[Federal Register Volume 86, Number 41 (Thursday, March 4, 2021)]
[Notices]
[Pages 12630-12656]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-04431]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

[RIN 0648-XA858]


Taking of Marine Mammals Incidental to Specific Activities; 
Taking of Marine Mammals Incidental to Pile Driving and Removal 
Activities During Construction of the Hoonah Marine Industrial Center 
Cargo Dock Project, Hoonah, Alaska

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

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

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SUMMARY: NMFS has received a request from the City of Hoonah (City) for 
authorization to take marine mammals incidental to pile driving and 
removal activities during construction upgrades of a cargo dock at the 
city-owned Hoonah Marine Industrial Center (HMIC) in Port Frederick 
Inlet on Chichagof Island in Hoonah, Alaska. Pursuant to the Marine 
Mammal Protection Act (MMPA), NMFS is requesting comments on its 
proposal to issue an incidental harassment authorization (IHA) to 
incidentally take marine mammals during the specified activities. NMFS 
is also requesting comments on a possible one-year renewal that could 
be issued under certain circumstances and if all requirements are met, 
as described in Request for Public Comments at the end of this notice. 
NMFS will consider public comments prior to making any final decision 
on the issuance of the requested MMPA authorizations and agency 
responses will be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than April 5, 
2021.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service and should be sent by electronic mail 
to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments must not exceed a 25-megabyte file 
size, including all attachments. All comments received are a part of 
the public record and will generally be posted online at https://

[[Page 12631]]

www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-
marine-mammal-protection-act without change. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: 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/permit/incidental-take-authorizations-under-marine-mammal-protection-act. 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 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.

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an IHA) 
with respect to potential impacts on the human environment. This action 
is consistent with categories of activities identified in Categorical 
Exclusion B4 (IHAs with no anticipated serious injury or mortality) of 
the Companion Manual for NOAA Administrative Order 216-6A, which do not 
individually or cumulatively have the potential for significant impacts 
on the quality of the human environment and for which we have not 
identified any extraordinary circumstances that would preclude this 
categorical exclusion. Accordingly, NMFS has preliminarily determined 
that the issuance of the proposed IHA qualifies to be categorically 
excluded from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On October 28, 2020 NMFS received a request from the City for an 
IHA to take marine mammals incidental to pile driving and removal 
during construction upgrades of a cargo dock at the HMIC in Port 
Frederick Inlet on Chichagof Island in Hoonah, Alaska. The application 
was deemed adequate and complete on February 2, 2021. The applicant's 
request is for take of nine species of marine mammals by Level B 
harassment and five species by Level A harassment. Neither the City nor 
NMFS expects serious injury or mortality to result from this activity 
and, therefore, an IHA is appropriate.

Description of Proposed Activity

Overview

    The purpose of this project is to make upgrades to the HMIC. 
Upgrades to the site include the installation of three breasting 
dolphins, a sheet pile bulk cargo dock, fender piles, and a catwalk. 
The proposed upgrades are needed to continue safely accommodating 
barges and other vessels delivering essential goods to the City.
    The City is only accessible by air and water. Small amounts of 
cargo are transported into the community by plane; however, the 
majority is delivered weekly by barges from April through September 
(AML 2020). When weather permits, front load barges utilize a gravel 
landing located next to the existing City dock. The gravel landing 
provides a makeshift location to unload heavy cargo using a ramp and 
forklifts. During winter months, inclement weather events, and for more 
frequent deliveries, locals utilizes the Alaska Marine Highway System 
(AMHS) ferries and the local ferry terminal.
    The existing gravel landing at HMIC was not originally designed for 
barges and requires an additional ramp and favorable weather conditions 
to safely unload cargo. Even during favorable weather, the space and 
depth places the barges and crew at risk, and the landing cannot safely 
accommodate the fleet of barges delivering to Hoonah. With the decrease 
in AMHS ferry service (due to State funding cuts) it is imperative that 
a reliable way to receive goods in the City is available.
    The HMIC cargo dock is one component of the HMIC, which is a phased 
approach to enhance the Hoonah waterfront and to provide infrastructure 
to support the cruise ship industry and various other maritime 
industries (see Figure 4 of the application). The purpose of HMIC cargo 
dock project is to make improvements to the existing gravel landing to 
enable barges to land during all conditions. The project is needed 
because the existing facility cannot provide consistent and safe 
berthing for barges. Once the project is completed, the City will be 
able to reliably receive goods year-round and in all weather 
conditions. Currently, Alaska Marine Line barges offers seasonal ramp 
barge service into the City; however, this project will allow for year-
round, weekly deliveries by ocean going barges.

Dates and Duration

    The applicant is requesting an IHA to conduct pile driving and 
removal over 110 working days (not necessarily consecutive) beginning 
in spring and extending through the summer of 2021 as needed. 
Approximately 50 days of vibratory and 28 days of impact hammering will 
occur. An additional 35 days of drilling/down-the-hole (DTH) will occur 
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. The 
duration also accounts for potential delays in material deliveries, 
equipment maintenance, inclement weather, and shutdowns that may occur 
to prevent impacts to marine mammals.

[[Page 12632]]

Specific Geographic Region

    The proposed project at the HMIC is located in Port Frederick 
Inlet, approximately 0.8 kilometers (km) (0.5 miles) northwest of 
downtown Hoonah 0.24 km (0.15 miles) east of the State of Alaska Ferry 
Terminal in Southeast Alaska; T43S, R61E, S20, Copper River Meridian, 
USGS Quadrangle Juneau A5 NE; latitude 58.11549 and longitude -135.4547 
(see Figure 1 below and see also Figure 1, 2, 3, and Appendix A, Sheet 
1 of the application).
    Port Frederick is a 24-km inlet that dips into northeast Chichagof 
Island from Icy Strait, leading to Neka Bay and Salt Lake Bay. The 
inlet varies between 4 and almost 6 km wide with a depth of up to 150 
meters (m) (see Figure 6 of the application). Near the proposed 
project, the inlet is 12 to 28 m deep (NOAA 2018). NMFS's ShoreZone 
Mapper details the proposed project site as a semi-protected/partially 
mobile/sediment or rock and sediment habitat class with gravel beaches 
environmental sensitivity index (NMFS 2020).
[GRAPHIC] [TIFF OMITTED] TN04MR21.004

Detailed Description of Specific Activity

    The project would involve installing breasting dolphins, a solid 
fill sheet pile dock, and fender.
    Construction of the three breasting dolphins would include:

[ssquf] Installation of 10 temporary 30-inch (in) diameter steel piles 
as templates to guide proper installation of permanent piles (these 
piles would be removed prior to project completion); and
[ssquf] Installation of 9 permanent 36-in diameter steel piles
    [cir] Breasting Dolphin 1--(1) vertical 36-in steel pile and (2) 
36-in batter steel piles
    [cir] Breasting Dolphin 2--(1) vertical 36-in steel pile and (2) 
36-in batter steel pile
    [cir] Breasting Dolphin 3--(1) vertical 36-in steel pile and (2) 
36-in batter steel pile

    Construction of the bulk cargo dock would include (see Figure 4; 
Appendix A: Sheets 3-4 of the application):

[ssquf] Installation of 20 temporary 30-in steel piles as templates to 
guide proper installation of permanent H-piles (these piles would be 
removed prior to project completion);
[ssquf] Installation of 12 permanent H-piles to guide proper 
installation of sheets;
[ssquf] Installation of 500 permanent sheet piles (130 linear feet); 
and
[ssquf] Filling the area within sheet piles with 9,600 cubic yards of 
fill

    Installation of the fender piles would include (see Figure 4; 
Appendix A: Sheet 3 of the application):

[ssquf] Installation of 20 temporary 30-in steel piles as templates to 
guide proper installation of permanent fender piles (these piles would 
be removed prior to project completion); and
[ssquf] Installation of 6 permanent 20-in fender piles in front of 
sheet pile cargo dock
Construction Sequence
    In-water construction of the HMIC cargo dock components is expected 
to occur via the following sequence:
    (1) Vibrate twenty 30-in temporary piles to use as a guide to 
install H-piles for the cargo dock.
    (2) Vibrate and impact 12 H-piles to depth to hold the sheets into 
place.
    (3) Remove the temporary piles.
    (4) Using the H-piles as a guide, vibrate and impact 500 sheets 
into place to create a barrier prior to placing fill.
    (5) Using an excavator place 9,600 cubic yards of fill within the 
newly constructed cargo dock frame.
    After the completion of the cargo dock, the barge will move over to 
install the six fender piles at the existing city dock face using the 
following sequence:
    (1) Vibrate 20 temporary 30-in piles a minimum of ten feet into 
bedrock to create a template to guide installation of the permanent 
piles.
    (2) Weld a frame around the temporary piles.
    (3) Within the frame: Vibrate, impact, and socket six permanent 20-
in fender piles into place.
    (4) Remove the frame and temporary piles.
    (5) Perform this sequence at the other six fender pile locations.
    The three breasting dolphins will be constructed as the barge moves 
off shore and will install temporary and permanent piles as follows:
    (1) Vibrate 10 temporary 30-in piles a minimum of ten feet into 
bedrock to

[[Page 12633]]

create a template to guide installation of the permanent piles.
    (2) Weld a frame around the temporary piles.
    (3) Within the frame: Vibrate, impact, and socket one vertical and 
two batter 36-in pile into place.
    (4) Remove the frame and temporary piles.
    (5) Perform this sequence at the second and third location working 
farther from the shoreline.
    Please see Table 1 below for the specific amount of time required 
to install and remove piles.
Installation and Removal of Temporary (Template) Piles
    Temporary 30-in steel piles would be installed and removed using a 
vibratory hammer (Table 1).
Installation of Permanent Piles
    The permanent H-piles, 20-in, and 36-in piles would be installed 
through sand and gravel with a vibratory hammer until advancement 
stops. Then, the pile will be driven to depth with an impact hammer. If 
design tip elevation is still not achieved, the contractor will utilize 
a drill to secure the pile. (Note: This DTH method can also be referred 
to as DTH drilling. It is referred to as DTH throughout this document.) 
Pile depths are expected to be approximately 40 to 70 feet (ft) below 
the mudline and estimated to take approximately 1.25-10.5 hours (hrs) 
per pile to complete.
    The permanent sheets would be installed using a vibratory hammer 
and impact hammer following the same criteria as above to achieve 
design tip elevation (Table 1). It is expected that it will take around 
20 minutes to install each sheet.

