[Federal Register Volume 78, Number 178 (Friday, September 13, 2013)]
[Notices]
[Pages 56659-56679]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-22294]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XC824


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a Pier Maintenance Project

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

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

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SUMMARY: NMFS has received a request from the U.S. Navy (Navy) for 
authorization to take marine mammals incidental to construction 
activities as part of a pier maintenance project. Pursuant to the 
Marine Mammal Protection Act (MMPA), NMFS is requesting public comment 
on its proposal to issue an incidental harassment authorization (IHA) 
to the Navy to take, by harassment only, two species of marine mammal 
during the specified activity.

DATES: Comments and information must be received no later than October 
15, 2013.

ADDRESSES: Comments on this proposal should be addressed to Michael 
Payne, 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.Laws@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. Comments received electronically, including all 
attachments, must not exceed a 25-megabyte file size. All comments 
received are a part of the public record. All personal identifying 
information (e.g., name, address) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit confidential 
business information or otherwise sensitive or protected information. 
Attachments to electronic comments will be accepted in Microsoft Word, 
Excel, or Adobe PDF file formats only.

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

SUPPLEMENTARY INFORMATION: 

Availability

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

National Environmental Policy Act

    The Navy has prepared a draft Environmental Assessment (Pier 6 Pile 
Replacement Naval Base Kitsap) in accordance with the National 
Environmental Policy Act (NEPA) and the regulations published by the 
Council on Environmental Quality. It is posted at the aforementioned 
site. NMFS will independently evaluate the EA and determine whether or 
not to adopt it. We may prepare a separate NEPA analysis and 
incorporate relevant portions of the Navy's EA by reference. 
Information in the Navy's application, EA, and this notice collectively 
provide the environmental information related to proposed issuance of 
this IHA for public review and comment. We will review all comments 
submitted in response to this notice as we complete the NEPA process, 
including a decision of whether to sign a Finding of No Significant 
Impact (FONSI), prior to a

[[Page 56660]]

final decision on the incidental take authorization request.

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request by U.S. 
citizens who engage in a specified activity (other than commercial 
fishing) within a specified area, the incidental, but not intentional, 
taking of small numbers of marine mammals, providing that certain 
findings are made and the necessary prescriptions are established.
    The incidental taking of small numbers of marine mammals may be 
allowed only if NMFS (through authority delegated by the Secretary) 
finds that the total taking by the specified activity during the 
specified time period will (i) have a negligible impact on the species 
or stock(s) and (ii) not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant). Further, the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such taking 
must be set forth, either in specific regulations or in an 
authorization.
    The allowance of such incidental taking under section 101(a)(5)(A), 
by harassment, serious injury, death or a combination thereof, requires 
that regulations be established. Subsequently, a Letter of 
Authorization may be issued pursuant to the prescriptions established 
in such regulations, providing that the level of taking will be 
consistent with the findings made for the total taking allowable under 
the specific regulations. Under section 101(a)(5)(D), NMFS may 
authorize such incidental taking by harassment only, for periods of not 
more than 1 year, pursuant to requirements and conditions contained 
within an Incidental Harassment Authorization. The establishment of 
prescriptions through either specific regulations or an authorization 
requires notice and opportunity for public comment.
    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as ``. . . 
an impact resulting from the specified activity that cannot be 
reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.'' Except with respect to certain activities 
not pertinent here, 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; 
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.'' The former is termed Level A harassment and 
the latter is termed Level B harassment.

Summary of Request

    On May 22, 2013, we received a request from the Navy for 
authorization of the taking, by Level B harassment only, of marine 
mammals incidental to pile driving in association with the Pier 6 pile 
replacement project at Naval Base Kitsap Bremerton, WA (NBKB). Through 
the consultation process, that request was modified on June 5, 2013, 
and a final version, which we deemed adequate and complete, was 
submitted on June 12, 2013. In-water work associated with the project 
would be conducted over three years and would occur only during the 
approved in-water work window from June 15 to March 1. This proposed 
IHA would be valid from December 1, 2013, through March 1, 2014. Two 
species of marine mammal are expected to be affected by the specified 
activities: California sea lion (Zalophus californianus californianus) 
and harbor seal (Phoca vitulina richardii). These species may occur 
year-round in the action area, although California sea lions are less 
common and potentially absent in the summer months.
    NBKB serves as the homeport for a nuclear aircraft carrier and 
other Navy vessels and as a shipyard capable of overhauling and 
repairing all types and sizes of ships. Other significant capabilities 
include alteration, construction, deactivation, and dry-docking of 
naval vessels. Pier 6 was completed in 1926 and requires substantial 
maintenance to maintain readiness. Over the length of the entire 
project, the Navy proposes to remove up to 400 deteriorating fender 
piles and to replace them with up to 330 new pre-stressed concrete 
fender piles. Under this proposed IHA, the Navy proposes to conduct 20 
days of vibratory pile removal and 45 days of pile installation with an 
impact hammer.
    Effects to marine mammals from the specified activity are expected 
to result from underwater sound produced by vibratory and impact pile 
driving. In order to assess project impacts, the Navy used thresholds 
recommended by NMFS, outlined later in this document. The Navy assumed 
practical spreading loss and used empirically-measured source levels 
from representative pile driving events to estimate potential marine 
mammal exposures. Predicted exposures are described later in this 
document. The calculations predict that only Level B harassment would 
occur associated with pile driving activities, and required mitigation 
measures further ensure that no more than Level B harassment would 
occur.

Description of the Specified Activity

Specific Geographic Region and Duration

    NBKB is located on the north side of Sinclair Inlet in Puget Sound 
(see Figures 1-1 and 2-1 of the Navy's application). Sinclair Inlet, an 
estuary of Puget Sound extending 3.5 miles southwesterly from its 
connection with the Port Washington Narrows, connects to the main basin 
of Puget Sound through Port Washington Narrows and then Agate Pass to 
the north or Rich Passage to the east. Sinclair Inlet has been 
significantly modified by development activities. Fill associated with 
transportation, commercial, and residential development of NBKB, the 
City of Bremerton, and the local ports of Bremerton and Port Orchard 
has resulted in significant changes to the shoreline. The area 
surrounding Pier 6 is industrialized, armored and adjacent to railroads 
and highways. Sinclair Inlet is also the receiving body for a 
wastewater treatment plant located just west of NBKB. Sinclair Inlet is 
relatively shallow and does not flush fully despite freshwater stream 
inputs.
    The project is expected to require a maximum of 135 days of in-
water impact pile driving work and 65 days of in-water vibratory pile 
removal work over a 3-year period. In-water work would occur only from 
June 15 to March 1 of any year. During the timeframe of this proposed 
IHA (December 1, 2013-March 1, 2014), 45 days of impact pile driving 
and 20 days of vibratory removal would occur.

Description of Specified Activity

    The Navy plans to remove deteriorated fender piles at Pier 6 and 
replace them with prestressed concrete piles. The entire project calls 
for the removal of 380 12-in diameter creosoted timber piles and twenty 
12-in steel pipe piles. These would be replaced with 240 18-in square 
concrete piles and 90 24-in square concrete piles. It is not possible 
to specify accurately the number of piles that might be installed or 
removed in any given work window, due to various delays that may be 
expected during construction work and uncertainty inherent to 
estimating production rates. The Navy assumes a notional production 
rate of four piles per day in determining the number of

[[Page 56661]]

days of pile driving expected, and scheduling--as well as exposure 
analyses--is based on this assumption.
    All piles are planned for removal via vibratory driver. The driver 
is suspended from a barge-mounted crane and positioned on top of a 
pile. Vibration from the activated driver loosens the pile from the 
substrate. Once the pile is released, the crane raises the driver and 
pulls the pile from the sediment. Vibratory extraction is expected to 
take approximately 5-30 minutes per pile. If piles break during 
removal, the remaining portion may be removed via direct pull or with a 
clamshell bucket. Replacement piles would be installed via impact 
driver and would require approximately 15-60 minutes of driving time 
per pile, depending on subsurface conditions. Impact driving and/or 
vibratory removal could occur on any work day during the period of the 
proposed IHA.

Description of Sound Sources and Distances to Thresholds

    Impacts from the specified activity on marine mammals are expected 
to result from the production of underwater sound; therefore, we 
provide a brief technical background on sound, the characteristics of 
certain sound types, and on metrics used in this proposal.

Background

    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 
(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), and 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) and in 
the context of airborne sound pressure to 20 [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.
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. Rms is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick, 1983). Rms accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper, 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures. Unless otherwise noted, 
all references to SPLs in this document are in dB rms and are 
referenced as described above.
    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.

Ambient Sound

    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 sound 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 sound 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 sound at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times.
     Biological: Marine mammals can contribute significantly to 
ambient sound 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 sound 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 sound 
typically dominates the total ambient sound for frequencies between 20 
and 300 Hz. In general, the frequencies of anthropogenic sounds are 
below 1 kHz and, if higher frequency sound levels are created, they 
attenuate rapidly. 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. Known sound 
levels and frequency ranges associated with anthropogenic sources 
similar to those that would be used for this project are summarized in 
Table 1.

                          Table 1--Representative Sound Levels of Anthropogenic Sources
----------------------------------------------------------------------------------------------------------------
                                         Frequency     Underwater sound level (dB
            Sound source                range (Hz)           re 1 [micro]Pa)                  Reference
----------------------------------------------------------------------------------------------------------------
Small vessels.......................       250-1,000  151 dB rms at 1 m...........  Richardson et al., 1995.
Tug docking gravel barge............       200-1,000  149 dB rms at 100 m.........  Blackwell and Greene, 2002.

[[Page 56662]]

 
Vibratory driving of 72-in (1.8 m)          10-1,500  180 dB rms at 10 m..........  Reyff, 2007.
 steel pipe pile.
Impact driving of 36-in steel pipe          10-1,500  195 dB rms at 10 m..........  Laughlin, 2007.
 pile.
Impact driving of 66-in cast-in-            10-1,500  195 dB rms at 10 m..........  Reviewed in Hastings and
 steel-shell pile.                                                                   Popper, 2005.
----------------------------------------------------------------------------------------------------------------

    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    The underwater acoustic environment in Sinclair Inlet is likely to 
be dominated by noise from day-to-day port and vessel activities. 
Normal port activities include vessel traffic from aircraft carriers, 
large ships, submarines, support vessels, and security boats, and 
loading and maintenance operations. Other sources of human-generated 
underwater sound in the area are recreational vessels, industrial ship 
noise, and ferry traffic at the adjacent Washington State Ferry 
Terminal. In 2009, the average broadband (100 Hz-20 kHz) underwater 
noise level at NBK Bangor in the Hood Canal was measured at 114 dB 
(Slater, 2009), which is within the range of levels reported for a 
number of sites within the greater Puget Sound region (95-135 dB; e.g., 
Carlson et al., 2005; Veirs and Veirs, 2006). Measurements near ferry 
terminals in Puget Sound, such as the Bremerton terminal adjacent to 
NBKB, resulted in median noise levels (50% cumulative distribution 
function) between 106 and 133 dB (Laughlin, 2012). Although no specific 
measurements have been made at NBKB, it is reasonable to believe that 
levels may generally be higher than at NBK Bangor as there is a greater 
degree of activity, that levels periodically exceed the 120-dB 
threshold and, therefore, that the high levels of anthropogenic 
activity in the area create an environment far different from quieter 
habitats where behavioral reactions to sounds around the 120-dB 
threshold have been observed (e.g., Malme et al., 1984, 1988).

