Taking of Marine Mammals Incidental to Specified Activities; Construction of the East Span of the San Francisco-Oakland Bay Bridge, 2371-2377 [2013-00381]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 78, Number 8 (Friday, January 11, 2013)]
[Notices]
[Pages 2371-2377]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-00381]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XA933


Taking of Marine Mammals Incidental to Specified Activities; 
Construction of the East Span of the San Francisco-Oakland Bay Bridge

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

ACTION: Notice of issuance of an incidental harassment authorization.

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SUMMARY: In accordance with provisions of the Marine Mammal Protection 
Act (MMPA) as amended, notification is hereby given that an Incidental 
Harassment Authorization (IHA) has been issued to the California 
Department of Transportation (CALTRANS) to take small numbers of 
California sea lions, Pacific harbor seals, harbor porpoises, and gray 
whales, by harassment, incidental to construction of a replacement 
bridge for the East Span of the San Francisco-Oakland Bay Bridge (SF-
OBB) in California.

DATES: This authorization is effective from January 8, 2013, until 
January 7, 2014.

ADDRESSES: A copy of the application, IHA, and/or a list of references 
used in this document may be obtained 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.

FOR FURTHER INFORMATION CONTACT: Shane Guan, NMFS, (301) 427-8418, ext 
137, or Monica DeAngelis, NMFS, (562) 980-3232.

SUPPLEMENTARY INFORMATION:

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, the taking is 
limited to harassment, notice of a proposed authorization is provided 
to the public for review.
    Permission shall be granted if NMFS finds that the taking will have 
a negligible impact on the species or

[[Page 2372]]

stock(s) and will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for certain subsistence uses 
and if the permissible methods of taking and requirements pertaining to 
the mitigation, monitoring, and reporting of such taking 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. 
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].''
    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 
small numbers of marine mammals. Within 45 days of the close of the 
comment period, NMFS must either issue or deny issuance of the 
authorization.

Summary of Request

    On October 19, 2011, CALTRANS submitted a request to NOAA 
requesting an IHA for the possible harassment of small numbers of 
California sea lions (Zalophus californianus), Pacific harbor seals 
(Phoca vitulina richardsii), harbor porpoises (Phocoena phocoena), and 
gray whales (Eschrichtius robustus) incidental to construction 
associated with a replacement bridge for the East Span of the SF-OBB, 
in San Francisco Bay (SFB), California. The proposed construction 
activities would last for approximately three years, starting 2013. 
After receiving NMFS comments on the IHA application regarding proposed 
monitoring measures, CALTRANS submitted a revised IHA application on 
April 23, 2012. The action discussed in this document is based on 
CALTRANS April 23, 2012, IHA application and NMFS Federal Register 
notice for the proposed IHA (77 FR 50473; August 21, 2012).
    An IHA was previously issued to CALTRANS for this activity on 
February 7, 2011 and it expired on February 6, 2012 (76 FR 7156, 
February 9, 2011). No in-water construction activity was conducted 
during the period covered by that IHA. CALTRANS' renewal application 
indicates that the next stage of the construction activities will 
involve dismantling of the existing bridge, which is expected to start 
in fall 2013. However, some preparatory construction activities related 
to the dismantling may take place before the planned schedule. A 
detailed description of the proposed SF-OBB East Span project is 
provided in the CALTRANS' IHA application and in the Federal Register 
for the proposed IHA (77 FR 50473, August 21, 2012), and there is no 
change to the description of the activities. Therefore, the detailed 
description of the proposed construction activities is not repeated 
here, except for certain information that was missing in the earlier 
documents.

Supplemental Information Regarding CALTRANS Construction Activities

    As stated in the IHA application and the Federal Register notice 
for the proposed IHA (77 FR 50473; August 21, 2012), work at the Yerba 
Buena Island (YBI) access would involve the construction of a small 
(approximately 650 m\2\, or 7,000 ft\2\) H-pile supported trestle. The 
size of the H-pile was not identified in the proposed IHA. Discussion 
with CALTRANS indicated that it is unclear the size of the H-piles 
would be used. However, it is known that the contractor would most 
likely use HP H-piles, which with dimensions between 9.70 x 10.075 in. 
and 14.21 x 14.885 in., with length between 25 and 100 feet.
    CALTRANS also stated that it's very unlikely that multiple pile 
driving would occur simultaneously. If in the case that more than one 
contractor would be employed to conduct the construction activity, 
maximum of two pile work could occur and most likely it would be one 
pile driving and one pile removal.
    In addition, NMFS also worked with CALTRANS to revise the size of 
the exclusion zones and Level B harassment zones due to the lack of on-
site data to establish specific zones for driving of 24- and 36-in 
piles, H-piles, and sheet piles. CALTRANS agreed that it will use the 
data of 48-in piles to establish the temporary exclusion zones and 
Level B harassment zones based on in-situ measurements conducted in 
2009 (CALTRANS 2009) before revised zones are established based on on-
site measurements during the test pile driving. Likewise, for vibratory 
pile driving, if hydroacoustic monitoring indicates that sound levels 
have the potential to exceed the 180 or 190 dB SPL, corresponding 
exclusion zones will be established. The temporary exclusion zones and 
Level B zones for various pile driving and dismantling activities are 
listed in Table 1.

