Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to a Test Pile Program, 38361-38370 [2011-16515]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 76, Number 126 (Thursday, June 30, 2011)]
[Notices]
[Pages 38361-38370]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-16515]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA280


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

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

ACTION: Notice; issuance of an incidental harassment authorization.

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[[Page 38362]]

SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that NMFS has issued an Incidental Harassment Authorization (IHA) to 
the U.S. Navy (Navy) to incidentally harass, by Level B harassment 
only, five species of marine mammals during pile driving activities 
conducted as part of a test pile program in the Hood Canal, Washington.

DATES: This authorization is effective from July 16, 2011, through 
October 31, 2011.

ADDRESSES: A copy of the IHA and application are available by writing 
to Michael Payne, Chief, Permits, Conservation and Education Division, 
Office of Protected Resources, National Marine Fisheries Service, 1315 
East-West Highway, Silver Spring, MD 20910.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the above address, 
telephoning the contact listed here (see FOR FURTHER INFORMATION 
CONTACT) or visiting the internet at: https://www.nmfs.noaa.gov/pr/permits/incidental.htm#applications. Supplemental documents, including 
the Navy's Environmental Assessment and NMFS' associated Finding of No 
Significant Impact, prepared pursuant to the National Environmental 
Policy Act (NEPA), are available at the same site. Documents cited in 
this notice may be viewed, by appointment, during regular business 
hours, at the aforementioned address.

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

SUPPLEMENTARY INFORMATION: 

Background

    Section 101(a)(5)(D) of the MMPA (16 U.S.C. 1371(a)(5)(D)) directs 
the Secretary of Commerce to authorize, upon request, the incidental, 
but not intentional, taking by harassment of small numbers of marine 
mammals of a species or population stock, by United States citizens who 
engage in a specified activity (other than commercial fishing) within a 
specified geographical region if certain findings are made and a notice 
of a proposed authorization is provided to the public for review.
    Authorization for incidental taking of small numbers of marine 
mammals shall be granted if NMFS finds that the taking will have a 
negligible impact on the species or stock(s), and will not have an 
unmitigable adverse impact on the availability of the species or 
stock(s) for subsistence uses (where relevant). The authorization must 
set forth the permissible methods of taking, other means of effecting 
the least practicable adverse impact on the species or stock and its 
habitat, and monitoring and reporting of such takings. 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 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 small numbers of marine mammals. Within 45 days of the 
close of the public comment period, NMFS must either issue or deny the 
authorization.
    Except with respect to certain activities not pertinent here, the 
MMPA defines ``harassment'' as:

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

Summary of Request

    NMFS received an application on November 2, 2010, from the Navy 
for the taking of marine mammals incidental to pile driving in 
association with a test pile program in the Hood Canal at Naval Base 
Kitsap in Bangor, Washington (NBKB). Vibratory and impulsive pile 
driving operations associated with the test pile program have the 
potential to affect marine mammals within the waterways adjacent to 
NBKB, and could result in harassment as defined in the MMPA. This 
test pile program will occur between July 16, 2011, and October 31, 
2011. Six species of marine mammals may be present within the waters 
surrounding NBKB: Steller sea lions (Eumetopias jubatus), California 
sea lions (Zalophus californianus), harbor seals (Phoca vitulina), 
killer whales (Orcinus orca), Dall's porpoises (Phocoenoides dalli), 
and harbor porpoises (Phocoena phocoena). These species may occur 
year-round in the Hood Canal, with the exception of the Steller sea 
lion. Steller sea lions are present only from fall to late spring 
(November-June), outside of the project's timeline (July 16-October 
31). Additionally, while the Southern Resident killer whale (listed 
as endangered under the Endangered Species Act [ESA]) is resident to 
the inland waters of Washington and British Columbia, it is not 
found in the Hood Canal and was therefore excluded from further 
analysis. Only the five species which may be present during the 
project's timeline may be exposed to sound pressure levels 
associated with vibratory and impulsive pile driving, and were 
analyzed in detail in NMFS' analysis of this action.

Description of the Specified Activity

    In accordance with regulations implementing the MMPA, NMFS 
published notice of the proposed IHA in the Federal Register on 
January 25, 2011 (76 FR 4300). A complete description of the action 
was included in that notice and will not be reproduced here.
    NBKB is located on the Hood Canal approximately 20 miles (32 km) 
west of Seattle, Washington, and provides berthing and support 
services to Navy submarines and other fleet assets. The Navy will 
install and remove up to 29 test and reaction piles, conduct loading 
tests on select piles, and measure in-water sound propagation 
parameters (e.g., transmission loss) during pile installation and 
removal. Geotechnical and sound propagation data collected during 
pile installation and removal will be integrated into the design, 
construction, and environmental planning for the Navy's proposed 
Explosive Handling Wharf (EHW-2)--a separate project in planning 
stages and currently undergoing environmental review. While this 
project is designed to produce information necessary for the 
proposed EHW-2, the collected data will allow a better understanding 
of the characteristics of sound produced by pile driving in Hood 
Canal. This information will be instrumental to better understanding 
the potential impacts of other future projects at the NBKB 
waterfront. In addition, the Navy, in collaboration with NMFS, will 
study the performance of new methods of sound attenuation and will 
investigate the efficacy of soft start techniques as well as of the 
use of sound attenuation devices for vibratory driving. This 
information will be broadly applicable to NMFS' future efforts to 
mitigate impacts to marine mammals, and thus carries value in 
addition to the project's intended purpose.
    The test pile program will require a maximum of forty work days 
for completion. The forty work day duration of the program includes 
the time for the initial pile installations, for performing loading 
tests, and to remove all of the test piles. The test pile program 
will involve driving 18 steel pipe piles, at pre-determined 
locations within the proposed footprint of EHW-2. Some of the 
initial 18 piles will be removed and re-driven as part of lateral 
load and tension tests. A total of 11 piles will be installed to 
perform lateral load and tension load tests. All piles will be 
driven with a vibratory hammer for their initial embedment depths, 
and select piles will be impact driven for their final 10-15 ft (3-
4.6 m) for proofing, which involves driving a pile the last few feet 
into the substrate to determine the load capacity of the pile. Noise 
attenuation measures (i.e., bubble curtain) will be used during most 
impact hammer operations and on two of the vibratory-driven piles. 
Certain piles will undergo unmitigated impact driving in order to 
determine performance of the bubble curtain. This represents a 
change from the action as proposed and is discussed later in this 
document. Hydroacoustic

