Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Biorka Island Dock Replacement Project, 41229-41255 [2017-18347]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 82, Number 167 (Wednesday, August 30, 2017)]
[Notices]
[Pages 41229-41255]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-18347]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XF540


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Biorka Island Dock Replacement 
Project

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

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

-----------------------------------------------------------------------

SUMMARY: NMFS has received a request from the Federal Aviation 
Administration (FAA) for authorization to take marine mammals 
incidental to construction activities as part of its Biorka Island Dock 
Replacement Project. Pursuant to the Marine Mammal Protection Act 
(MMPA), NMFS is requesting public comment on its proposal to issue an 
incidental harassment authorization (IHA) to the FAA to incidentally 
take marine mammals, by Level A and Level B harassment, during the 
specified activity. NMFS will consider public comments prior to making 
any final decision on the issuance of the requested MMPA authorizations 
and agency responses will be summarized in the final notice of our 
decision.

DATES: Comments and information must be received no later than 
September 29, 2017.

ADDRESSES: Comments on this proposal 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 ITP.mccue@noaa.gov.
    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.html 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: Laura McCue, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the applications 
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 Incidental Take Authorization (ITA) 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 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 (NEPA) 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 environmental 
consequences 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 March 31, 2017, NMFS received a request from the FAA for an IHA 
to take marine mammals incidental to pile driving and removal and down 
the hole (DTH) drilling in association with the Biorka Island Dock 
Replacement Project (Project) in Symonds Bay, Alaska. The FAA's request 
is for take of five species by Level A and Level B harassment. Neither 
the FAA nor NMFS expect mortality to result from this activity and, 
therefore, an IHA is appropriate.
    In-water work associated with the in-water construction is expected 
to be completed within 70 days. This proposed IHA is for the 2018 
construction window (May 1, 2018 through September 30, 2018). This IHA 
would be valid from May 1, 2018, through April 30, 2019.

Description of the Specified Activity

Overview

    The FAA is constructing a replacement dock on Biorka Island in

[[Page 41230]]

Symonds Bay near Sitka, Alaska. The purpose of the Project is to 
improve and maintain the sole point of access to Biorka Island and the 
navigational and weather facilities located on the Island. The existing 
dock is deteriorated and has reached the end of its useful life. 
Regular and repetitive heavy surging seas, along with constant use have 
destroyed the face of the existing floating marine dock, and have 
broken cleats making it difficult to tie a vessel to the existing dock. 
In its present condition, small vessels cannot use the dock to provide 
supplies to facilities on the Island. The existing barge landing area 
is reinforced seasonally by adding fill to the landing at the 
shoreline, which is periodically washed away by storms and wave action. 
The Project would reconstruct the deteriorated existing dock and 
construct an improved barge landing area.

Dates and Duration

    The total Project is expected to require a maximum of 70 days of 
in-water construction activities. In-water activities are limited to 
occurring between May 1 and September 30 of any year to minimize 
impacts to special-status and commercially and biologically important 
fish species. This proposed authorization would be effective from May 
1, 2018 through April 30, 2019.

Specific Geographic Region

    The Project is located approximately 15 miles (24 kilometers (km)) 
southwest of Sitka on the northern shore of Biorka Island on land owned 
by the FAA (see Figure 1-1 of the FAA's application). Biorka Island is 
the most westerly and largest of the Necker Island group on the west 
coast of Baranof Island.
    Symonds Bay is approximately 0.4 miles wide (east to west 
direction). Water depths are less than 66 feet (ft) within 1,300 ft of 
the dock (see Figure 1-2 of the FAA's application). The outer dolphin 
(see Figure 1-4 of the application) would be located in about 20 ft of 
water at mean high water. This is the deepest water depth for all piles 
and, as a precautionary measure, was used as the water depth input for 
acoustic modeling described later in this document.
    On shore at the Project site, bedrock is exposed in many places. 
The overburden varies from zero to about 15 ft deep and consists of 
highly fractured weathered bedrock and includes seams of very soft rock 
or soil. Due to the fractures and seams, it is possible to drive piles 
into this top layer ``Category 1 intensely fractured bedrock.'' Beneath 
the top layer, the rock becomes more intact ``Category II intensely to 
moderately fractured bedrock.'' The seabed composition is important in 
this Project because it determines the pile-driving methods needed to 
achieve the required pile penetration.

Detailed Description of Activities

    The Project consists of removing the existing dock and associated 
infrastructure and constructing a new, modern structure to provide 
continued safe access to Biorka Island facilities. The existing dock is 
a T-shaped, pile-supported structure consisting of a 170-ft long by 16-
ft wide approach trestle with a 51-ft wide by 35-ft long end section. 
The existing infrastructure also includes a 30-ft by 32-ft floating 
dock that is accessed by a 5-ft wide by 50-ft long steel gangway, a 
small 10-ft by 10-ft pre-fabricated building, and an electric hydraulic 
pedestal crane.
    A total of 46 existing piles would be removed (Table 1). The steel 
and timber piles would be pulled out of the substrate directly with a 
crane and sling, by using a vibratory hammer, or with a clamshell 
bucket. The three concrete piles that are located above the high tide 
were cast in place. The concrete piles are set in bedrock and will be 
removed at low tide using standard excavation equipment. Therefore, 
removal of these piles will not produce underwater noise. The 
construction contractor would determine the exact method for concrete 
pile removal.
    The existing deck and other associated infrastructure would also be 
disassembled and removed. The existing 4-ton pedestal crane would be 
salvaged for relocation on the new dock. As necessary, portions of the 
existing rubble mound/breakwater would be removed to provide enough 
clearance for construction and then replaced once the dock has been 
constructed.

                  Table 1--Existing Piles To Be Removed
------------------------------------------------------------------------
                                                                  Size
                     Pile type                       Quantity     (in)
------------------------------------------------------------------------
Concrete..........................................          3         24
Steel.............................................         14          8
                                                            8         10
                                                           14      12.75
Timber............................................          7   14 (\1\)
                                                   ---------------------
    Total.........................................         46
------------------------------------------------------------------------
\1\ tapering to 8.

    Facilities for the new dock consist of three main structures: A 
barge landing platform, a dock/trestle, and two dolphin fenders located 
near the dock outer corners (Figure 1-4 of the FAA's application). For 
these structures, temporary piles would be installed to form a scaffold 
system (i.e., a template) that permits the permanent piles to be 
aligned and controlled. With the exception of the temporary piles, 
which are driven exclusively by vibratory pile driving, the 
installation of all permanent piles requires a combination of pile 
driving methods.
    Construction of the new dock would begin with the erection of a 
temporary template. The construction contractor would determine the 
specific type and size of template piles based on site conditions and 
availability of materials. The template piles would be driven into the 
overburden by vibratory hammer and removed after the permanent piles 
are installed. Table 2 shows the anticipated number of template piles 
for the Project.
    The new trestle approach would be up to 25-ft wide. An 80-ft 
aluminum gangway connecting to a 15-ft wide by 32-ft long small craft 
berthing float would also be constructed (see Figure 1-4 of the FAA's 
application). The face of the dock would be approximately 54-ft long 
and 35-ft wide. Similar to the trestle, steel pipe pilings would 
support a precast concrete deck. Two berthing dolphin fenders would be 
installed, one at each end section of the new dock. These dolphins each 
consist of one 30-in diameter plumb pile and two 18-in diameter batter 
piles. Some piles would require internal tension anchors for increased 
support. A wave barrier, consisting of Z-sheet piles in between steel H 
piles, would be installed at the face of the dock. Pile counts, sizes, 
and other details are shown in Table 2.
    All permanent pipe piles would be installed using a combination of 
vibratory and impact hammering methods to drive the pile into the 
overburden. Pipe piles would then be drilled and socketed into the 
underlying bedrock using DTH hammering/drilling techniques. DTH 
equipment breaks up the rock below the pile while simultaneously 
installing the pile through rock formation. The pile is then set/
confirmed with a few strikes of an impact hammer. Sheet piles would be 
driven into the overburden and set into the top layer of bedrock using 
a combination of vibratory and impact hammering.
    Certain piles would require internal tension anchors. Up to eight 
of the dock piles and all six piles for the dolphins would require 
these internal tension anchors. Each pile with a tension anchor would 
first be drilled, socketed into bedrock, and proof driven with an 
impact hammer as described above for permanent piles. Then a separate 
smaller drill would be used to complete

[[Page 41231]]

an approximately 5-in diameter hole extending about 30- to 40-ft into 
bedrock below the tip of the pile. A steel bar would be grouted into 
this hole. Once the grout sets, a jack would be applied to the top of 
the bar and the tensioned rod would be locked off to plates at the top 
of the pile.
    The wave barrier consisting of steel H piles with Z sheets in 
between is located at the face of the dock. The H piles and Z sheets 
would be initially driven through overlying sediment with a vibratory 
hammer, and set into the bedrock with an impact hammer. The wave 
barrier sheet piling would be driven either singly or in preassembled 
pairs.
    The current barge landing is located northwest of the existing dock 
and is comprised of gravel and cobbles with no formal structure. The 
uplands area on the west end of the trestle would be slightly graded 
into the existing terrestrial approach. The existing barge landing 
would be upgraded to a 30-ft by 90-ft precast concrete plank landing 
placed over fill, with a perimeter constructed of concrete, sheet 
piles, and 18-in steel piles (see Table 2). Similar to the wave 
barrier, the sequence for installing the permanent barge ramp pipe 
piles would begin with advancement through overlying sediment with a 
vibratory hammer, followed by use of an impact hammer to drive the 
piles into bedrock.

