[Federal Register Volume 82, Number 107 (Tuesday, June 6, 2017)]
[Notices]
[Pages 26063-26079]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-11646]


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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XF411


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

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

ACTION: Notice; proposed incidental harassment authorization; request 
for comments and information.

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SUMMARY: NMFS has received a request from the California Department of 
Transportation (CALTRANS) for an incidental take authorization to take 
small numbers of six species of marine mammals, by harassment, 
incidental to the dismantling of the original East Span of the San 
Francisco-Oakland Bay Bridge (SFOBB) in the San Francisco Bay (SFB), 
California. Pursuant to the Marine Mammal Protection Act (MMPA), NMFS 
is requesting comments on its proposal to issue an incidental 
harassment authorization (IHA) to incidentally take marine mammals 
during the specified activities.

DATES: Comments and information must be received no later than July 6, 
2017.

ADDRESSES: Comments on the application should be addressed to Jolie 
Harrison, Chief, Permits and Conservation Division, Office of Protected 
Resources, National Marine Fisheries Service, 1315 East-West Highway, 
Silver Spring, MD 20910 and electronic comments should be sent to 
[email protected].
    Instructions: NMFS is not responsible for comments sent by any 
other method, to any other address or individual, or received after the 
end of the comment period. Comments received electronically, including 
all attachments, must not exceed a 25-megabyte file size. Attachments 
to electronic comments will be accepted in Microsoft Word or Excel or 
Adobe PDF file formats only. All comments received are a part of the 
public record and will generally be posted online at http://www.nmfs.noaa.gov/pr/permits/incidental/construction.htm without 
change. All personal identifying information (e.g., name, address, 
etc.) voluntarily submitted by the commenter may be publicly 
accessible. Do not submit confidential business information or 
otherwise sensitive or protected information.

FOR FURTHER INFORMATION CONTACT: Dale Youngkin, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of references cited in this 
document, may be obtained at www.nmfs.noaa.gov/pr/permits/incidental/construction.htm. In case of problems accessing these documents, please 
call the contact listed above.

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.
    The MMPA states that the term ``take'' means to harass, hunt, 
capture, kill, or attempt to harass, hunt, capture, or kill any marine 
mammal.
    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

[[Page 26064]]

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

Summary of Request

    On April 5, 2017, CALTRANS submitted a request to NMFS for an IHA 
to take marine mammals incidental to the dismantling of the original 
East Span of the SFOBB in the San Francisco Bay. On May 1, 2017, NMFS 
deemed the application adequate and complete. CALTRANS requested 
authorization for incidental take by harassment only and NMFS concurs 
that mortality is not expected to result from this activity. NMFS is 
proposing to issue an IHA that will authorize take by Level B 
harassment of Pacific harbor seal, California sea lion, northern 
elephant seal, northern fur seal, harbor porpoise, and bottlenose 
dolphin incidental to CALTRANS' activities. As described in the 
Overview section, previous IHAs have been issued to CALTRANS for 
similar activities, specifically for the use of mechanical dismantling 
and controlled blasts to implode piers of the original East Span of the 
SFOBB.

Description of the Specified Activity

Overview

    CALTRANS proposes removal of the original East Span of the SFOBB by 
mechanical dismantling and by use of controlled charges to implode 13 
piers (Piers E6-E18) into their open cellular chambers below the 
mudline. Activities associated with dismantling the original East Span 
may potentially result in incidental take of marine mammals due to the 
use of highly controlled charges to dismantle the marine foundations of 
the piers.
    Several previous one-year IHAs have been issued to CALTRANS for 
pile driving/removal and construction of the new SFOBB East Span 
beginning in 2003. NMFS has issued 10 IHAs to CALTRANS for the SFOBB 
Project. The first five IHAs (2003, 2005, 2007, 2009, and 2011) 
addressed potential impacts associated with pile driving for the 
construction of the new East Span of the SFOBB. IHAs issued in 2013, 
2014 and July 2015 addressed activities associated with both 
constructing the new East Span and dismantling the original East Span, 
specifically addressing vibratory pile driving, vibratory pile 
extraction/removal, attenuated impact pile driving, pile proof testing, 
and mechanical dismantling of temporary and permanent marine 
foundations. On September 9, 2015, NMFS issued an IHA to CALTRANS for 
incidental take associated with the demolition of Pier E3 of the 
original SFOBB by highly controlled explosives (80 FR 57584; September 
24, 2015). On September 30, 2016, NMFS issued an IHA authorizing the 
incidental take of marine mammals associated with both pile driving/
removal and controlled implosion of Piers E4 and E5 (81 FR 67313). 
CALTRANS is requesting this IHA to continue dismantling the original 
East Span of the SFOBB using mechanical means as well as five to six 
implosion events to dismantle 13 piers (Piers E6-E18). CALTRANS does 
not anticipate any further in-water pile installation or pile removal 
for the SFOBB project, and is not requesting coverage under this IHA to 
conduct pile driving/removal activities.

Dates and Duration

    The demolition of Piers E6 through E18 through controlled implosion 
are planned to begin in September 2017. Implosion events would consist 
of the use of highly controlled charges to implode 1 to 4 piers per 
event, amounting to a total of 5 to 6 implosion events to dismantle the 
13 piers (Piers E6-E18). CALTRANS is requesting issuance of an IHA for 
a period of one year. Therefore, an IHA, if issued, would cover the 
period from September 1, 2017 through August 31, 2018.

Specified Geographic Region

    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 feet (ft) (400 meters (m)) 
west of the Bay Bridge toll plaza, where the new and former spans 
connect with land at the Oakland Touchdown (OTD) in the city of 
Oakland.

Detailed Description of the Specified Activities

    CALTRANS proposes the removal of Piers E6 through E18 (13 piers) of 
the original East Span by use of mechanical dismantling and 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 2015 Pier E3 Demonstration 
Project implosion, as well as the results from the 2016 implosions of 
Piers E4 and E5, support the use of controlled charges as a more 
expedient method of removal that will cause less environmental impact 
compared to mechanical methods using a dry (fully dewatered) cofferdam.
    Piers E6 through E18 of the original East Span are located between 
the OTD area and YBI, and just south of the SFOBB new East Span. These 
piers consist of lightly reinforced concrete cellular structures that 
are supported by timber piles driven into the Bay mud and occupy areas 
below the mudline, within the water column, and above the water line of 
the Bay. Unlike Piers E3, E4, and E5, which were dismantled using 
highly controlled charges previously, Piers E6 through E18 do not 
extend deep below the mudline. The timber piles and concrete slabs that 
are below approved removal limits will remain in place. Piers E6, E7, 
and E8 supported the 504-ft bridge spans of the original SFOBB. Pier E9 
is located at the connection point between the 504-ft bridge spans and 
the 288-ft bridge spans. Piers E10 through E18 supported the original 
SFOBB 288-ft bridge spans.
    The use of controlled charges would greatly reduce in-water work 
periods and shorten the overall duration of marine foundation removal 
compared with mechanical removal. Because of the similar structures for 
each pier, each would be removed following the same five steps:
     Mechanical dismantling of the pier cap and concrete 
pedestals;
     Drilling bore holes into the marine foundation;
     Installing and testing the BAS;
     Installing charges, activating the BAS, and imploding the 
pier; and
     Managing and removing remaining dismantling debris.
    Details of these steps are provided below.
Mechanical Dismantling of Concrete Pedestals and Pier Caps
    For all piers, support barges will be used to move hydraulic 
excavators equipped with hoe rams, shearing attachments, drills, saws, 
and other equipment including cutting lances and torches to be used 
during the mechanical dismantling. A barge-mounted crane will be used 
to move equipment onto and off each pier.
    For all piers, the concrete pedestals and pier cap will be removed 
by mechanical means using tools including those listed above to break 
the concrete structure to pieces. Concrete rubble and rebar will be 
managed using excavators and cranes that will be mounted with buckets. 
Throughout concrete dismantling operations on each pier, support 
platforms will be installed to provide a working surface for the