Sound Source Characteristics

    In-water construction activities associated with the project would 
include impact pile driving and vibratory pile removal. The sounds 
produced by these activities fall into one of two sound types: Pulsed 
and non-pulsed (defined in the following). The distinction between 
these two general sound types is important because they have differing 
potential to cause physical effects, particularly with regard to 
hearing (e.g., Ward, 1997 in Southall et al., 2007). Please see 
Southall et al., (2007) for an in-depth discussion of these concepts.
    Pulsed sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) produce signals that are brief (typically 
considered to be less than 1 sec), broadband, atonal transients (ANSI, 
1986; Harris, 1998; NIOSH, 1998; ISO, 2003; ANSI, 2005) and occur 
either as isolated events or repeated in some succession. Pulsed sounds 
are all characterized by a relatively rapid rise from ambient pressure 
to a maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or non-continuous (ANSI, 1995; 
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling or 
dredging, vibratory pile driving, and active sonar systems. The 
duration of such sounds, as received at a distance, can be greatly 
extended in a highly reverberant environment.
    Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper, 2005). 
Vibratory hammers cause liquefaction of surrounding sediment through 
vibration, allowing installation as the weight of the hammer push piles 
down or removal as the crane pulls up. 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).

Sound Thresholds

    NMFS currently uses acoustic exposure thresholds as important tools 
to help better characterize and quantify the effects of human-induced 
noise on marine mammals. These thresholds have predominantly been 
presented in the form of single received levels for particular source 
categories (e.g., impulse, continuous, or explosive) above which an 
exposed animal would be predicted to incur auditory injury or be 
behaviorally harassed. Current NMFS practice (in relation to the MMPA) 
regarding exposure of marine mammals to sound is that cetaceans and 
pinnipeds exposed to sound levels of 180 and 190 dB rms or above, 
respectively, are considered to have been taken by Level A (i.e., 
injurious) harassment, while behavioral harassment (Level B) is 
considered to have occurred when marine mammals are exposed to sounds 
at or above 120 dB rms for continuous sound (such as

[[Page 56663]]

will be produced by vibratory pile driving) and 160 dB rms for pulsed 
sound (produced by impact pile driving), but below injurious 
thresholds. For airborne sound, pinniped disturbance from haul-outs has 
been documented at 100 dB (unweighted) for pinnipeds in general, and at 
90 dB (unweighted) for harbor seals. NMFS uses these levels as 
guidelines to estimate when harassment may occur.
    NMFS is in the process of revising these acoustic thresholds, with 
the first step being to identify new auditory injury criteria for all 
source types and new behavioral criteria for seismic activities 
(primarily airgun-type sources). For more information on that process, 
please visit http://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

Distance to Sound Thresholds

    Underwater Sound--Pile driving generates underwater noise that can 
potentially result in disturbance to marine mammals in the project 
area. In order to estimate the distance at which sound produced by the 
specified activity would attenuate to relevant thresholds, one must, at 
minimum, be able to reasonably approximate source levels and 
transmission loss (TL), which is the decrease in acoustic intensity as 
an acoustic pressure wave propagates out from a source. In general, the 
sound pressure level (SPL) at some distance away from the source (e.g., 
driven pile) is governed by a measured source level, minus the TL of 
the energy as it dissipates with distance.
    The degree to which underwater sound propagates away from a sound 
source is dependent on a variety of factors, including source depth and 
frequency, receiver depth, water depth, bottom composition and 
topography, presence or absence of reflective or absorptive in-water 
structures, and oceanographic conditions such as temperature, current, 
and water chemistry. The general formula for underwater TL neglects 
loss due to scattering and absorption, which is assumed to be zero 
here. Spherical spreading occurs in a perfectly unobstructed (free-
field) environment not limited by depth or water surface, resulting in 
a 6 dB reduction in sound level for each doubling of distance from the 
source (20*log[range]). Cylindrical spreading occurs in an environment 
in which sound propagation is bounded by the water surface and sea 
bottom, resulting in a reduction of 3 dB in sound level for each 
doubling of distance from the source (10*log[range]). A practical 
spreading value of 15 (4.5 dB reduction in sound level for each 
doubling of distance) is often used under intermediate conditions, and 
is assumed here.
    Source level, or the intensity of pile driving sound, is greatly 
influenced by factors such as the type of piles, hammers, and the 
physical environment in which the activity takes place. A number of 
studies have measured sound produced during underwater pile driving 
projects, primarily during work conducted by the Washington State 
Department of Transportation and the California Department of 
Transportation. In order to determine reasonable SPLs and their 
associated effects on marine mammals that are likely to result from 
pile driving at NBKB, the Navy evaluated existing data on the basis of 
pile materials and driver type. Table 2 shows the most appropriate 
proxy values to use for determining distances to relevant thresholds.

                               Table 2--Summary of proxy measured underwater SPLs
----------------------------------------------------------------------------------------------------------------
              Location                       Method          Pile size and material         Measured SPLs
----------------------------------------------------------------------------------------------------------------
Berth 22, Port of Oakland \1\......  Impact................  24-in concrete........  176 dB at 10 m.
Mad River Slough, CA \1\...........  Vibratory.............  13-in steel pipe......  155 dB at 10 m.
Port Townsend, WA \2\..............  Vibratory (removal)...  12-in timber..........  150 dB at 16 m.
----------------------------------------------------------------------------------------------------------------
Sources:
\1\ CalTrans, 2012;
\2\ Laughlin, 2011

    The value from Berth 22 was selected as representative of the 
largest concrete pile size to be installed and may be conservative when 
smaller concrete piles are driven. The value from Mad River Slough is 
for vibratory installation and would likely be conservative when 
applied to vibratory extraction, which would be expected to produce 
lower SPLs than vibratory installation of same-sized piles. All 
calculated distances to and the total area encompassed by the marine 
mammal sound thresholds are provided in Table 3.

                   Table 3--Distances to Relevant Sound Thresholds and Areas of Ensonification
----------------------------------------------------------------------------------------------------------------
                                                         Distance to threshold (m) and associated area of
                                                                      ensonification (km\2\)
                   Description                   ---------------------------------------------------------------
                                                      190 dB          180 dB          160 dB          120 dB
----------------------------------------------------------------------------------------------------------------
Concrete piles, impact..........................    1.2, <0.0001     5.4, 0.0001       117, 0.04             n/a
Steel piles, vibratory..........................               0               0             n/a   \2\2,154, 7.5
Timber piles, vibratory.........................               0               0             n/a     1,585; 5.04
----------------------------------------------------------------------------------------------------------------
\1\ SPLs used for calculations were: 191 dB for impact driving, 170 dB for vibratory removal of steel piles, and
  168 dB for vibratory removal of timber piles.
\2\ Areas presented take into account attenuation and/or shadowing by land. Please see Figures B-1 and B-2 in
  the Navy's application.

    Sinclair Inlet does not represent open water, or free field, 
conditions. Therefore, sounds would attenuate according to the 
shoreline topography. Distances shown in Table 1 are estimated for 
free-field conditions, but areas are calculated per the actual 
conditions of the action area. See Figures B-1 and B-2 of the Navy's 
application for a depiction of areas in which each underwater sound 
threshold is predicted to occur at the project area due to pile 
driving.
    Airborne Sound--Pile driving can generate airborne sound that could

[[Page 56664]]

potentially result in disturbance to marine mammals (specifically, 
pinnipeds) which are hauled out or at the water's surface. As a result, 
the Navy analyzed the potential for pinnipeds hauled out or swimming at 
the surface near NBKB to be exposed to airborne SPLs that could result 
in Level B behavioral harassment. Although there is no official 
airborne sound threshold, NMFS assumes for purposes of the MMPA that 
behavioral disturbance can occur upon exposure to sounds above 100 dB 
re 20 [micro]Pa rms (unweighted) for all pinnipeds, except harbor 
seals. For harbor seals, the threshold is 90 dB re 20 [micro]Pa rms 
(unweighted).
    As was discussed for 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 takes place. As before, measured values from other studies 
were used as proxy values to determine reasonable airborne SPLs and 
their associated effects on marine mammals that are likely to result 
from pile driving at NBKB. There are no measurements known for 
unweighted airborne sound from either impact driving of concrete piles 
or for vibratory driving of timber piles.

                                Table 4--Summary of Proxy Measured Airborne SPLs
----------------------------------------------------------------------------------------------------------------
              Location                       Method          Pile size and material         Measured SPLs
----------------------------------------------------------------------------------------------------------------
Test Pile Program, Hood Canal \1\..  Impact................  24-in steel pipe......  89 dB at 15 m.
Wahkiakum Ferry Terminal, WA \2\...  Vibratory.............  18-in steel pipe......  87.5 dB at 15 m.
----------------------------------------------------------------------------------------------------------------
Sources:
\1\ Illingworth & Rodkin, Inc., 2012;
\2\ Laughlin, 2010

    Steel piles generally produce louder source levels than do 
similarly sized concrete or timber piles. Similarly, the value shown 
here for the larger steel piles (18-in) would likely be louder than 
smaller steel piles or timber piles. Therefore, these values will 
likely overestimate the distances to relevant thresholds. Based on 
these values and the assumption of spherical spreading loss, distances 
to relevant thresholds and associated areas of ensonification are 
presented in Table 5; these areas are depicted in Figure B-3 of the 
Navy's application.

                   Table 5--Distances to Relevant Sound Thresholds and Areas of Ensonification
----------------------------------------------------------------------------------------------------------------
                                                                                 Distance to threshold (m) and
                                                                               associated area of ensonification
                                              Threshold, re 20 [mu]Pa rms                   (m\2\)
                  Group                               (unweighted)           -----------------------------------
                                                                                                    Vibratory
                                                                               Impact driving        driving
----------------------------------------------------------------------------------------------------------------
Harbor seals.............................  90 dB............................           13, 169           11, 121
California sea lions.....................  100 dB...........................             5, 25             4, 16
----------------------------------------------------------------------------------------------------------------
\1\ SPLs used for calculations were: 112.5 dB for impact driving, 111 dB for use of a vibratory hammer.

    There are no haul-out opportunities within these small zones, which 
are encompassed by the zones estimated for underwater sound. Protective 
measures would be in place out to the distances calculated for the 
underwater thresholds, and the distances for the airborne thresholds 
would be covered fully by mitigation and monitoring measures in place 
for underwater sound thresholds. We recognize that pinnipeds in water 
that are within the area of ensonification for airborne sound could be 
incidentally taken by either underwater or airborne sound or both. We 
consider these incidences of harassment to be accounted for in the take 
estimates for underwater sound. The effects of airborne sound are not 
considered further in this document's analysis.

Description of Marine Mammals in the Area of the Specified Activity

    There are five marine mammal species with records of occurrence in 
waters of Sinclair Inlet in the action area. These are the California 
sea lion, harbor seal, Steller sea lion (eastern stock only; Eumetopias 
jubatus monteriensis), gray whale (Eschrichtius robustus), and killer 
whale (Orcinus orca). For the killer whale, both transient (west coast 
stock) and resident (southern stock) animals, which are currently 
considered unnamed subspecies (Committee on Taxonomy, 2012), have 
occurred in the area. However, southern resident animals are known to 
have occurred only once, with the last confirmed sighting from 1997 in 
Dyes Inlet. A group of 19 whales from the L-25 subpod entered and 
stayed in Dyes Inlet, which connects to Sinclair Inlet northeast of 
NBKB, for 30 days. Dyes Inlet may be reached only by traversing from 
Sinclair Inlet through the Port Washington Narrows, a narrow connecting 
body that is crossed by two bridges, and it was speculated at the time 
that the whales' long stay was the result of a reluctance to traverse 
back through the Narrows and under the two bridges. There is one other 
unconfirmed report of a single southern resident animal occurring in 
the project area, in January 2009. Of these stocks, the Steller sea 
lion and southern resident killer whales are listed under the 
Endangered Species Act (ESA), with the eastern stock of Steller sea 
lions listed as threatened and the southern resident stock of killer 
whales listed as endangered.
    An additional seven species have confirmed occurrence in Puget 
Sound, but are considered rare to extralimital in Sinclair Inlet and 
the surrounding waters. These species--the humpback whale (Megaptera 
novaeangliae), minke whale (Balaenoptera acutorostrata scammoni), 
Pacific white-sided dolphin (Lagenorhynchus obliquidens), harbor 
porpoise (Phocoena phocoena vomerina), Dall's porpoise (Phocoenoides 
dalli dalli), and northern elephant seal (Mirounga angustirostris)--
along with the southern resident killer whale, are considered extremely 
unlikely to occur in the action area or to be affected by the specified 
activities, and are not considered further in this document. A review 
of sightings records available from the Orca Network 
(www.orcanetwork.org; accessed August 15, 2013) confirms that there are 
no

[[Page 56665]]

recorded observations of these species in the action area (with the 
exception of the appearance of southern residents in 1997).
    This section summarizes the population status and abundance of 
these species. We have reviewed the Navy's detailed species 
descriptions, including life history information, for accuracy and 
completeness and refer the reader to Sections 3 and 4 of the Navy's 
application instead of reprinting the information here. Table 5 lists 
the marine mammal species with expected potential for occurrence in the 
vicinity of NBKB during the project timeframe. The following 
information is summarized largely from NMFS Stock Assessment Reports.

