[Federal Register Volume 81, Number 190 (Friday, September 30, 2016)]
[Notices]
[Pages 67313-67326]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2016-23602]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XE671


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; issuance of an incidental harassment authorization.

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SUMMARY: In accordance with the regulations implementing the Marine 
Mammal Protection Act (MMPA) as amended, notification is hereby given 
that we have issued an incidental harassment authorization (IHA) to 
California Department of Transportation (CALTRANS) to incidentally 
harass, by Level B harassment only, seven species of marine mammals 
during activities associated with the East Span of the San Francisco-
Oakland Bay Bridge (SFOBB) in the San Francisco Bay (SFB), California.

DATES: This authorization is effective from September 19, 2016 through 
September 18, 2017.

FOR FURTHER INFORMATION CONTACT: Shane Guan, Office of Protected 
Resources, NMFS, (301) 427-8401.

SUPPLEMENTARY INFORMATION: 

Background

    Sections 101(a)(5)(A) and (D) of the MMPA (16 U.S.C. 1361 et seq.) 
direct the Secretary of Commerce to allow, upon request, the 
incidental, but not intentional, taking of small numbers of marine 
mammals by U.S. citizens who engage in a specified activity (other than 
commercial fishing) within a specified geographical region if certain 
findings are made and either regulations are issued or, if the taking 
is limited to harassment, a notice of a proposed authorization is 
provided to the public for review.
    An authorization for incidental takings shall be granted if NMFS 
finds that the taking will have a negligible impact on the species or 
stock(s), will not have an unmitigable adverse impact on the 
availability of the species or stock(s) for subsistence uses (where 
relevant), and if the permissible methods of taking and requirements 
pertaining to the mitigation, monitoring and reporting of such takings 
are set forth. NMFS has defined ``negligible impact'' in 50 CFR 216.103 
as ``. . . an impact resulting from the specified activity that cannot 
be reasonably expected to, and is not reasonably likely to, adversely 
affect the species or stock through effects on annual rates of 
recruitment or survival.''
    Section 101(a)(5)(D) of the MMPA established an expedited process 
by which citizens of the U.S. can apply for a one-year authorization to 
incidentally take small numbers of marine mammals by harassment, 
provided that there is no potential for serious injury or mortality to 
result from the activity. 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.

Summary of Request

    On March 11, 2016, CALTRANS submitted a request to NMFS for the 
potential harassment of a small number of marine mammals incidental to 
the dismantling of the East Span of the original SFOBB in SFB, 
California, between July 16, 2016, and July 15, 2017. On May 16, 2016, 
CALTRANS submitted a revision of its IHA application based on NMFS 
comments. NMFS determined that the IHA application was complete on May 
19, 2016.

Description of the Specified Activity

    CALTRANS proposes removal of the East Span of the original SFOBB by 
mechanical dismantling and by use of controlled charges to implode the 
pier into its open cellular chambers below mudline. Activities 
associated with dismantling the original East Span potentially may 
result in incidental take of marine mammals. These activities include 
vibratory pile driving, vibratory pile extraction/removal, impact pile 
driving, and the use of highly controlled charges to dismantle the Pier 
E4 and Pier E5 marine foundations.
    A one-year IHA was previously issued to CALTRANS for pile driving/
removal and mechanical dismantling activities on July 17, 2015 (80 FR 
43710; July 23, 2015), based on activities described on CALTRANS' IHA 
application dated April 13, 2013. This IHA is valid until July 16, 
2016. On September 9, 2015, NMFS issued another IHA to CALTRANS for 
demolition of Pier E3 of the original SFOBB by highly controlled 
explosives (80 FR 57584; September 24, 2015). This IHA expired on 
December 30, 2015. Since the construction activities related with the 
original SFOBB dismantling will last for another two years, CALTRANS is 
requesting an IHA that covers take of marine mammals from both pile 
driving/removal and confined explosion.
    Construction activities for the replacement of the SFOBB east span 
commenced in 2002 and are expected to be completed in 2016 with the 
completion of the bike/pedestrian path and eastbound on ramp from Yerba 
Buena Island. The new east span is now open to traffic. On November 10, 
2003, NMFS issued the first project-related IHA to CALTRANS, 
authorizing the take of small numbers of marine mammals incidental to 
the construction of the SFOBB Project. Over the years, CALTRANS has 
been issued a total of nine IHAs for the SFOBB Project to date, 
excluding the application currently under review.
    The demolition of Piers E4 and E5 through controlled implosion are 
planned to occur in October, November, or December 2016, and pile 
driving and pile removal activities may occur at any time of the year.
    The SFOBB project area is located in the central San Francisco Bay 
(SFB or Bay), between Yerba Buena Island (YBI) and the city of Oakland. 
The western limit of the project area is the east portal of the YBI 
tunnel, located in the city of San Francisco. The eastern limit of the 
project area is located approximately 1,312 ft (400 m) west of the Bay 
Bridge toll plaza, where the new and former spans connect with land at 
the Oakland Touchdown in the city of Oakland. Detailed description of 
CALTRANS East Span Removal Project is provided in the Federal Register 
notice for the proposed IHA (81 FR 48745; July 24, 2016). No changes 
have been made since the

[[Page 67314]]

publication of that notice. A summary of CALTRANS activities is 
provided below.

1. Vibratory and Impact Driving of Temporary Piles

    CALTRANS anticipates temporary access trestles, in-water falsework, 
and cofferdams may be required to dismantle the existing bridge. 
Temporary access trestles, supported by temporary marine piles, and 
cofferdams may be needed to provide construction access. CALTRANS 
estimates that a maximum of 200 temporary piles may be installed during 
the 1-year period of IHA coverage. Types of temporary piles to be 
installed may include sheet piles, 14-in (0.34-m) H-piles, and steel 
pipe piles, equal to or less than 36-in (0.91-m) in diameter. A maximum 
of 132 days of pile driving may be required to install and/or remove 
piles during the one-year period of IHA coverage.

2. Removal of Piers E4 and E5

    CALTRANS proposes the removal of Piers E4 and E5 of the original 
East Span by use of controlled charges to implode each pier into its 
open cellular chambers below the mudline. A Blast Attenuation System 
(BAS) will be used to minimize potential impacts on biological 
resources in the Bay. Both NMFS and CALTRANS believe that the results 
from the Pier E3 Demonstration Project support the use of controlled 
charges as a more expedient method of removal that will cause less 
environmental impact as compared to approved mechanical methods using a 
dry (fully dewatered) cofferdam.
    Piers E4 and E5 of the original East Span are located between the 
OTD area and YBI, and just south of the SFOBB new East Span. These 
piers are concrete cellular structures that occupy areas deep below the 
mudline, within the water column, and above the water line of the Bay.

Comments and Responses

    A notice of NMFS' proposal to issue an IHA was published in the 
Federal Register on July 24, 2016 (81 FR 48745). During the 30-day 
public comment period, NMFS received a comment letter from the Marine 
Mammal Commission (Commission). Specific comments and responses are 
provided below.
    Comment 1: The Commission states that the method used to estimate 
the numbers of takes, which sums fractions of takes for each species 
across days, does not account for NMFS's 24-hour reset policy. The 
Commission states that instead of summing fractions of takes across 
days and then rounding to estimate total takes, NMFS should have 
calculated a daily take estimate (determined by multiplying the 
estimated density of marine mammals in the area by the daily ensonified 
area) and then rounding that to a whole number before multiplying it by 
the number of days that activities would occur. Thus, the Commission 
recommends that NMFS (1) follow its policy of a 24-hour reset for 
enumerating the number of each species that could be taken, (2) apply 
standard rounding rules before summing the numbers of estimated takes 
across days, and (3) for species that have the potential to be taken 
but model-estimated or calculated takes round to zero, use group size 
to inform the take estimates--these methods should be used consistently 
for all future incidental take authorizations.
    Response: While for certain projects NMFS has rounded to the whole 
number for daily takes, the circumstance for projects like this one 
when the objective of take estimation is to provide more accurate 
assessments for potential impacts to marine mammals for the entire 
project, the rounding in the middle of calculation will introduce large 
errors into the process. In addition, while NMFS uses a 24-hour reset 
for its take calculation to ensure that individual animals are not 
counted as a take more than once per day, that fact does not make the 
calculation of take across the entire activity period inherently 
incorrect. There is no need for daily (24-hour) rounding in this case 
because there is no daily limit of takes, so long as total authorized 
takes of marine mammal are not exceeded. In short, the calculation of 
predicted take is not an exact science and there are arguments for 
taking different mathematical approaches in different situations, and 
for making qualitative adjustments in other situations. NMFS is 
currently engaged in developing a protocol to guide more consistent 
take calculation given certain circumstances. We believe, however, that 
the prediction for this action remains appropriate.
    Comment 2: The Commission notes that in the proposed IHA NMFS would 
require protected species observers (PSOs) to implement 100 percent 
monitoring for Level A harassment zones of all pile driving, but only 
20 percent monitoring for Level B harassment zones for vibratory pile 
driving and removal. The Commission recommends that NMFS require 
CALTRANS to implement full-time monitoring of Level A and B harassment 
zones during all pile driving and pile removal activities.
    Response: NMFS agrees with the Commission's recommendation, and 
discussed it with CALTRANS. CALTRANS agrees that 100 percent monitoring 
is feasible and will conduct visual monitoring for all pile driving and 
pile removal activities. The IHA issued to CALTRANS includes such 
measures.