[[Page 26065]]

excavators to dismantle the upper portion of the pier. The support 
platforms will be made up of timber crane mats. A debris catchment 
system, accepted by the San Francisco Regional Water Quality Control 
Board, will be in place to contain concrete debris from discharging 
into the Bay during dismantling operations.
    All concrete rubble from mechanical dismantling of concrete 
pedestals will be taken off-site for disposal. Rubble will be loaded 
onto receiving barges to be taken to Berth 9 in the Port of Oakland to 
be sorted and disposed of at an approved upland facility. The pier caps 
covering the central chambers will be dismantled last and will be 
broken with a ram hoe. The broken pier caps will remain in the hollow 
void during the controlled blasting, and all other mechanical 
dismantling activities would occur above the waterline.
Drill Boreholes
    After the mechanical dismantling operations are complete, access 
platforms will be installed on top of each pier to support the drilling 
equipment. The exposed interior cell walls, buttress walls, and outside 
walls will be drilled from the top down, to remove concrete and create 
boreholes to just below the controlled blasting removal limit for each 
pier. Boreholes that are drilled in areas that are inundated with water 
(i.e., to the buttress walls and concrete slabs) will be done using a 
drill bit working within a tubular casing for guidance and to provide 
containment during in-water work. Monitoring will be performed to 
minimize and avoid impacts on water quality during this activity.
    Pier 9 has additional buttress walls compared to other piers. 
Drilling holes for buttress walls on Pier 9 will be done by the same 
method that was used for the buttress wall of Pier 3 (Demonstration 
Project). Divers will cut notches into the buttress walls and will 
install conduit to the work platform on top of the pier. The drilling 
will be done within the casings from the work platform.
Blast Attenuation System (BAS) Installation and Deployment
    The BAS that will be used at Piers E6 to E 18 is the same system 
that was successfully used for Piers E3 (Demonstration Project), E4, 
and E5. The BAS is a modular system of pipe manifold frames, placed 
around each pier and fed by air compressors to create a curtain of air. 
The BAS will be activated before and during implosion. As shown during 
previous implosions, the BAS will help minimize noise and pressure 
waves generated during each controlled blast, to minimize potentially 
adverse effects on biological resources. Each BAS frame is 
approximately 50.5 ft (15.4 m) long by 6 ft (1.8 m) wide. The BAS to be 
used at Piers E6 through E18 will be same system that was used at Piers 
E3, E4, and E5, and will meet the same specifications.
    To remove the 13 pier foundations of Piers E6 through E18 in 2017, 
multiple pier implosions may be performed on the same day, 
sequentially. Smaller piers will be combined into single blast events. 
The implosion of each pier within the blast events will be spaced 1 to 
5 seconds apart. All pier implosion events involving multiple piers 
will use fewer explosives and will have shorter blast durations than 
the previous implosion of Pier E3. Up to 2 piers that formerly 
supported either the 504-foot spans of the bridge may be imploded on 
the same day. Two to four small piers (that formerly supported the 288-
foot spans) may be imploded on the same day. A total of five to six 
pier implosion events, consisting of the implosion of one to four piers 
per event, may be required. An individual BAS will be installed around 
each pier included in a multiple-pier implosion event.
    The complete BAS will be installed and tested during the weeks 
leading up to each controlled blast. Before installing the BAS, 
CALTRANS will move any existing debris on the Bay floor that may 
interrupt proper installation of the BAS. Existing debris identified as 
a risk to proper installation of the BAS will be moved outside the path 
of the BAS layout. Each BAS frame will be lowered to the bottom of the 
Bay by a barge-mounted crane and positioned into place. Divers will be 
used to assist frame placement, and to connect air hoses to the frames. 
Frames will be situated to contiguously surround the pier. Each frame 
will be weighted to negative buoyancy for activation. Compressors will 
provide enough pressure to achieve a minimal air volume fraction of 
three to four percent, consistent with the successful use of BAS 
systems in past controlled blasting activities, including Pier E3 
(CALTRANS 2016 and CALTRANS 2017). System performance is anticipated to 
provide 70 to 80 percent sound and pressure attenuation, based on the 
results from the previous controlled blasting activities (CALTRANS 
2016, 2017).
Test Blasts
    At the beginning of the implosion season, test blasts will be 
conducted within the completely installed and operating BAS so that the 
hydroacoustic monitoring equipment will be properly triggered and 
functional before each pier implosion event. A key requirement of the 
implosion involves accurately capturing hydroacoustic information from 
the controlled blast. To accomplish this, a smaller test charge will be 
used to trigger recording instrumentation. Multiple test blast events 
may be required to verify proper instrument operation and calibrate the 
equipment for the implosion event. These same instruments and others of 
the same type will use high-speed recording devices to capture 
hydroacoustic data at both near-field and far-field monitoring 
locations during the implosion.
    Test charges will be scheduled to occur within two weeks of the 
first implosion scheduled for the implosion season and after the BAS is 
positioned into place and is functional. Additional test blasts may be 
needed prior to subsequent implosion events to ensure triggering of the 
data acquisition and recording instruments as well as calibration of 
the equipment. The BAS will be operational during all tests. Tests will 
use a charge weight of approximately 18 grains (0.0025 pound) or less. 
The test charge will be placed along one of the longer faces of the 
pier and inside the BAS while it is operating. Results from test blasts 
that occurred during the Piers E3-E5 indicate that these test blasts 
did not reach or exceed marine mammal threshold criteria beyond the 
bubble flux of the BAS (See Appendix A of the IHA application and 
CALTRANS 2016). Therefore, no take of marine mammals is anticipated due 
to test blasts.
Controlled Implosion of Piers E6 Through E18
    Before pier removal via controlled blasting, the bore holes in the 
pier will be loaded with controlled charges. Individual cartridge 
charges, using electronic blasting caps versus pumpable liquid blasting 
agents, have been selected to provide greater control and accuracy in 
determining the individual and total charge weights. Use of individual 
cartridges will allow a refined blast plan that efficiently breaks 
concrete while minimizing the amount of charges needed.
    Boreholes will vary in diameter and depth, and have been designed 
to provide optimal efficiency in transferring the energy created by the 
controlled charges to dismantle the pier. Individual charge weights 
will vary from 20 to 35 pounds (lbs) (9 to 16 kilograms (kg)), and the 
total charge weight for each controlled blast event will be 
approximately 2,132 to 15,800 lbs (967 to 7,167 kg). Depending on the

[[Page 26066]]

location, size, and removal limit of the pier to be removed, the total 
number of individual charges to be used will range from approximately 
100 to 455. The charges will be arranged in different levels (decks) 
and will be separated in boreholes by stemming, which is the insertion 
of inert materials (e.g., sand or gravel) to insulate and retain 
charges in an enclosed space. Stemming will allow more efficient 
transfer of energy into the structural concrete for fracture, and will 
further reduce the release of potential energy into the surrounding 
water column. The entire detonation sequence, consisting of 
approximately 100 to 455 detonations, will last approximately 1 to 4 
seconds for each pier with a minimum delay time of 9 milliseconds 
(msec) between detonations.
    Controlled blasting of Pier E6 will remove concrete by blasting 
down through the concrete slab and top 3 ft (1 m) of the concrete seal. 
Controlled blasting of Pier E7 will remove concrete by blasting down 
through the concrete slab but not the concrete seal. Controlled 
blasting of Piers E8 through E18 will remove concrete by blasting down 
through the concrete cellular structure, but not through the concrete 
slab, seal, and timber piles below. For Pier E6, site conditions will 
require the pier to be blasted further into the structure to remove the 
upper 3 ft (1 m) of the concrete seal and remove the structure to the 
approved removal elevation. Remaining concrete seals and timber piles 
below the mudline will not be removed.
    As stated above, to remove the 13 marine foundations of Piers E6 
through E18 in the 2017 season, multiple pier implosions may be 
performed on the same day, sequentially. Smaller piers will be combined 
into single blast events. All pier implosion events involving multiple 
piers will use fewer explosives and will have a shorter total blast 
duration than the previous implosion of Pier E3.
Debris Removal and Site Restoration
    Following the controlled implosion event and confirmation that the 
area is safe to work in, construction crews will begin to remove all 
associated equipment, including barges, compressors, the BAS, and blast 
mats. CALTRANS expects that a small portion of rubble from each pier 
will fall outside its respective footprint and/or mound within the 
footprint of each pier, and will need to be managed after each 
controlled implosion. The portions of each pier that do not break apart 
during controlled blasting and remain above the removal limits will be 
demolished by mechanical means. This may require the use of underwater 
mechanical equipment, including hydraulic crushing or grinding 
machinery or diver-operated jackhammers.
    Rubble from the controlled implosion of Piers E6 through E18 will 
be removed down to each pier's respective planned debris removal limit 
elevation by barge-mounted crane with a clamming bucket. The clamming 
bucket will be equipped with a GPS unit to accurately guide the 
movement of the bucket during underwater operation. The planned debris 
removal limit elevations are shown in Table 1.

       Table 1--Approximate Mudline and Removal Elevations of SFOBB Original East Span Marine Foundations
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                                                                                     Required
                                                                      Mudline         removal         Planned
                              Pier                                   elevation    elevation (1.5  removal limits
                                                                      (feet)         ft below       (3 ft below
                                                                                   mudline; ft)    mudline; ft)
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E6..............................................................           -40.0           -41.5           -43.0
E7..............................................................           -28.0           -29.5           -31.0
E8..............................................................           -19.0           -20.5           -22.0
E9..............................................................           -17.5           -19.0           -20.5
E10.............................................................           -18.0           -19.5           -21.0
E11.............................................................           -14.0           -15.5           -17.0
E12.............................................................           -14.0           -15.5           -17.0
E13.............................................................           -14.0           -15.5           -17.0
E14.............................................................           -15.0           -16.5           -18.0
E15.............................................................           -12.5           -14.0           -15.5
E16.............................................................           -12.5           -14.0           -15.5
E17.............................................................           -12.5           -14.0           -15.5
E18.............................................................           -12.5           -14.0           -15.5
----------------------------------------------------------------------------------------------------------------

    Proposed mitigation, monitoring, and reporting measures are 
described in detail later in this document (please see ``Proposed 
Mitigation'' and ``Proposed Monitoring and Reporting'').