                                                                          Table 1--Pile Driving and Removal Activities
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                                                                                                         Project component
                                  --------------------------------------------------------------------------------------------------------------------------------------------------------------
                                   Temporary pile...........  Temporary pile...........                                        Permanent pile installation
                                   installation.............  removal..................
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                                                                                        Vibratory Hammer
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Diameter of Steel Pile (inches)..  30.......................  30.......................  36.......................  H-piles.................  Sheets..................  20.
# of Piles.......................  50.......................  50.......................  9........................  12......................  500 (130lf).............  6.
Max # Piles Vibrated per Day.....  4........................  4........................  4........................  4.......................  30 sheets...............  3.
Vibratory Time per Pile (min)....  15.......................  15.......................  15.......................  15......................  15......................  15.
Vibratory Time per Day (min).....  60.......................  60.......................  60.......................  60......................  450 (7.5 hr)............  45.
Number of Days...................  12.5.....................  12.5.....................  2.25.....................  3.......................  17......................  2.
Vibratory Time Total.............  12 hrs 30 mins...........  12 hrs 30 mins...........  2 hr 15 mins.............  3 hrs...................  292 hrs.................  1 hr 30 min.
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                                                                                          Impact Hammer
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Diameter of Steel Pile (inches)..  .........................  .........................  36.......................  H-piles.................  Sheets..................  20.
# of Piles.......................  .........................  .........................  9........................  12......................  500 (130lf).............  6.
Max # Piles Impacted per Day.....  .........................  .........................  2........................  5.......................  5 sheets................  2.
Impact Time per Pile (min).......  .........................  .........................  15.......................  5.......................  5.......................  5.
Impact Time per Day (min)........  .........................  .........................  30.......................  20......................  25......................  10.
Number of Days...................  .........................  .........................  4.5 day..................  3.......................  17 days.................  3.
Impact Time Total................  .........................  .........................  2 hr 15 mins.............  1 hr....................  1 hr 30 mins............  30 min.
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                                                                                          Drilling/DTH
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Diameter of Steel Pile (inches)..  .........................  .........................  36.......................  H-Piles.................  ........................  20.
Total Quantity...................  .........................  .........................  9........................  12......................  ........................  6.
Anchor Diameter..................  .........................  .........................  33.......................  20......................  ........................  20.
Max # Piles Anchored per Day.....  .........................  .........................  2........................  2.......................  ........................  2.
Time per Pile....................  .........................  .........................  5-10 hrs.................  3-4 hrs.................  ........................  1 hr.
Actual Time Spent Driving per      .........................  .........................  60 min...................  60 min..................  ........................  60 min.
 Pile.
Time per Day.....................  .........................  .........................  12 hrs (max).............  12 hrs (max)............  ........................  12 hrs (max).
Actual Time Spent Driving per Day  .........................  .........................  72 mins (1 hr 12 mins;     2 hrs (max).............  ........................  1 hr (max).
                                                                                          max).
Blows per Pile...................  .........................  .........................  27,000-54,000............  20,000..................  ........................  15,000.
Number of Days...................  .........................  .........................  15 days..................  17 days.................  ........................  3 days.
Drilling Total Time..............  .........................  .........................  45-90 hours..............  20 hours................  ........................  4 hours.
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    In addition to the activities described above, the proposed action 
will involve other in-water construction and heavy machinery 
activities. Other types of in-water work including with heavy machinery 
will occur using standard barges, tug boats, and positioning piles on 
the substrate via a crane (i.e., ``stabbing the pile''). Workers will 
be transported from shore to the barge work platform by a 7.62 m (25 
ft) skiff with a 125-250 horsepower motor. The travel distance will be 
less than 30.5 m (100 ft). There could be multiple shore-to-barge trips 
during the day; however, the area of travel will be relatively small 
and close to shore. We do not expect any of these other in-water 
construction and heavy machinery activities to take marine mammals. 
Therefore, these other in-water construction and heavy machinery 
activities will not be discussed further.
    For further details on the proposed action and project components, 
please refer to Section 1.2 of the application.
    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SARs; https://www.fisheries.noaa.gov/national/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's

[[Page 12634]]

website (https://www.fisheries.noaa.gov/find-species).
    Table 2 lists all species with expected potential for occurrence in 
the project area and summarizes information related to the population 
or stock, including regulatory status under the MMPA and ESA and 
potential biological removal (PBR), where known. Tagged sperm whales 
have been tracked within the Gulf of Alaska, and multiple whales have 
been tracked in Chatham Strait, in Icy Strait, and in the action area 
in 2014 and 2015 (http://seaswap.info/whaletrackerAccessed4/15/19). 
However, the known sperm whale habitat (these shelf-edge/slope waters 
of the Gulf of Alaska) are far outside of the action area. It is 
unlikely that sperm whales will occur in the action area where pile 
driving activities will occur because they are generally found in far 
deeper waters. Therefore, sperm whales are not being proposed for take 
authorization and not discussed further. 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's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. 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
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                                                                                         ESA/ MMPA status;   Stock abundance  (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Eschrichtiidae:
    Gray Whale......................  Eschrichtius robustus..  Eastern N Pacific......  -, -, N             26,960 (0.05, 25,849,         801        131
                                                                                                             2016).
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
                                                                (Hawaii and Mexico                           2006).
                                                                DPS).
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                                            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
                                                               West Coast Transient...  -, -, N             349 (na/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
                                                                                                             SAR, 2012).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (Eared Seals and
 Sea Lions):
    Steller Sea Lion................  Eumetopias jubatus.....  Western DPS............  E, D, Y             52,932 (see SAR,              318        255
                                                                                                             52,932, 2019).
                                                               Eastern DPS............  T, D, Y             43,201 a (see SAR,           2592        112
                                                                                                             43,201, 2017).
Family Phocidae (earless seals):
    Harbor Seal.....................  Phoca vitulina.........  Glacier Bay/Icy Strait.  -, -, N             7,455 (see SAR, 6,680,        120        104
                                                                                                             2017).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable [explain if this is the case].
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.

    All species that could potentially occur in the proposed survey 
areas are included in Table 2. In addition, the Northern sea otter 
(Enhydra lutris kenyoni) may be found in the project area. However, sea 
otters are managed by the U.S. Fish and Wildlife Service and are not 
considered further in this document.

[[Page 12635]]

Minke Whale

    In the North Pacific Ocean, minke whales occur from the Bering and 
Chukchi seas south to near the Equator (Leatherwood et al., 1982). In 
the northern part of their range, minke whales are believed to be 
migratory, whereas, they appear to establish home ranges in the inland 
waters of Washington and along central California (Dorsey et al. 1990). 
Minke whales are observed in Alaska's nearshore waters during the 
summer months (National Park Service (NPS) 2018). Minke whales are 
usually sighted individually or in small groups of 2-3, but there are 
reports of loose aggregations of hundreds of animals (NMFS 2018d). 
Minke whales are rare in the action area, but they could be 
encountered. During the construction of the first Icy Strait cruise 
ship berth, a single minke was observed during the 135-day monitoring 
period (June 2015 through January 2016) (BergerABAM 2016). During Berth 
II construction there was also only one reported sighting of a minke 
whale throughout the duration of monitoring (June 2019-October 2019; 
SolsticeAK 2020).
    No abundance estimates have been made for the number of minke 
whales in the entire North Pacific. However, some information is 
available on the numbers of minke whales in some areas of Alaska. Line-
transect surveys were conducted in shelf and nearshore waters (within 
30-45 nautical miles of land) in 2001-2003 from the Kenai Fjords in the 
Gulf of Alaska to the central Aleutian Islands. Minke whale abundance 
was estimated to be 1,233 (CV = 0.34) for this area (Zerbini et al., 
2006). This estimate has also not been corrected for animals missed on 
the trackline. The majority of the sightings were in the Aleutian 
Islands, rather than in the Gulf of Alaska, and in water shallower than 
200 m. So few minke whales were seen during three offshore Gulf of 
Alaska surveys for cetaceans in 2009, 2013, and 2015 that a population 
estimate for this species in this area could not be determined (Rone et 
al., 2017).

Humpback Whale

    The humpback whale is distributed worldwide in all ocean basins and 
a broad geographical range from tropical to temperate waters in the 
Northern Hemisphere and from tropical to near-ice-edge waters in the 
Southern Hemisphere. The humpback whales that forage throughout British 
Colombia and Southeast Alaska undertake seasonal migrations from their 
tropical calving and breeding grounds in winter to their high-latitude 
feeding grounds in summer. They may be seen at any time of year in 
Alaska, but most animals winter in temperate or tropical waters near 
Hawaii. In the spring, the animals migrate back to Alaska where food is 
abundant. The Central North Pacific stock of humpback whales are found 
in the waters of Southeast Alaska and consist of two distinct 
population segments (DPSs) listed under the ESA, the Hawaii DPS and the 
Mexico DPS.
    Within Southeast Alaska, humpback whales are found throughout all 
major waterways and in a variety of habitats, including open-ocean 
entrances, open-strait environments, near-shore waters, area with 
strong tidal currents, and secluded bays and inlets. They tend to 
concentrate in several areas, including northern Southeast Alaska. 
Patterns of occurrence likely follow the spatial and temporal changes 
in prey abundance and distribution with humpback whales adjusting their 
foraging locations to areas of high prey density (Clapham 2000).
    Humpback whales may be found in and around Chichagof Island, Icy 
Strait, and Port Frederick Inlet at any given time. While many humpback 
whales migrate to tropical calving and breeding grounds in winter, they 
have been observed in Southeast Alaska in all months of the year 
(Bettridge et al., 2015). Diet for humpback whales in the Glacier Bay/
Icy Strait area mainly consists of small schooling fish (capelin, 
juvenile walleye pollock, sand lance, and Pacific herring) rather than 
euphausiids (krill). They migrate to the northern reaches of Southeast 
Alaska (Glacier Bay) during spring and early summer following these 
fish and then move south towards Stephens Passage in early fall to feed 
on krill, passing the project area on the way (Krieger and Wing 1986). 
Over 32 years of humpback whale monitoring in the Glacier Bay/Icy 
Strait area reveals a substantial decline in population since 2014; a 
total of 164 individual whales were documented in 2016 during surveys 
conducted from June-August, making it the lowest count since 2008 
(Neilson et al., 2017).
    During construction of the first Icy Strait cruise ship berth from 
June 2015 through January 2016, humpback whales were observed in the 
action area on 84 of the 135 days of monitoring; most often in 
September and October. Up to 18 humpback sightings were reported on a 
single day (October 2, 2015), and a total of 226 Level B harassments 
were recorded during project construction (June 2015 through January 
2016) (BergerABAM 2016). Additionally, during construction of Icy 
Strait cruise ship Berth II in 2019, humpback whales were observed in 
the action area on 45 of the 51 days of monitoring; most often in July 
and September. Up to 24 humpback sightings were reported on a single 
day (July 30, 2019) during project construction (SolsticeAK 2020). In 
the project vicinity, humpback whales typically occur in groups of 1-2 
animals, with an estimated maximum group size of 8 animals.
    On October 9, 2019, a proposed rule to designate critical habitat 
for humpback whales was published in the Federal Register (84 FR 
54354). Proposed critical habitat for Mexico DPS humpback whales was 
divided into ten units and assigned a conservation rating based upon 
available data for the unit. Unit 10 encompasses Southeast Alaska, 
including Port Frederick and Icy Strait. The area is of medium 
conservation importance on a scale from very low to very high.

Gray Whale

    Gray whales are found exclusively in the North Pacific Ocean. The 
Eastern North Pacific stock of gray whales inhabit the Chukchi, 
Beaufort, and Bering Seas in northern Alaska in the summer and fall and 
California and Mexico in the winter months, with a migration route 
along the coastal waters of Southeast Alaska. Gray whales have also 
been observed feeding in waters off Southeast Alaska during the summer 
(NMFS 2018e).
    The migration pattern of gray whales appears to follow a route 
along the western coast of Southeast Alaska, traveling northward from 
British Columbia through Hecate Strait and Dixon Entrance, passing the 
west coast of Chichagof Island from late March to May (Jones et al. 
1984, Ford et al. 2013). Since the project area is on the east coast of 
Chichagof Island it is less likely there will be gray whales sighted 
during project construction; however, the possibility exists.
    During the 2016 construction of the first cruise ship terminal at 
Icy Strait Point and 2019 construction of cruise ship Berth II, no gray 
whales were seen monitoring periods (BergerABAM 2016; SolsticeAK 2020).

Killer Whale

    Killer whales have been observed in all oceans and seas of the 
world, but the highest densities occur in colder and more productive 
waters found at high latitudes. Killer whales are found throughout the 
North Pacific and occur along the entire Alaska coast, in British 
Columbia and Washington inland waterways, and along the outer coasts of 
Washington, Oregon, and California (NMFS 2018f).

[[Page 12636]]

    The Alaska Resident stock occurs from Southeast Alaska to the 
Aleutian Islands and Bering Sea. The Northern Resident stock occurs 
from Washington State through part of Southeast Alaska; and the West 
Coast Transient stock occurs from California through Southeast Alaska 
(Muto et al., 2018) and are thought to occur frequently in Southeast 
Alaska (Straley 2017).
    Transient killer whales can pass through the waters surrounding 
Chichagof Island, in Icy Strait and Glacier Bay, feeding on marine 
mammals. Because of their transient nature, it is difficult to predict 
when they will be present in the area. Whales from the Alaska Resident 
stock and the Northern Resident stock are thought to primarily feed on 
fish. Like the transient killer whales, they can pass through Icy 
Strait at any given time (North Gulf Oceanic Society 2018).
    Killer whales were observed on 11 days during construction of the 
first Icy Strait cruise ship berth during the135-day monitoring period 
(June 2015 through January 2016). Killer whales were observed a few 
times a month. Usually a singular animal was observed, but a group 
containing 8 individuals was seen in the action area on one occasion, 
for a total of 24 animals observed during in-water work (BergerABAM 
2016). During construction of the second Icy Strait cruise ship Berth 
II in 2019 (51 days), killer whales were observed on 8 days. Usually a 
single animal or pairs were observed, but a group containing 5 
individuals was seen in the action area on one occasion. A total of 20 
animals observed during in-water work on Berth II (SolsticeAK 2020).