                      Table 1--Temporary Exclusion and Level B Harassment Zones for Various Pile Driving and Dismantling Activities
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                                                              Distance to 120 dB re  Distance to 160 dB re  Distance to 180 dB re  Distance to 190 dB re
Pile driving/dismantling activities       Pile size (m)       1 [micro]Pa (rms) (m)  1 [micro]Pa (rms) (m)  1 [micro]Pa (rms) (m)  1 [micro]Pa (rms) (m)
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Vibratory Driving..................  24....................  2,000.................  NA...................  NA...................  NA
                                    --------------------------------------------------------------------------------------------------------------------
                                     36....................  2,000.................  NA...................  NA...................  NA
                                    --------------------------------------------------------------------------------------------------------------------
                                     Sheet pile............  2,000.................  NA...................  NA...................  NA
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Attenuated Impact Driving..........  24....................  NA....................  1,000................  235..................  95
                                    --------------------------------------------------------------------------------------------------------------------
                                     36....................  NA....................  1,000................  235..................  95
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Unattenuated Proofing..............  24....................  NA....................  1,000................  235..................  95
                                    --------------------------------------------------------------------------------------------------------------------

[[Page 2373]]

 
                                     36....................  NA....................  1,000................  235..................  95
--------------------------------------------------------------------------------------------------------------------------------------------------------
Unattenuated Impact Driving........  H-pile................  NA....................  1,000................  235..................  95
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Dismantling........................  ......................  2,000.................  NA...................  100..................  100
--------------------------------------------------------------------------------------------------------------------------------------------------------

Comments and Responses

    A notice of receipt and request for public comment on the 
application and proposed authorization was published on August 21, 2012 
(77 FR 50473). During the 30-day public comment period, the Marine 
Mammal Commission (Commission) provided the only comment.
    Comment 1: The Commission recommends that NMFS promulgate 
regulations and condition them to require further public review if 
CALTRANS or the contractor proposes any substantial changes to the 
project plan.
    Response: In the Federal Register notice for the proposed IHA (77 
FR 50473; August 21, 2012), NMFS noted that CALTRANS' dismantling of 
the existing east span SF-OBB may take up to five years to complete, 
therefore, a five-year letter of authorization (LOA) under a rulemaking 
may seem to be preferable. However, subsequent discussion with CALTRANS 
indicated that activities involving the existing bridge dismantling are 
likely to differ from year to year, and the agency may not be able to 
predict annual construction activities in advance. Further, the 
proposed dismantling activities could be completed in two to three 
years. Therefore, at this stage, NMFS concludes that the current best 
course of action for CALTRANS is to pursue annual IHAs.
    Comment 2: The Commission requests NMFS require CALTRANS to 
implement full-time monitoring of Level A and B harassment zones during 
all in-water sound-producing activities (i.e., pile-driving and removal 
and bridge dismantlement activities).
    Response: NMFS discussed with CALTRANS on marine mammal monitoring 
during its proposed in-water construction activities. As described in 
the Federal Register notice for the proposed IHA (77 FR 50473; August 
21, 2012) and in CALTRANS IHA application, CALTRANS' planned 
construction includes an average annual installation of up to 635 
temporary falsework piles, 1,925 steel sheet piles, and various 
mechanical dismantling activities. The extent of the work made it 
infeasible and costly to implement marine mammal monitoring for Level A 
and B harassment zones at all times, particularly since some of the 
Level B harassment zone for vibratory pile driving extends to a radius 
of 2 km. CALTRANS agrees to monitor the 180 and 190 dB exclusion zones 
and 160 dB behavioral harassment zone for all unattenuated impact pile 
driving of H-piles, and the 180 and 190 dB exclusion zones for 
attenuated impact pile driving and mechanical dismantling. CALTRANS 
will also monitor the 160 dB behavioral harassment zone for 20% of the 
attenuated impact pile driving, and 120 dB behavioral harassment zone 
for 20% of vibratory pile driving and mechanic dismantling. However, 
CALTRANS will not monitor the unattenuated impact pile proofing, which 
only lasts for less than one minute. Proposed proofing of piles will be 
limited to a maximum of two piles per day, and for less than 1 minute 
per pile, administering a maximum of twenty blows per pile. CALTRANS 
states, and NMFS agrees, that the logistics of scheduling and 
mobilizing a monitoring team for activities that will last less than 
one minute is not practical.

