Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to Construction at the City Dock and Ferry Terminal, in Tenakee Springs, Alaska, 12152-12178 [2018-05559]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 83, Number 54 (Tuesday, March 20, 2018)]
[Notices]
[Pages 12152-12178]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-05559]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XF830


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to Construction at the City Dock and 
Ferry Terminal, in Tenakee Springs, Alaska

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments.

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SUMMARY: NMFS has received a request from the Alaska Department of 
Transportations and Public Facilities (ADOT&PF) for authorization to 
take marine mammals incidental to conducting improvements at the 
Tenakee Springs city dock and ferry terminal, in Tenakee Springs, 
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 will consider public comments prior to 
making any final decision on the issuance of the requested MMPA 
authorization, and agency responses will be summarized in the final 
notice of our decision

DATES: Comments and information must be received no later than April 
19, 2018.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
1315 East-West Highway, Silver Spring, MD 20910 and electronic comments 
should be sent to [email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm 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: Jonathan Molineaux, 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: 
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of 
problems accessing these documents, please call the contact listed 
above.

SUPPLEMENTARY INFORMATION:

Background

    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 
authorization is provided to the public for review.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth.
    NMFS has defined ``negligible impact'' in 50 CFR 216.103 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.
    The MMPA states that the term ``take'' means to harass, hunt, 
capture, kill or

[[Page 12153]]

attempt to harass, hunt, capture, or kill any marine mammal.
    Except with respect to certain activities not pertinent here, 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).

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to potential impacts 
on the human environment.
    This action is consistent with categories of activities identified 
in CE B4 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 23, 2017, NMFS received a request from ADOT&PF for an 
IHA to take marine mammals incidental to conducting improvements at the 
Tenakee Springs city dock and ferry terminal, in Tenakee Springs, 
Alaska. The application was considered adequate and complete on January 
30, 2018. ADOT&PF's request is for take of seven species of marine 
mammals by Level B harassment only. Neither ADOT&PF nor NMFS expect 
mortality to result from this activity and, therefore, an IHA is 
appropriate. The planned activity is not expected to exceed one year, 
hence, we do not expect subsequent MMPA IHAs to be issued for this 
particular activity.

Description of Proposed Activity

Overview

    The ADOT&PF plans to make improvements to the Tenakee Springs Ferry 
Terminal located in Tenakee Springs, Alaska, on Chichigof Island in 
southeast Alaska (Figure 1-1 of the application). The facility is a 
multi-function dock and active ferry terminal located in the center of 
town (see Figure 1-2 and Figure 1-3 in application). The project's 
proposed activities that have the potential to take marine mammals 
include vibratory and impact pile driving, drilling operations for pile 
installation (down-hole hammer), and vibratory pile removal.
    The purpose of the project is to replace the existing, aging 
mooring and transfer structures nearing the end of their operational 
life due to corrosion and wear with modern facilities that provide 
improved operations for Alaska Marine Highway System (AMHS) ferry 
vessels, as well as freight and fueling operators, servicing the 
community of Tenakee Springs. Planned improvements include the 
installation of new shore side facilities and marine structures and the 
renovation of existing structures. This will accommodate cargo and 
baggage handling, vessel mooring, passenger and vehicle access 
gangways, and re-establish existing electrical and fuel systems. 
Improvements will enhance public safety and security.

Dates and Duration

    In-water project construction activities will begin no sooner than 
June 1, 2019. Pile installation and removal is expected to be completed 
in 93 working days within a 4-month window beginning sometime after 
June 1, 2019. Pile installation will be intermittent and staggered 
depending on weather, construction and mechanical delays, marine mammal 
shutdowns, and other potential delays and logistical constraints. Given 
the possibility of schedule delays and other unforeseen circumstances, 
an IHA is being requested for a full year, from June 1, 2019 through 
May 31, 2020.
    Specific Geographic Region--The Tenakee Springs Ferry Terminal is 
located in the City of Tenakee Springs, Alaska, at 57[deg]46'45.6'' N, 
135[deg]13'09.1'' W, on Chichagof Island, on the north shore of Tenakee 
Inlet, in southeast Alaska (Figure 1-1 and Figure 1-2). Tenakee Springs 
is part of the Hoonah-Angoon Census Area. In 2016, there were an 
estimated 130 residents of Tenakee Springs. It is the second largest 
city on Chichagof Island.
    The Tenakee Springs Ferry Terminal is an active ferry terminal 
located in Tenakee Inlet and provides the primary access point to the 
city of Tenakee Springs. Improvements and new construction will take 
place in the same location as the existing dock. A sea plane float is 
located immediately east of the ferry terminal and a small boat harbor 
is located approximately 700 meters east of the terminal (see Figure 1-
2 of application).
    The town of Tenakee Springs is located on the north side of Tenakee 
Inlet, about 16 kilometers (km) (9.9 miles) west of where the Inlet 
opens to Chatham Strait. Tenakee Inlet is a long, narrow fjord with 
steep, rocky sides interspersed with extensive mudflats and intertidal 
zones. Water depths consistently reach 900 to 1,100 meters (2,950 to 
3,600 feet) in the center of the Inlet, with at least one location 
deeper than 1,280 meters (4,200 feet). The shoreline is complex and 
meandering, interspersed with numerous coves, islands, and rocky 
outcroppings. Numerous rivers and creeks feed into the Inlet, 
contributing to the highly productive marine environment.
    The Inlet supports abundant marine resources, including salmon, 
herring, crab, and shrimp. Marine mammals use the Inlet regularly, 
attracted to the rich foraging grounds. Humpback whales are seen bubble 
feeding in summer, and harbor seals haul out on rocky islets around the 
area.
    Baseline background (ambient) sound levels in Tenakee Inlet are 
unknown. The areas around the existing ferry terminal are frequented by 
ferries, fishing vessels, and tenders; barges and tugboats; float 
planes; and other commercial and recreational vessels that use the 
small-boat harbor, city dock, and other commercial facilities.

Detailed Description of Specific Activity

    The proposed action includes pile installation and removal for the 
various aspects of the project (see Figure 1-4 of application). There 
will be no dredging or removal of substrate, nor any deposition of fill 
or armor rock associated with the project. Above-water construction 
will consist of the installation of concrete platform decking panels, 
utility lines, and a fuel building. The new facility will continue to 
serve as the AMHS ferry terminal and will support shipping and 
receiving of commercial and service-industry goods. Given the lack of 
road access to Tenakee Springs, the ferry terminal is an essential 
component of infrastructure, providing critical access between Tenakee 
Springs and the rest of the region. Planned improvements will not add 
any additional berths for vessels,

[[Page 12154]]

and the existing capacity of the facilities will remain the same.
    The project includes the following components:
     Removal and replacement of an existing 12-foot by 240-foot 
approach dock decking and installation of additional steel pipe support 
piles;
     Removal of an existing city storage and fuel building and 
pile-supported dock and timber fender piles;
     Removal of an existing steel gangway float, platform, and 
associated steel pipe piles; and
     Removal of three, three-pile berthing and mooring 
dolphins.
    The project will also include the installation of:
     A 50-foot by 70-foot pile-supported ferry staging dock;
     A 50-foot by 60-foot pile-supported dock with new fuel 
building and associated dock mounted fender system;
     An 11-foot by 90-foot steel transfer bridge and pile-
supported abutment;
     A steel bridge support float with adjustable intermediate 
ramp and apron with two, four-pile float restraint dolphins;
     Four, four-pile berthing dolphins; and
     A ferry access skiff float and associated steel pipe pile 
restraints.

Removal of Old Piles

    The project will require the removal of approximately 84 piles of 
varying sizes and materials (Table 1-1). Not all existing structures 
and piles will be removed (Figure 1-4). It is anticipated that, when 
possible, existing piles will be extracted by directly lifting them 
with a crane. A vibratory hammer will be used only if necessary to 
extract piles that cannot be directly lifted. Removal of each old pile 
is estimated to require no more than 15 minutes of vibratory hammer 
use.

                                          Table 1--Pile Details and Estimated Effort Required for Pile Removal
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                                                                                                           Vibratory   Estimated   Number of
                                                                                   Number of     Total     duration      total     piles per    Days of
           Pile diameters & material                    Project component            piles     number of   per pile    number of      day       removal
                                                                                                 piles       (min)       hours      (range)
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12.75-inch Steel Piles........................  Approach Dock...................           2           2          15         0.5           2           1
14-inch Timber Piles..........................  City Dock Fender Piles..........          33          42          15        10.5        5-10           9
                                                City Storage Building Dock......           9
14-inch Steel Piles...........................  City Dock.......................          14          26          15         6.5        5-10           6
                                                Berthing Dolphin Fenders........          12
16-inch Steel Piles...........................  Berthing Dolphins...............           9           9          15        2.25        5-10           2
18-inch Steel Piles...........................  Steel Float.....................           5           5          15        1.25           5           1
                                                                                 -----------------------------------------------------------------------
    Totals....................................  ................................  ..........          84  ..........          21  ..........          19
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Installation of New Piles

    The Project will require the installation of 121 piles of varying 
sizes and materials (see Table 2). Tension anchors will be installed in 
86 of the 121 total piles. Initial installation of steel piles through 
the sediment layer may be done using vibratory methods for up to 15 
minutes per pile. If the sediment layer is very thin, instead of 
vibratory methods, a few strikes from an impact hammer may be used to 
seat some steel piles into the weathered bedrock before drilling 
begins. It is possible that only an impact hammer and drilling will be 
used for some piles, and only a vibratory hammer and drilling will be 
used for other piles, depending on sediment conditions and as decided 
by the construction contractor. Following initial pile installation, 
the mud accumulation on the inside of the pile will be augured out (or 
cleaned through another method), as necessary. Next, a hole (rock 
socket) will be drilled in the underlying bedrock by using a down-hole 
hammer (see Figure 1-5 of IHA application). A down-hole hammer is a 
drill bit that drills through the bedrock and a pulse mechanism that 
functions at the bottom of the hole, using a pulsing bit to break up 
the rock to allow removal of the fragments and insertion of the pile. 
The head extends so that the drilling takes place below the pile. Drill 
cuttings are expelled from the top of the pile as dust or mud and 
allowed to settle at the base of the pile. It is estimated that 
drilling piles through the layered bedrock will take about 2-3 hours 
per pile.
    Drilling will create a 10-foot-deep bedrock socket that holds the 
pile in place. The bedrock will attenuate noise production from 
drilling and reduce noise propagation into the water column. 
Additionally, the casing used during drilling acts like a cofferdam and 
will block noise, further reducing noise levels (82 Federal Register 
[FR] 34632; proposed IHA for the Gary Paxton Industrial Park Dock 
Modification Project in Sitka, Alaska). However, noise levels from 
drilling the bedrock socket to support piles will likely exceed the 
120-decibel (dB) root mean square (rms) threshold for Level B 
harassment from continuous noise (Section 6.2.2) during at least a 
portion of the drilling.
    If necessary after drilling, no more than 30 blows from an impact 
hammer will be used to confirm that piles are set into bedrock 
(proofed). Proofing will require approximately 5-10 minutes per pile.
    Tension anchors will be installed on 86 of the 121 steel piles. In 
general, the farthest seaward piles will utilize tension anchors. To 
anchor each pile following pile installation, a 10-inch casing will be 
inserted into the center of the pile and an 8-inch rock anchor drill 
will be lowered into the casing and used to drill into bedrock. Rock 
fragments will be removed through the top of the casing as dust or mud. 
Finally, the drill and casing will be removed, and an anchor attached 
by an anchor rod will be inserted into the hole. The hole will be 
filled with grout, which will harden, thereby encapsulating the anchor 
in the borehole and securing the pile and anchor to bedrock. Once 
installed, tension anchors are tightened, applying tension to the pile 
to prevent movement within the rock socket. Eight of the tension 
anchors will be passive, which means they will not be tightened. This 
will provide the pile with a small amount of play, which will allow the 
pile to move until it meets the extent of the tension anchor.
    Drilling for anchors takes place below the 10-foot-deep bedrock 
socket that holds the pile in place, and the bedrock serves to 
attenuate noise production from drilling activity and reduce noise 
propagation into the water column. Additionally, the casing acts like a 
cofferdam and will block noise; therefore, anchor drilling will result 
in low levels of in-water noise that do not

[[Page 12155]]

approach injury or harassment levels for marine mammals (82 FR 34632; 
proposed IHA for the Gary Paxton Industrial Park Dock Modification 
Project in Sitka, Alaska). No take for harassment of marine mammals 
from anchor drilling is requested.
    Installation of timber piles will use only an impact hammer, and 
will require approximately 75 strikes per pile, or approximately 20-30 
minutes to install each pile.
    Pile installation activities will occur in waters from zero to 36 
feet (0 to 11 meters) deep within or immediately adjacent to the 
existing dock footprint. It is anticipated that an ICE model vibratory 
driver or equivalent hammer and a Delmag D30 or Vulcan impact hammer, 
or equivalent hammer will be used to install the piles.

