Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Dock Replacement Project, 79822-79843 [2015-32155]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 80, Number 246 (Wednesday, December 23, 2015)]
[Notices]
[Pages 79822-79843]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-32155]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XE340


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a Dock Replacement Project

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

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

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SUMMARY: NMFS has received a request from UniSea, Inc., for 
authorization to take marine mammals incidental to construction 
activities as part of a dock construction project at a commercial fish 
processing facility in Unalaska, AK. Pursuant to the Marine Mammal 
Protection Act (MMPA), NMFS is requesting comments on its proposal to 
issue an incidental harassment authorization (IHA) to UniSea to 
incidentally take marine mammals, by Level B Harassment only, during 
the specified activity.

DATES: Comments and information must be received no later than January 
22, 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.Carduner@noaa.gov.
    Instructions: Comments sent by any other method, to any other 
address or individual, or received after the end of the comment period, 
may not be considered by NMFS. 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 for public 
viewing on the Internet at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm without change. All personal identifying information 
(e.g., name, address), confidential business information, or otherwise 
sensitive information submitted voluntarily by the sender will be 
publicly accessible.

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

SUPPLEMENTARY INFORMATION: 

Availability

    An electronic copy of UniSea'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: www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing 
these documents, please call the contact listed under FOR FURTHER 
INFORMATION CONTACT.

National Environmental Policy Act (NEPA)

    NMFS is preparing an Environmental Assessment (EA) for the proposed 
issuance of an IHA, pursuant to NEPA, to determine whether or not this 
proposed activity may have significant direct, indirect and cumulative 
effects on the human environment. This analysis will be completed prior 
to the issuance or denial of this proposed IHA. We will review all 
comments submitted in response to this notice as we complete the NEPA 
process, prior to a final decision on the incidental take authorization 
request. The EA will be posted at https://www.nmfs.noaa.gov/pr/permits/incidental/construction.htm when 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,

[[Page 79823]]

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 (1) have a negligible impact on the species 
or stock(s), and (2) 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.
    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 IHA. The establishment of these prescriptions 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, 
section 3(18) of the MMPA defines ``harassment'' as any act of pursuit, 
torment, or annoyance which: has the potential to injure a marine 
mammal or marine mammal stock in the wild [Level A harassment]; or 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 June 10, 2015, we received a request from UniSea for 
authorization to take marine mammals incidental to pile driving and 
pile removal associated with construction of a commercial fishing dock 
in Iliuliuk Harbor, a small harbor in the Aleutian Islands. UniSea 
submitted revised versions of the request on September 28, 2015, and 
December 2, 2015. The latter of these was deemed adequate and complete. 
UniSea proposes to replace the existing dock with an 80 foot by 400 
foot open cell sheet pile dock between March 1, 2016 and February 28, 
2017.
    The use of both vibratory and impact pile driving is expected to 
produce underwater sound at levels that have the potential to result in 
behavioral harassment of marine mammals. Species with the expected 
potential to be present during all or a portion of the in-water work 
window include the Steller sea lion (Eumetopias jubatus) and harbor 
seal (Phoca vitulina). These species may occur year-round in Iliuliuk 
Harbor.

Description of the Specified Activity

Overview

    UniSea's ``G1'' dock is located in the commercial fishing port of 
Iliuliuk Harbor in Unalaska, AK, and supports activities that occur in 
nearby fish processing facilities. The existing dock is being replaced 
because it is currently partially unusable, and because the company's 
plans for expansion necessitate a larger dock with increased capacity.
    UniSea proposes to demolish the existing structure by removing the 
concrete deck, steel superstructure, and all attached appurtenances/
structures, and extracting the existing steel support piles with a 
vibratory hammer. Starting at the existing ``G2'' sheet pile dock, the 
sheet pile of the new dock will then be installed. After completion of 
a few cells, the cells will be incrementally filled with clean material 
as the work progresses with bulldozers, wheel loaders, and compaction 
equipment. After all of the sheet piles are installed and the bulkhead 
is backfilled, concrete surfacing, fender piles, mooring cleats, and 
other appurtenances will be installed. Sound attenuation measures 
(i.e., bubble curtain) will be used during all impact hammer 
operations. Note that throughout the remainder of this document the 
term ``pile driving'' refers to both pile driving and pile removal, 
except where specified.

Dates and Duration

    UniSea plans to conduct all in-water construction work during the 
period from March 1, 2016 to February 28, 2017. The total construction 
time, including removal of old piles and construction of the new dock, 
is expected to take no more than 180 days. Durations are conservative, 
and the actual amount of time to install and remove piles may be less 
than estimated. In[hyphen]water and over-water construction of Phase 1 
(all sheet pile installation and some pipe pile installation) is 
planned to occur between approximately March 1, 2016 and October 31, 
2016. Phase 2 (remaining pipe pile installation) is planned to occur 
between approximately November 1, 2016 and December 1, 2017. It is 
possible that work could be completed within one year; however, if it 
is not, UniSea will apply for a second IHA for any additional 
construction work that was not completed in the first year of the 
project.
    In the summer months (May-August), 12 hour work days in daylight 
will likely be feasible given the extended daylight hours. In winter 
months (September-April), 8 hour to 10 hour work days in daylight will 
likely be achievable. The daily construction window for pile driving or 
removal will begin no sooner than 30 minutes after sunrise to allow for 
initial marine mammal monitoring to take place, and will end 30 minutes 
before sunset to allow for post-construction marine mammal monitoring.
    Duration estimates for each of the pile installation and removal 
elements are described below:
     Vibratory Pile Removal: Vibratory pile removal will take 
10 minutes or less per pile over a maximum duration of 30 days. Total 
maximum vibratory pile removal time for 75 piles is 13 hours.
     Vibratory Pile Driving (Sheet Pile): Vibratory pile 
driving of sheet pile will take 5 minutes or less per pile over a 
maximum duration of 90 days. Total maximum driving time for 890 sheet 
piles is 75 hours.
     Vibratory Pile Driving (Support Piles): Vibratory pile 
driving of support piles will take 10 minutes or less per pile over a 
maximum duration of 30 days (concurrent with impact pile driving). 
Total maximum driving time for 64 piles is 11 hours.
     Impact Pile Driving: Impact pile driving of dolphin and 
other support piles will take 30 minutes or less per pile over a 
maximum duration of 60 days. Total maximum driving time for 78 piles is 
39 hours.
     Drilling: Drilling for installation of dolphin and other 
support piles will take 6 hours or less per pile over a maximum 
duration of 50 days (concurrent with impact pile driving).

[[Page 79824]]

Total maximum drilling time for 24 piles is 144 hours.
    The duration estimates provided above are considered generous 
enough to account for temporary support piles installed by the 
construction contractor for template structures to accommodate pile 
driving. Only one pile driver will be operating at any given time, and 
impact and vibratory driving are not anticipated to occur concurrently 
(i.e., only one method of driving will be used at a given time).

Specific Geographic Region

    The project location is in the eastern Aleutian Islands, west of 
mainland Alaska. The UniSea dock is located in Iliuliuk Harbor, a small 
harbor on an islet called Amaknak Island that is connected by a small 
bridge to the larger Unalaska Island. Iliuliuk Harbor is located 
between Captains Bay and Iliuliuk Bay, with Unalaska Bay to the north 
opening into the Bering Sea. Please see Figure 1 and Section 2 of 
UniSea's IHA application for detailed information about the specific 
geographic region.

Detailed Description of Activities

    UniSea proposes to replace the ``G1'' dock mainly because the 
existing dock is partially unusable as a large portion of the dock is 
condemned due to corrosion and damage to existing steel piles. 
Additionally, the current UniSea processing plant is nearing capacity 
and the company plans to build new processing facilities that will 
ultimately be located at the shoreline and possibly encroach onto the 
new dock, necessitating a fill dock design rather than a pile-supported 
structure.
    The proposed action includes the demolition and removal of the 
existing dock structure and the installation of a new 80 foot by 400 
foot open cell sheet pileTM (OCSP TM) dock. The 
existing structure will be demolished by removing the concrete deck, 
steel superstructure, and all attached appurtenances/structures, and 
extracting the existing steel support piles with a vibratory hammer. 
Starting at the existing G2 sheet pile dock, the sheet pile of the new 
dock will be installed. After completion of a few cells, the cells will 
be incrementally filled with clean material as the work progresses with 
bulldozers, wheel loaders, and compaction equipment. After all of the 
sheet piles are installed and the bulkhead is backfilled, concrete 
surfacing, fender piles, mooring cleats, and other appurtenances will 
be installed.
    The construction process is described below; further detail on the 
process can be found in Section 1 of the IHA application. The number 
and type of piles and related construction equipment proposed for 
installation as part of the construction process are as follows (and 
are shown in Table 1):
     Approximately fifty 24-inch diameter fiber-reinforced 
polymer (FRP) composite fender piles;
     Approximately nine 24-inch diameter steel support piles 
along the dock face and for crab brailer support;
     One 24-inch diameter steel plug/closure pile to retain 
fill between the existing and new sheet pile cells at the north end of 
the project;
     Two dolphins, each includes: five 24-inch diameter steel 
support piles (10 total) and two 24-inch diameter steel fender pin 
piles (four total);
     Four 50 foot steel catwalks with intermediate supports of 
two 18-inch diameter steel piles each (four piles total); and
     Seawater intake sheet pile (PS31 flat sheet piles) 
structure approximately 90 foot by 85 foot, access ramp, and armor rock 
erosion protection (3,400 cubic yards of rock fill and 400 cubic yards 
of armor rock).

  Table 1--Anticipated Types and Quantities of Construction Equipment Requiring Pile Driving or Removal During
                                          Proposed Construction Project
----------------------------------------------------------------------------------------------------------------
                                          Estimated number, size
                 Item                            and type                      Construction technique
----------------------------------------------------------------------------------------------------------------
Proposed piles to be removed..........  73 (steel)...............  Vibratory.
                                        72 (timber)..............
Proposed piles to be installed........  24 (24'' Steel)..........  Vibratory or Impact.
                                        4 (18'' Steel)...........
                                        50 (24'' FRP)............
Estimated temporary piles to be         180 (18'' Steel).........  Vibratory or Impact.
 installed.
Proposed sheet piles..................  887......................  Vibratory.
----------------------------------------------------------------------------------------------------------------

    The existing dock (consisting of steel support piles, steel 
superstructure, and concrete deck) will be completely removed for 
construction of the new G1 dock. Vibratory pile removal will generally 
consist of clamping the ``jaws'' of the vibratory hammer to the pile to 
be removed, extracting the pile (with vibratory hammer turned on) to 
the point where the pile is temporarily secured and removal can be 
completed with crane line rigging. The pile will then be completely 
removed from the water by hoisting with crane line rigging, and then 
placed on the ground or deck of a barge. In addition to vibratory pile 
removal, demolition of the existing dock and removal of existing 
riprap/obstructions will be performed with track excavators, loaders, 
cranes, barges, cutting equipment, and labor forces. The existing dock 
(consisting of steel support piles, steel superstructure, and concrete 
deck) will be completely removed for construction of the new dock. The 
contractor will be required to dispose of (or salvage) demolished items 
in accordance with all federal, state, and local regulations. 
Dewatering will not be required as all extraction will take place from 
the existing dock, from shore, and/or from a work barge.
    The new sheet pile bulkhead dock and seawater intake structure will 
then be installed utilizing a crane and vibratory hammer. UniSea 
anticipates that the largest vibratory hammer that may be used for the 
project will have an eccentric moment of 6,600 inch-pounds (``eccentric 
moment'' is one of two key factors in vibratory hammer performance--the 
other being engine power--and is responsible for creating enough 
amplitude to exceed the elastic range of the substrate). After all 
piles of several sheet pile cells have been installed, clean rock fill 
will be placed within the sheet pile cells from the shore. This process 
will continue sequentially until all of the sheet pile cells are 
installed and backfilled. See Figure 2 in the IHA application for a 
photo of sheet pile installation using a vibratory hammer.
    Approximately 50 fiber-reinforced polymer (FRP) composite fender 
piles will then be installed along the face of the new sheet pile dock, 
fastened to the face at the top, and cut to elevation.