Description of Marine Mammals in the Area of the Specified Activity

    Seven species, representing seven stocks, of marine mammals may be 
affected by the SFOBB project. 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, but are 
unlikely to occur near the project area during September, October, and 
November when pier implosions would take place. Therefore, no take of 
gray whales from the proposed pier implosions was requested, and NMFS 
is not proposing to authorize take of gray whales. 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.
    We have reviewed CALTRANS' species information, which summarizes 
available information regarding status and trends, distribution, and 
habitat preferences, behavior and life history, and auditory 
capabilities of the potentially affected species, for accuracy and 
completeness. We refer the reader to Chapters 3 and 4 of the CALTRANS 
IHA application as well as to NMFS' Stock Assessment Reports (SR; 
www.nmgs.noaa/.gov/pr/sars/), for detailed information. Additional 
general information about these species and

[[Page 26067]]

stocks (e.g., physical and behavioral descriptions) may be found on 
NMFS' Web site (www.nmfs.noaa.gov/pr/species/mammals/). Table 2 lists 
all species and stocks with potential for occurrence in the San 
Francisco Bay and summarizes information related to the species or 
stock, including potential biological removal (PBR). For taxonomy, we 
follow Committee on Taxonomy (2016). PBR is defined by the MMPA as the 
maximum number of animals, not including natural mortalities, that may 
be removed from a marine mammal stock while allowing that stock to 
reach or maintain its optimum sustainable population. PBR is considered 
in concert with the known sources of ongoing anthropogenic mortality to 
assess the population-level effects of the anticipated mortality from a 
specific project (as described in NMFS's SARs). While no mortality is 
anticipated or authorized here, PBR information is included here as a 
gross indicator of the status of the species and other threats. Gray 
whales are a species that could potentially occur in the proposed 
survey area but are not expected to have reasonable potential to be 
harassed by CALTRANS' SFOBB actions because they are unlikely to occur 
in the project area, as discussed above. This species is included in 
Table 2 but is omitted from further analysis. For species status, we 
provide information regarding U.S. regulatory status under the MMPA and 
ESA in Table 2.

                                        Table 2--Marine Mammal Species Potentially Present in Region of Activity
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                                              Potential
                                                                                                                                   Stock      biological
          Common name             Scientific name    ESA/MMPA status       Occurrence        Seasonality           Range         abundance     removal
                                                                                                                                                (PBR)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor seal (CA stock).........  Phoca vitulina     NL/ND............  Common...........  Year round.......  California.......       30,968        1,641
                                  richardii.
California sea lion (US stock).  Zalophus           NL/ND............  Common...........  Year round.......  California.......      296,750        9,200
                                  californianus.
Northern fur seal (CA stock)...  Callorhinus        NL/ND............  Rare.............  Year round.......  California.......       12,844          451
                                  ursinus.
Northern elephant seal (CA       Mirounga           NL/ND............  Occasional.......  Spring & fall....  California.......      179,000        4,882
 breeding stock).                 angustirostris.
Gray whale (Eastern north        Eschrichtius       NL*/ND...........  Rare.............  Spring & fall....  Mexico to the           20,990          624
 Pacific stock).                  robustus.                                                                   U.S. Arctic
                                                                                                              Ocean.
Harbor porpoise (SF-Russian      Phocoena phocoena  NL/ND............  Rare.............  Year round.......  California.......        9,886           66
 River stock).
Coastal Bottlenose dolphin (CA   Tursiops           NL/ND............  Rare.............  Year round.......  California.......          323          2.4
 coastal stock).                  truncatus.
--------------------------------------------------------------------------------------------------------------------------------------------------------
NL = Not Listed; * The E. North Pacific population is not listed under the ESA.; ND = Not Depleted under the MMPA.

Potential Effects of the Specified Activity on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that the 
specified activity may impact marine mammals and their habitat. 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 
``Negligible Impact Analysis and Determination'' section will consider 
the context of this section, the ``Estimated Take by Incidental 
Harassment'' section, and the ``Proposed Mitigation'' section to draw 
conclusions regarding the likely impacts of these activities on the 
reproductive success or survivorship of individuals and how those 
impacts on individuals are likely to impact marine mammal species 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. In 
August 2016, NMFS released its Technical Guidance for Assessing the 
Effects of Anthropogenic Sound on Marine Mammal Hearing (NMFS 2016 
Acoustic Technical Guidance). Under the NMFS 2016 Acoustic Technical 
Guidance, there are five marine mammal hearing group categories, with 
associated generalized hearing ranges as shown in Table 3 (note that 
animals are less sensitive to sounds at the outer edge of their 
generalized hearing range and most sensitive to sounds of frequencies 
within a smaller range somewhere in the middle of their functional 
hearing range).

           Table 3--Marine Mammal Hearing Groups (NMFS, 2016)
------------------------------------------------------------------------
                                            Generalized  hearing range 1
               Hearing group
------------------------------------------------------------------------
Low-frequency (LF) cetaceans (baleen        7 Hz to 35 kHz.
 whales).
Mid-frequency (MF) cetaceans (dolphins,     150 Hz to 160 kHz.
 toothed whales, beaked whales, bottlenose
 whales).
High-frequency (HF) cetaceans (true         275 Hz to 160 kHz.
 porpoises, Kogia, river dolphins,
 cephalorhynchid, Lagenorhynchus cruciger
 & L. australis).
Phocid pinnipeds underwater (PW) (true      50 Hz to 86 kHz.
 seals).
Otariid pinnipeds underwater (OW) (sea      60 Hz to 39 kHz.
 lions and fur seals).
------------------------------------------------------------------------
\1\ Represents the generalized hearing range for the entire group as a
  composite (i.e., all species within the group), where individual
  species' hearing ranges are typically not as broad. Generalized
  hearing range chosen based on ~65 dB threshold from normalized
  composite audiogram, with the exception for lower limits for LF
  cetaceans (Southall et al. 2007) and PW pinniped (approximation).

    As mentioned previously, six marine mammal species (two cetacean 
and four pinniped species) are likely to be incidentally taken by the 
proposed SFOBB controlled pier implosions. Of the two cetacean species, 
one belongs to the MF cetacean (bottlenose dolphin) hearing group, and 
one to the HF cetacean hearing group (harbor porpoise). Two species of 
pinniped are phocid (Pacific harbor seal and northern elephant seal), 
and two species of pinniped are otariid (California sea lion and 
northern fur seal). A species' hearing group is a consideration when we 
analyze the effects of exposure to sound on marine mammals.

[[Page 26068]]

General Information on Potential Effects
    Explosives are impulsive sounds, which are characterized by short 
duration, abrupt onset, and rapid decay. The proposed CALTRANS SFOBB 
work using controlled charges (i.e., implosion events) could adversely 
affect marine mammal species and stocks by exposing them to elevated 
noise levels in the vicinity of the activity area. Based on the nature 
of the other activities associated with the dismantling of Piers E6 
through E18 of the original SFOBB East Span (mechanical dismantling) 
and measured sound levels from those activities during past monitoring 
associated with previous IHAs, NMFS does not expect activities other 
than implosion events to contribute to underwater noise levels such 
that take of marine mammals would potentially occur.
    Exposure to high intensity sound for a sufficient duration may 
result in behavioral reactions and 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).
    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 kilohertz (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 a permanent loss within a 
specific frequency range, but some recovery is possible.
    For cetaceans, 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).
    Based on the best available scientific data, NMFS' 2016 Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing includes acoustic thresholds related to PTS and TTS for 
impulsive sounds that are expressed as weighted, cumulative sound 
exposure levels (SELcum) and unweighted peak sound pressure 
levels (SPLPK), as presented in Table 4.

                                       Table 4--NMFS Take Thresholds for Marine Mammals From Underwater Implosions
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                         Level B harassment              Level A                Serious injury
                                                -----------------------------------    harassment    -----------------------------------
            Group                   Species                                        ------------------      Gastro-                          Mortality
                                                    Behavioral           TTS               PTS        intestinal tract        Lung
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-freq cetacean............  Bottlenose        165 dB SEL.....  170 dB SEL or     185 dB SEL or     237 dB SPL......  39.1M1/3 (1+[D/  91.4M1/3 (1+[D/
                                dolphin.                           224 dB SPLpk.     230 dB SPLpk.                       10.081])1/2 Pa-  10.081])1/2 Pa-
                                                                                                                         sec. where: M    sec. where: M
                                                                                                                         = mass of the    = mass of the
                                                                                                                         animals in kg.   animals in kg.
                                                                                                                         D = depth of     D = depth of
                                                                                                                         animal in m..    animal in m.
High-freq cetacean...........  Harbor porpoise.  135 dB SEL.....  140 dB SEL or     155 dB SEL or     ................  ...............  ...............
                                                                   196 dB SPLpk.     202 dB SPLpk.
Phocidae.....................  Harbor seal &     165 dB SEL.....  170 dB SEL or     185 dB SEL or     ................  ...............  ...............
                                northern                           212 dB SPLpk.     218 dB SPLpk.
                                elephant seal.
Otariidae....................  California sea    183 dB SEL.....  188 dB SEL or     203 dB SEL or     ................  ...............  ...............
                                lion & northern                    226 dBpk.         232 dB SPLpk.
                                fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Note: All dB values are referenced to 1 [micro]Pa. SPLpk = Peak sound pressure level; psi = pounds per square inch.

