Taking of Marine Mammals Incidental to Specified Activities; Construction of the East Span of the San Francisco-Oakland Bay Bridge, 43710-43719 [2015-18021]

Agencies

• DEPARTMENT OF COMMERCE
• National Oceanic and Atmospheric Administration

[Federal Register Volume 80, Number 141 (Thursday, July 23, 2015)]
[Notices]
[Pages 43710-43719]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-18021]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XD829


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, four species of marine mammals 
during activities related to the construction of Pier 3 of the East 
Span of the San Francisco-Oakland Bay Bridge (SF-OBB) in California

DATES: This authorization is effective from July 15, 2015 through July 
14, 2016.

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

SUPPLEMENTARY INFORMATION:

Availability

    An electronic copy of CALTRANS' application and supporting 
documents, as well as a list of the references cited in this document, 
may be obtained by visiting the Internet at: www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing 
these documents, please call the contact listed above (see FOR FURTHER 
INFORMATION CONTACT).

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.
    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 an authorization to 
incidentally take small numbers of marine mammals by harassment. 
Section 101(a)(5)(D) establishes a 45-day time limit for NMFS' review 
of an application followed by a 30-day public notice and comment period 
on any proposed authorizations for the incidental harassment of marine 
mammals. Within 45 days of the close of the comment period, NMFS must 
either issue or deny the authorization. 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

[[Page 43711]]

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

Summary of Request

    On December 15, 2014, CALTRANS submitted its most recent request to 
NOAA requesting an IHA for the possible harassment of small numbers of 
California sea lions (Zalophus californianus), Pacific harbor seals 
(Phoca vitulina richardsii), harbor porpoises (Phocoena phocoena), and 
gray whales (Eschrichtius robustus) incidental to construction 
associated with a replacement bridge for the East Span of the SF-OBB, 
in San Francisco Bay (SFB, or Bay), California.
    An IHA was previously issued to CALTRANS for this activity on 
January 8, 2014 (79 FR 2421; January 14, 2014), based on activities 
described on CALTRANS' IHA application dated April 13, 2013. That IHA 
expired on January 7, 2015. Since the construction activity would 
continue for another two years, CALTRANS requests to renew its IHA. In 
its IHA renewal request, CALTRANS also states that there has been no 
change in the scope of work for the SF-OBB Project from what was 
outlined in its April 13, 2013, IHA application project description, 
the Federal Register notice for the proposed IHA (78 FR 60852; October 
2, 2013), and the Federal Register notice for the issuance of that IHA 
(79 FR 2421; January 14, 2014). On November 10, 2003, NMFS issued the 
first project-related IHA authorizing the take of small numbers of 
marine mammals incidental to the construction of the SFOBB Project. 
CALTRANS has been issued a total of seven subsequent IHAs for the SF-
OBB Project to date, excluding the application currently under review.

Description of the Specified Activity

Overview

    Construction activities for the replacement of the SF-OBB 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.
    This stage of the project covered under the IHA will include the 
mechanical dismantling of marine foundations of the East Span of the 
bridge as well as the installation of approximately 200 steel piles.

Dates and Duration

    In-water activities are expected to begin in July 2015. Up to 128 
days of pile driving may occur under the IHA. However, the schedule for 
this project is highly variable. As such, activities covered under this 
IHA may occur anytime between July 15, 2015 and July 14, 2016 which are 
the effective dates of the IHA.

Specific Geographic Region

    The project site is located in San Francisco Bay around the east 
span of the SFOBB.

Detailed Description of Activities

    We provided a description of the proposed action in our Federal 
Register notice announcing the proposed authorization (80 FR 23774; 
April 29, 2015). Please refer to that document; we provide only summary 
information here.
    The proposed action would involve the mechanical dismantling of 
marine foundations and superstructure components of the East Span of 
the bridge as well as the installation of approximately 200 steel 
piles. These piles include 0.45-meter, 0.61-meter, 0.91-meter (18-inch, 
24-inch, and 36-inch) diameter pipe piles, and 0.34 meter (14-inch) H-
piles on up to 128 days. These piles will be installed in the water to 
construct temporary supports between Piers E4-E8, which will help with 
the dismantling process by providing support to the original bridge 
superstructure as it is taken down. Both vibratory and impact hammers 
could be used to install pipe piles depending on the substrate. In 
addition, CALTRANS would remove various bridge superstructures 
including trusses, road decks, and steel and concrete support towers. 
The concrete foundation of the bridge would be removed using various 
mechanical means including saw cutting, flame cutting, mechanical 
splitting, drilling, pulverizing, and/or hydrocutting. Some of the 
installed piles may be removed under this IHA, but the contractor has 
until 2018 to remove all 200 piles.