Pacific White-Sided Dolphin

    Pacific white-sided dolphins are a pelagic species. They are found 
throughout the temperate North Pacific Ocean, north of the coasts of 
Japan and Baja California, Mexico (Muto et al., 2018). They are most 
common between the latitudes of 38[deg] North and 47[deg] North (from 
California to Washington). The distribution and abundance of Pacific 
white-sided dolphins may be affected by large-scale oceanographic 
occurrences, such as El Ni[ntilde]o, and by underwater acoustic 
deterrent devices (NPS 2018a).
    No Pacific white-sided dolphins were observed during construction 
of the first cruise ship berth during the135-day monitoring period 
(June 2015 through January 2016) (BergerABAM 2016). However, a pod of 
two Pacific white-sided dolphins were observed during construction of 
the second cruise ship Berth II (June 2019 through October 2019) 
(SolsticeAK 2020). They are rare in the action area, likely because 
they are pelagic and prefer more open water habitats than are found in 
Icy Strait and Port Frederick Inlet. 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 (Muto et al., 2018).

Dall's Porpoise

    Dall's porpoises are widely distributed across the entire North 
Pacific Ocean. They show some migration patterns, inshore and offshore 
and north and south, based on morphology and type, geography, and 
seasonality (Muto et al., 2018). They are common in most of the larger, 
deeper channels in Southeast Alaska and are rare in most narrow 
waterways, especially those that are relatively shallow and/or with no 
outlets (Jefferson et al., 2019). In Southeast Alaska, abundance varies 
with season.
    Jefferson et al. (2019) recently published a report with survey 
data spanning from 1991 to 2012 that studied Dall's porpoise density 
and abundance in Southeast Alaska. They found Dall's porpoise were most 
abundant in spring, observed with lower numbers in summer, and lowest 
in fall. Surveys found Dall's porpoise to be common in Icy Strait and 
sporadic with very low densities in Port Frederick (Jefferson et al., 
2019). During a 16-year survey of cetaceans in Southeast Alaska, Dall's 
porpoises were commonly observed during spring, summer, and fall in the 
nearshore waters of Icy Strait (Dahlheim et al., 2009). Dall's 
porpoises were observed on 2 days during the 135-day monitoring period 
(June 2015 through January 2016) of the construction of the first 
cruise ship berth (BergerABAM 2016). Both were single individuals 
transiting within the waters of Port Frederick in the vicinity of 
Halibut Island. During the second cruise ship Berth II construction a 
total of 21 Dall's porpoises were observed on 8 days (SolsticeAK 2020). 
Dall's porpoises generally occur in groups from 2-12 individuals (NMFS 
2018g).

Harbor Porpoise

    In the eastern North Pacific Ocean, the Bering Sea and Gulf of 
Alaska harbor porpoise stocks range from Point Barrow, along the Alaska 
coast, and the west coast of North America to Point Conception, 
California. The Southeast Alaska stock ranges from Cape Suckling, 
Alaska to the northern border of British Columbia. Within the inland 
waters of Southeast Alaska, harbor porpoises' distribution is clustered 
with greatest densities observed in the Glacier Bay/Icy Strait region 
and near Zarembo and Wrangell Islands and the adjacent waters of Sumner 
Strait (Dahlheim et al., 2015). Harbor porpoises also were observed 
primarily between June and September during construction of the Hoonah 
Berth I cruise ship terminal project. Harbor porpoises were observed on 
19 days during the 135-day monitoring period (June 2015 through January 
2016) (BergerABAM 2016) and seen either singularly or in groups from 
two to four animals. During the test pile program conducted at the 
Berth II project site in May 2018, eight harbor porpoises where 
observed over a 7-hour period (SolsticeAK 2018).
    There is no official stock abundance associated with the SARs for 
harbor porpoise. Both aerial and vessel based surveys have been 
conducted for this species. Aerial surveys of this stock were conducted 
in June and July 1997 and resulted in an observed abundance estimate of 
3,766 harbor porpoise (Hobbs and Waite 2010) and the surveys included a 
subset of smaller bays and inlets. Correction factors for observer 
perception bias and porpoise availability at the surface were used to 
develop an estimated corrected abundance of 11,146 harbor porpoise in 
the coastal and inside waters of Southeast Alaska (Hobbs and Waite 
2010). Vessel based spanning the 22-year study (1991-2012) found the 
relative abundance of harbor porpoise varied in the inland waters of 
Southeast Alaska. Abundance estimated in 1991-1993 (N = 1,076; percent 
CI = 910-1,272) was higher than the estimate obtained for 2006-2007 (N 
= 604; 95 percent CI = 468-780) but comparable to the estimate for 
2010-2012 (N = 975; 95 percent CI = 857-1,109; Dahlheim et al., 2015). 
These estimates assume the probability of detection directly on the 
trackline to be unity (g(0) = 1) because estimates of g(0) could not be 
computed for these surveys. Therefore, these abundance estimates may be 
biased low to an unknown degree. A range of possible g(0) values for 
harbor porpoise vessel surveys in other regions is 0.5-0.8 (Barlow 
1988, Palka 1995), suggesting that as much as 50 percent of the 
porpoise can be missed, even by experienced observers.
    Further, other vessel based survey data (2010-2012) for the inland 
waters of Southeast Alaska, calculated abundance estimates for the 
concentrations of harbor porpoise in the northern and southern regions 
of the inland waters (Dahlheim et al. 2015). The resulting abundance 
estimates are 398 harbor porpoise (CV = 0.12) in the northern inland 
waters (including Cross Sound, Icy Strait, Glacier Bay, Lynn

[[Page 12637]]

Canal, Stephens Passage, and Chatham Strait) and 577 harbor porpoise 
(CV = 0.14) in the southern inland waters (including Frederick Sound, 
Sumner Strait, Wrangell and Zarembo Islands, and Clarence Strait as far 
south as Ketchikan). Because these abundance estimates have not been 
corrected for g(0), these estimates are likely underestimates.
    The vessel based surveys are not complete coverage of harbor 
porpoise habitat and not corrected for bias and likely underestimate 
the abundance. Whereas, the aerial survey in 1997, although outdated, 
had better coverage of the range and is likely to be more of an 
accurate representation of the stock abundance (11,146 harbor porpoise) 
in the coastal and inside waters of Southeast Alaska.

Harbor Seal

    Harbor seals range from Baja California north along the west coasts 
of Washington, Oregon, California, British Columbia, and Southeast 
Alaska; west through the Gulf of Alaska, Prince William Sound, and the 
Aleutian Islands; and north in the Bering Sea to Cape Newenham and the 
Pribilof Islands. They haul out on rocks, reefs, beaches, and drifting 
glacial ice and feed in marine, estuarine, and occasionally fresh 
waters. Harbor seals are generally non-migratory and, with local 
movements associated with such factors as tide, weather, season, food 
availability and reproduction.
    Distribution of the Glacier Bay/Icy Strait stock, the only stock 
considered in this application, ranges along the coast from Cape 
Fairweather and Glacier Bay south through Icy Strait to Tenakee Inlet 
on Chichagof Island (Muto et al., 2018).
    The Glacier Bay/Icy Strait stock of harbor seals are common 
residents of the action area and can occur on any given day in the 
area, although they tend to be more abundant during the fall months 
(Womble and Gende 2013). A total of 63 harbor seals were seen during 19 
days of the 135-day monitoring period (June 2015 through January 2016) 
(BergerABAM 2016), while none were seen during the 2018 test pile 
program (SolsticeAK 2018). Harbor seals were primarily observed in 
summer and early fall (June to September). Harbor seals were seen 
singulary and in groups of two or more, but on one occasion, 22 
individuals were observed hauled out on Halibut Rock, across Port 
Frederick approximately 2,414 m (1.5 miles) from the location of pile 
installation activity (BergerABAM 2016). In 2019, a total of 33 harbor 
seals were seen during the Berth II project (SolsticeAK 2020).
    There are two known harbor seal haulouts within the project area. 
According to the AFSC list of harbor seal haulout locations, the 
closest listed haulout (id 1,349: Name CF39A) is located in Port 
Frederick, approximately 3,400 m west of the project area (AFSC 2018). 
The second haulout (id: 8; name: CE79A) is approximately 10,200 meters 
south of the project area (AFSC 2020).

Steller Sea Lion

    Steller sea lions range along the North Pacific Rim from northern 
Japan to California, with centers of abundance in the Gulf of Alaska 
and Aleutian Islands (Loughlin et al., 1984).
    Of the two Steller sea lion populations in Alaska, the Eastern DPS 
includes sea lions born on rookeries from California north through 
Southeast Alaska and the Western DPS includes those animals born on 
rookeries from Prince William Sound westward, with an eastern boundary 
set at 144[deg] W (NMFS 2018h). Both WDPS and EDPS Steller sea lions 
are considered in this application because the WDPS are common within 
the geographic area under consideration (north of Summer Strait) (Fritz 
et al., 2013, NMFS 2013).
    Steller sea lions are not known to migrate annually, but 
individuals may widely disperse outside of the breeding season (late-
May to early-July), leading to intermixing of stocks (Jemison et al. 
2013; Allen and Angliss 2015).
    Steller sea lions are common in the inside waters of Southeast 
Alaska. They are residents of the project vicinity and are common year-
round in the action area, moving their haulouts based on seasonal 
concentrations of prey from exposed rookeries nearer the open Pacific 
Ocean during the summer to more protected sites in the winter (Alaska 
Department of Fish & Game (ADF&G) 2018). During the construction of the 
existing Icy Strait cruise ship berth a total of 180 Steller sea lions 
were observed on 47 days of the 135 monitoring days, amounting to an 
average of 1.3 sightings per day (BergerABAM 2016). Steller sea lions 
were frequently observed in groups of two or more individuals, but lone 
individuals were also observed regularly (BergerABAM 2016). During a 
test pile program performed at the project location by the Hoonah 
Cruise Ship Dock Company in May 2018, a total of 15 Steller sea lions 
were seen over the course of 7 hours in one day (SolsticeAK 2018). 
During construction of Berth II, a total of 197 Steller sea lion 
sightings over 42 days in 2019 were reported, amounting to an average 
of 4.6 sightings per day (SolsticeAK2020). They can occur in groups of 
1-10 animals, but may congregate in larger groups near rookeries and 
haulouts (NMFS 2018h). No documented rookeries or haulouts are near the 
project area.
    Critical habitat has been defined in Southeast Alaska at major 
haulouts and major rookeries (50 CFR 226.202). The nearest rookery is 
on the White Sisters Islands near Sitka and the nearest major haulouts 
are at Benjamin Island, Cape Cross, and Graves Rocks. The White Sisters 
rookery is located on the west side of Chichagof Island, about 72 km 
southwest of the project area. Benjamin Island is about 60 km northeast 
of Hoonah. Cape Cross and Graves Rocks are both about 70 km west of 
Hoonah. Steller sea lions are known to haul out on land, docks, buoys, 
and navigational markers.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2018) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibel (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. Marine mammal hearing 
groups and their associated hearing ranges are provided in Table 3.