                                  Table 2--Temporary and Permanent Pile Details
----------------------------------------------------------------------------------------------------------------
            Component                      Stage                 Type            Quantity            Size
----------------------------------------------------------------------------------------------------------------
Dock 1 2.........................  Template \3\........  Steel H or pipe....              60  12 in.
                                   Permanent...........  Steel pipe.........              43  18 in.
Wave Barrier.....................  Permanent...........  Sheet..............              32  NZ 26.
                                   Permanent...........  Steel H............              16  W40 x 199.
Dolphin Fenders \4\..............  Template \3\........  Steel H or pipe....               4  12 in.
                                   Permanent...........  Steel pipe.........               4  18 in.
                                   Permanent...........  Steel pipe.........               2  30 in.
Barge Landing....................  Template \3\........  Steel H or pipe....              20  12 in.
                                   Permanent...........  Steel pipe.........              35  18 in.
                                   Permanent...........  Sheet..............              34  NZ 26.
                                                                             ----------------
    Total........................  Template \3\........  ...................              84
                                                                             ----------------
                                   Permanent...........  ...................             166
----------------------------------------------------------------------------------------------------------------
\1\ Includes piles for the approach, end section, platform, and floating dock.
\2\ Number of piles for dock is based on 25-ft approach trestle width.
\3\ Noise from installation and removal of the template piles is considered in the analysis, therefore template
  pile count equates to two times 84 or 168 but the actual number of piles to be installed is 84. Template piles
  were assumed to be 12-in. diameter for modeling.
\4\ For two dolphin fender systems.

    Vibratory hammers are commonly used in steel pile driving or 
removal where sediments allow. Generally, the pile is placed into 
position using a choker and crane, and then vibrated between 1,200 and 
2,400 vibrations per minute. The vibrations liquefy the sediment 
surrounding the pile allowing it to penetrate to the required seating 
depth, or to be removed.
    Impact hammers are used to install plastic/steel core, wood, 
concrete, or steel piles. An impact hammer is a steel device that works 
like a piston. The pile is first moved into position and set in the 
proper location using a choker cable or vibratory hammer. The impact 
hammer is held in place by a guide (lead) that aligns the hammer with 
the pile. A heavy piston moves up and down, striking the top of the 
pile and driving it into the substrate. Once the pile is set in place, 
pile installation with an impact hammer can take less than 15 minutes 
under good substrate conditions. However, under poor conditions, such 
as glacial till and bedrock or exceptionally loose material, piles can 
take longer to set.
    The DTH drill/hammer acts on a shoe at the bottom of the pile and 
uses a pulsing mechanism to break up rock below the pile while 
simultaneously installing the pile through the rock formation. Rotating 
bit wings extend below the pile and remove the broken rock fragments as 
the pile advances. The pulsing sounds produced by the DTH hydro-hammer 
method 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). 
Therefore, the pulsing sounds produced by this method are considered 
less harmful than those produced by impact hammer driving. Table 3 
provides a summary of the six methods of construction (``scenarios'') 
used in the modeling of the zone of influence (ZOI)s for the Biorka 
Project.

                         Table 3--Pile Driving Modeling Scenarios for the Biorka Project
----------------------------------------------------------------------------------------------------------------
                                                Vibratory            DTH             Impact
                                           ------------------------------------------------------
                                   Piles                                                  Total     Shift
   Scenario       Description    installed   Hours    Total    Hours    Total    Hours   strikes    (hr)
                                   per day    per     hours     per     hours     per       per
                                              pile   per day    pile   per day    pile     day
----------------------------------------------------------------------------------------------------------
S1...........  Removal of               21     0.33     6.93       NA \1\
                existing piles
                and
                installation/
                removal of
                temporary piles.
                            NA                 6.93
                                                             ---------------------------------------------------
S2...........  Installation of           3  .......     0.99        2        6     0.17       15      7.49
                18-inch pipe
                piles (dock and
                dolphin).
                                                             ---------------------------------------------------
S3...........  Installation of           4  .......     1.32         NA            0.33     2720      2.65
                18-inch pipe
                piles (barge
                landing).
                                                             ---------------------------------------------------

[[Page 41232]]

 
S4...........  Installation of           2  .......     0.66        2        4     0.17       10      4.99
                30-inch pipe
                piles
                (dolphins).
                                                             ---------------------------------------------------
S5...........  Installation of           8  .......     2.64         NA            0.33     5440      5.31
                H piles (dock
                wave barrier).
                                                             ---------------------------------------------------
S6...........  Installation of          12  .......     3.96         NA            0.25     6120      6.96
                sheet piles
                (dock wave
                barrier and
                barge landing).
----------------------------------------------------------------------------------------------------------------
\1\ NA indicates when a pile driving method was not required in a given scenario.

    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see Proposed 
Mitigation and Proposed Monitoring and Reporting).

Description of Marine Mammals in the Area of the Specified Activity

    There are five marine mammal species that may likely transit 
through the waters nearby the Project area, and are expected to 
potentially be taken by the specified activity. These include the 
Steller sea lion (Eumetopias jubatus), harbor seal (Phoca vitulina), 
harbor porpoise (Phocoena phocoena), killer whale (Orcinus orca), and 
humpback whale (Megaptera noviaeangliae). Multiple additional marine 
mammal species may occasionally enter Sitka sound but would not be 
expected to occur in shallow nearshore waters of the action area.
    Sections 3 and 4 of the FAA's application summarize available 
information regarding status and trends, distribution and habitat 
preferences, and behavior and life history, of the potentially affected 
species. Additional information regarding population trends and threats 
may be found in NMFS's Stock Assessment Reports (SAR; 
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 Web site (www.nmfs.noaa.gov/pr/species/mammals/).
    Table 4 lists all species with expected potential for occurrence in 
Symonds Bay and Sitka Sound and summarizes information related to the 
population or stock, including 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 are included here as gross indicators of the status of the 
species and other threats.
    Species that could potentially occur in the proposed survey areas, 
but are not expected to have reasonable potential to be harassed by in-
water construction, are described briefly but omitted from further 
analysis. These include extralimital species, which are species that do 
not normally occur in a given area but for which there are one or more 
occurrence records that are considered beyond the normal range of the 
species. Gray whales are observed in and outside of Sitka Sound during 
their northward spring migration; however, they occur generally north 
and west of the Project area in outer shelf waters of Sitka Sound near 
Kruzof Island during the construction window. Dall's porpoise are 
observed in mid- to outer-shelf coastal waters of Sitka Sound ranging 
to the Gulf of Alaska and are not expected to occur in the Project area 
during the construction window. Pacific white-sided dolphins occur in 
the outer-shelf slope in the Gulf of Alaska, which is outside of the 
Project area. During the construction window, they are considered rare 
in Sitka Sound. Sperm whales generally occur in deeper waters in the 
Gulf of Alaska, which is outside of the Project area. We do not 
anticipate gray whales, Dall's porpoise, Pacific white-sided dolphins, 
or sperm whales to be affected by Project activities; therefore, we do 
not discuss these species further. For status of species, we provide 
information regarding U.S. regulatory status under the MMPA and 
Endangered Species Act (ESA).
    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 area. NMFS's stock 
abundance estimates for most species represent the total estimate of 
individuals within the geographic area, if known, that comprises that 
stock. For some species, this geographic area may extend beyond U.S. 
waters. All managed stocks in this region are assessed in NMFS's U.S. 
Pacific SARs (Muto et al., 2017). All values presented in Table 4 are 
the most recent available at the time of publication and are available 
in the 2016 SARs (Muto et al., 2017).

                                      Table 4--Marine Mammals Potentially Present in the Vicinity of Biorka Island
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                    Relative occurrence
                                                               ESA/MMPA  status;     Stock abundance  (CV,             Annual  M/   in Symonds Bay  and
              Species                         Stock           strategic  (Y/N) \1\    Nmin,  most recent     PBR \3\     SI \4\    Sitka Sound;  season
                                                                                    abundance  survey) \2\                             of occurrence
--------------------------------------------------------------------------------------------------------------------------------------------------------
                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocoenidae (porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor porpoise (Phocoena phocoena)  Southeast Alaska......  -; Y                   11,146 (0.242; n/a;        Undet.         34  Common.
                                                                                     1997).
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 41233]]

 
                            Order Cetartiodactyla--Cetacea--Superfamily Odontoceti (toothed whales, dolphins, and porpoises)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                              Family Delphinidae (dolphins)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Killer whale (Orcinus orca)........  Eastern North Pacific   -; N                   587 (n/a; 587; 2012)..          0          0  Infrequent.
                                      Gulf of Alaska,
                                      Aleutian Island, and
                                      Bering Sea Transient.
                                     West Coast Transient..  -; N                   243 (n/a; 243; 2009)..        2.4          0
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Family Balaenopteridae
--------------------------------------------------------------------------------------------------------------------------------------------------------
Humpback whale \5\ (Megaptera        Central North Pacific   -; Y                   10,103 (0.300; 7,890;          83         24  Likely.
 novaeangliae).                       stock.                                         2006).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Family Otariidae (eared seals and sea lions)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Steller sea lion (Eumetopias         Western...............  E; Y                   49,497 (n/a; 49,497;          297        236  Common.
 jubatus).                                                                           2014).
                                     Eastern...............  -; N                   60,131 (n/a; 36,551;        1,645        108
                                                                                     2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocidae (earless seals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor seal (Phoca vitulina).......  Sitka/Chatham.........  -; N                   14,855 (n/a; 13,212;          155         77  Common.
                                                                                     2011).
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Endangered Species Act (ESA) status: Yes (Y), No (N), Endangered (E), Threatened (T)/Marine Mammal Protection Act (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 (see footnote 3) 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\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For certain stocks, abundance
  estimates are actual counts of animals and there is no associated CV. The most recent abundance survey that is reflected in the abundance estimate is
  presented; there may be more recent surveys that have not yet been incorporated into the estimate.
\3\ Potential biological removal, 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 size (OSP).
\4\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
\5\ The humpback whales considered under the MMPA to be part of this stock could be from any of two different DPSs. In Alaska, it would be expected to
  primarily be whales from the Hawaii DPS but could also be whales from Mexico DPS.

