Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to the Skagway Gateway Initiative Project, 26629-26658 [2016-10266]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 81, Number 85 (Tuesday, May 3, 2016)]
[Notices]
[Pages 26629-26658]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-10266]



[[Page 26629]]

Vol. 81

Tuesday,

No. 85

May 3, 2016

Part II





 Department of Commerce





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National Oceanic and Atmospheric Administration





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 Takes of Marine Mammals Incidental to Specified Activities; Taking 
Marine Mammals Incidental to the Skagway Gateway Initiative Project; 
Notice

Federal Register / Vol. 81 , No. 85 / Tuesday, May 3, 2016 / 
Notices

[[Page 26630]]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XE440


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Skagway Gateway Initiative 
Project

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

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

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SUMMARY: NMFS has received a request from the Municipality of Skagway 
(MOS) for authorization to take marine mammals incidental to 
reconstructing the existing ore dock in Skagway Harbor, Alaska, 
referred to as the Skagway Gateway Initiative project. The MOS requests 
that the IHA be valid for 1 year, from July 1, 2016 through June 30, 
2017. 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 MOS to incidentally take, marine 
mammals for its reconstruction of the Skagway ore terminal in Skagway, 
AK.

DATES: Comments and information must be received no later than June 2, 
2016.

ADDRESSES: Comments on the application 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 to the Internet at https://www.nmfs.noaa.gov/pr/permits/incidental/construction.htm without 
change. All personal identifying information (e.g., name, address) 
voluntarily submitted by the commenter may be publicly accessible. Do 
not submit confidential business information or otherwise sensitive or 
protected information.

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

SUPPLEMENTARY INFORMATION: 

Availability

    An electronic copy of the MOS's application and supporting 
documents, as well as a list of the references cited in this document, 
may be obtained by visiting the Internet at: https://www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing 
these documents, please call the contact listed above.

National Environmental Policy Act (NEPA)

    We are preparing an Environmental Assessment (EA) in accordance 
with NEPA and the regulations published by the Council on Environmental 
Quality and will consider comments submitted in response to this notice 
as part of that process. The EA will be posted at the foregoing Web 
site once it is finalized.

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request by U.S. 
citizens who engage in a specified activity (other than commercial 
fishing) within a specified area, the incidental, but not intentional, 
taking of small numbers of marine mammals, providing that certain 
findings are made and the necessary prescriptions are established.
    The incidental taking of small numbers of marine mammals may be 
allowed only if NMFS (through authority delegated by the Secretary) 
finds that the total taking by the specified activity during the 
specified time period will (i) have a negligible impact on the species 
or stock(s) and (ii) not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant). Further, the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such taking 
must be set forth, either in specific regulations or in an 
authorization.
    The allowance of such incidental taking under section 101(a)(5)(A), 
by harassment, serious injury, death, or a combination thereof, 
requires that regulations be established. Subsequently, a Letter of 
Authorization may be issued pursuant to the prescriptions established 
in such regulations, providing that the level of taking will be 
consistent with the findings made for the total taking allowable under 
the specific regulations. Under section 101(a)(5)(D), NMFS may 
authorize such incidental taking by harassment only, for periods of not 
more than one year, pursuant to requirements and conditions contained 
within an Incidental Harassment Authorization (IHA). The establishment 
of prescriptions through either specific regulations or an 
authorization requires notice and opportunity for public comment.
    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.'' 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].

Summary of Request

    On December 2, 2015, NMFS received an application from the 
Municipality of Skagway (MOS) for the taking of marine mammal 
incidental to reconstructing the Skagway ore terminal (SOT) in Skaway 
Harbor, Skagway, Alaska, referred to as the Skagway Gateway Initiative 
project. On January 22, 2016 and March 14, 2016, and March 17, 2016 
NMFS received revised applications. NMFS determined that the 
application was adequate and complete on April 1, 2016. MOS proposes to 
conduct in-water work that may incidentally harass marine mammals 
(i.e., pile driving and removal) at the ore terminal. Take, by Level B 
Harassment, of individuals of six species of marine mammals is 
anticipated to results from the specified activity. This IHA would be 
valid from July 1, 2016 through June 30, 2017.

Description of the Specified Activity

Overview

    The MOS is seeking an IHA for work that includes demolition of 
existing in-water and over-water infrastructure including in-water 
removal of timber, steel, and concrete piling; mechanical dredging of 
and upland beneficial reuse or disposal of contaminated sediments in 
the Skagway Ore Terminal (SOT)

[[Page 26631]]

basin of Skagway Harbor; and construction of new infrastructure 
including a bulkhead wall at the northern end of the Terminal basin, a 
wharf structure at the western edge of the SOT, an ore loader and 
supporting infrastructure, seven new or refurbished moorage dolphins 
and associated catwalks, and a concrete floating dock and associated 
gangways (or an additional three moorage dolphins and catwalks, 
depending on funding). Development of this new infrastructure involves 
a combination of in-water, over-water, and upland work.
    The project's timing, duration, and specific types of activities 
(such as pile driving and dredging) may result in the incidental taking 
by acoustical harassment of marine mammals protected under the MMPA. 
The MOS is requesting an IHA for six marine mammal species: Harbor seal 
(Phoca viutlina), Steller sea lion (Eumetopias jubatus), harbor 
porpoise (Phocoena phocoena), Dall's porpoise (Phocoenoides dalli), 
killer whale (Orcinus orca), and humpback whale (Megaptera 
novaeangliae), that may occur in the vicinity of the project.

Dates and Duration

    Pile installation and extraction associated with the SOT project 
will begin no sooner than July 01, 2016 and will be completed no later 
than June 30, 2016 (1 year following IHA issuance). Pile driving 
activities are proposed to occur from the end of July to the beginning 
of October 2016 and again in March 2017 for a total of about 155 hours 
over the course of approximately 73 days in 2016 and 2017. Pile removal 
will occur in July 2016 and December 2016 to January 2017 for a total 
of about 117 hours over the course of approximately 39 days in 2016 and 
2017. Dredging will occur from January through the beginning of March 
2017, for a total of about 400 hours over 40 days in the winter of 
2017.
    To minimize impacts to Hooligan (Thaleichtys pacificus), Pacific 
herring (Clupea pallasii), capelin (Mallotus catervarius), and other 
forage fish species that are part of the prey base for many marine 
mammals including seals, sea lions, and baleen whales, in-water 
construction timing has been planned to avoid major spawning and 
migration times (April 1 through May 31).

Specified Geographic Region

    The proposed activities will occur at the SOT located in Skagway 
Harbor, Alaska, on the Taiya Inlet/Lynn Canal water body. The Project 
is located in Section 26 and 35, T 30 S, R 59 E, Copper River Meridian; 
United States Geological Survey Quad Map Skagway B-1; Latitude 59.45 
degrees North (N), Longitude 135.31 degrees West (W) (see Figure 1 of 
the MOS's application). Skagway Harbor is located at the southwestern 
end of the 2.5-mile-long Skagway River valley. The Skagway River 
empties into Taiya Inlet at the head of Lynn Canal, the northernmost 
fjord on the Inside Passage of the south coast of Alaska. Pullen Creek 
empties into the inlet on the southeast side of the valley.

Detailed Description of Activities

    The proposed action for this IHA request includes demolition of 
existing in- and overwater infrastructure including in-water removal of 
timber, steel, and concrete piling; mechanical dredging of and upland 
beneficial reuse or disposal of contaminated sediments in the SOT basin 
(Terminal basin) of Skagway Harbor; and construction of new 
infrastructure including a bulkhead wall at the northern end of the 
Terminal basin, a wharf structure at the western edge of the SOT, an 
ore loader and supporting infrastructure, seven new or refurbished 
moorage dolphins and associated catwalks, and a concrete floating dock 
and associated gangways (or an additional three moorage dolphins and 
catwalks, depending on funding).
    The SOT was constructed in 1968, and pier access accommodates 
vessels in the 35,000 DWT class (AIDEA 2008). The Port of Skagway has 
provided key transportation import/export capacity for the Yukon for 
over a century. The construction activities are designed to upgrade and 
enhance current shipping needs and increase the capacity and efficiency 
of the existing terminal for shipment and export. It will spring open 
new international business from cruise ships, container traffic, mining 
resources, and energy production, revitalizing investment in Skagway, 
the Port and the Region.
    Existing structures to be demolished include the eastern extent of 
the timber pier, the ore loader and concrete and steel foundation, fuel 
infrastructure (timber dock and piping), the concrete Alaska Marine 
Lines (AML) pier, and up to five concrete and steel moorage dolphins 
(see sheets 1 and 2 of the MOS's application). The existing 
infrastructure will be demolished using heavy, land- or water-based 
(i.e., from a barge) equipment. The contractor will be required to 
implement best management practices (BMPs) to minimize environmental 
impacts from demolition. In total, demolition actions are expected to 
take 39 days to complete.
    Demolition of the infrastructure will generally occur as follows: 
Above-water infrastructure, including concrete pads, timber decking, 
pile caps, utilities, and piping will be removed. Timber piles will 
then be extracted entirely using a vibratory hammer or broken off at 
the mudline if extraction is not practical. The timber piles will be 
removed as both a source control measure (i.e., through removal of 
creosote-treated timber piles) and as a necessary step to perform 
environmental dredging in this area. Table 1 shows the total number of 
piles to be removed during demolition.

          Table 1--Number of Piles To Be Removed via Demolition
------------------------------------------------------------------------
                                             Number of
                                             Creosote-       Number of
                                           treated piles  steel piles to
                                           to be removed    be removed
------------------------------------------------------------------------
Timber Pier.............................             400              50
Ore Loader..............................               0              50
AML Pier................................               0              15
Fuel Infrastructure.....................               0               4
Moorage Dolphins2.......................               0               0
                                         -------------------------------
    Total...............................             400             119
------------------------------------------------------------------------


[[Page 26632]]

    The vertical and horizontal boundaries of the proposed dredging 
were designed to remove impacted sediments (i.e., sediments with metals 
and/or polycyclic aromatic hydrocarbon (PAH) concentrations exceeding 
the sediment cleanup objectives [SCOs]). The SCOs were chosen to be the 
cleanup objective level based on discussions in the April 13, 2015, 
meeting between Bruce Wanstall (ADEC), Dr. Chad Gubala (MOS), and Derek 
Koellmann (Anchor QEA). The current estimated dredge volume (including 
a 1-foot over-dredge to account for equipment tolerances) is 41,000 
ft\2\, and the associated approximate surface area is 21,245 ft\2\, 
pending final design and geotechnical and structural considerations, 
for a total surface area of 62,245 ft\2\ to be removed. The estimated 
contaminated material planned to be removed is 17,300 cubic yards. An 
additional 9,000 cubic yards of uncontaminated material may be dredged 
for the installation of the floating dock. Pending the outcome of a 
treatability study, dredged sediments will either be beneficially 
reused in upland areas or transported to a suitable upland landfill at 
the discretion of ADEC.
    All dredging will be performed using up-to a seven-cubic-yard 
clamshell bucket. Use of an environmental bucket was considered, but 
was deemed infeasible given the nature and composition of the sediments 
to be dredged. As noted in the demolitions section, specific overwater 
structures are planned to be demolished prior to the start of dredging. 
In total, dredging actions are expected to take 40 days to complete.
    Construction of new in- and overwater infrastructure is proposed, 
including the AML bulkhead wall, wharf structure, and ore loader. In 
addition, either a concrete floating dock or additional moorage 
dolphins connected by a catwalk will be constructed. Whether the 
concrete floating dock or moorage dolphins and catwalk are constructed 
depends on available funding. All piles will be installed using a 
vibratory and/or impact hammer. Piles to be installed are summarized in 
Table 2.

                                                             Table 2--Piles To Be Installed
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                                                                                       Pile size and number                               Square footage
                    Project component                    --------------------------------------------------------------------------------  of sea floor
                                                               24 in           36 in           48 in           60 in           Total          impacts
--------------------------------------------------------------------------------------------------------------------------------------------------------
AML Bulkhead Wall.......................................               0               0               0               0               0               0
Wharf Structure at Ore Dock.............................              16              20               4               0              40           241.9
Ore Loader and Foundation...............................               0              58               0               0              58           410.0
Moorage Dolphins and Catwalk............................               0              70               0               0              70           494.8
Fuel Infrastructure.....................................               0              17               0               0              17           120.2
Concrete Floating Dock Structure........................               3              14               0               7              21           245.8
                                                         -----------------------------------------------------------------------------------------------
    Total, Concrete Floating Dock.......................              19             179               4               7             209         1,512.7
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The proposed wharf bulkhead wall will be constructed of steel sheet 
pile walls in the form of a rectangle of approximately 220 by 75 feet 
(16,500 square feet). The top of the walls will be at approximately 30 
feet above MLLW, and the future bottom of the walls at a depth of -4 
feet MLLW. The structure will be filled with 2,000 to 4,000 cubic yards 
of suitable dredged material, of which 150 to 300 cubic yards will be 
placed below MHHW. The ground surface where fill will be placed is 
primarily above MHHW. Only fill placed in the southeastern corner of 
the structure will be within the intertidal zone. The steel sheet pile 
will be installed using a vibratory and/or impact hammer.
    The proposed AML pier will be a steel and concrete structure 
abutting the new wharf structure. The pier will be 65 by 30 feet, 
supported by twenty 36-inch-diameter steel piles. Finished height will 
be 30 feet above MLLW. Piles will be installed with a vibratory and/or 
impact hammer.
    The proposed AML ramp will be a steel ramp of 96 by 23 feet 
supported by four 48-inch-diameter steel guide piles and sixteen 24-
inch-diameter steel piles. Finished height will be 30 feet above MLLW. 
The ramp will be installed by crane.
    A new ore loader is proposed in the harbor, including a loader, 
foundation, and access platform. The proposed ore loader foundation 
will be a steel and concrete structure, 50 by 50 feet and supported by 
fifty 36-inch-diameter steel piles. Finished height will be 30 feet 
above MLLW. Piles will be installed with a vibratory and/or impact 
hammer.
    The proposed access platform will connect the ore loader to the Ore 
Terminal uplands. It will be a steel and concrete structure, 90 by 15 
feet, and supported by twenty 36-inch-diameter steel piles. Finished 
height will be 30 feet above MLLW. Only the eastern 40 feet of length 
and eight piles will be over the intertidal or subtidal zones (the 
remainder will be above and tied into the uplands). Piles will be 
installed with a vibratory and/or impact hammer.
    The concrete dock and seven moorage dolphins (see Section 2.2.4.5 
of the MOS's application) or up to 10 moorage dolphins will be 
installed depending on funding. A concrete floating dock is proposed 
for the southern end of the project area, including the dock, a 
transfer bridge, a pile-supported pedestrian platform, and a pedestrian 
gangway. The proposed floating dock will be a 300-by-50-foot concrete 
structure supported by seven 60-inch- diameter piles and fourteen 36-
inch-diameter piles. The finished height will vary with the tide; the 
dock will have approximately 7 feet of freeboard above the waterline. 
Piles will be installed with a vibratory and/or impact hammer.
    The proposed transfer bridge will be a 200-by-19-foot steel 
structure supported by a concrete abutment founded on ten 24-inch-
diameter piles placed above the intertidal zone. The top of the ramp 
will be 30 feet above MLLW and the bottom of the ramp will be supported 
by the floating dock. Only the eastern 150 feet of length will be over 
the intertidal or subtidal zones (the remainder will be above and tied 
into the uplands). The ramp will be installed by crane.
    The proposed pedestrian platform will be a 25-by-55-foot concrete 
structure, placed adjacent to the existing timber walkway that will 
remain after the ore dock demolition. Finished height will be 30 feet 
above MLLW. The pedestrian platform will be supported on six 24-inch-
diameter steel piles. Only the eastern 10 feet and three piles of this 
structure will be over the intertidal or subtidal zones (the remainder 
will be above and tied into the uplands).