[[Page 79825]]

Initial driving of the FRP fender piles will be done with a vibratory 
or impact hammer, and final seating of the piles into the shallow 
bedrock will be done with an impact hammer. See Figure 3 in the IHA 
application for a photo of the FRP composite fender pile. Two dolphins, 
each with five 24-inch diameter steel support piles each and two 24-
inch diameter steel fender pin piles, will be installed and cut to 
elevation for installation of a structural steel cap. The support piles 
will be driven and seated into shallow bedrock with an impact hammer. 
See Figure 4 in the IHA application for a photo of the dolphin support 
piles being driven with an impact hammer. After the piles have been 
firmly seated into the bedrock, drilling equipment will be used to 
drill a shaft in the bedrock (down the center of the pipe pile) for 
installation of rock anchors. The rock anchors will consist of a high-
strength steel rod grouted into the drilled shaft and tensioned against 
bearing plates inside the pile. Rock anchors are required in shallow 
bedrock conditions for the piles to resist tensile loads from vessel 
mooring and berthing.
    Fender support/pin piles will then be installed and cut to 
elevation. The fender support/pin piles will either be installed in a 
socket drilled into the shallow bedrock (driven with an impact hammer 
and possibly a vibratory hammer down into the socket), by the down-the-
hole drilling technique (described below), or with a rock anchor 
system. Pre-assembled fender systems (energy absorbers, sleeve piles, 
steel framing, and fender panels) will be lifted and installed onto 
fender support piles via crane.
    Miscellaneous support piles (including catwalk and dock face 
support piles) will then be installed and cut to elevation. 
Installation methods for the miscellaneous support piles will be 
similar to the fender support piles (described above). Temporary 
support piles for the contractor's pile driving template structures 
will be installed to aid with construction and removed after the 
permanent sheet piles or support piles have been installed. 
Installation methods for the temporary support piles will be similar to 
those used for the fender support piles (described above). Temporary 
support piles will likely be steel H-piles (18 inch or smaller) or 
steel round piles (18 inch diameter or smaller). The sheet pile 
structures consist of 14 cells, and there are two dolphin and two 
catwalk support structures. It is estimated that upwards of ten 
temporary support piles will be used per cell for the sheet pile 
structures, and upwards of eight piles per dolphin and catwalk support 
location (this represents a best estimate of the number of temporary 
piles that will be necessary based on previous projects, however the 
actual number will be determined by the contractor).
    Down-the-hole drilling entails the use of a rotary drill bit that 
is impacted when hard material is encountered. The pounding action 
takes place where the drill bit encounters the resistant material 
underground, rather than at the surface as would be the case for impact 
or vibratory pile driving. The piling is fit over the drill with the 
drill head extending beneath the pile, and as the drill advances 
downward, so does the pile. When the proper depth is achieved, the 
drill is retracted and the piling is left in place. This method 
eliminates much of the high-energy sound associated with traditional 
pile driving methods. For the purposes of this proposed authorization 
we assume that fender support/pin piles, miscellaneous support piles 
(including catwalk and dock face support piles), and temporary support 
piles (for the contractor's pile driving template structures) would be 
installed using impact driving. However, if they are ultimately 
installed by down-the-hole drilling this would not change the total 
amount of effort, i.e. down-the-hole drilling would occur instead of, 
not in addition to, impact driving for installation of fender support/
pin piles, miscellaneous support piles, and temporary support piles.
    Additional construction work, such as concrete dock surfacing, will 
take place at or near the surface of the dock and will occur above 
water. Because this work is not expected to result in harassment of 
marine mammals, we do not summarize it here. Details of all planned 
construction work, and photos of many of the construction techniques 
described above, can be found in Section 1 of UniSea's IHA application.

Description of Marine Mammals in the Area of the Specified Activity

    Marine waters near Unalaska Island support many species of marine 
mammals, including pinnipeds and cetaceans; however, the number of 
species regularly occurring near the project location is limited. There 
are three marine mammal species under NMFS' jurisdiction with recorded 
occurrence in Iliuliuk Harbor during the past 15 years, including one 
cetacean and two pinnipeds. Steller sea lions are the most common 
marine mammals in the project area and are part of the western Distinct 
Population Segment (DPS) that is listed as Endangered under the 
Endangered Species Act (ESA). Harbor seals (Phoca vitulina) may also 
occur in the project area, though less frequently and in lower 
abundance than Steller sea lions. The humpback whale (Megaptera 
novaeangliae), although seasonally abundant in Unalaska Bay, is not 
typically present in Iliuliuk Harbor. A single humpback whale was 
observed beneath the bridge that connects Amaknak Island and Unalaska 
Island, moving in the direction of Iliuliuk Harbor, in September 2015 
(pers. comm., L. Baughman, PND Engineers, to J. Carduner, NMFS, Oct. 
12, 2015); no other sightings of humpback whales in Iliuliuk Harbor 
have been recorded and no records are found in the literature. In the 
summer months, the majority of humpback whales from the central North 
Pacific stock are found in the feeding grounds of the Aleutian Islands, 
Bering Sea, Gulf of Alaska, and Southeast Alaska/northern British 
Columbia, with high densities of whales found in the eastern Aleutian 
Islands, including along the north side of Unalaska Island (Allen and 
Angliss 2014b). Despite their relatively high abundance in Unalaska Bay 
during summer months, their presence within Iliuliuk Harbor is 
sufficiently rare that we do not believe there is a reasonable 
likelihood of their occurrence in the project area during the period of 
validity for the proposed IHA. Thus we do not propose to authorize the 
incidental harassment of humpback whales as a result of the proposed 
project; as such, the humpback whale is not carried forward for further 
analysis beyond this section.
    We have reviewed UniSea's detailed species descriptions, including 
life history information, for accuracy and completeness and refer the 
reader to Sections 3 and 4 of UniSea's application, rather than 
reprinting the information here. Please also refer to NMFS' Web site 
(www.nmfs.noaa.gov/pr/species/mammals/) for generalized species 
accounts.
    Table 2 lists the marine mammal species with expected potential for 
occurrence in the vicinity of the project during the project timeframe 
and summarizes key information regarding stock status and abundance. 
Taxonomically, we follow Committee on Taxonomy (2015). Please see NMFS' 
Stock Assessment Reports (SAR), available at www.nmfs.noaa.gov/pr/sars, 
for more detailed accounts of these stocks' status and abundance. The 
harbor seal and Steller sea lion are addressed in the Alaska SARs 
(e.g., Allen and Angliss, 2012, 2014).
    In the species accounts provided here, we offer a brief 
introduction to the species and relevant stock as well as available 
information regarding

[[Page 79826]]

population trends and threats, and describe any information regarding 
local occurrence.

                                   Table 2--Marine Mammals Potentially Present in the Vicinity of the Project Location
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Stock abundance                                    Relative occurrence
                                                           ESA/MMPA status;       (CV; Nmin; most                                    in Iliuliuk Harbor;
             Species                       Stock          Strategic (Y/N)\1\     recent abundance        PBR\3\      Annual M/SI\4\       season of
                                                                                    survey)\2\                                            occurrence
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Otariidae (eared seals and
 sea lions):
    Steller sea lion.............  Western U.S.          E/D; N..............  55,422 (n/a; 48,676;             292           234.7  common; year-round
                                                                                2008-11)\8\.                                          (greater abundance
                                                                                                                                      in summer).
--------------------------------------------------------------------------------------------------------------------------------------------------------
Family Phocidae (earless seals):
    Harbor seal..................  Aleutian Islands....  -; N................  3,579\5\ (0.092;                  99            93.1  occasional; year-
                                                                                3,313; 2004).                                         round.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ ESA status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed under the ESA or
  designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality exceeds PBR (see
  footnote 3) or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ CV is coefficient of variation; Nmin is the minimum estimate of stock abundance. In some cases, CV is not applicable. For killer whales, the
  abundance values represent direct counts of individually identifiable animals; therefore there is only a single abundance estimate with no associated
  CV. For certain stocks of pinnipeds, abundance estimates are based upon observations of animals (often pups) ashore multiplied by some correction
  factor derived from knowledge of the species (or similar species) life history to arrive at a best abundance estimate; therefore, there is no
  associated CV. In these cases, the minimum abundance may represent actual counts of all animals ashore.
\3\ Potential biological removal, defined by the MMPA as the maximum number of animals, not including natural mortalities, that may be removed from a
  marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population size (OSP).
\4\ These values, found in NMFS' SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g., commercial
  fisheries, subsistence hunting, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value.
\5\ Abundance estimate for this stock is greater than ten years old and is therefore not considered current. We nevertheless present the most recent
  abundance estimate, as this represents the best available information for use in this document.

Steller Sea Lion

    Steller sea lions are distributed mainly around the coasts to the 
outer continental shelf along the North Pacific rim from northern 
Hokkaido, Japan through the Kuril Islands and Okhotsk Sea, Aleutian 
Islands and central Bering Sea, southern coast of Alaska and south to 
California (Loughlin et al., 1984). Based on distribution, population 
response, and phenotypic and genotypic data, two separate stocks of 
Steller sea lions are recognized within U. S. waters, with the 
population divided into western and eastern distinct population 
segments (DPS) at 144[deg] W (Cape Suckling, Alaska) (Loughlin, 1997). 
The western DPS includes Steller sea lions that reside in the central 
and western Gulf of Alaska, Aleutian Islands, as well as those that 
inhabit the coastal waters and breed in Asia (e.g., Japan and Russia). 
Only the western DPS is considered in this proposed authorization 
because the eastern DPS occurs outside the geographic area under 
consideration.
    The species as a whole was ESA-listed as threatened in 1990 (55 FR 
49204) because of significant declines in the population which may have 
been caused by nutritional stress due to competition with commercial 
fisheries, environmental change, disease, killer whale predation, 
incidental take, and shooting (illegal and legal). In 1997, the species 
was divided into two separate DPSs, as described above, and the western 
DPS was reclassified as endangered under the ESA because of its 
continued decline since the initial listing in 1990 (62 FR 24345).
    The most recent comprehensive estimate of the abundance of the 
western DPS in Alaska is 55,422 individuals (both pups and non-pups), 
based on aerial surveys of non-pups conducted from 2008-2011 and 
estimates of total pup production (Allen and Angliss 2014a). This 
figure represents a marked decline from abundance estimates in the 
1950s (N = 140,000) and 1970s (N = 110,000). Pup counts in the Western 
DPS in Alaska overall increased at 1.8 percent annually between 2000 
and 2014; non-up counts increased at 2.2 percent annually over the same 
period (Fritz et al. 2015). However, survey data collected since 2000 
indicate that the population decline continues in the central and 
western Aleutian Islands while populations east of Samalga Pass 
(~170[deg] W) have increased (Allen and Angliss 2014a). Survival rates 
east of Samalga Pass have rebounded to nearly the same levels estimated 
for the 1970s, prior to the decline in abundance. In addition, 
population models indicate that natality among the increasing 
population east of Samalga Pass in the period 2000-2012 may not be 
significantly different from rates estimated for the 1970s. The 
proposed project location in Iliuliuk Harbor is approximately 220 km 
east of Samalga Pass.
    Steller sea lions are the most abundant marine mammals in the 
project area. Data from the NOAA National Marine Mammal Laboratory 
(NMML) surveys of haulouts on Unalaska Island suggest the Steller sea 
lion haulouts nearest to the project location are at Priest Rock (on 
the east side of the entrance to Unalaska Bay, approximately 19 km from 
the project site), Cape Wislow (on the northwest side of the entrance 
to Unalaska Bay, approximately 19 km from the project site) and Bishop 
Point (west of Cape Wislow on the North side of Unalaska Island, 
approximately 27 km from the project site). Bishop Point appears to be 
the most actively utilized haulout of the three, with a mean of 193 
individual sea lions observed over 36 separate surveys

[[Page 79827]]

from 1960 to 2014, and more recent surveys (2004-2014) showing a mean 
of 225 individuals (all of these surveys were conducted in June or July 
when Steller sea lion abundance would typically be highest at haulouts 
in the Aleutians). Priest Rock survey data show a mean of 12 
individuals observed since 1994, with higher totals recorded recently 
(107 individuals counted in 2014). Cape Wislow survey data show 60 
individuals observed in 1989, with no sea lions observed at the site 
during the 20 surveys that have occurred there from 1990 to 2014.
    Based on data from NMML breeding season surveys (conducted in June 
and July), the population of Steller sea lions in the eastern Aleutian 
Islands (from Unimak Island through Umnak Island, 163-169[deg]W) has 
been increasing at 2-3% per year since 2000. Local abundance in the 
breeding season is generally higher overall than in the non-breeding 
season, with counts on land approximately twice as much as those 
observed in winter, as sea lions spend more time at sea feeding during 
the winter months. Most large males leave the Aleutian Islands and head 
north during the winter, feeding off the ice edge, thus adult females 
and juveniles make up the majority of the local population during the 
nonbreeding season (pers. comm. L. Fritz, NMML, to J. Carduner, NMFS, 
Oct. 8, 2015).
    Steller sea lions are not known to haul out in the project area, 
though individuals are observed with regularity in the water within 
Iliuliuk Harbor. The number of sea lions in the immediate project area 
varies depending on the season and the on the presence of fishing 
vessels unloading their catch at the seafood processing facilities in 
the harbor. Sea lions are likely drawn to the project location by the 
abundant and predictable sources of food provided by commercial fishing 
vessels and fish processing facilities. Based on accounts from UniSea 
personnel, sea lions are sighted more often when fishing boats are 
docked at the project site and are often observed foraging near fishing 
boats that are docked at the UniSea facility, suggesting sea lions in 
the Iliuliuk Harbor area are habituated to the presence of fishing 
vessels and are likely conditioned to associating fishing boats with 
easy access to food.