    Below, for those species that are likely to be taken by the 
activities described, we offer a brief introduction to the species and 
relevant stock. We also provide information regarding population trends 
and threats, and describe any information regarding local occurrence.
    In Southeast Alaska, marine mammal distributions and seasonal 
increases in their abundance are strongly influenced by seasonal pre-
spawning and spawning aggregations of forage fish, particularly Pacific 
herring (Clupea pallasii), eulachon (Thaleichthys pacificus) and 
Pacific salmon (Onchorynchus spp.) (Marston et al., 2002, Sigler et 
al., 2004, Womble et al., 2005; USACE 2013). All five species of salmon 
are found in Sitka Sound and are preyed upon by Steller sea lions, 
harbor seals, and killer whales. However, there are no salmon spawning 
streams in the vicinity of the Project or presence of eulachon or 
herring during the construction time period that would tend to 
aggregate foraging marine mammals.
    Herring are the keystone species in Southeast Alaska, especially 
Sitka Sound, serving as a vital link between lower trophic levels, 
including crustaceans and small fish, and higher trophic levels (NMFS 
2014a). Foraging studies of Steller sea lions suggest that during their 
non-breeding season, they forage on seasonally densely aggregated prey 
(Sinclair and Zepplin 2002). In southeast Alaska, Pacific herring 
typically spawn from March to May and attract large numbers of 
predators (Marston et al., 2002, Womble 2003). The relationship between 
humpback whales and Steller sea lions and these ephemeral fish runs is 
so strong in Sitka Sound that the seasonal abundance and distribution 
of marine mammals reflects the distribution of pre-spawning and 
spawning herring, and overwintering aggregations of adult herring in 
Sitka Sound. The largest aggregations of several species of marine 
mammals in the Action Area target Pacific herring during spring and 
again in late fall through the winter. Pacific herring are largely 
absent from Sitka Sound and the Action Area from May, following 
spawning season, until at least October,

[[Page 41234]]

prior to adult overwintering in Sitka Sound (NMFS 2014a).

Steller Sea Lion

    Steller sea lions are divided in to two distinct population 
segments (DPSs): The western DPS (wDPS) and the eastern DPS (eDPS). The 
wDPS is listed as endangered under the ESA. The wDPS breeds on 
rookeries located west of 144[deg] W. in Alaska and Russia, whereas the 
eDPS breeds on rookeries in southeast Alaska through California. The 
majority of Steller sea lions are part of the non-listed eDPS. The best 
available information indicates the eDPS has increased at a rate of 
4.18 percent per year between 1979 and 2010 (Allen and Angliss 2014). 
Steller sea lions range from the North Pacific Rim from northern Japan 
to California, with centers of abundance located in the Gulf of Alaska 
and Aleutian Islands. Large numbers of individuals disperse widely 
outside of the breeding season (late May to early July), thus 
potentially intermixing with animals from other areas to access 
seasonally important prey resources (Allen and Angliss 2014). The 
distinction between western and eastern DPS individuals cannot be 
confirmed unless an animal has been marked, and since guidance on how 
to otherwise distinguish between the two DPSs is not available, for 
this IHA it is assumed that 50 percent of the Steller sea lions 
observed in the Project area are from each DPS.
    Critical habitat for Steller sea lions includes designated haulouts 
within the range of the eDPS, and all marine waters within 20 nautical 
miles of rookeries and haulouts within the breeding range of the wDPS 
and within three special aquatic foraging areas in Alaska (NMFS 1993). 
In identifying aquatic habitats as part of critical habitat, NMFS 
specifically highlighted several components of such habitats: Nearshore 
waters around rookeries and haulouts; traditional rafting sites; food 
resources; and foraging habitats. Adequate food resources are an 
essential feature of the Steller sea lion's aquatic habitat (NMFS 
1993). The closest haulout/rookery to the Project area that has been 
designated as a Steller sea lion critical habitat is listed as ``Biorka 
Island'' in the critical habitat descriptions. However, the haulout is 
actually on Kaiuchali Island, a three-acre rocky islet located slightly 
less than one mile southwest of Biorka Island, outside of the ZOI for 
this project.
    This species occurs in coastal and nearshore habitats of Sitka 
Sound, and forage on herring and salmon throughout the Sound. Both DPSs 
occur in the Project area on a year-round basis. Kaiuchali Island is 
used as a sea lion rookery in spring-summer and as a haulout during the 
non-breeding seasons (Fritz et al. 2016). Based on results of recent 
aerial surveys, there has been an increase of sea lions that use 
Kaiuchali Island during both the breeding and non-breeding seasons. In 
June 2013, Fritz et al., (2016) documented 22 individuals, none of 
which were pups. In June 2015, the same study recorded 77 Steller sea 
lions, including one pup. This limited information shows an increase in 
the numbers of animals at this location and indicates that the site has 
become a recently-established eDPS rookery.
    The breeding season for Steller sea lions does not overlap with 
proposed summer construction activity at the Project site, and the 
location of the rookery at Kaiuchali Island is outside the Project 
area, opposite Biorka Island. The late fall and overwintering 
aggregation of adult herring results in hundreds of animals using 
Kaiuchali Island as a haulout during this period; however, the 
construction period for the proposed Project would not overlap with the 
overwintering aggregations of sea lions. Steller sea lions are present 
in Sitka Sound in very low numbers over the summer months when 
construction is planned, during the interval between herring spawning 
and the return of adult herring to Sitka Sound. Prey availability for 
Steller sea lions in Sitka Sound is limited during this period as 
compared to other seasons, and they are generally only observed by the 
whale watch industry as individuals or in small groups of three to five 
animals. During this period, sea lions tend to forage in the vicinity 
of recreational and commercial fishing vessels, or scavenge in very 
shallow waters near the Sitka town docks when the vessels return from 
fishing.

Harbor Seal

    Harbor seals inhabit coastal and estuarine waters off Alaska. 
Harbor seals in Southeast Alaska are considered non-migratory with 
local movements attributed to factors such as prey availability, 
weather, and reproduction. In 2010, NMFS identified 12 stocks of harbor 
seals in Alaska based on genetic structure (Allen and Angliss 2015). 
The Sitka/Chatham (S/C) stock is genetically distinct and believed to 
be year-round residents of the region. Although generally solitary in 
the water, harbor seals congregate at haulouts to rest, socialize, 
breed, and molt. Habitats used as haul-out sites include tidal rocks, 
bayflats, sandbars, and sandy beaches (Zeiner et al., 1990).
    Harbor seals are opportunistic feeders that forage on fish and 
invertebrates and often adjust their distribution to take advantage of 
locally and seasonally abundant prey. Aggregations of adult herring 
during spring pre-spawning and spawning runs, and again from October 
throughout the winter, are a very important seasonal prey species for 
harbor seals in Sitka Sound. The minimum count of harbor seals within 
Sitka Sound during the 2011 aerial survey was approximately 900 
individuals occupying 25 haulout locations (unpublished data from MML 
dataset). The largest count of seals in Sitka Sound (n = 745) during 
the 2011 survey occurred at several adjacent rocky outcroppings and 
islands (Vitskari Rocks, Vitskari Island and Low Island) located 
approximately 15 miles (24 km) north of the Project site in 
northcentral Sitka Sound inside Kruzof Island. This is outside of the 
Project Area. Prey species moving into Sitka Sound from the Gulf of 
Alaska move past these islands so pinnipeds aggregate at these rocks to 
forage. There are six haul-out locations identified in the extreme 
southern portion of the Sitka Sound, and potentially in the Project 
Area, including rocky outcroppings near Biorka Island, where seals have 
been observed in low numbers. Prey resources inside Symonds Bay are 
limited, particularly when compared to the northern coastal areas of 
Sitka Sound. While individual seals may occur in Symonds Bay, it is 
unlikely that seals would be attracted to Symonds Bay to forage. While 
their occurrence in the Action Area is possible, it is infrequent to 
uncommon and only small numbers of approximately five animals per day 
are expected to potentially be in the Project area during the 
construction window.

Harbor Porpoise

    In the Pacific, harbor porpoise are found in coastal and inland 
waters from Point Conception, California to Alaska and across to 
Kamchatka and Japan (Gaskin 1984). Harbor porpoise appear to have more 
restricted movements along the western coast of the continental U.S. 
than along the eastern coast. In the Gulf of Alaska and Southeast 
Alaska they are observed most frequently in waters less than 350 ft 
(107 m) deep (Dahlheim et al., 2009). There are three harbor porpoise 
stocks in Alaska: The Bering Sea Stock; the Southeast Alaska Stock; and 
the Gulf of Alaska Stock (Angliss and Allen 2015). Only the Southeast 
Alaska stock occurs in the Project area. The mean group size of harbor 
porpoise in Southeast Alaska

[[Page 41235]]

is estimated at two to three individuals (Dahlheim et al., 2009).
    This species can be found in Sitka Sound throughout the year but 
individuals are infrequently observed during the summer months by the 
whale watching industry. Harbor porpoise are infrequently observed in 
nearshore Sitka Sound areas in summer by hikers on the coastal trails 
that parallel the coastline near Sitka. At times throughout the year, 
they likely forage exclusively on herring and may be more abundant when 
herring are present. During surveys for seabirds, marine mammals and 
forage fish conducted in Sitka Sound during July 2000, relatively few 
marine mammals were observed during this period. However, one harbor 
porpoise was observed in coastal/shelf waters of northeast Sitka Sound 
(Piatt and Dragoo 2005).

Killer Whale

    Killer whales are found throughout the North Pacific. Along the 
west coast of North America, killer whales occur along the entire 
Alaskan coast, in British Columbia and Washington inland waterways, and 
along the outer coasts of Washington, Oregon, and California (Allen and 
Angliss 2014). Seasonal and year-round occurrence has been documented 
for killer whales throughout Alaska and in the intra-coastal waterways 
of British Columbia and Washington State.
    Killer whales that are observed in Southeast Alaska could belong to 
one of three different stocks: Eastern North Pacific Northern Resident 
Stock (Northern residents); Gulf of Alaska, Aleutian Islands, and 
Bering Sea Transient Stock (Gulf of Alaska transients); or West Coast 
Transient Stock. The Gulf of Alaska Transient Stock occupies a range 
that includes southeastern Alaska. Resident killer whales do not occur 
in Sitka Sound. However, transient killer whales from either the Gulf 
of Alaska transient group or West Coast Transient Stock have been 
observed in the sound. These whales are observed infrequently during 
summer months with five to six sightings noted throughout the summer by 
the whale-watching industry. Dahlheim et al. (2009) found that 
transient killer whale mean group size ranged from four to six 
individuals in Southeast Alaska. Generally, transient killer whales 
follow movements of, and prey on, Steller sea lions and harbor seals. 
Killer whales have been observed in the waters outside of Sitka Sound 
near the haulouts at Kaiuchali Island and outside of Kruzof Island when 
sea lions are present. This behavioral distribution is characteristic 
of killer whales and consistent with killer whale sightings around 
other Steller sea lion haul-out locations in southeast Alaska (Dahlheim 
et al., 2009). Given the low numbers of Steller sea lions in Sitka 
Sound during summer, it is consistent that transient killer whales 
would be considered infrequent to uncommon in the Project area during 
these months.

