Small Takes of Marine Mammals Incidental to Specified Activities; Exploratorium Relocation Project in San Francisco, CA, 66065-66070 [2010-27178]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 75, Number 207 (Wednesday, October 27, 2010)]
[Notices]
[Pages 66065-66070]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2010-27178]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XX25


Small Takes of Marine Mammals Incidental to Specified Activities; 
Exploratorium Relocation Project in San Francisco, CA

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

ACTION: Notice; issuance of an incidental take authorization.

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SUMMARY: In accordance with the Marine Mammal Protection Act (MMPA) 
regulations, notification is hereby given that NMFS has issued an 
Incidental Harassment Authorization (IHA) to the Exploratorium, 
allowing the take of small numbers of marine mammals, by Level B 
harassment only, incidental to pile driving associated with the 
Exploratorium's relocation project.

DATES: Effective October 25, 2010, through October 24, 2011.

ADDRESSES: A copy of the IHA, the application, and the Environmental 
Assessment are available by writing to P. Michael Payne, Chief, 
Permits, Conservation and Education Division, Office of Protected 
Resources, National Marine Fisheries Service, 1315 East-West Highway, 
Silver Spring, MD 20910-3225 or by 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. 
Documents cited in this notice may be viewed, by appointment, during 
regular business hours, at the aforementioned address.

FOR FURTHER INFORMATION CONTACT: Michelle Magliocca or Jaclyn Daly, 
Office of Protected Resources, NMFS, 301-713-2289.

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specific 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 
published in the Federal Register and 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 United States 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 publication of notice of the proposal to 
issue an IHA in the Federal Register and a 30-day public comment 
period. 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

    On April 28, 2010, NMFS received an application from the 
Exploratorium--a nature, science, art, and technology museum--
requesting an IHA for the take, by Level B harassment, of small numbers 
of marine mammals incidental to relocation of the Exploratorium museum. 
The Exploratorium is relocating from the Palace of Fine Arts to Piers 
15 and 17, along San Francisco's waterfront, to allow for expansion of 
the museum's facility. Pile driving during the project may result in 
harassment of Pacific harbor seals (Phoca vitulina richardii), 
California sea lions (Zalophus californianus), harbor porpoises 
(Phocoena phocoena), and gray whales (Eschrichtius robustus) within the 
action area. In accordance with MMPA implementing regulations, NMFS 
issued a notice in the Federal Register on July 22, 2010 (75 FR 42691), 
requesting comments from the public on the proposed IHA.

Description of the Specified Activity

    A complete description of the specified activity may be found in 
NMFS' proposed IHA notice in the Federal Register (75 FR 42691, July 
22, 2010) and a summary is provided here.
    To make room for the new Exploratorium, a maximum of 69 various 
sized steel piles (thirty 72-inch, twenty-six 24-inch, and thirteen 20-
inch diameter piles) will be installed around Piers 15 and 17 using a 
vibratory hammer (Table 1). Between two and five steel piles (average 
of three piles) will be installed daily, depending on their size and 
the amount of time necessary to install them. Each pile will take 
approximately 30 minutes to install followed by at least one hour 
break, the minimum amount of time needed to reset the hammer and next 
pile. In total, the Exploratorium anticipates conducting 28 hours of 
pile driving over the course of their authorization; however, this may 
be increased due to encountering difficulty in driving piles, 
construction extensions, etc. All piles will be installed with an ICE 
14122 (or similar) vibratory hammer; however, it may be necessary to 
seat a pile using an impact hammer. Based on the ground sediments and 
the depth of pile driving needed, the use of an impact hammer is not 
anticipated for the smaller 20-inch and 24-inch piles but may be needed 
for the large diameter 72-inch piles. Should an impact hammer be 
necessary, the Exploratorium will use a steam or