                       Table 6--Marine Mammals Potentially Present in the Vicinity of NBKB
----------------------------------------------------------------------------------------------------------------
                                       Stock abundance\1\ (CV,   Relative occurrence in
               Species                          Nmin)                Sinclair Inlet        Season of occurrence
----------------------------------------------------------------------------------------------------------------
California sea lion, U.S. Stock......   296,750 (n/a, 153,337)  Common.................  Year-round, excluding
                                                                                          July.
Harbor seal, WA inland waters stock..         \2\14,612 (0.15,  Common.................  Year-round.
                                                       12,844)
Steller sea lion, Eastern stock......      58,334-72,223 (n/a,  Occasional presence....  Seasonal (Oct-May).
                                                       52,847)
Killer whale, West Coast transient                   354 (n/a)  Uncommon...............  Year-round.
 stock.
Gray whale, Eastern North Pacific       19,126 (0.071, 18,017)  Uncommon...............  Year-round.
 stock.
----------------------------------------------------------------------------------------------------------------
\1\ NMFS marine mammal stock assessment reports at: http://www.nmfs.noaa.gov/pr/sars/species.htm. CV is
  coefficient of variation; Nmin is the minimum estimate of stock abundance.
\2\ This abundance estimate is greater than eight years old and is therefore not considered current.

Harbor Seal

    Harbor seals inhabit coastal and estuarine waters and shoreline 
areas of the northern hemisphere from temperate to polar regions. The 
eastern North Pacific subspecies is found from Baja California north to 
the Aleutian Islands and into the Bering Sea. Multiple lines of 
evidence support the existence of geographic structure among harbor 
seal populations from California to Alaska (Carretta et al., 2011). 
However, because stock boundaries are difficult to meaningfully draw 
from a biological perspective, three separate harbor seal stocks are 
recognized for management purposes along the west coast of the 
continental U.S.: (1) Inland waters of Washington (including Hood 
Canal, Puget Sound, and the Strait of Juan de Fuca out to Cape 
Flattery), (2) outer coast of Oregon and Washington, and (3) California 
(Carretta et al., 2011). Multiple stocks are recognized in Alaska. 
Samples from Washington, Oregon, and California demonstrate a high 
level of genetic diversity and indicate that the harbor seals of 
Washington inland waters possess unique haplotypes not found in seals 
from the coasts of Washington, Oregon, and California (Lamont et al., 
1996). Only the Washington inland waters stock may be found in the 
project area.
    Washington inland waters harbor seals are not protected under the 
ESA or listed as depleted under the MMPA. Because there is no current 
abundance estimate for this stock, there is no current estimate of 
potential biological removal (PBR). However, because annual human-
caused mortality (13) is significantly less than the previously 
calculated PBR (771) the stock is not considered strategic under the 
MMPA. The stock is considered to be within its optimum sustainable 
population (OSP) level.
    The best abundance estimate of the Washington inland waters stock 
of harbor seals is 14,612 (CV = 0.15) and the minimum population size 
of this stock is 12,884 individuals (Carretta et al., 2011). Aerial 
surveys of harbor seals in Washington were conducted during the pupping 
season in 1999, during which time the total numbers of hauled-out seals 
(including pups) were counted (Jeffries et al., 2003). Radio-tagging 
studies conducted at six locations collected information on harbor seal 
haul-out patterns in 1991-92, resulting in a correction factor of 1.53 
(CV = 0.065) to account for animals in the water which are missed 
during the aerial surveys (Huber et al., 2001), which, coupled with the 
aerial survey counts, provides the abundance estimate. Because the 
estimate is greater than eight years old, NMFS does not consider it 
current. However, it does represent the best available information 
regarding stock abundance. Harbor seal counts in Washington State 
increased at an annual rate of ten percent from 1991-96 (Jeffries et 
al., 1997). However, a logistic model fit to abundance data from 1978-
99 resulted in an estimated maximum net productivity rate of 12.6 
percent (95% CI = 9.4-18.7%) and the population is thought to be stable 
(Jeffries et al., 2003).
    Historical levels of harbor seal abundance in Washington are 
unknown. The population was apparently greatly reduced during the 1940s 
and 1950s due to a state-financed bounty program and remained low 
during the 1970s before rebounding to current levels (Carretta et al., 
2011). Data from 2004-08 indicate that a minimum of 3.8 harbor seals 
are killed annually in Washington inland waters commercial fisheries 
(Carretta et al., 2011). Animals captured east of Cape Flattery are 
assumed to belong to this stock. The estimate is considered a minimum 
because there are likely additional animals killed in unobserved 
fisheries and because not all animals stranding as a result of 
fisheries interactions are likely to be recorded. Another 9.2 harbor 
seals per year are estimated to be killed as a result of various non-
fisheries human interactions (Carretta et al., 2011). Tribal 
subsistence takes of this stock may occur, but no data on recent takes 
are available.
    Harbor seal numbers increase from January through April and then 
decrease from May through August as the harbor seals move to adjacent 
bays on the outer coast of Washington for the pupping season. From 
April through mid-July, female harbor seals haul out on the outer coast 
of Washington at pupping sites to give birth. Harbor seals are expected 
to occur in Sinclair Inlet and NBKB at all times of the year. No 
permanent haul-out has been identified at NBKB. The nearest known haul-
outs are along the south side of Sinclair Inlet on log breakwaters at 
several marinas in Port Orchard, approximately 1 mile from Pier 6. An 
additional haul-out location in Dyes Inlet, approximately 8.5 km north 
and west (shoreline distance), was believed to support less than 100 
seals (Jeffries et al., 2000). Please see Figure 4-2 of the Navy's 
application.

California Sea Lion

    California sea lions range from the Gulf of California north to the 
Gulf of Alaska, with breeding areas located in the Gulf of California, 
western Baja

[[Page 56666]]

California, and southern California. Five genetically distinct 
geographic populations have been identified: (1) Pacific Temperate, (2) 
Pacific Subtropical, (3) Southern Gulf of California, (4) Central Gulf 
of California and (5) Northern Gulf of California (Schramm et al., 
2009). Rookeries for the Pacific Temperate population are found within 
U.S. waters and just south of the U.S.-Mexico border, and animals 
belonging to this population may be found from the Gulf of Alaska to 
Mexican waters off Baja California. For management purposes, a stock of 
California sea lions comprising those animals at rookeries within the 
U.S. is defined (i.e., the U.S. stock of California sea lions) 
(Carretta et al., 2011). Pup production at the Coronado Islands rookery 
in Mexican waters is considered an insignificant contribution to the 
overall size of the Pacific Temperate population (Lowry and Maravilla-
Chavez, 2005).
    California sea lions are not protected under the ESA or listed as 
depleted under the MMPA. Total annual human-caused mortality (at least 
431) is substantially less than the potential biological removal (PBR, 
estimated at 9,200 per year); therefore, California sea lions are not 
considered a strategic stock under the MMPA. There are indications that 
the California sea lion may have reached or is approaching carrying 
capacity, although more data are needed to confirm that leveling in 
growth persists (Carretta et al., 2011).
    The best abundance estimate of the U.S. stock of California sea 
lions is 296,750 and the minimum population size of this stock is 
153,337 individuals (Carretta et al., 2011). The entire population 
cannot be counted because all age and sex classes are never ashore at 
the same time; therefore, the best abundance estimate is determined 
from the number of births and the proportion of pups in the population, 
with censuses conducted in July after all pups have been born. 
Specifically, the pup count for rookeries in southern California from 
2008 was adjusted for pre-census mortality and then multiplied by the 
inverse of the fraction of newborn pups in the population (Carretta et 
al., 2011). The minimum population size was determined from counts of 
all age and sex classes that were ashore at all the major rookeries and 
haul-out sites in southern and central California during the 2007 
breeding season, including all California sea lions counted during the 
July 2007 census at the Channel Islands in southern California and at 
haul-out sites located between Point Conception and Point Reyes, 
California (Carretta et al., 2011). An additional unknown number of 
California sea lions are at sea or hauled out at locations that were 
not censused and are not accounted for in the minimum population size.
    Trends in pup counts from 1975 through 2008 have been assessed for 
four rookeries in southern California and for haul-outs in central and 
northern California. During this time period counts of pups increased 
at an annual rate of 5.4 percent, excluding six El Nino years when pup 
production declined dramatically before quickly rebounding (Carretta et 
al., 2011). The maximum population growth rate was 9.2 percent when pup 
counts from the El Ni[ntilde]o years were removed. However, the 
apparent growth rate from the population trajectory underestimates the 
intrinsic growth rate because it does not consider human-caused 
mortality occurring during the time series; the default maximum net 
productivity rate for pinnipeds (12 percent per year) is considered 
appropriate for California sea lions (Carretta et al., 2011).
    Historic exploitation of California sea lions include harvest for 
food by Native Americans in pre-historic times and for oil and hides in 
the mid-1800s, as well as exploitation for a variety of reasons more 
recently (Carretta et al., 2011). There are few historical records to 
document the effects of such exploitation on sea lion abundance (Lowry 
et al., 1992). Data from 2003-09 indicate that a minimum of 337 (CV = 
0.56) California sea lions are killed annually in commercial fisheries. 
In addition, a summary of stranding database records for 2005-09 shows 
an annual average of 65 such events, which is likely a gross 
underestimate because most carcasses are not recovered. California sea 
lions may also be removed because of predation on endangered salmonids 
(17 per year, 2008-10) or incidentally captured during scientific 
research (3 per year, 2005-09) (Carretta et al., 2011). Sea lion 
mortality has also been linked to the algal-produced neurotoxin domoic 
acid (Scholin et al., 2000). There is currently an Unusual Mortality 
Event (UME) declaration in effect for California sea lions. Future 
mortality may be expected to occur, due to the sporadic occurrence of 
such harmful algal blooms. Beginning in January 2013, elevated 
strandings of California sea lion pups have been observed in Southern 
California, with live sea lion strandings nearly three times higher 
than the historical average. The causes of this UME are under 
investigation (http://www.nmfs.noaa.gov/pr/health/mmume/californiasealions2013.htm; accessed August 20, 2013).
    California sea lions were not recorded in Puget Sound until 
approximately 1979 (Steiger and Calambokidis, 1986). Everitt et al. 
(1980) reported the initial occurrence of large numbers in northern 
Puget Sound in the spring of that year. Similar sightings and increases 
in numbers were documented throughout the region after the initial 
sighting (Steiger and Calambokidis 1986), including urbanized areas 
such as Elliot Bay near Seattle and heavily used areas of central Puget 
Sound (Gearin et al., 1986). California sea lions now use haul-out 
sites within all regions of Washington inland waters (Jeffries et al., 
2000). California sea lions migrate northward along the coast to 
central and northern California, Oregon, Washington, and Vancouver 
Island during the non-breeding season from September to May and return 
south the following spring (Mate, 1975; Bonnell et al., 1983). Jeffries 
et al. (2000) estimated that 3,000 to 5,000 individuals make this trip, 
with peak numbers of up to 1,000 occurring in Puget Sound during this 
time period. The California sea lion population has grown 
substantially, and it is likely that the numbers migrating to 
Washington inland waters have increased as well.
    Occurrence in Puget Sound is typically between September and June 
with peak abundance between September and May. During summer months 
(June through August) and associated breeding periods, California sea 
lions are largely returning to rookeries in California and are not 
present in large numbers in Washington inland waters. They are known to 
utilize a diversity of man-made structures for hauling out (Riedman, 
1990) and, although there are no regular California sea lion haul-outs 
known within Sinclair Inlet (Jeffries et al., 2000), they are 
frequently observed hauled out at several opportune areas at NBKB 
(e.g., floating security fence; see Figures 4-1 and 4-2 of the Navy's 
application). The next nearest recorded haul-outs are navigation buoys 
and net pens in Rich Passage, approximately 10 km east of NBKB 
(Jeffries et al., 2000).