Humpback Whale

    Humpback whales were listed as endangered under the ESA in 1970. As 
a result of the ESA listing, the central North Pacific Stock of 
humpback whale was also designated as depleted under the MMPA. The 
humpback whale is also considered a strategic stock under the MMPA. 
NMFS proposed a revised species-wide listing of the humpback whale in 
2015 and a revision to the status of humpback whale DPSs was finalized 
by NMFS on September 8, 2016 (NMFS 2016b), effective October 11, 2016. 
In the final decision, NMFS recognized the existence of 14 DPSs, 
classified four of those as endangered and one as threatened, and 
determined that the remaining nine DPSs do not warrant protection under 
the ESA. Three DPSs of humpback whales occur in waters off the coast of 
Alaska: The endangered Western North Pacific (WNP) DPS, the threatened 
Mexico DPS, and the Hawaii DPS, which is not listed under the ESA. 
Humpback whales in Southeast Alaska are most likely to be from the 
Hawaii DPS (93.9 percent probability) (Wade et al., 2016).
    The humpback whales of Southeast Alaska and Northern British 
Columbia form a genetically discrete feeding aggregation and return to 
specific feeding locations in southeast Alaska including Sitka Sound. 
Humpback whale seasonal distribution varies from infrequent (very low 
in number during summer), to common (very abundant during late fall 
through spring). Humpback whales are most abundant in Sitka Sound from 
late fall through April when they forage on large densities of herring 
(Liddle et al., 2015a). The seasonal increase in whale abundance 
corresponds to increases in Pacific herring biomass during pre-
spawning, spawning and overwintering periods (Liddle et al., 2015b). 
Whales feed on large schools of adult, over-wintering herring 
throughout winter, and on pre-spawning and spawning aggregations of 
herring in spring. Sitka Sound is believed to be a last feeding stop 
for humpback whales as they migrate to winter breeding and calving 
waters in Hawaii. During winter months, groups of 30 to 40 humpback 
whales have been observed by the whale watching industry from the 
coastline of Sitka Sound. However, humpback whales stagger their 
departure from the feeding grounds, suggesting they also stagger their 
return. This could create the impression that whales had been present 
throughout the entire winter in the sound when it is unlikely that any 
individual whale remains in Sitka Sound throughout the entire winter 
(Heintz et al., 2010). The abundance of humpbacks in Sitka Sound 
changes by several orders of magnitude from one season to another in 
response to dense schools of herring in the sound (Liddle et al., 
2015b). They are generally present in large numbers from late fall-
early winter through mid- to late-spring, but are infrequent to 
uncommon during the mid-summer months when herring are absent. During 
mid-summer, tour boat operators generally observe four to five whales 
per day near rocky islets in the middle of Sitka Sound.

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

    This section includes a summary and discussion of the ways that 
components of the specified activity (e.g., sound produced by pile 
driving and removal) may impact marine mammals and their habitat. The 
Estimated Take by Incidental Harassment section later in this document 
will include a quantitative analysis of the number of individuals that 
are expected to be taken by this activity. The Negligible Impact 
Analysis section will consider 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 decibel (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

[[Page 41236]]

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 1 
microPascal ([mu]Pa). One pascal is the pressure resulting from a force 
of one 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 
DTH 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 (such as 
those used by the U.S. Navy). 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

[[Page 41237]]

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 severity of injury, and sound 
energy is distributed over a greater amount of time (Nedwell and 
Edwards 2002; Carlson et al., 2005).

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals, 
and exposure to sound can have deleterious effects. To appropriately 
assess these potential effects, 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 
measured or estimated hearing ranges on the basis of available 
behavioral data, audiograms derived using auditory evoked potential 
techniques, anatomical modeling, and other data. The lower and/or upper 
frequencies for some of these functional hearing groups have been 
modified from those designated by Southall et al. (2007). The marine 
mammal hearing groups and the associated frequencies are indicated 
below in Table 5 (note that these frequency ranges do not necessarily 
correspond to the range of best hearing, which varies by species).

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

    As mentioned previously in this document, five marine mammal 
species (three cetaceans and two pinnipeds) may occur in the Project 
area. Of these three cetaceans, one is classified as a low-frequency 
cetacean (i.e. humpback whale), one is classified as a mid-frequency 
cetacean (i.e., killer whale), and one is classified as a high-
frequency cetacean (i.e., harbor porpoise) (Southall et al., 2007). 
Additionally, harbor seals are classified as members of the phocid 
pinnipeds in water functional hearing group, while Steller sea lions 
are grouped under the Otariid pinnipeds in water functional hearing 
group. A species' functional hearing group is a consideration when we 
analyze the effects of exposure to sound on marine mammals.

Acoustic Impacts

    Please refer to the information given previously (Description of 
Sound Sources) regarding sound, characteristics of sound types, and 
metrics used in this document. 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 the FAA'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 the FAA'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

[[Page 41238]]

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) 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.
    Non-auditory physiological effects or injuries that theoretically 
might occur in marine mammals exposed to high level underwater sound or 
as a secondary effect of extreme behavioral reactions (e.g., change in 
dive profile as a result of an avoidance reaction) caused by exposure 
to sound include neurological effects, bubble formation, resonance 
effects, and other types of organ or tissue damage (Cox et al., 2006; 
Southall et al., 2007; Zimmer and Tyack 2007). The FAA'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.
    1. Temporary threshold shift--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 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).
    2. 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

[[Page 41239]]

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 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 as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
(Eschrictius robustus) are known to change direction--deflecting from 
customary migratory paths--in order to avoid noise from seismic surveys 
(Malme et al., 1984). Avoidance may be short-term, with animals 
returning to the area once the noise has ceased (e.g., Bowles et al., 
1994; Goold, 1996; Stone et al., 2000; Morton and Symonds, 2002; Gailey 
et al., 2007). Longer-term displacement is possible, however, which may 
lead to changes in abundance or distribution patterns of the affected 
species in the affected region if habituation to the presence of the 
sound does not occur (e.g., Blackwell et al., 2004; Bejder et al., 
2006; Teilmann et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus 1996). The result of a flight response could range from brief, 
temporary exertion and displacement from the area where the signal 
provokes flight to, in extreme cases, marine mammal strandings (Evans 
and England 2001). However, it should be noted that response to a 
perceived predator does not necessarily invoke flight (Ford and Reeves 
2008), and whether individuals are solitary or in groups may influence 
the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil 1997; Fritz et al., 2002; Purser and Radford 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour

[[Page 41240]]

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.
    3. Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle 1950; Moberg 
2000). In many cases, an animal's first and sometimes most economical 
(in terms of energetic costs) response is behavioral avoidance of the 
potential stressor. Autonomic nervous system responses to stress 
typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg 1987; Blecha 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker 2000; Romano 
et al., 2002b) and, more rarely, studied in wild populations (e.g., 
Romano et al., 2002a). For example, Rolland et al. (2012) found that 
noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC, 2003).
    4. 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.

[[Page 41241]]

Acoustic Effects, Underwater

    Potential Effects of DTH drilling and Pile Driving and Removal 
Sound--The effects of sounds from DTH drilling and pile driving and 
removal 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 and removal 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/removal 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 removal 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).
    Hearing Impairment and Other Physical Effects--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 6).
    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 (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 haul-outs 
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 expected to 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

[[Page 41242]]

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' as a result 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 
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 Sitka Sound (e.g., most of the 
impacted area is limited to inside Symonds Bay, and some scenarios 
include a ZOI that extends several km into Sitka Sound (see the FAA's 
application)). 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 
Sitka Sound.
    The duration of the construction activities is relatively short. 
The construction window is for a maximum of 70 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 by Incidental Harassment

    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

[[Page 41243]]

not limited to, migration, breathing, nursing, breeding, feeding, or 
sheltering (Level B harassment).
    Authorized takes would be by Level A and Level B harassment, in the 
form of disruption of behavioral patterns for individual marine mammals 
resulting from exposure to vibratory and impact pile driving and 
removal and DTH drilling, and potential PTS for animals that may 
transit through the Level A zones undetected. Based on the nature of 
the activity and the anticipated effectiveness of the mitigation 
measures (i.e., soft start, ramp-up, etc.--discussed in detail below in 
Proposed Mitigation section), Level A harassment is not anticipated; 
however, a small number of takes by Level A harassment are proposed to 
be authorized for all species as a precaution if animals go undetected 
before a shutdown is in place.
    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.
    The estimation of marine mammal takes typically uses the following 
calculation since site-specific density is unavailable:
    Level B exposure estimate = N (number of animals) in the area * 
Number of days of noise generating activities.