Comments and Responses

    A notice of NMFS' proposal to issue an IHA was published in the 
Federal Register on April 29, 2015 (80 FR 23774). During the 30-day 
public comment period, the Marine Mammal Commission submitted a letter. 
The letter is available on the Internet www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. All comments specific to CALTRANS' 
application that address the statutory and regulatory requirements or 
findings NMFS must make to issue an IHA are addressed in this section 
of the Federal Register notice.
    Comment 1: The Commission noted that during the last authorization 
marine mammal monitoring did not occur 100 percent of time spent on 
activities authorized under the IHA. The Commission believes that this 
results in underestimates the number of takes of marine mammals known 
to occur in the project area. Monitoring during all in-water sound-
producing activities is the only way for CALTRANS and NMFS to be 
confident that the numbers of marine mammals taken are within the 
limits authorized and the least practicable impact occurs. For these 
reasons, the Commission recommended that NMFS require CALTRANS to 
implement full-time monitoring of Level A and B harassment zones during 
all in- water sound-producing activities (i.e., pile driving and 
dismantling activities).
    Response 1: NMFS does not agree with the Commission's 
recommendation. NMFS had discussed with CALTRANS specific protocols 
concerning marine mammal monitoring during its proposed in-water 
construction activities. As described in detail in the Federal Register 
notice for the previous proposed IHA (79 FR 2421; January 14, 2014) and 
in CALTRANS' IHA application, CALTRANS' planned construction includes 
installation of up to 635 temporary falsework piles, 1,925 steel sheet 
piles, and various mechanical dismantling activities over several 
years. The extent of the work made it infeasible and costly to 
implement marine mammal monitoring for Level A and B harassment zones 
at all times, particularly since some of the Level B harassment zones 
for vibratory pile driving extend to a radius of 2 km. CALTRANS will 
monitor the 180 and 190 dB exclusion zones and 160 dB behavioral 
harassment zone for all unattenuated impact pile driving of H-piles, 
and the 180 and 190 dB exclusion zones for attenuated impact pile 
driving and mechanical dismantling, thereby minimizing the possibility 
of injury. Further, for the purposes of better understand behavioral 
efforts, CALTRANS will also monitor the 160 dB behavioral harassment 
zone for 20% of the attenuated impact pile driving, and 120 dB 
behavioral harassment zone for 20% of vibratory pile driving and 
mechanic dismantling. Results have been extrapolated in past monitoring 
reports and will continue to be extrapolated in the future reports. 
Results of past monitoring reports are

[[Page 43712]]

discussed later in this notice in the section in Monitoring and 
reporting. CALTRANS, however, will not monitor the unattenuated impact 
pile proofing, which only lasts for less than one minute. Proposed 
proofing of piles will be limited to a maximum of two piles per day, 
and for less than 1 minute per pile, administering a maximum of twenty 
blows per pile. CALTRANS states, and NMFS agrees, that the logistics of 
scheduling and mobilizing a monitoring team for activities that will 
last less than one minute is not practical.
    Comment 2: The Commission noted that each authorization under 
section 101(a)(5)(D) is a separate undertaking and should contain 
sufficient information to allow for meaningful public review and 
comment. The Commission recommended in 2013 that NMFS include in each 
proposed incidental harassment authorization it publishes in the 
Federal Register a detailed description of the proposed activities 
rather than referring to previous documents. NMFS agreed and stated 
that it would provide such detailed descriptions in the Federal 
Register notices moving forward (see 79 FR 2422). However, NMFS' 
current notice did not include such a description. The Commission again 
recommends that NMFS include in each proposed incidental harassment 
authorization published in the Federal Register a detailed description 
of the proposed activities rather than referring to previous documents.
    Response 2: The CALTRANS bridge project is a multi-year, multi-
stage construction initiative. The schedule and scope of this project 
have undergone multiple revisions. NMFS felt that it captured the 
essential elements of what is proposed to occur under the proposed 
authorization under review. NMFS has added additional information to 
the Detailed Description of Activity section of this Federal Register 
Notice. NMFS will include a comprehensive description of proposed 
activities in future proposed notices.

Description of Marine Mammals in the Area of the Specified Activity

    There are four marine mammal species known to occur in the vicinity 
of the SF-OBB in California which may be subjected to Level B 
harassment. These are the Pacific harbor seal, California sea lion, 
gray whale, and harbor porpoise.
    We have reviewed CALTRANS' detailed species descriptions, including 
life history information, for accuracy and completeness and refer the 
reader to Section 3 of CALTRANS' application as well as the proposed 
incidental harassment authorization published in the Federal Register 
(80 FR 23774) instead of reprinting the information here. Please also 
refer to NMFS' Web site (www.nmfs.noaa.gov/pr/species/mammals) for 
generalized species accounts which provide information regarding the 
biology and behavior of the marine resources that occur in SE Alaska. 
We provided additional information for the potentially affected stocks, 
including details of stock-wide status, trends, and threats, in our 
Federal Register notice of proposed authorization (80 FR 23774).
    Table 1 lists marine mammal stocks that could occur in the vicinity 
of the SFOBB project that may be subject to Level B harassment and 
summarizes key information regarding stock status and abundance. 
Taxonomically, we follow Committee on Taxonomy (2014). Please see NMFS' 
Stock Assessment Reports (SAR), available at www.nmfs.noaa.gov/pr/sars, 
for more detailed accounts of these stocks' status and abundance.

Table 1--List of Marine Mammal Species Under NMFS Jurisdiction That Occur in the Vicinity of SF-OBB Project Area
                                                        *
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                                                                                      Stock         Population
         Common name               Stock       Scientific name     ESA Status       abundance         trend
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Harbor Seal.................  California.....  Phoca vitulina.  Not listed.....          30,196  Decreasing.
California sea lion.........  United States..  Zalophus         Not listed.....         296,750  Increasing.
                                                californianus.
Gray whale..................  Eastern North    Eschrichtius     Not listed.....          19,126  Increasing.
                               Pacific Stock.   robustus.
Harbor porpoise.............  San Francisco-   Phocoena         Not listed.....           9,886  Stable.
                               Russian River.   phocoena.
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* Estimated abundance numbers come primarily from NMFS 2014 Pacific Marine Mammal Stock Assessment Report
  (Carretta et al. 2014).

Potential Effects of the Specified Activity on Marine Mammals

    The Federal Register notice of proposed authorization (80 FR 
23744), incorporated here by reference, provides a general background 
on sound relevant to the specified activity as well as a detailed 
description of marine mammal hearing and of the potential effects of 
these construction activities on marine mammals.

