[Federal Register Volume 77, Number 83 (Monday, April 30, 2012)]
[Notices]
[Pages 25408-25435]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-10370]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XB146


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

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

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

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SUMMARY: NMFS has received an application from the U.S. Navy (Navy) for 
an Incidental Harassment Authorization (IHA) to take marine mammals, by 
harassment, incidental to construction activities as part of a pile 
replacement project. 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, six species of marine 
mammals during the specified activity.

DATES: Comments and information must be received no later than May 30, 
2012.

ADDRESSES: Comments on the application should be addressed to Tammy C. 
Adams, Acting Chief, Permits and Conservation Division, Office of 
Protected Resources, National Marine Fisheries Service, 1315 East-West 
Highway, Silver Spring, MD 20910-3225. The mailbox address for 
providing email comments is [email protected]. NMFS is not responsible 
for email comments sent to addresses other than the one provided here. 
Comments sent via email, 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 http://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.
    An electronic 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: http://www.nmfs.noaa.gov/pr/permits/incidental.htm. Documents cited in this

[[Page 25409]]

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) 427-8401.

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 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 March 8, 2012 from the Navy for the 
taking of marine mammals incidental to pile removal and removal in 
association with a pile replacement project in the Hood Canal at Naval 
Base Kitsap at Bangor, WA (NBKB). This pile replacement project is 
proposed to occur between July 16, 2012 and July 15, 2013. This IHA 
would cover the second and final year of this project; NMFS previously 
issued an IHA for the first year of work associated with this project 
(76 FR 30130; May 24, 2011). In-water work, including all pile removal 
activities, would occur only within an approved window from July 16-
February 15. Seven species of marine mammals are known from the waters 
surrounding NBKB: Steller sea lions (Eumetopias jubatus), California 
sea lions (Zalophus californianus), harbor seals (Phoca vitulina), 
killer whales (Orcinus orca; transient type only), Dall's porpoises 
(Phocoenoides dalli), harbor porpoises (Phocoena phocoena), and the 
humpback whale (Megaptera novaeangliae). These species may occur year-
round in the Hood Canal, with the exception of the Steller sea lion, 
which is present only from fall to late spring (October to mid-April), 
and the California sea lion, which is not present during part of summer 
(late June through July). 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 over 15 years 
and was therefore excluded from further analysis.
    NBKB provides berthing and support services for OHIO Class 
ballistic missile submarines (SSBN), also known as TRIDENT submarines. 
The Navy proposes to complete necessary repairs and maintenance at the 
Explosive Handling Wharf 1 (EHW-1) facility at NBKB as part of 
a pile replacement project to restore and maintain the structural 
integrity of the wharf and ensure its continued functionality to 
support necessary operational requirements. The EHW-1 facility, 
constructed in 1977, has become compromised due to the deterioration of 
the wharf's existing piling sub-structure. Under the proposed action, 
ninety-six 24-in (0.6-m) diameter concrete piles, twenty-one 12-in 
(0.3-m) diameter steel fender piles, eight 16-in (0.4-m) diameter steel 
falsework piles, and one 24-in diameter steel fender pile will be 
removed. The proposed action represents the remainder of work planned 
for the initial 2-year rehabilitation plan, following the work that was 
completed in 2011. The Navy may continue rehabilitation work at EHW-1 
in the long-term, but has no immediate plans to do so. All concrete 
piles would be removed via pneumatic chipping or similar method. All 
steel piles would be removed via vibratory hammer or direct pull; 
however, the analysis in this document assumes that all piles would be 
removed via vibratory hammer. No pile installation--and therefore no 
impact pile removal--is proposed for this action.
    For pile removal activities, the Navy used NMFS-promulgated 
thresholds for assessing 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 18- to 30-in (0.5- to 0.8-m) diameter steel 
pile removal events, or concrete pile removal events using similar 
methodology, 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 removal 
activities, and that as many as 1,416 Level B harassments may occur 
during the pile replacement project from generation of underwater 
sound. No incidents of harassment were predicted from airborne sounds 
associated with pile removal.

Description of the Specified Activity

    NBKB is located on the Hood Canal approximately 20 miles (32 km) 
west of Seattle, Washington (see Figures 2-1 through 2-3 in the Navy's 
application). NBKB provides berthing and support services for OHIO 
Class ballistic missile submarines (SSBN), also known as TRIDENT 
submarines. The Navy proposes a pile replacement project to maintain 
the structural integrity of EHW-1 and ensure its continued 
functionality to support operational requirements of the TRIDENT 
submarine program. The proposed actions with the potential to cause 
harassment of marine mammals within the waterways adjacent to NBKB, 
under the MMPA, are vibratory and pneumatic chipping pile removal 
operations associated with the pile replacement project. The proposed 
activities that would be authorized by this IHA would occur between 
July 16, 2012 and February 15, 2013. All in-water construction 
activities within the Hood

[[Page 25410]]

Canal are only permitted during July 16-February 15 in order to protect 
spawning fish populations.
    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 for 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 includes the removal of 126 steel and 
concrete piles at EHW-1. Please see Figures 1-1 through 1-3 of the 
Navy's application for conceptual and schematic representations of the 
work proposed for EHW-1. Of the piles requiring removal, 96 are 24-in 
(0.6-m) diameter hollow pre-cast concrete piles which will be excised 
down to the mud line. One additional 24-in steel fender pile, twenty-
one 12-in (0.3-m) steel fender piles, and eight 16-in (0.4-m) steel 
falsework piles will be extracted using a vibratory hammer or direct 
pull. Also included in the repair work is removal of the fragmentation 
barrier and walkway, construction of new cast-in-place pile caps 
(concrete formwork may be located below Mean Higher High Water [MHHW]), 
installation of the pre-stressed superstructure, installation of four 
sled-mounted cathodic protection (CP) systems, and installation or re-
installation of related appurtenances.
    During the first year of work, conducted under an IHA issued by 
NMFS (76 FR 30130; May 24, 2011), the Navy completed the following 
work:
     Removal of ten steel fender piles (eight 12-in diameter 
piles and two 24-in diameter piles) and associated fender system 
components. A fender pile, typically set beside slips or wharves, 
guides approaching vessels and is driven so as to yield slightly when 
struck in order to lessen the shock of contact. The fender system 
components attach the fender piles to the structure, and are above the 
water line.
     Installation of twenty-eight 30-in diameter steel piles 
and eight 16-in diameter steel falsework piles. These eight falsework 
piles would be removed in 2012.
    In addition, the Navy plans to complete construction of six cast-
in-place concrete pile caps in early 2012. Pile caps are situated on 
the tops of the steel piles located directly beneath the structure, and 
function as a load transfer mechanism between the superstructure and 
the piles. This work is above-water, and does not have the potential to 
impact marine mammals.
    During the 2012-13 in-water work season, the Navy proposes to 
complete the 2-year rehabilitation project, including the following 
work:
     Removal of 126 steel and concrete piles, as described 
previously.
     Removal of the concrete fragmentation barrier and walkway, 
used to get from the Wharf Apron to the Outboard Support. These 
structures will likely be removed by cutting the concrete into sections 
(potentially three or four in total) using a saw, or other equipment, 
and removed using a crane. The crane will lift the sections from the 
existing piles and place them on a barge.
     Installation of a pre-stressed concrete superstructure. 
The superstructure is the concrete deck of the wharf found above, or 
supported by, the caps or sills, including the deck, girders, and 
stringers.
     Installation of three sled-mounted passive CP systems. The 
passive CP system is a metallic rod or anode that is attached to a 
metal object to protect it from corrosion. The anode is composed of a 
more active metal than that on which it is mounted and is more easily 
oxidized, thus corroding first and acting as a barrier against 
corrosion for the object to which it is attached. This system would be 
banded to the steel piles to prevent metallic surfaces of the wharf 
from corroding due to the saline conditions in Hood Canal.
     Installation or re-installation of related appurtenances, 
the associated parts of the superstructure that connect the 
superstructure to the piles. These pieces include components such as 
bolts, welded metal hangers and fittings, brackets, etc.
    Concrete piles would be removed with a pneumatic chipping hammer or 
another tool capable of cutting through concrete. A pneumatic chipping 
hammer is similar to a jackhammer or other similar electric power tool, 
but uses compressed air instead of electricity, and consists of a steel 
piston that is reciprocated in a steel barrel. On its forward stroke 
the piston strikes the end of the chisel, reciprocating at a rate such 
that the chisel edge vibrates against the concrete with enough force to 
fragment or splinter the pile. When possible, piles will be first 
scored by a diver using a smaller pneumatic hammer, with the pile then 
moved slightly back and forth to break at the score. Remaining parts of 
the pile will be chipped away with the larger pneumatic hammer. If the 
scoring/breaking technique is not feasible, the entire base of the pile 
will be chipped away with a pneumatic hammer such that the pile may be 
removed. Concrete debris will be captured as practicable using debris 
curtains/sheeting and removed from the project area.
    The installation of the concrete pile caps, the concrete 
superstructure, and sled-mounted passive CP systems will occur out of 
the water and on the tops of the piles or attached to the wharf's 
superstructure. The removal of the fragmentation barrier and walkway 
will occur above the water with best management practices in place to 
prevent material from entering the water. While sound transmission from 
these activities could occur and enter the water, this is expected to 
be minimal, and above-water work is not considered to have the 
potential to impact marine mammals. However, these activities will 
occur during the in-water work window of July 16 to February 15 to 
minimize the potential for impacts to other listed species, 
particularly fish. The Navy will conduct acoustic monitoring for 
pneumatic chipping only--acoustic monitoring was conducted in 2011 for 
vibratory pile installation at NBKB--and will monitor the presence and 
behavior of marine mammals during vibratory pile removal and pneumatic 
chipping activities.
    The Navy estimates that steel pile removal will occur at an average 
rate of two piles per day, and is expected to require no more than 1 
hour per pile. It is estimated that concrete pile removal will occur at 
a rate of three piles per day, and is expected to take approximately 2 
hours per pile. This results in an estimated maximum of 2 hours per day 
of steel pile removal, and potentially 6 hours per day of pneumatic 
chipping. These two activities would likely not occur on the same day, 
however. On the basis of these estimates, the Navy states that steel 
pile removal would require 15 days and concrete pile removal would 
require an additional 32 days. The analysis contained herein is thus 
based upon these numbers, and assumes that (1) all marine mammals 
available to be incidentally taken within the relevant area would be; 
and (2) individual marine mammals may only be incidentally taken once 
in a 24-hour period--for purposes of authorizing specified numbers of 
take--regardless of actual number of exposures in that period.
    The number of construction barges (derrick and material) on site at 
any one time would vary depending on the type of construction taking 
place. Tug boats would tow barges to and from the construction site and 
position the barges for construction activity. Tug boats would leave 
the site once these tasks were completed and so would not be on site 
for extended periods. Smaller skiff-type boats would be on site 
performing various functions in support of

[[Page 25411]]

construction and monitoring requirements.

Description of Sound Sources

    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in 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 more rapidly in 
shallower water. Amplitude is the height of the sound pressure wave or 
the `loudness' of a sound and is typically measured using the decibel 
(dB) scale. A dB is the ratio between a measured pressure (with sound) 
and a reference pressure (sound at a constant pressure, established by 
scientific standards). It is a logarithmic unit that accounts for large 
variations in amplitude; therefore, relatively small changes in dB 
ratings correspond to large changes in sound pressure. When referring 
to SPLs (SPLs; the sound force per unit area), sound is referenced in 
the context of underwater sound pressure to 1 microPascal ([mu]Pa). One 
pascal is the pressure resulting from a force of one newton exerted 
over an area of one square meter. The source level 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, 1975). Rms accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper, 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. The 
compressions and decompressions associated with sound waves are 
detected as changes in pressure by aquatic life and man-made sound 
receptors such as hydrophones. Underwater sound levels (`ambient 
sound') are comprised of multiple sources, including 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). Even in the 
absence of anthropogenic sound, the sea is typically a loud 
environment. A number of sources of sound are likely to occur within 
Hood Canal, including the following (Richardson et al., 1995):
     Wind and waves: The complex interactions between wind and 
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of 
naturally occurring ambient noise for frequencies between 200 Hz and 50 
kHz (Mitson, 1995). In general, ambient noise levels tend to increase 
with increasing wind speed and wave height. Surf noise becomes 
important near shore, with measurements collected at a distance of 8.5 
km (5.3 mi) from shore showing an increase of 10 dB in the 100 to 700 
Hz band during heavy surf conditions.
     Precipitation noise: Noise from rain and hail impacting 
the water surface can become an important component of total noise at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times.
     Biological noise: Marine mammals can contribute 
significantly to ambient noise levels, as can some fish and shrimp. The 
frequency band for biological contributions is from approximately 12 Hz 
to over 100 kHz.
     Anthropogenic noise: Sources of ambient noise related to 
human activity include transportation (surface vessels and aircraft), 
dredging and construction, oil and gas drilling and production, seismic 
surveys, sonar, explosions, and ocean acoustic studies (Richardson et 
al., 1995). Shipping noise typically dominates the total ambient noise 
for frequencies between 20 and 300 Hz. In general, the frequencies of 
anthropogenic sounds are below 1 kHz and, if higher frequency sound 
levels are created, they will attenuate (decrease) rapidly (Richardson 
et al., 1995).
    In-water construction activities associated with the project would 
include vibratory pile removal and pneumatic chipping of concrete 
piles. The sounds produced by these activities are considered non-
pulsed (defined in next paragraph) as opposed to pulsed 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, and impact 
pile removal) 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 
those produced by vessels, aircraft, machinery operations such as 
drilling or dredging, vibratory pile removal, and active sonar systems. 
The duration of such sounds, as received at a distance, can be greatly 
extended in a highly reverberant environment.
    Vibratory hammers install or remove piles by vibrating them--thus 
causing liquefaction of the surrounding substrate--which then allows 
the piles to be more easily pushed or pulled. Vibratory hammers produce 
significantly less sound than impact hammers. Peak SPLs during 
vibratory installation may be 180 dB or greater, but are generally 10 
to 20 dB lower than SPLs generated during impact pile removal of the 
same-sized pile (Caltrans, 2009). Rise time is slower, reducing the 
probability and severity of injury (USFWS, 2009), and sound energy is 
distributed over a greater amount of time (Nedwell and Edwards, 2002; 
Carlson et al., 2001).

Ambient Sound

    The underwater acoustic environment consists of ambient sound, 
defined as environmental background sound levels lacking a single 
source or point (Richardson et al., 1995). The ambient underwater sound 
level of a region is defined by the total acoustical energy being 
generated by known and unknown sources, including sounds from both 
natural and anthropogenic sources. The sum of the various natural and 
anthropogenic sound sources at any given location and time depends not

[[Page 25412]]

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, the ambient sound levels at a given frequency and location can 
vary by 10-20 dB from day to day (Richardson et al., 1995).
    In the vicinity of the project area, the average broadband ambient 
underwater sound levels were measured at 114 dB re 1[micro]Pa between 
100 Hz and 20 kHz (Slater, 2009). Peak spectral sound 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 sound dominated the background sound environment at 
approximately 5 kHz and above, and ambient sound levels flattened above 
10 kHz.
    Airborne sound 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 sound ranging from 60-
80 dBA during daytime hours (Cavanaugh and Tocci, 1998). The highest 
levels of airborne sound are produced along the waterfront and at the 
ordnance handling areas, where estimated sound levels range from 70-90 
dBA and may peak at 99 dBA for short durations. These higher sound 
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 removal sounds from which 
empirical sound thresholds have been established. Current NMFS practice 
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. 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 would be produced by the proposed 
activities), 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.

Distance to Sound Thresholds

    Underwater Sound Propagation Formula--Pile removal would generate 
underwater noise that potentially could result in disturbance to marine 
mammals in the project area. Transmission loss (TL) is the decrease in 
acoustic intensity as an acoustic pressure wave propagates out from a 
source. TL parameters vary with frequency, temperature, sea conditions, 
current, source and receiver depth, water depth, water chemistry, and 
bottom composition and topography. A practical sound propagation 
modeling technique was used by the Navy to estimate the range from the 
activity to various SPL thresholds in water. This model follows a 
geometric propagation loss based on the distance from the pile, 
resulting in a 4.5 dB reduction in level for each doubling of distance 
from the source. In this model, the SPL at some distance away from the 
source (e.g., driven pile) is governed by a measured source level, 
minus the transmission loss of the energy as it dissipates with 
distance. The formula for underwater TL is:

TL = 15 * log10(R1/R2), where
    R1 = the distance of the modeled SPL from the pile, 
and
    R2 = the distance from the pile of the initial 
measurement.