[[Page 26633]]

    The proposed pedestrian gangway will be a 150-by-8-foot steel 
structure that spans between the pedestrian platform and the concrete 
floating dock. The top of the ramp will be 30 feet above MLLW and the 
bottom of the ramp will be supported by the floating dock. The full 
length of the pedestrian gangway will be over the intertidal or 
subtidal zones. It will be installed by crane.
    As many as 10 new moorage dolphins may be constructed, along with 
connecting catwalks, located as follows:
     Up to two dolphins and a catwalk 200 by 6 feet extending 
from the AML bulkhead wall toward the AML ramp;
     Up to five dolphins and a catwalk 400 by 6 feet extending 
north and south from the ore loader; and
     Up to three dolphins and a catwalk 300 by 6 feet north of 
the existing concrete pier, if the concrete floating dock is not 
constructed.
    Each dolphin will consist of a 15-foot-square steel and concrete 
superstructure atop ten 36-inch steel piles.
    Each catwalk will be a 6-foot-wide steel structure, supported by 
the dolphins. Finished height will be 30 feet above MLLW. Dolphins will 
be installed by vibratory and/or impact hammer and the catwalk will be 
installed by crane.
    A new fuel manifold and fuel lines will be constructed on a pier 
extending from the ore loader platform infrastructure. The proposed 
fuel pier will be a steel and concrete structure. The approach pier 
will be 60 by 15 feet, supported by eight 36-inch-diameter steel piles. 
The fuel pier will be 30 by 30 feet supported by nine 36-inch-diameter 
steel piles. Finished height will be 30 feet above MLLW. Piles will be 
installed with a vibratory and/or impact hammer.

Description of Marine Mammals in the Area of the Specified Activity

    Marine waters near Skagway in the Taiya inlet and the larger Lynn 
Canal support many species of marine mammals, including pinnipeds and 
cetaceans; however, the number of species that may regularly occur near 
the project area is 10 marine mammal species (Table 3). For the purpose 
of this IHA, the region of activity is defined as Taiya Inlet as 
acoustic impacts from the project are not anticipated to extend beyond 
the inlet into the adjacent Lynn Canal. Some species in this area are 
not expected to be impacted by the project activities, due to habitat 
preference including the gray whale, sperm whale, and the Pacific 
white-sided dolphin, and are therefore not considered further in this 
document after this section. Sperm whales have been observed in 
southeast Alaska with more frequency in recent years and have been 
tracked in Lynn Canal (seaswap.info). It is unknown whether they occur 
as far north as Taiya inlet and the action area (J. Moran personal 
communication, March 2016); however, there are no documented sightings 
in the area (seaswap.info). This species prefers deeper waters, and are 
unlikely to occur in the narrow inlets near Skagway. Gray whale 
sightings in the portion of Southeast Alaska are very rare; there have 
only been eight sightings since 1997, none of which were in Taiya Inlet 
or Lynn Canal. Pacific white-sided are also considered rare in the 
action area, with habitat preferences in southern waters of southeast 
Alaska. While minke whales may occur in the action area, our analysis 
and take calculation suggest that this species will not be taken for 
this activity (zero calculated take); therefore, no take of this 
species will be authorized. There are six marine mammal species 
documented in the waters of Taiya Inlet/Lynn Canal (Dahlheim et al. 
2009; Allen and Angliss 2014; Muto and Angliss 2015) for which take is 
requested.
    One of the species, the harbor seal, is known to consistently occur 
near the SOT; however the closest haul out site is six miles away. 
Moderate to high abundances of Steller sea lions are also known to 
seasonally occupy the inlet, with the closest haul out more than 22 
miles away from construction activities. Several humpback whales have 
been observed within Taiya Inlet, sometimes close to Skagway, during 
non-winter months. The remaining four species (harbor porpoise, Dall's 
porpoise, killer whale, and minke whale) may occur in Taiya Inlet/Lynn 
Canal, but less frequently and farther from the SOT.

                      Table 3--Marine Mammal Species Likely To Occur Near the Project Area
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                                     Stock(s)
         Species name               abundance           ESA * status        MMPA ** status        Occurrence
                                   estimate \1\
----------------------------------------------------------------------------------------------------------------
                      Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
----------------------------------------------------------------------------------------------------------------
                                             Family Balaenopteridae
----------------------------------------------------------------------------------------------------------------
Humpback whale (Megaptera       Central North      Endangered............  Strategic,        Rare.
 novaeangliae).                  Pacific Stock:                             depleted.
                                 10,252.
Minke whale (Balaenoptera       Alaska stock: N/A  Not listed............  Not strategic...  Unlikely.
 acutorostrata).
----------------------------------------------------------------------------------------------------------------
                                   Order Cetartiodactyla--Cetacea--Superfamily
----------------------------------------------------------------------------------------------------------------
                                              Family Eschrichtiidae
----------------------------------------------------------------------------------------------------------------
Gray whale (Eschrichtius        Eastern North      Not listed............  Not strategic,    Unlikely.
 robustus).                      Pacific stock:                             non-depleted.
                                 20,990.
----------------------------------------------------------------------------------------------------------------
                                   Order Cetartiodactyla--Cetacea--Superfamily
----------------------------------------------------------------------------------------------------------------
                                              Family Physeteroidea
----------------------------------------------------------------------------------------------------------------
Sperm whale (Physeter           North Pacific      Endangered............  Strategic,        Unlikely.
 macrocephalus).                 stock: N/A.                                depleted.
----------------------------------------------------------------------------------------------------------------

[[Page 26634]]

 
                                   Order Cetartiodactyla--Cetacea--Superfamily
----------------------------------------------------------------------------------------------------------------
                                               Family Delphinidae
----------------------------------------------------------------------------------------------------------------
Killer whale (Orcinus orca)...  Alaska stock:      Not listed............  Not Strategic,    Infrequent.
                                 2,347.                                     non-depleted.
                                Northern resident
                                 stock: 261.
                                Gulf of Alaska
                                 stock: 587.
                                West coast
                                 transient stock:
                                 243.
Pacific white-sided dolphin     North Pacific      Not listed............  Not Strategic,    Unlikely.
 (Lagenorhynchus obliquidens).   stock: 26,880.                             non-depleted.
----------------------------------------------------------------------------------------------------------------
                                   Order Cetartiodactyla--Cetacea--Superfamily
----------------------------------------------------------------------------------------------------------------
                                               Family Phocoenidae
----------------------------------------------------------------------------------------------------------------
Dall's porpoise (Phocoenoides   Alaska stock:      Not listed............  Not strategic,    Rare.
 dalli).                         83,400.                                    non-depleted.
Harbor porpoise (Phocoena       Southeast AK:      Not listed............  Strategic, non-   Likely.
 phocoena).                      11,146.                                    depleted.
----------------------------------------------------------------------------------------------------------------
                                           Order Carnivora--Pinnipedia
----------------------------------------------------------------------------------------------------------------
                                                 Family Phocidae
----------------------------------------------------------------------------------------------------------------
Harbor seal (Phoca vitulina)..  Lynn Canal/        Not listed............  Not strategic-    Likely.
                                 Stephens Passage                           non-depleted.
                                 Stock: 9,478.
----------------------------------------------------------------------------------------------------------------
                                           Order Carnivora--Pinnipedia
----------------------------------------------------------------------------------------------------------------
                                                Family Otariidae
----------------------------------------------------------------------------------------------------------------
Steller sea lion (Eumetopias    wDPS:49,497......  Endangered............  Strategic,        Likely.
 jubatus).                      eDPS: 60,131-                               depleted.
                                 74,448.
----------------------------------------------------------------------------------------------------------------
\1\ 2015 draft marine mammal Stock Assessment Reports at https://www.nmfs.noaa.gov/pr/sars/species.htm.
* Endangered Species Act.
** Marine Mammal Protection Act.

Cetaceans

Humpback whale
    The humpback whale is distributed worldwide in all ocean basins. In 
winter, most humpback whales occur in the subtropical and tropical 
waters of the Northern and Southern Hemispheres, and migrate to high 
latitudes in the summer to feed. The historic summer feeding range of 
humpback whales in the North Pacific encompassed coastal and inland 
waters around the Pacific Rim from Point Conception, California, north 
to the Gulf of Alaska and the Bering Sea, and west along the Aleutian 
Islands to the Kamchatka Peninsula and into the Sea of Okhotsk and 
north of the Bering Strait (Zenkovich 1954, Johnson and Wolman 1984). 
The winter range includes the main islands of the Hawaiian archipelago, 
with the greatest concentration along the west side of Maui. In Mexico, 
the winter range includes waters around the southern part of the Baja 
California peninsula, the central portions of the Pacific coast of 
mainland Mexico, and the Revillagigedos Islands off the mainland coast. 
The winter range also extends from southern Mexico into Central 
America, including Guatemala, El Salvador, Nicaragua, and Costa Rica 
(Calambokidis et al., 2008).
    There are three stocks of humpback whales in the North Pacific: (1) 
The California/Oregon/Washington and Mexico stock, consisting of 
winter/spring populations in coastal Central America and coastal Mexico 
which migrate to the coast of California to southern British Columbia 
in summer/fall (Calambokidis et al. 1989, Steiger et al. 1991, 
Calambokidis et al. 1993); (2) the central North Pacific stock, 
consisting of winter/spring populations of the Hawaiian Islands which 
migrate primarily to northern British Columbia/Southeast Alaska, the 
Gulf of Alaska, and the Bering Sea/Aleutian Islands (Perry et al. 1990, 
Calambokidis et al. 1997); and (3) the western North Pacific stock, 
consisting of winter/spring populations off Asia which migrate 
primarily to Russia and the Bering Sea/Aleutian Islands. Information 
from the SPLASH (Structure of Populations, Levels of Abundance, and 
Status of Humpbacks) project mostly confirms this view of humpback 
whale distribution and movements in the North Pacific; however, the 
full SPLASH results suggest the current view of population structure is 
incomplete. A revision of population structure in the North Pacific 
will be considered when the full genetic results from the SPLASH 
project are available. The central North Pacific stock is the only 
stock that is found near the project activities.
    The current abundance estimate for the Central North Pacific stock 
is 10,252 individuals (Muto and Angliss, 2015). This stock is 
designated as strategic and depleted under the MMPA. Humpback whales 
are currently listed as endangered range-wide under the ESA. The status 
and population structure of humpback whales is currently under review 
by NMFS as part of a global status review of the species (Muto and 
Angliss, 2015). This stock of humpback whales is growing, with the 
growth rate estimated to be seven percent (Allen and Angliss, 2014). 
The current PBR for this stock is 173 individuals. Entanglement from 
fishing gear and ship strikes remain the top threats for humpback 
whales, with an estimated

[[Page 26635]]