[[Page 12638]]



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

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

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

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

Description of Sound Sources

    This section contains a brief technical background on sound, on the 
characteristics of certain sound types, and on metrics used in this 
proposal inasmuch as the information is relevant to the specified 
activity and to a discussion of the potential effects of the specified 
activity on marine mammals found later in this document. For general 
information on sound and its interaction with the marine environment, 
please see, e.g., Au and Hastings (2008); Richardson et al. (1995); 
Urick (1983).
    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in hertz (Hz) or cycles per second. Wavelength is the 
distance between two peaks or corresponding points of a sound wave 
(length of one cycle). Higher frequency sounds have shorter wavelengths 
than lower frequency sounds, and typically attenuate (decrease) more 
rapidly, except in certain cases in shallower water. Amplitude is the 
height of the sound pressure wave or the ``loudness'' of a sound and is 
typically described using the relative unit of the decibel (dB). A 
sound pressure level (SPL) in dB is described as the ratio between a 
measured pressure and a reference pressure (for underwater sound, this 
is 1 microPascal ([mu]Pa)), and is a logarithmic unit that accounts for 
large variations in amplitude; therefore, a relatively small change in 
dB corresponds to large changes in sound pressure. The source level 
(SL) represents the SPL referenced at a distance of 1 m from the source 
(referenced to 1 [mu]Pa), while the received level is the SPL at the 
listener's position (referenced to 1 [mu]Pa).
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. Root mean square is calculated by squaring 
all of the sound amplitudes, averaging the squares, and then taking the 
square root of the average (Urick, 1983). Root mean square accounts for 
both positive and negative values; squaring the pressures makes all 
values positive so that they may be accounted for in the summation of 
pressure levels (Hastings and Popper, 2005). This measurement is often 
used in the context of discussing behavioral effects, in part because 
behavioral effects, which often result from auditory cues, may be 
better expressed through averaged units than by peak pressures.
    Sound exposure level (SEL; represented as dB re 1 [mu]Pa\2\-s) 
represents the total energy in a stated frequency band over a stated 
time interval or event, and considers both intensity and duration of 
exposure. The per-pulse SEL is calculated over the time window 
containing the entire pulse (i.e., 100 percent of the acoustic energy). 
SEL is a cumulative metric; it can be accumulated over a single pulse, 
or calculated over periods containing multiple pulses. Cumulative SEL 
represents the total energy accumulated by a receiver over a defined 
time window or during an event. Peak sound pressure (also referred to 
as zero-to-peak sound pressure or 0-pk) is the maximum instantaneous 
sound pressure measurable in the water at a specified distance from the 
source, and is represented in the same units as the rms sound pressure.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in a 
manner similar to ripples on the surface of a pond and may be either 
directed in a beam or beams or may radiate in all directions

[[Page 12639]]

(omnidirectional sources), as is the case for sound produced by the 
pile driving activity considered here. The compressions and 
decompressions associated with sound waves are detected as changes in 
pressure by aquatic life and man-made sound receptors such as 
hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound, which is 
defined as environmental background sound levels lacking a single 
source or point (Richardson et al., 1995). The sound level of a region 
is defined by the total acoustical energy being generated by known and 
unknown sources. These sources may include physical (e.g., wind and 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
(e.g., vessels, dredging, construction) sound. A number of sources 
contribute to ambient sound, including wind and waves, which are a main 
source of naturally occurring ambient sound for frequencies between 200 
Hz and 50 kilohertz (kHz) (Mitson, 1995). In general, ambient sound 
levels tend to increase with increasing wind speed and wave height. 
Precipitation can become an important component of total sound at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times. Marine mammals can contribute significantly to ambient sound 
levels, as can some fish and snapping shrimp. The frequency band for 
biological contributions is from approximately 12 Hz to over 100 kHz. 
Sources of ambient sound related to human activity include 
transportation (surface vessels), dredging and construction, oil and 
gas drilling and production, geophysical surveys, sonar, and 
explosions. Vessel noise typically dominates the total ambient sound 
for frequencies between 20 and 300 Hz. In general, the frequencies of 
anthropogenic sounds are below 1 kHz and, if higher frequency sound 
levels are created, they attenuate rapidly.
    The sum of the various natural and anthropogenic sound sources that 
comprise ambient sound at any given location and time depends not only 
on the source levels (as determined by current weather conditions and 
levels of biological and human activity) but also on the ability of 
sound to propagate through the environment. In turn, sound propagation 
is dependent on the spatially and temporally varying properties of the 
water column and sea floor, and is frequency-dependent. As a result of 
the dependence on a large number of varying factors, ambient sound 
levels can be expected to vary widely over both coarse and fine spatial 
and temporal scales. Sound levels at a given frequency and location can 
vary by 10-20 decibels (dB) from day to day (Richardson et al., 1995). 
The result is that, depending on the source type and its intensity, 
sound from the specified activity may be a negligible addition to the 
local environment or could form a distinctive signal that may affect 
marine mammals.
    Sounds are often considered to fall into one of two general types: 
Pulsed and non-pulsed (defined in the following). The distinction 
between these two sound types is important because they have differing 
potential to cause physical effects, particularly with regard to 
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see 
Southall et al. (2007) for an in-depth discussion of these concepts. 
The distinction between these two sound types is not always obvious, as 
certain signals share properties of both pulsed and non-pulsed sounds. 
A signal near a source could be categorized as a pulse, but due to 
propagation effects as it moves farther from the source, the signal 
duration becomes longer (e.g., Greene and Richardson, 1988).
    Pulsed sound sources (e.g., airguns, explosions, gunshots, sonic 
booms, impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986, 2005; Harris, 1998; NIOSH, 1998; ISO, 2003) and occur 
either as isolated events or repeated in some succession. Pulsed sounds 
are all characterized by a relatively rapid rise from ambient pressure 
to a maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or intermittent (ANSI, 1995; 
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, and active sonar systems. The 
duration of such sounds, as received at a distance, can be greatly 
extended in a highly reverberant environment.
    The impulsive sound generated by impact hammers is characterized by 
rapid rise times and high peak levels. Vibratory hammers produce non-
impulsive, continuous noise at levels significantly lower than those 
produced by impact hammers. Rise time is slower, reducing the 
probability and severity of injury, and sound energy is distributed 
over a greater amount of time (e.g., Nedwell and Edwards, 2002; Carlson 
et al., 2005). DTH is believed to produce sound with both impulsive and 
continuous characteristics (e.g., Denes et al., 2016).

Acoustic Effects on Marine Mammals

    We previously provided general background information on marine 
mammal hearing (see Description of Marine Mammals in the Area of 
Specified Activities). Here, we discuss the potential effects of sound 
on marine mammals.
    Note that, in the following discussion, we refer in many cases to a 
review article concerning studies of noise-induced hearing loss 
conducted from 1996-2015 (i.e., Finneran, 2015). For study-specific 
citations, please see that work. Anthropogenic sounds cover a broad 
range of frequencies and sound levels and can have a range of highly 
variable impacts on marine life, from none or minor to potentially 
severe responses, depending on received levels, duration of exposure, 
behavioral context, and various other factors. The potential effects of 
underwater sound from active acoustic sources can potentially result in 
one or more of the following: Temporary or permanent hearing 
impairment, non-auditory physical or physiological effects, behavioral 
disturbance, stress, and masking (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007; G[ouml]tz et 
al., 2009). The degree of effect is intrinsically related to the signal 
characteristics, received level, distance from the source, and duration 
of the sound exposure. In general, sudden, high level sounds can cause 
hearing loss, as can longer exposures to lower level sounds. Temporary 
or permanent loss of hearing will occur almost exclusively for noise 
within an animal's hearing range. We first describe specific 
manifestations of acoustic effects before providing discussion specific 
to pile driving and removal activities.
    Richardson et al. (1995) described zones of increasing intensity of 
effect that might be expected to occur, in relation to distance from a 
source and assuming that the signal is within an animal's hearing 
range. First is the area within which the acoustic signal would

[[Page 12640]]

be audible (potentially perceived) to the animal but not strong enough 
to elicit any overt behavioral or physiological response. The next zone 
corresponds with the area where the signal is audible to the animal and 
of sufficient intensity to elicit behavioral or physiological 
responsiveness. Third is a zone within which, for signals of high 
intensity, the received level is sufficient to potentially cause 
discomfort or tissue damage to auditory or other systems. Overlaying 
these zones to a certain extent is the area within which masking (i.e., 
when a sound interferes with or masks the ability of an animal to 
detect a signal of interest that is above the absolute hearing 
threshold) may occur; the masking zone may be highly variable in size.
    We describe the more severe effects (i.e., certain non-auditory 
physical or physiological effects) only briefly as we do not expect 
that there is a reasonable likelihood that pile driving may result in 
such effects (see below for further discussion). Potential effects from 
explosive impulsive sound sources can range in severity from effects 
such as behavioral disturbance or tactile perception to physical 
discomfort, slight injury of the internal organs and the auditory 
system, or mortality (Yelverton et al., 1973). Non-auditory 
physiological effects or injuries that theoretically might occur in 
marine mammals exposed to high level underwater sound or as a secondary 
effect of extreme behavioral reactions (e.g., change in dive profile as 
a result of an avoidance reaction) caused by exposure to sound include 
neurological effects, bubble formation, resonance effects, and other 
types of organ or tissue damage (Cox et al., 2006; Southall et al., 
2007; Zimmer and Tyack, 2007; Tal et al., 2015). The construction 
activities considered here do not involve the use of devices such as 
explosives or mid-frequency tactical sonar that are associated with 
these types of effects.
    Threshold Shift--Marine mammals exposed to high-intensity sound, or 
to lower-intensity sound for prolonged periods, can experience hearing 
threshold shift (TS), which is the loss of hearing sensitivity at 
certain frequency ranges (Finneran, 2015). TS can be permanent 
(permanent threshold shift (PTS)), in which case the loss of hearing 
sensitivity is not fully recoverable, or temporary (TTS), in which case 
the animal's hearing threshold would recover over time (Southall et 
al., 2007). Repeated sound exposure that leads to TTS could cause PTS. 
In severe cases of PTS, there can be total or partial deafness, while 
in most cases the animal has an impaired ability to hear sounds in 
specific frequency ranges (Kryter, 1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals, and there is no PTS data for cetaceans, but such 
relationships are assumed to be similar to those in humans and other 
terrestrial mammals. PTS typically occurs at exposure levels at least 
several decibels above (a 40-dB threshold shift approximates PTS onset; 
e.g., Kryter et al., 1966; Miller, 1974) that inducing mild TTS (a 6-dB 
threshold shift approximates TTS onset; e.g., Southall et al. 2007). 
Based on data from terrestrial mammals, a precautionary assumption is 
that the PTS thresholds for impulse sounds (such as impact pile driving 
pulses as received close to the source) are at least 6 dB higher than 
the TTS threshold on a peak-pressure basis and PTS cumulative sound 
exposure level thresholds are 15 to 20 dB higher than TTS cumulative 
sound exposure level thresholds (Southall et al., 2007). Given the 
higher level of sound or longer exposure duration necessary to cause 
PTS as compared with TTS, it is considerably less likely that PTS could 
occur.
    TTS is the mildest form of hearing impairment that can occur during 
exposure to sound (Kryter, 1985). While experiencing TTS, the hearing 
threshold rises, and a sound must be at a higher level in order to be 
heard. In terrestrial and marine mammals, TTS can last from minutes or 
hours to days (in cases of strong TTS). In many cases, hearing 
sensitivity recovers rapidly after exposure to the sound ends. Few data 
on sound levels and durations necessary to elicit mild TTS have been 
obtained for marine mammals.
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS, and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to 
serious. For example, a marine mammal may be able to readily compensate 
for a brief, relatively small amount of TTS in a non-critical frequency 
range that occurs during a time where ambient noise is lower and there 
are not as many competing sounds present. Alternatively, a larger 
amount and longer duration of TTS sustained during time when 
communication is critical for successful mother/calf interactions could 
have more serious impacts.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin (Tursiops truncatus), beluga whale (Delphinapterus 
leucas), harbor porpoise, and Yangtze finless porpoise (Neophocoena 
asiaeorientalis)) and three species of pinnipeds (northern elephant 
seal, harbor seal, and California sea lion) exposed to a limited number 
of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (Finneran, 2015). TTS was not observed in trained 
spotted (Phoca largha) and ringed (Pusa hispida) seals exposed to 
impulsive noise at levels matching previous predictions of TTS onset 
(Reichmuth et al., 2016). In general, harbor seals and harbor porpoises 
have a lower TTS onset than other measured pinniped or cetacean species 
(Finneran, 2015). Additionally, the existing marine mammal TTS data 
come from a limited number of individuals within these species. There 
are no data available on noise-induced hearing loss for mysticetes. For 
summaries of data on TTS in marine mammals or for further discussion of 
TTS onset thresholds, please see Southall et al. (2007), Finneran and 
Jenkins (2012), Finneran (2015), and NMFS (2018).
    Behavioral Effects--Behavioral disturbance may include a variety of 
effects, including subtle changes in behavior (e.g., minor or brief 
avoidance of an area or changes in vocalizations), more conspicuous 
changes in similar behavioral activities, and more sustained and/or 
potentially severe reactions, such as displacement from or abandonment 
of high-quality habitat. Behavioral responses to sound are highly 
variable and context-specific and any reactions depend on numerous 
intrinsic and extrinsic factors (e.g., species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day), as well as the interplay between factors (e.g., 
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007; 
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not 
only among individuals but also within an individual, depending on 
previous experience with a sound source, context, and numerous other 
factors