    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 occurs when other noises, such as those 
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

[[Page 26069]]

whose acoustical sensors or environment are being severely masked could 
also be impaired from maximizing their performance fitness in survival 
and reproduction.
    Masking occurs at the frequency band which the animals utilize. 
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 3 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' proposed SFOBB construction activities, noises from 
controlled blasting is not likely to contribute to the elevated ambient 
noise levels in the project area in such a way as to 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, and the sound associated with the controlled 
blasting activities would be very brief.
    Finally, exposure of marine mammals to certain sounds could lead to 
behavioral disturbance (Richardson et al., 1995), such as: Changing 
durations of surfacing and dives, number of blows per surfacing, or 
moving direction and/or speed; reduced/increased vocal activities; 
changing/cessation of certain behavioral activities (such as 
socializing or feeding); visible startle response or aggressive 
behavior (such as tail/fluke slapping or jaw clapping); avoidance of 
areas where noise sources are located; and/or flight responses (e.g., 
pinnipeds flushing into water from haulouts or rookeries).
    The 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). For impulse noises (such as the proposed controlled 
implosions associated with the dismantling of the original SFOBB 
spans), NMFS uses received levels of 165 dB SEL to predict the onset of 
behavioral harassment for mid-frequency cetaceans and phocid pinnipeds 
(bottlenose dolphins and harbor seals and northern elephant seals, 
respectively); 135 dB SEP for high-frequency cetaceans (harbor 
porpoises); and 183 dB SEL for otariid pinnipeds (California sea lions 
and northern fur seals).
    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 proposed controlled 
blasting of Piers E6 through E18 would have the potential to impact 
marine mammals in the vicinity of the activity. The majority of impacts 
would be startle behavioral responses and temporary behavioral 
modification of marine mammals. 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 (GI) 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).
    The above discussion concerning underwater explosions only pertains 
to open water detonations in a free field.

[[Page 26070]]

CALTRANS' demolition of Piers E6 through E18 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 compared to expected levels from open water 
detonations (Hempen et al., 2007; CALTRANS 2016). Therefore, with 
monitoring and mitigation measures discussed below, CALTRANS' 
controlled implosions of Piers E6 through E18 are not likely to have 
injury or mortality effects on marine mammals in the project vicinity. 
Instead, NMFS considers that CALTRANS' proposed controlled implosions 
in the San Francisco Bay are most likely to cause behavioral harassment 
and may cause TTS in a few individual of marine mammals, as discussed 
below.
    Changes in marine mammal behavior are expected to result from acute 
stress, or startle, responses. This expectation is based on the idea 
that some sort of physiological trigger must exist to change any 
behavior that is already being performed, and this may occur due to 
being startled by the implosion events. The exception to this 
expectation is the case of behavioral changes due to auditory masking 
(increasing call rates or volumes to counteract increased ambient 
noise). Masking is not likely since the CALTRANS' controlled implosion 
would only consist of five to six short, sequential detonations that 
last for approximately 3-4 seconds each.
    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 due to the addition of sound and activity associated 
with the dismantling activities.
    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 site. 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 miles (mi) (14 kilometers (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 and would not occur in biologically important 
areas, would not significantly affect biologically important 
activities, and are not expected to have significant environmental 
effects, as noted in the original FHWA 2001 FEIS for the SFOBB project, 
incorporated by reference into NMFS' 2003 EA and subsequent 
Supplemental EAs (2009 and 2015) for the issuance of IHAs for the SFOBB 
project.
    SPLs from pier implosions have the potential to injure or kill fish 
in the immediate area. During previous pier implosion and pile driving 
activities, CALTRANS reported mortality to prey species of marine 
mammals, including northern anchovies and Pacific herring (CALTRANS 
2016), averaging approximately 200 fish per implosion event (none of 
which were ESA-listed species and none of which are managed under a 
Fishery Management Plan). These few isolated fish mortality events are 
not anticipated to have a substantial effect on prey species 
populations or their availability as a food resource for marine 
mammals.
    Studies on explosives also suggest that larger fish are generally 
less susceptible to death or injury than small fish, and results of 
most studies are dependent upon specific biological, environmental, 
explosive, and data recording factors. For example, 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; and finally, open water pelagic fish, such as 
those expected to be in the project area, seem to be less affected than 
reef fishes.
    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' controlled implosion events will 
likely be insignificant to the population as a whole.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through an IHA, which will inform both NMFS' 
consideration of whether the number of takes is ``small'' and the 
negligible impact determination.
    Harassment is the only type of take expected to result from these 
activities. 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).
    Authorized takes would be by Level B harassment only, in the form 
of disruption of behavioral patterns and/or TTS for individual marine 
mammals resulting from exposure to noise from the controlled implosions 
of 13 piers of the original East Span of the SFOBB. Based on the nature 
of activity and past results from controlled implosions of Piers E3, 
E4, and E5, Level A harassment is neither anticipated nor proposed to 
be authorized. The death of a marine mammal is also a type of 
incidental take. However, as described previously, no mortality is 
anticipated or proposed to be authorized for this activity. Below we 
describe how the take is estimated.
    The distance to marine mammal threshold criteria for implosion 
activities, and corresponding zones of influence (ZOI) have been 
determined based on underwater sound and pressure measurements 
collected during previous activities in the SFOBB Project area. The 
numbers of marine mammals by stock that may be taken by each type of 
take were calculated based on distance to the marine mammal threshold 
criteria, duration of the activity, and the estimated density of each 
stock in the ZOI. NMFS worked with CALTRANS and adjusted those 
estimated numbers upwards based on past monitoring data and/or other 
sightings data in the San Francisco Bay area to come up with a maximum 
number of potential occurrences for the requested takes, given that the 
number of marine mammals in the area is highly variable.

[[Page 26071]]

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 marine mammal monitoring conducted intermittently 
from 2000 to 2016 during observations made during monitoring for the 
SFOBB construction and demolition activities. 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 251 days of monitoring from 2000 through 2016 (including 15 
days of baseline monitoring in 2003), 958 harbor seals, 80 California 
sea lions, and 9 harbor porpoises were observed within the waters of 
the SFOBB east span (CLATRANS, 2001, 2004, 2013, 2014, 2015, 2016, 
2017). Northern elephant seal density in the project area was 
calculated from stranding records of the Marine Mammal Center (MMC). 
Too few observations or strandings of northern fur seals have occurred 
to determine density estimates. However, take estimates for northern 
fur seals were made based on stranding data, which was provided by the 
MMC. Similarly, too few observations of bottlenose dolphins have 
occurred to determine density estimates. Observations of bottlenose 
dolphins are primarily west of Treasure Island and concentrated along 
the nearshore areas of San Francisco south to Redwood City. One 
individual has been observed near Alameda and is thought to have likely 
passed by the project area, but no other reports of bottlenose dolphins 
exist in the project area. Therefore, bottlenose dolphin takes are 
based on the possibility of a few individuals potentially passing by 
the project area. Table 5 provides the estimated in-water densities 
used for calculating take of marine mammals in the SFOBB project area.

  Table 5--Estimated In-Water Densities of Marine Mammals in the SFOBB
                              Project Area
------------------------------------------------------------------------
                                 Main season of       Density (animals/
           Species                 occurrence              km\2\)
------------------------------------------------------------------------
Pacific Harbor seal (2015-    Fall-Winter.........  4.1
 2016).
Northern elephant seal......  Late Spring-Early     0.03
                               Winter.
California sea lion.........  Late Summer-Fall      0.09
                               (post breeding
                               season).
Northern fur seal...........  Late Fall-Early       Insufficient data.
                               Spring.
Bottlenose dolphin..........  Year Round..........  Insufficient data.
Harbor porpoise.............  Year Round..........  0.21
------------------------------------------------------------------------
Notes: Pacific harbor seal, California sea lion, and harbor porpoise
  densities based on monitoring for the east span of SFOBB from 2000 to
  2016. Elephant seal densities estimated from sighting and stranding
  data from MMC; A second set of Pacific harbor seal densities were
  estimated based on increases of sightings recorded during 2015-2016
  monitoring; Insufficient sighting data exist to estimate bottlenose
  dolphin density. However, a single animal has been regularly observed
  near the SFOBB east span; Insufficient sighting data exist to estimate
  northern fur seal densities in the Bay. Approximately 2-4 strandings
  occur in the entire Bay per year (unlikely to occur in the SFOBB
  project area).

