Agency Information Collection Activities; Proposals, Submissions, and Approvals: Exploratorium Relocation Project in San Francisco, CA, 42691-42698 [2010-18002]


[Federal Register: July 22, 2010 (Volume 75, Number 140)]
[Page 42691-42698]
From the Federal Register Online via GPO Access []



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; proposed incidental harassment authorization; request 
for comments.


SUMMARY: NMFS has received a complete and adequate application from the 
Exploratorium for an Incidental Harassment Authorization (IHA) to take 
marine mammals, by harassment, incidental to pile driving during the 
Exploratorium's relocation project. Pursuant to the Marine Mammal 
Protection Act (MMPA), NMFS is proposing to issue an IHA to the 
Exploratorium to incidentally harass, by Level B harassment only, four 
species of marine mammals during the specified activity within a 
specific geographic area and is requesting comments on its proposal.

DATES: Comments and information must be received no later than August 
23, 2010.

ADDRESSES: Comments on the application and this proposal should be 
addressed to Michael Payne, Chief, Permits, Conservation and Education 
Division, Office of Protected Resources, National Marine Fisheries 
Service, 1315 East-West Highway, Silver Spring, MD 20910-3225. The 
mailbox address for providing email comments is 
NMFS is not responsible for e-mail comments sent to addresses other 
than the one provided here. Comments sent via e-mail, including all 
attachments, must not exceed a 10-megabyte file size.
    Instructions: All comments received are a part of the public record 
and will generally be posted to
incidental.htm without change. All Personal Identifying Information 
(for example, name, address, etc.) voluntarily submitted by the 
commenter may be publicly accessible. Do not submit Confidential 
Business Information or otherwise sensitive or protected information.
    A copy of the application containing a list of the references used 
in this document may be obtained by writing to the address specified 
above, telephoning the contact listed below (see FOR FURTHER 
INFORMATION CONTACT), or visiting the internet at:https:// Documents cited in this 
notice may also 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.



    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 
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 '' 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

[[Page 42692]]

apply for an authorization to incidentally take small numbers of marine 
mammals by harassment. Section 101(a)(5)(D) establishes a 45-day time 
limit for NMFS review of an application followed by a 30-day public 
notice and comment period on any proposed authorizations for the 
incidental harassment of marine mammals. Within 45 days of the close of 
the comment period, NMFS must either issue or deny the authorization.
    A. 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 Pacific 
harbor seals (Phoca vitulina richardii), California sea lions (Zalophus 
californianus), harbor porpoises (Phocoena phocoena), and gray whales 
(Eschrichtius robustus) incidental to relocation of the Exploratorium 
museum. Upon receipt of additional information, NMFS determined the 
application complete and adequate on June 1, 2010.
    The Exploratorium proposes to relocate from the Palace of Fine Arts 
to Piers 15 and 17, along San Francisco's waterfront. The relocation 
project would include the installation, repair, and removal of piles at 
Pier 15, removal of wharf decking between Piers 15 and 17, and 
expansion of the southern portion of Pier 15. The Exploratorium 
proposes to install up to 69 new steel piles and repair and remove 
existing piles by hydraulic or hand-held cutting tools. Because pile 
driving has the potential to result in marine mammal harassment, NMFS 
is proposing to issue an IHA for take incidental to this specified 