[[Page 66066]]

diesel-powered hammer delivering between 80,000 and 110,000 ft-lbs per 
blow. For 20, 24, and 72-inch piles, the amount of strikes per pile 
will be limited to 120, 25, and 5, respectively. A sound attenuation 
device (e.g., wood block, bubble curtain) will be used during all 
impact hammering. In addition, impact hammering will not occur between 
June 1 and November 30 to prevent injury to listed salmonids.
    In addition to pile driving, the Exploratorium will repair or 
remove existing piles (Table 1) and remove existing wharf decking. 
Existing concrete piles will be removed by cutting them with a 
hydraulic shear. The shear operates like a knife gate, with hydraulic 
rams pushing a shear plate through the piling. The cutting shear will 
be suspended from a crane on deck. In-water noise from this work will 
be negligible. Pile repair will include installing a fiberglass shell 
around damaged pile and filling the shell with concrete. The work will 
be completed by divers using hand tools and does not involve loud 
noise. Deck removal and expansion will occur outside of habitat for 
marine mammals. Finally, there will be two to ten barges or floats at 
any given time in the water to support construction activities; 
however, these will be concentrated in the direct vicinity of Piers 15/
17. Because pile repair, pile removal, and use of barges do not release 
loud sounds into the environment, marine mammal harassment from these 
activities is not anticipated.

 Table 1--Summary of Pile Activities During the Exploratorium Relocation
                                Activity
------------------------------------------------------------------------
                                Maximum number of
          Activity                    piles               Location
------------------------------------------------------------------------
Installation of new piles...  69 steel piles (30    Marginal Wharf;
                               72-inch diameter      South Apron.
                               steel piles, 26 24-
                               inch steel piles,
                               and 13 20-inch
                               steel piles).
Repair of existing piles....  1,026...............  Pier 15; Valley
                                                     Infill Area;
                                                     Marginal Wharf;
                                                     North Apron.
Extension of existing piles.  120.................  Valley Infill Area.
Removal of existing piles--   837.................  Marginal Wharf;
 cut at mudline.                                     Valley Removal
                                                     Area; South Apron;
                                                     Pier 15.
Removal of existing piles--   306.................  Valley Removal Area;
 cut above mean lower low                            Marginal Wharf.
 water (MLLW).
------------------------------------------------------------------------

    During the San Francisco-Oakland Bay Bridge Project (SFOBB), the 
California Department of Transportation (Caltrans), measured vibratory 
driving sound levels from various pile types, sizes, and locations 
around San Francisco Bay (Caltrans, 2007). Because no pile driving 
noise data specific to the Exploratorium project exists, NMFS has 
determined that hydroacoustic data from the Caltrans SFOBB project are 
appropriate to use to estimate sound levels from the specified 
activity. For background, sound is a physical phenomenon consisting of 
minute vibrations that travel through a medium, such as air or water, 
and is generally characterized by several variables. Frequency 
describes the sound's pitch and is measured in hertz (Hz) or kilohertz 
(kHz), while sound level describes the sound's loudness and is measured 
in decibels (dB). Sound level increases or decreases exponentially with 
each dB of change. For example, 10 dB yields a sound level 10 times 
more intense than 1 dB, while a 20 dB level equates to 100 times more 
intense, and a 30 dB level is 1,000 times more intense. Sound levels 
are compared to a reference sound pressure (micro-Pascal) to identify 
the medium. For air and water, these reference pressures are ``re: 20 
microPa'' and ``re: 1 microPa,'' respectively. In this document, all 
sound pressure levels (SPLs) will be referenced to 1 microPa unless 
otherwise noted.
    In 2007, Caltrans released a report summarizing typical and maximum 
sound pressure levels (SPLs) measured during vibratory pile driving in 
San Francisco Bay (Table 2). In summary, Caltrans found that SPLs 
measured 5 m from the vibratory hammer did not exceed 180 dB root mean 
square (rms) and were typically around 170 dB rms. Most of the energy 
during vibratory pile driving was below 600 Hz. NMFS notes that the 
vibratory hammers Caltrans used to install the 72-inch pile were the 
King Kong and Super Kong Driver (Model 600). The hammer the 
Exploratorium will be using is 40 percent of the energy of the King 
Kong hammer; therefore, source levels will be lower for the relocation 
project as hammer noise levels are proportional to blow energy. 
Vibratory pile driving measurements taken by Caltrans approximately 11-
13 kilometers (km) northeast of the Exploratorium in similar depth 
water indicate that peak sound pressures drop off at a rate of about 7 
dB per doubling of distance. For comparison, spherical spreading (20 
log R) is characterized by a drop-off rate of 6 dB per doubling of 
distance.