                                        Table 2--Pile Details and Estimated Effort Required for Pile Installation
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                                                                                             Drilling
                                                                       Total     Vibratory   duration     Impact     Estimated   Number of
    Pile diameters & material       Project component    Number of   number of   duration   per pile a    strikes      total     piles per     Days of
                                                           piles       piles     per pile      (min)     per pile    number of      day     installation
                                                                                   (min)                               hours      (range)
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24-inch Steel Piles a............  City Dock..........          22          46          15         120          30         107         2-3           23
                                   Ferry Staging Dock.          20
                                   Transfer Bridge               4
                                    Abutment.
30-inch Steel Piles a............  Float Restraints              4          20          15         180          30          67         2-3           10
                                    (Vertical).
                                   Berthing Dolphins             8
                                    (Battered).
                                   Berthing Dolphins             8
                                    (Vertical).
20-inch Steel Piles a............  Float Restraints              4           4          15         180          30          13         2-3            2
                                    (Battered).
18-inch Steel Piles a............  Approach Dock......           8          21          15         120          30          49         2-3           11
                                   Berthing Fenders...          10
                                   Skiff Float........           3
14-inch Timber Piles.............  Boat Moorage                 30          30          NA          NA          75          10        5-10            6
                                    Fenders.
8-inch Tension Anchors...........  Tension Anchors....          78        b 86          NA          60          NA          86         4-8           22
                                   Passive Tensions              8
                                    Anchors.
                                                       -------------------------------------------------------------------------------------------------
    Totals.......................  ...................  ..........         121  ..........  ..........  ..........         332  ..........           74
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a All 91 steel piles will require drilling.
b Tension anchors will be installed in a subset of piles and therefore are not included in the total number of piles.

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; www.nmfs.noaa.gov/pr/sars/) and more general information about these species (e.g., physical 
and behavioral descriptions) may be found on NMFS's website 
(www.nmfs.noaa.gov/pr/species/mammals/).
    Table 3 lists all species with expected potential for occurrence in 
Tenakee Springs, Alaska and summarizes information related to the 
population or stock, including regulatory status under the MMPA and 
Endangered Species Act (ESA) and potential biological removal (PBR), 
where known. For taxonomy, we follow Committee on Taxonomy (2016). PBR 
is defined by the MMPA as the maximum number of animals, not including 
natural mortalities, that may be removed from a marine mammal stock 
while allowing that stock to reach or maintain its optimum sustainable 
population (as described in NMFS's SARs). While no mortality is 
anticipated or authorized here, PBR and annual serious injury and 
mortality from anthropogenic sources are included here as gross 
indicators of the status of the species and other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS'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. Alaska SARs (Muto 2017a). All values presented in Table 3 
are the most recent available at the time of publication and are 
available in the 2016 SARs (Muto, 2017a), Towers et al., 2015 (solely 
for northern resident killer whales), and draft 2017 SARs (Muto 2017b).
    Two cetacean species have ranges near Tenakee Inlet but are 
unlikely to occur in the project area: The Pacific white-sided dolphin 
(Lagenorhynchus obliquidens) and gray whale (Eschrichtius robustus). 
The ranges of both the Pacific white-sided dolphin and gray whale are 
suggested to overlap with Tenakee Inlet (Muto, 2017a), but no sightings 
have been documented in the project area (Dahlheim et al. 2009).

                               Table 3--Marine Mammals That Could Occur in the Project Area During the Specified Activity
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                                                                                                            Stock abundance Nbest,
                                                                                         ESA/ MMPA status;     (CV, N min, most                Annual M/
             Common name                  Scientific name             MMPA stock         strategic (Y/N) 1     recent abundance        PBR        SI 3
                                                                                                                   survey) 2
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
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Family Balaenidae:
    Humpback whale..................  Megaptera novaeangliae.  Central North Pacific..  E, D,Y              10,103 (0.3, 7,890,            83         21
                                                                                                             2006).
    Minke whale.....................  Balaenoptera             Alaska.................  -, N                N.A...................       N.A.       N.A.
                                       acutorostrata.
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[[Page 12156]]

 
                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
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Family Delphinidae:
    Killer whale....................  Orcinus orca...........  Alaska Resident........  -, N                2,347 (N.A., 2,347,          23.4          1
                                                                                                             2012) 4.
                                                               West Coast Transient...  -, N                243 (N/A, 243, 2009) 4        2.4          1
                                                               Northern Resident......  -, N                290 (N/A, 290, 2014) 6       1.96          0
Family Phocoenidae:
    Harbor porpoise.................  Phocoena phocoena......  Southeast Alaska.......  -, Y                975 (0.10, 896, 2012)       5 8.9       5 34
                                                                                                             5.
    Dall's porpoise.................  Phocoenoides dalli.....  Alaska.................  -, N                83,400................       N.A.         38
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                                                         Order Carnivora--Superfamily Pinnipedia
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Family Otariidae (eared seals and
 sea lions):
    Steller sea lion................  Eumatopia jubatus......  Western U.S.\7\........  E, D; Y             50,983 (N.A., 50,983,         320        241
                                                                                                             2016).
                                                               Eastern U.S............  -, D, Y             41,638 (N/A, 41,638,        2,498        108
                                                                                                             2015).
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Family Phocidae (earless seals):
    Harbor seal.....................  Phoca vitulina           Glacier Bay/Icy Strait.  -, N                7,210 (N.A.; 5,647;           169        104
                                       richardii.                                                            2011).
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\1\ 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; N min is the minimum estimate of
  stock abundance. In some cases, CV is not applicable (N/A).
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike).
\4\ N is based on counts of individual animals identified from photo-identification catalogs.
\5\ In the SAR for harbor porpoise (NMFS 2017), NMFS identified population estimates and PBR for porpoises within inland Southeast Alaska waters (these
  abundance estimates have not been corrected for g(0); therefore, they are likely conservative). The calculated PBR is considered unreliable for the
  entire stock because it is based on estimates from surveys of only a portion (the inside waters of Southeast Alaska) of the range of this stock as
  currently designated. The Annual M/SI is for the entire stock, including coastal waters.
\6\ Abundance estimates obtained from Towers et al 2015.
\7\ Abundance, PBR, and Annual M/SI derived from draft 2017 SARs (Muto2017b).

    All species that could potentially occur in the proposed survey 
areas are included in Table 3. As described below, all seven species 
(with nine managed stocks) temporally and spatially co-occur with the 
activity to the degree that take is reasonably likely to occur, and we 
have proposed authorizing it. In addition, sea otters may be found in 
Tenakee Springs. However, sea otters are managed by the U.S. Fish and 
Wildlife Service and are not considered further in this document.

Pinnipeds in the Activity Area

Steller Sea Lion
    The Steller sea lion is the largest of the eared seals, ranging 
along the North Pacific Rim from northern Japan to California, with 
centers of abundance and distribution in the Gulf of Alaska and 
Aleutian Islands. Steller sea lions were listed as threatened range-
wide under the ESA on November 26, 1990 (55 FR 49204). Subsequently, 
NMFS published a final rule designating critical habitat for the 
species as a 20 nautical mile buffer around all major haulouts and 
rookeries, as well as associated terrestrial, air and aquatic zones, 
and three large offshore foraging areas (58 FR 45269; August 27, 1993). 
In 1997, NMFS reclassified Steller sea lions as two distinct population 
segments (DPS) based on genetic studies and other information (62 FR 
24345; May 5, 1997). Steller sea lion populations that primarily occur 
west of 144[deg] W (Cape Suckling, Alaska) comprise the western DPS 
(wDPS), while all others comprise the eastern DPS (eDPS); however, 
there is regular movement of both DPSs across this boundary (Jemison et 
al., 2013). Upon this reclassification, the wDPS became listed as 
endangered while the eDPS remained as threatened (62 FR 24345; May 5, 
1997) and in November 2013, the eDPS was delisted (78 FR 66140). No 
critical habitat for this species is designated in Southeast Alaska.
    Steller sea lions are known to occur within the project area; 
however, systematic counts or surveys have not been completed 
throughout Tenakee Inlet. Therefore, the best information regarding sea 
lion abundance and distribution comes from anecdotal reports from local 
residents and extrapolations from nearby haulouts that have been 
regularly monitored.
    Anecdotal reports indicate that sea lions are generally present 
only in the fall and winter. Reports of these anecdotal observations 
also suggest that as many as 10-20 may swim by on a winter day, 
although most feed at night when their herring prey tend to be near the 
water's surface (Wheeler, K., pers. comm.).
    Steller sea lions use terrestrial haulout sites to rest and take 
refuge. They also gather on well-defined, traditionally used rookeries 
to pup and breed. These habitats are typically gravel, rocky, or sand 
beaches; ledges; or rocky reefs. The closest Steller sea lion haulout 
to the project area is the Tenakee Cannery Point haulout, which is 
approximately 8.9 km (4.8 nautical miles) east of the project site 
(Fritz et al., 2016c; see Figure 4-1 of application). Recent summer 
counts have not recorded any Steller sea lions at this haulout, and 
historical counts between April and September have not exceeded 12 
individuals during any survey (Fritz et al., 2016b). This haulout 
appears to be most active between October and March (Figure 4-2), which 
is consistent with anecdotal reports of sea lion abundance in the 
project area (Rasanen, L., pers. comm.; Wheeler, K., pers. comm.). Non-
pup counts conducted between October and March from 2001 to 2004 
averaged 106 individuals and ranged from 16 to 251 (Fritz et al., 
2016b). Pups have not been counted at this haulout (Fritz et al., 
2016a). In addition to those counted at

[[Page 12157]]

the haulouts, as many as a few hundred more sea lions occur throughout 
Tenakee Inlet in small hunting groups (Rasanen, L., pers. comm.). The 
Point Marsden and Emmons haulouts are also located within 20 nautical 
miles of Tenakee Springs, but it is unlikely that individuals from 
those haulouts regularly inhabit Tenakee Inlet. Experts with the Alaska 
Fisheries Science Center of NMFS estimate that roughly 17.8 percent of 
the Steller sea lions at the Tenakee Cannery Point haulout are members 
of the western DPS (L. Fritz, pers. comm; L. Fritz, unpublished data) 
while the rest (82.2 percent) are from the eastern DPS. Steller sea 
lions are included in Alaska subsistence harvests. Since subsistence 
harvest surveys began in 1992, the number of households hunting and 
harvesting sea lions has remained relatively constant at low levels 
(Wolf et al., 2013).
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, with local movements 
associated with such factors as tides, weather, season, food 
availability, and reproduction (Muto, 2017a).
    Harbor seals in Alaska are partitioned into 12 separate stocks 
based largely on genetic structure: (1) The Aleutian Islands stock, (2) 
the Pribilof Islands stock, (3) the Bristol Bay stock, (4) the North 
Kodiak stock, (5) the South Kodiak stock, (6) the Prince William Sound 
stock, (7) the Cook Inlet/Shelikof stock, (8) the Glacier Bay/Icy 
Strait stock, (9) the Lynn Canal/Stephens Passage stock, (10) the 
Sitka/Chatham stock, (11) the Dixon/Cape Decision stock, and (12) the 
Clarence Strait stock. Only the Glacier Bay/Icy Strait stock is 
considered in this proposed IHA. The range of this stock includes Cape 
Fairweather southeast to Column Point, extending inland to Glacier Bay, 
Icy Strait, and from Hanus Reef south to Tenakee Inlet (Muto, 2017a).
    Survey data from 2003 through 2011 indicate that there are eight 
harbor seal haulouts in Tenakee Inlet and a number of others nearby in 
Chatham Strait and Freshwater Bay (Figure 4-3). The nearest haulout to 
the project site is located on Tenakee Reef, near Tenakee Reef Light (a 
navigational and warning light for vessels), approximately 1 km south 
of the ferry terminal. Anecdotal observations indicate that up to 200 
harbor seals may haul out on the rocks at and around the Tenakee Reef 
Light at any time of year (Rasanen, L., pers. comm.). Two additional 
harbor seal haulouts are located approximately 5.2 and 10.0 km from the 
ferry terminal, on Strawberry Island and in Crab Bay, respectively.
    Aerial haulout surveys conducted in August 2011 divide Tenakee 
Inlet into four survey units. The survey unit along the north shore of 
the Inlet, including the project site, had a population estimate of 61 
individuals. Other survey units in Tenakee Inlet had between 1 and 64 
individuals. This information comes from a single year of surveys, and 
standard errors on these estimates are very high; therefore, confidence 
is low (London et al., 2015). Researchers estimate that the total 
abundance in Tenakee Inlet was approximately 259 seals in 2011, 
including about 170 in the upper inlet and approximately 89 near the 
mouth (London, J., pers. comm.).
    Because harbor seals are non-migratory, we do not suspect that 
abundance fluctuates seasonally, but distribution throughout Tenakee 
Inlet and Chatham Strait likely fluctuates drastically based on 
numerous environmental factors.