Description of the Specified Activity

    The Exploratorium proposes to relocate from 3601 Lyon Street to 
Piers 15 and 17, along the Embarcadero of San Francisco's waterfront. 
The relocation project is scheduled to commence as early as September 
2010 and construction would continue throughout a 26-month period. 
However, of the activities associated with the relocation, only pile 
driving has the potential to result in marine mammal take and this 
activity is expected to be complete by the spring of 2011.
    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) would be installed around Piers 15 and 17 using a 
vibratory hammer (Table 1). Between two and five steel piles (average 
of three piles) would be installed daily, depending on their size and 
the amount of time necessary to install them. Each pile would 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, with 15 hours spent on 72-inch piles, five hours spent on 
20-inch piles, and eight hours spent on 24-inch piles. All piles would 
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 would use a steam or 
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 
would be limited to 120, 25, and 5, respectively. Sound attenuation 
devices (e.g., wood block, bubble curtain) would be used during any 
impact hammering. In addition, impact hammering would not occur between 
June 1 and November 30 to prevent injury to listed salmonids.
    In addition to pile driving, the Exploratorium would repair or 
remove existing piles (Table 1) and remove existing wharf decking. 
Existing concrete piles would 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 would 
be suspended from a crane on deck. In-water noise from this work would 
be negligible. Pile repair would include installing a fiberglass shell 
around damaged pile and filling the shell with concrete. The work would 
be completed by divers using hand tools and does not involve loud 
noise. Furthermore, there are no marine mammal haul out sites at Piers 
15 and 17 and deck height in the area is at elevations generally too 
high to facilitate marine mammal haul out. Deck removal and expansion 
would occur outside of habitat for marine mammals. Therefore, removal 
and expansion of the existing pier decking would not likely result in 
harassment of marine mammals. Finally, there would be two to ten barges 
or floats at any given time in the water to support construction 
activities; however, these would 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 not anticipated.

 Table 1. Summary of pile activities during the Exploratorium relocation
        Activity         Maximum Number of Piles         Location
Installation of new         69 steel piles        Marginal Wharf; South
 piles                   (30 72-inch diameter                Apron
                              steel piles,
                         26 24-inch steel piles,
                                    and 13
                         20-inch steel piles)
Repair of existing                    1026        Pier 15; Valley Infill
 piles                                                       Area;
                                                  Marginal Wharf; North
Extension of existing                  120        Valley Infill Area
Removal of existing                    837        Marginal Wharf; Valley
 piles-- cut at mudline                           Removal Area; South
                                                    Apron; Pier 15
Removal of existing                    306        Valley Removal Area;
 piles--cut above mean                              Marginal Wharf
 lower low 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

[[Page 42693]]

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 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 measured sound 
pressure levels (SPLs) 5 m from the hammer were below 180 dB root mean 
square (rms) values. 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 proposes to use is 40% of the 
energy of the King Kong hammer; therefore, source levels would 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. Therefore, it is anticipated that noise from pile 
driving will dissipate very quickly around the Exploratorium.

Table 2. Measured sound pressure levels during vibratory pile driving in
                   San Francisco Bay (Caltrans, 2007).
     Pile Type/Size        Relative Water 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

    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).
     Pile Type/Size        Relative Water 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

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. Therefore, these two species are not considered 
further in this proposed IHA notice.

Pacific Harbor Seals

    Pacific harbor seals are found in the coastal and estuarine waters 
off Baja, California, north to British Columbia, west through the Gulf 
of Alaska, and in the Bering Sea. The most recent harbor seal counts 
estimate the California stock of Pacific harbor seals at 34,233 
individuals. The population appears to be stabilizing at what may be 
their carrying capacity and human-caused mortality is declining (NMFS, 
2005). The California stock of Pacific harbor seals is not listed under 
the Endangered Species Act (ESA) nor considered strategic under the 
    In California, approximately 400-500 harbor seal haul out sites are 
widely distributed along the mainland and offshore islands, including 
intertidal sandbars, rocky shores, and beaches. The north side of Yerba 
Buena Island is the closest haul out area to the relocation project, 
approximately 3 km from Piers 15 and 17. Although harbor seals use this 
haul out year-round, Yerba Buena Island is not considered a pupping 
site. In California breeding occurs from March to May, and pupping 
between April and May depending on local populations. Harbor seals 
around the new Exploratorium site would likely be transiting to and 
from their closest haul out (Yerba Buena Island) or opportunistically 
foraging. Herring spawning events could result in harbor seals 
congregating and approaching the action area sporadically in an 
unpredictable manner (pers. comm., M. DeAngelis to M. Magliocca).
    Pinnipeds produce a wide range of social signals, most occurring at 
relatively low frequencies (Southall et al., 2007), suggesting that 
hearing is keenest at these frequencies. Pinnipeds communicate 
acoustically both on land and in the water, but have different hearing 
capabilities dependent upon the medium (air or water). Based on 
numerous studies, as summarized in Southall et al. (2007), pinnipeds 
are more sensitive to a broader range of sound frequencies underwater 
than in air. Underwater, pinnipeds can hear frequencies from 75 Hz to 
75 kHz. In air, the lower limit remains at 75 Hz but the highest 
audible frequencies are only around 30 kHz (Southall et al., 2007).