annual mortality and serious injury rate of 23 animals (Muto and 
Angliss, 2015).
Killer Whale
    Killer whales have been observed in all oceans and seas of the 
world, but the highest densities occur in colder and more productive 
waters found at high latitudes. Killer whales are found throughout the 
North Pacific, and occur along the entire Alaska coast, in British 
Columbia and Washington inland waterways, and along the outer coasts of 
Washington, Oregon, and California (Allen and Angliss, 2013).
    Based on data regarding association patterns, acoustics, movements, 
and genetic differences, eight killer whale stocks are now recognized: 
(1) The Alaska Resident stock; (2) the Northern Resident stock; (3) the 
Southern Resident stock; (4) the Gulf of Alaska, Aleutian Islands, and 
Bering Sea Transient stock; (5) the AT1 Transient stock; (6) the West 
Coast transient stock, occurring from California through southeastern 
Alaska; and (7) the Offshore stock, and (8) the Hawaiian stock. Only 
the Alaska resident; Northern resident; Gulf of Alaska, Aleutian 
Islands, and Bering Sea Transient (Gulf of Alaska transient); and the 
West coast transient stocks are considered in this application because 
other stocks occur outside the geographic area under consideration. Any 
of these four stocks could be seen in the action area; however, the 
Northern resident stock is most likely to occur in the area.
    The Alaska resident stock is found from southeastern Alaska to the 
Aleutian Islands and Bering Sea. Intermixing of Alaska residents have 
been documented among the three areas, at least as far west as the 
eastern Aleutian Islands (Allen and Angliss, 2013). Combining the 
counts of known `resident' whales gives a minimum number of 2,347 
(Southeast Alaska + Prince William Sound + Western Alaska; 121 + 751 + 
1,475) killer whales belonging to the Alaska Resident stock (Allen and 
Angliss 2013). At present, reliable data on trends in population 
abundance for the entire Alaska resident stock of killer whales are 
unavailable. PBR is 23.4 animals. Fishery interactions are a main 
threat to this stock. This stock is not designated as depleted or 
classified as strategic under the MMPA, and is not listed under the 
ESA.
    The Northern resident stock occurs from Washington State through 
part of southeastern Alaska. The Northern Resident stock is a 
transboundary stock, and includes killer whales that frequent British 
Columbia, Canada and southeastern Alaska (Dahlheim et al., 1997; Ford 
et al., 2000). The population estimate for this stock is currently 261 
whales (Allen and Angliss, 2013). This population is increasing, with 
an average of 2.1 percent annual increase over a 36 year time period 
(Ellis et al., 2011). PBR for this stock is 1.96 animals. This stock is 
not designated as depleted or strategic under the MMPA, and is not 
listed as threatened or endangered under the ESA.
    The Gulf of Alaska transient stock occurs mainly from Prince 
William Sound through the Aleutian Islands and Bering Sea. Current 
abundance estimate for this stock is 587 animals (Allen and Angliss, 
2013). PBR is 5.87 animals per year (Allen and Angliss, 2013). Current 
trends for this stock are unavailable, but the stock is not designated 
as depleted or strategic under the MMPA and is not listed under the 
ESA.
    The West coast transient stock includes animals that occur in 
California, Oregon, Washington, British Columbia and southeastern 
Alaska. Current abundance estimate for this stock is 243 animals, which 
should be considered a minimum count for this stock (Allen and Angliss, 
2013). PBR is 2.4 animals per year (Allen and Angliss, 2013). No 
reliable estimates of population trends are available, but this stock 
is not designated as depleted or strategic under the MMPA, and is not 
listed under the ESA.
    Additional information on the biology and local distribution of 
these species can be found in the NMFS Marine Mammal Stock Assessment 
Reports, which may be found at: https://www.nmfs.noaa.gov/pr/species/.
Dall's Porpoise
    Dall's porpoise are widely distributed across the entire North 
Pacific Ocean. They are found over the continental shelf adjacent to 
the slope and over deep (2,500+ m) oceanic waters. They have been 
sighted throughout the North Pacific as far north as 65[deg] N. 
(Buckland et al. 1993). Throughout most of the eastern North Pacific 
they are present during all months of the year, although there may be 
seasonal onshore-offshore movements along the west coast of the 
continental United States (Loeb 1972), and winter movements of 
populations out of Prince William Sound and areas in the Gulf of Alaska 
and Bering Sea (NMFS, unpubl. data, National Marine Mammal Laboratory). 
The stock structure of eastern North Pacific Dall's porpoise is not 
adequately understood at this time, but based on patterns of stock 
differentiation in the western North Pacific, where they have been more 
intensively studied, it is expected that separate stocks will emerge 
when data become available.
    Currently one stock of Dall's porpoise is recognized in Alaskan 
waters, while Dall's porpoise along the west coast of the continental 
U.S. from California to Washington comprise a separate stock (Allen and 
Angliss, 2012). The current abundance estimate for the Alaska stock is 
83,400 animals (Muto and Angliss, 2015). PBR for this stock is 
currently undetermined, and population trends are unknown; however, 
this stock is not designated as depleted or strategic under the MMPA, 
and is not listed under the ESA (Allen and Angliss, 2012).
Harbor Porpoise
    The harbor porpoise inhabits temporal, subarctic, and arctic 
waters. In the eastern North Pacific, harbor porpoises range from Point 
Barrow, Alaska, to Point Conception, California. Harbor porpoise 
primarily frequent coastal waters and occur most frequently in waters 
less than 100 m deep (Hobbs and Waite 2010). They may occasionally be 
found in deeper offshore waters.
    In Alaska, harbor porpoises are currently divided into three 
stocks, based primarily on geography. These are (1) the Southeast 
Alaska stock--occurring from the northern border of British Columbia to 
Cape Suckling, Alaska, (2) the Gulf of Alaska stock--occurring from 
Cape Suckling to Unimak Pass, and (3) the Bering Sea stock--occurring 
throughout the Aleutian Islands and all waters north of Unimak Pass 
(Allen and Angliss 2014). Only the Southeast Alaska stock is considered 
in this application because the other stocks are not found in the 
geographic area under consideration.
    Harbor porpoises are neither designated as depleted under the MMPA 
nor listed as threatened or endangered under the ESA. Because the most 
recent abundance estimate is 14 years old and information on incidental 
harbor porpoise mortality in commercial fisheries is not well 
understood, the Southeast Alaska stock of harbor porpoise is classified 
as strategic. Population trends and status of this stock relative to 
optimum sustainable population size are currently unknown. The 
Southeast Alaska stock is currently estimated at 11,146 individuals 
(Muto and Angliss 2015). No reliable information is available to 
determine trends in abundance.

[[Page 26636]]

Pinnipeds

Harbor Seal
    Harbor seals range from Baja California north along the west coasts 
of Washington, Oregon, California, British Columbia, and Southeast 
Alaska; west through the Gulf of Alaska, Prince William Sound, and the 
Aleutian Islands; and north in the Bering Sea to Cape Newenham and the 
Pribilof Islands. They haul out on rocks, reefs, beaches, and drifting 
glacial ice, and feed in marine, estuarine, and occasionally fresh 
waters. Harbor seals generally are nonmigratory, with local movements 
associated with such factors as tides, weather, season, food 
availability, and reproduction (Scheffer and Slipp 1944, Fisher 1952, 
Bigg 1969, 1981, Hastings et al. 2004).
    In 2010, harbor seals in Alaska were partitioned into 12 separate 
stocks based largely on genetic structure (Allen and Angliss 2012). The 
12 stocks of harbor seals identified in Alaska are (1) the Aleutian 
Islands stock, (2) the Pribilof Islands stock, (3) the Bristol Bay 
stock, (4) the North Kodiak stock, (5) the South Kodiak stock, (6) the 
Prince William Sound stock, (7) the Cook Inlet/Shelikof stock, (8) the 
Glacier Bay/Icy Strait stock, (9) the Lynn Canal/Stephens Passage 
stock, (10) the Sitka/Chatham stock, (11) the Dixon/Cape Decision 
stock, and (12) the Clarence Strait stock. Only the Lynn Canal/Stephens 
stock is considered for these construction activities. The range of 
this stock ranges north along the east and north coast of Admiralty 
Island from the north end of Kupreanof Island through Lynn Canal, 
including Taku Inlet, Tracy Arm, and Endicott Arm, and reaching as far 
north as Taiya, Lutak, and Chilkat Inlets (Allen and Angliss, 2012).
    The current statewide abundance estimate for Alaskan harbor seals 
is 205,090, based on aerial survey data collected during 1998-2011 
(Muto and Angliss, 2015). The abundance estimate for the Lynn Canal/
Stephens Passage stock is 9,478 (Muto and Angliss 2015). The current 
(2007-2011) estimate of the population trend information for this stock 
is -176 seals per year, with a probability that the stock is decreasing 
(Muto and Angliss, 2015). PBR is 155 animals per year.
    Harbor seals are included in subsistence harvests. From 2011-2012, 
an average of 50 animals from this stock were harvested each year, 
which is higher than previous estimates of 30 animals, on average, per 
year from 2004-2008 (Muto and Angliss, 2015). Entanglement is the 
biggest contributor to their annual human-caused mortality. Lynn Canal/
Stephens Passage harbor seals are not listed as depleted or strategic 
under the MMPA, and are not listed under the ESA.
Steller Sea Lion
    The Steller sea lion is a pinniped and the largest of the eared 
seals. Steller sea lion populations that primarily occur west of 
144[deg] W. (Cape Suckling, Alaska) comprise the western Distinct 
Population Segment (wDPS), while all others comprise the eastern DPS 
(eDPS); however, there is regular movement of both DPSs across this 
boundary (Muto and Angliss, 2015). Both of these populations may occur 
in the action area. Steller sea lions were listed as threatened range-
wide under the ESA on 26 November 1990 (55 Federal Register [FR] 
49204). Steller sea lions were subsequently partitioned into the 
western and eastern DPSs in 1997 (Allen and Angliss 2010), with the 
wDPS being listed as endangered under the ESA and the eDPS remaining 
classified as threatened (62 FR 24345) until it was delisted in 
November 2013. In August 1993, NMFS published a final rule designating 
critical habitat for the Steller sea lion as a 20 nautical mile buffer 
around all major haul-outs and rookeries, as well as associated 
terrestrial, air and aquatic zones, and three large offshore foraging 
areas (50 CFR 226.202). There is no Steller sea lion critical habitat 
in the area.
    The range of the Steller sea lion includes the North Pacific Ocean 
rim from California to northern Japan, with centers of abundance and 
distribution in the Gulf of Alaska and Aleutian Islands (Muto and 
Angliss, 2015). Steller sea lions forage in nearshore and pelagic 
waters where they are opportunistic predators. They feed primarily on a 
wide variety of fishes and cephalopods. Steller sea lions use 
terrestrial haulout sites to rest and take refuge. They also gather on 
well-defined, traditionally used rookeries to pup and breed. These 
habitats are typically gravel, rocky, or sand beaches; ledges; or rocky 
reefs (Allen and Angliss, 2013).
    The current abundance estimate for the wDPS in Alaska is 49,497 sea 
lions, and between 60,131-74,448 animals for the eDPS (Muto and Angliss 
2015). The wDPS of Steller sea lions declined approximately 75 percent 
from 1976 to 1990. Factors that may have contributed to this decline 
include (1) incidental take in fisheries, (2) legal and illegal 
shooting, (3) predation, (4) contaminants, (5) disease, and (6) climate 
change. Non-pup Steller sea lion counts at trend sites in the wDPS 
increased 11 percent during 2000-2004. These counts were the first 
region-wide increases for the wDPS since standardized surveys began in 
the 1970s, and were due to increased or stable counts in all regions 
except the western Aleutian Islands. During 2004-2008, western Alaska 
non-pup counts increased only 3 percent; eastern Gulf of Alaska (Prince 
William Sound area) counts were higher; counts from the Kenai Peninsula 
through Kiska Island, including Kodiak Island, were stable; and western 
Aleutian counts continued to decline (Allen and Angliss 2010). Current 
PBR for the wDPS is 297 animals, and PBR for the eDPS is currently 
unavailable (Muto and Angliss, 2015).
    Steller sea lions are included in Alaska subsistence harvests. The 
mean annual take of Steller sea lions is 199 from 2004-2013 (Muto and 
Angliss, 2015). Entanglements in fishing gear and marine debris, and 
interactions with fishing gear are sources of mortality and serious 
injury for Steller sea lions.

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

    This section includes a summary and discussion of the ways that the 
specified activity (e.g. pile driving, pile removal), including 
potential mitigation activities, associated with the reconstruction of 
the SOT may impact marine mammals and their habitat. Mitigation 
measures will reduce impacts to marine mammals from the project 
activities. Please refer to the Proposed Mitigation section for more 
information. The Estimated Take by Incidental Harassment section later 
in this document will include an analysis of the number of individuals 
that are expected to be taken by this activity. The Negligible Impact 
Analysis section will include the analysis of how this specific 
activity will impact marine mammals and 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 this activity on the reproductive success or 
survivorship of individuals and from that on the affected marine mammal 
populations or stocks. In the following discussion, we provide general 
background information on sound and marine mammal hearing before 
considering potential effects to marine mammals from sound produced by 
pile extraction, vibratory pile driving, and impact pile driving.

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

[[Page 26637]]

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 and attenuate (decrease) more 
rapidly in shallower water. 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 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 [mu]Pa and all airborne sound levels in this document are 
referenced to a pressure of 20 [mu]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 
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.
    The underwater acoustic environment in the SOT is likely to be 
dominated by noise from day-to-day port and vessel activities. The Port 
of Skagway has provided key transportation import/export capacity for 
the Yukon and pier access accommodates vessels in the 35,000 DWT class 
(AIDEA 2008). When underway, these sources can create noise between 20 
Hz and 16 kHz (Lesage et al., 1999), with broadband noise levels up to 
180 dB. While there are no current measurements of ambient noise levels 
in harbor, it is likely that levels within the harbor periodically 
exceed the 120 dB threshold and, therefore, that the high levels of 
anthropogenic activity in the basin create an environment far different 
from quieter habitats where behavioral reactions to sounds around the 
120 dB threshold have been observed (e.g., Malme et al., 1984, 1987).
    High levels of vessel traffic are known to elevate background 
levels of noise in the marine environment. For example, continuous 
sounds for tugs pulling barges have been reported to range from 145 to 
166 dB re 1 [mu]Pa rms at 1 meter from the source (Miles et al. 1987; 
Richardson et al. 1995; Simmonds et al. 2004). Ambient underwater noise 
levels in the SOT project area are both variable and relatively high, 
and are expected to mask some sounds of drilling, pile installation, 
and pile extraction.
    In-water construction activities associated with the project 
include vibratory pile driving and removal, and impact pile driving. 
There are two general categories of sound types: Impulse and non-pulse 
(defined below). Vibratory pile driving is considered to be continuous 
or non-pulsed while

[[Page 26638]]

impact pile driving is considered to be an impulse or pulsed sound 
type. 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 (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 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).
    The likely or possible impacts of the proposed pile driving program 
at SOT on marine mammals could involve both non-acoustic and acoustic 
stressors. Potential non-acoustic stressors could result from the 
physical presence of the equipment and personnel. Any impacts to marine 
mammals are expected to primarily be acoustic in nature. Acoustic 
stressors could include effects of heavy equipment operation, pile 
installation and pile removal at SOT.

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 
functional groups and the associated frequencies are indicated below 
(note that these frequency ranges do not necessarily correspond to the 
range of best hearing, which varies by species):
     Low frequency cetaceans (13 species of mysticetes): 
Functional hearing is estimated to occur between approximately 7 Hz and 
25 kHz (up to 30 kHz in some species), with best hearing estimated to 
be from 100 Hz to 8 kHz (Watkins, 1986; Ketten, 1998; Houser et al., 
2001; Au et al., 2006; Lucifredi and Stein, 2007; Ketten et al., 2007; 
Parks et al., 2007a; Ketten and Mountain, 2009; Tubelli et al., 2012);
     Mid-frequency cetaceans (32 species of dolphins, six 
species of larger toothed whales, and 19 species of beaked and 
bottlenose whales): Functional hearing is estimated to occur between 
approximately 150 Hz and 160 kHz with best hearing from 10 to less than 
100 kHz (Johnson, 1967; White, 1977; Richardson et al., 1995; Szymanski 
et al., 1999; Kastelein et al., 2003; Finneran et al., 2005a, 2009; 
Nachtigall et al., 2005, 2008; Yuen et al., 2005; Popov et al., 2007; 
Au and Hastings, 2008; Houser et al., 2008; Pacini et al., 2010, 2011; 
Schlundt et al., 2011);
     High frequency cetaceans (eight species of true porpoises, 
six species of river dolphins, and members of the genera Kogia and 
Cephalorhynchus; now considered to include two members of the genus 
Lagenorhynchus on the basis of recent echolocation data and genetic 
data [May-Collado and Agnarsson, 2006; Kyhn et al. 2009, 2010; Tougaard 
et al. 2010]): Functional hearing is estimated to occur between 
approximately 200 Hz and 180 kHz (Popov and Supin, 1990a,b; Kastelein 
et al., 2002; Popov et al., 2005);
     Phocid pinnipeds in water: Functional hearing is estimated 
to occur between approximately 75 Hz and 100 kHz with best hearing 
between 1-50 kHz (M[oslash]hl, 1968; Terhune and Ronald, 1971, 1972; 
Richardson et al., 1995; Kastak and Schusterman, 1999; Reichmuth, 2008; 
Kastelein et al., 2009); and
     Otariid pinnipeds in water: Functional hearing is 
estimated to occur between approximately 100 Hz and 48 kHz, with best 
hearing between 2-48 kHz (Schusterman et al., 1972; Moore and 
Schusterman, 1987; Babushina et al., 1991; Richardson et al., 1995; 
Kastak and Schusterman, 1998; Kastelein et al., 2005a; Mulsow and 
Reichmuth, 2007; Mulsow et al., 2011a, b).
    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth et al., 
2013).
    As mentioned previously in this document, ten marine mammal species 
(eight cetaceans and two pinnipeds) may occur in the project area. Of 
the six species likely to occur in the proposed project area for which 
take is requested, 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 two are classified as a high-frequency cetaceans 
(i.e., harbor porpoise and Dall's porpoise) (Southall et al., 2007). 
Additionally, harbor seals are classified as members of the phocid 
pinnipeds in water functional hearing group while Stellar 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.