Cetaceans in the Action Area

Humpback Whale
    The humpback whale is distributed worldwide in all ocean basins. In 
winter, most humpback whales occur in the subtropical and tropical 
waters of the Northern and Southern Hemispheres, and migrate to high 
latitudes in the summer to feed. The historic summer feeding range of 
humpback whales in the North Pacific encompassed coastal and inland 
waters around the Pacific Rim from Point Conception, California, north 
to the Gulf of Alaska and the Bering Sea, and west along the Aleutian 
Islands to the Kamchatka Peninsula and into the Sea of Okhotsk and 
north of the Bering Strait (Johnson and Wolman 1984).
    Under the MMPA, there are three stocks of humpback whales in the 
North Pacific: (1) The California/Oregon/Washington and Mexico stock, 
consisting of winter/spring populations in coastal Central America and 
coastal Mexico which migrate to the coast of California to southern 
British Columbia in summer/fall; (2) the central North Pacific stock, 
consisting of winter/spring populations of the Hawaiian Islands which 
migrate primarily to northern British Columbia/Southeast Alaska, the 
Gulf of Alaska, and the Bering Sea/Aleutian Islands; and (3) the 
western North Pacific stock, consisting of winter/spring populations 
off Asia which migrate primarily to Russia and the Bering Sea/Aleutian 
Islands. The central North Pacific stock is the only stock that is 
found near the project activities.
    On September 8, 2016, NMFS published a final rule dividing the 
globally listed endangered species into 14 DPSs, removing the worldwide 
species-level listing, and in its place listing four DPSs as endangered 
and one DPS as threatened (81 FR 62259; effective October 11, 2016). 
Two DPSs (Hawaii and Mexico) are potentially present within the action 
area. The Hawaii DPS is not listed and the Mexico DPS is listed as 
threatened under the ESA. The Hawaii DPS is estimated to contain 11,398 
animals where the Mexico DPS is estimated to contain 3,264 animals.
    Within the action area, humpback whales are seen most frequently 
from September through February although sightings may extend into 
April (Straley and Pendell 2017). Humpback whales are found throughout 
southeast Alaska in a variety of marine environments, including open-
ocean, near-shore waters, and areas with strong tidal currents 
(Dahlheim et al., 2009). Most humpback whales are migratory and spend 
winters in the breeding grounds off either Hawaii or Mexico. Humpback 
whales generally arrive in southeast Alaska in March and return to 
their wintering grounds in November. Some humpback whales depart late 
or arrive early to feeding grounds, and therefore the species occurs in 
southeast Alaska year-round (Straley 1990). Across the region, there 
have been no recent estimates of humpback whale density, and there have 
been no systematic surveys of humpback whales in or near the project 
area. Marine mammal experts in the region have indicated that there are 
as many as 12 humpbacks present in Tenakee Inlet from spring through 
fall. During the winter, they are less common, but are regularly 
present (S. Lewis and M. Dahlheim, pers. comm.).
Minke Whale
    Minke whales are found throughout the northern hemisphere in polar, 
temperate, and tropical waters. In the North Pacific, minke whales 
occur from the Bering and Chukchi seas south to near the Equator 
(Leatherwood et al., 1982). In Alaska, the minke whale diet consists 
primarily of euphausiids and walleye pollock. Minke whales are

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generally found in shallow, coastal waters within 200 meters of shore 
(Zerbini et al., 2006) and are usually solitary or in small groups of 2 
to 3. Rarely, loose aggregations of up to 400 animals have been 
associated with feeding areas in arctic latitudes. In Alaska, seasonal 
movements are associated with feeding areas that are generally located 
at the edge of the pack ice (NMFS 2014). Surveys in southeast Alaska 
have consistently identified individuals throughout inland waters in 
low numbers (Dahlheim et al., 2009).
    Little is known about minke whale abundance and distribution in the 
project area as there have been no systematic studies conducted on the 
species in or near Tenakee Inlet. Surveys throughout southeast Alaska 
between 1991 and 2007 recorded minke whales infrequently, but noted a 
wide variety of habitat types used throughout all inland waters and 
little seasonal variation. During these surveys, the observation 
nearest to Tenakee Springs was in Chatham Strait, approximately 10 
miles south of the mouth of Tenakee Inlet. Concentrations of minke 
whales were observed near the entrance to Glacier Bay. Most minke 
whales observed during the surveys were individual animals (Dahlheim et 
al., 2009).
Killer Whale
    Killer whales have been observed in all the world's oceans, but the 
highest densities occur in colder and more productive waters found at 
high latitudes (NMFS 2016a). Killer whales occur along the entire 
Alaska coast, in British Columbia and Washington inland waterways, and 
along the outer coasts of Washington, Oregon, and California (Muto et 
al., 2017a).
    Based on data regarding association patterns, acoustics, movements, 
and genetic differences, eight killer whale stocks are now recognized 
within the Pacific U.S. Exclusive Economic Zone. This proposed IHA 
considers only the Alaska resident stock, northern resident and the 
west coast transient, all other stocks occur outside the geographic 
area under consideration (Muto et al., 2017a).
    The Alaska Resident stock occurs from southeastern Alaska to the 
Aleutian Islands and Bering Sea. Photo-identification studies between 
2005 and 2009 identified 2,347 individuals in this stock, including 
approximately 121 in southeast Alaska (Muto et al., 2017a). The West 
Coast transient stock occurs from California north through southeast 
Alaska. Between 1975 and 2012, surveys identified 521 individual West 
Coast transient killer whales. Dahlheim et al. (2009) noted a 5.2 
percent annual decline in transient killer whales observed in southeast 
Alaska. The northern resident stock occurs from Washington State 
through part of southeastern Alaska. The trend for the Northern 
resident stock is an increasing population with an average of 2.1 
percent annual increase over a 36-year period.
    Surveys between 1991 and 2007 encountered resident killer whales 
during all seasons throughout southeast Alaska. Both residents and 
transients were common in a variety of habitats and all major 
waterways, including protected bays and inlets. During this study, 
strong seasonal variation in abundance or distribution of killer whales 
was not present, but there was substantial variability between years 
(Dahlheim et al., 2009). In Tenakee Inlet, systematic surveys of killer 
whales have not been completed. Nevertheless, local marine mammal 
experts estimate that approximately one killer whale pod passes by 
Tenakee Springs each month (Lewis, S., pers. comm.). It is not known 
whether these are resident or transient whales.
Harbor Porpoise
    The harbor porpoise inhabits temporal, subarctic, and arctic 
waters. In the eastern North Pacific, harbor porpoises range from Point 
Barrow, Alaska, to Point Conception, California. Harbor porpoise 
primarily frequent coastal waters and occur most frequently in waters 
less than 100 m deep (Hobbs and Waite 2010). They may occasionally be 
found in deeper offshore waters.
    In Alaska, harbor porpoises are currently divided into three 
stocks, based primarily on geography: (1) The Southeast Alaska stock--
occurring from the northern border of British Columbia to Cape 
Suckling, Alaska, (2) the Gulf of Alaska stock--occurring from Cape 
Suckling to Unimak Pass, and (3) the Bering Sea stock--occurring 
throughout the Aleutian Islands and all waters north of Unimak Pass. 
Only the Southeast Alaska stock is considered in this proposed IHA 
because the other stocks are not found in the geographic area under 
consideration. The 2016 SAR for this stock further delineated 
population estimates (Muto et al., 2017a). The total estimated annual 
level of human-caused mortality and serious injury for Southeast Alaska 
harbor porpoise (n= 34) exceeds the calculated PBR of 8.9 porpoises. 
However, the calculated PBR is considered unreliable for the entire 
stock because it is based on estimates from surveys of only a portion 
(the inside 7of Southeast Alaska) of the range of this stock as 
currently designated. Because the total stock abundance estimates are 
more than eight years old (with the exception of the 2010-2012 
abundance estimates provided for the inland waters of Southeast 
Alaska), and the frequency of incidental mortality and serious injury 
in U.S. commercial fisheries throughout Southeast Alaska is not known, 
the Southeast Alaska stock of harbor porpoise is classified as a 
strategic stock. Population trends and status of this stock relative to 
its Optimum Sustainable Population are currently unknown.
    There are no subsistence use of this species; however, as noted 
above, entanglement in fishing gear contributes to human-caused 
mortality and serious injury. Muto et al. (2017a) also reports harbor 
porpoise are vulnerable to physical modifications of nearshore habitats 
resulting from urban and industrial development (including waste 
management and nonpoint source runoff) and activities such as 
construction of docks and other over-water structures, filling of 
shallow areas, dredging, and noise (Linnenschmidt et al., 2013).
    Information on harbor porpoise abundance and distribution in 
Tenakee Inlet has not been systematically collected. Anecdotal 
observations from marine mammal researchers indicate that harbor 
porpoise are seen a few times per month in groups of 3 to 5 
individuals, but there is no seasonal trend to these observations 
(Dahlheim, M., pers. comm.).
Dall's Porpoise
    Dall's porpoise are widely distributed across the entire North 
Pacific Ocean. They are found over the continental shelf adjacent to 
the slope and over deep (2,500+ meters) oceanic waters (Hall 
1979). They have been sighted throughout the North Pacific as far north 
as 65[deg] N (Buckland et al., 1993) and as far south as 28[deg] N in 
the eastern North Pacific (Leatherwood and Fielding 1974). The only 
apparent distribution gaps in Alaska waters are upper Cook Inlet and 
the shallow eastern flats of the Bering Sea. Throughout most of the 
eastern North Pacific they are present during all months of the year, 
although there may be seasonal onshore-offshore movements along the 
west coast of the continental U.S. (Loeb 1972, Leatherwood and Fielding 
1974) and winter movements of populations out of areas with ice such as 
Prince William Sound (Hall 1979).
    There currently is no information on the presence or abundance of 
Dall's porpoises in Tenakee Inlet. Local

[[Page 12159]]

marine mammal experts indicate that the species is rarely seen near 
Tenakee Springs (Lewis, S., pers. comm.). Dall's porpoises likely occur 
more often in the deeper waters of Chatham Strait, although waters more 
than 600 feet (182 meters) deep are found within the central portion of 
Tenakee Inlet between Tenakee Springs and Chatham Strait (Figure 4-4). 
Average pod size in southeast Alaska ranges from three to six 
individuals (Dahlheim et al., 2009). Dall's porpoise commonly 
``bowride,'' or ride the wake created by large, relatively fast-moving 
vessels. It is possible that Dall's porpoises may bowride alongside a 
vessel into the project area, but we would not expect individuals to 
stay for long periods or congregate in the project area, nor to venture 
farther up Tenakee Inlet due to shallow water depths.

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 (2016) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibels (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. The functional groups and 
the associated frequencies are indicated below in Table 4 (note that 
these frequency ranges correspond to the range for the composite group, 
with the entire range not necessarily reflecting the capabilities of 
every species within that group):

   Table 4--Marine Mammal Hearing Groups and Their Generalized Hearing
                                  Range
------------------------------------------------------------------------
               Hearing group                 Generalized hearing range *
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen        7 Hz to 35 kHz (Best Hearing
 whales).                                    Range: 100 Hz to 8 kHz).
Mid-frequency (MF) cetaceans (dolphins,     150 Hz to 160 kHz (Best
 toothed whales, beaked whales, bottlenose   Hearing Range: 10 kHz to
 whales).                                    100 kHz).
High-frequency (HF) cetaceans (true         275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus cruciger
 and L. australis).
Phocid pinnipeds (PW) (underwater) (true    50 Hz to 86 kHz (Best
 seals).                                     Hearing Range: 1 kHz to 50
                                             kHz).
Otariid pinnipeds (OW) (underwater) (sea    60 Hz to 39 kHz (Best
 lions and fur seals).                       Hearing Range: 2 kHz to 48
                                             kHz).
------------------------------------------------------------------------
* 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 (2016) for a review of available information. 
As previously discussed, seven marine mammal species (five cetacean and 
two pinniped (one otariid and one phocid) species) have the reasonable 
potential to co-occur with the proposed survey activities. Please refer 
to Table 3. Of the cetacean species that may be present, two are 
classified as low-frequency cetaceans (i.e., all mysticete species), 
one is classified as a mid-frequency cetaceans (i.e., killer whale), 
and two are classified as high-frequency cetaceans (i.e., harbor 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 by Incidental Harassment'' section, and the ``Proposed 
Mitigation'' section, to draw conclusions regarding the likely impacts 
of these activities on the reproductive success or survivorship of 
individuals and how those impacts on individuals are likely to impact 
marine mammal species or stocks.

Description of Sound Sources

    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 of a sound wave; lower frequency sounds have 
longer wavelengths than higher frequency sounds. Amplitude is the 
height of the sound pressure wave or the `loudness' of a sound and is 
typically measured using the dB scale. A dB is the ratio between a 
measured pressure (with sound) and a reference pressure (sound at a 
constant pressure, established by scientific standards). It is a 
logarithmic unit that accounts for large variations in amplitude; 
therefore, relatively small changes in dB ratings correspond to large 
changes in sound pressure. When referring to sound pressure levels 
(SPLs; the sound force per unit area), sound is referenced in the 
context of underwater sound pressure to one microPascal ([mu]Pa). One 
pascal is the pressure resulting from a force of one

[[Page 12160]]

newton exerted over an area of one square meter. The source level (SL) 
represents the sound level at a distance of 1 m from the source 
(referenced to 1 [mu]Pa). The received level is the sound level at the 
listener's position. Note that all underwater sound levels in this 
document are referenced to a pressure of 1 [micro]Pa and all airborne 
sound levels in this document are referenced to a pressure of 20 
[micro]Pa.
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. Rms is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick 1983). Rms accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    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 all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. 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. Ambient 
sound is defined as environmental background sound levels lacking a 
single source or point (Richardson et al., 1995), and 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., 
waves, earthquakes, ice, atmospheric sound), biological (e.g., sounds 
produced by marine mammals, fish, and invertebrates), and anthropogenic 
sound (e.g., vessels, dredging, aircraft, construction). A number of 
sources contribute to ambient sound, including the following 
(Richardson et al., 1995):
     Wind and waves: The complex interactions between wind and 
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of 
naturally occurring ambient noise 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. Surf noise becomes 
important near shore, with measurements collected at a distance of 8.5 
km from shore showing an increase of 10 dB in the 100 to 700 Hz band 
during heavy surf conditions.
     Precipitation: Sound from rain and hail impacting the 
water surface can become an important component of total noise at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times.
     Biological: Marine mammals can contribute significantly to 
ambient noise levels, as can some fish and shrimp. The frequency band 
for biological contributions is from approximately 12 Hz to over 100 
kHz.
     Anthropogenic: Sources of ambient noise related to human 
activity include transportation (surface vessels and aircraft), 
dredging and construction, oil and gas drilling and production, seismic 
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise 
typically dominates the total ambient noise 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 (Richardson et al., 1995). Sound from identifiable 
anthropogenic sources other than the activity of interest (e.g., a 
passing vessel) is sometimes termed background sound, as opposed to 
ambient sound.
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving and removal, and 
drilling. The sounds produced by these activities fall into one of two 
general sound 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.
    Pulsed sound sources (e.g., 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; Harris 1998; NIOSH 1998; ISO 2003; ANSI 2005) 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 non-continuous (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.
    Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper 2005). Vibratory 
hammers install piles by vibrating them and allowing the weight of the 
hammer to push them into the sediment. Vibratory hammers produce 
significantly less sound than impact hammers. Peak SPLs may be 180 dB 
or greater, but are generally 10 to 20 dB lower than SPLs generated 
during impact pile driving of the same-sized pile (Oestman et al., 
2009). Rise time is slower, reducing the probability and

[[Page 12161]]

severity of injury, and sound energy is distributed over a greater 
amount of time (Nedwell and Edwards 2002; Carlson et al., 2005). 
Drilling to insert the steel piles (not for tension anchors) will be 
operated by a down-hole hammer. A down-hole hammer is a drill bit that 
drills through the bedrock using a pulse mechanism that functions at 
the bottom of the hole. This pulsing bit breaks up rock to allow 
removal of debris and insertion of the pile. The head extends so that 
the drilling takes place below the pile. The pulsing sounds produced by 
the hammer method are continuous and reduces sound attenuation because 
the noise is primarily contained within the steel pile and below ground 
rather than impact hammer driving methods which occur at the top of the 
pile (R&M 2016).