[[Page 38363]]

monitoring will be performed to assess effectiveness of noise 
attenuation measures.
    The Navy anticipates that an average of two piles will be 
installed and removed per day. For each pile installed, the driving 
time is expected to include no more than 1 hour for vibratory 
driving and 15 minutes for the impact driving portion, with a 
maximum 100 blows executed per day. All piles will be extracted 
using a vibratory hammer. Extraction is anticipated to take 
approximately 30 minutes per pile. Overall, this results in an 
estimated maximum of 2 hours for driving and removal per pile, or 
approximately 4 hours per day. Therefore, while 40 days of total in-
water work time is proposed, only a fraction of the total work time 
will actually be spent on pile driving and removal. Based on these 
estimates, the total pile driving time from vibratory or impact pile 
driving would be less than 15 days (29 piles at an average of two 
per day), although delays may spread pile driving over additional 
days.
    For pile driving activities, the Navy used NMFS-promulgated 
thresholds for assessing pile driving impacts (NMFS 2005b, 2009), 
outlined later in this document. The Navy used recommended spreading 
loss formulas (the practical spreading loss equation for underwater 
sounds and the spherical spreading loss equation for airborne 
sounds) and empirically measured source levels from other 30-72 in. 
(0.8-1.8 m) diameter steel pile driving events to estimate potential 
marine mammal exposures. Predicted exposures are outlined later in 
this document. The calculations predict that no Level A harassments 
would occur associated with pile driving activities, and that 1,187 
Level B harassments may occur during the test pile program from 
underwater sound. No incidents of harassment were predicted from 
airborne sounds associated with pile driving.

Changes to the Proposed Action

    As a result of negotiation with the U.S. Fish and Wildlife 
Service, which has jurisdiction over the ESA-listed marbled 
murrelet, the Navy now has the opportunity to conduct some 
unmitigated impact pile driving (i.e., without use of a sound 
attenuation device) in order to empirically determine the 
performance of sound attenuation devices under local conditions. 
NMFS supports this effort, which will enable more precise 
understanding of device efficacy and ensure that the best-performing 
device will be used in this and other pile driving projects. In 
order for the Navy to confirm that the sound attenuation system is 
functioning properly and achieving the levels of reduction that were 
anticipated, comparative measurements must be taken during the 
course of pile driving with the sound attenuation device both in 
operation and shut off.
    Unmitigated driving will be limited to no more than seven piles 
in total, with maximums of one pile per day and 60 seconds per pile. 
The Navy's application provided modeled distances to buffer (Level B 
harassment) and exclusion (Level A harassment or injury) zones, for 
both mitigated and unmitigated driving. The exclusion zone for 
pinnipeds (190-dB) would increase from 5 to 22 m when the sound 
attenuation device is off. The injury zone for cetaceans (180-dB) 
would increase from 22 to 100 m with the device off. The behavioral 
disturbance zone for all marine mammals (160-dB) would increase from 
464 to 2,154 m when the sound attenuation system is off. Using the 
methodology described in NMFS' notice of proposed IHA (76 FR 4300; 
January 25, 2011), the calculated acoustic zones of influence would 
change slightly, as shown in Table 1.

  Table 1--Area Encompassed by Underwater Sound Thresholds for Impact Pile Driving, Mitigated and Unmitigated.
----------------------------------------------------------------------------------------------------------------
                                                                 Area (km\2\) encompassed by threshold
                                                     -----------------------------------------------------------
                     Description                       Pinniped injury--   Cetacean injury--
                                                            190 dB              180 dB          Level B--160 dB
----------------------------------------------------------------------------------------------------------------
Impact driving, no mitigation.......................               0.002               0.031             5.80\1\
Impact driving with bubble curtain, assuming 10 dB                 0.000               0.002            0.509\1\
 attenuation........................................
----------------------------------------------------------------------------------------------------------------
\1\ These areas are smaller than calculated values because the morphology of the shoreline and intervening land
  masses constrain the propagation of sound, resulting in a reduced area of acoustic influence.

    The initial analysis predicted that no injuries would occur, and 
the increased areas of influence do not change that prediction, 
using methodology described in the notice of proposed IHA. However, 
the increase in the size of the behavioral disturbance zone could 
result in additional exposures of animals to underwater sound, and 
thus additional takes under the MMPA. Because only sixty seconds of 
unmitigated driving may occur, for a maximum of seven days, the 
additional impact will be slight. The Navy's initial calculation of 
take estimate conservatively considered a pile driving day to be 
eight hours long. Dividing the potential number of takes that may 
occur per day by the number of minutes in a pile driving day (i.e., 
480 minutes) allows estimation of a per minute take ratio. NMFS 
conservatively rounded any value above 0.01 (i.e., greater than a 1-
percent chance of take occurring in a minute) up to one. The total 
number of takes is equivalent to the number of takes previously 
estimated for fifteen days of attenuated pile driving, plus any 
takes predicted to result per minute of unattenuated pile driving. 
This method predicts an additional seven takes by Level B harassment 
for harbor seals--the species present in the highest density--but 
does not predict additional take of any kind for the other species 
present. This change in estimated take is reflected in the section 
``Estimated Takes by Incidental Harassment.''

Errata

    In NMFS' notice of proposed IHA (76 FR 4300; January 25, 2011), 
Table 10 (``Number of Potential Warm Season (May-Oct) Exposures of 
Marine Mammals within Various Acoustic Threshold Zones'') contained 
a transcription error. Total numbers in the bottom row of that table 
were each shifted one cell to the left. For example, total takes 
should have been depicted as 1,180.

