Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Wharf Construction Project, 42279-42297 [2012-17488]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 77, Number 138 (Wednesday, July 18, 2012)]
[Notices]
[Pages 42279-42297]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-17488]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA830


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to a Wharf Construction Project

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

ACTION: Notice; issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that we have issued an incidental harassment authorization (IHA) to the 
U.S. Navy (Navy) to incidentally harass, by Level B harassment only, 
six species of marine mammals during construction activities associated 
with a wharf construction project in Hood Canal, Washington.

DATES: This authorization is effective from July 16, 2012, through 
February 15, 2013.

ADDRESSES: A copy of the IHA and related documents are available by 
writing to Michael Payne, Chief, Permits and Conservation Division, 
Office of Protected Resources, National Marine Fisheries Service, 1315 
East-West Highway, Silver Spring, MD 20910.

[[Page 42280]]

    A copy of the application, including references used in this 
document, may be obtained by visiting the Internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm. For those members of the 
public unable to view these documents on the Internet, a copy may be 
obtained by writing to the address specified above or telephoning the 
contact listed below (see FOR FURTHER INFORMATION CONTACT). A 
memorandum describing our adoption of the Navy's Environmental Impact 
Statement (2011) and our associated Record of Decision, prepared 
pursuant to the National Environmental Policy Act, are also available 
at the same site. Documents cited in this notice may also be viewed, by 
appointment, during regular business hours, at the aforementioned 
address.

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

    We received an application on May 25, 2011 from the Navy for the 
taking of marine mammals incidental to pile driving in association with 
a wharf construction project in the Hood Canal at Naval Base Kitsap in 
Bangor, WA (NBKB). The Navy submitted a revised version of the 
application on August 11, 2011, and, responsive to discussions with us 
as well as new information about species in the area, submitted a final 
version deemed adequate and complete on November 3, 2011. The Navy 
submitted a final updated addendum to the IHA request on December 16, 
2011.The wharf construction project is proposed to occur over multiple 
years; however, this IHA would cover only the initial year of in-water 
work associated with the project. Pile driving activities would occur 
only within an approved in-water work window from July 16, 2012, 
through February 15, 2013. Six 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), and harbor porpoises (Phocoena 
phocoena). In addition, a single humpback whale (Megaptera 
novaeangliae) was observed in the Hood Canal during January and 
February, 2012; please note that these sightings occurred after the 
notice of proposed authorization for this project was published in the 
Federal Register. Therefore, descriptions of humpback whale occurrence 
in Puget Sound are included here.
    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). Although 
known to be historically abundant in the inland waters of Washington, 
no other confirmed documentation of humpback whales in Hood Canal is 
available. 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.
    Under the proposed action--which includes only the portion of the 
project that would be completed under this proposed 1-year IHA--a 
maximum of 195 pile driving days would occur. All piles would be driven 
with a vibratory hammer for their initial embedment depths, while 
select piles would be impact driven for their final 10-15 ft (3-4.6 m) 
for proofing, as necessary. Proofing involves striking a driven pile 
with an impact hammer to verify that it provides the required load-
bearing capacity, as indicated by the number of hammer blows per foot 
of pile advancement. Sound attenuation measures (i.e., bubble curtain) 
would be used during all impact hammer operations.
    For pile driving activities, the Navy used our current acoustic 
thresholds, outlined later in this document, for assessing impacts. 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 30- to 66-in diameter steel pile driving events to estimate 
potential marine mammal exposures. Predicted exposures are outlined 
later in this document. The calculations predict that no Level A 
harassments would occur associated with pile driving or construction 
activities, and that as many as 18,225 Level B harassments may occur 
during the wharf construction project from sound produced by pile 
driving activity.

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 2-4 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's construction of the EHW-2 facility at NBKB is 
planned to support future program requirements for TRIDENT submarines 
berthed at NBKB. The Navy states that construction of EHW-2 is

[[Page 42281]]

necessary because the existing EHW alone will not be able to support 
future TRIDENT program requirements. Under the MMPA, activities 
associated with the wharf construction project, including vibratory and 
impact pile driving operations and vibratory removal of falsework 
piles, have the potential to cause harassment of marine mammals within 
the waterways adjacent to NBKB. All in-water construction activities 
within the Hood 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, testing, evaluation, and operational support for the 
TRIDENT Fleet Ballistic Missile program. Development of necessary 
facilities for handling of explosive materials is part of these duties. 
The EHW-2 will consist of two components: (1) The wharf proper (or 
Operations Area), including the warping wharf; and (2) two access 
trestles. Please see Figures 1-1 and 1-2 of the Navy's application for 
conceptual and schematic representations of the EHW-2. Details 
regarding construction plans for the wharf were described in our 
Federal Register notice of proposed authorization (76 FR 79410; 
December 21, 2011; hereafter, the FR notice); please see that document 
or the Navy's application for construction details.
    For the entire project, a total of up to 1,250 permanent piles 
ranging in size from 24- to 48-in diameter will be driven in-water to 
construct the wharf, with up to three vibratory rigs and one impact 
driving rig operating simultaneously. Construction will also require 
temporary installation of up to 150 falsework piles used as an aid to 
guide permanent piles to their proper locations. Falsework piles, which 
are removed upon installation of the permanent piles, will likely be 
driven and removed using a vibratory driver. It has not been determined 
exactly what parts or how much of the project will be completed during 
the first year; however, a maximum of 195 days of pile driving will 
occur. The analysis contained herein is based upon the maximum of 195 
pile driving days, rather than any specific number of piles driven, 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. Table 1 summarizes the number and nature 
of piles required for the entire project, rather than what subset of 
piles may be expected to be driven during the first year of 
construction.

        Table 1--Summary of Piles Required for Wharf Construction
                               [In total]
------------------------------------------------------------------------
           Feature                              Quantity
------------------------------------------------------------------------
Total number of permanent in-  Up to 1,250.
 water piles.
Size and number of main wharf  24-in: 140.
 piles.
                               36-in: 157.
                               48-in: 263.
Size and number of warping     24-in: 80.
 wharf piles.
                               36-in: 190.
Size and number of lightning   24-in: 40.
 tower piles.
                               36-in: 90.
Size and number of trestle     24-in: 57.
 piles.
                               36-in: 233.
Falsework piles..............  Up to 150, 18- to 24-in.
Maximum pile driving duration  195 days (under 1-year IHA).
------------------------------------------------------------------------

    Pile installation will employ vibratory pile drivers to the 
greatest extent possible, and the Navy anticipates that most piles will 
be able to be vibratory driven to within several feet of the required 
depth. Pile drivability is, to a large degree, a function of soil 
conditions and the type of pile hammer. Recent experience at two other 
construction locations along the NBKB waterfront indicates that most 
piles should be able to be driven with a vibratory hammer to proper 
embedment depth. However, difficulties during pile driving may be 
encountered as a result of obstructions that may exist throughout the 
project area. Such obstructions may consist of rocks or boulders within 
the glacially overridden soils. If difficult driving conditions occur, 
increased usage of an impact hammer will be required. The Navy 
estimates that up to five piles may be proofed in a day, requiring a 
maximum total of 1,000 strikes from the impact hammer. Under a worst-
case scenario (i.e., difficult subsurface driving conditions 
encountered), as many as three piles might require driving with an 
impact hammer to their full embedment depth. With proofing of two 
additional piles, this scenario would result in as many as 6,400 impact 
pile strikes in a day. Please see the FR notice (76 FR 79410; December 
21, 2011) for more detail.
    Impact pile driving during the first half of the in-water work 
window (July 16 to September 15) would only occur between 2 hours after 
sunrise and 2 hours before sunset to protect breeding marbled murrelets 
(Brachyramphus marmoratus; an ESA-listed bird under the jurisdiction of 
the U.S. Fish and Wildlife Service [USFWS]). Between September 16 and 
February 15, construction activities occurring in the water would occur 
during daylight hours (sunrise to sunset). Other construction (not in-
water) may occur between 7 a.m. and 10 p.m., year-round.

Description of Sound Sources and Distances to Thresholds

    An in-depth description of sound sources in general was provided in 
the FR notice (76 FR 79410; December 21, 2011). Significant sound-
producing in-water construction activities associated with the project 
include impact and vibratory pile driving and vibratory pile removal.
    Since 1997, we have used generic sound exposure thresholds as 
guidelines to estimate when harassment may occur. Current practice 
regarding exposure of marine mammals to sound defines thresholds as 
follows: cetaceans and pinnipeds exposed to sound levels of 180 and 190 
dB root mean square (rms; note that all underwater sound levels in this 
document are referenced to a pressure of 1 [mu]Pa) or above,

[[Page 42282]]

respectively, are considered to have been taken by Level A (i.e., 
injurious) harassment, while behavioral harassment (Level B) is 
considered to have occurred when marine mammals are exposed to sounds 
at or above 120 dB rms for continuous sound (such as will be produced 
by vibratory pile driving) and 160 dB rms for pulsed sound (produced by 
impact pile driving), but below injurious thresholds. For airborne 
sound, pinniped disturbance from haul-outs has been documented at 100 
dB (unweighted) for pinnipeds in general, and at 90 dB (unweighted) for 
harbor seals (note that all airborne sound levels in this document are 
referenced to a pressure of 20 [micro]Pa).
    Sound levels can be greatly reduced during impact pile driving 
using sound attenuation devices. The Navy is required to use sound 
attenuation devices for all impact pile driving, and has elected to use 
bubble curtains. Bubble curtains work by creating a column of air 
bubbles rising around a pile from the substrate to the water surface. 
The air bubbles absorb and scatter sound waves emanating from the pile, 
thereby reducing the sound energy. A confined bubble curtain contains 
the air bubbles within a flexible or rigid sleeve made from plastic, 
cloth, or pipe. Confined bubble curtains generally offer higher 
attenuation levels than unconfined curtains because they may physically 
block sound waves and they prevent air bubbles from migrating away from 
the pile.
    The literature presents a wide array of observed attenuation 
results for bubble curtains (e.g., WSF, 2009; WSDOT, 2008; USFWS, 2009; 
Caltrans, 2009). The variability in attenuation levels is due to 
variation in design, as well as differences in site conditions and 
difficulty in properly installing and operating in-water attenuation 
devices. As a general rule, reductions of greater than 10 dB cannot be 
reliably predicted (Caltrans, 2009).