    The degree to which underwater sound propagates away from a sound 
source is dependent on a variety of factors, most notably the water 
bathymetry and presence or absence of reflective or absorptive 
conditions including in-water structures and sediments. Spherical 
spreading occurs in a perfectly unobstructed (free-field) environment 
not limited by depth or water surface, resulting in a 6 dB reduction in 
sound level for each doubling of distance from the source 
(20*log[range]). Cylindrical spreading occurs in an environment in 
which sound propagation is bounded by the water surface and sea bottom, 
resulting in a reduction of 3 dB in sound level for each doubling of 
distance from the source (10*log[range]). The propagation environment 
along the NBKB waterfront conforms to neither spherical nor cylindrical 
spreading; as the receiver moves away from the shoreline, the water 
increases in depth, resulting in an expected propagation environment 
that would lie between spherical and cylindrical spreading loss 
conditions. Since there is no available data regarding propagation loss 
along the NBKB waterfront, a practical spreading loss model was adopted 
as the most likely approximation of the sound propagation environment. 
Hydroacoustic monitoring results from the Navy's Test Pile Project (see 
76 FR 38361; July 30, 2011) and from the first year of EHW-1 
construction will be used, when available, to confirm the validity of 
the practical spreading model for estimating acoustic propagation in 
the project area.
    Underwater Sound from Pile Removal--The intensity of pile removal 
sounds is greatly influenced by factors such as the type of piles, 
hammers, and the physical environment in which the activity takes 
place. Despite a large quantity of literature regarding SPLs recorded 
from pile removal projects, there is a general lack of empirical data 
regarding vibratory pile removal and the acoustic output of chipping 
hammers. In order to determine reasonable SPLs and their associated 
affects on marine mammals that are likely to result from pile removal 
at NBKB, studies with similar properties to the proposed action were 
evaluated. Overall, studies which met the following parameters were 
considered: (1) Pile size and materials: Steel pipe pile removal (12- 
to 24-in diameter) and concrete pile removal with chipping hammer or 
similar method (because these tools are used to chip portions of 
concrete from the pile, sound output is not tied to pile size); (2) 
Hammer machinery: Vibratory hammer for steel piles and pneumatic 
chipping hammer or similar tool for concrete piles; and (3) Physical 
environment: Shallow depth (less than 100 ft [30 m]). Table 1 details 
representative SPLs that have been recorded from similar construction 
activities in recent years. Due to the similarity of these actions and 
the Navy's proposed action, these values represent reasonable SPLs 
which could be anticipated, and which were used in the acoustic 
modeling and analysis.

[[Page 25413]]



                            Table 1--Representative Underwater SPLs for Pile Removal
----------------------------------------------------------------------------------------------------------------
      Project and  location       Pile size and type    Removal method        Water depth        Measured SPLs
----------------------------------------------------------------------------------------------------------------
California (location not          24-in steel pipe    Vibratory hammer..  ~15 m (49 ft).....  165 dB re: 1
 specified).                       pile.                                                       [mu]Pa (rms) at
                                                                                               10 m (33 ft)
United Kingdom (location not      Concrete (size not  Jackhammer........  Unknown...........  161 dB re: 1
 specified).                       specified).                                                 [mu]Pa (rms) at 1
                                                                                               m (3.3 ft)
----------------------------------------------------------------------------------------------------------------
Sources: Caltrans, 2007; Nedwell and Howell, 2004.

    Based on these representative SPLs, the source levels used in this 
analysis are 180 dB re: 1 [mu]Pa (rms) for vibratory removal and 161 dB 
re: 1 [mu]Pa (rms) for pneumatic chipping, which is considered 
analogous to the jackhammer. Therefore, vibratory removal would produce 
SPLs that are below the injury threshold for pinnipeds, while SPLs 
resulting from pneumatic chipping are well below levels that may cause 
injury to any marine mammal. All calculated distances to and the total 
area encompassed by the marine mammal underwater sound thresholds are 
provided in Table 2.

      Table 2--Calculated Distance(s) to and Area Encompassed by Underwater Marine Mammal Sound Thresholds
----------------------------------------------------------------------------------------------------------------
                Threshold                                  Distance                      Area, km\2\ (mi\2\)
----------------------------------------------------------------------------------------------------------------
Vibratory removal, cetacean injury (180    1 m (3.3 ft)                             0.000003 (0.000001)
 dB).
Vibratory removal, disturbance (120 dB)..  10,000 m (32,808 ft)                     314 (121)
Pneumatic chipping, disturbance (120 dB).  542 m (1,778 ft)                         0.9 (0.4)
----------------------------------------------------------------------------------------------------------------

    The values presented in Tables 2 assume a field free of 
obstruction, which is unrealistic, because Hood Canal does not 
represent open water conditions (free field). Therefore, sounds would 
attenuate as they encounter land masses or bends in the canal. As a 
result, some of the distances and areas of impact calculated cannot 
actually be attained at the project area. The actual distances to the 
behavioral disturbance thresholds for vibratory pile removal and 
pneumatic chipping 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. The actual 
areas encompassed by sound exceeding or reaching the 120 dB threshold 
are 35.9 km\2\ and 0.6 km\2\ for vibratory removal and pneumatic 
chipping, respectively. See Figures 6-1 and 6-2 of the Navy's 
application for a depiction of the size of areas in which each 
underwater sound threshold is predicted to occur at the project area 
due to pile removal.
    Airborne Sound Propagation Formula--Pile removal can generate 
airborne sound 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 SPLs that could result in Level B behavioral harassment. 
The appropriate airborne sound threshold for behavioral disturbance for 
all pinnipeds, except harbor seals, is 100 dB re: 20 [mu]Pa rms 
(unweighted). For harbor seals, the threshold is 90 dB re: 20 [mu]Pa 
rms (unweighted). A spherical spreading loss model, assuming average 
atmospheric conditions, was used to estimate the distance to the 
airborne thresholds. The formula for calculating spherical spreading 
loss is:

TL = 20log(R1/R2)
TL = Transmission loss
R1 = the distance of the modeled SPL from the pile, and
R2 = the distance from the pile of the initial 
measurement.

    Airborne Sound from Pile Installation--As was discussed for 
underwater sound from pile removal, the intensity of pile removal 
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 SPLs and their 
associated effects on marine mammals that are likely to result from 
pile removal at NBKB, studies with similar properties to the proposed 
action, as described previously, were evaluated. Table 3 details 
representative pile removal activities that have occurred in recent 
years. Due to the similarity of these actions and the Navy's proposed 
action, they represent reasonable SPLs which could be anticipated. 
Given these data, representative source levels are approximately 116.5 
dB re: 20 [mu]Pa rms (unweighted) for vibratory removal and 112 dB re: 
20 [mu]Pa rms (unweighted) for chipping.

                                      Table 3--Representative Airborne SPLs
----------------------------------------------------------------------------------------------------------------
      Project and  location       Pile size and type        Method            Water depth        Measured SPLs
----------------------------------------------------------------------------------------------------------------
Wahkiakum Ferry Terminal, WA....  18-in (0.5 m)       Vibratory.........  ~ 3-4 m (10-12 ft)  87.5 dB re: 20
                                   steel pipe pile.                                            [mu]Pa (rms) at
                                                                                               50 ft (15.2 m)
Keystone Ferry Terminal, WA.....  30-in (0.8 m)       Vibratory.........  ~ 9 m (30 ft).....  98 dB re: 20
                                   steel pipe pile.                                            [mu]Pa (rms) at
                                                                                               36 ft (10.9 m)

[[Page 25414]]

 
Not specified...................  Concrete, size not  Chipping hammer...  Unknown...........  92 dB re: 20
                                   specified.                                                  [mu]Pa (rms) at
                                                                                               10 m (33 ft)
----------------------------------------------------------------------------------------------------------------
Sources: WSDOT, 2010; Cheremisinoff, 1996.

    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 marine mammal 
underwater sound thresholds are provided in Table 4.

       Table 4--Calculated Distance(s) to and Area Encompassed by Airborne Marine Mammal Sound Thresholds
----------------------------------------------------------------------------------------------------------------
               Threshold                              Distance                       Area, km\2\ (mi\2\)
----------------------------------------------------------------------------------------------------------------
Vibratory removal, pinniped             7 m (23 ft)                          0.0002 (0.0001)
 disturbance (100 dB).
Vibratory removal, harbor seal          20 m (66 ft)                         0.001 (0.0005)
 disturbance (90 dB).
Pneumatic chipping, pinniped            4 m (13 ft)                          0.00005 (0.00002)
 disturbance (100 dB).
Pneumatic chipping, harbor seal         13 m (43 ft)                         0.0005 (0.0002)
 disturbance (90 dB).
----------------------------------------------------------------------------------------------------------------

    All airborne distances are less than those calculated for 
underwater sound thresholds for disturbance. 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. Construction sound associated with the 
project would not extend beyond the disturbance zone for underwater 
sound that would be established to protect pinnipeds. No haul-outs or 
rookeries are located within the airborne harassment radii. See Figures 
6-3 through 6-6 of the Navy's application for a depiction of the size 
of areas in which each airborne sound threshold is predicted to occur 
at the project area due to pile removal.

Description of Marine Mammals in the Area of the Specified Activity

    There are seven marine mammal species, four 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, 
harbor seal, and humpback whale. 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 over 15 years, 
and therefore was excluded from further analysis. The Steller sea lion 
and humpback whale are the only marine mammals that may occur within 
the Hood Canal that are listed under the ESA; the humpback whale is 
listed as endangered and the eastern distinct population segment (DPS) 
of Steller sea lion is listed as threatened. 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 5 lists the marine mammal species that occur 
in the vicinity of NBKB and their estimated densities within the 
project area during the proposed timeframe. Daily maximum abundance 
data only is presented for sea lions because sightings data have no 
defined survey area.

                          Table 5--Marine Mammals That May Be Present in the Hood Canal
----------------------------------------------------------------------------------------------------------------
                                                                                                  Density during
                                                                  Relative                         in-water work
            Species                  Stock abundance \1\        occurrence in       Season of         season
                                                               Hood Canal \2\      occurrence      (individuals/
                                                                                                      km\2\)
----------------------------------------------------------------------------------------------------------------
Steller sea lion--Eastern U.S.  58,334-72,223 \3\...........  Common..........  Fall to late             \4\ 1.2
 DPS.                                                                            spring (Oct to
                                                                                 mid-April).
California sea lion--U.S.       238,000.....................  Common..........  Fall to late            \4\ 26.2
 stock.                                                                          spring (Aug to
                                                                                 early June).
Harbor seal--WA inland waters   14,612 (CV = 0.15)..........  Common..........  Year-round;             \5\ 1.31
 stock.                                                                          resident
                                                                                 species in Hood
                                                                                 Canal.
Humpback whale--CA/OR/WA stock  2,043 (CV = 0.10)...........  Extremely rare..  Year-round in          \6\ 0.003
                                                                                 Puget Sound.
Killer whale--West Coast        354.........................  Rare............  Year-round......       \7\ 0.038
 transient stock.
Dall's porpoise--CA/OR/WA       42,000 (CV = 0.33)..........  Rare............  Year-round......       \7\ 0.014
 stock.
Harbor porpoise--WA inland      10,682 (CV = 0.38)..........  Possible common   Year-round......       \9\ 0.250
 waters stock.                                                 to occasional
                                                               presence.
----------------------------------------------------------------------------------------------------------------
\1\ NMFS marine mammal stock assessment reports at: http://www.nmfs.noaa.gov/pr/sars/species.htm.
\2\ Common: Consistently present either year-round or during non-breeding season; Occasional: Documented at
  irregular intervals; Rare: Sporadic sightings not occurring on a yearly basis; Extremely rare: Generally not
  observed over multiple years.
\3\ Range calculated on basis of total pup counts 2006-2009 and extrapolation factors derived from vital rate
  parameters estimated for an increasing population.

[[Page 25415]]

 
\4\ Density for sea lions is not calculated due to the lack of a defined survey area for sightings data.
  Abundance calculated as the average of the maximum number of individuals present during shore-based surveys at
  NBKB waterfront during the in-water construction season.
\5\ Jeffries et al., 2003; Huber et al., 2001.
\6\ Density calculated on the basis of one individual observed in Hood Canal.
\7\ Density calculated as the maximum number of individuals present at a given time during occurrences of killer
  whales at Hood Canal in 2003 and 2005 (London, 2006) divided by the area of Hood Canal.
\8\ Density calculated from number of individuals observed in 18 vessel-based surveys of NBKB waterfront area
  (Tannenbaum et al., 2009, 2011).
\9\ Density calculated from number of individuals observed during vessel-based surveys conducted during Test
  Pile Program and corrected for detectability (Navy, in prep.).

Steller Sea Lion

    Species Description--Steller sea lions are the largest members of 
the Otariid (eared seal) family. Steller sea lions show marked sexual 
dimorphism, in which adult males are noticeably larger and have 
distinct coloration patterns from females. Males average approximately 
1,500 lb (680 kg) and 10 ft (3 m) in length; females average about 700 
lb (318 kg) and 8 ft (2.4 m) in length. Adult females have a tawny to 
silver-colored pelt. Males are characterized by dark, dense fur around 
their necks, giving a mane-like appearance, and light tawny coloring 
over the rest of their body (NMFS, 2008a). Steller sea lions are 
distributed mainly around the coasts to the outer continental shelf 
along the North Pacific Ocean 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. The population 
is divided into the Western and the Eastern Distinct Population 
Segments (DPSs) at 144[deg] W (Cape Suckling, Alaska). The Western DPS 
includes Steller sea lions that reside in the central and western Gulf 
of Alaska, Aleutian Islands, as well as those that inhabit coastal 
waters and breed in Asia (e.g., Japan and Russia). The Eastern DPS 
extends from California to Alaska, including the Gulf of Alaska.
    Status--Steller sea lions were listed as threatened range-wide 
under the ESA in 1990. After division into two DPSs, the western DPS 
was listed as endangered under the ESA in 1997, while the eastern DPS 
remained classified as threatened. Animals found in the Region of 
Activity are from the eastern DPS (NMFS, 1997a; Loughlin, 2002; Angliss 
and Outlaw, 2005). The eastern DPS breeds in rookeries located in 
southeast Alaska, British Columbia, Oregon, and California. While some 
pupping has been reported recently along the coast of Washington, there 
are no active rookeries in Washington. A final revised species recovery 
plan addresses both DPSs (NMFS, 2008a).
    NMFS designated critical habitat for Steller sea lions in 1993. 
Critical habitat is associated with breeding and haul-out sites in 
Alaska, California, and Oregon, and includes so-called `aquatic zones' 
that extend 3,000 ft (900 m) seaward in state and federally managed 
waters from the baseline or basepoint of each major rookery in Oregon 
and California (NMFS, 2008a). Three major rookery sites in Oregon 
(Rogue Reef, Pyramid Rock, and Long Brown Rock and Seal Rock on Orford 
Reef at Cape Blanco) and three rookery sites in California (Ano Nuevo 
I, Southeast Farallon I, and Sugarloaf Island and Cape Mendocino) are 
designated critical habitat (NMFS, 1993). There is no designated 
critical habitat within the Region of Activity.
    Factors that have previously been identified as threats to Steller 
sea lions include reduced food availability, possibly resulting from 
competition with commercial fisheries; incidental take and intentional 
kills during commercial fish harvests; subsistence take; entanglement 
in marine debris; disease; pollution; and harassment. Steller sea lions 
are also sensitive to disturbance at rookeries (during pupping and 
breeding) and haul-out sites.
    The Recovery Plan for the Steller Sea Lion (NMFS, 2008a) states 
that the overall abundance of Steller sea lions in the eastern DPS has 
increased for a sustained period of at least three decades, and that 
pup production has increased significantly, especially since the mid-
1990s. Between 1977 and 2002, researchers estimated that overall 
abundance of the eastern DPS had increased at an average rate of 3.1 
percent per year (NMFS, 2008a; Pitcher et al., 2007). NMFS' most recent 
stock assessment report estimates that population for the eastern DPS 
is a minimum of 52,847 individuals; this estimate is not corrected for 
animals at sea, and actual population is estimated to be within the 
range 58,334 to 72,223 (Allen and Angliss, 2010). The minimum count for 
Steller sea lions in Oregon and Washington was 5,813 in 2002 (Pitcher 
et al., 2007; Allen and Angliss, 2010).
    The abundance of the eastern DPS of Steller sea lions is increasing 
throughout the northern portion of its range (southeast Alaska and 
British Columbia), and stable or increasing in the central portion 
(Oregon through central California). Surveys indicate that pup 
production in Oregon increased at 3 percent per year from 1990-2009, 
while pup production in California increased at 5 percent per year 
between 1996 and 2009, with the number of non-pups reported as stable. 
The best available information indicates that, overall, the eastern DPS 
has increased from an estimated 18,040 animals in 1979 to an estimated 
63,488 animals in 2009; therefore the overall estimated rate of 
increase for this period is 4.3 percent per year (NMML, 2012).
    In the far southern end of Steller sea lion range (Channel Islands 
in southern California), population declined significantly after the 
1930s--probably due to hunting and harassment (Bartholomew and 
Boolootian, 1960; Bartholomew, 1967)--and several rookeries and haul-
outs have been abandoned. The lack of recolonization at the 
southernmost portion of the range (e.g., San Miguel Island rookery), 
despite stability in the non-pup portion of the overall California 
population, is likely a response to a suite of factors, including 
changes in ocean conditions (e.g., warmer temperatures) that may be 
contributing to habitat changes that favor California sea lions over 
Steller sea lions (NMFS, 2007) and competition for space on land, and 
possibly prey, with species that have experienced explosive growth over 
the past three decades (California sea lions and northern elephant 
seals [Mirounga angustirostris]). Although recovery in California has 
lagged behind the rest of the DPS, this portion of the DPS' range has 
recently shown a positive growth rate (NMML, 2012). While non-pup 
counts in California in the 2000s are only 34 percent of pre-decline 
counts (1927-47), the population has increased significantly since 
1990.
    Despite the abandonment of certain rookeries in California, pup 
production at other rookeries in California has increased over the last 
20 years and, overall, the eastern DPS has increased at an average 
annual growth rate of 4.3 percent per year for 30 years. Even though 
these rookeries might not be recolonized, their loss has not prevented 
the increasing abundance of Steller sea lions in California or in the 
eastern DPS overall.

