zones that are larger 
than the Level A harassment zones will be implemented, which, in 
combination with the fact that the zones are small to begin with, is 
expected to avoid the likelihood of Level A harassment for marine 
mammals species.
    Exposures to elevated sound levels produced during pile driving 
activities may cause behavioral disturbance of some individuals, but 
they are expected to be mild and temporary. Effects on individuals that 
are taken by Level B harassment, as enumerated in the Take Estimation 
section, on the basis of reports in the literature as well as 
monitoring from other similar activities, will likely be limited to 
reactions such as increased swimming speeds, increased surfacing time, 
or decreased foraging (if such activity were occurring) (e.g., Thorson 
and Reyff, 2006; Lerma, 2014). Most likely, individuals will simply 
move away from the sound source and be temporarily displaced from the 
areas of pile driving, although even this reaction has been observed 
primarily only in association with impact pile driving. These reactions 
and behavioral changes are expected to subside quickly when the 
exposures cease.
    During all impact driving, implementation of soft start procedures 
and monitoring of established shutdown zones will be required, 
significantly reducing the possibility of injury. Given sufficient 
notice through use of soft start (for impact driving), marine mammals 
are expected to move away from an irritating sound source prior to it 
becoming potentially injurious. In addition, PSOs will be stationed 
within the action area whenever pile driving/removal and DTH activities 
are underway. Depending on the activity, the AKDOT&PF will employ the 
use of two PSOs to ensure all monitoring and shutdown zones are 
properly observed.
    The project would likely not permanently impact any marine mammal 
habitat since the project will occur within the same footprint as 
existing marine infrastructure. The nearshore and intertidal habitat 
where the project will occur is an area of relatively high marine 
vessel traffic and some local individuals would likely be somewhat 
habituated to the level of activity in the area, further reducing the 
likelihood of more severe impacts. The closest pinniped haulouts are 
used by harbor seals and are less than a mile from the project area; 
however, for the reasons described immediately above (including the 
nature of expected responses and the duration of the project) impacts 
to reproduction or survival of individuals is not anticipated, much 
less effects on the species or stock. There are no other biologically 
important areas for marine mammals near the project area.
    In addition, impacts to marine mammal prey species are expected to 
be minor and temporary. Overall, the area impacted by the project is 
very small compared to the available habitat around Metlakatla. The 
most likely impact to prey will be temporary behavioral avoidance of 
the immediate area. During pile driving/removal and DTH activities, it 
is expected that fish and marine mammals would temporarily move to 
nearby locations and return to the area following cessation of in-water 
construction activities. Therefore, indirect effects on marine mammal 
prey during the construction are not expected to be substantial.
    In summary and as described above, the following factors primarily 
support our determination that the impacts resulting from this activity 
are not expected to adversely affect the species or stock through 
effects on annual rates of recruitment or survival:
    [ssquf] No mortality is anticipated or authorized;
    [ssquf] No take by Level A harassment is expected or authorized;
    [ssquf] Anticipated incidents of Level B harassment consist of, at 
worst, temporary modifications in behavior;
    [ssquf] The required mitigation measures (i.e., shutdown zones) are 
expected to be effective in reducing the effects of the specified 
activity;
    [ssquf] Minimal impacts to marine mammal habitat/prey are expected;
    [ssquf] The action area is located and within an active marine 
commercial area, and;
    [ssquf] There are no known biologically important areas in the 
vicinity of the project, with the exception of nearby harbor seal 
haulouts--however, as described above, exposure to the work conducted 
in the vicinity of the haulouts is not expected to impact the 
reproduction or survival of any individual seals.
    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 monitoring and mitigation 
measures, NMFS finds that the total marine mammal take from the planned 
activity will have a negligible impact on all affected marine mammal 
species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Section 101(a)(5)(A) and (D) of the MMPA for specified 
activities other than military readiness activities. The MMPA does not 
define small numbers and so, in practice, where estimated numbers are 
available, NMFS compares the number of individuals taken to the most 
appropriate estimation of abundance of the relevant species or stock in 
our determination of whether an authorization is limited to small 
numbers of marine mammals. When the predicted number of individuals to 
be taken is fewer than one third of the species or stock abundance, the 
take is considered to be of small numbers. Additionally, other 
qualitative factors may be considered in the analysis, such as the 
temporal or spatial scale of the activities.
    Take of six of the marine mammal stocks authorized will comprise at 
most approximately 1.4 percent or less of the stock abundance. There 
are no official stock abundances for harbor porpoise and minke whales; 
however, as discussed in greater detail in the Description of Marine 
Mammals in the Area of Specified Activities in the Federal Register 
notice of the proposed IHA (86 FR 34203; June 29, 2021), we believe for 
the abundance information that is available, the estimated takes are 
likely small percentages of the stock abundance. For harbor porpoise, 
the abundance for the Southeast Alaska stock is likely more represented 
by the aerial surveys that were conducted as these surveys had better 
coverage and were corrected for observer bias. Based on this data, the 
estimated take could potentially be approximately 4 percent of the 
stock abundance. However, this is unlikely and the percentage of the 
stock taken is likely lower as the take