[[Page 42694]]

California Sea Lions

    California sea lions are found throughout the Eastern North Pacific 
Ocean in shallow coastal and estuarine waters, ranging from Central 
Mexico to British Columbia, Canada. Their primary breeding range 
extends from Central Mexico to the Channel Islands in Southern 
California. The abundance of the U.S. stock is estimated to be 238,000 
sea lions (NMFS, 2007). This stock is approaching carrying capacity and 
is reaching ``optimum sustainable population'' limits, as defined by 
the MMPA. California sea lions are not listed under the ESA nor 
considered strategic under the MMPA.
    Sandy beaches are preferred habitat for haul out sites, but marina 
docks, jetties, and buoys are often used in California for resting, 
breeding, and molting. In San Francisco Bay, sea lions haul out on 
floating docks (e.g., Pier 39 around Fishermen's Wharf) and on buoys 
throughout the Bay. Breeding season begins in May and lasts until 
August, with most pups born by July. While onshore, California sea 
lions often form groups of several hundred animals. No sea lion 
haulouts are located around the Exploratorium. However, sea lions 
observed within this area may be transiting to and from nearby piers or 
opportunistically foraging.

Harbor Porpoises

    Harbor porpoises have a wide and discontinuous range that includes 
the North Atlantic and North Pacific. In the Eastern North Pacific, 
harbor porpoises are found in coastal and inland waters from Point 
Conception, California to Alaska. Harbor porpoises in U.S. waters are 
divided into 10 stocks, based on genetics, movement patterns, and 
management. Any harbor porpoises encountered during the Exploratorium 
relocation would likely be part of the San Francisco-Russian River 
stock which has an estimated abundance of 9,189 animals. Abundance of 
the San Francisco-Russian River stock appeared to be stable or 
declining between 1988 and 1991 and has steadily increased since 1993, 
although this increase is not statistically significant. Harbor 
porpoises are not commonly sighted in San Francisco Bay, but have been 
observed traveling in small pods of two to three animals on occasion 
(pers. comm., M. DeAngelis to M. Magliocca). They may occur in the 
action area during a time when they could be affected by pile driving 
activities; however, their presence in the vicinity is rare. Harbor 
porpoises in California are not listed under the ESA nor considered 
strategic under the MMPA.
    Cetaceans are divided into three functional hearing groups: low-
frequency, mid-frequency, and high frequency. Harbor porpoises are 
considered high-frequency cetaceans and their estimated auditory 
bandwidth (lower to upper frequency hearing cut-off) ranges from 200 Hz 
to 180 kHz.

Gray Whales

    Gray whales are large mysticetes, or baleen whales, found mainly in 
shallow coastal waters of the North Pacific Ocean. Two isolated 
geographic distributions of gray whales exist: the Eastern North 
Pacific stock and the Western North Pacific stock. The Eastern North 
Pacific stock migrates as far south as Baja, California for breeding 
and calving in the winter and as far north as the Bering and Chukchi 
Seas for summer feeding. During migration, gray whales will 
occasionally enter rivers and bays, including San Francisco Bay, along 
the coast, but in very low numbers. They could potentially be in the 
action area during pile driving activities. The most recent 2008 stock 
assessment report estimated the Eastern North Pacific stock to be 
approximately 18,813 individuals with an increasing population trend 
over the past several decades. Gray whales were delisted from the ESA 
in 1994 and are not considered strategic under the MMPA.
    Gray whales, like other baleen whales, are in the low-frequency 
hearing group. There are no empirical data on gray whale hearing; 
however, Wartzok and Ketten (1999) suggest that mysticete hearing is 
most sensitive at the same frequencies at which they vocalize. 
Underwater sounds produced by gray whales range from 20 Hz to 20 kHz 
(Richardson et al., 1995).

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. No pinnipeds on haulouts would be affected as 
the closest haulout is approximately 3 kms away; therefore, in-air 
noise is not a concern. Marine mammals are continually exposed to many 
sources of sound. Naturally occurring sounds such as lightning, rain, 
sub-sea earthquakes, and biological sounds (e.g., snapping shrimp, 
whale songs) are ubiquitous throughout the world's oceans. 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 [gteqt] 40 dB (i.e., 40 
dB of TTS). Due to proposed mitigation measures and source levels, NMFS 
does not expect that marine mammals would be exposed to levels that 
could elicit PTS; therefore, it will not be discussed further.

