Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Test Pile Program, 4300-4322 [2011-1528]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 76, Number 16 (Tuesday, January 25, 2011)]
[Notices]
[Pages 4300-4322]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-1528]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA075


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a Test Pile Program

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 an application from the U.S. Navy (Navy) for 
an Incidental Harassment Authorization (IHA) to take marine mammals, by 
harassment, incidental to pile driving activities as part of a test 
pile program. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS 
is requesting comments on its proposal to issue an IHA to the Navy to 
take, by Level B Harassment only, five species of marine mammals during 
the specified activity.

DATES: Comments and information must be received no later than February 
24, 2011.

ADDRESSES: Comments on the application should be addressed to Michael 
Payne, Chief, Permits, Conservation and Education Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910-3225. The mailbox address for 
providing e-mail comments is ITP.Laws@noaa.gov. NMFS is not responsible 
for e-mail comments sent to addresses other than the one provided here. 
Comments sent via e-mail, including all attachments, must not exceed a 
10-megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to https://www.nmfs.noaa.gov/pr/permits/incidental.htm without change. All Personal Identifying Information 
(e.g., name, address) voluntarily submitted by the commenter may be 
publicly accessible. Do not submit Confidential Business Information or 
otherwise sensitive or protected information.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the address specified 
above, telephoning the contact listed below (see FOR FURTHER 
INFORMATION CONTACT), or visiting the internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm. The Navy has prepared a 
draft Environmental Assessment (EA) titled ``Test Pile Program NBK 
Bangor Waterfront, Naval Base Kitsap Bangor, Silverdale, WA'', and has 
prepared a draft Essential Fish Habitat Assessment titled ``Test Pile 
Program NBK Bangor Waterfront Draft Essential Fish Habitat 
Assessment''. These associated documents, prepared in compliance with 
the National Environmental Policy Act (NEPA) and Magnuson-Stevens 
Fishery Conservation and Management Act, respectively, are also 
available at the same internet address. Documents cited in this notice 
may also be viewed, by appointment, during regular business hours, at 
the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Ben Laws, Office of Protected 
Resources, NMFS, (301) 713-2289.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    Authorization for incidental takings shall be granted if NMFS finds 
that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 
as ``* * * an impact resulting from the specified activity that cannot 
be reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by

[[Page 4301]]

which citizens of the U.S. can apply for an authorization to 
incidentally take small numbers of marine mammals by harassment. 
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS review of 
an application followed by a 30-day public notice and comment period on 
any proposed authorizations for the incidental harassment of marine 
mammals. Within 45 days of the close of the comment period, NMFS must 
either issue or deny the authorization.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as:

    Any act of pursuit, torment, or annoyance which (i) has the 
potential to injure a marine mammal or marine mammal stock in the 
wild [Level A harassment]; or (ii) has the potential to disturb a 
marine mammal or marine mammal stock in the wild by causing 
disruption of behavioral patterns, including, but not limited to, 
migration, breathing, nursing, breeding, feeding, or sheltering 
[Level B harassment].

Summary of Request

    NMFS received an application on November 2, 2010 from the Navy for 
the taking of marine mammals incidental to pile driving in association 
with a test pile program in the Hood Canal at Naval Base Kitsap in 
Bangor, WA (NBKB). This test pile program is proposed to occur between 
July 16, 2011 and October 31, 2011. Six species of marine mammals may 
be present within the waters surrounding NBKB: Steller sea lions 
(Eumetopias jubatus), California sea lions (Zalophus californianus), 
harbor seals (Phoca vitulina), killer whales (Orcinus orca), Dall's 
porpoises (Phocoenoides dalli), and harbor porpoises (Phocoena 
phocoena). These species may occur year-round in the Hood Canal, with 
the exception of the Steller sea lion. Steller sea lions are present 
only from fall to late spring (November-June), outside of the project's 
timeline (July 16-October 31). Additionally, while the Southern 
Resident killer whale (listed as endangered under the Endangered 
Species Act [ESA]) is resident to the inland waters of Washington and 
British Columbia, it has not been observed in the Hood Canal in decades 
and was therefore excluded from further analysis. Only the five species 
which may be present during the project's timeline may be exposed to 
sound pressure levels associated with vibratory and impulsive pile 
driving, and will be analyzed in detail in this document.
    The Navy proposes to install up to 29 test and reaction piles at 
NBKB to gather geotechnical and noise data to validate the design 
concept for the building of a new Explosive Handling Wharf (EHW-2), as 
well as for future projects at the NBKB waterfront. The test pile 
program will require a maximum of forty work days for completion. The 
forty work day duration of the program includes the time for the 
initial pile installations, time for performing loading tests, and time 
to remove all of the test piles. The pile lengths will range from 100-
197 ft (30-60 m), and range in diameter from 30-60 in (0.8-1.5 m). The 
test pile program will involve driving eighteen steel pipe piles, at 
pre-determined locations within the proposed footprint of EHW-2. Some 
of the initial eighteen piles will be removed and re-driven as part of 
lateral load and tension tests. A total of eleven piles will be 
installed to perform lateral load and tension load tests. All piles 
will be driven with a vibratory hammer for their initial embedment 
depths, and select piles will be impact driven for their final 10-15 ft 
(3-4.6 m) for proofing. ``Proofing'' involves driving a pile the last 
few feet into the substrate to determine the capacity of the pile. The 
capacity during proofing is established by measuring the resistance of 
the pile to a hammer that has a piston with a known weight and stroke 
(distance the hammer rises and falls) so that the energy on top of the 
pile can be calculated. The blow count in ``blows per inch'' is 
measured to verify resistance, and pile compression capacities are 
calculated using a known formula. Noise attenuation measures (i.e., 
bubble curtain) will be used during all impact hammer operations and on 
two of the vibratory-driven piles. Hydroacoustic monitoring will be 
performed to assess effectiveness of noise attenuation measures.
    For pile driving activities, the Navy used NMFS-promulgated 
thresholds for assessing pile driving impacts (NMFS 2005b, 2009), 
outlined later in this document. The Navy used recommended spreading 
loss formulas (the practical spreading loss equation for underwater 
sounds and the spherical spreading loss equation for airborne sounds) 
and empirically-measured source levels from other 30-72 in (0.8-1.8 m) 
diameter steel pile driving events to estimate potential marine mammal 
exposures. Predicted exposures are outlined later in this document. The 
calculations predict that no Level A harassments would occur associated 
with pile driving activities, and that 1,180 Level B harassments may 
occur during the test pile program from underwater sound. No incidents 
of harassment were predicted from airborne sounds associated with pile 
driving. Some assumptions (including marine mammal densities and other 
assumptions) used to estimate the exposures are conservative, and may 
overestimate the potential number of exposures and their severity.