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) or intermittent 
(e.g., scientific sonar) sources.
    The FAA's proposed activities include the use of continuous 
(vibratory pile driving and DTH drilling) and impulsive (impact pile 
driving) sources, and therefore the 120 and 160 dB re 1 [mu]Pa (rms) 
are applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (NMFS 2016) identifies dual criteria to assess auditory 
injury (Level A harassment) to five different marine mammal groups 
(based on hearing sensitivity) as a result of exposure to noise from 
two different types of sources (impulsive or non-impulsive). The FAA's 
proposed activity includes the use of impulsive (impact pile driving) 
and non-impulsive (vibratory pile driving and DTH drilling) sources.
    These thresholds were developed by compiling and synthesizing the 
best available science and soliciting input multiple times from both 
the public and peer reviewers to inform the final product, and are 
provided in the table 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 6--Thresholds Identifying the Onset of Permanent Threshold Shift
------------------------------------------------------------------------
                                      PTS onset acoustic thresholds *
                                             (received level)
          Hearing group          ---------------------------------------
                                       Impulsive         Non-impulsive
------------------------------------------------------------------------
Low-frequency cetaceans.........  Cell 1, Lpk,flat:   Cell 2, LE,LF,24h:
                                   219 dB,LE,LF,24h:   199 dB.
                                   183 dB.
Mid-frequency cetaceans.........  Cell 3, Lpk,flat:   Cell 4, LE,MF,24h:
                                   230 dB,LE,MF,24h:   198 dB.
                                   185 dB.
High-frequency cetaceans........  Cell 5, Lpk,flat:   Cell 6, LE,HF,24h:
                                   202 dB,LE,HF,24h:   173 dB.
                                   155 dB.
Phocid Pinnipeds (underwaters)..  Cell 7, Lpk,flat:   Cell 8, LE,PW,24h:
                                   218 dB,LE,PW,24h:   201 dB.
                                   185 dB.
Otariid Pinnipeds (underwater)..  Cell 9, Lpk,flat:   Cell 10,
                                   232 dB,LE,OW,24h:   LE,OW,24h: 219
                                   203 dB.             dB.
------------------------------------------------------------------------
* NMFS 2016.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds.
    Pile driving and removal and DTH drilling generates underwater 
noise that can potentially result in disturbance to marine mammals in 
the Project area. Transmission loss (TL) is the decrease in acoustic 
intensity as an acoustic pressure wave propagates out from a source. TL 
parameters vary with frequency, temperature, sea conditions, current, 
source and receiver depth, water depth, water chemistry, and bottom 
composition and topography. The general formula for underwater TL is:

TL = B * log10(R1/R2),

where:

R1 = the distance of the modeled SPL from the driven 
pile, and
R2 = the distance from the driven pile of the initial 
measurement.

    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the

[[Page 41244]]

water bathymetry and presence or absence of reflective or absorptive 
conditions including in-water structures and sediments. Spherical 
spreading occurs in a perfectly unobstructed (free-field) environment 
not limited by depth or water surface, resulting in a 6 dB reduction in 
sound level for each doubling of distance from the source (20 * 
log[range]). Cylindrical spreading occurs in an environment in which 
sound propagation is bounded by the water surface and sea bottom, 
resulting in a reduction of 3 dB in sound level for each doubling of 
distance from the source (10 * log[range]). A practical spreading value 
of 15 is often used under conditions, such as at the Biorka Island 
dock, where water increases with depth as the receiver moves away from 
the shoreline, resulting in an expected propagation environment that 
would lie between spherical and cylindrical spreading loss conditions. 
Practical spreading loss (4.5 dB reduction in sound level for each 
doubling of distance) is assumed here.
    Underwater Sound--The intensity of pile driving and removal sounds 
is greatly influenced by factors such as the type of piles, hammers, 
and the physical environment in which the activity takes place. A 
number of studies, primarily on the west coast, have measured sound 
produced during underwater pile driving projects. These data are 
largely for impact driving of steel pipe piles and concrete piles as 
well as vibratory driving of steel pipe piles.
    JASCO Applied Sciences (JASCO) conducted acoustic modeling of pile 
installation and removal activities planned for the Project, which is 
included as Appendix A of the FAA's application. To assess potential 
underwater noise exposure of marine mammals during construction 
activities, Quijano and Austin (2017) determined source levels for six 
different construction scenarios (see Table 3). The source levels are 
frequency-dependent and suitable for modeling underwater acoustic 
propagation using JASCO's Marine Operations Noise Model (MONM). The 
modeling predicted the extent of ensonification and the acoustic 
footprint from construction activities, taking into account the effects 
of pile driving equipment, bathymetry, sound speed profile, and seabed 
geoacoustic parameters. Auditory weighting was applied to the modeled 
sound fields to estimate received levels relative to hearing 
sensitivities of five marine mammal hearing groups following NMFS 2016 
guidance.
    The results are based on currently adopted sound level thresholds 
for auditory injury (Level A) expressed as peak pressure level (PK) and 
24-hr sound exposure level (SEL), and behavioral disturbance (Level B) 
expressed as sound pressure level (SPL). Using these guidelines, 
Quijano and Austin (2017) calculated the maximum extent (distance and 
ensonified areas) of the Level A and Level B exposure zones for each 
marine mammal functional hearing group. This was calculated for both 
impact and vibratory pile driving of 18- and 30-in piles for each of 
the following six Project scenarios.
    The model required as input, source sound levels in \1/3\-octave 
bands between 10 Hz and 25 kHz. Source levels for sheet pile and H pile 
installation were obtained from literature, but the available 
measurements did not cover the full frequency spectrum of interest; 
data for vibratory installation of sheet and H piles were available to 
maximum frequencies of 4 kHz and 10 kHz, respectively. Modeling of the 
six construction scenarios at the Project site on Biorka Island 
followed three steps:
    1. Piles driven into the sediment by impact, vibratory, or downhole 
drilling were characterized as sound-radiating sources. Source levels 
in \1/3\-octave-bands were obtained by modeling or by adjusting source 
levels found in the literature. The exact method to obtain the \1/3\-
octave-band levels depends on the pile geometry and pile driving 
equipment, and it is described on a case-by-case basis (see Appendix 
A);
    2. Underwater sound propagation was applied to predict how sound 
propagates from the pile into the water column as a function of range, 
depth, and azimuthal direction. Propagation depends on several 
conditions including the frequency content of the sound, the 
bathymetry, the sound speed in the water column, and sediment 
geoacoustics; and
    3. The propagated sound field was used to compute received levels 
over a grid of simulated receivers, from which distances to criteria 
thresholds and maps of ensonified areas were generated.
    Modeled results are presented as tables of distances at which SPLs 
or SELs fell below thresholds defined by criteria. For marine mammal 
injury, the Level A thresholds considered here follow the NMFS 
guidelines (NMFS 2016). A detailed description of the modeling process 
is provided in Appendix A of the FAA's IHA application.

[[Page 41245]]

[GRAPHIC] [TIFF OMITTED] TN30AU17.000

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    At-sea densities for marine mammal species have not been determined 
for marine mammals in Sitka Sound; therefore, all estimates here are 
determined by using observational data from biologists, peer-reviewed 
literature, and information obtained from personal communication with 
researchers and state and Federal biologists, and from local charter 
boat operators.

Harbor Seals

    Harbor seals are expected to be in the Project area in low numbers 
(see Description of Marine Mammals in the Area of the Specified 
Activity Section). We estimate that up to five harbor seals per day may 
be present in the Project area on all days of construction. Therefore, 
we propose to authorize 350 takes by Level B harassment. Because the 
Level A ZOI for harbor seals is nearly 1 km, the FAA requests up to two 
harbor seal takes by Level A harassment if the animals enter the ZOI 
undetected and marine mammal observers (MMO)s are not able to request a 
shutdown prior to the seals being exposed to potential Level A 
harassment.

Steller Sea Lion

    Steller sea lion abundance in the Project area is dependent on prey 
availability. Prey species are uncommon during the Project window; 
therefore, sea lion abundance is expected to be low. The FAA estimates 
that five sea lions may be in the Project area every day (70 days) of 
construction, therefore, we estimate that 350 sea lions may be taken by 
Level B harassment. We estimate that these takes would be split equally 
between the eDPS and wDPS (175 each). The Level A zone is less than 10 
m; however, to be conservative, the FAA is requesting a small group of 
Steller sea lions to be taken by Level A harassment. This would equate 
to six total animals if split equally by DPS (3 each).

Humpback Whale

    Humpback whales are found in Sitka Bay seasonally. During mid-
summer, tour boats generally see four to five whales per day, in the 
middle of Sitka Sound. Therefore, a count of 5 humpback whales per day 
(70 days) was used to estimate takes per day on every day of 
construction for a total of 350 takes by Level B harassment. All takes 
would be from the Central North Pacific stock under the MMPA. For ESA 
purposes, 93.9 percent would be from the Hawaii DPS (328 animals) and 
6.1 percent would be from the Mexico stock (22 animals) based on Wade 
et al., 2016. The maximum distance at which a humpback whale may be 
exposed to noise levels that exceed Level A thresholds is 1.4 km during 
Scenario 6. Even though the ensonified area extends outside of the 
entrance to Symonds Bay, a MMO stationed near the mouth of the bay at 
Hanus Point would be able to see a humpback whale outside Symonds Bay 
before it enters the Level A zone and could shut down the noise 
producing activity to avoid Level A take. In the unlikely event a whale 
would go undetected and enter the Level A zone, the FAA has requested 
three takes by Level A harassment for humpback whales. We estimate that 
all three humpback whales would be from the Hawaii DPS.

[[Page 41246]]

Killer Whale

    Generally, transient killer whales follow the movements of Steller 
sea lions and harbor seals on which they prey. Given the low numbers of 
Steller sea lions in Sitka Sound during summer, it is consistent that 
transient killer whales would also be rare or infrequent in the Project 
area (e.g., killer whales were only observed on five or six days by the 
whale watching industry). Small groups of 5 to 6 transient killer 
whales per day could be observed throughout the summer months; 
therefore, we estimate that a group of 6 animals could enter the 
Project area on 6 occasions during the construction window, for a total 
of 36 takes by Level B harassment. No Level A takes of killer whales is 
proposed to be authorized for this species. The maximum linear distance 
to the Level A threshold for killer whales is less than 250 m from the 
source and a MMO would be able to observe animals at this distance and 
shutdown activities in time to avoid Level A take.

Harbor Porpoise

    Harbor porpoise are expected to occur in the Project area in low 
numbers during the construction window. Sightings during this time 
period are infrequent; this species is not observed every day. The mean 
group size of harbor porpoise in Southeast Alaska was estimated to be 
between 2 to 3 individuals (Dahlheim et al., 2009); therefore, we 
conservatively estimate that a group of three harbor porpoise may be 
present every other day of construction for a total of 105 takes by 
Level B harassment. The distances to Level A thresholds for harbor 
porpoise (HFC) are largest during impulse driving under Scenarios 5 and 
6 (see Table 3), and extend beyond the entrance to Symonds Bay. The 
duration of Scenarios 5 and 6 is expected to be 21 days (see Table 3); 
therefore, we expect that a small group of three harbor porpoise may 
enter the Level A zone on half of the days of Scenarios 5 and 6 (10.5 
days) for a total of 32 takes by Level A harassment.

