[Federal Register Volume 83, Number 83 (Monday, April 30, 2018)]
[Notices]
[Pages 18802-18827]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-09033]



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DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

RIN 0648-XG067


Takes of Marine Mammals Incidental to Specified Activities; 
Taking Marine Mammals Incidental to the Chevron Richmond Refinery Long 
Wharf Maintenance and Efficiency Project in San Francisco Bay, 
California

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

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

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SUMMARY: NMFS has received a request from Chevron for authorization to 
take marine mammals incidental to incidental to pile driving and 
removal associated with the Long Wharf Maintenance and Efficiency 
Project (WMEP) in San Francisco Bay, 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. NMFS 
will consider public comments prior to making any final decision on the 
issuance of the requested MMPA authorizations and agency responses will 
be summarized in the final notice of our decision.

DATES: Comments and information must be received no later than May 30, 
2018.

ADDRESSES: Comments should be addressed to Jolie Harrison, Chief, 
Permits and Conservation Division, Office of Protected Resources, 
National Marine Fisheries Service. Physical comments should be sent to 
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 https://www.fisheries.noaa.gov/node/23111 without change. All personal 
identifying information (e.g., name, address) 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: Rob Pauline, Office of Protected 
Resources, NMFS, (301) 427-8401. Electronic copies of the application 
and supporting documents, as well as a list of the references cited in 
this document, may be obtained online 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 (as delegated to NMFS) 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 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).

National Environmental Policy Act

    To comply with the National Environmental Policy Act of 1969 (NEPA; 
42 U.S.C. 4321 et seq.) and NOAA Administrative Order (NAO) 216-6A, 
NMFS must review our proposed action (i.e., the issuance of an 
incidental harassment authorization) with respect to potential impacts 
on the human environment.
    This action is consistent with categories of activities identified 
in Categorical Exclusion B4 (incidental harassment authorizations with 
no anticipated serious injury or mortality) of the Companion Manual for 
NOAA Administrative Order 216-6A, which do not individually or 
cumulatively have the potential for significant impacts on the quality 
of the human environment and for which we have not identified any 
extraordinary circumstances that would preclude this categorical 
exclusion. Accordingly, NMFS has preliminarily determined that the 
issuance of the proposed IHA qualifies to be categorically excluded 
from further NEPA review.
    We will review all comments submitted in response to this notice 
prior to concluding our NEPA process or making a final decision on the 
IHA request.

Summary of Request

    On February 1, 2018, NMFS received a request from Chevron for an 
IHA to take marine mammals incidental to pile driving and pile removal 
associated with the WMEP in San Francisco Bay, California. Chevron's 
request is for take of seven species by Level B and Level A harassment. 
Neither Chevron nor NMFS expects serious injury or mortality to result 
from this activity and, therefore, an IHA is appropriate.
    NMFS previously issued an IHA to Chevron for similar work (82 FR 
27240; June 17, 2017). However, the construction schedule and scope was 
revised and no work was conducted under that IHA. The revised schedule 
includes the use of piles that were not planned for use under the 
existing IHA. Therefore, a new IHA is required. This proposed IHA would 
cover one year of a larger project for which Chevron intends to request 
additional take authorizations for subsequent facets of the project.

Description of Proposed Activity

Overview

    Chevron's Richmond Refinery Long Wharf (Long Wharf) located in San 
Francisco Bay, is the largest marine oil terminal in California. The 
Long Wharf has existed in its current location since

[[Page 18803]]

the early 1900s (Figure 1-1 in Application). The existing configuration 
of these systems have limitations to accepting more modern, fuel 
efficient vessels with shorter parallel mid-body hulls and in some 
cases do not meet current MOTEMS requirements. The purpose of the 
proposed WMEP is to comply with current MOTEMS requirements and to 
improve safety and efficiency at the Long Wharf.
    Impact and vibratory pile driving and removal will be employed 
during the proposed construction project. These actions could produce 
underwater sound at levels that could result in the injury or 
behavioral harassment of marine mammal species. Underwater construction 
activities would occur between June 1, 2018 and November 30, 2018.

Dates and Duration

    Construction activities would start in 2018, and be complete by the 
fourth quarter 2022. Pile driving activities would be timed to occur 
within the standard NMFS work windows for Endangered Species Act (ESA)-
listed fish species (June 1 through November 30) over multiple years. 
An estimated 28 days of pile driving activity are planned for 2018. 
Additional work in the future will require subsequent IHAs. The IHA 
would be effective from June 1, 2018 through May 31, 2019.

Specific Geographic Region

    The Long Wharf is located in San Francisco Bay (the Bay) just south 
of the eastern terminus of the Richmond-San Rafael Bridge (RSRB) in 
Contra Costa County. The wharf is located in the northern portion of 
the central bay, which is generally defined as the area between the 
RSRB, Golden Gate Bridge, and San Francisco-Oakland Bay Bridge (SFOBB).

Detailed Description of Specific Activity

    The proposed project would involve modifications at four berths 
(Berths 1, 2, 3, and 4). Modifications to the Long Wharf include 
replacing gangways and cranes, adding new mooring hooks and standoff 
fenders, adding new dolphins and catwalks, and modifying the fire water 
system at Berths 1, 2, 3 and/or 4, as well as the seismic retrofit to 
the Berth 4 loading platform. The type and numbers of piles to be 
installed, as well as those that will be removed during the 2018-2022 
period are summarized in Table 1. This work would be covered under 
multiple IHAs.
    The combined modifications to Berths 1 to 4 would require the 
installation of 141 new concrete piles to support new and replacement 
equipment and their associated structures. The Berth 4 loading platform 
would add eight, 60-inch diameter steel piles as part of the seismic 
retrofit. The project would also add four clusters of 13 composite 
piles each (52 total) as markers and protection of the new batter 
(driven at an angle) piles on the east side of the Berth 4 retrofit. 
The project would remove 106 existing timber piles, two existing 
18[hyphen]inch and two existing 24[hyphen]inch concrete piles. A total 
of 12 temporary piles would also be installed and removed during the 
seismic retrofit of Berth 4.
BILLING CODE 3510-22-P

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[GRAPHIC] [TIFF OMITTED] TN30AP18.000

BILLING CODE 3510-22-C
    Completion of the modifications will require cutting holes in the 
concrete decking of the Wharf to allow piles to be driven. The removal 
of structures and portion of concrete decking may involve the use of 
jackhammers to break up concrete, torches to cut metal, and various 
cutting and grinding power tools. This work will occur at various times 
throughout the construction schedule. When there is potential for 
construction debris to fall into the water below the Wharf, temporary 
work platforms will be used to capture debris. A typical debris 
catchment system that has been previously used at the Wharf consists of 
a platform suspended beneath the deck or in some cases a smaller 
platform immediately below the work area, and a second larger platform 
beneath that. Debris that falls on the platform is collected and 
disposed of in an appropriate manner.
    Planned modifications at Berth 1 include replacing a gangway to 
accommodate barges and add a new raised fire monitor; constructing a 
new 24foot (ft) x 20ft mooring dolphin and hook to accommodate barges 
and; constructing a new 24ft x 25ft breasting dolphin and 13ft x 26ft 
breasting point with standoff fenders to accommodate barges. The new 
breasting dolphin will require removal of an existing catwalk and two 
piles and replacing with a new catwalk at a slightly different 
location, and adding a short catwalk to provide access to the breasting 
dolphin. A portion of the existing gangway will be removed. The 
remaining portion is used for other existing services located on its 
structure. Much of this work will be above the water or on the Wharf 
deck. The mooring dolphin and hook, breasting dolphin, and new gangway 
will require installation of 42 new 24-inch square concrete piles using 
impact driving methods.
    Planned modifications at Berth 2 include installing a new gangway 
to replace portable gangway and add a new elevated fire monitor; 
replacing one bollard with a new hook; installing four new standoff 
fenders (to replace timber fender pile system); replacing existing 
auxiliary and hose cranes and vapor recovery crane to accommodate the 
new standoff fenders, and; removing the

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existing timber fender pile system along the length of the Berth 
(~650ft).
    Three (3) existing brace piles (22-inch square concrete jacketed 
timber piles) would be removed by cutting below the mud line if 
possible. These modifications will require the installation of 51 new 
24-inch square concrete piles, using impact driving methods, to support 
the gangway, standoff fenders, hose crane, and auxiliary crane. To keep 
Berth 2 operational during construction, four temporary ``Yokohama'' 
fenders will be installed, supported by 36 temporary 14-inch H-piles 
driven using vibratory methods. It is expected that the H-piles would 
largely sink under their own weight and would require very little 
driving. The H-piles and temporary fenders will be removed once the 
permanent standoff fenders are complete. The auxiliary and hose cranes 
are being replaced with cranes with longer reach to accommodate the 
additional distance of the new standoff fenders. The new vapor recovery 
crane would be mounted on an existing pedestal and not require 
in[hyphen]water work.
    Planned modifications at Berth 3 include installing new fixed 
gangway to replace portable gangway and add a new raised fire monitor. 
The gangway would be supported by four, 24-inch square concrete piles. 
This would be the only in-water work for modifications at Berth 3.
    Planned modifications at Berth 4 include installing two new 36ft x 
20ft dolphins with standoff fenders (two per dolphin) and two catwalks 
as well as seismically retrofitting the Berth 4 loading platform 
including bolstering and relocation of piping and electrical 
facilities. The new fenders would add 44 new 24-inch square concrete 
piles. The seismic retrofit would structurally stiffen the Berth 4 
Loading Platform under seismic loads. This will require cutting holes 
in the concrete decking and driving eight, 60-inch diameter hollow 
steel batter (angled) piles, using impact pile driving. To accommodate 
the new retrofit, an existing sump will be replaced with a new sump and 
two, 24-inch square concrete piles will be removed or cut to the 
mudline. To drive the 60-inch batter piles, eight temporary steel 
piles, 36 inches in diameter, will be needed to support templates for 
the batter piles during driving. Two templates are required, each 24ft 
by 4ft and supported by up to four 36-inch steel pipe piles. The 
templates will be above water.
    The proposed project would also add 4 clusters of 13 composite 
piles each (52 total composite piles) as markers and protection of the 
new batter piles on the east side of the retrofit.
    Note that the proposed IHA will only cover pile driving and removal 
that will occur during the 2018 work season, as provided in Table 2.

                               Table 2--Pile Driving Summary for 2018 Work Season
----------------------------------------------------------------------------------------------------------------
                                                                                     Number of       Number of
                   Pile type                            Pile driver type               piles       driving days
----------------------------------------------------------------------------------------------------------------
36-inch steel template pile...................  Vibratory.......................               8               2
Concrete pile removal.........................  Vibratory.......................               5               1
24-inch concrete..............................  Impact..........................               8               8
14-inch H pile installation (for temporary      Vibratory/Impact *..............              36              12
 fenders).
Timber pile removal...........................  Vibratory.......................              53               5
----------------------------------------------------------------------------------------------------------------
* A vibratory driver will be preferentially used for installation of the temporary H piles. In the event that
  the pile hits a buried obstruction and can no longer be advanced with a vibratory driver, and impact hammer
  may be used.

    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 Specified Activities

    Sections 3 and 4 of the application summarize available information 
regarding status and trends, distribution and habitat preferences, and 
behavior and life history, of the potentially affected species. 
Additional information regarding population trends and threats may be 
found in NMFS's Stock Assessment Reports (SAR; www.nmfs.noaa.gov/pr/sars/) and more general information about these species (e.g., physical 
and behavioral descriptions) may be found on NMFS's website
    Table 3 lists all species with expected potential for occurrence in 
the Bay near the project area and summarizes information related to the 
population or stock, including regulatory status under the MMPA and ESA 
and potential biological removal (PBR), where known. 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 (as described in 
NMFS's SARs). While no mortality is anticipated or authorized here, PBR 
and annual serious injury and mortality from anthropogenic sources are 
included here as gross indicators of the status of the species and 
other threats.
    Marine mammal abundance estimates presented in this document 
represent the total number of individuals that make up a given stock or 
the total number estimated within a particular study or survey area. 
NMFS's stock abundance estimates for most species represent the total 
estimate of individuals within the geographic area, if known, that 
comprises that stock. For some species, this geographic area may extend 
beyond U.S. waters. All managed stocks in this region are assessed in 
NMFS's U.S. Pacific Marine Mammal Stock Assessments: 2016 (Carretta et 
al., 2017). All values presented in Table 3 are the most recent 
available at the time of publication and are available at http://www.nmfs.noaa.gov/pr/sars/species.htm.

[[Page 18806]]



                                     Table 3--Marine Mammals Potentially Present in the Vicinity of the Project Area
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                                                                                         ESA/ MMPA status;   Stock abundance (CV,
             Common name                  Scientific name               Stock             strategic (Y/N)      Nmin, most recent       PBR     Annual M/
                                                                                                \1\          abundance survey) \2\               SI \3\
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                                          Order Cetartiodactyla--Cetacea--Superfamily Mysticeti (baleen whales)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Family Eschrichtiidae
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Gray whale..........................  Eschrichtius robustus..  Eastern North Pacific..  -/-; (N)            20,990 (0.05, 20,125,         624        132
                                                                                                             2011).
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                                                                    Family Balaenidae
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Humpback whale......................  Megaptera novaeangliae.  California//stock......  E/D; (Y)            1,918 (0.03, 1,876,          11.0      >=6.5
                                                                                                             2014).
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                                                                   Family Delphinidae
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Bottlenose dolphin..................  Tursiops truncatus.....  California Coastal.....  -/-; (N)            453 (0.06, 346, 2011).        2.7      >=2.0
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                                                             Family Phocoenidae (porpoises)
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Harbor porpoise.....................  Phocoena Phocoena......  San Francisco-Russian    -/-; (N)            9,886 (0.51, 6,625,            66          0
                                                                River Stock.                                 2011).
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                                                         Order Carnivora--Superfamily Pinnipedia
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                      Family Otariidae (eared seals and sea lions)
--------------------------------------------------------------------------------------------------------------------------------------------------------
California sea lion.................  Zalophus californianus.  Eastern U.S. stock.....  -/-; (N)            296,750 (-, 153,337,        9,200        389
                                                                                                             2011).
Steller sea lion....................  Eumetopias jubatus.....  Eastern U.S. stock.....  -/-; (N)            41,638 (-, 41,638,          2,498        108
                                                                                                             2015).
Northern fur seal...................  Callorhinus ursinus....  California stock.......  -/-; (N)            14,050 (-, 7,524,             451        1.8
                                                                                                             2013).
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                             Family Phocidae (earless seals)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pacific harbor seal.................  Phoca vitulina.........  California stock.......  -/-; (N)            30,968 (-, 27,348,          1,641         43
                                                                                                             2012).
Northern elephant seal..............  Mirounga angustirostris  California Breeding      -/-; (N)            179,000 (-, 81,368,         4,882        8.8
                                                                stock.                                       2010).
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\1\ Endangered Species Act (ESA) status: Endangered (E), Threatened (T)/MMPA status: Depleted (D). A dash (-) indicates that the species is not listed
  under the ESA or designated as depleted under the MMPA. Under the MMPA, a strategic stock is one for which the level of direct human-caused mortality
  exceeds PBR or which is determined to be declining and likely to be listed under the ESA within the foreseeable future. Any species or stock listed
  under the ESA is automatically designated under the MMPA as depleted and as a strategic stock.
\2\ NMFS marine mammal stock assessment reports online at: www.nmfs.noaa.gov/pr/sars/. CV is coefficient of variation; Nmin is the minimum estimate of
  stock abundance. In some cases, CV is not applicable [explain if this is the case]
\3\ These values, found in NMFS's SARs, represent annual levels of human-caused mortality plus serious injury from all sources combined (e.g.,
  commercial fisheries, ship strike). Annual M/SI often cannot be determined precisely and is in some cases presented as a minimum value or range. A CV
  associated with estimated mortality due to commercial fisheries is presented in some cases.
Note: Italicized species are not expected to be taken or proposed for authorization.

    All species that could potentially occur in the proposed survey 
areas are included in Table 3. However, the temporal and/or spatial 
occurrence of humpback whales and Steller sea lions is such that take 
is not expected to occur, and they are not discussed further beyond the 
explanation provided here.
    Although 35 species of marine mammals can be found off the coast of 
California, few species venture into San Francisco Bay, and only 
Pacific harbor seals, California sea lions, and harbor porpoises, make 
the Bay a permanent home. Small numbers of gray whales are regularly 
sighted in the Bay during their yearly migration, though most sightings 
tend to occur in the Central Bay near the Golden Gate Bridge. 
Bottlenose dolphins may also occasionally occur within San Francisco 
Bay.
    Humpback whales are rare, though well-publicized, visitors to the 
interior of San Francisco Bay. A humpback whale journeyed through the 
Bay and up the Sacramento River in 1985 and re-entered the Bay in the 
fall of 1990, stranding on mudflats near Candlestick Park (Fimrite 
2005). In May 2007, a humpback whale mother and calf spent just over 
two weeks in San Francisco Bay and the Sacramento River before finding 
their way back out to sea. Although it is possible that a humpback 
whale will enter the Bay and find its way into the project area during 
construction activities, their occurrence is unlikely. Similarly, the 
Steller sea lions are rare visitors to San Francisco Bay and is not 
expected to occur in the project area during construction. As a result, 
this species is not considered further.