[[Page 25416]]

    Because the eastern DPS of Steller sea lion is currently listed as 
threatened under the ESA, it is therefore designated as depleted and 
classified as a strategic stock under the MMPA. However, the eastern 
DPS has been considered a potential candidate for removal from listing 
under the ESA by the Steller sea lion recovery team and NMFS (NMFS, 
2008), based on observed annual rates of increase. Although the stock 
size has increased, the status of this stock relative to its Optimum 
Sustainable Population (OSP) size is unknown. The overall annual rate 
of increase of the eastern stock has been consistent and long-term, and 
may indicate that this stock is reaching OSP.
    Behavior and Ecology--Steller sea lions forage near shore and in 
pelagic waters. They are capable of traveling long distances in a 
season and can dive to approximately 1,300 ft (400 m) in depth. They 
also use terrestrial habitat as haul-out sites for periods of rest, 
molting, and as rookeries for mating and pupping during the breeding 
season. At sea, they are often seen alone or in small groups, but may 
gather in large rafts at the surface near rookeries and haul-outs. 
Steller sea lions prefer the colder temperate to sub-arctic waters of 
the North Pacific Ocean. Haul-outs and rookeries usually consist of 
beaches (gravel, rocky or sand), ledges, and rocky reefs. In the Bering 
and Okhotsk Seas, sea lions may also haul-out on sea ice, but this is 
considered atypical behavior (NOAA, 2010a).
    Steller sea lions are gregarious animals that often travel or haul 
out in large groups of up to 45 individuals (Keple, 2002). At sea, 
groups usually consist of female and subadult males; adult males are 
usually solitary while at sea (Loughlin, 2002). In the Pacific 
Northwest, breeding rookeries are located in British Columbia, Oregon, 
and northern California. Steller sea lions form large rookeries during 
late spring when adult males arrive and establish territories (Pitcher 
and Calkins, 1981). Large males aggressively defend territories while 
non-breeding males remain at peripheral sites or haul-outs. Females 
arrive soon after and give birth. Most births occur from mid-May 
through mid-July, and breeding takes place shortly thereafter. Most 
pups are weaned within a year. Non-breeding individuals may not return 
to rookeries during the breeding season but remain at other coastal 
haul-outs (Scordino, 2006).
    Steller sea lions are opportunistic predators, feeding primarily on 
fish and cephalopods, and their diet varies geographically and 
seasonally (Bigg, 1985; Merrick et al., 1997; Bredesen et al., 2006; 
Guenette et al., 2006). Foraging habitat is primarily shallow, 
nearshore and continental shelf waters; freshwater rivers; and also 
deep waters (Reeves et al., 2008; Scordino, 2010). Steller sea lions 
occupy major winter haul-out sites on the coast of Vancouver Island in 
the Strait of Juan de Fuca and the Georgia Basin (Bigg, 1985; Olesiuk, 
2008); the closest breeding rookery to the project area is at Carmanah 
Point near the western entrance to the Strait of Juan de Fuca. There 
are no known breeding rookeries in Washington (NMFS, 1992; Angliss and 
Outlaw, 2005) but Eastern stock Steller sea lions are present year-
round along the outer coast of Washington at four major haul-out sites 
(NMFS, 2008a). Both sexes are present in Washington waters; these 
animals are likely immature or non-breeding adults from rookeries in 
other areas (NMFS, 2008a). In Washington, Steller sea lions primarily 
occur at haul-out sites along the outer coast from the Columbia River 
to Cape Flattery. In inland waters, Steller sea lions use haul-out 
sites along the Vancouver Island coastline of the Strait of Juan de 
Fuca (Jeffries et al., 2000; COSEWIC, 2003; Olesiuk, 2008). Numbers 
vary seasonally in Washington waters with peak numbers present during 
the fall and winter months (Jeffries et al., 2000). The highest 
breeding season Steller sea lion count at Washington haul-out sites was 
847 individuals during the period from 1978 to 2001 (Pitcher et al., 
2007). Non-breeding season surveys of Washington haul-out sites 
reported as many as 1,458 individuals between 1980 and 2001 (NMFS, 
2008a).
    Steller sea lions are occasionally present at the Toliva Shoals 
haul-out site in south Puget Sound (Jeffries et al., 2000) and a rock 
three miles south of Marrowstone Island (NMFS, 2010). Fifteen Steller 
sea lions have been observed using this haul-out site. At NBKB, Steller 
sea lions have been observed hauled out on submarines at Delta Pier on 
several occasions from 2008 through 2011 during fall through spring 
months (October to April) (Navy 2010). Other potential haul-out sites 
may include isolated islands, rocky shorelines, jetties, buoys, rafts, 
and floats (Jeffries et al., 2000). Steller sea lions likely utilize 
foraging habitats in Hood Canal similar to those of the California sea 
lion and harbor seal, which include marine nearshore and deeper water 
habitats.
    Acoustics--Like all pinnipeds, the Steller sea lion is amphibious; 
while all foraging activity takes place in the water, breeding behavior 
is carried out on land in coastal rookeries (Mulsow and Reichmuth 
2008). On land, territorial male Steller sea lions regularly use loud, 
relatively low-frequency calls/roars to establish breeding territories 
(Schusterman et al., 1970; Loughlin et al., 1987). The calls of females 
range from 0.03 to 3 kHz, with peak frequencies from 0.15 to 1 kHz; 
typical duration is 1.0 to 1.5 sec (Campbell et al., 2002). Pups also 
produce bleating sounds. Individually distinct vocalizations exchanged 
between mothers and pups are thought to be the main modality by which 
reunion occurs when mothers return to crowded rookeries following 
foraging at sea (Mulsow and Reichmuth, 2008).
    Mulsow and Reichmuth (2008) measured the unmasked airborne hearing 
sensitivity of one male Steller sea lion. The range of best hearing 
sensitivity was between 5 and 14 kHz. Maximum sensitivity was found at 
10 kHz, where the subject had a mean threshold of 7 dB. The underwater 
hearing threshold of a male Steller sea lion was significantly 
different from that of a female. The peak sensitivity range for the 
male was from 1 to 16 kHz, with maximum sensitivity (77 dB re: 1[mu]Pa-
m) at 1 kHz. The range of best hearing for the female was from 16 to 
above 25 kHz, with maximum sensitivity (73 dB re: 1[mu]Pa-m) at 25 kHz. 
However, because of the small number of animals tested, the findings 
could not be attributed to either individual differences in sensitivity 
or sexual dimorphism (Kastelein et al., 2005).

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.
    Status--The U.S. stock of California sea lions 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

[[Page 25417]]

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). The stock 
has likely reached its carrying capacity and, even though current total 
human-caused mortality is unknown (due to a lack of observer coverage 
in the California set gillnet fishery that historically has been the 
largest source of human-caused mortalities), California sea lions are 
not considered a strategic stock under the MMPA because total human-
caused mortality is still likely to be less than the potential 
biological removal (PBR). 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).
    California sea lions are present in Hood Canal during much of the 
year with the exception of mid-June through August, and occur regularly 
in the vicinity of the project site, as observed during Navy waterfront 
surveys conducted at NBKB from April 2008 through June 2010 (Navy, 
2010). They are known to utilize man-made structures such as piers, 
jetties, offshore buoys, log booms, and oil platforms (Riedman, 1990), 
and are often seen rafted off of river mouths (Jeffries et al., 2000). 
Although there are no regular California sea lion haul-outs known 
within the Hood Canal (Jeffries et al., 2000), they are frequently 
observed hauled out at several opportune areas at NBKB (e.g., 
submarines, floating security fence, barges). As many as 58 California 
sea lions have been observed hauled out together at NBKB (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 sound 
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). 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).
    Status--Estimated population numbers for the inland waters of 
Washington, including the Hood Canal,

[[Page 25418]]

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).
    Harbor seals are not considered to be depleted under the MMPA or 
listed under the ESA. Human-caused mortality relative to PBR is 
unknown, but it is considered to be small relative to the stock size. 
Therefore, the Washington Inland Waters stock of harbor seals is not 
classified as a strategic stock.
    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 Tannebaum, 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, outside the potential area of effect for this 
project (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 5-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.

Humpback Whale

    Species Description--The humpback whale is a baleen whale, and a 
member of the Balaenopterid family (rorquals), with a worldwide 
distribution in all ocean basins. Similar to all baleen whales, adult 
females are larger than adult males, reaching lengths of up to 60 ft 
(18 m). Their body coloration is primarily dark grey, but individuals 
have a variable amount of white on their pectoral fins and belly. This 
variation is so distinctive that the pigmentation pattern on the 
undersides of their flukes is used to identify individual whales. 
Humpback whales are known for their long pectoral fins, which can be up 
to 15 ft (4.6 m) in length and provide significant maneuverability. In 
the summer, most humpback whales are found in high latitude or highly 
biologically productive feeding grounds. In the winter, they congregate 
in subtropical or tropical waters for mating.
    In the North Pacific, there are at least three separate 
populations: (1) CA/OR/WA stock, which winters in coastal Central 
America and Mexico and migrates to areas ranging from the coast of 
California to southern British Columbia in summer/fall; (2) Central 
North Pacific stock, which winters in the Hawaiian Islands and migrates 
to northern British Columbia/Southeast Alaska and Prince William Sound 
west to Kodiak; and (3) Western North Pacific

[[Page 25419]]

stock, which winters near Japan and probably migrates to waters west of 
the Kodiak Archipelago (the Bering Sea and Aleutian Islands) in summer/
fall. Though there is some mixing between these populations, they are 
considered distinct stocks. The stock structure of humpback whales is 
defined based on feeding areas, as distinct populations have a high 
degree of fidelity to specific feeding areas. Humpback whales found in 
inland Washington waters are members of the CA/OR/WA stock. Carretta et 
al. (2011) described distinct feeding populations in the eastern 
Pacific, and the waters off northern Washington may be an area of 
mixing between the CA/OR/WA stock and British Columbia/Alaska whales, 
or whales in northern Washington and southern British Columbia may be a 
distinct feeding population and a separate stock.
    Status--Humpback whales were listed as endangered under the 
Endangered Species Preservation Act of 1966 because of declines due to 
commercial whaling. This protection was transferred to the ESA in 1973. 
Because of this listing, it is therefore designated as depleted and 
classified as a strategic stock under the MMPA. The recovery plan for 
humpback whales was finalized in November 1991 (NMFS, 1991). Critical 
habitat has not been designated for this species.
    Humpback whales are increasing in abundance through much of their 
range, including the CA/OR/WA stock. In the North Pacific, humpback 
abundance was estimated at fewer than 1,400 whales in 1966, after heavy 
commercial exploitation. The current abundance estimate for the North 
Pacific is about 20,000 whales in total. Carretta et al. (2011) 
reported the best estimate for the CA/OR/WA stock as 2,043 individuals, 
based on mark-recapture estimates by Calambokidis et al. (2009). 
However, this estimate excludes some whales in Washington. Population 
trends from mark-recapture estimates have shown an overall long-term 
increase of approximately 7.5 percent per year for the CA/OR/WA stock 
(Calambokidis, 2009).
    Distribution--The worldwide population of humpback whales is 
divided into various northern and southern ocean populations 
(Mackintosh, 1965). Geographical overlap of these populations has been 
documented only off Central America (Acevedo and Smultea, 1995; 
Rasmussen et al., 2004, 2007). The humpback whale is one of the most 
abundant cetaceans off the Pacific coast of Costa Rica during the 
winter breeding season of northern hemisphere humpbacks.
    Humpback whales were one of the most common large cetaceans in the 
inland waters of Washington prior to the early 1900s (Scheffer and 
Slipp, 1948). However, sightings became infrequent in Puget Sound and 
the Georgia Basin through the late 1990s, and prior to 2003 the 
presence of only three individual humpback whales was confirmed 
(Falcone et al., 2005). However, in 2003 and 2004, thirteen individuals 
were sighted in the inland waters of Washington, mainly during the fall 
(Falcone et al., 2005). Records available for 2001 to 2012 include 
observations in the Strait of Juan de Fuca; the Gulf Islands and the 
vicinity of Victoria, British Columbia; Admiralty Inlet; the San Juan 
Islands; Hood Canal; and Puget Sound (Orca Network, 2012).
    In Hood Canal, several humpback whale sightings were recorded 
beginning on January 27, 2012 (Orca Network, 2012). Review of the 
sightings information indicates the sightings are of a single 
individual. The most recent sighting reported was on February 17, 2012. 
It is currently unknown if this individual has left Hood Canal. Prior 
to these sightings, there have been no confirmed reports of humpback 
whales entering Hood Canal (Calambokidis, 2012). No other reports of 
humpback whales in the Hood Canal were found in the Orca Network 
database, the scientific literature, or agency reports. Construction of 
the Hood Canal Bridge occurred in 1961 and could have contributed to 
the lack of historical sightings (Calambokidis, 2010). Only a few 
records of humpback whales near Hood Canal are in the Orca Network 
database, but these are north of the Hood Canal Bridge.
    Behavior and Ecology--Humpback whales travel great distances during 
their seasonal migrations from high latitude feeding grounds to 
tropical and subtropical breeding grounds. One of the more closely 
studied routes is between Alaska and Hawaii, where humpbacks have been 
observed making the 3,000 mi (4,830 km) trip in as few as 36 days. 
During the summer months, humpbacks spend the majority of their time 
feeding and building up fat reserves (blubber) that they will live off 
of during the winter breeding season. Humpbacks filter feed on tiny 
crustaceans (mostly krill), plankton, and small fish and are known to 
consume up to 3,000 lb (1,360 kg) of food per day. Several hunting 
methods involve using air bubbles to herd, corral, or disorient fish. 
One highly complex variant, called bubble netting, is unique to 
humpbacks and is often performed in groups with defined roles for 
distracting, scaring, and herding before whales lunge at prey corralled 
near the surface. While on their winter breeding grounds, humpback 
whales congregate and engage in mating activities. Humpbacks are 
generally polygynous, with males exhibiting competitive behavior 
including aggressive and antagonistic displays. Breeding usually occurs 
once every 2 years, but sometimes occurs twice in 3 years.
    Although the humpback whale is considered a primarily coastal 
species, it often traverses deep pelagic areas while migrating (Clapham 
and Mattila, 1990; Norris et al., 1999; Calambokidis et al., 2001). 
During migration, humpbacks stay near the surface of the ocean, and 
tend to generally prefer shallow waters. During calving, humpbacks are 
usually found in the warmest waters available at that latitude. Calving 
grounds are commonly near offshore reef systems, islands, or 
continental shores. Humpback feeding grounds are in cold, productive 
coastal waters.
    Humpback whales are often sighted singly or in groups of two or 
three, but while on breeding and feeding grounds they may occur in 
groups larger than twenty (Leatherwood and Reeves, 1983; Jefferson et 
al., 2008). The diving behavior of humpback whales is related to time 
of year and whale activity (Clapham and Mead, 1999). In summer feeding 
areas, humpbacks typically forage in the upper 120 m of the water 
column, with a maximum recorded dive depth of 500 m (Dolphin, 1987; 
Dietz et al., 2002). On winter breeding grounds, humpback dives have 
been recorded at depths greater than 100 m (Baird et al., 2000). The 
CA/OR/WA stock winters in coastal Central America and Mexico, and the 
stock migrates to areas ranging from the coast of California to 
southern British Columbia in summer and fall.
    Acoustics--Humpback whales, like all baleen whales, are considered 
low-frequency cetaceans. Functional hearing for low-frequency cetaceans 
is estimated to range from 7 Hz to 22 kHz (Southall et al., 2007). 
During the winter breeding season, males sing complex songs that can 
last up to 20 minutes and be heard at great distance, and may sing for 
hours, repeating the song several times. All males in a population sing 
the same song, but that song continually evolves over time.