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. Based on distribution, population response, phenotypic, and 
genotypic data, two separate stocks of Steller sea lions are recognized 
within U. S. waters, with the population

[[Page 56667]]

divided into western and eastern distinct population segments (DPSs) at 
144[deg] W (Cape Suckling, Alaska) (Loughlin, 1997). The eastern DPS 
extends from California to Alaska, including the Gulf of Alaska, and is 
the only stock that may occur in the Hood Canal.
    Steller sea lions were listed as threatened range-wide under the 
ESA in 1990. After division into two stocks, the western stock was 
listed as endangered in 1997, while the eastern stock remained 
classified as threatened. NMFS proposed on April 18, 2012, that the 
eastern stock is recovered and should be delisted. Pending a final 
decision on that proposal, the stock remains designated as depleted 
under the MMPA by default due to its threatened status under the ESA. 
However, the minimum estimated annual level of human-caused mortality 
(59.1) is significantly less than the calculated potential biological 
removal (PBR) of 2,378 animals. The stock has shown a consistent, long-
term rate of increase, which may indicate that it is reaching optimum 
sustainable population (OSP) size (Allen and Angliss, 2013).
    The most recent population estimate for the eastern stock is 
estimated to be within the range 58,334 to 72,223 (Allen and Angliss, 
2013). Calkins and Pitcher (1982) and Pitcher et al., (2007) concluded 
that the total Steller sea lion population could be estimated by 
multiplying pup counts by a factor based on the birth rate, sex and age 
structure, and growth rate of the population. This range is determined 
by multiplying the most recent pup counts available by region, from 
2006 (British Columbia) and 2009 (U.S.), by pup multipliers of either 
4.2 or 5.2 (Pitcher et al., 2007). The pup multipliers varied depending 
on the vital rate parameter that resulted in the growth rate: as low as 
4.2 if it were due to high fecundity, and as high as 5.2 if it were due 
to low juvenile mortality. These are not minimum population estimates, 
since they are extrapolated from pup counts from photographs taken in 
2006-2009, and demographic parameters are estimated for an increasing 
population. The minimum population, which is estimated at 52,847 
individuals, was calculated by adding the most recent non-pup and pup 
counts from all sites surveyed; this estimate is not corrected for 
animals at sea. The most recent minimum count for Steller sea lions in 
Washington was 516 in 2001 (Pitcher et al., 2007).
    The abundance of the Eastern DPS of Steller sea lions is increasing 
throughout the northern portion of its range (Southeast Alaska and 
British Columbia; Merrick et al., 1992; Sease et al., 2001; Olesiuk and 
Trites, 2003; Olesiuk, 2008; NMFS, 2008), and stable or increasing 
slowly in the central portion (Oregon through central California; NMFS, 
2008). In the southern end of its range (Channel Islands in southern 
California; Le Boeuf et al., 1991), it has declined significantly since 
the late 1930s, and several rookeries and haul-outs have been 
abandoned. Changes in ocean conditions (e.g., warmer temperatures) may 
be contributing to habitat changes that favor California sea lions over 
Steller sea lions in the southern portion of the Steller's range (NMFS, 
2008). Between the 1970s and 2002, the average annual population growth 
rate of eastern Steller sea lions was 3.1 percent (Pitcher et al., 
2007). Pitcher et al. (2007) concluded this rate did not represent a 
maximum rate of increase, though, and the maximum theoretical net 
productivity rate for pinnipeds (12 percent) is considered appropriate 
(Allen and Angliss, 2013).
    Data from 2005-10 show a total mean annual mortality rate of 5.71 
(CV = 0.23) sea lions per year from observed fisheries and 11.25 
reported takes per year that could not be assigned to specific 
fisheries, for a total from all fisheries of 17 eastern Steller sea 
lions (Allen and Angliss, 2013). In addition, opportunistic 
observations and stranding data indicate that an additional 28.8 
animals are killed or seriously injured each year through interaction 
with commercial and recreational troll fisheries and by entanglement. 
For the most recent years from which data are available (2004-08), 11.9 
animals were taken per year by subsistence harvest in Alaska. Sea lion 
deaths are also known to occur because of illegal shooting, vessel 
strikes, or capture in research gear and other traps, totaling 1.4 
animals per year from 2006-10. The total annual human-caused mortality 
is a minimum estimate because takes via fisheries interactions and 
subsistence harvest in Canada are poorly known, although are believed 
to be small.
    The eastern stock breeds in rookeries located in southeast Alaska, 
British Columbia, Oregon, and California. There are no known breeding 
rookeries in Washington (Allen and Angliss, 2013) but eastern stock 
Steller sea lions are present year-round along the outer coast of 
Washington, including immature animals or non-breeding adults of both 
sexes. In Washington, Steller sea lions primarily occur at haul-out 
sites along the outer coast from the Columbia River to Cape Flattery 
and in inland waters sites along the Vancouver Island coastline of the 
Strait of Juan de Fuca (Jeffries et al., 2000; Olesiuk and Trites, 
2003; Olesiuk, 2008). Numbers vary seasonally in Washington waters with 
peak numbers present during the fall and winter months (Jeffries et 
al., 2000). More recently, five winter haul-out sites used by adult and 
subadult Steller sea lions have been identified in Puget Sound (see 
Figure 4-2 of the Navy's application). Numbers of animals observed at 
all of these sites combined were less than 200 individuals. The closest 
haul-out, with approximately 30 to 50 individuals near the Navy's 
Manchester Fuel Depot, occurs approximately 6.5 mi from the project 
site but is physically separated by various land masses and waterways. 
However, one Steller sea lion was observed hauled out on the floating 
security barrier at NBKB in November 2012. No permanent haul-out has 
been identified in the project area and Steller sea lion presence is 
considered to be rare and seasonal.

Killer Whale

    Killer whales are one of the most cosmopolitan marine mammals, 
found in all oceans with no apparent restrictions on temperature or 
depth, although they do occur at higher densities in colder, more 
productive waters at high latitudes and are more common in nearshore 
waters (Leatherwood and Dahlheim, 1978; Forney and Wade, 2006; Allen 
and Angliss, 2011). Killer whales are found throughout the North 
Pacific, including the entire Alaska coast, in British Columbia and 
Washington inland waterways, and along the outer coasts of Washington, 
Oregon, and California. On the basis of differences in morphology, 
ecology, genetics, and behavior, populations of killer whales have 
largely been classified as ``resident'', ``transient'', or ``offshore'' 
(e.g., Dahlheim et al., 2008). Several studies have also provided 
evidence that these ecotypes are genetically distinct, and that further 
genetic differentiation is present between subpopulations of the 
resident and transient ecotypes (e.g., Barrett-Lennard, 2000). The 
taxonomy of killer whales is unresolved, with expert opinion generally 
following one of two lines: killer whales are either (1) a single 
highly variable species, with locally differentiated ecotypes 
representing recently evolved and relatively ephemeral forms not 
deserving species status, or (2) multiple species, supported by the 
congruence of several lines of evidence for the distinctness of 
sympatrically occurring forms (Krahn et al., 2004). Resident and

[[Page 56668]]

transient whales are currently considered to be unnamed subspecies 
(Committee on Taxonomy, 2011).
    The resident and transient populations have been divided further 
into different subpopulations on the basis of genetic analyses, 
distribution, and other factors. Recognized stocks in the North Pacific 
include Alaska Residents, Northern Residents, Southern Residents, Gulf 
of Alaska, Aleutian Islands, and Bering Sea Transients, and West Coast 
Transients, along with a single offshore stock. West coast transient 
killer whales, which occur from California through southeastern Alaska, 
are the only type expected to potentially occur in the project area.
    West Coast transient killer whales are not protected under the ESA 
or listed as depleted under the MMPA. The estimated annual level of 
human-caused mortality (0) does not exceed the calculated PBR (3.5); 
therefore, West Coast Transient killer whales are not considered a 
strategic stock under the MMPA. It is thought that the stock grew 
rapidly from the mid-1970s to mid-1990s as a result of a combination of 
high birth rate, survival, as well as greater immigration of animals 
into the nearshore study area (DFO, 2009). The rapid growth of the 
population during this period coincided with a dramatic increase in the 
abundance of the whales' primary prey, harbor seals, in nearshore 
waters. Population growth began slowing in the mid-1990s and has 
continued to slow in recent years (DFO, 2009). Population trends and 
status of this stock relative to its OSP level are currently unknown, 
as is the actual maximum productivity rate. Analyses in DFO (2009) 
estimated a rate of increase of about six percent per year from 1975 to 
2006, but this included recruitment of non-calf whales into the 
population. The default maximum net growth rate for cetaceans (4 
percent) is considered appropriate pending additional information 
(Carretta et al., 2011).
    The West Coast transient stock is a trans-boundary stock, with 
minimum counts for the population of transient killer whales coming 
from various photographic datasets. Combining these counts of cataloged 
transient whales gives an abundance estimate of 354 individuals for the 
West Coast transient stock (Allen and Angliss, 2011). Although this 
direct count of individually identifiable animals does not necessarily 
represent the number of live animals, it is considered a conservative 
minimum estimate (Allen and Angliss, 2011). However, the number in 
Washington waters at any one time is probably fewer than twenty 
individuals (Wiles, 2004). The West Coast transient killer whale stock 
is not designated as depleted under the MMPA or listed under the ESA. 
The estimated annual level of human-caused mortality and serious injury 
does not exceed the PBR. Therefore, the West Coast Transient stock of 
killer whales is not classified as a strategic stock.
    The estimated minimum mortality rate incidental to U.S. commercial 
fisheries is zero animals per year (Allen and Angliss, 2011). However, 
this could represent an underestimate as regards total fisheries-
related mortality due to a lack of data concerning marine mammal 
interactions in Canadian commercial fisheries known to have potential 
for interaction with killer whales. Any such interactions are thought 
to be few in number (Allen and Angliss, 2011). Other mortality, as a 
result of shootings or ship strikes, has been of concern in the past. 
However, no ship strikes have been reported for this stock, and 
shooting of transients is thought to be minimal because their diet is 
based on marine mammals rather than fish. There are no reports of a 
subsistence harvest of killer whales in Alaska or Canada.
    Transient occurrence in inland waters appears to peak during August 
and September which is the peak time for harbor seal pupping, weaning, 
and post-weaning (Baird and Dill, 1995). The number of west coast 
transients in Washington inland waters at any one time was considered 
likely to be fewer than twenty individuals by Wiles (2004), although 
more recent information (2004-10) suggests that transient use of inland 
waters has increased, possibly due to increasing prey abundance 
(Houghton et al., in prep.). However, Sinclair Inlet is a shallow bay 
located approximately eight miles through various waterways from the 
main open waters of Puget Sound, where killer whales occur more 
frequently, and killer whale occurrence in Sinclair Inlet is uncommon. 
From December 2002 to January 2013, there were two reports of transient 
killer whales transiting through the area around NBKB, with both 
reports occurring in May (a group of up to 12 in 2004 and a group of up 
to 5 in 2012; www.orcanetwork.org).