Comments and Responses

    On January 25, 2011, NMFS published notice of proposed IHA (76 
FR 4300) in response to the Navy's request to take marine mammals 
incidental to a test pile program and requested comments and 
information concerning that request. During the 30-day public 
comment period, NMFS received comments from eighteen private 
individuals, the Ground Zero Center for Nonviolent Action (GZCNA), 
the Washington State Department of Natural Resources (DNR), and the 
Marine Mammal Commission (MMC). Seventeen individuals and the GZCNA 
expressed opposition to the proposed action, while one individual 
expressed concern and provided information and recommendations. 
Those expressing opposition did so on the grounds of general 
concerns related to the environment, defense spending, military 
policy, and international treaty issues. In addition, the majority 
of individuals expressed concern over the appropriateness of the 
Navy's NEPA process, stating that the test pile program and the 
proposed EHW-2 construction are connected and should be considered 
together in the same NEPA analysis. It is important to note that 
NMFS' request for comments and information was limited to the 
proposed authorization of marine mammal take incidental to the 
proposed action. NMFS' sole jurisdiction with regard to the MMPA and 
the proposed action is the potential incidental take of marine 
mammals; NMFS has no jurisdiction to approve or deny the proposed 
action itself or over the manner in which the Navy fulfills its 
responsibilities under NEPA. The Navy has chosen to request 
authorization for the test pile program as a standalone action and 
NMFS is required to accept the request to analyze the action. NMFS 
conducted appropriate analysis of the potential for cumulative 
impacts related to the test pile program under NEPA.
    As such, the majority of public comment received concerns 
matters that are outside of

[[Page 38364]]

NMFS' jurisdiction under the MMPA and will not be addressed further. 
The DNR requested that information about results from monitoring of 
the test pile program be shared and raised a concern over use of 
state-owned aquatic lands. These concerns are outside of NMFS' 
jurisdiction and DNR was referred to the Navy. The remaining 
comments and NMFS' responses are detailed below.
    Comment 1: The MMC recommends that NMFS require the Navy to make 
careful observations in conjunction with in-air sound propagation 
information in order to add to the limited data available so that in 
the future thresholds for harassment due to airborne sound can be 
set based on more robust data.
    Response: NMFS agrees with the MMC about the importance of 
founding thresholds for behavioral harassment from airborne sound 
upon the best scientific information available, and about the 
importance of collecting additional data to improve that 
information. As described in the notice of proposed IHA, the Navy 
will be required to collect information regarding observed marine 
mammal behavioral responses to project activities, and if possible, 
the correlation to sound pressure levels. This information will be 
included in the Navy's monitoring report after completion of the 
test pile program.
    Comment 2: The MMC recommends that NMFS require the Navy to 
provide a full description of the survey methods used during 
shoreline surveys at NBKB, including how the Navy searched for 
animals, if and how it corrected its estimate for sighting 
probability, and if and how it corrected its estimate for decreasing 
sighting probability with distance from the observer.
    Response: The Navy has conducted two types of shoreline surveys 
at NBKB. The first set, which generated data used by the Navy in 
calculating density for California sea lions, are opportunistic 
visual area scans for marine mammals conducted by NBKB personnel 
from land at the NBKB waterfront. Sightings of marine mammals at 
manmade haul-out locations (e.g., piers) along the NBKB waterfront 
and in waters adjoining these locations are recorded. NBKB personnel 
attempt to conduct these surveys daily during a typical work week 
(i.e., Monday-Friday), although inclement weather or security 
constraints sometimes preclude surveying. Due to these constraints, 
the number of surveys conducted each month varies. During July-
October (the period of the test pile program), surveys have been 
conducted an average of 13 times per month. Data recorded during 
these scans include species, behavior, associated habitat, and 
weather, among other descriptive information. The majority of all 
sightings are of hauled-out individuals.
    No correction factor for sighting probability of California sea 
lions was used because there is no existing data to support it. The 
availability of a published study in which the movement of tagged 
animals was used in conjunction with aerial surveys allowed the Navy 
to use such a correction factor for harbor seals. The Navy did not 
correct for decreasing detection probability with distance because 
it would be atypical to do so for shoreline pinniped surveys. 
Correcting for decreasing sighting probability with distance is 
appropriate for at-sea surveys, typically targeted towards 
cetaceans. In addition, no information that could potentially 
support such a correction was collected during the surveys. Each 
shoreline and wharf location is at a different height above the 
surface; therefore, the distance surveyed offshore is different at 
each position, which would result in deviations in detection 
probability rather than a constant value. However, the area surveyed 
of nearshore waters adjoining manmade haul-out locations is 
generally contained within the Waterfront Restricted Area (WRA), 