Description of Marine Mammals in the Area of the Specified Activity

    Seven species of marine mammals regularly inhabit or rarely or 
seasonally enter the San Francisco Bay (Table 1). The two most common 
species observed are the Pacific harbor seal (Phoca vitulina richardii) 
and the California sea lion (Zalophus californianus). Juvenile northern 
elephant seals (Mirounga angustirostris) seasonally enter the Bay 
(spring and fall), while harbor porpoises (Phocoena phocoena) may enter 
the western side of the Bay throughout the year, but rarely occur near 
the SFOBB east span. Gray whales (Eschrichtius robustus) may enter the 
Bay during their northward migration in the late winter and spring. In 
addition, though rare, northern fur seals (Callorhinus ursinus) and 
bottlenose dolphins (Tursiops truncatus) have also been sighted in the 
Bay. None of these species are listed as endangered or threatened under 
the Endangered Species Act (ESA), or as depleted or a strategic stock 
under the MMPA.

                                        Table 1--Marine Mammal Species Potentially Present in Region of Activity
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           Common name                Scientific name        Status          Occurrence            Seasonality              Range            Abundance
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Harbor seal......................  Phoca vitulina        .............  Common..............  Year round..........  California..........          30,968
                                    richardii.
California sea lion..............  Zalophus              .............  Common..............  Year round..........  California..........         296,750
                                    californianus.
Northern fur seal................  Callorhinus ursinus.  .............  Rare................  Year round..........  California..........          12,844
Northern elephant seal...........  Mirounga              .............  Occasional..........  Spring & fall.......  California..........         179,000
                                    angustirostris.
Gray whale.......................  Eschrichtius          (*)..........  Rare................  Spring & fall.......  Mexico to the U.S.            20,990
                                    robustus.                                                                        Arctic Ocean.

[[Page 67315]]

 
Harbor porpoise..................  Phocoena phocoena...  .............  Rare................  Year round..........  California..........           9,886
Coastal Bottlenose dolphin.......  Tursiops truncatus..  .............  Rare................  Year round..........  California..........             323
--------------------------------------------------------------------------------------------------------------------------------------------------------
* The E. North Pacific population is not listed under the ESA.

    More detailed information on the marine mammal species found in the 
vicinity of the SFOBB construction site can be found in CALTRANS IHA 
application, and in NMFS stock assessment report (Caretta et al., 
2015), which is available at the following URL: http://www.nmfs.noaa.gov/pr/sars/pdf/pacific_sars_2014_final_noaa_swfsc_tm_549.pdf. Refer to these documents 
for additional information on these species.

Potential Effects of the Specified Activity on Marine Mammals

    This section includes a summary and discussion of the ways that the 
types of stressors associated with the specified activity (e.g., pile 
removal and pile driving) have been observed to impact marine mammals. 
This discussion may also include reactions that we consider to rise to 
the level of a take and those that we do not consider to rise to the 
level of a take (for example, with acoustics, we may include a 
discussion of studies that showed animals not reacting at all to sound 
or exhibiting barely measurable avoidance). This section is intended as 
a background of potential effects and does not consider either the 
specific manner in which this activity will be carried out or the 
mitigation that will be implemented, and how either of those will shape 
the anticipated impacts from this specific activity. The ``Estimated 
Take by Incidental Harassment'' section later in this document will 
include a quantitative analysis of the number of individuals that are 
expected to be taken by this activity. The ``Analysis and 
Determinations'' section will include the analysis of how this specific 
activity will impact marine mammals and will consider the content of 
this section, the ``Estimated Take by Incidental Harassment'' section, 
the ``Mitigation'' section, and the ``Anticipated Effects on Marine 
Mammal Habitat'' section to draw conclusions regarding the likely 
impacts of this activity on the reproductive success or survivorship of 
individuals and from that on the affected marine mammal populations or 
stocks.
    When considering the influence of various kinds of sound on the 
marine environment, it is necessary to understand that different kinds 
of marine life are sensitive to different frequencies of sound. Based 
on available behavioral data, audiograms have been derived using 
auditory evoked potentials, anatomical modeling, and other data, NMFS 
(2016) designate ``marine mammal hearing groups'' for marine mammals 
and estimate the lower and upper frequencies of hearing of the groups. 
The marine mammal groups and the associated frequencies are indicated 
below (though animals are less sensitive to sounds at the outer edge of 
their functional range and most sensitive to sounds of frequencies 
within a smaller range somewhere in the middle of their hearing range):
     Low frequency cetaceans (13 species of mysticetes): 
Functional hearing is estimated to occur between approximately 7 hertz 
(Hz) and 35 kilohertz (kHz);
     Mid-frequency cetaceans (32 species of dolphins, seven 
species of larger toothed whales, and 19 species of beaked and 
bottlenose whales): Functional hearing is estimated to occur between 
approximately 150 Hz and 160 kHz;
     High frequency cetaceans (eight species of true porpoises, 
seven species of river dolphins, Kogia, the franciscana, and four 
species of cephalorhynchids): Functional hearing is estimated to occur 
between approximately 275 Hz and 160 kHz;
     Phocid pinnipeds in Water: Functional hearing is estimated 
to occur between approximately 50 Hz and 86 kHz; and
     Otariid pinnipeds in Water: Functional hearing is 
estimated to occur between approximately 60 Hz and 39 kHz.
    As mentioned previously in this document, seven marine mammal 
species (three cetacean and four pinniped species) are likely to occur 
in the vicinity of the SFOBB pile driving/removal and controlled pier 
detonation area. Of the two cetacean species, one belongs to low-
frequency cetacean (gray whale), one mid-frequency cetacean (bottlenose 
dolphin), and one high-frequency cetacean (harbor porpoise). two 
species of pinniped are phocid (Pacific harbor seal and northern 
elephant seal), and two species of pinniped is otariid (California sea 
lion and northern fur seal). A species' functional hearing group is a 
consideration when we analyze the effects of exposure to sound on 
marine mammals.

Potential Effects From In-Water Pile Driving and Pile Removal

    The CALTRANS SFOBB construction work using in-water pile driving 
and pile removal could adversely affect marine mammal species and 
stocks by exposing them to elevated noise levels in the vicinity of the 
activity area.
    Exposure to high intensity sound for a sufficient duration may 
result in auditory effects such as a noise-induced threshold shift--an 
increase in the auditory threshold after exposure to noise (Finneran et 
al., 2005). Factors that influence the amount of threshold shift 
include the amplitude, duration, frequency content, temporal pattern, 
and energy distribution of noise exposure. The magnitude of hearing 
threshold shift normally decreases over time following cessation of the 
noise exposure. The amount of threshold shift just after exposure is 
the initial threshold shift. If the threshold shift eventually returns 
to zero (i.e., the threshold returns to the pre-exposure value), it is 
a temporary threshold shift (Southall et al., 2007).
    Threshold Shift (noise-induced loss of hearing)--When animals 
exhibit reduced hearing sensitivity (i.e., sounds must be louder for an 
animal to detect them) following exposure to an intense sound or sound 
for long duration, it is referred to as a noise-induced threshold shift 
(TS). An animal can experience temporary threshold shift (TTS) or 
permanent threshold shift (PTS). TTS can last from minutes or hours to 
days (i.e., there is complete recovery), can occur in specific 
frequency ranges (i.e., an animal might only have a temporary loss of 
hearing sensitivity between the frequencies of 1 and 10 kHz), and can 
be of varying amounts (for example, an animal's hearing sensitivity 
might be reduced initially by only 6 decibel (dB) or reduced by 30 dB). 
PTS is permanent, but some recovery is possible. PTS can also occur in 
a specific frequency range and amount as mentioned above for TTS.