Distance to Sound Thresholds

    Pile driving generates underwater noise that can potentially result 
in disturbance to marine mammals in the project area. Please see the FR 
notice (76 FR 79410; December 21, 2011) for a detailed description of 
the calculations and information used to estimate distances to relevant 
threshold levels. Transmission loss, or the decrease in acoustic 
intensity as an acoustic pressure wave propagates out from a source, 
was estimated as so-called ``practical spreading loss''. 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 the model used here, the sound pressure 
level (SPL) at some distance away from the source (e.g., driven pile) 
is governed by a measured source level, minus the transmission loss of 
the energy as it dissipates with distance.
    The intensity of pile driving sounds is greatly influenced by 
factors such as the type of piles, hammers, and the physical 
environment in which the activity takes place. A large quantity of 
literature regarding SPLs recorded from pile driving projects is 
available for consideration. In order to determine reasonable SPLs and 
their associated affects on marine mammals that are likely to result 
from pile driving at NBKB, studies with similar properties to the 
proposed action were evaluated. Sound levels associated with vibratory 
pile removal are assumed to be the same as those during vibratory 
installation (Caltrans, 2007)--which is likely a conservative 
assumption--and have been taken into consideration in the modeling 
analysis. Overall, studies which met the following parameters were 
considered: (1) Pile size and materials: Steel pipe piles (30-72 in 
diameter); (2) Hammer machinery: Vibratory and impact hammer; and (3) 
Physical environment: shallow depth (less than 100 ft [30 m]).
    Representative data for pile driving SPLs recorded from similar 
construction activities in recent years were presented in the FR notice 
(76 FR 79410; December 21, 2011). As described previously in this 
document, sound attenuation measures, including bubble curtains, can be 
employed during impact pile driving to reduce the high source 
pressures. For the wharf construction project, the Navy intends to 
employ sound reduction techniques during impact pile driving, including 
the use of sound attenuation systems (e.g., bubble curtain). The 
calculations of the distances to the marine mammal sound thresholds 
were calculated for impact installation with the assumption of a 10 dB 
reduction in source levels from the use of sound attenuation devices, 
and the Navy used the mitigated distances for impact pile driving for 
all analysis in their application. The Navy will require the 
contractors to employ a bubble curtain with proven performance of 10 dB 
attenuation and will require measures to ensure that the system is 
deployed properly.
    All calculated distances to and the total area encompassed by the 
marine mammal sound thresholds are provided in Table 2. The Navy used 
source values (at 10 m) of 185 dB for impact driving (the mean SPL of 
the representative values, less 10 dB of sound attenuation from use of 
a bubble curtain) and 180 dB for vibratory driving (the worst-case 
value from the representative data). Use of the mean SPL of values for 
impact driving was considered appropriate because it matched values 
from projects where larger-size pile was used and, in addition, matched 
the value obtained from the Carderock project, which was located at the 
NBKB waterfront and involved similar pile materials, water depth, and 
bottom type. Use of the maximum value for vibratory driving was deemed 
appropriate because no data were available for larger size piles.
    Under likely construction scenarios, up to three vibratory drivers 
would operate simultaneously with one impact driver. Although radial 
distance and area associated with the zone ensonified to 160 dB rms 
(the behavioral harassment threshold for pulsed sounds, such as those 
produced by impact driving) are presented in Table 2 for reference, 
this zone would be subsumed by the 120 dB rms zone produced by 
vibratory driving. Although animals may react differently to pulsed 
sound above 160 dB or non-pulsed sound above 120 dB, there is no 
practical distinction to be made as regards estimation of incidental 
take under the multi-rig operating scenario. Animals would not be 
considered to be taken multiple times if exposed to different types of 
sound above the thresholds for behavioral harassment. Thus, behavioral 
harassment of marine mammals associated with impact driving is not 
considered further here.
    The use of multiple similar vibratory rigs that are operating 
together closely in space and time would not result in larger 120 dB or 
180/190 dB isopleths for the hypothetical situation presented here, in 
which a single vibratory driver produces SPLs of 180 dB rms at 10 m 
(based upon acoustic monitoring, discussed later, these levels are 
likely to be lower). For the 120 dB isopleths, sound fields produced 
would already be truncated by land in the Hood Canal, which has a 
maximum line-of-sight distance from pile driving locations of 13.8 km. 
That is, no increase in the size of the actual 120 dB isopleths would 
occur with multiple vibratory rigs operating simultaneously, because 
those isopleths as produced by a single rig are already truncated by 
land (according to predictions from proxy source levels and practical 
spreading loss--actual isopleth distances are likely to be smaller as 
shown from monitoring results). If three similar vibratory pile drivers 
operating simultaneously each

[[Page 42283]]

had overlapping 180 dB isopleths, they would produce a combined SPL of 
approximately 185 dB due to the properties of decibel addition. 
However, since these drivers will actually be separated in space such 
that no overlap in 180 dB isopleths would occur, the operation of 
multiple rigs will not result in any changes to injury zones.

  Table 2--Calculated Distance(s) to and Area Encompassed by Underwater
         Marine Mammal Sound Thresholds During Pile Installation
------------------------------------------------------------------------
          Threshold                 Distance            Area, km \2\
------------------------------------------------------------------------
Impact driving, pinniped      4.9 m...............  <0.001
 injury (190 dB).
Impact driving, cetacean      22 m................  0.002
 injury (180 dB).
Impact driving, disturbance   724 m...............  1.65
 (160 dB) \2\.
Vibratory driving, pinniped   2.1 m...............  <0.001
 injury (190 dB).
Vibratory driving, cetacean   10 m................  <0.001
 injury (180 dB).
Vibratory driving,            13,800 m \3\........  41.4 (15.98)
 disturbance (120 dB).
------------------------------------------------------------------------
\1\ SPLs used for calculations were: 185 dB for impact and 180 dB for
  vibratory driving.
\2\ Area of 160-dB zone presented for reference. Estimated incidental
  take calculated on basis of larger 120-dB zone.
\3\ Hood Canal average width at site is 2.4 km (1.5 mi), and is fetch
  limited from N to S at 20.3 km (12.6 mi). Calculated range (over 222
  km) is greater than actual sound propagation through Hood Canal due to
  intervening land masses. 13.8 km (8.6 mi) is the greatest line-of-
  sight distance from pile driving locations unimpeded by land masses,
  which would block further propagation of sound.

    Hood Canal does not represent open water, or free field, 
conditions. Therefore, sounds would attenuate as they encounter land 
masses or bends in the canal. As a result, the calculated distance and 
areas of impact for the 120 dB threshold cannot actually be attained at 
the project area. See Figure 6-1 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 driving.
    Pile driving 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. A spherical spreading loss model (i.e., 
6 dB reduction in sound level for each doubling of distance from the 
source), in which there is a perfectly unobstructed (free-field) 
environment not limited by depth or water surface, is appropriate for 
use with airborne sound and was used to estimate the distance to the 
airborne thresholds.
    As was discussed for underwater sound from pile driving, the 
intensity of pile driving sounds is greatly influenced by factors such 
as the type of piles, hammers, and the physical environment in which 
the activity takes place. In order to determine reasonable airborne 
SPLs and their associated effects on marine mammals that are likely to 
result from pile driving at NBKB, studies with similar properties to 
the Navy's project, as described previously, were evaluated.
    Based on in-situ recordings from similar construction activities, 
the maximum airborne sound levels that would result from impact and 
vibratory pile driving are estimated to be 97 dB rms re 20 [mu]Pa at 
160 m and 97 dB rms re 20 [mu]Pa at 13 m, respectively (Blackwell et 
al., 2004; Laughlin, 2010b). The Navy has analyzed the combined sound 
field produced under the multi-rig scenario and calculated the radial 
distances to the 90 and 100 dB airborne thresholds as 361 m and 114 m, 
respectively, equating to areas of 0.41 km\2\ and 0.04 km\2\, 
respectively. These distances are predicted to be significantly less 
for the vibratory driver alone, approximately 28 m (92 ft) and 9 m (30 
ft), respectively.
    All airborne distances are less than those calculated for 
underwater sound thresholds. Protective measures will be in place out 
to the distances calculated for the underwater thresholds, and the 
distances for the airborne thresholds will be covered fully by 
mitigation and monitoring measures in place for underwater sound 
thresholds. Construction sound associated with the project is not 
predicted to extend beyond the buffer zone for underwater sound that 
will be established to protect pinnipeds. No haul-outs or rookeries are 
located within the airborne harassment radii. See Figure 6-2 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 driving.