which extends approximately 500-1000 m offshore, and is generally 
able to be clearly observed.
    The second set of shoreline surveys conducted by the Navy, which 
generated data used by the Navy in calculating density for Dall's 
porpoise and harbor porpoise, were defined line transect surveys. 
Marine mammal surveys were conducted from a small vessel operating 
at a speed of approximately five knots. Surveys involved following 
pre-determined transects parallel to the shoreline along the 3.5-mi 
waterfront. Transects were run from shallow water to deeper water 
with the first transect in each area located approximately 300 ft 
(91 m) offshore. Additional parallel transects were located at 300-
ft intervals out to 1,800 ft (549 m) from shore. During these 
surveys, the distance surveyed offshore generally encompassed the 
area out to the WRA, resulting in a total area of 3.9 km\2\ for each 
survey. Two observers and a vessel operator performed the surveys. 
Observers were trained in identification of marine mammal species 
and behavior, distance estimation, and area scanning techniques in 
order to reduce observer variation and avoid missed detections.
    While on transect, the two observers scanned from zero degrees 
off the bow to 90 degrees abeam on each side of the vessel. 
Observers scanned ahead of the vessel for diving mammals and 
communicated any wildlife detections to the other observer to 
minimize missed detections and avoid duplicate observations. 
Observers scanned continuously, not staring in one direction, with a 
complete scan taking about 4-8 seconds. An observer focusing beyond 
100 m is likely to miss some animals that are closer; thus, 
observers varied their focus from near to far fields in scanning 
within the 90-degree arc on each side of the vessel, and used 
binoculars only for species identification but not for sighting 
animals. To maintain effective transect width, animals detected 
through binoculars that would not otherwise have been detected with 
the naked eye were recorded in the comments field of the data form 
as being off transect. For all detections, time stamps were 
generated and locations recorded with a GPS. In addition, the 
observers recorded a compass bearing and distance to each animal or 
group of animals at the point of first detection. Distances were 
measured with a laser rangefinder when possible. Number and species 
of animals and behavior at first sighting were recorded.
    Comment 3: The MMC recommends that NMFS require the Navy to (1) 
explain why it used the anticipated area of ensonification rather 
than surveyed area to estimate sea lion density and (2) correct the 
density estimate unless the Navy has a reasoned basis for not making 
such corrections.
    Response: The data employed in deriving a density estimate for 
California sea lions comes from the first set of surveys (shoreline 
surveys) described previously. NMFS has determined that these 
surveys provide the best available data for determining sea lion 
density. The other available dataset (defined line transect surveys) 
included only sixteen survey days in 2007-2008 during the time 
period in which the test pile program will occur (July-October); 
only six sightings of California sea lions were recorded during 
these sixteen survey days. Two sightings were of individuals 
swimming, and the other four sightings were of groups of hauled-out 
animals. All observations of California sea lions during these 
surveys were over a mile away from the test pile location.
    Although the first dataset is limited in not having a defined 
survey area, as exists for the second dataset, the first dataset 
provides several years of data with many more data points for the 
months in which the test pile program is scheduled to occur and is 
thus the more robust source of data for estimating density of 
California sea lions. As described previously, the shoreline surveys 
averaged 13 survey days per month during July-October of 2008-2009, 
thus providing 104 data points compared with 16 for the line 
transect surveys. In addition, use of this more robust dataset 
results in a more conservative estimate for California sea lion 
density. The Navy also investigated published studies external to 
survey efforts at NBKB. Ideally, aerial surveys encompassing the 
local population's entire geographic range, used in conjunction with 
a correction factor for sighting probability, would be available, as 
was the case for harbor seals. However, this data is not available 
for California sea lions in Hood Canal.
    Because these surveys are of known manmade haul-out areas and 
adjoining waters, and are conducted from land, there is no 
appropriate way to define an area surveyed. It would not be 
appropriate to define survey area strictly as the area observed 
(i.e., the WRA) because the vast majority of sighted animals are 
hauled-out. At haul-outs, animals that forage over some greater 
area--unknown in this case--congregate in greater numbers than would 
be found in the absence of the availability of such habitat. Thus, a 
density calculated for animals found at known haul-outs and 
adjoining waters would not be applicable to the broader marine 
waters of the action area and would result in a gross exaggeration 
of sea lion numbers if extrapolated to that larger area.
    Because all of the California sea lion observations were of 
hauled-out individuals, which gives a reasonable proxy understanding 
of the numbers of animals that are utilizing waters in the vicinity 
of the project area for foraging, a reasonable method of generating 
a realistic in-water density would be to determine the approximate 
area that might be used by the animals when swimming and/or 
foraging. However,