Gray Whale

    Gray whales are found in shallow coastal waters, migrating between 
summer feeding areas in the north and winter breeding areas in the 
south. Gray whales were historically common throughout the northern 
hemisphere but are now found only in the Pacific, where two populations 
are recognized, Eastern and Western North Pacific (ENP and WNP). ENP 
whales breed and calve primarily in areas off Baja California and in 
the Gulf of California. From February to May, whales typically migrate 
northbound to summer/fall feeding areas in the Chukchi and northern 
Bering Seas, with the southbound return to calving areas typically 
occurring in November and December. WNP whales are known to feed in the 
Okhotsk Sea and off of Kamchatka before migrating south to poorly known 
wintering grounds, possibly in the South China Sea.
    The two populations have historically been considered 
geographically isolated from each other; however, recent data from 
satellite-tracked whales indicates that there is some overlap between 
the stocks. Two WNP whales were tracked from Russian foraging areas 
along the Pacific rim to Baja California (Mate et al., 2011), and, in 
one case where the satellite tag remained attached to the whale for a 
longer period, a WNP whale was tracked from Russia to Mexico and back 
again (IWC, 2012). Between 22-24 WNP whales are known to have occurred 
in the eastern Pacific through comparisons of ENP and WNP photo-
identification catalogs (IWC, 2012; Weller et al., 2011; Burdin et al., 
2011), and WNP animals comprised 8.1 percent of gray whales identified 
during a recent field season off of Vancouver Island (Weller et al., 
2012). In addition, two genetic matches of WNP whales have been 
recorded off of Santa Barbara, CA (Lang et al., 2011a). Therefore, a 
portion of the WNP population is assumed to migrate, at least in some 
years, to the eastern Pacific during the winter breeding season. 
However, no WNP whales are known to have occurred in Washington inland 
waters. The likelihood of any gray whale being exposed to project sound 
to the degree considered in this document is already low, given the 
uncommon occurrence of gray whales in the project area. In the event 
that a gray whale did occur in the project area, it is extremely 
unlikely that it would be one of the approximately twenty WNP whales 
that have been documented in the eastern Pacific (less than one percent 
probability). The likelihood that a WNP whale would be present in the 
action area is insignificant and discountable.
    In addition, recent studies provide new information on gray whale 
stock structure within the ENP, with emphasis on whales that feed 
during summer off the Pacific coast between northern California and 
southeastern Alaska, occasionally as far north as Kodiak Island, Alaska 
(Gosho et al., 2011). These whales, collectively known as the Pacific 
Coast Feeding Group (PCFG), are a trans-boundary population

[[Page 56669]]

with the U.S. and Canada and are defined by the International Whaling 
Commission (IWC) as follows: gray whales observed between June 1 to 
November 30 within the region between northern California and northern 
Vancouver Island (from 41[deg] N to 52[deg] N) and photo-identified 
within this area during two or more years (Carretta et al., 2013). 
Photo-identification and satellite tagging studies provide data on 
abundance, population structure, and movements of PCFG whales 
(Calambokidis et al., 2010; Mate et al; 2010; Gosho et al., 2011). 
These data in conjunction with genetic studies (e.g., Frasier et al., 
2011; Lang et al., 2011b) indicate that the PCFG may be a 
demographically distinct feeding aggregation, and may warrant 
consideration as a distinct stock (Carretta et al., 2013). Therefore, 
abundance for the PCFG (as a component of the broader ENP stock) was 
calculated by NMFS. It is unknown whether PCFG whales would be 
encountered in Washington inland waters.
    The ENP population of gray whales, which is managed as a stock, was 
removed from ESA protection in 1994, is not currently protected under 
the ESA, and is not listed as depleted under the MMPA. Punt and Wade 
(2010) estimated the ENP population was at 91 percent of carrying 
capacity and at 129 percent of the maximum net productivity level and 
therefore within the range of its optimum sustainable population. The 
ENP stock of gray whales is not classified as a strategic stock under 
the MMPA because the estimated annual level of human-caused mortality 
(128) is less than the calculated PBR (558) (Carretta et al., 2013). 
PCFG whales do not currently have a formal status under the MMPA, 
although the estimated annual level of human-caused mortality (0.6) is 
less than the calculated PBR (2.8) (Carretta et al., 2013). The WNP 
population is listed as endangered under the ESA and depleted under the 
MMPA as a foreign stock.
    The best abundance estimate of the ENP stock of gray whales is 
19,126 (CV = 0.071) and the minimum population size of this stock is 
18,017 individuals (Carretta et al., 2013). Systematic counts of gray 
whales migrating south along the central California coast have been 
conducted by shore-based observers since 1967. The best and minimum 
abundance estimates were calculated from 2006-07 survey data, the first 
year in which improved counting techniques and a more consistent 
approach to abundance estimation were used (Carretta et al., 2013). The 
population size of the ENP gray whale stock has been increasing over 
the past several decades despite a west coast UME (unexplained causes) 
from 1999-2001. The estimated annual rate of increase from 1967-88, 
based on the revised abundance time series from Laake et al. (2009), is 
3.2 percent (Punt and Wade, 2010). Based on the same analyses, the best 
estimate of the maximum productivity rate for gray whales is considered 
to be 6.2 percent. The best abundance estimate for PCFG whales is 194 
(SE = 17.0), as determined through photographic mark-recapture studies 
(Calambokidis et al., 2010). The most recent estimate of WNP gray whale 
abundance is 137 individuals (IWC, 2012).
    As noted above, gray whale numbers were significantly reduced by 
whaling, becoming extirpated from the Atlantic by the early 1700s and 
listed as an endangered species in the Pacific. The ENP stock has since 
recovered sufficiently to be delisted from the ESA. Gray whales remain 
subject to occasional fisheries-related mortality and death from ship 
strikes. Based on stranding network data for the period 2006-10, there 
are an average of 0.2 deaths per year from the former and 2.2 per year 
from the latter. In addition, subsistence hunting of gray whales by 
hunters in Russia and the U.S. is approved by the IWC, although none is 
currently authorized in the U.S. From 2006-10, the annual Russian 
subsistence harvest was 123 whales (Carretta et al., 2013). Climate 
change is considered a significant habitat concern for gray whales, as 
prey composition and distribution is likely to be altered and human 
activity in the whales' summer feeding grounds increases (Carretta et 
al., 2013).
    Gray whales generally migrate southbound past Washington in late 
December and January, and transit past Washington on the northbound 
return in March to May. Gray whales do not generally make use of 
Washington inland waters, but have been observed in certain portions of 
those waters in all months of the year, with most records occurring 
from March through June (Calambokidis et al., 2010; 
www.orcanetwork.org) and associated with regular feeding areas. Usually 
fewer than twenty gray whales visit the inner marine waters of 
Washington and British Columbia beginning in about January, with some 
staying until summer. Six to ten of these are PCFG whales that return 
most years to feeding sites near Whidbey and Camano Islands in northern 
Puget Sound. The remaining individuals occurring in any given year 
generally appear unfamiliar with feeding areas, often arrive emaciated, 
and commonly die of starvation (WDFW, 2012). From December 2002 to 
January 2013, the Orca Network sightings database reports four 
occurrences of gray whales in the project area during the in-water work 
window (www.orcanetwork.org). Three sightings occurred during the 
winter of 2008-09, and one stranding was reported in January 2013. The 
necropsy of the whale indicated that it was a juvenile male in poor 
nutritional health. Two other strandings have been recorded in the 
project area, in May 2005 and July 2011.

Potential Effects of the Specified Activity on Marine Mammals

    We have determined that pile driving, as outlined in the project 
description, has the potential to result in behavioral harassment of 
marine mammals that may be present in the project vicinity while 
construction activity is being conducted. In theory, impact pile 
driving could result in injury of marine mammals although, for reasons 
described later in this document, we do not believe such an outcome to 
be likely or even possible in some cases. The full range of potential 
effects of sound on marine mammals, and pile driving in particular, are 
described in this section.

Marine Mammal Hearing

    Effects on marine mammals anticipated from the specified activities 
would be expected to result primarily from exposure of animals to 
underwater sound. 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 (Richardson et al., 1995; Wartzok and Ketten, 
1999). 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):

[[Page 56670]]

     Low-frequency cetaceans (mysticetes): Functional hearing 
is estimated to occur between approximately 7 Hz and 30 kHz (extended 
from 22 kHz on the basis of data indicating some mysticetes can hear 
above 22 kHz; 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): 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 40 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 (Hemila 
et al., 2006; Mulsow et al., 2011).
    Three pinniped and two cetacean species could potentially occur in 
the proposed project area during the project timeframe. The harbor seal 
is a phocid species, while both sea lions are otariid species. Of the 
cetacean species that may occur in the project area, the killer whale 
is classified as mid-frequency and the gray whale is classified as low-
frequency (Southall et al., 2007).

Underwater Sound Effects

    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., 2003; 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 may 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, ranging from effects such as behavioral disturbance, 
tactile perception, physical discomfort, slight injury of the internal 
organs and the auditory system, to mortality (Yelverton et al., 1973).
    Hearing Impairment and Other Physical Effects--Marine mammals 
exposed to high intensity sound repeatedly or for prolonged periods can 
experience hearing threshold 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, in the unlikely event that it occurred, would constitute injury, 
but TTS is not considered injury (Southall et al., 2007). It is 
unlikely that the project would result in any cases of temporary or 
especially permanent hearing impairment or any significant non-auditory 
physical or physiological effects for reasons discussed later in this 
document. Some behavioral disturbance is expected, but it is likely 
that this would be localized and short-term because of the short 
project duration.
    Several aspects of the planned monitoring and mitigation measures 
for this project (see the ``Proposed Mitigation'' and ``Proposed 
Monitoring and Reporting'' sections later in this document) are 
designed to detect marine mammals occurring near the pile driving to 
avoid exposing them to sound pulses that might, in theory, cause 
hearing impairment. In addition, many cetaceans are likely to show some 
avoidance of the area where received levels of pile driving sound are 
high enough that hearing impairment could potentially occur. In those 
cases, the avoidance responses of the animals themselves would reduce 
or (most likely) avoid any possibility of hearing impairment. Non-
auditory physical effects may also occur in marine mammals exposed to 
strong underwater pulsed sound. It is especially unlikely that any 
effects of these types would occur during the present project given the 
brief duration of exposure for any given individual and the planned 
monitoring and mitigation measures. 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

[[Page 56671]]

approximately 186 dB re 1 [mu]Pa\2\-s (i.e., 186 dB sound exposure 
level [SEL] or approximately 221-226 dB pk-pk) in order to produce 
brief, mild TTS. Exposure to several strong pulses that each have 
received levels near 190 dB re 1 [mu]Pa 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. 
Levels greater than or equal to 190 dB re 1 [mu]Pa rms are expected to 
be restricted to radii no more than 5 m (16 ft) from the pile driving. 
For an odontocete closer to the surface, the maximum radius with 
greater than or equal to 190 dB re 1 [mu]Pa rms would be smaller.
    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). To avoid the potential for 
injury, NMFS' current policy is that cetaceans should not be exposed to 
pulsed underwater sound at received levels exceeding 180 dB re 1 [mu]Pa 
rms. 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 pile driving activity might incur TTS, there has been 
further speculation about the possibility that some individuals 
occurring very close to pile driving 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 re 1 [mu]Pa at 1 m. 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 re 1 
[mu]Pa, 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 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