Anticipated Effects on Habitat

    We described potential impacts to marine mammal habitat in detail 
in our Federal Register notice of proposed authorization. In summary, 
the project activities would not modify existing marine mammal habitat. 
The activities may cause some fish to leave the area of disturbance, 
thus temporarily 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 for 
individual marine mammals or their populations

Mitigation

    In order to issue an IHA under section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, ``and other means of effecting the least practicable 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.
    Measurements from similar pile driving events were coupled with 
practical spreading loss to estimate zones of influence (ZOI; see 
``Estimated Take by Incidental Harassment''). ZOIs are often used to 
establish a mitigation zone around each pile (when deemed practicable) 
to prevent Level A harassment to marine mammals, and also provide 
estimates of the areas within which Level B harassment might occur. 
ZOIs may vary between different diameter piles and types of 
installation methods. CALTRANS will employ the following mitigation 
measures:
    (a) Conduct briefings between construction supervisors and crews, 
marine mammal monitoring team, and CALTRANS staff prior to the start of 
all

[[Page 43713]]

pile driving activity, and when new personnel join the work, in order 
to explain responsibilities, communication procedures, marine mammal 
monitoring protocol, and operational procedures.
    (b) For in-water heavy machinery work other than pile driving 
(using, e.g., standard barges, tug boats, barge-mounted excavators, or 
clamshell equipment used to place or remove material), if a marine 
mammal comes within 10 m, operations shall cease and vessels shall 
reduce speed to the minimum level required to maintain steerage and 
safe working conditions. This type of work could include the following 
activities: (1) Movement of the barge to the pile location or (2) 
positioning of the pile on the substrate via a crane (i.e., stabbing 
the pile).

Monitoring and Shutdown for Pile Driving

    The following measures apply to CALTRANS' mitigation through 
shutdown and disturbance zones:
    Shutdown Zone--For all pile driving activities, CALTRANS will 
establish shutdown zones in which SPLs equal or exceed the 180/190 dB 
rms acoustic injury criteria to define the areas where shutdown of 
activity will occur upon sighting of a marine mammal (or in 
anticipation of an animal entering the defined area), thus preventing 
injury of marine mammals. For impact driving this is 235 meters. For 
vibratory driving, CALTRANS's activities are not expected to produce 
sound at or above the 180 dB rms injury criterion. Before the sizes of 
actual zones are determined based on hydroacoustic measurements, 
CALTRANS shall establish this zone based on prior measurements 
conducted during SF-OBB constructions, as described in Table 1 of this 
document. CALTRANS will also implement a minimum shutdown zone of 10 m 
radius for all marine mammals around all vibratory pile driving and 
removal activity and 100 m radius around any dismantling activity. 
These precautionary measures are intended to further reduce the 
unlikely possibility of injury from direct physical interaction with 
construction operations.
    Disturbance Zone--Disturbance zones are the areas in which SPLs 
equal or exceed 120 dB rms (for continuous sound) for pile driving 
installation and removal. This is 2,000 meters for vibratory driving 
and 1,000 meters for impact driving. Disturbance zones provide utility 
for monitoring conducted for mitigation purposes (i.e., shutdown zone 
monitoring) by establishing monitoring protocols for areas adjacent to 
the shutdown zones. Monitoring of disturbance zones enables observers 
to be aware of and communicate the presence of marine mammals in the 
project area but outside the shutdown zone and thus prepare for 
potential shutdowns of activity. However, the primary purpose of 
disturbance zone monitoring is for documenting incidents of Level B 
harassment; disturbance zone monitoring is discussed in greater detail 
later (see ``Monitoring and Reporting''). Nominal radial distances for 
disturbance zones are shown in Table 1.

  Table 1--Temporary exclusion and Level B Harassment Zones for Various Pile Driving and Dismantling Activities
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                                                    Distance to     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)
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Vibratory Driving.............  24..............           2,000              NA              NA              NA
                                36..............           2,000              NA              NA              NA
                                Sheet pile......           2,000              NA              NA              NA
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
Dismantling...................  ................           2,000              NA             100             100
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    Once hydroacoustic measurements of pile driving and mechanical 
dismantling activities have been conducted, CALTRANS shall revise the 
sizes of the zones based on actual measurements.
    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 or impact driving of H-
piles.
    In order to document observed incidents of harassment, observers 
record all marine mammal observations, regardless of location. The 
observer's location, as well as the location of the pile being driven, 
is known from a GPS. The location of the animal is estimated as a 
distance from the observer, which is then compared to the location from 
the pile and the estimated ZOIs for relevant activities (i.e., pile 
installation and removal). This information may then be used to 
extrapolate observed takes to reach an approximate understanding of 
actual total takes.
    Time Restrictions--Work will occur only during daylight hours, when 
visual monitoring of marine mammals can be conducted. In addition, all 
in-water construction will be limited to the period between July 15, 
2015 and July 14, 2016.
    Soft Start--The use of a soft start procedure is believed to 
provide additional protection to marine mammals by warning or providing 
a chance to leave the area prior to the hammer operating at full 
capacity, and typically involves a requirement to initiate sound from 
the hammer at reduced energy followed by a waiting period. This 
procedure is repeated two additional times. It is difficult to specify 
the reduction in energy for any given hammer because of variation 
across drivers and, for impact hammers, the actual number of strikes at 
reduced energy will vary because operating the hammer at less than full 
power results in ``bouncing'' of the hammer as it strikes the pile, 
resulting in multiple ``strikes.'' The project will utilize soft start 
techniques for both impact and vibratory pile driving. We require 
CALTRANS to initiate sound from vibratory hammers for fifteen seconds 
at reduced energy followed by a thirty-second waiting period, with the 
procedure repeated two additional times. For impact driving, we require 
an

[[Page 43714]]

initial set of three strikes from the impact hammer at reduced energy, 
followed by a thirty-second waiting period, then two subsequent three 
strike sets. Soft start will be required at the beginning of each day's 
pile driving work and at any time following a cessation of pile driving 
of 20 minutes or longer (specific to either vibratory or impact 
driving).
    Power Down and Shut-down--Although power down and shut-down 
measures will not be required for impact pile driving and removal 
activities due to the nature of sediments in the Bay, these measures 
will be required for mechanical dismantling activities. The contractor 
performing mechanical dismantling work will stop in-water noise 
generation.