Description of the Specified Activity

    NBKB is located on the Hood Canal approximately twenty miles (32 
km) west of Seattle, WA (see Figures 1-1 and 1-2 in the Navy's 
application). NBKB provides berthing and support services to Navy 
submarines and other fleet assets. The entirety of NBKB, including the 
land areas and adjacent water areas in the Hood Canal are restricted 
from general public access. The Navy proposes a test pile program to 
support the design of the future construction of EHW-2. The proposed 
actions with the potential to affect marine mammals within the 
waterways adjacent to NBKB that could result in harassment under the 
MMPA are vibratory and impulsive pile driving operations associated 
with the test pile program. The proposed pile driving activities will 
occur between July 16, 2011 and October 31, 2011. All in-water 
construction activities within the Hood Canal are only permitted during 
July 16-February 15 in order to protect spawning fish populations. The 
further restriction of in-water work window proposed by the Navy avoids 
the possibility of incidental harassment of Steller sea lions. The 
Eastern Distinct Population Segment (DPS) of Steller sea lions, present 
in the Hood Canal outside of the proposed project time period, is 
listed as threatened under the ESA.
    As part of the Navy's sea-based strategic deterrence mission, the 
Navy Strategic Systems Programs directs research, development, 
manufacturing, test, evaluation, and operational support of the TRIDENT 
Fleet Ballistic Missile program. Maintenance and development of 
necessary facilities for handling of explosive materials is part of 
these duties. The proposed action for this IHA request is to install 
and remove up to 29 test and reaction piles, conduct loading tests on 
select piles, and measure in-water sound propagation parameters (e.g., 
transmission loss) during pile installation and removal. Geotechnical 
and sound propagation data collected during pile installation and 
removal will be integrated into the design, construction, and 
environmental planning for the Navy's proposed EHW-2. Future 
construction projects at the NBKB waterfront may also benefit from the 
geotechnical data gathered for use in their environmental planning 
documentation. The Navy proposes to install the test piles in the 
location planned for the future EHW-2, which will be adjacent to the 
existing

[[Page 4302]]

Explosive Handling Wharf (EHW-1) at NBKB. The test pile program will 
require a maximum of forty work days for completion. Hydroacoustic 
monitoring will be undertaken to assess the effectiveness of noise 
attenuation measures. The presence of marine mammals will also be 
monitored during pile installation and removal.
    The test pile program has been designed to collect adequate 
geotechnical and sound propagation data. Under the proposed action, the 
Navy will install 29 test and reaction piles in the Hood Canal. The 
pile lengths will range from 100-197 ft (30-60 m), and range in 
diameter from 30-60 in (0.8-1.5 m). All piles will subsequently be 
removed at the completion of the test pile program. These test piles 
will be situated throughout the footprint of the future EHW-2, 
currently in the preliminary planning process. Figure 1-3 of the Navy's 
application shows in detail the locations of each of the test piles.
    The installation of the test piles will involve driving eighteen 
steel pipe piles into the substrate. Additionally, three lateral load 
and two tension load tests will be performed. The lateral load test 
involves measurements of lateral displacement versus load for the 
piles. The lateral load tests will require re-installing two 60-in (1.5 
m) diameter piles and one 48-in (1.2 m) diameter pile. The tension load 
test measures the vertical capacity of a pile. The tension load tests 
will require driving four reaction piles for each of the two tension 
load tests. The lateral load test in combination with the tension load 
test will result in the installation of an additional eleven piles. The 
Navy expects that some of the initial eighteen test piles will be 
removed and re-driven as part of lateral load and tension tests. Please 
see the Navy's application for a diagram of the lateral load and 
tension load tests, and for more specific information regarding each 
test pile (Figure 1-4 and Table 1-1 of the Navy's application, 
respectively).
    According to the Navy, previous soil boring studies, as well as 
experience at EHW-1, confirms that the substrate appears to be 
relatively consistent in nature across the site. Therefore, all of the 
piles will be driven by a vibratory hammer to their initial embedment 
depths. The eighteen test piles would likely require the use of an 
impact hammer to drive the piles the remaining 10-15 ft (3-4.6 m) into 
the substrate and for proofing. The impact driver will perform a few 
blows to warm up the hammer and a number of blows to verify capacity. A 
Pile Dynamic Analyzer will be utilized to confirm capacity. As a 
contingency, any piles that cannot be driven to their desired depth 
using the vibratory hammer may require the use of the impact hammer to 
finish installation. This contingency has been accounted for in the 
modeling analysis.
    The contractor is expected to mobilize two floating barges, one 
large barge up to 80 ft wide x 300 ft (24 x 91 m) long and one medium 
sized barge approximately 60 ft wide x 150 ft (18 x 46 m) long, for the 
test pile program. These barges will be moved into location with a 44 
ft (13 m) tug boat. The two barges will share the work load, with the 
smaller barge working the inboard test piles and the larger barge 
working the outboard test piles. The smaller barge will likely be on 
site for approximately two weeks of pile driving while the larger barge 
will be on site for the full duration of the program which is expected 
to be no longer than forty days. Only one pile driving rig will be 
operated at a time.
    Sound attenuation measures (e.g., bubble curtain) will be used 
during all impact hammer operations, and on two of the vibratory-driven 
piles, to test the practicability of using bubble curtains with a 
vibratory hammer. The Navy will monitor hydroacoustic levels, as well 
as the presence and behavior of marine mammals during pile installation 
and removal. All piles will be removed at or before the completion of 
the test pile program because they could pose a potential navigation 
risk if left in place. Removal is also necessary because the test piles 
will not be incorporated into the proposed EHW-2, as exact pile 
locations for the future structure have not yet been finalized.
    The test pile program will require a maximum of forty work days for 
completion. A work day is limited to the hours from two hours post-
sunrise to two hours prior to sunset. The forty work day duration of 
the program includes the time for the initial pile installations, time 
for performing the loading tests, and time to remove all of the test 
piles. A 108-day authorization window (16 July-31 October) was 
requested to take into account delays that could occur due to the 
permitting process, materials availability, and inclement weather that 
may preclude construction.
    The Navy's contractor estimates that pile installation could occur 
at a maximum rate of four piles per day. However, the Navy anticipates 
that an average of two piles will be installed and removed per day. For 
each pile installed, the driving time is expected to include no more 
than one hour for vibratory driving and fifteen minutes for the impact 
driving portion of the project, with a maximum 100 blows executed per 
day. The U.S. Fish and Wildlife Service (USFWS) requested that a 
maximum of 100 blows be executed per day in order to minimize potential 
injurious impacts to fish species which the marbled murrelet, listed as 
threatened under the ESA, prey upon. All piles will be extracted using 
a vibratory hammer. Extraction is anticipated to take approximately 
thirty minutes per pile. Overall, this results in an estimated maximum 
of two hours for driving and removal per pile, or approximately four 
hours per day. Therefore, while forty days of total in-water work time 
is proposed, only a fraction of the total work time will actually be 
spent on pile driving and removal.
    An average work day (two hours post-sunrise to two hours prior to 
sunset) ranges from six to twelve hours (for an average of 
approximately eight to nine hours), depending on the month. Although it 
is anticipated that only four hours would need to be spent on pile 
driving and removal per day, the Navy modeled potential impacts as if 
the entire day (i.e., eight to nine hours) could be spent pile driving 
to take into account deviations from the estimated times for pile 
installation and removal and to account for the additional use of the 
impact pile driver in case of failure of the vibratory hammer to reach 
the desired embedment depth. Based on the proposed action, the total 
pile driving time from vibratory or impact pile driving would be less 
than fifteen days (29 piles at an average of two per day, assuming an 
average of eight to nine hours of pile driving per day).