Description of Marine Mammals in the Area of the Specified Activity

    General information on the marine mammal species found in 
California waters can be found in Caretta et al. (2011), which is 
available at the following URL: https://www.nmfs.noaa.gov/pr/pdfs/sars/po2010.pdf. Refer to that document for information on these species.
    The marine mammals most likely to be found in the SF-OBB area are 
the California sea lion, Pacific harbor seal, and harbor porpoise. From 
December through May gray whales may also be present in the SF-OBB 
area. Information on California sea lion, harbor seal, and gray whale 
was provided in the November 14, 2003 (68 FR 64595), Federal Register 
notice; information on harbor porpoise was provided in the January 26, 
2006 (71 FR 4352), Federal Register notice.

Potential Effects on Marine Mammals and Their Habitat

    CALTRANS and NMFS have determined that open-water pile driving and 
pile removal, as well as dredging and dismantling of concrete 
foundation of existing bridge by saw cutting, flame cutting, mechanical 
splitting, drilling, pulverizing and/or hydro-cutting, as outlined in 
the project description, has the potential to result in behavioral 
harassment of California sea lions, Pacific harbor seals, harbor 
porpoises, and gray whales that may be swimming, foraging, or resting 
in the project vicinity while pile driving is being conducted. Pile 
driving and removal could potentially harass those few pinnipeds that 
are in the water close to the project site, whether their heads are 
above or below the surface.
    Marine mammals exposed to high intensity sound repeatedly or for 
prolonged periods can experience hearing threshold shift (TS), which is 
the loss of hearing sensitivity at certain frequency ranges (Kastak et 
al. 1999; Schlundt et al. 2000; Finneran et al. 2002; 2005). TS can be 
permanent (PTS), in which case the loss of hearing sensitivity is 
unrecoverable, or temporary (TTS), in which case the animal's hearing 
threshold will recover over time (Southall et al. 2007). Since marine 
mammals depend on acoustic cues for vital biological functions, such as 
orientation, communication, finding prey, and avoiding predators, 
marine mammals that suffer from PTS or TTS could have reduced fitness 
in survival and reproduction, either permanently or temporarily. 
Repeated noise exposure that leads to TTS could cause PTS.
    Measured source levels from impact pile driving can be as high as 
214 dB re 1 [mu]Pa @ 1 m. Although no marine mammals have been shown to 
experience TTS or PTS as a result of being exposed to pile driving 
activities, experiments on a bottlenose dolphin (Tursiops truncates) 
and beluga whale

[[Page 2374]]