Monitoring

    Monitoring Protocols--Monitoring would be conducted before, during, 
and after pile driving, pile and mechanical dismantling. In addition, 
observers shall record all incidents of marine mammal occurrence, 
regardless of distance from activity, and shall document any behavioral 
reactions in concert with distance from piles being driven. 
Observations made outside the shutdown zone will not result in shutdown 
and that pile segment would be completed without cessation, unless the 
animal approaches or enters the shutdown zone, at which point all pile 
driving activities would be halted, except in the case of impact 
driving when driving will be allowed to continue. Monitoring will take 
place from thirty minutes prior to initiation through thirty minutes 
post-completion of pile driving activities. Pile driving activities 
include the time to remove a single pile or series of piles, as long as 
the time elapsed between uses of the pile driving equipment is no more 
than thirty minutes.
    The following additional measures apply to visual monitoring:
    (1) Monitoring will be conducted by qualified observers, who will 
be placed at the best vantage point(s) practicable to monitor for 
marine mammals and implement shutdown/delay procedures when applicable 
by calling for the shutdown to the hammer operator. Qualified observers 
are trained biologists, with the following minimum qualifications:
    (a) Visual acuity in both eyes (correction is permissible) 
sufficient for discernment of moving targets at the water's surface 
with ability to estimate target size and distance; use of binoculars 
may be necessary to correctly identify the target;
    (b) Advanced education in biological science or related field 
(undergraduate degree or higher required);
    (c) Experience and ability to conduct field observations and 
collect data according to assigned protocols (this may include academic 
experience);
    (d) Experience or training in the field identification of marine 
mammals, including the identification of behaviors;
    (e) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    (f) Writing skills sufficient to prepare a report of observations 
including but not limited to the number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates and times when in-water construction activities were 
suspended to avoid potential incidental injury from construction sound 
of marine mammals observed within a defined shutdown zone; and marine 
mammal behavior; and
    (g) Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    (2) Prior to the start of pile driving activity, the shutdown zone 
will be monitored for 30 minutes to ensure that it is clear of marine 
mammals. Pile driving will only commence once observers have declared 
the shutdown zone clear of marine mammals; animals will be allowed to 
remain in the shutdown zone (i.e., must leave of their own volition) 
and their behavior will be monitored and documented. The shutdown zone 
may only be declared clear, and pile driving started, when the entire 
shutdown zone is visible (i.e., when not obscured by dark, rain, fog, 
etc.).
    If a marine mammal approaches or enters the shutdown zone during 
the course of vibratory pile driving operations, activity will be 
halted and delayed until he animal has voluntarily left and been 
visually confirmed beyond the shutdown zone. If a marine mammal is seen 
above water and then dives below, the contractor would wait 15 minutes 
for pinnipeds and harbor porpoise and 30 minutes for gray whale. If no 
marine mammals are seen by the observer in that time it will be assumed 
that the animal has moved beyond the exclusion zone.
    Monitoring will be conducted throughout the time required to drive 
a pile. In impact driving situations, once the pile driving of a 
segment begins it will not be stopped until that segment has reached 
its predetermined depth due to the nature of the sediments underlying 
the Bay. If impact pile driving were to stop and then resumes, it would 
potentially have to occur for a longer time and at increased energy 
levels. If marine mammals enter the safety zone after pile driving of a 
segment has begun, pile driving will continue and marine mammal 
observers will monitor and record marine mammal numbers and behavior.
    (3) The area within the Level B harassment zone shall be conducted 
by a minimum of three qualified NMFS-approved marine mammal observers 
(MMOs) placed in strategic locations that will afford visual coverage 
of these zones. Observers may be stationed on boats, Yerba Buena Island 
and/or Treasure Island, the new bridge or construction barges. Marine 
mammal presence within the Level B harassment zone will be monitored, 
but vibratory and impact pile driving as well as dismantling activity 
will not be stopped if marine mammals are found to be present. Any 
marine mammal documented within the Level B harassment zone during 
vibratory and impact driving or mechanical dismantling activities would 
constitute a Level B take (harassment), and will be recorded and 
reported as such.

Mitigation Conclusions

    We have carefully evaluated CALTRANS' proposed mitigation measures 
and considered their effectiveness in past implementation to determine 
whether they are likely to effect 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: (1) The manner in which, 
and the degree to which, the successful implementation of the measure 
is expected to minimize adverse impacts to marine mammals, (2) the 
proven or likely efficacy of the specific measure to minimize adverse 
impacts as planned; and (3) the practicability of the measure for 
applicant implementation.
    Any mitigation measure(s) we prescribe 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 number (total number or number at 
biologically

[[Page 43715]]

important time or location) of individual marine mammals exposed to 
stimuli expected to result in incidental take (this goal may contribute 
to 1, above, or to reducing takes by behavioral harassment only).
    (3) A reduction in the number (total number or number at 
biologically important time or location) of times any individual marine 
mammal would be exposed to stimuli expected to result in incidental 
take (this goal may contribute to 1, above, or to reducing takes by 
behavioral harassment only).
    (4) A reduction in the intensity of exposure to stimuli expected to 
result in incidental take (this goal may contribute to 1, above, or to 
reducing the severity of behavioral harassment only).
    (5) Avoidance or minimization of adverse effects to marine mammal 
habitat, paying particular attention to the prey base, blockage or 
limitation of passage to or from biologically important areas, 
permanent destruction of habitat, or temporary 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 CALTRANS' proposed measures, including 
information from monitoring of implementation of mitigation measures 
very similar to those described here under previous IHAs from other 
marine construction projects, we have determined that the proposed 
mitigation measures provide the means of effecting the least 
practicable impact on marine mammal species or stocks and their 
habitat, paying particular attention to rookeries, mating grounds, and 
areas of similar significance.

Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth ``requirements pertaining to 
the monitoring and reporting of such taking''. The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
incidental take authorizations 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.
    Any monitoring requirement we prescribe should improve our 
understanding of one or more of the following:
    (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.
    CALTRANS has submitted monitoring reports for each of the IHAs that 
have been issued to them for this project. NMFS received the most 
recent report on April 28, 2015 covering the IHA issued for the period 
between January 8, 2014 and January 7, 2015. CALTRANS observed all 
required monitoring and mitigation protocols during this period. 
Recorded takes were below permitted levels for all species except for 
harbor seals. After extrapolating observed numbers during 30 percent of 
driving activities, CALTRANS determined that 130 harbor seals were 
taken. This exceeded the allowable take limit of 50 stated in the IHA. 
CALTRANS reported that most of these seals were within the ZOI in Coast 
Guard Cove and Clipper Cove north of Yurba Buena Island (YBI) as well 
as an area 200-400 m off the southeast shore of YBI. Most seals 
appeared to be foraging and none showed any response to pile driving 
noise and continued to forage in those areas for up to several hours 
during pile driving. Based on the high number of harbor seal takes 
recorded, CALTRANS has requested an increase in takes under the IHA 
discussed in this Federal Register Notice. NMFS has approved an 
increase in harbor seal takes, which is discussed in a following 
section.
    CALTRANS consulted with NMFS to create a marine mammal monitoring 
plan as part of the IHA application for this project.

Visual Marine Mammal Observations

     CALTRANS will implement onsite marine mammal monitoring 
for 100% of all unattenuated impact pile driving of H-piles for 180- 
and 190-dB re 1 [mu]Pa exclusion zones (235 meter radius) and 160-dB re 
1 [mu]Pa Level B harassment zone, attenuated impact pile driving 
(except pile proofing) and mechanical dismantling for 180- and 190-dB 
re 1 [mu]Pa exclusion zones. CALTRANS will also monitor 20% of the 
attenuated impact pile driving for the 160-dB re 1 [mu]Pa Level B 
harassment zone (1,000 meter radius), and 20% of vibratory pile driving 
and mechanic dismantling for the 120-dB re 1 [mu]Pa Level B harassment 
zone (2,000 meter radius).
     Three individuals meeting the minimum qualification 
previously identified will monitor the Level A and B harassment zones 
during impact pile driving and the Level B harassment zone during 
vibratory pile driving and dismantling. Monitors may be stationed on 
boats, Yerba Buena Island and/or Treasure Island, the new bridge or 
construction barges.
     During impact pile driving, the area within 235 meters of 
pile driving activity will be monitored and maintained as marine mammal 
buffer area in which pile installation will not commence if any marine 
mammals are observed within or approaching the area of potential 
disturbance. If a marine mammal approaches or appears within the zone, 
pile driving of a segment will continue until that segment has reached 
its predetermined depth due to the nature of the sediments underlying 
the Bay.
     The area within the Level B harassment threshold for 
impact driving will be monitored by three field monitors stationed in a 
positon permitting visual access to the 1,000 meter limit of the Level 
B harassment zone. Marine mammal presence within this Level B 
harassment zone, if any, will be monitored, but impact pile driving 
activity will not be stopped if marine mammals are found to be present. 
Any marine mammal

[[Page 43716]]

documented within the Level B harassment zone during impact driving 
would constitute a Level B take (harassment), and will be recorded and 
reported as such.
     During vibratory pile driving, the area within 10 meters 
of pile driving activity will be monitored and maintained as a marine 
mammal buffer area in which pile installation will not commence or will 
be suspended temporarily if any marine mammals are observed within or 
approaching the area of potential disturbance. The Level B harassment 
area with a 2,000 meter radius will be monitored by three qualified 
observers stationed at strategic locations that provide adequate visual 
coverage of the disturbance zone. The monitoring staff will record any 
presence of marine mammals by species, will document any behavioral 
responses noted, and record Level B takes when sightings overlap with 
pile installation activities.
     During mechanical dismantling activities a 100 meters 
radius will be monitored and maintained as a marine mammal buffer area 
in which pile installation will not commence or will be suspended 
temporarily if any marine mammals are observed within or approaching 
the area.
     The individuals will scan the waters within each 
monitoring zone activity using binoculars (Vector 10X42 or equivalent), 
spotting scopes (Swarovski 20-60 zoom or equivalent), and visual 
observation.
     The area within which the Level B harassment thresholds 
could be exceeded during impact pile driving and vibratory pile driving 
will be monitored for the presence of marine mammals during all impact 
and vibratory pile driving. Marine mammal presence within these zones, 
if any, will be monitored but pile driving activity will not be stopped 
if marine mammals were found to be present. Any marine mammal 
documented within the Level B harassment zone will constitute a Level B 
take, and will be recorded and used to document the number of take 
incidents.
     If waters exceed a sea-state which restricts the 
observers' ability to make observations within the marine mammal buffer 
zone (the 235 meter radius) (e.g., excessive wind or fog), impact pile 
installation will cease until conditions allow the resumption of 
monitoring.
     The waters will be scanned for 30 minutes before, during, 
and 30 minutes after any and all pile driving and removal activities.
     If marine mammals enter or are observed within the 
designated marine mammal buffer zone (the 235m radius) during or 30 
minutes prior to pile driving, the monitors will notify the on-site 
construction manager to not begin until the animal has moved outside 
the designated radius.
     If a marine mammal approaches the Level A harassment zone 
prior to initiation of pile driving, CALTRANS cannot commence 
activities until the marine mammal (a) is observed to have left the 
Level A harassment zone or (b) has not been seen or otherwise detected 
within the Level A harassment zone for 30 minutes.
     The waters will continue to be scanned for at least 30 
minutes after pile driving has completed each day, and after each 
stoppage of 30 minutes or greater.