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. They 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). 
Only the Aleutian Islands stock is considered in this application 
because other stocks occur outside the geographic area under 
consideration. Distribution of the Aleutian Islands stock extends from 
Ugamak Island (southwest of Unimak Island in the Eastern Aleutians) 
west to Attu Island (the westernmost Aleutian Island in the U.S.). The 
abundance estimate for the Aleutian Islands stock is 3,579; however, 
this estimate is based on survey data that is over 10 years old. The 
current statewide abundance estimate for Alaskan harbor seals is 
152,602 based on aerial survey data collected during 1998-2007 (Allen 
and Angliss 2012).
    Surveying harbor seals in the Aleutian Islands is notoriously 
difficult as the islands are often blanketed with fog or high winds 
that limit aerial surveys to narrow windows of time. The logistics of 
surveying the entire length of the Aleutian Chain are also quite 
difficult with limited airports and limited access to fuel. As a 
result, available survey data for the Aleutian Islands harbor seal 
stock are extremely limited. The current population trend in the 
Aleutian Islands is unknown. Additionally, the haul-out patterns of 
harbor seals in the Aleutian Islands have not been studied, and there 
is no stock specific estimate of a survey correction factor.
    Small et al. (2008) compared harbor seal counts from 106 Aleutian 
islands surveyed in 1977-1982 (8,601 seals) with counts from the same 
islands during a 1999 aerial survey (2,859 seals). Counts decreased at 
a majority of the islands surveyed. A 45% decline was estimated in the 
Eastern Aleutians (n = 35 islands), with overall estimates for the 
entire Aleutian Islands chain showing a 67% decline during the 
approximate 20-year period. Seal counts decreased at the majority of 
islands in each region, the number of islands with over 100 seals 
decreased ~70%, and the number of islands with no seals counted 
increased approximately 80%, indicating that harbor seal abundance 
throughout the Aleutian Islands was substantially lower in the late 
1990s than in the 1970s and 1980s (Small et al. 2008).
    Harbor seals are only occasionally seen in Iliuliuk Harbor. No 
pupping or haulout sites exist within the project area. The closest 
known harbor seal haulout to the G1 dock is located approximately 3 km 
away on the northern tip of Hog Island in Unalaska Bay; NMML survey 
data shows an average of ~11 seals observed at the site over the course 
of four surveys from 2008-2010. Surveys were conducted only in late 
July and August, thus seasonal information on abundance or distribution 
is not available. NMML survey data suggest there are at least six other 
harbor seal haulouts in and around Unalaska Bay that are further from 
the project site; the maximum number of seals observed at any of these 
haulouts has not exceeded 39 individuals at any one time.

Potential Effects of the Specified Activity on Marine Mammals

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals. The 
``Estimated Take by Incidental Harassment'' section later in this 
document will include a quantitative analysis of the number of 
individuals that are expected to be taken by this activity. The 
``Negligible Impact Analysis'' section will 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, the ``Proposed Mitigation'' section, and the 
``Anticipated Effects on Marine Mammal Habitat'' 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 the construction techniques proposed for 
use.

Description of Sound Sources

    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in hertz (Hz) or cycles per second. Wavelength is the 
distance between two peaks of a sound wave; lower frequency sounds have 
longer wavelengths than higher frequency sounds and attenuate

[[Page 79828]]

(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 [micro]Pa and all airborne sound levels 
in this document are referenced to a pressure of 20 [micro]Pa.
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse, and 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.
    Known sound levels and frequency ranges associated with 
anthropogenic sources similar to those that would be used for this 
project are summarized in Table 3. Details of the source types are 
described in the following text.

                          Table 3--Representative Sound Levels of Anthropogenic Sources
----------------------------------------------------------------------------------------------------------------
                                             Frequency
              Sound source                  range (Hz)      Underwater sound level             Reference
----------------------------------------------------------------------------------------------------------------
Vibratory driving of 72-in steel pipe           10-1,500  180 dB rms at 10 m........  Reyff, 2007.
 pile.
Impact driving of 36-in steel pipe pile.        10-1,500  195 dB rms at 10 m........  Laughlin, 2007.
Impact driving of 66-in cast-in-steel-          10-1,500  195 dB rms at 10 m........  Reviewed in Hastings and
 shell (CISS) pile.                                                                    Popper, 2005.
----------------------------------------------------------------------------------------------------------------

    In-water construction activities associated with the project would 
include impact pile driving vibratory pile driving. The sounds produced 
by these activities fall into one of two general sound types: pulsed 
and non-pulsed (defined in the following). The distinction between 
these two sound types is important because they have

[[Page 79829]]

differing potential to cause physical effects, particularly with regard 
to hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see 
Southall et al., (2007) for an in-depth discussion of these concepts.
    Pulsed sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986; Harris, 1998; NIOSH, 1998; ISO, 2003; ANSI, 2005) and 
occur either as isolated events or repeated in some succession. Pulsed 
sounds are all characterized by a relatively rapid rise from ambient 
pressure to a maximal pressure value followed by a rapid decay period 
that may include a period of diminishing, oscillating maximal and 
minimal pressures, and generally have an increased capacity to induce 
physical injury as compared with sounds that lack these features.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or non-continuous (ANSI, 1995; 
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, down-the-hole drilling, and active 
sonar systems. The duration of such sounds, as received at a distance, 
can be greatly extended in a highly reverberant environment.
    Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper, 2005). 
Vibratory hammers install piles by vibrating them and allowing the 
weight of the hammer to push them into the sediment. Vibratory hammers 
produce significantly less sound than impact hammers. Peak SPLs may be 
180 dB or greater, but are generally 10 to 20 dB lower than SPLs 
generated during impact pile driving of the same-sized pile (Oestman et 
al., 2009). Rise time is slower, reducing the probability and severity 
of injury, and sound energy is distributed over a greater amount of 
time (Nedwell and Edwards, 2002; Carlson et al., 2005).

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals, 
and exposure to sound can have deleterious effects. To appropriately 
assess these potential effects, it is necessary to understand the 
frequency ranges marine mammals are able to hear. Current data indicate 
that not all marine mammal species have equal hearing capabilities 
(e.g., Richardson et al., 1995; Wartzok and Ketten, 1999; Au and 
Hastings, 2008). To reflect this, Southall et al. (2007) recommended 
that marine mammals be divided into functional hearing groups based on 
measured or estimated hearing ranges on the basis of available 
behavioral data, audiograms derived using auditory evoked potential 
techniques, anatomical modeling, and other data. The lower and/or upper 
frequencies for some of these functional hearing groups have been 
modified from those designated by Southall et al. (2007). The 
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 (mysticetes): functional hearing 
is estimated to occur between approximately 7 Hz and 25 kHz (extended 
from 22 kHz; Watkins, 1986; Au et al., 2006; Lucifredi and Stein, 2007; 
Ketten and Mountain, 2009; Tubelli et al., 2012);
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): functional hearing is estimated to occur 
between approximately 150 Hz and 160 kHz;
     High-frequency cetaceans (porpoises, 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; and
     Pinnipeds in water: functional hearing is estimated to 
occur between approximately 75 Hz to 100 kHz for Phocidae (true seals) 
and between 100 Hz and 48 kHz for Otariidae (eared seals), with the 
greatest sensitivity between approximately 700 Hz and 20 kHz. 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).
    There are two marine mammal species (one otariid pinniped and one 
phocid pinniped) with expected potential to co-occur with UniSea 
construction activities. Please refer to Table 2.

Acoustic Effects, Underwater

    Potential Effects of Pile Driving Sound--The effects of sounds from 
pile driving might result in 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., 2004; Nowacek et al., 2007; Southall et al., 2007). The 
effects of pile driving on marine mammals are dependent on several 
factors, including the size, type, and depth of the animal; the depth, 
intensity, and duration of the pile driving sound; the depth of the 
water column; the substrate of the habitat; the standoff distance 
between the pile and the animal; and the sound propagation properties 
of the environment. 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 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. Shallow environments are typically more structurally 
complex, which leads to rapid sound attenuation. 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 would be 
expected to result from physiological and behavioral responses to both 
the type and strength of the acoustic signature (Viada et al., 2008). 
The type and severity of behavioral impacts are more difficult to 
define due to limited studies addressing the behavioral effects of 
impulsive sounds on marine mammals. Potential effects from impulsive 
sound sources can range in severity from effects such as behavioral 
disturbance or tactile perception to physical discomfort, slight injury 
of the internal organs and the auditory system, or mortality (Yelverton 
et al., 1973).
    Hearing Impairment and Other Physical Effects--Marine mammals

[[Page 79830]]