Acoustic Monitoring

    In 2011, the Navy conducted acoustic monitoring as required by IHAs 
for repair work conducted at the existing EHW (EHW-1) (76 FR 30130; May 
24, 2011) and for a test pile project (76 FR 25408; June 30, 2011) 
conducted in order to obtain geotechnical data in advance of the EHW-2 
project. The two projects together involved impact driving of 24- to 
48-in piles, vibratory installation of 16- to 48-in piles, and 
vibratory removal of 12- to 48-in piles. All piles were steel pipe 
piles. Primary objectives for the acoustic monitoring were to 
characterize underwater and airborne source levels for each pile size 
and hammer type and to verify distances to relevant threshold levels by 
characterizing site-specific transmission loss. Secondary objectives 
included testing the effective attenuation performance for use of a 
bubble curtain and investigation of SPLs produced during soft starts. 
Select results are reproduced here; the interested reader may find the 
entire reports posted at https://www.nmfs.noaa.gov/pr/permits/incidental.htm.

                                            Table 3--Acoustic Monitoring Results From 2011 Activities at NBKB
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Underwater           Airborne               Distances to threshold (m) \7\
  Pile size (in)         Hammer type \1\           n \2\     -------------------------------------------------------------------------------------------
                                                              RL \3\  SD \4\  TL \5\  RL \6\    SD       190       180      160     120     100     90
--------------------------------------------------------------------------------------------------------------------------------------------------------
24................  Impact..................           1 (2)     174     0.7    13.2      89     n/a       <10       <10     108     n/a      47     150
36................  Impact..................       10 (17)/9     182     5.7    16.4      92     2.3       <10        28     398     n/a      48     150
48................  Impact..................           4 (8)     187     4.4    13.4      91     2.1    <10/15        40   1,180     n/a      34     108
24................  Vibratory...............         4 (7)/2     164     5.0    17.4      91     1.4  ........  ........     n/a   2,635      14      45
36................  Vibratory (I)...........      23 (42)/30     162     4.3    15.1      93     2.9  ........  ........     n/a   6,082      20      64
36................  Vibratory (R)...........         21 (36)     157     4.5

[[Page 42284]]

 
48................  Vibratory (I)...........       7 (14)/11     163     5.1    16.3      94     3.2  ........  ........     n/a   5,046      24      75
48................  Vibratory (R)...........          8 (15)     155     4.5                          ........  ........
12................  Vibratory (R)...........       6 (4) \8\     160     2.4    16.5  ......  ......  ........  ........     n/a   5,375      22      69
16................  Vibratory (I)...........          8 (16)     159     4.7          ......  ......  ........  ........     n/a
30................  Vibratory (I)...........         44 (87)     165     4.5          ......  ......  ........  ........     n/a              44     138
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ For vibratory hammer, I = installation and R = removal. Because of limited sample size for 24-in piles, all events were combined. All data for
  impact driving include use of bubble curtain.
\2\ n = sample size, or number of measured pile driving events. For categories where two numbers are listed, sample size was different for underwater
  and airborne measurements. For underwater, each event may have up to two measurements because two hydrophones were deployed at different depths;
  however, both hydrophones did not produce usable data for all events. For airborne events, each event represents a single measurement. Information is
  presented as follows:  underwater events measured (total  measurements; maximum would be twice the total  events)/
  airborne events measured (if different).
\3\ Received level at 10 m, presented in dB re: 1 [micro]Pa rms.
\4\ Standard deviation.
\5\ Transmission loss (log10). Mean TL calculations for vibratory driving were not separated by I/R. A single mean TL value was calculated for 12/16/30-
  in piles.
\6\ Received level at 15 m, presented in dB re: 20 [micro]Pa rms. Airborne measurements were combined for I/R events, as no difference in airborne SPLs
  would be expected. No near-source measurements were conducted for 12/16/30-in piles.
\7\ Indicated thresholds are in dB rms and correspond with those described previously under Description of Sound Sources and Distances to Thresholds.
  Combined values for mean distance to threshold were calculated for I/R events and for airborne sound. Values were calculated using interpolated TL
  values and SPL measurements at multiple distances from the source. A dash indicates that mean source level was below the relevant threshold. For
  impact driving of 48-in piles, mean distance to the 190 dB threshold was calculated as being <10 m for measurements taken at the mid-depth hydrophone
  and 15 m for measurements taken at the deep hydrophone. For all others, mean of the mean values taken at mid-depth and deep hydrophone is presented.
\8\ These six events were measured in two episodes; i.e., three separate events were measured to provide a mean in each of two episodes.

Comparison of Predictions and Measurements

    The project activities involve impact driving of 24- to 48-in steel 
piles and vibratory driving of 18- to 48-in steel piles. As shown by 
the empirical data collected during 2011 activities, the proxy value 
selected for impact driving (185 dB for impact driving with use of 
bubble curtain) is generally accurate, although SPLs from driving of 
48-in piles may be somewhat louder than expected. This may be because 
data show that realized performance from the bubble curtain may be 
somewhat less than the expected 10 dB, although testing performed in 
2011 was likely inadequate due to restrictions on the number of 
unattenuated pile strikes. No further testing will be performed because 
of similar restrictions placed on impact pile driving by the USFWS due 
to potential impacts to the marbled murrelet, an ESA-listed bird 
species. The selected proxy value for vibratory driving (180 dB) 
appears to be very conservative, with the highest SPLs recorded for 
vibratory driving being 165 dB at 10 m. Site-specific propagation loss 
appears to be generally greater than practical spreading loss, although 
the values are variable and sometimes less than practical spreading.
    Impact driving is unlikely to exceed the injury threshold for 
pinnipeds (190 dB rms) at 10 m. The mean received level at 10 m for 36-
in piles was 182 dB rms, while the mean for 48-in piles was 187 dB rms 
(with measurements from only four events). Vibratory driving is not 
likely to produce sound levels exceeding the thresholds for Level A 
harassment (i.e., 180/190 dB rms). The actual distance to the 120 dB 
rms behavioral harassment threshold is likely to be significantly 
smaller than predicted as the largest observed mean distance to 
threshold was 6,082 m for 36-in piles.
    Mean distances to airborne thresholds were smaller than those 
predicted for the multi-rig pile driving scenario. Observed distances 
for 2011 activities were smaller than the least distance to an 
available haul-out area. However, regardless of actual distance to 
threshold, it is likely that any animal exposed to airborne sound that 
may result in behavioral harassment would also be exposed to underwater 
sound above behavioral harassment thresholds, even if hauled-out during 
pile removal activity. We recognize that swimming pinnipeds may be 
exposed to airborne sound that may cause behavioral harassment if they 
raise their heads above water within the relevant zone; however, for 
purposes of take estimation these are accounted for through estimation 
of incidental take resulting from underwater sound. An animal is 
considered to be `available' for incidental take by behavioral 
harassment only once per 24-hour period, regardless of source.

Comments and Responses

    We published a notice of receipt of the Navy's application and 
proposed IHA in the Federal Register on December 21, 2011 (76 FR 
79410). NMFS received comments from the Marine Mammal Commission 
(Commission). The Commission's comments, and our responses, are 
provided here. We have determined that the mitigation measures 
described here will effect the least practicable impact on the species 
or stocks and their habitats.
    Comment 1: The Commission recommends that we require the Navy to 
measure in-air sound levels as a function of distance from the 
vibratory and impact hammers and make concurrent observations of marine 
mammal behavioral responses to in-air sound produced by pile driving 
and removal activities.
    Response: We concur with the Commission's recommendation. As 
originally proposed, the Navy will measure airborne sound levels 
associated with representative scenarios of project activities. The 
specifics of the monitoring protocol are described in detail in the 
Navy's Acoustic Monitoring Plan. The Navy will make concurrent 
observations of behavioral reactions and, if possible, relate these to 
approximate received levels of sound in order to better understand what 
levels of sound might result in behavioral harassment given the context 
present at the time of the observation. The Commission also notes that 
they would welcome the opportunity to consult with us to (1) identify 
the types of activities that have the potential to take marine mammals 
by exposure to in-air sounds, (2) determine the best scientific basis 
for identifying exposure thresholds of concern, and (3) develop 
research strategies for gathering the information needed to set more 
reliable thresholds. We look forward to working with the Commission to 
better understand these issues.
    The Commission also encourages us to simply specify that the 
authorized number of takes of pinnipeds by Level B harassment, although 
based upon the predicted footprint of underwater sound, could occur by 
exposure to underwater and/or airborne sound when

[[Page 42285]]