Pacific Harbor Seal

    The Pacific harbor seal is one of five subspecies of Phoca 
vitulina, or the common harbor seal. They are a true seal, with a 
rounded head and visible ear canal, distinct from the eared seals, or 
sea lions, which have a pointed head and an external ear. Although 
generally solitary in the water, harbor seals come ashore at 
``haulouts''--shoreline areas where pinnipeds congregate to rest, 
socialize, breed, and molt--that are used for resting, 
thermoregulation, birthing, and nursing pups. Haul-out sites are 
relatively consistent from year to year (Kopec and Harvey 1995), and 
females have been recorded returning to their own natal haulout when 
breeding (Green et al., 2006). The nearest haulout site to the project 
site is Castro Rocks, approximately 650 meters (m) north of the 
northernmost point on the Long Wharf.
    The haulout sites at Mowry Slough (~55 kilometers (km) distant from 
project site), in the South Bay, Corte Madera Marsh (~8 km distant) and 
Castro Rocks (~650 m distant), in the northern portion of the Central 
Bay, and Yerba Buena Island (~12 km distant) in the Central Bay, 
support the largest concentrations of harbor seals within the San 
Francisco Bay. The California Department of Transportation (Caltrans) 
conducted marine mammal surveys before and during seismic retrofit work

[[Page 18807]]

on the RSRB in northern San Francisco Bay. The RSRB is located north of 
the project site, The surveys included extensive monitoring of marine 
mammals at points throughout the Bay. Although the study focused on 
harbor seals hauled out at Castro Rocks and Red Rock Island near the 
RSRB, all other observed marine mammals were recorded. Monitoring took 
place from May 1998 to February 2002 (Green et al., 2002) and 
determined that at least 500 harbor seals populate San Francisco Bay. 
This estimate agrees with previous seal counts in San Francisco Bay, 
which ranged from 524 to 641 seals from 1987 to 1999 (Goals Project 
2000).
    Although births of harbor seals have not been observed at Corte 
Madera Marsh and Yerba Buena Island, a few pups have been seen at these 
sites. The main pupping areas in the San Francisco Bay are at Mowry 
Slough and Castro Rocks (Caltrans 2012). Seals haul out year-round on 
Castro Rocks during medium to low tides; few low tide sites are 
available within San Francisco Bay. The seals at Castro Rocks are 
habituated, to a degree, to some sources of human disturbance such as 
large tanker traffic and the noise from vehicle traffic on the bridge, 
but often flush into the water when small boats maneuver close by or 
when people work on the bridge (Kopec and Harvey 1995). Long-term 
monitoring studies have been conducted at the largest harbor seal 
colonies in Point Reyes National Seashore (~45 km west of the project 
site on Pacific coast) and Golden Gate National Recreation Area (~15 km 
southwest of the project site) since 1976. Castro Rocks and other haul-
outs in San Francisco Bay are part of the regional survey area for this 
study and have been included in annual survey efforts. Between 2007 and 
2012, the average number of adults observed at Castro Rocks ranged from 
126 to 166 during the breeding season (March through May) and from 92 
to 129 during the molting season (June through July) (Truchinski et 
al., 2008, Flynn et al., 2009, Codde et al., 2010, Codde et al., 2011, 
Codde et al. 2012, Codde and Allen 2013).

California Sea Lion

    The California sea lion belongs to the family Otariidae or ``eared 
seals,'' referring to the external ear flaps not shared by other 
pinniped families. While California sea lions forage and conduct many 
activities within the water, they also use haulouts. California sea 
lions breed in Southern California and along the Channel Islands during 
the spring.
    In the Bay, sea lions haul out primarily on floating docks at Pier 
39 in the Fisherman's Wharf area of the San Francisco Marina, 
approximately 12.5 km southwest of the project site. The California sea 
lions usually arrive at Pier 39 in August after returning from the 
Channel Islands (Caltrans 2013). In addition to the Pier 39 haulout, 
California sea lions haulout on buoys and similar structures throughout 
the Bay. They are seen swimming off mainly the San Francisco and Marin 
County shorelines within the Bay but may occasionally enter the project 
area to forage. Over the monitoring period for the RSRB, monitors 
sighted California sea lions on 90 occasions in the northern portion of 
the Central Bay and at least 57 times in the Central Bay. No pupping 
activity has been observed at this site or at other locations within 
the San Francisco Bay (Caltrans 2012).
    Although there is little information regarding the foraging 
behavior of the California sea lion in the San Francisco Bay, they have 
been observed foraging on a regular basis in the shipping channel south 
of Yerba Buena Island. Because California sea lions forage over a wide 
range in San Francisco Bay, it is possible that a limited number of 
individuals would be incidentally harassed during construction.

Harbor Porpoise

    The harbor porpoise is a member of the Phocoenidae family. They 
generally occur in groups of two to five individuals, and are 
considered to be shy, relatively nonsocial animals.
    In prior years, harbor porpoises were observed primarily outside of 
San Francisco Bay. The few harbor porpoises that entered did not 
venture far into the Bay. No harbor porpoises were observed during 
marine mammal monitoring conducted before and during seismic retrofit 
work on the RSRB. In recent years, there have been increasingly common 
observations of harbor porpoises within San Francisco Bay. According to 
observations by the Golden Gate Cetacean Research team, as part of 
their multi-year assessment, approximately 650 harbor porpoises have 
been observed in the San Francisco Bay, and up to 100 may occur on a 
single day (Golden Gate Cetacean Research 2017). In San Francisco Bay, 
harbor porpoises are concentrated in the vicinity of the Golden Gate 
Bridge (approximately 12 km southwest of the project site) and Angel 
Island (5.5 km southwest), with lesser numbers sighted in the vicinity 
of Alcatraz (11 km south) and west of Treasure Island (10 km southeast) 
(Keener 2011). Because this species may venture into the Bay east of 
Angel Island, there is a slight chance that a small number of 
individuals could occur in the vicinity of the proposed project.

Gray Whale

    Gray whales are large baleen whales. They are one of the most 
frequently seen whales along the California coast, easily recognized by 
their mottled gray color and lack of dorsal fin. They feed in northern 
waters primarily off the Bering, Chukchi, and western Beaufort seas 
during the summer, before heading south to the breeding and calving 
grounds off Mexico over the winter. Between December and January, late-
stage pregnant females, adult males, and immature females and males 
will migrate southward. The northward migration peaks between February 
and March. During this time, recently pregnant females, adult males, 
immature females, and females with calves move north to the feeding 
grounds (NOAA 2003). A few individuals will enter into the San 
Francisco Bay during their northward migration.
    RSRB project monitors recorded 12 living and 2 dead gray whales, 
all in either the Central Bay or San Pablo Bay, and all but 2 sightings 
occurred during the months of April and May (Winning 2008). One gray 
whale was sighted in June and one in October (the specific years were 
unreported). The Oceanic Society has tracked gray whale sightings since 
they began returning to the Bay regularly in the late 1990s. The 
Oceanic Society data show that all age classes of gray whales are 
entering the Bay and that they enter as singles or in groups of up to 
five individuals. However, the data do not distinguish between 
sightings of gray whales and number of individual whales (Winning 
2008). It is possible that a small number of gray whales enter the Bay 
in any given year, typically from March to May. However, this is 
outside of the June to November window when pile driving would occur.

Bottlenose Dolphin

    The range of the bottlenose dolphin has expanded northward along 
the Pacific Coast since the 1982-1983 El Ni[ntilde]o (Carretta et al., 
2013; Wells and Baldridge 1990). They have been observed along the 
coast in Half Moon Bay, San Mateo, Ocean Beach in San Francisco, and 
Rodeo Beach in Marin County. Observations indicate that bottlenose 
dolphin occasionally enter San Francisco Bay, sometimes foraging for 
fish in Fort Point Cove, just east of the Golden Gate Bridge (Golden 
Gate Cetacean Research 2014). While individuals of this species 
occasionally enter San Francisco Bay, observations indicate that they 
generally remain in

[[Page 18808]]

proximity to the Golden Gate near the mouth of the Bay. However, a 
limited number may approach the project area during in-water 
construction.

Marine Mammal Hearing

    Hearing is the most important sensory modality for marine mammals 
underwater, and exposure to anthropogenic sound can have deleterious 
effects. To appropriately assess the potential effects of exposure to 
sound, it is necessary to understand the frequency ranges marine 
mammals are able to hear. Current data indicate that not all marine 
mammal species have equal hearing capabilities (e.g., Richardson et 
al., 1995; Wartzok and Ketten, 1999; Au and Hastings, 2008). To reflect 
this, Southall et al. (2007) recommended that marine mammals be divided 
into functional hearing groups based on directly measured or estimated 
hearing ranges on the basis of available behavioral response data, 
audiograms derived using auditory evoked potential techniques, 
anatomical modeling, and other data. Note that no direct measurements 
of hearing ability have been successfully completed for mysticetes 
(i.e., low-frequency cetaceans). Subsequently, NMFS (2016) described 
generalized hearing ranges for these marine mammal hearing groups. 
Generalized hearing ranges were chosen based on the approximately 65 
decibels (dB) threshold from the normalized composite audiograms, with 
the exception for lower limits for low-frequency cetaceans where the 
lower bound was deemed to be biologically implausible and the lower 
bound from Southall et al. (2007) retained. The functional groups and 
the associated frequencies are indicated below (note that these 
frequency ranges correspond to the range for the composite group, with 
the entire range not necessarily reflecting the capabilities of every 
species within that group):
     Low-frequency cetaceans (mysticetes): Generalized hearing 
is estimated to occur between approximately 7 hertz (Hz) and 35 
kilohertz (kHz).
     Mid-frequency cetaceans (larger toothed whales, beaked 
whales, and most delphinids): Generalized hearing is estimated to occur 
between approximately 150 Hz and 160 kHz.
     High-frequency cetaceans (porpoises, river dolphins, and 
members of the genera Kogia and Cephalorhynchus; including two members 
of the genus Lagenorhynchus, on the basis of recent echolocation data 
and genetic data): Generalized hearing is estimated to occur between 
approximately 275 Hz and 160 kHz.
     Pinnipeds in water; Phocidae (true seals): Generalized 
hearing is estimated to occur between approximately 50 Hz to 86 kHz.
     Pinnipeds in water; Otariidae (eared seals): Generalized 
hearing is estimated to occur between 60 Hz and 39 kHz.
    The pinniped functional hearing group was modified from Southall et 
al. (2007) on the basis of data indicating that phocid species have 
consistently demonstrated an extended frequency range of hearing 
compared to otariids, especially in the higher frequency range 
(Hemil[auml] et al., 2006; Kastelein et al., 2009; Reichmuth and Holt, 
2013).
    For more detail concerning these groups and associated frequency 
ranges, please see NMFS (2016) for a review of available information. 
Seven marine mammal species (three cetacean and four pinniped (two 
otariid and two phocid) species) have the reasonable potential to co-
occur with the proposed activities. Please refer to Table 3. Of the 
cetacean species that may be present, one is classified as low-
frequency cetaceans (i.e., gray whale), one is classified as mid-
frequency cetaceans (i.e., bottlenose dolphin), and one is classified 
as high-frequency cetaceans (i.e., harbor porpoise).

Potential Effects of Specified Activities on Marine Mammals and Their 
Habitat

    This section includes a summary and discussion of the ways that 
components of the specified activity may impact marine mammals and 
their habitat. The ``Estimated Take by Incidental Harassment'' section 
later in this document includes a quantitative analysis of the number 
of individuals that are expected to be taken by this activity. The 
``Negligible Impact Analysis and Determination'' section considers the 
content 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.

Description of Sound Sources

    Sound travels in waves, the basic components of which are 
frequency, wavelength, velocity, and amplitude. Frequency is the number 
of pressure waves that pass by a reference point per unit of time and 
is measured in Hz or cycles per second. Wavelength is the distance 
between two peaks of a sound wave; lower frequency sounds have longer 
wavelengths than higher frequency sounds and attenuate (decrease) more 
rapidly in shallower water. Amplitude is the height of the sound 
pressure wave or the `loudness' of a sound and is typically measured 
using the dB scale. A dB is the ratio between a measured pressure (with 
sound) and a reference pressure (sound at a constant pressure, 
established by scientific standards). It is a logarithmic unit that 
accounts for large variations in amplitude; therefore, relatively small 
changes in dB ratings correspond to large changes in sound pressure. 
When referring to sound pressure levels (SPLs; the sound force per unit 
area), sound is referenced in the context of underwater sound pressure 
to 1 micro pascal ([mu]Pa). One pascal is the pressure resulting from a 
force of one newton exerted over an area of one square meter (m\2\). 
The source level (SL) represents the sound level at a distance of 1 m 
from the source (referenced to 1 [mu]Pa). The received level is the 
sound level at the listener's position. Note that all underwater sound 
levels in this document are referenced to a pressure of 1 [micro]Pa and 
all airborne sound levels in this document are referenced to a pressure 
of 20 [micro]Pa.
    Root mean square (rms) is the quadratic mean sound pressure over 
the duration of an impulse. Rms is calculated by squaring all of the 
sound amplitudes, averaging the squares, and then taking the square 
root of the average (Urick 1983). Rms accounts for both positive and 
negative values; squaring the pressures makes all values positive so 
that they may be accounted for in the summation of pressure levels 
(Hastings and Popper 2005). This measurement is often used in the 
context of discussing behavioral effects, in part because behavioral 
effects, which often result from auditory cues, may be better expressed 
through averaged units than by peak pressures.
    When underwater objects vibrate or activity occurs, sound-pressure 
waves are created. These waves alternately compress and decompress the 
water as the sound wave travels. Underwater sound waves radiate in all 
directions away from the source (similar to ripples on the surface of a 
pond), except in cases where the source is directional. The 
compressions and decompressions associated with sound waves are 
detected as changes in pressure by aquatic life and man-made sound 
receptors such as hydrophones.
    Even in the absence of sound from the specified activity, the 
underwater environment is typically loud due to ambient sound. Ambient 
sound is defined as environmental background sound levels lacking a 
single source or point (Richardson et al.,1995), and the