exposed to high intensity sound repeatedly or 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, 2005). TS can be permanent (PTS), 
in which case the loss of hearing sensitivity is not recoverable, or 
temporary (TTS), in which case the animal's hearing threshold would 
recover over time (Southall et al., 2007). Marine mammals depend on 
acoustic cues for vital biological functions, (e.g., orientation, 
communication, finding prey, avoiding predators); thus, TTS may result 
in reduced fitness in survival and reproduction. However, this depends 
on the frequency and duration of TTS, as well as the biological context 
in which it occurs. TTS of limited duration, occurring in a frequency 
range that does not coincide with that used for recognition of 
important acoustic cues, would have little to no effect on an animal's 
fitness. Repeated sound exposure that leads to TTS could cause PTS. PTS 
constitutes injury, but TTS does not (Southall et al., 2007). The 
following subsections discuss in somewhat more detail the possibilities 
of TTS, PTS, and non-auditory physical effects.
    Temporary Threshold Shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to a strong sound (Kryter, 
1985). While experiencing TTS, the hearing threshold rises, and a sound 
must be stronger in order to be heard. In terrestrial mammals, TTS can 
last from minutes or hours to days (in cases of strong TTS). For sound 
exposures at or somewhat above the TTS threshold, hearing sensitivity 
in both terrestrial and marine mammals 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 
published data concern TTS elicited by exposure to multiple pulses of 
sound. Available data on TTS in marine mammals are summarized in 
Southall et al. (2007).
    Given the available data, the received level of a single pulse 
(with no frequency weighting) might need to be approximately 186 dB re 
1 [mu]Pa\2\-s (i.e., 186 dB sound exposure level [SEL] or approximately 
221-226 dB p-p [peak]) in order to produce brief, mild TTS. Exposure to 
several strong pulses that each have received levels near 190 dB rms 
(175-180 dB SEL) might result in cumulative exposure of approximately 
186 dB SEL and thus slight TTS in a small odontocete, assuming the TTS 
threshold is (to a first approximation) a function of the total 
received pulse energy.
    The above TTS information for odontocetes is derived from studies 
on the bottlenose dolphin (Tursiops truncatus) and beluga whale 
(Delphinapterus leucas). There is no published TTS information for 
other species of cetaceans. However, preliminary evidence from a harbor 
porpoise exposed to pulsed sound suggests that its TTS threshold may 
have been lower (Lucke et al., 2009). As summarized above, data that 
are now available imply that TTS is unlikely to occur unless 
odontocetes are exposed to pile driving pulses stronger than 180 dB re 
1 [mu]Pa rms.
    Permanent Threshold Shift--When PTS occurs, there is physical 
damage to the sound receptors in the ear. In severe cases, there can be 
total or partial deafness, while in other cases the animal has an 
impaired ability to hear sounds in specific frequency ranges (Kryter, 
1985). There is no specific evidence that exposure to pulses of sound 
can cause PTS in any marine mammal. However, given the possibility that 
mammals close to a sound source might incur TTS, there has been further 
speculation about the possibility that some individuals might incur 
PTS. Single or occasional occurrences of mild TTS are not indicative of 
permanent auditory damage, but repeated or (in some cases) single 
exposures to a level well above that causing TTS onset might elicit 
PTS.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals but are assumed to be similar to those in humans and 
other terrestrial mammals. PTS might occur at a received sound level at 
least several decibels above that inducing mild TTS if the animal were 
exposed to strong sound pulses with rapid rise time. Based on data from 
terrestrial mammals, a precautionary assumption is that the PTS 
threshold for impulse sounds (such as pile driving pulses as received 
close to the source) is at least 6 dB higher than the TTS threshold on 
a peak-pressure basis and probably greater than 6 dB (Southall et al., 
2007). On an SEL basis, Southall et al. (2007) estimated that received 
levels would need to exceed the TTS threshold by at least 15 dB for 
there to be risk of PTS. Thus, for cetaceans, Southall et al. (2007) 
estimate that the PTS threshold might be an M-weighted SEL (for the 
sequence of received pulses) of approximately 198 dB re 1 [mu]Pa\2\-s 
(15 dB higher than the TTS threshold for an impulse). Given the higher 
level of sound necessary to cause PTS as compared with TTS, it is 
considerably less likely that PTS could occur.
    Measured source levels from impact pile driving can be as high as 
214 dB rms. Although no marine mammals have been shown to experience 
TTS or PTS as a result of being exposed to pile driving activities, 
captive bottlenose dolphins and beluga whales exhibited changes in 
behavior when exposed to strong pulsed sounds (Finneran et al., 2000, 
2002, 2005). The animals tolerated high received levels of sound before 
exhibiting aversive behaviors. Experiments on a beluga whale showed 
that exposure to a single watergun impulse at a received level of 207 
kPa (30 psi) p-p, which is equivalent to 228 dB p-p, resulted in a 7 
and 6 dB TTS in the beluga whale at 0.4 and 30 kHz, respectively. 
Thresholds returned to within 2 dB of the pre-exposure level within 
four minutes of the exposure (Finneran et al., 2002). Although the 
source level of pile driving from one hammer strike is expected to be 
much lower than the single watergun impulse cited here, animals being 
exposed for a prolonged period to repeated hammer strikes could receive 
more sound exposure in terms of SEL than from the single watergun 
impulse (estimated at 188 dB re 1 [mu]Pa\2\-s) in the aforementioned 
experiment (Finneran et al., 2002). However, in order for marine 
mammals to experience TTS or PTS, the animals have to be close enough 
to be exposed to high intensity sound levels for a prolonged period of 
time. Based on the best scientific information available, these SPLs 
are far below the thresholds that could cause TTS or the onset of PTS.
    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

[[Page 79831]]

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

    Disturbance includes a variety of effects, including subtle changes 
in behavior, more conspicuous changes in activities, and displacement. 
Behavioral responses to sound are highly variable and context-specific 
and reactions, if any, depend on species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day, and many other factors (Richardson et al., 1995; Wartzok 
et al., 2003; Southall et al., 2007).
    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. 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. Behavioral state may affect the type of response as well. 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 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 guns or acoustic harassment devices, but also 
including pile driving) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; Thorson and Reyff, 2006; see also Gordon et al., 2004; 
Wartzok et al., 2003; Nowacek et al., 2007). Responses to continuous 
sound, such as vibratory pile installation, have not been documented as 
well as responses to pulsed sounds.
    With both types of pile driving, it is likely that the onset of 
pile driving could result in temporary, short term changes in an 
animal's typical behavior and/or avoidance of the affected area. These 
behavioral changes may include (Richardson et al., 1995): changing 
durations of surfacing and dives, number of blows per surfacing 
(cetaceans only), 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; 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 the amount of time 
spent hauled out, 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);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     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, or 
interfering with, a marine mammal's ability to hear other sounds. 
Masking occurs when the receipt of a sound is interfered with by 
another coincident sound at similar frequencies and at similar or 
higher levels. Chronic exposure to excessive, though not high-
intensity, sound could cause masking at particular frequencies for 
marine mammals that utilize sound for vital biological functions. 
Masking can interfere with detection of acoustic signals such as 
communication calls, echolocation sounds, and environmental sounds 
important to marine mammals. Therefore, under certain circumstances, 
marine mammals whose acoustical sensors or environment are being 
severely masked could also be impaired from maximizing their 
performance fitness in survival and reproduction. If the coincident 
(masking) sound were man-made, it could be potentially harassing if it 
disrupted hearing-related behavior. 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. Because sound 
generated from in-water pile driving is mostly concentrated at low 
frequency ranges, it may affect detection of communication calls and 
other potentially important natural sounds such as surf and prey sound. 
It may also affect communication signals when they occur near the sound 
band and thus reduce the communication space of animals (e.g., Clark et 
al., 2009) and cause increased stress levels (e.g., Foote et al., 2004; 
Holt et al., 2009).
    Masking has the potential to impact species at the population or 
community levels as well as at individual levels. Masking affects both 
senders and receivers of the signals and can potentially have long-term 
chronic effects on marine mammal species and populations. Recent 
research suggests that 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, and that most of 
these increases are from distant shipping (Hildebrand, 2009). All 
anthropogenic sound sources, such as those from vessel traffic, pile 
driving, and dredging activities, contribute to the elevated ambient 
sound levels, thus intensifying masking.
    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 the proposed action to mask acoustic signals important to the 
behavior and survival of marine mammal species is likely to be 
negligible. 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 the 
proposed action may mask acoustic signals important to the behavior and 
survival

[[Page 79832]]

of marine mammal species, but the short-term duration and limited 
affected area would result in insignificant impacts from masking.

Acoustic Effects, Airborne

    Marine mammals that occur in the project area could be exposed to 
airborne sounds associated with pile driving that have the potential to 
cause harassment, depending on their distance from pile driving 
activities. Airborne sound could potentially affect pinnipeds that are 
either hauled out or are in the water but have their heads above water 
in the project area. 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 their 
habitat and move further from the source. Studies by Blackwell et al. 
(2004) and Moulton et al. (2005) indicate a tolerance or lack of 
response to unweighted airborne sounds as high as 112 dB peak and 96 dB 
rms.

Anticipated Effects on Habitat

    The proposed activities at Iliuliuk Harbor would not result in 
permanent impacts to habitats used directly by marine mammals, such as 
haul-out sites, but may have potential short-term impacts to food 
sources such as forage fish and salmonids. There are no rookeries or 
haulout sites within the modeled zone of influence for impact or 
vibratory pile driving associated with the project, or ocean bottom 
structure of significant biological importance to marine mammals that 
may be present in the waters in the vicinity of the project area. The 
project location is characterized by several commercial fish processing 
facilities and experiences frequent vessel traffic because of these 
facilities, thus the area is already relatively industrialized and not 
a pristine habitat for sea lions or seals. As such, the main impact 
associated with the proposed activity would be temporarily elevated 
sound levels and the associated direct effects on marine mammals, as 
discussed previously in this document. The most likely impact to marine 
mammal habitat occurs from pile driving effects on likely marine mammal 
prey (i.e., fish) near the project location, and minor impacts to the 
immediate substrate during installation and removal of piles during the 
dock construction project.

Effects on Potential Prey

    Construction activities would produce both pulsed (i.e., impact 
pile driving) and continuous (i.e., vibratory pile driving and down-
the-hole drilling) sounds. Fish react to sounds which 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) and are therefore not directly comparable with the 
proposed project. 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. In general, impacts to marine mammal prey species from the 
proposed project are expected to be minor and temporary due to the 
relatively short timeframe of the proposed project, and the fact that 
Iliuliuk Harbor is not considered an important habitat for salmonids. 
The nearby Iliuliuk River supports salmon runs for at least four 
species of salmonids, however the harbor itself does not provide 
significant habitat for salmonids, and the proposed project is located 
far enough away from the lower Iliuliuk River that the potential that 
fish entering or leaving the river will be impacted is considered 
discountable. 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.

Effects on Potential Foraging Habitat

    The area likely impacted by the project is very small relative to 
the available habitat in Unalaska Bay. Avoidance by potential prey 
(i.e., fish) of the immediate area due to the temporary loss of this 
foraging habitat is possible. The duration of fish avoidance of this 
area after pile driving stops is unknown, but a rapid return to normal 
recruitment, distribution and behavior is anticipated. Any behavioral 
avoidance by fish of the disturbed area would still leave significantly 
large areas of fish and marine mammal foraging habitat in Unalaska Bay 
and the nearby vicinity.
    In summary, given the short daily duration of sound associated with 
individual pile driving events and the relatively small area that would 
be affected, pile driving activities associated with the proposed 
action are not likely to have a permanent, adverse effect on any fish 
habitat, or populations of fish species. Thus, any impacts to marine 
mammal habitat are not expected to cause significant or long-term 
consequences for individual marine mammals or their populations.

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 and an 
exclusion zone (see ``Estimated Take by Incidental Harassment''). These 
values were then used to develop mitigation measures for proposed pile 
driving activities. The exclusion zone effectively represents the 
mitigation zone that would be established around each pile to prevent 
Level A harassment to marine mammals, while the zones of influence 
(ZOI) provide estimates of the areas within which Level B harassment 
might occur for impact and vibratory pile driving. While the modeled 
ZOI and exclusion zone vary between the different types of installation 
methods, UniSea is proposing to establish mitigation zones for the 
maximum exclusion zone and ZOI for all pile driving and down-the-hole 
drilling conducted in support of the proposed project.