[[Page 67316]]

    For marine mammals, published data are limited to the captive 
bottlenose dolphin, beluga, harbor porpoise, and Yangtze finless 
porpoise (Finneran et al., 2000, 2002, 2003, 2005, 2007, 2010a, 2010b; 
Finneran and Schlundt, 2010; Lucke et al., 2009; Mooney et al., 2009a, 
2009b; Popov et al., 2011a, 2011b; Kastelein et al., 2012a; Schlundt et 
al., 2000; Nachtigall et al., 2003, 2004). For pinnipeds in water, data 
are limited to measurements of TTS in harbor seals, an elephant seal, 
and California sea lions (Kastak et al., 1999, 2005; Kastelein et al., 
2012b).
    Lucke et al. (2009) found a threshold shift (TS) of a harbor 
porpoise after exposing it to airgun noise with a received sound 
pressure level (SPL) at 200.2 dB (peak-to-peak) re: 1 micropascal 
([mu]Pa), which corresponds to a sound exposure level of 164.5 dB re: 1 
[mu]Pa\2\ s after integrating exposure. NMFS currently uses the root-
mean-square (rms) of received SPL at 180 dB and 190 dB re: 1 [mu]Pa as 
the threshold above which permanent threshold shift (PTS) could occur 
for cetaceans and pinnipeds, respectively. Because the airgun noise is 
a broadband impulse, one cannot directly determine the equivalent of 
rms SPL from the reported peak-to-peak SPLs. However, applying a 
conservative conversion factor of 16 dB for broadband signals from 
seismic surveys (McCauley, et al., 2000) to correct for the difference 
between peak-to-peak levels reported in Lucke et al. (2009) and rms 
SPLs, the rms SPL for TTS would be approximately 184 dB re: 1 [mu]Pa, 
and the received levels associated with PTS (Level A harassment) would 
be higher. This is still above NMFS' current 180 dB rms re: 1 [mu]Pa 
threshold for injury. However, NMFS recognizes that TTS of harbor 
porpoises is lower than other cetacean species empirically tested 
(Finneran & Schlundt, 2010; Finneran et al., 2002; Kastelein and 
Jennings, 2012).
    Marine mammal hearing plays a critical role in communication with 
conspecifics, and interpretation of environmental cues for purposes 
such as predator avoidance and prey capture. Depending on the degree 
(elevation of threshold in dB), duration (i.e., recovery time), and 
frequency range of TTS, and the context in which it is experienced, TTS 
can have effects on marine mammals ranging from discountable to serious 
(similar to those discussed in auditory masking, below). For example, a 
marine mammal may be able to readily compensate for a brief, relatively 
small amount of TTS in a non-critical frequency range that occurs 
during a time where ambient noise is lower and there are not as many 
competing sounds present. Alternatively, a larger amount and longer 
duration of TTS sustained during time when communication is critical 
for successful mother/calf interactions could have more serious 
impacts. Also, depending on the degree and frequency range, the effects 
of PTS on an animal could range in severity, although it is considered 
generally more serious because it is a permanent condition. Of note, 
reduced hearing sensitivity as a simple function of aging has been 
observed in marine mammals, as well as humans and other taxa (Southall 
et al., 2007), so one can infer that strategies exist for coping with 
this condition to some degree, though likely not without cost.
    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 (Clark 
et al., 2009). Acoustic masking is when other noises such as from human 
sources interfere with animal 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 that the animals utilize. 
Therefore, since noise generated from vessels dynamic positioning 
activity is mostly concentrated at low frequency ranges, it may have 
less effect on high frequency echolocation sounds by odontocetes 
(toothed whales). 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, which can occur over large temporal and spatial 
scales, can potentially affect 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 three times in terms of sound pressure 
level) in the world's ocean from pre-industrial periods, and most of 
these increases are from distant shipping (Hildebrand 2009). For 
CALTRANS' SFOBB construction activities, noises from vibratory pile 
driving contribute to the elevated ambient noise levels in the project 
area, thus increasing potential for or severity of masking. Baseline 
ambient noise levels in the Bay are very high due to ongoing shipping, 
construction and other activities in the Bay.
    Finally, marine mammals' exposure 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 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). Currently NMFS uses a received level of 160 dB re 1 [mu]Pa 
(rms) to predict the onset of behavioral harassment from impulse noises 
(such as impact pile driving), and 120 dB re 1 [mu]Pa (rms) for 
continuous noises (such as vibratory pile driving). For the CALTRANS 
SFOBB construction activities, both of these noise levels are 
considered for effects analysis because CALTRANS plans to use both 
impact and vibratory pile driving, as well as vibratory pile removal.
    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 biologically significant if the change affects 
growth, survival, and/or reproduction, which depends on the severity, 
duration, and context of the effects.

Potential Effects From Controlled Pier Implosion

    It is expected that an intense impulse from the Piers E4 and E5 
controlled implosion would have the potential to impact marine mammals 
in the vicinity. The majority of impacts would be startle behavior and 
temporary behavioral modification from marine mammals.

[[Page 67317]]

However, a few individual animals could be exposed to sound levels that 
would cause TTS.
    The underwater explosion would send a shock wave and blast noise 
through the water, release gaseous by-products, create an oscillating 
bubble, and cause a plume of water to shoot up from the water surface. 
The shock wave and blast noise are of most concern to marine animals. 
The effects of an underwater explosion on a marine mammal depends on 
many factors, including the size, type, and depth of both the animal 
and the explosive charge; the depth of the water column; and the 
standoff distance between the charge and the animal, as well as the 
sound propagation properties of the environment. Potential impacts can 
range from brief effects (such as behavioral disturbance), tactile 
perception, physical discomfort, slight injury of the internal organs 
and the auditory system, to death of the animal (Yelverton et al., 
1973; DoN, 2001). Non-lethal injury includes slight injury to internal 
organs and the auditory system; however, delayed lethality can be a 
result of individual or cumulative sublethal injuries (DoN, 2001). 
Immediate lethal injury would be a result of massive combined trauma to 
internal organs as a direct result of proximity to the point of 
detonation (DoN, 2001). Generally, the higher the level of impulse and 
pressure level exposure, the more severe the impact to an individual.
    Injuries resulting from a shock wave take place at boundaries 
between tissues of different density. Different velocities are imparted 
to tissues of different densities, and this can lead to their physical 
disruption. Blast effects are greatest at the gas-liquid interface 
(Landsberg 2000). Gas-containing organs, particularly the lungs and 
gastrointestinal tract, are especially susceptible (Goertner 1982; Hill 
1978; Yelverton et al., 1973). In addition, gas-containing organs 
including the nasal sacs, larynx, pharynx, trachea, and lungs may be 
damaged by compression/expansion caused by the oscillations of the 
blast gas bubble. Intestinal walls can bruise or rupture, with 
subsequent hemorrhage and escape of gut contents into the body cavity. 
Less severe gastrointestinal tract injuries include contusions, 
petechiae (small red or purple spots caused by bleeding in the skin), 
and slight hemorrhaging (Yelverton et al., 1973).
    Because the ears are the most sensitive to pressure, they are the 
organs most sensitive to injury (Ketten 2000). Sound-related damage 
associated with blast noise can be theoretically distinct from injury 
from the shock wave, particularly farther from the explosion. If an 
animal is able to hear a noise, at some level it can damage its hearing 
by causing decreased sensitivity (Ketten 1995). Sound-related trauma 
can be lethal or sublethal. Lethal impacts are those that result in 
immediate death or serious debilitation in or near an intense source 
and are not, technically, pure acoustic trauma (Ketten 1995). Sublethal 
impacts include hearing loss, which is caused by exposures to 
perceptible sounds. Severe damage (from the shock wave) to the ears 
includes tympanic membrane rupture, fracture of the ossicles, damage to 
the cochlea, hemorrhage, and cerebrospinal fluid leakage into the 
middle ear. Moderate injury implies partial hearing loss due to 
tympanic membrane rupture and blood in the middle ear. Permanent 
hearing loss also can occur when the hair cells are damaged by one very 
loud event, as well as by prolonged exposure to a loud noise or chronic 
exposure to noise. The level of impact from blasts depends on both an 
animal's location and, at outer zones, on its sensitivity to the 
residual noise (Ketten 1995).
    However, the above discussion concerning underwater explosion only 
pertains to open water detonation in a free field. CALTRANS' Pier E4 
and E5 demolition project using controlled implosion uses a confined 
detonation method, meaning that the charges would be placed within the 
structure. Therefore, most energy from the explosive shock wave would 
be absorbed through the destruction of the structure itself, and would 
not propagate through the open water. Measurements and modeling from 
confined underwater detonation for structure removal showed that energy 
from shock waves and noise impulses were greatly reduced in the water 
column (Hempen et al., 2007; CALTRANS 2016). Therefore, with monitoring 
and mitigation measures discussed above, CALTRANS Pier E4 and E5 
controlled implosions are not likely to cause injury or mortality to 
marine mammals in the project vicinity. Instead, NMFS believes that 
CALTRANS' Pier E4 and E5 controlled implosions in the San Francisco Bay 
are most like to cause Level B behavioral harassment and maybe TTS in a 
few individual of marine mammals, as discussed below.
    Changes in marine mammal behavior are expected to result from an 
acute stress response. This expectation is based on the idea that some 
sort of physiological trigger must exist to change any behavior that is 
already being performed. The exception to this rule is the case of 
auditory masking, which is not likely since the CALTRANS' controlled 
implosion is only two short, sequential detonations that last for 
approximately 3-4 seconds.