Acoustic Impacts

    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; Gotz 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 ADOT&PF's construction 
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 be 
audible (potentially perceived) to the animal, but not strong enough to 
elicit any overt behavioral or physiological response. The next zone 
corresponds with the area where the signal is audible to the animal and 
of sufficient intensity to elicit behavioral or physiological 
responsiveness. Third is a zone within which, for signals of high 
intensity, the received level is sufficient to potentially cause 
discomfort or tissue damage to auditory or other systems. Overlaying 
these zones to a certain extent is the area within which masking (i.e., 
when a sound interferes with or masks the ability of an animal to 
detect a signal of interest that is above the absolute hearing 
threshold) may occur; the masking zone may be highly variable in size.
    We describe the more severe effects (i.e., permanent hearing 
impairment, certain non-auditory physical or physiological effects) 
only briefly as we do not expect that there is a reasonable likelihood 
that ADOT&PF's activities may result in such effects (see below for 
further discussion). 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 (Kastak et al., 1999; Schlundt et al., 2000; 
Finneran et al., 2002, 2005b). TS can be permanent (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--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several dB above a 40-dB threshold shift approximates PTS 
onset; e.g., Kryter et al., 1966; Miller, 1974 found 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 a 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 (e.g., Finneran et al., 2002; Nachtigall et al., 
2004; Kastak et al., 2005; Lucke et al., 2009; Popov et al., 2011). In 
general, harbor seals (Kastak et al., 2005; Kastelein et al., 2012a) 
and harbor porpoises (Lucke et al., 2009; Kastelein et al., 2012b) have 
a lower TTS onset than other measured pinniped or cetacean species. 
Additionally, the

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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) and Finneran and Jenkins (2012).
    In addition to PTS and TTS, there is a potential for 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. These 
impacts can 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). The AKOT & PF's 
activities do not involve the use of devices such as explosives or mid-
frequency active sonar that are associated with these types of effects.
    When a live or dead marine mammal swims or floats onto shore and is 
incapable of returning to sea, the event is termed a ``stranding'' (16 
U.S.C. 1421h(3)). Marine mammals are known to strand for a variety of 
reasons, such as infectious agents, biotoxicosis, starvation, fishery 
interaction, ship strike, unusual oceanographic or weather events, 
sound exposure, or combinations of these stressors sustained 
concurrently or in series (e.g., Geraci et al., 1999). However, the 
cause or causes of most strandings are unknown (e.g., Best 1982). 
Combinations of dissimilar stressors may combine to kill an animal or 
dramatically reduce its fitness, even though one exposure without the 
other would not be expected to produce the same outcome (e.g., Sih et 
al., 2004). For further description of stranding events see, e.g., 
Southall et al., 2006; Jepson et al., 2013; Wright et al., 2013.
    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 (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 seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and Bejder 2007; Weilgart 2007; NRC 2005). 
However, there are broad categories of potential response, which we 
describe in greater detail here, that include alteration of dive 
behavior, alteration of foraging behavior, effects to breathing, 
interference with or alteration of vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely, and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark 2000; Costa et al., 2003; Ng and Leung 2003; Nowacek et al., 
2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be

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unaffected or could increase, depending on the species and signal 
characteristics, again highlighting the importance in understanding 
species differences in the tolerance of underwater noise when 
determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
(Eubalaena glacialis) have been observed to shift the frequency content 
of their calls upward while reducing the rate of calling in areas of 
increased anthropogenic noise (Parks et al., 2007b). 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 because of the presence of a sound or other stressors, 
and is one of the most obvious manifestations of disturbance in marine 
mammals (Richardson et al., 1995). For example, gray whales 
(Eschrictius robustus) are known to change direction--deflecting from 
customary migratory paths--in order to avoid noise from seismic surveys 
(Malme et al., 1984). Avoidance may be short-term, with animals 
returning to the area once the noise has ceased (e.g., Bowles et al., 
1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey 
et al., 2007). Longer-term displacement is possible, however, which may 
lead to changes in abundance or distribution patterns of the affected 
species in the affected region if habituation to the presence of the 
sound does not occur (e.g., Blackwell et al., 2004; Bejder et al., 
2006; Teilmann et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus 1996). The result of a flight response could range from brief, 
temporary exertion and displacement from the area where the signal 
provokes flight to, in extreme cases, marine mammal strandings (Evans 
and England 2001). However, it should be noted that response to a 
perceived predator does not necessarily invoke flight (Ford and Reeves 
2008), and whether individuals are solitary or in groups may influence 
the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil 1997; Fritz et al., 2002; Purser and Radford 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle 1950; Moberg 
2000). In many cases, an animal's first and sometimes most economical 
(in terms of energetic costs) response is behavioral avoidance of the 
potential stressor. Autonomic nervous system responses to stress 
typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg 1987; Blecha 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker 2000; Romano 
et al., 2002b) and, more rarely, studied in wild populations (e.g., 
Romano et al., 2002a). For

[[Page 12164]]

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). 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 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., 2007b; 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.

Acoustic Effects, Underwater

    Potential Effects of DTH drilling and Pile Driving--The effects of 
sounds from DTH drilling and pile driving might include one or more of 
the following: temporary or permanent hearing impairment, non-auditory 
physical or physiological effects, behavioral disturbance, and masking 
(Richardson et al., 1995; Gordon et al., 2003; Nowacek et al., 2007; 
Southall et al., 2007). The effects of pile driving or drilling on 
marine mammals are dependent on several factors, including the type and 
depth of the animal; the pile size and type, and the intensity and 
duration of the pile driving or drilling sound; the substrate; the 
standoff distance between the pile and the animal; and the sound 
propagation properties of the environment. Impacts to marine mammals 
from pile driving and DTH drilling activities are expected to result 
primarily from acoustic pathways. As such, the degree of effect is 
intrinsically related to the frequency, received level, and duration of 
the sound exposure, which are in turn influenced by the distance 
between the animal and the source. The further away from the source, 
the less intense the exposure should be. The substrate and depth of the 
habitat affect the sound propagation properties of the environment. In 
addition, substrates that are soft (e.g., sand) would absorb or 
attenuate the sound more readily than hard substrates (e.g., rock), 
which may reflect the acoustic wave. Soft porous substrates would also 
likely require less time to drive the pile, and possibly less forceful 
equipment, which would ultimately decrease the intensity of the 
acoustic source.
    In the absence of mitigation, impacts to marine species could be 
expected to include physiological and behavioral responses to the 
acoustic signature (Viada et al., 2008). Potential effects from 
impulsive sound sources like pile driving can range in severity from 
effects such as behavioral disturbance to temporary or permanent 
hearing impairment (Yelverton et al., 1973). Due to the nature of the 
pile driving sounds in the project, behavioral disturbance is the most 
likely effect from the proposed activity. Marine mammals exposed to 
high intensity sound repeatedly or for prolonged periods can experience 
hearing threshold shifts. PTS constitutes injury, but TTS does not 
(Southall et al., 2007). Based on the best scientific information 
available, the SPLs for the construction activities in this project are 
below the thresholds that could cause TTS or the onset of PTS (Table 5 
in Estimated Take Section).
    Non-Auditory Physiological Effects--Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, resonance effects, and other types of organ 
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies 
examining such effects are limited. In general, little is known about 
the potential for pile driving or removal to cause auditory impairment 
or other physical effects in marine mammals. Available data suggest 
that such effects, if they occur at all, would presumably be limited to 
short distances from the sound source and to activities that extend 
over a prolonged period. The available data do not allow identification 
of a specific exposure level above which non-auditory effects can be 
expected

[[Page 12165]]

(Southall et al., 2007) or any meaningful quantitative predictions of 
the numbers (if any) of marine mammals that might be affected in those 
ways. Marine mammals that show behavioral avoidance of pile driving, 
including some odontocetes and some pinnipeds, are especially unlikely 
to incur auditory impairment or non-auditory physical effects.

Disturbance Reactions

    Responses to continuous sound, such as vibratory pile installation, 
have not been documented as well as responses to pulsed sounds. With 
both types of pile driving, it is likely that the onset of pile driving 
could result in temporary, short-term changes in an animal's typical 
behavior 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 (e.g., pinnipeds flushing into water from haulouts 
or rookeries). Pinnipeds may increase their haul-out time, possibly to 
avoid in-water disturbance (Thorson and Reyff 2006). If a marine mammal 
responds to a stimulus by changing its behavior (e.g., through 
relatively minor changes in locomotion direction/speed or vocalization 
behavior), the response may or may not constitute taking at the 
individual level, and is unlikely to affect the stock or the species as 
a whole. However, if a sound source displaces marine mammals from an 
important feeding or breeding area for a prolonged period, impacts on 
animals, and if so potentially on the stock or species, could 
potentially be significant (e.g., Lusseau and Bejder 2007; Weilgart 
2007).
    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 biologically significant if the change affects 
growth, survival, or reproduction. Significant behavioral modifications 
that could potentially lead to effects on growth, survival, or 
reproduction include:
     Drastic changes in diving/surfacing patterns (such as 
those thought to cause beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Longer-term habitat abandonment due to loss of desirable 
acoustic environment; and
     Longer-term cessation of feeding or social interaction.
    The onset of behavioral disturbance from anthropogenic sound 
depends on both external factors (characteristics of sound sources and 
their paths) and the specific characteristics of the receiving animals 
(hearing, motivation, experience, demography) and is difficult to 
predict (Southall et al., 2007).

Auditory Masking

    Natural and artificial sounds can disrupt behavior by masking. The 
frequency range of the potentially masking sound is important in 
determining any potential behavioral impacts. Because sound generated 
from in-water pile driving and removal and DTH drilling is mostly 
concentrated at low-frequency ranges, it may have less effect on high 
frequency echolocation sounds made by porpoises. The most intense 
underwater sounds in the proposed action are those produced by impact 
pile driving. Given that the energy distribution of pile driving covers 
a broad frequency spectrum, sound from these sources would likely be 
within the audible range of marine mammals present in the project area. 
Impact pile driving activity is relatively short-term, with rapid 
pulses occurring for approximately fifteen minutes per pile. The 
probability for impact pile driving resulting from this proposed action 
masking acoustic signals important to the behavior and survival of 
marine mammal species is low. Vibratory pile driving is also relatively 
short-term, with rapid oscillations occurring for approximately one and 
a half hours per pile. It is possible that vibratory pile driving 
resulting from this proposed action may mask acoustic signals important 
to the behavior and survival of marine mammal species, but the short-
term duration and limited affected area would result in insignificant 
impacts from masking. 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 DTH drilling and 
vibratory and impact pile driving, and which have already been taken 
into account in the exposure analysis.
    Acoustic Effects, Airborne--Pinnipeds that occur near the project 
site could be exposed to airborne sounds associated with pile driving 
and removal and DTH drilling that have the potential to cause 
behavioral harassment, depending on their distance from pile driving 
activities. Cetaceans are not expected to be exposed to airborne sounds 
that would result in harassment as defined under the MMPA.
    Airborne noise will primarily be an issue for pinnipeds that are 
swimming or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. We recognize that 
pinnipeds in the water could be exposed to airborne sound that may 
result in behavioral harassment when looking with their heads above 
water. Most likely, airborne sound would cause behavioral responses 
similar to those discussed above in relation to underwater sound. For 
instance, anthropogenic sound could cause hauled-out pinnipeds to 
exhibit changes in their normal behavior, such as reduction in 
vocalizations, or cause them to temporarily abandon the area and move 
further from the source. However, these animals would previously have 
been `taken' because of exposure to underwater sound above the 
behavioral harassment thresholds, which are in all cases larger than 
those associated with airborne sound. Thus, the behavioral harassment 
of these animals is already accounted for in these estimates of 
potential take. Multiple instances of exposure to sound above NMFS' 
thresholds for behavioral harassment are not believed to result in 
increased behavioral disturbance, in either nature or intensity of 
disturbance reaction. Therefore, we do not believe that authorization 
of incidental take resulting from airborne sound for pinnipeds is 
warranted, and airborne sound is not discussed further here.

Anticipated Effects on Habitat

    The proposed activities at the project area would not result in 
permanent negative impacts to habitats used directly by marine mammals, 
but may have potential short-term impacts to food sources such as 
forage fish and may affect acoustic habitat (see masking discussion 
above). There are no known foraging hotspots or other ocean bottom 
structure of significant biological importance to marine mammals 
present in the marine waters of the project area during the 
construction window. 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 in this document. The primary potential acoustic impacts to 
marine mammal habitat are associated with elevated sound levels 
produced by vibratory and impact pile driving and removal and DTH 
drilling in the area. However, other potential impacts to the

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surrounding habitat from physical disturbance are also possible.