[[Page 12641]]

(Ellison et al., 2012), and can vary depending on characteristics 
associated with the sound source (e.g., whether it is moving or 
stationary, number of sources, distance from the source). Please see 
Appendices B-C of Southall et al. (2007) for a review of studies 
involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure. As noted, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically airguns or acoustic harassment 
devices) have been varied but often consist of avoidance behavior or 
other behavioral changes suggesting discomfort (Morton and Symonds, 
2002; see also Richardson et al., 1995; Nowacek et al., 2007). However, 
many delphinids approach low-frequency airgun source vessels with no 
apparent discomfort or obvious behavioral change (e.g., Barkaszi et 
al., 2012), indicating the importance of frequency output in relation 
to the species' hearing sensitivity.
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder, 2007; Weilgart, 2007; NRC, 
2005). However, there are broad categories of potential response, which 
we describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al.; 2004; Goldbogen et al., 2013a, 2013b). Variations in dive behavior 
may reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005, 2006; Gailey et 
al., 2007; Gailey et al., 2016).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from airgun surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of

[[Page 12642]]

predators have occurred (Connor and Heithaus, 1996). The result of a 
flight response could range from brief, temporary exertion and 
displacement from the area where the signal provokes flight to, in 
extreme cases, marine mammal strandings (Evans and England, 2001). 
However, it should be noted that response to a perceived predator does 
not necessarily invoke flight (Ford and Reeves, 2008), and whether 
individuals are solitary or in groups may influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress Responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most 
economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003).
    Auditory Masking--Sound can disrupt behavior through masking, or 
interfering with, an animal's ability to detect, recognize, or 
discriminate between acoustic signals of interest (e.g., those used for 
intraspecific communication and social interactions, prey detection, 
predator avoidance, navigation) (Richardson et al., 1995; Erbe et al., 
2016). Masking occurs when the receipt of a sound is interfered with by 
another coincident sound at similar frequencies and at similar or 
higher intensity, and may occur whether the sound is natural (e.g., 
snapping shrimp, wind, waves, precipitation) or anthropogenic (e.g., 
shipping, sonar, seismic exploration) in origin. The ability of a noise 
source to mask biologically important sounds depends on the 
characteristics of both the noise source and the signal of interest 
(e.g., signal-to-noise ratio, temporal variability, direction), in 
relation to each other and to an animal's hearing abilities (e.g., 
sensitivity, frequency range, critical ratios, frequency 
discrimination, directional discrimination, age or TTS hearing loss), 
and existing ambient noise and propagation conditions.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
when disrupting or altering critical behaviors. It is important to 
distinguish TTS and PTS, which persist after the sound exposure, from 
masking, which occurs during the sound exposure. Because masking 
(without resulting in TS) is not associated with abnormal physiological 
function, it is not considered a physiological effect, but rather a 
potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other

[[Page 12643]]

potentially important natural sounds such as those produced by surf and 
some prey species. The masking of communication signals by 
anthropogenic noise may be considered as a reduction in the 
communication space of animals (e.g., Clark et al., 2009) and may 
result in energetic or other costs as animals change their vocalization 
behavior (e.g., Miller et al., 2000; Foote et al., 2004; Parks et al., 
2007; Di Iorio and Clark, 2009; Holt et al., 2009). Masking can be 
reduced in situations where the signal and noise come from different 
directions (Richardson et al., 1995), through amplitude modulation of 
the signal, or through other compensatory behaviors (Houser and Moore, 
2014). Masking can be tested directly in captive species (e.g., Erbe, 
2008), but in wild populations it must be either modeled or inferred 
from evidence of masking compensation. There are few studies addressing 
real-world masking sounds likely to be experienced by marine mammals in 
the wild (e.g., Branstetter et al., 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand, 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    Potential Effects of the City's Activity--As described previously, 
the City proposes to conduct pile driving, including impact and 
vibratory driving (inclusive of DTH). 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. These behavioral changes may include 
(Richardson et al., 1995): Changing durations of surfacing and dives, 
number of blows per surfacing, or moving direction and/or speed; 
reduced/increased vocal activities; changing/cessation of certain 
behavioral activities (such as socializing or feeding); visible startle 
response or aggressive behavior (such as tail/fluke slapping or jaw 
clapping); avoidance of areas where sound sources are located; and/or 
flight responses.
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, or reproduction. Significant 
behavioral modifications that could lead to effects on growth, 
survival, or reproduction, such as drastic changes in diving/surfacing 
patterns or significant habitat abandonment are extremely unlikely in 
this area (i.e., shallow waters in modified industrial areas).
    Whether impact or vibratory driving, sound sources would be active 
for relatively short durations, with relation to potential for masking. 
The frequencies output by pile driving activity are lower than those 
used by most species expected to be regularly present for communication 
or foraging. We expect insignificant impacts from masking, and any 
masking event that could possibly rise to Level B harassment under the 
MMPA would occur concurrently within the zones of behavioral harassment 
already estimated for vibratory and impact pile driving, and which have 
already been taken into account in the exposure analysis.

Anticipated Effects on Marine Mammal Habitat

    The proposed activities would not result in permanent impacts to 
habitats used directly by marine mammals. The project location is 
within an area that is currently used by large shipping vessels and in 
between two existing, heavily-traveled docks, and within an active 
marine commercial and tourist area.
    The proposed activities may have potential short-term impacts to 
food sources such as forage fish. The proposed activities could also 
affect acoustic habitat (see masking discussion above), but meaningful 
impacts are unlikely. There are no known foraging hotspots, or other 
ocean bottom structures of significant biological importance to marine 
mammals present in the marine waters in the vicinity of the project 
area. Therefore, the main impact issue associated with the proposed 
activity would be temporarily elevated sound levels and the associated 
direct effects on marine mammals, as discussed previously. 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.
    Effects to Prey--Sound may affect marine mammals through impacts on 
the abundance, behavior, or distribution of prey species (e.g., 
crustaceans, cephalopods, fish, zooplankton). Marine mammal prey varies 
by species, season, and location and, for some, is not well documented. 
Here, we describe studies regarding the effects of noise on known 
marine mammal prey.
    Fish utilize the soundscape and components of sound in their 
environment to perform important functions such as foraging, predator 
avoidance, mating, and spawning (e.g., Zelick et al., 1999; Fay, 2009). 
Depending on their hearing anatomy and peripheral sensory structures, 
which vary among species, fishes hear sounds using pressure and 
particle motion sensitivity capabilities and detect the motion of 
surrounding water (Fay et al., 2008). The potential effects of noise on 
fishes depends on the overlapping frequency range, distance from the 
sound source, water depth of exposure, and species-specific hearing 
sensitivity, anatomy, and physiology. Key impacts to fishes may include 
behavioral responses, hearing damage, barotrauma (pressure-related 
injuries), and mortality.
    Fish react to sounds which are especially strong and/or 
intermittent low-frequency sounds, and behavioral responses such as 
flight or avoidance are the most likely effects. Short duration, sharp 
sounds can cause overt or subtle changes in fish behavior and local 
distribution. The reaction of fish to noise depends on the 
physiological state of the fish, past exposures, motivation (e.g., 
feeding, spawning, migration), and other environmental factors. 
Hastings and Popper (2005) identified several studies that suggest fish 
may relocate to avoid certain areas of sound energy. Additional studies 
have documented effects of pile driving on fish, although several are 
based on studies in support of large, multiyear bridge construction 
projects (e.g., Scholik and Yan, 2001, 2002; Popper and Hastings, 
2009).

[[Page 12644]]

Several studies have demonstrated that impulse sounds might affect the 
distribution and behavior of some fishes, potentially impacting 
foraging opportunities or increasing energetic costs (e.g., Fewtrell 
and McCauley, 2012; Pearson et al., 1992; Skalski et al., 1992; 
Santulli et al., 1999; Paxton et al., 2017). However, some studies have 
shown no or slight reaction to impulse sounds (e.g., Pena et al., 2013; 
Wardle et al., 2001; Jorgenson and Gyselman, 2009; Cott et al., 2012). 
More commonly, though, the impacts of noise on fish are temporary.
    SPLs of sufficient strength have been known to cause injury to fish 
and fish mortality. However, in most fish species, hair cells in the 
ear continuously regenerate and loss of auditory function likely is 
restored when damaged cells are replaced with new cells. Halvorsen et 
al. (2012a) showed that a TTS of 4-6 dB was recoverable within 24 hours 
for one species. Impacts would be most severe when the individual fish 
is close to the source and when the duration of exposure is long. 
Injury caused by barotrauma can range from slight to severe and can 
cause death, and is most likely for fish with swim bladders. Barotrauma 
injuries have been documented during controlled exposure to impact pile 
driving (Halvorsen et al., 2012b; Casper et al., 2013).
    The action area supports marine habitat for prey species including 
large populations of anadromous fish including Pacific salmon (five 
species), Cutthroat (Oncorhynchus clarkia) and Steelhead Trout (O. 
mykiss irideus), and Dolly Varden and other species of marine fish such 
as halibut, Northern Rock Sole (Lepidopsetta polyxystra), sculpins, 
Pacific Cod (Gadus macrocephalus), herring, and Eulachon (Thaleichthys 
pacificus) (NMFS 2020i). The most likely impact to fish from pile 
driving activities at the project areas would be temporary behavioral 
avoidance of the area. The duration of fish avoidance of an area after 
pile driving stops is unknown, but a rapid return to normal 
recruitment, distribution and behavior is anticipated. In general, 
impacts to marine mammal prey species are expected to be minor and 
temporary due to the expected short daily duration of individual pile 
driving events and the relatively small areas being affected.
    The following essential fish habitat (EFH) species may occur in the 
project area during at least one phase of their lifestage: Chum Salmon 
(Oncorhynchus keta), Pink Salmon (O. gorbuscha), Coho Salmon (O. 
kisutch), Sockeye Salmon (O. nerka), and Chinook Salmon (O. 
tshawytscha). No habitat areas of particular concern or EFH areas 
protected from fishing are identified near the project area (NMFS 
2020h). The closest documented anadromous fish steams to the project 
area are Halibut Creek (AWC: 114-34-10200) approximately 5,100 m north 
west of the proposed project site and Humpback Creek (AWC: 114-34-
10100) is approximately 7,600 m southwest of the proposed project site 
(ADF&G 2020a).
    The area impacted by the project is relatively small compared to 
the available habitat in Port Frederick Inlet and does not include 
habitat of particular importance relative to available habitat overall. 
Any behavioral avoidance by fish of the disturbed area would still 
leave significantly large areas of fish and marine mammal foraging 
habitat in the nearby vicinity. As described in the preceding, the 
potential for the City's construction to affect the availability of 
prey to marine mammals or to meaningfully impact the quality of 
physical or acoustic habitat is considered to be insignificant. Effects 
to habitat will not be discussed further in this document.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' and the negligible impact 
determination.
    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 City's pile driving and 
removal activities (as well as during DTH) could occur as a result of 
Level A and Level B harassment. Below we describe how the potential 
take is estimated. As described previously, no mortality is anticipated 
or proposed to be authorized for this activity. Below we describe how 
the take is estimated.
    Generally speaking, we estimate take by considering: (1) Acoustic 
thresholds above which NMFS believes the best available science 
indicates marine mammals will be behaviorally harassed or incur some 
degree of permanent hearing impairment; (2) the area or volume of water 
that will be ensonified above these levels in a day; (3) the density or 
occurrence of marine mammals within these ensonified areas; and, (4) 
and the number of days of activities. We note that while these basic 
factors can contribute to a basic calculation to provide an initial 
prediction of takes, additional information that can qualitatively 
inform take estimates is also sometimes available (e.g., previous 
monitoring results or average group size). Below, we describe the 
factors considered here in more detail and present the proposed take 
estimate.