the animals are within an area that is ensonified to both 160 dB or 120 
dB underwater (pulsed/non-pulsed sounds, respectively) and 90/100 dB 
in-air (harbor seals and other pinnipeds, respectively), rather than 
attempting to predict these takes separately. We agree with that 
recommendation, and reflect the recommendation in our amendment of the 
take authorization. Pinnipeds, whether hauled-out or looking with head 
above water in the project vicinity, may be exposed to both airborne 
and underwater sound levels that could cause behavioral reactions 
indicating harassment. We consider exposure of the same individual to 
different stimuli that may potentially result in harassment--whether 
airborne or underwater sound or pulsed or non-pulsed sound--within the 
same 24-hour period to be a single incidence of take.
    Comment 2: The Commission recommends that we require the Navy to 
re-estimate the number of in-water and in-air takes using the overall 
density of harbor seals in Hood Canal (i.e., 3.74 animals/km\2\) or to 
use a different density estimate if monitoring data indicate one that 
is appropriate.
    Response: We disagree with the Commission's recommendation and feel 
that the density estimate used for estimating potential incidental take 
is sufficiently conservative. As described in greater detail in the FR 
notice of proposed authorization (76 FR 79410; December 21, 2011), the 
Navy's density estimate relies on work showing that, of an estimated 
1,088 seals resident to the Hood Canal, approximately 35 percent will 
be in the water at any given time (Huber et al., 2001; Jeffries et al., 
2003), producing a density estimate of 1.31 seals/km\2\. The Commission 
contends that this will result in an underestimate of take, because 
essentially all of the seals may enter the water over the matter of 
hours during which pile driving may occur in a day. It is possible that 
greater than 35 percent of seals could enter the water during the 
course of pile driving activity. However, remembering that the 
population estimate of 1,088 seals represents the entirety of Hood 
Canal (291 km\2\ vs. the 41.4 km\2\ predicted area of effect), it is 
unlikely that all of these animals would be exposed to elevated levels 
of sound from the project, even over the course of multiple days. No 
data exist regarding fine-scale harbor seal movements within the 
project area on time durations of less than a day, thus precluding an 
assessment of ingress or egress of different animals through the action 
area. As such, it is impossible, given available data, to determine 
exactly what number of individuals above 35 percent may potentially be 
exposed to underwater sound. There are no existing data that would 
indicate that the proportion of individuals entering the water within 
the predicted area of effect during pile driving would be dramatically 
larger than 35 percent; thus, the Commission's suggestion that 100 
percent of the population be used to estimate density would likely 
result in a gross exaggeration of potential take.
    In addition, there are a number of factors indicating that the 
density we used should not result in an underestimate of take. Hauled-
out harbor seals are necessarily at haul-outs, and no significant 
harbor seal haul-outs are located within or near the action area. 
Harbor seals observed in the vicinity of the NBKB shoreline are rarely 
hauled-out (for example, in formal surveys during 2007-08, 
approximately 86 percent of observed seals were swimming), and when 
hauled-out, they do so opportunistically (i.e., on floating booms 
rather than established haul-outs). Harbor seals are typically unsuited 
for using manmade haul-outs at NBKB, which are used by sea lions. 
Primary harbor seal haul-outs in Hood Canal are located at significant 
distance (20 km or more) from the action area in Dabob Bay or further 
south (see Figure 4-1 in the Navy's application), meaning that animals 
casually entering the water from haul-outs or flushing due to some 
disturbance at those locations would not likely be exposed to 
underwater sound from the project; rather, only those animals embarking 
on foraging trips and entering the action area may be exposed. 
Moreover, because the Navy is unable to determine from field 
observations whether the same or different individuals are being 
exposed, each observation will be recorded as a new take, although an 
individual theoretically would only be considered as taken once in a 
given day.
    There are two final factors that support the conservatism of the 
1.31 density estimate: (1) Limited surveys conducted during 
construction in Hood Canal during off days in 2011 produced an 
uncorrected density estimate of approximately 0.55 seals/km\2\; and (2) 
although authorized to incidentally take 1,668 seals (corrected for 
actual number of pile driving days) during two projects conducted in 
Hood Canal in 2011, the total estimate of actual take (observed takes 
and observations extrapolated to unobserved area) was only 187 seals.
    Comment 3: The Commission recommends that we require the Navy to 
measure in-situ sound levels for 30 days after the initiation of major 
pile-driving scenarios and then provide the analytical results (i.e., 
sound levels as a function of distance) within an additional 15 days; 
if the Navy is unable to meet the 15-day analysis deadline, then 
require the Navy to use maximum distances to the Level A harassment 
thresholds of 190 dB re 1 [mu]Pa (i.e., 20 m for 36- and 48-in piles) 
and 180 dB re 1 [mu]Pa (i.e., 200 m for 36-in and 120 m for 48-in 
piles) from the test pile program until the in-situ sound measurement 
data have been analyzed and the distances to thresholds verified for 
EHW-2.
    Response: Because of difficulties implementing similar measures 
required under previous IHAs issued for activities conducted in 2011, 
which we have discussed at length with the Navy, we have determined 
that a requirement to adjust zones within 15 days of the completion of 
a 30-day acoustic monitoring period is impracticable in this situation. 
The Commission cites two projects in which adjustment of zones are 
required within a short timeframe; however, we do not believe that 
these projects offer comparable context as they are in a more sensitive 
environment (the Arctic) and are for activity with a larger footprint 
of more intense effect (seismic surveys). Given that the Navy is unable 
to meet the 15-day analysis deadline recommended by the Commission, we 
partially accept the Commission's alternative recommendation to use 
maximum distances to Level A harassment thresholds from empirical 
measurements completed in 2011. We will require the Navy to implement a 
20 m shutdown zone around all pile driving for pinnipeds, but will 
require only an 85 m shutdown zone for cetaceans. The rationale for 
this reduction from the recommendation is described in detail under the 
``Mitigation'' section, later in this document. However, although 
unable to meet the recommended 15-day analysis timeframe, the Navy (in 
addition to implementing the precautionary zones described here) will 
complete analysis of acoustic monitoring data and adjust zones as 
necessary no later than 90 days following the completion of the 
acoustic monitoring period.
    Comment 4: The Commission recommends that we require the Navy to 
conduct in-situ sound measurements if and when vibratory hammers are 
used concurrently and to use that information to ensure that it (1) 
expands appropriately the size of the Level B harassment zone for in-
water sounds, (2) monitors the entire expanded zone, and (3) estimates 
the resulting number of takes accurately.

[[Page 42286]]

    Response: As originally proposed, the Navy will be required to 
conduct acoustic monitoring for representative pile driving scenarios, 
including the multi-rig scenario (simultaneous use of three vibratory 
and one impact rig) comprising the maximum production of sound. These 
data will enable understanding of the size of the actual Level B 
harassment zone which, in concert with observational data, will produce 
a record of actual incidental take. As described frequently, it is not 
practicable for the Navy to monitor the entire Level B harassment zone. 
However, although the size of the Level B harassment zone may fluctuate 
based on the number of drivers in use if the zone is in fact smaller 
than the predicted zone, it is not possible for the predicted zone to 
grow as it is defined not by the predicted sound pressure levels but by 
the contours of the Hood Canal shoreline. The properties of decibel 
addition and the way that addition of multiple driving rigs is likely 
to affect the sound field were described in greater detail earlier in 
this document, under ``Distance to Sound Thresholds''.
    Comment 5: The Commission recommends that we require the Navy to 
implement soft-start procedures after 15 minutes if pile driving or 
removal was delayed or shut down because of the presence of a marine 
mammal within or approaching the shutdown zone.
    Response: We disagree with this recommendation. The Commission 
cites several reasons why pinnipeds may remain in a shutdown zone after 
shutdown and yet be undetected by observers during the 15 minute 
clearance period (e.g., perception and availability bias). While this 
is possible in theory, we find it extremely unlikely that an animal 
could remain undetected in such a small zone and under typical 
conditions in Hood Canal. The shutdown zone for pinnipeds has a 20 m 
radial distance, while typical observation conditions in the Hood Canal 
are excellent. We believe the possibility of a pinniped remaining 
undetected in the shutdown zone, in relatively shallow water, for 
greater than 15 minutes is discountable. A requirement to implement 
soft start after every shutdown or delay less than 30 minutes in 
duration would be impracticable, resulting in significant construction 
delays and therefore extending the overall time required for the 
project, and thus the number of days on which disturbance of marine 
mammals could occur.
    Comment 6: The Commission recommends that we require the Navy to 
develop a monitoring strategy that ensures it will be able to detect 
and characterize marine mammal responses to the pile driving and 
removal activities as a function of sound levels and distance from the 
pile driving and removal sites.
    Response: We believe that the Navy, in consultation with NMFS, has 
developed such a strategy. The Commission states that the goal is not 
simply to employ a strategy that ensures monitoring out to a certain 
distance, but rather to employ a strategy that provides the information 
necessary to determine if the construction activities have adverse 
effects on marine mammals and to describe the nature and extent of 
those effects. We agree with that statement, and note that the Navy 
does not simply monitor within defined zones, ignoring occurrences 
outside those zones. The mitigation strategy is designed to implement 
shutdown of activity only for marine mammal occurrence within 
designated zones, but all observations of marine mammals, and any 
observed behavior, whether construed as a reaction to project activity 
or not, are recorded, regardless of distance to project activity. This 
information is coupled with acoustic monitoring data (i.e., sound 
levels recorded at multiple defined distances from the activity) to 
draw conclusions about the impact of the activity on marine mammals. 
Additionally, the larger monitoring effort conducted by the Navy in 
deeper waters of Hood Canal during their 2011 project monitoring was an 
important piece of the Navy's overall monitoring strategy for the 
ongoing suite of actions at NBKB and may reasonably be used as a 
reference for the current activities. Using that information, as well 
as the results of a more limited deep-water component of the monitoring 
program for 2012, we can gain an acceptable understanding of marine 
mammal occurrence and behavior within the Level B harassment zone in 
deeper waters beyond the waterfront restricted area, which is 
intensively monitored. It is unclear what aspects of the monitoring 
goals or strategy the Commission deems inadequate.
    Comment 7: The Commission recommends that we complete an analysis 
of the impact of the proposed activities together with the cumulative 
impacts of all the other pertinent risk factors (including but not 
limited to the Navy's concurrent EHW-1 repair project) impacting marine 
mammals in the Hood Canal area prior to issuing the proposed incidental 
harassment authorization.
    Response: Section 101(a)(5)(D) of the MMPA requires NMFS to make a 
determination that the harassment incidental to a specified activity 
will have a negligible impact on the affected species or stocks of 
marine mammals, and will not result in an unmitigable adverse impact on 
the availability of marine mammals for taking for subsistence uses. 
Neither the MMPA nor NMFS' implementing regulations specify how to 
consider other activities and their impacts on the same populations. 
However, consistent with the 1989 preamble for NMFS' implementing 
regulations (54 FR 40338; September 29, 1989), the impacts from other 
past and ongoing anthropogenic activities are incorporated into the 
negligible impact analysis via their impacts on the environmental 
baseline (e.g., as reflected in the density/distribution and status of 
the species, population size and growth rate, and ambient noise).
    In addition, cumulative effects were addressed in the Navy's 
Environmental Impact Statement and in the biological opinion prepared 
for this action. These documents, as well as the relevant Stock 
Assessment Reports, are part of NMFS' Administrative Record for this 
action, and provided the decision-maker with information regarding 
other activities in the action area that affect marine mammals, an 
analysis of cumulative impacts, and other information relevant to the 
determination made under the MMPA.
    Comment 8: The Commission recommends that we encourage the Navy to 
combine future requests for incidental harassment authorizations for 
all activities that would occur in the same general area and within the 
same year rather than segmenting those activities and their associated 
impacts by requesting separate authorizations.
    Response: We agree with the Commission's recommendation and have 
encouraged the Navy to do so.
    Comment 9: The Commission recommends that we adopt a policy to 
provide an additional opportunity for public review and comment before 
amending authorizations if any substantive changes are made to them 
after they have been issued or if the information on which a negligible 
impact determination is based is significantly changed in a way that 
indicates the likelihood of an increased level of taking or impacts not 
originally considered.
    Response: We disagree with the Commission's contention that the 
referenced IHA modifications constituted a substantive change. The 
modifications involved small increases to the amount of incidental take 
of harbor porpoise authorized for two