Data Collection

    We require that observers use approved data forms. Among other 
pieces of information, CALTRANS will record detailed information about 
any implementation of shutdowns, including the distance of animals to 
the pile and description of specific actions that ensued and resulting 
behavior of the animal, if any. In addition, CALTRANS will attempt to 
distinguish between the number of individual animals taken and the 
number of incidents of take. We require that, at a minimum, the 
following information be collected on the sighting forms:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Weather parameters (e.g., percent cover, visibility);
     Water conditions (e.g., sea state, tide state);
     Species, numbers, and, if possible, sex and age class of 
marine mammals;
     Description of any observable marine mammal behavior 
patterns, including bearing and direction of travel and distance from 
pile driving activity;
     Distance from pile driving activities to marine mammals 
and distance from the marine mammals to the observation point;
     Locations of all marine mammal observations; and
     Other human activity in the area.

Reporting

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

Estimated Take by Incidental Harassment

    Except with respect to certain activities not pertinent here, 
section 3(18) of 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].''
    All anticipated takes would be by Level B harassment resulting from 
impact and vibratory pile driving/removal and involving temporary 
changes in behavior. Injurious or lethal takes are not expected due to 
the expected source levels and sound source characteristics associated 
with the activity, and the planned mitigation and monitoring measures 
are expected to further minimize the possibility of such take.
    Given the many uncertainties in predicting the quantity and types 
of impacts of sound in every given situation on marine mammals, it is 
common practice to estimate how many animals are likely to be present 
within a particular distance of a given activity, or exposed to a 
particular level of sound, based on the available science.

[[Page 43717]]

    This practice potentially overestimates the numbers of marine 
mammals taken for stationary activities, as it is likely that some 
smaller number of individuals may accrue a number of incidences of 
harassment per individual than for each incidence to accrue to a new 
individual, especially if those individuals display some degree of 
residency or site fidelity and the impetus to use the site (e.g., 
because of foraging opportunities) is stronger than the deterrence 
presented by the harassing activity.
    CALTRANS has requested authorization for the incidental taking of 
small numbers of California sea lions (Zalophus californianus), Pacific 
harbor seals (Phoca vitulina richardsii), harbor porpoises (Phocoena 
phocoena), and gray whales (Eschrichtius robustus) incidental to 
construction associated with a replacement bridge for the East Span of 
the SF-OBB, in San Francisco Bay (SFB, or Bay), California.
    In order to estimate the potential incidents of take that may occur 
incidental to the specified activity, we must first estimate the extent 
of the sound field that may be produced by the activity and then 
consider in combination with information about marine mammal density or 
abundance in the project area. We provided detailed information on 
applicable sound thresholds for determining effects to marine mammals 
as well as describing the information used in estimating the sound 
fields, the available marine mammal density or abundance information, 
and the method of estimating potential incidences of take, in our 
Federal Register notice of proposed authorization (80 FR 23744; March 
20, 2015).
    Table 1 illustrated the 190 dB rms Level A harassment (injury) 
threshold for underwater noise for pinniped species could be exceeded 
at a distance of up to approximately 95 meters during impact pile 
driving activities, and the 180 dB rms Level A harassment (injury) 
threshold for cetacean species could be exceeded at a distance of up to 
approximately 235 meters during impact pile driving activities. 
Additionally, the 160 dB rms Level B harassment (behavioral disruption) 
threshold for impulsive source underwater noise for pinniped and 
cetacean species could be exceeded at a distance of up to approximately 
1,000 meters during impact pile driving and the 120 dB Level B 
harassment threshold could be exceeded at 2,000 meters. Note that the 
actual area insonified by pile driving activities is significantly 
constrained by local topography relative to the identified threshold 
radii.
    Marine mammal density estimates were based on marine mammal 
monitoring reports and marine mammal observations made during pile 
driving activities associated with the SF-OBB construction work 
authorized under prior IHAs. Pacific harbor seal densities were 
calculated and described in the Federal Register notice of proposed 
authorization (80 FR 23744; March 20, 2015). During monitoring for the 
East Span of the SF-OBB, there were 657 observations of harbor seals 
made during over 210 days from 2000 to 2014. Two densities were 
calculated because of the higher density of seals observed foraging 
near YBI and Treasure Island. Foraging seals tended to remain in the 
area for several hours while transiting seals passing under the SF-OBB 
were only observed 1-2 times. Therefore, densities east of Pier E3-E8 
are much lower than the density than west of Pier E3.
    The area of 2,000-meter threshold for the Level B behavioral 
harassment zone is 12.57 km\2\ (12,570,000 m\2\). Half of that area to 
the west of Piers E3-E8 (6.29 km\2\) would have a higher density of 
harbor seals which are frequently observed in the three foraging areas. 
The range of seals observed within the foraging areas is 0-8 seals and 
the mean is 3.6 seals per day (combined for all three areas). The other 
half of the Level B harassment zone would have a lower density due to 
the infrequent observations of seals moving through the area. In 
addition the density of seals will vary with season therefore a density 
for the spring-summer season when seals spend more time onshore as they 
are pupping and molting and the fall/winter season.
    This estimate of 460 harbor seal takes is above the number of seals 
that have been permitted for take in previous IHAs that have been 
issued related to this project. However, the estimate presented here 
represents a more complete picture of the marine mammal density in the 
project area and the potential for exposure to project activities.
    California sea lions are based on CALTRANS observations over 15 
years of monitoring on the Bay Bridge, 2000 to 2014, including baseline 
monitoring in 2003 before bridge construction began. It should be noted 
that monitoring was not year round and there was little monitoring 
required during the period of mid-2010 to mid-2013 due to no pile 
driving. During 2013 and 2014, there was a large increase in pile 
driving to construct temporary falsework and for mechanical dismantling 
so the current estimates of animals do include recent monitoring. 
California sea lion numbers fluctuate from year to year. For example, 
in 2014 no sea lions were observed in the harassment zone while in 
2004, 36 sea lions were recorded near the Bay Bridge construction areas 
during pile driving. The larger number of sea lions in 2004 was 
probably related to a run of herring that was near the Bay Bridge and 
sea lions were observed feeding on dense aggregations of herring in the 
area. Therefore, an allowed take 50 sea lions is considered a 
conservative estimate.
    Harbor porpoises were observed near the tower of the new Bay Bridge 
in 2013 and 2014. Each of those was a single animal and far out of 
their normal range for the Bay. If 1 or 2 pods of porpoises were to 
enter the construction area, then there might be up to 6 takes (pod 
size of 2-3 porpoises). Based on this NMFS believes that an allowed 
take of up to 10 harbor porpoises is conservative, but reasonable.
    Gray whale take estimates were based on sighting reports collected 
by the Marine Mammal Center in Sausalito (the NMFS stranding facility 
for northern California). The Center collects whale sightings 
information from the general public, researchers, and the U.S. Coast 
Guard. For the gray whale, 5 permitted takes is likely to be a 
conservative, but reasonable, estimate as they have never been observed 
within any of the behavioral zones during monitoring. Additionally, 
there has only been one report of a gray whale swimming under the 
original East Span of the Bay Bridge a number of years ago.
    Based on these results, and accounting for a certain level of 
uncertainty regarding the next phase of construction, NMFS concludes 
that at maximum 460 harbor seals, 50 California sea lions, 10 harbor 
porpoises, and 5 gray whales could be exposed to noise levels that 
could cause Level B harassment as a result of the CALTRAN' SF-OBB 
construction activities. These numbers represent 1.5%, <0.01%, <0.01% 
and 0.10% of the California stock harbor seal, the U.S. stock 
California sea lion, the Eastern North Pacific stock gray whale, and 
the San Francisco-Russian River stock harbor porpoise, respectively 
(Table 2).