(Delphinapterus leucas) showed that exposure to a single watergun 
impulse at a received level of 207 kPa (or 30 psi) peak-to-peak (p-p), 
which is equivalent to 228 dB (p-p) re 1 [mu]Pa, resulted in a 7 and 6 
dB TTS in the beluga whale at 0.4 and 30 kHz, respectively. Thresholds 
returned to within 2 dB of the pre-exposure level within 4 minutes of 
the exposure (Finneran et al. 2002). No TTS was observed in the 
bottlenose dolphin. Although the source level of pile driving from one 
hammer strike is expected to be much lower than the single watergun 
impulse cited here, animals being exposed for a prolonged period to 
repeated hammer strikes could receive more noise exposure in terms of 
SEL than from the single watergun impulse (estimated at 188 dB re 1 
[mu]Pa\2\-s) in the aforementioned experiment (Finneran et al. 2002).
    Noises from dismantling of marine foundations by mechanical means 
include, but are not limited to, saw cutting, mechanical splitting, 
drilling and pulverizing. Saw cutting and drilling constitute non-pulse 
noise, whereas mechanical splitting and pulverizing constitute impulse 
noise. Although the characteristics of these noises are not well 
studied, noises from saw cutting and drilling are expected to be 
similar to vibratory pile driving, and noises from mechanical splitting 
and pulverizing are expected to be similar to impact pile driving, but 
at lower intensity, due to the similar mechanisms in sound generating 
but at a lower power outputs. CALTRANS states that drilling and saw 
cutting are anticipated to produce underwater sound pressure levels 
(SPLs) in excess of 120 dB RMS, but are not anticipated to exceed the 
180 dB re 1 [mu]Pa (RMS). The mechanical splitting and pulverizing of 
concrete with equipment such as a hammer hoe has the potential to 
generate high sound pressure levels in excess of 190 dB re 1 [mu]Pa 
(RMS) at 1 m.
    However, in order for marine mammals to experience TTS or PTS, the 
animals have to be close enough to be exposed to high intensity noise 
levels for prolonged period of time. Based on the best scientific 
information available, these sound levels are far below the threshold 
that could cause TTS or the onset of PTS.
    In addition, chronic exposure to excessive, though not high-
intensity, noise could cause masking at particular frequencies for 
marine mammals that utilize sound for vital biological functions. 
Masking can interfere with detection of acoustic signals such as 
communication calls, echolocation sounds, and environmental sounds 
important to marine mammals. Therefore, under certain circumstances, 
marine mammals whose acoustical sensors or environment are being 
severely masked could also be impaired from maximizing their 
performance fitness in survival and reproduction.
    Masking occurs at the frequency band which the animals utilize. 
Therefore, since noise generated from in-water pile driving during the 
SF-OBB construction activities is mostly concentrated at low frequency 
ranges, it may have less effect on high frequency echolocation sounds 
by harbor porpoises. However, lower frequency man-made noises are more 
likely to affect detection of communication calls and other potentially 
important natural sounds such as surf and prey noise. It may also 
affect communication signals when they occur near the noise band and 
thus reduce the communication space of animals (e.g., Clark et al. 
2009) and cause increased stress levels (e.g., Foote et al. 2004; Holt 
et al. 2009).
    Unlike TS, masking can potentially impact the species at 
population, community, or even ecosystem levels, as well as individual 
levels. Masking affects both senders and receivers of the signals and 
could have long-term chronic effects on marine mammal species and 
populations. Recent science suggests that low frequency ambient sound 
levels have increased by as much as 20 dB (more than 3 times in terms 
of SPL) in the world's ocean from pre-industrial periods, and most of 
these increases are from distant shipping (Hildebrand 2009). All 
anthropogenic noise sources, such as those from vessels traffic, pile 
driving, dredging, and dismantling existing bridge by mechanic means, 
contribute to the elevated ambient noise levels, thus intensify 
masking.
    Nevertheless, the sum of noise from the proposed SF-OBB 
construction activities is confined in an area of inland waters (San 
Francisco Bay) that is bounded by landmass, therefore, the noise 
generated is not expected to contribute to increased ocean ambient 
noise. Due to shallow water depth near the Oakland shore, dredging 
activities are mainly used to create a barge access channel to 
dismantle the existing bridge. Therefore, underwater sound propagation 
from dredging is expected to be poor due to the extreme shallowness of 
the area to be dredged.
    Finally, exposure of marine mammals to certain sounds could lead to 
behavioral disturbance (Richardson et al. 1995), such as: Changing 
durations of surfacing and dives, number of blows per surfacing, or 
moving direction and/or speed; reduced/increased vocal activities, 
changing/cessation of certain behavioral activities (such as 
socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping), avoidance of 
areas where noise sources are located, and/or flight responses (e.g., 
pinnipeds flushing into water from haulouts or rookeries).
    The biological significance of many of these behavioral 
disturbances is difficult to predict, especially if the detected 
disturbances appear minor. However, the consequences of behavioral 
modification could be expected to be biologically significant if the 
change affects growth, survival, and reproduction. Some of these 
significant behavioral modifications include:
     Drastic change in diving/surfacing patterns (such as those 
thought to be causing beaked whale stranding due to exposure to 
military mid-frequency tactical sonar);
     Habitat abandonment due to loss of desirable acoustic 
environment; and
     Cessation of feeding or social interaction.
    For example, at the Guerreo Negro Lagoon in Baja California, 
Mexico, which is one of the important breeding grounds for Pacific gray 
whales, shipping and dredging associated with a salt works may have 
induced gray whales to abandon the area through most of the 1960s 
(Bryant et al. 1984). After these activities stopped, the lagoon was 
reoccupied, first by single whales and later by cow-calf pairs.
    The onset of behavioral disturbance from anthropogenic noise 
depends on both external factors (characteristics of noise sources and 
their paths) and the receiving animals (hearing, motivation, 
experience, demography) and is also difficult to predict (Southall et 
al. 2007).
    The proposed project area is not believed to be a prime habitat for 
marine mammals, nor is it considered an area frequented by marine 
mammals. Therefore, behavioral disturbances that could result from 
anthropogenic noise associated with SF-OBB construction activities are 
expected to affect only a small number of marine mammals on an 
infrequent basis.
    Currently NMFS uses 160 dB re 1 [mu]Pa (RMS) at received level for 
impulse noises (such as impact pile driving, mechanic splitting and 
pulverizing) as the onset of marine mammal behavioral harassment, and 
120 dB re 1 [mu]Pa (RMS) for non-impulse noises (vibratory pile 
driving, saw cutting, drilling, and dredging).
    As far as airborne noise is concerned, based on airborne noise 
levels measured and on-site monitoring conducted during 2004 under a 
previous IHA,