[[Page 42287]]

projects conducted in 2011 at NBKB in response to new information about 
harbor porpoise occurrence and habitat use at NBKB. In our findings for 
the referenced modification, we determined that authorization of the 
incidental taking, by Level B harassment only, of increased numbers of 
harbor porpoise did not alter the original scope of activity analyzed, 
the monitoring and mitigation measures implemented, or the impact 
analysis in a manner that materially affected the basis for our 
original findings. The increased level of authorized take for harbor 
porpoise remained a small number, by any definition of that term. The 
Inland Washington stock of harbor porpoise is not listed under the ESA, 
nor is it considered depleted or designated as a strategic stock under 
the MMPA. The increase in takings was considered negligible in 
comparison with the overall population of the stock. The modifications 
reflected a more complete understanding of harbor porpoise presence and 
use of habitat in the Hood Canal, but constituted a negligible increase 
in impacts to the stock. We believe that those modifications were 
within the scope of analysis supporting the determinations for the 
original IHAs, and that those original findings remained valid. 
Nevertheless, we thank the Commission for the recommendation and will 
consider it in the future for situations where substantive changes are 
required.

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. The FR notice (76 FR 79410; December 21, 
2011) summarizes the population status and abundance of these species 
and provides detailed life history information. A description of the 
humpback whale is provided here, as the recent sighting of an 
individual of that species occurred after the FR notice was published.

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 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 2011 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; 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 last reported

[[Page 42288]]

sighting was on February 17, 2012, and the individual has almost 
certainly departed the 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.

Potential Effects of the Specified Activity on Marine Mammals

    We have determined that pile driving, as outlined in the project 
description, has the potential to result in behavioral harassment of 
marine mammals that may be present in the project vicinity while 
construction activity is being conducted. Pile driving could 
potentially harass those pinnipeds that are in the water close to the 
project site, whether exposed to airborne or underwater sound. The FR 
notice (76 FR 79410; December 21, 2011) provides a detailed description 
of marine mammal hearing and of the potential effects of these 
construction activities on marine mammals.

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 driving effects on likely marine mammal prey (i.e., fish) near 
NBKB and minor impacts to the immediate substrate during construction 
activity associated with the EHW-2 project. The FR notice (76 FR 79410; 
December 21, 2011) describes these potential impacts in greater detail.

Mitigation

    In order to issue an incidental take authorization (ITA) under 
Section 101(a)(5)(D) of the MMPA, we 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).
    A combination of predictions--based on proxy values and practical 
spreading loss--and measured values for zones of influence (ZOIs; see 
``Estimated Take by Incidental Harassment'') were used to develop 
mitigation measures for pile driving activities at NBKB. The ZOIs 
effectively represent the mitigation zone that would be established 
around each pile to prevent Level A harassment to marine mammals, while 
providing estimates of the areas within which Level B harassment might 
occur. In addition to the 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 driving 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 driving, if a 
marine mammal comes within 10 m, operations shall cease and vessels 
shall reduce speed to the minimum level required to

[[Page 42289]]

maintain steerage and safe working conditions. This type of work could 
include the following activities: (1) Movement of the barge to the pile 
location; (2) positioning of the pile on the substrate via a crane 
(i.e., stabbing the pile); (3) removal of the pile from the water 
column/substrate via a crane (i.e., deadpull); or (4) the placement of 
sound attenuation devices around the piles. For these activities, 
monitoring would take place from 15 minutes prior to initiation until 
the action is complete.

Monitoring and Shutdown for Pile Driving

    The following measures would apply to the Navy's mitigation through 
shutdown and disturbance zones:
    Shutdown Zone--For all pile driving activities, the Navy will 
establish a shutdown zone intended to contain 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. Predictions 
indicate (and empirical measurements generally confirm) that radial 
distances to the 190-dB threshold will typically be less than 10 m for 
impact pile driving or, in the case of vibratory pile driving, would 
not exist because source levels are lower than the threshold. However, 
shutdown zones for pinnipeds will conservatively be set at a minimum 20 
m during impact pile driving and 10 m during vibratory pile driving. 
For impact pile driving, the distance corresponds with the largest 
distance to the 190 dB threshold measured during 2011 acoustic 
monitoring. These precautionary measures are intended to further reduce 
any possibility of injury to pinnipeds by incorporating a buffer to the 
190-dB threshold within the shutdown area.
    For cetaceans, the distance to the shutdown zone corresponding to 
the 180-dB threshold will be set at 85 m for impact pile driving and 10 
m for vibratory pile driving. There is little risk of injury to 
cetaceans, as none have ever been observed entering the port security 
barrier (PSB) delineating the waterfront restricted area (WRA) at NBKB. 
Cetaceans are capable of passing underneath this barrier, which lies at 
variable distances from the construction site but is approximately 500 
m distant in the direction of the deeper waters of Hood Canal where 
cetaceans might be expected to occur, but have not been observed to do 
so. It is unknown whether cetaceans do not enter the WRA because of the 
physical presence of the PSB, the lack of attraction to shallower-water 
habitats, or another reason. For impact pile driving, the mean of all 
data points is approximately 64 m to threshold; however, the maximum 
value recorded was 200 m. While it may be argued that a precautionary 
approach similar to that employed for the 190-dB zone is warranted, in 
which the shutdown zone encompasses the largest measured value, it is 
our view that use of such a large zone for cetaceans would distract 
from biological monitors' primary task of ensuring that no pinnipeds 
(the only animals expected to occur within the WRA) are exposed to 
sounds that may result in injury. As described previously, no cetaceans 
are expected--and none have ever been observed--so close to the 
construction area. Therefore, while some degree of precaution is 
warranted for cetaceans, the larger zone (200 m) would detract from the 
Navy's ability to effectively mitigate the possibility of pinniped 
injury while conferring no additional benefit on cetaceans. In order to 
determine a reasonable shutdown zone for cetaceans during impact pile 
driving, we examined the available data, which show two clusters at 20 
m and under (9 of 22 data points) and between 50-120 m (11 of 22 data 
points). The mean of this second cluster is found at 85 m; this 
distance encompasses approximately 65 percent of measurements. We 
emphasize again that establishment of this zone is intended only as a 
precautionary measure as no cetaceans have been observed within the 
WRA.
    Disturbance Zone--Disturbance zones are typically defined as the 
area in which SPLs equal or exceed 160 or 120 dB rms (for pulsed or 
non-pulsed sound, respectively). Because the 120 dB zone would always 
subsume the 160 dB zone under the multi-rig scenario considered here, 
the 160 dB harassment zone is not considered further. Disturbance zones 
provide utility for monitoring conducted for mitigation purposes (i.e., 
shutdown zone monitoring) by establishing monitoring protocols for 
areas adjacent to the shutdown zones. Monitoring of disturbance zones 
enables observers to be aware of and communicate the presence of marine 
mammals in the project area but outside the shutdown zone and thus 
prepare for potential shutdowns of activity. However, the primary 
purpose of disturbance zone monitoring is for documenting incidents of 
Level B harassment; disturbance zone monitoring is discussed in greater 
detail later (see 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.
    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 
zone for vibratory pile driving, predicted to encompass an area of 41.4 
km\2\), the disturbance zone may be defined as some area that may 
reasonably be monitored or, alternatively, is a de facto zone defined 
by the distance that monitors are capable of observing from defined 
deployment locations. In this situation, the bulk of monitoring (as 
described in the Navy's Marine Mammal Monitoring Plan) will be focused 
within the WRA and on the shutdown zones. One observer will be 
designated specifically to monitor shutdown zones for each active pile 
driving rig, with one additional observer tasked with monitoring 
additional areas outside of the shutdown zones but within the WRA. It 
is unlikely that observers stationed within the WRA will be able to 
effectively monitor any area outside of the WRA, due to distance from 
the observer as well as the physical presence of the PSB. However, 
during the period of acoustic monitoring, a vessel will be stationed 
outside of the WRA and will carry a biological monitor. This period 
will occur for no less than 30 days and is expected to provide 
verification of assumptions regarding the distribution and frequency of 
occurrence of animals in the deeper waters of Hood Canal that have been 
developed from literature, past monitoring and reports, and marine 
mammal monitoring conducted at NBKB in 2011.
    In order to document observed incidences of harassment, monitors 
record all marine mammal observations, regardless of location. The 
observer's location, as well as the location of the pile being driven, 
is known from a GPS. The location of the animal is estimated as a 
distance from the observer, which is then compared to the location from 
the pile. If acoustic monitoring is being conducted for that pile, a 
received SPL may be estimated, or the received level may be estimated 
on the basis of past or subsequent acoustic monitoring. It may then be 
determined whether the animal was exposed to sound levels constituting 
incidental harassment in post-processing of observational and acoustic 
data, and a precise accounting of observed incidences of harassment 
created. Therefore, although the predicted distances to behavioral 
harassment thresholds are useful for