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,

[[Page 25420]]

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 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 whales tends to be more erect (straighter at 
the tip) than those of resident and offshore whales (Ford and Ellis, 
1999; Ford et al., 2000). Saddle patch pigmentation of transient killer 
whales is restricted to two patterns, and never has the large areas of 
black pigmentation intruding into the white of the saddle patch that is 
seen in resident and offshore types. Transient type whales are often 
found in long-term stable social units that tend to be smaller than 
resident social groups (e.g., fewer than ten whales); these social 
units do not seem as permanent as matrilines are in resident type 
whales. Transient killer whales feed nearly exclusively on marine 
mammals (Ford and Ellis, 1999), whereas resident whales primarily eat 
fish. Offshore whales are presumed to feed primarily on fish, and have 
been documented feeding on sharks.
    Within the transient type, association data (Ford et al., 1994; 
Ford and Ellis, 1999; Matkin et al., 1999), acoustic data (Saulitis, 
1993; Ford and Ellis, 1999) and genetic data (Hoelzel et al., 1998, 
2002; Barrett-Lennard, 2000) confirms that three communities of 
transient whales exist and represent three discrete populations: (1) 
Gulf of Alaska, Aleutian Islands, and Bering Sea transients, (2) AT1 
transients (Prince William Sound, AK; listed as depleted under the 
MMPA), and (3) West Coast transients. Among the genetically distinct 
assemblages of transient killer whales in the northeastern Pacific, 
only the West Coast transient stock, which occurs from southern 
California to southeastern Alaska, may occur in the project area.
    Status--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 a minimum number of 354 individuals 
for the West Coast transient stock (Allen and Angliss, 2010). However, 
the number in Washington waters at any one time is probably fewer than 
20 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. 
Population trends and status of this stock relative to its Optimum 
Sustainable Population (OSP) level are currently unknown.
    Distribution--The geographical range of transient killer whales 
includes the northeast Pacific, with preference for coastal waters of 
southern Alaska and British Columbia (Krahn et al., 2002). Transient 
killer whales in the eastern North Pacific spend most of their time 
along the outer coast, but visit Hood Canal and the Puget Sound in 
search of harbor seals, sea lions, and other prey. Transient occurrence 
in inland waters appears to peak during August and September (Morton, 
1990; Baird and Dill, 1995; Ford and Ellis, 1999) which is the peak 
time for harbor seal pupping, weaning, and post-weaning (Baird and 
Dill, 1995). In 2003 and 2005, small groups of transient killer whales 
(eleven and six individuals, respectively) visited Hood Canal to feed 
on harbor seals and remained in the area for significant periods of 
time (59 and 172 days, respectively) between the months of January and 
July.
    Behavior and Ecology--Transient killer whales show greater 
variability in habitat use, with some groups spending most of their 
time foraging in shallow waters close to shore while others hunt almost 
entirely in open water (Felleman et al., 1991; Baird and Dill, 1995; 
Matkin and Saulitis, 1997). Transient killer whales feed on marine 
mammals and some seabirds, but apparently no fish (Morton, 1990; Baird 
and Dill, 1996; Ford et al., 1998; Ford and Ellis, 1999; Ford et al., 
2005). While present in Hood Canal in 2003 and 2005, transient killer 
whales preyed on harbor seals in the subtidal zone of the nearshore 
marine and inland marine deeper water habitats (London, 2006). Other 
observations of foraging transient killer whales indicate they prefer 
to forage on pinnipeds in shallow, protected waters (Heimlich-Boran, 
1988; Saulitis et al., 2000). Transient killer whales travel in small, 
matrilineal groups, but they typically contain fewer than ten animals 
and their social organization generally is more flexible than that of 
resident killer whales (Morton, 1990, Ford and Ellis, 1999). These 
differences in social organization probably relate to differences in 
foraging (Baird and Whitehead, 2000). There is no information on the 
reproductive behavior of killer whales in this area.
    Acoustics--Killer whales produce a wide variety of clicks and 
whistles, but most of their sounds are pulsed, with frequencies ranging 
from 0.5-25 kHz (dominant frequency range: 1-6 kHz) (Thomson and 
Richardson, 1995; Richardson et al., 1995). Source levels of 
echolocation signals range between 195-224 dB re 1 [mu]Pa-m peak-to-
peak (p-p), dominant frequencies range from 20-60 kHz, with durations 
of about 0.1 s (Au et al., 2004). Source levels associated with social 
sounds have been calculated to range between 131-168 dB re 1 [mu]Pa-m 
and vary with vocalization type (Veirs, 2004).
    Both behavioral and auditory brainstem response techniques indicate 
killer whales can hear in a frequency range of 1-100 kHz and are most 
sensitive at 20 kHz. This is one of the lowest maximum-sensitivity 
frequencies known among toothed whales (Szymanski et al., 1999).

Dall's Porpoise

    Species Description--Dall's porpoises are members of the Phocoenid 
(porpoise) family and are common in the North Pacific Ocean. They can 
reach a maximum length of just under 8 ft (2.4 m) and weigh up to 480 
lb (218 kg). Males are slightly larger and thicker than females, which 
reach lengths of just under 7 ft (2.1 m) long. The body of Dall's 
porpoises is a very dark gray or black in coloration with variable 
contrasting white thoracic panels and white `frosting' on the dorsal 
fin and tail that distinguish them from other cetacean species. These 
markings and colorations vary with geographic region and life stage, 
with adults having more distinct patterns.

[[Page 25421]]

    Based on NMFS stock assessment reports, Dall's porpoises within the 
Pacific U.S. Exclusive Economic Zone are divided into two discrete, 
noncontiguous areas: (1) Waters off California, Oregon, and Washington, 
and (2) Alaskan waters (Carretta et al., 2008). Only individuals from 
the CA/OR/WA stock may occur within the project area.
    Status--The NMFS population estimate, recently updated in 2010 for 
the CA/OR/WA stock, is 42,000 (CV = 0.33) which is based on vessel line 
transect surveys by Barlow (2010) and Forney (2007). The minimum 
population is considered to be 32,106. Additional numbers of Dall's 
porpoises occur in the inland waters of Washington, but the most recent 
estimate was obtained in 1996 (900 animals; CV = 0.40; Calambokidis et 
al., 1997) and is not included in the overall estimate of abundance for 
this stock due to the need for more up-to-date information. Dall's 
porpoise are not listed as depleted under the MMPA or listed under the 
ESA. The average annual human-caused mortality is estimated to be less 
than the PBR, and therefore the stock is not classified as a strategic 
stock under the MMPA. The status of Dall's porpoises in California, 
Oregon and Washington relative to OSP is not known, and there are 
insufficient data to evaluate potential trends in abundance.
    Distribution--The Dall's porpoise is found from northern Baja 
California, Mexico, north to the northern Bering Sea and south to 
southern Japan (Jefferson et al., 1993). The species is only common 
between 32-62[deg] N in the eastern North Pacific (Morejohn, 1979; 
Houck and Jefferson, 1999). North-south movements in California, 
Oregon, and Washington have been suggested. Dall's porpoises shift 
their distribution southward during cooler-water periods (Forney and 
Barlow, 1998). Norris and Prescott (1961) reported finding Dall's 
porpoises in southern California waters only in the winter, generally 
when the water temperature was less than 15[deg]C (59[emsp14][deg]F). 
Seasonal movements have also been noted off Oregon and Washington, 
where higher densities of Dall's porpoises were sighted offshore in 
winter and spring and inshore in summer and fall (Green et al., 1992).
    In Washington, they are most abundant in offshore waters. They are 
year-round residents in Washington (Green et al., 1992), but their 
distribution is highly variable between years, likely due to changes in 
oceanographic conditions (Forney and Barlow, 1998). Dall's porpoises 
are observed throughout the year in the Puget Sound north of Seattle 
(Osborne et al., 1998) and are seen occasionally in southern Puget 
Sound. Dall's porpoises may also occasionally occur in Hood Canal 
(Jeffries 2006, personal communication). Nearshore habitats used by 
Dall's porpoises could include the marine habitats found in the inland 
marine waters of the Hood Canal. A Dall's porpoise was observed in the 
deeper water at NBKB in summer 2008 (Tannenbaum et al., 2009a).
    Behavior and Ecology--Dall's porpoises can be opportunistic feeders 
but primarily consume schooling forage fish. They are known to eat 
squid, crustaceans, and fishes such as blackbelly eelpout (Lycodopsis 
pacifica), herring, pollock, hake, and Pacific sandlance (Ammodytes 
hexapterus) (Walker et al., 1998). Groups of Dall's porpoises generally 
include fewer than ten individuals and are fluid, probably aggregating 
for feeding (Jefferson, 1990, 1991; Houck and Jefferson, 1999). Dall's 
porpoises become sexually mature at three and a half to eight years of 
age (Houck and Jefferson, 1999) and give birth to a single calf after 
ten to twelve months. Breeding and calving typically occurs in the 
spring and summer (Angell and Balcomb, 1982). In the North Pacific, 
there is a strong summer calving peak from early June through August 
(Ferrero and Walker, 1999), and a smaller peak in March (Jefferson, 
1989). Resident Dall's porpoises breed in Puget Sound from August to 
September.
    Acoustics--Only short duration pulsed sounds have been recorded for 
Dall's porpoises (Houck and Jefferson, 1999); this species apparently 
does not whistle often (Richardson et al., 1995). Dall's porpoises 
produce short duration (50-1,500 [mu]s), high-frequency, narrow band 
clicks, with peak energies between 120-160 kHz (Jefferson, 1988). There 
is no published data on the hearing abilities of this species.

Harbor Porpoise

    Species Description--Harbor porpoises belong to the Phocoenid 
(porpoise) family and are found extensively along the Pacific U.S. 
coast. Harbor porpoises are small, with males reaching average lengths 
of approximately 5 ft (1.5 m); Females are slightly larger with an 
average length of 5.5 ft (1.7 m). The average adult harbor porpoise 
weighs between 135-170 lb (61-77 kg). Harbor porpoises have a dark grey 
coloration on their backs, with their belly and throats white. They 
have a dark grey chin patch and intermediate shades of grey along their 
sides.
    Recent preliminary genetic analyses of samples ranging from 
Monterey, CA to Vancouver Island, BC indicate that there is small-scale 
subdivision within the U.S. portion of this range (Chivers et al., 
2002). Although geographic structure exists along an almost continuous 
distribution of harbor porpoises from California to Alaska, stock 
boundaries are difficult to draw because any rigid line is generally 
arbitrary from a biological perspective. Nevertheless, based on genetic 
data and density discontinuities identified from aerial surveys, NMFS 
identifies eight stocks in the Northeast Pacific Ocean. Pacific coast 
harbor porpoise stocks include: (1) Monterey Bay, (2) San Francisco-
Russian River, (3) northern California/southern Oregon, (4) Oregon/
Washington coastal, (5) inland Washington, (6) Southeast Alaska, (7) 
Gulf of Alaska, and (8) Bering Sea. Only individuals from the 
Washington Inland Waters stock may occur in the project area.
    Status--Aerial surveys of the inland waters of Washington and 
southern British Columbia were conducted during August of 2002 and 2003 
(J. Laake, unpubl. data). These aerial surveys included the Strait of 
Juan de Fuca, San Juan Islands, Gulf Islands, and Strait of Georgia, 
which includes waters inhabited by the Washington Inland Waters stock 
of harbor porpoises as well as harbor porpoises from British Columbia. 
An average of the 2002 and 2003 estimates of abundance in U.S. waters 
resulted in an uncorrected abundance of 3,123 (CV = 0.10) harbor 
porpoises in Washington inland waters (J. Laake, unpubl. data). When 
corrected for availability and perception bias, the estimated abundance 
for the Washington Inland Waters stock of harbor porpoise is 10,682 (CV 
= 0.38) animals (Carretta et al., 2008). The minimum population 
estimate is 7,841. Harbor porpoise are not listed as depleted under the 
MMPA or listed under the ESA. Based on currently available data, the 
total level of human-caused mortality is not known to exceed the PBR. 
Therefore, the Washington Inland Waters harbor porpoise stock is not 
classified as strategic. The status of this stock relative to its OSP 
level and population trends is unknown. Although long-term harbor 
porpoise sightings in southern Puget Sound have declined since the 
1940s, sightings have increased in Puget Sound and northern Hood Canal 
in recent years and are now considered to regularly occur year-round in 
these waters (Calambokidis, 2010). This may represent a return to 
historical conditions, when harbor porpoises were considered one of the

[[Page 25422]]

most common cetaceans in Puget Sound (Scheffer and Slipp, 1948).
    Distribution--Harbor porpoises are generally found in cool 
temperate to subarctic waters over the continental shelf in both the 
North Atlantic and North Pacific (Read, 1999). This species is seldom 
found in waters warmer than 17 [deg]C (63[emsp14][deg]F; Read, 1999) or 
south of Point Conception (Hubbs, 1960; Barlow and Hanan, 1995). Harbor 
porpoises can be found year-round primarily in the shallow coastal 
waters of harbors, bays, and river mouths (Green et al., 1992). Along 
the Pacific coast, harbor porpoises occur from Monterey Bay, California 
to the Aleutian Islands and west to Japan (Reeves et al., 2002). Harbor 
porpoises are known to occur in Puget Sound year round (Osmek et al., 
1996, 1998; Carretta et al., 2007), and harbor porpoise observations in 
northern Hood Canal have increased in recent years (Calambokidis, 
2010). Prior to recent construction projects conducted by the Navy at 
NBKB, harbor porpoises were considered as likely occurring only 
occasionally in the project area. A single harbor porpoise had been 
sighted in deeper water at NBKB during 2010 field observations (SAIC, 
2010). However, while implementing monitoring plans for work conducted 
from July-October, 2011, the Navy recorded multiple sightings of harbor 
porpoise in the deeper waters of the project area. Following these 
sightings, the Navy conducted dedicated line transect surveys, 
recording multiple additional sightings of harbor porpoise, and have 
revised local density estimates accordingly. The current density 
estimates are based upon a small sample size of transect surveys, and 
may be further revised as more information becomes available from 
ongoing Navy survey efforts.
    Behavior and Ecology--Harbor porpoises are non-social animals 
usually seen in small groups of two to five animals. Little is known 
about their social behavior. Harbor porpoises can be opportunistic 
foragers but primarily consume schooling forage fish (Osmek et al., 
1996; Bowen and Siniff, 1999; Reeves et al., 2002). Along the coast of 
Washington, harbor porpoises primarily feed on herring, market squid 
(Loligo opalescens) and eulachon (Thaleichthys pacificus) (Gearin et 
al., 1994). Females reach sexual maturity at three to four years of age 
and may give birth every year for several years in a row. Calves are 
born in late spring (Read, 1990; Read and Hohn, 1995). Dall's and 
harbor porpoises appear to hybridize relatively frequently in the Puget 
Sound area (Willis et al., 2004).
    Acoustics--Harbor porpoise vocalizations include clicks and pulses 
(Ketten, 1998), as well as whistle-like signals (Verboom and Kastelein, 
1995). The dominant frequency range is 110-150 kHz, with source levels 
of 135-177 dB re 1 [mu]Pa-m (Ketten, 1998). Echolocation signals 
include one or two low-frequency components in the 1.4-2.5 kHz range 
(Verboom and Kastelein, 1995).
    A behavioral audiogram of a harbor porpoise indicated the range of 
best sensitivity is 8-32 kHz at levels between 45-50 dB re 1 [mu]Pa-m 
(Andersen, 1970); however, auditory-evoked potential studies showed a 
much higher frequency of approximately 125-130 kHz (Bibikov, 1992). The 
auditory-evoked potential method suggests that the harbor porpoise 
actually has two frequency ranges of best sensitivity. More recent 
psycho-acoustic studies found the range of best hearing to be 16-140 
kHz, with a reduced sensitivity around 64 kHz (Kastelein et al., 2002). 
Maximum sensitivity occurs between 100-140 kHz (Kastelein et al., 
2002).