[[Page 2375]]

noise levels from the East Span project did not result in the 
harassment of harbor seals hauled out on Yerba Buena Island (YBI). 
Also, noise levels from the East Span project are not expected to 
result in harassment of the sea lions hauled out at Pier 39 as airborne 
and waterborne sound pressure levels (SPLs) would attenuate to levels 
below where harassment would be expected by the time they reach that 
haul-out site, 5.7 km (3.5 miles) from the project site. Therefore, no 
pinniped hauled out would be affected as a result of the proposed pile-
driving. A detailed description of the acoustic measurements is 
provided in the 2004 CALTRANS marine mammal and acoustic monitoring 
report for the same activity (CALTRANS' 2005).
    Short-term impacts to habitat may include minimal disturbance of 
the sediment where individual bridge piers are constructed. Long-term 
impacts to marine mammal habitat will be limited to the footprint of 
the piles and the obstruction they will create following installation. 
However, this impact is not considered significant as the marine 
mammals can easily swim around the piles of the new bridge, as they 
currently swim around the existing bridge piers.

Impact on Availability of Affected Species for Taking for Subsistence 
Uses

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

Mitigation Measures

    For the issuance of the IHA for the planned 2012-2013 SF-OBB 
construction activities to reduce adverse impacts to marine mammals to 
the lowest extent practicable, NMFS requires the following mitigation 
measures to be implemented.

Use of Noise Attenuation Devices

    To reduce impact on marine mammals, CALTRANS shall use marine pile 
driving energy attenuator (i.e., air bubble curtain system), or other 
equally effective sound attenuation method (e.g., dewatered cofferdam) 
for all impact pile driving, with the exception of pile proofing.

Establishment of Exclusion and Level B Harassment Zones

    Before the commencement of in-water construction activities, which 
include impact pile driving, vibratory pile driving, and mechanical 
dismantling of existing bridge, CALTRANS shall establish exclusion 
zones where received underwater sound pressure levels (SPLs) are higher 
than 180 dB (rms) and 190 dB (rms) re 1 [micro]Pa for cetaceans and 
pinnipeds, respectively, and Level B behavioral harassment zones where 
received underwater sound pressure levels (SPLs) are higher than 160 dB 
(rms) and 120 dB (rms) re 1 [micro]Pa for impulse noise sources (impact 
pile driving) and non-impulses noise sources (vibratory pile driving 
and mechanic dismantling), respectively. Before the sizes of actual 
zones are determined based on hydroacoustic measurements, CALTRANS 
shall establish these zones based on prior measurements conducted 
during SF-OBB constructions, as described in Table 1 of this document.
    Once the underwater acoustic measurements are conducted during 
initial test pile driving, CALTRANS shall adjust the size of the 
exclusion zones and Level B behavioral harassment zones, and monitor 
these zones accordingly.
    NMFS-approved protected species observers (PSOs) shall conduct 
initial survey of the safety zone to ensure that no marine mammals are 
seen within the zones before impact pile driving of a pile segment 
begins. If marine mammals are found within the safety zone, impact pile 
driving of the segment would be delayed until they move out of the 
area. If a marine mammal is seen above water and then dives below, the 
contractor would wait 15 minutes for pinnipeds and harbor porpoise and 
30 minutes for gray whales. If no marine mammals are seen by the 
observer in that time it would be assumed that the animal has moved 
beyond the safety zone. This 15-minute criterion is based on scientific 
evidence that harbor seals in San Francisco Bay dive for a mean time of 
0.50 minutes to 3.33 minutes (Harvey and Torok, 1994), and the mean 
diving duration for harbor porpoises ranges from 44 to 103 seconds 
(Westgate et al., 1995).
    Once the pile driving of a segment begins it cannot be stopped 
until that segment has reached its predetermined depth due to the 
nature of the sediments underlying the Bay. If pile driving stops and 
then resumes, it would potentially have to occur for a longer time and 
at increased energy levels. In sum, this would simply amplify impacts 
to marine mammals, as they would endure potentially higher SPLs for 
longer periods of time. Pile segment lengths and wall thickness have 
been specially designed so that when work is stopped between segments 
(but not during a single segment), the pile tip is never resting in 
highly resistant sediment layers. Therefore, because of this 
operational situation, if seals, sea lions, or harbor porpoises enter 
the safety zone after pile driving of a segment has begun, pile driving 
will continue and marine mammal observers will monitor and record 
marine mammal numbers and behavior. However, if pile driving of a 
segment ceases for 30 minutes or more and a marine mammal is sighted 
within the designated safety zone prior to commencement of pile 
driving, the observer(s) must notify the Resident Engineer (or other 
authorized individual) immediately and follow the mitigation 
requirements as outlined previously in this document.