[[Page 18809]]

sound level of a region is defined by the total acoustical energy being 
generated by known and unknown sources. These sources may include 
physical (e.g., waves, earthquakes, ice, atmospheric sound), biological 
(e.g., sounds produced by marine mammals, fish, and invertebrates), and 
anthropogenic sound (e.g., vessels, dredging, aircraft, construction). 
A number of sources contribute to ambient sound, including the 
following (Richardson et al., 1995):
     Wind and waves: The complex interactions between wind and 
water surface, including processes such as breaking waves and wave-
induced bubble oscillations and cavitation, are a main source of 
naturally occurring ambient noise for frequencies between 200 Hz and 50 
kHz (Mitson, 1995). In general, ambient sound levels tend to increase 
with increasing wind speed and wave height. Surf noise becomes 
important near shore, with measurements collected at a distance of 8.5 
km from shore showing an increase of 10 dB in the 100 to 700 Hz band 
during heavy surf conditions;
     Precipitation: Sound from rain and hail impacting the 
water surface can become an important component of total noise at 
frequencies above 500 Hz, and possibly down to 100 Hz during quiet 
times;
     Biological: Marine mammals can contribute significantly to 
ambient noise levels, as can some fish and shrimp. The frequency band 
for biological contributions is from approximately 12 Hz to over 100 
kHz; and
     Anthropogenic: Sources of ambient noise related to human 
activity include transportation (surface vessels and aircraft), 
dredging and construction, oil and gas drilling and production, seismic 
surveys, sonar, explosions, and ocean acoustic studies. Shipping noise 
typically dominates the total ambient noise for frequencies between 20 
and 300 Hz. In general, the frequencies of anthropogenic sounds are 
below 1 kHz and, if higher frequency sound levels are created, they 
attenuate rapidly (Richardson et al., 1995). Sound from identifiable 
anthropogenic sources other than the activity of interest (e.g., a 
passing vessel) is sometimes termed background sound, as opposed to 
ambient sound.
    The sum of the various natural and anthropogenic sound sources at 
any given location and time--which comprise ``ambient'' or 
``background'' sound--depends not only on the source levels (as 
determined by current weather conditions and levels of biological and 
shipping activity) but also on the ability of sound to propagate 
through the environment. In turn, sound propagation is dependent on the 
spatially and temporally varying properties of the water column and sea 
floor, and is frequency-dependent. As a result of the dependence on a 
large number of varying factors, ambient sound levels can be expected 
to vary widely over both coarse and fine spatial and temporal scales. 
Sound levels at a given frequency and location can vary by 10-20 dB 
from day to day (Richardson et al., 1995). The result is that, 
depending on the source type and its intensity, sound from the 
specified activity may be a negligible addition to the local 
environment or could form a distinctive signal that may affect marine 
mammals.
    In-water construction activities associated with the project would 
include impact pile driving, vibratory pile driving and vibratory pile 
extraction. The sounds produced by these activities fall into one of 
two general sound types: Pulsed and non-pulsed (defined in the 
following paragraphs). The distinction between these two sound types is 
important because they have differing potential to cause physical 
effects, particularly with regard to hearing (e.g., Ward, 1997 in 
Southall et al., 2007). Please see Southall et al., (2007) for an in-
depth discussion of these concepts.
    Pulsed sound sources (e.g., explosions, gunshots, sonic booms, 
impact pile driving) produce signals that are brief (typically 
considered to be less than one second), broadband, atonal transients 
(ANSI, 1986; Harris, 1998; ISO, 2003) and occur either as isolated 
events or repeated in some succession. Pulsed sounds are all 
characterized by a relatively rapid rise from ambient pressure to a 
maximal pressure value followed by a rapid decay period that may 
include a period of diminishing, oscillating maximal and minimal 
pressures, and generally have an increased capacity to induce physical 
injury as compared with sounds that lack these features.
    Non-pulsed sounds can be tonal, narrowband, or broadband, brief or 
prolonged, and may be either continuous or non-continuous (ANSI, 1995; 
NIOSH, 1998). Some of these non-pulsed sounds can be transient signals 
of short duration but without the essential properties of pulses (e.g., 
rapid rise time). Examples of non-pulsed sounds include those produced 
by vessels, aircraft, machinery operations such as drilling, vibratory 
pile driving, and active sonar systems (such as those used by the U.S. 
Navy). The duration of such sounds, as received at a distance, can be 
greatly extended in a highly reverberant environment.
    Impact hammers operate by repeatedly dropping a heavy piston onto a 
pile to drive the pile into the substrate. Sound generated by impact 
hammers is characterized by rapid rise times and high peak levels, a 
potentially injurious combination (Hastings and Popper 2005). Vibratory 
hammers install piles by vibrating them and allowing the weight of the 
hammer to push them into the sediment. Vibratory hammers produce 
significantly less sound than impact hammers. Peak SPLs may be 180 dB 
or greater, but are generally 10 to 20 dB lower than SPLs generated 
during impact pile driving of the same-sized pile (Oestman et al., 
2009). Rise time is slower, reducing the probability and severity of 
injury, and sound energy is distributed over a greater amount of time 
(Nedwell and Edwards 2002).

Acoustic Impacts

    Please refer to the information given previously (Description of 
Sound Sources) regarding sound, characteristics of sound types, and 
metrics used in this document. Anthropogenic sounds cover a broad range 
of frequencies and sound levels and can have a range of highly variable 
impacts on marine life, from none or minor to potentially severe 
responses, depending on received levels, duration of exposure, 
behavioral context, and various other factors. The potential effects of 
underwater sound from active acoustic sources can potentially result in 
one or more of the following: Temporary or permanent hearing 
impairment, non-auditory physical or physiological effects, behavioral 
disturbance, stress, and masking (Richardson et al., 1995; Gordon et 
al., 2004; Nowacek et al., 2007; Southall et al., 2007). The degree of 
effect is intrinsically related to the signal characteristics, received 
level, distance from the source, and duration of the sound exposure. In 
general, sudden, high level sounds can cause hearing loss, as can 
longer exposures to lower level sounds. Temporary or permanent loss of 
hearing will occur almost exclusively for noise within an animal's 
hearing range. In this section, we first describe specific 
manifestations of acoustic effects before providing discussion specific 
to the proposed construction activities in the next section.
    Permanent Threshold Shift--Marine mammals exposed to high-intensity 
sound, or to lower-intensity sound for prolonged periods, can 
experience hearing threshold shift (TS), which is the loss of hearing 
sensitivity at certain frequency ranges (Kastak et al., 1999; Schlundt 
et al., 2000; Finneran et al.,

[[Page 18810]]

2002, 2005). TS can be permanent (PTS), in which case the loss of 
hearing sensitivity is not fully recoverable, or temporary (TTS), in 
which case the animal's hearing threshold would recover over time 
(Southall et al., 2007). Repeated sound exposure that leads to TTS 
could cause PTS. In severe cases of PTS, there can be total or partial 
deafness, while in most cases the animal has an impaired ability to 
hear sounds in specific frequency ranges (Kryter 1985).
    When PTS occurs, there is physical damage to the sound receptors in 
the ear (i.e., tissue damage), whereas TTS represents primarily tissue 
fatigue and is reversible (Southall et al., 2007). In addition, other 
investigators have suggested that TTS is within the normal bounds of 
physiological variability and tolerance and does not represent physical 
injury (e.g., Ward 1997). Therefore, NMFS does not consider TTS to 
constitute auditory injury.
    Relationships between TTS and PTS thresholds have not been studied 
in marine mammals--PTS data exists only for a single harbor seal 
(Kastak et al., 2008)--but are assumed to be similar to those in humans 
and other terrestrial mammals. PTS typically occurs at exposure levels 
at least several dB above (a 40-dB threshold shift approximates PTS 
onset; e.g., Kryter et al., 1966; Miller 1974) that inducing mild TTS 
(a 6-dB threshold shift approximates TTS onset; e.g., Southall et al., 
2007). Based on data from terrestrial mammals, a precautionary 
assumption is that the PTS thresholds for impulse sounds (such as 
impact pile driving pulses as received close to the source) are at 
least six dB higher than the TTS threshold on a peak-pressure basis and 
PTS cumulative sound exposure level thresholds are 15 to 20 dB higher 
than TTS cumulative sound exposure level thresholds (Southall et al., 
2007).
    Temporary threshold shift--TTS is the mildest form of hearing 
impairment that can occur during exposure to sound (Kryter 1985). While 
experiencing TTS, the hearing threshold rises, and a sound must be at a 
higher level in order to be heard. In terrestrial and marine mammals, 
TTS can last from minutes or hours to days (in cases of strong TTS). In 
many cases, hearing sensitivity recovers rapidly after exposure to the 
sound ends.
    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. 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.
    Currently, TTS data only exist for four species of cetaceans 
(bottlenose dolphin, beluga whale (Delphinapterus leucas), harbor 
porpoise, and Yangtze finless porpoise (Neophocoena asiaeorientalis)); 
and three species of pinnipeds (northern elephant seal, harbor seal, 
and California sea lion exposed to a limited number of sound sources 
(i.e., mostly tones and octave-band noise) in laboratory settings 
(e.g., Finneran et al., 2002; Nachtigall et al., 2004; Kastak et al., 
2005; Lucke et al., 2009; Popov et al., 2011). In general, harbor seals 
(Kastak et al., 2005; Kastelein et al., 2012a) and harbor porpoises 
(Lucke et al., 2009; Kastelein et al., 2012b) have a lower TTS onset 
than other measured pinniped or cetacean species. Additionally, the 
existing marine mammal TTS data come from a limited number of 
individuals within these species. There are no data available on noise-
induced hearing loss for mysticetes. For summaries of data on TTS in 
marine mammals or for further discussion of TTS onset thresholds, 
please see Southall et al. (2007), Finneran and Jenkins (2012), and 
Finneran (2015).
    Behavioral effects--Behavioral disturbance may include a variety of 
effects, including subtle changes in behavior (e.g., minor or brief 
avoidance of an area or changes in vocalizations), more conspicuous 
changes in similar behavioral activities, and more sustained and/or 
potentially severe reactions, such as displacement from or abandonment 
of high-quality habitat. Behavioral responses to sound are highly 
variable and context-specific and any reactions depend on numerous 
intrinsic and extrinsic factors (e.g., species, state of maturity, 
experience, current activity, reproductive state, auditory sensitivity, 
time of day), as well as the interplay between factors (e.g., 
Richardson et al., 1995; Wartzok et al., 2003; Southall et al., 2007; 
Weilgart, 2007; Archer et al., 2010). Behavioral reactions can vary not 
only among individuals but also within an individual, depending on 
previous experience with a sound source, context, and numerous other 
factors (Ellison et al., 2012), and can vary depending on 
characteristics associated with the sound source (e.g., whether it is 
moving or stationary, number of sources, distance from the source). 
Please see Appendices B-C of Southall et al. (2007) for a review of 
studies involving marine mammal behavioral responses to sound.
    Habituation can occur when an animal's response to a stimulus wanes 
with repeated exposure, usually in the absence of unpleasant associated 
events (Wartzok et al., 2003). Animals are most likely to habituate to 
sounds that are predictable and unvarying. It is important to note that 
habituation is appropriately considered as a ``progressive reduction in 
response to stimuli that are perceived as neither aversive nor 
beneficial,'' rather than as, more generally, moderation in response to 
human disturbance (Bejder et al., 2009). The opposite process is 
sensitization, when an unpleasant experience leads to subsequent 
responses, often in the form of avoidance, at a lower level of 
exposure. As noted, behavioral state may affect the type of response. 
For example, animals that are resting may show greater behavioral 
change in response to disturbing sound levels than animals that are 
highly motivated to remain in an area for feeding (Richardson et al., 
1995; NRC, 2003; Wartzok et al., 2003). Controlled experiments with 
captive marine mammals have showed pronounced behavioral reactions, 
including avoidance of loud sound sources (Ridgway et al., 1997; 
Finneran et al., 2003). Observed responses of wild marine mammals to 
loud pulsed sound sources (typically seismic airguns or acoustic 
harassment devices) have been varied but often consist of avoidance 
behavior or other behavioral changes suggesting discomfort (Morton and 
Symonds, 2002; see also Richardson et al., 1995; Nowacek et al., 2007).
    Available studies show wide variation in response to underwater 
sound; therefore, it is difficult to predict specifically how any given 
sound in a particular instance might affect marine mammals perceiving 
the signal. If a marine mammal does react briefly to an underwater 
sound by changing its behavior or moving a small distance, the impacts 
of the change are unlikely to be significant to the individual, let 
alone the stock or population. However, if a sound source displaces 
marine mammals from an important feeding or breeding area for a 
prolonged period, impacts on individuals and populations could be 
significant (e.g., Lusseau and

[[Page 18811]]

Bejder, 2007; Weilgart, 2007; NRC, 2003). However, there are broad 
categories of potential response, which we describe in greater detail 
here, that include alteration of dive behavior, alteration of foraging 
behavior, effects to breathing, interference with or alteration of 
vocalization, avoidance, and flight.
    Changes in dive behavior can vary widely, and may consist of 
increased or decreased dive times and surface intervals as well as 
changes in the rates of ascent and descent during a dive (e.g., Frankel 
and Clark, 2000; Costa et al., 2003; Ng and Leung, 2003; Nowacek et 
al.; 2004; Goldbogen et al., 2013a,b). Variations in dive behavior may 
reflect interruptions in biologically significant activities (e.g., 
foraging) or they may be of little biological significance. The impact 
of an alteration to dive behavior resulting from an acoustic exposure 
depends on what the animal is doing at the time of the exposure and the 
type and magnitude of the response.
    Disruption of feeding behavior can be difficult to correlate with 
anthropogenic sound exposure, so it is usually inferred by observed 
displacement from known foraging areas, the appearance of secondary 
indicators (e.g., bubble nets or sediment plumes), or changes in dive 
behavior. As for other types of behavioral response, the frequency, 
duration, and temporal pattern of signal presentation, as well as 
differences in species sensitivity, are likely contributing factors to 
differences in response in any given circumstance (e.g., Croll et al., 
2001; Nowacek et al.,; 2004; Madsen et al., 2006; Yazvenko et al., 
2007). A determination of whether foraging disruptions incur fitness 
consequences would require information on or estimates of the energetic 
requirements of the affected individuals and the relationship between 
prey availability, foraging effort and success, and the life history 
stage of the animal.
    Variations in respiration naturally vary with different behaviors 
and alterations to breathing rate as a function of acoustic exposure 
can be expected to co-occur with other behavioral reactions, such as a 
flight response or an alteration in diving. However, respiration rates 
in and of themselves may be representative of annoyance or an acute 
stress response. Various studies have shown that respiration rates may 
either be unaffected or could increase, depending on the species and 
signal characteristics, again highlighting the importance in 
understanding species differences in the tolerance of underwater noise 
when determining the potential for impacts resulting from anthropogenic 
sound exposure (e.g., Kastelein et al., 2001, 2005b, 2006; Gailey et 
al., 2007).
    Marine mammals vocalize for different purposes and across multiple 
modes, such as whistling, echolocation click production, calling, and 
singing. Changes in vocalization behavior in response to anthropogenic 
noise can occur for any of these modes and may result from a need to 
compete with an increase in background noise or may reflect increased 
vigilance or a startle response. For example, in the presence of 
potentially masking signals, humpback whales and killer whales have 
been observed to increase the length of their songs (Miller et al., 
2000; Fristrup et al., 2003; Foote et al., 2004), while right whales 
have been observed to shift the frequency content of their calls upward 
while reducing the rate of calling in areas of increased anthropogenic 
noise (Parks et al., 2007b). In some cases, animals may cease sound 
production during production of aversive signals (Bowles et al., 1994).
    Avoidance is the displacement of an individual from an area or 
migration path as a result of the presence of a sound or other 
stressors, and is one of the most obvious manifestations of disturbance 
in marine mammals (Richardson et al., 1995). For example, gray whales 
are known to change direction--deflecting from customary migratory 
paths--in order to avoid noise from seismic surveys (Malme et al., 
1984). Avoidance may be short-term, with animals returning to the area 
once the noise has ceased (e.g., Bowles et al., 1994; Goold, 1996; 
Stone et al., 2000; Morton and Symonds, 2002; Gailey et al., 2007). 
Longer-term displacement is possible, however, which may lead to 
changes in abundance or distribution patterns of the affected species 
in the affected region if habituation to the presence of the sound does 
not occur (e.g., Blackwell et al., 2004; Bejder et al., 2006).
    A flight response is a dramatic change in normal movement to a 
directed and rapid movement away from the perceived location of a sound 
source. The flight response differs from other avoidance responses in 
the intensity of the response (e.g., directed movement, rate of 
travel). Relatively little information on flight responses of marine 
mammals to anthropogenic signals exist, although observations of flight 
responses to the presence of predators have occurred (Connor and 
Heithaus 1996). The result of a flight response could range from brief, 
temporary exertion and displacement from the area where the signal 
provokes flight to, in extreme cases, marine mammal strandings (Evans 
and England 2001). However, it should be noted that response to a 
perceived predator does not necessarily invoke flight (Ford and Reeves 
2008), and whether individuals are solitary or in groups may influence 
the response.
    Behavioral disturbance can also impact marine mammals in more 
subtle ways. Increased vigilance may result in costs related to 
diversion of focus and attention (i.e., when a response consists of 
increased vigilance, it may come at the cost of decreased attention to 
other critical behaviors such as foraging or resting). These effects 
have generally not been demonstrated for marine mammals, but studies 
involving fish and terrestrial animals have shown that increased 
vigilance may substantially reduce feeding rates (e.g., Beauchamp and 
Livoreil, 1997; Fritz et al., 2002; Purser and Radford, 2011). In 
addition, chronic disturbance can cause population declines through 
reduction of fitness (e.g., decline in body condition) and subsequent 
reduction in reproductive success, survival, or both (e.g., Harrington 
and Veitch, 1992; Daan et al., 1996; Bradshaw et al., 1998). However, 
Ridgway et al. (2006) reported that increased vigilance in bottlenose 
dolphins exposed to sound over a five-day period did not cause any 
sleep deprivation or stress effects.
    Many animals perform vital functions, such as feeding, resting, 
traveling, and socializing, on a diel cycle (24-hour cycle). Disruption 
of such functions resulting from reactions to stressors such as sound 
exposure are more likely to be significant if they last more than one 
diel cycle or recur on subsequent days (Southall et al., 2007). 
Consequently, a behavioral response lasting less than one day and not 
recurring on subsequent days is not considered particularly severe 
unless it could directly affect reproduction or survival (Southall et 
al., 2007). Note that there is a difference between multi-day 
substantive behavioral reactions and multi-day anthropogenic 
activities. For example, just because an activity lasts for multiple 
days does not necessarily mean that individual animals are either 
exposed to activity-related stressors for multiple days or, further, 
exposed in a manner resulting in sustained multi-day substantive 
behavioral responses.
    Stress responses--An animal's perception of a threat may be 
sufficient to trigger stress responses consisting of some combination 
of behavioral responses, autonomic nervous system responses, 
neuroendocrine responses, or immune responses (e.g., Seyle, 1950; 
Moberg, 2000). In many cases, an animal's first and sometimes most