Table 2--Measured Sound Pressure Levels During Vibratory Pile Driving in
                            San Francisco Bay
                            [Caltrans, 2007]
------------------------------------------------------------------------
                                Relative water
        Pile type/size               depth          SPL at 10 m (rms)
------------------------------------------------------------------------
72-inch steel pile...........  5 meters........  Average = 170 dB.
                                                 Loudest = 180 dB.
34-inch steel pile...........  5 meters........  Average = 170 dB.
                                                 Loudest = 175 dB.
24-inch steel pile...........  5 meters........  Average = 160 dB.
                                                 Loudest = 165 dB.
12-inch steel pile...........  5 meters........  Average = 155 dB.
------------------------------------------------------------------------


[[Page 66067]]

    Caltrans also conducted hydroacoustic surveys within San Francisco 
Bay during impact pile driving of similar size piles proposed for use 
by the Exploratorium (Table 3). Bubble curtains can provide between 5-
20 dB reduction in source level; however, this is highly directional 
and a function of current and device effectiveness (Caltrans, 2009). 
Therefore, distances to the Level A and Level B harassment isopleths 
are based on estimated unattenuated source levels. These distances are 
likely an overestimate of sound levels produced by pile driving using a 
bubble curtain or wood cap.


 Table 3--Measured Unattenuated Sound Pressure Levels in the Near Field
         (10 m) During Impact Pile Driving in San Francisco Bay
                            [Caltrans, 2009]
------------------------------------------------------------------------
                                   Relative water
         Pile type/size                depth          SPL at 10 m (rms)
------------------------------------------------------------------------
96-inch steel pile.............  10 meters........               205 dB.
60-inch steel pile.............  <5 meters........               195 dB.
36-inch steel pile.............  <5 meters........               190 dB.
24-inch steel pile.............  5 meters.........               190 dB.
14-inch steel pile.............  15 meters........               184 dB.
------------------------------------------------------------------------

Comments and Responses

    A notice of receipt and request for public comment on the 
application and proposed authorization was published on July 22, 2010 
(75 FR 42691). During the 30-day public comment period, the Marine 
Mammal Commission (Commission) provided the only comments.
    Comment 1: The Commission recommends that NMFS issue the requested 
authorization, provided that observations be made during all soft-
starts of pile driving activities in order to gather the data needed to 
analyze and report on its effectiveness as a mitigation measure.
    Response: NMFS disagrees that the Exploratorium needs to monitor 
for marine mammals during all soft-starts. PSOs will be on-site and 
monitoring for marine mammals at least 30 minutes prior to, during, and 
after all impact hammer (including during soft-starts) and at least two 
full days per week during all vibratory pile hammering. NMFS believes 
that monitoring for at least two pile driving days per week will allow 
for adequate interpretation of how marine mammals are behaving in 
response to pile hammering, including during soft-starts.
    Comment 2: The Commission recommends that NMFS issue the requested 
authorization, provided that the Exploratorium be required to monitor 
the presence and behavior of marine mammals during all impact and 
vibratory pile driving activities.
    Response: As stated in the proposed IHA, marine mammal monitoring 
will occur 30 minutes before, during, and 30 minutes after all impact 
pile driving activities. In addition, at least one PSO will conduct 
behavioral monitoring at least two days per week during vibratory pile 
driving for the duration of the project to estimate take and evaluate 
the behavioral impacts that pile driving has on marine mammals out to 
the Level B harassment isopleth (1,900) m. NMFS believes this is an 
adequate effort of monitoring because vibratory pile driving will not 
produce source SPLs exceeding 180 dB rms (Level A harassment threshold) 
and therefore, the activity will not require shut-down in order to 
prevent Level A harassment. Monitoring by Caltrans is also being 
conducted in the area, and given the limited number of pile driving 
hours and Exploratorium resources, this amount of monitoring is 
expected to be adequate to verify that the specified activity is having 
a negligible impact on the affected species and stocks.