Temporary Threshold Shift (TTS)

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

[[Page 42695]]

pinniped 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 microPa for 25 minutes. In contrast, a tested 
sea lion exhibited TTS-onset at 174 dB re: 1 microPa 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 microPa (peak-to-peak) (Finneran et al., 2003). There is no 
information on species-specific TTS for harbor porpoises or gray 
    There are limited data available on the effects of non-pulse noise 
(e.g., vibratory pile driving) on pinnipeds in-water; however, field 
and captive studies to date collectively suggest that pinnipeds do not 
strongly react to exposures between 90-140 dB re: 1 microPa; no data 
exist from exposures at higher levels. Jacobs and Terhune (2002) 
observed wild harbor seal reactions to high frequency acoustic 
harassment devices (ADH) around nine sites. Seals came within 44 m of 
the active ADH and failed to demonstrate any behavioral response when 
received SPLs were estimated at 120-130 dB. In a captive study 
(Kastelein, 2006), a group of seals were collectively subjected to data 
collection and communication network (ACME) non-pulse sounds at 8-16 
kHz. Exposures between 80-107 dB did not induce strong behavioral 
responses; however, a single observation at 100-110 dB indicated an 
avoidance response at this level. The group returned to baseline 
conditions shortly following exposure. Southall et al. (2007) notes 
contextual differences between these two studies noting that the 
captive animals were not reinforced with food for remaining in the 
noise fields, whereas free-ranging subjects may have been more tolerant 
of exposures because of motivation to return to a safe location or 
approach enclosures holding prey items. While most of the pile driving 
will be vibratory, a small portion of piles may be driven using an 
impact hammer (pulse noise) and sound attenuation devices, resulting in 
anticipated hydroacoustic levels between 164 and 179 dB RMS. Southall 
et al. (2007) reviewed relevant data from studies involving pinnipeds 
exposed to pulse noise and concluded that exposures to 150 to 180 dB 
(approximate source level range for vibratory pile driving) generally 
have limited potential to induce avoidance behavior.
    Vibratory pile driving emits low frequency broadband noise, all of 
which may be detectable by marine mammals within the action area. 
However, lower frequency hearing animals such as pinnipeds and gray 
whales are likely to be able to hear the sound better and farther away 
than the harbor porpoise, who has a hearing range of 200 Hz-180 kHz 
(Southall et al., 2007), as most of the energy during vibratory pile is 
expected to be below 600 Hz (Caltrans 2007). 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). 
Seals would likely also exhibit tolerance or habituation (as described 
in Richardson et al., 1999) due to the amount of anthropogenic use 
within the action area and San Francisco Bay as a whole.
    Pacific harbor seal and California sea lion pupping season is 
outside of the temporal pile driving schedule; therefore, no impacts to 
reproduction are anticipated. It is expected that marine mammals 
exposed to pile driving noise would be using the adjacent waters around 
the Exploratorium's project site for foraging or as a daily migration 
route between foraging grounds and haul out locations. Harbor porpoises 
also may use the adjacent waters for foraging and may pass through the 
area during pile driving. Gray whales are not expected to forage in the 
activity area, but may display behavioral changes in response to noise 
if they enter San Francisco Bay and transit or linger around the action 
area during their annual migration.
    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 would 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 observers (PSO) would 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

    On May 28, 2010, the NMFS Southwest Regional Office concluded 
section 7 and Essential Fish Habitat (EFH) consultation, under the ESA 
and Magnuson Stevens Fishery Conservation and Management Act (MSFCMA), 
respectively, with the U.S. Army Corps of Engineers (Corps) on issuance 
of a Corps permit to the Exploratorium. In summary, NMFS Southwest 
Regional Office found that the proposed construction activities may 
affect ESA-listed fish by generating increased levels of turbidity and 
sound; however, these impacts are expected to be minor, localized, and 
short term. As such, NMFS Southwest Regional Office concurred with the 
Corps determination that impacts from the Exploratorium's project would 
not result in adverse impacts to ESA-listed fish or their critical 
habitat. NMFS Southwest Regional Office also determined that the 
proposed project would adversely affect EFH for various federally-
managed species within the Pacific Groundfish, Coastal Pelagic, and 
Pacific Salmonid Fishery Management Plans; however, they also 
determined that the proposed action contains adequate measures to 
avoid, minimize, mitigate, or otherwise offset the adverse effects to 
    Marine mammals and fish may occupy the same habitat. Pile driving 
noise would result in degradation of in-water habitat; however, this 
impact would be short term and localized. Installation of new piles 
would be permanent; however, overall site