[[Page 56672]]

marine mammals to loud pulsed sound sources (typically seismic guns or 
acoustic harassment devices, but also including impact 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 non-pulsed sources, such as 
vibratory pile installation, have not been documented as well as 
responses to pulsed sounds.
    With both types of pile driving, it is likely that the onset of 
pile driving could result in temporary, short term changes in an 
animal's typical behavior and/or avoidance of the affected area. These 
behavioral changes may include (Richardson et al., 1995): changing 
durations of surfacing and dives, number of blows per surfacing, or 
moving direction and/or speed; reduced/increased vocal activities; 
changing/cessation of certain behavioral activities (such as 
socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping); avoidance of 
areas where sound sources are located; and/or flight responses (e.g., 
pinnipeds flushing into water from haul-outs or rookeries). Since pile 
driving would likely only occur for a few hours a day, over a short 
period of time, it is unlikely to result in permanent displacement. Any 
potential impacts from pile driving activities could be experienced by 
individual marine mammals, but would not be likely to cause population 
level impacts, or affect the long-term fitness of the species.
    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 be causing 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 have less effect on high frequency 
echolocation sounds made by porpoises. However, lower frequency man-
made sounds are more likely to 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 population, 
community, or even ecosystem 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. However, much 
of the sound from the proposed activities is confined in an area of 
inland waters (Sinclair Inlet) that is bounded by landmass and far 
removed from more open waters of Puget Sound; therefore, the sound 
generated is not expected to contribute significantly to increased 
ocean ambient sound.
    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 the duration of the driving 
event. The probability for impact pile driving resulting from this 
proposed action masking acoustic signals important to the behavior and 
survival of marine mammal species is likely to be discountable. 
Vibratory pile driving is also relatively short-term, with rapid 
oscillations occurring for the duration of the driving event, which is 
likely to be short for this project. It is possible that vibratory pile 
driving resulting from this proposed action may mask acoustic signals 
important to the behavior and survival of marine mammal species, but 
the short-term duration and limited affected area would result in 
insignificant impacts from masking. Any masking event that could 
possibly rise to Level B harassment under the MMPA would occur 
concurrently within the zones of behavioral harassment already 
estimated for vibratory and impact pile driving, and which have already 
been taken into account in the exposure analysis.

Airborne Sound Effects

    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 pile driving sound would have less impact on 
cetaceans than pinnipeds because sound from atmospheric sources does 
not transmit well underwater (Richardson et al., 1995);

[[Page 56673]]

thus, airborne sound would only be an issue for pinnipeds in the 
project area, whether hauled-out or in the water with heads in the air. 
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 NBKB would not result in permanent 
impacts to habitats used directly by marine mammals, but may have 
potential short-term impacts to food sources such as forage fish and 
salmonids, and may affect acoustic habitat (see masking discussion 
above). There are no rookeries or major haul-out sites, no known 
foraging hotspots, or other ocean bottom structure of significant 
biological importance to marine mammals present in the marine waters in 
the vicinity of the project area. Therefore, the main impact issue 
associated with the proposed activity would be temporarily elevated 
sound levels and the associated direct effects on marine mammals, as 
discussed previously 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 NBKB and minor impacts to the immediate 
substrate during installation and removal of piles during the pier 
maintenance project.

Pile Driving Effects on Potential Prey (Fish)

    Construction activities may produce both pulsed (i.e., impact pile 
driving) and continuous (i.e., vibratory pile driving) 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) and Hastings (2009) identified several studies that 
suggest fish may relocate to avoid certain areas of sound energy. 
Additional studies have documented effects of pile driving (or other 
types of sounds) on fish, although several are based on studies in 
support of large, multiyear bridge construction projects (e.g., Scholik 
and Yan, 2001, 2002; Popper and Hastings, 2009). Sound pulses at 
received levels of 160 dB re 1 [mu]Pa may cause subtle changes in fish 
behavior. SPLs of 180 dB may cause noticeable changes in behavior 
(Pearson et al., 1992; Skalski et al., 1992). SPLs of sufficient 
strength have been known to cause injury to fish and fish mortality. 
The most likely impact to fish from pile driving activities at the 
project area would be temporary behavioral avoidance of the area. The 
duration of fish avoidance of this area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. In general, impacts to marine mammal prey 
species are expected to be minor and temporary due to the short 
timeframe for the project. However, adverse impacts may occur to a few 
species of fish which may still be present in the project area despite 
operating in a reduced work window in an attempt to avoid important 
fish spawning time periods.

Pile Driving Effects on Potential Foraging Habitat

    The area likely impacted by the project is relatively small 
compared to the available habitat in inland waters in the region. 
Avoidance by potential prey (i.e., fish) of the immediate area due to 
the temporary loss of this foraging habitat is also possible. The 
duration of fish avoidance of this area after pile driving stops is 
unknown, but a rapid return to normal recruitment, distribution and 
behavior is anticipated. Any behavioral avoidance by fish of the 
disturbed area would still leave significantly large areas of fish and 
marine mammal foraging habitat in the nearby vicinity.
    Given the short daily duration of sound associated with individual 
pile driving events and the relatively small areas being 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. Therefore, pile driving is not likely to have a 
permanent, adverse effect on marine mammal foraging habitat at the 
project area. The area around NBKB, including the adjacent ferry 
terminal and nearby marinas, is heavily altered with significant levels 
of industrial and recreational activity, and is unlikely to harbor 
significant amounts of forage fish.

Proposed Mitigation

    In order to issue an incidental take authorization (ITA) under 
section 101(a)(5)(D) of the MMPA, we 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 (where relevant).
    Measurements from proxy pile driving events were coupled with 
practical spreading loss to estimate zones of influence (ZOIs; see 
``Estimated Take by Incidental Harassment''); these values were used to 
develop mitigation measures for pile driving activities at NBKB. The 
ZOIs effectively represent the mitigation zone that would be 
established around each pile to prevent Level A harassment to marine 
mammals, while providing estimates of the areas within which Level B 
harassment might occur. In addition to the specific measures described 
later in this section, the Navy would conduct briefings between 
construction supervisors and crews, marine mammal monitoring team, and 
Navy staff prior to the start of all pile driving activity, and when 
new personnel join the work, in order to explain responsibilities, 
communication procedures, marine mammal monitoring protocol, and 
operational procedures.

Monitoring and Shutdown for Pile Driving

    The following measures would apply to the Navy's mitigation through 
shutdown and disturbance zones:
    Shutdown Zone--For all pile driving and removal activities, the 
Navy will establish a shutdown zone intended to contain the area in 
which SPLs equal or exceed the 190 dB rms acoustic injury criteria. The 
purpose of a shutdown zone is to define an area within which shutdown 
of activity would occur upon sighting of a marine mammal (or in 
anticipation of an animal entering the defined area), thus preventing 
injury, serious injury, or death of marine mammals. Radial distances 
for shutdown zones are shown in Table 3. However, a minimum shutdown 
zone of 10 m (which is larger than the maximum predicted injury zone) 
will be established during all pile driving activities, regardless of 
the estimated zone. Vibratory pile driving activities are not predicted 
to produce sound exceeding the Level A standard, but these 
precautionary measures are intended to prevent the already unlikely 
possibility of physical interaction with construction equipment and to 
further reduce any possibility of acoustic injury.
    Disturbance Zone--Disturbance zones are the areas in which SPLs 
equal or

[[Page 56674]]

exceed 160 and 120 dB rms (for pulsed and non-pulsed sound, 
respectively). Disturbance zones provide utility for monitoring 
conducted for mitigation purposes (i.e., shutdown zone monitoring) by 
establishing monitoring protocols for areas adjacent to the shutdown 
zones. Monitoring of disturbance zones enables observers to be aware of 
and communicate the presence of marine mammals in the project area but 
outside the shutdown zone and thus prepare for potential shutdowns of 
activity. However, the primary purpose of disturbance zone monitoring 
is for documenting incidents of Level B harassment; disturbance zone 
monitoring is discussed in greater detail later (see ``Proposed 
Monitoring and Reporting''). Nominal radial distances for disturbance 
zones are shown in Table 3.
    In order to document observed incidences of harassment, monitors 
record all marine mammal observations, regardless of location. The 
observer's location, as well as the location of the pile being driven, 
is known from a GPS. The location of the animal is estimated as a 
distance from the observer, which is then compared to the location from 
the pile. It may then be estimated whether the animal was exposed to 
sound levels constituting incidental harassment on the basis of 
predicted distances to relevant thresholds in post-processing of 
observational and acoustic data, and a precise accounting of observed 
incidences of harassment created. This information may then be used to 
extrapolate observed takes to reach an approximate understanding of 
actual total takes.
    Monitoring Protocols--Monitoring would be conducted before, during, 
and after pile driving activities. In addition, observers shall record 
all incidences of marine mammal occurrence, regardless of distance from 
activity, and shall document any behavioral reactions in concert with 
distance from piles being driven. Observations made outside the 
shutdown zone will not result in shutdown; that pile segment would be 
completed without cessation, unless the animal approaches or enters the 
shutdown zone, at which point all pile driving activities would be 
halted. Please see the Monitoring Plan (Appendix C in the Navy's 
application), developed by the Navy in agreement with NMFS, for full 
details of the monitoring protocols. Monitoring will take place from 15 
minutes prior to initiation through 30 minutes post-completion of pile 
driving activities. Pile driving activities include the time to remove 
a single pile or series of piles, as long as the time elapsed between 
uses of the pile driving equipment is no more than 30 minutes.
    The following additional measures apply to visual monitoring:
    (1) Monitoring will be conducted by qualified observers, who will 
be placed at the best vantage point(s) practicable to monitor for 
marine mammals and implement shutdown/delay procedures when applicable 
by calling for the shutdown to the hammer operator. Qualified observers 
are trained biologists, with the following minimum qualifications:
     Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the water's surface 
with ability to estimate target size and distance; use of binoculars 
may be necessary to correctly identify the target;
     Advanced education in biological science, wildlife 
management, mammalogy, or related fields (bachelor's degree or higher 
is required);
     Experience and ability to conduct field observations and 
collect data according to assigned protocols (this may include academic 
experience);
     Experience or training in the field identification of 
marine mammals, including the identification of behaviors;
     Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
     Writing skills sufficient to prepare a report of 
observations including but not limited to the number and species of 
marine mammals observed; dates and times when in-water construction 
activities were conducted; dates and times when in-water construction 
activities were suspended to avoid potential incidental injury from 
construction sound of marine mammals observed within a defined shutdown 
zone; and marine mammal behavior; 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 shutdown zone 
will be monitored for 15 minutes to ensure that it is clear of marine 
mammals. Pile driving will only commence once observers have declared 
the shutdown zone clear of marine mammals; animals will be allowed to 
remain in the shutdown zone (i.e., must leave of their own volition) 
and their behavior will be monitored and documented. The shutdown zone 
may only be declared clear, and pile driving started, when the entire 
shutdown zone is visible (i.e., when not obscured by dark, rain, fog, 
etc.). In addition, if such conditions should arise during impact pile 
driving that is already underway, the activity would be halted.
    (3) If a marine mammal approaches or enters the shutdown zone 
during the course of pile driving operations, activity will be halted 
and delayed until either the animal has voluntarily left and been 
visually confirmed beyond the shutdown zone or 15 minutes have passed 
without re-detection of the animal. Monitoring will be conducted 
throughout the time required to drive a pile.