Potential Effects on Marine Mammal Habitat

    The removal of the SFOBB East Span is not likely to negatively 
affect the habitat of marine mammal populations because no permanent 
loss of habitat will occur, and only a minor, temporary modification of 
habitat will occur. The original SFOBB area is not used as a haul-out 
site by pinnipeds or as a major foraging area. Therefore, demolition of 
the concrete marine foundations and pile installation and removal 
activities are unlikely to permanently decrease fish populations in the 
area and are unlikely to affect marine mammal populations.
    Project activities will not affect any pinniped haul-out sites or 
pupping sites. The YBI harbor seal haul-out site is on the opposite 
site of the island from the SFOBB Project area. Because of the distance 
and the island blocking the sound, underwater noise and pressure levels 
from the SFOBB Project will not reach the haul-out. Other haul-out 
sites for sea lions and harbor seals are at a sufficient distance from 
the SFOBB Project area that they will not be affected. The closest 
recognized harbor seal pupping site is at Castro Rocks, approximately 
8.7 mi (14 km) from the SFOBB Project area. No sea lion rookeries are 
found in the Bay.
    The addition of underwater sound from SFOBB Project activities to 
background noise levels can constitute a potential cumulative impact on 
marine mammals. However, these potential cumulative noise impacts will 
be short in duration.
    SPLs from impact pile driving and pier implosion have the potential 
to injure or kill fish in the immediate area. During previous pier 
implosion and pile driving activities, CALTRANS has reported mortality 
to marine mammals' prey species, including northern anchovies and 
Pacific herring (CALTRANS 2016). These few isolated fish mortality 
events are not anticipated to have a substantial effect on prey species 
population or their availability as a food resource for marine mammals.
    Studies also suggest that larger fish are generally less 
susceptible to death or injury than small fish. Moreover, elongated 
forms that are round in cross section are less at risk than deep-bodied 
forms. Orientation of fish relative to the shock wave may also affect 
the extent of injury. Open water pelagic fish (e.g., mackerel) seem to 
be less affected than

[[Page 67318]]

reef fishes. The results of most studies are dependent upon specific 
biological, environmental, explosive, and data recording factors.
    The huge variation in fish populations, including numbers, species, 
sizes, and orientation and range from the detonation point, makes it 
very difficult to accurately predict mortalities at any specific site 
of detonation. Most fish species experience a large number of natural 
mortalities, especially during early life-stages, and any small level 
of mortality caused by the CALTRANS' two controlled implosions will 
likely be insignificant to the population as a whole.

Mitigation Measures

    In order to issue an incidental take authorization 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.

1. Mitigation Measures for In-Water Pile Driving and Pile Removal

    For the CALTRANS SFOBB construction activities, NMFS requires the 
following mitigation measures to minimize the potential impacts to 
marine mammals in the project vicinity. The primary purpose of these 
mitigation measures is to detect marine mammals within or about to 
enter designated exclusion zones corresponding to NMFS current injury 
thresholds and to initiate immediate shutdown or power down of the 
piling hammer, making it very unlikely potential injury or TTS to 
marine mammals would occur, and to reduce the intensity of Level B 
behavioral harassment.
Use of Noise Attenuation Devices
    To reduce impact on marine mammals, CALTRANS shall use a 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 and H-piles.
Establishment of Exclusion and Level B Harassment Zones
    Before the commencement of in-water construction activities, which 
include impact pile driving and vibratory pile driving, CALTRANS shall 
establish ``exclusion zones'' where received underwater 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), respectively. Before the sizes of actual zones are determined 
based on hydroacoustic measurements, CALTRANS shall establish these 
zones based on prior measurements conducted during SFOBB constructions, 
as described in Table 2 of this document.

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

    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 (PSO) shall conduct 
initial survey of the exclusion zones 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 exclusion 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 small cetaceans 
(harbor porpoises and bottlenose dolphins), and 30 minutes for gray 
whales. If no marine mammals are seen by the observer in that time it 
can be assumed that the animal has moved beyond the exclusion zone.
    If pile driving of a segment ceases for 30 minutes or more and a 
marine mammal is sighted within the designated exclusion zone prior to 
commencement of pile driving, the observer(s) must notify the Resident 
Engineer (or other authorized individual) immediately and continue to 
monitor the exclusion zone. Operations may not resume until the marine 
mammal has exited the exclusion zone.
Soft Start
    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 higher noise exposure, 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.
Shut-Down Measure
    CALTRANS shall implement shutdown measures if a marine mammal is 
sighted approaching the Level A exclusion zone, or within 10 m of the 
pile driving and pile removal equipment, whichever is smaller. In-water 
construction activities shall be suspended until the marine mammal is 
sighted moving away from the exclusion zone, or if a pinniped, harbor 
porpoise, or bottlenose dolphin is not sighted for 15 minutes after the 
shutdown, or if a

[[Page 67319]]

gray whale is not sighted for 30 minutes after the shutdown.
    CALTRANS shall implement shutdown if a species for which 
authorization has not been granted (including but not limited to 
Guadalupe fur seals) or if a species for which authorization has been 
granted but the authorized takes are met, approaches or is observed 
within the Level B harassment zone.

2. Mitigation Measures for Confined Implosion

    For CALTRANS' Piers E4 and E5 controlled implosion, NMFS requires 
the following mitigation measures to minimize the potential impacts to 
marine mammals in the project vicinity. The primary purposes of these 
mitigation measures are to minimize sound levels from the activities, 
to monitor marine mammals within designated exclusion zones and zones 
of influence (ZOI). Specific mitigation measures are described below.
Time Restriction
    Implosion of Piers E4 and E5 would only be conducted during 
daylight hours and with enough time for pre and post implosion 
monitoring, and with good visibility when the largest exclusion zone 
can be visually monitored.
Installation of Blast Attenuation System
    Prior to the Piers E4 and E5 demolition, CALTRANS shall install a 
Blast Attenuation System (BAS) as described above to reduce the 
shockwave from the implosion.
Establishment of Level A Exclusion Zone
    Due to the different hearing sensitivities among different taxa of 
marine mammals, NMFS has established a series of take thresholds from 
underwater explosions for marine mammals belonging to different 
functional hearing groups (Table 3). Under these criteria, marine 
mammals from different taxa will have different impact zones (exclusion 
zones and zones of influence).
    CALTRANS will establish an exclusion zone for both the mortality 
and Level A harassment zone (permanent hearing threshold shift or PTS, 
GI track injury, and slight lung injury) using the largest radius 
estimated harbor and northern elephant seals. CALTRANS will use 
measured distances to marine mammal threshold distances from the 
implosion of Pier E3 as predicted distances to the thresholds for the 
implosions of Piers E4 and E5 (Table 4). The use of measured peak 
pressure, cumulative sound exposure level (SEL), and impulse levels 
from the Pier E3 implosion provide a conservative estimate for the 
implosions of Piers E4 and E5. The Piers E4 and E5 caisson structures 
are smaller than the Pier E3 caisson structure and will require fewer 
explosive charges to implode. The maximum charge weight for the 
implosions of Piers E4 and E5 is 35 pounds/delay, the same as used for 
the implosion of Pier E3. However, the total explosive weight, number 
of individual detonations, and total time of implosion event will be 
less for these smaller piers.

                                       Table 3--NMFS Take Thresholds for Marine Mammals From Underwater Implosions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Level B harassment               Level A               Serious injury
                                                ------------------------------------    harassment    ----------------------------------
            Group                   Species                                         ------------------     Gastro-                          Mortality
                                                    Behavioral            TTS                             intestinal          Lung
                                                                                            PTS             tract
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-freq cetacean............  Bottlenose        167 dB SEL......  172 dB SEL or     187 dB SEL or     237 dB SPL or    39.1M \1/3\      91.4M \1/3\
                                dolphin.                            224 dB SPLpk.     230 dB SPLpk.     104 psi.         (1+[D/10.081])   (1+[D/10.081])
                                                                                                                         \1/2\ Pa-sec.    \1/2\ Pa-sec
                                                                                                                        where: M = mass  where: M = mass
                                                                                                                         of the animals   of the animals
                                                                                                                         in kg.           in kg
                                                                                                                        D = depth of     D = depth of
                                                                                                                         animal in m.     animal in m.
High-freq cetacean...........  Harbor porpoise.  141 dB SEL......  146 dB SEL or     161 dB SEL or
                                                                    195 dB SPLpk.     201 dB SPLpk.
Phocidae.....................  Harbor seal &     172 dB SEL......  177 dB SEL or     192 dB SEL or
                                northern                            212 dB SPLpk.     218 dB SPLpk.
                                elephant seal.
Otariidae....................  California sea    195 dB SEL......  200 dB SEL or     215 dB SEL or
                                lion & northern                     212 dBpk.         218 dB SPLpk.
                                fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Note: All dB values are referenced to 1 [micro]Pa. SPLpk = Peak sound pressure level; psi = pounds per square inch.