Description of Marine Mammals in the Area of the Specified Activity

    Marine mammals with confirmed occurrences in San Francisco Bay are 
the Pacific harbor seal, California sea lion, harbor porpoise, gray 
whale, humpback whale (Megaptera noveangliae), and sea otter (Enhydra 
lutris). However, humpback whales are considered extremely rare in San 
Francisco Bay and are highly unlikely to be present in the project 
vicinity during pile driving. Sea otters are managed by the U.S. Fish 
and Wildlife Service. Information on Pacific harbor seals, California 
sea lions, harbor porpoises, and gray whales was provided in the July 
22, 2010 (75 FR 42691) Federal Register notice.

Potential Effects on Marine Mammals

    Pile driving at the Exploratorium's new location may temporarily 
impact marine mammal behavior within the action area due to elevated 
in-water noise levels. A detailed description of potential impacts to 
marine mammals can be found in NMFS' July 22, 2010 Federal Register 
notice (75 FR 42691) and are summarized here.
    Marine mammals produce sounds in various contexts and use sound for 
various biological functions including, but not limited to, (1) Social 
interactions; (2) foraging; (3) orientation; and (4) predator 
detection. Interference with producing or receiving these sounds may 
result in adverse impacts. Audible distance, or received levels (RLs) 
will depend on the nature of the sound source, ambient noise 
conditions, and the sensitivity of the receptor to the sound 
(Richardson et al., 1995). Type and significance of marine mammal 
reactions to noise are likely to dependent on a variety of factors 
including, but not limited to, the behavioral state (e.g., feeding, 
traveling, etc.) of the animal at the time it receives the stimulus, 
frequency of the sound, distance from the source, and the level of the 
sound relative to ambient conditions (Southall et al., 2007).

Hearing Impairment

    Temporary or permanent hearing impairment is possible when marine 
mammals are exposed to very loud sounds. Hearing impairment is measured 
in two forms: Temporary threshold shift (TTS) and permanent threshold 
shift (PTS). There are no empirical data for onset of PTS in any marine 
mammal; therefore, PTS-onset must be estimated from TTS-onset 
measurements and from the rate of TTS growth with increasing exposure 
levels above the level eliciting TTS-onset. PTS is presumed to be 
likely if the hearing threshold is reduced by >=40 dB (i.e., 40 dB of 
TTS). Due to proposed mitigation measures and source levels, NMFS does 
not expect that marine mammals will be exposed to levels that could 
elicit PTS.

Temporary Threshold Shift (TTS)

    TTS is the mildest form of hearing impairment that can occur during 
exposure to a loud sound (Kryter, 1985).

[[Page 66068]]