[[Page 38365]]

minimal data is available regarding the foraging home ranges of 
California sea lions. Research by Costa et al. (2007) regarding the 
foraging behavior of 32 adult females in California indicated that 
they travel an average distance of 66.3 +/- 11 km from rookeries. 
Data from Wright et al. (2010) for 14 wintering males from the 
Columbia River indicate that travel is a maximum of 70 km from 
shore. Additional data for 12 adult males from mixed stocks in 
Washington showed a maximum travel distance of 99 km per day (Wright 
et al., 2010). Given these data regarding California sea lion travel 
during foraging trips, NMFS feels that using the maximum action 
area--the largest area affected by underwater sound produced by the 
action (i.e., 41.5 km\2\)--as proposed by the Navy is an acceptable 
representation of the area in which these animals may be expected to 
forage in Hood Canal.
    In a previous environmental analysis for Dabob Bay, located in 
Hood Canal to the south of the action area, the Navy used published 
data (Jeffries et al., 2000) to produce a density estimate of 0.052 
animals/km\2\. While that was likely an underestimate, the density 
estimate produced by the methodology described here (0.410 animals/
km\2\) is significantly higher, and thus more conservative. The 
density estimate is conservative in part because the Navy used the 
highest recorded daily values for each month in the dataset to 
estimate density. For example, in September 2009, the Navy used the 
highest recorded value of 32 animals; the daily average for twelve 
surveys conducted that month was 6.75 animals. In addition, 
California sea lions are generally not present in the action area 
during July-August (one observed sea lion in 51 survey days during 
July-August 2008-2009). While take was estimated for the test pile 
project as though pile driving was equally likely to occur from 
July-October, it is possible that only 15 days may be required. 
Although this is an optimistic scenario (two piles per day for 29 
total piles), and delays may occur that would spread driving out 
over more total days, it is probable that the bulk of pile driving 
will be concluded while there are few California sea lions present.
    NMFS concedes that the data used, and the methodology used in 
estimating density, are not ideal. However, as described here, the 
data used is the best available, and the method of estimating 
density is the most appropriate based on available information. The 
density estimate is also likely conservative, as described 
previously. Finally, no better information or alternative method of 
estimating density was provided or proposed to NMFS during the 
public comment period.
    Comment 4: The MMC recommends that NMFS require the Navy to re-
estimate the expected number of in-water and in-air takes for harbor 
seals using the overall density of harbor seals in Hood Canal (i.e., 
3.74 animals/km\2\).
    Response: As described in NMFS' notice of proposed IHA, the 
entire population of harbor seals in Hood Canal is estimated at 
1,088 (Jeffries et al., 2003). Using this estimate, with the entire 
area of Hood Canal (291 km\2\), produces a density estimate of 3.74 
animals/km\2\. These data represent comprehensive, dedicated aerial 
surveys that were conducted for harbor seals hauled out in the Hood 
Canal by the Washington State Department of Fish and Wildlife from 
1978-1999. However, the work by Jeffries et al. (2003) used a 
correction factor of 1.53, based on VHF-tagging data (Huber et al., 
2001), to account for seals in the water and not counted. The tagged 
animals were from the same populations that were surveyed aerially. 
The data from Huber et al. (2001) indicated that approximately 65 
percent of harbor seals are hauled-out at a given moment (i.e., only 
35 percent of seals are in the water at a given moment). The data 
loggers in these studies ran 24 hours per day. These studies 
computed the average proportion ashore for all seals in the 
population assuming an annual basis; therefore, the data indicates 
that the percentage of harbor seals that can be in the water at any 
one time (35 percent) is assumed to be reasonably consistent on a 
daily basis for the entire year. As a result, exposures to 
underwater sound were calculated using a density derived from the 
number of harbor seals that are anticipated to be present in the 
water at any one time (35 percent of 1,088, or approximately 381 
animals; 1.31 animals/km\2\).
    There are a number of caveats associated with use of this data. 
The cited studies involved aerial surveys that were conducted 
primarily at low-tide, when maximum numbers of seals were hauled-
out. However, the correction factor applied to determine the total 
population and take into account in-water harbor seals was not based 
on the aerial surveys but on VHF tag data which is unaffected by 
tidal influences. While some of the aerial surveys were conducted in 
Hood Canal, Huber et al.'s (2001) tagging data came from outside 
Hood Canal. The VHF data came from radio tags deployed in three 
sites within the coastal stock and three sites within the inland 
waters stock to determine any regional haul-out variability. While 
Hood Canal was not specifically sampled in Huber et al.'s (2001) 
study, Jeffries et al. (2003)--Huber was an author on this study as 
well--found the VHF data broadly applicable to all inland water 
stocks and applied it to estimate the total population for the 
inland waters. While it is possible that proportions of harbor seals 
in the water versus on land in Hood Canal could deviate slightly 
from other inland water stock populations, it is unlikely that such 
deviation would be large. No similar site specific data exists for 
Hood Canal. Therefore, the data described here is considered the 
best available.
    It is possible that the density estimate used for estimating 
take may be an underestimate. Pile driving is estimated as occurring 
a maximum of 4 hours per day, and it is reasonable to expect that 
greater than 35 percent of the individuals in the action area would 
enter the water during the estimated 4-hour duration of pile 
driving. That is, assuming 65 percent of animals are hauled-out at a 
given time, it is possible that some animals may enter and exit the 
water during those 4 hours. Thus, while it is possible that no more 
than 35 percent of animals will be in the water at any given moment 
during pile driving, it is also possible that more than 35 percent 
could potentially be exposed to underwater sound from pile driving 
during those four hours. However, no data exists 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 is no existing data that would 
indicate that the proportion of individuals entering the water 
during pile driving would be dramatically larger than 35 percent; 
thus, the MMC'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 a 
density derived from 35 percent of the population may not result in 
an underestimate of take. Hauled-out harbor seals are necessarily at 
haul-outs, and no 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 2007-2008, 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 would not 
automatically be exposed to underwater sound; rather, only those 
animals embarking on foraging trips and entering the action area may 
be exposed. Moreover, because the Navy is be 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. If the estimated take is an underestimate 
(i.e., if authorized take is exceeded), there is the possibility 
that the Navy's action may need to be halted. Lastly, no alternative 
information or methodology was presented or proposed during the 
public comment period that would lead NMFS to believe that the MMC's 
recommendation would not lead to a gross exaggeration of potential 
take, or that would present a better estimate than that contained 
herein.
    Comment 5: Because the Navy did not request authorization for 
take of harbor seals resulting from exposure to airborne sound, the 
MMC recommends that NMFS require the Navy to shut down activities 
whenever a harbor seal is within the in-air Level B harassment zone 
(i.e., within a radius of 358 m).
    Response: The Navy's waterfront surveys have found that it is 
extremely rare for harbor seals to haul out in the vicinity of the 
test