Soft Start

    It should be recognized that although marine mammals will be 
protected from Level A harassment (i.e., injury) through marine mammal 
observers monitoring a 190-dB exclusion zone for pinnipeds and 180-dB 
exclusion zone for cetaceans, mitigation may not be 100 percent 
effective at all times in locating marine mammals. Therefore, in order 
to provide additional protection to marine mammals near the project 
area by allowing marine mammals to vacate the area prior to receiving a 
potential injury, CALTRANS and its contractor will also ``soft start'' 
the hammer prior to operating at full capacity. This should expose 
fewer animals to loud sounds both underwater and above water. This 
would also ensure that, although not expected, any pinnipeds and 
cetaceans that are missed during the initial exclusion zone monitoring 
will not be injured.

Power Down and Shut-Down

    As mentioned previously, although power down and shut-down measures 
will not be required for pile driving activities, these measures are 
required for mechanical dismantling of the existing bridge. The 
contractor perform mechanical dismantling work will stop in-water noise 
generating machinery when marine mammals are sighted within the 
designated exclusion zones.

Monitoring Measures

    The following monitoring measures are required for the proposed SF-
OBB construction activities.

Visual Monitoring

    Besides using mitigation measures as a mean of implementing power 
down and shut-down measures for mechanical bridge dismantling, marine 
mammal monitoring will also be conducted to assess potential impacts 
from CALTRANS construction activities. CALTRANS will implement onsite 
marine mammal monitoring for 100% of all unattenuated impact pile 
driving of H-piles for 180- and 190-dB re 1 [micro]Pa exclusion zones 
and 160-dB re 1 [micro]Pa

[[Page 2376]]

Level B harassment zone, attenuated impact pile driving (except pile 
proofing) and mechanical dismantling for 180- and 190-dB re 1 [micro]Pa 
exclusion zones. CALTRANS will also monitor 20% of the attenuated 
impact pile driving for the 160-dB re 1 [micro]Pa Level B harassment 
zone, and 20% of vibratory pile driving and mechanic dismantling for 
the 120-dB re 1 [micro]Pa Level B harassment zone.
    Monitoring of the pinniped and cetacean exclusion zones shall be 
conducted by a minimum of three qualified NMFS-approved protected 
species observers (PSOs). Observations will be made using high-quality 
binoculars (e.g., Zeiss, 10 x 42 power). PSOs will be equipped with 
radios or cell phones for maintaining contact with other observers and 
CALTRANS engineers, and range finders to determine distance to marine 
mammals, boats, buoys, and construction equipment.
    Data on all observations will be recorded and will include the 
following information:
    (1) Location of sighting;
    (2) Species;
    (3) Number of individuals;
    (4) Number of calves present;
    (5) Duration of sighting;
    (6) Behavior of marine animals sighted;
    (7) Direction of travel;
    (8) When in relation to construction activities did the sighting 
occur (e.g., before, ``soft-start'', during, or after the pile driving 
or removal).
    The reactions of marine mammals will be recorded based on the 
following classifications that are consistent with the Richmond Bridge 
Harbor Seal survey methodology (for information on the Richmond Bridge 
authorization, see 68 FR 66076, November 25, 2003): (1) No response, 
(2) head alert (looks toward the source of disturbance), (3) approach 
water (but not leave), and (4) flush (leaves haul-out site). The number 
of marine mammals under each disturbance reaction will be recorded, as 
well as the time when seals re-haul after a flush.

Hydroacoustic Monitoring

    The purpose of the underwater sound monitoring during dismantling 
of concrete foundations via mechanical means is to establish the 
exclusion zones of 180 dB re 1 [micro]Pa (rms) for cetaceans and 190 dB 
re 1 [micro]Pa (rms) for pinnipeds. Monitoring will occur during the 
initial use of concrete dismantling equipment with the potential to 
generate sound pressure levels in excess of 180 dB re 1 [micro]Pa 
(rms). Monitoring will likely be conducted from construction barges 
and/or boats. Measurements will be taken at various distances as needed 
to determine the distance to the 180 and 190 dB re 1 [micro]Pa (rms) 
contours.
    The purpose of underwater sound monitoring during impact pile 
driving will be to verify sound level estimates and confirm that sound 
levels do not equal or exceed 180 dB re 1 [micro]Pa (rms).

Reporting

    CALTRANS will notify NMFS prior to the initiation of the pile 
driving and dismantling activities for the removal of the existing east 
span. NMFS will be informed of the initial sound pressure level 
measurements for both pile driving and foundation dismantling 
activities, including the final exclusion zone and Level B harassment 
zone radii established for impact and vibratory pile driving and marine 
foundation dismantling activities.
    Monitoring reports will be posted on the SFOBB Project's biological 
mitigation Web site (www.biomitigation.org) on a weekly basis if in-
water construction activities are conducted. Marine mammal monitoring 
reports will include species and numbers of marine mammals observed, 
time and location of observation and behavior of the animal. In 
addition, the reports will include an estimate of the number and 
species of marine mammals that may have been harassed as a result of 
activities.
    In addition, CALTRANS will provide NMFS with a draft final report 
within 90 days after the expiration of the IHA. This report should 
detail the monitoring protocol, summarize the data recorded during 
monitoring, and estimate the number of marine mammals that may have 
been harassed due to pile driving. If no comments are received from 
NMFS within 30 days, the draft final report will constitute the final 
report. If comments are received, a final report must be submitted 
within 30 days after receipt of comments.