In-Water Construction Effects on Potential Prey (Fish)

    Construction activities would produce continuous (i.e., vibratory 
pile driving and DTH drilling) and pulsed (i.e. impact driving) sounds. 
Fish react to sounds that are especially strong and/or intermittent 
low-frequency sounds. Short duration, sharp sounds can cause overt or 
subtle changes in fish behavior and local distribution. Hastings and 
Popper (2005) identified several studies that suggest fish may relocate 
to avoid certain areas of sound energy. Additional studies have 
documented effects of pile driving on fish, although several are based 
on studies in support of large, multiyear bridge construction projects 
(e.g., Scholik and Yan 2001, 2002; Popper and Hastings 2009). Sound 
pulses at received levels of 160 dB may cause subtle changes in fish 
behavior. SPLs of 180 dB may cause noticeable changes in behavior 
(Pearson et al., 1992; Skalski et al., 1992). SPLs of sufficient 
strength have been known to cause injury to fish and fish mortality.
    The most likely impact to fish from pile driving and drilling 
activities at the project area would be temporary behavioral avoidance 
of the area. The duration of fish avoidance of this area after pile 
driving stops is unknown, but a rapid return to normal recruitment, 
distribution and behavior is anticipated. In general, impacts to marine 
mammal prey species are expected to be minor and temporary due to the 
short timeframe for the project.

Pile Driving Effects on Potential Foraging Habitat

    The area likely impacted by the project is relatively small 
compared to the available habitat in Tenakee Inlet (e.g., most of the 
impacted area is limited near the mouth of the inlet. Avoidance by 
potential prey (i.e., fish) of the immediate area due to the temporary 
loss of this foraging habitat is also possible. The duration of fish 
avoidance of this area after pile driving stops is unknown, but a rapid 
return to normal recruitment, distribution and behavior is anticipated. 
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 in Tenakee Inlet.
    The duration of the construction activities is relatively short. 
The construction window is for a maximum of 93 days and each day, 
construction activities would only occur for a few hours during the 
day. Impacts to habitat and prey are expected to be minimal based on 
the short duration of activities.
    In summary, given the short daily duration of sound associated with 
individual pile driving and drilling events and the relatively small 
areas being affected, pile driving and drilling activities associated 
with the proposed action are not likely to have a permanent, adverse 
effect on any fish habitat, or populations of fish species. Thus, any 
impacts to marine mammal habitat are not expected to cause significant 
or long-term consequences for individual marine mammals or their 
populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of whether the number of takes is ``small'' and the 
negligible impact determination.
    Harassment is the only type of take expected to result from these 
activities. Except with respect to certain activities not pertinent 
here, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would be by Level B harassment only, in the form 
of disruption of behavioral patterns for individual marine mammals 
resulting from exposure to pile driving and drilling. Based on the 
nature of the activity and the anticipated effectiveness of the 
mitigation measures (i.e., shutdowns--discussed in detail below in 
Proposed Mitigation section), Level A harassment is neither anticipated 
nor proposed to be authorized. As described previously, no mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the take is estimated.
    Described in the most basic way, 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. Below, we describe these 
components 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 for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2011). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g. 
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms) 
for non-explosive impulsive (e.g., seismic airguns and impact pile 
driving) or intermittent (e.g., scientific sonar) sources.
    ADOT&PF's proposed activity includes the use of continuous 
(vibratory pile driving and drilling) and impulsive (impact pile 
driving) sources, and therefore the 120 and 160 dB re 1 [mu]Pa (rms) 
thresholds are applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Technical Guidance, 2016) identifies dual criteria to 
assess auditory injury (Level A harassment) to five different marine 
mammal groups (based on hearing sensitivity) because of exposure to 
noise from two different types of sources (impulsive or non-impulsive).
    These thresholds were developed by compiling and synthesizing the 
best available science and soliciting input multiple times from both 
the public and

[[Page 12167]]

peer reviewers to inform the final product, and are provided in Table 5 
below. The references, analysis, and methodology used in the 
development of the thresholds are described in NMFS' 2016 Technical 
Guidance, which may be accessed at: https://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

                     Table 5--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                    PTS onset acoustic thresholds \1\ (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-frequency cetaceans................  Lpk,flat: 219 dB;           LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-frequency cetaceans................  Lpk,flat: 230 dB;           LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-frequency cetaceans...............  Lpk,flat: 202 dB;           LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (underwater)..........  Lpk,flat: 218 dB;           LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (underwater).........  Lpk,flat: 232 dB;           LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
\1\ NMFS 2016.

    Although ADOT&PF's construction activity includes the use of 
impulsive (impact pile driving) and non-impulsive (vibratory pile 
driving and drilling) sources, the shutdown zones set by the applicant 
are large enough to ensure Level A harassment will be prevented. The 
level A zones for the proposed project are illustrated in Table 7. The 
highest level A zone shown (176 meters for high- and low-frequency 
cetaceans) is roughly 24 meters less than the total distance of the 
largest shutdown zone (200 meters for high- and low-frequency 
cetaceans). To assure the largest shutdown zone can be fully monitored, 
protected species observers (PSOs) will be positioned in the possible 
best vantage points during all piling/drilling activities to guarantee 
a shutdown if a high- and/or low-frequency cetacean approaches or 
enters the 200-meter shutdown zone. These measures are described in 
full detail below in the Proposed Mitigation and Monitoring Sections.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds.
    The sound field in the project area is the existing background 
noise plus additional construction noise from the proposed project. 
Marine mammals are expected to be affected via sound generated by the 
primary components of the project, i.e., impact pile driving, vibratory 
pile driving, and vibratory pile removal. Vibratory hammers produce 
constant sound when operating, and produce vibrations that liquefy the 
sediment surrounding the pile, allowing it to penetrate to the required 
seating depth. An impact hammer would then generally be used to place 
the pile at its intended depth. The actual durations of each 
installation method vary depending on the type and size of the pile. An 
impact hammer is a steel device that works like a piston, producing a 
series of independent strikes to drive the pile. Impact hammering 
typically generates the loudest noise associated with pile 
installation. Factors that could potentially minimize the potential 
impacts of pile installation associated with the project include:
     The relatively shallow waters in the project area (Taylor 
et al., 2008);
     Land forms around Tenakee Springs that would block the 
noise from spreading; and
     Vessel traffic and other commercial and industrial 
activities in the project area that contribute to elevated background 
noise levels.
    In order to calculate distances to the Level A and Level B sound 
thresholds for piles of various sizes being used in this project, NMFS 
used acoustic monitoring data from other locations (see Table 6). Note 
that piles of differing sizes have different sound source levels.
    Empirical data from recent ADOT&PF sound source verification (SSV) 
studies at Ketchikan, Kodiak, and Auke Bay, Alaska were used to 
estimate sound source levels (SSLs) for vibratory, impact, and drilling 
installations of 30-inch steel pipe piles (MacGillivray et al., 2016, 
Warner and Austin 2016b, Denes et al., 2016a, respectively). These 
Alaskan construction sites were generally assumed to best represent the 
environmental conditions found in Tenakee and represent the nearest 
available source level data for 30-inch steel piles. Similarities among 
the sites include thin layers of soft sediments overlying a bedrock 
layer and comparable bedrock depths. However, the use of data from 
Alaska sites was not appropriate in all instances. Details are 
described below.
    For vibratory driving of 24-inch steel piles, data from two Navy 
project locations in the state of Washington were reviewed. These 
include data from proxy sound source values at Navy installations in 
Puget Sound (Navy, 2015) and along the waterfront at Naval Base Kitsap 
(NBK), Bangor (Navy 2012). After assessing these two sources, ADOT&PF 
selected an average source level of 161 dB rms, which NMFS concurs with 
as an appropriate sound source. In addition, for a fourth project at 
NBK, Bangor, construction crews drove 16-inch hollow steel piles with 
measured levels similar to those for the 24-inch piles. Therefore, NMFS 
elects to use 161 dB rms as a source level for vibratory driving of 18-
inch and 16-inch steel piles.
    For vibratory driving of 14-inch steel and timber piles and 12.75-
inch steel piles, ADOT&PF suggested a source level of 155 dB rms, which 
NMFS also concurs with. This source level was derived from summary data 
pertaining to vibratory driving of 18-inch steel piles in Kake, Alaska 
(MacGillivray 2015).
    In their application, ADOT&PF derived source levels for impact 
driving of 30-inch steel piles by averaging the individual mean values 
associated with impact driving of the same size and type from Ketchikan 
(Warner and Austin 2016a). Mean values from Ketchikan were the most 
conservative dataset for 30-inch impact pile driving in Southeast 
Alaska. The average mean value from this dataset was 194.7 dB rms and 
180.8 dB SEL.
    For 24-inch impact pile driving, NMFS used data from a Navy (2015) 
study of proxy sound source values for use at Puget Sound military 
installations. The Navy study recommended a value of 193 dB rms and 181 
dB SEL, which was derived from data generated by impact driving of 24-
inch steel piles at the Bainbridge Island Ferry Terminal Preservation 
project and the Friday Harbor Restoration Ferry Terminal project. NMFS 
found this estimated source level to be appropriate.

[[Page 12168]]

    For impact driving of 20, 18, and 14-inch steel piles, ADOT&PF used 
source levels of 186.6 dB, 158 dB, and 158 dB respectively. These 
source levels were derived from Caltrans SSV studies at the Stockton 
Wastewater Treatment Plant (20-inch) and Caltrans SSV studies at 
Prichard Lake Pumping Plant in Sacramento, CA (18 and 14-inch) 
(Caltrans 2015). In regards to the proposed drilling activities, a 
source level of 165 dB for all pile types originated from ADOT&PF SSV 
studies for piling operations in Kodiak, Alaska (Warner and Austin 
2016b).

   Table 6--Estimates of Mean Underwater Sound Levels Generated During Vibratory and Impact Pile Installation,
                                      Drilling, and Vibratory Pile Removal
----------------------------------------------------------------------------------------------------------------
                                                                  Sound level at 10 meters
      Method and pile type        Installation, removal, or  --------------------------------- Literature source
                                           proofing             dB rms     dB SEL    dB peak
----------------------------------------------------------------------------------------------------------------
Vibratory Hammer:
    30-inch steel piles........  Install....................      165.0  .........  .........  Derived from
                                                                                                Warner and
                                                                                                Austin 2016a &
                                                                                                Denes et al.
                                                                                                2016.
    24-inch steel piles........  Install....................      161.0  .........  .........  Navy 2012, 2015.
    20-inch steel piles........  Install....................      161.0  .........  .........  Navy 2012, 2015.
    18-inch steel piles........  Remove, Install............      161.0  .........  .........  Navy 2012, 2015.
    16-inch steel piles........  Remove.....................      161.0  .........  .........  Navy 2012, 2015.
    14-inch steel piles........  Remove.....................      155.0  .........  .........  MacGillivray et
                                                                                                al. 2015.
    14-inch timber piles.......  Remove, Install............      155.0  .........  .........  MacGillivray et
                                                                                                al. 2015.
    12.75-inch steel piles.....  Remove.....................      155.0  .........  .........  MacGillivray et
                                                                                                al. 2015.
Drilling:
    30-inch steel piles........  Install....................      165.0  .........  .........  Derived from
                                                                                                Warner and
                                                                                                Austin 2016b.
    24-inch steel piles........  Install....................      165.0  .........  .........  Derived from
                                                                                                Warner and
                                                                                                Austin 2016b.
    20-inch steel piles........  Install....................      165.0  .........  .........  Derived from
                                                                                                Warner and
                                                                                                Austin 2016b.
    18-inch steel piles........  Install....................      165.0  .........  .........  Derived from
                                                                                                Warner and
                                                                                                Austin 2016b.
Impact Hammer:
    30-inch steel piles........  Proofing...................      194.7      180.8      208.6  Warner and Austin
                                                                                                2016a.
    24-inch steel piles........  Proofing...................      193.0      181.0      210.0  Navy 2015 (from
                                                                                                82 FR 31400).
    20-inch steel piles........  Proofing...................      186.5      175.5      207.0  Caltrans 2015.
    18-inch steel piles........  Proofing...................      158.0  .........      174.0  Caltrans 2015.
    14-inch timber piles.......  Install....................      158.0  .........      174.0  Caltrans 2015.
----------------------------------------------------------------------------------------------------------------

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

TL = B * log 10 (R\1\/R\2\)

    \1\ The distance of the modeled SPL from the driven pile.
    \2\ The distance from the driven pile of the initial 
measurement.

---------------------------------------------------------------------------
Where:

TL = transmission loss in dB
B = transmission loss coefficient; for practical spreading equals 15

    NMFS typically recommends a default practical spreading loss of 15 
dB tenfold increase in distance. ADOT&PF analyzed the available 
underwater acoustic data utilizing this metric.
    When 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 will result in some degree of 
overestimate of Level A take. However, these tools offer the best way 
to predict appropriate isopleths when more sophisticated 3D modeling 
methods are not available, and NMFS continues to develop ways to 
quantitatively refine these tools, and will qualitatively address the 
output where appropriate. For stationary sources such as pile driving 
and drilling, NMFS' User Spreadsheet 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 and the resulting isopleths are reported in Tables 6 and 7.