Description of Noise Sources

    Underwater sound levels are comprised of multiple sources, 
including physical noise, biological noise, and anthropogenic noise. 
Physical noise includes waves at the surface, earthquakes, ice, and 
atmospheric noise. Biological noise includes sounds produced by marine 
mammals, fish, and invertebrates. Anthropogenic noise consists of 
vessels (small and large), dredging, aircraft overflights, and 
construction noise. Known noise levels and frequency ranges associated 
with anthropogenic sources similar to those that would be used for this 
project are summarized in Table 1. Details of each of the sources are 
described in the following text.

[[Page 4303]]



                          Table 1--Representative Noise Levels of Anthropogenic Sources
----------------------------------------------------------------------------------------------------------------
                                            Frequency   Underwater noise level (dB
               Noise source                range (Hz)         re 1 [micro]Pa)                 Reference
----------------------------------------------------------------------------------------------------------------
Small vessels............................   250-1,000  151 dB root mean square       Richardson et al. 1995.
                                                        (rms) at 1 m.
Tug docking gravel barge.................   200-1,000  149 dB rms at 100 m (328 ft)  Blackwell and Greene 2002.
Vibratory driving of 72-in (1.8 m) steel     10-1,500  180 dB rms at 10 m (33 ft)..  CALTRANS 2007.
 pipe pile.
Impact driving of 36-in (0.9 m) steel        10-1,500  195 dB rms at 10 m..........  WSDOT 2007.
 Pipe pile.
Impact driving of 66-in (1.7 m) CISS\1\     100-1,500  195 dB rms at 10 m..........  Reviewed in Hastings and
 piles.                                                                               Popper 2005.
----------------------------------------------------------------------------------------------------------------
\1\ CISS = cast-in-steel-shell.

    In-water construction activities associated with the project would 
include impact pile driving and vibratory pile driving. The sounds 
produced by these activities fall into one of two sound types: pulsed 
and non-pulsed (defined in next paragraph). Impact pile driving 
produces pulsed sounds, while vibratory pile driving produces non-
pulsed (or continuous) sounds. 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 sounds (e.g., explosions, gunshots, sonic booms, seismic 
pile driving pulses, and impact pile driving) are brief, broadband, 
atonal transients (ANSI 1986; Harris 1998) 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 decay period that may include a 
period of diminishing, oscillating maximal and minimal pressures. 
Pulsed sounds generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-pulse (intermittent or continuous sounds) can be tonal, 
broadband, or both. Some of these non-pulse sounds can be transient 
signals of short duration but without the essential properties of 
pulses (e.g., rapid rise time). Examples of non-pulse sounds include 
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.

Ambient Noise

    By definition, ambient noise is background noise, without a single 
source or point (Richardson et al. 1995). Ambient noise varies with 
location, season, time of day, and frequency. Ambient noise is 
continuous, but with much variability on time scales ranging from less 
than one second to one year (Richardson et al. 1995). Ambient 
underwater noise at the project area is widely variable over time due 
to a number of natural and anthropogenic sources. Sources of naturally 
occurring underwater noise include wind, waves, precipitation, and 
biological noise (e.g., shrimp, fish, cetaceans). There is also human-
generated noise from ship or boat traffic and other mechanical means 
(Urick 1983). Other sources of underwater noise at industrial 
waterfronts could come from cranes, generators, and other types of 
mechanized equipment on wharves or the adjacent shoreline.
    In the vicinity of the project area, the average broadband ambient 
underwater noise levels were measured at 114 dB re 1[micro]Pa between 
100 Hz and 20 kHz (Slater 2009). Peak spectral noise from industrial 
activity was noted below the 300 Hz frequency, with maximum levels of 
110 dB re 1[micro]Pa noted in the 125 Hz band. In the 300 Hz to 5 kHz 
range, average levels ranged between 83-99 dB re 1[micro]Pa. Wind-
driven wave noise dominated the background noise environment at 
approximately 5 kHz and above, and ambient noise levels flattened above 
10 kHz.
    Airborne noise levels at NBKB vary based on location but are 
estimated to average around 65 dBA (A-weighted decibels) in the 
residential and office park areas, with traffic noise ranging from 60-
80 dBA during daytime hours (Cavanaugh and Tocci 1998). The highest 
levels of airborne noise are produced along the waterfront and at the 
ordnance handling areas, where estimated noise levels range from 70-90 
dBA and may peak at 99 dBA for short durations. These higher noise 
levels are produced by a combination of sound sources including heavy 
trucks, forklifts, cranes, marine vessels, mechanized tools and 
equipment, and other sound-generating industrial or military 
activities.

Sound Thresholds

    Since 1997, NMFS has used generic sound exposure thresholds to 
determine when an activity in the ocean that produces sound might 
result in impacts to a marine mammal such that a take by harassment 
might occur (NMFS 2005b). To date, no studies have been conducted that 
examine impacts to marine mammals from pile driving sounds from which 
empirical noise thresholds have been established. Current NMFS practice 
regarding exposure of marine mammals to high level sounds is that 
cetaceans and pinnipeds exposed to impulsive sounds of 180 and 190 dB 
rms or above, respectively, are considered to have been taken by Level 
A (i.e., injurious) harassment. Behavioral harassment (Level B) is 
considered to have occurred when marine mammals are exposed to sounds 
at or above 160 dB rms for impulse sounds (e.g., impact pile driving) 
and 120 dB rms for continuous noise (e.g., vibratory pile driving), but 
below injurious thresholds. For airborne noise, 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.