      Table 4--Measured Distances to Underwater Blasting Threshold Criteria for Levels A and B Harassment and Mortality From the Pier E3 Implosion
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Level B criteria                                  Level A criteria
                                 ----------------------------------------------------------------------------------------------------
             Species                  Behavioral       TTS dual criteria   PTS dual criteria   Gastro-intestinal                           Mortality
                                       response                *                   *                 track            Lung injury
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor Seal.....................  2,460 ft (750 m)..  1,658 ft (505 m)..  507 ft (155 m)....  <100 ft (30 m)....  <100 ft (30 m)....  <100 ft (30 m).
                                                      104 ft (32 m).....  65 ft (20 m)......
California Sea Lion.............  387 ft (118 m)....  261 ft (80 m).....  80 ft (24 m)......  <100 ft (30 m)....  <100 ft (30 m)....  <100 ft (30 m).
                                                      104 ft (32 m).....  65 ft (20 m)......
Northern Elephant Seal..........  2,460 ft (750 m)..  1,658 ft (505 m)..  507 ft (155 m)....  <100 ft (30 m)....  <100 ft (30 m)....  <100 ft (30 m).
                                                      104 ft (32 m).....  65 ft (20 m)......
Northern fur seal...............  387 ft (118 m)....  261 ft (80 m).....  80 ft (24 m)......  <100 ft (30 m)....  <100 ft (30 m)....  <100 ft (30 m).
                                                      104 ft (32 m).....  65 ft (20 m)......

[[Page 67320]]

 
Harbor Porpoise.................  8,171 ft (2,491 m)  5,580 ft (1,701 m)  1,777 ft (542 m)..  <100 ft (30 m)....  <100 ft (30 m)....  <100 ft (30 m).
                                                      400 ft (122 m)....  249 ft (76 m).....
Bottlenose Dolphin..............  1,255 ft (383 m)..  855 ft (261 m)....  271 ft (83 m).....  <100 ft (30 m)....  <100 ft (30 m)....  <100 ft (30 m).
                                                      202 ft (62 m).....  112 ft (34 m).....
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: * For the TTS and PTS criteria thresholds with dual criteria, the largest criteria distances (i.e., more conservative) are shown in bold.

Establishment of Level B Temporary Hearing Threshold Shift (TTS) Zone 
of Influence
    As shown in Table 3, for harbor and northern elephant seals, this 
will cover the area out to 212 dB peak SPL or 177 dB SEL, whichever 
extends out the furthest. Hydroacoustic modeling indicates this 
isopleth would extend out to 1,658 ft (505 m) from the pier. For harbor 
porpoises, this will cover the area out to 195 dB peak SPL or 146 dB 
SEL, whichever extends out the furthest, to 5,580 ft (1,701 m) from the 
pier. As discussed previously, the presence of harbor porpoises in this 
area is unlikely but monitoring will be employed to confirm their 
absence. For California sea lions, the distance to the Level B TTS zone 
of influence will cover the area out to 212 dB peak SPL or 200 dB SEL. 
This distance was calculated at 261 ft (80 m) from Pier E3, well within 
the exclusion zone previously described. Hearing group specific Level B 
TTS zone of influence ranges are provided in Table 4.
Establishment of Level B Behavioral Zone of Influence
    As shown in Table 3, for harbor seals and northern elephant seals, 
this will cover the area out to 172 dB SEL. Hydroacoustic measurement 
indicates this isopleth would extend out to 2,460 ft (750 m) from the 
pier. For harbor porpoises, this will cover the area out to 141 dB SEL. 
Hydroacoustic measurement indicates this isopleth would extend out to 
8,171 ft (2,941 m) from the pier. As discussed previously, the presence 
of harbor porpoises in this area is unlikely but monitoring will be 
employed to confirm their absence. For California sea lions, the 
distance to the Level B behavioral harassment ZOI will cover the area 
out to 195 dB SEL. This distance was calculated at 387 ft (118 m) from 
the pier, well within the exclusion zone previously described. Hearing 
group specific Level B TTS zone of influence ranges are provided in 
Table 4.
Communication
    All PSOs will be equipped with mobile phones and a VHF radio as a 
backup. One person will be designated as the Lead PSO and will be in 
constant contact with the Resident Engineer on site and the blasting 
crew. The Lead PSO will coordinate marine mammal sightings with the 
other PSOs. PSOs will contact the other PSOs when a sighting is made 
within the exclusion zone or near the exclusion zone so that the PSOs 
within overlapping areas of responsibility can continue to track the 
animal and the Lead PSO is aware of the animal. If it is within 30 
minutes of blasting and an animal has entered the exclusion zone or is 
near it, the Lead PSO will notify the Resident Engineer and blasting 
crew. The Lead PSO will keep them informed of the disposition of the 
animal.
Mitigation Conclusions
    NMFS has carefully evaluated the mitigation measures and considered 
a range of other measures in the context of ensuring that NMFS 
prescribes the means of effecting the least practicable impact on the 
affected marine mammal species and stocks and their habitat. Our 
evaluation of potential measures included consideration of the 
following factors in relation to one another:
     The manner in which, and the degree to which, the 
successful implementation of the measure is expected to minimize 
adverse impacts to marine mammals.
     The proven or likely efficacy of the specific measure to 
minimize adverse impacts as planned.
     The practicability of the measure for applicant 
implementation.
    Any mitigation measure(s) prescribed by NMFS should be able to 
accomplish, have a reasonable likelihood of accomplishing (based on 
current science), or contribute to the accomplishment of one or more of 
the general goals listed below:
    (1) Avoidance or minimization of injury or death of marine mammals 
wherever possible (goals 2, 3, and 4 may contribute to this goal).
    (2) A reduction in the numbers of marine mammals (total number or 
number at biologically important time or location) exposed to received 
levels of pile driving and pile removal or other activities expected to 
result in the take of marine mammals (this goal may contribute to 1, 
above, or to reducing harassment takes only).
    (3) A reduction in the number of times (total number or number at 
biologically important time or location) individuals would be exposed 
to received levels of pile driving and pile removal, or other 
activities expected to result in the take of marine mammals (this goal 
may contribute to 1, above, or to reducing harassment takes only).
    (4) A reduction in the intensity of exposures (either total number 
or number at biologically important time or location) to received 
levels of pile driving, or other activities expected to result in the 
take of marine mammals (this goal may contribute to (1) above, or to 
reducing the severity of harassment takes only).
    (5) Avoidance or minimization of adverse effects to marine mammal 
habitat, paying special attention to the food base, activities that 
block or limit passage to or from biologically important areas, 
permanent destruction of habitat, or temporary destruction/disturbance 
of habitat during a biologically important time.
    (6) For monitoring directly related to mitigation--an increase in 
the probability of detecting marine mammals, thus allowing for more 
effective implementation of the mitigation.
    Based on our evaluation of the applicant's proposed mitigation 
measures, as well as other measures considered by NMFS, NMFS has 
determined that the mitigation measures provide the means of effecting 
the least practicable adverse impact on marine mammal species or stocks 
and their habitat, paying particular attention to rookeries, mating 
grounds, and areas of similar significance.

[[Page 67321]]

Monitoring and Reporting

    In order to issue an incidental take authorization (ITA) for an 
activity, section 101(a)(5)(D) of the MMPA states that NMFS must set 
forth, ``requirements pertaining to the monitoring and reporting of 
such taking.'' The MMPA implementing regulations at 50 CFR 
216.104(a)(13) indicate that requests for ITAs 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 in the proposed action area. CALTRANS has proposed marine 
mammal monitoring measures as part of the IHA application. It can be 
found at http://www.nmfs.noaa.gov/pr/permits/incidental.htm.
    Monitoring measures prescribed by NMFS should accomplish one or 
more of the following general goals:
    (1) An increase in the probability of detecting marine mammals, 
both within the mitigation zone (thus allowing for more effective 
implementation of the mitigation) and in general to generate more data 
to contribute to the analyses mentioned below;
    (2) An increase in our understanding of how many marine mammals are 
likely to be exposed to levels of pile driving that we associate with 
specific adverse effects, such as behavioral harassment, TTS, or PTS;
    (3) An increase in our understanding of how marine mammals respond 
to stimuli expected to result in take and how anticipated adverse 
effects on individuals (in different ways and to varying degrees) may 
impact the population, species, or stock (specifically through effects 
on annual rates of recruitment or survival) through any of the 
following methods:
    [ssquf] Behavioral observations in the presence of stimuli compared 
to observations in the absence of stimuli (need to be able to 
accurately predict received level, distance from source, and other 
pertinent information);
    [ssquf] Physiological measurements in the presence of stimuli 
compared to observations in the absence of stimuli (need to be able to 
accurately predict received level, distance from source, and other 
pertinent information);
    [ssquf] Distribution and/or abundance comparisons in times or areas 
with concentrated stimuli versus times or areas without stimuli;
    (4) An increased knowledge of the affected species; and
    (5) An increase in our understanding of the effectiveness of 
certain mitigation and monitoring measures.