Acoustic Thresholds

    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 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 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 City's proposed 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

[[Page 12645]]

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 4 below. The 
references, analysis, and methodology used in the development of the 
thresholds are described in NMFS 2018 Technical Guidance, which may be 
accessed at https://www.fisheries.noaa.gov/national/marine-mammal-protection/marine-mammal-acoustic-technical-guidance.
    The City's proposed activities includes the use of continuous non-
impulsive (vibratory pile driving, DTH) and impulsive (impact pile 
driving, DTH) sources, and therefore the 120 and 160 dB re 1 [mu]Pa 
(rms) criteria are applicable. 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 4--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.
Note: Peak sound pressure (Lpk) has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has
  a reference value of 1[mu]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 * log10(R1/R2),

where:

B = transmission loss coefficient (assumed to be 15)
R1 = the distance of the modeled SPL from the driven 
pile, and
R2 = 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

[[Page 12646]]

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.
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 (e.g., JASCO Reports--Denes et al., 2016 and Austin et al., 
2016) that were evaluated and used as proxy sound source levels to 
determine reasonable sound source levels likely result from the City's 
pile driving and removal activities (Table 5). Many source levels used 
were more conservation as the values were from larger pile sizes.

                  Table 5--Proposed Sound Source Levels
------------------------------------------------------------------------
                                  Sound source level
            Activity                 at 10 meters        Sound source
------------------------------------------------------------------------
                     Vibratory Pile Driving/Removal
------------------------------------------------------------------------
20-in fender pile permanent.....  161.9 SPL.........  The 20-in fender
30-in steel pile temporary        161.9 SPL.........   and 30-inch-
 installation.                    161.9 SPL.........   diameter source
30-in steel pile removal........                       level for
                                                       vibratory driving
                                                       are proxy from
                                                       median measured
                                                       source levels
                                                       from pile driving
                                                       of 30-inch-
                                                       diameter piles to
                                                       construct the
                                                       Ketchikan Ferry
                                                       Terminal (Denes
                                                       et al. 2016,
                                                       Table 72).
36-in steel pile permanent......  168.2 SPL.........  The 36-in-diameter
                                                       pile source level
                                                       is proxy from
                                                       median measured
                                                       source levels
                                                       from pile driving
                                                       of 48-in diameter
                                                       piles for the
                                                       Port of Anchorage
                                                       test pile project
                                                       (Austin et al.
                                                       2016, Table 16).
H-pile installation permanent...  168 SPL...........  The H-pile source
                                                       level is proxy
                                                       from median
                                                       measured source
                                                       levels from
                                                       vibratory pile
                                                       driving of H
                                                       piles for the
                                                       Port of Anchorage
                                                       test pile project
                                                       (Yurk et al. 2015
                                                       as cited in Denes
                                                       et al. 2016,
                                                       Appendix H Table
                                                       2).
Sheet pile installation.........  160 SPL...........  The sheet source
                                                       level is proxy
                                                       from median
                                                       measured source
                                                       levels from
                                                       vibratory pile
                                                       driving of 24-in
                                                       sheets for Berth
                                                       30 at the Port of
                                                       Oakland, CA
                                                       (Buehler et al.
                                                       2015; Table I.6-
                                                       2).
------------------------------------------------------------------------
                           Impact Pile Driving
------------------------------------------------------------------------
36-in steel pile permanent......  186.7 SEL/198.6     The 36-in diameter
                                   SPL.                pile source level
                                                       is a proxy from
                                                       median measured
                                                       source level from
                                                       impact hammering
                                                       of 48-in piles
                                                       for the Port of
                                                       Anchorage test
                                                       pile project
                                                       (Austin et al.,
                                                       2016, Tables 9
                                                       and 16).
20-in fender pile installation    161 SEL/174.8 SPL.  The 20-in diameter
 permeant.                                             pile source
                                                       levels are proxy
                                                       from median
                                                       measured source
                                                       levels from
                                                       vibratory driving
                                                       of 24-in piles
                                                       for the Kodiak
                                                       Ferry Terminal
                                                       project (Denes et
                                                       al. 2016).
H-pile installation permanent     163 SEL/177 SPL...  H-Pile and Sheets
 and Sheet pile installation.                          Impacting source
                                                       levels are proxy
                                                       from median
                                                       measured source
                                                       levels from pile
                                                       driving H-piles
                                                       and sheets for
                                                       the Port of
                                                       Anchorage test
                                                       pile project
                                                       (Yurk et al. 2015
                                                       as cited in Denes
                                                       et al. 2016,
                                                       Appendix H Table
                                                       1).
------------------------------------------------------------------------
                          DTH Pile Installation
------------------------------------------------------------------------
36-in steel pile permanent......  164 SEL/166 SPL...  The DTH sound
20-in fender pile installation    154 SEL/166 SPL...   source proxy of
 temporary.                       154 SEL/166 SPL...   164 dB SEL is
H-pile installation permanent                          from 42-in piles,
 (20-in hole).                                         Reyff 2020 and
                                                       Denes et al.
                                                       2019; while the
                                                       154 dB SEL is
                                                       based on 24-in
                                                       piles, Denes et
                                                       al. 2016.
------------------------------------------------------------------------

Level A Harassment
    When the NMFS Technical Guidance (2016) was published, in 
recognition of the fact that ensonified area/volume could be more 
technically challenging to predict because of the duration component in 
the new thresholds, we developed a User Spreadsheet that includes tools 
to help predict a simple isopleth that can be used in conjunction with 
marine mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which may result in some degree of 
overestimate of Level A harassment take. However, these tools offer the 
best way to predict appropriate isopleths

[[Page 12647]]

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 6 and 7), and the resulting isopleths are reported below (Table 
8).

                  Table 6--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
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                            30-in piles     30-in piles    20-in fender
                                                            (temporary      (temporary         piles        36-in piles       H-piles       Sheet piles
                                                             install)        removal)       (permanent)     (permanent)     (permanent)     (permanent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Level (RMS SPL)..................................           161.9           161.9           161.9           168.2             168             160
Weighting Factor Adjustment (kHz).......................             2.5             2.5             2.5             2.5             2.5             2.5
Number of piles within 24-hr period.....................               4               4               4               4               4              30
Duration to drive a single pile (min)...................              15              15              15              15              15              15
Propagation (xLogR).....................................              15              15              15              15              15              15
Distance of source level measurement (meters) +.........              10              10              10              10              11              10
--------------------------------------------------------------------------------------------------------------------------------------------------------


                    Table 7--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
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           20-in fender
                                            36-in piles     36-in pile         piles       20-in fender       H-pile       H-pile (DTH)     Sheet piles
                                            (permanent)        (DTH)        (permanent)     pile (DTH)      (permanent)                     (permanent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source Level (Single Strike/shot SEL)...           186.7             164             161             154             163             154             163
Weighting Factor Adjustment (kHz).......               2               2               2               2               2               2               2
Number of strikes per pile..............             100  ..............              35  ..............              35  ..............              35
Strike rate (avg. strikes per second)...  ..............              15  ..............              15  ..............              15  ..............
Number of piles per day.................               2               2               2               2               5               2               5
Propagation (xLogR).....................              15              15              15              15              15              15              15
Distance of source level measurement                  10              10              10              10              15              10              15
 (meters) +.............................
--------------------------------------------------------------------------------------------------------------------------------------------------------


                     Table 8--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 level at 10 m                                           High-
                                                                           Low-frequency   Mid-frequency     frequency        Phocid          Otariid
                                                                             cetaceans       cetaceans       cetaceans
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Vibratory Pile Driving/Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
20-in steel fender pile installation  161.9 SPL.........................             7.8             0.7            11.6             4.8             0.3
30-in steel pile temporary            161.9 SPL.........................             7.8             0.7            11.6             4.8             0.3
 installation.
30-in steel pile removal............  161.9 SPL.........................             7.8             0.7            11.6             4.8             0.3
36-in steel permanent installation..  168.2 SPL.........................            20.6             1.8            30.5            12.5             0.9
H-pile installation.................  168 SPL...........................            22.0             2.0            32.5            13.4             0.9
Sheet pile installation.............  160 SPL...........................            22.4             2.0            33.2            13.6             1.0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Impact Pile Driving
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in steel permanent installation..  186.7 SEL/198.6 SPL...............           602.7            21.4           717.9           322.5            23.5
20-in fender pile installation......  161 SEL/174.8 SPL.................             5.8             0.2             6.9             3.1            0.21
H-pile installation.................  163 SEL/177 SPL...................            21.8             0.8            25.9            11.6             0.8
Sheet pile installation.............  163 SEL/177 SPL...................            21.8             0.8            25.9            11.6             0.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                           DTH
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-in steel permanent installation..  164 SEL/166 SPL...................         1,225.6            43.6         1,459.9           655.9            47.8
20-in steel fender pile installation  154 SEL/166 SPL...................           264.1             9.4           314.5           141.3            10.3
H-pile installation.................  154 SEL/166 SPL...................           264.1             9.4           314.5           141.3            10.3
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 12648]]

Level B Harassment
    Utilizing the practical spreading loss model, the City determined 
underwater noise will fall below the behavioral effects threshold of 
120 dB rms for marine mammals at the distances shown in Table 9 for 
vibratory pile driving/removal, and DTH. With these radial distances, 
and due to the occurrence of landforms (See Figure 5 and 8 of the IHA 
Application), the largest Level B harassment zone calculated for 
vibratory pile driving for 36-in steel piles and H-piles were larger 
than the 15,700 m from the source where land masses block sound 
transmission. For DTH, the largest radial distance was 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 3,744 m for 36-in piles m. Table 9 below 
provides all Level B harassment radial distances (m) during the City's 
proposed activities.

                       Table 9--Radial Distances (Meters) to Relevant Behavioral Isopleths
----------------------------------------------------------------------------------------------------------------
                                                                                        Level B harassment zone
                Activity                          Received level at 10 meters                    (m) *
----------------------------------------------------------------------------------------------------------------
                                         Vibratory Pile Driving/Removal
----------------------------------------------------------------------------------------------------------------
20-in steel fender pile installation....  161.9 SPL.................................  6,215 (calculated 6,213).
30-in steel temporary installation......  161.9 SPL.................................  6,215 (calculated 6,213).
30-in steel removal.....................  161.9 SPL.................................  6,215 (calculated 6,213).
36-in steel permanent installation......  168.2 SPL.................................  15,700\a\ (calculated
                                                                                       16,343).
H-pile installation.....................  168 SPL...................................  15,700\a\ (calculated
                                                                                       17,434).
Sheet pile installation.................  160 SPL...................................  4,645 (calculated 4,642).
----------------------------------------------------------------------------------------------------------------
                                               Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
20-in fender pile installation..........  161 SEL/ 174.8 SPL........................  100 (calculated 97).
36-in steel permanent installation......  186.7 SEL/198.6 SPL.......................  3,745 (calculated 3,744).
H-pile and Sheet pile installation......  163 SEL/ 177 SPL..........................  205 (calculated 204).
----------------------------------------------------------------------------------------------------------------
                                                       DTH
----------------------------------------------------------------------------------------------------------------
20-in steel fender pile installation....  166 SPL...................................  11,660 (calculated
                                                                                       11,659).
36-in steel temporary installation......  166 SPL...................................  11,660 (calculated
                                                                                       11,659).
H-pile installation.....................  166 SPL...................................  11,660 (calculated
                                                                                       11,659).
----------------------------------------------------------------------------------------------------------------
* Numbers rounded up to nearest 5 meters. These specific rounded distances are for monitoring purposes rather
  than take estimation.
\a\ Although the calculated distance to Level B harassment thresholds extends these distances, all Level B
  harassment zones are truncated at 15,700m from the source where land masses block sound transmission.