[[Page 18812]]

economical (in terms of energetic costs) response is behavioral 
avoidance of the potential stressor. Autonomic nervous system responses 
to stress typically involve changes in heart rate, blood pressure, and 
gastrointestinal activity. These responses have a relatively short 
duration and may or may not have a significant long-term effect on an 
animal's fitness.
    Neuroendocrine stress responses often involve the hypothalamus-
pituitary-adrenal system. Virtually all neuroendocrine functions that 
are affected by stress--including immune competence, reproduction, 
metabolism, and behavior--are regulated by pituitary hormones. Stress-
induced changes in the secretion of pituitary hormones have been 
implicated in failed reproduction, altered metabolism, reduced immune 
competence, and behavioral disturbance (e.g., Moberg, 1987; Blecha, 
2000). Increases in the circulation of glucocorticoids are also equated 
with stress (Romano et al., 2004).
    The primary distinction between stress (which is adaptive and does 
not normally place an animal at risk) and ``distress'' is the cost of 
the response. During a stress response, an animal uses glycogen stores 
that can be quickly replenished once the stress is alleviated. In such 
circumstances, the cost of the stress response would not pose serious 
fitness consequences. However, when an animal does not have sufficient 
energy reserves to satisfy the energetic costs of a stress response, 
energy resources must be diverted from other functions. This state of 
distress will last until the animal replenishes its energetic reserves 
sufficient to restore normal function.
    Relationships between these physiological mechanisms, animal 
behavior, and the costs of stress responses are well-studied through 
controlled experiments and for both laboratory and free-ranging animals 
(e.g., Holberton et al., 1996; Hood et al., 1998; Jessop et al., 2003; 
Krausman et al., 2004; Lankford et al., 2005). Stress responses due to 
exposure to anthropogenic sounds or other stressors and their effects 
on marine mammals have also been reviewed (Fair and Becker, 2000; 
Romano et al., 2002b) and, more rarely, studied in wild populations 
(e.g., Romano et al., 2002a). For example, Rolland et al. (2012) found 
that noise reduction from reduced ship traffic in the Bay of Fundy was 
associated with decreased stress in North Atlantic right whales. These 
and other studies lead to a reasonable expectation that some marine 
mammals will experience physiological stress responses upon exposure to 
acoustic stressors and that it is possible that some of these would be 
classified as ``distress.'' In addition, any animal experiencing TTS 
would likely also experience stress responses (NRC 2003).
    Auditory masking--Sound can disrupt behavior through masking, or 
interfering with, an animal's ability to detect, recognize, or 
discriminate between acoustic signals of interest (e.g., those used for 
intraspecific communication and social interactions, prey detection, 
predator avoidance, navigation) (Richardson et al., 1995). Masking 
occurs when the receipt of a sound is interfered with by another 
coincident sound at similar frequencies and at similar or higher 
intensity, and may occur whether the sound is natural (e.g., snapping 
shrimp, wind, waves, precipitation) or anthropogenic (e.g., shipping, 
sonar, seismic exploration) in origin. The ability of a noise source to 
mask biologically important sounds depends on the characteristics of 
both the noise source and the signal of interest (e.g., signal-to-noise 
ratio, temporal variability, direction), in relation to each other and 
to an animal's hearing abilities (e.g., sensitivity, frequency range, 
critical ratios, frequency discrimination, directional discrimination, 
age or TTS hearing loss), and existing ambient noise and propagation 
conditions.
    Under certain circumstances, marine mammals experiencing 
significant masking could also be impaired from maximizing their 
performance fitness in survival and reproduction. Therefore, when the 
coincident (masking) sound is man-made, it may be considered harassment 
when disrupting or altering critical behaviors. It is important to 
distinguish TTS and PTS, which persist after the sound exposure, from 
masking, which occurs during the sound exposure. Because masking 
(without resulting in TS) is not associated with abnormal physiological 
function, it is not considered a physiological effect, but rather a 
potential behavioral effect.
    The frequency range of the potentially masking sound is important 
in determining any potential behavioral impacts. For example, low-
frequency signals may have less effect on high-frequency echolocation 
sounds produced by odontocetes but are more likely to affect detection 
of mysticete communication calls and other potentially important 
natural sounds such as those produced by surf and some prey species. 
The masking of communication signals by anthropogenic noise may be 
considered as a reduction in the communication space of animals (e.g., 
Clark et al., 2009) and may result in energetic or other costs as 
animals change their vocalization behavior (e.g., Miller et al., 2000; 
Foote et al., 2004; Parks et al., 2007b; Di Iorio and Clark 2009; Holt 
et al., 2009). Masking can be reduced in situations where the signal 
and noise come from different directions (Richardson et al., 1995), 
through amplitude modulation of the signal, or through other 
compensatory behaviors (Houser and Moore 2014). Masking can be tested 
directly in captive species (e.g., Erbe, 2008), but in wild populations 
it must be either modeled or inferred from evidence of masking 
compensation. There are few studies addressing real-world masking 
sounds likely to be experienced by marine mammals in the wild (e.g., 
Branstetter et al., 2013).
    Masking affects both senders and receivers of acoustic signals and 
can potentially have long-term chronic effects on marine mammals at the 
population level as well as at the individual level. Low-frequency 
ambient sound levels have increased by as much as 20 dB (more than 
three times in terms of SPL) in the world's ocean from pre-industrial 
periods, with most of the increase from distant commercial shipping 
(Hildebrand, 2009). All anthropogenic sound sources, but especially 
chronic and lower-frequency signals (e.g., from vessel traffic), 
contribute to elevated ambient sound levels, thus intensifying masking.
    Non-auditory physiological effects--Non-auditory physiological 
effects or injuries that theoretically might occur in marine mammals 
exposed to strong underwater sound include stress, neurological 
effects, bubble formation, resonance effects, and other types of organ 
or tissue damage (Cox et al., 2006; Southall et al., 2007). Studies 
examining such effects are limited. In general, little is known about 
the potential for pile driving to cause auditory impairment or other 
physical effects in marine mammals. Available data suggest that such 
effects, if they occur at all, would presumably be limited to short 
distances from the sound source, where SLs are much higher, and to 
activities that extend over a prolonged period. The available data do 
not allow identification of a specific exposure level above which non-
auditory effects can be expected (Southall et al., 2007) or any 
meaningful quantitative predictions of the numbers (if any) of marine 
mammals that might be affected in those ways. However, the proposed 
activities do not involve the use of devices such as explosives or mid-
frequency active sonar that are associated with these types of effects. 
Therefore, non-auditory physiological

[[Page 18813]]

impacts to marine mammals are considered unlikely.
    Disturbance Reactions--Responses to continuous sound, such as 
vibratory pile installation, have not been documented as well as 
responses to pulsed sounds. With both types of pile driving, it is 
likely that the onset of pile driving could result in temporary, short 
term changes in an animal's typical behavior and/or avoidance of the 
affected area. Specific behavioral changes that may result from this 
proposed project include changing durations of surfacing and dives, 
moving direction and/or speed; 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); 
and avoidance of areas where sound sources are located. If a marine 
mammal responds to a stimulus by changing its behavior (e.g., through 
relatively minor changes in locomotion direction/speed or vocalization 
behavior), the response may or may not constitute taking at the 
individual level, and is unlikely to affect the stock or the species as 
a whole. However, if a sound source displaces marine mammals from an 
important feeding or breeding area for a prolonged period, potential 
impacts on the stock or species could potentially be significant if 
growth, survival and reproduction are affected (e.g., Lusseau and 
Bejder, 2007; Weilgart, 2007). Note that the significance of many of 
these behavioral disturbances is difficult to predict, especially if 
the detected disturbances appear minor.
    Airborne Acoustic Effects from the Proposed Activities--Pinnipeds 
that occur near the project site could be exposed to airborne sounds 
associated with pile driving that have the potential to cause 
behavioral harassment, depending on their distance from pile driving 
activities. Cetaceans are not expected to be exposed to airborne sounds 
that would result in harassment as defined under the MMPA.
    Airborne noise will primarily be an issue for pinnipeds that are 
swimming or hauled out near the project site within the range of noise 
levels elevated above the acoustic criteria. We recognize that 
pinnipeds in the water could be exposed to airborne sound that may 
result in behavioral harassment when looking with heads above water. 
Most likely, airborne sound would cause behavioral responses similar to 
those discussed above in relation to underwater sound. However, these 
animals would previously have been ``taken'' as a result of exposure to 
underwater sound above the behavioral harassment thresholds, which are 
in all cases larger than those associated with airborne sound. Thus, 
the behavioral harassment of these animals is already accounted for in 
these estimates of potential take. Multiple instances of exposure to 
sound above NMFS' thresholds for behavioral harassment are not believed 
to result in increased behavioral disturbance, in either nature or 
intensity of disturbance reaction.
    Potential Pile Driving Effects on Prey--Construction activities 
would produce continuous (i.e., vibratory pile driving) sounds and 
pulsed (i.e., impact driving) sounds. Fish react to sounds that are 
especially strong and/or intermittent low-frequency sounds. Short 
duration, sharp sounds can cause overt or subtle changes in fish 
behavior and local distribution. Hastings and Popper (2005) identified 
several studies that suggest fish may relocate to avoid certain areas 
of sound energy. Additional studies have documented effects of pile 
driving on fish, although several are based on studies in support of 
large, multiyear bridge construction projects (e.g., Scholik and Yan, 
2001, 2002; Popper and Hastings, 2009). Sound pulses at received levels 
of 160 dB may cause subtle changes in fish behavior. SPLs of 180 dB may 
cause noticeable changes in behavior (Pearson et al., 1992; Skalski et 
al., 1992). SPLs of sufficient strength have been known to cause injury 
to fish and fish mortality.
    The most likely impact to fish from pile driving activities at the 
project area would be temporary behavioral avoidance within an 
undetermined portion of the affected area. The duration of fish 
avoidance of this area after pile driving stops is unknown, but a rapid 
return to normal recruitment, distribution and behavior is anticipated. 
In general, impacts to marine mammal prey species from the proposed 
project are expected to be minor and temporary due to the relatively 
short and intermittent timeframe (up to 28 driving days over 6 months) 
of pile driving and extraction.
    Effects to Foraging Habitat--Pile installation may temporarily 
impact foraging habitat by increasing turbidity resulting from 
suspended sediments. Any increases would be temporary, localized, and 
minimal. The contractor must comply with state water quality standards 
during these operations by limiting the extent of turbidity to the 
immediate project area. In general, turbidity associated with pile 
installation is localized to about a 25ft radius around the pile 
(Everitt et al., 1980). Furthermore, water quality impacts are expected 
to be negligible because the project area occurs in a high energy, 
dynamic area with strong tidal currents. Cetaceans are not expected to 
be close enough to the project pile driving areas to experience effects 
of turbidity, and any pinnipeds in the area could avoid localized areas 
of turbidity. Therefore, the impact from increased turbidity levels is 
expected to be discountable to marine mammals.
    It is important to note that pile driving and removal activities at 
the project site will not obstruct movements or migration of marine 
mammals.
    In summary, given the relatively short (28 days) and intermittent 
nature of sound associated with individual pile driving and extraction 
events and the relatively small area that would be affected, pile 
driving activities associated with the proposed action are not likely 
to have a permanent, adverse effect on any fish habitat, or populations 
of fish species. Thus, any impacts to marine mammal habitat are not 
expected to cause significant or long-term consequences for individual 
marine mammals or their populations.

Estimated Take

    This section provides an estimate of the number of incidental takes 
proposed for authorization through this IHA, which will inform both 
NMFS' consideration of ``small numbers'' 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, section 3(18) of the MMPA defines ``harassment'' as any act of 
pursuit, torment, or annoyance which (i) has the potential to injure a 
marine mammal or marine mammal stock in the wild (Level A harassment); 
or (ii) has the potential to disturb a marine mammal or marine mammal 
stock in the wild by causing disruption of behavioral patterns, 
including, but not limited to, migration, breathing, nursing, breeding, 
feeding, or sheltering (Level B harassment).
    Authorized takes would primarily be by Level B harassment, as use 
of the acoustic source (i.e., pile driving) has the potential to result 
in disruption of behavioral patterns for individual marine mammals. 
There is also some potential for auditory injury (Level A harassment) 
to result, primarily for high frequency species and a single phocid 
species due to larger predicted auditory injury zones. Auditory injury 
is unlikely to occur for low-frequency, mid-frequency species, or 
pinniped groups, with the exception of harbor seals. The proposed 
mitigation and monitoring measures are expected to minimize the

[[Page 18814]]

severity of such taking to the extent practicable.
    As described previously, no mortality is anticipated or proposed to 
be authorized for this activity. Below we describe how the take is 
estimated.
    Described in the most basic way, we estimate take by considering: 
(1) Acoustic thresholds above which NMFS believes the best available 
science indicates marine mammals will be behaviorally harassed or incur 
some degree of permanent hearing impairment; (2) the area or volume of 
water that will be ensonified above these levels in a day; (3) the 
density or occurrence of marine mammals within these ensonified areas; 
and, (4) and the number of days of activities. Below, we describe these 
components in more detail and present the proposed take estimate.

Acoustic Thresholds

    Using the best available science, NMFS has developed acoustic 
thresholds that identify the received level of underwater sound above 
which exposed marine mammals would be reasonably expected to be 
behaviorally harassed (equated to Level B harassment) or to incur PTS 
of some degree (equated to Level A harassment).
    Level B Harassment for non-explosive sources--Though significantly 
driven by received level, the onset of behavioral disturbance from 
anthropogenic noise exposure is also informed to varying degrees by 
other factors related to the source (e.g., frequency, predictability, 
duty cycle), the environment (e.g., bathymetry), and the receiving 
animals (hearing, motivation, experience, demography, behavioral 
context) and can be difficult to predict (Southall et al., 2007, 
Ellison et al., 2011). Based on what the available science indicates 
and the practical need to use a threshold based on a factor that is 
both predictable and measurable for most activities, NMFS uses a 
generalized acoustic threshold based on received level to estimate the 
onset of behavioral harassment. NMFS predicts that marine mammals are 
likely to be behaviorally harassed in a manner we consider Level B 
harassment when exposed to underwater anthropogenic noise above 
received levels of 120 dB re 1 [mu]Pa (rms) for continuous (e.g. 
vibratory pile-driving, drilling) and above 160 dB re 1 [mu]Pa (rms) 
for non-explosive impulsive (e.g., seismic airguns) or intermittent 
(e.g., scientific sonar) sources. For in-air sounds, NMFS predicts that 
pinnipeds exposed above received levels of 100 dB re 20 [mu]Pa (rms) 
will be behaviorally harassed.
    Chevron's proposed activity includes the use of continuous 
(vibratory driving) and impulsive (impact driving) sources, and 
therefore the 120 and160 dB re 1 [mu]Pa (rms) are applicable.
    Level A harassment for non-explosive sources--NMFS' Technical 
Guidance for Assessing the Effects of Anthropogenic Sound on Marine 
Mammal Hearing (Technical Guidance, 2016) identifies dual criteria to 
assess auditory injury (Level A harassment) to five different marine 
mammal groups (based on hearing sensitivity) as a result of exposure to 
noise from two different types of sources (impulsive or non-impulsive). 
Applicant's proposed activity includes the use of impulsive (impact 
driving) and non-impulsive (vibratory driving) sources.
    These thresholds are provided in Table 4. The references, analysis, 
and methodology used in the development of the thresholds are described 
in NMFS 2016 Technical Guidance, which may be accessed at: http://www.nmfs.noaa.gov/pr/acoustics/guidelines.htm.