Distance to Sound Thresholds

    Underwater Sound Propagation Formula--Pile driving would generate 
underwater noise that potentially could result in disturbance to marine 
mammals transiting the project area. Transmission loss (TL) underwater 
is the decrease in acoustic intensity as an acoustic pressure wave 
propagates out from a source. TL parameters vary with frequency, 
temperature, sea conditions, current, source and receiver depth, water 
depth, water chemistry, and bottom composition and topography. The 
formula for transmission loss is:

TL = B * log10(R) + C * R, where

B = logarithmic (predominantly spreading) loss
C = linear (scattering and absorption) loss
R = range from source in meters


[[Page 4304]]


For all underwater calculations in this assessment, linear loss (C) was 
not used (i.e., C = 0) and transmission loss was calculated using only 
logarithmic spreading. Therefore, using practical spreading (B = 15), 
the revised formula for transmission loss is TL = 15 log10 
(R).
    Underwater Noise 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. A large quantity of literature regarding sound pressure levels 
recorded from pile driving projects is available for consideration. In 
order to determine reasonable sound pressure levels and their 
associated affects on marine mammals that are likely to result from 
pile driving at NBKB, studies with similar properties to the proposed 
action were evaluated. Studies which met the following parameters were 
considered: (1) Pile materials--steel pipe piles (30-72 in [0.8-1.8 m] 
diameter); (2) Hammer machinery--vibratory and impact; and (3) Physical 
environment--shallow depth (less than 100 ft [30 m]). Table 2 details 
representative pile driving activities that have occurred in recent 
years. Due to the similarity of these actions and the Navy's proposed 
action, they represent reasonable sound pressure levels which could be 
anticipated.

        Table 2--Underwater Sound Pressure Levels From Similar In-Situ Monitored Construction Activities
----------------------------------------------------------------------------------------------------------------
                                                         Installation                           Measured sound
       Project & location          Pile size & type         method            Water depth       pressure levels
----------------------------------------------------------------------------------------------------------------
Mukilteo Test Piles, WA\1\......  36-in (0.9 m)       Impact............  7.3 m (24 ft).....  195 dB re 1
                                   steel pipe.                                                 [micro]Pa (rms)
                                                                                               at 10 m (33 ft).
Richmond-San Rafael Bridge, CA    66-in (1.7 m)       Impact............  4 m (13.1 ft).....  195 dB re 1
 \2\.                              steel CISS pile.                                            [micro]Pa (rms)
                                                                                               at 10 m.
Unknown Location, CA \2\........  72-in (1.8 m)       Vibratory.........  Approximately 5 m   180 dB re 1
                                   steel pipe pile.                        (16.4 ft).          [micro]Pa (rms)
                                                                                               at 10 m.
----------------------------------------------------------------------------------------------------------------
\1\ WSDOT 2007.
\2\ CALTRANS 2007.

    Several noise reduction measures can be employed during pile 
driving to reduce the high source pressures associated with impact pile 
driving. Among these is the use of bubble curtains, cofferdams, pile 
caps, or the use of vibratory installation. The efficacy of bubble 
curtains is dependent upon a variety of site-specific factors, 
including environmental conditions such as water current, sediment 
type, and bathymetry; the type and size of the pile; and the type and 
energy of the hammer. For the test pile program, the Navy intends to 
employ noise reduction techniques during impact pile driving, including 
the use of the Gunderboom Sound Attenuation System (SAS) or traditional 
bubble curtain sound attenuation system. Additionally, vibratory pile 
driving will be the primary installation method, which has lower source 
levels than impact pile driving. The calculations of the distances to 
the marine mammal noise thresholds described previously were calculated 
for impact installation with and without consideration for mitigation 
measures. Thorson and Reyff (2004) determined that a properly designed 
bubble curtain could provide a reduction of 5 to 20 dB. Based on 
information contained therein, distances calculated with consideration 
for mitigation assumed a 10 dB reduction in source levels from the use 
of sound attenuation devices, and the Navy used the mitigated distances 
for impact pile driving for all analysis in their application. 
Calculations for the marine mammal noise thresholds for vibratory 
installation were done based on in-situ recordings of vibratory 
installation and extraction data from CALTRANS (2007) which indicated a 
sound pressure level (SPL) of 180 db re 1[micro]Pa at 10 m (33 ft). 
This concurred with published literature from other studies which have 
in the past used a 15 dB reduction factor from source levels from 
impact driving recordings to calculate source levels for vibratory pile 
driving. Sound levels associated with vibratory pile removal are the 
same as those during vibratory installation (CALTRANS 2007) and have 
been taken into consideration in the modeling analysis. All calculated 
distances to and the total area encompassed by the marine mammal noise 
thresholds are provided in Tables 3 and 4, respectively. Calculated 
distance to thresholds using unmitigated impact driving is provided as 
reference; no unmitigated impact driving will occur. The USFWS has 
requested this as a measure to protect prey of the ESA-endangered 
marbled murrelet.

         Table 3--Calculated Distance(s) to Underwater Marine Mammal Noise Thresholds From Pile Driving
----------------------------------------------------------------------------------------------------------------
                                                               Distance in meters (ft) to threshold
                                                 ---------------------------------------------------------------
                   Description                                                                       Vibratory
                                                  Impact Level A  Impact Level A  Impact Level B   Level B (120
                                                   (190 dB \1\)    (180 dB \1\)    (160 dB \1\)       dB \1\)
----------------------------------------------------------------------------------------------------------------
Impact Driving, no mitigation...................         22 (72)       100 (328)   2,154 (7,067)             N/A
Impact Driving with bubble curtain (Mitigation =          5 (16)         22 (72)     464 (1,522)             N/A
 10 dB reduction in SPLs).......................
Vibratory pile driver...........................           2 (7)         10 (33)             N/A     \2\ 100,000
                                                                                                       (328,084)
----------------------------------------------------------------------------------------------------------------
All sound levels expressed in dB re 1 [micro]Pa rms.
Practical spreading loss (15 log, or 4.5 dB per doubling of distance) used for water depths 10-50 ft (3-15 m).
\1\ Sound pressure levels used for calculations were: 195 dB re 1 [micro]Pa @ 10 m (33 ft) for impact and 180 dB
  re 1 [micro]Pa @ 10 m for vibratory.
\2\ Range calculated is greater than what would be realistic. Hood Canal average width at site is 2.4 km (1.5
  mi), and is fetch limited from N to S at 20.3 km (12.6 mi).