1. Pacific Harbor Seal Density Estimates
    Most data on harbor seal populations are collected while the seals 
are hauled out because they are much easier to count when they are out 
of the water. In-water density estimates rely on haul-out counts, the 
percentage of seals not on shore based on radio telemetry studies, and 
the size of the foraging range of the population. Harbor seal density 
in the water can vary greatly depending on weather conditions or the 
availability of prey. For example, during Pacific herring runs further 
north in the Bay in February 2014 (outside of the hydroacoustic zone 
for Piers E6 to E18), very few harbor seals were observed foraging near 
YBI or transiting through the project area for approximately two weeks. 
Sightings went from a high of 27 harbor seals in one day to no seals 
observed (CALTRANS 2014). In 2015 and 2016, the number of harbor seals 
sighted in the project area increased up to 41 seals per day (CALTRANS 
2015 and 2016).
    Calculated harbor seal density for the proposed project is a per 
day estimate of harbor seals in a 1 square kilometer (km\2\) during the 
fall/winter or spring/summer season. Harbor seal density was calculated 
from all observations during the SFOBB project monitoring from 2000 to 
2016, with a second set of density estimates for 2015-2016 to account 
for an increase in daily harbor seal observations during monitoring in 
the fall of these years. Although multiple density estimates were 
calculated for harbor seals, the highest density (4.1/km\2\) was used 
to calculate estimated take to be conservative.
2. California Sea Lion Density Estimates
    Within the SFOBB Project area, California sea lion density was 
calculated from all observations of animals in the water during SFOBB 
Project monitoring from 2000 to 2016. 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.
    Calculated California sea lion density was a per day estimate of 
sea lions in 1 km\2\ during the fall/winter or spring/summer season in 
Table 4. The highest density value (0.09/km\2\) was used to calculate 
estimated take in order to be conservative.
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 because the Bay is not a usual haul-
out area for elephant seals. 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). The density estimate of 0.03 animals/km\2\ was 
conservatively estimated for the entire San Francisco

[[Page 26072]]

Bay based on stranding data over the 10-year period from 2004-2014, and 
adjusting to account for the time period of the proposed SFOBB 
activities. However, to be conservative, the actual number of takes 
requested was not based on the calculated takes using the density 
estimate. Instead, take estimates were requested based on qualitative 
worst-case (and unlikely) estimates assuming six implosion events may 
occur and assuming presence of three northern elephant seals at half 
(three) of the implosion events.
4. Northern Fur Seal
    Too few observations or strandings of northern fur seals have 
occurred to determine densities. Juveniles of this species occasionally 
strand in San Francisco Bay, particularly during El Nino events. During 
the 2016 El Nino event, northern fur seal juveniles were observed and 
stranded inside San Francisco Bay more frequently but were still not 
considered common. The MMC reported rescuing more than 80 stranded 
northern fur seal pups in 2015 and 2016, but only two to four northern 
fur seal strandings occurred in the Bay. That number is likely to 
decrease because the El Nino and warm water blob that affected the 
species' food resources has dissipated. Requested take was based on 
qualitative worst-case (and unlikely) estimates assuming six implosion 
events may occur and assuming presence of three northern fur seals at 
half (three) of the implosion events.
5. Common Bottlenose Dolphin Density Estimates
    Too few observations of bottlenose dolphins have occurred to 
determine density. Observations of bottlenose dolphins primarily have 
occurred west of Treasure Island and were concentrated along the 
nearshore area of San Francisco south to Redwood City. One individual 
has been observed regularly near Alameda and likely passed by the 
project area, but no other reports of bottlenose dolphins exist in the 
project area (Perlman 2017). Requested take was based on qualitative 
worst-case (and unlikely) estimates assuming six implosion events may 
occur and assuming presence of three bottlenose dolphins at half 
(three) of the implosion events.
6. Harbor Porpoise Density Estimates
    Harbor porpoise density was calculated from all observations during 
SFOBB Project monitoring, from 2000 to 2016. 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 16 years of monitoring in the SFOBB Project area, only 9 
harbor porpoises were observed, and all occurred between 2006 and 2015 
(including two in 2014 and 5 in 2015). Based on this data, a density 
estimate of 0.21 animals/km\2\ was used to calculate estimated take.

Distance Calculations for Marine Mammal Threshold Criteria and 
Corresponding Zones of Influence (ZOI)

    Utilizing the marine mammal threshold criteria from NMFS' 2016 
Technical Guidance for Assessing the Effects of Anthropogenic Sound on 
Marine Mammal Hearing (NMFS 2016), presented in Table 4, distances to 
these threshold criteria were calculated using the results from 
previous hydroacoustic monitoring associated with the implosions of 
Piers E3, E4, and E5. In addition, the criteria for lung injury and 
mortality to marine mammals is dependent on the mass of the animal and 
depth of the animal in the water column. Animals that are smaller in 
mass are more susceptible to injury from impulse pressures from 
blasting, so the mass of juveniles (6 to 16 months old) from each 
species was used in the calculations because these would be the 
smallest animals potentially exposed. As Piers E6 through E18 are in 
water that ranges from 10 to 40 ft (3 to 12 m), and due to the fact 
that the species that may be present in the project area surface 
frequently, and average depth of 20 ft (6 m) was used in the threshold 
calculations for lung injury and mortality.
    Distances to marine mammal threshold criteria were calculated for 
each of the potential pier implosion scenarios:
     Implosion of Pier E6.
     Implosion of two 504-ft span piers in one implosion event.
     Implosion of two 288-ft span piers in one implosion event.
     Implosion of three 288-ft span piers in one implosion 
event.
     Implosion of four 288-ft span piers in one implosion 
event.
    Methods used to calculate distances to threshold criteria for the 
implosion of multiple piers are presented in detail in Appendix C of 
CALTRANS' application. Table 6 presents the distances calculated to 
each threshold for each of the anticipated pier implosion scenarios.

                                       Table 6--Threshold Distances (feet) Calculated for Each Implosion Scenario
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                   Level B harassment       Level A        Serious injury
                                                                               --------------------------  harassment ------------------------
                    Group                                  Species                                       -------------                         Mortality
                                                                                 Behavioral    TTS (pk/     PTS (pk/    GI tract  Slight lung
                                                                                               SELcum)      SELcum)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Implosion of Pier E6
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-freq cetacean............................  Bottlenose dolphin.............        1,330      180/881       98/256         48           48        <40
High-freq cetacean...........................  Harbor porpoise................       12,567  3,127/8,358  1,697/2,459         48           48        <40
Phocidae.....................................  Harbor seal & northern elephant        2,220    613/1,484      332/443         48           48        <40
                                                seal.
Otariidae....................................  California sea lion & northern           554      147/367       80/106         48           48        <40
                                                fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Implosion of Two 504-ft Span Piers
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-freq cetacean............................  Bottlenose dolphin.............        1,055      166/685       90/190         44          <40        <40
High-freq cetacean...........................  Harbor porpoise................       10,300  2,882/6,800  1,564/1,966         44          <40        <40
Phocidae.....................................  Harbor seal & northern elephant        1,790    565/1,186      306/333         44          <40        <40
                                                seal.
Otariidae....................................  California sea lion & northern           421      136/274        74/78         44          <40        <40
                                                fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 26073]]

 
                                                           Implosion of Two 288-ft Span Piers
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-freq cetacean............................  Bottlenose dolphin.............          798      166/517       90/126         44          <40        <40
High-freq cetacean...........................  Harbor porpoise................        7,700  2,882/5,140  1,564/1,493         44          <40        <40
Phocidae.....................................  Harbor seal & northern elephant        1,359      565/900      306/232         44          <40        <40
                                                seal.
Otariidae....................................  California sea lion & northern           304      136/185        74/52         44          <40        <40
                                                fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                          Implosion of Three 504-ft Span Piers
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-freq cetacean............................  Bottlenose dolphin.............          920      166/588       90/132         44          <40        <40
High-freq cetacean...........................  Harbor porpoise................        9,403  2,882/5,900  1,564/1,722         44          <40        <40
Phocidae.....................................  Harbor seal & northern elephant        1,580    565/1,045      306/258         44          <40        <40
                                                seal.
Otariidae....................................  California sea lion & northern           339      136/201        74/52         44          <40        <40
                                                fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                           Implosion of Four 504-ft Span Piers
--------------------------------------------------------------------------------------------------------------------------------------------------------
Mid-freq cetacean............................  Bottlenose dolphin.............          920      166/558       90/132         44          <40        <40
High-freq cetacean...........................  Harbor porpoise................        9,935  2,882/6,590  1,564/1,917         44          <40        <40
Phocidae.....................................  Harbor seal & northern elephant        1,730    565/1,135      306/264         44          <40        <40
                                                seal.
Otariidae....................................  California sea lion & northern           349      136/204        74/52         44          <40        <40
                                                fur seal.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Estimated Takes of Marine Mammals

    The number of marine mammals by stock that may be taken by 
implosion of Piers E6 through E18 were calculated based on distances to 
the marine mammal threshold criteria, duration of the activity, and the 
estimated density of each species in the ZOI (for species with 
insufficient data to calculate densities, estimated number of takes 
were based on potential for occurrence as described above). For each 
pier implosion scenario, the total area of the criteria zone was 
calculated and multiplied by the density of each species. Combining 
multiple piers in a single implosion event results in fewer implosion 
events and, therefore, fewer marine mammals that would potentially be 
taken. However, take estimates were calculated based on a worst-case 
scenario of a total of six implosion events.. Based on calculated sound 
pressure levels and the implementation of avoidance and minimization 
measures discussed below, no injury (Level A harassment) or mortality 
is anticipated to occur as a result of the implosion activities and 
NMFS is not authorizing any Level A takes for this activity. For more 
detailed information on the number of takes calculated for each 
implosion scenario, see Table 19 of the CALTRANS IHA application. For 
spreadsheets showing the calculations that were performed to estimate 
marine mammal exposures for each pier implosion scenario, see Appendix 
D of the IHA application. Table 7 provides a summary of the estimated 
exposure of marine mammals based on calculations using density 
estimates or past monitoring efforts in cases where density estimates 
were not able to be calculated (northern fur seal and bottlenose 
dolphin).