                     Table 7--Calculated Distances to Level A and Level B Harassment Isopleths During Pile Installation and Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Level A harassment zone (meters) \1\         Level B
                                                                                   Piles    ---------------------------------------------   harassment
                 Type of pile                              Activity              installed           Cetaceans              Pinnipeds     zone (meters),
                                                                                 or removed ---------------------------------------------  cetaceans and
                                                                                  per day       LF       MF       HF       PW       OW     pinnipeds \2\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Vibratory (120 dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
30-inch steel................................  Install \4\....................            3       11        1       16        7        1          10,000

[[Page 12169]]

 
24-inch steel, 20-inch steel, 18-inch steel..  Install \4\....................            3        6        1        9        4        1           5,412
18-inch steel, 16-inch steel.................  Remove \4\.....................           10       13        2       19        8        1           5,412
14-inch steel, 14-inch timber, 12.75-inch      Remove \5\.....................           10        5        1        8        3        1           2,154
 steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Drilling (120 dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
30-inch steel, 20-inch steel.................  Install \6\....................            3       55        5       81       34        3          10,000
24-inch steel, 18-inch steel.................  Install \7\....................            3       42        4       62       26        2          10,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Impact (160 dB) \3\
--------------------------------------------------------------------------------------------------------------------------------------------------------
30-inch steel................................  Proofing.......................            1       70        3       82       37        3           2,057
                                               ...............................            2      110        4      131       59        5
                                               ...............................            3      144        6      171       77        6
24-inch steel................................  Proofing.......................            1       71        3       85       38        3           1,585
                                               ...............................            2      113        4      135       61        5
                                               ...............................            3      148        6      176       79        6
20-inch steel................................  Proofing.......................            3       64        3       76       34        3             584
18-inch steel................................  Proofing.......................            3       <1       <1       <1       <1       <1               7
14-inch timber...............................  Install........................           10       <1       <1       <1       <1       <1               7
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Level A Isopleths Calculated Using NMFS' 2016 Acoustic User Spreadsheet. Source level set at a distance of 10 Meters, a weighting factor adjustment
  of 2kHz for impulse sources and 2.5kHz for continuous sources, and a propagation loss value of 15 LogR.
\2\ Level B Isopleths Calculated using Practical Spreading Loss Model. Source level set at a distance of 10 meters and and a propagation loss value of
  15 LogR.
\3\ 30 Strikes per pile.
\4\ 45 minute activity duration.
\5\ 2.5 hour activity duration.
\6\ 9 hour activity duration.
\7\ 6 hour activity duration.

    Pulse duration from the SSV studies described above are unknown. 
However, all necessary parameters were available for the SELcum 
(cumulative Single Strike Equivalent) method for calculating isopleths 
for 30-inch, 24-inch, and 20-inch impact piles. Therefore, this method 
was selected for those piles. To account for potential variations in 
daily productivity during impact installation, isopleths were 
calculated for different numbers of piles that could be installed each 
day (see Table 7). Should the contractor expect to install fewer piles 
in a day than the maximum anticipated, a smaller Level A shutdown zone 
would be employed to monitor take.
    To derive Level A harassment isopleths associated with impact 
driving 30-inch steel piles, ADOT&PF utilized a single strike SEL of 
180.8 dB and assumed 30 strikes per pile for 1 to 3 piles per day. For 
24-inch and 20-inch steel piles, ADOT&PF used a single strike SEL of 
181 dB SEL and 175.5 SEL respectively, also assuming 30 strikes at a 
rate of 1 to 3 piles per day. To calculate Level A harassment isopleths 
associated with impact piling 18-inch and 14-inch steel/timber piles, a 
source level (rms SPL) of 158dB was used with a pulse duration of .05 
seconds.
    To calculate Level A harassment for vibratory driving of 30-inch 
piles, ADOT&PF utilized a source level (rms SPL) of 165 dB and assumed 
45 minutes of driving per day. For installing 24, 20, and 18-inch 
piles, ADOT&PF used a source level of 161 dB and assumed up to 45 
minutes of driving per day. For removal of 18 and 16-inch piles, 
ADOT&PF assumed use of 18-inch piles and used the same source level of 
161 dB for up to 45 minutes. Level A harassment for the installation/
removal of piles 14-inches and under in diameter used a source level of 
155 dB rms and assumed 2.5 hours of driving/removal a day. In regards 
to Level A for drilling, a source level of 165 dB rms was used for all 
pile types with varying levels of activity for each pile type (see 
Tables 1 & 2 for information on drilling duration and max number of 
piles drilled each day). Results for all Level A isopleths are shown in 
Table 7. Isopleths for Level B harassment associated with impact (160 
dB) and vibratory harassment (120 dB) were also calculated and are 
included in Table 7.
    It is important to note that the actual area ensonified by pile 
driving activities is constrained by local topography relative to the 
total threshold radius (particularly for the Level B ensonified zones). 
The actual ensonified area was determined using a straight line-of-
sight projection from the anticipated pile driving locations. Overall, 
Level A harassment zones for impact installation are relatively small 
because of the few strikes required to proof the piles. The maximum 
aquatic areas ensonified within the Level A harassment isopleths do not 
exceed 0.1 square km (see Figures 6-1 and Figure 6-2 in application). 
The corresponding areas of the Level B ensonified zones for impact 
driving and vibratory installation/removal are shown in Table 8 below.

[[Page 12170]]



Table 8--Calculated Areas Ensonified Within Level B Harassment Isopleths
                  During Pile Installation and Removal
------------------------------------------------------------------------
                                                              Level B
                                                            harassment
           Type of pile                   Activity         zone (km\2\),
                                                           cetaceans and
                                                             pinnipeds
------------------------------------------------------------------------
                           Vibratory (120 dB)
------------------------------------------------------------------------
30-inch steel.....................  Install.............            78.9
24-, 20-, 18-, and 16-inch steel..  Install.............            45.3
14-, 12.75-inch steel, and 14-inch  Remove..............             7.3
 timber.
------------------------------------------------------------------------
                            Drilling (120 dB)
------------------------------------------------------------------------
30-, 24-, 20-, and 18-inch steel..  Install.............            78.9
------------------------------------------------------------------------
                             Impact (160 dB)
------------------------------------------------------------------------
30-inch steel.....................  Proofing............             6.7
24-inch steel.....................  Proofing............             4.0
20-inch steel.....................  Proofing............             0.6
18-inch steel.....................  Proofing............            <0.1
14-inch timber....................  Install.............            <0.1
------------------------------------------------------------------------

Marine Mammal Occurrence and Final Take Estimates

    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 and vibratory pile driving 
noise for each threshold were estimated using local marine mammal 
density datasets where available and local observational data. As 
previously stated, only Level B take will be considered for this action 
as Level A take will be avoided via mitigation (see Mitigation and 
Monitoring Sections). As presented in Table 7, the largest Level A zone 
for the project is 176 meters for high- and low-frequency cetaceans. As 
a result, the shutdown zone (which is described in detail in the 
Proposed Mitigation Section) for these activities will be 200 meters 
for high- and low-frequency cetaceans. Level B take is calculated 
differently for some species based on differences in density, year-
round habitat use, and other contextual factors. See below for specific 
methodologies by species.
Steller Sea Lions
    Steller sea lion abundance in the project area is highly seasonal 
in nature with sea lions being most active between October and March 
(Figure 4-2). Level B exposure estimates are conservatively based on 
the average winter (October to March) abundance of 140 sea lions at the 
Tenakee Cannery haulout, which is 8.9 km away from the project site 
(Jemison, 2017, unpublished data). However, it is unlikely that the 
entire Steller sea lion population from the Tenakee Cannery haulout 
would forage to the west near the Tenakee Springs ferry terminal. 
Additionally, Steller sea lions do not generally forage every day, but 
tend to forage every 1-2 days and return to haulouts to rest between 
foraging trips (Merrick and Loughlin 1997; Rehburg et al., 2009). 
Overall, this information indicates that only half of the Steller sea 
lions at the Tenakee Cannery haulout (i.e., average of 140 during 
winter) is likely to approach the project site on any given day and be 
exposed to sound levels that constitute behavioral harassment. As a 
result, an estimated 70 individuals is a conservative estimate of the 
number of Steller sea lions likely to forage in the underwater 
behavioral harassment zone on a given day. Therefore: 70 Steller sea 
lions per day * 93 days of potential exposure = 6,510 potential 
exposures.
    To assign take to the eDPS and wDPS stocks of Steller sea lions, 
data from researchers at NMFS' Alaska Fisheries Science Center were 
used. Researchers at NMFS' Alaska Fisheries Science Center state that 
roughly 17.8 percent of Steller sea lions at the Tenakee Cannery Point 
haulout are members of the wDPS whereas 82.2 percent are from the eDPS 
(L. Fritz, pers. comm; L. Fritz, unpublished data). Therefore, it is 
estimated that only 1,159 takes (17.8 percent of 6,510) have the 
potential to occur for wDPS Steller sea lions and 5,351 (82.2 percent 
of 6,510) takes have the potential to occur for eDPS Steller sea lions. 
In addition, since there is only an average of 140 Steller sea lions 
located at the Tenakee Cannery haulout, it is predicted that only 115 
(82.2 percent of 140) individuals from the eDPS and 25 (17.8 percent of 
140) individuals from the wDPS have the potential to be harassed.
Harbor Seals
    Harbor seals are non-migratory; therefore, the exposure estimates 
are not dependent on season. We anticipate Level B harbor seal take to 
be relatively high, given the presence of three established haulouts 
within the largest (ten km) Level B harassment zone of the project 
site. The best available abundance estimate for Tenakee Inlet is 259 
individual harbor seals (London, J., pers. comm.).
    The number of harbor seals that could potentially be exposed to 
elevated sound levels for the project was estimated by calculating the 
percentage of available harbor seal habitat within the largest Level B 
harassment zone. Of the 233.35 square km of available habitat in 
Tenakee Inlet, 78.9 square km or 33.82 percent will be within the 
largest Level B harassment zone. Of the 259 harbor seals that haul out 
in the Inlet, approximately 87.57 harbor seals (33.82 percent of 259 
individuals) could be within the Level B harassment zone and exposed to 
sound levels that reach the Level B threshold each day. Therefore: 
87.57 harbor seals per day * 93 days of potential exposure = 8,144 
potential exposures.
Harbor Porpoises
    Harbor porpoises are non-migratory; therefore, our exposure 
estimates are not dependent on season. Harbor porpoise surveys 
conducted in southeast Alaska during the summers of 1991-1993, 2006, 
2007, and 2010-2012 included

[[Page 12171]]

Chatham Strait (near the action area). The average density estimate for 
all survey years in Chatham Strait was 0.013 harbor porpoise per square 
km (Dahlheim et al., 2015). Surveys in 1997, 1998, and 1999 reported an 
average harbor porpoise density of .033 per square km in Southeast 
Alaska (Hobbs and Waite 2010). Based on a more conservative density 
estimate of 0.033 harbor porpoise per square km in Southeast Alaska, we 
estimate that approximately 2.6 (.033*78.9) harbor porpoises could 
occur daily within the 78.9 square km (Table 8) Level B harassment 
zone. Therefore: 2.6 harbor porpoises per day * 93 days of potential 
exposure = 242 potential exposures.
Dall's Porpoises
    Dall's porpoise are non-migratory; therefore, our exposure 
estimates are not dependent on season. Based on anecdotal evidence 
citing rare occurrences of the species in the action area, we 
anticipate approximately one observation of a Dall's porpoise pod in 
the Level B harassment zone each week during construction (Lewis, S., 
pers. comm.). Based on an average pod size of 3.7 (Wade et al., 2003), 
we estimate 49 Dall's porpoise could be exposed to Level B harassment 
noise during the 93 day construction period (i.e., 3.7 individuals per 
week * 13.2 weeks of potential exposure = 48.84 (rounded up to 49) 
total potential exposures).
Killer Whales
    Local marine mammal experts indicate that approximately one killer 
whale pod is observed in Tenakee Inlet each month, year-round (Lewis, 
S., pers. comm.). It is assumed that all three killer whale stocks are 
equally likely to occur in the area because no data exist on relative 
abundance of the three stocks in Tenakee Inlet. The exposure estimate 
is conservatively based on a resident pod size, which has been 
quantified and is known to be larger than other stocks. Resident killer 
whales occur in a mean group size of 19.3 during the fall in southeast 
Alaska (Dahlheim et al., 2009). Therefore, we assume that a total of 
approximately 60 killer whales could be exposed to Level B harassment 
over the course of the project (i.e., [19.3 individuals per pod * 1 
pods per month] * 3.1 months = 59.83 [rounded up to 60]). Since there 
are no data that exist for killer stocks in Tenakee Inlet, 60 Level B 
takes were applied to each stock.
    Humpback whales are present in Tenakee Inlet year-round. Local 
experts indicate that as many as 12 humpback whales are present on some 
days from spring through fall, with lower numbers during the winter (S. 
Lewis and M. Dahlheim, pers. comm.). We conservatively estimate that 
half of those, or six individuals on average, could be exposed to Level 
B harassment during each day of pile installation and removal, 
therefore:

6 humpback whales per day * 93 days of exposure = 558 potential 
exposures.
Minke Whales
    Minke whales may be present in Tenakee Inlet year-round. Their 
abundance throughout southeast Alaska is very low, and anecdotal 
reports have not included minke whales near the project area. However, 
minke whales are distributed throughout a wide variety of habitats and 
could occur near the project area. Therefore, we conservatively 
estimate that one minke whale could be exposed to Level B harassment 
each month during construction or a total of three minke whales during 
the 93-day construction period.