Marine Mammal Monitoring Report From Previous IHA

    As mentioned above, marine mammal monitoring during CALTRANS' pile 
driving activities and weekly marine mammal observation memorandums 
(CALTRANS 2007; 2010) indicate that only a small number of harbor seals 
(a total of 16 individuals since 2006) and 1 California sea lion (a 
total of 1 individual in 2009) were observed within ZOIs that could 
result in behavioral harassment. However, the reports state that none 
of the animals were observed as been startled by the exposure, which 
could be an indication that these animals were habituated to human 
activities in San Francisco Bay. In addition, no harbor porpoise or 
gray whales were observed during pile driving activities associated to 
CALTRANS' SF-OBB construction work.

Estimated Take by Incidental Harassment

    Marine mammal take estimates are based on marine mammal monitoring 
reports and marine mammal observations made during pile driving 
activities associated with the SF-OBB construction work authorized 
under prior IHAs. For pile driving activities conducted in 2006, 5 
harbor seals and no other marine mammals were detected within the 
isopleths of 160 dB (rms) re 1 [micro]Pa during impact pile driving 
where air bubble curtains were deployed for mitigation measures (radius 
of zone of influence (ZOI) at 500 m) (CALTRANS 2007). For pile driving 
activities conducted in the 2008 and 2009 seasons, CALTRANS monitored a 
much larger ZOI of 120 dB (rms) re 1 [micro]Pa as a result of vibratory 
pile driving. A total of 11 harbor seals and 1 California sea lion were 
observed entering the 120 dB (rms) re 1 [micro]Pa ZOI (CALTRANS). 
However, despite the ZOI being monitored extended to 1,900 m for the 
120 dB isopleths, CALTRANS did not specify which pile driving 
activities conducted in 2008 and 2009 used an impact hammer and which 
ones used a vibratory hammer. Therefore, at least some of these animals 
were not exposed to received level above 160 dB (rms) re [micro]Pa, and 
thus should not be considered as ``taken'' under the MMPA. No harbor 
porpoise or gray whales were observed during pile driving activities 
associated to CALTRANS' SF-OBB construction work (CALTRANS 2007; 2010).
    Based on these results, and accounting for a certain level of 
uncertainty regarding the next phase of construction (which will 
include dismantling of the existing bridge by mechanical means), NMFS 
concludes that at maximum 50 harbor seals, 10 California sea lions, 10 
harbor porpoises, and 5 gray whales could be exposed to noise levels 
that could cause Level B harassment as a result of the CALTRAN' SF-OBB 
construction activities.

Negligible Impact and Small Numbers Analyses and Determinations

    Pursuant to NMFS' regulations implementing the MMPA, an applicant 
is required to estimate the number of animals that will be ``taken'' by 
the specified activities (i.e., takes by

[[Page 2377]]