[[Page 42696]]

conditions are anticipated to be substantively unchanged from existing 
conditions for marine mammals following project implementation. 
Therefore, following results of consultation under the ESA and MSFCMA, 
NMFS has preliminarily determined impacts to marine mammal habitat are 

Proposed 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 Exploratorium has proposed the following mitigation measures to 
help ensure the least practicable adverse impact on marine mammals:

Limited Use of an Impact Hammer

    All piles would 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 would be used as an attenuation device to 
reduce hydroacoustic sound levels to avoid the potential for injury. 
With the use of these devices, hydroacoustic source levels are 
anticipated to be between 164 and 179 dB RMS during impact hammering.

Establishment of a Safety Zone

    During all in-water impact pile driving, the Exploratorium would 
establish a preliminary marine mammal safety zone of 500 m around each 
pile before pile driving commences. 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 would notify the 
Resident Engineer (or other authorized individual) who would 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 should 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 harassment zone (1900 
m), pile driving would 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 would 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% 
reduced energy followed by a 1-minute waiting period. The procedure 
would be repeated two additional times before full energy may be 
achieved. For impact hammering, contractors would be required to 
provide an initial set of three strikes from the impact hammer at 40% 
energy, followed by a 1-minute waiting period, then two subsequent 
three-strike sets. The soft-start procedure would be conducted prior to 
driving each pile if vibratory hammering ceases for more than 30 
    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable adverse impact on the affected marine mammal species and 
stocks and their habitat. Our evaluation of potential measures included 
consideration of the following factors in relation to one another: (1) 
the manner in which, and the degree to which, the successful 
implementation of the measure is expected to minimize adverse impacts 
to marine mammals; (2) the proven or likely efficacy of the specific 
measure to minimize adverse impacts as planned; and (3) the 
practicability of the measure for applicant implementation, including 
consideration of personnel safety, and practicality of implementation.
    Based on our evaluation of the applicant's proposed measures, NMFS 
has preliminarily determined that the proposed mitigation measures 
provide the means of effecting the least practicable adverse impacts on 
marine mammals species or stocks and their habitat, paying particular 
attention to rookeries, mating grounds, and areas of similar 

Proposed Monitoring and Reporting

    In order to issue an IHA 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 on populations of marine 
mammals that are expected to be present.
    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 (preliminary set at 500 m). In addition, at least one 
NMFS-approved PSO would conduct behavioral monitoring in and around the 
Exploratorium at least two days per week between March 1 and November 
30 to estimate take and evaluate the behavioral impacts 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 would be followed.
    As set forth in the Exploratorium's application to the Corps, 
monitoring for herring spawning events would be conducted on a daily 
basis between December 1 and February 28. This PSO would also monitor 
for marine mammals within and around the Level B harassment area. In 
addition to stationing a PSO to monitor for herring, the Exploratorium 
would cease pile driving for two weeks should a herring spawning event 
occur (a measure designed to reduce impacts to fish). Pinniped presence 
during such events can be sporadic and unpredictable; therefore, the 
requirements set forth under ESA and EFH consultation also minimize and 
allow for monitoring of impacts to marine mammals.
    PSOs would 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 would be required to submit a

[[Page 42697]]

report to NMFS within 120 days of expiration of the IHA or completion 
of pile driving, whichever comes first. The report would 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 halt any behaviors (e.g., foraging) at time of exposure. Due to 
the short duration of pile driving per day (1- 2.5 hours), 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 120dB 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 (190/180   harassment (160  harassment (120
                            dB)               dB)              dB)
Impact hammering    20 m (w/o sound          100 m              n/a
Vibratory                      n/a             n/a           1900 m

    The estimated number of marine mammals potential taken 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 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 19 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 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 