  Table 7--Estimated Combined Exposures of Marine Mammals to the Implosions of Piers E6 Through E18 for Levels A and B and Mortality Threshold Criteria
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                   Level B exposures for all implosions                      Level A exposures \1\
             Species             ----------------------------------------------------------------------------------------------------    Mortality \1\
                                       Behavior               TTS                 PTS              GI injury      Slight lung injury
--------------------------------------------------------------------------------------------------------------------------------------------------------
Harbor seal.....................  22................  16................  0.................  0.................  0.................  0
California sea lion.............  0.................  0.................  0.................  0.................  0.................  0
Northern elephant seal..........  0.................  0.................  0.................  0.................  0.................  0
Northern fur seal...............  \2\ NA (0)........  \2\ NA (0)........  \2\ NA (0)........  \2\ NA (0)........  \2\ NA (0)........  \2\ NA (0)
Bottlenose dolphin..............  \2\ NA (0)........  \2\ NA (0)........  \2\ NA (0)........  \2\ NA (0)........  \2\ NA (0)........  \2\ NA (0)
Harbor porpoise.................  0.................  0.................  0.................  0.................  0.................  0
                                 -----------------------------------------------------------------------------------------------------------------------
    TOTAL.......................  22................  16................  0.................  0.................  0.................  0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ No implosions would occur if any marine mammal is within the Level A or mortality threshold criteria zones.
\2\ No density estimates were calculated, so calculations of take were not completed; However, no takes are estimated in this table based on the fact
  that none of these species have been observed since monitoring efforts for the SFOBB project began in 2000.


[[Page 26074]]

    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 based on past 
monitoring data and/or other sightings data in the San Francisco Bay 
area to come up with a maximum number of potential occurrences for the 
requested takes. These adjustments were based on likely group sizes of 
these animals and were developed quantitatively to account for 
variability in animal occurrence and activity.
    A summary of the requested number of takes by implosion of Piers E6 
through E18 is provided in Table 8.

             Table 8--Summary of Requested Takes of Marine Mammals for the Pier E4 and E5 Implosions
----------------------------------------------------------------------------------------------------------------
                                                      Level B                          Stock       Percent take
                     Species                        behavioral      Level B TTS      abundance     of population
----------------------------------------------------------------------------------------------------------------
Pacific harbor seal.............................              66              48          30,968            0.37
California sea lion.............................              18              12         296,750            0.01
Northern elephant seal..........................               6               3         179,000            0.01
Northern fur seal...............................               6               3          12,844            0.21
Harbor porpoise.................................              18               9           9,886            0.09
Bottlenose dolphin..............................               6               3             323             2.8
                                                 ---------------------------------------------------------------
    Total.......................................             120              78  ..............  ..............
----------------------------------------------------------------------------------------------------------------

Proposed Mitigation

    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 (the latter is not 
applicable for this action). NMFS' regulations require applicants for 
incidental take authorizations to include information about the 
availability and feasibility (economic and technological) of equipment, 
methods, and manner of conducting such activity or other means of 
effecting the least practicable adverse impact upon the affected 
species or stocks and their habitat (50 CFR 216.104(a)(11)).
    In evaluating how mitigation may or may not be appropriate to 
ensure the least practicable adverse impact on species or stocks and 
their habitat, as well as subsistence uses where applicable, we 
carefully weigh two primary factors: (1) The manner in which, and the 
degree to which, the successful implementation of the measure(s) is 
expected to reduce impacts to marine mammals, marine mammal species or 
stocks, and their habitat, which considers the nature of the potential 
adverse impact being mitigated (likelihood, scope, range), as well as 
the likelihood that the measure will be effective if implemented; and 
(2) the practicability of the measures for applicant implementation, 
which may consider such things as cost and impact on operations.

Proposed Mitigation Measures for Confined Implosion

    For CALTRANS's proposed controlled implosions of Piers E6 through 
E18, CALTRANS will utilize the mitigation measures discussed below to 
minimize the potential impacts to marine mammals in the project 
vicinity, which were developed and successfully employed for previous 
controlled implosions of other piers of the original East Span of the 
SFOBB. The primary purposes of these mitigation measures are to 
minimize impacts by reducing sound levels from the activities and to 
monitor for marine mammals within designated exclusion zones and zones 
of influence (ZOI). Specific proposed mitigation measures are:

Time Restriction

    Implosion of Piers E6 through E18 would only be conducted during 
daylight hours, with enough time for pre and post implosion monitoring 
during daylight hours. Implosion events would also only be conducted 
during periods with good visibility when the largest exclusion zone can 
be visually monitored. In addition, to minimize impacts on biological 
resources, implosion events would be conducted at slack tides between 
September and November.

Installation of Blast Attenuation System (BAS)

    Prior to the demolition of Piers E6 through E18, CALTRANS would 
install a Blast Attenuation System (BAS) as described above to reduce 
the noise and shockwave from the implosion.

Establishment of Level A Exclusion Zone

    CALTRANS will establish marine mammal exclusion zones (MMEZ) for 
both the mortality and Level A harassment zone (including PTS, GI track 
injury, and slight lung injury) using the criteria threshold that 
extends out the furthest distance (refer to Table 6). As an additional 
conservative measure to ensure that no marine mammals are taken by 
Level A harassment, the field-implemented MMEZ will be 20 percent 
larger than the calculated distances to threshold criteria in Table 6.
    The isopleths for PTS for phocids (harbor seal and elephant seal) 
cover the entire area for both Level A harassment and mortality for all 
pinnipeds (including California sea lions and northern fur seals), as 
well as bottlenose dolphins. Therefore, the pinniped and dolphin 
exclusion zone will be established at the radial distance to the phocid 
PTS Level A harassment threshold plus an additional 20 percent 
conservative factor. The harbor porpoise exclusion zone will be 
established at the radial distance to the high-frequency cetacean PTS 
Level A harassment threshold plus an additional 20 percent conservative 
factor (see Table 23 and Figures 12-14 and 17-21 of the IHA 
application). These MMEZs will be monitored by marine mammal observers 
(MMOs), and if any marine mammals are observed within the MMEZs, the 
implosion will be delayed until the animal leaves the area or at least 
15 minutes have passed since the last observation of pinnipeds and 
small cetaceans and at least 30 minutes have passed since the last 
observation of bottlenose dolphins.

[[Page 26075]]

Establishment of Level B Behavioral Harassment and Temporary Hearing 
Threshold Shift (TTS) Monitoring Zones

    Marine mammal monitoring zones will be established for both 
behavioral response and TTS (Level B harassment). Hydroacoustic 
monitoring results from the implosions of Piers E3, E4, and E5 were 
used to calculate distances to these thresholds for the implosions of 
Piers E6 through E18 (see Chapter 6 and Tables 9 to 18 of the IHA 
application). As a conservative measure, the field-implemented 
behavioral response and TTS monitoring zones will be 20 percent larger 
than the calculated distances to threshold criteria shown in Tables 9 
to 18 of the IHA application.
    The isopleths for Level B harassment to phocids (harbor seals and 
elephant seals) for all pier implosion scenarios cover the entire area 
for Level B harassment to all pinnipeds including otariids (California 
sea lions and fur seals) as well as bottlenose dolphins. Therefore, the 
pinniped and dolphin Level B harassment monitoring zones for each pier 
implosion scenario will be established at the radial distance to the 
phocid Level B harassment threshold plus an additional 20 percent 
conservative factor (see Tables 24 and 25 and Figures 12-16 of the IHA 
application).

Communication

    All Marine Mammal Observers (MMOs) will be equipped with mobile 
phones and a VHF radio as a backup. One person will be designated as 
the Lead MMO and will be in constant contact with the Resident Engineer 
on site and the blasting crew. The Lead MMO will coordinate marine 
mammal sightings with the other MMOs. MMOs will contact the other MMOs 
when a sighting is made within the exclusion zone or near the exclusion 
zone so that the MMOOs within overlapping areas of responsibility can 
continue to track the animal and the Lead MMO is aware of the animal. 
If an animal has entered the exclusion zone or is near it within 30 
minutes of blasting, the Lead MMO will notify the Resident Engineer and 
blasting crew. The Lead MMO will keep them informed of the disposition 
of the animal.