harassment only, or takes by harassment, injury, and/or death). This 
estimate informs the analysis that NMFS must perform to determine 
whether the activity will have a ``negligible impact'' on the species 
or stock. Level B (behavioral) harassment occurs at the level of the 
individual(s) and does not assume any resulting population-level 
consequences, though there are known avenues through which behavioral 
disturbance of individuals can result in population-level effects. A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of recruitment or survival (i.e., population-
level effects). An estimate of the number of Level B harassment takes 
alone is not enough information on which to base an impact 
determination.
    In addition to considering estimates of the number of marine 
mammals that might be ``taken'' through behavioral harassment, NMFS 
considers other factors, such as the likely nature of any responses 
(their intensity, duration, etc.), the context of any responses 
(critical reproductive time or location, migration, etc.), as well as 
the number and nature of estimated Level A takes, the number of 
estimated mortalities, and effects on habitat.
    The CALTRANS' specified activities have been described based on 
best estimates of the planned SF-OBB construction project within the 
proposed project area. Some of the noises that would be generated as a 
result of the proposed bridge construction and dismantling project, 
such as impact pile driving, are high intensity. However, the in-water 
pile driving for the piles would use small hammers and/or vibratory 
pile driving methods, coupled with noise attenuation mechanism such as 
air bubble curtains for impact pile driving, therefore the resulting 
exclusion zones for potential TS are expected to be extremely small (< 
35 m) from the hammer. In addition, the source levels from vibratory 
pile driving are expected to be below the TS onset threshold. 
Therefore, NMFS does not expect that any animals would receive Level A 
(including injury) harassment or Level B harassment in the form of TTS 
from being exposed to in-water pile driving associated with SF-OBB 
construction project.
    Based on marine mammal monitoring reports under previous IHAs, only 
16 harbor seals and 1 California sea lion were observed within the 120 
dB (in 2008 and 2009) or 160 dB (in 2006) ZOIs during in-water pile 
driving since 2006. NMFS estimates that up to 50 harbor seals, 10 
California sea lions, 10 harbor porpoises, and 5 gray whales could be 
exposed to received levels above 120 dB (rms) during vibratory pile 
driving or 160 dB (rms) during impact pile driving for the next season 
of construction activities due to the large numbers of piles to be 
driven and the extended zones of influence from vibratory pile driving. 
These are small numbers, representing 0.15% of the California stock of 
harbor seal population (estimated at 34,233; Carretta et al. 2010), 
0.00% of the U.S. stock of California sea lion population (estimated at 
238,000; Carretta et al. 2010), 0.10% of the San Francisco-Russian 
River stock of harbor porpoise population (estimated at 9,181; Carretta 
et al. 2010), and 0.05% of the Eastern North Pacific stock of gray 
whale population (Allen and Angliss 2010).
    Animals exposed to construction noise associated with the SF-OBB 
construction work would be limited to Level B behavioral harassment 
only, i.e., the exposure of received levels for impulse noise between 
160 and 180 dB (rms) re 1 [mu]Pa (from impact pile driving) and for 
non-impulse noise between 120 and 180 dB (rms) re 1 [mu]Pa (from 
vibratory pile driving). In addition, the potential behavioral 
responses from exposed animals are expected to be localized and short 
in duration.
    These low intensity, localized, and short-term noise exposures 
(i.e., 160 dB re 1 [mu]Pa (rms) from impulse sources and 120 dB re 1 
[mu]Pa (rms) from non-impulse sources), are expected to cause brief 
startle reactions or short-term behavioral modification by the animals. 
These brief reactions and behavioral changes are expected to disappear 
when the exposures cease. Therefore, these levels of received 
underwater construction noise from the proposed SF-OBB construction 
project are not expected to affect marine mammal annual rates of 
recruitment or survival. The maximum estimated 160 dB isopleths from 
impact pile driving is 500 m from the pile, and the estimated 120 dB 
maximum isopleths from vibratory pile driving is approximately 2,000 m 
from the pile. There is no pinniped haul-out area in the vicinity of 
the pile driving sites.
    For the reasons discussed in this document, NMFS has determined 
that the impact of in-water pile driving associated with construction 
of the SF-OBB would result, at worst, in the Level B harassment of 
small numbers of California sea lions, Pacific harbor seals, harbor 
porpoises, and potentially gray whales that inhabit or visit SFB in 
general and the vicinity of the SF-OBB in particular. While behavioral 
modifications, including temporarily vacating the area around the 
construction site, may be made by these species to avoid the resultant 
visual and acoustic disturbance, the availability of alternate areas 
within SFB and haul-out sites (including pupping sites) and feeding 
areas within the Bay has led NMFS to determine that this action will 
have a negligible impact on California sea lion, Pacific harbor seal, 
harbor porpoise, and gray whale populations along the California coast.
    In addition, no take by Level A harassment (injury) or death is 
anticipated and harassment takes should be at the lowest level 
practicable due to incorporation of the mitigation measures mentioned 
previously in this document.

National Environmental Policy Act (NEPA)

    NMFS prepared an Environmental Assessment (EA) for the take of 
marine mammals incidental to construction of the East Span of the SF-
OBB and made a Finding of No Significant Impact (FONSI) on November 4, 
2003. Due to the modification of part of the construction project and 
the mitigation measures, NMFS reviewed additional information from 
CALTRANS regarding empirical measurements of pile driving noises for 
the smaller temporary piles without an air bubble curtain system and 
the use of vibratory pile driving. NMFS prepared a Supplemental 
Environmental Assessment (SEA) and analyzed the potential impacts to 
marine mammals that would result from the modification of the action. A 
Finding of No Significant Impact (FONSI) was signed on August 5, 2009. 
A copy of the SEA and FONSI is available upon request (see ADDRESSES).

Endangered Species Act (ESA)

    NMFS has determined that issuance of the IHA will have no effect on 
listed marine mammals, as none are known to occur in the action area.

Authorization

    NMFS has issued an IHA to CALTRANS for the potential harassment of 
small numbers of harbor seals, California sea lions, harbor porpoises, 
and gray whales incidental to construction of a replacement bridge for 
the East Span of the San Francisco-Oakland Bay Bridge in California, 
provided the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated.

    Dated: January 7, 2013.
Helen M. Golde,
Acting Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2013-00381 Filed 1-10-13; 8:45 am]
BILLING CODE 3510-22-P