Monitoring and Shutdown for Pile Driving

    The following measures would apply to UniSea's mitigation through 
the exclusion zone and zone of influence:
    Exclusion Zone--For all pile driving activities, UniSea will 
establish an exclusion zone intended to contain the area in which SPLs 
equal or exceed the 190 dB rms acoustic injury criteria for pinnipeds. 
The purpose of the exclusion zone is to define an area within which 
shutdown of construction activity would occur upon sighting of a marine

[[Page 79833]]

mammal within that area (or in anticipation of an animal entering the 
defined area), thus preventing potential injury of marine mammals. 
Modeled distances to the Level A harassment threshold are shown in 
Table 5. The greatest modeled distance to the Level A harassment 
threshold is 4.64 m (for impact pile driving); however, UniSea would 
implement a minimum 10 m radius exclusion zone for all pile driving and 
down-the-hole drilling activities. See Appendix B in the IHA 
application for figures showing the exclusion zones overlaid on 
satellite images of the project area.
    Zone of Influence--The zone of influence refers to the area(s) in 
which SPLs equal or exceed 160 and 120 dB rms (for pulsed and non-
pulsed continuous sound, respectively). ZOIs provide utility for 
monitoring that is conducted for mitigation purposes (i.e., exclusion 
zone monitoring) by establishing monitoring protocols for areas 
adjacent to the exclusion zone. Monitoring of the ZOI enables observers 
to be aware of, and communicate about, the presence of marine mammals 
within the project area but outside the exclusion zone and thus prepare 
for potential shutdowns of activity should those marine mammals 
approach the exclusion zone. However, the primary purpose of ZOI 
monitoring is to allow documentation of incidents of Level B 
harassment; ZOI monitoring is discussed in greater detail later (see 
``Proposed Monitoring and Reporting''). The modeled radial distances 
for ZOIs for impact and vibratory pile driving and removal (not taking 
into account landmasses which are expected to limit the actual ZOI 
radii) are shown in Table 5.
    In order to document observed incidents of harassment, monitors 
will record all marine mammals observed within the modeled ZOI. 
Modeling was performed to estimate the ZOI for impact pile driving (the 
areas in which SPLs are expected to equal or exceed 160 dB rms during 
impact driving) and for vibratory pile driving (the areas in which SPLs 
are expected to equal or exceed 120 dB rms during vibratory driving and 
removal). Results of this modeling showed the ZOI for impact driving 
would extend to a radius of 500 m from the pile being driven, the ZOI 
for vibratory pile driving and down-the-hole drilling (if it occurs) 
would extend to a radius of 10,000 m from the pile being driven, and 
the ZOI for vibratory pile removal would extend to a radius of 7,400 m 
from the pile being removed. However, due to the geography of the 
project area, landmasses surround Iliuliuk Harbor are expected to limit 
the propagation of sound from construction activities such that the 
actual distances to the ZOI extent for vibratory and impact driving 
will be substantially smaller than those described above. Modeling 
results of the ensonified areas, taking into account the attenuation 
provided by landmasses, suggest the actual ZOI will extend to a maximum 
distance of 1,250 m from the G1 dock, at its furthest point (for 
vibratory driving). Due to this relatively small modeled ZOI, and due 
to the monitoring locations chosen by UniSea (see the Monitoring Plan 
for details), we expect that monitors will be able to observe the 
entire modeled ZOI for both impact and vibratory pile driving, and thus 
we expect data collected on incidents of Level B harassment to be 
relatively accurate. The modeled areas of the ZOIs for impact and 
vibratory driving, taking into account the attenuation provided by 
landmasses in attenuating sound from the construction project, are 
shown in Appendix B of UniSea's application.
    Monitoring Protocols--Monitoring would be conducted before, during, 
and after pile driving activities. Observations of marine mammals 
outside the exclusion zone will not result in shutdown of construction 
operations, unless the animal approaches or enters the exclusion zone, 
at which point all pile driving activities will be halted. Monitoring 
will take place from fifteen minutes prior to initiation of pile 
driving or pile removal through thirty minutes post-completion of pile 
driving or removal activities. Pile driving and removal activities 
include the time to 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 the Marine Mammal Monitoring Plan 
(available at www.nmfs.noaa.gov/pr/permits/incidental/), for full 
details of the monitoring protocols.
    The following additional measures apply to visual monitoring:
    (1) Monitoring will be conducted by qualified observers, who will 
be placed at the best vantage point(s) practicable to monitor for 
marine mammals and implement shutdown procedures when applicable by 
calling for the shutdown to the hammer operator. Qualified observers 
are trained biologists, with the following minimum qualifications:
     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;
     Experience and ability to conduct field observations and 
collect data according to assigned protocols;
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors, with ability 
to accurately identify marine mammals in Alaskan waters to species;
     Sufficient training, orientation or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations; and
     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.
    (2) Prior to the start of pile driving activity, the exclusion zone 
will be monitored for fifteen minutes to ensure that it is clear of 
marine mammals. Pile driving will only commence once observers have 
declared the exclusion zone clear of marine mammals; animals will be 
allowed to remain in the exclusion zone (i.e., must leave of their own 
volition) and their behavior will be monitored and documented. The 
exclusion zone may only be declared clear, and pile driving started, 
when the entire exclusion 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 exclusion 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 exclusion zone or fifteen minutes have 
passed without re-detection of the animal. Monitoring will be conducted 
throughout the time required to drive a pile.

Sound Attenuation Devices

    Sound levels can be 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. UniSea plans to use bubble curtains, which 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

[[Page 79834]]

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). Confined bubble curtain contain the air bubbles within a 
flexible or rigid sleeve made from plastic, cloth, or pipe, and 
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).
    The literature presents a wide array of observed attenuation 
results for bubble curtains (e.g., Oestman et al., 2009; Coleman, 
2011). Both environmental conditions and the characteristics of the 
sound attenuation device may influence the effectiveness of the device 
(Oestman et al. 2009). As a general rule, reductions of greater than 10 
dB cannot be reliably predicted. The U.S. Navy Test Pile Program, 
conducted at Naval Base Kitsap-Bangor, reported a range of measured 
values for realized attenuation mostly within 6 to 12 dB (Illingworth & 
Rodkin, 2012).
    Unconfined bubble curtains will be used during all impact pile 
driving associated with the proposed project. The bubble curtain used 
by UniSea may result in some noise reduction from impact pile driving; 
however, we are unable make any assumptions about the extent of the 
attenuation that may be provided by UniSea's bubble curtain, as sound 
source verification at pile driving projects using the proposed bubble 
curtain design has not occurred previously, and in situ recordings are 
not proposed for this particular project.

Soft Start

    The use of a ``soft-start'' procedure is believed to provide 
additional protection to marine mammals by providing a warning and an 
opportunity to leave the area prior to the hammer operating at full 
capacity. For vibratory hammers, the soft start technique will initiate 
noise from the hammer for 15 seconds at a reduced energy level, 
followed by 1- minute waiting period and repeat the procedure two 
additional times. For impact hammers, the soft start technique will 
initiate three strikes at a reduced energy level, followed by a 30-
second waiting period. This procedure would also be repeated two 
additional times. 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.'' Soft start for impact driving will be required at 
the beginning of each day's pile driving work and at any time following 
a cessation of impact pile driving of thirty minutes or longer.
    We have carefully evaluated UniSea's proposed mitigation measures 
and considered their likely effectiveness relative to implementation of 
similar mitigation measures in previously issued IHAs to preliminarily 
determine whether they are likely to affect 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) we prescribe should be able to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to the accomplishment of one or more of 
the general goals listed below:
    (1) Avoidance or minimization of injury or death of marine mammals 
wherever possible (goals 2, 3, and 4 may contribute to this goal).
    (2) A reduction in the number (total number or number at 
biologically important time or location) of individual marine mammals 
exposed to stimuli expected to result in incidental take (this goal may 
contribute to 1, above, or to reducing takes by behavioral harassment 
only).
    (3) A reduction in the number (total number or number at 
biologically important time or location) of times any individual marine 
mammal would be exposed to stimuli expected to result in incidental 
take (this goal may contribute to 1, above, or to reducing takes by 
behavioral harassment only).
    (4) A reduction in the intensity of exposure to stimuli expected to 
result in incidental take (this goal may contribute to 1, above, or to 
reducing the severity of behavioral harassment only).
    (5) Avoidance or minimization of adverse effects to marine mammal 
habitat, paying particular attention to the prey base, blockage or 
limitation of passage to or from biologically important areas, 
permanent destruction of habitat, or temporary disturbance of habitat 
during a biologically important time.
    (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 UniSea's proposed measures, we have 
preliminarily determined that the proposed mitigation measures provide 
the means of affecting the least practicable impact on marine mammal 
species or stocks and their habitat.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking.'' The MMPA implementing 
regulations at 50 CFR 216.104(a)(13) indicate that requests for 
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 accomplish one or 
more of the following general goals:
    1. An increase in the probability of detecting marine mammals, both 
within defined zones of effect (thus allowing for more effective 
implementation of the mitigation) and in general to generate more data 
to contribute to the analyses mentioned below;
    2. An increase in our understanding of how many marine mammals are 
likely to be exposed to stimuli that we associate with specific adverse 
effects, such as behavioral harassment or hearing threshold shifts;
    3. An increase in our understanding of how marine mammals respond 
to stimuli expected to result in incidental take and how anticipated 
adverse effects on individuals may impact the population, stock, or 
species (specifically through effects on annual rates of recruitment or 
survival) through any of the following methods:
     Behavioral observations in the presence of stimuli 
compared to observations in the absence of stimuli (need to be able to 
accurately predict pertinent information, e.g., received level, 
distance from source);
     Physiological measurements in the presence of stimuli 
compared to observations in the absence of stimuli (need to be able to 
accurately predict

[[Page 79835]]

pertinent information, e.g., received level, distance from source); and
     Distribution and/or abundance comparisons in times or 
areas with concentrated stimuli versus times or areas without stimuli.
    4. An increased knowledge of the affected species; or
    5. An increase in our understanding of the effectiveness of certain 
mitigation and monitoring measures.
    UniSea submitted a marine mammal monitoring plan as part of their 
IHA application (the monitoring plan can be viewed online at: 
www.nmfs.noaa.gov/pr/permits/incidental/). UniSea's proposed marine 
mammal monitoring plan was created with input from NMFS and was based 
on similar plans that have been successfully implemented by other 
action proponents under previous IHAs for pile driving projects. 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 Observations

    UniSea will collect sighting data and will record behavioral 
responses to construction activities for marine mammal species observed 
in the project location during the period of activity. All marine 
mammal observers (MMOs) will be trained in marine mammal identification 
and behaviors and are required to have no other construction-related 
tasks while conducting monitoring. UniSea will monitor the Exclusion 
Zone and Zone of Influence before, during, and after pile driving, with 
observers located at the best practicable vantage points. See Figure 2 
in the Marine Mammal Monitoring Plan for the observer locations planned 
for use during construction. Based on our requirements, the Marine 
Mammal Monitoring Plan would implement the following procedures for 
pile driving:
     A dedicated monitoring coordinator will be on-site during 
all construction days. The monitoring coordinator will oversee marine 
mammal observers. The monitoring coordinator will serve as the liaison 
between the marine mammal monitoring staff and the construction 
contractor to assist in the distribution of information.
     MMOs would be located at the best vantage point(s) in 
order to properly observe the entire Exclusion Zone, and as much of the 
ZOI as possible. A minimum of two MMOs will be on duty during all pile 
driving activity, with one of these MMOs having full time 
responsibility for monitoring the Exclusion Zone.
     During all observation periods, observers will use 
binoculars and the naked eye to search continuously for marine mammals.
     If the Exclusion Zone is obscured by fog or poor lighting 
conditions, pile driving will not be initiated until the Exclusion Zone 
is clearly visible. Should such conditions arise while impact driving 
is underway, the activity would be halted.
     The Exclusion Zone and ZOI will be monitored for the 
presence of marine mammals before, during, and after any pile driving 
or removal activity.
    Individuals implementing the monitoring protocol will assess its 
effectiveness using an adaptive approach. MMOs will use their best 
professional judgment throughout implementation and seek improvements 
to these methods when deemed appropriate. Any modifications to protocol 
will be coordinated between NMFS and UniSea.

Data Collection

    We require that observers use approved data forms. Among other 
pieces of information, UniSea will record detailed information about 
any implementation of shutdowns, including the distance of animals to 
the pile being driven, a description of specific actions that ensued, 
and resulting behavior of the animal, if any. In addition, UniSea will 
attempt to distinguish between the number of individual animals taken 
and the number of incidents of take, when possible. We require that, at 
a minimum, the following information be collected on 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 marine mammal(s) to the observation point;
     Locations of all marine mammal observations; and
     Other human activity in the area.