[[Page 38366]]

pile project area. While in-water sightings are fairly common, even 
temporary, opportunistic haul-out locations are limited within the 
acoustic zone of influence for airborne sound (maximum of 358 m) 
estimated for the test pile program. Harbor seal haul-out area can 
include intertidal or sub-tidal rock outcrops, sandbars, sandy 
beaches, peat banks in salt marshes, and manmade structures such as 
log booms, docks, and recreational floats. The lack of any of these 
suitable haul-out habitats in the immediate vicinity of the test 
pile project area makes it extremely unlikely that a harbor seal 
would be hauled out in range of sounds that could cause acoustic 
disturbance. The only structures within the largest airborne zone of 
influence (358 m) are the current Explosive Handling Wharf (EHW-1) 
and Marginal Wharf. Both of these structures are elevated more than 
sixteen feet above the Mean Higher High Water (MHHW) mark, so there 
is no opportunity for harbor seals to haul out on these structures, 
even during the highest tides. Secondly, while a small intertidal/
shoreline zone is present between these structures, it does not 
represent favorable haul-out habitat for the harbor seal. The 
shoreline located between the current EHW-1 and Marginal Wharf is 
extremely narrow, and is backed by a steep cliff face that is 
heavily vegetated with trees. Additionally, any portion of the 
intertidal zone that may be exposed at low tide is also vegetated 
with eelgrass beds and macroalgae, neither of which is known haul-
out attractant for harbor seals. All harbor seals that are found 
swimming or diving within 358 m of the pile location would be 
considered to be taken by underwater sounds from pile driving 
activities; thus, there is no additional need to shutdown any time a 
harbor seal is within the airborne Level B harassment zone.
    Comment 6: The MMC recommends that NMFS encourage the Navy to 
consult with experts at the National Marine Mammal Laboratory to 
review and revise the Navy's survey methods as needed to make them 
scientifically sound.
    Response: The Navy has consulted with marine science experts in 
the past in the development of surveys and will continue to do so, 
including outreach with the National Marine Mammal Laboratory. NMFS 
is supportive of the Navy's effort to improve the strength of their 
survey design.
    Comment 7: The MMC recommends that NMFS require the Navy to 
record distances to and behavioral observations of animals sighted 
within the entirety of the in-water Level B harassment zone that 
would be established for vibratory pile driving and removal 
activities.
    Response: All shutdown and buffer zones will initially be based 
on predicted distances from the source, as described in the Navy's 
application. The size of the shutdown and buffer zones will be 
adjusted accordingly based on in-situ empirically measured received 
sound pressure levels. The 120-dB disturbance criterion for 
vibratory pile driving predicts an affected area of 41.5 km \2\. Due 
to financial and personnel constraints, it is impracticable to 
effectively monitor such a large area. However, the 120-dB zone will 
be adjusted as necessary based on the results of in-situ 
hydroacoustic monitoring, and it is possible that the true 120-dB 
zone may be of a size that is practicable to monitor. Nevertheless, 
the Navy has committed to monitoring a minimum zone of 2,400 m, 
which corresponds to the width of the Hood Canal at the project 
site. This distance subsumes the next largest buffer zone (the 464 
m, 160-dB Level B disturbance zone for underwater sound from impact 
pile driving). Observers will also be placed in additional locations 
within the 41.5 km \2\ vibratory disturbance zone, as indicated in 
the Navy's Marine Mammal Monitoring Plan. Sightings occurring in the 
area outside of the 2,400 m zone--the maximum zone in which it is 
practicable to effectively monitor--will still be recorded and noted 
as a take. However, it would not be possible to state with certainty 
that all takes were recorded, and fine-scale behavioral observations 
may not be possible. In addition, the proposed monitoring 
methodology is consistent with other actions analyzed by NMFS that 
involve prohibitively large harassment zones. These include seismic 
air gun and sonar activities, in which visual monitoring is only 
practicable for an exclusion zone corresponding to the injury 
thresholds and precise quantification of impacts to marine mammals 
within the behavioral harassment zones could not be empirically 
verified through visual observation, but was estimated by modeling.
    Comment 8: The MMC recommends that NMFS complete an analysis of 
the impact of the proposed activities together with the cumulative 
impacts of all the other pertinent risk factors affecting marine 
mammals in the Hood Canal area, including the Navy's concurrent 
wharf repair project, before issuing the authorization.
    Response: The test pile program and the EHW-1 pile replacement 
project overlap somewhat spatially and temporally. Spatially, the 
two areas are located adjacent to one another. There could be an 
overlap in their buffer zones (Level B harassment zones) but not for 
their exclusion zones (Level A harassment or injury zones) when the 
test piles closest to EHW-1 are installed and removed. Temporal 
overlap will occur as both projects will operate with a work window 
from July 16 through October 31. However, for the test pile program 
impact pile driving will cease no later than October 14, and for 
EHW-1 impact pile driving will cease no later than September 30.
    The injury zones are not large enough to overlap spatially, and 
the Navy has agreed that no simultaneous impact driving will occur, 
in order to ensure that the combined energy of two impact rigs 
operating at once would not increase the potential injury zones. 
With regard to impact pile driving, EHW-1 is limited to impact pile 
driving only five piles per in-water work window, with a maximum of 
one pile driven per day and a maximum of 15 minutes of impact 
driving per pile. The test pile program is anticipated to require 
proofing for 18 test piles, although additional impact driving may 
be required should any of the piles fail to reach the necessary 
embedment depth with vibratory driving. Any impact pile driving 
during the test pile program would be limited to 100 strikes or 15 
minutes per day.
    No limitation has been placed upon vibratory pile installation 
and removal, as such limitation would significantly extend the 
length of each project's timeline and would result in a longer 
period of potential exposure for marine mammals in the Hood Canal. 
Vibratory pile drivers produce significantly lower initial sound 
pressure levels than impact hammers and are not known to cause 
injury to marine mammals. The simultaneous use of two vibratory 
drivers with similar sound outputs would likely increase initial 
sound pressure levels by approximately three decibels, thus 
increasing the potential area encompassed by the 120-dB buffer zone 
(Level B harassment zone) from a modeled 100,000 m to 158,489 m, 
using the practical spreading loss model. As described in NMFS' 
notice of proposed IHA, these distances assume a field free of 
obstruction. However, Hood Canal does not represent open water 
conditions, and sound attenuates upon encountering land masses or 
bends in the canal. As a result, neither hypothetical area of 
potential behavioral effects is possible in the project area. The 
actual distances to the 120-dB behavioral disturbance threshold for 
vibratory pile driving will be significantly reduced due to the 
irregular contours of the waterfront, narrowness of the canal, and 
maximum fetch (furthest distance sound waves travel without 
obstruction) at the project area. Based on these factors, the 
concurrent use of vibratory hammers at both project locations will 
not result in any actual increase in the area encompassed by the 
120-dB criteria.
    The Navy and NMFS have considered the potential overlap of these 
projects and the resulting effects that may occur, and have 
addressed these issues in the cumulative impacts analyses contained 
within their respective NEPA documents for these projects.
    Comment 9: One commenter described a release of toxic material 
that occurred in the test pile area in 2000, and suggested that the 
test pile program could cause further contamination of Hood Canal, 
presumably by suspension of toxic sediment into the water column. If 
this occurred, it could result in decreased quality of pinniped 
habitat.
    Response: Existing sediment information from the project area, 
from sampling conducted in 2007, indicates that sediment quality at 
the project site is generally good. Concentrations of a range of 
metals and organic contaminants were at or below the analytical 
detection limits in some cases and were consistently below the 
Sediment Quality Standards established by Washington State.
    Comment 10: One commenter questioned the need for the full 
complement of test piles proposed by the Navy, stating that the 
relevant information could be collected through installation of a 
lesser number of piles or through alternative methods.
    Response: As described in the Navy's application, the test pile 
program will serve to validate the geotechnical explorations used in 
the design to estimate capacities of piles. Estimated pile embedment 
requirements and pile capacities provided by the geotechnical 
engineer without the benefit of site-specific empirical data from 
the test

[[Page 38367]]