[[Page 4305]]

    Calculated distances to thresholds, and calculated areas 
encompassed by thresholds, assume a field free of obstruction. This is 
unrealistic, however, because the Hood Canal does not represent open 
water conditions (free field) and therefore, sounds would attenuate as 
they encountered land masses or bends in the canal. As a result, some 
of the distances and areas of impact calculated cannot actually be 
attained within the project area. The actual distances to the 
behavioral disturbance thresholds for both impact and vibratory pile 
driving (464 m and 100,000 m [1,522 and 328,084 ft], respectively) may 
be shorter than those calculated due to the irregular contour of the 
waterfront, the narrowness of the canal, and the maximum fetch 
(furthest distance sound waves travel without obstruction [i.e., line 
of sight]) at the project area. Table 4 presents the calculated area 
encompassed for each threshold, as well as the actual area that is 
predicted to be encompassed due to obstructions as described above. 
Please see figures 6-1 and 6-2 in the Navy's application for graphical 
depictions of these areas for cetaceans and pinnipeds.

    Table 4--Area Encompassed (Per Pile) by the Underwater Marine Mammal Noise Thresholds From Pile Driving,
                                              Calculated and Actual
----------------------------------------------------------------------------------------------------------------
                                                  Area in square kilometers (mi\2\) encompassed by the threshold
                                                 ---------------------------------------------------------------
                   Description                                                                       Vibratory
                                                  Impact Level A  Impact Level A  Impact Level B   Level B (120
                                                   (190 dB \1\)    (180 dB \1\)    (160 dB \1\)       dB \1\)
----------------------------------------------------------------------------------------------------------------
Impact Driving with bubble curtain, calculated             0.000   0.002 (0.001)   0.676 (0.261)             N/A
 (Mitigation = 10 dB reduction in SPLs).........
Impact Driving with bubble curtain, actual                 0.000   0.002 (0.001)   0.509 (0.197)             N/A
 (Mitigation = 10 dB reduction in SPLs).........
Vibratory pile driver, calculated...............           0.000           0.000             N/A          31,416
                                                                                                        (12,130)
Vibratory pile driver, actual...................           0.000           0.000             N/A       41.5 (16)
----------------------------------------------------------------------------------------------------------------
\1\ Sound pressure levels used for calculations were: 195 dB re 1 [micro]Pa @ 10 m (33 ft) for impact and 180 dB
  re 1 [micro]Pa @ 10 m for vibratory.

    Airborne Sound Propagation Formula--Pile driving can generate 
airborne noise that could 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 sound pressure levels that could result in Level B 
behavioral harassment. The appropriate airborne noise threshold for 
behavioral disturbance for all pinnipeds, except harbor seals, is 100 
dB re 20 [micro]Pa rms (unweighted). For harbor seals the threshold is 
90 dB re 20 [micro]Pa rms (unweighted). A spherical spreading loss 
model, assuming average atmospheric conditions, was used to estimate 
the distance to the 100 dB and 90 dB re 20 [micro]Pa rms (unweighted) 
airborne thresholds. The formula for calculating spherical spreading 
loss is:

TL = 20log r
TL = Transmission loss
r = Distance from source to receiver

    *Spherical spreading results in a 6 dB decrease in sound pressure 
level per doubling of distance.
    Airborne Sound from Pile Driving--As was discussed for underwater 
noise 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. In order to 
determine reasonable airborne sound pressure levels and their 
associated effects on marine mammals that are likely to result from 
pile driving at NBKB, studies with similar properties to the proposed 
action, as described previously, were evaluated. Table 5 details 
representative pile driving activities that have occurred in recent 
years. Due to the similarity of these actions and the Navy's proposed 
action, they represent reasonable sound pressure levels which could be 
anticipated.

         Table 5--Airborne Sound Pressure Levels From Similar In-situ Monitored Construction Activities
----------------------------------------------------------------------------------------------------------------
                                                         Installation                           Measured sound
       Project & location          Pile size & type         method            Water depth       pressure levels
----------------------------------------------------------------------------------------------------------------
Northstar Island, AK \1\........  42-in (1.1 m)       Impact............  Approximately 12 m  97 dB re 20
                                   steel pipe pile..                       (40 ft).            [micro]Pa (rms)
                                                                                               at 525 ft (160
                                                                                               m).
Keystone Ferry Terminal, WA \2\.  30-in (0.8 m)       Vibratory.........  Approximately 9 m   98 dB re 20
                                   steel pipe pile.                        (30 ft).            [micro]Pa (rms)
                                                                                               at 36 ft (11 m).
----------------------------------------------------------------------------------------------------------------
\1\ Blackwell et al. 2004.
\2\ WSDOT 2010.

    Based on in-situ recordings from similar construction activities, 
the maximum airborne noise levels that would result from impact and 
vibratory pile driving are estimated to be 97 dB re 20 [micro]Pa (rms) 
at 525 ft (160 m) and 98 dB re 20 [micro]Pa (rms) at 36 ft (11 m), 
respectively (Blackwell et al. 2004; WSDOT 2010). The distances to the 
airborne thresholds were calculated with the airborne transmission loss 
formula presented previously. All calculated distances to and the total 
area encompassed by the airborne marine mammal noise thresholds are 
provided in Tables 6 and 7, respectively.