Negligible Impact and Small Numbers Analysis and Determination

    NMFS has defined ``negligible impact'' in 50 CFR 216.103 as '' 
impact resulting from the specified activity that cannot be reasonably 
expected to, and is not reasonably likely to, adversely affect the 
species or stock through effects on annual rates of recruitment or 
survival.'' In making a negligible impact determination, NMFS considers 
a number of factors which include, but are not limited to, number of 
anticipated injuries or mortalities (none of which would be authorized 
here), number, nature, intensity, and duration of Level B harassment, 
and the context in which takes occur (e.g., will the takes occur in an 
area or time of significance for marine mammals, are takes occurring to 
a small, localized population?).
    As described above, marine mammals would not be exposed to 
activities or sound levels which would result in injury (e.g., PTS), 
serious injury, or mortality. Pile driving would occur in shallow 
coastal waters of San Francisco Bay to stocks occurring throughout 
California, and, for gray whales, the eastern Pacific Ocean. The action 
area (waters around Piers 15-17) is not considered as providing 
significant habitat for harbor seals. The closest haulout is 3 kms away 
on Yerba Buena Island; however, noise levels about NMFS harassment 
thresholds would only extend to 1,900 m in-water. Marine mammals 
approaching the action area would likely be traveling or 
opportunistically foraging. However, marine mammals foraging on herring 
runs would not be affected by

[[Page 42698]]

construction because the Exploratorium would not conduct pile driving 
for two weeks if a herring run is observed by the on-site PSO, who 
would monitor the area daily between December 1- February 28. In 
addition, a PSO would monitor for marine mammals twice a day to 
estimate take and verify impacts to marine mammals are not above those 
described here. The amount of take the Exploratorium has requested, and 
NMFS proposes to authorize, is considered small (less than one percent) 
relative to the estimated populations of 34,233 Pacific harbor seals, 
238,000 California sea lions, 9,189 harbor porpoises, and 18,813 gray 
whales. As previously noted, no affected marine mammals are listed 
under the ESA or considered strategic under the MMPA.
    Marine mammals may be temporarily impacted by pile driving noise. 
However, marine mammals are expected to avoid the area, thereby 
reducing exposure and impacts. Further, although the relocation project 
is expected to take up to two years, installation of the 69 steel piles 
would only occur for approximately 19 days. Further, San Francisco Bay 
is a highly industrialized area and species such as harbor seals and 
California sea lions flourish throughout the Bay. Therefore, animals 
are likely tolerant or habituated to anthropogenic disturbance, 
including low level vibratory pile driving operations, and noise from 
other anthropogenic sources (e.g., vessels in the adjacent shipping 
lane) may mask construction related sounds. Finally, breeding and 
pupping season occur outside of the proposed pile driving timeframe; 
therefore, no disruption to reproductive behavior is anticipated. There 
is no anticipated effect on annual rates of recruitment or survival of 
affected marine mammals.
    Based on the analysis contained herein of the likely effects of the 
specified activity on marine mammals and their habitat, and taking into 
consideration the implementation of the mitigation and monitoring 
measures, NMFS preliminarily determines that the Exploratorium's 
relocation project will result in the incidental take of small numbers 
of marine mammals, by Level B harassment only, and that the total 
taking from will have a negligible impact on the affected species or 

Impact on Availability of Affected Species for Taking for Subsistence 

    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, Section 7 consultation under 
the ESA is not required.

National Environmental Policy Act (NEPA)

    In compliance with the National Environmental Policy Act of 1969 
(42 U.S.C. 4321 et seq.), as implemented by the regulations published 
by the Council on Environmental Quality (40 CFR parts 1500-1508), and 
NOAA Administrative Order 216-6, NMFS is preparing an Environmental 
Assessment (EA) to consider the direct, indirect, and cumulative 
effects to marine mammals and other applicable environmental resources 
resulting from issuance of a one-year IHA and the potential issuance of 
additional authorization for incidental harassment for the ongoing 
project. Upon completion, this EA will be available on the NMFS website 
listed in the beginning of this document.

    Dated: July 16, 2010.
James H. Lecky,
Director, Office of Protected Resources, National Marine Fisheries 
[FR Doc. 2010-18002 Filed 7-21-10; 8:45 am]
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