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate.
    All estimates are conservative and include the following 
assumptions:
     All pilings installed at each site would have an 
underwater noise disturbance equal to the piling that causes the 
greatest noise disturbance (i.e., the piling farthest from shore) 
installed with the method that has the ZOI. The largest underwater 
disturbance (Level B) ZOI would be produced by DTH drilling; therefore 
take estimates were calculated using the vibratory pile-driving ZOIs. 
The ZOIs for each threshold are not spherical and are truncated by land 
masses on either side of the Project area, which would dissipate sound 
pressure waves.
     Exposures were based on an estimated total of 70 work 
days. Each activity ranges in amount of days needed to be completed 
(Table 3).
     All marine mammal individuals potentially available are 
assumed to be present within the relevant area, and thus incidentally 
taken;
     An individual can only be taken once during a 24-hour 
period; and,
     Exposures to sound levels at or above the relevant 
thresholds equate to take, as defined by the MMPA.
    Estimates of potential instances of take may be overestimates of 
the number of individuals taken. In the context of stationary 
activities such as pile driving and in areas where resident animals may 
be present, this number represents the number of total take that may 
accrue to a smaller number of individuals, with some number of animals 
being exposed more than once per individual. While pile driving and 
removal can occur any day throughout the in-water work window, and the 
analysis is conducted on a per day basis, only a fraction of that time 
(typically a matter of hours on any given day) is actually spent pile 
driving/removal. The potential effectiveness of mitigation measures in 
reducing the number of takes is typically not quantified in the take 
estimation process. For these reasons, these take estimates may be 
conservative.

          Table 8--Calculations for Incidental Take Estimation
------------------------------------------------------------------------
                                    Takes proposed to  Takes proposed to
                                     be authorized by   be authorized by
              Species                    Level A            Level B
                                        harassment         harassment
------------------------------------------------------------------------
Steller sea lion: Eastern and                       6                350
 Western stock....................
Harbor seal.......................                  2                350
Humpback whale....................                  3                350
Killer whale: Eastern North                         0                 36
 pacific Gulf of Alaska, Aleutian
 Island, and Bering Sea Transient
 stock and West Coast Transient
 stock............................
Harbor porpoise...................                 32                105
------------------------------------------------------------------------

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 balance 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--
which considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range), as well as the likelihood that 
the measure will be effective if implemented; and the likelihood of 
effective implementation, and;
    (2) The practicability of the measures for applicant 
implementation, which

[[Page 41247]]

may consider such things as cost, impact on operations, and, in the 
case of a military readiness activity, personnel safety, practicality 
of implementation, and impact on the effectiveness of the military 
readiness activity.
    The ZOIs were used to develop mitigation measures for pile driving 
and removal activities at the Project area. The ZOIs effectively 
represent the mitigation zone that would be established around each 
pile to prevent Level A harassment to marine mammals, while providing 
estimates of the areas within which Level B harassment might occur. In 
addition to the specific measures described later in this section, the 
FAA would conduct briefings between construction supervisors and crews, 
marine mammal monitoring team, and staff prior to the start of all pile 
driving activity, and when new personnel join the work, in order to 
explain responsibilities, communication procedures, marine mammal 
monitoring protocol, and operational procedures.

Monitoring and Shutdown for Construction Activities

    The following measures would apply to the FAA's mitigation through 
shutdown and disturbance zones:
    Shutdown Zone--For all pile driving activities, the FAA will 
establish a shutdown zone intended to contain the area in which SPLs 
equal or exceed the auditory injury criteria for cetaceans and 
pinnipeds. The purpose of a shutdown zone is 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), thus 
preventing injury of marine mammals (as described previously under 
Potential Effects of the Specified Activity on Marine Mammals, serious 
injury or death are unlikely outcomes even in the absence of mitigation 
measures). Modeled radial distances for shutdown zones are shown in 
Table 9. However, a minimum shutdown zone of 10 m will be established 
during all pile driving activities, regardless of the estimated zone; 
and
    Disturbance Zone--Disturbance zones are the areas in which SPLs 
equal or exceed 160 and 120 dB rms (for impulse and continuous sound, 
respectively). Disturbance zones provide utility for monitoring 
conducted for mitigation purposes (i.e., shutdown zone monitoring) by 
establishing monitoring protocols for areas adjacent to the shutdown 
zones. Monitoring of disturbance zones enables observers to be aware of 
and communicate the presence of marine mammals in the Project area but 
outside the shutdown zone and thus prepare for potential shutdowns of 
activity. However, the primary purpose of disturbance zone monitoring 
is for documenting instances of Level B harassment; disturbance zone 
monitoring is discussed in greater detail later (see Proposed 
Monitoring and Reporting). Nominal radial distances for disturbance 
zones are shown in Table 9.
    Given the size of the disturbance zone for vibratory pile driving 
and DTH drilling, it is impossible to guarantee that all animals would 
be observed or to make comprehensive observations of fine-scale 
behavioral reactions to sound, and only a portion of the zone (e.g., 
what may be reasonably observed by visual observers stationed between 
Symonds Bay and Sitka Sound) would be observed. In order to document 
observed instances of harassment, monitors record all marine mammal 
observations, regardless of location. The observer's location, as well 
as the location of the pile being driven, is known from a GPS. The 
location of the animal is estimated as a distance from the observer, 
which is then compared to the location from the pile. It may then be 
estimated whether the animal was exposed to sound levels constituting 
incidental harassment on the basis of predicted distances to relevant 
thresholds in post-processing of observational and acoustic data, and a 
precise accounting of observed incidences of harassment created. This 
information may then be used to extrapolate observed takes to reach an 
approximate understanding of actual total takes.
BILLING CODE 3510-22-P

[[Page 41248]]

[GRAPHIC] [TIFF OMITTED] TN30AU17.001

BILLING CODE 3510-22-C
    Monitoring Protocols--Monitoring would be conducted before, during, 
and after pile driving and vibratory removal activities. In addition, 
observers shall record all instances of marine mammal occurrence, 
regardless of distance from activity, and shall document any behavioral 
reactions in concert with distance from piles being driven. 
Observations made outside the shutdown zone will not result in 
shutdown; that pile segment would be completed without cessation, 
unless the animal approaches or enters the shutdown zone, at which 
point all pile driving activities would be halted. Monitoring will take 
place from 15 minutes prior to initiation through 30 minutes post-
completion of pile driving and removal activities. 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 30 minutes. Please see Section 11 of 
the FAA's application (www.nmfs.noaa.gov/pr/permits/incidental/construction.htm), for the FAA's proposed monitoring protocols.
    The following additional measures apply to visual monitoring:
    (1) 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. A minimum of two 
observers will be required for all pile driving/removal activities. 
Marine Mammal Observer (MMO) requirements for construction actions are 
as follows:
    (a) Independent observers (i.e., not construction personnel) are 
required;
    (b) At least one observer must have prior experience working as an 
observer;
    (c) Other observers (that do not have prior experience) may 
substitute education (undergraduate degree in biological science or 
related field) or training for experience;
    (d) Where a team of three or more observers are required, one 
observer should be designated as lead observer or monitoring 
coordinator. The lead observer must have prior experience working as an 
observer; and
    (e) NMFS will require submission and approval of observer resumes.
    (2) Qualified MMOs are trained biologists, and need the following 
additional minimum qualifications:
    (a) 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;
    (b) Ability to conduct field observations and collect data 
according to assigned protocols;

[[Page 41249]]

    (c) Experience or training in the field identification of marine 
mammals, including the identification of behaviors;
    (d) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    (e) 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; and
    (f) 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.
    (3) Prior to the start of pile driving activity, the shutdown zone 
will be monitored for 15 minutes to ensure that it is clear of marine 
mammals. Pile driving will only commence once observers have declared 
the shutdown zone clear of marine mammals; animals will be allowed to 
remain in the shutdown zone (i.e., must leave of their own volition) 
and their behavior will be monitored and documented. The shutdown zone 
may only be declared clear, and pile driving started, when the entire 
shutdown zone is visible (i.e., when not obscured by dark, rain, fog, 
etc.). In addition, if such conditions should arise during impact pile 
driving that is already underway, the activity would be halted.
    (4) If a marine mammal approaches or enters the shutdown zone 
during the course of pile driving operations, activity will be halted 
and delayed until either the animal has voluntarily left and been 
visually confirmed beyond the shutdown zone or 15 minutes have passed 
without re-detection of small cetaceans and pinnipeds, and 30 minutes 
for humpback whales. Monitoring will be conducted throughout the time 
required to drive a pile.
    (5) Using delay and shut-down procedures, if a species for which 
authorization has not been granted or if a species for which 
authorization has been granted but the authorized takes are met, 
approaches or is observed within the Level B harassment zone, 
activities will shut down immediately and not restart until the animals 
have been confirmed to have left the area.

Soft Start

    The use of a soft start procedure is believed to provide additional 
protection to marine mammals by warning or providing a chance to leave 
the area prior to the hammer operating at full capacity, and typically 
involves a requirement to initiate sound from the hammer at reduced 
energy followed by a waiting period. This procedure is repeated two 
additional times. It is difficult to specify the reduction in energy 
for any given hammer because of variation across drivers and, for 
impact hammers, the actual number of strikes at reduced energy will 
vary because operating the hammer at less than full power results in 
``bouncing'' of the hammer as it strikes the pile, resulting in 
multiple ``strikes.'' For impact driving, we require an initial set of 
three strikes from the impact hammer at reduced energy, followed by a 
30-second waiting period, then 2 subsequent 3 strike sets. Soft start 
will be required at the beginning of each day's impact pile driving 
work and at any time following a cessation of impact pile driving of 30 
minutes or longer.