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.
    In addition to the measures described later in this section, 
ADOT&PF will employ the following standard mitigation measures:
     Conduct briefings between construction supervisors and 
crews and the marine mammal monitoring team prior to the start of all 
pile driving activity, and when new personnel join the work, to explain 
responsibilities, communication procedures, marine mammal monitoring 
protocol, and operational procedures;
     For in-water heavy machinery work other than pile driving 
(e.g., standard barges, tug boats), if a marine mammal comes within 10 
m, operations shall cease and vessels shall reduce speed to the minimum 
level required to maintain steerage and safe working conditions. This 
type of work could include the following activities: (1) Movement of 
the barge to the pile location; or (2) positioning of the pile on the 
substrate via a crane (i.e., stabbing the pile);
     Work may only occur during daylight hours, when visual 
monitoring of marine mammals can be conducted;
     For those marine mammals for which Level B take has not 
been requested, in-water pile installation/removal and drilling will 
shut down immediately when the animals are sighted;
     If Level B take reaches the authorized limit for an 
authorized species, pile installation will be stopped as these species 
approach the Level B zone to avoid additional take of them.
    The following measures would apply to ADOT&PFs mitigation 
requirements:
    Establishment of Shutdown Zone for Level A--For all pile driving/
removal and drilling activities, ADOT&PF will establish a shutdown 
zone. The purpose of a shutdown zone is generally to define an area 
within which shutdown of activity would occur upon sighting of a marine 
mammal (or in anticipation of an animal entering the defined area). A 
conservative shutdown zone of 100 meters will be used during monitoring 
to prevent any form of incidental Level A exposure for most species. 
However, during impact installation of 24-inch

[[Page 12172]]

and 30-inch steel piles at a frequency of 2 or 3 piles per day, the 
Level A harassment zone exceeds the 100-meter shutdown zone for low- 
and high-frequency cetaceans (i.e., humpback whales, harbor porpoises, 
and Dall's porpoises; see Table 7). During these activities, PSOs will 
implement a 200-meter shutdown zone to avoid take of harbor porpoises, 
Dall's porpoises, minke whales, and humpback whales (low- and high-
frequency cetaceans). The placement of PSOs during all pile driving and 
drilling activities (described in detail in the Proposed Monitoring and 
Reporting Section) will ensure that the 200-meter shutdown zone is 
visible during impact installation of 24-inch and 30-inch steel piles 
at a frequency of two or three piles per day. Nonetheless, a 100-meter 
shutdown will be implemented for Steller sea lions, harbor seals, and 
killer whales during all activities.
    Establishment of Monitoring Zones for Level B--ADOT&PF will 
establish Level B disturbance zones or zones of influence (ZOI) which 
are areas where SPLs are equal to or exceed the 160 dB rms threshold 
for impact driving and the 120 dB rms threshold during vibratory 
driving and drilling. Monitoring zones provide utility for observing by 
establishing monitoring protocols for areas adjacent to the shutdown 
zones. Monitoring zones enable observers to be aware of and communicate 
the presence of marine mammals in the project area outside the shutdown 
zone and thus prepare for a potential cease of activity should the 
animal enter the shutdown zone. The Level B zones are depicted in Table 
7. As shown, the largest Level B zone is equal to 78.9 km\2\, making it 
impossible for the PSOs to view the entire harassment area. Due to 
this, Level B exposures will be recorded and extrapolated based upon 
the number of observed take and the percentage of the Level B zone that 
was not visible.
    Soft Start--The use of a soft-start procedure are believed to 
provide additional protection to marine mammals by providing warning 
and/or giving marine mammals a chance to leave the area prior to the 
hammer operating at full capacity. For impact pile driving, contractors 
will be required to provide an initial set of strikes from the hammer 
at 40 percent energy, each strike followed by no less than a 30-second 
waiting period. This procedure will be conducted a total of three times 
before impact pile driving begins. Soft Start is not required during 
vibratory pile driving and removal activities.
    Pre-Activity Monitoring--Prior to the start of daily in-water 
construction activity, or whenever a break in pile driving of 30 
minutes or longer occurs, the observer will observe the shutdown and 
monitoring zones for a period of 30 minutes. The shutdown zone will be 
cleared when a marine mammal has not been observed within the zone for 
that 30-minute period. If a marine mammal is observed within the 
shutdown zone, a soft-start cannot proceed until the animal has left 
the zone or has not been observed for 30 minutes (for cetaceans) and 15 
minutes (for pinnipeds). If the Level B harassment zone has been 
observed for 30 minutes and non-permitted species are not present 
within the zone, soft start procedures can commence and work can 
continue even if visibility becomes impaired within the Level B zone. 
When a marine mammal permitted for Level B take is present in the Level 
B harassment zone, piling activities may begin and Level B take will be 
recorded. As stated above, if the entire Level B zone is not visible at 
the start of construction, piling or drilling activities can begin. If 
work ceases for more than 30 minutes, the pre-activity monitoring of 
both the Level B and shutdown zone will commence.

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

Visual Monitoring

    Monitoring would be conducted 30 minutes before, during, and 30 
minutes after pile driving and removal activities. In addition, 
observers shall record all incidents of marine mammal occurrence, 
regardless of distance from activity, and shall document any behavioral 
reactions in concert with distance from piles being driven or removed. 
Pile driving activities include the time to install or remove a single 
pile or series of piles, as long as the time elapsed between uses of 
the pile driving equipment is no more than thirty minutes.
    PSOs would be land-based observers. A primary PSO would be placed 
at the terminal where pile driving would occur. A second observer would 
range the uplands on foot or by ATV via Tenakee Ave., and go from Grave 
Point east of the harbor up and west of the project site to get a full 
view of the Level A zone and as much of the Level B zone as possible. 
PSOs would scan the waters using binoculars, and/or spotting scopes, 
and would use a handheld GPS or range-finder device to verify the 
distance to each sighting from the project site. All PSOs would be 
trained in marine mammal identification and behaviors and are required 
to have no other project-related tasks while conducting monitoring. In 
addition, monitoring will be conducted by qualified observers, who will 
be placed at the best vantage point(s) practicable to monitor for 
marine mammals and implement shutdown/delay procedures when applicable 
by calling for the shutdown to the hammer operator. Qualified observers 
are trained and/or experienced professionals, with the following 
minimum qualifications:

[[Page 12173]]

     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.
     Independent observers (i.e., not construction personnel).
     Observers must have their CVs/resumes submitted to and 
approved by NMFS.
     Advanced education in biological science or related field 
(i.e., undergraduate degree or higher). Observers may substitute 
education or training for experience.
     Experience and ability to conduct field observations and 
collect data according to assigned protocols (this may include academic 
experience).
     At least one observer must have prior experience working 
as an observer.
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors.
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations.
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates and times when in-water construction 
activities were suspended to avoid potential incidental injury from 
construction sound of marine mammals observed within a defined shutdown 
zone; and marine mammal behavior.
     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.
    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. It will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated PSO data 
sheets. Specifically, the report must include:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Weather parameters (e.g., percent cover, visibility);
     Water conditions (e.g., sea state, tide state);
     Species, numbers, and, if possible, sex and age class of 
marine mammals;
     Description of any observable marine mammal behavior 
patterns, including bearing and direction of travel and distance from 
pile driving activity;
     Distance from pile driving activities to marine mammals 
and distance from the marine mammals to the observation point;
     Locations of all marine mammal observations; and
     Other human activity in the area.
    If no comments are received from NMFS within 30 days, the draft 
final report will constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury, serious injury or mortality, ADOT&PF 
would immediately cease the specified activities and report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, and the Alaska Regional Stranding 
Coordinator. The report would include the following information:
     Description of the incident;
     Environmental conditions (e.g., Beaufort sea state, 
visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with ADOT&PF to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. ADOT&PF would not be able 
to resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that ADOT&PF discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition as described in the next paragraph), 
ADOT&PF would immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the NMFS Alaska Stranding Hotline and/or by email to the Alaska 
Regional Stranding Coordinator. The report would include the same 
information identified in the paragraph above. Activities would be able 
to continue while NMFS reviews the circumstances of the incident. NMFS 
would work with ADOT&PF to determine whether modifications in the 
activities are appropriate.
    In the event that ADOT&PF discovers an injured or dead marine 
mammal and the lead PSO determines that the injury or death is not 
associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), ADOT&PF would report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or 
by email to the Alaska Regional Stranding Coordinator, within 24 hours 
of the discovery. ADOT&PF would provide photographs, video footage (if 
available), or other documentation of the stranded animal sighting to 
NMFS and the Marine Mammal Stranding Network.

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).

[[Page 12174]]

    As stated in the proposed mitigation section, shutdown zones equal 
to or exceeding Level A isopleths shown in Table 7 will be implemented, 
and in this case, Level A take is not anticipated nor authorized. 
Behavioral responses of marine mammals to pile driving and removal at 
the ferry terminal, if any, are expected to be mild and temporary. 
Marine mammals within the Level B harassment zone may not show any 
visual cues they are disturbed by activities (as noted during 
modification to the Kodiak Ferry Dock) or could become alert, avoid the 
area, leave the area, or display other mild responses that are not 
observable such as changes in vocalization patterns. Given the short 
duration of noise-generating activities per day and that pile driving, 
removal, and drilling would occur for 93 days, any harassment would be 
temporary. In addition, the project was designed with relatively small-
diameter piles, which will avoid the elevated noise impacts associated 
with larger piles. In addition, there are no known biologically 
important areas near the project zone that would be moderately or 
significantly impacted by the construction activities. The region of 
Tenakee Inlet where the project will take place is located in a 
developed area with regular marine vessel traffic. Although there is a 
harbor seal haulout approximately one kilometer south of the project 
site, it would not be located within the project's Level B zone.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality is anticipated or authorized.
     There are no known biologically important areas within the 
project area.
     ADOT&PF would implement mitigation measures such as 
vibratory driving piles to the maximum extent practicable, soft-starts, 
and shut downs.
     Monitoring reports from similar work in Alaska have 
documented little to no effect on individuals of the same species 
impacted by the specified activities.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Section 101(a)(5)(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. Additionally, other qualitative factors may 
be considered in the analysis, such as the temporal or spatial scale of 
the activities.
    Overall, ADOT&PF proposes 15,566 total Level B takes of these 
marine mammals. Table 9 below shows take as a percent of population for 
each of the species listed above.

                   Table 9--Summary of the Estimated Numbers of Marine Mammals Potentially Exposed to Level B Harassment Sound Levels
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Proposed number of exposures to    Proposed number of individuals
            Species                   DPS/stock       level B harassment total and by    potentially exposed to level B        Stock        Percent of
                                                                   stock                           harassment                abundance    population \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steller sea lion...............  Eastern DPS.......  5,351............................  115 individuals.................          41,638            <0.3
                                 Western DPS.......  1,159............................  25 individuals..................          53,303            <0.1
Harbor seal....................  Glacier Bay/Icy     8,144............................  259 individuals.................           7,210             3.6
                                  Strait.
Harbor porpoise................  Southeast Alaska..  242..............................  242.............................             975            24.8
Dall's porpoise................  Alaska............  49...............................  49..............................          83,400            <0.1
Killer whale...................  West Coast          60...............................  60..............................             243            24.7
                                  transient.         60...............................  60..............................           2,347             2.6
                                 Alaska resident...  60...............................  60..............................             290            20.7
                                 Northern Resident.
Humpback whale.................  Mexico DPS/Central  558..............................  558.............................          10,103             5.5
                                  North Pacific.
Minke whale....................  Alaska............  3................................  3...............................             N/A             N/A
                                ------------------------------------------------------------------------------------------------------------------------
    Total......................  ..................  15,686...........................  1,434...........................             N/A             N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ The percent of population is based on the proportion of take that is expected to occur from each stock based on abundance (see Table 3). Killer
  whale stocks are assumed to be equally likely to occur.
N/A: Not Applicable or no stock population assessment is available.

    Table 9 presents the number of animals that could be exposed to 
received noise levels causing Level B harassment for the proposed work 
at the Tenakee Springs Ferry Terminal. Our analysis shows that less 
than 25 percent of each affected stock could be taken by harassment. 
Therefore, the numbers of animals authorized to be taken for all 
species would be considered small relative to the relevant stocks or 
populations even if each estimated taking occurred to a new 
individual--an extremely unlikely scenario. For pinnipeds, especially 
harbor seals and Steller sea lions, occurring in the vicinity of the 
project site, there will almost certainly be some overlap in 
individuals present day-to-day, and these takes are likely to occur 
only within some small portion of the overall regional stock. For 
harbor porpoise, the abundance estimates used in the percentage of 
population were taken from inland Southeast Alaska waters. These 
abundance estimates have not been corrected for g(0) and are likely 
conservative, therefore it is expected for the proposed percentage of 
population that will be taken to be overestimated. In addition, high 
percentage totals for northern resident (20.7 percent) and western 
transient (24.7 percent) killer whales were based on the possibility 
that all 60 takes for killer whales would

[[Page 12175]]

occur for each stock, which is a highly unlikely scenario.
    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

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, 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. The 
proposed project is not known to occur in an important subsistence 
hunting area. It is a developed area with regular marine vessel 
traffic. However, DOT&PF plans to provide advanced public notice of 
construction activities to reduce construction impacts on local 
residents, ferry travelers, adjacent businesses, and other users of the 
Tenakee Springs ferry terminal and nearby areas. This will include 
notification to local Alaska Native tribes that may have members who 
hunt marine mammals for subsistence. Of the marine mammals considered 
in this IHA application, only harbor seals are known to be used for 
subsistence in the project area. If any tribes express concerns 
regarding project impacts to subsistence hunting of marine mammals, 
further communication between will take place, including provision of 
any project information, and clarification of any mitigation and 
minimization measures that may reduce potential impacts to marine 
mammals.
    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 ADOT&PF's 
proposed activities.