[[Page 42290]]

estimating incidental harassment for purposes of authorizing levels of 
incidental take, actual take may be determined in part through the use 
of empirical data. That information may then be used to extrapolate 
observed takes to reach an approximate understanding of actual total 
takes.
    Monitoring Protocols--Monitoring would be conducted before, during, 
and after pile driving activities, with minimum 20 m/85 m shutdown 
zones surrounding each pile for pinnipeds and cetaceans, respectively. 
In addition, observers shall record all incidences of marine mammal 
occurrence, regardless of distance from activity, and shall document 
any behavioral reactions in concert with distance from piles being 
driven. Observations made outside the shutdown zone will not result in 
shutdown; that pile segment would be completed without cessation, 
unless the animal approaches or enters the shutdown zone, at which 
point all pile driving activities would be halted. Please see the 
Marine Mammal Monitoring Plan (available at https://www.nmfs.noaa.gov/pr/permits/incidental.htm), developed by the Navy in agreement with us, 
for full details of the monitoring protocols.
    Detailed observations outside the WRA, as defined by the PSB, are 
likely not possible, and it would be impossible for the Navy to account 
for all individuals occurring within the full disturbance zone with any 
degree of certainty. Monitoring will take place from 15 minutes prior 
to initiation through 30 minutes post-completion of pile driving 
activities. Pile driving activities include the time to remove a single 
pile or series of piles, as long as the time elapsed between uses of 
the pile driving equipment is no more than 30 minutes.
    The following additional measures apply to visual monitoring:
    (1) Monitoring will be conducted by qualified observers. A minimum 
of one observer shall be employed to observe shutdown zones for each 
active pile driving rig, in addition to one observer tasked with 
monitoring the area outside of the shutdown zones. For the multi-rig 
scenario using three vibratory drivers and one impact driver 
simultaneously, this would result in a minimum total of five observers. 
In addition, at least one observer shall be positioned on the acoustic 
monitoring vessel outside the WRA for as long as that vessel is 
present, but for no less than 30 days. 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.
    Trained observers will be placed at the best vantage point(s) 
practicable, as defined in the Navy's Marine Mammal Monitoring Plan, to 
monitor for marine mammals and implement shutdown or delay procedures 
when applicable by calling for the shutdown to the equipment operator.
    (2) Prior to the start of pile driving activity, the shutdown zone 
will be monitored for 15 minutes to ensure that it is clear of marine 
mammals. Pile driving will only commence once observers have declared 
the shutdown zone clear of marine mammals; animals will be allowed to 
remain in the shutdown zone (i.e., must leave of their own volition) 
and their behavior will be monitored and documented. The shutdown zone 
may only be declared clear, and pile driving started, when the entire 
shutdown zone is visible (i.e., when not obscured by dark, rain, fog, 
etc.).
    (3) If a marine mammal approaches or enters the shutdown zone 
during the course of pile driving operations, activity will be halted 
and delayed until either the animal has voluntarily left and been 
visually confirmed beyond the shutdown zone or 15 minutes have passed 
without re-detection of the animal. Monitoring will be conducted 
throughout the time required to drive a pile. Under certain 
construction circumstances where initiating the shutdown and clearance 
procedures would result in an imminent concern for human safety, to be 
determined by the on-site construction supervisor in consultation with 
the lead observer, the shutdown provision may be waived.
    (4) All shutdown zones will be established as described. However, 
in-situ acoustic monitoring will be utilized to determine the actual 
distances to these threshold zones, and the size of the shutdown zones 
will be adjusted accordingly based on received SPLs. We have determined 
that real-time adjustment of zones is impracticable, considering the 
resources required to implement such a measure, the nature of the 
activity, and the existence of empirical data from 2011 acoustic 
monitoring upon which precautionary zones may be based. Zones shall be 
adjusted as necessary upon provision of the draft acoustic monitoring 
report from contractors to the Navy, no later than 90 days from the end 
of the acoustic monitoring period. However, the precautionary shutdown 
zone established for pinnipeds (i.e., 20 m) would not be decreased.

Sound Attenuation Devices

    Bubble curtains shall be used during all impact pile driving. 
Testing of the device, accomplished by comparing measurements of 
attenuated and unattenuated strikes, is not possible because of 
requirements in place to protect marbled murrelets (an ESA-listed bird 
species under the jurisdiction of the USFWS). In the absence of 
testing, the Navy shall ensure, through whatever means possible (e.g., 
requirements in contract language regarding the device selected for use 
and measures ensuring proper deployment of the device), that the device 
is capable of achieving mean performance of 10 dB attenuation although 
a high degree of performance variability may be expected.

Timing Restrictions

    The Navy has set timing restrictions for pile driving 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. The initial months (July to 
September) of the timing window overlap with times when Steller sea 
lions are not expected to be present within the project area and

[[Page 42291]]

California sea lions may be expected to be less numerous.

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 construction project will utilize soft-start 
techniques (ramp-up and dry fire) for impact and vibratory pile 
driving. 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 is repeated two additional 
times. For impact driving, contractors will be required to provide an 
initial set of three strikes from the impact hammer at 40 percent 
energy, followed by a 30-second waiting period, then two subsequent 
three strike sets.

Daylight Construction

    Impact pile driving during the first half of the in-water work 
window (July 16 to September 15) would only occur between 2 hours after 
sunrise and 2 hours before sunset to protect breeding marbled 
murrelets. Vibratory pile driving and other construction activities 
occurring in the water between July 16 and September 15 could occur 
during daylight hours (sunrise to sunset). Between September 16 and 
February 15, construction activities occurring in the water would occur 
during daylight hours (sunrise to sunset).

Mitigation Effectiveness

    It should be recognized that although marine mammals would be 
protected from Level A harassment by the utilization of a bubble 
curtain and monitoring of the near-field injury zones, monitoring is 
not likely to be 100 percent effective at all times in locating marine 
mammals in the waters surrounding the shutdown zone and may not be 100 
percent effective in detecting animals even within the shutdown zone. 
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), the behavior and depth of the 
animal, and monitoring platforms.
    All observers employed for mitigation activities would be 
experienced biologists with training in marine mammal detection and 
behavior. Based on the specialized training required of observers and 
the small shutdown zones, we expect that visual mitigation will be 
highly effective. 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. In 
addition, conditions at NBKB--relatively calm wind and sea conditions 
throughout most of the year--are conducive to effective visual 
monitoring.
    We have carefully evaluated the applicant's mitigation measures and 
considered a range of other measures in the context of ensuring that we 
prescribe the means of effecting the least practicable impact on the 
affected marine mammal species and stocks and their habitat. Our 
evaluation of potential measures included consideration of the 
following factors in relation to one another: (1) The manner in which, 
and the degree to which, the successful implementation of the measure 
is expected to minimize adverse impacts to marine mammals; (2) the 
proven or likely efficacy of the specific measure to minimize adverse 
impacts as planned; and (3) the practicability of the measure for 
applicant implementation, 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 or recommended by NMFS biologists, 
the Navy, and the Commission, we have determined that these 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.

Monitoring and Reporting

    In order to issue an ITA for an activity, section 101(a)(5)(D) of 
the MMPA states that we 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. Please see the Navy's Marine 
Mammal and Acoustic Monitoring Plans for full details of the 
requirements for monitoring and reporting.

Acoustic Measurements

    Within the first 30 days of pile driving, the Navy will capture a 
representative acoustic sample of the major pile driving scenarios 
under the modeled conditions (impact hammer and vibratory driving, 
smaller [24-in to 36-in] and larger [48-in] piles, plumb and batter 
piles). All measurements will be made with the sound attenuation 
measures discussed previously in place. Maximum sound pressure levels, 
as well as approximate distances to relevant thresholds, will be 
measured and documented. Airborne acoustic monitoring will also be 
conducted during impact and vibratory pile driving. Acoustic monitoring 
will be conducted in accordance with the Acoustic Monitoring Plan 
developed by the Navy and approved by us. Please see that plan, 
available at https://www.nmfs.noaa.gov/pr/permits/incidental.htm, for 
full details of the required acoustic monitoring.
    Some details of the methodology include:
     For underwater recordings, a stationary hydrophone system 
with the ability to measure SPLs at mid-water depth and approximately 1 
m from the bottom, (taking tidal changes into account) will be placed 
at a distance of 10 m from the source. The hydrophone will be deployed 
so as to maintain a constant distance of 10 m from the pile.
     For airborne recordings, reference recordings will be 
attempted at approximately 50 ft (15.2 m) from the source via a 
stationary hydrophone. However, other distances may be utilized to 
obtain better data if the pile driving signal cannot be isolated 
clearly due to other sound sources (e.g., barges or generators). The 
best professional judgment of the contractor employed to implement the 
monitoring will be sufficient to ensure the monitoring objectives are 
achieved.
     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. Unattended 
hydrophones located in the far-field will be checked regularly to 
ensure that equipment failure or other technical difficulty, such as 
strumming, does not render measurements unusable. Other hydrophones and 
microphones would be placed at other distances and/or depths and moved 
as necessary to determine the distance to the thresholds for marine 
mammals. At a minimum, one attended platform will be located in the 
far-field (i.e., outside the WRA) for the duration of acoustic 
monitoring.