[[Page 43718]]



 Table 2--Estimates of the Possible Maximum Numbers of Marine Mammals Taken by Level B Harassment as a Result of
                              the Proposed CALTRANS' SF-OBB Construction Activities
----------------------------------------------------------------------------------------------------------------
                                                                                                      Percent
                  Species                                   Stocks                 Level B takes    population
----------------------------------------------------------------------------------------------------------------
                                                    Pinnipeds
----------------------------------------------------------------------------------------------------------------
Harbor seal................................  California.........................             460             1.5
California sea lion........................  U.S................................              50           <0.01
----------------------------------------------------------------------------------------------------------------
                                                    Cetaceans
----------------------------------------------------------------------------------------------------------------
Gray whale.................................  Eastern North Pacific..............               5           <0.01
Harbor porpoise............................  San Francisco-Russian River........              10            0.10
----------------------------------------------------------------------------------------------------------------

Analyses and Determinations

Negligible Impact Analysis

    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, effects on habitat, and the status 
of the species.
    To avoid repetition, the discussion of our analyses applies to all 
the species listed in Table 2, given that the anticipated effects of 
this pile driving project on marine mammals are expected to be 
relatively similar in nature. There is no information about the size, 
status, or structure of any species or stock that would lead to a 
different analysis for this activity.
    Pile driving, pile removal and mechanical dismantling activities 
associated with the construction of a replacement bridge for the East 
Span of the SF-OBB, as outlined previously, have the potential to 
disturb or displace marine mammals. Specifically, the specified 
activities may result in take, in the form of Level B harassment 
(behavioral disturbance) only, from underwater sounds generated from 
pile driving. Potential takes could occur if individuals of these 
species are present in the ensonified zone when pile driving and 
removal are happening.
    No injury, serious injury, or mortality is anticipated given the 
nature of the activity and measures designed to minimize the 
possibility of injury to marine mammals. The known potential for 
serious injury or mortality is minimized through the construction 
method and the implementation of the planned mitigation measures. Both 
vibratory hammers and impact hammers will be utilized based on local 
substrate conditions. Vibratory driving will be used wherever 
conditions are favorable for this technique. Vibratory driving does not 
have significant potential to cause injury to marine mammals due to the 
relatively low source levels produced and the lack of potentially 
injurious source characteristics. Impact pile driving produces short, 
sharp pulses with higher peak levels and much sharper rise time to 
reach those peaks. When impact driving is necessary, required measures 
(implementation of shutdown zones) significantly reduce any possibility 
of injury. Given sufficient ``notice'' through use of soft start (for 
impact driving), marine mammals are expected to move away from a sound 
source that is annoying prior to its becoming potentially injurious. 
The likelihood that marine mammal detection ability by trained 
observers is high under the environmental conditions described for this 
area of San Francisco Bay further enables the implementation of 
shutdowns to avoid injury, serious injury, or mortality.
    Effects on individuals that are taken by Level B harassment, on the 
basis of reports in the literature as well as monitoring from other 
similar activities, will likely be limited to reactions such as 
increased swimming speeds, increased surfacing time, or decreased 
foraging (if such activity were occurring) (e.g., Thorson and Reyff, 
2006; HDR, 2012; Lerma, 2014). Most likely, individuals will simply 
move away from the sound source and be temporarily displaced from the 
areas of pile driving, although even this reaction has been observed 
primarily only in association with impact pile driving. In response to 
vibratory driving, pinnipeds (which may become somewhat habituated to 
human activity in industrial or urban waterways) have been observed to 
orient towards and sometimes move towards the sound. The pile driving 
activities analyzed here are similar to, or less impactful than, 
numerous construction activities conducted in other similar locations, 
which have taken place with no reported injuries or mortality to marine 
mammals, and no known long-term adverse consequences from behavioral 
harassment. Repeated exposures of individuals to levels of sound that 
may cause Level B harassment are unlikely to result in hearing 
impairment or to significantly disrupt foraging behavior. Thus, even 
repeated Level B harassment of some small subset of the overall stock 