[[Page 4306]]



          Table 6--Calculated Distances to the Marine Mammal Noise Thresholds In-Air From Pile Driving
----------------------------------------------------------------------------------------------------------------
                                                                         Airborne behavioral disturbance
                                                               -------------------------------------------------
               Species                        Threshold          Distance to threshold    Distance to threshold
                                                                  impact pile driving     vibratory pile driving
----------------------------------------------------------------------------------------------------------------
Pinnipeds (except harbor seal).......  100 dB re 20 [micro]Pa   113 m (371 ft).........  9 m (30 ft).
                                        rms (unweighted).
Harbor seal..........................  90 dB re 20 [micro]Pa    358 m (1,175 ft).......  28 m (92 ft).
                                        rms (unweighted).
----------------------------------------------------------------------------------------------------------------


 Table 7--Calculated Area Encompassed (Per Pile) by the Marine Mammal Noise Thresholds In-Air From Pile Driving
----------------------------------------------------------------------------------------------------------------
                                                                         Airborne behavioral disturbance
                                                               -------------------------------------------------
               Species                        Threshold         Area encompassed by the  Area encompassed by the
                                                                  threshold for impact   threshold for vibratory
                                                                      pile driving             pile driving
----------------------------------------------------------------------------------------------------------------
Pinnipeds (except harbor seal).......  100 dB re 20 [micro]Pa   0.040 km\2\ (.015        0.000 km\2\.
                                        rms (unweighted).        mi\2\).
Harbor seal..........................  90 dB re 20 [micro]Pa    0.403 km\2\ (0.156       0.002 km\2\ (.001
                                        rms (unweighted).        mi\2\).                  mi\2\).
----------------------------------------------------------------------------------------------------------------

    The distance to the sea lion airborne threshold would be 113 m (371 
ft) for impact pile driving, and 9 m (30 ft) for vibratory pile 
driving. The distance to the harbor seal airborne threshold would be 
358 m (1,175 ft) for impact pile driving, and 28 m (92 ft) for 
vibratory pile driving. These distances are all less than the distances 
calculated for underwater sound thresholds. Since protective measures 
are in place out to the distances calculated for the underwater 
thresholds, the distances for the airborne thresholds will be covered 
fully by mitigation and monitoring measures in place for underwater 
sound thresholds. All construction noise associated with the project 
would not extend beyond the buffer zone for underwater sound that would 
be established to protect seals and sea lions. No haul-outs or 
rookeries are located within these radii. Please see figures 6-3 and 6-
4 of the Navy's application for graphical depictions of the distances 
and total area encompassed by each airborne sound threshold for 
pinnipeds that are predicted to occur at the project area due to pile 
driving.

Description of Marine Mammals in the Area of the Specified Activity

    There are six marine mammal species, three cetaceans and three 
pinnipeds, which may inhabit or transit through the waters nearby NBKB 
in the Hood Canal. These include the transient killer whale, harbor 
porpoise, Dall's porpoise, Steller sea lion, California sea lion, and 
the harbor seal. While the Southern Resident killer whale is resident 
to the inland waters of Washington and British Columbia, it has not 
been observed in the Hood Canal in decades, and therefore was excluded 
from further analysis. The Steller sea lion is the only marine mammal 
that occurs within the Hood Canal which is listed under the ESA; the 
Eastern DPS is listed as threatened. As noted previously, and in Table 
8, Steller sea lions are not present in the project area during the 
proposed project timeframe (July 16-October 31). Steller sea lions will 
not be discussed in detail. All marine mammal species are protected 
under the MMPA. This section summarizes the population status and 
abundance of these species, followed by detailed life history 
information. Table 8 lists the marine mammal species that occur in the 
vicinity of NBKB and their estimated densities within the project area 
during the proposed timeframe.

                    Table 8--Marine Mammals Present in the Hood Canal in the Vicinity of NBKB
----------------------------------------------------------------------------------------------------------------
                                                                                                     Density in
                                                                Relative                            warm season
             Species                Stock  abundance \1\   occurrence in Hood       Season of           \3\
                                                                  Canal            occurrence      (individuals/
                                                                                                       km\2\)
----------------------------------------------------------------------------------------------------------------
Steller sea lion; Eastern U.S.                 \2\ 50,464  Rare to occasional  Fall to late                 N/A
 DPS.                                                       use.                spring (Nov-mid
                                                                                April).
California sea lion; U.S. Stock.                  238,000  Common............  Fall to late           \4\ 0.410
                                                                                spring (Aug-May).
Harbor seal; WA inland waters          14,612 (CV = 0.15)  Common............  Year-round;             \5\ 1.31
 stock.                                                                         resident species
                                                                                in Hood Canal.
Killer whale; West Coast                              314  Rare to occasional  Year-round........     \6\ 0.038
 transient stock.                                           use.
Dall's porpoise; CA/OR/WA stock.       48,376 (CV = 0.24)  Rare to occasional  Year-round........     \7\ 0.043
                                                            use.
Harbor porpoise; WA inland             10,682 (CV = 0.38)  Rare to occasional  Year-round........     \7\ 0.011
 waters stock.                                              use.
----------------------------------------------------------------------------------------------------------------
\1\ NMFS marine mammal stock assessment reports at: https://www.nmfs.noaa.gov/pr/sars/species.htm.
\2\ Average of a given range.
\3\ Warm season refers to the period from May-Oct.
\4\ DoN 2010a.
\5\ Jeffries et al. 2003; Huber et al. 2001.
\6\ London 2006.
\7\ Agness and Tannenbaum 2009a.


[[Page 4307]]