pile program are conservative. The program will serve to provide 
such data to verify required embedment lengths and pile capacities. 
Real data can reduce conservatism, providing the potential of 
reduced pile sizes and lengths. The cost of piles can be broken into 
material purchase price and pile installation costs. A reduction of 
overall pile size or length, thus steel quantity, provides benefit 
of reduced costs both with initial price of material purchase and 
installation costs. Additionally, pile size or length reductions can 
reduce the amount of time the pile driving rigs are on site, 
reducing pile installation costs and impacts to the environment. The 
program will also establish the ability to advance piles to design 
tip using a vibratory hammer. This will potentially limit the 
strikes with an impact hammer to that of proofing piles, resulting 
in both environmental and cost benefits. The Navy has no desire to 
incur unnecessary expenditures, either through installing extraneous 
piles or by using methods inappropriate to gather required data. 
This data is critical to the design and cost planning of an 
explosives handling wharf, and validation of geotechnical and design 
assumptions is critical to long term survivability and safety.
    Comment 11: One commenter challenged several assumptions and 
conclusions made by the Navy related to acoustic impacts. The 
commenter included numerous questions, but three key points related 
to acoustics were: (1) That, while total energy may be important for 
threshold shifts, frequency content is important as well (e.g., for 
masking); (2) that the Navy's use of the practical spreading loss 
model may not be appropriate, instead suggesting a ray path model 
using a salinity/velocity profile; and (3) that an assumption of a 
10-dB reduction in sound intensity through attenuation by bubble 
curtain is unduly optimistic.
    Response: The purpose of the test pile program is, in part, to 
answer many of the questions posed. For example, data from the test 
pile program will show whether the practical spreading loss model is 
appropriate as used (i.e., the appropriate transmission loss 
coefficient will be derived through test pile measurements) and will 
empirically determine the actual performance of sound attenuation 
measures (e.g., bubble curtain). As the commenter points out, 
certain factors (e.g., depth, salinity) are important considerations 
for propagation modeling. Again, measurements from test piles will 
enable empirical determination of sound propagation in this location 
and for this activity. The commenter inquires about the spectrum of 
pulse transmission, which may refer to the distribution of frequency 
in narrow bands across the frequency range. This data will be 
collected during test pile driving.
    With regard to bottom propagation and surface reflection, 
computation for these values by modeling is extremely complex, 
especially in shallow water. However, although use of a simple 
spreading model may not be entirely accurate, it is likely to 
produce a conservative estimate of sound propagation distances 
because it does not take bottom loss into consideration. In 
addition, because pile driving will occur in shallow water, and the 
dominant energy is low frequency, ray theory is unlikely to be the 
most appropriate method of modeling propagation. It is important to 
note that the estimates of buffer and exclusion zones presented 
here, as determined by relatively simple modeling, will be corrected 
as dictated by in-situ empirical measurements. This makes more 
complicated modeling efforts using bottom loss and surface 
reflection values unnecessary. Finally, while NMFS concedes that it 
is extremely difficult to accurately predict site-specific 
attenuation performance (specifically by bubble curtains) due to the 
number of variables at play, the estimate of 10 dB is not 
necessarily overly optimistic--it falls below the midpoint of 
attenuation variability described by Thorson and Reyff (2004)--and 
will likely be effective at reducing peak pressure characteristics 
of impact strikes regardless of total attenuation. Calculated buffer 
and exclusion zones will be adjusted in the field as appropriate 
based not only on empirically measured sound propagation, but also 
on actual performance of sound attenuation measures.

Description of Marine Mammals in the Area of the Specified Activity

    The marine mammal species that may be harassed incidental to 
estuary management activities are the harbor seal, California sea 
lion, killer whale, Dall's porpoise, and harbor porpoise. None of 
these species are listed as threatened or endangered under the ESA, 
nor are they categorized as depleted under the MMPA. NMFS presented 
a more detailed discussion of the status of these stocks and their 
occurrence in the action area in the notice of the proposed IHA (76 
FR 4300; January 25, 2011).

Potential Effects of the Activity on Marine Mammals

    NMFS has determined that pile driving, as outlined in the 
project description, has the potential to result in behavioral 
harassment of California sea lions, harbor seals, harbor porpoises, 
Dall's porpoises, and killer whales that may be swimming, foraging, 
or resting in the project vicinity while pile driving is being 
conducted. Pile driving could potentially harass those pinnipeds 
that are in the waters adjoining the project site.
    Based on the analysis contained in NMFS' notice of proposed IHA, 
it is unlikely that this project will result in temporary or 
permanent hearing impairment or non-auditory physical or 
physiological effects for any marine mammal. Because this project 
involves driving a small number of piles, with limited use of an 
impact driver, and will occur in a small area for limited duration, 
effects to marine mammals are likely to be limited to behavioral 
harassment. The planned mitigation measures for this project (see 
the ``Mitigation'' section later in this document) are designed to 
detect marine mammals occurring near the pile driving to avoid 
exposing them to sound pulses that might, in theory, cause hearing 
impairment. In addition, many cetaceans are likely to show some 
avoidance of the area where received levels of pile driving sound 
are high enough that hearing impairment could potentially occur. In 
those cases, the avoidance responses of the animals themselves will 
reduce or (most likely) avoid any possibility of hearing impairment.
    The effects of behavioral disturbance resulting from this 
project are difficult to predict, as behavioral responses to sound 
are highly variable and context specific. A number of factors may 
influence an animal's response to noise, including its previous 
experience, its auditory sensitivity, its biological and social 
status (including age and sex), and its behavioral state and 
activity at the time of exposure. These behavioral changes may 
include changes in duration of surfacing and dives or moving 
direction and/or speed; changes in vocalization; visible startle 
response or aggressive behavior; avoidance of areas where noise 
sources are located; and/or flight responses. Pinnipeds may increase 
their haul-out time, possibly to avoid in-water disturbance. Since 
pile driving will likely only occur for a few hours a day, over a 
short period of time, it is unlikely to result in permanent 
displacement from the area. Temporary impacts from pile driving 
activities could be experienced by individual marine mammals, but 
would not be likely to cause population level impacts, or affect any 
individual's long-term fitness.
    The three cetacean species are rare in the project area, and, if 
present, numbers will likely be in single digits. While pinniped 
numbers will likely be greater, there are several factors indicating 
that these animals may only experience minor effects from behavioral 
disturbance. As described previously in this document, California 
sea lions are typically not present in the project area during July-
August, and it is likely that the majority of pile driving will be 
complete before sea lions begin arriving in September. No haul-out 
areas are located in the immediate vicinity of the project site. 
California sea lions haul-out on manmade structures along the NBKB 
waterfront, typically over a mile from the project site. Harbor 
seals, though present in the Hood Canal year-round, have primary 
haul-outs even further away, in Dabob Bay to the west and at points 
further south.

Anticipated Effects on Habitat

    NMFS provided a detailed discussion of the potential effects of 
this action on marine mammal habitat in the notice of the proposed 
IHA (76 FR 4300; January 25, 2011). The pile driving activities at 
NBKB will 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 structure 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 will be temporarily elevated noise 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 marine mammal prey (i.e., fish) 
near NBKB

[[Page 38368]]

and minor impacts to the immediate substrate during installation and 
removal of piles during the test pile program.
    Sound pressure levels of sufficient strength have been known to 
cause injury to fish and fish mortality (CALTRANS 2001; Longmuir and 
Lively 2001). However, due to mitigation measures in place to reduce 
impacts to ESA-listed fish--notably including adherence to the July 
16-October 31 work window--the most likely impact to fish from pile 
driving activities at the project area will be temporary avoidance 
of the area. The duration of fish avoidance of this area after pile 
driving stops is unknown, but a rapid return to normal recruitment, 
distribution and behavior is anticipated. In general, impacts to 
marine mammal prey species are expected to be minor and temporary 
due to the short timeframe for the test pile program.

Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to 
such activity, and other means of effecting the least practicable 
adverse 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.
    The Navy has established exclusion and buffer zones (Level A and 
Level B harassment, respectively), based on modeling described in 
NMFS' notice of proposed IHA (76 FR 4300; January 25, 2011). The 
Navy will implement the following measures for these zones:
    (1) The Navy will implement a minimum shutdown zone of 50 m (164 
ft) radius around all pile driving activity. Shutdown zones 
typically include all areas where the underwater SPLs are 
anticipated to equal or exceed the Level A (injury) harassment 
criteria for marine mammals (180-dB isopleth for cetaceans; 190-dB 
isopleth for pinnipeds). In this case, pile driving sounds are 
expected to attenuate below 180 dB at distances of 22 m or less, but 
the 50-m shutdown is intended to further avoid the risk of direct 
interaction between marine mammals and the equipment.
    (2) The buffer zone shall initially be set at a radius of 2,400 
m, which is the width of the Hood Canal at the project site. This 
zone, which would subsume the 160-dB buffer zone, is the maximum 
area that is practicable for the Navy to monitor. The full 120-dB 
buffer zone for vibratory pile driving (modeled as radius of 13,800 
m, but reduced to 41.5 km \2\ when attenuation due to landmasses is 
accounted for) is so large as to make monitoring impracticable. 
Additional observers will be present in this zone, and any sighted 
animals would be recorded as takes, but it is impossible to 
guarantee that all animals will be observed or to make observations 
of fine-scale behavioral reactions to sound throughout this zone. 
The 2,400 m (1,644 ft) zone may be adjusted according to empirical, 
site-specific data after the project begins. Additional buffer zone 
distances, including the 160-dB zone for underwater sound from 
impact driving (464 m), may also be adjusted based upon the results 
of hydroacoustic monitoring.
    (3) The shutdown and buffer zones will be monitored throughout 
the time required to drive a pile. If a marine mammal is observed 
entering the buffer zone, a take will be recorded and behaviors 
documented. However, that pile segment will be completed without 
cessation, unless the animal approaches or enters the shutdown zone, 
at which point all pile driving activities will be halted.
    (4) All buffer and shutdown zones will initially be based on the 
distances from the source that are predicted for each threshold 
level. However, in-situ acoustic monitoring will be utilized to 
determine the actual distances to these threshold zones, and the 
size of the shutdown and buffer zones will be adjusted accordingly 
based on received sound pressure levels.
    Monitoring will take place from thirty minutes prior to 
initiation through thirty minutes post-completion of pile driving 
activities. The following additional measures will apply to visual 
monitoring:
    (1) Monitoring will be conducted by qualified observers. A 
trained observer will be placed from the best vantage point(s) 
practicable to monitor for marine mammals and implement shut-down or 
delay procedures when applicable by calling for the shut-down to the 
hammer operator.
    (2) Prior to the start of pile driving activity, the shutdown 
and safety zones will be monitored for thirty minutes to ensure that 
they are 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 buffer zone (i.e., 
must leave of their own volition) and their behavior will be 
monitored and documented.
    (3) If a marine mammal approaches or enters the shutdown zone 
during the course of pile driving operations, pile driving will be 
halted and delayed until either the animal has voluntarily left and 
been visually confirmed beyond the shutdown zone or thirty minutes 
have passed without re-detection of the animal.
    The following additional measures will be implemented:
    (1) Sound attenuation devices will be utilized during most 
impact pile driving operations (exceptions described previously in 
this document).
    (2) The Navy will use soft-start techniques (ramp-up and dry 
fire) recommended by NMFS for impact and vibratory pile driving. The 
soft-start requires contractors to initiate noise from vibratory 
hammers for fifteen seconds at reduced energy followed by a one 
minute waiting period. This procedure will be 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 1-minute waiting period, then two 
subsequent three strike sets.
    (3) Pile driving will only be conducted during daylight hours.
    (4) For in-water heavy machinery work other than pile driving, 
if a marine mammal comes within 50 m (164 ft), operations shall 
cease and vessels shall reduce speed to the minimum level required 
to maintain steerage and safe working conditions.
    NMFS has carefully evaluated the applicant's mitigation measures 
as proposed and considered their effectiveness in past 
implementation to determine whether they are likely to effect the 
least practicable adverse impact on the affected marine mammal 
species and stocks and their habitat. Our evaluation of potential 
measures includes 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; (3) 
the practicability of the measure for applicant implementation, 
including consideration of personnel safety, and practicality of 
implementation.
    It is unlikely that injury, serious injury, or mortality to 
marine mammals would result from any actions undertaken during the 
test pile program. The impacts of the project will likely be limited 
to temporary behavioral disturbance. However, to reduce the amount 
and degree of behavioral disturbance that occurs, NMFS and the Navy 
have developed the previously described mitigation measures. These 
are designed to limit the numbers of marine mammals that are exposed 
to underwater sound, by reducing the intensity of sound entering the 
environment, limiting the amount of impact pile driving and the 
duration of all driving, and to prevent any individual from being 
exposed to levels of sound that could result in injury. Based upon 
experience from previous pile driving projects and the analysis 
contained in NMFS' notice of proposed IHA and in this document, NMFS 
has determined that the proposed mitigation measures provide the 
means of effecting the least practicable adverse impacts on marine 
mammal species or stocks and their habitat.

Monitoring and Reporting

    In order to issue an ITA for an activity, section 101(a)(5)(D) 
of the MMPA states that NMFS must set forth ``requirements 
pertaining to the monitoring and reporting of such taking''. The 
MMPA implementing regulations at 50 CFR 216.104 (a)(13) indicate 
that requests for IHAs must include the suggested means of 
accomplishing the necessary monitoring and reporting that will 
result in increased knowledge of the species and of the level of 
taking or impacts o