Mitigation Conclusions

    NMFS has carefully evaluated the applicant's proposed mitigation 
measures and considered a range of other measures in the context of 
ensuring that NMFS prescribes the means of effecting the least 
practicable 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 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 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 activities expected to result in the take of marine mammals 
(this goal may contribute to a, 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 measures, as 
well as other measures considered by NMFS, NMFS has preliminarily 
determined that the proposed mitigation measures provide the means of 
effecting the least practicable impact on marine mammals species or 
stocks and their habitat, paying particular attention to rookeries, 
mating grounds, and areas of similar significance.

Proposed Monitoring and Reporting

    In order to issue an IHA for an activity, section 101(a)(5)(D) of 
the MMPA states that NMFS must set forth, ``requirements pertaining to 
the monitoring and reporting of such taking.'' The MMPA implementing 
regulations at 50 CFR 216.104 (a)(13) indicate that requests for 
Incidental Take Authorizations (ITA) 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. Effective reporting is critical to 
both compliance as well as ensuring that the most value is obtained 
from the required monitoring. CALTRANS has proposed marine mammal 
monitoring measures as part of the IHA application found at http://www.nmfs.noaa.gov/pr/permits/incidental.htm. The plan may be modified 
or supplemented based on comments or new information received from the 
public during the public comment period.
    Monitoring measures prescribed by NMFS should accomplish one or 
more of the following general goals:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, absence, distribution, 
density).
     Nature, scope, or context of likely marine mammal exposure 
to potential stressors/impacts (individual or cumulative, acute or 
chronic), through better understanding of: (1) Action or environment 
(e.g., source characterization, propagation, ambient noise); (2) 
affected species (e.g., life history, dive patterns); (3) co-occurrence 
of marine mammal species with the action; or (4) biological or 
behavioral context of exposure (e.g., age, calving, or feeding areas).
     Individual marine mammal responses (behavioral or 
physiological) to acoustic stressors (acute, chronic, or cumulative), 
other stressors, or cumulative impacts from multiple stressors.
     How anticipated responses to stressors impact either: (1) 
Long-term fitness and survival of individual marine animals; or (2) 
populations, species, or stocks.
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important

[[Page 26076]]

physical components of marine mammal habitat).
     Mitigation and monitoring effectiveness.

Proposed Monitoring Measures

    As most elements of marine mammal monitoring plans for pile driving 
activities are similar to what would be required for underwater 
implosions, monitoring for impacts to marine mammals from the implosion 
activities for Piers E3, E4, and E5 were based on the SFOBB pile 
driving monitoring protocol. Monitoring for the implosion events for 
Piers E6 through E18 will also be based on the SFOBB pile driving 
monitoring protocol and past implosion activities for Piers E3, E4, and 
E5. These monitoring plans would include monitoring an exclusion zone 
and ZOIs for TTS and behavioral harassment described above as well as 
the following:
(1) Marine Mammal Observers (MMOs)
    A minimum of 10 MMOs would be required during the controlled 
implosions of Piers E6 through E18 so that the MMEZ, Level B Harassment 
TTS and Behavioral ZOIs, and surrounding area can be monitored. Up to 
15 MMOs will be required for implosion events involving multiple piers 
in order to monitor the full extent of these areas. One MMO would be 
designated as the Lead MMO and would receive updates from other MMOs on 
the presence or absence of marine mammals within the MMEZ and would 
notify the Environmental Compliance Manager of a cleared exclusion zone 
to the implosion(s).
(2) Monitoring Protocol
    Implosions of Piers E6 through E18 will be conducted only during 
daylight hours and with enough time for pre and post-implosion 
monitoring during daylight hours, and with good visibility (i.e., clear 
skies and no high winds). This work will be completed so that MMOs will 
be able to detect marine mammals within the exclusion zones and beyond. 
The Lead MMO will be in contact with other MMOs and if any marine 
mammals enter an exclusion zone within 30 minutes of blasting, the Lead 
MMO will notify the Environmental Compliance Manager that the implosion 
may need to be delayed. The Lead MMO will keep the Environmental 
Compliance Manager informed about the disposition of the animal. If the 
animal remains in the MMEZ, 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 for pinnipeds and small cetacean 
(harbor porpoise), and 30 minutes for bottlenose dolphin. After the 
implosion has occurred, the MMOs will continue to monitor the area for 
at least 60 minutes.
(3) Data Collection
    Each MMO 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 being imploded (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 E6 
through E18 is very unlikely, boat or shore surveys will be conducted 
daily for 3 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 pier 
implosions.

Proposed 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 (if issued), 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

    Stranding plans for the pier implosions of Piers E3, E4, and E5 
were 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 E6 through 
E18. 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 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 3 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.
Negligible Impact Analysis and Determinations
    NMFS has defined negligible impact 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 (50 CFR 216.103). A 
negligible impact finding is based on the lack of likely adverse 
effects on annual rates of

[[Page 26077]]

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 (e.g., critical 
reproductive time or location, migration, etc.), as well as effects on 
habitat, and the likely effectiveness of the mitigation. We also assess 
the number, intensity, and context of estimated takes by evaluating 
this information relative to population status. Consistent with the 
1989 preamble for NMFS' implementing regulations (54 FR 40338; 
September, 29, 1989), the impacts from other past and ongoing 
anthropogenic activities are incorporated into this analysis via their 
impacts on the environmental baseline (e.g., as reflected in the 
regulatory status of the species, population size and growth rate where 
known, ongoing sources of human-caused mortality, or ambient noise 
levels).
    To avoid repetition, this introductory discussion of our analyses 
applies to all the species and stocks listed in Table 8, given that the 
anticipated effects of CALTRANS' SFOBB construction activities 
involving controlled implosions for Piers E6 through E18 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 activity associated with the controlled implosions to 
demolish Piers E6 through E18, and none are proposed to be authorized. 
The relatively low marine mammal density and small Level A exclusion 
zones 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 proposed 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 responses and 
TTS). Due to implementation of mitigation measures and proven success 
in implementation of these measures as evidenced during previous SFOBB 
activities, more significant acute stress responses, serious injury or 
mortality, and more significant behavioral responses are not 
anticipated as a result of the proposed activities. Marine mammals 
(Pacific harbor seal, northern elephant seal, California sea lion, 
northern fur seal, 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 the implosion 
noise. A few marine mammals could experience TTS if they occur within 
the Level B TTS ZOI. 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 lead to PTS. Finally, there is no critical habitat 
or other biologically important areas in the vicinity of CALTRANS' 
proposed 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 ``Potential Effects of the Specified Activity on Marine Mammals and 
their 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 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 proposed monitoring and 
mitigation measures, NMFS preliminarily finds that the total marine 
mammal take from CALTRANS's SFOBB demolition via controlled implosions 
of Piers E6 through E18 will have a negligible impact on the affected 
marine mammal species or stocks.

Small Numbers

    Table 8 presents the numbers of marine mammals that could be taken 
by Level B harassment incidental to CALTRAN's activities. Our analysis 
shows that less than 2.8 percent of the affected stocks could be taken 
by behavioral harassment and TTS (see Table 8 in this document). 
Therefore, the numbers of marine mammals estimated to be taken are 
small relative to total populations of the affected species or stocks. 
In addition, the mitigation and monitoring measures (described 
previously in this document) prescribed in the proposed 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 preliminarily 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. 
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 (ESA)

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

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 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

[[Page 26078]]

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 proposed 
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).