Potential Effects of the Specified Activity on Marine Mammals

    NMFS has determined that pile removal, as outlined in the project 
description, has the potential to result in behavioral harassment of 
marine mammals that may be swimming, foraging, or resting in the 
project vicinity while pile removal is being conducted. Pile removal 
could potentially harass those pinnipeds that are in the water close to 
the project site, whether their heads are above or below the surface.

Marine Mammal Hearing

    The primary effect on marine mammals anticipated from the specified 
activities would result from exposure of animals to underwater sound. 
Exposure to sound can affect marine mammal hearing. When considering 
the influence of various kinds of sound on the marine environment, it 
is necessary to understand that different kinds of marine life are 
sensitive to different frequencies of sound. Based on available 
behavioral data, audiograms derived using auditory evoked potential 
techniques, anatomical modeling, and other data, Southall et al. (2007) 
designate functional hearing groups for marine mammals and estimate the 
lower and upper frequencies of functional hearing of the groups. The 
functional groups and the associated frequencies are indicated below 
(though animals are less sensitive to sounds at the outer edge of their 
functional range and most sensitive to sounds of frequencies within a 
smaller range somewhere in the middle of their functional hearing 
range):
     Low frequency cetaceans (13 species of mysticetes): 
functional hearing is estimated to occur between approximately 7 Hz and 
22 kHz;
     Mid-frequency cetaceans (32 species of dolphins, six 
species of larger toothed whales, and nineteen species of beaked and 
bottlenose whales): Functional hearing is estimated to occur between 
approximately 150 Hz and 160 kHz;
     High frequency cetaceans (six species of true porpoises, 
four species of river dolphins, two members of the genus Kogia, and 
four dolphin species of the genus 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 and 75 kHz, with the greatest 
sensitivity between approximately 700 Hz and 20 kHz.
    As mentioned previously in this document, three pinniped and four 
cetacean species are likely to occur in the proposed project area. Of 
the four cetacean species likely to occur in the project area, two are 
classified as high frequency cetaceans (Dall's and harbor porpoises), 
one is classified as a mid-frequency cetacean (killer whales), and one 
is classified as a low-frequency cetacean (humpback whales) (Southall 
et al., 2007).

Underwater Sound Effects

    Potential Effects of Construction Sound--The effects of sounds from 
pile removal might--in theory, at least--result in one or more of the 
following: Temporary or permanent hearing impairment, non-auditory 
physical or physiological effects, behavioral disturbance, and masking 
(Richardson et al., 1995; Gordon et al., 2004; Nowacek et al., 2007; 
Southall et al., 2007). The effects of pile driving or removal on 
marine mammals are generally dependent on several factors, including 
the size, type, and depth of the animal; the depth, intensity, and 
duration of the pile removal 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 the proposed 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

[[Page 25423]]

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 remove the pile, which would 
ultimately decrease the intensity of the acoustic source.
    In the absence of mitigation, impacts to marine species would be 
expected to result from physiological and behavioral responses to both 
the type and strength of the acoustic signature (Viada et al., 2008). 
The type and severity of behavioral impacts are more difficult to 
define due to limited studies addressing the behavioral effects of 
underwater sounds on marine mammals. Potential effects from 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; O'Keefe and Young, 1984; DoN, 2001b).
    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, either permanently or 
temporarily. 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 is considered to 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; these effects are most frequently 
associated with pulsed sound, which would not occur during the proposed 
action. Some behavioral disturbance is expected, but it is likely that 
this would be localized and short-term because of the short project 
duration.
    In addition, given the low source levels expected in association 
with the non-pulsed sounds proposed for this activity, it is highly 
unlikely that any marine mammals could experience physiological effects 
or even TTS. All source levels for the proposed action would be less 
than 190 dB re: 1 [mu]Pa rms; therefore, there is no possibility of 
injury for pinnipeds. While vibratory pile removal is expected to 
produce sound equaling the 180 dB threshold for potential cetacean 
injury, that sound is expected to be restricted to a radius no more 
than 1 m (3.3 ft) from the pile removal, therefore essentially 
eliminating the possibility for cetacean injury, as it is extremely 
unlikely that any cetacean would approach so closely. Nevertheless, 
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 removal to avoid exposing them 
to sound that might, in theory, cause injury. The following subsection 
discusses TTS in somewhat more detail.
    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. Available data 
on TTS in marine mammals are summarized in Southall et al. (2007).

Disturbance Reactions

    Disturbance includes a variety of effects, including subtle changes 
in behavior, more conspicuous changes in activities, and displacement. 
Reactions to sound, if any, depend on species, state of maturity, 
experience, current activity, reproductive state, time of day, and many 
other factors (Richardson et al., 1995; Wartzok et al., 2004; Southall 
et al., 2007; Weilgart, 2007). Behavioral responses to sound are highly 
variable and context specific. For each potential behavioral change, 
the magnitude of the change ultimately determines the severity of the 
response. A number of factors may influence an animal's response to 
sound, including its previous experience, its auditory sensitivity, its 
biological and social status (including age and sex), and its 
behavioral state and activity at the time of exposure.
    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., 2003/04). 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., 2003/04). Controlled experiments with 
captive marine mammals showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). However, responses to non-pulsed sound, such as 
vibratory pile installation, have not been documented as well as 
responses to pulsed sounds.
    With both types of pile removal, it is likely that the onset of 
pile removal could result in temporary, short term changes in an 
animal's typical behavior and/or avoidance of the affected area. These 
behavioral changes may include (Richardson et al., 1995): Changing 
durations of surfacing and dives, number of blows per surfacing, or 
moving direction and/or speed; reduced/increased vocal activities; 
changing/cessation of certain behavioral activities (such as 
socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping); avoidance of 
areas where sound sources are located; and/or flight responses (e.g., 
pinnipeds flushing into water from haul-outs or rookeries). Pinnipeds 
may increase their haul-out time, possibly to avoid in-water 
disturbance (Caltrans 2001, 2006). Since pile removal 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 removal activities

[[Page 25424]]

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 removal 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 removal, and dredging activities, contribute to the 
elevated ambient sound levels, thus intensifying masking. However, the 
sum of sound from the proposed activities is confined in an area of 
inland waters (Hood Canal) that is bounded by landmass; therefore, the 
sound generated is not expected to contribute to increased ocean 
ambient sound.
    Typically, the most intense underwater sounds associated with 
marine construction are those produced by impact pile removal, which is 
not proposed for this action. However, the energy distribution of pile 
removal covers a broad frequency spectrum, and sound from these sources 
would likely be within the audible range of the marine mammals found in 
the Hood Canal. Vibratory pile removal is relatively short-term, with 
rapid oscillations occurring for approximately 1 hour per pile, with 
the total vibratory pile removal occurring for 15 days. The probability 
for vibratory pile removal masking acoustic signals important to the 
behavior and survival of marine mammal species is likely to be 
negligible. 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 pile removal, 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 removal that have the potential to 
cause harassment, depending on their distance from pile removal 
activities. Airborne pile removal sound would have less impact on 
cetaceans than pinnipeds because sound from atmospheric sources does 
not transmit well underwater (Richardson et al., 1995); thus, airborne 
sound would only be an issue for pinnipeds that are hauled-out or have 
their heads above water in the project area. Most likely, airborne 
sound would cause behavioral responses similar to those discussed above 
in relation to underwater sound. For instance, anthropogenic sound 
could cause hauled-out pinnipeds to exhibit changes in their normal 
behavior, such as reduction in vocalizations, or cause them to 
temporarily abandon their habitat and move further from the source. 
Studies by Blackwell et al. (2004) and Moulton et al. (2005) indicate a 
tolerance or lack of response to unweighted airborne sounds as high as 
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, such as haul-out 
sites, but may have potential short-term impacts to food sources such 
as forage fish and salmonids. There are no rookeries or major haul-out 
sites within 10 km (6.2 mi), foraging hotspots, or other ocean bottom 
structures of significant biological importance to marine mammals that 
may be 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 removal effects on likely marine mammal prey (i.e., fish) near 
NBKB and minor impacts to the immediate substrate during removal of 
piles during the wharf rehabilitation project.

[[Page 25425]]

Pile Removal Effects on Potential Prey (Fish)

    Construction activities would produce non-pulsed sounds. Fish react 
to sounds which are especially strong and/or intermittent low-frequency 
sounds which are generally unlike the sounds that would be produced by 
the proposed action. Short duration, sharp sounds can cause overt or 
subtle changes in fish behavior and local distribution. Hastings and 
Popper (2005, 2009) identified several studies that suggest fish may 
relocate to avoid certain areas of sound energy. SPLs of 180 dB may 
cause noticeable changes in behavior (Chapman and Hawkins, 1969; 
Pearson et al., 1992; Skalski et al., 1992). SPLs of sufficient 
strength have been known to cause injury to fish and fish mortality 
(Caltrans, 2001; Longmuir and Lively, 2001). The most likely impact to 
fish from pile removal activities at the project area would be 
temporary behavioral avoidance of the area. The duration of fish 
avoidance of this area after pile removal 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 and nature of sound 
produced for the project. Impacts could also result from potential 
impacts to fish eggs and larvae.

Pile Removal Effects on Potential Foraging Habitat

    The area likely impacted by the project is relatively small 
compared to the available habitat in the Hood Canal. 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 removal 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 Hood Canal and nearby vicinity.
    Given the short daily duration of sound associated with individual 
pile removal events and the relatively small areas being affected, pile 
removal 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 removal is not likely to have a 
permanent, adverse effect on marine mammal foraging habitat at the 
project area.

Previous Activity

    The proposed action for this IHA request represents the second year 
of a 2-year project. NMFS issued an IHA for the first year of work on 
May 24, 2011 (76 FR 30130). The Navy complied with the mitigation and 
monitoring required under the previous authorization. In accordance 
with the 2011 IHA, the Navy submitted a monitoring report, and the 
information contained therein was considered in this analysis. During 
the course of activities conducted under the previous authorization, 
the Navy did not exceed the take levels authorized under that IHA. 
Additional information regarding harbor porpoise, Steller sea lion, and 
humpback whale occurrence in the Hood Canal has been considered in this 
analysis.

Proposed Mitigation

    In order to issue an incidental take authorization (ITA) under 
section 101(a)(5)(D) of the MMPA, NMFS must, where applicable, 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).
    The modeling results for zones of influence (ZOIs; see ``Estimated 
Take by Incidental Harassment'') were used to develop mitigation 
measures for pile removal activities at NBKB. ZOIs are often used to 
effectively represent the mitigation zone that would be established 
around each pile to prevent Level A harassment of marine mammals, and 
also establish zones within which Level B harassment of marine mammals 
may occur. In addition to the measures described later in this section, 
the Navy would employ the following standard mitigation measures:
    (a) Conduct briefings between construction supervisors and crews, 
marine mammal monitoring team, acoustical monitoring team, and Navy 
staff prior to the start of all pile removal activity, and when new 
personnel join the work, in order to explain responsibilities, 
communication procedures, marine mammal monitoring protocol, and 
operational procedures.
    (b) Comply with applicable equipment sound standards and ensure 
that all construction equipment has sound control devices no less 
effective than those provided on the original equipment.
    (c) For in-water heavy machinery work other than pile removal, if a 
marine mammal comes within 10 m (33 ft), operations shall cease and 
vessels shall reduce speed to the minimum level required to maintain 
steerage and safe working conditions. This type of work could include, 
for example, movement of the barge to the pile location or removal of 
the pile from the water column/substrate via a crane (i.e., direct 
pull). For these activities, monitoring would take place from 15 
minutes prior to initiation until the action is complete.

Monitoring and Shutdown

    The following measures would apply to the Navy's mitigation through 
shutdown and disturbance zones:
    Shutdown Zone--For all pile removal activities, the Navy would 
establish a shutdown zone (defined as, at minimum, the area in which 
SPLs equal or exceed the 180/190 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. Although 
predictions indicate that radial distances to the 180/190-dB threshold 
would be less than 10 m--or would not exist because source levels are 
lower than the threshold--shutdown zones would conservatively be set at 
a minimum 10 m. This precautionary measure is intended to further 
reduce any possibility of injury to marine mammals by incorporating a 
buffer to the 180/190-dB threshold within the shutdown area.
    Disturbance Zone--For all pile removal activities, the Navy would 
establish a disturbance zone. Disturbance zones are typically defined 
as the area in which SPLs equal or exceed 120 dB rms (for non-pulsed 
sound). However, when the size of a disturbance zone is sufficiently 
large as to make monitoring of the entire area impracticable (as in the 
case of the vibratory removal zone here, predicted to encompass an area 
of 35.9 km\2\), the disturbance zone may be defined as some area that 
may reasonably be monitored. The Navy would establish an observation 
position within the Waterfront Restricted Area (WRA), maximally distant 
from the pile removal operations. The additional position would be able 
to monitor an effective area of at least 542 m distance (corresponding 
to the predicted radial distance to the 120-dB threshold for chipping) 
from the pile removal activity. In addition, the Navy would place a 
protected species observer (PSO) aboard

[[Page 25426]]

any vessel used outside the WRA for hydroacoustic monitoring, for the 
duration of any such monitoring. 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 PSOs 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). As with any such large action area, 
it is impossible to guarantee that all animals would be observed or to 
make comprehensive observations of fine-scale behavioral reactions to 
sound.
    All disturbance and shutdown zones would initially be based on the 
distances from the source that are predicted for each threshold level. 
However, should data from previously conducted acoustic monitoring 
(i.e., from monitoring of test pile or previous EHW-1 work), which is 
still in preparation, or from in-situ acoustic monitoring indicate that 
actual distances to these threshold zones are different, the size of 
the shutdown and disturbance zones would be adjusted accordingly.
    Monitoring Protocols--Monitoring would be conducted for a minimum 
10 m shutdown zone and a minimum approximate 600 m disturbance zone 
(although this may be larger for the duration of hydroacoustic 
monitoring) surrounding each pile for the presence of marine mammals 
before, during, and after pile removal activities. If a marine mammal 
is observed within the disturbance zone, a take would be recorded and 
behaviors documented. However, that pile segment would be completed 
without cessation, unless the animal approaches or enters the shutdown 
zone, at which point all pile removal activities would be halted.
    The disturbance zone was set at the largest area practicable for 
the Navy to maintain a monitoring presence over the duration of the 
activity. Sightings occurring outside this area (within the predicted 
35.9 km\2\ disturbance zone predicted for the vibratory removal 120-dB 
isopleths) would still be recorded and noted as a take, but detailed 
observations outside this zone would not be possible, and it would be 
impossible for the Navy to account for all individuals occurring in 
such a zone with any degree of certainty. Monitoring would take place 
from 15 minutes prior to initiation through 30 minutes post-completion 
of pile removal activities. Pile removal activities include the time to 
remove a single pile or series of piles, as long as the time elapsed 
between uses of the pile removal equipment is no more than 30 minutes.
    The following additional measures would apply to visual monitoring:
    (a) Monitoring would be conducted by qualified observers. 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.
    A trained observer would be placed from the best vantage point(s) 
practicable (e.g., from a small boat, the pile removal barge, on shore, 
or any other suitable location) to monitor for marine mammals and 
implement shutdown or delay procedures when applicable by calling for 
the shutdown to the equipment operator.
    (b) Prior to the start of pile removal activity, the shutdown zone 
would be monitored for 15 minutes to ensure that it is clear of marine 
mammals. Pile removal would only commence once observers have declared 
the shutdown zone clear of marine mammals; animals would be allowed to 
remain in the disturbance zone (i.e., must leave of their own volition) 
and their behavior would be monitored and documented.
    (c) If a marine mammal approaches or enters the shutdown zone 
during the course of pile removal operations, pile removal would 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.