[[Page 26639]]

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 MOS'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 MOS's activities may result in such effects (see below for 
further discussion). Marine mammals exposed to high-intensity sound, or 
to lower-intensity sound for prolonged periods, can experience hearing 
threshold shift (TS), which is the loss of hearing sensitivity at 
certain frequency ranges (Kastak et al., 1999; Schlundt et al., 2000; 
Finneran et al., 2002, 2005b). TS can be permanent (PTS), in which case 
the loss of hearing sensitivity is not fully recoverable, or temporary 
(TTS), in which case the animal's hearing threshold would recover over 
time (Southall et al., 2007). Repeated sound exposure that leads to TTS 
could cause PTS. In severe cases of PTS, there can be total or partial 
deafness, while in most cases the animal has an impaired ability to 
hear sounds in specific frequency ranges (Kryter, 1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward, 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several decibels above (a 40-dB threshold shift approximates 
PTS onset; e.g., Kryter et al., 1966; Miller, 1974) that inducing mild 
TTS (a 6-dB threshold shift approximates TTS onset; e.g., Southall et 
al. 2007). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulse sounds (such as 
impact pile driving pulses as received close to the source) are at 
least 6 dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level thresholds (Southall et al., 
2007). Given the higher level of sound or longer exposure duration 
necessary to cause PTS as compared with TTS, it is considerably less 
likely that PTS could occur.
    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 MOS'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, and 
none of the data published at the time of this writing concern TTS 
elicited by exposure to multiple pulses of sound.
    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

[[Page 26640]]

occurs during a time where ambient noise is lower and there are not as 
many competing sounds present. Alternatively, a larger amount and 
longer duration of TTS sustained during time when communication is 
critical for successful mother/calf interactions could have more 
serious impacts.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin [Tursiops truncatus], beluga whale [Delphinapterus 
leucas], harbor porpoise, and Yangtze finless porpoise [Neophocoena 
asiaeorientalis]) and three species of pinnipeds (northern elephant 
seal, harbor seal, and California sea lion) exposed to a limited number 
of sound sources (i.e., mostly tones and octave-band noise) in 
laboratory settings (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 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.

[[Page 26641]]

Changes in vocalization behavior in response to anthropogenic noise can 
occur for any of these modes and may result from a need to compete with 
an increase in background noise or may reflect increased vigilance or a 
startle response. For example, in the presence of potentially masking 
signals, humpback whales and killer whales have been observed to 
increase the length of their songs (Miller et al., 2000; Fristrup et 
al., 2003; Foote et al., 2004), while right whales have been observed 
to shift the frequency content of their calls upward while reducing the 
rate of calling in areas of increased anthropogenic noise (Parks et 
al., 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 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006; Teilmann 
et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus, 1996). The result of a flight response could range from 
brief, temporary exertion and displacement from the area where the 
signal provokes flight to, in extreme cases, marine mammal strandings 
(Evans and England, 2001). However, it should be noted that response to 
a perceived predator does not necessarily invoke flight (Ford and 
Reeves, 2008), and whether individuals are solitary or in groups may 
influence the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    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

[[Page 26642]]

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.
    Potential Effects of Pile Driving Sound--The effects of sounds from 
pile driving might include one or more of the following: Temporary or 
permanent hearing impairment, non-auditory physical or physiological 
effects, behavioral disturbance, and masking (Richardson et al., 1995; 
Gordon et al., 2003; Nowacek et al., 2007; Southall et al., 2007). The 
effects of pile driving 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 sound; the 
depth of the water column; 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 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 far below the thresholds that could cause TTS or the onset 
of PTS: 180 dB re 1 [mu]Pa rms for odontocetes and 190 dB re 1 [mu]Pa 
rms for pinnipeds (Table 4).
    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 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

[[Page 26643]]

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).
    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 is mostly concentrated at low frequency 
ranges, it may have less effect on high frequency echolocation sounds 
made by porpoises. The most intense underwater sounds in the proposed 
action are those produced by impact pile driving. Given that the energy 
distribution of pile driving covers a broad frequency spectrum, sound 
from these sources would likely be within the audible range of marine 
mammals present in the project area. Impact pile driving activity is 
relatively short-term, with rapid pulses occurring for approximately 
fifteen minutes per pile. The probability for impact pile driving 
resulting from this proposed action masking acoustic signals important 
to the behavior and survival of marine mammal species is low. Vibratory 
pile driving is also relatively short-term, with rapid oscillations 
occurring for approximately one and a half hours per pile. It is 
possible that vibratory pile driving resulting from this proposed 
action may mask acoustic signals important to the behavior and survival 
of marine mammal species, but the short-term duration and limited 
affected area would result in insignificant impacts from masking. Any 
masking event that could possibly rise to Level B harassment under the 
MMPA would occur concurrently within the zones of behavioral harassment 
already estimated for 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 
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 in Table 4 below. We 
recognize that pinnipeds in the water could be exposed to airborne 
sound that may result in behavioral harassment when looking with 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 incidents 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.

Vessel Interaction

    Besides being susceptible to vessel strikes, cetacean and pinniped 
responses to vessels may result in behavioral changes, including 
greater variability in the dive, surfacing, and respiration patterns; 
changes in vocalizations; and changes in swimming speed or direction 
(NRC 2003). There will be a temporary and localized increase in vessel 
traffic during construction.

Anticipated Effects on Marine Mammal Habitat

    The proposed activities at SOT 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. 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, as well as potential short-term 
effects to water and sediment quality.
    The primary potential acoustic impacts to marine mammal habitat are 
associated with elevated sound levels produced by vibratory and impact 
pile driving and removal in the area. However, other potential impacts 
to the surrounding habitat from physical disturbance are also possible.
    The proposed dredging activities were designed to remove impacted 
sediments (i.e., sediments with metals and/or polycyclic aromatic 
hydrocarbon (PAH) concentrations exceeding sediment cleanup objectives. 
The volume of potentially contaminated material subject to dredging and 
treatment or disposal in an approved hazardous waste facility is 
estimated to be 17,300 cubic yards. The dredging activities are 
predicted to have a positive impact on the habitat, and any negative 
short term impacts (discussed below) are inconsequential in comparison 
to the

[[Page 26644]]

overall benefit the environment will receive from these actions.
    Sediments within the proposed dredge footprint at the Skagway 
Harbor have been recently sampled and tested (Anchor QEA 2014). 
Sediment chemistry data show levels of current sediment contamination 
that may cause low, chronic, long term ecological effects to benthic 
habitats, but would not likely cause acute, toxic effects within the 
water column. The dredge prism of potentially contaminated sediment 
occupies approximately 41,000 square feet (0.004 square kilometers), 
adjacent to the Ore Dock. Physical resuspension of sediments would 
occur during dredging and would produce localized impacts to water 
quality in the form of elevated turbidity plumes that would last from a 
few minutes to several hours. Associated contaminants are expected to 
be tightly bound to the sediment matrix. Because of the relatively 
small dredge prism, these plumes would be limited to the immediate 
vicinity of the Ore Dock and this portion of Skagway Harbor. There is 
the potential for pinnipeds to be exposed to increased turbidity during 
dredge operations within Skagway Harbor. However, exposure to 
resuspended contaminants is expected to be low since sediments would 
not be ingested and contaminants would be tightly bound to them. Best 
management practices will be instituted to limit exposure pathways in 
areas where dredge materials are being handled. Given the relatively 
small dredge footprint, which limits the size of the dredge plume; the 
turbidity will be limited by efforts taken to limit/prevent exposure 
through BMPs; the plume will be temporary and will not have a direct 
exposure mechanism to marine mammals; and activities will occur during 
the winter period when fewer pinnipeds have been observed in the area, 
effects on marine mammals are considered negligible.

Construction Effects on Potential Prey

    Construction activities would produce continuous (i.e., vibratory 
pile driving) sounds 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 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.
    Construction activities, in the form of increased turbidity, have 
the potential to adversely affect forage fish and juvenile salmonid 
outmigratory routes in the project area. Both herring and salmon form a 
significant prey base for Steller sea lions, and herring is a primary 
prey of humpback whales. Increased turbidity is expected to occur in 
the immediate vicinity (on the order of 10 feet or less) of 
construction activities. However, suspended sediments and particulates 
are expected to dissipate quickly within a single tidal cycle. Given 
the limited area affected and high tidal dilution rates any effects on 
forage fish and salmon are expected to be minor or negligible. In 
addition, best management practices will be in effect, which will limit 
the extent of turbidity to the immediate project area. Finally, 
exposure to these contaminants from dredging is not expected to be 
different from the current exposure; fish and marine mammals in the 
Taiya Inlet/Lynn Canal region are routinely exposed to substantial 
levels of suspended sediment from glacial sources.

Construction Effects on Potential Foraging Habitat

    Pile installation may temporarily increase turbidity resulting from 
suspended sediments. Any increases would be temporary, localized, and 
minimal. MOS must comply with state water quality standards during 
these operations by limiting the extent of turbidity to the immediate 
project area. In general, turbidity associated with pile installation 
is localized to about a 25-foot radius around the pile (Everitt et al. 
1980). Cetaceans are not expected to be close enough to the project 
pile driving areas to experience effects of turbidity, and any 
pinnipeds will be transiting the area and could avoid localized areas 
of turbidity. Therefore, the impact from increased turbidity levels is 
expected to be discountable to marine mammals. Furthermore, pile 
driving and removal at the project site will not obstruct movements or 
migration of marine mammals.
    Noise measurements of dredging activities are rare in the 
literature, but dredging is considered to be a low-impact activity for 
marine mammals, producing non-pulsed sound and being substantially 
quieter in terms of acoustic energy output than sources such as seismic 
airguns and impact pile driving. Noise produced by dredging operations 
has been compared to that produced by a commercial vessel travelling at 
modest speed (Robinson et al., 2011). Further discussion of dredging 
sound production may be found in the literature (e.g., Richardson et 
al., 1995, Nedwell et al., 2008, Parvin et al., 2008, Ainslie et al., 
2009). Generally, the effects of dredging on marine mammals are not 
expected to rise to the level of a take. However, one study found peak 
sound pressure levels from clamshell dredging in Cook Inlet measured 
124 decibels (re 1 [mu]Pa) at the 150 meter isopleth with the peak 
sound levels associated with the dredger striking the hard ocean floor 
(Dickerson et al. 2001). Therefore, to further reduce potential 
acoustic impacts to endangered humpback whales and Steller sea lions, 
there will be a 200 meter dredging shutdown zone for ESA-listed 
species.

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.
    Measurements from similar pile driving events were coupled with 
practical spreading loss to estimate zones of influence (ZOI; see 
Estimated Take by Incidental Harassment); these values were used to 
develop mitigation measures for pile driving and removal activities at 
SOT. The ZOIs effectively represent the mitigation zone that would be 
established around each pile to provide estimates of the areas within 
which Level B, and potential Level A, harassment might occur. In 
addition to the specific measures described later in this section, MOS 
would conduct briefings between construction supervisors and crews, 
marine mammal monitoring team, and other staff prior to the start of 
all pile driving activity, and

[[Page 26645]]

when new personnel join the work, in order to explain responsibilities, 
communication procedures, marine mammal monitoring protocol, and 
operational procedures.
    For the proposed project, MOS worked with NMFS and proposed the 
following mitigation measures to minimize the potential impacts to 
marine mammals in the project vicinity. The primary purposes of these 
mitigation measures are to minimize sound levels from the activities, 
and to monitor marine mammals within designated zones of influence 
corresponding to NMFS' current Level A and B harassment thresholds 
which are depicted in Table 4 found later in the Estimated Take by 
Incidental Harassment section.

Monitoring and Shutdown for Pile Driving

    The following measures, developed by MOS and NMFS, would apply to 
the MOS's mitigation through shutdown and disturbance zones:
    Shutdown Zone--For all pile driving activities, the MOS will 
establish a shutdown zone intended to contain the area in which SPLs 
equal or exceed the 180 dB rms acoustic injury criteria for cetaceans, 
and 190 dB rms for 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 5 below. A minimum shutdown zone of 
16 m will be established for the 190-dB zone, and 74 m for the 180 dB 
zone.
    A 200 meter shutdown zone will be in effect for ESA-listed species 
for potential acoustic disturbance caused by clamshell dredging. This 
activity has been recorded at 124 dB peak at the 150 meter isopleth 
(Dickerson et al 2001). Peak SPLs are generally a few dB higher than 
rms SPLs. In this instance, we do not know exactly what the difference 
would be, and while this activity may exceed marine mammal acoustic 
thresholds at its source, we do not expect this activity to rise above 
background noise in this industrial area (see Description of Sound 
Sources section for more information), and therefore do not consider 
take for this activity. Acoustic impacts from clamshell dredging will 
not be considered further in this document.
    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 incidents 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 5. Given the size of the disturbance zone for 
vibratory pile driving, 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 within 
the SOT) would be observed.
    In order to document observed incidents 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 
or removed, 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.
    Monitoring Protocols--Monitoring would be conducted before, during, 
and after pile driving and removal activities. In addition, observers 
shall record all incidents of marine mammal occurrence, regardless of 
distance from activity, and shall document any behavioral reactions in 
concert with distance from piles being driven or removed. 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 
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 thirty 
minutes. Please see Appendix A of the application for details on the 
marine mammal monitoring plan developed by the MOS with NMFS' 
cooperation.
    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. Qualified observers 
are trained biologists, with the following 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) Advanced education in biological science or related field 
(undergraduate degree or higher required);
    (c) Experience and ability to conduct field observations and 
collect data according to assigned protocols (this may include academic 
experience);
    (d) Experience or training in the field identification of marine 
mammals, including the identification of behaviors;
    (e) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    (f) 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
    (g) 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.

[[Page 26646]]

    (2) 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.
    (3) 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 the animal. Monitoring will be conducted 
throughout the time required to drive a pile.