Monitoring Measures

1. Monitoring for Pile Driving and Pile Removal

(1) Visual Monitoring
    NMFS made changes to the visual monitoring protocol during 
CALTRANS' pile driving and pile removal activities based, on a comment 
from the Marine Mammal Commission. Specifically, the revised visual 
monitoring protocol requires that PSOs conduct 100 percent visual 
monitoring of marine mammals during all pile driving and pile removal 
activities. In the proposed IHA, only 20 percent visual monitoring 
would have been required for Level B harassment zones during vibratory 
pile driving and pile removal activities. A complete description of the 
monitoring measure is provided below.
    Besides using monitoring for implementing mitigation (ensuring 
exclusion zones are clear of marine mammals before pile driving begins 
and after shutdown measures), marine mammal monitoring will also be 
conducted to assess potential impacts from CALTRANS construction 
activities. CALTRANS will implement onsite marine mammal monitoring for 
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 Level B 
harassment zone and attenuated impact pile driving (except pile 
proofing) for 180- and 190-dB re 1 [micro]Pa exclusion zones. CALTRANS 
will also monitor all attenuated impact pile driving for the 160-dB re 
1 [micro]Pa Level B harassment zone, and all vibratory pile driving for 
the 120-dB re 1 [micro]Pa Level B harassment zone.
(2) Protected Species Observers
    Monitoring of the pinniped and cetacean exclusion zones shall be 
conducted by a minimum of three qualified NMFS-approved 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.
(3) Data Collection
    Data on all observations will be recorded and will include the 
following information:
     Location of sighting;
     Species;
     Number of individuals;
     Number of calves present;
     Duration of sighting;
     Behavior of marine animals sighted;
     Direction of travel; and
     When in relation to construction activities did the 
sighting occur (e.g., before, ``soft-start'', during, or after the pile 
driving or removal).

2. Monitoring for Confined Implosion of Piers E4 and E5

    Monitoring for implosion impacts to marine mammals will be based on 
the SFOBB pile driving monitoring protocol. Pile driving has been 
conducted for the SFOBB construction project since 2000 with 
development of several NMFS-approved marine mammal monitoring plans 
(CALTRANS 2004; 2013). Most elements of these marine mammal monitoring 
plans are similar to what would be required for underwater implosions. 
These monitoring plans would include monitoring an exclusion zone and 
ZOIs for TTS and behavioral harassment described above.
(1) Protected Species Observers
    A minimum of 8-10 PSOs would be required during the Piers E4 and E5 
controlled implosion so that the exclusion zone, Level B Harassment TTS 
and Behavioral ZOIs, and surrounding area can be monitored. One PSO 
would be designated as the Lead PSO and would receive updates from 
other PSOs on the presence or absence of marine mammals within the 
exclusion zone and would notify the Environmental Compliance Manager of 
a cleared exclusion zone prior to the implosion.
(2) Monitoring Protocol
    Implosions of Piers E4 and E5 will be conducted only during 
daylight hours and with enough time for pre and post-implosion 
monitoring, and with good weather (i.e., clear skies and no high 
winds). This work will be conducted so that PSOs will be able to detect 
marine mammals within the exclusion zones and beyond. The Lead PSO will 
be in contact with other PSOs. If any marine mammals enter an exclusion 
zone within 30 minutes of blasting, the Lead PSO will notify the 
Environmental Compliance Manager that the implosion may need to be 
delayed. The Lead PSO will keep the Environmental Compliance Manager 
informed about the disposition of the animal. If the animal remains in 
the exclusion zone, blasting will be delayed until it has left the 
exclusion zone. If the animal dives and is not seen again, blasting 
will be delayed at least 15 minutes. After the implosion has occurred, 
the PSOs will continue to monitor the area for at least 60 minutes.

[[Page 67322]]

(3) Data Collection
    Each PSO will record the observation position, start and end times 
of observations, and weather conditions (i.e., sunny/cloudy, wind 
speed, fog, visibility). For each marine mammal sighting, the following 
will be recorded, if possible:
     Species.
     Number of animals (with or without pup/calf).
     Age class (pup/calf, juvenile, adult).
     Identifying marks or color (e.g., scars, red pelage, 
damaged dorsal fin).
     Position relative to Piers E4 or E5 (distance and 
direction).
     Movement (direction and relative speed).
     Behavior (e.g., logging [resting at the surface], 
swimming, spy-hopping [raising above the water surface to view the 
area], foraging).
(4) Post-Implosion Survey
    Although any injury or mortality from the implosions of Piers E4 
and E5 is very unlikely, boat or shore surveys will be conducted for 
three days following the event, to determine whether any injured or 
stranded marine mammals are in the area. If an injured or dead animal 
is discovered during these surveys or by other means, the NMFS-
designated stranding team will be contacted to pick up the animal. 
Veterinarians will treat the animal or will conduct a necropsy to 
attempt to determine whether it stranded because of the Piers E4 and E5 
implosions.
Reporting Measures
    CALTRANS would be required to submit a draft monitoring report 
within 90 days after completion of the construction work or the 
expiration of the IHA, whichever comes earlier. This draft report would 
detail the monitoring protocol, summarize the data recorded during 
monitoring, and estimate the number of marine mammals that may have 
been harassed. NMFS would have an opportunity to provide comments on 
the draft report within 30 days, and if NMFS has comments, CALTRANS 
would address the comments and submit a final report to NMFS within 30 
days. If no comments are provided by NMFS after 30 days receiving the 
report, the draft report is considered to be final.
Marine Mammal Stranding Plan
    A stranding plan for the Pier E3 implosion was prepared in 
cooperation with the local NMFS-designated marine mammal stranding, 
rescue, and rehabilitation center. An updated version of this plan will 
be implemented during implosions of Piers E4 and E5. Although avoidance 
and minimization measures likely will prevent any injuries, 
preparations will be made in the unlikely event that marine mammals are 
injured. Elements of the plan will include the following:
    1. The stranding crew will prepare treatment areas at an NMFS-
designated facility for cetaceans or pinnipeds that may be injured from 
the implosions. Preparation will include equipment to treat lung 
injuries, auditory testing equipment, dry and wet caged areas to hold 
animals, and operating rooms if surgical procedures are necessary.
    2. A stranding crew and a veterinarian will be on call near the 
Piers E4 and E5 area at the time of the implosions, to quickly recover 
any injured marine mammals, provide emergency veterinary care, 
stabilize the animal's condition, and transport individuals to an NMFS-
designated facility. If an injured or dead animal is found, NMFS (both 
the regional office and headquarters) will be notified immediately, 
even if the animal appears to be sick or injured from causes other than 
the implosions.
    3. Post-implosion surveys will be conducted immediately after the 
event and over the following three days to determine whether any 
injured or dead marine mammals are in the area.
    4. Any veterinarian procedures, euthanasia, rehabilitation 
decisions, and time of release or disposition of the animal will be at 
the discretion of the NMFS-designated facility staff and the 
veterinarians treating the animals. Any necropsies to determine whether 
the injuries or death of an animal was the result of an implosion or 
other anthropogenic or natural causes will be conducted at an NMFS-
designated facility by the stranding crew and veterinarians. The 
results will be communicated to both the CALTRANS and to NMFS as soon 
as possible, followed by a written report within a month.

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).
    The distance to marine mammal threshold criteria for pile driving 
and blasting activities, and corresponding ZOI have been determined 
based on underwater sound and pressure measurements collected during 
pervious activities in the SFOBB Project area. The numbers of marine 
mammals by species that may be taken by each type of take were 
calculated based on distance to the specific marine mammal harassment 
thresholds, number of days of the activity, and the estimated density 
of each species in the ZOI.