California Sea Lion

    Species Description--California sea lions are members of the 
Otariid family (eared seals). The species, Zalophus californianus, 
includes three subspecies: Z. c. wollebaeki (in the Galapagos Islands), 
Z. c. japonicus (in Japan, but now thought to be extinct), and Z. c. 
californianus (found from southern Mexico to southwestern Canada; 
referred to here as the California sea lion) (Carretta et al. 2007). 
The California sea lion is sexually dimorphic. Males may reach 1,000 lb 
(454 kg) and 8 ft (2.4 m) in length; females grow to 300 lb (136 kg) 
and 6 ft (1.8 m) in length. Their color ranges from chocolate brown in 
males to a lighter, golden brown in females. At around five years of 
age, males develop a bony bump on top of the skull called a sagittal 
crest. The crest is visible in the dog-like profile of male sea lion 
heads, and hair around the crest gets lighter with age.
    Population Abundance--The U.S. stock of California sea lions may 
occur in the marine waters nearby NBKB. The stock is estimated at 
238,000 and the minimum population size of this stock is 141,842 
individuals (Carretta et al. 2007). These numbers are from counts 
during the 2001 breeding season of animals that were ashore at the four 
major rookeries in southern California and at haul-out sites north to 
the Oregon/California border. Sea lions that were at-sea or hauled-out 
at other locations were not counted (Carretta et al. 2007). An 
estimated 3,000 to 5,000 California sea lions migrate to waters of 
Washington and British Columbia during the non-breeding season from 
September to May (Jeffries et al. 2000). Peak numbers of up to 1,000 
California sea lions occur in Puget Sound (including Hood Canal) during 
this time period (Jeffries et al. 2000).
    Distribution--The geographic distribution of California sea lions 
includes a breeding range from Baja California, Mexico to southern 
California. During the summer, California sea lions breed on islands 
from the Gulf of California to the Channel Islands and seldom travel 
more than about 31 mi (50 km) from the islands (Bonnell et al. 1983). 
The primary rookeries are located on the California Channel Islands of 
San Miguel, San Nicolas, Santa Barbara, and San Clemente (Le Boeuf and 
Bonnell 1980; Bonnell and Dailey 1993). Their distribution shifts to 
the northwest in fall and to the southeast during winter and spring, 
probably in response to changes in prey availability (Bonnell and Ford 
1987).
    The non-breeding distribution extends from Baja California north to 
Alaska for males, and encompasses the waters of California and Baja 
California for females (Reeves et al. 2008; Maniscalco et al. 2004). In 
the non-breeding season, an estimated 3,000-5,000 adult and sub-adult 
males migrate northward along the coast to central and northern 
California, Oregon, Washington, and Vancouver Island from September to 
May (Jeffries et al. 2000) and return south the following spring (Mate 
1975; Bonnell et al. 1983). Along their migration, they are 
occasionally sighted hundreds of miles offshore (Jefferson et al. 
1993). Females and juveniles tend to stay closer to the rookeries 
(Bonnell et al 1983).
    Peak abundance in the Puget Sound is September to May. Although 
there are no regular California sea lion haul-outs within the Hood 
Canal (Jeffries et al. 2000), they often haul out at several opportune 
areas. They are known to utilize man-made structures such as piers, 
jetties, offshore buoys, and oil platforms (Riedman 1990). California 
sea lions in the Puget Sound sometimes haul out on log booms and Navy 
submarines, and are often seen rafted off river mouths (Jeffries et al. 
2000; DoN 2001). As many as forty California sea lions have been 
observed hauled out at NBKB on manmade structures (e.g., submarines, 
floating security fence, barges) (Agness and Tannenbaum 2009a; 
Tannenbaum et al. 2009a; Walters 2009). California sea lions have also 
been observed swimming in the Hood Canal in the vicinity of the project 
area on several occasions and likely forage in both nearshore marine 
and inland marine deeper waters (DoN 2001a).
    Behavior and Ecology--California sea lions feed on a wide variety 
of prey, including many species of fish and squid (Everitt et al. 1981; 
Roffe and Mate 1984; Antonelis et al. 1990; Lowry et al. 1991). In the 
Puget Sound region, they feed primarily on fish such as Pacific hake 
(Merluccius productus), walleye pollock (Theragra chalcogramma), 
Pacific herring (Clupea pallasii), and spiny dogfish (Squalus 
acanthias) (Calambokidis and Baird 1994). In some locations where 
salmon runs exist, California sea lions also feed on returning adult 
and out-migrating juvenile salmonids (London 2006). Sexual maturity 
occurs at around four to five years of age for California sea lions 
(Heath 2002). California sea lions are gregarious during the breeding 
season and social on land during other times.
    Acoustics--On land, California sea lions make incessant, raucous 
barking sounds; these have most of their energy at less than 2 kHz 
(Schusterman et al. 1967). Males vary both the number and rhythm of 
their barks depending on the social context; the barks appear to 
control the movements and other behavior patterns of nearby 
conspecifics (Schusterman 1977). Females produce barks, squeals, 
belches, and growls in the frequency range of 0.25-5 kHz, while pups 
make bleating sounds at 0.25-6 kHz. California sea lions produce two 
types of underwater sounds: clicks (or short-duration sound pulses) and 
barks (Schusterman et al. 1966, 1967; Schusterman and Baillet 1969). 
All underwater sounds have most of their energy below 4 kHz 
(Schusterman et al. 1967).
    The range of maximal hearing sensitivity underwater is between 1-28 
kHz (Schusterman et al. 1972). Functional underwater high frequency 
hearing limits are between 35-40 kHz, with peak sensitivities from 15-
30 kHz (Schusterman et al. 1972). The California sea lion shows 
relatively poor hearing at frequencies below 1 kHz (Kastak and 
Schusterman 1998). Peak hearing sensitivities in air are shifted to 
lower frequencies; the effective upper hearing limit is approximately 
36 kHz (Schusterman 1974). The best range of sound detection is from 2-
16 kHz (Schusterman 1974). Kastak and Schusterman (2002) determined 
that hearing sensitivity generally worsens with depth--hearing 
thresholds were lower in shallow water, except at the highest frequency 
tested (35 kHz), where this trend was reversed. Octave band noise 
levels of 65-70 dB above the animal's threshold produced an average 
temporary threshold shift (TTS; discussed later in ``Potential Effects 
of the Specified Activity on Marine Mammals'') of 4.9 dB in the 
California sea lion (Kastak et al. 1999).

Harbor Seal

    Species Description--Harbor seals, which are members of the Phocid 
family (true seals), inhabit coastal and estuarine waters and shoreline 
areas from Baja California, Mexico to western Alaska. For management 
purposes, differences in mean pupping date (i.e., birthing) (Temte 
1986), movement patterns (Jeffries 1985; Brown 1988), pollutant loads 
(Calambokidis et al. 1985) and fishery interactions have led to the 
recognition of three separate harbor seal stocks along the west coast 
of the continental U.S. (Boveng 1988). The three distinct stocks are: 
(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. 2007).

[[Page 4308]]