Special Conditions

    The Navy has not requested the authorization of incidental take for 
Steller sea lions, killer whales, or gray whales (see discussion in 
Estimated Take by Incidental Harassment). Therefore, shutdown would be 
implemented in the event that a Steller sea lion or any cetacean is 
observed upon sighting within (or in anticipation of entering) the 
defined disturbance zone. As described later in this document, we 
believe that occurrence of any of these species during the in-water 
work window would be uncommon. For gray and killer whales, in 
particular, the occurrence of an individual or group would likely be 
highly noticeable and would attract significant attention in local 
media and with local whale watchers and interested citizens.
    Prior to the start of pile driving on any day, the Navy would 
contact and/or review the latest sightings data from the Orca Network 
and/or Center for Whale Research to determine the location of the 
nearest marine mammal sightings. The Orca Sightings Network consists of 
a list of over 600 residents, scientists, and government agency 
personnel in the U.S. and Canada, and includes passive acoustic 
detections. The presence of a killer whale or gray whale in the 
southern reaches of Puget Sound would be a notable event, drawing 
public attention and media scrutiny. With this level of coordination in 
the region of activity, the Navy should be able to effectively receive 
real-time information on the presence or absence of whales, sufficient 
to inform the day's activities. Pile removal or driving would not occur 
if there was the risk of incidental harassment of a species for which 
incidental take was not authorized.
    Prior to beginning pile driving on each day, monitors would scan 
the floating security barrier to ensure that no Steller sea lions are 
present. During vibratory pile removal, four land-based observers will 
monitor the area; these would be positioned with two at the

[[Page 56675]]

pier work site, one at the eastern extent of the ZOI in the Manette 
neighborhood of Bremerton, and one at the southern extent of the ZOI 
near the Annapolis ferry landing in Port Orchard (please see Figure 1 
of Appendix C in the Navy's application). Additionally, one vessel-
based observer will travel through the monitoring area, completing an 
entire loop approximately every 30 minutes. If any killer whales, grey 
whales, or Steller sea lions are detected, activity would not begin or 
would shut down.

Timing Restrictions

    In the project area, designated timing restrictions exist to avoid 
in-water work when salmonids and other spawning forage fish are likely 
to be present. The in-water work window is June 15-March 1. All in-
water construction activities would occur only during daylight hours 
(sunrise to sunset).

Soft Start

    The use of a soft-start procedure is believed to provide additional 
protection to marine mammals by warning or providing a chance to leave 
the area prior to the hammer operating at full capacity, and typically 
involves a requirement to initiate sound from vibratory hammers for 
fifteen seconds at reduced energy followed by a 30-second waiting 
period. This procedure is repeated two additional times. However, 
implementation of soft start for vibratory pile driving during previous 
pile driving work conducted by the Navy at another location has led to 
equipment failure and serious human safety concerns. Therefore, 
vibratory soft start is not proposed as a mitigation measure for this 
project, as we have determined it not to be practicable. We have 
further determined this measure unnecessary to providing the means of 
effecting the least practicable impact on marine mammals and their 
habitat. Prior to issuing any further IHAs to the Navy for pile driving 
activities in 2014 and beyond, we plan to facilitate consultation 
between the Navy and other practitioners (e.g., Washington State 
Department of Transportation and/or the California Department of 
Transportation) in order to determine whether the potentially 
significant human safety issue is inherent to implementation of the 
measure or is due to operator error. For impact driving, soft start 
will be required, and contractors will provide an initial set of three 
strikes from the impact hammer at 40 percent energy, followed by a 30-
second waiting period, then two subsequent three-strike sets.
    We have carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that we prescribe the means of effecting 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.
    Based on our evaluation of the applicant's proposed measures, as 
well as any other potential measures that may be relevant to the 
specified activity, we have preliminarily determined that the proposed 
mitigation measures provide the means of effecting the least 
practicable impact on marine mammal species or stocks and their 
habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an ITA for an activity, section 101(a)(5)(D) of 
the MMPA states that we 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 ITAs 
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. 
The Navy's proposed monitoring and reporting is also described in their 
Marine Mammal Monitoring Plan (Appendix C of the Navy's application).

Visual Marine Mammal Observations

    The Navy will collect sighting data and behavioral responses to 
construction for marine mammal species observed in the region of 
activity during the period of activity. All observers will be trained 
in marine mammal identification and behaviors and are required to have 
no other construction-related tasks while conducting monitoring. The 
Navy will monitor the shutdown zone and disturbance zone before, 
during, and after pile driving, with observers located at the best 
practicable vantage points. Based on our requirements, the Navy would 
implement the following procedures for pile driving:
     MMOs would be located at the best vantage point(s) in 
order to properly see the entire shutdown zone and as much of the 
disturbance zone as possible.
     During all observation periods, observers will use 
binoculars and the naked eye to search continuously for marine mammals.
     If the shutdown zones are obscured by fog or poor lighting 
conditions, pile driving at that location will not be initiated until 
that zone is visible. Should such conditions arise while impact driving 
is underway, the activity would be halted.
     The shutdown and disturbance zones around the pile will be 
monitored for the presence of marine mammals before, during, and after 
any pile driving or removal activity.
    During vibratory pile removal, four observers would be deployed as 
described under Proposed Mitigation, including four land-based 
observers and one-vessel-based observer traversing the extent of the 
Level B harassment zone. During impact driving, one observer would be 
positioned at or near the pile to observe the much smaller disturbance 
zone.
    Individuals implementing the monitoring protocol will assess its 
effectiveness using an adaptive approach. Monitoring biologists 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 the 
Navy.

Data Collection

    We require that observers use approved data forms. Among other 
pieces of information, the Navy will record detailed information about 
any implementation of shutdowns, including the distance of animals to 
the pile and description of specific actions that ensued and resulting 
behavior of the animal, if any. In addition, the Navy will attempt to 
distinguish between the number of individual animals taken and the 
number of incidences of take. We require that, at a minimum, the 
following information be collected on the sighting forms:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Weather parameters (e.g., percent cover, visibility);
     Water conditions (e.g., sea state, tide state);
     Species, numbers, and, if possible, sex and age class of 
marine mammals;

[[Page 56676]]

     Description of any observable marine mammal behavior 
patterns, including bearing and direction of travel, and if possible, 
the correlation to SPLs;
     Distance from pile driving activities to marine mammals 
and distance from the marine mammals to the observation point;
     Locations of all marine mammal observations; and
     Other human activity in the area.
     Description of implementation of mitigation measures 
(e.g., shutdown or delay).

Reporting

    A draft report would be submitted to NMFS within 45 days of the 
completion of marine mammal monitoring, or 60 days prior to the 
issuance of any subsequent IHA for this project, whichever comes first. 
The report will include marine mammal observations pre-activity, 
during-activity, and post-activity during pile driving days, and will 
also provide descriptions of any adverse responses to construction 
activities by marine mammals and a complete description of all 
mitigation shutdowns and the results of those actions and a refined 
take estimate based on the number of marine mammals observed during the 
course of construction. A final report would be prepared and submitted 
within 30 days following resolution of comments on the draft report.

Estimated Take by Incidental Harassment

    With respect to the activities described here, the MMPA defines 
``harassment'' as: ``Any act of pursuit, torment, or annoyance which 
(i) has the potential to injure a marine mammal or marine mammal stock 
in the wild [Level A harassment]; or (ii) has the potential to disturb 
a marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering [Level 
B harassment].'' All anticipated takes would be by Level B harassment, 
involving temporary changes in behavior. The proposed mitigation and 
monitoring measures are expected to minimize the possibility of 
injurious or lethal takes such that take by Level A harassment, serious 
injury, or mortality is considered discountable. However, it is 
unlikely that injurious or lethal takes would occur even in the absence 
of the proposed mitigation and monitoring measures.
    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 (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. 
In addition, it is often difficult to distinguish between the 
individuals 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.
    The project area is not believed to be particularly important 
habitat for marine mammals, nor is it considered an area frequented by 
marine mammals, although harbor seals may be present year-round and sea 
lions are known to haul-out on man-made objects at the NBKB waterfront. 
Sightings of other species are rare. Therefore, behavioral disturbances 
that could result from anthropogenic sound associated with these 
activities are expected to affect only a relatively small number of 
individual marine mammals, although those effects could be recurring 
over the life of the project if the same individuals remain in the 
project vicinity. The Navy has requested authorization for the 
incidental taking of small numbers of harbor seals and California sea 
lions in Sinclair Inlet and nearby waters that may be ensonified by 
project activities.

Marine Mammal Densities

    For all species, the best scientific information available was used 
to derive density estimates and the maximum appropriate density value 
for each species was considered for use in the marine mammal take 
assessment calculations. These values, shown in Table 7 below, were 
derived or confirmed by experts convened to develop such information 
for use in Navy environmental compliance efforts in the Pacific 
Northwest, including Washington inland waters. The Navy Marine Species 
Density Database (NMSDD) density estimates were recently finalized, and 
use data from local marine mammal data sets, expert opinion, and survey 
data from Navy biologists and other agencies. A technical report 
documenting methodologies used to derive these densities and relevant 
background data is still in development (DoN, in prep.). These data are 
generally considered the best available information for Washington 
inland waters, except where specific local abundance information is 
available. At NBKB, the Navy began collecting opportunistic 
observational data of animals hauled-out on the floating security 
barrier. These surveys began in February 2010 and have been conducted 
approximately monthly from September 2010 through present (DoN, 2013). 
In addition, the Washington State Department of Transportation (WSDOT) 
recently conducted in-water pile driving over the course of multiple 
work windows as part of the Manette Bridge construction project in the 
nearby Port Washington Narrows. WSDOT conducted required marine mammal 
monitoring as part of this project (WSDOT, 2011, 2012; Rand, 2011). We 
determined, for both harbor seals and California sea lions, that these 
sources of local abundance information comprise the best available data 
for use in the take assessment calculations, as described below.

   Table 7--Maximum Marine Mammal Density Estimates for NBKB (Sinclair
                                 Inlet)
------------------------------------------------------------------------
                                                       Density (Sinclair
                       Species                         Inlet), /
                                                             km\2\
------------------------------------------------------------------------
Harbor seal..........................................             0.4267
California sea lion..................................               0.13
Steller sea lion.....................................              0.037
Transient killer whale...............................             0.0024
Gray whale...........................................             0.0005
------------------------------------------------------------------------


[[Page 56677]]

Description of Take Calculation

    The take calculations presented here rely on the best data 
currently available for marine mammal populations in Puget Sound. The 
following assumptions are made when estimating potential incidences of 
take:
     All marine mammal individuals potentially available are 
assumed to be present within the relevant area, and thus incidentally 
taken;
     An individual can only be taken once during a 24-h period; 
and,
     There will be 20 total days of vibratory driving and 45 
days of impact pile driving.
     Exposures to sound levels above the relevant thresholds 
equate to take, as defined by the MMPA.
The calculation for marine mammal takes is estimated by:

Exposure estimate = (n * ZOI) * days of total activity

    Where:
n = density estimate used for each species/season
ZOI = sound threshold ZOI impact area; the area encompassed by all 
locations where the SPLs equal or exceed the threshold being 
evaluated
n * ZOI produces an estimate of the abundance of animals that could 
be present in the area for exposure, and is rounded to the nearest 
whole number before multiplying by days of total activity.