                     Table 4--Thresholds Identifying the Onset of Permanent Threshold Shift
----------------------------------------------------------------------------------------------------------------
                                                    PTS Onset acoustic thresholds *  (received level)
             Hearing group              ------------------------------------------------------------------------
                                                  Impulsive                         Non-impulsive
----------------------------------------------------------------------------------------------------------------
Low-Frequency (LF) Cetaceans...........  Cell 1: Lpk,flat: 219 dB;   Cell 2: LE,LF,24h: 199 dB.
                                          LE,LF,24h: 183 dB.
Mid-Frequency (MF) Cetaceans...........  Cell 3: Lpk,flat: 230 dB;   Cell 4: LE,MF,24h: 198 dB.
                                          LE,MF,24h: 185 dB.
High-Frequency (HF) Cetaceans..........  Cell 5: Lpk,flat: 202 dB;   Cell 6: LE,HF,24h: 173 dB.
                                          LE,HF,24h: 155 dB.
Phocid Pinnipeds (PW) (Underwater).....  Cell 7: Lpk,flat: 218 dB;   Cell 8: LE,PW,24h: 201 dB.
                                          LE,PW,24h: 185 dB.
Otariid Pinnipeds (OW) (Underwater)....  Cell 9: Lpk,flat: 232 dB;   Cell 10: LE,OW,24h: 219 dB.
                                          LE,OW,24h: 203 dB.
----------------------------------------------------------------------------------------------------------------
* Dual metric acoustic thresholds for impulsive sounds: Use whichever results in the largest isopleth for
  calculating PTS onset. If a non-impulsive sound has the potential of exceeding the peak sound pressure level
  thresholds associated with impulsive sounds, these thresholds should also be considered.
Note: Peak sound pressure (Lpk has a reference value of 1 [mu]Pa, and cumulative sound exposure level (LE) has a
  reference value of 1[mu]Pa2s. In this Table, thresholds are abbreviated to reflect American National Standards
  Institute standards (ANSI 2013). However, peak sound pressure is defined by ANSI as incorporating frequency
  weighting, which is not the intent for this Technical Guidance. Hence, the subscript ``flat'' is being
  included to indicate peak sound pressure should be flat weighted or unweighted within the generalized hearing
  range. The subscript associated with cumulative sound exposure level thresholds indicates the designated
  marine mammal auditory weighting function (LF, MF, and HF cetaceans, and PW and OW pinnipeds) and that the
  recommended accumulation period is 24 hours. The cumulative sound exposure level thresholds could be exceeded
  in a multitude of ways (i.e., varying exposure levels and durations, duty cycle). When possible, it is
  valuable for action proponents to indicate the conditions under which these acoustic thresholds will be
  exceeded.

Ensonified Area

    Here, we describe operational and environmental parameters of the 
activity that will feed into identifying the area ensonified above the 
acoustic thresholds.
    Pile driving will generate underwater noise that potentially could 
result in disturbance to marine mammals swimming by the project area. 
Transmission loss (TL) underwater is the decrease in acoustic intensity 
as an acoustic pressure wave propagates out from a source until the 
source becomes indistinguishable from ambient sound. TL parameters vary 
with frequency, temperature, sea conditions, current, source and 
receiver depth, water depth, water chemistry, and bottom composition 
and topography. A standard sound propagation model, the Practical 
Spreading Loss model, was used to estimate the range from pile driving 
activity to various expected SPLs at potential project structures. This 
model follows a geometric propagation loss based on the distance from 
the driven pile, resulting in a 4.5 dB reduction in level for each 
doubling of distance from the source. In this model, the SPL at some 
distance away from the source (e.g., driven pile) is governed by a 
measured source level, minus the TL of the energy as it dissipates with 
distance. The TL equation is:

TL = 15log10(R1/R2)

Where:

TL is the transmission loss in dB,

[[Page 18815]]

R1 is the distance of the modeled SPL from the driven 
pile, and
R2 is the distance from the driven pile of the initial 
measurement.

    The degree to which underwater noise propagates away from a noise 
source is dependent on a variety of factors, most notably by the water 
bathymetry and presence or absence of reflective or absorptive 
conditions including the sea surface and sediment type. The TL model 
described above was used to calculate the expected noise propagation 
from both impact and vibratory pile driving, using representative 
source levels to estimate the zone of influence (ZOI) or area exceeding 
specified noise criteria.

Source Levels

    Sound source levels from the Chevron site were not available. 
Therefore, literature values published for projects similar to the 
Chevron project were used to estimate source levels that could 
potentially be produced. Results are shown in Table 5.
    Modifications at the four berths require the placement of new 24-
inch diameter square concrete piles. Approximately one to two of these 
piles would be installed in one workday, using impact driving methods. 
Based on measured blow counts for 24-inch concrete piles driven at the 
Long Wharf Berth 4 in 2011, installation for each pile could require up 
to approximately 300 blows and 1.5 second per blow average over a 
duration of approximately 20 minutes per pile, with 40 minutes of pile 
driving time per day if two piles are installed. To estimate the noise 
effects of the 24-inch square concrete piles, the general values 
provided by Caltrans (2015a) are shown in Table 5.
    To estimate the noise effects of impact driving of 14-inch steel H 
piles, the values provided by Caltrans were also utilized. These source 
values are 208 dB peak, 187 RMS, and 177 dB SEL(single strike). Based 
on these levels, impact driving of the 14-inch steel H piles is 
expected to produce underwater sound exceeded the Level B 160 dB RMS 
threshold over a distance of 631 meters.
    During construction, temporary fendering would be installed at 
Berth 2 which will be supported by thirty-six steel 14-inch steel H 
piles. It is estimated that each pile could be driven in five (5) 
minutes. Two (2) to four (4) piles would be installed in any single 
workday for a total of approximately 12 days of installation. For the 
purposes of calculating the distance to Level A thresholds, four piles 
per day is assumed. The piles would be removed after the permanent 
fenders are in place. A vibratory hammer would be used to vibrate the 
piles to facilitate pulling them from the mud. The best match for 
estimated source levels is the Port of Anchorage pile driving test 
project. During vibratory pile driving associated with the Anchorage 
project, peak noise levels ranged from 165 to 175 dB, and the RMS 
ranged between 152 and 168 dB, both measured at approximately 15 meters 
(50 ft) (Caltrans 2015a).
    The source levels for vibratory installation of 36-inch temporary 
steel piles were from the Explosive Handling Wharf-2 (EHW-2) project 
located at the Naval Base Kitsap in Bangor, Washington as stated in 
Caltrans (2015a). During vibratory pile driving measured peak noise 
levels were approximately 180 dB, and the RMS was approximately 169 dB 
at a 10 meter (33ft) distance. These temporary piles would require a 
drive time per pile of approximately 10 minutes. Up to four (4) of 
these piles could be installed in any single workday for a total of 40 
minutes.
    The most applicable source values for wooden pile removal were 
derived from measurements taken at the Port Townsend dolphin pile 
removal in Washington. During vibratory pile extraction associated with 
this project, which occurred under similar circumstances, measured peak 
noise levels were approximately 164 dB, and the RMS was approximately 
150 dB (WSDOT 2011). Applicable sound values for the removal of 
concrete piles could not be located, but they are expected to be 
similar to the levels produced by wooden piles described above, as they 
are similarly sized, non-metallic, and will be removed using the same 
methods.
    During construction, 106 16-inch timber piles, and seven 18 to 24-
inch square concrete piles would be removed. Up to twelve of these 
piles could be extracted in one workday. Extraction time needed for 
each pile may vary greatly, but could require approximately 400 seconds 
(approximately 7 minutes).

 Table 5--The Sound Levels (dB Peak, dB RMS, and dB sSEL) Expected To Be Generated by Each Hammer and Pile Type
----------------------------------------------------------------------------------------------------------------
                                                                    Estimated       Estimated       Estimated
                                                                    pressure        pressure      single strike
             Type of pile                     Hammer type          level  (dB      Level  (dB     sound exposure
                                                                      Peak)           RMS)       level (dB sSEL)
----------------------------------------------------------------------------------------------------------------
24-inch sq. concrete.................  Impact..................             188             176              166
14-inch Temporary steel H-pile.......  Impact..................             208             187              177
14-inch Temporary steel H-pile.......  Vibratory...............             180            *168  ...............
36-inch Steel Pipe...................  Vibratory...............             180             169  ...............
Wood and concrete pile extraction....  Vibratory...............             164             150  ...............
----------------------------------------------------------------------------------------------------------------
*Measured at 15 m.

    When NMFS Technical Guidance (2016) was published, in recognition 
of the fact that ensonified area/volume could be more technically 
challenging to predict because of the duration component in the new 
thresholds, we developed a User Spreadsheet that includes tools to help 
predict a simple isopleth that can be used in conjunction with marine 
mammal density or occurrence to help predict takes. We note that 
because of some of the assumptions included in the methods used for 
these tools, we anticipate that isopleths produced are typically going 
to be overestimates of some degree, which will result in some degree of 
overestimate of Level A take. However, these tools offer the best way 
to predict appropriate isopleths when more sophisticated 3D modeling 
methods are not available, and NMFS continues to develop ways to 
quantitatively refine these tools, and will qualitatively address the 
output where appropriate. For stationary sources NMFS User Spreadsheet 
predicts the closest distance at which, if a marine mammal remained at 
that distance the whole duration of the activity, it would not

[[Page 18816]]

incur PTS. Inputs used in the User Spreadsheet, and the resulting 
isopleths are reported below.
    Table 6 shows the inputs that were used in the User Spreadsheet to 
determine cumulative PTS Thresholds. Table 7 shows the Level A 
Isopleths as determined utilizing inputs from Table 6. Level B 
isopleths for impact and vibratory driving and extraction are shown in 
Table 8.

                                                          Table 6--Inputs for User Spreadsheet
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                        E.1: Impact pile        E.1: Impact pile
                                       driving (stationary     driving (stationary   A: Stationary source:  A: Stationary source:  A: Stationary source:
        Spreadsheet tab used           source: impulsive,      source: impulsive,        non-impulsive,         non-impulsive,         non-impulsive,
                                          intermittent)           intermittent)            continuous             continuous             continuous
--------------------------------------------------------------------------------------------------------------------------------------------------------
Pile Type and Hammer Type..........  24-inch sq. concrete    14-inch Steel H pile..  14-inch Steel H pile.  36-in steel..........  Wood concrete pile
                                      piles.                                                                                        extraction.
Source Level.......................  166 (Single strike/     177 (Single strike/     168 RMS..............  169 RMS..............  150 RMS.
                                      shot SEL).              shot SEL).
Weighting Factor Adjustment (kHz)..  2.....................  2.....................  2.5..................  2.5..................  2.5.
Number of strikes in 1-h OR number   300...................  200...................  NA...................  NA...................  NA.
 of strikes per pile.
Activity Duration (h) within 24-h    2 piles...............  4 piles...............  0.333................  0.6667...............  1.333.
 period OR number of piles per day.
Propagation (xLogR)................  15....................  15....................  15...................  15...................  15.
Distance of source level             10....................  10....................  15...................  10...................  10.
 measurement (meters);.
--------------------------------------------------------------------------------------------------------------------------------------------------------


                Table 7--Radial Distances to Level A Isopleth During Impact and Vibratory Driving
----------------------------------------------------------------------------------------------------------------
                                                            Distance in meters  (feet)
                                 -------------------------------------------------------------------------------
 Project element requiring pile                                        High-
          installation            Low- frequency  Mid- frequency     frequency        Phocid          Otariid
                                     cetaceans       cetaceans       cetaceans       pinnipeds       pinnipeds
----------------------------------------------------------------------------------------------------------------
Impact Driving:
    24 inch square concrete (1-2        52 (171)           2 (6)        62 (204)         28 (92)           2 (7)
     per day)...................
    14-inch steel H pile (4 per      343 (1,124)         12 (40)     408 (1,339)       183 (602)         13 (44)
     day).......................
Vibratory Driving/Extraction:
    14-inch steel H pile (4 per          14 (46)           1 (3)         21 (69)          9 (30)           1 (3)
     day).......................
    36-inch steel pipe pile (4           18 (58)           2 (5)         26 (86)         11 (35)           1 (2)
     per day)...................
    Wood and concrete pile                 2 (5)           0 (0)           2 (7)           1 (3)           0 (0)
     extraction (12 per day)....
----------------------------------------------------------------------------------------------------------------


    Table 8--Radial Distances to Level B Isopleths During Impact and
                            Vibratory Driving
------------------------------------------------------------------------
                                                          Distance to
                      Pile type                           threshold in
                                                         meters  (feet)
------------------------------------------------------------------------
Impact Driving (160 dB threshold):
    24[dash]inch square concrete.....................          117 (382)
    14-inch steel H pile.............................        631 (2,070)
Vibratory Driving/Extraction (120 dB threshold):
    14-inch steel H pile.............................    23,773 (77,995)
    36-inch steel pipe pile..........................    18,478 (60,609)
    Wood and concrete pile extraction................      1,000 (3,280)
------------------------------------------------------------------------

Marine Mammal Occurrence

    In this section we provide the information about the presence, 
density, or group dynamics of marine mammals that will inform the take 
calculations.
    San Francisco Bay has five known harbor seal haul out sites that 
include Alcatraz Island, Castro Rocks, Yerba Buena Island, Newark 
Slough, and Mowry Slough. Yerba Buena Island, Alcatraz and Castro Rocks 
are within or near the areas within ensonified Level B zones. Castro 
Rocks is the largest harbor seal haul out site in the northern part of 
San Francisco Bay and is the second largest pupping site in the Bay 
(Green et al. 2002). The pupping season is from March to June in San 
Francisco Bay. During the molting season (typically June-July and 
coincides with the period when piles will be driven) as many as 
approximately 130 harbor seals on average have been observed using 
Castro Rocks as a haul out. Harbor seals are more likely to be hauled 
out in the late afternoon and evening, and are more likely to be in the 
water during the morning and early afternoon (Green et al. 2002). 
However, during the molting season, harbor seals spend more time hauled 
out and tend to enter the water later in the evening. During molting, 
harbor seals can stay onshore resting for an average of 12 hours per 
day during the molt compared to around 7 hours per day outside of the 
pupping/molting seasons (NPS 2014). Tidal stage is a major controlling 
factor of haul out usage at Castro Rocks with more seals present during 
low tides than high tide periods (Green et al. 2002). Additionally, the 
number of seals

[[Page 18817]]

hauled out at Castro Rocks also varies with the time of day, with 
proportionally more animals hauled out during the nighttime hours 
(Green et al. 2002). Therefore, the number of harbor seals in the water 
around Castro Rocks will vary throughout the work period. The number of 
harbor seals located at Castro Rocks is based on the highest mean plus 
the standard error of harbor seals observed at Castro Rocks during 
recent annual surveys conducted by the National Park Service (NPS) 
(Codde, S. and S. Allen 2013, 2015, and 2017), resulting in a value of 
176 seals. The same NPS survey determined that harbor seal population 
in the Central Bay at Alcatraz and Yerba Buena Island is approximately 
167 seals (Codde, S. and S. Allen 2013, 2015, and 2017).
    California sea lions haul out primarily on floating docks at Pier 
39 in the Fisherman's Wharf area of the San Francisco Marina, 
approximately 12.5 km (7.8 miles) southwest of the project area. Based 
on counts done in 1997 and 1998, the number of California sea lions 
that haul out at Pier 39 fluctuates with the highest occurrences in 
August and the lowest in June. In addition to the Pier 39 haulout, 
California sea lions haul out on buoys and similar structures 
throughout the Bay. They are seen swimming off mainly the San Francisco 
and Marin shorelines within the Bay but may occasionally enter the 
project area to forage. Over the monitoring period for the RSRB, 
monitors sighted at least 90 California sea lions in the North Bay and 
at least 57 in the Central Bay (Caltrans 2012). During monitoring for 
the San Francisco-Oakland Bay Bridge (SFOBB) Project in the central 
Bay, 69 California sea lions were observed in the vicinity of the 
bridge over a 17-year period from 2000-2017 (Caltrans 2018), and from 
these observations, an estimated density of 0.161 animals per square 
kilometer (km\2\) is derived (NMFS 2018).
    A small but growing population of harbor porpoises utilizes San 
Francisco Bay. Harbor porpoises are typically spotted in the vicinity 
of Angel Island and the Golden Gate (6 and 12 km southwest 
respectively) with lesser numbers sighted in the vicinity of Alcatraz 
and around Treasure Island (Keener 2011). Porpoises but may utilize 
other areas in the Central Bay in low numbers, including the proposed 
project area. However, harbor porpoise are naturally inclined to remain 
near the shoreline areas and downstream of large landmasses as they are 
constantly foraging. For this reason, the project area would present a 
less than likely area to observe harbor porpoise as they would either 
need to traverse the perimeter of the Bay to arrive there, or would 
have to swim through the open Bay. Both scenarios are possible, but 
would represent uncmmon behavior. Based on monitoring conducted for the 
SFOBB project, between 2000-2017 an in-water density of 0.031 animals 
per km\2\ estimated by Caltrans for this species. However, porpoise 
occurrence increased significantly in 2017 resulting in a 2017 only 
density of 0.167 animals per km\2\ (Caltrans 2018).
    Small numbers of northern elephant seals haul out or strand on 
coastline within the Central Bay. Monitoring of marine mammals in the 
vicinity of the SFOBB has been ongoing for 15 years; from those data, 
Caltrans has produced an estimated at-sea density for northern elephant 
seal of 0.06 animal per km\2\ (Caltrans, 2015b). Most sightings of 
northern elephant seal in San Francisco Bay occur in spring or early 
summer, and are less likely to occur during the periods of in-water 
work for this project. As a result, densities during pile driving for 
the proposed action would be much lower.
    The incidence of northern fur seal in San Francisco Bay depends 
largely on oceanic conditions, with animals more likely to strand 
during El Ni[ntilde]o events. The likelihood of El Ni[ntilde]o 
conditions occurring in 2018 is currently low, with La Ni[ntilde]a or 
neutral conditions expected to develop (NOAA, 2018).
    The range of the bottlenose dolphin has expanded northward along 
the Pacific Coast since the 1982-1983 El Ni[ntilde]o (Carretta et al. 
2013, Wells and Baldridge 1990). They now occur as far north as the San 
Francisco Bay region and have been observed along the coast in Half 
Moon Bay, San Mateo, Ocean Beach in San Francisco, and Rodeo Beach in 
Marin County. Observations indicate that bottlenose dolphin 
occasionally enter San Francisco Bay, sometimes foraging for fish in 
Fort Point Cove, just east of the Golden Gate Bridge (Golden Gate 
Cetacean Research 2014). Transient individuals of this species 
occasionally enter San Francisco Bay, but observations indicate that 
they usually remain in proximity to the Golden Gate near the mouth of 
the Bay. Beginning in 2015, two individuals have been observed 
frequently in the vicinity of Oyster Point, located south of San 
Francisco (GGCR, 2016; GGCR 2017; Perlman, 2017). Bottlenose dolphins 
are being observed in San Francisco Bay more frequently in recent 
years. Groups with an average size of five animals have been observed 
entering the Bay in the vicinity of Yerba Buena Island at a rate of 
once per week. They usually are observed over two week spans and then 
depart for an extended period of time. (NMFS, 2017b).
    Gray whales occasionally enter the Bay during their northward 
migration period, and are most often sighted in the Bay between 
February and May. Most venture only about 2 to 3 km (about 1-2 miles) 
past the Golden Gate, but gray whales have occasionally been sighted as 
far north as San Pablo Bay. Pile driving is not expected to occur 
during this time, and gray whales are not likely to be present at other 
times of year.