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to CALTRANS for conducting SFOBB activities involving 
demolition via controlled implosion of Piers E6 through E18, provided 
the previously mentioned mitigation, monitoring, and reporting 
requirements are incorporated. The proposed IHA language is provided 
next.
    1. This Authorization is valid from September 1, 2017, through 
August 31, 2018.
    2. This Authorization is valid only for activities associated with 
the SFOBB demolition activities in San Francisco Bay.
    3. (a) The species authorized for incidental harassment takings, 
Level B harassment only, are: Pacific harbor seal (Phoca vitulina 
richardii), California sea lion (Zalophus californianus), northern 
elephant seal (Mirounga angustirostris), northern fur seal (Callorhinus 
ursinus), harbor porpoise (Phocoena phocoena), and bottlenose dolphin 
(Tursiops truncatus).
    (b) The authorization for taking by harassment is limited to the 
dismantling of Piers E6 through E18 via controlled implosion.
    (c) The taking of any marine mammal in a manner prohibited under 
this Authorization must be reported within 24 hours of the taking to 
the West Coast Administrator of the National Marine Fisheries Service 
(NMFS) at 206-526-6150, and the Chief of the Permits and Conservation 
Division, Office of Protected Resources, NMFS, at (301) 427-8401, or 
her designee (301-427-8418).
    4. The holder of this Authorization must notify the Chief of the 
Permits and Conservation Division, Office of Protected Resources, at 
least 48 hours prior to the start of activities identified in 3(b) 
(unless constrained by the date of issuance of this Authorization in 
which case notification shall be made as soon as possible).
5. Prohibitions
    (a) The taking, by incidental harassment only, is limited to the 
species listed under condition 3(a) above and by the numbers listed in 
Table 8 of this notice. The taking by Level A harassment, injury, or 
death of these species or the taking by harassment, injury, or death of 
any other species of marine mammal is prohibited and may result in the 
modification, suspension, or revocation of this Authorization.
    (b) The taking of any marine mammal is prohibited whenever the 
required marine mammal observers (MMOs), required by condition 7(a), 
are not present in conformance with condition 7(a) of this 
Authorization.
6. Mitigation
(a) Time Restriction
    Controlled implosion of Piers E6 through E18 shall only be 
conducted during daylight hours on slack tides between September and 
November and with enough time for pre- and post-activity monitoring 
during daylight hours. Further, controlled implosion shall only be 
conducted during periods of good visibility when the largest exclusion 
zone can be visually monitored.
    (b) For controlled implosion of Piers E6 through E18, CALTRANS will 
install a Blast Attenuation System (BAS) prior to demolition to reduce 
the noise and shockwave from the implosion.
    (c) For controlled implosion of Piers E6 though E18 and associated 
test blasting, CALTRANS shall establish exclusions zones and zones of 
influence (ZOIs) that are appropriate to specific marine mammal 
functional hearing group (Tables 1-10, Attachment 1; see Tables 9-18 of 
the application) .
    (d) Exclusion Zone Monitoring for Mitigation Measures.
    (i) NMFS-approved MMOs shall survey the exclusion zone for 30 
minutes prior to the start of controlled implosion activities to ensure 
that no marine mammals are seen within the zones
    (ii) If marine mammals are found within the exclusion zones, 
controlled implosion of the pier(s) shall be delayed until they move 
out of the area. If a marine mammal is seen above water and then dives 
below, the contractor shall wait 15 minutes for pinnipeds and small 
cetaceans (harbor porpoise) and 30 minutes for bottlenose dolphins 
prior to initiating implosion activities. If no marine mammals are seen 
by the observer in that time it would be assumed that the animal has 
moved beyond the exclusion zone.
(e) Communication
    For controlled implosion, the Lead MMO shall be in constant contact 
with the Resident Engineer on site and the blasting crew to ensure that 
no marine mammal is within the exclusion zone before the controlled 
implosion.
    7. Monitoring:
    (a) Marine Mammal Observers.
    (i) CALTRANS shall employ NMFS-approved MMOs to conduct marine 
mammal monitoring for its SFOBB controlled pier implosion.
    (ii) Marine mammal monitoring shall begin at least 30 minutes prior 
to the start of the activities, shall occur through the entire 
activities, and shall continue for 60 minutes after the implosion 
events.
    (iii) Observations shall be made using high-quality binoculars 
(e.g., Zeiss, 10 x 42 power). MMOs shall 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.
    (iv) For controlled implosion of Piers E6 through E18:
    (A) A minimum of 10 MMOs shall be required during controlled 
implosion so that the exclusion zone, Level B Harassment TTS and 
Behavioral ZOIs, and surrounding area can be monitored. Up to 15 MMOs 
will be required for implosion events involving multiple piers.
    (B) MMOs shall be positioned near the edge of each of the threshold 
criteria zones and shall utilize boats, barges, and bridge piers and 
roadway.
    (C) Boat or shore surveys shall be conducted immediately after the 
event and daily for the three days following the event to determine if 
there are any injured or stranded marine mammals in the area.
    (D) Monitoring Data Collection:
    For each marine mammal sighting, the following shall be recorded, 
if possible:
     Species.
     Number of animals (with or without pup/calf).
     Age class (pup/calf, juvenile, adult).
     Identifying marks or color (scars, red pelage, damaged 
dorsal fin, etc.).
     Position relative to pier implosion (distance and 
direction).
     Movement (direction and relative speed).
     Behavior (logging [resting at the surface], swimming, 
spyhopping [raising above the water surface to view the area], 
foraging, etc.)

[[Page 26079]]

     Duration of sighting or times of multiple sightings of the 
same individual
    8. Reporting:
    (a) CALTRANS shall submit a draft monitoring report within 90 days 
after completion of the dismantling work or the expiration of the IHA 
(if issued), whichever comes earlier. This report would detail the 
monitoring protocol, summarize the data recorded during monitoring, and 
estimate the number of marine mammals that may have been harassed.
    (b) NMFS will have an opportunity to provide comments within 30 
days after receiving the draft report. If NMFS has comments, CALTRANS 
shall address the comments and submit a final report to NMFS within 30 
days.
    (c) If NMFS does not provide comments within 30 days after 
receiving the report, the draft report is considered to be final.
    (d) In the unanticipated event that the dismantling activities 
clearly cause the take of a marine mammal in a manner prohibited by 
this Authorization (if issued), such as an injury, serious injury, or 
mortality, CALTRANS shall immediately cease all operations and 
immediately report the incident to the Chief, Permits and Conservation 
Division, Office of Protected Resources, NMFS, and the West Coast 
Regional Stranding Coordinators. The report must include the following 
information:
    (i) Time, date, and location (latitude/longitude) of the incident;
    (ii) Description of the incident;
    (iii) Status of all sound source use in the 24 hours preceding the 
incident;
    (iv) Environmental conditions (e.g., wind speed and direction, sea 
state, cloud cover, visibility, and water depth);
    (v) Description of marine mammal observations in the 24 hours 
preceding the incident;
    (vi) Species identification or description of the animal(s) 
involved;
    (vii) The fate of the animal(s); and
    (viii) Photographs or video footage of the animal (if equipment is 
available).
    Activities shall not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS shall work with CALTRANS to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. CALTRANS may not resume 
their activities until notified by NMFS via letter, email, or 
telephone.
    (e) In the event that CALTRANS discovers an injured or dead marine 
mammal, and the lead MMO determines that the cause of the injury or 
death is unknown and the death is relatively recent (i.e., in less than 
a moderate state of decomposition as described in the next paragraph), 
CALTRANS will immediately report the incident to the Chief, Permits and 
Conservation Division, Office of Protected Resources, NMFS, and the 
West Coast Regional Stranding Coordinators. The report must include the 
same information identified above. Activities may continue while NMFS 
reviews the circumstances of the incident. NMFS will work with CALTRANS 
to determine whether modifications in the activities are appropriate.
    (f) In the event that CALTRANS discovers an injured or dead marine 
mammal, and the lead MMO determines that the injury or death is not 
associated with or related to the activities authorized in the IHA 
(e.g., previously wounded animal, carcass with moderate to advanced 
decomposition, or scavenger damage), CALTRANS shall report the incident 
to the Chief, Permits and Conservation Division, Office of Protected 
Resources, NMFS, and the West Coast Regional Stranding Coordinators, 
within 24 hours of the discovery. CALTRANS shall provide photographs or 
video footage (if available) or other documentation of the stranded 
animal sighting to NMFS and the Marine Mammal Stranding Network. 
CALTRANS can continue its operations under such a case.
    9. Marine Mammal Stranding Plan:
    A marine mammal stranding plan shall be prepared in cooperation 
with the local NMFS-designated marine mammal stranding, rescue, and 
rehabilitation center. Elements of that plan would include the 
following:
    (a) The stranding crew shall prepare treatment areas at the NMFS-
designated facility for cetaceans or pinnipeds that may be injured from 
the implosion. Preparation shall 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. 
Equipment to conduct auditory brainstem response hearing testing would 
be available to determine if any inner ear threshold shifts (TTS or 
PTS) have occurred.
    (b) A stranding crew and a veterinarian shall be on call near the 
implosion event sites at the time of the implosion to quickly recover 
any injured marine mammals, provide emergency veterinary care, 
stabilize the animal's condition, and transport individuals to the 
NMFS-designated facility. If an injured or dead animal is found, NMFS 
(both the regional office and headquarters) shall be notified 
immediately even if the animal appears to be sick or injured from other 
than blasting.
    (c) Post-implosion surveys shall be conducted immediately after the 
event and over the following three days to determine if there are any 
injured or dead marine mammals in the area.
    (d) Any veterinarian procedures, euthanasia, rehabilitation 
decisions and time of release or disposition of the animal shall be at 
the discretion of the NMFS-designated facility staff and the 
veterinarians treating the animals. Any necropsies to determine if the 
injuries or death of an animal was the result of the blast or other 
anthropogenic or natural causes will be conducted at the NMFS-
designated facility by the stranding crew and veterinarians. The 
results shall be communicated to both CALTRANS and to NMFS as soon as 
possible with a written report within a month.
    10. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein or if the 
authorized taking is having more than a negligible impact on the 
species or stock of affected marine mammals, or if there is an 
unmitigable adverse impact on the availability of such species or 
stocks for subsistence uses.
    11. A copy of this Authorization must be in the possession of each 
contractor who performs the controlled implosion work for Piers E6 
through E18 and associated Test Blasts.

    Dated: June 1, 2017.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2017-11646 Filed 6-5-17; 8:45 am]
BILLING CODE 3510-22-P