Ramp Up or 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.'' The project will utilize soft start techniques 
for all vibratory and impact pile driving. The MOS will initiate sound 
from vibratory hammers for fifteen seconds at reduced energy followed 
by a 1-minute waiting period, with the procedure repeated two 
additional times. For impact driving, we require an initial set of 
three strikes from the impact hammer at reduced energy, followed by a 
1-minute waiting period, then two subsequent three strike sets. Soft 
start will be required at the beginning of each day's pile driving work 
and at any time following a cessation of pile driving of thirty minutes 
or longer.
    If a marine mammal is present within the Level A harassment zone, 
ramping up will be delayed until the animal(s) leaves the Level A 
harassment zone. Activity will begin only after the Marine Mammal 
Observer (MMO) has determined, through sighting, that the animal(s) has 
moved outside the Level A harassment zone, or if 15 minutes have passed 
without resighting the animals.
    In addition to the measures described later in this section, the 
MOS would employ the following standard mitigation measures:
    (a) Conduct briefings between construction supervisors and crews, 
marine mammal monitoring team, and other 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.
    (b) For in-water heavy machinery work other than pile driving 
(using, 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 m, operations shall cease and vessels shall 
reduce speed to the minimum level required to maintain steerage and 
safe working conditions.
    Time Restrictions--In-water work would occur only during daylight 
hours, when visual monitoring of marine mammals can be conducted. To 
minimize impacts to hooligan, Pacific herring, and capelin, during 
their spawning and migration period, all in-water pile extraction and 
installation will be suspended during this time (April 1 through May 
31).
    Sound attenuation devices--Sound levels can be greatly reduced 
during impact pile driving using sound attenuation devices. There are 
several types of sound attenuation devices including bubble curtains, 
cofferdams, and isolation casings (also called temporary noise 
attenuation piles [TNAP]), and cushion blocks. The MOS proposes to use 
bubble curtains and pile caps. Pile caps include a mat that rests on 
the piles that have been driven into soft or unstable ground to provide 
a suitable stable foundation, thus reducing sound levels. Bubble 
curtains create a column of air bubbles rising around a pile from the 
substrate to the water surface. The air bubbles absorb and scatter 
sound waves emanating from the pile, thereby reducing the sound energy.
    Bubble curtains may be confined or unconfined. An unconfined bubble 
curtain may consist of a ring seated on the substrate and emitting air 
bubbles from the bottom. An unconfined bubble curtain may also consist 
of a stacked system, that is, a series of multiple rings placed at the 
bottom and at various elevations around the pile. Stacked systems may 
be more effective than non-stacked systems in areas with high current 
and deep water (Oestman et al., 2009).
    A confined bubble curtain contains the air bubbles within a 
flexible or rigid sleeve made from plastic, cloth, or pipe. Confined 
bubble curtains generally offer higher attenuation levels than 
unconfined curtains because they may physically block sound waves and 
they prevent air bubbles from migrating away from the pile. For this 
reason, the confined bubble curtain is commonly used in areas with high 
current velocity (Oestman et al., 2009).
    Both environmental conditions and the characteristics of the sound 
attenuation device may influence the effectiveness of the device. 
According to Oestman et al. (2009):
     In general, confined bubble curtains attain better sound 
attenuation levels in areas of high current than unconfined bubble 
curtains. If an unconfined device is used, high current velocity may 
sweep bubbles away from the pile, resulting in reduced levels of sound 
attenuation.
     Softer substrates may allow for a better seal for the 
device, preventing leakage of air bubbles and escape of sound waves. 
This increases the effectiveness of the device. Softer substrates also 
provide additional attenuation of sound traveling through the 
substrate.
     Flat bottom topography provides a better seal, enhancing 
effectiveness of the sound attenuation device, whereas sloped or 
undulating terrain reduces or eliminates its effectiveness.
     Air bubbles must be close to the pile; otherwise, sound 
may propagate into the water, reducing the effectiveness of the device.
     Harder substrates may transmit ground-borne sound and 
propagate it into the water column.
    The literature presents a wide array of observed attenuation 
results for bubble curtains (e.g., Oestman et al., 2009; Coleman, 
2011;). The variability in attenuation levels is due to variation in 
design, as well as differences in site conditions and difficulty in 
properly installing and operating in-water attenuation devices. As a 
general rule, reductions of greater than 10 dB cannot be reliably 
predicted. For 36-in piles the average rms reduction with use of the 
bubble curtain was nine dB, where the averages of all bubble-on and 
bubble-off data were compared. For 48-in piles, the average SPL 
reduction with use of a

[[Page 26647]]

bubble curtain was seven dB for average rms values.
    To avoid loss of attenuation from design and implementation errors, 
the MOS has required specific bubble curtain design specifications, 
including testing requirements for air pressure and flow prior to 
initial impact hammer use, and a requirement for placement on the 
substrate. Bubble curtains shall be used during all impact pile 
driving. The device will distribute air bubbles around 100 percent of 
the piling perimeter for the full depth of the water column, and the 
lowest bubble ring shall be in contact with the mudline for the full 
circumference of the ring. We considered six dB as potentially the best 
estimate of average SPL (rms) reduction, assuming appropriate 
deployment and no problems with the equipment. Therefore, a six dB 
reduction was used in the MOS's analysis of pile driving noise in the 
environmental analyses.

Timing Restrictions

    In the SOT, designated timing restrictions exist for pile driving 
activities to avoid in-water work during the hooligan run in the spring 
(April and May) when marine mammals arrive in huge numbers to feed. The 
in-water work window is between July and October, to avoid this 
spawning run. All in-water construction activities will occur during 
daylight hours (sunrise to sunset)

Contaminant Exposure Mitigation

    To minimize the potential for marine mammals to be exposed to 
harmful or toxic contaminants in the sediment during dredging 
operations, mitigation measures will be employed. These measures 
include a partial height silt curtain and contamination sequencing. The 
objective when using silt curtains is to create a physical barrier 
around the dredge equipment by protecting against the spread of 
suspended sediment that is generated during dredging operations in the 
portion of the water column in which the silt curtain extends. Silt 
curtains can be effective tools to minimize or reduce potential water 
quality impacts during dredging, when used properly and in the right 
site conditions. The silt curtain will be constructed of flexible, 
reinforced, thermoplastic material with flotation material in the upper 
hem and ballast material in the lower hem. The curtain will be placed 
in the water surrounding the dredging operation. The specifications 
will require that the Contractor maintain the silt curtain(s) around 
either the point of dredging or the dredging area (and potentially 
other in-water construction areas) at the contractor's discretion, in 
order to reduce the potential for water quality impacts and the 
transport of suspended solids beyond the project dredging boundaries.
    Because they are mostly impermeable, silt curtains are easily 
affected by tides and currents and their effectiveness can be adversely 
impacted by high current velocities, moderate to large wave conditions, 
or large tidal variation. The required height of the silt curtain will 
be determined during subsequent design to determine a height that 
balances environmental protection and the efficiency to maintain the 
silt curtain in place during dredging based on tidal and current 
velocities in the harbor. The effectiveness of the silt curtain will be 
monitored during construction and changes may be implemented based on 
the results of monitoring to either enhance the protection of the silt 
curtain or otherwise make modifications to the silt curtain 
configuration to provide for more effective dredge operations while 
still meeting water quality requirements.
    Contamination sequencing involves prioritizing the removal of the 
most impacted areas (i.e., the area with the highest observed 
concentrations of contaminants of concern) before the surrounding 
areas. Ultimately, the necessary phasing and sequencing of the overall 
project (e.g., dock demolition to facilitate remedial dredging) must be 
taken into consideration along with the safety of the dredging 
contractor.

Mitigation Conclusions

    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of affecting the least 
practicable impact on the affected marine mammal species and stocks and 
their habitat. Our evaluation of potential measures included 
consideration of the following factors in relation to one another: (1) 
The manner in which, and the degree to which, the successful 
implementation of the measure is expected to minimize adverse impacts 
to marine mammals; (2) the proven or likely efficacy of the specific 
measure to minimize adverse impacts as planned; and (3) the 
practicability of the measure for applicant implementation,
    Any mitigation measure(s) prescribed by NMFS 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 numbers of marine mammals (total number or 
number at biologically important time or location) exposed to received 
levels of pile driving, or other activities expected to result in the 
take of marine mammals (this goal may contribute to 1, above, or to 
reducing harassment takes only).
    (3) A reduction in the number of times (total number or number at 
biologically important time or location) individuals would be exposed 
to stimuli expected to result in incidental take of marine mammals 
(this goal may contribute to 1, above, or to reducing harassment takes 
only).
    (4) A reduction in the intensity of exposures (either total number 
or number at biologically important time or location to stimuli 
expected to result in incidental take (this goal may contribute to 1, 
above, or to reducing the severity of harassment takes only).
    (5) Avoidance or minimization of adverse effects to marine mammal 
habitat, paying particular attention to the prey base, activities that 
block or limit passage to or from biologically important areas, 
permanent destruction of habitat, or temporary destruction/disturbance 
of habitat during a biologically important time.
    (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 applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on marine mammals species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.
    Proposed measures to ensure availability of such species or stock 
for taking for certain subsistence uses are discussed later in this 
document (see Impact on Availability of Affected Species or Stock for 
Taking for Subsistence Uses section).

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

[[Page 26648]]

regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
incidental take 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.
    Any monitoring requirement we prescribe should improve our 
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 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 responses to acute stressors, or impacts of 
chronic exposures (behavioral or physiological).
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of an individual; or (2) Population, 
species, or stock.
     Effects on marine mammal habitat and resultant impacts to 
marine mammals.
     Mitigation and monitoring effectiveness.
    The MOS submitted a marine mammal monitoring plan as part of the 
IHA application for this project, which can be found at 
www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. The plan may 
be modified or supplemented based on comments or new information 
received from the public during the public comment period.

Visual Marine Mammal Observation

    The MOS 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 observers will be trained 
in marine mammal identification and behaviors and are required to have 
no other construction-related tasks while conducting monitoring. The 
MOS will monitor the shutdown zone and disturbance zone before, during, 
and after pile driving, with observers located at the best practicable 
vantage points. The Marine Mammal Observers (MMOs) and MOS authorities 
will meet to determine the most appropriate observation platform(s) for 
monitoring during pile installation and extraction.
    Based on our requirements, the MOS would implement the following 
procedures for pile driving:
     Individuals meeting the minimum qualifications identified 
in the applicant's monitoring plan (Appendix A of the application) 
would monitor Level A and Level B harassment zones during pile driving 
and extraction activities.
     The area within the Level B harassment threshold for 
impact driving will be monitored by appropriately stationed MMOs. Any 
marine mammal documented within the Level B harassment zone during 
impact driving would constitute a Level B take (harassment), and will 
be recorded and reported as such.
     During impact and vibratory pile driving, a shutdown zone 
will be established to include all areas where the underwater SPLs are 
anticipated to equal or exceed the Level A (injury) criteria for marine 
mammals (180 dB isopleth for cetaceans; 190 dB isopleth for pinnipeds). 
Pile installation will not commence or will be suspended temporarily if 
any marine mammals are observed within or approaching the area.
     The individuals will scan the waters within each 
monitoring zone activity using binoculars, spotting scopes, and visual 
observation.
     Use a hand-held or boat-mounted GPS device or rangefinder 
to verify the required monitoring distance from the project site.
     If poor environmental conditions restricts the observers' 
ability to make observations within the marine mammal shutdown zone 
(e.g. excessive wind or fog, high beaufort state), pile installation 
will cease. Pile driving will not be initiated until the entire 
shutdown zone is visible.
     Conduct pile driving and extraction activities only during 
daylight hours from sunrise to sunset when it is possible to visually 
monitor marine mammals.
     The waters will be scanned 15 minutes prior to commencing 
pile driving at the beginning of each day, and prior to commencing pile 
driving after any stoppage of 30 minutes or greater. If marine mammals 
enter or are observed within the designated marine mammal shutdown zone 
during or 15 minutes prior to pile driving, the monitors will notify 
the on-site construction manager to not begin until the animal has 
moved outside the designated radius.
     The waters will continue to be scanned for at least 30 
minutes after pile driving has completed each day, and after each 
stoppage of 30 minutes or greater.

Data Collection

    We require that observers use approved data forms. Among other 
pieces of information, the MOS 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 MOS will attempt to 
distinguish between the number of individual animals taken and the 
number of incidents 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 distance from 
pile driving activity;
     Distance from pile driving 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 sixty 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 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 thirty days following resolution of 
comments on the draft report.

[[Page 26649]]

    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as serious injury or mortality (e.g., ship-strike, 
gear interaction, and/or entanglement), the MOS would immediately cease 
the specified activities and immediately report the incident to the 
Chief of the Permits and Conservation Division, Office of Protected 
Resources, NMFS, and the Alaska Stranding Coordinator. The report would 
include the following information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Name and type of vessel involved;
     Vessel's speed during and leading up to the incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     Water depth;
     Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with the MOS to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. The MOS would not be able 
to resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that the MOS discovers an injured or dead marine 
mammal, and the lead MMO determines that the cause of the injury or 
death is unknown and the death is relatively recent (i.e., in less than 
a moderate state of decomposition as described in the next paragraph), 
the MOS would immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the Alaska Stranding Coordinator.
    The report would include the same information identified in the 
paragraph above. Activities would be able to continue while NMFS 
reviews the circumstances of the incident. NMFS would work with the MOS 
to determine whether modifications in the activities are appropriate.
    In the event that the MOS discovers an injured or dead marine 
mammal, and the lead MMO determines that the injury or death is not 
associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), the MOS would report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the NMFS West Coast Stranding Hotline 
and/or by email to the Alaska Stranding Coordinator, within 24 hours of 
the discovery. The MOS would provide photographs or video footage (if 
available) or other documentation of the stranded animal sighting to 
NMFS and the Marine Mammal Stranding Network.