Estimates of Species Densities of Marine Mammals

    No systematic line transect surveys of marine mammals have been 
performed in the San Francisco Bay. Therefore, the in-water densities 
of harbor seals, California sea lions, and harbor porpoises were 
calculated based on 15 years of observations during monitoring for the 
SFOBB construction and demolition. The amount of monitoring performed 
per year varied depending on the frequency and duration of construction 
activities with the potential to affect marine mammals. During the 237 
days of monitoring from 2000 through 2015 (including 15 days of 
baseline monitoring in 2003), 822 harbor seals, 77 California sea 
lions, and nine harbor porpoises were observed within the waters of the 
SFOBB east span. Density estimates for other species were made from 
stranding data, provided by the Marine Mammal Center (MMC).
1. Pacific Harbor Seal Density Estimates
    Harbor seal density was calculated from all observations of animals 
in water during SFOBB Project monitoring from 2000 to 2015, divided by 
the size of the project area. These observations included data from 
baseline, pre-, during and post-pile driving, mechanical dismantling, 
onshore blasting, and offshore implosion activities. During this time, 
the population of harbor seals in the Bay remained stable (Manugian 
2013). Therefore, substantial differences in numbers or behaviors of 
seals hauling out, foraging, or in their movements are not anticipated. 
All harbor seal observations within a 1 km\2\ area were used in the 
estimate. Distances were recorded using a laser range finder (Bushnell 
Yardage Pro Elite 1500;  1.0 yard accuracy). Care was taken 
to eliminate multiple observations of the same animal, although this 
was difficult when more than three seals were foraging in the same 
area.
    Density of harbor seals was highest near YBI and Treasure Island, 
probably because of the haul-out site and nearby foraging areas in 
Coast Guard and

[[Page 67323]]

Clipper coves. Therefore, density estimates were calculated for a 
higher density area within 4,921 ft (1,500 m) west of Piers E4 and E5, 
which included the two foraging coves. A lower density estimate was 
calculated from the areas east of Piers E4 and E5, and beyond 4,921 ft 
(1,500 m) north and south of the bridge. Harbor seal densities in these 
two areas in spring-summer and fall-winter seasons are provided in 
Table 5.
2. California Sea Lion Density Estimates
    Within the SFOBB Project area, California sea lion density was 
calculated from all observations of animals in water during SFOBB 
Project monitoring from 2000 to 2015, divided by the size of the 
project area. These observations included data from baseline, pre, 
during, and post-pile driving, mechanical dismantling, onshore 
blasting, and offshore implosion activities. All sea lion observations 
within a 1 km\2\ area were used in the estimate. Distances were 
recorded using a laser range finder (Bushnell Yardage Pro Elite 1500; 
 1.0 yard accuracy). Care was taken to eliminate multiple 
observations of the same animal, although most sea lion observations 
involve a single animal.
    California sea lion densities in late spring-early summer and late 
summer-fall seasons are provided in Table 5.
3. Northern Elephant Seal Density Estimates
    Northern elephant seal density in the project area was calculated 
from the stranding records of the MMC, from 2004 to 2014. These data 
included both injured or sick seals and healthy seals. Approximately 
100 elephant seals were reported in the Bay during this time; most of 
these hauled out and likely were sick or starving. The actual number of 
individuals in the Bay may have been higher because not all individuals 
would necessarily have hauled out. Some individuals may have simply 
left the Bay soon after entering. Data from the MMC show several 
elephant seals stranding on Treasure Island, and one healthy elephant 
seal was observed resting on the beach in Clipper Cove in 2012. 
Elephant seal pups or juveniles also may have stranded after weaning in 
the spring and when they returned to California in the fall (September 
through November). Density of northern elephant seal is estimated as 
the number of stranded seals over the SFOBB project area, which is 0.03 
animal/km\2\ (Table 5).
4. Harbor Porpoise Density Estimates
    Harbor porpoise density was calculated from all observations during 
SFOBB Project monitoring, from 2000 to 2015. These observations 
included data from baseline, pre, during and post-pile driving, and 
onshore implosion activities. Over this period, the number of harbor 
porpoises that were observed entering and using the Bay increased. 
During the 15 years of monitoring in the SFOBB Project area, only nine 
harbor porpoises were observed, and all occurred between 2006 and 2015 
(including two in 2014 and five in 2015). Density of harbor porpoise is 
estimated to be 0.021 animal/km\2\ (Table 5).
5. Gray Whale Density Estimate
    Gray whale density was estimated for the entire Bay as no 
observations have occurred of gray whales in the SFOBB Project area. 
Each year, two to six gray whales enter the Bay, presumably to feed, in 
the late winter through spring (February through April), per the MMC. 
Gray whales rarely occur in the Bay from October through December. The 
gray whale density was estimated based on a maximum of 6 whales 
occurring within the main area of San Francisco Bay, which yielded a 
density of 0.00004/km\2\ (Thorson, pers. comm., 2014).

                 Table 5--Estimated In-Water Density of Marine Mammals in the SFOBB Project Area
----------------------------------------------------------------------------------------------------------------
                                                                                                   Density east
                                                                                   Density west     of piers E4
                                                                                    of piers E4    and E5 and/or
                    Species                         Main season of occurrence      and E5 within  beyond 1,500 m
                                                                                    1,500 m of       of SFOBB
                                                                                  SFOBB (animals/    (animals/
                                                                                      km\2\)          km\2\)
----------------------------------------------------------------------------------------------------------------
Harbor Seal...................................  Spring-Summer...................            0.32            0.17
Harbor Seal...................................  Fall-Winter.....................            0.83            0.17
California Sea Lion...........................  Late Summer-Fall (post breeding             0.09            0.09
                                                 season).
California Sea Lion...........................  Late Spring-Early Summer                    0.04            0.04
                                                 (breeding season).
Northern Elephant Seal........................  Late Spring-Early Winter........            0.03            0.03
Harbor Porpoise...............................  All Year........................           0.021           0.021
Gray Whale....................................  Late Winter and Spring..........         0.00004         0.00004
----------------------------------------------------------------------------------------------------------------
Note: Densities for Pacific harbor seals, California sea lions and harbor porpoises are based on monitoring for
  the east span of the SFOBB from 2000 to 2013. Gray whale and elephant seal densities are estimated from
  sighting and stranding data from the MMC.

Estimated Takes by Pile Driving and Pile Removal

    The numbers of marine mammals by species that may be taken by pile 
driving were calculated by multiplying the ensonified area above a 
specific species exposure threshold by the days of the activity and by 
the estimated density of each species in the ensonified area. As 
discussed above, threshold distances were determined based on 
previously measured distances to thresholds during the driving of 42-
inch-diameter (1.07 meters) pipe piles. The same threshold distances 
have been applied to all types and sizes of piles proposed for 
installation and removal (i.e., H-piles, and pipe piles equal to or 
less than 36 inches (0.91 meter)). The take estimate is based on 132 
days of pile driving to install 200 piles.
    For rare species of which the density estimates are unknown, such 
as northern fur seal and bottlenose dolphin, NMFS worked with CALTRANS 
and allotted 20 northern fur seals and 10 bottlenose dolphin for 
incidental take by Level B behavioral harassment to cover the chance 
encounter in case these animals happen to occur in the project area.
    A summary of estimated takes by in-water pile driving and pile 
removal is provided in Table 6.

[[Page 67324]]



  Table 6--Estimated Take of Marine Mammals From Pile Driving and Pile
                           Removal Activities
------------------------------------------------------------------------
                                              Level B
                                            harassment        Level A
                 Species                    (behavioral     harassment
                                             response)
------------------------------------------------------------------------
Pacific Harbor Seal.....................             862               0
California Sea Lion.....................             108               0
Northern Elephant Seal..................              13               0
Harbor Porpoise.........................              13               0
Gray Whale..............................               1               0
Northern fur seal.......................              20               0
Bottlenose dolphin......................              10               0
------------------------------------------------------------------------

    The number of marine mammals by species that may be taken by 
implosion of Piers E4 and E5 were calculated based on distances to the 
marine mammal threshold for explosions (Table 4) and the estimated 
density of each species in the ensonified areas (Table 5). A summary of 
estimated and requested takes by controlled implosion is provided in 
Table 8.

                    Table 7--Estimated Exposures of Marine Mammals to the Pier E4 and E5 Implosions for Levels A and B, and Mortality
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Level B exposures                       Level A exposures
                                                         --------------------------------------------------------------------------------
                         Species                                                                              Gastro-                        Mortality
                                                            Behavioral          TTS             PTS         intestinal      Slight lung
                                                             response                                      track injury       injury
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pacific Harbor Seal.....................................               1               1               0               0               0               0
California Sea Lion.....................................               0               0               0               0               0               0
Northern Elephant Seal..................................               0               0               0               0               0               0
Harbor Porpoise.........................................               0               0               0               0               0               0
--------------------------------------------------------------------------------------------------------------------------------------------------------

    However, the number of marine mammals in the area at any given time 
is highly variable. Animal movement depends on time of day, tide 
levels, weather, and availability and distribution of prey species. 
Therefore, to account for potential high animal density that could 
occur during the short window of controlled implosion, NMFS worked with 
CALTRANS and adjusted the estimated number upwards for the requested 
takes. These adjustments were based on likely group sizes of these 
animals.
    A summary of estimated takes by implosion of Piers E4 and E5 is 
provided in Table 8.