is unlikely to result in any significant realized decrease in fitness 
for the affected individuals, and thus would not result in any adverse 
impact to the stock as a whole. Level B harassment will be reduced to 
the level of least practicable impact through use of mitigation 
measures described herein and, if sound produced by project activities 
is sufficiently disturbing, animals are likely to simply avoid the 
project area while the activity is occurring.
    CALTRANS' proposed activities are localized and of short duration. 
The entire project area is limited to the East Span of the bridge and 
its immediate surroundings. The project will require the installation 
of a total of approximately 200 piles. Impact driving of pipe piles 
will be limited to a maximum of 20 piles per day and proofing of the 
pipe piles will not exceed a maximum of 2 piles per day--each pile 
would be driven with no more than 20 blows during a one-minute

[[Page 43719]]

period. Total hammer time is scheduled to occur over 128 days between 
July 15, 2015 and July 14, 2016. These localized and short-term noise 
exposures may cause brief startle reactions or short-term behavioral 
modification by the animals. These reactions and behavioral changes are 
expected to subside quickly when the exposures cease. Moreover, the 
proposed mitigation and monitoring measures are expected to reduce 
potential exposures and behavioral modifications even further. 
Additionally, no important feeding and/or reproductive areas for marine 
mammals are known to be near the proposed action area. Therefore, the 
take resulting from this CALTRANS project is not reasonably expected to 
and is not reasonably likely to adversely affect the marine mammal 
species or stocks through effects on annual rates of recruitment or 
survival and, therefore, will have a negligible impact on the affected 
species or stocks.
    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. The 
project activities would not modify existing marine mammal habitat. The 
activities may cause some fish to leave the area of disturbance, thus 
temporarily 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.
    In summary, this negligible impact analysis is founded on the 
following factors: (1) The possibility of injury, serious injury, or 
mortality may reasonably be considered discountable; (2) the 
anticipated incidents of Level B harassment consist of, at worst, 
temporary modifications in behavior with no significant adverse impacts 
on habitat and; (3) the presumed efficacy of the proposed mitigation 
measures in reducing the effects of the specified activity to the level 
of least practicable impact. In combination, we believe that these 
factors, as well as the available body of evidence from other similar 
activities, demonstrate that the potential effects of the specified 
activity will have only short-term effects on individuals. The 
specified activity is not expected to impact rates of recruitment or 
survival and will therefore not result in population-level impacts.
    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 proposed monitoring and 
mitigation measures, NMFS finds that the total marine mammal take from 
CALTRANS' construction of a replacement bridge for the East Span of the 
SF-OBB will have a negligible impact on the affected marine mammal 
species or stocks.

Small Numbers Analysis

    Table 2 demonstrates the number of animals that could be exposed to 
received noise levels that could cause Level B behavioral harassment 
for the proposed work associated with the replacement bridge 
construction. These numbers represent 1.5%, <0.01%, <0.01% and 0.10% of 
the California stock harbor seal, the U.S. stock California sea lion, 
the Eastern North Pacific stock gray whale, and the San Francisco-
Russian River stock harbor porpoise, respectively (Table 3).
    The numbers of animals authorized to be taken for all species are 
small relative to the relevant stocks or populations even if each 
estimated taking occurred to a new individual--an extremely unlikely 
scenario. For pinnipeds occurring in the vicinity of the SF-OBB 
project, there will almost certainly be some overlap in individuals 
present day-to-day, and these takes are likely to occur only within 
some small portion of the overall regional stock, such as the number of 
harbor seals that regularly use nearby haul-out rocks.
    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, which are expected to reduce the number of marine mammals 
potentially affected by the proposed action, 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 proposed 
project area; and, thus, no subsistence uses impacted by this action.

Endangered Species Act (ESA)

    No marine mammal species listed under the ESA are expected to be 
affected by these activities. Therefore, we have determined that a 
section 7 consultation under the ESA is not required.

National Environmental Policy Act (NEPA)

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

Authorization

    As a result of these determinations, we have issued an IHA to 
CALTRANS for conducting the described activities related to the 
construction of the East Span of the San Francisco-Oakland Bay Bridge, 
from July 15, 2015 through July 14, 2016 provided the previously 
described mitigation, monitoring, and reporting requirements are 
incorporated.

    Dated: July 16, 2015.
Perry Gayaldo,
Deputy Director, Office of Protected Resources, National Marine 
Fisheries Service.
[FR Doc. 2015-18021 Filed 7-22-15; 8:45 am]
 BILLING CODE 3510-22-P