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, 
section 3(18) of the MMPA defines ``harassment'' as: ``. . . any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild [Level A harassment]; 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering [Level B harassment].''
    All anticipated takes would be by Level B harassment resulting from 
vibratory pile driving and removal. Level B harassment may result in 
temporary changes in behavior. Note that Level A harassment and lethal 
takes are not expected due to the proposed mitigation and monitoring 
measures that are expected to minimize the possibility of such take.
    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). Given the many uncertainties in predicting the 
quantity and types of impacts of sound on marine mammals, it is common 
practice to estimate how many animals are likely to be present within a 
particular distance of a given activity, or exposed to a particular 
level of sound. In practice, depending on the amount of information 
available to characterize daily and seasonal movement and distribution 
of affected marine mammals, it can be difficult to distinguish between 
the number of individuals harassed and the instances of harassment and, 
when duration of the activity is considered, it can result in a take 
estimate that overestimates the number of individuals harassed. In 
particular, for stationary activities, it is more likely that some 
smaller number of individuals may accrue a number of incidences of 
harassment per individual than for each incidence to accrue to a new 
individual, especially if those individuals display some degree of 
residency or site fidelity and the impetus to use the site (e.g., 
because of foraging opportunities) is stronger than the deterrence 
presented by the harassing activity.
    Upland work can generate airborne sound and create visual 
disturbance that could potentially result in disturbance to marine 
mammals (specifically, pinnipeds) that are hauled out or at the water's 
surface with heads above the water. However, because any haul-outs in 
close proximity to the SOT would be subsumed in the disturbance zone, 
incidents of incidental take resulting from airborne sound or visual 
disturbance would already be included in those counts.
    In order to estimate the potential incidents of take that may occur 
incidental to the specified activity, we must first estimate the extent 
of the sound field that may be produced by the activity and then 
consider in combination with information about marine mammal density or 
abundance in the project area. We first provide information on 
applicable sound thresholds for determining effects to marine mammals 
before describing the information used in estimating the sound fields, 
the available marine mammal density or abundance information, and the 
method of estimating potential incidences of take.

Sound Thresholds

    We use the following generic sound exposure thresholds to determine 
when an activity that produces sound might result in impacts to a 
marine mammal such that a take by harassment might occur. These 
thresholds (Table 4) are used to estimate when harassment may occur 
(i.e., when an animal is exposed to levels equal to or exceeding the 
relevant criterion) in specific contexts; however, useful contextual 
information that may inform our assessment of effects is typically 
lacking and we consider these thresholds as step functions. NMFS is 
working to revise

[[Page 26650]]

these acoustic guidelines; for more information on that process, please 
visit www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

               Table 4--Current Acoustic Exposure Criteria
------------------------------------------------------------------------
          Criterion           Criterion definition       Threshold *
------------------------------------------------------------------------
Level A harassment            PTS (injury)          190 dB RMS for
 (underwater).                 conservatively        pinnipeds, 180 dB
                               based on TTS **.      RMS for cetaceans.
Level B harassment            Behavioral            160 dB RMS
 (underwater).                 disruption.           (impulsive source),
                                                     120 dB RMS
                                                     (continuous
                                                     source).
Level B harassment            Behavioral            90 dB (harbor
 (airborne).                   disruption.           seals), 100dB
                                                     (other pinnipeds)
                                                     (unweighted).
------------------------------------------------------------------------
* All decibel levels referenced to 1 micropascal (re: 1 [mu]Pa). Note
  all thresholds are based off root mean square (RMS) levels.
** PTS = Permanent Threshold Shift; TTS = Temporary Threshold Shift.

Distance to Sound Thresholds

    The sound field in the project area is the existing ambient noise 
plus additional construction noise from the proposed project. The 
primary components of the project expected to affect marine mammals is 
the sound generated by impact pile driving, vibratory pile driving, and 
vibratory pile removal. Dredging and direct pull and clamshell removal 
of old timber piles do not produce noise levels expected to result in 
take of marine mammals. This activity has been recorded at 124 dB peak 
at the 150 meter isopleth (Dickerson et al 2001). While this activity 
may exceed marine mammal acoustic thresholds at its source, we do not 
expect this activity to rise above background noise in this industrial 
area, and therefore do not consider take for this activity. Depending 
on conditions, removal of timber piles may require vibratory hammer 
removal. Impact hammering typically generates the loudest noise 
associated with pile driving.
    The project includes vibratory removal of steel piles and creosote-
treated piles, summarized in Table 1; and vibratory installation of 24-
, 36-, 48-, and 60-inch diameter steel pipe piles, summarized in Table 
2. The Washington State Department of Transportation (WSDOT) and 
California Department of Transportation have compiled acoustic 
monitoring data for various pile-driving projects within their 
respective states (WSDOT unpublished; ICF Jones & Stokes and 
Illingworth and Rodkin 2009, updated in 2012). Upon review of these 
datasets, it was determined that driving moderate-sized steel piles 
with a vibratory pile driver will generate sound pressure levels (SPLs) 
of 170 dB RMS (ICF Jones & Stokes and Illingworth and Rodkin 2009, 
updated in 2012). Noise levels are on the order of 150 dB rms from pile 
removal activities.
    Underwater Sound Propagation Formula--Pile driving 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 * log 10 (R 1/R 2),

Where:

TL = transmission loss in dB
R 1 = the distance of the modeled SPL from the driven pile, 
and
R 2 = the distance from the driven pile of the initial 
measurement

    A practical spreading value of fifteen is often used under 
conditions, such as at the Skagway ore terminal, 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.
    Distances to the harassment isopleths vary by pile type and size, 
and by pile extraction/driving tool. These distances are summarized in 
Table 5. Note that the actual area ensonified by pile driving or 
removal activities is significantly constrained by local topography 
relative to the total threshold radius. The actual ensonified area was 
determined using a straight line-of-sight projection from the 
anticipated pile driving locations. Distances shown in Table 5 are 
estimated for free-field conditions, but areas are calculated per the 
actual conditions of the action area. See Figures 2-5 of the MOS's 
application for a depiction of areas in which each underwater sound 
threshold is predicted to occur at the project area due to pile driving 
or removal.

                                 Table 5--Distances to Relevant Underwater Sound Thresholds and Areas of Ensonification
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Distance to criterion (m)
                                                     ----------------------------------------------------------------
              Pile type               Pile size (in)                      Level A         Level A                                 Area (km2)
                                                       Level B (160   cetaceans (180  pinnipeds (190    Continuous
                                                            dB)             dB)             dB)           (120dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Impact..............................              24           1,848              86              18  ..............  3.93, 0.072, 0.031.*
                                                  36           1,585              74              16  ..............  3.00, 0.064, 0.029.*
                                                  48           2,154             100              22  ..............  4.96, 0.082, 0.033.*
Vibratory...........................              60  ..............  ..............  ..............         100,000  21.
Vibratory removal...................              12  ..............  ..............  ..............           1,600  3.05.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Values are for 160 dB, 180 dB, and 190 dB, respectively.


[[Page 26651]]

Marine Mammal Densities

    Density data are only available for harbor seals for this area of 
Alaska. Potential exposures to impact and vibratory pile driving noise 
for each threshold for all other marine mammals were estimated using 
published reports of group sizes and population estimates, and 
anecdotal observational reports from local commercial entities. It is 
not currently possible to identify all observed individuals to stock. 
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 largest ZOI. The largest 
underwater disturbance ZOI would be produced by vibratory driving steel 
piles. The ZOIs for each threshold are not spherical and are truncated 
by land masses on either side of the channel which would dissipate 
sound pressure waves.
     Exposures were based on estimated work days. Numbers of 
days were based on an average production rate of 73 days of vibratory 
and impact driving and 39 days of pile removal. Note that impact 
driving is likely to occur only on days when vibratory driving occurs.
     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-h period; 
and,
     Exposures to sound levels at or above the relevant 
thresholds equate to take, as defined by the MMPA.
    The estimation of marine mammal takes typically uses the following 
calculation:
Level B exposure estimate = N (number of animals) in the ensonified 
area * Number of days of noise generating activities

    There are a number of reasons why estimates of potential incidents 
of take may be overestimates of the number of individuals taken, 
assuming that available abundance estimates and estimated ZOI areas are 
accurate. We assume, in the absence of information supporting a more 
refined conclusion, that the output of the calculation represents the 
number of individuals that may be taken by the specified activity. In 
fact, 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 instances of take that may occur to a small number of 
individuals, with a notably smaller number of animals being exposed 
more than once per individual. While pile driving 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. 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, especially if each 
take is considered a separate individual animal, and especially for 
pinnipeds. See Table 6 for total estimated incidents of take.

                              Table 6--Calculations for Incidental Take Estimation
----------------------------------------------------------------------------------------------------------------
                                                  N (animals) in                     Proposed authorized takes
                     Species                      the ensonified  Number of days -------------------------------
                                                       area         of activity       Level A         Level B
----------------------------------------------------------------------------------------------------------------
Harbor Seal.....................................              44              74               0           2,272
Steller sea lion................................              32              74               0           1,184
Humpback whale..................................               2              42               0              84
Killer whale....................................              15               4               0              60
Harbor porpoise.................................               2              84               0             168
Dall's porpoise.................................               3              15               0              45
Minke whale.....................................               0               0               0               0
                                                 ---------------------------------------------------------------
    Total exposures.............................  ..............  ..............               0           3,813
----------------------------------------------------------------------------------------------------------------

Description of Marine Mammals in the Area of the Specified Activity

Harbor Seals
    There are no documented long-term haulout sites for harbor seals in 
Taiya Inlet; however, seasonal haulouts are present within five miles 
of the project area at Seal Cove and at the mouth of the Taiya River. 
During the spring run of hooligan in April and May, 20 to over 100 
individual animals have been observed in these areas, with animals 
within inner Taiya Inlet actively feeding. After the spawning run, much 
lower numbers of harbor seals are present. Local observers have found 
that very few, if any; harbors seals are present during the winter (R. 
Ford and K. Gross, personal communications). Harbor seals within the 
Lynn Canal/Stephens Passage stock have maintained a steady to slightly 
declining population over the past five years. The latest stock 
assessment analysis indicates that there is a 71 percent probability 
that the stock has declined by 1.8 percent over this period (Muto and 
Angliss 2015). Using seal stock assessment data from within the Lynn 
Canal/Stephens Passage stock, the calculated density of this stock is 
1.7 animals per square kilometer (total population divided by total 
area). This density was applied to the area within the behavioral 
impact zone for vibratory driving (21 square kilometers, which includes 
most of Taiya Inlet) for a total of 36 animals in the whole of Taiya 
Inlet. These animals are mostly on haulouts in the vicinity of Seal 
Cove, swimming in areas near the waterfront, and hauled out at the 
mouth of the Taiya River. Proposed pile driving will occur in March, 
and in July through October, avoiding the hooligan spawning run and the 
period of maximum local abundance of harbor seals.
    Because harbor seal numbers decrease after the spring hooligan 
spawning run, we estimate that the number of local animals within the 
behavioral zones is estimated to be eight animals (one half of the mean 
range within the lower inlet). This estimate is based on the 
conservative assumption that about half of the animals hauled out at 
Seal Cove and the Taiya River mouth may be transiting through the 
behavioral zone for vibratory driving at any given time during the 
summer (14 days), for a total of 112 takes. The haulouts themselves are 
outside of the behavioral impact zones, approximately five miles from 
the project area. No exposure to the injury zone is expected because of 
the mitigation measures designed to prevent Level A harassment. It is 
expected that the marine mammal monitoring

[[Page 26652]]

program will significantly prevent injury take in this zone. Based on 
calculated density estimates mentioned above, all 36 animals will be 
exposed to the continuous noise behavioral zone, which includes most of 
Taiya Inlet for all days when pile driving activities are expected to 
occur (60 days) for a total of 2,160 takes during this time period. 
Total requested harbor seal takes is 2,272.
Steller Sea Lion
    There are several long-term Steller sea lion haulouts in Lynn Canal 
but none occur in Taiya Inlet. The nearest long-term Steller sea lion 
haulout is located at Gran Point, in the vicinity of Haines 
approximately 20 miles south of Skagway. Other year-round haulouts in 
Lynn Canal are present at Met Point, Benjamin Island, and Little 
Island, closer to Juneau (Fritz et al. 2015). A seasonal haulout site 
is located on Taiya Point rocks at the southern tip of Taiya Inlet. 
Estimates of 25 to 40 animals use this haulout for about three weeks 
during the hooligan run, during which they frequent the inlet (K. 
Gross, personal communication). However, most animals leave the inlet 
shortly after the hooligan run and are scarce after about the first 
week in June. Sea lions are rarely observed in the inlet during the 
winter. This is consistent with the National Marine Mammal Laboratory 
database (Fritz et al., 2015), which has identified the largest number 
of Lynn Canal sea lions during the fall and winter months at Benjamin 
Island in the lower reaches of the canal.
    Taiya Point Rocks are located approximately 12 miles south of 
Skagway and 1.3 miles outside of the continuous noise vibratory 
behavioral impact zone. Given that sea lion presence in Taiya Inlet 
occurs during the hooligan run, during which no pile driving will 
occur, and the nearest haulout site is outside of the behavioral impact 
zone, it is expected that Steller sea lion exposure to pile driving 
will be low. This is similar to observations from local observers, who 
have reported one to three sea lions in Taiya Inlet outside of the 
hooligan spawning run (K. Gross, personal communication). Sea lions 
have been observed in greater numbers in nearby Lutak Inlet in the fall 
during salmon runs, and at the Gran Point haulout near Haines. These 
observations and data suggest that it is reasonable to expect more sea 
lions to travel into Taiya Inlet (J. Womble, personal communication). 
There have been no observations of Steller sea lions in Taiya Inlet 
during the winter. Because Steller sea lions are sparse at times 
outside of the hooligan spawning run, but a portion of the hauled out 
seals may enter Taiya inlet during the salmon runs, we estimated that 
16 Steller sea lions (half of the mean found on Taiya Rocks during the 
hooligan run) will be present within Taiya Inlet during any given time 
while pile driving and pile removal operations are occurring in the 
summer and fall (60 and 14 days, respectively), for a total of 1,184 
total takes for Steller sea lions. Exposure to pile-driving and removal 
activities during the winter is not expected to occur. No Steller sea 
lions are expected to be exposed to the small injury zone near the 
facility. If any do appear, the marine mammal monitoring program would 
effectively prevent take.
Harbor Porpoises
    Harbor porpoise primarily frequent coastal waters, and in the Gulf 
of Alaska and Southeast Alaska, they occur most frequently in waters 
less than 100 meters (Dahlheim et al. 2009). Within the inland waters 
of Southeast Alaska, the harbor porpoise distribution is clumped, with 
greatest densities observed in the Glacier Bay/Icy Strait region, and 
near Zarembo and Wrangell Islands and the adjacent waters of Sumner 
Strait (Allen and Angliss 2014). Dedicated research studies of harbor 
porpoise in this area only occur as far north in Lynn Canal as Haines 
during the summer (Dahlheim et al., 2009; 2015); approximately 16 miles 
south of SOT. Group sizes were on average, between 1.37-1.59 animals 
(less than 2) (Dahlheim et al., 2009; 2015). In Lynn Canal, 
observations were less frequent, primarily in lower Lynn Canal from 
Chatham Strait to Juneau. The species has been observed as far north as 
Haines during the summer (Dahlheim et al., 2009, Dalheim et al., 2015). 
Encounters of small groups of two or three animals have been reported 
by local vessel charters from spring through fall in Taiya Inlet. 
Observations have been frequent, but not on a daily basis. The mean 
group size of harbor porpoise in Southeast Alaska is estimated at two 
individuals (Dahlheim et al. 2009). For the purposes of this analysis 
it is estimated that two harbor porpoises will be present in Taiya 
Inlet, but because observations do not occur daily, we estimate their 
presence within the inlet on 75 percent of days during the pile driving 
period (84 days) for a total of 168 take exposures. Exposure to the 
behavioral disturbance zone from impact pile driving or pile removal is 
not likely to occur, because the species has rarely been observed in 
areas close to the waterfront.
Dall's Porpoise
    Dall's porpoise are widely distributed across the entire North 
Pacific Ocean. Throughout most of the eastern North Pacific they are 
present during all months of the year, although there may be seasonal 
onshore-offshore movements along the west coast of the continental 
United States and winter movements of populations out of Prince William 
Sound and areas in the Gulf of Alaska and Bering Sea (Allen and Angliss 
2014).
    Dahlheim et al. (2009) found Dall's porpoise throughout Southeast 
Alaska, with concentrations of animals consistently found in Lynn 
Canal, Stephens Passage, Icy Strait, upper Chatham Strait, Frederick 
Sound, and Clarence Strait. Local observers have observed only three to 
six Dall's porpoises in Taiya Inlet during the early spring and late 
fall. Observations have been occasional to sporadic, not occurring 
daily. The species has not been observed near the waterfront, and no 
animals have been observed during the winter (K. Gross, personal 
communication). This is consistent with Dahlheim et al. (2009), who 
have only documented this species in Lynn Canal as far north as Haines, 
Alaska, about 15 miles south of Skagway and 5 miles south of the 
continuous noise behavioral impact zone. The mean group size of Dall's 
porpoise in Southeast Alaska is estimated at three individuals 
(Dahlheim et al. 2009). For the purposes of this analysis, we estimate 
that three animals will be present in outer Taiya Inlet for the latter 
half of the summer pile-driving period. Since observations during the 
fall have been occasional, we also assume a presence in the inlet every 
other day, for a total of 15 days of exposure, and 45 total takes. 
Exposure to the behavioral disturbance zone from impact pile driving or 
pile removal is not likely to occur, because the species has rarely 
been observed in areas close to the waterfront.
Killer Whales
    Resident and transient killer whales have been documented in the 
middle to lower reaches of Lynn Canal, but not within the upper reaches 
or in Taiya Inlet (Dahlheim et al., 2009). Two resident pods identified 
as AF and AG pods were frequently encountered throughout Icy Strait, 
Lynn Canal, Stephens Passage, Frederick Sound and upper Chatham Strait 
(Dahlheim et al., 2009). The seasonality of resident killer whales 
could not be investigated statistically owing to low encounter rates. 
Mean group size of resident