Timing Restrictions

    The FAA will only conduct construction activities during daytime 
hours. Construction will also be restricted to the months of May 
through September to avoid overlap with times when marine mammals have 
higher densities in the Project area.
    We have carefully evaluated the FAA's proposed mitigation measures 
and considered their effectiveness in past implementation to 
preliminarily determine whether they are likely to effect the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat.
    Any mitigation measure(s) we prescribe should be able to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to the accomplishment of one or more of 
the general goals listed below:
    (1) Avoidance or minimization of injury or death of marine mammals 
wherever possible (goals 2, 3, and 4 may contribute to this goal);
    (2) A reduction in the number (total number or number at 
biologically important time or location) of individual marine mammals 
exposed to stimuli expected to result in incidental take (this goal may 
contribute to 1, above, or to reducing takes by behavioral harassment 
only);
    (3) A reduction in the number (total number or number at 
biologically important time or location) of times any individual marine 
mammal would be exposed to stimuli expected to result in incidental 
take (this goal may contribute to 1, above, or to reducing takes by 
behavioral harassment only);
    (4) A reduction in the intensity of exposure to stimuli expected to 
result in incidental take (this goal may contribute to 1, above, or to 
reducing the severity of behavioral harassment only);
    (5) Avoidance or minimization of adverse effects to marine mammal 
habitat, paying particular attention to the prey base, blockage or 
limitation of passage to or from biologically important areas, 
permanent destruction of habitat, or temporary disturbance of habitat 
during a biologically important time; and
    (6) For monitoring directly related to mitigation, an increase in 
the probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation.
    Based on our evaluation of the FAA's proposed measures, as well as 
any other potential measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on marine mammal species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth requirements pertaining to the 
monitoring and reporting of such taking. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. Effective reporting is critical to both 
compliance and 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 in action area (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

[[Page 41250]]

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) 
population, species, or stock;
     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 Marine Mammal Observations

    The FAA will collect sighting data and behavioral responses to 
construction for marine mammal species observed in the region of 
activity during the period of activity. All MMOs will be trained in 
marine mammal identification and behaviors and are required to have no 
other construction-related tasks while conducting monitoring. A minimum 
of two MMOs will be required for all pile driving/removal activities. 
The FAA will monitor the shutdown zone and disturbance zone before, 
during, and after pile driving, with observers located at the best 
practicable vantage points. Based on our requirements, the FAA would 
implement the following procedures for pile driving and removal:
     MMOs would be located at the best vantage point(s) in 
order to properly see the entire shutdown zone and as much of the 
disturbance zone as possible;
     During all observation periods, observers will use 
binoculars and the naked eye to search continuously for marine mammals;
     If the shutdown zones are obscured by fog or poor lighting 
conditions, pile driving at that location will not be initiated until 
that zone is visible. Should such conditions arise while impact driving 
is underway, the activity would be halted; and
     The shutdown and disturbance zones around the pile will be 
monitored for the presence of marine mammals before, during, and after 
any pile driving or removal activity.

Data Collection

    We require that observers use approved data forms. Among other 
pieces of information, the FAA will record detailed information about 
any 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. In addition, the FAA will attempt to 
distinguish between the number of individual animals taken and the 
number of incidences of take. We require that, at a minimum, the 
following information be collected on the sighting forms:
     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 if possible, 
the correlation to SPLs;
     Distance from pile driving or removal activities to marine 
mammals and distance from the marine mammals to the observation point;
     Description of implementation of mitigation measures 
(e.g., shutdown or delay);
     Locations of all marine mammal observations; and
     Other human activity in the area.

Reporting

    A draft report would be submitted to NMFS within 90 days of the 
completion of marine mammal monitoring, or 60 days prior to the 
requested date of issuance of any future IHA for projects at the same 
location, whichever comes first. The report will include marine mammal 
observations pre-activity, during-activity, and post-activity during 
pile driving and removal days, and will also provide descriptions of 
any behavioral responses to construction activities by marine mammals 
and a complete description of all mitigation shutdowns and the results 
of those actions and an extrapolated total take estimate based on the 
number of marine mammals observed during the course of construction. A 
final report must be submitted within 30 days following resolution of 
comments on the draft report.

Negligible Impact Analysis and Determinations

    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).
    Pile driving and removal activities associated with the dock 
replacement Project, as outlined previously, have the potential to 
disturb or displace marine mammals. Specifically, the specified 
activities may result in take, in the form of Level A and Level B 
harassment (PTS and behavioral disturbance), from underwater sounds 
generated from pile driving and removal. Potential takes could occur if 
individuals of these species are present in the ensonified zone when 
pile driving and removal occurs. Most of the Level A takes are 
precautionary as marine mammals are not expected to enter and stay in 
the Level A ensonified area for the duration needed to incur PTS. 
However, if all authorized takes be Level A harassment were to occur, 
they would be of small numbers compared to the stock sizes and would 
not adversely affect the stock through effects on annual rates of 
recruitment or survival. Additionally, the FAA's mitigation measures, 
including a shutdown of construction

[[Page 41251]]

activities if animals enter the Level A zone, further reduces the 
chance for PTS in marine mammals. Therefore, the effects to marine 
mammals are expected to be negligible.
    No TTS, serious injury, or mortality is anticipated given the 
nature of the activities and measures designed to minimize the 
possibility of injury to marine mammals. The potential for these 
outcomes is minimized through the construction method and the 
implementation of the planned mitigation measures. Specifically, 
vibratory and impact hammers and drilling will be the primary methods 
of installation. Impact pile driving produces short, sharp pulses with 
higher peak levels and much sharper rise time to reach those peaks. If 
impact driving is necessary, implementation of soft start and shutdown 
zones significantly reduces any possibility of injury. Given sufficient 
``notice'' through use of soft start (for impact driving), marine 
mammals are expected to move away from a sound source that is annoying 
prior to it becoming potentially injurious, however, as noted 
previously a small number of potential takes by PTS are proposed for 
authorization and have been analyzed. The FAA will use a minimum of two 
MMOs stationed strategically to increase detectability of marine 
mammals, enabling a high rate of success in implementation of shutdowns 
to avoid injury.
    The FAA's proposed activities are localized and of relatively short 
duration (a maximum of 70 days for pile driving and removal). The 
entire Project area is limited to Symonds Bay and into Sitka Sound for 
some scenarios. These localized and short-term noise exposures may 
cause short-term behavioral modifications in harbor seals, Steller sea 
lions, harbor porpoises, killer whales, and humpback whales. Moreover, 
the proposed mitigation and monitoring measures are expected to reduce 
the likelihood of injury. Additionally, no important feeding and/or 
reproductive areas for marine mammals are known to be within the 
ensonified area during the construction window.
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from other 
similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring) (e.g., Thorson and Reyff 
2006; Lerma 2014). Significant behavioral modifications that could 
potentially lead to effects on growth, survival, or reproduction are 
not expected to occur given the short duration and small scale of the 
project activities. Most likely, individuals will simply move away from 
the sound source and be temporarily displaced from the areas of pile 
driving and drilling, although even this reaction has been observed 
primarily only in association with impact pile driving. Thus, even 
repeated Level B harassment of some small subset of the overall stock 
is unlikely to result in any significant realized decrease in fitness 
for the affected individuals, and thus would not result in any adverse 
impact to the stock as a whole. Non-auditory physiological effects and 
masking are not expected to occur from the FAA's Project activities.
    The Project also is not expected to have significant adverse 
effects on affected marine mammals' habitat. The Project activities 
would not modify existing marine mammal habitat for a significant 
amount of time. The activities may cause some fish to leave the area of 
disturbance, thus temporarily impacting marine mammals' foraging 
opportunities in a limited portion of the foraging range. However, 
because of the short duration of the activities and the relatively 
small area of the habitat that may be affected, and the decreased 
potential of prey species to be in the Project area during the 
construction work window, the impacts to marine mammal habitat are not 
expected to cause significant or long-term negative consequences.
    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 or serious injury is anticipated or 
authorized;
     Level B harassment may consist of, at worst, temporary 
modifications in behavior (e.g. temporary avoidance of habitat or 
changes in behavior);
     The lack of important feeding, pupping, or other areas in 
the action area during the construction window;
     Mitigation is expected to minimize the likelihood and 
severity of the level of harassment; and
     The small percentage of the stock that may be affected by 
Project activities (<15 percent for all stocks).
    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 FAA's construction activities will have a 
negligible impact on the 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.
    Table 10 details the number of instances that animals could be 
exposed to received noise levels that could cause Level A and Level B 
harassment for the proposed work at the Project site relative to the 
total stock abundance. 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 instance of take occurred 
to a new individual--an extremely unlikely scenario. The total percent 
of the population (if each instance was a separate individual) for 
which take is requested is less than 15 percent for all stocks (Table 
10). For pinnipeds, especially harbor seals occurring in the vicinity 
of the Project area, there will almost certainly be some overlap in 
individuals present day-to-day, and the number of individuals taken is 
expected to be notably lower.
    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.

[[Page 41252]]



    Table 10--Estimated Numbers and Percentage of Stock That May Be Exposed to Level A and Level B Harassment
----------------------------------------------------------------------------------------------------------------
                                                     Proposed        Proposed        Stock(s)      Percentage of
                     Species                        authorized      authorized       abundance      total stock
                                                  Level A  takes  Level B  takes   estimate \1\      (percent)
----------------------------------------------------------------------------------------------------------------
Harbor Seal (Phoca vitulina)....................               2             350          14,855            2.37
Sitka/Chatham stock.............................
Steller sea lion (Eumatopias jubatus):
    Western U.S. Stock..........................               6             350          50,983           0.698
    Eastern U.S. Stock..........................  ..............  ..............          41,638           0.855
Killer whale (Orcinus orca):
    Eastern North Pacific, Gulf of AK, Aleutian                0              36             587            6.13
     Island, and Bering Sea Transient Stock.....
    West Coast Transient Stock..................  ..............  ..............             243            14.8
Humpback whale (Megaptera noviaengliae).........               3             350          10,103            3.49
Central North Pacific Stock.....................
Harbor Porpoise (Phocoena phocoena).............              32             105          11,146            1.23
Southeast Alaska Stock..........................
----------------------------------------------------------------------------------------------------------------
\1\ All stock abundance estimates presented here are from the 2016 Alaska Stock Assessment Report.