While experiencing TTS, the hearing threshold rises and a sound must be 
louder in order to be heard. TTS can last from minutes or hours to, in 
cases of strong TTS, days. For sound exposures at or somewhat above the 
TTS-onset threshold, hearing sensitivity recovers rapidly after 
exposure to the noise ends. Few data on sound levels and durations 
necessary to elicit mild TTS have been obtained for marine mammals. 
Southall et al. (2007) considers a 6 dB TTS (i.e., baseline thresholds 
are elevated by 6 dB) sufficient to be recognized as an unequivocal 
deviation and thus a sufficient definition of TTS-onset. Because it is 
non-injurious, NMFS considers TTS as Level B harassment that is 
mediated by physiological effects on the auditory system; however, NMFS 
does not consider onset TTS to be the lowest level at which Level B 
harassment may occur.
    Southall et al. (2007) summarizes underwater pinniped TTS data from 
Kastak et al. (2005), indicating that a tested harbor seal showed a TTS 
of around 6 dB when exposed to a nonpulse noise at SPL 152 dB re: 1 
[micro]Pa for 25 minutes. In contrast, a tested sea lion exhibited TTS-
onset at 174 dB re: 1 [micro]Pa under the same conditions as the harbor 
seal. Data from a single study on underwater pulses found no signs of 
TTS-onset in sea lions at exposures up to 183 dB re: 1 [micro]Pa (peak-
to-peak) (Finneran et al., 2003). There is no information on species-
specific TTS for harbor porpoises exposed to non-pulse sound or for 
gray whales. Based on studies summarized in Southall et al. (2007), 
NMFS anticipates that vibratory pile driving will not induce TTS since 
SPLs generated from the activity are low and, contrary to animals 
confined to a tank, animals in the wild will likely not remain in the 
area long enough to be exposed for an extended period of time. 
Similarly, if impact pile driving is required, it will only be 
temporary (5-25 strikes) and will be delayed if animals are seen 
approaching the Level A harassment isopleth. As such, impact pile 
driving is not likely to induce TTS.
    No known data exists for sound levels resulting from the type of 
vibratory hammer and pile sizes that would be used at the 
Exploratorium; however, measured sound levels for the ``King Kong'' 
vibratory hammer used in Richmond, California ranged between 163 and 
180 dB rms (Illingworth and Rodkin, 2007). Sound levels at the 
Exploratorium are expected to be substantially lower because the 
vibratory hammer being used is approximately 40 percent of the 
energetic capacity of the ``King Kong'' hammer and will not be used at 
full capacity. In addition, San Francisco Bay is highly industrialized 
and masking of the pile driver by other vessels and anthropogenic noise 
within the action area may, especially in the nearby shipping channel, 
may also make construction sounds difficult to hear at greater 
distances. Underwater ambient noise levels along the San Francisco 
waterfront may be around 133 dB rms, based on measurements from the 
nearby Oakland Outer Harbor (Caltrans, 2009).
    Any impacts to marine mammal behavior are expected to be temporary. 
First, animals may avoid the area around the hammer; thereby reducing 
exposure. Second, pile driving does not occur continuously throughout 
the day. As described above, the vibratory hammer only operates for 
about 30 minutes followed by at least a one hour break. Two to five 
pilings are anticipated to be driven per day, resulting in a total of 
1-2.5 hours of pile driving within any given 24 hour period. Limiting 
pile driving to less than three hours per day will allow for minimal 
disruption of foraging or dispersal throughout the habitat. Any 
disturbance to marine mammals is likely to be in the form of temporary 
avoidance or alteration of opportunistic foraging behavior near the 
pile driving location. In addition, because pile driving is anticipated 
to be accomplished using only a vibratory hammer, marine mammal injury 
or mortality is not anticipated. If an impact hammer is used, a 
protected species observer (PSO) will be on watch to implement pile 
driver shut down, a mitigation measure designed to prevent animals from 
being exposed to injurious level sounds. For these reasons, any changes 
to marine mammal behavior are expected to be temporary and result in a 
negligible impact to affected species and stocks.

Anticipated Effects on Habitat

    Marine mammal habitat will be temporarily disturbed due to pile 
driving activities. Installation of new piles will be permanent; 
however, overall site conditions are anticipated to be substantively 
unchanged from existing conditions for marine mammals following project 
implementation. NMFS Southwest Regional Office determined that the 
proposed construction activities would adversely affect Essential Fish 
Habitat (EFH); however, adequate measures are in place to avoid, 
minimize, mitigate, or otherwise offset the adverse effects to EFH.

Mitigation Measures

    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 latter does not apply here, as 
no subsistence hunting takes place in California. The following 
summarizes mitigation and monitoring measures set forth in the IHA.