[[Page 42292]]

Visual Marine Mammal Observations

    The Navy will collect sighting data and behavioral responses to 
construction for marine mammal species observed in the region of 
activity during the period of activity. All observers will be trained 
in marine mammal identification and behaviors and are required to have 
no other construction-related tasks while conducting monitoring.
    The Navy will monitor the shutdown zone and disturbance zone within 
the WRA before, during, and after pile driving as described under 
mitigation and in the Marine Mammal Monitoring Plan. There will, at all 
times, be at least one observer stationed at an appropriate vantage 
point to observe the shutdown zones associated with each operating 
hammer and at least one additional observer stationed to observe waters 
outside the shutdown zones but within the WRA. In addition, at least 
one marine mammal observer would be stationed on a vessel conducting 
acoustic monitoring outside the WRA, for as long as such monitoring is 
conducted but for a minimum of 30 days. The Navy estimates that 
representative acoustic sampling may occur in approximately 30 days. 
Based on our requirements, the Marine Mammal Monitoring Plan would 
include the following procedures for pile driving:
    (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.
    (2) During all observation periods, observers will use binoculars 
and the naked eye to search continuously for marine mammals.
    (3) If the shutdown zones are obscured by fog or poor lighting 
conditions, pile driving at that location will not be initiated until 
that zone is visible.
    (4) The shutdown and disturbance zones around the pile will be 
monitored for the presence of marine mammals before, during, and after 
any pile driving or removal activity.
    Individuals implementing the monitoring protocol will assess its 
effectiveness using an adaptive approach. Monitoring biologists will 
use their best professional judgment throughout implementation and seek 
improvements to these methods when deemed appropriate. Any 
modifications to protocol will be coordinated between us and the Navy.

Data Collection

    We require that observers use approved data forms. Among other 
pieces of information, the Navy will record detailed information about 
any implementation of shutdowns, including the distance of animals to 
the pile and description of specific actions that ensued and resulting 
behavior of the animal, if any. We require that, at a minimum, the 
following information be collected on the sighting forms:
    (1) Date and time that pile driving 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 driving activities to marine mammals and 
distance from the marine mammals to the observation point;
    (8) Locations of all marine mammal observations; and
    (9) Other human activity in the area.

Reporting

    A draft report will be submitted within 90 days of the completion 
of the first 30 days of acoustic measurements and marine mammal 
monitoring. The report will also provide descriptions of any problems 
encountered in deploying sound attenuating devices and actions taken to 
solve these problems, any adverse responses to construction activities 
by marine mammals, and a complete description of all mitigation 
shutdowns and the results of those actions. A final report would be 
prepared and submitted within 30 days following resolution of comments 
on the draft report. Within 90 days of the end of the in-water work 
period, a draft comprehensive report on all marine mammal monitoring 
conducted under the IHA will be submitted to NMFS. The report will 
include marine mammal observations pre-activity, during-activity, and 
post-activity during pile driving days. A final report will be prepared 
and submitted within 30 days following resolution of comments on the 
draft report. Required contents of the monitoring reports are described 
in more detail in the relevant plans.

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. It is unlikely that injurious or lethal 
takes would occur even in the absence of the planned mitigation and 
monitoring measures; however, implementation of these measures is 
expected to minimize the possibility of such takes to discountable 
levels.
    If a marine mammal responds to a stimulus by changing its behavior 
(e.g., through relatively minor changes in locomotion direction/speed 
or vocalization behavior), the response may or may not constitute 
taking at the individual level, and is unlikely to affect the stock or 
the species as a whole. However, if a sound source displaces marine 
mammals from an important feeding or breeding area for a prolonged 
period, impacts on animals or on the stock or species could potentially 
be significant (Lusseau and Bejder, 2007; Weilgart, 2007). Given the 
many uncertainties in predicting the quantity and types of impacts of 
sound on marine mammals, it is common practice to estimate how many 
animals are likely to be present within a particular distance of a 
given activity, or exposed to a particular level of sound. This 
practice potentially overestimates the numbers of marine mammals taken. 
For example, during the past ten years, killer 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. Although incidental take 
of killer whales and Dall's porpoises was authorized for 2011 
activities at NBKB on the basis of past observations of these species, 
no such takes were recorded and no individuals of these species were 
observed. Similarly, estimated actual take levels (observed takes 
extrapolated to the remainder of unobserved but ensonified area) were 
significantly less than authorized levels of take for the remaining 
species.
    The project area is not believed to be particularly important 
habitat for marine mammals, nor is it considered an area frequented by 
marine mammals, although harbor seals are year-round

[[Page 42293]]

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 these activities are expected to affect only a 
relatively small number of individual marine mammals, although those 
effects could be recurring over the life of the project if the same 
individuals remain in the project vicinity.
    The Navy has requested authorization for the 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 driving during construction 
activities associated with the wharf construction project described 
previously in this document. The humpback whale is not expected to 
occur in the project area. 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, which were described in detail 
in the FR notice. Please see that document for an in-depth discussion 
(76 FR 79410; December 21, 2011).
    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, 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 2-2 of the Navy's application; the WRA security 
barrier, which is not denoted in the figure legend, is represented by a 
thin gray line and is roughly 500 m from the project site). Although 
the Navy will implement a precautionary shutdown zone for cetaceans, 
anecdotal evidence suggests that cetaceans 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. 
The methodology for estimating take was described in detail in the FR 
notice (76 FR 79410; December 21, 2011). The ZOI impact area is the 
estimated range of impact to the sound criteria. The distances 
specified in Table 2 were used to calculate ZOI around each pile. All 
impact pile driving take calculations were based on the estimated 
threshold ranges using a bubble curtain with 10 dB attenuation as a 
mitigation measure. The ZOI impact area took into consideration the 
possible affected area of the Hood Canal from the pile driving 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. Although mean distances to thresholds 
as determined during acoustic monitoring in 2011 may differ somewhat--
primarily in that the distances to the 120 dB threshold are likely to 
be much smaller for vibratory removal--we have maintained the take 
estimated based on predicted distances, as analyzed in the notice of 
proposed authorization. Therefore, these take estimates are likely to 
be conservative.
    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 driving day. Thus, for 
these two species, take is estimated by multiplying abundance by days 
of activity (195 days). While pile driving can occur any day throughout 
the in-water work window, and the analysis is conducted on a per day 
basis, only a fraction of that time (typically a matter of hours on any 
given day) is actually spent pile driving.
    The exposure assessment methodology is an estimate of the numbers 
of individuals exposed to the effects of pile driving activities 
exceeding relevant thresholds. Of note in these exposure estimates, 
mitigation methods other than the use of a sound attenuation device 
(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 resulting solely 
from airborne sound are likely, as even the larger distances to the 
harassment thresholds seen in acoustic monitoring from 2011 would not 
reach any areas where pinnipeds may haul out (although predicted 
distances to the 90 dB threshold using proxy values would reach the 
nearest portion of the PSB). The shortest distance to the PSB (where 
harbor seals and the occasional California sea lion may haul-out) is 
approximately 180 m, but is generally greater than 500 m at the project 
site. Submarines docked at Delta Pier, where California and Steller sea 
lions are known to haul-out, are approximately 1.2 km from the project 
site. We recognize that it is possible that airborne sound could reach 
portions of the PSB where seals may haul-out, and that pinnipeds in the 
water could be

[[Page 42294]]

exposed to airborne sound that may result in behavioral harassment when 
looking with heads above water. However, these animals would previously 
have been `taken' as a result of exposure to underwater sound above the 
behavioral harassment thresholds, which are in all cases larger than 
those associated with airborne sound. Thus, the behavioral harassment 
of these animals is already accounted for in these estimates of 
potential take. Multiple incidents of exposure to sound above NMFS' 
thresholds for behavioral harassment are not believed to result in 
increased behavioral disturbance, in either nature or intensity of 
disturbance reaction. Therefore, although we initially proposed the 
authorization of incidental take resulting from airborne sound for 
harbor seals, we no longer believe that such authorization is 
warranted.
    The derivation of density or abundance estimates for each species, 
as well as further description of the rationale for each take estimate, 
was described in detail in the FR notice (76 FR 79410; December 21, 
2011). Total take estimates, and numbers of take per species to be 
authorized, are presented in Table 4.

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 site from 
September through mid-June. 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). 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 pile driving encompasses areas 
where California sea lions are known to haul-out; assuming that 26 
individuals could be taken per day of pile driving provides an estimate 
of 5,070 takes for that activity. Table 4 depicts the number of 
estimated 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.
    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 have indicated that Steller 
sea lions are present only from October through April and not during 
the summer months.
    Steller sea lions are known only from haul-outs over one mile from 
the project area. The ZOI for vibratory pile driving encompasses areas 
where Steller sea lions are known to haul-out; assuming that one 
individual could be taken per day of pile driving provides an estimate 
of 195 takes, the level of take which was proposed for authorization 
(76 FR 79410; December 21, 2011). However, in consultation with the 
Navy, we now believe that the available abundance information does not 
necessarily reflect the nature of Steller sea lion occurrence at NBKB 
(i.e., the take estimation assumes that only one animal would be 
present per day). Actual observational data show that, while their 
occurrence is concentrated near Delta Pier, they occur in groups of one 
to four individuals. As a result, it is more likely that more than one 
exposure would occur in a day. In order to reflect this, we believe it 
warranted to authorize take at the level of two individuals per day of 
pile driving, for a total of 390 takes. Table 4 depicts the number of 
estimated behavioral harassments.