    The ZOI impact area is the estimated range of impact to the sound 
criteria. The distances specified in Table 3 and 5 were used to 
calculate ZOIs around each pile. The ZOI impact area calculations took 
into consideration the possible affected area with attenuation due to 
topographical constraints of Sinclair Inlet, and the radial distances 
to thresholds are not always reached.
    While pile driving can occur any day, and the analysis is conducted 
on a per day basis, only a fraction of that time (typically a matter of 
hours on any given day) is actually spent pile driving. The exposure 
assessment methodology is an estimate of the numbers of individuals 
exposed to the effects of pile driving activities exceeding NMFS-
established thresholds. Of note in these exposure estimates, mitigation 
methods (i.e., visual monitoring and the use of shutdown zones; soft 
start for impact pile driving) were not quantified within the 
assessment and successful implementation of mitigation is not reflected 
in exposure estimates. In addition, equating exposure with response 
(i.e., a behavioral response meeting the definition of take under the 
MMPA) is a simplistic and conservative assumption. For these reasons, 
results from this acoustic exposure assessment likely overestimate take 
estimates to some unquantifiable degree.
    Airborne Sound--No incidents of incidental take resulting solely 
from airborne sound are likely, as distances to the harassment 
thresholds will not reach areas where pinnipeds may haul out. Harbor 
seals can haul out at a variety of natural or manmade locations, but 
Navy waterfront surveys have found it rare for harbor seals to haul out 
along the NBKB waterfront (DoN, 2013). Individual sea lions are 
frequently observed hauled out on pontoons of the floating security 
fence within the restricted areas of NBKB, but this area is not within 
the airborne disturbance ZOI. We recognize that pinnipeds in the water 
could be exposed to airborne sound that may result in behavioral 
harassment when looking with heads above water. However, these animals 
will 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.
    Harbor Seal--While no harbor seal haul-outs are present in the 
action area or in the immediate vicinity of NBKB, haul-outs are present 
elsewhere in Sinclair Inlet and in other nearby waters and harbor seals 
may haul out on available objects opportunistically. Use of the NMSDD 
density value (0.4267 animals/km\2\; corrected for proportion of 
animals hauled-out at any given time) would result in an estimate of 2-
3 incidences of harassment per day; it is likely that this would not 
adequately represent the potential presence of harbor seals given 
observed occurrence at other nearby construction projects. Marine 
mammal monitoring conducted during pile driving work on the Manette 
Bridge showed variable numbers of harbor seals (but generally greater 
than indicated by the NMSDD density). During the first year of 
construction (in-water work window only), an average of 3.7 harbor 
seals were observed per day of monitoring with a maximum of 59 observed 
in October 2011 (WSDOT, 2011; Rand, 2011). During the most recent 
construction period (July-November 2012), an average of eleven harbor 
seals per monitoring day was observed, though some animals were likely 
counted multiple times (WSDOT, 2012). Given the potential for similar 
occurrence of harbor seals in the vicinity of NBKB during the in-water 
construction period, we determined it appropriate to use this most 
recent, local abundance information in the take assessment calculation.
    California Sea Lion--Similar to harbor seals, it is not likely that 
use of the NMSDD density value for California sea lions (0.13 animals/
km\2\) would adequately represent their potential occurrence in the 
project area. California sea lions are commonly observed hauled out on 
the floating security barrier which is in close proximity to Pier 6; 
counts from 34 surveys (March 2010-June 2013) showed an average of 42 
individuals per survey day (range 0-144; DoN, 2013). These counts 
represent the best local abundance data available and were used in the 
take assessment calculation.
    Steller Sea Lion--No Steller sea lion haul-outs are present within 
or near the action area, and Steller sea lions have not been observed 
during Navy waterfront surveys or during monitoring associated with the 
Manette Bridge construction project. It is assumed that the possibility 
exists that a Steller sea lion could occur in the project area, but 
there is no known attractant in Sinclair Inlet, which is a relatively 
muddy, industrialized area, and the floating security barrier that 
California sea lions use as an opportunistic haul-out cannot generally 
accommodate the larger adult Steller sea lions (juveniles could haul-
out on the barrier). Use of the NMSDD density estimate (0.037 animals/
km\2\) results in an estimate of zero exposures, and there are no 
existing data to indicate that Steller sea lions would occur more 
frequently locally. Therefore, the Navy has not requested the 
authorization of incidental take for Steller sea lions and we do not 
propose such authorization. The Navy would not begin activity or would 
shut down upon report of a Steller sea lion present within or 
approaching the relevant ZOI.
    Killer Whale--Transient killer whales are rarely observed in the 
project area, with records since 2002 showing one group transiting 
through the area in May 2004 and a subsequent, similar observation in 
May 2010. No other observations have occurred during Navy surveys or 
during project monitoring for Manette Bridge. Use of the NMSDD density 
estimate (0.0024 animals/km\2\) results in an estimate of zero 
exposures, and there are no existing data to indicate that killer 
whales would occur more frequently locally. Therefore, the Navy has not 
requested the

[[Page 56678]]

authorization of incidental take for transient killer whales and we do 
not propose such authorization. The Navy would not begin activity or 
would shut down upon report of a killer whale present within or 
approaching the relevant ZOI.
    Gray Whale--Gray whales are rarely observed in the project area, 
and the majority of in-water work would occur when whales are 
relatively less likely to occur (i.e., outside of March-May). Since 
2002 and during the in-water work window, there are observational 
records of three whales (all during winter 2008-09) and a stranding 
record of a fourth whale (January 2013). No other observations have 
occurred during Navy surveys or during project monitoring for Manette 
Bridge. Use of the NMSDD density estimate (0.0005 animals/km\2\) 
results in an estimate of zero exposures, and there are no existing 
data to indicate that gray whales would occur more frequently locally. 
Therefore, the Navy has not requested the authorization of incidental 
take for gray whales and we do not propose such authorization. The Navy 
would not begin activity or would shut down upon report of a gray whale 
present within or approaching the relevant ZOI.

     Table 8--Number of Potential Incidental Takes of Marine Mammals
------------------------------------------------------------------------
                       Species                         Exposure estimate
------------------------------------------------------------------------
Harbor seal\1\.......................................                715
California sea lion\2\...............................              2,730
Steller sea lion.....................................                  0
Transient killer whale...............................                  0
Gray whale...........................................                  0
------------------------------------------------------------------------
\1\ Use of NMSDD density results in estimated range of potential
  exposures of 130-195. Local abundance data were used in exposure
  assessment, i.e., 11 harbor seals potentially exposed per day for 65
  days of pile driving.
\2\ Use of NMSDD density results in estimated potential exposures of 65.
  Local abundance data were used in exposure assessment, i.e., 42
  California sea lions potentially exposed per day for 65 days of pile
  driving.

    For the Steller sea lion, transient killer whale, and gray whale, 
available information indicates that presence of these species is 
sufficiently rare to make exposure unlikely. Further, the Navy's 
proposed monitoring plan further mitigates any such possibility to the 
point that we consider it discountable and do not propose to authorize 
incidental take for these three species.

Negligible Impact and Small Numbers Analyses and Preliminary 
Determinations

    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.'' In making a negligible impact determination, we consider a 
variety of factors, including but not limited to: (1) The number of 
anticipated mortalities; (2) the number and nature of anticipated 
injuries; (3) the number, nature, intensity, and duration of Level B 
harassment; and (4) the context in which the take occurs.

Small Numbers Analysis

    The number of incidences of take proposed for authorization for 
harbor seals and California sea lions would be considered small 
relative to the relevant stocks or populations (less than five percent 
and one percent, respectively) even if each estimated taking occurred 
to a new individual. This is an extremely unlikely scenario as, for 
pinnipeds in estuarine/inland waters, there is likely to be some 
overlap in individuals present day-to-day.

Negligible Impact Analysis

    Pile driving activities associated with the Navy's pier maintenance 
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 
and removal. Potential takes could occur if individuals of these 
species are present in the ensonified zone when the specified activity 
is occurring.
    No injury, serious injury, or mortality is anticipated given the 
nature of the activity and measures designed to minimize the 
possibility of injury to marine mammals. The potential for these 
outcomes is minimized through the construction method and the 
implementation of the planned mitigation measures. Specifically, piles 
would be removed via vibratory means--an activity that does not have 
the potential to cause injury to marine mammals due to the relatively 
low source levels produced (less than 180 dB) and the lack of 
potentially injurious source characteristics--and, while impact pile 
driving produces short, sharp pulses with higher peak levels and much 
sharper rise time to reach those peaks, only small diameter concrete 
piles are planned for impact driving. Predicted source levels for such 
impact driving events are significantly lower than those typical of 
impact driving of steel piles and/or larger diameter piles. In 
addition, implementation of soft start and shutdown zones significantly 
reduces any possibility of injury. Given sufficient ``notice'' through 
use of soft start (for impact driving), marine mammals are expected to 
move away from a sound source that is annoying prior to its becoming 
potentially injurious. Environmental conditions in Sinclair Inlet are 
expected to generally be good, with calm sea states, although Sinclair 
Inlet waters may be more turbid than those further north in Puget Sound 
or in Hood Canal. Nevertheless, we expect conditions in Sinclair Inlet 
would allow a high marine mammal detection capability for the trained 
observers required, enabling a high rate of success in implementation 
of shutdowns to avoid injury, serious injury, or mortality. In 
addition, the topography of Sinclair Inlet should allow for placement 
of observers sufficient to detect cetaceans, should any occur (see 
Figure 1 of Appendix C in the Navy's application).
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from other 
similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring) (e.g., Thorson and Reyff, 
2006; HDR, Inc., 2012). Most likely, individuals will simply move away 
from the sound source and be temporarily displaced from the areas of 
pile driving, although even this reaction has been observed primarily 
only in association with impact pile driving. The pile driving 
activities analyzed here are similar to, or

[[Page 56679]]

less impactful than, numerous other construction activities conducted 
in San Francisco Bay and in the Puget Sound region, which have taken 
place with no reported injuries or mortality to marine mammals, and no 
known long-term adverse consequences from behavioral harassment. 
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 viability for the 
affected 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 area--
which is not believed to provide any habitat of special significance--
while the activity is occurring.
    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 significant 
habitat within the project area, including rookeries, significant haul-
outs, or known areas or features of special significance for foraging 
or reproduction; (4) the presumed efficacy of the proposed mitigation 
measures in reducing the effects of the specified activity to the level 
of least practicable impact. In addition, neither of these stocks are 
listed under the ESA or considered depleted under the MMPA. In 
combination, we believe that these factors, as well as the available 
body of evidence from other similar activities, demonstrate that the 
potential effects of the specified activity will have only short-term 
effects on individuals. The specified activity is not expected to 
impact rates of recruitment or survival and will therefore not result 
in population-level impacts.

Preliminary Determinations

    The number of marine mammals actually incidentally harassed by the 
project will depend on the distribution and abundance of marine mammals 
in the vicinity of the survey activity. However, we find that the 
number of potential takings proposed for authorization (by level B 
harassment only), which we consider to be a conservative, maximum 
estimate, is small relative to the relevant regional stock or 
population numbers, and that the effect of the activity will be 
mitigated to the level of least practicable impact through 
implementation of the mitigation and monitoring measures described 
previously. Based on the analysis contained herein of the likely 
effects of the specified activity on marine mammals and their habitat, 
we preliminarily find that the total taking from the activity will have 
a negligible impact on the affected species or stocks. Impact on 
Availability of Affected Species for Taking for Subsistence Uses
    There are no relevant subsistence uses of marine mammals implicated 
by this action. Therefore, we have preliminarily determined that the 
total taking of affected species or stocks would not have an 
unmitigable adverse impact on the availability of such species or 
stocks for taking for subsistence purposes.

Endangered Species Act (ESA)

    There are no ESA-listed marine mammals expected to occur in the 
action area. Therefore, the Navy has not requested authorization of the 
incidental take of ESA-listed species and no such authorization is 
proposed for issuance; therefore, no consultation under the ESA is 
required. National Environmental Policy Act (NEPA)
    The Navy has prepared a Draft Environmental Assessment (EA; Pier 6 
Pile Replacement Naval Base Kitsap) in accordance with NEPA and the 
regulations published by the Council on Environmental Quality. We have 
posted it on the NMFS Web site (see SUPPLEMENTARY INFORMATION) 
concurrently with the publication of this proposed IHA. NMFS will 
independently evaluate the EA and determine whether or not to adopt it. 
We may prepare a separate NEPA analysis and incorporate relevant 
portions of the Navy's EA by reference. Information in the Navy's 
application, EA, and this notice collectively provide the environmental 
information related to proposed issuance of the IHA for public review 
and comment. We will review all comments submitted in response to this 
notice as we complete the NEPA process, including a decision of whether 
to sign a Finding of No Significant Impact (FONSI), prior to a final 
decision on the IHA request.

Proposed Authorization

    As a result of these preliminary determinations, we propose to 
authorize the take of marine mammals incidental to the Navy's pier 
maintenance project, provided the previously mentioned mitigation, 
monitoring, and reporting requirements are incorporated.

    Dated: September 10, 2013.
Helen M. Golde,
Deputy Director, >Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2013-22294 Filed 9-12-13; 8:45 am]
BILLING CODE 3510-22-P