[[Page 43204]]

estimates are conservative and the project occurs in a small footprint 
compared to the available habitat in Southeast Alaska. For minke 
whales, in the northern part of their range they are believed to be 
migratory and so few minke whales have been seen during three offshore 
Gulf of Alaska surveys that a population estimate could not be 
determined. With only twelve authorized takes for this species, the 
percentage of take in relation to the stock abundance is likely to be 
very small.
    Based on the analysis contained herein of the planned activity 
(including the mitigation and monitoring measures) and the anticipated 
take of marine mammals, NMFS finds that small numbers of marine mammals 
will be taken relative to the population size of the affected species 
or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    The project area does not spatially overlap any known subsistence 
hunting. The project area is a developed area with regular marine 
vessel traffic. Nonetheless, the AKDOT&PF provided advanced public 
notice of construction activities to reduce construction impacts on 
local residents, adjacent businesses, and other users of Port Chester 
and nearby areas. This included notification to nearby Alaska Native 
tribes that may have members who hunt marine mammals for subsistence. 
Currently, the Metlakatla Indian Community does not authorize the 
harvest of marine mammals for subsistence use (R. Cook, personal 
communication, June 5, 2020 as cited in the application).
    The planned project is not likely to adversely impact the 
availability of any marine mammal species or stocks that are commonly 
used for subsistence purposes or to impact subsistence harvest of 
marine mammals in the region because construction activities are 
localized and temporary and mitigation measures will be implemented to 
minimize disturbance of marine mammals in the project area. 
Accordingly, NMFS has determined that there will not be an unmitigable 
adverse impact on the availability of any marine mammals for taking for 
subsistence uses from the AKDOT&PF's planned activities.

Endangered Species Act

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally whenever we propose to authorize take for 
endangered or threatened species, in this case with the Alaska Regional 
Office (AKRO).
    NMFS is authorizing take of the Central North Pacific stock of 
humpback whales, including individuals from the Mexico DPS of humpback 
whales, which are listed under the ESA. The Permit and Conservation 
Division completed a Section 7 consultation with the AKRO for the 
issuance of this IHA. The AKRO's biological opinion states that the 
action is not likely to jeopardize the continued existence of the 
Mexico DPS of humpback whales.

Authorization

    As a result of these determinations, NMFS authorizes an IHA to the 
AKDOT&PF for conducting for the planned pile driving and removal 
activities as well as DTH during construction of the Metlakatla 
Seaplane Facility Refurbishment Project, Metlakatla, Alaska for one 
year, beginning August 2021, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated.

    Dated: August 3, 2021.
Catherine Marzin,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2021-16861 Filed 8-5-21; 8:45 am]
BILLING CODE 3510-22-P


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