Reporting

    A draft report will be submitted within 90 calendar days of the 
completion of the activity, or within 45 calendar days prior to the 
effective date of a subsequent IHA (if applicable). The report will 
include information on marine mammal observations pre-activity, during-
activity, and post-activity during pile driving days, and will provide 
descriptions of any behavioral responses to construction activities by 
marine mammals and a complete description of any mitigation shutdowns 
and results of those actions, as well as an estimate of total take 
based on the number of marine mammals observed during the course of 
construction. A final report must be submitted within 30 days following 
resolution of comments from NMFS on the draft report.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner not authorized by the 
IHA (if issued), such as a Level A harassment, or a take of a marine 
mammal species other than those proposed for authorization, UniSea 
would immediately cease the specified activities and immediately report 
the incident to the Chief of the Permits and Conservation Division, 
Office of Protected Resources. The report would include the following 
information:
     Time, date, and location (latitude/longitude) of the 
incident;
     Description of the incident;
     Status of all sound source use in the 24 hours preceding 
the incident;
     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 UniSea to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. UniSea would not be able to 
resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that UniSea 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), UniSea would immediately report the 
incident tomailto: 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

[[Page 79836]]

above. Construction related activities would be able to continue while 
NMFS reviews the circumstances of the incident. NMFS would work with 
UniSea to determine whether modifications in the activities are 
appropriate.
    In the event that UniSea 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), UniSea would report the incident 
to Jolie Harrison (Jolie.Harrison@noaa.gov), Chief of the Permits and 
Conservation Division, Office of Protected Resources, NMFS, and Aleria 
Jensen (Aleria.Jensen@noaa.gov), Alaska Stranding Coordinator, within 
24 hours of the discovery. UniSea 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 and impact pile driving and involving temporary changes 
in behavior. Based on the best available information, the proposed 
activities--vibratory and impact pile driving--would not result in 
serious injuries or mortalities to marine mammals even in the absence 
of the planned mitigation and monitoring measures. However, the 
proposed mitigation and monitoring measures are expected to minimize 
the potential for injury, such that take by Level A harassment is 
considered discountable.
    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 or 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.
    This practice potentially overestimates the numbers of marine 
mammals taken, as it is often difficult to distinguish between the 
individual animals harassed and incidences of harassment. 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. The Steller sea lions and harbor 
seals expected to occur in the project area are not branded, thus we 
expect that the identification of individual animals, even by 
experienced MMOs, would be extremely difficult. This would further 
increase the likelihood that repeated exposures of an individual, even 
within the same day, could be recorded as multiple takes.
    UniSea has requested authorization for the incidental taking of 
small numbers of Steller sea lions and harbor seals that may result 
from pile driving activities associated with the dock construction 
project described previously in this document. 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 incorporate 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 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. To date, no studies 
have been conducted that explicitly examine impacts to marine mammals 
from pile driving sounds or from which empirical sound thresholds have 
been established. These thresholds should be considered guidelines for 
estimating 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 currently revising these acoustic 
guidelines; for more information on that process, please see: 
www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

            Table 4--Current NMFS Acoustic Exposure Criteria
------------------------------------------------------------------------
            Criterion                 Definition           Threshold
------------------------------------------------------------------------
Level A harassment (underwater).  Injury (PTS--any    180 dB (cetaceans)/
                                   level above that    190 dB
                                   which is known to   (pinnipeds)
                                   cause TTS).         (rms).
Level B harassment (underwater).  Behavioral          160 dB (impulsive
                                   disruption.         source\*\)/120 dB
                                                       (continuous
                                                       source\*\) (rms).
Level B harassment                Behavioral          90 dB (harbor
 (airborne)\**\.                   disruption.         seals)/100 dB
                                                       (other pinnipeds)
                                                       (unweighted).
------------------------------------------------------------------------
\*\ Impact pile driving produces impulsive noise; vibratory pile driving
  produces non-pulsed (continuous) noise.
\**\ NMFS has not established any formal criteria for harassment
  resulting from exposure to airborne sound. However, these thresholds
  represent the best available information regarding the effects of
  pinniped exposure to such sound and NMFS' practice is to associate
  exposure at these levels with Level B harassment.


[[Page 79837]]

Distance to Sound Thresholds

    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 * log10(R1/R2), where
R1 = the distance of the modeled SPL from the driven 
pile, and
R2 = the distance from the driven pile of the initial 
measurement

    This formula neglects loss due to scattering and absorption, which 
is assumed to be zero here. The degree to which underwater sound 
propagates away from a sound source is dependent on a variety of 
factors, most notably the water bathymetry and presence or absence of 
reflective or absorptive conditions including in-water structures and 
sediments. Spherical spreading occurs in a perfectly unobstructed 
(free-field) environment not limited by depth or water surface, 
resulting in a 6 dB reduction in sound level for each doubling of 
distance from the source (20*log[range]). Cylindrical spreading occurs 
in an environment in which sound propagation is bounded by the water 
surface and sea bottom, resulting in a reduction of 3 dB in sound level 
for each doubling of distance from the source (10*log[range]). A 
practical spreading value of fifteen is often used under conditions, 
such as Iliuliuk Harbor, where water depth increases as the receiver 
moves away from the shoreline, resulting in an expected propagation 
environment that would lie between spherical and cylindrical spreading 
loss conditions. Practical spreading loss (4.5 dB reduction in sound 
level for each doubling of distance) is assumed here.
    Underwater Sound--The intensity of pile driving sounds is greatly 
influenced by factors such as the type of piles, hammers, and the 
physical environment in which the activity occurs. A large quantity of 
literature regarding SPLs recorded from pile driving projects is 
available for consideration. In order to determine reasonable SPLs and 
their associated effects on marine mammals that are likely to result 
from pile driving at the UniSea dock, studies with similar properties 
to the specified activity were evaluated. See Section 5 of UniSea's 
application for a detailed description of the information considered in 
determining reasonable proxy source level values. UniSea used 
representative source levels of 165 dB rms for installation of steel 
sheet piles using a vibratory hammer (CALTRANS 2012), 163 dB rms for 
vibratory removal and installation of a 24-inch steel pile (Rodkin 
2013), 184 dB rms for impact pile driving of a 24-inch steel pile 
(Rodkin 2013), and 165 dB (re: 1 [mu]Pa at 1m) at 200 Hz for down-the-
hole drilling (URS 2011).

   Table 5--Modeled Distances From G1 Dock to NMFS Level A and Level B
 Harassment Thresholds (Isopleths) During Pile Installation and Removal
------------------------------------------------------------------------
                  Threshold                      Distance (meters)\*\
------------------------------------------------------------------------
Impact driving, pinniped injury (190 dB)....  4.64\**\
Impact driving, pinniped disturbance (160     500
 dB).
Vibratory driving, pinniped injury (190 dB).  < 1 m\**\
Vibratory driving or down-the-hole drilling,  10,000
 pinniped disturbance (120 dB).
Vibratory removal, pinniped injury (160 dB).  < 1 m\**\
Vibratory removal, pinniped disturbance (120  7,400
 dB).
------------------------------------------------------------------------
\*\ Distances shown are modeled maximum distances and do not account for
  landmasses which are expected to reduce the actual distances to sound
  thresholds.
\**\ These are modeled distances to the Level A harassment threshold,
  however the exclusion zone will conservatively extend to 10 m, thus
  any marine mammal within a 10 m radius of activity would trigger a
  shutdown.

    Iliuliuk Harbor does not represent open water, or free field, 
conditions. Therefore, sounds would attenuate as they encounter land 
masses. As a result, and as described above, pile driving noise in the 
project area is not expected to propagate to the calculated distances 
for the 160 dB or 120 dB thresholds as shown in Table 5. See Appendix B 
of UniSea's IHA application for figures depicting the actual extents of 
areas in which each underwater sound threshold is predicted to occur at 
the project area due to pile driving, taking into account the 
attenuation provided by landmasses.
    Airborne Sound--Pile driving can generate airborne sound that could 
potentially result in disturbance to pinnipeds that are hauled out or 
at the water's surface. As a result, UniSea analyzed the potential for 
pinnipeds hauled out or swimming at the surface near the G1 dock to be 
exposed to airborne SPLs that could result in Level B behavioral 
harassment. A spherical spreading loss model (i.e., 6 dB reduction in 
sound level for each doubling of distance from the source), in which 
there is a perfectly unobstructed (free-field) environment not limited 
by depth or water surface, is appropriate for use with airborne sound 
and was used to estimate the distance to the airborne thresholds.
    As discussed above regarding underwater sound from pile driving, 
the intensity of pile driving sounds is greatly influenced by factors 
such as the type of piles, hammers, and the physical environment in 
which the activity occurs. In order to determine reasonable airborne 
SPLs and their associated effects on marine mammals that are likely to 
result from pile driving at Iliuliuk Harbor, studies with similar 
properties to the proposed action, as described previously, were 
evaluated. UniSea used representative source levels of 100 dB Leq/rms 
at 22 m for vibratory removal and installation of a 24-inch steel pile 
and 100 dB Leq/rms at 26 m for impact driven 24-inch steel piles. 
Please see Section 5 of UniSea's application for details of the 
information considered. These values result in a disturbance zone 
(radial distance) of 3.16 m for harbor seals and 1.0 m for Steller sea 
lions. No data was found for the airborne sound levels expected from 
the installation of steel sheet piles or 18-inch steel piles, but sound 
levels from the installation of steel sheet piles and 18-inch steel 
piles are likely to be within a similar range as sound levels mentioned 
above.
    Despite the modeled distances described above, no incidents of 
incidental take resulting solely from airborne sound are likely, as 
distances to the harassment thresholds would not reach areas where 
pinnipeds are known to haul out in the area of the project. Harbor seal 
haulout locations may change slightly depending on weather patterns, 
human disturbance, or prey availability, but the closest known harbor 
seal haulout to the project location is on the north side of Hog 
island, located west of Amaknak Island in Unalaska Bay, approximately 3 
km from the G1 dock (pers. comm., L. Fritz, NMML, to J. Carduner, NMFS, 
Oct 30, 2015). Steller sea lions have greater site fidelity than harbor 
seals; the closest known Steller sea lion haulout is at Priest Rock, a 
point that juts into the Bering Sea on the northeastern corner of 
Unalaska Bay, approximately 20 km from the project site (pers. comm., 
L. Fritz, NMML, to J. Carduner, NMFS, Oct 30, 2015).
    We recognize that pinnipeds in the water could be exposed to 
airborne

[[Page 79838]]

sound that may result in behavioral harassment when their heads are 
above the water's surface. 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.

Marine Mammal Occurrence

    The most appropriate information available was used to estimate the 
number of potential incidences of take. Density estimates for Steller 
sea lions and harbor seals in Iliuliuk Harbor, and more broadly in the 
waters surrounding Unalaska Island, are not readily available. 
Likewise, we were not able to find any published literature or reports 
describing densities or estimating abundance of either species in the 
project area. As such, data collected from marine mammal surveys 
represent the best available information on the occurrence of both 
species in the project area.
    Beginning in April 2015, UniSea personnel began conducting marine 
mammal surveys of Iliuliuk Harbor under the direction of an ecological 
consultant. Observers recorded data on all marine mammals that were 
observed, including Steller sea lions, whales, and harbor seals. Both 
stationary and roving observations occurred within a 1,000 m radius of 
the project site (see Figure 9 in the IHA application for a depiction 
of survey points and marine mammal observations). A combination of two 
of the stationary observation points were surveyed each day, for a 
total of 15 minutes at each point, and the roving route was checked 
once per day over a time span of 15 minutes, covering areas between the 
docks that were too difficult to see from the stationary points. The 
survey recorded the number of animals observed, the species, their 
primary activity, and any additional notes. From January through 
October 2015, a total of 323 Steller sea lions and 33 harbor seals were 
observed during 1,432 separate observations over the course of 358 
hours of surveys. These surveys represent the most recent data on 
marine mammal occurrence in the harbor, and represent the only targeted 
marine mammal surveys of the project area that we are aware of.
    Data from bird surveys of Iliuliuk Harbor conducted by the U.S. 
Army Corps of Engineers (USACE) from 2001-2007, which included 
observations of marine mammals in the harbor, were also available; 
however, we determined that these data were unreliable as a basis for 
prediction of marine mammal abundance in the project location as the 
goal of the USACE surveys was to develop a snapshot of waterfowl and 
seabird location and abundance in the harbor, thus the surveys would 
have been designed and carried out differently if the goal had been to 
document marine mammal use of the harbor (pers. comm., C. Hoffman, 
USACE, to J. Carduner, NMFS, October 26, 2015). Additionally, USACE 
surveys occurred only in winter; as Steller sea lion abundance is 
expected to vary significantly between the breeding and the non-
breeding season in the project location, data that were collected only 
during the non-breeding season have limited utility in predicting year-
round abundance. As such, we determined that the data from the surveys 
commissioned by UniSea in 2015 represents the best available 
information on marine mammals in the project location.