Take Calculation and Estimation

    Here we describe how the information provided above is brought 
together to produce a quantitative take estimate.
    The following assumptions are made when estimating potential 
incidences of take:
     All marine mammal individuals potentially available are 
assumed to be present within the relevant area, and thus incidentally 
taken;
     An individual can only be taken once during a 24-h period;
     Exposures to sound levels at or above the relevant 
thresholds equate to take, as defined by the MMPA.
    Limited density data is available for marine mammal species in San 
Francisco Bay. Estimates here are determined using data taken during 
marine mammal monitoring associated with RSRB retrofit project, the San 
Francisco-Oakland Bay Bridge replacement project, and other marine 
mammal observations for San Francisco Bay. For Pacific harbor seal, 
data was also derived from recent annual surveys of haul outs in the 
Bay conducted by the National Park Service (Codde, S. and S. Allen. 
2013, 2015, and 2017).

Pacific Harbor Seal

    As noted above, take estimates are based on the highest mean plus 
the standard error of harbor seals observed by NPS at Castro Rocks 
which equals 176 animals. (Codde, S. and S. Allen. 2013, 2015, and 
2017) Since pile driving would occur intermittently during the day, 
varying sets of animals may be hauled out or in the water. For 
simplicity, this analysis assumes that since harbor seals haul out for 
around 7 hours when not pupping/molting, 7/24 or 29 percent of the 
harbor seals would not be in the water during pile driving and would 
not be exposed. Thus, it is estimated that 71 percent of the 176 
individuals (125 individuals) will be in the water at some point during 
each work day, and potentially exposed to underwater noise from pile 
driving. Of these 125 seals, the proportion that may enter the areas 
over which the Level B harassment

[[Page 18818]]

thresholds may be exceeded are estimated as follows:
     Impact driving of 24-inch concrete piles at all Berths: It 
is assumed that 10 percent of the animals that enter the water from 
Castro Rocks will enter the small Level B zones associated with this 
pile type as shown in Figure 6-1 in the application. Thus, it is 
estimated that up to 12.5 individuals per day could be exposed (125/10 
= 12.5) by entering the Level B harassment zone to the south of Castro 
Rocks.
     Impact driving of 14-inch steel H piles: Impact driving 
would only occur in the event that a pile encounters an obstruction 
such as an old timber pile beneath the mud line. These piles will be 
preferentially driven with a vibratory driver, which would have a 
larger Level B zone but a smaller Level A zone than installation with 
an impact driver. Thus, Level B take for this activity is based on 
installation using vibratory driver, while Level A take is based on 
installation using impact driving. For the purposes of calculating 
Level A take, as a proportion of Level B take, it is assumed that 
approximately 25 percent of the 125 harbor seals using Castro Rocks 
could approach and be subject to Level B harassment due to the size and 
location of the Level B isopleth (Figure 6-2 in application). 
Therefore, it is assumed that up to 31.25 individuals per day could be 
exposed when this activity is being conducted.
     Vibratory driving and removal of the 36-inch steel pipe 
piles at Berth 4: Isopleths for this vibratory driving encompass Castro 
Rocks, therefore it is assumed that all of the estimated 125 animals in 
the water, could be exposed when these piles are being driven at Berth 
4.
     Vibratory driving/extraction of the 14-inch H piles at 
Berth 2: Isopleths for this vibratory driving encompass Castro Rocks, 
therefore is assumed that all of the 125 animals in the water could be 
exposed when this activity is being conducted at Berth 2.
     Vibratory removal of timber and concrete piles at Berths 
1, 2 and 4: Due to the small size of the Level B zone for this 
activity, fewer harbor seals are expected to be exposed to Level B 
harassment. It is assumed that approximately 25 percent of the 125 
harbor seals using Castro Rocks could approach and be subject to Level 
B harassment. Therefore, it is assumed that up to 31.25 individuals per 
day could be exposed when this activity is being conducted.
    In order to account for other individuals that may be foraging in 
the more distant part of the Level B harassment zone, additional take 
of harbor seal has been estimated based on other harbor seal 
populations in the Central Bay. Using the same data set (Codde, S. and 
S. Allen. 2013, 2015, and 2017) that was used for Castro Rocks, a 
population for the Central Bay of 167 harbor seals was established 
based on other Central Bay haulouts at Alcatraz and Yerba Buena Island. 
The area of the Central Bay (bound by the Golden Gate, Richmond Bridge, 
SFOBB, and adjoining coastline) is approximately 134 km\2\, resulting 
in a harbor seal density of 1.25 animals per km\2\. The population that 
hauls out at Castro Rocks is not included in this density estimate 
because of the proximity of the haul site to the project and potential 
take of those harbor seals has been estimated separately using the 
methods described above. The estimated take based on the Central Bay 
density is added to the take estimated for the Castro Rocks population, 
as provided in Table 9 below. Also provided in Table 9 is the estimated 
Level A take for impact driving of the steel 14-inch H piles, which has 
been estimated by taking Level B take and multiplying it by the ratio 
of the Level A zone area to the Level B zone area as requested by NMFS. 
Level A take is not requested for vibratory driving.

                                     Table 9--Daily Level A and Level B Harassment Estimate for Pacific Harbor Seal
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                  Estimated Level B take per day
                                                         --------------------------------------------------------------------------------
                                                                           Level A zone,                                                     Estimated
                        Pile type                          Level B zone        minus        Central bay       Project      Harbor seal--   Level A take
                                                              (km\2\)     exclusion zone  \1\  (1.25 per   vicinity \1\        total      per day--total
                                                                              (km\2\)         km\2\)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vibratory Driving:
    14-inch steel H pile................................          192.31              NA          239.55             125          364.55              NA
    36-inch steel pile..................................          176.44              NA          219.76             125          344.76              NA
    Timber/Concrete Pile Removal........................            3.69              NA            4.59           31.25           35.84              NA
Impact Driving:
    14-inch steel H pile................................            1.36            0.10          * 1.69         * 31.25         * 32.88            2.47
    24-inch concrete pile...............................            0.04               0            0.05            12.5           12.55               0
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Based on 71 percent of 176 individuals that haul out at Castro Rocks, approximately 1,000 m from project site.
* Only displayed to provide the calculation of Level A take. Level B take authorized for vibratory driving would cover any level B take from occasional
  impact driving.

    For impact pile driving of the 14-inch steel H piles, the PTS Zone 
is large enough to warrant a smaller exclusion zone and the 
authorization of some Level A harassment for harbor seal so that pile 
driving can be completed on schedule. A 35 meter shutdown zone (smaller 
than the Level A Zone) for this species would be established, but 
individuals that place themselves in the Level A zone but outside of 
the shut-down zone may experience Level A harassment, if they reside in 
that area for a long enough duration.

California Sea Lion

    The estimated California seal lion density of 0.16 animals per 
km\2\ previously described was used to calculate potential Level B 
exposures as shown in Table 10.

[[Page 18819]]



 Table 10--Daily Level B Harassment Exposure Estimate for California Sea
                                  Lion
------------------------------------------------------------------------
                                                           Level B Take
                                                             estimate
                                                             (based on
                Pile type                  Level B zone     Central Bay
                                              (km\2\)       density  of
                                                           0.16  animals
                                                            per km\2\)
------------------------------------------------------------------------
Vibratory Driving:
  14-inch steel H pile..................          192.31           17.30
  36-inch steel pile....................          176.44           15.88
  Timber/Concrete Pile Removal..........            3.69            0.33
Impact Driving:
  14-inch steel H pile..................              NA              NA
  24-inch concrete pile.................            0.17            0.02
------------------------------------------------------------------------

Harbor Porpoise

    Based on monitoring conducted for the SFOBB project described 
previously, an in-water density of 0.17 animals per km\2\ was estimated 
by Caltrans for this species (NMFS 2017b). Using this in-water density 
and the areas of potential harassment, take is estimated for harbor 
porpoise as provided in Table 11. Also provided in Table 11 is the 
estimated Level A take for impact driving, which has been estimated by 
taking Level B take and multiplying it by the ratio of the Level A zone 
area to the Level B zone area. A single harbor porpoise could be 
exposed to Level A harassment during impact driving or 14-inch steel H-
piles as shown in Table 13. NMFS, however, conservatively proposes to 
authorize Level A take of two animals.

               Table 11--Daily Level A and Level B Harassment Estimate for Pacific Harbor Porpoise
----------------------------------------------------------------------------------------------------------------
                                                                                      Level B
                                                                   Level A zone,     estimate        Estimated
                    Pile type                      Level B zone        minus      central bay in-  Level A take
                                                      (km\2\)     exclusion zone   water-- 0.17       per day
                                                                      (km\2\)        per km\2\
----------------------------------------------------------------------------------------------------------------
Vibratory Driving:
    14-inch steel H pile........................          192.31  ..............           32.69              NA
    36-inch steel pile..........................          176.44  ..............           29.99              NA
    Timber/Concrete Pile Removal................            3.69  ..............            0.63              NA
Impact Driving:
    14-inch steel H pile........................            1.36          * 0.32          * 0.23            0.05
    24-inch concrete pile.......................            0.04               0            0.04               0
----------------------------------------------------------------------------------------------------------------
* Only displayed to provide the calculation of Level A take. Level B take authorized for vibratory driving would
  cover any Level B take from occasional impact driving.

    For impact pile driving of the 14-inch H piles, the Level A Zone is 
large enough to warrant the authorization of some Level A. A 250 meter 
shutdown zone for this species would be established, but individuals 
that place themselves in the Level A zone but outside of the shut-down 
zone may experience Level A harassment, if they reside in that area for 
a long enough duration.

Northern Elephant Seal

    Monitoring of marine mammals in the vicinity of the SFOBB has been 
ongoing for produced an estimated density for northern elephant seal of 
0.06 animal per km\2\ (Caltrans, 2015b). Most sightings of northern 
elephant seal in San Francisco Bay occur in spring or early summer, and 
are less likely to occur during the periods of in-water work for this 
project. As a result, densities during pile driving for the proposed 
action would be much lower. It is possible that a lone northern 
elephant seal may enter the Level B harassment area once per day during 
pile driving, for a total of 28 takes. Level A harassment of this 
species is not expected to occur and is not proposed by NMFS.

Northern Fur Seal

    As noted previously, the incidence of northern fur seal in San 
Francisco Bay depends largely on oceanic conditions, with animals more 
likely to strand during El Ni[ntilde]o events. The likelihood of El 
Ni[ntilde]o conditions occurring in 2018 is currently low, with La 
Ni[ntilde]a or neutral conditions expected to develop (NOAA, 2018). 
Given the low probability that fur seals would enter into the Bay and 
project area in 2018, Chevron has conservatively requested and NMFS is 
proposing authorization of 10 fur seals takes by Level B harassment. 
Level A harassment of this species is not anticipated or authorized by 
NMFS.

Bottlenose Dolphin

    When this species is present in San Francisco Bay, it is more 
typically found close to the Golden Gate. Recently, beginning in 2015, 
two individuals have been observed frequently in the vicinity of Oyster 
Point (GGCR, 2016; GGCR 2017; Perlman, 2017). The average reported 
group size for bottlenose dolphins is five. Reports show that a group 
normally comes into San Francisco Bay near Yerba Buena Island once per 
week for approximately 2-week stints and then leaves the Bay (NMFS, 
2017b). Chevron assumed groups of five individuals may enter San 
Francisco Bay and the ensonified area three times during separate two-
week spans. Therefore, groups of 5 animals would potentially be exposed 
at a rate of once per week over six weeks, resulting in up

[[Page 18820]]

to 30 Level B exposures. As such, NMFS proposes to authorize the take 
by Level B harassment of 30 bottlenose dolphins. Although a small Level 
A zone for mid-frequency cetaceans is estimated during impact driving, 
marine mammal monitoring of the shutdown would ensure that take by 
Level A harassment does not occur.

Gray Whale

    Gray whales are the only whale species that travels far into San 
Francisco Bay with any regularity. They occasionally enter the Bay 
during their northward migration period, and are most often sighted in 
the Bay between February and May. Most venture only about 2 to 3 
kilometers (about 1-2 miles) past the Golden Gate, but gray whales have 
occasionally been sighted as far north as San Pablo Bay. Pile driving 
is not anticipated to occur during the February through May timeframe 
and gray whales are not likely to be present at other times of year. In 
the very unlikely event that a gray whale or pair of gray whales makes 
its way close to the project area while pile driving activities are 
under way, Chevron has requested take by Level B harassment of up to 
two (2) gray whales per year. NMFS agrees and proposes the take of 2 
gray whales by Level B harassment. No Level A take is proposed.
    Tables 12 and 13 summarize the estimate of Level B and Level A 
harassment, respectively, for each species by pile driving activity for 
the 2018 construction season. For harbor seals, sea lions, harbor 
porpoise and elephant seals, the Level B harassment estimates are based 
on the number of individuals assumed to be exposed per day, the number 
of days of pile driving expected based on an average installation rate. 
The Level A harassment estimates are derived from the Level B 
harassment estimates by taking the Level B harassment and multiplying 
it by the fractional ratio of the area of the Level A zone to the Level 
B zone.

                                      Table 12--Total Estimated Take by Level B Harassment by Species and Pile Type
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                             Species
                                                              Number of --------------------------------------------------------------------------------
           Pile type             Pile driver type  Number of   driving                           Harbor
                                                     piles       days      Harbor     CA sea    porpoise     Gray    N. elephant    N. fur    Bottlenose
                                                                            seal       lion        *       whale *       seal        seal      dolphin
--------------------------------------------------------------------------------------------------------------------------------------------------------
36-inch steel template pile**.  Vibratory........          8          2     689.01      56.46      58.93         NA            2         NA           NA
Concrete pile removal.........  Vibratory........          5          1      35.78       0.59       0.62         NA            1         NA           NA
24-inch concrete..............  Impact...........          8          8     100.23       0.06       0.06         NA            8         NA           NA
14-inch H pile installation***  Impact/Vibratory.         36         12   4,371.28     369.24     385.39         NA           12         NA           NA
Timber pile removal...........  Vibratory........         53          5     178.89       2.95       3.08         NA            5         NA           NA
                                                  ------------------------------------------------------------------------------------------------------
    Total take by species       .................  .........  .........      5,375        429        448          2           28         10           30
     (2018).
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Take is not calculated by activity type for these species, only a total is given.
** Only the installation of the template piles will occur in 2018. Take associated with their removal will be requested in a subsequent IHA.
*** These piles will be preferentially driven with a vibratory driver, which would have a larger Level B zone than installation with an impact driver.
  Thus, Level B take for this species is based on installation using vibratory driver, and not an impact driver.