[[Page 26653]]

whales did not vary significantly among seasons and ranged from 19 to 
33 individuals.
    Transient killer whales were found in all major waterways, 
including Lynn Canal in open-strait environments, near-shore waters, 
protected bays and inlets, and in ice-laden waters near tidewater 
glaciers (Dahlheim et al. 2009). Dahlheim et al. (2009) found that 
transient killer whale mean group size ranged from four to six 
individuals in Southeast Alaska. Transient killer whale numbers were 
highest in summer, with lower numbers observed in spring and fall. 
Although this stock's range includes southeast Alaska, it has only been 
documented as far north as Lynn Canal; therefore, while possible, 
occurrence north of Lynn Canal into Taiya Inlet is rare.
    Local observations indicate that resident pods occasionally enter 
Taiya Inlet, usually a group of 15 to 20 animals. These animals are 
typically observed only a few times a year (K. Gross, personal 
communication). In 2015 a resident pod was only observed in Taiya Inlet 
twice, remaining for one to four days per visit (K. Gross, personal 
communication). Based on these observations, we conservatively used the 
larger group size for all killer whale stocks (Northern residents), and 
the likelihood of stocks being present, to estimate a maximum of 60 
killer whale takes (e.g. for Northern residents, at most, 15 killer 
whales may enter the inlet on two occasions during the summer, 
remaining in the inlet for two days per visit. All other stocks would 
likely be smaller in group size, and not occur as frequently).
Humpback Whale
    Humpback whales are the most commonly observed baleen whale in the 
area and surrounding Southeast Alaska, particularly during spring and 
summer months. Humpback whales in Alaska, although not limited to these 
areas, return to specific feeding locations such as Frederick Sound, 
Chatham Strait, North Pass, Sitka Sound, Glacier Bay, Point Adolphus, 
and Prince William Sound, as well as other similar coastal areas (Wing 
and Krieger 1983). In Lynn Canal they have been observed in the spring 
and fall from Haines to Juneau. Scientific surveys have not documented 
the species within Taiya Inlet (Dahlheim et al., 2009). The humpback 
whale population in Southeast Alaska appears to be increasing with 
estimates of 547 animals in the mid-1980s (Angliss and Outlaw 2005) and 
961 animals in 2000 (Straley et al., 2002).
    Local observers have reported humpback whales in Taiya Inlet, 
sometimes fairly close to the Skagway waterfront. In 2015, only one 
whale was observed for a few weeks close to Skagway. On average, four 
to five individuals may occur near the town during the spring hooligan 
run, after which, only a few individuals are observed on and off 
through the summer (K. Gross, personal communication). No pile driving 
will occur during the spring hooligan run. For the purpose of this 
analysis, because humpback whale occurrence is rare and generally 
occurs in the spring when construction will not occur, it is estimated 
that two humpback whales may be present over two 3-week periods (42 
days) during the summer, for a total of 84 takes. Exposure to the 
behavioral disturbance zone from impact pile driving or pile removal is 
not likely to occur, because the species has rarely been observed in 
areas close to the waterfront.

Analysis and Preliminary Determinations

Negligible Impact

    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.'' 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 
Level B harassment 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 behavioral 
harassment, we consider 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 
the number and nature of estimated Level A harassment takes, the number 
of estimated mortalities, and effects on habitat.
    To avoid repetition, the discussion of our analyses applies 
generally to all the species listed in Table 3, given that the 
anticipated effects of this pile driving project on marine mammals are 
expected to be relatively similar in nature. Where there are species-
specific factors that have been considered, they are identified below.
    Pile extraction and pile driving, activities associated with the 
reconstruction of the SOT, 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 B harassment 
(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 are under way.
    The takes from Level B harassment will be due to potential 
behavioral disturbance and TTS. No mortality is anticipated given the 
nature of the activity 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 (see Proposed 
Mitigation section). Vibratory driving does not have significant 
potential to cause injury to marine mammals due to the relatively low 
source levels produced and the lack of potentially injurious source 
characteristics. Impact driving does have the potential to injure 
marine mammals; however; the marine mammal detection ability by trained 
observers is high under the environmental conditions described for the 
reconstruction of the SOT, which further enables the implementation of 
shutdowns to limit injury, serious injury, or mortality.
    The MOS's proposed activities are localized and of relatively short 
duration (maximum 73 days for pile driving activities; 39 days for pile 
removal, and a maximum of 40 days of dredging). The entire project area 
is limited to the SOT area and its immediate surroundings. These 
localized and short-term noise exposures may cause short-term 
behavioral modifications in harbor seals, Steller sea lions, killer 
whales, harbor porpoises, Dall's porpoises, and humpback whales. 
Moreover, the proposed mitigation and monitoring measures, including 
injury shutdowns, soft start techniques, and multiple MMOs monitoring 
the behavioral and injury zones for marine mammal presence, are 
expected to reduce the likelihood of injury and behavior exposures. 
Additionally, no important feeding and/or reproductive areas for marine 
mammals are known to be within the ensonification areas of the proposed 
action area during the construction time frame.
    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

[[Page 26654]]

the area of disturbance, thus temporarily impacting marine mammals' 
foraging opportunities in a limited portion of the foraging range; but, 
because of the short duration of the activities and the relatively 
small area of the habitat that may be affected, the impacts to marine 
mammal habitat are not expected to cause significant or long-term 
negative consequences.
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from other 
similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring) (e.g., Thorson and Reyff, 
2006; Lerma, 2014). Most likely, individuals will simply move away from 
the sound source and be temporarily displaced from the areas of pile 
driving, although even this reaction has been observed primarily only 
in association with impact pile driving. Repeated exposures of 
individuals to levels of sound that may cause Level B harassment are 
unlikely to result in permanent hearing impairment or to significantly 
disrupt foraging behavior due to the lack of quality foraging habitat 
near the ore terminal. 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.
    In summary, this negligible impact analysis is founded on the 
following factors: (1) The possibility of non-auditory injury, serious 
injury, or mortality may reasonably be considered discountable; (2) the 
anticipated instances of Level B harassment consist of, at worst, 
temporary modifications in behavior or potential TTS and; (3) the 
presumed efficacy of the proposed mitigation measures in reducing the 
effects of the specified activity to the level of least practicable 
impact. In combination, we believe that these factors, as well as the 
available body of evidence from other similar activities, demonstrate 
that the potential effects of the specified activity will have only 
short-term effects on individuals. The specified activity is not 
reasonably expected to and is not reasonably likely to adversely affect 
the marine mammal species or stocks through effects on annual rates of 
recruitment or survival and will therefore not result in population-
level impacts.
    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 MOS's reconstruction of the SOT will have a 
negligible impact on the affected marine mammal species or stocks.

Small Numbers Analysis

    Table 7 demonstrates the number of animals that could be exposed to 
received noise levels that could cause Level B behavioral harassment 
for the proposed work at the SOT project site. The numbers of animals 
authorized to be taken for all species would be considered small 
relative to the relevant stocks or populations even if each estimated 
taking occurred to a new individual--an extremely unlikely scenario. 
The total percent of the population for which take is requested is less 
than one percent for humpback whales (Central North Pacific stock), and 
less than 2.5 percent for affected stocks of Steller sea lions (eDPS 
and wDPS) and harbor porpoise (Southeast Alaska stock). The most recent 
abundance estimate (83,400) for the affected stock of Dall's porpoise 
(Alaska stock) is over 20 years old (Allen and Angliss 2012); 
therefore, the stock size is unknown for Dall's porpoise. The total 
percent of the population for which take is requested is therefore also 
unknown; however, the 45 total take requests is a small enough number 
that it would be considered a small percent of this stock, which we 
know is fairly large based on anecdotal information. For killer whales 
(Alaska stock, Northern resident stock, Gulf of Alaska stock, and West 
Coast transient stock) and harbor seals (Lynn Canal/Stephens Passage 
stock), the percentage of the stock for which take is requested is less 
than 25 percent for all affected stocks. For pinnipeds, especially 
harbor seals occurring in the vicinity of the SOT, there will almost 
certainly be some overlap in individuals present day-to-day, and these 
takes are likely to occur only within some small portion of the overall 
regional stock.
    The total authorized take for killer whales as compared to each 
potentially affected stock ranges from 2.7% to 24.7% of each 
population. In reality, it is highly unlikely that 60 individuals of 
any one killer whale stock will not be temporarily harassed. Instead, 
it is assumed that there will be a relatively short period of takes of 
a smaller number of the same individuals from any stock. We make this 
assumption because resident pods are known to occasionally frequent 
Taiya Inlet. It is possible that all or part of these pods will enter 
the disturbance zone once or twice during the course of the project. 
Therefore, we can conservatively estimate that, because of the 
gregarious nature of killer whales, a single pod of resident (15-20) 
killer whales may occur in the disturbance zone once or twice during 
the course of the project. All other stocks are rare in this area; 
however their range includes southeast Alaska, and therefore they may 
occur in the upper reaches of Lynn Canal into Taiya inlet towards 
Skagway, albeit infrequently. Because of this, it is assumed that the 
Northern resident stock is the stock most likely to be affected. 
However, there is a small chance that a small number of individuals of 
other stocks may be potentially affected. For example, transient stocks 
have only been observed in Lynn Canal (outside of the area of 
ensonification), so it likely that-- if this stock were to enter the 
area of ensonification-- the number of transients exposed would be much 
smaller than the take estimate for all killer whales (e.g. average 
group size of 4-6 individuals with few occurrences in the area), and 
would therefore be a smaller percentage of the stock abundance than 
what is calculated by comparing the total authorized take for all 
killer whales to the abundance of this stock. Therefore, we assume that 
the 60 takes will actually affect a smaller number of the same 
individuals of killer whales from any stock.
    Take requests are assumed to include multiple harassments of the 
same individual(s), resulting in estimates of Take Request Percent of 
Stock that are high compared to actual take that will occur. This is 
the case with the harbor seal (Lynn Canal/Stephens Passage stock). As 
reported, a small number of harbor seals, most of which reside in Taiya 
Inlet year-round, will be exposed to vibratory pile driving and removal 
for nearly 4 months. The total population estimate in the Lynn Canal/
Stephens Passage stock is 9,478 animals over 1.37 million acres of 
area. This is a density of 36 animals within Taiya Inlet. The largest 
Level B harassment Zone within the inlet occupies 21.0 square 
kilometers, which represents less than 0.4 percent of the total 
geographical area occupied by the stock. The great majority of these 
exposures will be to the same animals that have habituated to pile 
driving and pile removal activities within the inlet and the general 
port activities associated with the Skagway waterfront. Given that the 
Taiya Inlet area represents less than 0.4 percent of the total stock 
area, broader impacts to this stock are highly

[[Page 26655]]

unlikely. In addition, marine mammal monitoring for the project can 
provide an early alert in the unlikely event that cumulative exposure 
of seals residing in the area is leading to adverse behavioral or 
physical effects.
    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 mitigation and monitoring 
measures, which are expected to reduce the number of marine mammals 
potentially affected by the proposed action, NMFS finds that small 
numbers of marine mammals will be taken relative to the populations of 
the affected species or stocks.

          Table 7--Estimated Numbers and Percentage of Stock That May Be Exposed to Level B Harassment
----------------------------------------------------------------------------------------------------------------
                                                 Proposed
                   Species                      authorized      Stock(s) abundance estimate \1\    Percentage of
                                                   takes                                            total stock
----------------------------------------------------------------------------------------------------------------
Harbor Seal (Phoca vitulina)................           2,272  9,478.............................              24
Lynn Canal/Stephens Passage Stock...........
Steller Sea Lion (Eumetopias jubatus)
    wDPS Stock..............................           1,184  49,497............................             2.4
    eDPS Stock..............................  ..............  60,131............................             2.0
Harbor Porpoise (Phocoena phocoena)                      168  11,146............................             1.5
 Southeast Alaska Stock.
Dall's porpoise (Phocoenidae dalli) Alaska                45  unknown...........................             n/a
 Stock.
Killer Whale (Orcinus orca)
    Alaska stock............................  ..............  2,347.............................             2.6
    Northern resident stock.................              60  261...............................              23
    Gulf of Alaska stock....................  ..............  587...............................            10.2
    West coast transient stock..............  ..............  243...............................            24.7
Humpback whale (Megaptera novaeangliae)                   84  10,252............................            0.82
 Central North Pacific Stock.
----------------------------------------------------------------------------------------------------------------
\1\ All stock abundance estimates presented here are from the draft 2015 Alaska Stock Assessment Report.