Acoustic Measurements

    Acoustic measurements would be used to empirically verify the 
predicted shutdown and disturbance zones for pneumatic chipping. For 
further detail regarding the Navy's acoustic monitoring plan see 
``Proposed Monitoring and Reporting''.

Timing Restrictions

    The Navy has set timing restrictions for pile removal activities to 
avoid in-water work when ESA-listed fish populations are most likely to 
be present. The in-water work window for avoiding negative impacts to 
fish species is July 16-February 15.

Soft Start

    The use of a soft-start procedure is believed to provide additional 
protection to marine mammals by warning, or providing marine mammals a 
chance to leave the area prior to the hammer operating at full 
capacity. The wharf rehabilitation project would utilize soft-start 
techniques for vibratory pile removal. The soft-start requires 
contractors to initiate sound from vibratory hammers for fifteen 
seconds at reduced energy followed by a 30-second waiting period. This 
procedure would be repeated two additional times.

Daylight Construction

    Pile removal and other in-water work would occur only during 
daylight hours (i.e., civil dawn to civil dusk).

Mitigation Effectiveness

    It should be recognized that although marine mammals would be 
protected through the use of measures described here, the efficacy of 
visual detection depends on several factors including the observer's 
ability to detect the animal, the environmental conditions (visibility 
and sea state), and monitoring platforms. All observers utilized for 
mitigation activities would be experienced biologists with training in 
marine mammal detection and behavior.

[[Page 25427]]

Trained observers have specific knowledge of marine mammal physiology, 
behavior, and life history, which may improve their ability to detect 
individuals or help determine if observed animals are exhibiting 
behavioral reactions to construction activities.
    The Puget Sound region, including the Hood Canal, only infrequently 
experiences winds with velocities in excess of 25 kn (Morris et al., 
2008). The typically light winds afforded by the surrounding highlands 
coupled with the fetch-limited environment of the Hood Canal result in 
relatively calm wind and sea conditions throughout most of the year. 
The wharf rehabilitation project site has a maximum fetch of 8.4 mi 
(13.5 km) to the north, and 4.2 mi (6.8 km) to the south, resulting in 
maximum wave heights of from 2.85-5.1 ft (0.9-1.6 m) (Beaufort Sea 
State (BSS) between two and four), even in extreme conditions (30 kt 
winds) (CERC, 1984). Visual detection conditions are considered optimal 
in BSS conditions of three or less, which align with the conditions 
that should be expected for the wharf rehabilitation project at NBKB.
    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of 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, including 
consideration of personnel safety, and practicality of implementation.
    Based on our evaluation of the applicant's proposed measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on marine 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 NMFS must, where applicable, 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 would 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.

Acoustic Monitoring

    The Navy would conduct acoustic monitoring for pneumatic chipping 
of concrete piles to determine the actual distances to the 120 dB re 1 
[mu]Pa rms isopleths for behavioral harassment relative to background 
levels. Underwater sound levels were measured at the project site in 
2011 in the absence of construction activities to determine background 
sound levels and, therefore, will not be recorded again during this 
work window. Airborne acoustic monitoring would be conducted during 
pile removal through chipping to identify the actual distance to the 90 
dB re 20 [mu]Pa rms and 100 dB re 20 [mu]Pa rms airborne isopleths.
    At a minimum, the methodology would include:
     Acoustic monitoring will be conducted on a minimum of five 
concrete piles.
     For underwater recordings, a stationary hydrophone system 
with the ability to measure SPLs will be placed in accordance with 
NMFS' most recent guidance for collection of source levels.
     For airborne recordings, reference recordings will be 
attempted at approximately 50 ft (15.2 meters) from the source via a 
stationary hydrophone. However, other distances may be utilized to 
obtain better data if the signal cannot be isolated clearly due to 
other sound sources (i.e., barges or generators).
     Each hydrophone (underwater) and microphone (airborne) 
will be calibrated prior to the start of the action and will be checked 
at the beginning of each day of monitoring activity. Other hydrophones 
will be placed at other distances and/or depths as necessary to 
determine the distance to the thresholds for marine mammals.
     Environmental data will be collected including but not 
limited to: Wind speed and direction, wave height, water depth, 
precipitation, and type and location of in-water construction 
activities, as well as other factors that could contribute to 
influencing the airborne and underwater sound levels (e.g. aircraft, 
boats);
     The construction contractor will supply the Navy and other 
relevant monitoring personnel with the substrate composition, hammer 
model and size, hammer energy settings and any changes to those 
settings during the piles being monitored.
     For acoustically monitored piles, post-analysis of the 
sound level signals will include the average, minimum, and maximum rms 
value for each pile monitored during removal. A frequency spectrum will 
also be provided for the pneumatic chipping signal.
     Airborne levels would be recorded as an unweighted time 
series. The distance to marine mammal airborne sound disturbance 
thresholds would be determined.

Visual Monitoring

    The Navy would 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 would be trained 
in marine mammal identification and behaviors. NMFS requires that the 
observers have no other construction-related tasks while conducting 
monitoring.
    Methods of Monitoring--The Navy would monitor the shutdown zone and 
disturbance zone before, during, and after pile removal. There would, 
at all times, be at least one observer stationed at an appropriate 
vantage point to observe the shutdown zones associated with each 
operating hammer. There would also at all times be at least one vessel-
based observer stationed within the WRA. In addition, at least one 
marine mammal observer would be stationed on any vessel conducting 
acoustic monitoring outside the WRA, for as long as such monitoring is 
conducted. Based on NMFS requirements, the Marine Mammal Monitoring 
Plan would include the following procedures for pile removal:
    (1) 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. This may require the use of a small boat to monitor 
certain areas while also monitoring from one or more land based vantage 
points.
    (2) During all observation periods, observers would use binoculars 
and the naked eye to search continuously for marine mammals.
    (3) If the shutdown or disturbance zones are obscured by fog or 
poor lighting conditions, pile removal at that location would not be 
initiated until that zone is visible.
    (4) The shutdown and disturbance zones around the pile would be

[[Page 25428]]

monitored for the presence of marine mammals before, during, and after 
any pile removal activity.
    Pre-Activity Monitoring--The shutdown and disturbance zones would 
be monitored for 15 minutes prior to initiating pile removal. If marine 
mammal(s) are present within the shutdown zone prior to pile removal, 
or during the soft start, the start of pile removal would be delayed 
until the animal(s) leave the shutdown zone. Pile removal would resume 
only after the PSO has determined, through observation or by waiting 15 
minutes, that the animal(s) has moved outside the shutdown zone.
    During Activity Monitoring--The shutdown and disturbance zones 
would also be monitored throughout the time required to remove a pile. 
If a marine mammal is observed entering the disturbance zone, a take 
would be recorded and behaviors documented. However, that pile segment 
would be completed without cessation, unless the animal enters or 
approaches the shutdown zone, at which point all pile removal 
activities would be halted. Pile removal can only resume once the 
animal has left the shutdown zone of its own volition or has not been 
resighted for a period of 15 minutes.
    Post-Activity Monitoring--Monitoring of the shutdown and 
disturbance zones would continue for 30 minutes following the 
completion of pile removal.
    Individuals implementing the monitoring protocol would assess its 
effectiveness using an adaptive approach. Monitoring biologists would 
use their best professional judgment throughout implementation and 
would seek improvements to these methods when deemed appropriate. Any 
modifications to protocol would be coordinated between the Navy and 
NMFS.

Data Collection

    NMFS requires that the PSOs use NMFS-approved sighting forms. In 
addition to the following requirements, the Navy would note in their 
behavioral observations whether an animal remains in the project area 
following a Level B taking (which would not require cessation of 
activity). This information would ideally make it possible to determine 
whether individuals are taken (within the same day) by one or more 
types of pile removal. NMFS requires that, at a minimum, the following 
information be collected on the sighting forms:
    (1) Date and time that pile removal begins or ends;
    (2) Construction activities occurring during each observation 
period;
    (3) Weather parameters identified in the acoustic monitoring (e.g., 
percent cover, visibility);
    (4) Water conditions (e.g., sea state, tide state);
    (5) Species, numbers, and, if possible, sex and age class of marine 
mammals;
    (6) Marine mammal behavior patterns observed, including bearing and 
direction of travel, and if possible, the correlation to SPLs;
    (7) Distance from pile removal activities to marine mammals and 
distance from the marine mammals to the observation point;
    (8) Locations of all marine mammal observations; and
    (9) Other human activity in the area.

Reporting

    A draft acoustic monitoring report would be submitted to NMFS 
within 90 calendar days of the completion of the acoustic measurements. 
Separately, a draft marine mammal monitoring report would be submitted 
within 90 calendar days of the completion of construction activity. The 
report would include marine mammal observations pre-activity, during-
activity, and post-activity during pile removal days. Final reports 
would be prepared and submitted to NMFS within 30 days following 
receipt of comments on the draft report from NMFS. At a minimum, the 
reports would include:
     Date and time of activity;
     Water and weather conditions (e.g., sea state, tide state, 
percent cover, visibility);
     Description of the pile removal activity (e.g., size and 
type of piles, machinery used);
     The vibratory hammer force or chipping hammer setting used 
to extract the piles;
     A description of the monitoring equipment;
     The distance between hydrophone(s) and pile;
     The depth of the hydrophone(s);
     The physical characteristics of the bottom substrate from 
which the pile was extracted (if possible);
     The rms range and mean for each monitored pile;
     The results of the acoustic measurements, including the 
frequency spectrum, peak and rms SPLs for each monitored pile;
     The results of the airborne sound measurements (unweighted 
levels);
     Date and time observation is initiated and terminated;
     A description of any observable marine mammal behavior in 
the immediate area and, if possible, the correlation to underwater 
sound levels occurring at that time;
     Actions performed to minimize impacts to marine mammals;
     Times when pile removal is stopped due to presence of 
marine mammals within shutdown zones and time when pile removal 
resumes;
     Results, including the detectability of marine mammals, 
species and numbers observed, sighting rates and distances, behavioral 
reactions within and outside of shutdown zones; and
     A refined take estimate based on the number of marine 
mammals observed in the shutdown and disturbance zones.

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 remote. However, it is unlikely that injurious 
or lethal takes would occur even in the absence of the planned 
mitigation and monitoring measures.
    If a marine mammal responds to an underwater sound 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. 
For example, during the past 10 years, killer

[[Page 25429]]

whales have been observed within the project area twice. On the basis 
of that information, an estimated amount of potential takes for killer 
whales is presented here. However, while a pod of killer whales could 
potentially visit again during the project timeframe, and thus be 
taken, it is more likely that they would not.
    The proposed project area is not believed to be particularly 
important habitat for marine mammals, although harbor seals are year-
round residents of Hood Canal and sea lions are known to haul-out on 
submarines and other man-made objects at the NBKB waterfront (although 
typically at a distance of a mile or greater from the project site). 
Therefore, behavioral disturbances that could result from anthropogenic 
sound associated with the proposed activities are expected to affect 
only a relatively small number of individual marine mammals, although 
those effects could be recurring if the same individuals remain in the 
project vicinity.
    The Navy is requesting authorization for the potential taking of 
small numbers of Steller sea lions, California sea lions, harbor seals, 
transient killer whales, Dall's porpoises, and harbor porpoises in the 
Hood Canal that may result from pile removal during construction 
activities associated with the wharf rehabilitation project described 
previously in this document. No incidental take of humpback whale is 
predicted. The takes requested are expected to have no more than a 
minor effect on individual animals and no effect at the population 
level for these species. Any effects experienced by individual marine 
mammals are anticipated to be limited to short-term disturbance of 
normal behavior or temporary displacement of animals near the source of 
the sound.

Marine Mammal Densities

    For all species, the best scientific information available was used 
to construct density estimates or estimate local abundance. Of 
available information deemed suitable for use, the data that produced 
the most conservative (i.e., highest) density or abundance estimate for 
each species was used. For harbor seals, this involved published 
literature describing harbor seal research conducted in Washington and 
Oregon as well as more specific counts conducted in Hood Canal (Huber 
et al., 2001; Jeffries et al., 2003). Killer whales are known from two 
periods of occurrence (2003 and 2005) and are not known to 
preferentially use any specific portion of the Hood Canal. Therefore, 
density was calculated as the maximum number of individuals present at 
a given time during those occurrences (London, 2006), divided by the 
area of Hood Canal. The best information available for the remaining 
species in Hood Canal came from surveys conducted by the Navy at the 
NBKB waterfront or in the vicinity of the project area. These consist 
of three discrete sets of survey effort, and are described here in 
greater detail.
    Beginning in April 2008, Navy personnel have recorded sightings of 
marine mammals occurring at known haul-outs along the NBKB waterfront, 
including docked submarines or other structures associated with NBKB 
docks and piers and the nearshore pontoons of the floating security 
fence. Sightings of marine mammals within the waters adjoining these 
locations were also recorded. Sightings were attempted whenever 
possible during a typical work week (i.e., Monday through Friday), but 
inclement weather, holidays, or security constraints often precluded 
surveys. These sightings took place frequently (average fourteen per 
month) although without a formal survey protocol. During the surveys, 
staff visited each of the above-mentioned locations and recorded 
observations of marine mammals. Surveys were conducted using binoculars 
and the naked eye from shoreline locations or the piers/wharves 
themselves. Because these surveys consist of opportunistic sighting 
data from shore-based observers, largely of hauled-out animals, there 
is no associated survey area appropriate for use in calculating a 
density from the abundance data. Thus, NMFS has not used these data to 
derive a density but rather has used the absolute abundance to estimate 
take. For analysis in this proposed IHA, data were compiled for the 
period from April 2008 through June 2010--with the additional inclusion 
of twelve surveys from October 2011 in which only Steller sea lion 
observations were recorded, as this was the first record of Steller sea 
lion presence during the month of October--and these data provided the 
basis for take estimation for Steller and California sea lions. Other 
information, including sightings data from other Navy survey efforts at 
NBKB, is available for these two species, but these data provide the 
most conservative (i.e., highest) local abundance estimates (and thus 
the highest estimates of potential take). For all other species, the 
data source that provided the most conservative density estimate was 
used.
    Vessel-based marine wildlife surveys were conducted according to 
established survey protocols during July through September 2008 and 
November through May 2009-10 (Tannenbaum et al., 2009, 2011). Eighteen 
complete surveys of the nearshore area resulted in observations of four 
marine mammal species (harbor seal, California sea lion, harbor 
porpoise, and Dall's porpoise). These surveys operated along pre-
determined transects parallel to the shoreline from the nearshore out 
to approximately 1,800 ft (549 m) from shoreline, at a spacing of 100 
yd (91 m), and covered the entire NBKB waterfront (approximately 3.9 
km\2\ per survey) at a speed of 5 kn or less. Two observers recorded 
sightings of marine mammals both in the water and hauled out, including 
date, time, species, number of individuals, age (juvenile, adult), 
behavior (swimming, diving, hauled out, avoidance dive), and haul-out 
location. Positions of marine mammals were obtained by recording 
distance and bearing to the animal with a rangefinder and compass, 
noting the concurrent location of the boat with GPS, and, subsequently, 
analyzing these data to produce coordinates of the locations of all 
animals detected. These surveys produced the information used to 
estimate take for Dall's porpoise.
    During 2011 construction activities, marine mammal monitoring was 
conducted on construction days for mitigation purposes. During those 
efforts, the Navy observed that harbor porpoises were more common in 
deeper waters of Hood Canal than the previously described, nearshore 
vessel-based surveys indicated. For that reason, the Navy conducted 
vessel-based line transect surveys in Hood Canal on days when no 
construction activities occurred in order to collect additional density 
data for species present in Hood Canal. These surveys were primarily 
conducted in September and detected three marine mammal species (harbor 
seal, California sea lion, and harbor porpoise), and included surveys 
conducted in both the main body of Hood Canal, near the project area, 
and baseline surveys conducted for comparison in Dabob Bay, an area of 
Hood Canal that is not affected by sound from Navy actions at the NBKB 
waterfront (see Figures 2-1 and 4-1 in the Navy's application). The 
surveys operated along pre-determined transects that followed a double 
saw-tooth pattern to achieve uniform coverage of the entire NBKB 
waterfront. The vessel traveled at a speed of approximately 5 kn when 
transiting along the transect lines. Two observers recorded sightings 
of marine mammals both in the water and hauled out, including the date, 
time, species, number of individuals,

[[Page 25430]]

and behavior (swimming, diving, etc.). Positions of marine mammals were 
obtained by recording the distance and bearing to the animal(s), noting 
the concurrent location of the boat with GPS, and subsequently 
analyzing these data to produce coordinates of the locations of all 
animals detected. Sighting information for harbor porpoises was 
corrected for detectability (g(0) = 0.54; Barlow, 1988; Calambokidis et 
al., 1993; Carretta et al., 2001). Distance sampling methodologies were 
used to estimate densities of animals for these data. Due to the recent 
execution of these surveys, not all data have been processed. Due to 
the unexpected abundance of harbor porpoises encountered, data for this 
species were processed first and are available for use in this proposed 
IHA. All other species data may be included in subsequent environmental 
compliance documents once all post-processing is complete, but 
preliminary analysis indicates that use of the previously described 
data would still provide the most conservative take estimates for the 
other species.
    The cetaceans, as well as the harbor seal, appear to range 
throughout Hood Canal; therefore, the analysis in this proposed IHA 
assumes that harbor seal, humpback whale, transient killer whale, 
harbor porpoise, and Dall's porpoise are uniformly distributed in the 
project area. However, it should be noted that there have been no 
observations of cetaceans within the WRA security barrier; the barrier 
thus appears to effectively prevent cetaceans from approaching the 
shutdown zones (please see Figure 6-2 of the Navy's application; the 
WRA security barrier, which is not denoted in the figure legend, is 
represented by a thin gray line). Although source levels associated 
with the proposed actions are so low that no Level A harassments would 
likely occur even in the absence of any mitigation measures, it appears 
that cetaceans at least are not at risk of Level A harassment at NBKB 
even from louder activities (e.g., impact pile driving). The remaining 
species that occur in the project area, Steller sea lion and California 
sea lion, do not appear to utilize most of Hood Canal. The sea lions 
appear to be attracted to the man-made haul-out opportunities along the 
NBKB waterfront while dispersing for foraging opportunities elsewhere 
in Hood Canal. California sea lions were not reported during aerial 
surveys of Hood Canal (Jeffries et al., 2000), and Steller sea lions 
have only been documented at the NBKB waterfront.