                                  Table 13--Proposed Take by Level A Harassment
----------------------------------------------------------------------------------------------------------------
                                                                     Number of                        Harbor
               Pile type                    Pile driver type       driving days    Harbor  seal      porpoise
----------------------------------------------------------------------------------------------------------------
36-inch steel template pile...........  Vibratory...............               2               0               0
Concrete pile removal.................  Vibratory...............               1               0               0
24-inch concrete......................  Impact..................               8               0               0
14-inch H pile installation...........  Impact/Vibratory........              12              29            0.65
Timber pile removal...................  Vibratory...............               5               0               0
                                                                 -----------------------------------------------
    Total take........................  ........................  ..............              29               1
----------------------------------------------------------------------------------------------------------------

    Table 14 provides a summary of proposed authorized Level A and 
Level B takes as well as the percentage of a stock or population 
proposed for take.

                    Table 14--Proposed Authorized Take and Percentage of Stock or Population
----------------------------------------------------------------------------------------------------------------
                                                                     Proposed        Proposed
                Species                           Stock             authorized      authorized        Percent
                                                                  Level A  takes  Level B  takes    population
----------------------------------------------------------------------------------------------------------------
Harbor seal...........................  California..............              29           5,375            17.4
California sea lion...................  Eastern U.S.............  ..............             429           <0.01
Harbor porpoise.......................  San Francisco-Russian                  2             448             4.5
                                         River.
Northern elephant seal................  California Breeding.....  ..............              28           <0.01
Gray whale............................  Eastern North Pacific...  ..............               2           <0.01
Northern fur seal.....................  California..............  ..............              10           <0.01
Bottlenose Dolphin....................  California Coastal......  ..............              30             6.6
----------------------------------------------------------------------------------------------------------------


[[Page 18821]]

Proposed Mitigation

    In order to issue an IHA under Section 101(a)(5)(D) of the MMPA, 
NMFS must set forth the permissible methods of taking pursuant to such 
activity, and other means of effecting the least practicable 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 (latter 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 consider 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. 
This considers the nature of the potential adverse impact being 
mitigated (likelihood, scope, range). It further considers the 
likelihood that the measure will be effective if implemented 
(probability of accomplishing the mitigating result if implemented as 
planned) the likelihood of effective implementation (probability 
implemented as planned) and;
    (2) the practicability of the measures for applicant 
implementation, which may consider such things as cost, impact on 
operations, and, in the case of a military readiness activity, 
personnel safety, practicality of implementation, and impact on the 
effectiveness of the military readiness activity.

Mitigation for Marine Mammals and Their Habitat

    The following measures would apply to Chevron's mitigation 
requirements:
     Seasonal Restriction--To minimize impacts to listed fish 
species, pile-driving activities would occur between June 1 and 
November 30.
     Daylight Construction Period--Work would occur only during 
daylight hours (7:00 a.m. to 7:00 p.m.) when visual marine mammal 
monitoring can be conducted.
     Establishment of Shutdown Zone--For all pile driving/
removal and drilling activities, Chevron will establish a shutdown 
zone. The purpose of a shutdown zone is generally to define an area 
within which shutdown of activity would occur upon sighting of a marine 
mammal (or in anticipation of an animal entering the defined area). A 
shutdown zone will be established which will include all or a portion 
of the area where underwater SPLs are expected to reach or exceed the 
cumulative SEL thresholds for Level A harassment as provided in Table 
7. The shutdown isopleths for pinnipeds (harbor seals, California sea 
lion, Northern elephant seal, northern fur seal) and mid-frequency 
cetaceans (common dolphins) will be set at 35 meters; for high-
frequency cetaceans (harbor porpoises) at 250 meters; and for low-
frequency cetaceans (gray whales) at 350 meters.
     10-Meter Shutdown Zone--During the in-water operation of 
heavy machinery (e.g., barge movements), a 10-m shutdown zone for all 
marine mammals will be implemented. If a marine mammal comes within 10 
m, operations shall cease and vessels shall reduce speed to the minimum 
level required to maintain steerage and safe working conditions.
     Establishment of Monitoring Zones for Level A and Level 
B--Chevron will establish and monitor Level A harassment zones during 
impact driving for harbor seal extending to 183 meters and harbor seals 
and extending to 408 m for harbor porpoises. These are areas beyond the 
shutdown zone in which animals could be exposed to sound levels that 
could result in PTS. Chevron will also establish and monitor Level B 
harassment zones which are areas where SPLs are equal to or exceed the 
160 dB rms threshold for impact driving and the 120 dB rms threshold 
during vibratory driving and extraction. Monitoring zones provide 
utility for observing by establishing monitoring protocols for areas 
adjacent to the shutdown zones. Monitoring zones enable observers to be 
aware of and communicate the presence of marine mammals in the project 
area outside the shutdown zone and thus prepare for a potential cease 
of activity should the animal enter the shutdown zone. The Level B 
zones are depicted in Table 8. As shown, the largest Level B zone is 
equal to 192.31 km\2\, making it impossible for Protected Species 
Observers (PSOs) to view the entire harassment area. Due to this, Level 
B exposures will be recorded and extrapolated based upon the number of 
observed take and the percentage of the Level B zone that was not 
visible.
     Soft Start--The use of a soft-start procedure are believed 
to provide additional protection to marine mammals by providing warning 
and/or giving marine mammals a chance to leave the area prior to the 
hammer operating at full capacity. Chevron shall use soft start 
techniques when impact pile driving. Soft start requires contractors to 
provide an initial set of strikes at reduced energy, followed by a 
thirty-second waiting period, then two subsequent reduced energy strike 
sets.
     Pile Caps/Cushions--Chevron will employ the use of pile 
caps or cushions as sound attenuation devices to reduce impacts from 
sound exposure during impact pile driving.
     Pre-Activity Monitoring--Pre-activity monitoring shall 
take place from 30 minutes prior to initiation of pile driving activity 
and post-activity monitoring shall continue through 30 minutes post-
completion of pile driving activity. Pile driving may commence at the 
end of the 30-minute pre-activity monitoring period, provided observers 
have determined that the shutdown zone is clear of marine mammals, 
which includes delaying start of pile driving activities if a marine 
mammal is sighted in the zone, as described below.
     If a marine mammal approaches or enters the shutdown zone 
during activities or pre-activity monitoring, all pile driving 
activities at that location shall be halted or delayed, respectively. 
If pile driving is halted or delayed due to the presence of a marine 
mammal, the activity may not resume or commence until either the animal 
has voluntarily left and been visually confirmed beyond the shutdown 
zone and 15 minutes have passed without re-detection of the animal. 
Pile driving activities include the time to install or remove a single 
pile or series of piles, as long as the time elapsed between uses of 
the pile driving equipment is no more than thirty minutes.
     Non-authorized Take Prohibited--If a species for which 
authorization has not been granted or a species for which authorization 
has been granted but the authorized takes are met, is observed 
approaching or within the monitoring zone, pile driving and removal 
activities must shut down immediately using delay and shut-down 
procedures. Activities must not resume until the animal has been 
confirmed to have left the area or an observation time period of 15 
minutes has elapsed.
    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 
effecting the least

[[Page 18822]]

practicable impact on the affected 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 
authorizations must include the suggested means of accomplishing the 
necessary monitoring and reporting that will result in increased 
knowledge of the species and of the level of taking or impacts on 
populations of marine mammals that are expected to be present in the 
proposed action area. Effective reporting is critical both to 
compliance as well as ensuring that the most value is obtained from the 
required monitoring.
    Monitoring and reporting requirements prescribed by NMFS should 
contribute to improved understanding of one or more of the following:
     Occurrence of marine mammal species or stocks in the area 
in which take is anticipated (e.g., presence, abundance, 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 mammals; or (2) 
populations, species, or stocks;
     Effects on marine mammal habitat (e.g., marine mammal prey 
species, acoustic habitat, or other important physical components of 
marine mammal habitat); and
     Mitigation and monitoring effectiveness.

Visual Monitoring

    The following visual monitoring measures are proposed in the IHA.
     Biological monitoring would occur within one week before 
the Project's start date, to establish baseline observations.
     Monitoring distances, in accordance with the identified 
shutdown, Level A, and Level B zones, will be determined by using a 
range finder, scope, hand-held global positioning system (GPS) device 
or landmarks with known distances from the monitoring positions.
     Monitoring locations will be established at locations 
offering best views of the monitoring zone.
     Monitoring will be continuous unless the contractor takes 
a break longer than 2 hours from active pile and sheet pile driving, in 
which case, monitoring will be required 30 minutes prior to restarting 
pile installation.
     For in-water pile driving, under conditions of fog or poor 
visibility that might obscure the presence of a marine mammal within 
the shutdown zone, the pile in progress will be completed and then pile 
driving suspended until visibility conditions improve.
     At least two PSOs will be actively scanning the monitoring 
zone during all pile driving activities.
     Monitoring of pile driving shall be conducted by qualified 
PSOs (see below), who shall have no other assigned tasks during 
monitoring periods. Chevron shall adhere to the following conditions 
when selecting observers:
    (1) Independent PSOs shall be used (i.e., not construction 
personnel);
    (2) At least one PSO must have prior experience working as a marine 
mammal observer during construction activities;
    (3) Other PSOs may substitute education (degree in biological 
science or related field) or training for experience; and
    (4) Chevron shall submit PSO CVs for approval by NMFS.
     Chevron will ensure that observers have the following 
additional qualifications:
    (1) Ability to conduct field observations and collect data 
according to assigned protocols.
    (2) Experience or training in the field identification of marine 
mammals, including the identification of behaviors;
    (3) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    (4) Writing skills sufficient to prepare a report of observations 
including but not limited to the number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates, times, and reason for implementation of mitigation 
(or why mitigation was not implemented when required); and marine 
mammal behavior; and
    (5) Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time information on marine mammals 
observed in the area as necessary.
    A draft marine mammal monitoring report would be submitted to NMFS 
within 90 days after the completion of pile driving and removal 
activities. It will include an overall description of work completed, a 
narrative regarding marine mammal sightings, and associated marine 
mammal observation data sheets. Specifically, the report must include:
     Date and time that monitored activity begins or ends;
     Construction activities occurring during each observation 
period;
     Deviation from initial proposal in pile numbers, pile 
types, average driving times, etc.
     Weather parameters (e.g., percent cover, visibility);
     Water conditions (e.g., sea state, tide state);
     For each marine mammal sighting the following must be 
recorded:
    (1) Species, numbers, and, if possible, sex and age class of marine 
mammals;
    (2) Description of any observable marine mammal behavior patterns, 
including bearing and direction of travel and distance from pile 
driving activity;
    (3) Location and distance from pile driving activities to marine 
mammals and distance from the marine mammals to the observation point;
    (4) Estimated amount of time that the animals remained in the Level 
B zone
     Description of implementation of mitigation measures 
within each monitoring period (e.g., shutdown or delay);
     Other human activity in the area.
     A summary of the following must be included in the report.
    (1) Total number of individuals of each species detected within the 
Level A and Level B Zones, and estimated take extrapolated across 
entire Level B zone; and
    (2) Daily average number of individuals of each species 
(differentiated by month as appropriate) detected within the Level B 
Zone, and estimated take extrapolated across entire Level B zone.
    If no comments are received from NMFS within 30 days, the draft 
final report will constitute the final report. If

[[Page 18823]]

comments are received, a final report addressing NMFS comments must be 
submitted within 30 days after receipt of comments.
    In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury, serious injury or mortality, Chevron 
would immediately cease the specified activities and report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, and the West Coast Regional Stranding 
Coordinator. The report would include the following information:
     Description of the incident;
     Environmental conditions (e.g., Beaufort sea state, 
visibility);
     Description of all marine mammal observations in the 24 
hours preceding the incident;
     Species identification or description of the animal(s) 
involved;
     Fate of the animal(s); and
     Photographs or video footage of the animal(s) (if 
equipment is available).
    Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with Chevron to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. Chevron would not be able 
to resume their activities until notified by NMFS via letter, email, or 
telephone.
    In the event that Chevron discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition as described in the next paragraph), 
Chevron would immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the West Coast Regional Stranding Coordinator. The report would 
include the same information identified in the paragraph above. 
Activities would be able to continue while NMFS reviews the 
circumstances of the incident. NMFS would work with Chevron to 
determine whether modifications in the activities are appropriate.
    In the event that Chevron discovers an injured or dead marine 
mammal and the lead PSO 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), Chevron would report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the West Coast Regional Stranding 
Coordinator within 24 hours of the discovery. Chevron would provide 
photographs or video footage (if available) or other documentation of 
the stranded animal sighting to NMFS and the Marine Mammal Stranding 
Network.

Hydroacoustic Monitoring

    Sound Source Verification (SSV) testing of would be conducted under 
this IHA. The purpose of the proposed acoustic monitoring plan is to 
collect underwater sound-level information at both near and distant 
locations during vibratory pile extraction and installation and impact 
pile installation. The plan provides a protocol for hydroacoustic 
measurements during pile driving operations. Acoustic monitoring would 
be conducted on a minimum of two of each pile type. Since little data 
exist for source levels associated with installation of 24-inch square 
concrete piles (including data on single strike sound exposure level 
metrics) Chevron would conduct in-situ measurements during installation 
of eight piles. The SSV testing would be conducted by an acoustical 
firm with prior experience conducting SSV testing. Final results would 
be sent to NMFS. Findings may be used to establish Level A and Level B 
isopleths during impact and vibratory driving. Any alterations to the 
shutdown or harassment zones based on testing data must be approved by 
NMFS. The Hydroacoustic Monitoring Plan is contained on the following 
NMFS website: https://www.fisheries.noaa.gov/national/marine-mammal-protection/incidental-take-authorizations-construction-activities.

Negligible Impact Analysis and Determination

    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 recruitment or survival (i.e., population-
level effects). An estimate of the number of 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 harassment, NMFS considers other factors, such as the 
likely nature of any responses (e.g., intensity, duration), the context 
of any responses (e.g., critical reproductive time or location, 
migration), 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's 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).
    Pile driving and extraction associated with Chevron's WMEP project 
as outlined previously have the potential to injure, disturb or 
displace marine mammals. Specifically, the specified activities may 
result in Level B harassment (behavioral disturbance) for seven marine 
mammal species authorized for take from underwater sound generated 
during pile driving operations. Level A harassment in the form of PTS 
may also occur to limited numbers of two species. No marine mammal 
stocks for which incidental take authorization are listed as threatened 
or endangered under the ESA or determined to be strategic or depleted 
under the MMPA. No serious injuries or mortalities are anticipated to 
occur as a result of Chevron's pile driving activities.
    A limited number of animals (29 harbor seals and 2 harbor 
porpoises) could experience Level A harassment in the form of PTS if 
they stay within the Level A harassment zone during impact driving of 
24-inch steel H-piles. Installation of these piles would occur over 
eight days and impact driving will not be the primary method of 
installation. The piles will mainly be installed only through vibratory 
driving. Impact driving will only be used if the vibrated pile 
encounters an obstruction such as an old sunken pile. It is unlikely 
that this would occur for all four piles projected to be installed each 
driving day. An assumption of four piles per day was used to calculate 
Level A zone sizes. If four piles did require impact installation on a 
single day it is unlikely that the same individual marine mammal would 
be within the relatively small Level A zone during the installation of 
every pile. In most instances impact driving will not be required at 
all. Furthermore, the degree of injury is expected to be mild and is 
not likely to affect the reproduction or survival of the individual 
animals. It is expected that, if hearing impairments

[[Page 18824]]

occurs, most likely the affected animal would lose a few dB in its 
hearing sensitivity, which in most cases is not likely to affect its 
survival and recruitment.
    The Level B takes that are anticipated and authorized are expected 
to be limited to short-term behavioral harassment. Marine mammals 
present near the action area and taken by Level B harassment would most 
likely show overt brief disturbance (e.g. startle reaction) and 
avoidance of the area from elevated noise level during pile driving. 
Repeated exposures of individuals to levels of sound that may cause 
Level B harassment are unlikely to significantly disrupt foraging 
behavior. Thus, even repeated Level B harassment of some small subset 
of the overall stock is unlikely to result in any significant realized 
decrease in fitness for the affected individuals, and thus would not 
result in any adverse impact to the stock as a whole.
    The project is not expected to have significant adverse effects on 
affected marine mammal habitat. The activities may cause fish to leave 
the area temporarily. This could impact 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 affected habitat, the impacts to marine mammal habitat are not 
expected to cause significant or long-term negative consequences.
    The likelihood that marine mammals will be detected by trained 
observers is high under the environmental conditions described for the 
project. The employment of the soft-start mitigation measure would also 
allow marine mammals in or near the shutdown and Level A zone zones to 
move away from the impact driving sound source. Therefore, the 
mitigation and monitoring measures are expected to reduce the potential 
for injury and reduce the amount and intensity of behavioral 
harassment. Furthermore, the pile driving activities analyzed here are 
similar to, or less impactful than, numerous construction activities 
conducted in other similar locations which have taken place with no 
reported injuries or mortality to marine mammals, and no known long-
term adverse consequences from behavioral harassment.
    In summary and as described above, the following factors primarily 
support our preliminary determination that the impacts resulting from 
this activity are not expected to adversely affect the species or stock 
through effects on annual rates of recruitment or survival:
     No mortality is anticipated or authorized;
     Anticipated incidences of Level A harassment would be in 
the form of a small degree of PTS to a limited number of animals;
     Anticipated incidents of Level B harassment consist of, at 
worst, temporary modifications in behavior;
     The relatively short and intermittent duration of in-water 
construction activities
     The small percentage of the stock that may be affected by 
project activities (< 17 percent for all stocks); and
     Efficacy of mitigation measures is expected to minimize 
the likelihood and severity of the level of harassment.
    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 the proposed activity will have a negligible impact on 
all affected marine mammal species or stocks.