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 
previously stated, take by Level B harassment as well as small numbers 
of take by Level A harassment will be considered for this action. Take 
by Level B and Level A 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. Take by 
Level A harassment is being proposed for three species (Dall's and 
harbor porpoise and harbor seal) where the Level A harassment isopleths 
are larger for pile driving of 36-in steel piles and DTH of 36-in 
piles, and is based on average group size multiplied by the number of 
days of impact pile driving for 36-in piles and DTH of 36-in piles. 
Distances to Level A harassment thresholds for other project activities 
(vibratory pile driving/removal, DTH and impact driving of smaller pile 
sizes) are considerably smaller compared to impact pile driving of 36-
in piles and DTH for 36-in piles, and mitigation is expected to avoid 
Level A harassment from these other activities.
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). One minke whale was sighted each year 
during the Hoonah cruise ship Berth I project (June 2015-January 2016; 
BergerABAM 2016) and during the Hoonah Berth II project (June 2019-
October 2019; SolsticeAK 2020).To be conservative based on group size, 
we predict that three minke whales in a group could be sighted each 
month over the 4-month project period for a total of 12 minke whale 
takes proposed for authorization by Level B harassment. No take by 
Level A harassment is proposed for authorization or anticipated to 
occur due to their rarer occurrence in the project area.
Humpback Whales
    There are no density estimates of humpback whales available in the 
project area. During the previous Hoonah Berth I project, humpback 
whales were observed on 84 of the 135 days of monitoring; most often in 
September and October (BergerABAM 2016). Additionally, during 
construction of the Hoonah Berth II project in 2019, humpback whales 
were observed in the action area on 45 of the 51 days of monitoring; 
most often in July and September. Up to 24 humpback sightings were 
reported on a single day (July 30, 2019), and a total of 108 
observations were recorded in harassment zones during project 
construction (SolsticeAK 2020).
    Based on a group size of eight animals, the general maximum group 
size observed in Southeast Alaska in all months of the year, NMFS 
estimates that 8 humpback whales could occur for each day of the 
project (110 days) for a total of 880 takes by Level B harassment. 
Under the MMPA, humpback whales are considered a single stock (Central

[[Page 12649]]

North Pacific); however, we have divided them here to account for 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 53 of those takes would be of 
individuals from the Mexico DPS (0.0601 proportion of the total takes). 
No take by Level A harassment is proposed for authorization 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.
Gray Whales
    There are no density estimates of gray whales available in the 
project area. Gray whales travel alone or in small, unstable groups, 
although large aggregations may be seen in feeding and breeding grounds 
(NMFS 2018e). Observations in Glacier Bay and nearby waters recorded 
two gray whales documented over a 10-year period (Keller et al., 2017). 
None were observed during Hoonah Berth I or II project monitoring 
(BergerABAM 2016, SolsticeAK 2020). We estimate a one gray whale x 
onesighting per month over the 4-month work period for a total of four 
gray whale takes proposed for authorization by Level B harassment. No 
take by Level A harassment is proposed for authorization or anticipated 
to occur due to their rarer occurrence in the project area, but also 
their large size and ability to be visibly detected in the project area 
if an animal should approach the Level A harassment zone.
Killer Whales
    There are no density estimates of killer whales available in the 
project area. Killer whales occur commonly in the waters of the project 
area, and could include members of several designated stocks that may 
occur in the vicinity of the proposed project area. Whales are known to 
use the Icy Strait corridor to enter and exit inland waters and are 
observed in every month of the year, with certain pods being observed 
inside Port Frederick passing directly in front of Hoonah. Group size 
of resident killer whale pods in the Icy Strait area ranges from 42 to 
79 and occur in every month of the year (Dahlheim pers. comm. to NMFS 
2015). As determined during a line-transect survey by Dalheim et al. 
(2008), the greatest number of transient killer whale observed occurred 
in 1993 with 32 animals seen over 2 months for an average of 16 
sightings per month. Killer whales were observed infrequently during 
construction of Hoonah Berth I project. Usually a singular animal was 
observed, but a group containing eight individuals was seen in the 
project area on one occasion. A total of 24 animals were observed 
during in-water work for the Hoonah Bert I project (BergerABAM 2016). 
During construction of the Hoonah Berth II project, killer whales were 
observed on 8 days. Usually a single animal or pairs were observed, but 
a group containing five individuals was seen in the project area on one 
occasion. A total of 20 animals were observed during in-water work on 
Hoonah Berth II project (SolsticeAK 2020). Using the largest group size 
for resident killer whales as discussed above, NMFS estimates that 79 
killer whales (residents and transients) could occur each month during 
the 4-month project period for a total of 316 takes by Level B 
harassment. No take by Level A harassment is proposed for authorization 
or anticipated to occur to the ability to visibly detect these large 
whales and in most cases the small size of the Level A harassment 
zones.
Pacific White-Sided Dolphin
    There are no density estimates of Pacific white-sided dolphins 
available in the project area. 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 (Muto et al., 2018). There were no Pacific white-sided 
dolphins observed during the 135-day monitoring period during the 
Hoonah Berth I project; however, a pod of two Pacific white-sided 
dolphins was observed during construction of the Hoonah Bert II project 
(SolsticeAK 2020). Using the largest group size for Pacific white-sided 
dolphins as discussed above, NMFS estimates 164 Pacific white-sided 
dolphins may be seen every other month over the 4-month project period 
for a total of 328 takes by Level B harassment. No take by Level A 
harassment is proposed or anticipated to occur as the largest Level A 
harassment isopleths calculated were 43.6 m during DTH of 36-in piles 
and 21.4 m during impact pile driving of 36-in piles. The remaining 
isopleths were all under 10 m.
Dall's Porpoise
    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). Dall's porpoise are common in Icy Strait and 
sporadic with very low densities in Port Frederick (Jefferson et al., 
2019). Dahlheim et al. (2008) observed 346 Dall's porpoise in Southeast 
Alaska (inclusive of Icy Strait) during the summer (June/July) of 2007 
for an average of 173 animals per month as part of a 17-year study 
period. During the previous Hoonah Berth I project, only two Dall's 
porpoise were observed, and were transiting within the waters of Port 
Frederick in the vicinity of Halibut Island. A total of 21 Dall's 
porpoises were observed on eight days during the Hoonah Berth II 
project in group sizes of 2 to 12 porpoise (SolsticeAK 2020).Therefore, 
NMFS' estimates 12 Dall's porpoise a week may be seen during the 4-
month project period for a total of 192 takes by Level B harassment. 
Because the calculated Level A harassment isopleths are larger for 
high-frequency cetaceans during DTH of 36-in piles (1,459.9 m) and 36-
in impact pile driving (717.9 m) and the applicant would have a reduced 
shutdown zone at 200 m, NMFS predicts that some take by Level A 
harassment may occur. It is estimated that two Dall's porpoise could be 
taken by Level A harassment every 5 days over a 20-day period (15 days 
of DTH of 36-in piles + 5 days of 36-in impact pile driving) for a 
total of 8 takes by Level A harassment.
Harbor Porpoise
    Dahlheim et al. (2015) observed 332 resident harbor porpoises occur 
in the Icy Strait area, and harbor porpoise are known to use the Port 
Frederick area as part of their core range. During the Hoonah Berth I 
project monitoring, a total of 32 harbor porpoise were observed over 19 
days during the 4-month project. The harbor porpoises were observed in 
small groups with the largest group size reported was four individuals 
and most group sizes consisting of three or fewer animals. During the 
test pile program conducted at the Berth II project site in May 2018, 
eight harbor porpoises where observed over a 7-hour period (SolsticeAK 
2018). During the Hoonah Berth II project, 120 harbor porpoises were 
observed June through October. The largest group size reported was 
eight individuals, and most group sizes consisting of four or fewer 
animals (SolsticeAK 2020). NMFS estimates that four harbor porpoises 
per day could occur in the project area over the 4-month project period 
(110 days)

[[Page 12650]]

for a total of 440 takes by Level B harassment. Because the calculated 
Level A harassment isopleths are larger for high-frequency cetaceans 
during DTH of 36-in piles (1,459.9 m) and 36-in impact pile driving 
(717.9 m) and the applicant would have a reduced shutdown zone at 200 
m, NMFS predicts that some take by Level A harassment may occur. It is 
estimated that four harbor porpoise could be taken by Level A 
harassment every 5 days over a 20-day period (15 days of DTH of 36-in 
piles + 5 days of 36-in impact pile driving) for a total of 16 takes by 
Level A harassment.
Harbor Seal
    There are no density estimates of harbor seals available in the 
project area. Keller et al. (2017) observed an average of 26 harbor 
seal sightings each month between June and August of 2014 in Glacier 
Bay and Icy Strait. During the monitoring of the Hoonah Berth I 
project, harbor seals typically occur in groups of one to four animals 
and a total of 63 seals were observed during 19 days of the 135-day 
monitoring period. In 2019, a total of 33 harbor seals were seen during 
the Hoonah Berth II project. Only solo individuals where sighted during 
that time (SolsticeAK 2020). NMFS estimates that three harbor seals per 
group, and two groups a day, could occur in the project area each month 
during the 4-month project period (110 days) for a total of 660 takes 
by Level B harassment. Because the calculated Level A harassment 
isopleths are larger for phocids during DTH of 36-in piles (655.9 m) 
and 36-in impact pile driving (322.5 m), compared with the proposed 
shutdown zone at 200 m, NMFS predicts that some take by Level A 
harassment may occur. It is estimated that one group of three harbor 
seals a day could be taken by Level A harassment over a 20-day period 
(15 days of DTH of 36-in piles + 5 days of 36-in impact pile driving) 
for a total of 60 takes by Level A harassment.
Steller Sea Lion
    There are no density estimates of Steller sea lions available in 
the project area. NMFS expects that Steller sea lion presence in the 
action area will vary due to prey resources and the spatial 
distribution of breeding versus non-breeding season. In April and May, 
Steller sea lions are likely feeding on herring spawn in the action 
area. Then, most Steller sea lions likely move to the rookeries along 
the outside coast (away from the action area) during breeding season, 
and would be in the action area in greater numbers in August and later 
months (J. Womble, NPS, pers. comm. to NMFS AK Regional Office, March 
2019). However, Steller sea lions are also opportunistic predators and 
their presence can be hard to predict.
    Steller sea lions typically occur in groups of 1-10 animals, but 
may congregate in larger groups near rookeries and haulouts. The 
previous Hoonah Berth I project observed a total of 180 Steller sea 
lion sightings over 135 days in 2015, amounting to an average of 1.3 
sightings per day (BergerABAM 2016). During a test pile program 
performed at the project location by the Hoonah Cruise Ship Dock 
Company in May 2018, a total of 15 Steller sea lions were seen over the 
course of 7 hours in one day (SolsticeAK 2018). During construction of 
the Hoonah Berth II project, a total of 197 Steller sea lion sightings 
over 42 days were reported, amounting to an average of 4.6 sightings 
per day (SolsticeAK 2020). NMFS estimates that five Steller sea lions 
per day could occur in the project area each month during the 4-month 
project period (110 days) for a total of 550 takes by Level B 
harassment, with 39 of those anticipated being from the Western DPS 
(0.0702 proportion of the total animals (L. Jemison draft unpublished 
Steller sea lion data, 2019). There is some evidence of Steller sea 
lions remaining in areas where there is a reliable food source. Should 
a Steller sea lion go undetected by a Protected Species Observer (PSO) 
and later observed within the Level A harassment zone, the City 
proposes mitigation measures (e.g., shutdowns), and it would be 
unlikely that an animal would accumulate enough exposure for PTS to 
occur. Therefore, no take by Level A harassment is proposed or 
anticipated to occur as the largest Level A isopleths calculated were 
47.8 m during DTH of 36-in piles and 23.5 m during impact pile driving 
of 36-in piles. The remaining isopleths were approximately 10 m or 
less.
    Table 10 below summarizes the proposed estimated take for all the 
species described above as a percentage of stock abundance.

                      Table 10--Proposed Take Estimates as a Percentage of Stock Abundance
----------------------------------------------------------------------------------------------------------------
                                Stock  (NEST)       Level A           Level B
           Species                                harassment        harassment            Percent of stock
----------------------------------------------------------------------------------------------------------------
Minke Whale..................  N/A............               0  12................  N/A.
Humpback Whale...............  Central North                 0  880...............  8.7.
                                Pacific.
Gray Whale...................  Eastern North                 0  4.................  Less than 1 percent.
                                Pacific
                                (27,000).
Killer Whale.................  Alaska Resident  ..............  256...............  \a\ 10.9
                                (2,347).                     0  33................  \a\ 10.9
                               Northern                         27................  \a\ 11.1.
                                Resident (302).                 (Total 316).......
                               West Coast
                                Transient
                                (243).
Pacific White-Sided Dolphin..  North Pacific                 0  328...............  Less than 1 percent.
                                (26,880).
Dall's Porpoise..............  Alaska (83,400)               8  144...............  Less than 1 percent.
                                Sec.  \b\.
Harbor Porpoise..............  NA.............              16  440...............  NA.
Harbor Seal..................  Glacier Bay/Icy              60  660...............  8.9.
                                Strait (7,455).
Steller Sea Lion.............  Eastern U.S.                  0  511...............  ............................
                                (43,201).                       39................  1.2
                               Western U.S.                     (Total 550).......  Less than 1 percent.
                                (53,624).
----------------------------------------------------------------------------------------------------------------
\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).