Harbor Seal

    Harbor seals are the most abundant marine mammal in Hood Canal, and 
they can occur anywhere in Hood Canal waters year-round. 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 driving. 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. 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. Table 4 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 was last 
reported on February 23, 2012, indicating that the animal has almost 
certainly left the area. 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. We 
consider it extremely unlikely that any humpback whales would be 
present during the project timeframe. Therefore, the likelihood of 
incidental take of humpback whales is discountable and none is 
authorized.

Killer Whales

    Transient killer whales are uncommon visitors to Hood Canal. 
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

[[Page 42295]]

feeding. 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\]). Because the 
timeframe of known transient killer whale occurrence in Hood Canal only 
partially overlaps the construction period (January to mid-February), 
the days of total activity (or days of potential exposure) portion of 
the formula is reduced to 45 for killer whales. Table 4 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. One individual has been observed by Navy staff in deeper waters 
of Hood Canal. Table 4 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 
observed. However, during monitoring of Navy actions in 2011, 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.) and 
made regular observations of harbor porpoise groups. Please note that, 
due to the availability of corrected trackline distances for harbor 
porpoise surveys conducted in 2011, that density estimate has been 
revised from 0.250 animals/km\2\ to 0.231 animals/km\2\ for survey data 
through September 28, 2011.
    Potential takes could occur if individuals of these species are 
present in the vicinity when pile driving 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 driving. Potential takes 
by disturbance would likely have a negligible short-term effect on 
individuals and not result in population-level impacts.

     Table 4--Number of Potential Incidental Takes of Marine Mammals Within Various Acoustic Threshold Zones
----------------------------------------------------------------------------------------------------------------
                                                            Underwater               Airborne
                                                 ------------------------------------------------
                                     Density/                        Vibratory                    Total proposed
             Species                 abundance     Impact injury    disturbance       Impact        authorized
                                                   threshold \1\     threshold      disturbance        takes
                                                                   (120 dB) \2\    threshold \3\
----------------------------------------------------------------------------------------------------------------
California sea lion.............      \4\ 26.2                 0           5,070               0           5,070
Steller sea lion................       \4\ 1.2                 0             390               0             390
Harbor seal.....................           1.31                0          10,530               0          10,530
Killer whale....................           0.038               0              90             N/A              90
Dall's porpoise.................           0.014               0             195             N/A             195
Harbor porpoise.................           0.231               0           1,950             N/A           1,950
                                 -------------------------------------------------------------------------------
    Total.......................  ..............               0          18,225               0          18,225
----------------------------------------------------------------------------------------------------------------
\1\ Acoustic injury threshold for impact pile driving is 190 dB for pinnipeds and 180 dB for cetaceans.
\2\ The 160-dB acoustic harassment zone associated with impact pile driving would always be subsumed by the 120-
  dB harassment zone produced by vibratory driving. Therefore, takes are not calculated separately for the two
  zones.
\3\ Acoustic disturbance threshold is 100 dB for sea lions and 90 dB for harbor seals. We believe that any
  animal subject to levels of airborne sound that may result in harassment--whether hauled-out or in the water--
  would likely also be exposed to underwater sound above behavioral harassment thresholds within the same day.
  Therefore, no take authorization specific to airborne sound is warranted.
\4\ 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 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 driving activities associated with the wharf construction 
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 airborne or underwater sounds generated from 
pile driving. No mortality, serious injury, or Level A harassment is 
anticipated given the methods of installation and measures designed to 
minimize the possibility of injury to marine mammals and Level B 
harassment will be reduced to the level of least practicable adverse 
impact. Specifically, vibratory hammers, which do not have significant 
potential to cause injury to marine mammals due to the relatively low 
source levels produced (less than 190 dB), will be the primary method 
of installation. Also, no impact pile driving will occur without the 
use of a sound attenuation system (e.g., bubble curtain), and pile 
driving will either not start or be halted if marine mammals approach 
the shutdown zone. The pile driving activities analyzed here are 
similar to other nearby construction activities within the Hood Canal, 
including two recent projects conducted by the Navy at the same 
location (test pile project and EHW-1 pile replacement project) as well 
as work conducted in 2005 for the Hood Canal Bridge (SR-104) by the 
Washington Department of Transportation, which have taken place with no 
reported injuries or mortality to marine mammals.

[[Page 42296]]

    The numbers of authorized take for Steller and California sea lions 
and for Dall's porpoises would be considered small relative to the 
relevant stocks or populations (each less than two percent) even if 
each estimated taking occurred to a new individual--an extremely 
unlikely scenario. The proposed numbers of authorized take for harbor 
seals, transient killer whales, and harbor porpoises are somewhat 
higher relative to the total stocks. However, these numbers represent 
the 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. While the available information and formula 
estimate that as many as 10,530 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 driving 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. Similarly, for killer whales, the estimated number of 
takes represents a single group of eleven whales that could potentially 
be exposed to sound on multiple days, if present. In fact, if a group 
of transient killer whales was present in the Hood Canal during the 
project (which is in itself unlikely, as such groups have appeared only 
twice since 2003), such a group would be able to simply leave the 
project area and forage elsewhere in Hood Canal or Puget Sound if the 
acoustic behavioral harassment caused by the project disturbed the 
group to a sufficient degree. However, it is difficult to quantify such 
a group's willingness to remain in the presence of behavioral 
harassment or, alternatively, to depart the project area. As such, NMFS 
proposes to authorize the take presented in Table 4, which represents 
the take of a single pod (approximately 11) that might be taken 
repeatedly over multiple days if they stayed in the area. The possible 
repeated exposure of a small group of individuals to levels associated 
with Level B harassment in this area is expected to have a negligible 
impact on the stock.
    For harbor porpoises, the situation relative to the regional stock 
(where estimated take is approximately 18 percent) is less clear as 
little is known about their use of Hood Canal. Sightings information 
from opportunistic waterfront surveys as well as designed surveys of 
nearshore waters had previously indicated that harbor porpoises rarely 
occurred in NBKB waters. In addition, although no systematic survey 
work for harbor porpoises has occurred in Hood Canal, anecdotal 
evidence and expert opinion received through personal communication had 
confirmed that harbor porpoises were expected to occur infrequently and 
in low numbers in the project area. Recent Navy surveys have indicated 
that harbor porpoises are present in greater numbers than had been 
believed. It is unclear from the limited information available what 
relationship this occurrence, recorded only during the fall of 2011, 
may hold to the regional stock or whether similar usage of Hood Canal 
may be expected to recur throughout the project timeframe. 
Nevertheless, the estimated take of harbor porpoises is likely an 
overestimate (as it is based on information that may not hold true 
throughout the project timeframe) and should be considered to present a 
negligible impact on the stock. Harbor porpoise sightings to date have 
occurred only at significant distance from the project area (both 
inside and outside of the predicted 120-dB zone).
    We have determined that the impact of the previously described 
wharf construction project may result, at worst, in a temporary 
modification in behavior (Level B harassment) of small numbers of 
marine mammals. No mortality or injuries are anticipated as a result of 
the specified activity, and none will 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 will 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 will have an insignificant short-term effect on 
individuals and will 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.
    The negligible impact determination is also supported by the 
likelihood that, given sufficient ``notice'' through mitigation 
measures including soft start, marine mammals are expected to move away 
from a sound source that is annoying prior to its becoming potentially 
injurious, and the likelihood that marine mammal detection ability by 
trained observers is high under the environmental conditions described 
for Hood Canal, enabling the implementation of shutdowns to avoid 
injury, serious injury, or mortality. As a result, no take by injury or 
death is anticipated, and the potential for temporary or permanent 
hearing impairment is very low and would be avoided through the 
incorporation of the described mitigation measures.
    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 will be mitigated to the lowest level 
practicable through incorporation of the 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, we find that the wharf construction project will result in 
the incidental take of small numbers of marine mammals, by Level B 
harassment only, and that the total taking from the activity will have 
a negligible impact on the affected species or stocks.

[[Page 42297]]

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 will 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 activities. 
Therefore, no relevant subsistence uses of marine mammals are 
implicated by this action.

Endangered Species Act (ESA)

    There is one ESA-listed marine mammal species with known occurrence 
in the project area: The Eastern DPS of the Steller sea lion, listed as 
threatened. Because of the potential presence of Steller sea lions, the 
Navy engaged in a formal consultation with the NMFS Northwest Regional 
Office under Section 7 of the ESA. We also initiated separate 
consultation with our Northwest Regional Office because of our proposal 
to authorize the incidental take of Steller sea lions. The Biological 
Opinion associated with that consultation concluded that the proposed 
action is not likely to jeopardize the continued existence of the 
Steller sea lion or the humpback whale, and includes an Incidental Take 
Statement for the Steller sea lion. The Steller sea lion does not have 
critical habitat in the action area.

National Environmental Policy Act (NEPA)

    The Navy has prepared an Environmental Impact Statement and issued 
a Record of Decision for this project. We acted as a cooperating agency 
in the preparation of that document, and have reviewed the EIS and the 
public comments received and determined that preparation of any 
additional NEPA analysis is not necessary. We subsequently adopted the 
Navy's EIS and issued our own Record of Decision. The Navy EIS is 
available for public review at www.nbkeis.com.

Authorization

    As a result of these determinations, we have issued an IHA to the 
Navy to conduct the described activities in the Hood Canal from the 
period of July 16, 2012, through February 15, 2013, provided the 
previously described mitigation, monitoring, and reporting requirements 
are incorporated.

    Dated: July 11, 2012.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2012-17488 Filed 7-17-12; 8:45 am]
BILLING CODE 3510-22-P