Small Numbers

    As noted above, only small numbers of incidental take may be 
authorized under Section 101(a)(5)(D) of the MMPA for specified 
activities other than military readiness activities. The MMPA does not 
define small numbers and so, in practice, where estimated numbers are 
available, NMFS compares the number of individuals taken to the most 
appropriate estimation of abundance of the relevant species or stock in 
our determination of whether an authorization is limited to small 
numbers of marine mammals. Additionally, other qualitative factors may 
be considered in the analysis, such as the temporal or spatial scale of 
the activities.
    Table 14 depicts the number of animals that could be exposed to 
Level A and Level B harassment from work associated with Chevron's 
project. The analysis provided indicates that authorized takes account 
for no more than 17.4 percent of the populations of the stocks that 
could be affected. These are small numbers of marine mammals relative 
to the sizes of the affected stocks.
    Based on the analysis contained herein of the proposed activity 
(including the proposed mitigation and monitoring measures) and the 
anticipated take of marine mammals, NMFS preliminarily finds that small 
numbers of marine mammals will be taken relative to the population size 
of the affected species or stocks.

Unmitigable Adverse Impact Analysis and Determination

    There are no relevant subsistence uses of the affected marine 
mammal stocks or species implicated by this action. Therefore, NMFS has 
preliminarily 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)

    Section 7(a)(2) of the Endangered Species Act of 1973 (ESA: 16 
U.S.C. 1531 et seq.) requires that each Federal agency insure that any 
action it authorizes, funds, or carries out is not likely to jeopardize 
the continued existence of any endangered or threatened species or 
result in the destruction or adverse modification of designated 
critical habitat. To ensure ESA compliance for the issuance of IHAs, 
NMFS consults internally, in this case with the ESA Interagency 
Cooperation Division whenever we propose to authorize take for 
endangered or threatened species.
    No incidental take of ESA-listed species is proposed for 
authorization or expected to result from this activity. Therefore, NMFS 
has determined that formal consultation under section 7 of the ESA is 
not required for this action.

Proposed Authorization

    As a result of these preliminary determinations, NMFS proposes to 
issue an IHA to Chevron for conducting pile driving activities in San 
Francisco Bay from June 1, 2018 through May 31, 2019, provided the 
previously mentioned mitigation, monitoring, and reporting requirements 
are incorporated. This section contains a draft of the IHA itself. The 
wording contained in this section is proposed for inclusion in the IHA 
(if issued).
    1. This Incidental Harassment Authorization (IHA) is valid from 
June 1, 2018 through May 31, 2019. This IHA is valid only for pile 
driving and extraction activities associated with Chevron's WMEP 
project.
    2. General Conditions.
    (a) A copy of this IHA must be in the possession of Chevron, its 
designees, and work crew personnel operating under the authority of 
this IHA.
    (b) The species authorized for taking are of gray whale 
(Eschrichtius robustus), bottlenose dolphin (Tursiops truncatus), 
harbor porpoise (Phocoena phocoena), California sea lion (Zalophus 
californianus), Northern fur seal (Callorhinus ursinus), Pacific harbor 
seal (Phoca vitulina), and

[[Page 18825]]

Northern elephant seal Mirounga angustirostris).
    (c) The taking, by Level A and Level B harassment, is limited to 
the species listed in condition 2(b). See Table 14 for number of takes 
authorized.
    (d) The take of any other species not listed in condition 2(b) of 
marine mammal is prohibited and may result in the modification, 
suspension, or revocation of this IHA.
    (e) Chevron shall conduct briefings between construction 
supervisors and crews, marine mammal monitoring team, acoustical 
monitoring team prior to the start of all pile driving activities, and 
when new personnel join the work, in order to explain responsibilities, 
communication procedures, marine mammal monitoring protocol, and 
operational procedures.
    3. Mitigation Measures.
    The holder of this Authorization is required to implement the 
following mitigation measures:
    (a) Time Restrictions--For all in-water pile driving activities, 
Chevron shall operate only during daylight hours (7:00 a.m. to 7:00 
p.m.)
    (b) Seasonal Restriction--To minimize impacts to listed fish 
species, pile-driving activities shall occur between June 1 and 
November 30.
    (c) Establishment of Shutdown Zone--For all pile driving/removal 
and drilling activities, Chevron shall establish a shutdown zone. The 
shutdown isopleths for pinnipeds (harbor seals, California sea lion, 
Northern elephant seal, northern fur seal) and mid-frequency cetaceans 
(common dolphins) shall be set at 35 meters; for high-frequency 
cetaceans (harbor porpoises) at 250 meters; and for low-frequency 
cetaceans (gray whales) at 350 meters.
    (d) 10-Meter Shutdown Zone--During the in-water operation of heavy 
machinery (e.g., barge movements), a 10-m shutdown zone for all marine 
mammals shall be implemented. If a marine mammal comes within 10 m, 
operations shall cease and vessels shall reduce speed to the minimum 
level required to maintain steerage and safe working conditions.
    (e) Establishment of Monitoring Zones for Level A and Level B--
Chevron shall establish and monitor Level A harassment zones during 
impact driving for harbor seal extending to 183 meters and harbor 
porpoise extending to 408 meters. Chevron shall also establish and 
monitor Level B harassment zones as depicted in Table 8.
    (f) Soft Start--Chevron shall use soft start techniques when impact 
pile driving. Soft start requires contractors to provide an initial set 
of strikes at reduced energy, followed by a thirty-second waiting 
period, then two subsequent reduced energy strike sets. Soft start 
shall be implemented at the start of each day's impact pile driving and 
at any time following cessation of impact pile driving for a period of 
thirty minutes or longer.
    (g) Pre-Activity Monitoring--Pre-activity monitoring shall take 
place from 30 minutes prior to initiation of pile driving activity and 
post-activity monitoring shall continue through 30 minutes post-
completion of pile driving activity. Pile driving may commence at the 
end of the 30-minute pre-activity monitoring period, provided observers 
have determined that the shutdown zone is clear of marine mammals, 
which includes delaying start of pile driving activities if a marine 
mammal is sighted in the zone, as described below.
    (h) If a marine mammal approaches or enters the shutdown zone 
during activities or pre-activity monitoring, all pile driving 
activities at that location shall be halted or delayed, respectively. 
If pile driving is halted or delayed due to the presence of a marine 
mammal, the activity may not resume or commence until either the animal 
has voluntarily left and been visually confirmed beyond the shutdown 
zone and 15 minutes have passed without re-detection of the animal. 
Pile driving activities include the time to install or remove a single 
pile or series of piles, as long as the time elapsed between uses of 
the pile driving equipment is no more than thirty minutes.
    (i) Non-authorized Take Prohibited--If a species for which 
authorization has not been granted or a species for which authorization 
has been granted but the authorized takes are met, is observed 
approaching or within the monitoring zone, pile driving and removal 
activities must shut down immediately using delay and shut-down 
procedures. Activities must not resume until the animal has been 
confirmed to have left the area or an observation time period of 15 
minutes has elapsed.
    4. Monitoring.
    The holder of this Authorization is required to conduct visual 
marine mammal monitoring during pile driving activities:
    (a) Visual Marine Mammal Observation--The following visual 
monitoring measures shall be implemented.
    (i) Biological monitoring shall occur within one (1) week before 
the project's start date.
    (ii) Monitoring distances, in accordance with the identified 
shutdown zones, Level A and Level B zones, shall be determined by using 
a range finder, scope, hand-held global positioning system (GPS) device 
or landmarks with known distances from the monitoring positions.
    (iii) Monitoring locations shall be established at locations 
offering best views of the monitoring zone.
    (iv) At least two PSOs shall be actively scanning the monitoring 
zone during all pile driving activities.
    (v) Monitoring shall be continuous unless the contractor takes a 
break longer than 2 hours from active pile and sheet pile driving, in 
which case, monitoring shall be required 30 minutes prior to restarting 
pile installation.
    (vi) For in-water pile driving, under conditions of fog or poor 
visibility that might obscure the presence of a marine mammal within 
the shutdown zone or Level A zone, the pile in progress shall be 
completed and then pile driving suspended until visibility conditions 
improve.
    (vii) Monitoring of pile driving shall be conducted by qualified 
PSOs, who shall have no other assigned tasks during monitoring periods. 
Chevron shall adhere to the following conditions when selecting 
observers:
    (1) Independent PSOs shall be used (i.e., not construction 
personnel);
    (2) At least one PSO must have prior experience working as a marine 
mammal observer during construction activities;
    (3) Other PSOs may substitute education (degree in biological 
science or related field) or training for experience; and
    (4) Chevron shall submit PSO CVs for approval by NMFS.
    (viii) Chevron shall ensure that observers have the following 
additional qualifications:
    (1) Ability to conduct field observations and collect data 
according to assigned protocols;
    (2) Experience or training in the field identification of marine 
mammals, including the identification of behaviors;
    (3) Sufficient training, orientation, or experience with the 
construction operation to provide for personal safety during 
observations;
    (4) Writing skills sufficient to prepare a report of observations 
including but not limited to the number and species of marine mammals 
observed; dates and times when in-water construction activities were 
conducted; dates, times, and reason for implementation of mitigation 
(or why mitigation was not implemented when required); and marine 
mammal behavior; and
    (5) Ability to communicate orally, by radio or in person, with 
project personnel to provide real-time

[[Page 18826]]

information on marine mammals observed in the area as necessary.
    (b) Hydroacoustic Monitoring.
    (i) Sound Source Verification (SSV) testing shall be conducted as 
stipulated in the Hydroacoustic Monitoring Plan.
    (ii) Acoustic monitoring shall be conducted on a minimum of two of 
each pile type, except for 24-in square concrete piles shall require 
monitoring of 8 piles.
    (iii) Testing shall be conducted by an acoustical firm with prior 
experience conducting SSV testing.
    (iv) Final results shall be sent to NMFS and may be used to 
establish shutdown and monitoring isopleths.
    (v) Any alterations to the shutdown or monitoring zones based on 
testing data must be approved by NMFS.
    5. Reporting.
    (a) A draft marine mammal monitoring report shall be submitted to 
NMFS within 90 days after the completion of pile driving and removal 
activities or a minimum of 60 days prior to any subsequent IHAs. A 
final report shall be prepared and submitted to the NMFS within 30 days 
following receipt of comments on the draft report from the NMFS.
    (b) The report shall include an overall description of work 
completed, a narrative regarding marine mammal sightings, and 
associated marine mammal observation data sheets. Specifically, the 
report must include:
    (i) Date and time that monitored activity begins or ends;
    (ii) Construction activities occurring during each observation 
period;
    (iii) Weather parameters (e.g., percent cover, visibility);
    (iv) Water conditions (e.g., sea state, tide state);
    (v) Deviation from initial proposal in pile numbers, pile types, 
average driving times, etc.
    (vi) For each marine mammal sighting the following must be 
recorded:
    (1) Species, numbers, and, if possible, sex and age class of marine 
mammals;
    (2) Description of any observable marine mammal behavior patterns, 
including bearing and direction of travel and distance from pile 
driving activity;
    (3) Location and distance from pile driving activities to marine 
mammals and distance from the marine mammals to the observation point;
    (4) Estimated amount of time that the animals remained in the Level 
A and B zones
    (vii) Description of implementation of mitigation measures within 
each monitoring period (e.g., shutdown or delay);
    (viii) Other human activity in the area.
    (ix) The report must contain a summary of the following:
    (1) Total number of individuals of each species detected within the 
Level A and Level B Zones,
    (2) Estimated take extrapolated across entire Level B zone; and
    (3) Daily average number of individuals of each species 
(differentiated by month as appropriate) detected within the Level B 
Zone, and estimated take extrapolated across entire Level B zone.
    (x) If no comments are received from NMFS within 30 days, the draft 
final report shall constitute the final report. If comments are 
received, a final report addressing NMFS comments must be submitted 
within 30 days after receipt of comments.
    (c) In the unanticipated event that the specified activity clearly 
causes the take of a marine mammal in a manner prohibited by the IHA 
(if issued), such as an injury, serious injury or mortality, Chevron 
would immediately cease the specified activities and report the 
incident to the Chief of the Permits and Conservation Division, Office 
of Protected Resources, NMFS, and the West Coast Regional Stranding 
Coordinator. The report must include the following:
    (i) Description of the incident;
    (ii) Environmental conditions (e.g., Beaufort sea state, 
visibility);
    (iii) Description of all marine mammal observations in the 24 hours 
preceding the incident;
    (iv) Species identification or description of the animal(s) 
involved;
    (v) Fate of the animal(s); and
    (vi) Photographs or video footage of the animal(s) (if equipment is 
available).
    (vii) Activities would not resume until NMFS is able to review the 
circumstances of the prohibited take. NMFS would work with Chevron to 
determine what is necessary to minimize the likelihood of further 
prohibited take and ensure MMPA compliance. Chevron would not be able 
to resume their activities until notified by NMFS via letter, email, or 
telephone.
    (b) In the event that Chevron discovers an injured or dead marine 
mammal, and the lead PSO determines that the cause of the injury or 
death is unknown and the death is relatively recent (e.g., in less than 
a moderate state of decomposition as described in the next paragraph), 
Chevron would immediately report the incident to the Chief of the 
Permits and Conservation Division, Office of Protected Resources, NMFS, 
and the West Coast Regional Stranding Coordinator. The report would 
include the same information identified in section above. Activities 
would be able to continue while NMFS reviews the circumstances of the 
incident. NMFS would work with Chevron to determine whether 
modifications in the activities are appropriate.
    (c) In the event that Chevron discovers an injured or dead marine 
mammal and the lead PSO 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), Chevron would report the incident 
to the Chief of the Permits and Conservation Division, Office of 
Protected Resources, NMFS, and the West Coast Regional Stranding 
Coordinator within 24 hours of the discovery. Chevron would provide 
photographs or video footage (if available) or other documentation of 
the stranded animal sighting to NMFS and the Marine Mammal Stranding 
Network.
    6. This Authorization may be modified, suspended or withdrawn if 
the holder fails to abide by the conditions prescribed herein, or if 
NMFS determines the authorized taking is having more than a negligible 
impact on the species or stock of affected marine mammals.

Request for Public Comments

    We request comment on our analyses, the draft authorization, and 
any other aspect of this Notice of Proposed IHA for the proposed 
Chevron WMEP project. Please include with your comments any supporting 
data or literature citations to help inform our final decision on the 
request for MMPA authorization.
    On a case-by-case basis, NMFS may issue a one-year renewal IHA 
without additional notice when (1) another year of identical or nearly 
identical activities as described in the Specified Activities section 
is planned, or (2) the activities would not be completed by the time 
the IHA expires and renewal would allow completion of the activities 
beyond that described in the Dates and Duration section, provided all 
of the following conditions are met:
     A request for renewal is received no later than 60 days 
prior to expiration of the current IHA.
     The request for renewal must include the following:
    (1) An explanation that the activities to be conducted beyond the 
initial dates either are identical to the previously analyzed 
activities or include changes so minor (e.g., reduction in pile size) 
that the changes do not affect the previous analyses, take estimates, 
or

[[Page 18827]]

mitigation and monitoring requirements; and
    (2) A preliminary monitoring report showing the results of the 
required monitoring to date and an explanation showing that the 
monitoring results do not indicate impacts of a scale or nature not 
previously analyzed or authorized.
     Upon review of the request for renewal, the status of the 
affected species or stocks, and any other pertinent information, NMFS 
determines that there are no more than minor changes in the activities, 
the mitigation and monitoring measures remain the same and appropriate, 
and the original findings remain valid.

    Dated: April 24, 2018.
Donna S. Wieting,
Director, Office of Protected Resources, National Marine Fisheries 
Service.
[FR Doc. 2018-09033 Filed 4-27-18; 8:45 am]
 BILLING CODE 3510-22-P