The inland waters of Washington stock is the only stock that is 
expected to occur within the project area.
    The average weight for adult seals is about 180 lb (82 kg) and 
males are slightly larger than females. Male harbor seals weigh up to 
245 lb (111 kg) and measure approximately 5 ft (1.5 m) in length. The 
basic color of harbor seals' coat is gray and mottled but highly 
variable, from dark with light color rings or spots to light with dark 
markings (NMFS 2008c).
    Population Abundance--Estimated population numbers for the inland 
waters of Washington, including the Hood Canal, Puget Sound, and the 
Strait of Juan de Fuca out to Cape Flattery, are 14,612 individuals 
(Carretta et al. 2007). The minimum population is 12,844 individuals. 
The harbor seal is the only species of marine mammal that is 
consistently abundant and considered resident in the Hood Canal 
(Jeffries et al. 2003). The population of harbor seals in Hood Canal is 
a closed population, meaning that they do not have much movement 
outside of Hood Canal (London 2006). The abundance of harbor seals in 
Hood canal has stabilized, and the population may have reached its 
carrying capacity in the mid-1990s with an approximate abundance of 
1,000 harbor seals (Jeffries et al. 2003).
    Distribution--Harbor seals are coastal species, rarely found more 
than 12 mi (20 km) from shore, and frequently occupy bays, estuaries, 
and inlets (Baird 2001). Individual seals have been observed several 
miles upstream in coastal rivers. Ideal harbor seal habitat includes 
haul-out sites, shelter during the breeding periods, and sufficient 
food (Bjorge 2002). Haul-out areas can include intertidal and subtidal 
rock outcrops, sandbars, sandy beaches, peat banks in salt marshes, and 
man-made structures such as log booms, docks, and recreational floats 
(Wilson 1978; Prescott 1982; Schneider and Payne 1983; Gilber and 
Guldager 1998; Jeffries et al. 2000). Human disturbance can affect 
haul-out choice (Harris et al. 2003).
    Harbor seals occur throughout Hood Canal and are seen relatively 
commonly in the area. They are year-round, non-migratory residents, and 
pup (i.e., give birth) in Hood Canal. Surveys in the Hood Canal from 
the mid-1970s to 2000 show a fairly stable population between 600-1,200 
seals (Jeffries et al. 2003). Harbor seals have been observed swimming 
in the waters along NBKB in every month of surveys conducted from 2007-
2010 (Agness and Tannenbaum 2009b; Tannenbaum et al. 2009b). On the 
NBKB waterfront, harbor seals have not been observed hauling out in the 
intertidal zone, but have been observed hauled-out on man-made 
structures such as the floating security fence, buoys, barges, marine 
vessels, and logs (Agness and Tannenbaum 2009a; Tannenbaum et al. 
2009a). The main haul-out locations for harbor seals in Hood Canal are 
located on river delta and tidal exposed areas at Quilcene, 
Dosewallips, Duckabush, Hamma Hamma, and Skokomish River mouths (see 
Figure 4-1 of the Navy's application), with the closest haul-out area 
to the project area being ten miles (16 km) southwest of NBKB at 
Dosewallips River mouth (London 2006).
    Behavior and Ecology--Harbor seals are typically seen in small 
groups resting on tidal reefs, boulders, mudflats, man-made structures, 
and sandbars. Harbor seals are opportunistic feeders that adjust their 
patterns to take advantage of locally and seasonally abundant prey 
(Payne and Selzer 1989; Baird 2001; Bj[oslash]rge 2002). The harbor 
seal diet consists of fish and invertebrates (Bigg 1981; Roffe and Mate 
1984; Orr et al. 2004). Although harbor seals in the Pacific Northwest 
are common in inshore and estuarine waters, they primarily feed at sea 
(Orr et al. 2004) during high tide. Researchers have found that they 
complete both shallow and deep dives during hunting depending on the 
availability of prey (Tollit et al. 1997). Their diet in Puget Sound 
consists of many of the prey resources that are present in the 
nearshore and deeper waters of NBKB, including hake, herring and adult 
and out-migrating juvenile salmonids. Harbor seals in Hood Canal are 
known to feed on returning adult salmon, including ESA-threatened 
summer-run chum (Oncorhynchus keta). Over a five-year study of harbor 
seal predation in the Hood Canal, the average percent escapement of 
summer-run chum consumed was eight percent (London 2006).
    Harbor seals mate at sea and females give birth during the spring 
and summer, although the pupping season varies by latitude. In coastal 
and inland regions of Washington, pups are born from April through 
January. Pups are generally born earlier in the coastal areas and later 
in the Puget Sound/Hood Canal region (Calambokidis and Jeffries 1991; 
Jeffries et al. 2000). Suckling harbor seal pups spend as much as forty 
percent of their time in the water (Bowen et al. 1999).
    Acoustics--In air, harbor seal males produce a variety of low-
frequency (less than 4 kHz) vocalizations, including snorts, grunts, 
and growls. Male harbor seals produce communication sounds in the 
frequency range of 100-1,000 Hz (Richardson et al. 1995). Pups make 
individually unique calls for mother recognition that contain multiple 
harmonics with main energy below 0.35 kHz (Bigg 1981; Thomson and 
Richardson 1995). Harbor seals hear nearly as well in air as underwater 
and had lower thresholds than California sea lions (Kastak and 
Schusterman 1998). Kastak and Schusterman (1998) reported airborne low 
frequency (100 Hz) sound detection thresholds at 65.4 dB re 20 [mu]Pa 
for harbor seals. In air, they hear frequencies from 0.25-30 kHz and 
are most sensitive from 6-16 kHz (Richardson 1995; Terhune and Turnbull 
1995; Wolski et al. 2003).
    Adult males also produce underwater sounds during the breeding 
season that typically range from 0.25-4 kHz (duration range: 0.1 s to 
multiple seconds; Hanggi and Schusterman 1994). Hanggi and Schusteman 
(1994) found that there is individual variation in the dominant 
frequency range of sounds between different males, and Van Parijs et 
al. (2003) reported oceanic, regional, population, and site-specific 
variation that could be vocal dialects. In water, they hear frequencies 
from 1-75 kHz (Southall et al. 2007) and can detect sound levels as 
weak as 60-85 dB re 1 [mu]Pa within that band. They are most sensitive 
at frequencies below 50 kHz; above 60 kHz sensitivity rapidly 
decreases.

Killer Whale

    Species Description--Killer whales are members of the Delphinid 
family and are the most widely distributed cetacean species in the 
world. Killer whales have a distinctive color pattern, with black 
dorsal and white ventral portions. They also have a conspicuous white 
patch above and behind the eye and a highly variable gray or white 
saddle area behind the dorsal fin. The species shows considerable 
sexual dimorphism. Adult males develop larger pectoral flippers, dorsal 
fins, tail flukes, and girths than females. Male adult killer whales 
can reach up to 32 ft (9.8 m) in length and weigh nearly 22,000 lb 
(10,000 kg); females reach 28 ft (8.5 m) in length and weigh up to 
16,500 lb (7,500 kg).
    Based on appearance, feeding habits, vocalizations, social 
structure, and distribution and movement patterns there are three types 
of populations of killer whales (Wiles 2004; NMFS 2005). The three 
distinct forms or types of killer whales recognized in the North 
Pacific Ocean are: (1) Resident, (2) Transient, and (3) Offshore. The 
resident and transient populations have

[[Page 4309]]

been divided further into different subpopulations based mainly on 
genetic analyses and distribution; not enough is known about the 
offshore whales to divide them into subpopulations (Wiles 2004). Only 
transient killer whales are known from the project area.
    Transient killer whales occur throughout the eastern North Pacific, 
and have primarily been studied in coastal waters. Their geographical 
range overlaps that of the resident and offshore killer whales. The 
dorsal fin of transient w