  Table 8--Summary of Requested Takes of Marine Mammals for the Pier E4
                            and E5 Implosions
------------------------------------------------------------------------
                                              Level B
                 Species                    behavioral      Level B TTS
------------------------------------------------------------------------
Pacific harbor seal.....................              12               6
California sea lion.....................               3               2
Northern elephant seal..................               2               1
Harbor porpoise.........................               6               3
Northern fur seal.......................               1               1
Bottlenose dolphin......................               2               2
------------------------------------------------------------------------

    A summary of the request incidental takes of marine mammals for 
CALTRANS SFOBB construction activity, including from in-water pile 
driving/pile removal and controlled implosion for Piers E4 and E5 is 
provided in Table 9. These take estimates represent ``instances'' of 
take and are likely overestimates of the number of individual animals 
taken, since some individuals are likely taken on multiple days. The 
more likely the individuals are to remain in the action area for 
multiple days, the greater the overestimate of individuals.

                Table 9--Summary of Authorized Takes of Marine Mammals for CALTRANS SFOBB Project
----------------------------------------------------------------------------------------------------------------
                                                      Level B                                         % take
                     Species                        behavioral      Level B TTS     Population      population
----------------------------------------------------------------------------------------------------------------
Pacific harbor seal.............................             874               6          30,968            2.84
California sea lion.............................             111               2         296,750            0.04
Northern elephant seal..........................              15               1         179,000            0.01
Harbor porpoise.................................              19               3           9,886            0.22
Northern fur seal...............................              21               1          12,844            0.17

[[Page 67325]]

 
Gray whale......................................               1               0          20,990            0.00
Bottlenose dolphin..............................              12               2             323            4.33
----------------------------------------------------------------------------------------------------------------

Technical Guidance for Assessing the Effects of Anthropogenic Sound on 
Marine Mammal Hearing

    On August 4, 2016, NMFS released its Technical Guidance for 
Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing 
(Guidance). This new guidance established new thresholds for predicting 
auditory injury, which equates to Level A harassment under the MMPA. In 
the Federal Register notice (81 FR 51694), NMFS explained the approach 
it would take during a transition period, wherein we balance the need 
to consider this new best available science with the fact that some 
applicants have already committed time and resources to the development 
of analyses based on our previous guidance and have constraints that 
preclude the recalculation of take estimates, as well as where the 
action is in the agency's decision-making pipeline. In that Notice, we 
included a non-exhaustive list of factors that would inform the most 
appropriate approach for considering the new Guidance, including: The 
scope of effects; how far in the process the applicant has progressed; 
when the authorization is needed; the cost and complexity of the 
analysis; and the degree to which the guidance is expected to affect 
our analysis. In this case, CALTRANS submitted an adequate and complete 
application in a timely manner and indicated that they would need to 
receive an IHA (if issued) by early September 2016. The CALTRANS 
analysis put forth in the proposed IHA contemplated the potential for 
small numbers of permanent or temporary threshold shift, but ultimately 
concluded that permanent threshold shift will not occur. Consideration 
of the new Guidance suggested that in the absence of mitigation a small 
number of Level A takes could potentially occur to one harbor seal. 
However, CALTRANS has a robust and practicable monitoring and 
mitigation program--and in addition they enlarged the exclusion zone 
for pile driving from 95 m to 156 m for 14'' H-pile and to 183 m for 
36'' steel pipe when driven by an impact hammer, providing further 
protection. When this mitigation is considered in combination with the 
fact that a fair number of marine mammals are expected to intentionally 
avoid approaching within distances of this slow-moving source that 
would result in injury, we believe that injury is unlikely. In summary, 
we have considered the new Guidance and believe that the likelihood of 
injury is adequately addressed in the analysis and appropriate 
protective measures are in place in the IHA.

Analysis and Determinations

Negligible Impact

    Negligible impact is ``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'' (50 CFR 216.103). 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 must consider 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 harassment takes, 
the number of estimated mortalities, and effects on habitat.
    To avoid repetition, this introductory discussion of our analyses 
applies to all the species listed in Table 9, given that the 
anticipated effects of CALTRANS' SFOBB construction activities 
involving pile driving and pile removal and controlled implosions for 
Piers E4 and E5 on marine mammals are expected to be relatively similar 
in nature. There is no information about the nature or severity of the 
impacts, or the size, status, or structure of any species or stock that 
would lead to a different analysis for this activity, or else species-
specific factors would be identified and analyzed.
    No injuries or mortalities are anticipated to occur as a result of 
CALTRANS' SFOBB construction activity associated with pile driving and 
pile removal and controlled implosion to demolish Piers E4 and E5, and 
none are authorized. The relatively low marine mammal density, 
relatively small Level A harassment zones, and robust mitigation plan 
make injury takes of marine mammals unlikely, based on take calculation 
described above. In addition, the Level A exclusion zones would be 
thoroughly monitored before the implosion, and detonation activity 
would be postponed if an marine mammal is sighted within the exclusion 
zone.
    The takes that are anticipated and authorized are expected to be 
limited to short-term Level B harassment (behavioral and TTS). Marine 
mammals (Pacific harbor seal, northern elephant seal, California sea 
lion, northern fur seal, gray whale, harbor porpoise, and bottlenose 
dolphin) present in the vicinity of the action area and taken by Level 
B harassment would most likely show overt brief disturbance (startle 
reaction) and avoidance of the area from elevated noise level during 
pile driving and pile removal and the implosion noise. A few marine 
mammals could experience TTS if they occur within the Level B TTS ZOI 
during the two implosion events. However, as discussed early in this 
document, TTS is a temporary loss of hearing sensitivity when exposed 
to loud sound, and the hearing threshold is expected to recover 
completely within minutes to hours. Therefore, it is not considered an 
injury. In addition, even if an animal receives a TTS, the TTS would be 
a one-time event from a brief impulse noise (about 5 seconds), making 
it unlikely that the TTS would involve into PTS. Finally, there is no 
critical habitat or other biologically important areas in the vicinity 
of CALTRANS' Pier E4 and E5 controlled implosion areas (Calambokidis et 
al., 2015).
    The project also is not expected to have significant adverse 
effects on affected marine mammals' habitat, as analyzed in detail in 
the ``Anticipated Effects on Marine Mammal Habitat'' section. There is 
no biologically important area in the vicinity of the SFOBB project 
area. The project activities would not permanently modify existing 
marine mammal habitat. The activities may kill some fish and

[[Page 67326]]

cause other fish to leave the area temporarily, thus impacting marine 
mammals' foraging opportunities in a limited portion of the foraging 
range; but, because of the short duration of the activities and the 
relatively small area of the habitat that may be affected, the impacts 
to marine mammal habitat are not expected to cause significant or long-
term negative consequences.
    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 monitoring and mitigation 
measures, NMFS finds that the total marine mammal take from CALTRANS's 
SFOBB construction activity and the associated Piers E4 and E5 
demolition via controlled implosion will have a negligible impact on 
the affected marine mammal species or stocks.

Small Numbers

    The requested takes represent less than 4.33 percent of all 
populations or stocks potentially impacted (see Table 9 in this 
document). These take estimates represent the percentage of each 
species or stock that could be taken by Level B behavioral harassment 
and TTS (Level B harassment). The numbers of marine mammals estimated 
to be taken are small proportions of the total populations of the 
affected species or stocks. In addition, the mitigation and monitoring 
measures (described previously in this document) prescribed in the IHA 
are expected to reduce even further any potential disturbance to 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 finds that small numbers of marine mammals will be taken 
relative to the populations of the affected species or stocks.

Impact on Availability of Affected Species for Taking for Subsistence 
Uses

    There are no subsistence uses of marine mammals in the project 
area; and, thus, no subsistence uses impacted by this action. 
Therefore, NMFS has determined that the total taking of affected 
species or stocks would not have an unmitigable adverse impact on the 
availability of such species or stocks for taking for subsistence 
purposes.

Endangered Species Act

    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.

National Environmental Policy Act

    NMFS prepared an Environmental Assessment (EA) for the take of 
marine mammals incidental to construction of the East Span of the SFOBB 
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 
FONSI was signed on August 5, 2009. In addition, for CALTRANS' Piers E4 
and E5 demolition using controlled implosion, NMFS prepared an SEA and 
analyzed the potential impacts to marine mammals that would result from 
the modification. A FONSI was signed on September 3, 2015. The activity 
and expected impacts remain within what was previously analyzed in the 
EA and SEAs. Therefore, no additional NEPA analysis is warranted. A 
copy of the SEA and FONSI is available upon request (see ADDRESSES).

Authorization

    As a result of these determinations, NMFS has issued an IHA to 
CALTRANS for the take of marine mammals, by Level B harassment, 
incidental to conducting SFOBB project in the San Francisco Bay, which 
also includes the mitigation, monitoring, and reporting requirements 
described in this Notice.

    Dated: September 26, 2016.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2016-23602 Filed 9-29-16; 8:45 am]
BILLING CODE 3510-22-P