Unmitigable Adverse Impact Analysis and Determination

    In order to issue an IHA, NMFS must find that the specified 
activity will not have an ``unmitigable adverse impact'' on the 
subsistence uses of the affected marine mammal species or stocks by 
Alaskan Natives. NMFS has defined ``unmitigable adverse impact'' in 50 
CFR 216.103 as: an impact resulting from the specified activity: (1) 
That is likely to reduce the availability of the species to a level 
insufficient for a harvest to meet subsistence needs by: (i) Causing 
the marine mammals to abandon or avoid hunting areas; (ii) Directly 
displacing subsistence users; or (iii) Placing physical barriers 
between the marine mammals and the subsistence hunters; and (2) That 
cannot be sufficiently mitigated by other measures to increase the 
availability of marine mammals to allow subsistence needs to be met.
    Harbor seals and Steller sea lions are subsistence harvested in 
Alaska. During 2012, the estimated subsistence take of harbor seals in 
southeast Alaska was 595 seals with 49 of these taken near Sitka (Wolfe 
et al., 2013). This is the lowest number of seals taken since 1992 
(Wolfe et al., 2013) and is attributed to the decline in subsistence 
hunting pressure over the years as well as a decrease in efficiency per 
hunter (Wolf et al., 2013).
    The peak hunting season in southeast Alaska occurs during the month 
of November and again over the March to April time frame (Wolfe et al., 
2013). This corresponds to times when seals are aggregated in shoal 
areas as they prey on forage species such as herring, making them 
easier to find and hunt.
    The proposed Project is in an area where subsistence hunting for 
harbor seals or sea lions could occur (Wolfe et al., 2013), but the 
location is not preferred for hunting. There is little to no hunting 
documented in the vicinity and there are no harvest quotas for non-
listed marine mammals. For these reasons and the fact that Project 
activities would occur outside of the primary subsistence hunting 
seasons, there would be no impact on subsistence activities or on the 
availability of marine mammals for subsistence use.
    To satisfy requirements under Section 106 of the National Historic 
Preservation Act, R&M Consultants, Inc. reached out to the Sitka Tribe 
of Alaska, Central Council of the Tlingit and Haida, and Sealaska 
regarding cultural resources in 2016. No issues or concerns with the 
Project were raised during this effort.
    Based on the description of the specified activity, the measures 
described to minimize adverse effects on the availability of marine 
mammals for subsistence purposes, and the proposed mitigation and 
monitoring measures, NMFS has preliminarily determined that there will 
not be an unmitigable adverse impact on subsistence uses from the FAA's 
proposed activities.

Endangered Species Act

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

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to the FAA for conducting their Biorka Island Dock 
Replacement Project, 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 IHA is valid for 1 year from May 1, 2018 through April 30, 
2019.
    2. This IHA is valid only for pile driving and removal activities 
associated with the Biorka Island Dock Replacement Project in Symonds 
Bay, Alaska from May 1 to September 30, 2018.
    3. General Conditions
    (a) A copy of this IHA must be in the possession of the FAA, its 
designees, and work crew personnel operating under the authority of 
this IHA.
    (b) The species authorized for taking are summarized in Table 11.
    (c) The taking, by Level A and Level B harassment, is limited to 
the species

[[Page 41253]]

listed in condition 3(b). See Table 1 for numbers of take authorized.

                    Table 11--Authorized Take Numbers
------------------------------------------------------------------------
                                                        Authorized take
                       Species                       -------------------
                                                       Level A   Level B
------------------------------------------------------------------------
Harbor seal.........................................         2       350
California sea lion.................................         6       350
Harbor porpoise.....................................        32       105
Killer whale........................................         0        36
Humpback whale......................................         3       350
------------------------------------------------------------------------

    (d) The taking by injury (Level A harassment), serious injury, or 
death 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, 
unless authorization of take by Level A harassment is listed in 
condition 3(b) of this Authorization.
    (e) The FAA shall conduct briefings between construction 
supervisors and crews, marine mammal monitoring team, and staff prior 
to the start of all pile driving and removal activities, and when new 
personnel join the work.
    4. Mitigation Measures
    The holder of this Authorization is required to implement the 
following mitigation measures.
    (a) For all pile driving and removal, the FAA shall implement a 
minimum shutdown zone of 10 m radius around the pile. Additionally, the 
FAA shall implement shutdown zones for each construction scenario as 
presented in Table 12. If a marine mammal comes within or approaches 
the applicable shutdown zone, such operations shall cease.
[GRAPHIC] [TIFF OMITTED] TN30AU17.002

    (b) For in-water heavy machinery work other than pile driving 
(e.g., standard barges, tug boats, barge-mounted excavators, or 
clamshell equipment used to place or remove material), if a marine 
mammal comes within 10 meters, operations shall cease and vessels shall 
reduce speed to the minimum level required to maintain steerage and 
safe working conditions.
    (c) The FAA shall establish monitoring locations as described 
below. Please also refer to the FAA's application (see 
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm).
    i. For all pile driving and removal activities, a minimum of two 
observers shall be deployed, with one positioned to achieve optimal 
monitoring of the shutdown zones and the second positioned to achieve 
optimal monitoring of surrounding waters of Biorka dock and portions of 
Symonds Bay and Sitka Sound. If practicable, the second observer should 
be deployed to an elevated position with clear sight lines to the 
Project area.
    ii. These observers shall record all observations of marine 
mammals, regardless of distance from the pile being driven, as well as 
behavior and potential behavioral reactions of the animals.
    iii. All observers shall be equipped for communication of marine 
mammal observations amongst themselves and to other relevant personnel 
(e.g., those necessary to effect activity delay or shutdown).
    (d) Monitoring shall take place from 15 minutes prior to initiation 
of pile driving and removal activity through 30 minutes post-completion 
of pile driving and removal activity. In the event of a delay or 
shutdown of activity resulting

[[Page 41254]]

from marine mammals in the shutdown zone, animals shall be allowed to 
remain in the shutdown zone (i.e., must leave of their own volition) 
and their behavior shall be monitored and documented. Monitoring shall 
occur throughout the time required to drive a pile. The shutdown zone 
must be determined to be clear during periods of good visibility (i.e., 
the entire shutdown zone and surrounding waters must be visible to the 
naked eye).
    (e) If a marine mammal approaches or enters the shutdown zone, all 
pile driving and removal activities at that location shall be halted. 
If pile driving is halted or delayed due to the presence of a marine 
mammal, the activity may not commence or resume until either the animal 
has voluntarily left and been visually confirmed beyond the shutdown 
zone or fifteen minutes have passed without re-detection of small 
cetaceans and pinnipeds and 30 minutes for humpback whales.
    (f) Using delay and shut-down procedures, if a species for which 
authorization has not been granted or if a species for which 
authorization has been granted but the authorized takes are met, 
approaches or is observed within the Level B harassment zone (Table 2), 
activities will shut down immediately and not restart until the animals 
have been confirmed to have left the area.
    (g) Monitoring shall be conducted by qualified observers. Trained 
observers shall be placed from the best vantage point(s) practicable to 
monitor for marine mammals and implement shutdown or delay procedures 
when applicable through communication with the equipment operator. 
Observer training must be provided prior to project start and in 
accordance with the monitoring measures in the application, and shall 
include instruction on species identification (sufficient to 
distinguish the species listed in 3(b)), description and categorization 
of observed behaviors and interpretation of behaviors that may be 
construed as being reactions to the specified activity, proper 
completion of data forms, and other basic components of biological 
monitoring, including tracking of observed animals or groups of animals 
such that repeat sound exposures may be attributed to individuals (to 
the extent possible).
    (h) The FAA shall use soft start techniques recommended by NMFS for 
impact pile driving. Soft start requires contractors to provide an 
initial set of strikes at reduced energy, followed by a thirty-second 
waiting period, then two subsequent reduced energy strike sets. Soft 
start shall be implemented at the start of each day's impact pile 
driving and at any time following cessation of impact pile driving for 
a period of thirty minutes or longer.
    (i) Pile driving shall only be conducted during daylight hours.
    5. Monitoring
    The holder of this Authorization is required to conduct marine 
mammal monitoring during pile driving and removal activities. Marine 
mammal monitoring and reporting shall be conducted in accordance with 
the monitoring measures in the application.
    (a) The FAA shall collect sighting data and behavioral responses to 
pile driving and removal and drilling activities for marine mammal 
species observed in the region of activity during the period of 
activity. All observers shall be trained in marine mammal 
identification and behaviors, and shall have no other construction-
related tasks while conducting monitoring.
    (b) For all marine mammal monitoring, the information shall be 
recorded as described in the monitoring measures section of the 
application.
    6. Reporting
    The holder of this Authorization is required to:
    (a) Submit a draft report on all monitoring conducted under the IHA 
within 90 days of the completion of marine mammal monitoring, or 60 
days prior to the issuance of any subsequent IHA for projects at the 
Project area, whichever comes first. 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 informational 
elements described in the application, at minimum (see 
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm), and shall 
also include:
    i. Detailed information about any 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.
    ii. Description of attempts to distinguish between the number of 
individual animals taken and the number of incidents of take, such as 
ability to track groups or individuals.
    iii. An estimated total take estimate extrapolated from the number 
of marine mammals observed during the course of construction 
activities, if necessary.
    (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 a serious injury or mortality, the FAA shall immediately cease 
the specified activities and report the incident to the Office of 
Protected Resources, NMFS, and the Alaska Regional Stranding 
Coordinator. The report must include the following information:
    A. Time and date of the incident;
    B. Description of the incident;
    C. Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    D. Description of all marine mammal observations in the 24 hours 
preceding the incident;
    E. Species identification or description of the animal(s) involved;
    F. Fate of the animal(s); and
    G. 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 will work with the FAA to 
determine what measures are necessary to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. The FAA may not 
resume their activities until notified by NMFS.
    ii. In the event that the FAA 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), the FAA shall immediately 
report the incident to the Office of Protected Resources, NMFS, and the 
Alaska Regional Stranding Coordinator.
    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 will work with the FAA to determine 
whether additional mitigation measures or modifications to the 
activities are appropriate.
    iii. In the event that the FAA 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, scavenger damage), the FAA shall report the incident to 
the Office of Protected Resources, NMFS, and the Alaska Regional 
Stranding Coordinator, NMFS, within 24 hours of the discovery. The FAA 
shall provide photographs or 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

[[Page 41255]]

is having more than a negligible impact on the species or stock of 
affected marine mammals.

Request for Public Comments

    We request comment on our analyses, the draft authorization, and 
any other aspect of this Notice of Proposed IHAs for the FAA's dock 
replacement construction activities. Please include with your comments 
any supporting data or literature citations to help inform our final 
decision on the FAA's request for MMPA authorization.

    Dated: August 24, 2017.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2017-18347 Filed 8-29-17; 8:45 am]
 BILLING CODE 3510-22-P