    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 mitigation and monitoring 
measures, which are expected to reduce the number of marine mammals 
potentially affected by the proposed action, NMFS preliminarily finds 
that small numbers of marine mammals will be taken relative to the 
populations of the affected species or stocks.

Impact on Availability of Affected Species for Taking for Subsistence 
Uses

    Alaska Natives have traditionally harvested subsistence resources 
in Alaska for many hundreds of years, particularly Steller sea lions 
and harbor seals. The proposed Project will occur near but not overlap 
the subsistence area used by the villages of Hoonah and Angoon (Wolfe 
et al. 2013). Since all project activities will take place within the 
immediate vicinity of the SOT, the project will not have an adverse 
impact on the availability of marine mammals for subsistence use at 
locations farther away. No disturbance or displacement of sea lions or 
harbor seals from traditional hunting areas by activities associated 
with the SOT project is expected. No changes to availability of 
subsistence resources will result from SOT project activities.

Endangered Species Act (ESA)

    There are two marine mammal species that are listed as endangered 
under the ESA with confirmed or possible occurrence in the study area: 
humpback whales and western DPS of Steller sea lions. Under section 7 
of the ESA, the United States Army Corps of Engineers (USACE) has begun 
consultation with NMFS on the proposed pile driving activities. NMFS 
will also consult internally on the issuance of an IHA under section 
101(a)(5)(D) of the MMPA for this activity. Consultation will be 
concluded prior to a determination on the issuance of an IHA.

National Environmental Policy Act (NEPA)

    NMFS is preparing an Environmental Assessment (EA) in accordance 
with the National Environmental Policy Act (NEPA) and will consider 
comments submitted in response to this notice as part of that process. 
The EA will be posted at https://www.nmfs.noaa.gov/pr/permits/incidental/construction.htm once it is finalized. NMFS is currently 
conducting an analysis, pursuant to NEPA, to determine whether or not 
this proposed activity may have a significant effect on the human 
environment. This analysis will be completed prior to the issuance or 
denial of this proposed IHA.

Proposed Incidental Harassment Authorization

    As a result of these preliminary determinations, we propose to 
issue an IHA to the MOS for conducting the Skagway Gateway Initiative 
Project, provided the previously mentioned mitigation, monitoring, and 
reporting requirements are incorporated. The proposed IHA language is 
provided next.
    This section contains a draft of the IHA. The wording contained in 
this section is proposed for inclusion in the IHA (if issued).
    1. This Incidental Harassment Authorization (IHA) is valid from 
July 1, 2016 through June 30, 2017.
    2. This Authorization is valid only for in-water construction work 
associated with the Skagway Gateway Initiative Project at the Skagway 
Ore Terminal.
    3. General Conditions.
    (a) A copy of this IHA must be in the possession of the MOS, its 
designees, and work crew personnel operating under the authority of 
this IHA.
    (b) The species authorized for taking include humpback whale 
(Megaptera navaeangliae), killer whale (Orcinus orca), Steller sea lion 
(Eumatopius jubatus), harbor porpoise (Phocoena phocoena), Dall's 
porpoise (Phocoenoides dalli), and harbor seal (Phoca vitulina 
richardii).
    (c) The taking, by Level B harassment only, is limited to the 
species listed in condition 3(b). See Table 1 for numbers of take 
authorized.

[[Page 26656]]



                                        Table 1--Authorized Take Numbers
----------------------------------------------------------------------------------------------------------------
                                                                                     Proposed authorized takes
                     Species                        N (animals)   Number of days -------------------------------
                                                                    of activity       Level A         Level B
----------------------------------------------------------------------------------------------------------------
Harbor Seal.....................................              44              74               0           2,272
Steller sea lion................................              32              74               0           1,184
Humpback whale..................................               2              42               0              84
Killer whale....................................              15               4               0              60
Harbor porpoise.................................               2              84               0             168
Dall's porpoise.................................               3              15               0              45
                                                 ---------------------------------------------------------------
    Total exposures.............................  ..............  ..............               0           3,813
----------------------------------------------------------------------------------------------------------------

    (d) The taking by injury (Level A harassment), serious injury, or 
death of any of the species listed in condition 3(b), or any taking of 
any other species of marine mammal is prohibited and may result in the 
modification, suspension, or revocation of this IHA.
    (e) The MOS shall conduct briefings between construction 
supervisors and crews, marine mammal monitoring team, and staff prior 
to the start of all in-water pile driving, and when new personnel join 
the work, in order to explain responsibilities, communication 
procedures, marine mammal monitoring protocol, and operational 
procedures.
    4. Mitigation Measures
    The holder of this Authorization is required to implement the 
following mitigation measures:
    (a) Time Restriction: For all in-water pile driving activities, the 
MOS shall operate only during daylight hours when visual monitoring of 
marine mammals can be conducted. All in-water pile extraction and 
installation shall be completed by March 31, 2017.
    (b) Establishment of Level B Harassment (ZOI)
    (i) For vibratory driving, the Level B harassment area is contained 
within Taiya Inlet, approximately 17 km from the action area. This 
distance will serve as a shutdown zone for all other marine mammals not 
listed in 3(b). During impact driving, the Level B harassment zone 
shall extend to a minimum of 1,585 m for animals listed in 3(b). This 
1,585-meter distance will serve as a shutdown zone for all other marine 
mammals not listed in 3(b).
    (c) Establishment of shutdown zone.
    (i) A 16-meter shutdown zone will be in effect for Steller sea 
lions and harbor seals. The shutdown zone for Level A injury to 
cetaceans would be 74 meters.
    (d) The Level A and Level B harassment zones will be monitored 
throughout the time required to install or extract a pile. If a marine 
mammal is observed entering the Level B harassment zone, a Level B 
exposure will be recorded and behaviors documented. That pile segment 
will be completed without cessation, unless the animal approaches the 
Level A shutdown zone. Pile installation will be halted immediately 
before the animal enters the Level A zone.
    (e) Use of Ramp Up/Soft Start.
    (i) The project will utilize soft start techniques for all 
vibratory and impact pile driving. We require the MOS to initiate sound 
from vibratory hammers for fifteen seconds at reduced energy followed 
by a 1-minute waiting period, with the procedure repeated two 
additional times. For impact driving, we require an initial set of 
three strikes from the impact hammer at reduced energy, followed by a 
1-minute waiting period, then two subsequent three strike sets.
    (ii) Soft start will be required at the beginning of each day's 
pile driving work and at any time following a cessation of pile driving 
of 30 minutes or longer.
    (iii) If a marine mammal is present within the shutdown zone, 
ramping up will be delayed until the animal(s) leaves the Level A 
harassment zone. Activity will begin only after the MMO has determined, 
through sighting, that the animal(s) has moved outside the Level A 
harassment zone or if 15 minutes have passed without re-sighting of the 
individual.
    (iv) If a marine mammal is present in the Level B harassment zone, 
ramping up will begin and a Level B take will be documented. Ramping up 
will occur when these species are in the Level B harassment zone 
whether they entered the Level B zone from the Level A zone, or from 
outside the project area.
    (v) If any marine mammal other than those listed in this IHA is 
present in the Level B harassment zone, ramping up will be delayed 
until the animal(s) leaves the zone. Ramping up will begin only after 
the MMO has determined, through sighting, that the animal(s) has moved 
outside the harassment zone.
    (f) Sound attenuation devices--Approved sound attenuation devices 
shall be used during impact pile driving operations. The MOS shall 
implement the necessary contractual requirements to ensure that such 
devices are capable of achieving optimal performance, and that 
deployment of the device is implemented properly such that no reduction 
in performance may be attributable to faulty deployment.
    (g) Contaminant exposure mitigation measures--A silt curtain and a 
contamination sequence will be used during all dredging activities.
    (i) The silt curtain will be constructed of flexible, reinforced, 
thermoplastic material with flotation material in the upper hem and 
ballast material in the lower hem. The curtain will be placed in the 
water surrounding the dredging operation. The specifications will 
require that the Contractor maintain the silt curtain(s) around either 
the point of dredging or the dredging area at the contractor's 
discretion. The effectiveness of the silt curtain will be monitored 
during construction.
    (ii) The contractor will prioritize the removal of the most 
impacted areas (i.e., the area with the highest observed concentrations 
of contaminants of concern) before the surrounding areas.
    (h) Standard mitigation measures.
    (i) Conduct briefings between construction supervisors and crews, 
marine mammal monitoring team, and MOS staff prior to the start of all 
pile driving and extraction activity, and when new personnel join the 
work, in order to explain responsibilities, communication procedures, 
marine mammal monitoring protocol, and operational procedures.
    (ii) 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.
    (i) The MOS shall establish monitoring locations as described 
below.
    5. Monitoring and Reporting

[[Page 26657]]

    The holder of this Authorization is required to report all 
monitoring conducted under the IHA within 90 calendar days of the 
completion of the marine mammal monitoring
    (a) Visual Marine Mammal Monitoring and Observation
    (i) At least one individual meeting the minimum qualifications 
identified in Appendix A of the application by the MOS will monitor the 
shutdown and Level B harassment zones during impact and vibratory pile 
driving.
    (ii) During pile driving and extraction, the shutdown zone, as 
described in 4(b), will be monitored and maintained. Pile installation 
or extraction will not commence or will be suspended temporarily if any 
marine mammals are observed within or approaching the area of potential 
disturbance.
    (iii) The area within the Level B harassment threshold for pile 
driving and extraction will be monitored by observers stationed to 
provide adequate view of the harassment zone. Marine mammal presence 
within this Level B harassment zone, if any, will be monitored. Pile 
driving activity will not be stopped if marine mammals are found to be 
present. Any marine mammal documented within the Level B harassment 
zone during impact driving would constitute a Level B take 
(harassment), and will be recorded and reported as such.
    (iv) The individuals will scan the waters within each monitoring 
zone activity using binoculars, spotting scopes, and visual 
observation.
    (v) If waters exceed a sea-state, or poor environmental conditions 
restricts the observers' ability to make observations (e.g. excessive 
wind or fog), impact pile installation will cease until conditions 
allow the resumption of monitoring.
    (vi) The waters will be scanned 30 minutes prior to commencing pile 
driving or removal at the beginning of each day, and prior to 
commencing pile driving or removal after any stoppage of 30 minutes or 
greater. If marine mammals enter or are observed within the designated 
marine mammal shutdown zone during or 30 minutes prior to impact pile 
driving, the monitors will notify the on-site construction manager to 
not begin until the animal has moved outside the designated radius.
    (vii) The waters will continue to be scanned for at least 30 
minutes after pile driving has completed each day,
    (b) Data Collection
    (i) Observers are required to use approved data forms. Among other 
pieces of information, the MOS 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 MOS will attempt to 
distinguish between the number of individual animals taken and the 
number of incidents of take. At a minimum, the following information be 
collected on the sighting forms:
    1. Date and time that monitored activity begins or ends;
    2. Construction activities occurring during each observation 
period;
    3. Weather parameters (e.g., percent cover, visibility);
    4. Water conditions (e.g., sea state, tide state);
    5. Species, numbers, and, if possible, sex and age class of marine 
mammals;
    6. Description of any observable marine mammal behavior patterns, 
including bearing and direction of travel and distance from pile 
driving activity;
    7. Distance from pile driving activities to marine mammals and 
distance from the marine mammals to the observation point;
    8. Locations of all marine mammal observations; and
    9. Other human activity in the area.
    (c) Reporting Measures
    (i) In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA, 
such as an injury (Level A harassment), serious injury or mortality 
(e.g., ship-strike, gear interaction, and/or entanglement), the MOS 
would immediately cease the specified activities and immediately report 
the incident to the Chief of the Permits and Conservation Division, 
Office of Protected Resources, NMFS, and the Alaska Regional Stranding 
Coordinators. The report would include the following information:
    1. Time, date, and location (latitude/longitude) of the incident;
    2. Name and type of vessel involved;
    3. Vessel's speed during and leading up to the incident;
    4. Description of the incident;
    5. Status of all sound source use in the 24 hours preceding the 
incident;
    6. Water depth;
    7. Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    8. Description of all marine mammal observations in the 24 hours 
preceding the incident;
    9. Species identification or description of the animal(s) involved;
    10. Fate of the animal(s); and
    11. Photographs or video footage of the animal(s) (if equipment is 
available).
    (ii) Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with the MOS to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. The MOS would not be able 
to resume their activities until notified by NMFS via letter, email, or 
telephone.
    (iii) In the event that the MOS discovers an injured or dead marine 
mammal, and the lead MMO determines that the cause of the injury or 
death is unknown and the death is relatively recent (i.e., in less than 
a moderate state of decomposition as described in the next paragraph), 
the MOS would immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the Alaska Stranding Hotline and/or by email to the Alaska Regional 
Stranding Coordinators. The report would include the same information 
identified in the paragraph above. Activities would be able to continue 
while NMFS reviews the circumstances of the incident. NMFS would work 
with the MOS to determine whether modifications in the activities are 
appropriate.
    (iv) In the event that the MOS discovers an injured or dead marine 
mammal, and the lead MMO determines that the injury or death is not 
associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), the MOS would report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the NMFS Alaska Stranding Hotline and/or 
by email to the Alaska Regional Stranding Coordinator, within 24 hours 
of the discovery. The DOT&PF would provide photographs or video footage 
(if available) or other documentation of the stranded animal sighting 
to NMFS and the Marine Mammal Stranding Network.
    6. MOS is required to comply with the Reasonable and Prudent 
Measures and Terms and Conditions of the ITS corresponding to NMFS' 
Biological Opinion issued to both U.S. Army Corps of Engineers and 
NMFS' Office of Protected Resources.
    7. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein, or if 
NMFS determines the authorized taking is having more than a negligible 
impact on the species or stock of affected marine mammals.

[[Page 26658]]

Request for Public Comments

    NMFS requests comment on our analysis, the draft authorization, and 
any other aspect of the Notice of Proposed IHA for the Skagway Gateway 
Initiative Project. Please include with your comments any supporting 
data or literature citations to help inform our final decision on MOS's 
request for an MMPA authorization.

    Dated: April 22, 2016.
Perry F. Gayaldo,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2016-10266 Filed 5-2-16; 8:45 am]
 BILLING CODE 3510-22-P