Limited Use of an Impact Hammer

    All piles will be installed using a vibratory pile driver unless 
sufficient depth cannot be reached, at which point an impact hammer may 
be used. In the event that an impact hammer is necessary, a bubble 
curtain, wood block, or both will be used as an attenuation device to 
reduce hydroacoustic sound levels to avoid the potential for injury.

Establishment of a Safety Zone

    For all in-water impact pile driving, the Exploratorium will 
establish a preliminary marine mammal safety zone of 500 m (1,640 ft) 
around each pile before pile driving commences. Once impact pile 
driving commences, the Exploratorium may establish a new safety zone 
where sound levels do not exceed 180 dB rms and 190 dB rms (for 
cetaceans and pinnipeds, respectively) based on acoustical monitoring 
data collected during pile driving. No safety zone for vibratory pile 
driving is necessary, as source levels will not exceed the Level A 
harassment threshold.

Pile Driving Shut Down and Delay Procedures

    If a PSO observes a marine mammal within or approaching the safety 
zone prior to start of impact pile driving, the PSO will notify the 
Resident Engineer (or other authorized individual) who will then be 
required to delay pile driving until the marine mammal has moved 
outside of the safety zone or if the animal has not been resighted 
within 15 minutes. If a marine mammal is sighted within or on a path 
toward the safety zone during pile driving, pile driving will cease 
until that animal has cleared and is on a path away from the safety 
zone or 15 minutes has lapsed since the last sighting. In addition, if 
a marine mammal not authorized to be taken under the IHA (e.g., 
humpback whale) is observed within the Level B

[[Page 66069]]

harassment zone (1,900 m), pile driving will be delayed until that 
animal has cleared and is on a path away from the safety zone or 15 
minutes has lapsed since the last sighting.

Soft-start Procedures

    A ``soft-start'' technique will be used at the beginning of each 
pile installation to allow any marine mammal that may be in the 
immediate area to leave before the pile hammer reaches full energy. For 
vibratory pile driving, the soft-start procedure requires contractors 
to initiate noise from the vibratory hammer for 15 seconds at 40-60 
percent reduced energy followed by a 1-minute waiting period. The 
procedure will be repeated two additional times before full energy may 
be achieved. For impact hammering, 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. The soft-start procedure will be 
conducted prior to driving each pile if vibratory hammering ceases for 
more than 30 minutes.

Visual Monitoring and Reporting

    The Exploratorium must designate at least one biologically-trained, 
on-site individual, approved in advance by NMFS, to monitor the area 
for marine mammals 30 minutes before, during, and 30 minutes after all 
impact pile driving activities and call for shut down if any marine 
mammal is observed within or approaching the designated Level A 
harassment zone (preliminarily set at 500 m). In addition, at least one 
NMFS-approved PSO will conduct behavioral monitoring in and around the 
Exploratorium at least two days per week for the duration of vibratory 
pile driving activities to estimate take and evaluate the behavioral 
impacts vibratory pile driving has on marine mammals out to the Level B 
harassment isopleth (1,900 m). Should a non-authorized marine mammal 
(i.e. humpback whale) be observed at any time in this zone, the 
aforementioned shut down and delay procedures will be followed.
    PSOs will be provided with the equipment necessary to effectively 
monitor for marine mammals (e.g., high-quality binoculars, compass, and 
range-finder) in order to determine if animals have entered into the 
harassment isopleths and to record species, behaviors, and responses to 
pile driving. PSOs will be required to submit a report to NMFS within 
120 days of expiration of the IHA or completion of pile driving, 
whichever comes first. The report should include data from marine 
mammal sightings (e.g., species, group size, behavior), any observed 
reactions to construction, distance to operating pile hammer, and 
construction activities occurring at time of sighting.

Estimated Take by Incidental Harassment

    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].