Description of Take Calculation

    The take calculations presented here rely on the best data 
currently available for marine mammal populations in the Hood Canal, as 
discussed in preceding sections. The formula was developed for 
calculating take due to pile removal activity and applied to each 
group-specific sound impact threshold. The formula is founded on the 
following assumptions:
     All pilings to be installed would have a sound disturbance 
distance equal to that of the piling that causes the greatest sound 
disturbance (i.e., the piling furthest from shore);
     All marine mammal individuals potentially available are 
assumed to be present within the relevant area, and thus incidentally 
taken; and,
     An individual can only be taken once during a 24-hour 
period.

The calculation for marine mammal takes is estimated by:
    Take estimate = (n * ZOI) * days of total activity

Where:

n = density estimate used for each species/season
ZOI = sound threshold zone of influence (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 Tables 2 and 4 (actual distances 
rather than modeled) were used to calculate ZOI around each pile. The 
ZOI impact area took into consideration the possible affected area of 
the Hood Canal from the pile removal site furthest from shore with 
attenuation due to land shadowing from bends in the canal. Because of 
the close proximity of some of the piles to the shore, the narrowness 
of the canal at the project area, and the maximum fetch, the ZOIs for 
each threshold are not necessarily spherical and may be truncated.
    For sea lions, as described previously, the surveys offering the 
most conservative estimates of abundance do not have a defined survey 
area and so are not suitable for deriving a density construct. Instead, 
abundance is estimated on the basis of previously described 
opportunistic sighting information at the NBKB waterfront, and it is 
assumed that the total amount of animals known from NBKB haul-outs 
would be ``available'' to be taken in a given pile removal day. Thus, 
for these two species, take is estimated by multiplying abundance by 
days of activity.
    The total number of days spent removing piles is expected to be a 
maximum of 15 for vibratory removal and 32 for chipping. While pile 
removal can occur any day throughout the in-water work window, and the 
analysis is conducted on a per day basis, only a fraction of that time 
is actually spent in pile removal. For each pile, vibratory pile 
removal is expected to be no more than 1 hour. Pneumatic chipping is 
expected to take approximately 2 hours per pile.
    The exposure assessment methodology is an estimate of the numbers 
of individuals exposed to the effects of pile removal activities 
exceeding NMFS-established thresholds. Of note in these exposure 
estimates, mitigation methods (i.e., visual monitoring and the use of 
shutdown zones) were not quantified within the assessment and 
successful implementation of this mitigation is not reflected in 
exposure estimates. Results from acoustic impact exposure assessments 
should be regarded as conservative estimates.
    Airborne Sound--No incidents of incidental take are predicted as a 
result of exposure to airborne sound, using the formula given in this 
section and the information from Table 4. This is primarily due to the 
low source levels associated with the specified activities. However, it 
is NMFS' view that authorization for incidental take resulting from 
exposure to airborne sound, in the absence of any haul-outs or 
opportunities for an animal to haul out within the ZOI, would 
effectively result in double counting. Such exposure results when 
pinnipeds raise their heads above water; thus, those individuals are 
within the larger ZOI corresponding to Level B harassment resulting 
from underwater sound produced by the same source, and are already 
exposed and considered as an incidental take. As noted previously, NMFS 
considers an individual as able to be incidentally taken once per 24-
hour period. 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.

California Sea Lion

    California sea lions are present in Hood Canal during much of the 
year with the exception of mid-June through August. California sea 
lions occur regularly in the vicinity of the project

[[Page 25431]]

site from September through mid-June, as determined by Navy waterfront 
surveys conducted from April 2008 through June 2010 (Navy, 2010; Table 
6). With regard to the range of this species in Hood Canal and the 
project area, it is assumed on the basis of waterfront observations 
(Agness and Tannenbaum, 2009; Tannenbaum et al., 2009, 2011) that the 
opportunity to haul out on submarines docked at Delta Pier is a primary 
attractant for California sea lions in Hood Canal, as they have rarely 
been reported, either hauled out or swimming, elsewhere in Hood Canal 
(Jeffries, 2007). Abundance is calculated as the monthly average of the 
maximum number observed in a given month, as opposed to the overall 
average (Table 6). For example, in the month of May, the maximum number 
of animals observed on any one day was 25 in 2008, 33 in 2009, and 17 
in 2010, providing a monthly average of the maximum daily number 
observed of 25. This provides a conservative overall daily abundance of 
26.2 for the in-water work window, as compared with an actual per 
survey abundance of 11.4 during the same period.

                Table 6--California Sea Lion Sighting Information From NBKB, April 2008-June 2010
----------------------------------------------------------------------------------------------------------------
                                                                Number of
                  Month                       Number of       surveys with      Frequency of      Abundance \2\
                                               surveys       animals present    presence \1\
----------------------------------------------------------------------------------------------------------------
January.................................                25                15              0.60              24.0
February................................                28                24              0.86              31.0
March...................................                28                26              0.93              38.5
April...................................                38                27              0.71              36.3
May.....................................                44                34              0.77              25.0
June....................................                44                 7              0.16               5.3
July....................................                31                 0                 0                 0
August..................................                29                 1              0.03               0.5
September...............................                26                 9              0.35              22.0
October.................................                26                22              0.85              45.5
November................................                22                22                 1              54.0
December................................                24                14              0.58              32.5
                                         -----------------------------------------------------------------------
    Total or average (in-water work                    211               107              0.53              26.2
     season only).......................
----------------------------------------------------------------------------------------------------------------
Totals (number of surveys) and averages (frequency and abundance) presented for in-water work season (July-
  February) only. Information from March-June presented for reference.
\1\ Frequency is the number of surveys with California sea lions present/number of surveys conducted.
\2\ Abundance is calculated as the monthly average of the maximum daily number observed in a given month.

    The largest observed number of California sea lions hauled out 
along the NBKB waterfront was 58 in a November survey. During the in-
water construction period (mid-July to mid-February) the largest daily 
attendance average for each month ranged from 24 individuals to 54 
individuals. The likelihood of California sea lions being present at 
NBKB is greatest from October through May, when the frequency of 
attendance in surveys was at least 0.58. Attendance along the NBKB 
waterfront in November surveys (2008-09) was 100 percent. Additionally, 
five navigational buoys near the entrance to Hood Canal were documented 
as potential haul-outs, each capable of supporting three adult 
California sea lions (Jeffries et al., 2000). Breeding rookeries are in 
California; therefore, pups are not expected to be present in Hood 
Canal (NMFS 2008b). Female California sea lions are rarely observed 
north of the California/Oregon border; therefore, only adult and sub-
adult males are expected to be exposed to project impacts.
    The ZOI for vibratory removal encompasses areas where California 
sea lions are known to haul-out; assuming that 26 individuals could be 
taken per day of vibratory removal provides an estimate of 390 takes 
for that activity. The ZOI for pneumatic chipping does not encompass 
areas where California sea lions are known to occur; nevertheless, it 
is likely that some individuals would transit this area in route to 
haul out or forage. Therefore, and in order to ensure that the Navy is 
adequately authorized for incidental take, NMFS predicts that at least 
one individual California sea lion could be exposed to sound levels 
indicating Level B harassment per day of pneumatic chipping. Table 8 
depicts the estimated number of behavioral harassments.

Steller Sea Lion

    Steller sea lions were first documented at the NBKB waterfront in 
November 2008, while hauled out on submarines at Delta Pier 
(Bhuthimethee, 2008; Navy, 2010) and have been periodically observed 
since that time. Steller sea lions typically occur at NBKB from 
November through April; however, the first October sightings of Steller 
sea lions at NBKB occurred in 2011. Based on waterfront observations, 
Steller sea lions appear to use available haul-outs (typically in the 
vicinity of Delta Pier, approximately one mile south of the project 
area) and habitat similarly to California sea lions, although in lesser 
numbers. On occasions when Steller sea lions are observed, they 
typically occur in mixed groups with California sea lions also present, 
allowing observers to confirm their identifications based on 
discrepancies in size and other physical characteristics. During 
October 2011, up to four individuals were sighted either hauled out at 
the submarines docked at Delta Pier or swimming in the waters just 
adjacent to those haul-outs.
    Vessel-based survey effort in NBKB nearshore waters have not 
detected any Steller sea lions (Agness and Tannenbaum, 2009; Tannenbaum 
et al., 2009, 2011). Opportunistic sightings data provided by Navy 
personnel since April 2008 have continued to document sightings of 
Steller sea lions at Delta Pier from November through April (Table 7). 
Steller sea lions have only been observed hauled out on submarines 
docked at Delta Pier. Delta Pier and other docks at NBKB are not 
accessible to pinnipeds due to the height above water, although the 
smaller California sea lions and harbor seals are able to haul out on 
pontoons that support the floating security barrier. One to two animals 
are typically seen hauled out with California sea lions; the maximum 
Steller sea lion group size seen at any given time was six individuals 
in November 2009.

[[Page 25432]]



          Table 9--Steller Sea Lion Sighting Information From NBKB, April 2008-June 2010; October 2011
----------------------------------------------------------------------------------------------------------------
                                                                Number of
                  Month                       Number of       surveys with      Frequency of      Abundance \2\
                                               surveys       animals present    presence \1\
----------------------------------------------------------------------------------------------------------------
January.................................                25                 4              0.16               1.0
February................................                28                 1              0.04               0.5
March...................................                28                 4              0.14               1.0
April...................................                38                 5              0.13               1.3
May.....................................                44                 0                 0                 0
June....................................                44                 0                 0                 0
July....................................                31                 0                 0                 0
August..................................                29                 0                 0                 0
September...............................                26                 0                 0                 0
October.................................                38                12              0.32               1.3
November................................                22                 3              0.14               5.0
December................................                24                 5              0.21               1.5
                                         -----------------------------------------------------------------------
    Total or average....................               223                25              0.11               1.2
    (in-water work season only).........
----------------------------------------------------------------------------------------------------------------
Totals (number of surveys) and averages (frequency and abundance) presented for in-water work season (July-
  February) only. Information from March-June presented for reference.
\1\ Frequency is the number of surveys with Steller sea lions present/number of surveys conducted.
\2\ Abundance is calculated as the monthly average of the maximum daily number observed in a given month.

    Their frequency of occurrence by month typically has not exceeded 
0.21 (in December 2009), i.e., they were present in only 21 percent of 
surveys that month. However, all 12 surveys conducted in October 2011 
resulted in Steller sea lion sightings, raising the frequency of 
occurrence for that month to 0.32. The time period from November 
through April coincides with the time when Steller sea lions are 
frequently observed in Puget Sound. Only adult and sub-adult males are 
likely to be present in the project area during this time; female 
Steller sea lions have not been observed in the project area. Since 
there are no known breeding rookeries in the vicinity of the project 
site, Steller sea lion pups are not expected to be present. By May, 
most Steller sea lions have left inland waters and returned to their 
rookeries to mate. Although sub-adult individuals (immature or pre-
breeding animals) will occasionally remain in Puget Sound over the 
summer, observational data (Table 7) have indicated that Steller sea 
lions are present only from October through April and not during the 
summer months.
    Local abundance information, rather than density, was used in 
estimating take for Steller sea lions. Please see the discussion 
provided previously for California sea lions. Steller sea lions are 
known only from haul-outs over one mile from the project area, and 
would not be subject to harassment from airborne sound. The ZOI for 
vibratory removal encompasses areas where Steller sea lions are known 
to haul-out; assuming that one individual could be taken per day of 
vibratory removal provides an estimate of fifteen takes for that 
activity. However, the available abundance information does not reflect 
the nature of Steller sea lion occurrence at NBKB. According to the 
most recent observational information, if Steller sea lions are present 
at NBKB, it is possible that as many as four individuals could be 
present on submarines docked at Delta Pier or in waters adjacent to 
these haul-outs. Thus, NMFS conservatively assumes that up to four 
individuals could be exposed to sound levels indicating Level B 
harassment per day of vibratory pile removal. Similar to California sea 
lions, the ZOI for pneumatic chipping does not encompass areas where 
Steller sea lions are known to occur; nevertheless, it is possible that 
some individuals could transit this area in route to haul out or 
forage. Therefore, and in order to ensure that the Navy is adequately 
authorized for incidental take, NMFS predicts that at least one 
individual Steller sea lion could be exposed to sound levels indicating 
Level B harassment per day of pneumatic chipping. Table 8 depicts the 
number of estimated behavioral harassments.