[[Page 12651]]

Proposed Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to 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 City would 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 City must ensure that construction supervisors and crews, the 
monitoring team, and relevant City 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 City must avoid direct physical interaction with marine mammals 
during construction activity. If a marine mammal comes within 10 m of 
such activity, operations must cease and vessels must 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 City would 
establish a shutdown zone for a marine mammal species that is greater 
than its corresponding Level A harassment zone; except for a few 
circumstances during impact pile driving and DTH, where the shutdown 
zone is smaller (reduced to 200 m) than the Level A harassment zone for 
high frequency cetaceans and phocids due to the practicability of 
shutdowns on the applicant and to the potential difficulty of observing 
these animals in the larger Level A harassment zones. The calculated 
PTS isopleths were rounded up to a whole number to determine the actual 
shutdown zones that the applicant will operate under (Table 11). 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).

                         Table 11--Pile Driving Shutdown Zones During Project Activities
----------------------------------------------------------------------------------------------------------------
                                                                  Shutdown zones
                                 -------------------------------------------------------------------------------
   Pile size, type, and method                                         High-
                                  Low- frequency  Mid- frequency     frequency        Phocid          Otariid
                                     cetaceans       cetaceans       cetaceans
----------------------------------------------------------------------------------------------------------------
                                         Vibratory Pile Driving/Removal
----------------------------------------------------------------------------------------------------------------
20-in steel fender pile                       10              10              15              10              10
 installation...................
30-in steel pile temporary                    10              10              15              10              10
 installation...................
30-in steel pile removal........              10              10              15              10              10
36-in steel permanent                         25              10              35              15              10
 installation...................
H-pile installation.............              35              10              35              15              10
Sheet pile installation.........              25              10              35              15              10
----------------------------------------------------------------------------------------------------------------
                                               Impact Pile Driving
----------------------------------------------------------------------------------------------------------------
36-in steel permanent                        625              25           * 200           * 200              25
 installation...................
20-in fender pile installation..              10              10              10              10              10
H-pile installation.............              25              10              30              15              10
Sheet pile installation.........              25              10              30              15              10
----------------------------------------------------------------------------------------------------------------
                                                       DTH
----------------------------------------------------------------------------------------------------------------
36-in steel permanent                      1,230              45           * 200           * 200              50
 installation...................
20-in steel fender pile                      265              10           * 200             145              15
 installation...................

[[Page 12652]]

 
H-pile installation.............             265              10           * 200             145              15
----------------------------------------------------------------------------------------------------------------
* Due to practicability of the applicant to shutdown and the difficulty of observing some species and low
  occurrence of some species in the project area, such as high frequency cetaceans or pinnipeds out to this
  distance, the shutdown zones were reduced and Level A harassment takes were requested during DTH and for
  impact pile driving of 36-in piles.

Soft Start

    The City 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 must be implemented at the start of each day's 
impact pile driving and at any time following cessation of impact pile 
driving for a period of 30 minutes or longer. Soft start is not 
required during vibratory pile driving and removal activities.

Vessels

    Vessels would adhere to the Alaska Humpback Whale Approach 
Regulations when transiting for project activities (see 50 CFR 216.18, 
223.214, and 224.103(b)). These regulations require that all vessels:
    [ssquf] Not approach within 91.44 m (100 yd) of a humpback whale, 
or cause a vessel or other object to approach within 91.44 m (100 yd) 
of a humpback whale;
    [ssquf] Not place vessel in the path of oncoming humpback whales 
causing them to surface within 91.44 m (100 yd) of vessel;
    [ssquf] Not disrupt the normal behavior or prior activity of a 
whale; and
    [ssquf] Operate at a slow, safe speed when near a humpback whale 
(safe speed is defined in regulation (see 33 CFR 83.06)).
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable impact on the 
affected species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 
significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, Section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth, requirements pertaining to 
the monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
    [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).
    [ssquf] Mitigation and monitoring effectiveness.

Monitoring Zones

    The City will establish and observe monitoring zones for Level B 
harassment as presented in Table 9. The monitoring zones for this 
project are 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 must 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 must be halted upon 
observation of either a species for which incidental take is not 
authorized or a species for which incidental take has been authorized 
but the authorized

[[Page 12653]]

number of takes has been met, entering or within the harassment zone.

PSO Monitoring Locations and Requirements

    The City must establish monitoring locations as described in the 
Marine Mammal Monitoring Plan. The City must monitor the project area 
to the extent possible based on the required number of PSOs, required 
monitoring locations, and environmental conditions. Monitoring would be 
conducted by PSOs from on land and from a vessel. 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. 
Three PSOs must be onsite during all in-water activities as follows: 
PSO 1 stationed at the pile site on the existing City Dock, PSO 2 
stationed on Halibut Island facing south and PSO 3 stationed on a 
vessel running a transect through southern portion of the project area 
in Port Frederick. 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-hr period (to reduce PSO 
fatigue).
    Monitoring of pile driving shall be conducted by qualified, NMFS-
approved PSOs. The City 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.
    [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.
    [ssquf] PSOs must be approved by NMFS prior to beginning any 
activity subject to this IHA.
    The City shall 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;
    [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; and
    [ssquf] Sufficient training, orientation, or experience with the 
construction operations to provide for personal safety during 
observations.

Notification of Intent To Commence Construction

    The City shall inform NMFS OPR and the NMFS Alaska Region Protected 
Resources Division one week prior to commencing construction 
activities.

Interim Monthly Reports

    During construction, the City will submit brief, monthly reports to 
the NMFS Alaska Region Protected Resources Division that summarize PSO 
observations and recorded takes. Monthly reporting will allow NMFS to 
track the amount of take (including any extrapolated takes), to allow 
reinitiation of consultation in a timely manner, if necessary. The 
monthly reports will be submitted by email to [email protected]. 
The reporting period for each monthly PSO report will be the entire 
calendar month, and reports will be submitted by close of business on 
the 10th day of the month following the end of the reporting period.

Final Report

    The City must submit a draft report 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 
[email protected] and [email protected]. 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.;

[[Page 12654]]

    [cir] Animal's closest point of approach and estimated time spent 
within the harassment zone.
    [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 City must report the 
incident to the Office of Protected Resources 
([email protected]), 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 City 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 City must 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'' 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 proposed mitigation section, shutdown zones that 
are larger than the Level A harassment zones will be implemented in the 
majority of construction days, which, in combination with the fact that 
the zones are so small to begin with, is expected to avoid the 
likelihood of Level A harassment for six of the nine species. For the 
other three species (harbor seals, Dall's and harbor porpoises), a 
small amount of Level A harassment has been conservatively proposed 
because the Level A harassment zones are larger than the proposed 
shutdown zones during impact pile driving of 36-in piles and during 
DTH. However, given the nature of the activities and sound source and 
the unlikelihood that animals would stay in the vicinity of the pile-
driving for long, any PTS incurred would be expected to be of a low 
degree and unlikely to have any effects on individual fitness.
    Exposures to elevated sound levels produced during pile driving 
activities may cause behavioral responses by an animal, but they are 
expected to be mild and temporary. Effects on individuals that are 
taken by Level B harassment, on the basis of reports in the literature 
as well as monitoring from other similar activities, will likely be 
limited to reactions such as increased swimming speeds, increased 
surfacing time, or decreased foraging (if such activity were occurring) 
(e.g., Thorson and Reyff, 2006; 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.
    To minimize noise during pile driving, the City will use pile caps 
(pile softening material). Much of the noise generated during pile 
installation comes from contact between the pile being driven and the 
steel template used to hold the pile in place. The contractor will use 
high-density polyethylene or ultra-high-molecular- weight polyethylene 
softening material on all templates to eliminate steel on steel noise 
generation.
    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 City will employ the use 
of three PSOs to ensure all monitoring and shutdown zones are properly 
observed.
    The HMIC Cargo Dock would likely not impact any marine mammal 
habitat since its proposed location is within an area that is currently 
used by large shipping vessels and in between two existing, heavily-
traveled docks, and within an active marine commercial and tourist 
area. There are no known pinniped haulouts or other biologically 
important areas for marine mammals near the action 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 Hoonah. 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

[[Page 12655]]

our preliminary determination that the impacts resulting from this 
activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
    [ssquf] No mortality is anticipated or authorized;
    [ssquf] Minimal impacts to marine mammal habitat/prey are expected;
    [ssquf] The action area is located and within an active marine 
commercial and tourist area;
    [ssquf] There are no rookeries, or other known areas or features of 
special significance for foraging or reproduction in the project area;
    [ssquf] Anticipated incidents of Level B harassment consist of, at 
worst, temporary modifications in behavior; and
    [ssquf] The required mitigation measures (i.e. shutdown zones) are 
expected to be effective in reducing the effects of the specified 
activity.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under 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.
    Seven of the nine marine mammal stocks proposed for take are 
approximately 11 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, 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 proposed take 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 proposed 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 proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    In September 2020, the Indigenous People's Council for Marine 
Mammals (IPCoMM), the Alaska Sea Otter and Steller Sea Lion Commission, 
Huna Totem Corporation, and the Hoonah Indian Association (HIA) were 
contacted to determine potential project impacts on local subsistence 
activities. No comments were received from IPCoMM or the Alaska Sea 
Otter and Steller Sea Lion Commission. On September 14, 2020, Huna 
Totem Corporation expressed support for the project and indicated that 
they do not anticipate any marine mammal or subsistence.
    The proposed 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; mitigation measures will be implemented to 
minimize disturbance of marine mammals in the project area; and the 
project will not result in significant changes to availability of 
subsistence resources.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there will 
not be an unmitigable adverse impact on subsistence uses from the 
City's proposed activities.
    Therefore, we believe there are no relevant subsistence uses of the 
affected marine mammal stocks or species implicated by this action. 
NMFS has preliminarily determined that the total taking of affected 
species or stocks would not have an unmitigable adverse impact on the 
availability of such species or stocks for taking for subsistence 
purposes.

Endangered Species Act (ESA)

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

[[Page 12656]]

determination regarding the proposed issuance of the authorization.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the City for conducting for the proposed pile driving 
and removal activities as well as DTH during construction of the Hoonah 
Marine Industrial Center Cargo Dock Project, Hoonah Alaska for one 
year, beginning March or April 2021, provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. A 
draft of the proposed IHA can be found at https://www.fisheries.noaa.gov/permit/incidental-take-authorizations-under-marine-mammal-protection-act.

Request for Public Comments

    We request comment on our analyses, the proposed authorization, and 
any other aspect of this notice of proposed IHA for the proposed pile 
driving and removal activities as well as DTH during construction of 
the Hoonah Marine Industrial Center Cargo Dock Project. We also request 
at this time, comments on the potential for Renewal of this proposed 
IHA as described in the paragraph below. Please include with your 
comments any supporting data or literature citations to help inform 
decisions on the request for this IHA or a subsequent Renewal IHA.
    On a case-by-case basis, NMFS may issue a one-time, 1-year Renewal 
IHA following notice to the public providing an additional 15 days for 
public comments when (1) up to another year of identical or nearly 
identical, or nearly identical, activities as described in the 
Description of Proposed Activities section of this notice is planned or 
(2) the activities as described in the Description of Proposed 
Activities section of this notice would not be completed by the time 
the IHA expires and a Renewal would allow for completion of the 
activities beyond that described in the Dates and Duration section of 
this notice, provided all of the following conditions are met:
    [ssquf] A request for renewal is received no later than 60 days 
prior to the needed Renewal IHA effective date (recognizing that the 
Renewal IHA expiration date cannot extend beyond one year from 
expiration of the initial IHA);
    [ssquf] The request for renewal must include the following:
    (1) An explanation that the activities to be conducted under the 
requested Renewal IHA are identical to the activities analyzed under 
the initial IHA, are a subset of the activities, or include changes so 
minor (e.g., reduction in pile size) that the changes do not affect the 
previous analyses, mitigation and monitoring requirements, or take 
estimates (with the exception of reducing the type or amount of take); 
and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
    Upon review of the request for Renewal, the status of the affected 
species or stocks, and any other pertinent information, NMFS determines 
that there are no more than minor changes in the activities, the 
mitigation and monitoring measures will remain the same and 
appropriate, and the findings in the initial IHA remain valid.

    Dated: February 26, 2021.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2021-04431 Filed 3-3-21; 8:45 am]
BILLING CODE 3510-22-P