    Based on the Exploratorium's application and subsequent analysis, 
the impact of the described pile driving operations may result in, at 
most, short-term modification of behavior by small numbers of marine 
mammals who are within the action area. Marine mammals may avoid the 
area or temporarily halt any behaviors (e.g., foraging) at time of 
exposure. Due to the short duration of pile driving per day, animals 
are not anticipated to be exposed multiple times per day.
    Current NMFS practice regarding exposure of marine mammals to 
anthropogenic noise is that in order to avoid the potential for injury 
of marine mammals (e.g., PTS), cetaceans and pinnipeds should not be 
exposed to impulsive sounds of 180 and 190 dB rms or above, 
respectively. This level is considered precautionary as it is likely 
that more intense sounds would be required before injury would actually 
occur (Southall et al., 2007). Potential for behavioral harassment 
(Level B) is considered to have occurred when marine mammals are 
exposed to sounds at or above 160 dB rms for impulse sounds (e.g., 
impact pile driving) and 120 dB rms for non-pulse noise (e.g., 
vibratory pile driving), but below the aforementioned thresholds. These 
levels are also considered precautionary.
    Based on empirical measurements taken by Caltrans (which are 
presented in the Description of Specified Activities section above), 
estimated distances to NMFS current threshold sound levels from pile 
driving during the Exploratorium's relocation project are presented in 
Table 4. These estimates are based on the worst case scenario of 
driving the 72-inch steel piles but would be carried over for all pile 
driving. Note that despite short distances to the Level A harassment 
isopleth, the Exploratorium has proposed to implement a preliminary 
500-m marine mammal safety zone until empirical pile driving 
measurements can be made and distances to this threshold isopleth can 
be verified.

 Table 4--Modeled Underwater Distances to NMFS' Marine Mammal Harassment
                            Threshold Levels
------------------------------------------------------------------------
                                                  Level B      Level B
                                Level A  (190/   harassment   harassment
                                   180 dB)        (160 dB)     (120 dB)
------------------------------------------------------------------------
Impact hammering.............  20 m (w/o sound        100 m          n/a
                                attenuation
                                device).
Vibratory hammering..........  n/a............          n/a       1900 m
------------------------------------------------------------------------

    The estimated number of potential marine mammal takes was based on 
marine mammal monitoring reports prepared by Caltrans during similar 
activities in San Francisco Bay and on discussions with the NMFS 
Southwest Regional Office. Caltrans' SFOBB marine mammal monitoring 
reports were used to estimate the number of pinnipeds near the 
Exploratorium project area as the SFOBB site and Exploratorium are 
relatively close to each other and are similar in bathymetric features 
(e.g., water depth, substrate). However, monitoring conducted for the 
SFOBB project has been in close proximity to a haul out area, while the 
Exploratorium project is in an area of high commercial boat activity 
with no haul out sites. Therefore, the Caltrans data likely 
overestimates marine mammal abundance for the Exploratorium project 
area. Based on consultation with the NMFS Southwest Regional Office and 
review of Caltrans monitoring reports for pile driving activities in 
San Francisco Bay, the Exploratorium requested a total take of two 
Pacific harbor seals, one California sea lion, and

[[Page 66070]]

one gray whale per day of pile driving. Upon further consultation with 
NMFS Southwest Regional Office, NMFS is proposing to include harbor 
porpoise as a species potentially taken by pile driving, due to the 
recorded, albeit infrequent, sightings of harbor porpoises within San 
Francisco Bay.
    The Exploratorium estimates an average of three piles would be 
driven in a single day. Given 69 piles in total, pile driving would 
occur for approximately 23 days over the life of the project. 
Therefore, NMFS is proposing to authorize annual take, by Level B 
harassment only, of 38 Pacific harbor seals, 19 California sea lions 
incidental to the Exploratorium's pile driving activities. Due to the 
infrequent, but potential presence of harbor porpoise and gray whales 
in the area, NMFS is also proposing to authorize the take of 28 harbor 
porpoise and five gray whales, annually, based on consultation with the 
NMFS Southwest Regional Office, NMFS. These numbers are conservative 
and indicate the maximum number of animals expected to occur within the 
Level B harassment isopleth (1,900 m). Estimated and proposed level of 
take of each species is less than one percent of the affected stock 
population and therefore is considered small in relation to the 
population numbers previously set forth. The most recent harbor seal 
counts estimate the California stock of Pacific harbor seals at 34,233 
individuals and the population appears to be stabilizing at what may be 
their carrying capacity. The abundance of the U.S. stock of California 
sea lions is estimated to be 238,000 individuals and the stock is 
approaching carrying capacity. Any harbor porpoises encountered during 
the Exploratorium relocation project would likely be part of the San 
Francisco-Russian River stock which has an estimated abundance of 9,189 
animals and has steadily increased since 1993 (although the increase is 
not statistically significant). Lastly, the most recent 2008 stock 
assessment report estimated the Eastern North Pacific gray whale stock 
to be approximately 18,813 individuals with an increasing population 
trend over the past several decades.