Description of Take Calculation

    The take calculations presented here rely on the best data 
currently available for marine mammal populations in the project 
location. Density data for marine mammal species in the project 
location is not available. Therefore the data collected from marine 
mammal surveys of Iliuliuk Harbor in 2015 represent the best available 
information on marine mammal populations in the project location, and 
this data was used to estimate take. As such, the zones that have been 
calculated to contain the areas ensonified to the Level A and Level B 
thresholds for pinnipeds have been calculated for mitigation and 
monitoring purposes and were not used in the calculation of take. See 
Table 6 for total estimated incidents of take. Estimates were based on 
the following assumptions:
     All marine mammals estimated to be in areas ensonified by 
noise exceeding the Level B harassment threshold for impact and 
vibratory driving (as shown in Appendix B of the IHA application) are 
assumed to be in the water 100% of the time. This assumption is based 
on the fact that there are no haulouts or rookeries within the area 
predicted to be ensonified to the Level B harassment threshold based on 
modeling.
     Predicted exposures were based on total estimated total 
duration of pile driving/removal hours, which are estimated at 1,080 
hours over the entire project. This estimate is based on a 180 day 
project time frame, an average work day of 12 hours (work days may be 
longer than 12 hours in summer and shorter than 12 hours in winter), 
and an estimate that approximately 50% of time during those work days 
will include pile driving and removal activities (with the other 50% of 
work days spent on non-pile driving activities which will not result in 
marine mammal take, such as installing templating and bracing, moving 
equipment, etc.).
     Vibratory or impact driving could occur at any time during 
the ``duration'' and our approach to take calculation assumes a rate of 
occurrence that is the same for any of the calculated zones.
     The hourly marine mammal observation rate recorded during 
marine mammal surveys of Iliuliuk Harbor in 2015 is reflective of the 
hourly rate that will be observed during the construction project.
     Takes were calculated based on estimated rates of 
occurrence for each species in the project area and this rate was 
assumed to be the same regardless of the size of the zone (for impact 
or vibratory driving/removal).
     Activities that may be accomplished by either impact 
driving or down-the-hole drilling (i.e. fender support/pin piles, 
miscellaneous support piles, and temporary support piles) were assumed 
to be accomplished via impact driving. If any of these activities are 
ultimately accomplished via down-the-hole drilling instead of impact 
driving, this would not result in a change in the amount of overall 
effort (as they will be accomplished via down-the-hole drilling instead 
of, and not in addition to, impact driving). As take estimates are 
calculated based on effort and not marine mammal densities, this would 
not change the take estimate.
    Take estimates for Steller sea lions and harbor seals were 
calculated using the following series of steps:
    1. The average hourly rate of animals observed during 2015 marine 
mammal surveys of Iliuliuk Harbor was calculated separately for both 
species (``Observation Rate''). Thus ``Observation Rate'' (OR) = No. of 
individuals observed/hours of observation;
    2. The 95% confidence interval was calculated for the data set, and 
the upper bound of the 95% confidence interval was added to the 
Observation Rate to account for variability of the

[[Page 79839]]

small data set (``Exposure Rate''). Thus ``Exposure Rate'' (XR) = 
[micro]OR + CI95 (where [micro]OR = 
average of monthly observation rates and CI95 = 95% 
confidence interval (normal distribution);
    3. The total estimated hours of pile driving work over the entire 
project was calculated, as described above (``Duration''); Thus 
``Duration'' = total number of work days (180) * average work hours per 
day (12) * percentage of pile driving time during work days (0.5) = 
total work hours for the project (1,080); and
    4. The estimated number of exposures was calculated by multiplying 
the ``Duration'' by the estimated ``Exposure Rate'' for each species. 
Thus, estimated takes = Duration * XR.
    Please refer to Appendix G of the IHA application for a more 
thorough description of the statistical analysis of the observation 
data from marine mammal surveys.
    Steller Sea Lion--Steller sea lion density data for the project 
area is not available. Steller sea lions occur year-round in the 
Aleutian Islands and within Unalaska Bay and Iliuliuk Harbor. As 
described above, local abundance in the non-breeding season (winter 
months) is generally lower overall; data from surveys conducted by 
UniSea in 2015 revealed Steller sea lions were present in Iliuliuk 
Harbor in all months that surveys occurred. We assume, based on marine 
mammal surveys of Iliuliuk Harbor, and based on the best available 
information on seasonal abundance patterns of the species including 
over 20 years of NMML survey data collected in Unalaska, that Steller 
sea lions will be regularly observed in the project area during all 
months of construction. As described above, all Steller sea lions in 
the project area at a given time are assumed to be in the water, thus 
any sea lion within the modeled area of ensonification exceeding the 
Level B harassment threshold would be recorded as taken by Level B 
harassment.
    Estimated take of Steller sea lions was calculated using the 
equations described above, as follows:

[mu]OR = 1.219 individuals/hr
CI95 = 0.798
XR = 2.016
Estimated exposures (Level B harassment) = 2.016 * 1,080 = 2,177

    Thus we estimate that a total of 2,177 Steller sea lion takes will 
occur as a result of the proposed UniSea G1 dock construction project.
    Harbor Seal--Harbor seal density data for the project location is 
not available. We assume, based on the best on the best available 
information, that harbor seals will be encountered in low numbers 
throughout the duration of the project. We relied on the best available 
information to estimate take of harbor seals, which in this case was 
survey data collected from the 2015 marine mammal surveys of Iliuliuk 
Harbor as described above. That survey data showed harbor seals are 
present in the harbor only occasionally, with only 33 seals observed 
over the entire survey. NMML surveys have not been performed in 
Iliuliuk Harbor, but the most recent NMML surveys of Unalaska Bay 
confirm that harbor seals are present in the area in relatively small 
numbers, with the most recent haulout counts in Unalaska Bay (2008-11) 
recording no more than 19 individuals at the three known haulouts 
there. NMML surveys have been limited to the months of July and August, 
so it is not known whether harbor seal abundance in the project area 
varies seasonally. The 2015 marine mammal surveys of Iliuliuk Harbor 
showed numbers of harbor seals in the harbor increasing from July 
through October, but the sample size for those months was extremely 
small (n=30). As described above, all harbor seals in the project area 
at a given time are assumed to be in the water, thus any harbor seals 
within the modeled area of ensonification exceeding the Level B 
harassment threshold would be recorded as taken by Level B harassment.
    Estimated take of harbor seals was calculated using the equations 
described above, as follows:

[mu]OR = 0.171 individuals/hr
CI95 = 0.185
XR = 0.356
Estimated exposures (Level B harassment) = 0.356 * 1,080 hours = 385

    Thus we estimate that a total of 385 harbor seal takes will occur 
as a result of the proposed UniSea G1 dock construction project (Table 
6).
    We therefore propose to authorize the take, by Level B harassment 
only, of a total of 2,177 Steller sea lions (western DPS) and 385 
harbor seals (Aleutian Islands stock) as a result of the proposed 
construction project. These take estimates are considered reasonable 
estimates of the number of marine mammal exposures to sound above the 
Level B harassment threshold that are likely to occur over the course 
of the project, and not the number of individual animals exposed. For 
instance, for pinnipeds that associate fishing boats in Iliuliuk Harbor 
with reliable sources of food, there will almost certainly be some 
overlap in individuals present day-to-day depending on the number of 
vessels entering the harbor, however each instance of exposure for 
these individuals will be recorded as a separate, additional take. 
Moreover, because we anticipate that marine mammal observers will 
typically be unable to determine from field observations whether the 
same or different individuals are being exposed over the course of a 
workday, each observation of a marine mammal will be recorded as a new 
take, although an individual theoretically would only be considered as 
taken once in a given day.

 Table 6--Number of Potential Incidental Takes of Marine Mammals, and Percentage of Stock Abundance, as a Result
                                             of the Proposed Project
----------------------------------------------------------------------------------------------------------------
                                                                          Underwater \1\
                                                                 --------------------------------  Percentage of
                             Species                                               Level B (120        stock
                                                                      Level A           dB)          abundance
----------------------------------------------------------------------------------------------------------------
Steller sea lion................................................               0           2,177               4
Harbor seal.....................................................               0             385              11
----------------------------------------------------------------------------------------------------------------
\1\ We assume, for reasons described earlier, that no takes would occur as a result of airborne noise.


[[Page 79840]]

Analyses and Preliminary Determinations

Negligible Impact Analysis

    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.
    Pile driving activities associated with the proposed dock 
construction project, as outlined previously, have the potential to 
disturb or displace marine mammals. Specifically, the specified 
activities may result in take, in the form of Level B harassment 
(behavioral disturbance) only, from underwater sounds generated from 
pile driving. Potential takes could occur if marine mammals are present 
in the ZOI when pile driving is happening, which is likely to occur 
because: (1) Steller sea lions have established haulouts near Iliuliuk 
Harbor and are frequently observed in Iliuliuk Harbor, in varying 
numbers depending on season and prey availability, and probably 
associate fishing boats entering the harbor with reliable food sources; 
and (2) harbor seals are observed in Iliuliuk Harbor occasionally and 
are known to haulout at sites outside the harbor, including one site 
approximately 3 km from the project location.
    No serious injury or mortality of marine mammals would be 
anticipated as a result of vibratory and impact pile driving, 
regardless of mitigation and monitoring measures. Vibratory hammers do 
not have significant potential to cause injury to marine mammals due to 
the relatively low source levels produced (less than 180 dB rms) and 
the lack of potentially injurious source characteristics. Impact pile 
driving produces short, sharp pulses with higher peak levels than 
vibratory driving and much sharper rise time to reach those peaks. The 
potential for injury that may otherwise result from exposure to noise 
associated with impact pile driving will effectively be minimized 
through the implementation of the planned mitigation measures. These 
measures include: the implementation of a exclusion zone, which is 
expected to eliminate the likelihood of marine mammal exposure to noise 
at received levels that could result in injury; the use of ``soft 
start'' before pile driving, which is expected to provide marine 
mammals near or within the zone of potential injury with sufficient 
time to vacate the area; and the use of a sound attenuation system 
which is expected to dampen the sharp, potentially injurious peaks 
associated with impact driving and to reduce the overall source level 
to some extent (it is difficult to predict the extent of attenuation 
provided as underwater recordings have not been performed for the type 
of bubble curtain proposed for use). We believe the required mitigation 
measures, which have been successfully implemented in similar pile 
driving projects, will minimize the possibility of injury that may 
otherwise exist as a result of impact pile driving.
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from similar 
pile driving projects that have received incidental take authorizations 
from NMFS, will likely be limited to reactions such as increased 
swimming speeds, increased surfacing time, or decreased foraging. Most 
likely, individuals will simply move away from the sound source and be 
temporarily displaced from the area of pile driving (though even this 
reaction has been observed primarily in association with impact pile 
driving). In response to vibratory driving, harbor seals have been 
observed to orient towards and sometimes move towards the sound. 
Repeated exposures of individuals to levels of sound that may cause 
Level B harassment are unlikely to result in hearing impairment or to 
significantly disrupt foraging behavior. 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 to those 
individuals, and thus would not result in any adverse impact to the 
stock as a whole. Level B harassment will be reduced to the level of 
least practicable impact through use of mitigation measures described 
herein and, if sound produced by project activities is sufficiently 
disturbing, animals are likely to simply avoid the project area while 
the activity is occurring.
    No pinniped rookeries or haul-outs are present within the project 
area, and the project area is not known to provide foraging habitat of 
any special importance to either Steller sea lions or harbor seals 
(other than is afforded by the migration of salmonids to and from 
Iliuliuk Stream and the occasional availability of discarded fish from 
commercial fishing boats and fish processing facilities in the project 
area). No cetaceans are expected within the project area. While we are 
not aware of comparable construction projects in the project location, 
the pile driving activities analyzed here are similar to other in-water 
construction activities that have received incidental harassment 
authorizations previously, including projects at Naval Base Kitsap 
Bangor in Hood Canal, Washington, and at the Port of Friday Harbor in 
the San Juan Islands, which have occurred with no reported injuries or 
mortalities to marine mammals, and no known long-term adverse 
consequences to marine mammals from behavioral harassment.
    In summary, this negligible impact analysis is founded on the 
following factors: (1) The possibility of injury, serious injury, or 
mortality may reasonably be considered discountable; (2) the 
anticipated incidences of Level B harassment consist of, at worst, 
temporary modifications in behavior; (3) the absence of any major 
rookeries and only a few isolated haulout areas near the project site; 
(4) the absence of any other known areas or features of special 
significance for foraging or reproduction within the project area; and 
(5) the presumed efficacy of planned 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 individual animals. The specified activity is not 
expected to impact 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, we 
preliminarily find that the total marine mammal take from UniSea's dock 
construction activities in Iliuliuk Harbor will have a negligible 
impact on the affected marine mammal species or stocks.