Harbor Seal

    Harbor seals are the most abundant marine mammal in Hood Canal, 
where they can occur anywhere in Hood Canal waters year-round. The Navy 
detected harbor seals during marine mammal boat surveys of the 
waterfront area from July to September 2008 (Tannenbaum et al., 2009) 
and November to May 2010 (Tannenbaum et al., 2011), as described 
previously. Harbor seals were sighted during every survey and were 
found in all marine habitats including nearshore waters and deeper 
water, and hauled out on certain manmade objects, such as the pontoons 
of the floating security barrier. During most of the year, all age and 
sex classes could occur in the project area throughout the period of 
construction activity. As there are no known regular pupping sites in 
the vicinity of the project area, harbor seal neonates are not expected 
to be present during pile removal. However, the first documented birth 
of a harbor seal at NBKB occurred in August 2011 at Carderock Pier 
(several miles south of the project site), so the presence of neonates 
is possible, if unlikely. Otherwise, during most of the year, all age 
and sex classes could occur in the project area throughout the period 
of construction activity. 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. 
The main haul-out locations for harbor seals in Hood Canal are located 
on river delta and tidal exposed areas at various river mouths, with 
the closest haul-out area to the project area being 10 mi (16 km) 
southwest of NBKB (London, 2006). Please see Figure 4-1 of the Navy's 
application for a map of haul-out locations in relation to the project 
area.
    Jeffries et al. (2003) conducted aerial surveys of the harbor seal 
population in Hood Canal in 1999 for the Washington Department of Fish 
and Wildlife and reported 711 harbor seals hauled out. The authors 
adjusted this abundance with a correction factor of 1.53 to account for 
seals in the water, which

[[Page 25433]]

were not counted, and estimated that there were 1,088 harbor seals in 
Hood Canal. The correction factor (1.53) was based on the proportion of 
time seals spend on land versus in the water over the course of a day, 
and was derived by dividing one by the percentage of time harbor seals 
spent on land. These data came from tags (VHF transmitters) applied to 
harbor seals at six areas (Grays Harbor, Tillamook Bay, Umpqua River, 
Gertrude Island, Protection/Smith Islands, and Boundary Bay, BC) within 
two different harbor seal stocks (the coastal stock and the inland 
waters of WA stock) over four survey years. The Hood Canal population 
is part of the inland waters stock, and while not specifically sampled, 
Jeffries et al. (2003) found the VHF data to be broadly applicable to 
the entire stock. The tagging research in 1991 and 1992 conducted by 
Huber et al. (2001) and Jeffries et al. (2003) used the same methods 
for the 1999 and 2000 survey years. These surveys indicated that 
approximately 35 percent of harbor seals are in the water versus hauled 
out on a daily basis (Huber et al., 2001; Jeffries et al., 2003). 
Exposures were calculated using a density derived from the number of 
harbor seals that are present in the water at any one time (35 percent 
of 1,088, or approximately 381 individuals), divided by the area of the 
Hood Canal (291 km \2\ [112 mi \2\]) and the formula presented 
previously.
    NMFS recognizes that over the course of the day, while the 
proportion of animals in the water may not vary significantly, 
different individuals may enter and exit the water. However, fine-scale 
data on harbor seal movements within the project area on time durations 
of less than a day are not available. Previous monitoring experience 
from Navy actions conducted from July-October 2011 in the same project 
area has indicated that this density provides an appropriate estimate 
of potential exposures. Data from those monitoring efforts are 
currently in post-processing and are not available in report form at 
this time. However, the density of harbor seals calculated in this 
manner (1.3 animals/km \2\) is corroborated by results of the Navy's 
vessel-based marine mammal surveys at NBKB in 2008 and 2009-10, in 
which an average of five individual harbor seals per survey was 
observed in the 3.9 km \2\ survey area (density = 1.3 animals/km \2\) 
(Tannenbaum et al., 2009, 2011). Table 8 depicts the number of 
estimated behavioral harassments.

Humpback Whales

    One humpback whale has recently been documented in Hood Canal. This 
individual was originally sighted on January 27, 2012 and, while 
potentially still present, was last reported on February 23, 2012. 
Although known to be historically abundant in the inland waters of 
Washington, no other confirmed documentation of humpback whales in Hood 
Canal is available. Their presence has likely not occurred in several 
decades, with the last known reports being anecdotal accounts of three 
humpback sightings from 1972-82. Although it cannot be confirmed that 
this individual has departed the Hood Canal, with the absence of 
sighting records since February 23 (following regular sightings between 
January 27-February 23) and the lack of any historical regular 
occurrence in the Hood Canal it is likely that this individual has 
departed and that no humpback whales would be present in the proposed 
action area. In addition, the proposed action is estimated to occur for 
only 15 days, with short pile removal durations per day. As described 
before, cetaceans are not known from within the WRA and it's virtually 
impossible that an animal as large as a humpback whale could occur 
within the WRA; therefore, sound from pneumatic chipping, which is not 
expected to extend beyond the floating security barrier, would not have 
the potential to affect humpback whales. NMFS believes that the 
possibility for incidental take of humpback whales is discountable. In 
addition to the preceding rationale given in support of this belief, a 
density was derived from the available information: One humpback whale 
ranging through the Hood Canal (291 km\2\), or 0.003 animals/km\2\. 
Using this density and the formula given previously, no takes are 
predicted.

Killer Whales

    Transient killer whales are uncommon visitors to Hood Canal. 
Transients may be present in the Hood Canal anytime during the year and 
traverse as far as the project site. Resident killer whales have not 
been observed in Hood Canal, but transient pods (six to eleven 
individuals per event) were observed in Hood Canal for lengthy periods 
of time (59-172 days) in 2003 (January-March) and 2005 (February-June), 
feeding on harbor seals (London, 2006).
    These whales used the entire expanse of Hood Canal for feeding. 
Subsequent aerial surveys suggest that there has not been a sharp 
decline in the local seal population from these sustained feeding 
events (London, 2006). Based on this data, the density for transient 
killer whales in the Hood Canal for January to June is 0.038/km\2\ 
(eleven individuals divided by the area of the Hood Canal [291 km\2\]). 
Table 8 depicts the number of estimated behavioral harassments.

Dall's Porpoise

    Dall's porpoises may be present in the Hood Canal year-round and 
could occur as far south as the project site. Their use of inland 
Washington waters, however, is mostly limited to the Strait of Juan de 
Fuca. The Navy conducted vessel-based surveys of the waterfront area in 
2008-10 (Tannenbaum et al., 2009, 2011). During one of the surveys a 
Dall's porpoise was sighted in August in the deeper waters off Carlson 
Spit.
    In the absence of an abundance estimate for the entire Hood Canal, 
a density was derived from the waterfront survey by the number of 
individuals seen divided by total number of kilometers of survey effort 
(18 surveys with approximately 3.9 km\2\ [1.5 mi\2\] of effort each), 
assuming strip transect surveys. In the absence of any other survey 
data for the Hood Canal, this density is assumed to be throughout the 
project area. Exposures were calculated using the formula presented 
previously. Table 8 depicts the number of estimated behavioral 
harassments.

Harbor Porpoise

    Harbor porpoises may be present in the Hood Canal year-round; their 
presence had previously been considered rare. During waterfront surveys 
of NBKB nearshore waters from 2008-10 only one harbor porpoise had been 
seen in 18 surveys of 3.9 km\2\ each. However, during monitoring of 
recent Navy actions at NBKB, several sightings indicated that their 
presence may be more frequent in deeper waters of Hood Canal than had 
been believed on the basis of existing survey data and anecdotal 
evidence. Subsequently, the Navy conducted dedicated vessel-based line 
transect surveys on days when no construction activity occurred (due to 
security, weather, etc.), described previously in this document, with 
regular observations of harbor porpoise groups. Sightings in the deeper 
waters of Hood Canal ranged up to eleven individuals, with an average 
of approximately six animals sighted per survey day (Navy, in prep.).
    Sightings of harbor porpoises during these surveys were used to 
generate a density for Hood Canal. Based on guidance from other line 
transect surveys conducted for harbor porpoises using similar 
monitoring parameters (e.g., boat speed, number of observers) (Barlow, 
1988; Calambokidis et al., 1993; Caretta et al., 2001), the Navy 
determined the effective strip width for the surveys to be 1 km, or a

[[Page 25434]]

perpendicular distance of 500 m from the transect to the left or right 
of the vessel. The effective strip width was set at the distance at 
which the detection probability for harbor porpoises was equivalent to 
one, which assumes that all individuals on a transect are detected. 
Only sightings occurring within the effective strip width were used in 
the density calculation. By multiplying the trackline length of the 
surveys by the effective strip width, the total area surveyed during 
the surveys was 259.01 km\2\. Thirty-five individual harbor porpoises 
were sighted within this area, resulting in a density of 0.135 animals 
per km\2\. To account for availability bias, or the animals which are 
unavailable to be detected because they are submerged, the Navy 
utilized a g(0) value of 0.54, derived from other similar line transect 
surveys (Barlow, 1988; Calambokidis et al., 1993; Carretta et al., 
2001). This resulted in a density of 0.250 harbor porpoises per km\2\. 
For comparison, 274.27 km\2\ of trackline survey effort in nearby Dabob 
Bay produced a corrected density estimate of 0.203 harbor porpoises per 
km\2\. Exposures were calculated using the formula described 
previously. Table 8 depicts the number of estimated behavioral 
harassments.
    Potential takes could occur if individuals of these species move 
through the area on foraging trips when pile removal is occurring. 
Individuals that are taken could exhibit behavioral changes such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging. Most likely, individuals may move away from the sound source 
and be temporarily displaced from the areas of pile removal. Potential 
takes by disturbance would likely have a negligible short-term effect 
on individuals and not result in population-level impacts.

                         Table 8--Number of Potential Incidental Takes of Marine Mammals Within Various Acoustic Threshold Zones
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                            Underwater                       Airborne
                                                                         ----------------------------------------------------------------
                                                                                            Disturbance     Disturbance                   Total proposed
                         Species                             Density/                       threshold--     threshold--                     authorized
                                                             abundance        Injury         vibratory       pneumatic      Disturbance        takes
                                                                           threshold \1\   removal (120    chipping (120   threshold \2\
                                                                                                dB)             dB)
--------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lion.....................................      \3\ 26.2                 0           * 390            * 32               0             422
Steller sea lion........................................       \3\ 1.2                 0            * 60            * 32               0              92
Harbor seal.............................................           1.31                0             705              32               0             737
Humpback whale..........................................           0.003               0               0               0             N/A               0
Killer whale............................................           0.038               0              15               0             N/A              15
Dall's porpoise.........................................           0.014               0              15               0             N/A              15
Harbor porpoise.........................................           0.250               0             135               0             N/A             135
                                                         -----------------------------------------------------------------------------------------------
    Total...............................................  ..............               0           1,320              96               0           1,416
--------------------------------------------------------------------------------------------------------------------------------------------------------
* See preceding species-specific discussions for description of take estimate.
\1\ Acoustic injury threshold is 190 dB for pinnipeds and 180 dB for cetaceans. No activity would produce source levels equal to 190 dB, while only
  vibratory removal would produce a source level of 180 dB.
\2\ Acoustic disturbance threshold is 100 dB for sea lions and 90 dB for harbor seals. NMFS does not believe that pinnipeds would be available for
  airborne acoustic harassment because they are known to haul-out only at locations well outside the zone in which airborne acoustic harassment could
  occur; nevertheless, calculations predict that no incidental take would occur as a result of airborne sound.
\3\ Figures presented are abundance numbers, not density, and are calculated as the average of average daily maximum numbers per month. Abundance
  numbers are rounded to the nearest whole number for take estimation.

Negligible Impact and Small Numbers Analysis and Preliminary 
Determination

    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, 
NMFS considers 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.
    Pile removal activities associated with the wharf rehabilitation 
project, as outlined previously, have the potential to disturb or 
displace marine mammals. Specifically, the proposed activities may 
result in take, in the form of Level B harassment (behavioral 
disturbance) only, from underwater sounds generated through pile 
removal. No mortality, serious injury, or Level A harassment is 
anticipated given the nature of the activity (i.e., non-pulsed sound 
with low source levels) and measures designed to minimize the 
possibility of injury to marine mammals, while Level B harassment would 
be reduced to the level of least practicable adverse impact for the 
same reasons. Specifically, these removal methods would produce lower 
source levels than would pile installation with a vibratory hammer, 
which does not have significant potential to cause injury to marine 
mammals due to its sound source characteristics and relatively low 
source levels. Pile removal would either not start or be halted if 
marine mammals approach the shutdown zone (described previously in this 
document). The pile removal activities analyzed here carry 
significantly less risk of impact to marine mammals than did other 
construction activities analyzed and monitored within the Hood Canal, 
including two recent projects conducted by the Navy at the same 
location (test pile project and the first year of EHW-1 pile 
replacement work) as well as work conducted in 2005 for the Hood Canal 
Bridge (SR-104) by the Washington Department of Transportation. These 
activities have taken place with no reported injuries or mortality to 
marine mammals.
    The proposed numbers of authorized take for marine mammals would be 
considered small relative to the relevant stocks or populations even if 
each estimated taking occurred to a new individual--an extremely 
unlikely scenario. The proposed numbers of authorized take represent 5 
percent of the relevant stock for harbor seals, 4.2

[[Page 25435]]

percent for transient killer whales, and 1.3 percent for harbor 
porpoises; the proposed numbers are less than 1 percent for the 
remaining species. However, even these low numbers represent potential 
instances of take, not the number of individuals taken. That is, it is 
likely that a relatively small subset of Hood Canal harbor seals, which 
is itself a small subset of the regional stock, would be harassed by 
project activities.
    For example, while the available information and formula estimate 
that as many as 737 exposures of harbor seals to stimuli constituting 
Level B harassment could occur, that number represents some portion of 
the approximately 1,088 harbor seals resident in Hood Canal 
(approximately 7 percent of the regional stock) that could potentially 
be exposed to sound produced by pile removal activities on multiple 
days during the project. No rookeries are present in the project area, 
there are no haul-outs other than those provided opportunistically by 
man-made objects, and the project area is not known to provide foraging 
habitat of any special importance. 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 Hood Canal harbor seals, and thus would not 
result in any adverse impact to the stock as a whole.
    NMFS has preliminarily determined that the impact of the previously 
described wharf rehabilitation project may result, at worst, in a 
temporary modification in behavior (Level B harassment) of small 
numbers of marine mammals. No injury, serious injury, or mortality is 
anticipated as a result of the specified activity, and none is proposed 
to be authorized. Additionally, animals in the area are not expected to 
incur hearing impairment (i.e., TTS or PTS) or non-auditory 
physiological effects. For pinnipeds, the absence of any major 
rookeries and only a few isolated and opportunistic haul-out areas near 
or adjacent to the project site means that potential takes by 
disturbance would have an insignificant short-term effect on 
individuals and would not result in population-level impacts. 
Similarly, for cetacean species the absence of any known regular 
occurrence adjacent to the project site means that potential takes by 
disturbance would have an insignificant short-term effect on 
individuals and would not result in population-level impacts. Due to 
the nature, degree, and context of behavioral harassment anticipated, 
the activity is not expected to impact rates of recruitment or 
survival.
    While the number of marine mammals potentially incidentally 
harassed would depend on the distribution and abundance of marine 
mammals in the vicinity of the survey activity, the number of potential 
harassment takings is estimated to be small relative to regional stock 
or population number, and has been mitigated to the lowest level 
practicable through incorporation of the proposed mitigation and 
monitoring measures mentioned previously in this document. This 
activity is expected to result in a negligible impact on the affected 
species or stocks. The eastern DPS of the Steller sea lion is listed as 
threatened under the ESA; no other species for which take authorization 
is requested are either ESA-listed or considered depleted under the 
MMPA.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, NMFS preliminarily finds that the proposed wharf construction 
project would result in the incidental take of small numbers of marine 
mammals, by Level B harassment only, and that the total taking from the 
activity would have a negligible impact on the affected species or 
stocks.

Impact on Availability of Affected Species or Stock for Taking for 
Subsistence Uses

    No tribal subsistence hunts are held in the vicinity of the project 
area; thus, temporary behavioral impacts to individual animals would 
not affect any subsistence activity. Further, no population or stock 
level impacts to marine mammals are anticipated or authorized. As a 
result, no impacts to the availability of the species or stock to the 
Pacific Northwest treaty tribes are expected as a result of the 
proposed activities. Therefore, no relevant subsistence uses of marine 
mammals are implicated by this action.

Endangered Species Act (ESA)

    There are two ESA-listed marine mammal species with known 
occurrence in the project area: The eastern DPS of the Steller sea 
lion, listed as threatened, and the humpback whale, listed as 
endangered. Because of the potential presence of these species, the 
Navy has requested a formal consultation with the NMFS Northwest 
Regional Office under section 7 of the ESA. NMFS' Office of Protected 
Resources has also initiated formal consultation on its authorization 
of incidental take of Steller sea lions. These consultations are in 
progress. These species do not have critical habitat in the action 
area.

National Environmental Policy Act (NEPA)

    In compliance with the National Environmental Policy Act of 1969 
(42 U.S.C. 4321 et seq.), as implemented by the regulations published 
by the Council on Environmental Quality (40 CFR parts 1500-1508), and 
NOAA Administrative Order 216-6, the Navy prepared an Environmental 
Assessment (EA) to consider the direct, indirect and cumulative effects 
to the human environment resulting from the pile replacement project. 
NMFS adopted that EA in order to assess the impacts to the human 
environment of issuance of an IHA to the Navy. NMFS signed a Finding of 
No Significant Impact (FONSI) on May 17, 2011. On the basis of new 
information related to the occurrence of marine mammals in the Hood 
Canal, the Navy is preparing a supplement to that EA. NMFS will review 
that document and, if appropriate, issue a new FONSI.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
authorize the take of marine mammals incidental to the Navy's wharf 
rehabilitation project, provided the previously mentioned mitigation, 
monitoring, and reporting requirements are incorporated.

    Dated: April 24, 2012.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2012-10370 Filed 4-27-12; 8:45 am]
BILLING CODE 3510-22-P