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.''
    NMFS has determined that the impact of pile driving within the 
Exploratorium's action area, as described in this notice and the IHA 
application, may result in the temporary modification in behavior 
(Level B harassment) of small numbers of marine mammals. Further, this 
activity is expected to result in a negligible impact on the affected 
species or stocks of marine mammals. The provision requiring that the 
activity not have an unmitigable impact on the availability of the 
affected species or stock of marine mammals for subsistence use is not 
implicated for this action.
    For reasons stated previously in this document, the specified 
activities associated with relocation of the Exploratorium are not 
likely to cause TTS, PTS, or other non-auditory injury, serious injury, 
or death to affected marine mammals because of the following:
    (1) The fact that sound pressure levels from vibratory pile driving 
in San Francisco Bay will not exceed 180 dB rms;
    (2) The limited use of an impact hammer during pile driving;
    (3) The use of sound attenuation devices (e.g., wood block, bubble 
curtain) during all impact hammering;
    (4) The monitoring requirements during all impact pile driving and 
during vibratory pile driving two full days per week; and
    (5) The incorporation of other required mitigation measures (i.e., 
shut-down, soft-starts).
    As a result, no take by injury, serious injury, or death is 
anticipated or authorized, and the potential for temporary or permanent 
hearing impairment is very low and will be avoided through the 
incorporation of the required monitoring and mitigation measures.
    While the number of marine mammals potentially incidentally 
harassed will depend on the distribution and abundance of marine 
mammals in the vicinity of the pile driving activities, the number of 
potential Level B incidental harassment takings is estimated to be 
small (less than one percent) relative to the estimated population 
sizes and has been mitigated to the lowest level practicable through 
incorporation of the monitoring and mitigation measures previously 
addressed in this document. No known foraging sites occur around Piers 
15/17 and the closest pinniped haul out area is 3 km away.

Impact on Availability of Affected Species for Taking for Subsistence 
Uses

    There are no relevant subsistence uses of marine mammals implicated 
by this action.

Endangered Species Act (ESA)

    No marine mammal species listed under the ESA are anticipated to 
occur within the action area; therefore, ESA consultation on issuance 
of the proposed IHA was not required. However, other ESA-listed species 
under NMFS' jurisdiction do occur within the action area. On May 28, 
2010, the NMFS Southwest Regional Office concluded Section 7 and EFH 
consultation with the U.S. Army Corps of Engineers (Corps) on issuance 
of a Corps permit to the Exploratorium. Both parties concurred that 
adequate measures are in place to avoid, minimize, mitigate, or 
otherwise offset adverse effects to EFH.

National Environmental Policy Act (NEPA)

    On October 15, 2010, NMFS released an Environmental Assessment (EA) 
and Finding of No Significant Impact (FONSI) for the Exploratorium 
relocation project. NMFS determined that issuance of the IHA would not 
significantly impact the quality of the human environment and that 
preparation of an Environmental Impact Statement was not required.

    Dated: October 14, 2010.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2010-27178 Filed 10-26-10; 8:45 am]
BILLING CODE 3510-22-P