[[Page 79841]]

Small Numbers Analysis

    The numbers of animals authorized to be taken would be considered 
small relative to the relevant stocks or populations (4 percent and 11 
percent for Steller sea lions and harbor seals, respectively) even if 
each estimated taking occurred to a new individual. However, the 
likelihood that each take would occur to a new individual is extremely 
low. As described above, for those sea lions that associate fishing 
boats with reliable sources of food, there will almost certainly be 
some overlap in individuals present day-to-day depending on the number 
of vessels entering the harbor. It is expected that operations at a 
separate, nearby UniSea dock and the associated UniSea processing 
facilities, as well as at seafood processing facilities owned by other 
companies based in Iliuliuk Harbor, will continue as usual during 
construction on the G1 dock, so it is likely that sea lions accustomed 
to seeking food at these facilities will continue to be attracted to 
the area during portions of the construction activities.
    Further, these takes are likely to occur only within some small 
portion of the overall regional stock. For example, of the estimated 
55,422 western DPS Steller sea lions throughout Alaska, there are 
probably no more than 300 individuals with site fidelity to the three 
haulouts located nearest to the project location, based on over twenty 
years of NMML survey data (see ``Description of Marine Mammals in the 
Area of the Specified Activity'' above). For harbor seals, NMML survey 
data suggest there are likely no more than 60 individuals that use the 
three haulouts nearest to the project location (the only haulouts in 
Unalaska Bay). Thus the estimate of take is an estimate of the number 
of anticipated exposures, rather than an estimate of the number of 
individuals that will be taken, as we expect the majority of exposures 
would be repeat exposures that would accrue to the same individuals. As 
such, the authorized takes would represent a much smaller number of 
individuals of both Steller sea lions and harbor seals, in relation to 
total stock sizes.
    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, we preliminarily find 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

    Subsistence hunting and fishing is an important part of the history 
and culture of Unalaska Island. However, the number of Steller sea 
lions and harbor seals harvested in Unalaska decreased from 1994 
through 2008; in 2008, the last year for which data is available, there 
were no Steller sea lions or harbor seals reported as harvested for 
subsistence use. Data on pinnipeds hunted for subsistence use in 
Unalaska has not been collected since 2008. For a summary of data on 
pinniped harvests in Unalaska from 1994-2008, see Section 8 of the IHA 
application.
    Aside from the apparently decreasing rate of subsistence hunting in 
Unalaska, Iliuliuk Harbor is not likely to be used for subsistence 
hunting or fishing due to its industrial nature, with several fish 
processing facilities located along the shoreline of the harbor. In 
addition, the proposed construction project is likely to result only in 
short-term, temporary impacts to pinnipeds in the form of possible 
behavior changes, and is not expected to result in the injury or death 
of any marine mammal. As such, the proposed project is not likely to 
adversely impact the availability of any marine mammal species or 
stocks that may otherwise be used for subsistence purposes.

Endangered Species Act (ESA)

    There is one marine mammal species (western DPS Steller sea lion) 
with confirmed occurrence in the project area that is listed as 
endangered under the ESA. The NMFS Permits and Conservation Division 
has initiated consultation with the NMFS Alaska Regional Office 
Protected Resources Division under section 7 of the ESA on the issuance 
of an IHA to UniSea 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.

Proposed Authorization

    As a result of these preliminary determinations, we propose to 
issue an IHA to UniSea, Inc., to conduct the described dock 
construction activities in Iliuliuk Harbor, from March 1, 2016 through 
February 28, 2017, 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 itself. The wording 
contained in this section is proposed for inclusion in the IHA (if 
issued).
    1. This Incidental Harassment Authorization (IHA) is valid from 
March 1, 2016 through February 28, 2017.
    2. This IHA is valid only for pile driving and removal activities 
associated with construction of the UniSea G1 dock in Iliuliuk Harbor, 
Unalaska, AK.
    3. General Conditions
    (a) A copy of this IHA must be in the possession of UniSea, its 
designees, and work crew personnel operating under the authority of 
this IHA.
    (b) The species authorized for taking are the harbor seal (Phoca 
vitulina) and Steller sea lion (Eumetopias jubatus).
    (c) The taking, by Level B harassment only, is limited to the 
species listed in condition 3(b). See Table 6 in the proposed IHA 
authorization for numbers of take authorized.
    (d) The taking by injury (Level A harassment), serious injury, or 
death of any of the species listed in condition 3(b) of the 
Authorization or any taking of any other species of marine mammal is 
prohibited and may result in the modification, suspension, or 
revocation of this IHA.
    (e) UniSea shall conduct briefings between construction supervisors 
and crews, marine mammal monitoring team, and UniSea 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.
    4. Mitigation Measures
    The holder of this Authorization is required to implement the 
following mitigation measures:
    (a) During impact and vibratory pile driving and removal, and down-
the-hole drilling, UniSea shall implement a minimum shutdown zone of 10 
m radius around the pile being driven or removed, to be effective for 
marine mammals. If a marine mammal comes within the relevant zone, such 
operations shall cease.
    (b) UniSea shall establish monitoring locations as described in the 
Marine Mammal Monitoring Plan (Monitoring Plan; attached). For all pile 
driving and removal activities, a minimum of two observers shall be on 
duty, in addition to a monitoring coordinator. The primary 
responsibility of one of these observers shall be to monitor the 
shutdown zone, while the additional observer shall be positioned for 
optimal monitoring of the surrounding waters within Iliuliuk Harbor. 
These observers shall record all observations of marine mammals, 
regardless of distance from the pile being driven, as well as

[[Page 79842]]

behavior and potential behavioral reactions of the animals.
    (c) Monitoring shall take place from fifteen minutes prior to 
initiation of pile driving activity or down-the-hole drilling activity 
through thirty minutes post-completion of such activity. Pre-activity 
monitoring shall be conducted for fifteen minutes to ensure that the 
exclusion zone is clear of marine mammals, and pile driving or down-
the-hole drilling may commence when observers have declared the 
exclusion zone clear of marine mammals. In the event of a delay or 
shutdown of activity resulting from marine mammals in the exclusion 
zone, animals shall be allowed to remain in the exclusion zone (i.e., 
must leave of their own volition) and their behavior shall be monitored 
and documented. Monitoring shall occur throughout the time required to 
drive a pile. The exclusion zone must be determined to be clear during 
periods of good visibility (i.e., the entire exclusion zone and 
surrounding waters must be visible to the naked eye).
    (d) If a marine mammal approaches or enters the exclusion zone, all 
pile driving or down-the-hole drilling activities shall be halted. If 
pile driving is halted or delayed due to the presence of a marine 
mammal, the activity may not commence or resume until either the animal 
has voluntarily left and been visually confirmed beyond the exclusion 
zone, or fifteen minutes have passed without re-detection of the 
animal.
    (e) Monitoring shall be conducted by qualified observers, as 
described in the Monitoring Plan. Trained observers shall be placed 
from the best vantage point(s) practicable (i.e., provides the most 
unobstructed view of the monitoring zones and are at the highest 
elevation possible) to monitor for marine mammals and implement 
shutdown or delay procedures when applicable through communication with 
the equipment operator.
    (f) UniSea shall use sound attenuation devices during impact pile 
driving operations.
    (g) UniSea shall use soft start techniques recommended by NMFS for 
vibratory and impact pile driving. Soft start for vibratory drivers 
requires contractors to initiate sound for fifteen seconds at reduced 
energy followed by a thirty-second waiting period. This procedure is 
repeated two additional times. Soft start for impact drivers requires 
contractors to provide an initial set of strikes at reduced energy, 
followed by a one minute waiting period, then two subsequent reduced 
energy strike sets. Soft start shall be implemented at the start of 
each day's pile driving and at any time following cessation of pile 
driving for a period of thirty minutes or longer. UniSea may 
discontinue use of vibratory soft starts if unsafe working conditions 
believed to result from implementation of the measure are reported by 
the contractor, verified by an independent safety inspection, and 
reported to NMFS.
    (h) In case of fog or reduced visibility, observers must be able to 
see the entire shutdown zone, or pile driving/removal will not be 
initiated until visibility in the zone improves to acceptable levels.
    5. Monitoring
    The holder of this Authorization is required to conduct marine 
mammal monitoring during pile driving activity. Marine mammal 
monitoring and reporting shall be conducted in accordance with the 
Monitoring Plan.
    (a) UniSea shall collect sighting data and behavioral responses to 
pile driving/removal for marine mammal species observed in the region 
of activity during the period of activity. All observers shall be 
trained in marine mammal identification and behaviors, and shall have 
no other construction related tasks while conducting monitoring.
    (b) For all marine mammal monitoring, the information shall be 
recorded as described in the Monitoring Plan.
    6. Reporting
    The holder of this Authorization is required to:
    (a) Submit a draft report on all marine mammal monitoring conducted 
under the IHA within 90 calendar days of the end of the in-water work 
period, or within 45 calendar days of the renewal of the IHA (if 
applicable). A final report shall be prepared and submitted within 
thirty days following resolution of comments on the draft report from 
NMFS. This report must contain the informational elements described in 
the Monitoring Plan, at minimum (see attached).
    (b) Reporting injured or dead marine mammals:
    i. In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by this IHA 
(as determined by the lead observer), such as an injury (Level A 
harassment), serious injury, or mortality, UniSea shall immediately 
cease the specified activities and report the incident to the Office of 
Protected Resources, NMFS, and the Alaska Regional Stranding 
Coordinator, NMFS. The report must include the following information:
    A. Time and date of the incident;
    B. Description of the incident;
    C. Environmental conditions (e.g., wind speed and direction, 
Beaufort sea state, cloud cover, and visibility);
    D. Description of all marine mammal observations in the 24 hours 
preceding the incident;
    E. Species identification or description of the animal(s) involved;
    F. Fate of the animal(s); and
    G. Photographs or video footage of the animal(s).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS will work with UniSea to 
determine what measures are necessary to minimize the likelihood of 
further prohibited take and ensure MMPA compliance. UniSea may not 
resume their activities until notified by NMFS.
    i. In the event that UniSea discovers an injured or dead marine 
mammal, and the lead observer determines that the cause of the injury 
or death is unknown and the death is relatively recent (e.g., in less 
than a moderate state of decomposition), UniSea shall immediately 
report the incident to the Office of Protected Resources, NMFS, and the 
Alaska Regional Stranding Coordinator, NMFS.
    The report must include the same information identified in 6(b)(i) 
of this IHA. Activities may continue while NMFS reviews the 
circumstances of the incident and makes a final determination on the 
cause of the reported injury or death. NMFS will work with UniSea to 
determine whether additional mitigation measures or modifications to 
the activities are appropriate.
    ii. In the event that UniSea discovers an injured or dead marine 
mammal, and the lead observer determines that the injury or death is 
not associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, scavenger damage), UniSea shall report the incident to 
the Office of Protected Resources, NMFS, and the Alaska Regional 
Stranding Coordinator, NMFS, within 24 hours of the discovery. UniSea 
shall provide photographs or video footage or other documentation of 
the stranded animal sighting to NMFS. The cause of injury or death may 
be subject to review and a final determination by NMFS.
    7. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein, or if 
NMFS determines that the authorized taking is having more than a 
negligible impact on the species or stock of affected marine mammals.

[[Page 79843]]

Request for Public Comments

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

    Dated: December 17, 2015.
Perry F. Gayaldo,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2015-32155 Filed 12-22-15; 8:45 am]
BILLING CODE 3510-22-P