Endangered Species Act (ESA)

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

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to ADOT&PF for conducting piling and drilling activities 
associated with improvements at the Tenakee Springs city dock and ferry 
terminal, in Tenakee Springs, Alaska provided the previously mentioned 
mitigation, monitoring, and reporting requirements are incorporated. 
This section contains a draft of the IHA itself. The wording contained 
in this section is proposed for inclusion in the IHA (if issued).
    1. This Incidental Harassment Authorization (IHA) is valid from 
June 1, 2019 to May 31, 2020.
    2. This IHA is valid only for in-water construction activities 
associated with improvements at the Tenakee Springs city dock and ferry 
terminal, in Tenakee Springs, Alaska.
    3. General Conditions.
    (a) A copy of this IHA must be in the possession of the ADOT&PF, 
its designees, work crew, and marine mammal monitoring personnel 
operating under the authority of this IHA.
    (b) The species authorized for taking are humpback whale (Megaptera 
novaeangliae), killer whale (Orcinus orca), Harbor porpoise (Phocoena 
phocoena), Dall's porpoise (Phocoenoides dalli), Steller sea lion 
(Eumetopias jubatus), and harbor seal (Phoca vitulina) and minke whale 
(Balaenoptera acutorostrata).
    (c) The taking, by Level B harassment only, is limited to the 
species/stocks listed in condition 3(b). See Table 1 for numbers of 
take authorized.
    (d) For those marine mammals for which Level B take has not been 
requested, in-water pile installation/removal and drilling shall shut 
down immediately when the animals are sighted.
    (e) The taking by injury (Level A harassment), serious injury, or 
death of any of the species listed in condition 3(b) of the 
Authorization or any taking of any other species of marine mammal is 
prohibited and may result in the modification, suspension, or 
revocation of this IHA.
    (f) ADOT&PF shall conduct briefings between construction 
supervisors and crews, marine mammal monitoring team, acoustical 
monitoring team, and ADOT&PF staff prior to the start of all piling and 
drilling activities, and when new personnel join the work, in order to 
explain responsibilities, communication procedures, marine mammal 
monitoring protocol, and operational procedures.
    (g) Work may only occur during daylight hours, when visual 
monitoring of marine mammals can be conducted.
    4. Mitigation Measures.
    The holder of this Authorization is required to implement the 
following mitigation measures:
    (a) Shutdown Measures.
    (i) For all pile driving/removal and drilling activities, ADOT&PF 
shall implement shutdown measures in which operations shall cease if a 
marine mammal enters or approaches a shutdown zone for which it is not 
permitted to be in during piling or drilling operations. Shutdown zones 
are defined below.
    (ii) For all impact pile driving, vibratory pile driving/removal, 
and drilling the ADOT&PF shall implement a minimum shutdown zone of 100 
meters around each pile (undergoing piling/drilling activities) for all 
species authorized for Level B take.
    (iii) ADOT&PF shall implement a 200-meter radius shutdown zone for 
high- and low-frequency cetaceans (harbor porpoises, Dall's porpoises, 
minke whales, and humpback whales) during impact installation of 24-
inch and 30-inch steel piles at a frequency of two or three piles per 
day.
    (iv) ADOT&PF shall implement shutdown measures if the number of any 
allotted marine mammal Level B takes reaches the limit under the IHA 
and if such marine mammals are sighted within the vicinity of the 
project area and are approaching their respective Level A or Level B 
harassment zone.
    (v) If a marine mammal comes within 10 meters of in-water, heavy 
machinery work other than pile driving or drilling (e.g., standard 
barges, tugboats), operations shall cease and vessels shall reduce 
speed to the minimum level required to maintain steerage and safe 
working conditions.

[[Page 12176]]

    (b) ADOT&PF shall establish Level A and Level B harassment zones as 
shown in Tables 2 and 3.
    (c) Soft Start for Impact Pile Driving
    (i) At the start of any pile driving activities or when there has 
been downtime of 30 minutes or more without impact pile driving, the 
contractor shall initiate the driving with ramp-up procedures described 
below.
    (ii) Soft start for impact hammers requires contractors to provide 
an initial set of strikes from the impact hammer at 40 percent energy, 
followed by no less than a 30-second waiting period. This procedure 
shall be conducted three times before impact pile driving begins.
    (d) Use the minimum hammer energy needed to install piles.
    (e) Drive piles with a vibratory hammer to the maximum extent 
practicable.
    5. Monitoring.
    The holder of this Authorization is required to conduct marine 
mammal monitoring during pile driving/removal and drilling activities. 
Monitoring and reporting shall be conducted in accordance with the 
Monitoring Plan.
    (a) Pre-Activity Monitoring.
    (i) Prior to the start of daily in-water construction activity, or 
whenever a break in pile driving of 30 minutes or longer occurs, the 
observer(s) shall observe the shutdown and monitoring zones for a 
period of 30 minutes.
    (ii) The shutdown zone shall be cleared when a marine mammal has 
not been observed within that zone for that 30-minute period.
    (iii) If a marine mammal is observed within the shutdown zone, a 
soft-start can proceed if the animal is observed leaving the zone or 
has not been observed for 30 minutes (for cetaceans) or 15 minutes (for 
pinnipeds), even if visibility of Level B zone is impaired.
    (iv) If the Level B harassment zone has been observed for 30 
minutes and non-permitted species are not present within the zone, in-
water construction can commence and work can continue even if 
visibility becomes impaired within the Level B zone.
    (v) When a marine mammal permitted for Level B take is present in 
the Level B harassment zone, piling and drilling activities may begin 
and or continue and Level B take shall be recorded.
    (vi) If the entire Level B zone is not visible while work 
continues, exposures shall be recorded and extrapolated based upon the 
amount of total observed exposures and the percentage of the Level B 
zone that was not visible.
    (b) Monitoring shall be conducted by qualified protected species 
observers (PSOs), with minimum qualifications as described previously 
in the Monitoring and Reporting section.
    (i) Two observers shall be on site to actively observe the shutdown 
and disturbance zones during all pile driving, removal, and drilling.
    (ii) Observers shall use their naked eye with the aid of 
binoculars, and/or a spotting scope during all pile driving and 
extraction activities.
    (iii) Monitoring location(s) shall be identified with the following 
characteristics:
    1. Unobstructed view of pile being driven;
    2. Unobstructed view of all water within the Level A zone (if 
applicable) and as much of the Level B harassment zone as possible for 
piles being driven.
    (c) If waters exceed a sea-state, which restricts the PSOs ability 
to observe within the marine mammal shutdown zone (e.g., excessive wind 
or fog), pile installation and removal shall cease. Pile driving shall 
not be initiated until the entire shutdown zone is visible.
    (d) Marine mammal location shall be determined using a rangefinder 
and a GPS or compass.
    (e) Ongoing in-water pile installation may be continued during 
periods when conditions such as low light, darkness, high sea state, 
fog, ice, rain, glare, or other conditions prevent effective marine 
mammal monitoring of the entire Level B harassment zone. PSOs would 
continue to monitor the visible portion of the Level B harassment zone 
throughout the duration of driving activities.
    (f) Post-construction monitoring shall be conducted for 30 minutes 
beyond the cessation of piling and drilling activities at end of day.
    6. Reporting.
    The holder of this Authorization is required to:
    (a) Submit a draft report on all monitoring conducted under the IHA 
within ninety calendar days of the completion of marine mammal 
monitoring. This report shall detail the monitoring protocol, summarize 
the data recorded during monitoring, and estimate the number of marine 
mammals that may have been harassed, including the total number 
extrapolated from observed animals across the entirety of relevant 
monitoring zones A final report shall be prepared and submitted within 
thirty days following resolution of comments on the draft report from 
NMFS. This report must contain the following:
    (i) Date and time a monitored activity begins or ends;
    (ii) Construction activities occurring during each observation 
period;
    (iii) Record of implementation of shutdowns, including the distance 
of animals to the pile and description of specific actions that ensued 
and resulting behavior of the animal, if any;
    (iv) Weather parameters (e.g., percent cover, visibility);
    (v) Water conditions (e.g., sea state, tide state);
    (vi) Species, numbers, and, if possible, sex and age class of 
marine mammals;
    (vii) Description of any observable marine mammal behavior 
patterns;
    (viii) Distance from pile driving activities to marine mammals and 
distance from the marine mammals to the observation point;
    (ix) Locations of all marine mammal observations; and
    (x) Other human activity in the area.
    (b) Reporting injured or dead marine mammals:
    (i) In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by this IHA, 
such as an injury (Level A harassment), serious injury, or mortality, 
ADOT&PF shall immediately cease the specified activities and report the 
incident to the Office of Protected Resources (301-427-8401), NMFS, and 
the Alaska Regional Stranding Coordinator (907-271-1332), NMFS. The 
report must include the following information:
    1. Time and date of the incident;
    2. Description of the incident;
    3. Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    4. Description of all marine mammal observations and active sound 
source use in the 24 hours preceding the incident;
    5. Species identification or description of the animal(s) involved;
    6. Fate of the animal(s); and
    7. Photographs or video footage of the animal(s).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS shall work with ADOT&PF to 
determine what measures are necessary to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. ADOT&PF may not 
resume their activities until notified by NMFS.
    (ii) In the event that ADOT&PF discovers an injured or dead marine 
mammal, and the lead observer determines that the cause of the injury 
or death is unknown and the death is relatively recent (e.g., in less 
than a moderate state of decomposition), ADOT&PF shall immediately 
report the incident to the Office of Protected Resources, NMFS, and the 
Alaska Regional Stranding Coordinator, NMFS.

[[Page 12177]]

    The report must include the same information identified in 6(b)(i) 
of this IHA. Activities may continue while NMFS reviews the 
circumstances of the incident. NMFS shall work with ADOT&PF to 
determine whether additional mitigation measures or modifications to 
the activities are appropriate.
    (iii) In the event that ADOT&PF discovers an injured or dead marine 
mammal, and the lead observer determines that the injury or death is 
not associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), ADOT&PF shall report the incident 
to the Office of Protected Resources, NMFS, and the Alaska Regional 
Stranding Coordinator, NMFS, within 24 hours of the discovery. ADOT&PF 
shall provide photographs, video footage, or other documentation of the 
stranded animal sighting to NMFS.
    7. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein, or if 
NMFS determines the authorized taking is having more than a negligible 
impact on the species or stock of affected marine mammals.

                               Table 1--Authorized Take Numbers, by Species/Stocks
----------------------------------------------------------------------------------------------------------------
                    Species                                 DPS/stock              Level A takes   Level B takes
----------------------------------------------------------------------------------------------------------------
Steller sea...................................  Eastern DPS.....................               0             115
lion..........................................  Western DPS.....................                              25
Harbor seal...................................  Glacier Bay/Icy Strait..........               0             259
Harbor porpoise...............................  Southeast Alaska................               0             242
Dall's porpoise...............................  Alaska..........................               0              49
Killer whale..................................  West Coast transient............               0              60
                                                Alaska resident.................                              60
                                                Northern Resident...............                              60
Humpback whale................................  Mexico DPS/Central North Pacific               0             558
Minke whale...................................  Alaska..........................  ..............               3
                                               -----------------------------------------------------------------
    Total.....................................  ................................               0           1,431
----------------------------------------------------------------------------------------------------------------


                     Table 2--Calculated Distances to Level A and Level B Harassment Isopleths During Pile Installation and Removal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Level A harassment zone (meters)            Level B
                                                                                 Piles    ---------------------------------------------  harassment zone
               Type of pile                             Activity               installed           Cetaceans              Pinnipeds         (meters),
                                                                               or removed ---------------------------------------------   cetaceans and
                                                                                per day       LF       MF       HF       PW       OW        pinnipeds
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                   Vibratory (120 dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
30-inch steel............................  Install..........................            3       11        1       16        7        1            10,000
24-inch steel, 20-inch steel, 18-inch      Install..........................            3        6        1        9        4        1             5,412
 steel.
18-inch steel, 16-inch steel.............  Remove...........................           10       13        2       19        8        1             5,412
14-inch steel, 14-inch timber, 12.75-inch  Remove...........................           10        5        1        8        3        1             2,154
 steel.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Drilling (120 dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
30-inch steel, 20-inch steel.............  Install..........................            3       55        5       81       34        3            10,000
24-inch steel, 18-inch steel.............  Install..........................            3       42        4       62       26        2            10,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Impact (160 dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
30-inch steel............................  Proofing.........................            1       70        3       82       37        3             2,057
                                           .................................            2      110        4      131       59        5  ................
                                           .................................            3      144        6      171       77        6  ................
24-inch steel............................  Proofing.........................            1       71        3       85       38        3             1,585
                                           .................................            2      113        4      135       61        5  ................
                                           .................................            3      148        6      176       79        6  ................
20-inch steel............................  Proofing.........................            3       64        3       76       34        3               584
18-inch steel............................  Proofing.........................            3       <1       <1       <1       <1       <1                 7
14-inch timber...........................  Install..........................           10       <1       <1       <1       <1       <1                 7
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 12178]]


Table 3--Calculated Areas Ensonified Within Level B Harassment Isopleths
                  During Pile Installation and Removal
------------------------------------------------------------------------
                                                             Level B
                                                         harassment zone
           Type of pile                  Activity           (km \2\),
                                                          cetaceans and
                                                            pinnipeds
------------------------------------------------------------------------
                           Vibratory (120 dB)
------------------------------------------------------------------------
30-inch steel....................  Install............              78.9
24-, 20-, 18-, and 16-inch steel.  Install............              45.3
14-, 12.75-inch steel, and 14-     Remove.............               7.3
 inch timber.
------------------------------------------------------------------------
                            Drilling (120 dB)
------------------------------------------------------------------------
30-, 24-, 20-, and 18-inch steel.  Install............              78.9
------------------------------------------------------------------------
                             Impact (160 dB)
------------------------------------------------------------------------
30-inch steel....................  Proofing...........               6.7
24-inch steel....................  Proofing...........               4.0
20-inch steel....................  Proofing...........               0.6
18-inch steel....................  Proofing...........              <0.1
14-inch timber...................  Install............              <0.1
------------------------------------------------------------------------

Request for Public Comments

    We request comment on our analyses, the draft authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed 
[action]. Please include with your comments any supporting data or 
literature citations to help inform our final decision on the request 
for MMPA authorization.

    Dated: March 14, 2018.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2018-05559 Filed 3-19-18; 8:45 am]
BILLING CODE 3510-22-P